326 results on '"Steven Grant"'
Search Results
2. Dual mTORC1/2 Inhibition Synergistically Enhances AML Cell Death in Combination with the BCL2 Antagonist Venetoclax
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Toshihisa Satta, Lin Li, Sri Lakshmi Chalasani, Xiaoyan Hu, Jewel Nkwocha, Kanika Sharma, Maciej Kmieciak, Mohamed Rahmani, Liang Zhou, and Steven Grant
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Cancer Research ,Oncology - Abstract
Purpose: Acute myelogenous leukemia (AML) is an aggressive disease with a poor outcome. We investigated mechanisms by which the anti-AML activity of ABT-199 (venetoclax) could be potentiated by dual mTORC1/TORC2 inhibition. Experimental Design: Venetoclax/INK128 synergism was assessed in various AML cell lines and primary patient AML samples in vitro. AML cells overexpressing MCL-1, constitutively active AKT, BAK, and/or BAX knockout, and acquired venetoclax resistance were investigated to define mechanisms underlying interactions. The antileukemic efficacy of this regimen was also examined in xenograft and patient-derived xenograft (PDX) models. Results: Combination treatment with venetoclax and INK128 (but not the mTORC1 inhibitor rapamycin) dramatically enhanced cell death in AML cell lines. Synergism was associated with p-AKT and p-4EBP1 downregulation and dependent upon MCL-1 downregulation and BAK/BAX upregulation as MCL-1 overexpression and BAX/BAK knockout abrogated cell death. Constitutive AKT activation opposed synergism between venetoclax and PI3K or AKT inhibitors, but not INK128. Combination treatment also synergistically induced cell death in venetoclax-resistant AML cells. Similar events occurred in primary patient-derived leukemia samples but not normal CD34+ cells. Finally, venetoclax and INK128 co-treatment displayed increased antileukemia effects in in vivo xenograft and PDX models. Conclusions: The venetoclax/INK128 regimen exerts significant antileukemic activity in various preclinical models through mechanisms involving MCL-1 downregulation and BAK/BAX activation, and offers potential advantages over PI3K or AKT inhibitors in cells with constitutive AKT activation. This regimen is active against primary and venetoclax-resistant AML cells, and in in vivo AML models. Further investigation of this strategy appears warranted.
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- 2023
3. Non-canonical role for the ataxia-telangiectasia-Rad3 pathway in STAT3 activation in human multiple myeloma cells
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Lin Li, Xiaoyan Hu, Jewel Nkwocha, Kanika Sharma, Maciej Kmieciak, Hashim Mann, Liang Zhou, and Steven Grant
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Cancer Research ,Oncology ,Molecular Medicine ,General Medicine - Abstract
Purpose The goal of this study was to characterize the relationship between ATR and STAT3 interactions in human multiple myeloma (MM) cells. Methods Various MM cell lines, including IL-6-dependent cells were exposed to ATR inhibitors and effects on STAT3 Tyr705 and Ser727 were monitored by WB analysis and ImageStream analysis. Parallel studies examined induction of cell death, STAT3 DNA binding activity, and expression of STAT3 downstream targets (BCL-XL, MCL-1, c-MYC). Validation was obtained in ATR shRNA knock-down cells, and in cells ectopically expressing BCL-XL, MCL-1, or c-MYC. Analogous studies were performed in primary MM cells and in a MM xenograft model. Results Multiple pharmacologic ATR inhibitors inhibited STAT3 Tyr705 (but not Ser727) phosphorylation at low uM concentrations and down-regulated BCL-XL, MCL-1, c-MYC in association with cell death induction. Compatible results were observed in ATR shRNA knock-down cells. Cell death induced by ATR inhibitors was significantly attenuated in cells ectopically expressing constitutively active STAT3, BCL-XL, MCL-1, or c-MYC. Concordant results were observed in primary human MM cells and in an in vivo MM xenograft model. Conclusions Collectively, these findings argue for a non-canonical role for the ATR kinase in STAT3 activation in MM cells, and suggest that STAT3 inactivation contributes to the lethal actions of ATR inhibitors in MM.
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- 2023
4. Mechanisms underlying synergism between circularized tumor necrosis factor‐related apoptosis inducing ligand and bortezomib in bortezomib‐sensitive or ‐resistant myeloma cells
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Yun Leng, Xiaoyan Hu, Lin Li, Jewel Nkwocha, Toshihisa Satta, Kanika Sharma, Maciej Kmeiciak, Huixing Zhou, Zhiyao Zhang, Liang Zhou, Wenming Chen, and Steven Grant
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Bortezomib ,Cancer Research ,Oncology ,Tumor Necrosis Factors ,NF-kappa B ,Humans ,Apoptosis ,Hematology ,General Medicine ,Ligands - Abstract
Mechanisms underlying interactions between a novel, clinically relevant circularized tumor necrosis factor-related apoptosis inducing ligand (TRAIL) agonist, circularly permuted TRAIL (CPT) have been examined in multiple myeloma (MM) cells sensitive or resistant to bortezomib (BTZ). Various MM cell lines for example, U266, including those resistant to bortezomib-resistant U266 cells were exposed to low nanomolar concentrations of bortezomib ± CPT and apoptosis monitored. Circularly permuted TRAIL and bortezomib synergistically induced apoptosis in both BTZ-naïve and -resistant cells. The regimen up-regulated DR4 receptor internalization in MM cells, known to modulate both NF-κB and extrinsic apoptotic pathways. CPT/BTZ disrupted the non-canonical NF-κB pathway, reflected by tumor necrosis factor (TNF) receptor associated factors 3 (TRAF3) up-regulation, NF-κB inducing kinase down-regulation, diminished p52 and p50 processing, and B-cell lymphoma-extra large (BCL-XL) down-regulation, but failed to inactivate the canonical NF-κB pathway, reflected by unchanged or increased expression of phospho-p65. The regimen also sharply increased extrinsic apoptotic pathway activation. Cells exhibiting TRAF3 knock-down, dominant-negative Fas-associated protein with death domain, knock-down of caspase-8, BCL-2/BCL-XL, or exposure to a caspase-9 inhibitor displayed markedly reduced CPT/BTZ sensitivity. Concordant results were observed in bortezomib-resistant cells. The regimen was also active in the presence of stromal cells and was relatively sparing toward normal CD34
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- 2022
5. Chk1 Inhibition Potently Blocks STAT3 Tyrosine705 Phosphorylation, DNA-Binding Activity, and Activation of Downstream Targets in Human Multiple Myeloma Cells
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Dipankar Bandyopadhyay, Yanxia Ning, Jonathan Yu, Said M. Sebti, Steven Grant, Jewel Nkwocha, Xin-Yan Pei, Liang Zhou, Xiaoyan Hu, Sri Lakshmi Chalasani, Yu Zhang, Lin Li, and Kanika Sharma
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STAT3 Transcription Factor ,Cancer Research ,Stromal cell ,DNA damage ,Apoptosis ,Article ,Dephosphorylation ,Cell Line, Tumor ,Humans ,Phosphorylation ,STAT3 ,Protein Kinase Inhibitors ,Molecular Biology ,biology ,Chemistry ,Kinase ,DNA ,Molecular biology ,Prexasertib ,Oncology ,Checkpoint Kinase 1 ,biology.protein ,Cancer research ,Multiple Myeloma - Abstract
The relationship between the checkpoint kinase Chk1 and the STAT3 pathway was examined in multiple myeloma cells. Gene expression profiling of U266 cells exposed to low (nmol/L) Chk1 inhibitor [PF-477736 (PF)] concentrations revealed STAT3 pathway-related gene downregulation (e.g., BCL-XL, MCL-1, c-Myc), findings confirmed by RT-PCR. This was associated with marked inhibition of STAT3 Tyr705 (but not Ser727) phosphorylation, dimerization, nuclear localization, DNA binding, STAT3 promoter activity by chromatin immunoprecipitation assay, and downregulation of STAT-3-dependent proteins. Similar findings were obtained in other multiple myeloma cells and with alternative Chk1 inhibitors (e.g., prexasertib, CEP3891). While PF did not reduce GP130 expression or modify SOCS or PRL-3 phosphorylation, the phosphatase inhibitor pervanadate antagonized PF-mediated Tyr705 dephosphorylation. Significantly, PF attenuated Chk1-mediated STAT3 phosphorylation in in vitro assays. Surface plasmon resonance analysis suggested Chk1/STAT3 interactions and PF reduced Chk1/STAT3 co-immunoprecipitation. Chk1 CRISPR knockout or short hairpin RNA knockdown cells also displayed STAT3 inactivation and STAT3-dependent protein downregulation. Constitutively active STAT3 diminished PF-mediated STAT3 inactivation and downregulate STAT3-dependent proteins while significantly reducing PF-induced DNA damage (γH2A.X formation) and apoptosis. Exposure of cells with low basal phospho-STAT3 expression to IL6 or human stromal cell conditioned medium activated STAT3, an event attenuated by Chk1 inhibitors. PF also inactivated STAT3 in primary human CD138+ multiple myeloma cells and tumors extracted from an NSG multiple myeloma xenograft model while inhibiting tumor growth. Implications: These findings identify a heretofore unrecognized link between the Chk1 and STAT3 pathways and suggest that Chk1 pathway inhibitors warrant attention as novel and potent candidate STAT3 antagonists in myeloma.
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- 2022
6. Enhancing venetoclax activity in hematological malignancies
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Steven Grant and Toshihisa Satta
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0301 basic medicine ,Antineoplastic Agents ,Apoptosis ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,immune system diseases ,hemic and lymphatic diseases ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Animals ,Humans ,Pharmacology (medical) ,MCL1 ,neoplasms ,Pharmacology ,Sulfonamides ,Venetoclax ,business.industry ,General Medicine ,Bridged Bicyclo Compounds, Heterocyclic ,medicine.disease ,Lymphoma ,Leukemia ,030104 developmental biology ,Proto-Oncogene Proteins c-bcl-2 ,chemistry ,Drug Resistance, Neoplasm ,Hematologic Neoplasms ,030220 oncology & carcinogenesis ,Cancer research ,Treatment strategy ,biological phenomena, cell phenomena, and immunity ,business - Abstract
INTRODUCTION: Targeting anti-apoptotic pathways involving the BCL2 family proteins represents a novel treatment strategy in hematologic malignancies. Venetoclax, a selective BCL2 inhibitor, represents the first approved agent of this class, and is currently used in CLL and AML. However, monotherapy is rarely sufficient for sustained responses due to development of drug resistance and loss of dependence upon the targeted protein. Numerous pre-clinical studies have shown that combining venetoclax with other agents may represent a more effective therapeutic strategy by circumventing resistance mechanisms. In this review, we summarize pre-clinical data providing a foundation for rational combination strategies involving venetoclax. AREAS COVERED: Novel combination strategies in hematologic malignancies involving venetoclax, primarily at the pre-clinical level, will be reviewed. We emphasize novel agents that interrupt complementary or compensatory pro-survival pathways, and particularly mechanistic insights underlying synergism. PubMed, Cochrane, EMBASE, and Google scholar were searched from 2000. EXPERT OPINION: Although venetoclax has proven to be an effective therapeutic in hematologic malignancies, monotherapy may be insufficient for maximal effectiveness due to the development of resistance and/or loss of BCL2 addiction. Further pre-clinical and clinical development of combination therapies may be necessary for optimal outcomes in patients with diverse blood cancers.
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- 2020
7. Concomitant targeting of BCL2 with venetoclax and MAPK signaling with cobimetinib in acute myeloid leukemia models
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Jun Chen, Sha S. Jin, Courtney D. DiNardo, Duncan H. Mak, Jing Wang, Paul Koller, Deepak Sampath, Vivian Ruvolo, Marina Konopleva, Steven Grant, Eugene Kim, Hagop M. Kantarjian, Elias Jabbour, Yang Zhao, Ce Shi, Mohamed Rahmani, Naval Daver, Monique Dail, Qi Zhang, Darren C. Phillips, Rodrigo Jacamo, Lina Han, Jared K. Burks, Antonio Cavazos, Joel D. Leverson, and Michael Andreeff
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MAPK/ERK pathway ,Acute Myeloid Leukemia ,Proteomics ,Myeloid ,Apoptosis ,Biology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Piperidines ,hemic and lymphatic diseases ,Cell Line, Tumor ,medicine ,Humans ,MCL1 ,Progenitor cell ,Cobimetinib ,Sulfonamides ,Venetoclax ,Myeloid leukemia ,Hematology ,medicine.disease ,Bridged Bicyclo Compounds, Heterocyclic ,Leukemia ,Leukemia, Myeloid, Acute ,medicine.anatomical_structure ,chemistry ,Proto-Oncogene Proteins c-bcl-2 ,Cancer research ,Azetidines ,Aticle ,030215 immunology - Abstract
The pathogenesis of acute myeloid leukemia (AML) involves serial acquisition of mutations controlling several cellular processes, requiring combination therapies affecting key downstream survival nodes in order to treat the disease effectively. The BCL2 selective inhibitor venetoclax has potent anti-leukemia efficacy; however, resistance can occur due to its inability to inhibit MCL1, which is stabilized by the MAPK pathway. In this study, we aimed to determine the anti-leukemia efficacy of concomitant targeting of the BCL2 and MAPK pathways by venetoclax and the MEK1/2 inhibitor cobimetinib, respectively. The combination demonstrated synergy in seven of 11 AML cell lines, including those resistant to single agents, and showed growth-inhibitory activity in over 60% of primary samples from patients with diverse genetic alterations. The combination markedly impaired leukemia progenitor functions, while maintaining normal progenitors. Mass cytometry data revealed that BCL2 protein is enriched in leukemia stem/progenitor cells, primarily in venetoclax-sensitive samples, and that cobimetinib suppressed cytokine-induced pERK and pS6 signaling pathways. Through proteomic profiling studies, we identified several pathways inhibited downstream of MAPK that contribute to the synergy of the combination. In OCI-AML3 cells, the combination downregulated MCL1 protein levels and disrupted both BCL2:BIM and MCL1:BIM complexes, releasing BIM to induce cell death. RNA sequencing identified several enriched pathways, including MYC, mTORC1, and p53 in cells sensitive to the drug combination. In vivo, the venetoclax-cobimetinib combination reduced leukemia burden in xenograft models using genetically engineered OCI-AML3 and MOLM13 cells. Our data thus provide a rationale for combinatorial blockade of MEK and BCL2 pathways in AML.
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- 2020
8. Functional role of DNMT1 in the anti-leukemic effects of hypomethylating agents in AML cells
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Lin, Li, Xiaoyan, Hu, Jewel, Nkwocha, Kanika, Sharma, Liang, Zhou, and Steven, Grant
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DNA (Cytosine-5-)-Methyltransferase 1 ,Leukemia, Myeloid, Acute ,Cancer Research ,Oncology ,Humans ,Hematology - Published
- 2022
9. The Covalent CDK7 Inhibitor THZ1 Potently Induces Apoptosis in Multiple Myeloma Cells In Vitro and In Vivo
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Kanika Sharma, Dipankar Bandyopadhyay, Alexander Allen, Maciej Kmieciak, Yu Zhang, Liang Zhou, and Steven Grant
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0301 basic medicine ,Cancer Research ,biology ,Bortezomib ,Cell growth ,Chemistry ,medicine.disease ,Carfilzomib ,CD19 ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,Oncology ,Downregulation and upregulation ,immune system diseases ,Apoptosis ,In vivo ,hemic and lymphatic diseases ,030220 oncology & carcinogenesis ,medicine ,biology.protein ,Cancer research ,Multiple myeloma ,medicine.drug - Abstract
Purpose: The goal of this study was to characterize the activity of the covalent CDK7 inhibitor THZ1 in multiple myeloma models. Experimental Design: Multiple myeloma lines were exposed to varying THZ1 concentrations alone or with carfilzomib or ABT-199, after which apoptosis was monitored by flow cytometry, protein expression by Western blot analysis, mRNA by RT-PCR. Analogous studies were performed in cells ectopically expressing c-MYC, MCL-1, or BCL-XL, or CRISPER-Cas CDK7 sgRNA knockout. Primary multiple myeloma cells were exposed to THZ1 ± carfilzomib or ABT-199. In vivo effects of THZ1 were examined in a systemic U266 xenograft model. Results: THZ1 markedly diminished multiple myeloma cell proliferation and survival despite bortezomib or stromal cell resistance in association with G2–M arrest, inactivation of CTD RNA Pol II, dephosphorylation of CDKs 7 as well as 1, 2, and 9, and MCL-1, BCL-xL, and c-MYC mRNA or protein downregulation. Ectopic MCL-1, c-MYC, or BCL-XL expression significantly protected cells from THZ1 lethality. Both THZ1 and CRISPR-Cas CDK7 knockout sharply diminished multiple myeloma cell proliferation and significantly increased carfilzomib and ABT-199 lethality. Parallel effects and interactions were observed in primary CD138+ (N = 22) or primitive multiple myeloma cells (CD138−/CD19+/CD20+/CD27+; N = 16). THZ1 administration [10 mg/kg i.p. twice daily (BID), 5 days/week] significantly improved survival in a systemic multiple myeloma xenograft model with minimal toxicity and induced similar events observed in vitro, for example, MCL-1 and c-MYC downregulation. Conclusions: THZ1 potently reduces multiple myeloma cell proliferation through transcriptional downregulation of MCL-1, BCL-XL, and c-MYC in vitro and in vivo. It warrants further attention as a therapeutic agent in multiple myeloma.
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- 2019
10. NOTCH1 Represses MCL-1 Levels in GSI-resistant T-ALL, Making them Susceptible to ABT-263
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Justine E. Roderick, Xunqin Yin, Jeffrey A. Engelman, Michelle A. Kelliher, Neha U. Patel, AHyun Choi, August Williams, Jessica L. Boisvert, Jorge A. Almenara, Cyril H. Benes, Ultan McDermott, Anthony C. Faber, Kathryn A. Rizzo, Anahita Dastur, Carlotta Costa, Steven Grant, Joseph McClanaghan, Max Greenberg, and Mathew J. Garnett
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0301 basic medicine ,Cancer Research ,Notch signaling pathway ,Apoptosis ,mTORC1 ,Drug resistance ,Mechanistic Target of Rapamycin Complex 1 ,Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ,Article ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,In vivo ,Cell Line, Tumor ,Animals ,Humans ,Medicine ,Receptor, Notch1 ,Receptor ,Cell Proliferation ,Sulfonamides ,Aniline Compounds ,Navitoclax ,business.industry ,In vitro ,3. Good health ,030104 developmental biology ,Oncology ,chemistry ,Drug Resistance, Neoplasm ,Cell culture ,030220 oncology & carcinogenesis ,Cancer research ,Heterografts ,Myeloid Cell Leukemia Sequence 1 Protein ,Amyloid Precursor Protein Secretases ,business ,Signal Transduction - Abstract
Purpose: Effective targeted therapies are lacking for refractory and relapsed T-cell acute lymphoblastic leukemia (T-ALL). Suppression of the NOTCH pathway using gamma-secretase inhibitors (GSI) is toxic and clinically not effective. The goal of this study was to identify alternative therapeutic strategies for T-ALL. Experimental Design: We performed a comprehensive analysis of our high-throughput drug screen across hundreds of human cell lines including 15 T-ALL models. We validated and further studied the top hit, navitoclax (ABT-263). We used multiple human T-ALL cell lines as well as primary patient samples, and performed both in vitro experiments and in vivo studies on patient-derived xenograft models. Results: We found that T-ALL are hypersensitive to navitoclax, an inhibitor of BCL2 family of antiapoptotic proteins. Importantly, GSI-resistant T-ALL are also susceptible to navitoclax. Sensitivity to navitoclax is due to low levels of MCL-1 in T-ALL. We identify an unsuspected regulation of mTORC1 by the NOTCH pathway, resulting in increased MCL-1 upon GSI treatment. Finally, we show that pharmacologic inhibition of mTORC1 lowers MCL-1 levels and further sensitizes cells to navitoclax in vitro and leads to tumor regressions in vivo. Conclusions: Our results support the development of navitoclax, as single agent and in combination with mTOR inhibitors, as a new therapeutic strategy for T-ALL, including in the setting of GSI resistance.
- Published
- 2019
11. Homoharringtonine interacts synergistically with bortezomib in NHL cells through MCL-1 and NOXA-dependent mechanisms
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Steven Grant, Rebecca E. Parker, William Craun, Tri Nguyen, Maciej Kmieciak, Yu Zhang, and Elisa Hawkins
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0301 basic medicine ,Cancer Research ,Apoptosis ,Lymphoma, Mantle-Cell ,Mice, SCID ,Bortezomib ,Mice ,0302 clinical medicine ,Mice, Inbred NOD ,immune system diseases ,hemic and lymphatic diseases ,medicine.diagnostic_test ,Chemistry ,Drug Synergism ,Diffuse large B-cell lymphoma ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,3. Good health ,Up-Regulation ,Oncology ,Proto-Oncogene Proteins c-bcl-2 ,030220 oncology & carcinogenesis ,Homoharringtonine ,Lymphoma, Large B-Cell, Diffuse ,Proteasome Inhibitors ,medicine.drug ,Research Article ,Signal Transduction ,Programmed cell death ,Homoharringtonine (Omacataxine) ,Down-Regulation ,lcsh:RC254-282 ,Flow cytometry ,03 medical and health sciences ,Cell Line, Tumor ,Genetics ,medicine ,otorhinolaryngologic diseases ,Animals ,Humans ,neoplasms ,Mantle cell lymphoma ,medicine.disease ,Xenograft Model Antitumor Assays ,030104 developmental biology ,Proteasome inhibitor ,Cancer research ,Myeloid Cell Leukemia Sequence 1 Protein - Abstract
Background Interactions between the protein synthesis inhibitor homoharringtonine (HHT) and the proteasome inhibitor bortezomib were investigated in DLBCL and mantle cell lymphoma cells (MCL). Methods Various DLBCL and MCL cells were exposed to HHT and bortezomib alone or together after which apoptosis and signaling pathway perturbations were monitored by flow cytometry and Western blot analysis. Xenograft mouse models were used to assess tumor growth and animal survival. Results HHT and bortezomib co-administration synergistically induced apoptosis in GC-, ABC- and double-hit DLBCL cells. Similar interactions were observed in MCL cells and in primary lymphoma cells. HHT/bortezomib co-administration diminished binding of MCL-1 to both BAK and NOXA. Knock-down of NOXA significantly diminished lethality whereas MCL-1 knock-down or ectopic NOXA expression increased cell death. Notably, HHT/bortezomib lethality was dramatically reduced in BAK knockout or knockdown cells. Finally, HHT/bortezomib co-administration significantly improved survival compared to single agents in GC- and ABC- xenograft models while exhibiting little toxicity. Conclusions These findings indicate that HHT and bortezomib cooperate to kill DLBCL and MCL cells through a process involving MCL-1 down-regulation, NOXA up-regulation, and BAK activation. They also suggest that a strategy combining HHT with bortezomib warrants attention in DLBCL and MCL. Electronic supplementary material The online version of this article (10.1186/s12885-018-5018-x) contains supplementary material, which is available to authorized users.
- Published
- 2018
12. Targeting cereblon in AML
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Steven Grant
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Myeloid ,Ubiquitin-Protein Ligases ,Immunology ,Biology ,Biochemistry ,medicine ,Humans ,Lenalidomide ,chemistry.chemical_classification ,DNA ligase ,Myeloid Neoplasia ,Stem Cells ,Cereblon ,Cell Biology ,Hematology ,medicine.disease ,Thalidomide ,Leukemia, Myeloid, Acute ,Leukemia ,medicine.anatomical_structure ,chemistry ,Cancer research ,Stem cell ,medicine.drug - Abstract
A number of clinically validated drugs have been developed by repurposing the CUL4-DDB1-CRBN-RBX1 (CRL4(CRBN)) E3 ubiquitin ligase complex with molecular glue degraders to eliminate disease-driving proteins. Here, we present the identification of a first-in-class GSPT1-selective cereblon E3 ligase modulator, CC-90009. Biochemical, structural, and molecular characterization demonstrates that CC-90009 coopts the CRL4(CRBN) to selectively target GSPT1 for ubiquitination and proteasomal degradation. Depletion of GSPT1 by CC-90009 rapidly induces acute myeloid leukemia (AML) apoptosis, reducing leukemia engraftment and leukemia stem cells (LSCs) in large-scale primary patient xenografting of 35 independent AML samples, including those with adverse risk features. Using a genome-wide CRISPR-Cas9 screen for effectors of CC-90009 response, we uncovered the ILF2 and ILF3 heterodimeric complex as a novel regulator of cereblon expression. Knockout of ILF2/ILF3 decreases the production of full-length cereblon protein via modulating CRBN messenger RNA alternative splicing, leading to diminished response to CC-90009. The screen also revealed that the mTOR signaling and the integrated stress response specifically regulate the response to CC-90009 in contrast to other cereblon modulators. Hyperactivation of the mTOR pathway by inactivation of TSC1 and TSC2 protected against the growth inhibitory effect of CC-90009 by reducing CC-90009-induced binding of GSPT1 to cereblon and subsequent GSPT1 degradation. On the other hand, GSPT1 degradation promoted the activation of the GCN1/GCN2/ATF4 pathway and subsequent apoptosis in AML cells. Collectively, CC-90009 activity is mediated by multiple layers of signaling networks and pathways within AML blasts and LSCs, whose elucidation gives insight into further assessment of CC-90009s clinical utility. These trials were registered at www.clinicaltrials.gov as #NCT02848001 and #NCT04336982).
- Published
- 2021
13. Phase 1 study of belinostat (PXD-101) and bortezomib (Velcade, PS-341) in patients with relapsed or refractory acute leukemia and myelodysplastic syndrome
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Prithviraj Bose, Guillermo Garcia-Manero, Wen Wan, John D. Roberts, Sandeep S. Dave, Elizabeth B. Collins, Steven Grant, Ellen Shrader, Victor Yazbeck, Caryn Weir, Dipankar Bandyopadhyay, Maciej Kmieciak, Amanda Garnett, Danielle Shafer, Mary Beth Tombes, and Beata Holkova
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Oncology ,Adult ,Cancer Research ,medicine.medical_specialty ,Blast Crisis ,Phases of clinical research ,Hydroxamic Acids ,Article ,Bortezomib ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Refractory ,Internal medicine ,hemic and lymphatic diseases ,Antineoplastic Combined Chemotherapy Protocols ,Medicine ,Humans ,In patient ,neoplasms ,Acute leukemia ,Sulfonamides ,Adult patients ,business.industry ,Hematology ,Leukemia, Myeloid, Acute ,Treatment Outcome ,chemistry ,030220 oncology & carcinogenesis ,Myelodysplastic Syndromes ,business ,Belinostat ,030215 immunology ,medicine.drug - Abstract
We report the results of a phase 1 dose-escalation study of belinostat and bortezomib in adult patients with acute leukemia or MDS or CML with blast crisis. Thirty-eight patients received IV belinostat days 1-5 and 8-12 with IV bortezomib days 1, 4, 8, and 11 every 21 days. QTc prolongation was the only identified DLT. The RP2Ds were 1.3 mg/m(2) bortezomib and 1000 mg/m(2) belinostat. One patient with highly refractory MLL-ENL rearranged biphenotypic AML with multiple karyotypic aberrations had a complete pathologic and karyotypic response. One patient with post-MPN AML remained on study with stable disease (SD) for 32 cycles. Whole-exome sequencing revealed no aberrations in the first patient and a hyper-mutator genotype in the second. Eighteen patients had a best response of SD. We conclude that this treatment strategy is feasible but has limited activity in this population. Nevertheless, the factors that predict exceptional responses to this strategy warrant further investigation.
- Published
- 2020
14. IAP and HDAC inhibitors interact synergistically in myeloma cells through noncanonical NF-κB- and caspase-8-dependent mechanisms
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Lora Kramer, Yanxia Ning, Mark B. Meads, Praneeth Reddy Sudalagunta, Ariosto S. Silva, Raghunandan Reddy Alugubelli, Rafael Renatino Canevarolo, Maria D Coelho Siqueira Silva, Danny Bui, Liang Zhou, Maciej Kmeiciak, Andrea Ferreira-Gonzalez, Jewel Nkwocha, Steven Grant, Jacquelyn McCarter, Kanika Sharma, Kenneth H. Shain, Yu Zhang, Lin Li, Gabriel De Avila, Cullen Purcell, Rebecca E. Parker, Xiaoyan Hu, and Yun Dai
- Subjects
Caspase 8 ,Lymphoid Neoplasia ,biology ,Apoptosis Inhibitor ,medicine.drug_class ,Histone deacetylase inhibitor ,NF-kappa B ,Hematology ,Inhibitor of apoptosis ,Histone Deacetylase Inhibitors ,chemistry.chemical_compound ,Mice ,Cell killing ,chemistry ,Downregulation and upregulation ,Panobinostat ,Cell Line, Tumor ,biology.protein ,Cancer research ,medicine ,Animals ,Humans ,FADD ,Multiple Myeloma - Abstract
Interactions between the inhibitor of apoptosis protein antagonist LCL161 and the histone deacetylase inhibitor panobinostat (LBH589) were examined in human multiple myeloma (MM) cells. LCL161 and panobinostat interacted synergistically to induce apoptosis in diverse MM cell lines, including those resistant to bortezomib (PS-R). Similar interactions were observed with other histone deacetylase inhibitors (MS-275) or inhibitors of apoptosis protein antagonists (birinapant). These events were associated with downregulation of the noncanonical (but not the canonical) NF-κB pathway and activation of the extrinsic, caspase-8–related apoptotic cascade. Coexposure of MM cells to LCL161/LBH589 induced TRAF3 upregulation and led to TRAF2 and NIK downregulation, diminished expression of BCL-XL, and induction of γH2A.X. Ectopic expression of TRAF2, NIK, or BCL-XL, or short hairpin RNA TRAF3 knock-down, significantly reduced LCL161/LBH589 lethality, as did ectopic expression of dominant-negative FADD. Stromal/microenvironmental factors failed to diminish LCL161/LBH589–induced cell death. The LCL161/LBH589 regimen significantly increased cell killing in primary CD138+ cells (N = 31) and was particularly effective in diminishing the primitive progenitor cell–enriched CD138–/19+/20+/27+ population (N = 23) but was nontoxic to normal CD34+ cells. Finally, combined LCL161/LBH589 treatment significantly increased survival compared with single-agent treatment in an immunocompetent 5TGM1 murine MM model. Together, these findings argue that LCL161 interacts synergistically with LBH589 in MM cells through a process involving inactivation of the noncanonical NF-κB pathway and activation of the extrinsic apoptotic pathway, upregulation of TRAF3, and downregulation of TRAF2/BCL-XL. Notably, this regimen overcomes various forms of resistance, is active against primary MM cells, and displays significant in vivo activity. This strategy warrants further consideration in MM.
- Published
- 2020
15. Recruiting TP53 to target chronic myeloid leukemia stem cells
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Steven Grant
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business.industry ,Editorials ,Fusion Proteins, bcr-abl ,Myeloid leukemia ,Proto-Oncogene Proteins c-mdm2 ,Hematology ,Disease Models, Animal ,Mice ,Drug Resistance, Neoplasm ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Cancer research ,Neoplastic Stem Cells ,Medicine ,Animals ,Stem cell ,business ,Protein Kinase Inhibitors ,Cell Proliferation - Abstract
Although highly effective, BCR-ABL1 tyrosine kinase inhibitors do not target chronic myeloid leukemia (CML) stem cells. Most patients relapse upon tyrosine kinase inhibitor therapy cessation. We reported previously that combined BCR-ABL1 and BCL-2 inhibition synergistically targets CML stem/progenitor cells. p53 induces apoptosis mainly by modulating BCL-2 family proteins. Although infrequently mutated in CML, p53 is antagonized by MDM2, which is regulated by BCR-ABL1 signaling. We hypothesized that MDM2 inhibition could sensitize CML cells to tyrosine kinase inhibitors. Using an inducible transgenic Scl-tTa
- Published
- 2020
16. Cotargeting BCL-2 and PI3K Induces BAX-Dependent Mitochondrial Apoptosis in AML Cells
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Mohamed Rahmani, Andrea Ferreira-Gonzalez, Rebecca E. Parker, Steven Grant, Xin-Yan Pei, Maciej Kmieciak, Jewel Nkwocha, Deepak Sampath, Elisa Hawkins, and Joel D. Leverson
- Subjects
0301 basic medicine ,Cancer Research ,Myeloid ,CD34 ,Down-Regulation ,Apoptosis ,Mice, SCID ,Article ,Mice ,Phosphatidylinositol 3-Kinases ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Mice, Inbred NOD ,Cell Line, Tumor ,hemic and lymphatic diseases ,medicine ,Animals ,Humans ,neoplasms ,Protein kinase B ,PI3K/AKT/mTOR pathway ,bcl-2-Associated X Protein ,Sulfonamides ,Venetoclax ,Myeloid leukemia ,U937 Cells ,Bridged Bicyclo Compounds, Heterocyclic ,medicine.disease ,Mitochondria ,Leukemia, Myeloid, Acute ,Leukemia ,Pyrimidines ,030104 developmental biology ,medicine.anatomical_structure ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,chemistry ,030220 oncology & carcinogenesis ,Cancer research ,Heterografts ,Apoptosis Regulatory Proteins - Abstract
Inhibitors targeting BCL-2 apoptotic proteins have significant potential for the treatment of acute myeloid leukemia (AML); however, complete responses are observed in only 20% of patients, suggesting that targeting BCL-2 alone is insufficient to yield durable responses. Here, we assessed the efficacy of coadministration of the PI3K/mTOR inhibitor GDC-0980 or the p110β-sparing PI3K inhibitor taselisib with the selective BCL-2 antagonist venetoclax in AML cells. Tetracycline-inducible downregulation of BCL-2 significantly sensitized MV4-11 and MOLM-13 AML cells to PI3K inhibition. Venetoclax/GDC-0980 coadministration induced rapid and pronounced BAX mitochondrial translocation, cytochrome c release, and apoptosis in various AML cell lines in association with AKT/mTOR inactivation and MCL-1 downregulation; ectopic expression of MCL-1 significantly protected cells from this regimen. Combined treatment was also effective against primary AML blasts from 17 patients, including those bearing various genetic abnormalities. Venetoclax/GDC-0980 markedly induced apoptosis in primitive CD34+/38−/123+ AML cell populations but not in normal hematopoietic progenitor CD34+ cells. The regimen was also active against AML cells displaying intrinsic or acquired venetoclax resistance or tumor microenvironment–associated resistance. Either combinatorial treatment markedly reduced AML growth and prolonged survival in a systemic AML xenograft mouse model and diminished AML growth in two patient-derived xenograft models. Venetoclax/GDC-0980 activity was partially diminished in BAK−/− cells and failed to induce apoptosis in BAX−/− and BAX−/−BAK−/− cells, whereas BIM−/− cells were fully sensitive. Similar results were observed with venetoclax alone in in vitro and in vivo systemic xenograft models. Collectively, these studies demonstrate that venetoclax/GDC-0980 exhibits potent anti-AML activity primarily through BAX and, to a lesser extent, BAK. These findings argue that dual BCL-2 and PI3K inhibition warrants further evaluation in AML. Significance: Combined treatment with clinically relevant PI3K and BCL-2 inhibitors may prove effective in the treatment of acute myeloid leukemia. Cancer Res; 78(11); 3075–86. ©2018 AACR.
- Published
- 2018
17. Flavopiridol enhances ABT-199 sensitivity in unfavourable-risk multiple myeloma cells in vitro and in vivo
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Liang Zhou, Joel D. Leverson, Deepak Sampath, Steven Grant, Matthew Nguyen, Yun Dai, Robert Z. Orlowski, Maciej Kmieciak, and Yu Zhang
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0301 basic medicine ,Cancer Research ,Cell ,Apoptosis ,Mice ,chemistry.chemical_compound ,0302 clinical medicine ,Piperidines ,Antineoplastic Combined Chemotherapy Protocols ,Sulfonamides ,Gene knockdown ,Bcl-2-Like Protein 11 ,Chemistry ,Drug Synergism ,Alvocidib ,Up-Regulation ,myeloma ,medicine.anatomical_structure ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,Gene Knockdown Techniques ,ABT-199 ,030220 oncology & carcinogenesis ,Multiple Myeloma ,Programmed cell death ,Primary Cell Culture ,Down-Regulation ,BCL-2 ,Antineoplastic Agents ,Risk Assessment ,CDK9 inhibitor ,03 medical and health sciences ,Downregulation and upregulation ,In vivo ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Flavonoids ,Bridged Bicyclo Compounds, Heterocyclic ,Cyclin-Dependent Kinase 9 ,In vitro ,030104 developmental biology ,flavopiridol ,Drug Resistance, Neoplasm ,Cell culture ,Cancer research ,Myeloid Cell Leukemia Sequence 1 Protein ,MCL-1 ,Translational Therapeutics ,Neoplasm Transplantation - Abstract
Background: The BCL-2-specific BH3-mimetic ABT-199 (venetoclax) has been reported to be principally active against favourable-risk multiple myeloma (MM) cells, prompting efforts to extend its activity to include more resistant, higher-risk MM subsets. Methods: Effects of the CDK9 inhibitor flavopiridol (FP; alvocidib) on responses to ABT-199 were examined in MM cells. Cell death and protein expression were evaluated by western blot and immunofluorescence. Xenograft models were used to study combination effects in vivo. Results: FP synergistically increased ABT-199 lethality in both ABT-199-sensitive and insensitive MM cells. FP blocked CDK9 activation/positive transcription elongation factor B phosphorylation, downregulated MCL-1, increased BCL-2/MCL-1 ratios, and upregulated BIM. MCL-1 ectopic expression or knockdown in MM cells significantly diminished or increased ABT-199 sensitivity, respectively. CDK9 knockdown triggered MCL-1 downregulation and increased ABT-199 activity, whereas BIM knockdown significantly reduced FP/ABT-199 lethality. FP also enhanced ABT-199 lethality in unfavourable prognosis primary MM cells. HS-5 cell co-culture failed to protect MM cells from the FP/ABT-199 regimen, suggesting circumvention of microenvironmental signals. Finally, FP/ABT-199 significantly increased survival in systemic xenograft and immune-competent MM models while exhibiting minimal toxicity. Conclusions: These findings argue that CDK9 inhibitors, for example, FP may increase the antimyeloma activity of ABT-199, including in unfavourable-risk MM minimally responsive to ABT-199 alone.
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- 2017
18. Rational combination strategies to enhance venetoclax activity and overcome resistance in hematologic malignancies
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Steven Grant
- Subjects
0301 basic medicine ,Cancer Research ,Myeloid ,Cell Survival ,Biology ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Acquired resistance ,Downregulation and upregulation ,Antineoplastic Combined Chemotherapy Protocols ,Biomarkers, Tumor ,medicine ,Humans ,Molecular Targeted Therapy ,Sulfonamides ,Venetoclax ,Logical approach ,Hematology ,Bridged Bicyclo Compounds, Heterocyclic ,Survival pathways ,Family member ,030104 developmental biology ,medicine.anatomical_structure ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,chemistry ,Drug Resistance, Neoplasm ,Hematologic Neoplasms ,Immunology ,Cancer research - Abstract
Venetoclax (ABT-199) is a Bcl-2-specific BH3-mimetic that has shown significant promise in certain subtypes of CLL as well as in several other hematologic malignancies. As in the case of essentially all targeted agents, intrinsic or acquired resistance to this agent generally occurs, prompting the search for new strategies capable of circumventing this problem. A logical approach to this challenge involves rational combination strategies designed to disable preexisting or induced compensatory survival pathways. Many of these strategies involve downregulation of Mcl-1, a pro-survival Bcl-2 family member that is not targeted by venetoclax, and which often confers resistance to this agent. Given encouraging clinical results involving venetoclax in both lymphoid and myeloid malignancies, it is likely that such combination approaches will be incorporated into the therapeutic armamentarium for multiple hematologic malignancies in the near future.
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- 2017
19. Positive transcription elongation factor b (P-TEFb) is a therapeutic target in human multiple myeloma
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Yu Zhang, Yun Leng, Yun Dai, Steven Grant, Liang Zhou, and Robert Z. Orlowski
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0301 basic medicine ,medicine.medical_specialty ,Cyclin T1 ,P-TEFb ,03 medical and health sciences ,chemistry.chemical_compound ,immune system diseases ,Cyclin-dependent kinase ,hemic and lymphatic diseases ,Internal medicine ,medicine ,Dinaciclib ,Multiple myeloma ,Hematology ,biology ,Bortezomib ,business.industry ,Alvocidib ,medicine.disease ,Carfilzomib ,3. Good health ,myeloma ,030104 developmental biology ,Oncology ,chemistry ,bortezomib resistance ,Immunology ,biology.protein ,Cancer research ,MCL-1 ,business ,CDK inhibitors ,Research Paper ,medicine.drug - Abstract
// Yu Zhang 1, * , Liang Zhou 1, * , Yun Leng 1, 2 , Yun Dai 3 , Robert Z. Orlowski 4 and Steven Grant 1, 5, 6, 7 1 Division of Hematology/Oncology, Department of Medicine, Virginia Commonwealth University and The Massey Cancer Center, Richmond, VA, USA 2 Department of Hematology, Beijing Chaoyang Hospital of Capital Medical University, Beijing, China 3 Cancer Center, The First Hospital of Jilin University, Changchun, China 4 Department of Myeloma and Lymphoma, MD Anderson Cancer Center, Houston, TX, USA 5 Virginia Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, VA, USA 6 Department of Biochemistry, Virginia Commonwealth University, Richmond, VA, USA 7 Department of Pharmacology Virginia Commonwealth University, Richmond, VA, USA * These authors contributed equally to this work Correspondence to: Steven Grant, email: steven.grant@vcuhealth.org Keywords: P-TEFb, bortezomib resistance, myeloma, MCL-1, CDK inhibitors Abbreviations: Alvocidib (Flavopiridol, FP); Dinaciclib (SCH727965, SCH); Bortezomib (btz); Carfilzomib (cfz); Hematoxylin and eosin (HE and b) marked CDK9 (42 kDa) T186 phosphorylation. In marked contrast, normal hematopoietic cells failed to exhibit up-regulation of p-CTD, CDK9, cyclin T1, or Mcl-1. CDK9 or cyclin T1 shRNA knock-down dramatically inhibited CTD S2 phosphorylation and down-regulated Mcl-1. Moreover, CRISPR-Cas CDK9 knock-out triggered apoptosis in MM cells and dramatically diminished cell growth. Pan-CDK e.g., dinaciclib or alvocidib and selective CDK9 inhibitors (CDK9i) recapitulated the effects of genetic P-TEFb disruption. CDK9 shRNA or CDK9 inhibitors significantly potentiated the susceptibility of MM cells, including bortezomib-resistant cells, to proteasome inhibitors. Analogously, CDK9 or cyclin T1 knock-down or CDK9 inhibitors markedly increased BH3-mimetic lethality in bortezomib-resistant cells. Finally, pan-CDK inhibition reduced human drug-naive or bortezomib-resistant CD138 + cells and restored bone marrow architecture in vivo . Collectively, these findings implicate constitutive P-TEFb activation in high Mcl-1 maintenance in MM, and validate targeting the P-TEFb complex to circumvent bortezomib-resistance.
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- 2017
20. Synergistic interactions between PLK1 and HDAC inhibitors in non-Hodgkin's lymphoma cells occur in vitro and in vivo and proceed through multiple mechanisms
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Akhil Kolluri, Rebecca E. Parker, Maciej Kmieciak, Mohamed Rahmani, Steven Grant, Tri K. Nguyen, Victor Yazbeck, Beata Holkova, and Elisa Hawkins
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0301 basic medicine ,Genes, myc ,Cell Cycle Proteins ,Hydroxamic Acids ,Histones ,Mice ,chemistry.chemical_compound ,0302 clinical medicine ,belinostat ,immune system diseases ,hemic and lymphatic diseases ,volasertib ,Sulfonamides ,Hematology ,Lymphoma, Non-Hodgkin ,Pteridines ,Histone deacetylase inhibitor ,Drug Synergism ,Volasertib ,3. Good health ,Gene Expression Regulation, Neoplastic ,Oncology ,Caspases ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Research Paper ,non-Hodgkin's lymphoma ,medicine.medical_specialty ,medicine.drug_class ,Protein Serine-Threonine Kinases ,03 medical and health sciences ,Cell Line, Tumor ,Proto-Oncogene Proteins ,Internal medicine ,medicine ,Animals ,Humans ,Protein Kinase Inhibitors ,Cell Proliferation ,business.industry ,Correction ,Cancer ,Cell Cycle Checkpoints ,Hematopoietic Stem Cells ,medicine.disease ,Xenograft Model Antitumor Assays ,Non-Hodgkin's lymphoma ,Lymphoma ,Histone Deacetylase Inhibitors ,Disease Models, Animal ,030104 developmental biology ,chemistry ,Immunology ,Cancer research ,Genes, Lethal ,Mantle cell lymphoma ,business ,Belinostat ,DNA Damage - Abstract
// Tri Nguyen 1 , Rebecca Parker 1 , Elisa Hawkins 1 , Beata Holkova 1 , Victor Yazbeck 1 , Akhil Kolluri 1 , Maciej Kmieciak 5 , Mohamed Rahmani 1 and Steven Grant 1, 2, 3, 4, 5 1 Division of Hematology/Oncology, Department of Internal Medicine, Virginia Commonwealth University and the Massey Cancer Center, Richmond, VA, USA 2 Departments of Biochemistry, Virginia Commonwealth University, Richmond, VA, USA 3 Departments of Pharmacology, Virginia Commonwealth University, Richmond, VA, USA 4 Virginia Institute for Molecular Medicine, Virginia Commonwealth University, Richmond, VA, USA 5 Massey Cancer Center, Virginia Commonwealth University Health Sciences Center, Richmond, VA, USA Correspondence to: Steven Grant, email: steven.grant@vcuhealth.org Keywords: non-Hodgkin’s lymphoma, volasertib, belinostat Received: August 17, 2016 Accepted: November 22, 2016 Published: February 23, 2017 ABSTRACT Interactions between the polo-like kinase 1 (PLK1) inhibitor volasertib and the histone deacetylase inhibitor (HDACI) belinostat were examined in diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) cells in vitro and in vivo. Exposure of DLBCL cells to very low concentrations of volasertib in combination with belinostat synergistically increased cell death (apoptosis). Similar interactions occurred in GC-, ABC-, double-hit DLBCL cells, MCL cells, bortezomib-resistant cells and primary lymphoma cells. Co-exposure to volasertib/belinostat induced a marked increase in M-phase arrest, phospho-histone H3, mitotic errors, cell death in M-phase, and DNA damage. Belinostat diminished c-Myc mRNA and protein expression, an effect significantly enhanced by volasertib co-exposure. c-Myc knock-down increased DNA damage and cell death in response to volasertib, arguing that c-Myc down-regulation plays a functional role in the lethality of this regimen. Notably, PLK1 knock-down in DLBCL cells significantly increased belinostat-induced M-phase accumulation, phospho-histone H3, γH2AX, and cell death. Co-administration of volasertib and belinostat dramatically reduced tumor growth in an ABC-DLBCL flank model (U2932) and a systemic double-hit lymphoma model (OCI-Ly18), accompanied by a pronounced increase in survival without significant weight loss or other toxicities. Together, these findings indicate that PLK1/HDAC inhibition warrants attention as a therapeutic strategy in NHL.
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- 2017
21. The IAP antagonist birinapant potentiates bortezomib anti-myeloma activity in vitro and in vivo
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Lora Kramer, Yun Dai, Kanika Sharma, Yun Leng, Maciej Kmieciak, Yu Zhang, Liang Zhou, Steven Grant, Yan Wang, and William Craun
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0301 basic medicine ,Cancer Research ,Indoles ,Antineoplastic Agents ,Mice, SCID ,Inhibitor of apoptosis ,lcsh:RC254-282 ,IAP antagonist ,NF-κB ,Bortezomib ,03 medical and health sciences ,Mice ,0302 clinical medicine ,In vivo ,Multiple myeloma ,Mice, Inbred NOD ,hemic and lymphatic diseases ,medicine ,Animals ,Humans ,FADD ,Molecular Biology ,biology ,lcsh:RC633-647.5 ,Chemistry ,Research ,lcsh:Diseases of the blood and blood-forming organs ,Hematology ,Dipeptides ,lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,medicine.disease ,3. Good health ,Disease Models, Animal ,030104 developmental biology ,Oncology ,Proteasome ,Apoptosis ,030220 oncology & carcinogenesis ,Proteasome inhibitor ,biology.protein ,Cancer research ,medicine.drug - Abstract
Background Mechanisms by which Smac mimetics (SMs) interact with proteasome inhibitors (e.g., bortezomib) are largely unknown, particularly in multiple myeloma (MM), a disease in which bortezomib represents a mainstay of therapy. Methods Interactions between the clinically relevant IAP (inhibitor of apoptosis protein) antagonist birinapant (TL32711) and the proteasome inhibitor bortezomib were investigated in multiple myeloma (MM) cell lines and primary cells, as well as in vivo models. Induction of apoptosis and changes in gene and protein expression were monitored using MM cell lines and confirmed in primary MM cell populations. Genetically modified cells (e.g., exhibiting shRNA knockdown or ectopic expression) were employed to evaluate the functional significance of birinapant/bortezomib-induced changes in protein levels. A MM xenograft model was used to evaluate the in vivo activity of the birinapant/bortezomib regimen. Results Birinapant and bortezomib synergistically induced apoptosis in diverse cell lines, including bortezomib-resistant cells (PS-R). The regimen robustly downregulated cIAP1/2 but not the canonical NF-κB pathway, reflected by p65 phosphorylation and nuclear accumulation. In contrast, the bortezomib/birinapant regimen upregulated TRAF3, downregulated TRAF2, and diminished p52 processing and BCL-XL expression, consistent with disruption of the non-canonical NF-κB pathway. TRAF3 knockdown, ectopic TRAF2, or BCL-XL expression significantly diminished birinapant/bortezomib toxicity. The regimen sharply increased extrinsic apoptotic pathway activation, and cells expressing dominant-negative FADD or caspase-8 displayed markedly reduced birinapant/bortezomib sensitivity. Primary CD138+ (n = 43) and primitive MM populations (CD138−/19+/20+/27+; n = 31) but not normal CD34+ cells exhibited significantly enhanced toxicity with combined treatment (P
- Published
- 2019
22. XPO1 inhibitor combination therapy with bortezomib or carfilzomib induces nuclear localization of IκBα and overcomes acquired proteasome inhibitor resistance in human multiple myeloma
- Author
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Juan A Gomez, Trinayan Kashyap, Yun Dai, Alexis Bauer, Yosef Landesman, Steven Grant, Jana L. Dawson, Daniel M. Sullivan, Kenneth H. Shain, Joel G. Turner, and Mark B. Meads
- Subjects
0301 basic medicine ,Time Factors ,Transcription, Genetic ,Receptors, Cytoplasmic and Nuclear ,Apoptosis ,Mice, SCID ,Pharmacology ,acquired drug resistance ,Bortezomib ,chemistry.chemical_compound ,0302 clinical medicine ,NF-KappaB Inhibitor alpha ,immune system diseases ,Mice, Inbred NOD ,hemic and lymphatic diseases ,Antineoplastic Combined Chemotherapy Protocols ,Multiple myeloma ,Hematology ,carfilzomib ,Protein Stability ,NF-kappa B ,3. Good health ,multiple myeloma ,Gene Expression Regulation, Neoplastic ,Hydrazines ,Oncology ,030220 oncology & carcinogenesis ,XPO1 ,Female ,RNA Interference ,Oligopeptides ,medicine.drug ,Research Paper ,medicine.medical_specialty ,Proteasome Endopeptidase Complex ,Combination therapy ,Active Transport, Cell Nucleus ,Karyopherins ,Transfection ,03 medical and health sciences ,Internal medicine ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Cell Nucleus ,Dose-Response Relationship, Drug ,business.industry ,Cancer ,Triazoles ,medicine.disease ,Carfilzomib ,Xenograft Model Antitumor Assays ,IκBα ,030104 developmental biology ,chemistry ,Drug Resistance, Neoplasm ,Proteolysis ,Cancer research ,Proteasome inhibitor ,business - Abstract
// Joel G. Turner 1 , Trinayan Kashyap 2 , Jana L. Dawson 1 , Juan Gomez 1 , Alexis A. Bauer 1 , Steven Grant 3 , Yun Dai 3 , Kenneth H. Shain 1, 4 , Mark Meads 1 , Yosef Landesman 2 , Daniel M. Sullivan 1, 5 1 Chemical Biology and Molecular Medicine Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA 2 Karyopharm Therapeutics, Natick, MA, USA 3 Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA 4 Department of Malignant Hematology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA 5 Department of Blood & Marrow Transplantation, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA Correspondence to: Daniel M. Sullivan, email: dan.sullivan@moffitt.org Keywords: XPO1, bortezomib, carfilzomib, multiple myeloma, acquired drug resistance Received: July 26, 2016 Accepted: October 12, 2016 Published: October 28, 2016 ABSTRACT Acquired proteasome-inhibitor (PI) resistance is a major obstacle in the treatment of multiple myeloma (MM). We investigated whether the clinical XPO1-inhibitor selinexor, when combined with bortezomib or carfilzomib, could overcome acquired resistance in MM. PI-resistant myeloma cell lines both in vitro and in vivo and refractory myeloma patient biopsies were treated with selinexor/bortezomib or carfilzomib and assayed for apoptosis. Mechanistic studies included NFκB pathway protein expression assays, immunofluorescence microscopy, ImageStream flow-cytometry, and proximity-ligation assays. IκBα knockdown and NFκB activity were measured in selinexor/bortezomib-treated MM cells. We found that selinexor restored sensitivity of PI-resistant MM to bortezomib and carfilzomib. Selinexor/bortezomib treatment inhibited PI-resistant MM tumor growth and increased survival in mice. Myeloma cells from PI-refractory MM patients were sensitized by selinexor to bortezomib and carfilzomib without affecting non-myeloma cells. Immunofluorescence microscopy, Western blot, and ImageStream analyses of MM cells showed increases in total and nuclear IκBα by selinexor/bortezomib. Proximity ligation found increased IκBα-NFκB complexes in treated MM cells. IκBα knockdown abrogated selinexor/bortezomib-induced cytotoxicity in MM cells. Selinexor/bortezomib treatment decreased NFκB transcriptional activity. Selinexor, when used with bortezomib or carfilzomib, has the potential to overcome PI drug resistance in MM. Sensitization may be due to inactivation of the NFκB pathway by IκBα.
- Published
- 2016
23. The NAE inhibitor pevonedistat interacts with the HDAC inhibitor belinostat to target AML cells by disrupting the DDR
- Author
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Kathryn A. Rizzo, Steven Grant, Sri Lakshmi Chalasani, Lawrence F. Povirk, Liang Zhou, Yun Dai, Mohamed Rahmani, Allison Berger, Andrea Ferreira-Gonzalez, Lihong Li, Hui Lin, Catherine I. Dumur, Yun Leng, Shuang Chen, Maciej Kmieciak, and Yu Zhang
- Subjects
0301 basic medicine ,Gene knockdown ,Chemistry ,DNA repair ,Immunology ,Cell Biology ,Hematology ,Pharmacology ,CD38 ,Biochemistry ,Small hairpin RNA ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Pevonedistat ,hemic and lymphatic diseases ,Cancer research ,Histone deacetylase ,CHEK1 ,Belinostat - Abstract
Two classes of novel agents, NEDD8-activating enzyme (NAE) and histone deacetylase (HDAC) inhibitors, have shown single-agent activity in acute myelogenous leukemia (AML)/myelodysplastic syndrome (MDS). Here we examined mechanisms underlying interactions between the NAE inhibitor pevonedistat (MLN4924) and the approved HDAC inhibitor belinostat in AML/MDS cells. MLN4924/belinostat coadministration synergistically induced AML cell apoptosis with or without p53 deficiency or FLT3-internal tandem duplication (ITD), whereas p53 short hairpin RNA (shRNA) knockdown or enforced FLT3-ITD expression significantly sensitized cells to the regimen. MLN4924 blocked belinostat-induced antiapoptotic gene expression through nuclear factor-κB inactivation. Each agent upregulated Bim, and Bim knockdown significantly attenuated apoptosis. Microarrays revealed distinct DNA damage response (DDR) genetic profiles between individual vs combined MLN4924/belinostat exposure. Whereas belinostat abrogated the MLN4924-activated intra-S checkpoint through Chk1 and Wee1 inhibition/downregulation, cotreatment downregulated multiple homologous recombination and nonhomologous end-joining repair proteins, triggering robust double-stranded breaks, chromatin pulverization, and apoptosis. Consistently, Chk1 or Wee1 shRNA knockdown significantly sensitized AML cells to MLN4924. MLN4924/belinostat displayed activity against primary AML or MDS cells, including those carrying next-generation sequencing-defined poor-prognostic cancer hotspot mutations, and CD34(+)/CD38(-)/CD123(+) populations, but not normal CD34(+) progenitors. Finally, combined treatment markedly reduced tumor burden and significantly prolonged animal survival (P < .0001) in AML xenograft models with negligible toxicity, accompanied by pharmacodynamic effects observed in vitro. Collectively, these findings argue that MLN4924 and belinostat interact synergistically by reciprocally disabling the DDR in AML/MDS cells. This strategy warrants further consideration in AML/MDS, particularly in disease with unfavorable genetic aberrations.
- Published
- 2016
24. Abstract B41: Modeling marginal zone lymphomagenesis
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Guanhua Lai, Jolene J. Windle, Alden Chesney, Ian McConnell, Victor Yazbeck, Fadi N Salloum, Roy T. Sabo, Jamal Zweit, Emily Harris, Adolfo G Mauro, Ariel Sindel, Joseph Lownick, Steven Grant, Steven R. Grossman, and Chad Cain
- Subjects
Cancer Research ,biology ,business.industry ,Cancer ,medicine.disease ,Marginal zone ,Malignancy ,Lymphoma ,chemistry.chemical_compound ,medicine.anatomical_structure ,Oncology ,chemistry ,medicine ,Cancer research ,biology.protein ,PTEN ,business ,Lymph node ,PI3K/AKT/mTOR pathway ,Copanlisib - Abstract
Introduction: Indolent B-cell non-Hodgkin’s lymphomas (NHL) represent a heterogeneous group of lymphoproliferative malignancies that remain largely incurable. Marginal zone lymphomas (MZL) are the second most common subtype of indolent NHL and lack a unique cytogenetic identifying abnormality. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as copanlisib and parsaclisib, have shown impressive clinical activity in several indolent lymphomas, including MZL. This further supports the important role of the PI3K pathway in the pathogenesis of this tumor. Therefore, we hypothesized that the PI3K-mTOR pathway is sufficient for driving the pathogenesis of MZL. Methods: In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous global knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1). This led to overactivation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation via weekly physical examinations for several months. Upon tumor detection, the mouse was sacrificed and tumors were sectioned for histologic characterization. In order to generate a more specific model of B cells, and more accurately mimic the underlying human disease, we used the Cre-LoxP system to create the CD19-Cre-PTENfl/fl-LKB1fl/fl. Results: Thirty mice of global KO PTEN+/- LKB1 +/- died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for immunohistochemistry and pathologic characterization. Of the 51 nodes, 61.5% (N=32) showed indolent non-Hodgkin’s lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were of MZL subtype. Compared to wild-type (n=3), the new CD19-Cre-PTENfl/fl-LKB1fl/fl (n=3) showed an overall increase in spleen mass (120 vs. 196 mg, p=0.0564), % B1 cells (4% vs. 59%, p= 0.0075), % MZ cells (5% vs. 30%, p=0.0547), % plasma cells (1% vs. 12%, p=0.0729), and a decrease in % FO cells (80% vs. 12%, p=0.0003) by flow cytometry. Further characterization of the new model is currently under way. Conclusion: Marginal zone lymphoma remains an incurable lymphoma that lacks reliable preclinical models. Our data provide, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and pave the way for future studies understanding the biology of this disease and developing rational therapies for this incurable malignancy. Citation Format: Victor Yazbeck, Ian McConnell, Emily Harris, Joseph Lownick, Ariel Sindel, Roy Sabo, Alden Chesney, Guanhua Lai, Adolfo Mauro, Chad Cain, Fadi Salloum, Steven Grant, Jamal Zweit, Jolene Windle, Steven Grossman. Modeling marginal zone lymphomagenesis [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr B41.
- Published
- 2020
25. R-spondin(g) to syndecan-1 in myeloma
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Steven Grant
- Subjects
0301 basic medicine ,Beta-catenin ,Immunology ,Biochemistry ,Syndecan 1 ,03 medical and health sciences ,0302 clinical medicine ,Mediator ,medicine ,Humans ,Multiple myeloma ,beta Catenin ,Membrane Glycoproteins ,biology ,Cell growth ,Chemistry ,Wnt signaling pathway ,Cell Biology ,Hematology ,Heparin ,medicine.disease ,030104 developmental biology ,Proteoglycan ,030220 oncology & carcinogenesis ,biology.protein ,Cancer research ,Proteoglycans ,Syndecan-1 ,Multiple Myeloma ,medicine.drug - Abstract
In this issue of Blood , Ren et al investigate mechanisms underlying a novel strategy to block multiple myeloma (MM) cell proliferation by targeting the heparin sulfate (HS) proteoglycan syndecan-1 and identify the Wnt/β-catenin pathway as a critical mediator of this approach. If validated, these findings could lead to new therapeutic strategies in MM that may be particularly effective in circumventing microenvironmental forms of resistance in this disorder. 1
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- 2018
26. Corrigendum to 'Adaphostin and bortezomib induce oxidative injury and apoptosis in imatinib mesylate-resistant hematopoietic cells expressing mutant forms of Bcr/Abl' [Leuk. Res. 30 (2006) 1263–1272]
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Paul Dent, Girija Dasmahapatra, Tri K. Nguyen, and Steven Grant
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Cancer Research ,Chemistry ,Bortezomib ,Mutant ,Hematology ,Haematopoiesis ,Imatinib mesylate ,Oncology ,Apoptosis ,medicine ,Cancer research ,Oxidative injury ,Adaphostin ,medicine.drug - Published
- 2019
27. Co-administration of the mTORC1/TORC2 inhibitor INK128 and the Bcl-2/Bcl-xL antagonist ABT-737 kills human myeloid leukemia cells through Mcl-1 down-regulation and AKT inactivation
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Masey Ross, Mandy Mayo Aust, Kathryn A. Rizzo, Rebecca E. Parker, Andrea Ferreira-Gonzalez, Catherine I. Dumur, Mohamed Rahmani, Maciej Kmieciak, Leonid B. Reshko, Elisa Hawkins, and Steven Grant
- Subjects
NPM1 ,Myeloid ,Immunology ,bcl-X Protein ,Down-Regulation ,Mechanistic Target of Rapamycin Complex 2 ,Mice, SCID ,mTORC1 ,Mechanistic Target of Rapamycin Complex 1 ,CD38 ,Biology ,Biochemistry ,mTORC2 ,Piperazines ,Nitrophenols ,Mice ,Mice, Inbred NOD ,hemic and lymphatic diseases ,medicine ,Animals ,Humans ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Benzoxazoles ,Sulfonamides ,U937 cell ,TOR Serine-Threonine Kinases ,Biphenyl Compounds ,Myeloid leukemia ,U937 Cells ,Articles ,Cell Biology ,Hematology ,medicine.disease ,Xenograft Model Antitumor Assays ,Enzyme Activation ,Myeloid Cell Leukemia Sequence 1 Protein ,Leukemia, Myeloid, Acute ,Leukemia ,Haematopoiesis ,Pyrimidines ,medicine.anatomical_structure ,Proto-Oncogene Proteins c-bcl-2 ,Multiprotein Complexes ,Cancer research ,Female ,Nucleophosmin ,Proto-Oncogene Proteins c-akt - Abstract
Acute myelogenous leukemia (AML) is characterized by frequent aberrations of the PI3K/AKT/mTOR axis steming from diverse mechanisms, including FLT3, Ras, and c-KIT mutations, among multiple others. In a previous report, we demonstrated that dual inhibition of the PI3K/mTOR axis and the BH3-mimetic ABT-737, which inhibits both Bcl-2 and Bcl-xL, but not Mcl-1, exhibits potent anti-leukemia activity both in vitro and in vivo (Cancer Res. 2013;73(4):1340-51). It has also been shown that while TORC1 inhibitors such as rapamycin can elicit rebound activation of AKT in various tumor cells, dual inhibition of TORC1/2 potently inhibits AKT activation at both Thr308 and Ser473 sites. In the present studies, we examined whether concurrent inhibition of mTORC1/2 and Bcl-2/Bcl-xL would lead to enhanced anti-leukemia activity in AML cells. Notably, dual tetracycline-inducible Bcl-2/Bcl-xL knockdown markedly sensitized acute myeloid leukemia (AML) cells to the dual TORC1/2 inhibitor INK128 (ChemieTek) in vitro as well as in vivo. Moreover, INK128 co-administered with the Bcl-2/Bcl-xL antagonist ABT-737 (AbbVie) sharply induced cell death in multiple AML cell lines, including TKI-resistant FLT3-ITD mutants as well as primary AML blasts carrying various genetic aberrations e.g., FLT3, IDH2, NPM1, and Kras among others, while exerting minimal toxicity toward normal hematopoietic CD34+ cells. Combined treatment was particularly active against CD34+/CD38-/CD123+ primitive leukemia progenitor cells. The INK128/ABT-737 regimen was also effective in the presence of a protective stromal micro-environment (i.e., co-culture with HS-5 cells), suggesting that this strategy may circumvent the protective effects of bone marrow stromal cells, which are known to play an important role in leukemia cell survival as well as drug resistance. Notably, INK128 was very effective in down-regulating Mcl-1, diminishing AKT and 4EBP1 phosphorylation, and potentiating ABT-737-mediated apoptosis. Furthermore, ectopic expression of Mcl-1 dramatically attenuated INK128/ABT737 lethality, indicating an important functional role for Mcl-1 down-regulation in INK128/ABT-737 interactions. In contrast to INK128, rapamycin increased AML cell AKT phosphorylation, and was largely ineffective in down-regulating Mcl-1, decreasing 4EBP1 phosphorylation, or enhancing ABT-737 lethality. Interestingly, addition of a specific AKT inhibitor to the rapamycin/ABT-737 regimen sharply increased apoptosis in association with pronounced AKT inactivation and Mcl-1 down-regulation, analogous to effects observed with INK128/ABT-737. These findings argue that AKT activation may oppose rapamycin/ABT-737 lethality in AML cells. Immunoprecipitation analysis revealed that combined treatment markedly diminished Bax, Bak, and Bim binding to all major anti-apoptotic Bcl-2 members (Bcl-2/Bcl-xL/Mcl-1), while Bax/Bak shRNA knock-down reduced cell death. Finally, INK128/ABT-737 co-administration sharply attenuated leukemia growth and significantly prolonged survival in a systemic AML xenograft model (P < 0.0001; log-rank test for combined treatment vs either agent alone). In addition, analysis of subcutaneous AML-derived tumors showed significant declines in 4EBP1 phosphorylation and Mcl-1 protein level, consistent with in vitro results. Collectively, these findings demonstrate that co-administration of dual mTORC1/mTORC2 inhibitors and BH3-mimetics exhibits potent anti-leukemic activity in vitro and in vivo, arguing that this strategy warrants attention in AML. They also raise the possibility that dual mTORC1/mTORC2 inhibitors may offer advantages over pure mTORC1 inhibitors in this setting. Disclosures No relevant conflicts of interest to declare.
- Published
- 2015
28. Romidepsin for the treatment of non-Hodgkin’s lymphoma
- Author
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Victor Yazbeck and Steven Grant
- Subjects
Pharmacology ,education.field_of_study ,Antibiotics, Antineoplastic ,biology ,Lymphoma, Non-Hodgkin ,Population ,General Medicine ,Histone acetyltransferase ,medicine.disease ,Lymphoma ,Non-Hodgkin's lymphoma ,Romidepsin ,Histone Deacetylase Inhibitors ,Clinical trial ,Depsipeptides ,medicine ,biology.protein ,Cancer research ,Animals ,Humans ,Pharmacology (medical) ,Histone deacetylase ,Epigenetics ,education ,medicine.drug - Abstract
Patients with relapsed or refractory lymphoma remain a population with unmet medical needs. Histone deacetylase inhibitors (HDACIs) represent a novel class of anticancer drugs currently in development in several malignancies. Inhibition of HDACs leads to acetylation of histone and non-histone proteins, which in turn results in epigenetic modification of gene expression that leads to a plethora of effects, such as cell cycle arrest, apoptosis and inhibition of angiogenesis. Romidepsin is a novel HDACI that has demonstrated preclinical and clinical activity.This review discusses the different HDACs and epigenetic regulation with a particular focus on the preclinical and clinical development of romidepsin in lymphoma. The review of romidepsin includes: the mechanism of action, its synergistic interaction with novel agents, pivotal clinical trials that lead to its US FDA approval in cutaneous T-cell lymphoma and peripheral T-cell lymphoma as well as active combinations currently in clinical trials.Romidepsin is a potent HDACI with clinical activity in T-cell lymphoma where novel agents and combinations are desperately needed. A deeper understanding of the molecular characteristics of this class of agents will allow the design of more potent drugs with improved toxicity profiles and future rational combinations that will expand the indication and benefit from these novel agents.
- Published
- 2015
29. Dual targeting of the thioredoxin and glutathione antioxidant systems in malignant B cells: A novel synergistic therapeutic approach
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Steven H. Bernstein, Yun Dai, Derick R. Peterson, Paul S. Brookes, Sanjay B. Maggirwar, Shannon P. Hilchey, Jolanta Skalska, Michelle Kiebala, Carla Casulo, and Steven Grant
- Subjects
Cancer Research ,Programmed cell death ,Thioredoxin-Disulfide Reductase ,Auranofin ,Antimetabolites ,Cell Survival ,Thioredoxin reductase ,Primary Cell Culture ,Antineoplastic Agents ,Lymphoma, Mantle-Cell ,Biology ,medicine.disease_cause ,Article ,chemistry.chemical_compound ,Thioredoxins ,Cell Line, Tumor ,Genetics ,medicine ,Humans ,Buthionine sulfoximine ,Molecular Targeted Therapy ,Buthionine Sulfoximine ,Molecular Biology ,B-Lymphocytes ,Cell Death ,NF-kappa B ,Drug Synergism ,Cell Biology ,Hematology ,Glutathione ,Gene Expression Regulation, Neoplastic ,Oxidative Stress ,Biochemistry ,chemistry ,Cancer cell ,Cancer research ,Thioredoxin ,Oxidation-Reduction ,Oxidative stress ,Signal Transduction ,medicine.drug - Abstract
B-cell malignancies are a common type of cancer. One approach to cancer therapy is to either increase oxidative stress or inhibit the stress response systems on which cancer cells rely. In this study, we combined nontoxic concentrations of Auranofin (AUR), an inhibitor of the thioredoxin system, with nontoxic concentrations of buthionine-sulfoximine (BSO), a compound that reduces intracellular glutathione levels, and investigated the effect of this drug combination on multiple pathways critical for malignant B-cell survival. Auranofin interacted synergistically with BSO at low concentrations to trigger death in multiple malignant B-cell lines and primary mantle-cell lymphoma cells. Additionally, there was less toxicity toward normal B cells. Low AUR concentrations inhibited thioredoxin reductase (TrxR) activity, an effect significantly increased by BSO cotreatment. Overexpression of TrxR partially reversed AUR+BSO toxicity. Interestingly, the combination of AUR+BSO inhibited nuclear factor κB (NF-κB) signaling. Moreover, synergistic cell death induced by this regimen was attenuated in cells overexpressing NF-κB proteins, arguing for a functional role for NF-κB inhibition in AUR+BSO-mediated cell death. Together, these findings suggest that AUR+BSO synergistically induces malignant B-cell death, a process mediated by dual inhibition of TrxR and NF-κB, and such an approach warrants further investigation in B-cell malignancies.
- Published
- 2015
30. Phase I Trial of Bortezomib (PS-341; NSC 681239) and 'Nonhybrid' (Bolus) Infusion Schedule of Alvocidib (Flavopiridol; NSC 649890) in Patients with Recurrent or Refractory Indolent B-cell Neoplasms
- Author
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Caryn Weir-Wiggins, Wen Wan, John D. Roberts, Maciej Kmieciak, Viswanathan Ramakrishnan, Loveleen Kang, Rachid Baz, Cody J. Peer, Steven Grant, G. David Roodman, E. Brent Perkins, L. Austin Doyle, Prithviraj Bose, Martha D. Wellons, Robert K. Stuart, A. Dimitrios Colevas, Daniel C. Sullivan, Heidi Sankala, Beata Holkova, Ellen Shrader, William D. Figg, Kevin T. Hogan, Connie Honeycutt, Domenico Coppola, Mary Beth Tombes, and Jana L. Dawson
- Subjects
Adult ,Male ,Oncology ,Cancer Research ,medicine.medical_specialty ,Neutropenia ,Pharmacology ,Article ,Drug Administration Schedule ,Bortezomib ,chemistry.chemical_compound ,Piperidines ,Recurrence ,hemic and lymphatic diseases ,Internal medicine ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,Multiple myeloma ,Aged ,Flavonoids ,B-Lymphocytes ,Leukopenia ,business.industry ,Waldenstrom macroglobulinemia ,Middle Aged ,Alvocidib ,medicine.disease ,Boronic Acids ,Combined Modality Therapy ,Lymphoproliferative Disorders ,Regimen ,Treatment Outcome ,chemistry ,Pyrazines ,Retreatment ,Female ,Mantle cell lymphoma ,Drug Monitoring ,medicine.symptom ,business ,medicine.drug - Abstract
Purpose: This phase I study was conducted to determine the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) for the combination of bortezomib and alvocidib in patients with B-cell malignancies (multiple myeloma, indolent lymphoma, Waldenstrom macroglobulinemia, and mantle cell lymphoma). Experimental Design: Patients received bortezomib (intravenous push), followed by alvocidib (1-hour infusion), on days 1, 4, 8, and 11 of a 21-day treatment cycle. Patients experiencing responses or stable disease continued on treatment at the investigator's discretion. A standard 3+3 dose-escalation design was used to identify the MTD based on DLTs, and pharmacokinetic and pharmacodynamic studies were conducted. Results: A total of 44 patients were enrolled, with 39 patients assessed for response. The MTD was established as 1.3 mg/m2 for bortezomib and 40 mg/m2 for alvocidib. The most common hematologic toxicities included leukopenia, lymphopenia, neutropenia, and thrombocytopenia. The most common nonhematologic toxicities included diarrhea, fatigue, and sensory neuropathy. Three complete remissions (8%) and 10 partial remissions (26%) were observed for a total response rate of 33%. Pharmacokinetic findings with the current dosing regimen were consistent with the comparable literature and the hybrid dosing regimen. Pharmacodynamic study results did not correlate with clinical responses. Conclusions: The combination of bortezomib and alvocidib is tolerable, and an MTD has been established for this schedule. The regimen appears to be efficacious in patients with relapsed/refractory multiple myeloma or indolent non-Hodgkin lymphoma. As the nonhybrid regimen is less cumbersome than the previous hybrid dosing schedule regimen, the current schedule is recommended for successor studies. Clin Cancer Res; 20(22); 5652–62. ©2014 AACR.
- Published
- 2014
31. A phase 1 study of bortezomib and romidepsin in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma, indolent B-cell lymphoma, peripheral T-cell lymphoma, or cutaneous T-cell lymphoma
- Author
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Prithviraj Bose, Thomas C. Shea, Amanda Garnett Singh, Heidi Sankala, Steven Grant, Victor Yazbeck, John D. Roberts, Beata Holkova, Kevin T. Hogan, Shuo Ma, Caryn Weir-Wiggins, Amy S. Kimball, Ellen Shrader, Sarah Conine, Wen Wan, Maciej Kmieciak, and Mary Beth Tombes
- Subjects
0301 basic medicine ,Oncology ,Male ,Cancer Research ,medicine.medical_specialty ,Pathology ,Maximum Tolerated Dose ,Chronic lymphocytic leukemia ,Article ,Romidepsin ,Bortezomib ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,hemic and lymphatic diseases ,Depsipeptides ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Humans ,B-cell lymphoma ,neoplasms ,business.industry ,Cutaneous T-cell lymphoma ,Lymphoma, T-Cell, Peripheral ,Hematology ,medicine.disease ,Combined Modality Therapy ,Leukemia, Lymphocytic, Chronic, B-Cell ,Peripheral T-cell lymphoma ,Lymphoma ,Lymphoma, T-Cell, Cutaneous ,030104 developmental biology ,Treatment Outcome ,030220 oncology & carcinogenesis ,Female ,business ,Progressive disease ,medicine.drug - Abstract
A phase 1 study was conducted to determine the dose-limiting toxicities and maximum tolerated dose (MTD) for bortezomib followed by romidepsin on days 1, 8, and 15 in patients with relapsed/refractory CLL/SLL or B- or T-cell lymphoma. Eighteen treated patients were evaluable for response. The MTD was 1.3 mg/m2 bortezomib and 10 mg/m2 romidepsin; median treatment duration was 3 cycles at this dose. The dose-limiting toxicities were grade 3 fatigue, vomiting, and chills. Two patients had partial responses, one lasting >2 years, 8 had stable disease, and 8 had progressive disease. The median duration of stable disease was 3.5 cycles. Correlative studies examining expression of NF-κB, XIAP, Bcl-xL, and Bim yielded variable results. The safety profile was consistent with that reported for single-agent bortezomib and romidepsin. This regimen has modest activity in heavily pre-treated patients with relapsed/refractory CLL or B- or T-cell lymphoma. NCT00963274.
- Published
- 2017
32. A Bim-targeting strategy overcomes adaptive bortezomib resistance in myeloma through a novel link between autophagy and apoptosis
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Xin Yan Pei, Yun Dai, Shuang Chen, Robert Z. Orlowski, Liang Zhou, Yun Leng, Richard J. Jones, Steven Grant, Maciej Kmieciak, Yu Zhang, and Hui Lin
- Subjects
cells ,Fluorescent Antibody Technique ,Apoptosis ,Mice, SCID ,Hydroxamic Acids ,Biochemistry ,Bortezomib ,Small hairpin RNA ,immune system diseases ,Mice, Inbred NOD ,hemic and lymphatic diseases ,Antineoplastic Combined Chemotherapy Protocols ,Cells, Cultured ,Mice, Knockout ,Gene knockdown ,Lymphoid Neoplasia ,Bcl-2-Like Protein 11 ,hemic and immune systems ,Hematology ,Boronic Acids ,Tumor Burden ,Pyrazines ,RNA Interference ,biological phenomena, cell phenomena, and immunity ,Multiple Myeloma ,medicine.drug ,Immunoblotting ,Immunology ,Biology ,Downregulation and upregulation ,Cell Line, Tumor ,Proto-Oncogene Proteins ,Autophagy ,medicine ,Animals ,Humans ,neoplasms ,Membrane Proteins ,Cell Biology ,Xenograft Model Antitumor Assays ,Molecular biology ,Histone Deacetylase Inhibitors ,Drug Resistance, Neoplasm ,Cell culture ,Cancer research ,Histone deacetylase ,Apoptosis Regulatory Proteins - Abstract
Bim contributes to resistance to various standard and novel agents. Here we demonstrate that Bim plays a functional role in bortezomib resistance in multiple myeloma (MM) cells and that targeting Bim by combining histone deacetylase inhibitors (HDACIs) with BH3 mimetics (eg, ABT-737) overcomes bortezomib resistance. BH3-only protein profiling revealed high Bim levels (Bim(hi)) in most MM cell lines and primary CD138(+) MM samples. Whereas short hairpin RNA Bim knockdown conferred bortezomib resistance in Bim(hi) cells, adaptive bortezomib-resistant cells displayed marked Bim downregulation. HDACI upregulated Bim and, when combined with ABT-737, which released Bim from Bcl-2/Bcl-xL, potently killed bortezomib-resistant cells. These events were correlated with Bim-associated autophagy attenuation, whereas Bim knockdown sharply increased autophagy in Bim(hi) cells. In Bim(low) cells, autophagy disruption by chloroquine (CQ) was required for HDACI/ABT-737 to induce Bim expression and lethality. CQ also further enhanced HDACI/ABT-737 lethality in bortezomib-resistant cells. Finally, HDACI failed to diminish autophagy or potentiate ABT-737-induced apoptosis in bim(-/-) mouse embryonic fibroblasts. Thus, Bim deficiency represents a novel mechanism of adaptive bortezomib resistance in MM cells, and Bim-targeting strategies combining HDACIs (which upregulate Bim) and BH3 mimetics (which unleash Bim from antiapoptotic proteins) overcomes such resistance, in part by disabling cytoprotective autophagy.
- Published
- 2014
33. A regimen combining the Wee1 inhibitor AZD1775 with HDAC inhibitors targets human acute myeloid leukemia cells harboring various genetic mutations
- Author
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Yun Dai, Kathryn A. Rizzo, Steven Grant, Maciej Kmieciak, Catherine I. Dumur, Yu Zhang, Liang Zhou, Andrea Ferreira-Gonzalez, Shuang Chen, Yun Leng, and Hui Lin
- Subjects
Cancer Research ,Cell cycle checkpoint ,Apoptosis ,Cell Cycle Proteins ,Hydroxamic Acids ,Mice ,checkpoint ,AML ,Myeloid Cells ,Phosphorylation ,WEE1 Inhibitor AZD1775 ,Vorinostat ,Gene Expression Regulation, Leukemic ,Nuclear Proteins ,Myeloid leukemia ,Drug Synergism ,Hematology ,Protein-Tyrosine Kinases ,Cell cycle ,cdc2/Cdk1 ,Cyclin-Dependent Kinases ,3. Good health ,Leukemia, Myeloid, Acute ,Leukemia ,Oncology ,Drug Therapy, Combination ,Signal Transduction ,medicine.drug ,Primary Cell Culture ,Wee1 inhibitor ,Chk1 ,DNA Fragmentation ,Biology ,Article ,HDAC inhibitor ,CDC2 Protein Kinase ,medicine ,Animals ,Humans ,CHEK1 ,Protein Kinase Inhibitors ,Cell Cycle Checkpoints ,medicine.disease ,Survival Analysis ,Xenograft Model Antitumor Assays ,Histone Deacetylase Inhibitors ,fms-Like Tyrosine Kinase 3 ,Checkpoint Kinase 1 ,Fms-Like Tyrosine Kinase 3 ,Cancer research ,Tumor Suppressor Protein p53 ,Protein Kinases - Abstract
AZD1775 targets the cell cycle checkpoint kinase Wee1 and potentiates genotoxic agent cytotoxicity through p53-dependent or -independent mechanisms. Here, we report that AZD1775 interacted synergistically with histone deacetylase inhibitors (HDACIs, for example, Vorinostat), which interrupt the DNA damage response, to kill p53-wild type (wt) or -deficient as well as FLT3-ITD leukemia cells in association with pronounced Wee1 inhibition and diminished cdc2/Cdk1 Y15 phosphorylation. Similarly, Wee1 shRNA knockdown significantly sensitized cells to HDACIs. Although AZD1775 induced Chk1 activation, reflected by markedly increased Chk1 S296/S317/S345 phosphorylation leading to inhibitory T14 phosphorylation of cdc2/Cdk1, these compensatory responses were sharply abrogated by HDACIs. This was accompanied by premature mitotic entry, multiple mitotic abnormalities and accumulation of early S-phase cells displaying increased newly replicated DNA, culminating in robust DNA damage and apoptosis. The regimen was active against patient-derived acute myelogenous leukemia (AML) cells harboring either wt or mutant p53 and various next-generation sequencing-defined mutations. Primitive CD34(+)/CD123(+)/CD38(-) populations enriched for leukemia-initiating progenitors, but not normal CD34(+) hematopoietic cells, were highly susceptible to this regimen. Finally, combining AZD1775 with Vorinostat in AML murine xenografts significantly reduced tumor burden and prolonged animal survival. A strategy combining Wee1 with HDACI inhibition warrants further investigation in AML with poor prognostic genetic aberrations.
- Published
- 2014
34. Rational combination of dual PI3K/mTOR blockade and Bcl-2/-xL inhibition in AML
- Author
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Pankit Vachhani, Mohamed Rahmani, Prithviraj Bose, and Steven Grant
- Subjects
Physiology ,bcl-X Protein ,Bcl-xL ,Biology ,Piperazines ,Nitrophenols ,Antineoplastic Combined Chemotherapy Protocols ,Genetics ,medicine ,Animals ,Humans ,Protein Kinase Inhibitors ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Phosphoinositide-3 Kinase Inhibitors ,Sirolimus ,Sulfonamides ,Kinase ,TOR Serine-Threonine Kinases ,Biphenyl Compounds ,RPTOR ,General Interest ,Leukemia, Myeloid, Acute ,Proto-Oncogene Proteins c-bcl-2 ,Cancer research ,biology.protein ,Signal transduction ,Signal Transduction ,medicine.drug - Abstract
Acute myeloid leukemia (AML) continues to represent an area of critical unmet need with respect to new and effective targeted therapies. The Bcl-2 family of pro- and antiapoptotic proteins stands at the crossroads of cellular survival and death, and the expression of and interactions between these proteins determine tumor cell fate. Malignant cells, which are often primed for apoptosis, are particularly vulnerable to the simultaneous disruption of cooperative survival signaling pathways. Indeed, the single agent activity of agents such as mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase kinase (MEK) inhibitors in AML has been modest. Much work in recent years has focused on strategies to enhance the therapeutic potential of the bona fide BH3-mimetic, ABT-737, which inhibits B-cell lymphoma 2 (Bcl-2) and Bcl-xL. Most of these strategies target Mcl-1, an antiapoptotic protein not inhibited by ABT-737. The phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR and Ras/Raf/MEK/ERK signaling pathways are central to the growth, proliferation, and survival of AML cells, and there is much interest currently in pharmacologically interrupting these pathways. Dual inhibitors of PI3K and mTOR overcome some intrinsic disadvantages of rapamycin and its derivatives, which selectively inhibit mTOR. In this review, we discuss why combining dual PI3K/mTOR blockade with inhibition of Bcl-2 and Bcl-xL, by virtue of allowing coordinate inhibition of three mutually synergistic pathways in AML cells, may be a particularly attractive therapeutic strategy in AML, the success of which may be predicted for by basal Akt activation.
- Published
- 2014
35. Pazopanib and HDAC inhibitors interact to kill sarcoma cells
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Hossein A. Hamed, Paul Dent, Steven Grant, Seyedmehrad Tavallai, and Andrew Poklepovic
- Subjects
Cancer Research ,Indazoles ,Mice, Nude ,Antineoplastic Agents ,Biology ,Pharmacology ,Autophagy-Related Protein 5 ,Pazopanib ,Cell Line, Tumor ,Autophagy ,medicine ,Animals ,FADD ,Protein kinase B ,Vorinostat ,PI3K/AKT/mTOR pathway ,Sulfonamides ,Gene knockdown ,Valproic Acid ,Membrane Proteins ,Drug Synergism ,Sarcoma ,Receptors, Death Domain ,medicine.disease ,Histone Deacetylase Inhibitors ,Pyrimidines ,Oncology ,Gene Knockdown Techniques ,Cancer research ,biology.protein ,Molecular Medicine ,Beclin-1 ,Female ,Histone deacetylase ,Apoptosis Regulatory Proteins ,Microtubule-Associated Proteins ,Research Paper ,Signal Transduction ,medicine.drug - Abstract
The present studies were to determine whether the multi-kinase inhibitor pazopanib interacted with histone deacetylase inhibitors (HDACI: valproate, vorinostat) to kill sarcoma cells. In multiple sarcoma cell lines, at clinically achievable doses, pazopanib and HDACI interacted in an additive to greater than additive fashion to cause tumor cell death. The drug combination increased the numbers of LC3-GFP and LC3-RFP vesicles. Knockdown of Beclin1 or ATG5 significantly suppressed drug combination lethality. Expression of c-FLIP-s, and to a lesser extent BCL-XL or dominant negative caspase 9 reduced drug combination toxicity; knock down of FADD or CD95 was protective. Expression of both activated AKT and activated MEK1 was required to strongly suppress drug combination lethality. The drug combination inactivated mTOR and expression of activated mTOR strongly suppressed drug combination lethality. Treatment of animals carrying sarcoma tumors with pazopanib and valproate resulted in a greater than additive reduction in tumor volume compared with either drug individually. As both pazopanib and HDACIs are FDA-approved agents, our data argue for further determination as to whether this drug combination is a useful sarcoma therapy in the clinic.
- Published
- 2014
36. Editor's Note: Regulation of OSU-03012 Toxicity by ER Stress Proteins and ER Stress–Inducing Drugs
- Author
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Paul Dent, Andrew Poklepovic, Jane L. Roberts, Laurence Booth, Nichola Cruickshanks, and Steven Grant
- Subjects
0301 basic medicine ,Cancer Research ,business.industry ,Published Erratum ,Mistake ,OSU-03012 ,Bioinformatics ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,0302 clinical medicine ,Oncology ,chemistry ,030220 oncology & carcinogenesis ,Toxicity ,Unfolded protein response ,Medicine ,business - Abstract
The editors are publishing this note to alert readers to a concern about [this article][1] ([1][2]). The authors informed the journal that there was a mistake in Fig. 4D. Specifically, the XBP-1 and GAPDH knock down panel for GBM6 was duplicated and mislabeled for GBM5. After a review of the
- Published
- 2019
37. Abstract 4634: Mouse model for nodal marginal zone lymphoma
- Author
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Daniel H. Conrad, Joseph C. Lownik, Steven R. Grossman, Victor Yazbeck, Roy T. Sabo, Ian McConnell, Jolene J. Windle, Adolfo G Mauro, Guanhua Lai, Steven Grant, Jamal Zweit, Rebecca K. Martin, Alden Chesney, and Ariel Sindel
- Subjects
Cancer Research ,Cancer ,Biology ,Malignancy ,medicine.disease ,Lymphoma ,chemistry.chemical_compound ,Oncology ,chemistry ,medicine ,biology.protein ,Cancer research ,PTEN ,Tensin ,Idelalisib ,PI3K/AKT/mTOR pathway ,Copanlisib - Abstract
Introduction: Indolent B-Cell Non-Hodgkin’s Lymphoma (i-NHL) represents a heterogeneous group of lymphoproliferative malignancies, encompassing 40% of NHL, that remains largely incurable. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as idelalisib and copanlisib, have shown impressive clinical activity in several indolent lymphomas including marginal zone lymphoma (MZL). This further supports the important role of the PI3K pathway in these tumors. Methods We generated a genetically engineered mouse model carrying heterozygous knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1), leading to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation by at least weekly physical examinations for several months. Upon tumor detection, tumor size was recorded weekly using calipers, with an experimental endpoint of 15-20mm in any dimension. One half of the tumor was immediately preserved in a 4% paraformaldehyde solution and prepared for sectioning, H&E and immunohistochemical staining. Results: Thirty mice died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for IHC and pathological identification. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin’s Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were Marginal Zone subtype. In order to generate a more specific model of B cells, we used the Cre/LoxP system with CD19-Cre. We detected an increase in the average portion of MZL B cells in the spleen of the homozygous mice compared to wild type (38.3% vs 4.9%, p=0.0216). Conclusion: Nodal marginal zone lymphoma remains an incurable indolent lymphoma that lacks preclinical models. As novel agents become available, it is important to have a better understanding of the underlying pathogenesis of this malignancy and be able to model it in an immunocompetent mouse with a preserved microenvironment. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of nodal marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Note: This abstract was not presented at the meeting. Citation Format: Victor Yazbeck, Ian McConnell, Joseph Lownik, Ariel Sindel, Roy Sabo, Alden Chesney, Guanhua Lai, Adolfo Mauro, Jamal Zweit, Rebecca Martin, Daniel Conrad, Steven Grant, Jolene Windle, Steven Grossman. Mouse model for nodal marginal zone lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4634.
- Published
- 2019
38. Retraction: Carfilzomib Interacts Synergistically with Histone Deacetylase Inhibitors in Mantle Cell Lymphoma Cells In Vitro and In Vivo
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Girija Dasmahapatra, Dmitry Lembersky, Minkyeong P. Son, Elisa Attkisson, Paul Dent, Richard I. Fisher, Jonathan W. Friedberg, and Steven Grant
- Subjects
Cancer Research ,Oncology - Published
- 2019
39. Retraction: In Vitro and In Vivo Interactions between the HDAC6 Inhibitor Ricolinostat (ACY1215) and the Irreversible Proteasome Inhibitor Carfilzomib in Non-Hodgkin Lymphoma Cells
- Author
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Girija Dasmahapatra, Hiral Patel, Johnathan Friedberg, Steven N. Quayle, Simon S. Jones, and Steven Grant
- Subjects
Cancer Research ,Oncology - Published
- 2019
40. Retraction: Obatoclax Interacts Synergistically with the Irreversible Proteasome Inhibitor Carfilzomib in GC- and ABC-DLBCL Cells In Vitro and In Vivo
- Author
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Girija Dasmahapatra, Dmitry Lembersky, Minkyeong P. Son, Hiral Patel, Derick Peterson, Elisa Attkisson, Richard I. Fisher, Jonathan W. Friedberg, Paul Dent, and Steven Grant
- Subjects
Cancer Research ,Oncology - Published
- 2019
41. HDAC inhibitors enhance the lethality of low dose salinomycin in parental and stem-like GBM cells
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Paul Dent, Jane L. Roberts, Nichola Cruickshanks, Steven Grant, Thomas Ridder, Adam Conley, Laurence Booth, and Andrew Poklepovic
- Subjects
Cancer Research ,Antineoplastic Agents ,Apoptosis ,Breast Neoplasms ,Caspase 3 ,P70-S6 Kinase 1 ,Pharmacology ,Biology ,Hydroxamic Acids ,Caspase 8 ,Necrosis ,chemistry.chemical_compound ,Cell Line, Tumor ,Autophagy ,Humans ,PI3K/AKT/mTOR pathway ,Salinomycin ,Pyrans ,Vorinostat ,Valproic Acid ,Drug Synergism ,Fas receptor ,Histone Deacetylase Inhibitors ,Oncology ,chemistry ,Neoplastic Stem Cells ,Molecular Medicine ,Female ,Stem cell ,Glioblastoma ,Research Paper - Abstract
The present studies determined whether the antibiotic salinomycin interacted with HDAC inhibitors to kill primary human GBM cells. Regardless of PTEN, ERBB1, or p53 mutational status salinomycin interacted with HDAC inhibitors in a synergistic fashion to kill GBM cells. Inhibition of CD95/Caspase 8 or of CD95/RIP-1/AIF signaling suppressed killing by the drug combination. Salinomycin increased the levels of autophagosomes that correlated with increased p62 and LC3II levels; valproate co-treatment correlated with reduced LC3II and p62 expression, and increased caspase 3 cleavage. Molecular inhibition of autophagosome formation was protective against drug exposure. The drug combination enhanced eIF2α phosphorylation and decreased expression of MCL-1 and phosphorylation of mTOR and p70 S6K. Activation of p70 S6K or mTOR promoted cell survival in the face of combined drug exposure. Overexpression of BCL-XL or c-FLIP-s was protective. Collectively our data demonstrate that the lethality of low nanomolar concentrations of salinomycin are enhanced by HDAC inhibitors in GBM cells and that increased death receptor signaling together with reduced mitochondrial function are causal in the combinatorial drug necro-apoptotic killing effect.
- Published
- 2013
42. Role of the PI3K Pathway in the Pathogenesis of Marginal Zone Lymphoma
- Author
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Taha Al-Juhaishi, Mohamed Rahmani, Guanhua Lai, Steven R. Grossman, Ian McConnell, Steven Grant, Adolfo G Mauro, Roy T. Sabo, Victor Yazbeck, Jolene J. Windle, Alden Chesney, Ariel Sindel, and Jamal Zweit
- Subjects
business.industry ,Immunology ,Large-cell lymphoma ,Follicular lymphoma ,Cell Biology ,Hematology ,medicine.disease ,Marginal zone ,Biochemistry ,Lymphoma ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,030220 oncology & carcinogenesis ,medicine ,Cancer research ,Marginal zone B-cell lymphoma ,Idelalisib ,business ,Diffuse large B-cell lymphoma ,030215 immunology ,Copanlisib - Abstract
Introduction There are roughly 75,000 new cases of Non-Hodgkin's Lymphoma every year, representing almost 5% of all new cancer diagnoses. Indolent B-Cell Non-Hodgkin's Lymphoma (i-NHL) represents a heterogeneous group of lymphoproliferative malignancies, encompassing 40% of NHL, that remains largely incurable. Follicular lymphoma and marginal zone lymphoma (MZL) are the two most common subtypes of i-NHL. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as idelalisib and copanlisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in these tumors. Therefore, we hypothesized that the PI3K-mTOR (mammalian target of rapamycin) pathway is sufficient for driving the pathogenesis of marginal zone lymphomas. Methods In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1), leading to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation by at least weekly physical examinations for several months. Upon tumor detection, tumor size was recorded weekly using calipers, with an experimental endpoint of 15-20mm in any dimension. Upon reaching this endpoint, or if the surrounding area became necrotic/ulcerated, if the mouse's physical/behavioral condition deteriorated, or if there were any adverse conditions warranting mouse sacrifice, the mouse was euthanized and any existing tumors and any other tissues of interest were harvested. One half of the tumor was immediately preserved in a 4% paraformaldehyde solution and prepared for sectioning, H&E and immunohistochemical staining, with CD3 (T-cell marker), and PAX-5 (B-cell marker). The 2nd half of the tumor was processed using a "stomacher" machine to dissociate the tumor cells, which were then counted and frozen in accordance with cryopreservation guidelines suggested by the American Type Culture Collection (ATCC). Results We generated an initial cohort of 49 Pten+/-/Lkb1+/- mice. Among all mice, the average survival time was 6 months. Thirty mice died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either lymphadenopathy or splenomegaly (Figure 1). By Kaplan-Meier analysis, we see a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for IHC and pathological identification. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were Marginal Zone subtype (Figure 2), except one case that was suspicious for follicular lymphoma. We have not identified any large cell lymphoma or development of other malignancies. Discussion Marginal zone lymphoma remains an incurable indolent lymphoma that lacks preclinical models. As novel agents become available, it is important to have a better understanding of the underlying pathogenesis of this malignancy and be able to model it in a immunocompetent mouse with a preserved microenvironment. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures No relevant conflicts of interest to declare.
- Published
- 2018
43. BCL2L11/Bim as a dual-agent regulating autophagy and apoptosis in drug resistance
- Author
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Yun Dai and Steven Grant
- Subjects
Bcl-2-Like Protein 11 ,medicine.medical_treatment ,Autophagy ,Drug Resistance ,bcl-X Protein ,Membrane Proteins ,Antineoplastic Agents ,Apoptosis ,Cell Biology ,Drug resistance ,Biology ,Autophagic Puncta ,Targeted therapy ,Cell biology ,BCL2L11 ,Proto-Oncogene Proteins ,Cancer research ,medicine ,Humans ,biological phenomena, cell phenomena, and immunity ,Apoptosis Regulatory Proteins ,Molecular Biology - Abstract
A variety of anticancer agents employed in standard chemotherapy or novel targeted therapy induce autophagy. A cytoprotective autophagic response often counteracts apoptosis triggered by such agents, potentially contributing to acquired drug-resistance. It is recognized that autophagy and apoptosis share molecular regulatory mechanisms primarily governed by multidomain anti-apoptotic members (e.g., BCL2/Bcl(-)2 and BCL2L1/Bcl(-)xL) of the BCL2 family. However, the role of pro-apoptotic BH3-only proteins (e.g.,, BCL2L11/Bim), another class of BCL2 family proteins that critically determine therapeutic responses, in autophagy regulation remains largely unexplored, particularly with respect to mechanisms of acquired drug resistance.
- Published
- 2015
44. Histone deacetylase inhibitors restore toxic BH3 domain protein expression in anoikis-resistant mammary and brain cancer stem cells, thereby enhancing the response to anti-ERBB1/ERBB2 therapy
- Author
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Hossein A. Hamed, Laurence Booth, Seyedmehrad Tavallai, Andrew Poklepovic, Nichola Cruickshanks, Jahangir Syed, Gangadharan B. Sajithlal, Paul Dent, and Steven Grant
- Subjects
Cancer Research ,Indoles ,Receptor, ErbB-2 ,Cell ,Gene Expression ,Epigenesis, Genetic ,necrosis ,Mice ,0302 clinical medicine ,anoikis ,Anoikis ,RNA, Small Interfering ,ERBB1 ,bcl-2-Associated X Protein ,BH3 domain ,0303 health sciences ,biology ,Brain Neoplasms ,3. Good health ,ErbB Receptors ,Gene Expression Regulation, Neoplastic ,bcl-2 Homologous Antagonist-Killer Protein ,Cell killing ,medicine.anatomical_structure ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Neoplastic Stem Cells ,Molecular Medicine ,Female ,Stem cell ,signaling ,Bcl-2 Homologous Antagonist-Killer Protein ,Research Paper ,autophagy ,tumor ,Programmed cell death ,Antineoplastic Agents, Hormonal ,Cell Survival ,NOXA ,bcl-X Protein ,Mice, Nude ,Breast Neoplasms ,03 medical and health sciences ,Bcl-2-associated X protein ,Proto-Oncogene Proteins ,medicine ,Animals ,Humans ,Pyrroles ,030304 developmental biology ,Pharmacology ,Valproic Acid ,BAK ,Lapatinib ,Xenograft Model Antitumor Assays ,Molecular biology ,Histone Deacetylase Inhibitors ,Drug Resistance, Neoplasm ,Quinazolines ,biology.protein ,Cancer research ,Myeloid Cell Leukemia Sequence 1 Protein ,Histone deacetylase ,MCL-1 ,Apoptosis Regulatory Proteins - Abstract
The present studies focused on defining the mechanisms by which anoikis-resistant (AR) mammary carcinoma cells can be reverted to a therapy-sensitive phenotype. AR mammary carcinoma cells had reduced expression of the toxic BH3 domain proteins BAX, BAK, NOXA, and PUMA. In AR cells expression of the protective BCL-2 family proteins BCL-XL and MCL-1 was increased. AR cells were resistant to cell killing by multiple anti-tumor cell therapies, including ERBB1/2 inhibitor + MCL-1 inhibitor treatment, and had a reduced autophagic flux response to these therapies, despite similarly exhibiting increased levels of LC3II processing. Knockdown of MCL-1 and BCL-XL caused necro-apoptosis in AR cells to a greater extent than in parental cells. Pre-treatment of anoikis-resistant cells with histone deacetylase inhibitors (HDACIs) for 24 h increased the levels of toxic BH3 domain proteins, reduced MCL-1 levels, and restored/re-sensitized the cell death response of AR tumor cells to multiple toxic therapies. In vivo, pre-treatment of AR breast tumors in the brain with valproate restored the chemo-sensitivity of the tumors and prolonged animal survival. These data argue that one mechanism to enhance the anti-tumor effect of chemotherapy could be HDACI pre-treatment.
- Published
- 2013
45. PLK1 Inhibitors Synergistically Potentiate HDAC Inhibitor Lethality in Imatinib Mesylate–Sensitive or –Resistant BCR/ABL+ Leukemia Cells In Vitro and In Vivo
- Author
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Tri K. Nguyen, Elisa Attkisson, Steven Grant, Girija Dasmahapatra, and Hiral Patel
- Subjects
Cancer Research ,Cell Survival ,Fusion Proteins, bcr-abl ,Antigens, CD34 ,Cell Cycle Proteins ,Protein Serine-Threonine Kinases ,Biology ,Histone Deacetylases ,Piperazines ,Article ,Mice ,Cell Line, Tumor ,Proto-Oncogene Proteins ,hemic and lymphatic diseases ,medicine ,Animals ,Humans ,Protein Kinase Inhibitors ,Vorinostat ,Leukemia ,ABL ,Cell Cycle ,breakpoint cluster region ,Drug Synergism ,Imatinib ,Transfection ,Hematopoietic Stem Cells ,medicine.disease ,Xenograft Model Antitumor Assays ,Histone Deacetylase Inhibitors ,Pyrimidines ,Imatinib mesylate ,Oncology ,Drug Resistance, Neoplasm ,Gene Knockdown Techniques ,Benzamides ,Imatinib Mesylate ,Cancer research ,K562 Cells ,Reactive Oxygen Species ,DNA Damage ,medicine.drug ,K562 cells - Abstract
Purpose: To determine whether Polo-like kinase 1 (PLK1) inhibitors (e.g., BI2536) and histone deacetylase (HDAC) inhibitors (e.g., vorinostat) interact synergistically in the BCR/ABL+ leukemia cells sensitive or resistant to imatinib mesylate (IM) in vitro and in vivo. Experimental Design: K562 and LAMA84 cells sensitive or resistant to imatinib mesylate and primary CML cells were exposed to BI2536 and vorinostat. Effects on cell viability and signaling pathways were determined using flow cytometry, Western blotting, and gene transfection. K562 and BV173/E255K animal models were used to test in vivo efficacy. Results: Cotreatment with BI2536 and vorinostat synergistically induced cell death in parental or imatinib mesylate–resistant BCR/ABL+ cells and primary CD34+ bone marrow cells but was minimally toxic to normal cells. BI2536/vorinostat cotreatment triggered pronounced mitochondrial dysfunction, inhibition of p-BCR/ABL, caspase activation, PARP cleavage, reactive oxygen species (ROS) generation, and DNA damage (manifest by increased expression of γH2A.X, p-ATM, p-ATR), events attenuated by the antioxidant TBAP. PLK1 short hairpin RNA (shRNA) knockdown significantly increased HDACI lethality, whereas HDAC1–3 shRNA knockdown reciprocally increased BI2536-induced apoptosis. Genetic interruption of the DNA damage linker H1.2 partially but significantly reduced PLK1/HDAC inhibitor–mediated cell death, suggesting a functional role for DNA damage in lethality. Finally, BI2536/vorinostat cotreatment dramatically reduced tumor growth in both subcutaneous and systemic BCR/ABL+ leukemia xenograft models and significantly enhanced animal survival. Conclusions: These findings suggest that concomitant PLK1 and HDAC inhibition is active against imatinib mesylate–sensitive or refractory CML and ALL cells both in vitro and in vivo and that this strategy warrants further evaluation in the setting of BCR/ABL+ leukemias. Clin Cancer Res; 19(2); 404–14. ©2012 AACR.
- Published
- 2013
46. Atg7 in AML: a double-edged sword?
- Author
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Steven Grant
- Subjects
0301 basic medicine ,Autophagy-Related Proteins ,Myeloid Neoplasia ,business.industry ,Immunology ,Autophagy ,Myeloid leukemia ,Cell Biology ,Hematology ,Biochemistry ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,hemic and lymphatic diseases ,030220 oncology & carcinogenesis ,Cancer research ,Medicine ,business - Abstract
In this issue of Blood, Piya et al have identified the autophagy-related E1 ligase Atg7, a critical autophagy component associated with unfavorable outcomes in acute myeloid leukemia (AML), as a potential target in this disease.1 If validated, this study could provide a foundation for disrupting Atg7 in AML therapy.
- Published
- 2016
47. A focus on the preclinical development and clinical status of the histone deacetylase inhibitor, romidepsin (depsipeptide, Istodax®)
- Author
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Maria E Araujo, Yun Dai, Richard Piekarz, Steven Grant, Becki Lee, Simon J. Harrison, Mark Bishton, H. Miles Prince, Ricky W. Johnstone, and Susan E. Bates
- Subjects
Cancer Research ,medicine.drug_class ,Drug Evaluation, Preclinical ,Antineoplastic Agents ,Apoptosis ,Biology ,Pharmacology ,Histone Deacetylase 6 ,Article ,Histone Deacetylases ,Romidepsin ,Bortezomib ,Cell Line, Tumor ,Depsipeptides ,Autophagy ,Genetics ,medicine ,Animals ,Humans ,Depsipeptide ,Clinical Trials as Topic ,Neovascularization, Pathologic ,Histone deacetylase inhibitor ,Acetylation ,Drug Synergism ,HDAC6 ,Cell cycle ,Hypoxia-Inducible Factor 1, alpha Subunit ,Boronic Acids ,Lymphoma, T-Cell, Cutaneous ,Histone Deacetylase Inhibitors ,Pyrazines ,Cancer research ,Histone deacetylase ,Proteasome Inhibitors ,medicine.drug - Abstract
Romidepsin (Istodax®, depsipeptide, FR901228, FK228, NSC 630176) is a cyclic peptide, broad-spectrum, potent histone deacetylase inhibitor, with activity mainly against class I histone deacetylase enzymes. In this article, we give an overview of the putative modes of action, such as effects on gene expression, cell cycle regulation, apoptosis induction, DNA repair, protein acetylation and induction of autophagy. Romidepsin has mainly been developed as a therapy for hematologic malignancies and is approved by the US FDA for the treatment of cutaneous T-cell lymphomas. This report outlines the laboratory and clinical development of the compound as a single agent that has more recently been evaluated in combination with other anticancer therapeutics, such as proteasome inhibitors.
- Published
- 2012
48. Lapatinib and Obatoclax Kill Breast Cancer Cells through Reactive Oxygen Species-Dependent Endoplasmic Reticulum Stress
- Author
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Hossein A. Hamed, Laurence Booth, Yong Tang, Steven Grant, Paul Dent, and Nichola Cruickshanks
- Subjects
Programmed cell death ,Indoles ,Mice, Nude ,Breast Neoplasms ,Biology ,Lapatinib ,p38 Mitogen-Activated Protein Kinases ,Mice ,eIF-2 Kinase ,chemistry.chemical_compound ,Cell Line, Tumor ,Antineoplastic Combined Chemotherapy Protocols ,Autophagy ,medicine ,Animals ,Humans ,Mitogen-Activated Protein Kinase 9 ,PTEN ,HSP70 Heat-Shock Proteins ,Mitogen-Activated Protein Kinase 8 ,Pyrroles ,Protein kinase A ,Pharmacology ,EIF-2 kinase ,Membrane Proteins ,Articles ,Endoplasmic Reticulum Stress ,Mitochondria ,Cell killing ,chemistry ,Quinazolines ,Cancer research ,biology.protein ,Molecular Medicine ,Female ,Reactive Oxygen Species ,Obatoclax ,medicine.drug - Abstract
Previous studies showed that lapatinib and obatoclax interact in a greater-than-additive fashion to cause cell death and do so through a toxic form of autophagy. The present studies sought to extend our analyses. Lapatinib and obatoclax killed multiple tumor cell types, and cells lacking phosphatase and tensin homolog (PTEN) function were relatively resistant to drug combination lethality; expression of PTEN in PTEN-null breast cancer cells restored drug sensitivity. Coadministration of lapatinib with obatoclax elicited autophagic cell death that was attributable to the actions of mitochondrial reactive oxygen species. Wild-type cells but not mitochondria-deficient rho-zero cells were radiosensitized by lapatinib and obatoclax treatment. Activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun NH(2)-terminal kinase 1/2 (JNK1/2) by the drug combination was enhanced by radiation, and signaling by p38 MAPK and JNK1/2 promoted cell killing. In immunohistochemical analyses, the autophagosome protein p62 was determined to be associated with protein kinase-like endoplasmic reticulum kinase (PERK) and inositol-requiring enzyme 1, as well as with binding immunoglobulin protein/78-kDa glucose-regulated protein, in drug combination-treated cells. Knockdown of PERK suppressed drug-induced autophagy and protected tumor cells from the drug combination. Knockdown of PERK suppressed the reduction in Mcl-1 expression after drug combination exposure, and overexpression of Mcl-1 protected cells. Our data indicate that mitochondrial function plays an essential role in cell killing by lapatinib and obatoclax, as well as radiosensitization by this drug combination.
- Published
- 2012
49. CDK Inhibitors Upregulate BH3-Only Proteins to Sensitize Human Myeloma Cells to BH3 Mimetic Therapies
- Author
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Gary Lee Simmons, Paul Dent, Lora Kramer, Dustin Larsen, Justin D. Richey, Xin Yan Pei, Yun Dai, Mandy Garnett, Li Wang, Steven Grant, Daniella M. Schwartz, Jennifer Myers, Florence Su, Shuang Chen, and Robert Z. Orlowski
- Subjects
Cancer Research ,Programmed cell death ,Indoles ,bcl-X Protein ,Mice, Nude ,Apoptosis ,Mice, SCID ,Article ,Small hairpin RNA ,Mice ,chemistry.chemical_compound ,Piperidines ,Downregulation and upregulation ,Biomimetic Materials ,Mice, Inbred NOD ,Cyclin-dependent kinase ,Cell Line, Tumor ,Proto-Oncogene Proteins ,hemic and lymphatic diseases ,Antineoplastic Combined Chemotherapy Protocols ,Animals ,Humans ,Pyrroles ,Protein Kinase Inhibitors ,Flavonoids ,Bcl-2-Like Protein 11 ,biology ,Kinase ,Membrane Proteins ,Drug Synergism ,Xenograft Model Antitumor Assays ,Molecular biology ,Cyclin-Dependent Kinases ,Peptide Fragments ,Mitochondria ,Up-Regulation ,Proto-Oncogene Proteins c-bcl-2 ,Oncology ,chemistry ,Membrane protein ,Cancer research ,biology.protein ,Myeloid Cell Leukemia Sequence 1 Protein ,biological phenomena, cell phenomena, and immunity ,Apoptosis Regulatory Proteins ,Multiple Myeloma ,Obatoclax - Abstract
BH3 mimetic drugs induce cell death by antagonizing the activity of antiapoptotic Bcl-2 family proteins. Cyclin-dependent kinase (CDK) inhibitors that function as transcriptional repressors downregulate the Bcl-2 family member Mcl-1 and increase the activity of selective BH3 mimetics that fail to target this protein. In this study, we determined whether CDK inhibitors potentiate the activity of pan-BH3 mimetics directly neutralizing Mcl-1. Specifically, we evaluated interactions between the prototypical pan-CDK inhibitor flavopiridol and the pan-BH3 mimetic obatoclax in multiple myeloma (MM) cells in which Mcl-1 is critical for survival. Coadministration of flavopiridol and obatoclax synergistically triggered apoptosis in both drug-naïve and drug-resistant MM cells. Mechanistic investigations revealed that flavopiridol inhibited Mcl-1 transcription but increased transcription of Bim and its binding to Bcl-2/Bcl-xL. Obatoclax prevented Mcl-1 recovery and caused release of Bim from Bcl-2/Bcl-xL and Mcl-1, accompanied by activation of Bax/Bak. Whether administered singly or in combination with obatoclax, flavopiridol also induced upregulation of multiple BH3-only proteins, including BimEL, BimL, Noxa, and Bik/NBK. Notably, short hairpin RNA knockdown of Bim or Noxa abrogated lethality triggered by the flavopiridol/obatoclax combination in vitro and in vivo. Together, our findings show that CDK inhibition potentiates pan-BH3 mimetic activity through a cooperative mechanism involving upregulation of BH3-only proteins with coordinate downregulation of their antiapoptotic counterparts. These findings have immediate implications for the clinical trial design of BH3 mimetic-based therapies that are presently being studied intensively for the treatment of diverse hematopoietic malignancies, including lethal multiple myeloma. Cancer Res; 72(16); 4225–37. ©2012 AACR.
- Published
- 2012
50. Sorafenib and pemetrexed toxicity in cancer cells is mediated via SRC-ERK signaling
- Author
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Steven Grant, Paul Dent, Jeremy C. Allegood, Andrew Poklepovic, Sarah Spiegel, Besim Ogretmen, Nichola Cruickshanks, Margaret A. Park, Hossein A. Hamed, and M. Danielle Bareford
- Subjects
Niacinamide ,MAPK/ERK pathway ,Sorafenib ,Cancer Research ,medicine.medical_specialty ,Ceramide ,Guanine ,MAP Kinase Signaling System ,Pyridines ,Antineoplastic Agents ,Breast Neoplasms ,Endosomes ,Pemetrexed ,Biology ,Receptor, Platelet-Derived Growth Factor beta ,chemistry.chemical_compound ,Glutamates ,Cell Line, Tumor ,Internal medicine ,Autophagy ,medicine ,Humans ,Protein Phosphatase 2 ,Extracellular Signal-Regulated MAP Kinases ,Ceramide synthase ,Pharmacology ,Phenylurea Compounds ,Benzenesulfonates ,Drug Synergism ,Protein phosphatase 2 ,Enzyme Activation ,src-Family Kinases ,Endocrinology ,Oncology ,chemistry ,Gene Knockdown Techniques ,Cancer cell ,Cancer research ,Molecular Medicine ,Female ,RNA Interference ,Research Paper ,Proto-oncogene tyrosine-protein kinase Src ,medicine.drug - Abstract
The present studies sought to further understand how the anti-folate pemetrexed and the multi-kinase inhibitor sorafenib interact to kill tumor cells. Sorafenib activated SRC, and via SRC the drug combination activated ERK1/2. Expression of dominant negative SRC or dominant negative MEK1 abolished drug-induced ERK1/2 activation, together with drug-induced autophagy, acidic lysosome formation, and tumor cell killing. Protein phosphatase 2A is an important regulator of the ERK1/2 pathway. Fulvestrant resistant MCF7 cells expressed higher levels of the PP2A inhibitor SET/I2PP2A, had lower endogenous PP2A activity, and had elevated basal ERK1/2 activity compared with their estrogen dependent counterparts. Overexpression of I2PP2A blocked drug-induced activation of ERK1/2 and tumor cell killing. PP2A can be directly activated by ceramide and SET/I2PP2A can be inhibited by ceramide. Inhibition of the de novo ceramide synthase pathway blocked drug-induced ceramide generation, PP2A activation and tumor cell killing. Collectively these findings demonstrate that ERK1/2 plays an essential role downstream of SRC in pemetrexed and sorafenib lethality and that PP2A plays an important role in regulating this process.
- Published
- 2012
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