49 results on '"Marcellus R"'
Search Results
2. Explosives leaking from dumped munition contaminate fish from German coastal waters: a reason for chronic effects?
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Ulrike Kammann, Verena Töpker, Nicole Schmidt, Marcellus Rödiger, Marc-Oliver Aust, Michael Gabel, and Jörn Peter Scharsack
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Dumped munition ,Explosives ,TNT ,HMX ,Baltic Sea ,North Sea ,Environmental sciences ,GE1-350 ,Environmental law ,K3581-3598 - Abstract
Abstract Background Conventional munition dumped into the North Sea and the Baltic Sea close to the German coastline is corroding. A major concern is that biota, including fish, are negatively affected by toxic explosives leaking into marine environments. With the present study, we investigated fish living in close proximity to munition dumping sites for contamination and for signs of health impairments. The flat fish species common dab (Limanda limanda) was used as a model, since it lives in the vicinity of dumping sites and exhibits minor migratory activity. Since explosives are excreted via the bile, the bile fluids from dab were analysed. Further on we inspected the health status of the fish. Results Dab caught in German coastal waters of the Baltic Sea and the North Sea were contaminated with explosives. Probably due to rapid metabolization, concentrations of the explosive 2,4,6-trinitrotoluene (TNT) were always below limit of detection, but its metabolites 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene were detected in bile fluid up to 26.36 ng/ml and 95.91 ng/ml, respectively. Only few fish from the Baltic Sea were positive for the explosive HMX, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine with a maximum concentration of 0.89 ng/ml. Highest concentrations of TNT metabolites in bile fluid were detected in dab collected near the dumping site “Kolberger Heide” in the bay of Kiel (Baltic Sea). However, also dab from the North Sea were significantly contaminated with TNT metabolites. Conclusions The present study showed for the first time that fish living close to near shore munition dumping sites in the North Sea are contaminated with explosives. Various health indicators (body condition factors, externally visible fish diseases, parasites or liver anomalies) showed differences in health status between fish living in the North Sea and in the Baltic Sea, respectively. However, the health status of fish caught at the most contaminated site in the Baltic Sea was not worse compared to fish living in less contaminated areas. We conclude that fish living in the vicinity of dumping sites in the North Sea and the Baltic Sea can be significantly contaminated with explosives. However, obvious health impairments of the fish were not observed.
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- 2024
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3. The adenovirus E4orf4 protein induces growth arrest and mitotic catastrophe in H1299 human lung carcinoma cells
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Li, S, Szymborski, A, Miron, M-J, Marcellus, R, Binda, O, Lavoie, J N, and Branton, P E
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- 2009
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4. OVERSEAS DISTRIBUTORSHIP AGREEMENTS
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MEEK, MARCELLUS R.
- Published
- 1966
5. Atlantic cod (Gadus morhua) assessment approaches in the North and Baltic Sea: A comparison of environmental DNA analysis versus bottom trawl sampling
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Yassine Kasmi, Tina Blancke, Erik Eschbach, Benita Möckel, Laura Casas, Matthias Bernreuther, Pedro Nogueira, Gertrud Delfs, Samira Kadhim, Timo Meißner, Marcellus Rödiger, Amina Eladdadi, Christoph Stransky, and Reinhold Hanel
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Environmental DNA (eDNA) ,quantitative eDNA analysis ,bottom trawl sampling ,Gadus morhua ,North Sea ,Baltic Sea ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
The assessment of fish stocks is often dependent on scientific trawl fisheries surveys, which are both invasive and costly. The analysis of environmental DNA (eDNA) from water samples is regarded as a non-invasive and cost-effective alternative, but meaningful performance evaluations are required for a wider application. The goal of this study was to comparatively analyze a newly developed, more sensitive real-time PCR based eDNA approach with bottom trawl fisheries catches to locally detect and quantify Atlantic cod (Gadus morhua) in the North and Baltic Seas. With a species-specificity of the qPCR assay of 100%, a minimal limit of 15 Cytochrome b eDNA copies was determined for the detection of cod. In addition, a Gaussian processing regression proved a significant correlation (95%) between eDNA (copies per L of water) and cod biomass (CPUE/Ha) found by bottom trawling. The results presented here prove the potential of eDNA analyses for quantitative assessments of commercial fish stocks in the open ocean, although additional comparative analyses are needed to demonstrate its performance under different oceanographic conditions.
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- 2023
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6. Maintenance software review: the art of roofing condition inspections
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Vanier, D. J., Doshi, H., Kyle, B. R., and Marcellus, R. W.
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Roofs ,Toitures - Published
- 1998
7. A Theoretical dynamic ice-structure interaction model for crushing with extrusion
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Marcellus, R. W., Sander, M., Sinha, N. K., Shah, U. K., and Amer. Soc. for Testing and Materials
- Abstract
Proc. 9th Int. Conf. Offshore Mechanics and Arctic Engineering: 18 February 1990, Houston, TX
- Published
- 1990
8. 134 POSTER The rational design of inhibitors of the telomere-hnRNP A1 interaction
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Billot, X., Marcellus, R., Belec, L., Trempe, J.F., Safaee, N., Gehring, K., Schrag, J., Cygler, M., Lawless, M., and Beauparlant, P.
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- 2008
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9. Found Myself in Jail Again.
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Marcellus, R. Kimm
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- FOUND Myself in Jail Again (Poem), KIMM, R.
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The article presents the poem "Found Myself in Jail Again," by R. Kimm. First Line: Last Line: You were so full'a joy; Last Line: cat-dozed "road"...
- Published
- 2008
10. Effect of N-acetyl-L-cysteine on lymphocyte apoptosis, lymphocyte viability, TNF-alpha and IL-8 in HIV-infected patients undergoing anti-retroviral treatment
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Aricio Treitinger, Celso Spada, Ivete Yoshico Masokawa, Júlio César Vidal Verdi, Mariette Van Der Sander Silveira, Magali Chaves Luis, Marcellus Reis, Silvia Inês Alejandra Cordova de Pires Ferreira, and Dulcinéia Saes Parra Abdalla
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N-acetylcysteine ,apoptosis ,viability ,HIV ,glutathione ,TNF-alpha ,IL-8 ,Infectious and parasitic diseases ,RC109-216 ,Microbiology ,QR1-502 - Abstract
N-acetyl-L-cysteine (NAC) has been proposed as an additional therapeutic agent for AIDS patients because it reduces human immunodeficiency virus type 1 (HIV-1) replication in stimulated CD4+ lymphocytes, and it ameliorates immunological reactivity. In a randomized, 180-day, double-blind, placebo-controlled trial performed with HIV-infected patients classified as A2 and A3 according to the criteria of the Center for Disease Control and Prevention, we investigated the effects of oral administration of NAC on HIV-infected patients undergoing their first anti-retroviral therapy; viral load, CD4+ lymphocyte, lymphocyte viability and apoptosis, and TNF-alpha and IL-8 levels were determined. Sixteen patients who received anti-retroviral therapy plus a placebo formed the control group and the study group consisted of 14 patients who received anti-retroviral therapy and NAC supplementation. A significant decrease was seen in viral load, TNF-alpha and IL-8 levels, and lymphocyte apoptosis, and a significant increase was found in levels of CD4+ lymphocytes and lymphocyte viability in both groups after anti-retroviral treatment, but no measurable benefits of anti-retroviral therapy plus NAC oral supplementation (600 mg/day) were found in relation to anti-retroviral therapy alone, and the baseline levels of cysteine and glutathione in plasma were not recovered by this treatment. In conclusion, the daily doses of NAC necessary for the total recuperation of plasma cysteine and glutathione levels in HIV-infected patients and the additional benefits following the supplementation of NAC in patients submitted to anti-retroviral therapy, need to be studied further.
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11. Identifying Novel Epigenetic Radiosensitizers in Small Cell Lung Cancer Using a Custom EpiDrug CRISPR Screen.
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Shi, M., Aparnathi, M., Majeed, S., Song, L., Subramaniam, R., Marcellus, R., Al-awar, R., Ketela, T., He, H., and Lok, B.
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- *
SMALL cell lung cancer , *CRISPRS , *EPIGENETICS , *EPIGENOMICS - Published
- 2020
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12. A kinome drug screen identifies multi-TKI synergies and ERBB2 signaling as a therapeutic vulnerability in MYC/TYR subgroup ATRTs.
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Golbourn B, Ho B, Bondoc A, Luck A, Fan X, Richardson E, Marcellus R, Prakesch M, Halbert M, Agrawal N, Smith C, Huang A, and Rutka JT
- Abstract
Background: Atypical Teratoid Rhabdoid Tumor (ATRT) is a rare, devastating, and largely incurable pediatric brain tumor. Although recent studies have uncovered three molecular subgroups of ATRTs with distinct disease patterns, and signaling features, the therapeutic profiles of ATRT subgroups remain incompletely elucidated., Methods: We examined the effect of 465 kinase inhibitors on a panel of ATRT subgroup-specific cell lines. We then applied multi-omics analyses to investigate the underlying molecular mechanism of kinase inhibitor efficacy in ATRT subgroups., Results: We observed that ATRT cell lines are broadly sensitive to inhibitors of the PI3K and MAPK signaling pathways, as well as CDKs, AURKA/B kinases, and PLK1. We identified two classes of multi-kinase inhibitors (MKIs) predominantly targeting receptors tyrosine kinase (RTKs) including PDGFR and EGFR/ERBB2 in MYC/TYR ATRT cells. The PDGFRB inhibitor, Dasatinib, synergistically affected MYC/TYR ATRT cell growth when combined with broad-acting PI3K and MAPK pathway inhibitors, including Rapamycin and Trametinib. We observed that MYC/TYR ATRT cells were also distinctly sensitive to various inhibitors of ERBB2 signaling. Transcriptional, H3K27Ac ChIPSeq, ATACSeq, and HiChIP analyses of primary MYC/TYR ATRTs revealed ERBB2 expression which correlated with differential methylation and activation of a distinct enhancer element by DNA looping. Significantly, we show the brain penetrant EGFR/ERBB2 inhibitor, Afatinib, specifically inhibited in vitro and in vivo growth of MYC/TYR ATRT cells., Conclusions: Taken together our studies suggest combined treatments with PDGFR and ERBB2-directed TKIs with inhibitors of the PI3K and MAPK pathways as an important new therapeutic strategy for the MYC/TYR subgroup of ATRTs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
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- 2024
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13. The Imipridone ONC213 Targets α-Ketoglutarate Dehydrogenase to Induce Mitochondrial Stress and Suppress Oxidative Phosphorylation in Acute Myeloid Leukemia.
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Su Y, Carter JL, Li X, Fukuda Y, Gray A, Lynch J, Edwards H, Ma J, Schreiner P, Polin L, Kushner J, Dzinic SH, Buck SA, Pruett-Miller SM, Hege-Hurrish K, Robinson C, Qiao X, Liu S, Wu S, Wang G, Li J, Allen JE, Prabhu VV, Schimmer AD, Joshi D, Kalhor-Monfared S, Watson IDG, Marcellus R, Isaac MB, Al-Awar R, Taub JW, Lin H, Schuetz JD, and Ge Y
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- Humans, Myeloid Cell Leukemia Sequence 1 Protein metabolism, Cell Line, Tumor, Apoptosis, Oxidative Phosphorylation, Leukemia, Myeloid, Acute drug therapy, Leukemia, Myeloid, Acute metabolism
- Abstract
Eradication of acute myeloid leukemia (AML) is therapeutically challenging; many patients succumb to AML despite initially responding to conventional treatments. Here, we showed that the imipridone ONC213 elicits potent antileukemia activity in a subset of AML cell lines and primary patient samples, particularly in leukemia stem cells, while producing negligible toxicity in normal hematopoietic cells. ONC213 suppressed mitochondrial respiration and elevated α-ketoglutarate by suppressing α-ketoglutarate dehydrogenase (αKGDH) activity. Deletion of OGDH, which encodes αKGDH, suppressed AML fitness and impaired oxidative phosphorylation, highlighting the key role for αKGDH inhibition in ONC213-induced death. ONC213 treatment induced a unique mitochondrial stress response and suppressed de novo protein synthesis in AML cells. Additionally, ONC213 reduced the translation of MCL1, which contributed to ONC213-induced apoptosis. Importantly, a patient-derived xenograft from a relapsed AML patient was sensitive to ONC213 in vivo. Collectively, these findings support further development of ONC213 for treating AML., Significance: In AML cells, ONC213 suppresses αKGDH, which induces a unique mitochondrial stress response, and reduces MCL1 to decrease oxidative phosphorylation and elicit potent antileukemia activity. See related commentary by Boët and Sarry, p. 950., (©2024 American Association for Cancer Research.)
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- 2024
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14. Discovery of Nanomolar DCAF1 Small Molecule Ligands.
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Li ASM, Kimani S, Wilson B, Noureldin M, González-Álvarez H, Mamai A, Hoffer L, Guilinger JP, Zhang Y, von Rechenberg M, Disch JS, Mulhern CJ, Slakman BL, Cuozzo JW, Dong A, Poda G, Mohammed M, Saraon P, Mittal M, Modh P, Rathod V, Patel B, Ackloo S, Santhakumar V, Szewczyk MM, Barsyte-Lovejoy D, Arrowsmith CH, Marcellus R, Guié MA, Keefe AD, Brown PJ, Halabelian L, Al-Awar R, and Vedadi M
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- Humans, Ligands, Carrier Proteins chemistry, Ubiquitin-Protein Ligases metabolism, Neoplasms
- Abstract
DCAF1 is a substrate receptor of two distinct E3 ligases (CRL4
DCAF1 and EDVP), plays a critical physiological role in protein degradation, and is considered a drug target for various cancers. Antagonists of DCAF1 could be used toward the development of therapeutics for cancers and viral treatments. We used the WDR domain of DCAF1 to screen a 114-billion-compound DNA encoded library (DEL) and identified candidate compounds using similarity search and machine learning. This led to the discovery of a compound (Z1391232269) with an SPR KD of 11 μM. Structure-guided hit optimization led to the discovery of OICR-8268 ( 26e ) with an SPR KD of 38 nM and cellular target engagement with EC50 of 10 μM as measured by cellular thermal shift assay (CETSA). OICR-8268 is an excellent tool compound to enable the development of next-generation DCAF1 ligands toward cancer therapeutics, further investigation of DCAF1 functions in cells, and the development of DCAF1-based PROTACs.- Published
- 2023
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15. Discovery of OICR12694: A Novel, Potent, Selective, and Orally Bioavailable BCL6 BTB Inhibitor.
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Mamai A, Chau AM, Wilson BJ, Watson ID, Joseph BB, Subramanian PR, Morshed MM, Morin JA, Prakesch MA, Lu T, Connolly P, Kuntz DA, Pomroy NC, Poda G, Nguyen K, Marcellus R, Strathdee G, Theriault B, Subramaniam R, Mohammed M, Abibi A, Chan M, Winston J, Kiyota T, Undzys E, Aman A, Austin N, Du Jardin M, Packman K, Phillippar U, Attar R, Edwards J, O'Meara J, Uehling DE, Al-Awar R, Privé GG, and Isaac MB
- Abstract
B cell lymphoma 6 (BCL6), a highly regulated transcriptional repressor, is deregulated in several forms of non-Hodgkin lymphoma (NHL), most notably in diffuse large B-cell lymphoma (DLBCL). The activities of BCL6 are dependent on protein-protein interactions with transcriptional co-repressors. To find new therapeutic interventions addressing the needs of patients with DLBCL, we initiated a program to identify BCL6 inhibitors that interfere with co-repressor binding. A virtual screen hit with binding activity in the high micromolar range was optimized by structure-guided methods, resulting in a novel and highly potent inhibitor series. Further optimization resulted in the lead candidate 58 (OICR12694/JNJ-65234637), a BCL6 inhibitor with low nanomolar DLBCL cell growth inhibition and an excellent oral pharmacokinetic profile. Based on its overall favorable preclinical profile, OICR12694 is a highly potent, orally bioavailable candidate for testing BCL6 inhibition in DLBCL and other neoplasms, particularly in combination with other therapies., Competing Interests: The authors declare no competing financial interest., (© 2023 American Chemical Society.)
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- 2023
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16. G protein-coupled receptor kinase 6 (GRK6) regulates insulin processing and secretion via effects on proinsulin conversion to insulin.
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Varney MJ, Steyaert W, Coucke PJ, Delanghe JR, Uehling DE, Joseph B, Marcellus R, Al-Awar R, and Benovic JL
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- Animals, Mice, Glucose pharmacology, Cell Line, Diabetes Mellitus, Type 2 genetics, Insulin metabolism, Proinsulin genetics, Proinsulin metabolism, G-Protein-Coupled Receptor Kinases genetics, G-Protein-Coupled Receptor Kinases metabolism
- Abstract
Recent studies identified a missense mutation in the gene coding for G protein-coupled receptor kinase 6 (GRK6) that segregates with type 2 diabetes (T2D). To better understand how GRK6 might be involved in T2D, we used pharmacological inhibition and genetic knockdown in the mouse β-cell line, MIN6, to determine whether GRK6 regulates insulin dynamics. We show inhibition of GRK5 and GRK6 increased insulin secretion but reduced insulin processing while GRK6 knockdown revealed these same processing defects with reduced levels of cellular insulin. GRK6 knockdown cells also had attenuated insulin secretion but enhanced proinsulin secretion consistent with decreased processing. In support of these findings, we demonstrate GRK6 rescue experiments in knockdown cells restored insulin secretion after glucose treatment. The altered insulin profile appears to be caused by changes in the proprotein convertases, the enzymes responsible for proinsulin to insulin conversion, as GRK6 knockdown resulted in significantly reduced convertase expression and activity. To identify how the GRK6-P384S mutation found in T2D patients might affect insulin processing, we performed biochemical and cell biological assays to study the properties of the mutant. We found that while GRK6-P384S was more active than WT GRK6, it displayed a cytosolic distribution in cells compared to the normal plasma membrane localization of GRK6. Additionally, GRK6 overexpression in MIN6 cells enhanced proinsulin processing, while GRK6-P384S expression had little effect. Taken together, our data show that GRK6 regulates insulin processing and secretion in a glucose-dependent manner and provide a foundation for understanding the contribution of GRK6 to T2D., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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17. Correction to "Design, Synthesis, and Characterization of 4-Aminoquinazolines as Potent Inhibitors of the G Protein-Coupled Receptor Kinase 6 (GRK6) for the Treatment of Multiple Myeloma".
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Uehling DE, Joseph B, Chung KC, Zhang AX, Ler S, Prakesch MA, Poda G, Grouleff J, Aman A, Kiyota T, Leung-Hagesteijn C, Konda JD, Marcellus R, Griffin C, Subramaniam R, Abibi A, Strathdee CA, Isaac MB, Al-Awar R, and Tiedemann RE
- Published
- 2022
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18. Chemical Genetics Screen Identifies COPB2 Tool Compounds That Alters ER Stress Response and Induces RTK Dysregulation in Lung Cancer Cells.
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Saraon P, Snider J, Schormann W, Rai A, Radulovich N, Sánchez-Osuna M, Coulombe-Huntington J, Huard C, Mohammed M, Lima-Fernandes E, Thériault B, Halabelian L, Chan M, Joshi D, Drecun L, Yao Z, Pathmanathan S, Wong V, Lyakisheva A, Aboualizadeh F, Niu L, Li F, Kiyota T, Subramanian R, Joseph B, Aman A, Prakesch M, Isaac M, Mamai A, Poda G, Vedadi M, Marcellus R, Uehling D, Leighl N, Sacher A, Samaržija M, Jakopović M, Arrowsmith C, Tyers M, Tsao MS, Andrews D, Al-Awar R, and Stagljar I
- Subjects
- Drug Screening Assays, Antitumor, ErbB Receptors antagonists & inhibitors, ErbB Receptors genetics, ErbB Receptors metabolism, Humans, Mutation, Protein Kinase Inhibitors pharmacology, Protein Processing, Post-Translational, Receptor Protein-Tyrosine Kinases metabolism, Signal Transduction drug effects, Coatomer Protein genetics, Coatomer Protein metabolism, Drug Discovery methods, Endoplasmic Reticulum Stress drug effects, Endoplasmic Reticulum Stress genetics, Gene Expression Regulation, Neoplastic drug effects, Receptor Protein-Tyrosine Kinases genetics
- Abstract
Activating mutations in the epidermal growth factor receptor (EGFR) are common driver mutations in non-small cell lung cancer (NSCLC). First, second and third generation EGFR tyrosine kinase inhibitors (TKIs) are effective at inhibiting mutant EGFR NSCLC, however, acquired resistance is a major issue, leading to disease relapse. Here, we characterize a small molecule, EMI66, an analog of a small molecule which we previously identified to inhibit mutant EGFR signalling via a novel mechanism of action. We show that EMI66 attenuates receptor tyrosine kinase (RTK) expression and signalling and alters the electrophoretic mobility of Coatomer Protein Complex Beta 2 (COPB2) protein in mutant EGFR NSCLC cells. Moreover, we demonstrate that EMI66 can alter the subcellular localization of EGFR and COPB2 within the early secretory pathway. Furthermore, we find that COPB2 knockdown reduces the growth of mutant EGFR lung cancer cells, alters the post-translational processing of RTKs, and alters the endoplasmic reticulum (ER) stress response pathway. Lastly, we show that EMI66 treatment also alters the ER stress response pathway and inhibits the growth of mutant EGFR lung cancer cells and organoids. Our results demonstrate that targeting of COPB2 with EMI66 presents a viable approach to attenuate mutant EGFR signalling and growth in NSCLC., Competing Interests: Declaration of interests I.S., P.S. and J.S. (in conjunction with the University of Toronto) are listed as inventors on a patent (publication number 20190091205) for the use of EMI1 (and structurally related analogues), midostaurin, gilteritinib and AZD7762 (and structurally related analogues) in the treatment of mutant EGFR-mediated non-small-cell lung cancer., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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19. Design, Synthesis, and Characterization of 4-Aminoquinazolines as Potent Inhibitors of the G Protein-Coupled Receptor Kinase 6 (GRK6) for the Treatment of Multiple Myeloma.
- Author
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Uehling DE, Joseph B, Chung KC, Zhang AX, Ler S, Prakesch MA, Poda G, Grouleff J, Aman A, Kiyota T, Leung-Hagesteijn C, Konda JD, Marcellus R, Griffin C, Subramaniam R, Abibi A, Strathdee CA, Isaac MB, Al-Awar R, and Tiedemann RE
- Subjects
- Animals, Antineoplastic Agents chemical synthesis, Antineoplastic Agents chemistry, Cell Proliferation drug effects, Cell Survival drug effects, Dose-Response Relationship, Drug, Drug Screening Assays, Antitumor, G-Protein-Coupled Receptor Kinases metabolism, Humans, Mice, Models, Molecular, Molecular Structure, Multiple Myeloma metabolism, Multiple Myeloma pathology, Protein Kinase Inhibitors chemical synthesis, Protein Kinase Inhibitors chemistry, Quinazolines chemical synthesis, Quinazolines chemistry, Structure-Activity Relationship, Antineoplastic Agents pharmacology, Drug Design, G-Protein-Coupled Receptor Kinases antagonists & inhibitors, Multiple Myeloma drug therapy, Protein Kinase Inhibitors pharmacology, Quinazolines pharmacology
- Abstract
Both previous and additional genetic knockdown studies reported herein implicate G protein-coupled receptor kinase 6 (GRK6) as a critical kinase required for the survival of multiple myeloma (MM) cells. Therefore, we sought to develop a small molecule GRK6 inhibitor as an MM therapeutic. From a focused library of known kinase inhibitors, we identified two hits with moderate biochemical potencies against GRK6. From these hits, we developed potent (IC
50 < 10 nM) analogues with selectivity against off-target kinases. Further optimization led to the discovery of an analogue ( 18 ) with an IC50 value of 6 nM against GRK6 and selectivity against a panel of 85 kinases. Compound 18 has potent cellular target engagement and antiproliferative activity against MM cells and is synergistic with bortezomib. In summary, we demonstrate that targeting GRK6 with small molecule inhibitors represents a promising approach for MM and identify 18 as a novel, potent, and selective GRK6 inhibitor.- Published
- 2021
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20. Lineage-defined leiomyosarcoma subtypes emerge years before diagnosis and determine patient survival.
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Anderson ND, Babichev Y, Fuligni F, Comitani F, Layeghifard M, Venier RE, Dentro SC, Maheshwari A, Guram S, Wunker C, Thompson JD, Yuki KE, Hou H, Zatzman M, Light N, Bernardini MQ, Wunder JS, Andrulis IL, Ferguson P, Razak ARA, Swallow CJ, Dowling JJ, Al-Awar RS, Marcellus R, Rouzbahman M, Gerstung M, Durocher D, Alexandrov LB, Dickson BC, Gladdy RA, and Shlien A
- Subjects
- Adult, Aged, Aged, 80 and over, Clonal Evolution, Cohort Studies, Female, Humans, Leiomyosarcoma classification, Leiomyosarcoma diagnosis, Male, Middle Aged, Muscle, Smooth pathology, Mutation, RNA-Seq methods, Survival Analysis, Gene Expression Profiling methods, Gene Expression Regulation, Neoplastic, Genetic Predisposition to Disease genetics, Genomics methods, Leiomyosarcoma genetics, Muscle, Smooth metabolism
- Abstract
Leiomyosarcomas (LMS) are genetically heterogeneous tumors differentiating along smooth muscle lines. Currently, LMS treatment is not informed by molecular subtyping and is associated with highly variable survival. While disease site continues to dictate clinical management, the contribution of genetic factors to LMS subtype, origins, and timing are unknown. Here we analyze 70 genomes and 130 transcriptomes of LMS, including multiple tumor regions and paired metastases. Molecular profiling highlight the very early origins of LMS. We uncover three specific subtypes of LMS that likely develop from distinct lineages of smooth muscle cells. Of these, dedifferentiated LMS with high immune infiltration and tumors primarily of gynecological origin harbor genomic dystrophin deletions and/or loss of dystrophin expression, acquire the highest burden of genomic mutation, and are associated with worse survival. Homologous recombination defects lead to genome-wide mutational signatures, and a corresponding sensitivity to PARP trappers and other DNA damage response inhibitors, suggesting a promising therapeutic strategy for LMS. Finally, by phylogenetic reconstruction, we present evidence that clones seeding lethal metastases arise decades prior to LMS diagnosis., (© 2021. The Author(s).)
- Published
- 2021
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21. Emergence of Enzalutamide Resistance in Prostate Cancer is Associated with BCL-2 and IKKB Dependencies.
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Liang Y, Jeganathan S, Marastoni S, Sharp A, Figueiredo I, Marcellus R, Mawson A, Shalev Z, Pesic A, Sweet J, Guo H, Uehling D, Gurel B, Neeb A, He HH, Montgomery B, Koritzinsky M, Oakes S, de Bono JS, Gleave M, Zoubeidi A, Wouters BG, and Joshua AM
- Subjects
- Antineoplastic Combined Chemotherapy Protocols therapeutic use, Benzamides therapeutic use, Bridged Bicyclo Compounds, Heterocyclic pharmacology, Bridged Bicyclo Compounds, Heterocyclic therapeutic use, Cell Line, Tumor, Drug Resistance, Neoplasm drug effects, Gene Knockdown Techniques, Humans, I-kappa B Kinase antagonists & inhibitors, I-kappa B Kinase genetics, Male, Nitriles therapeutic use, Phenylthiohydantoin therapeutic use, Prostate pathology, Prostate surgery, Prostatectomy, Prostatic Neoplasms, Castration-Resistant pathology, Prostatic Neoplasms, Castration-Resistant surgery, Proto-Oncogene Proteins c-bcl-2 antagonists & inhibitors, Proto-Oncogene Proteins c-bcl-2 genetics, Sulfonamides pharmacology, Sulfonamides therapeutic use, Xenograft Model Antitumor Assays, Antineoplastic Combined Chemotherapy Protocols pharmacology, Benzamides pharmacology, I-kappa B Kinase metabolism, Nitriles pharmacology, Phenylthiohydantoin pharmacology, Prostatic Neoplasms, Castration-Resistant therapy, Proto-Oncogene Proteins c-bcl-2 metabolism
- Abstract
Purpose: Although enzalutamide (ENZ) has been widely used to treat de novo or castration-resistant metastatic prostate cancer, resistance develops and disease progression is ultimately inevitable. There are currently no approved targeted drugs to specifically delay or overcome ENZ resistance., Experimental Design: We selected several ENZ-resistant cell lines that replicated clinical characteristics of the majority of patients with ENZ-resistant disease. A high-throughput pharmacologic screen was utilized to identify compounds with greater cytotoxic effect for ENZ-resistant cell lines, compared with parental ENZ-sensitive cells. We validated the potential hits in vitro and in vivo , and used knockdown and overexpression assays to study the dependencies in ENZ-resistant prostate cancer., Results: ABT199 (BCL-2 inhibitor) and IMD0354 (IKKB inhibitor) were identified as potent and selective inhibitors of cell viability in ENZ-resistant cell lines in vitro and in vivo which were further validated using loss-of-function assays of BCL-2 and IKKB. Notably, we observed that overexpression of BCL-2 and IKKB in ENZ-sensitive cell lines was sufficient for the emergence of ENZ resistance. In addition, we confirmed that BCL-2 or IKKB inhibitors suppressed the development of ENZ resistance in xenografts. However, validation of both BCL-2 and IKKB in matched castration-sensitive/resistant clinical samples showed that, concurrent with the development of ENZ/abiraterone resistance in patients, only the protein levels of IKKB were increased., Conclusions: Our findings identify BCL-2 and IKKB dependencies in clinically relevant ENZ-resistant prostate cancer cells in vitro and in vivo , but indicate that IKKB upregulation appears to have greater relevance to the progression of human castrate-resistant prostate cancer., (©2021 American Association for Cancer Research.)
- Published
- 2021
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22. A drug discovery platform to identify compounds that inhibit EGFR triple mutants.
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Saraon P, Snider J, Kalaidzidis Y, Wybenga-Groot LE, Weiss K, Rai A, Radulovich N, Drecun L, Vučković N, Vučetić A, Wong V, Thériault B, Pham NA, Park JH, Datti A, Wang J, Pathmanathan S, Aboualizadeh F, Lyakisheva A, Yao Z, Wang Y, Joseph B, Aman A, Moran MF, Prakesch M, Poda G, Marcellus R, Uehling D, Samaržija M, Jakopović M, Tsao MS, Shepherd FA, Sacher A, Leighl N, Akhmanova A, Al-Awar R, Zerial M, and Stagljar I
- Subjects
- Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung genetics, Cell Line, Cell Line, Tumor, DNA Nucleotidyltransferases genetics, Drug Discovery, Drug Resistance, Neoplasm genetics, ErbB Receptors antagonists & inhibitors, ErbB Receptors genetics, Genes, Reporter, Humans, Luciferases genetics, Lung Neoplasms drug therapy, Lung Neoplasms genetics, Mutation, Phosphorylation drug effects, Reproducibility of Results, Small Molecule Libraries pharmacology, Staurosporine analogs & derivatives, Staurosporine pharmacology, High-Throughput Screening Assays methods, Protein Kinase Inhibitors pharmacology
- Abstract
Receptor tyrosine kinases (RTKs) are transmembrane receptors of great clinical interest due to their role in disease. Historically, therapeutics targeting RTKs have been identified using in vitro kinase assays. Due to frequent development of drug resistance, however, there is a need to identify more diverse compounds that inhibit mutated but not wild-type RTKs. Here, we describe MaMTH-DS (mammalian membrane two-hybrid drug screening), a live-cell platform for high-throughput identification of small molecules targeting functional protein-protein interactions of RTKs. We applied MaMTH-DS to an oncogenic epidermal growth factor receptor (EGFR) mutant resistant to the latest generation of clinically approved tyrosine kinase inhibitors (TKIs). We identified four mutant-specific compounds, including two that would not have been detected by conventional in vitro kinase assays. One of these targets mutant EGFR via a new mechanism of action, distinct from classical TKI inhibition. Our results demonstrate how MaMTH-DS is a powerful complement to traditional drug screening approaches.
- Published
- 2020
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23. Benchmarking to the Gold Standard: Hyaluronan-Oxime Hydrogels Recapitulate Xenograft Models with In Vitro Breast Cancer Spheroid Culture.
- Author
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Baker AEG, Bahlmann LC, Tam RY, Liu JC, Ganesh AN, Mitrousis N, Marcellus R, Spears M, Bartlett JMS, Cescon DW, Bader GD, and Shoichet MS
- Subjects
- Animals, Benchmarking, Cell Line, Tumor, Humans, Mice, Phosphatidylinositol 3-Kinases metabolism, Spheroids, Cellular pathology, Breast Neoplasms pathology, Cell Transformation, Neoplastic, Hyaluronic Acid chemistry, Hydrogels chemistry, Hydrogels pharmacology, Oximes chemistry, Spheroids, Cellular drug effects
- Abstract
Many 3D in vitro models induce breast cancer spheroid formation; however, this alone does not recapitulate the complex in vivo phenotype. To effectively screen therapeutics, it is urgently needed to validate in vitro cancer spheroid models against the gold standard of xenografts. A new oxime-crosslinked hyaluronan (HA) hydrogel is designed, manipulating gelation rate and mechanical properties to grow breast cancer spheroids in 3D. This HA-oxime breast cancer model maintains the gene expression profile most similar to that of tumor xenografts based on a pan-cancer gene expression profile (comprising 730 genes) of three different human breast cancer subtypes compared to Matrigel or conventional 2D culture. Differences in gene expression between breast cancer cultures in HA-oxime versus Matrigel or 2D are confirmed for 12 canonical pathways by gene set variation analysis. Importantly, drug response is dependent on the culture method. Breast cancer cells respond better to the Rac inhibitor (EHT-1864) and the PI3K inhibitor (AZD6482) when cultured in HA-oxime versus Matrigel. This study demonstrates the superiority of an HA-based hydrogel as a platform for in vitro breast cancer culture of both primary, patient-derived cells and cell lines, and provides a hydrogel culture model that closely matches that in vivo., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2019
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24. Small molecule epigenetic screen identifies novel EZH2 and HDAC inhibitors that target glioblastoma brain tumor-initiating cells.
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Grinshtein N, Rioseco CC, Marcellus R, Uehling D, Aman A, Lun X, Muto O, Podmore L, Lever J, Shen Y, Blough MD, Cairncross GJ, Robbins SM, Jones SJ, Marra MA, Al-Awar R, Senger DL, and Kaplan DR
- Subjects
- Animals, Antineoplastic Agents pharmacology, Apoptosis drug effects, Cell Line, Tumor, Cell Proliferation drug effects, DNA Damage drug effects, Dexamethasone therapeutic use, Drug Synergism, Drug Therapy, Combination, Epigenesis, Genetic, Histone Deacetylase Inhibitors pharmacology, Humans, Mice, Mice, SCID, Molecular Targeted Therapy, Pyridones pharmacology, Small Molecule Libraries, Xenograft Model Antitumor Assays, Antineoplastic Agents therapeutic use, Brain Neoplasms drug therapy, Drug Screening Assays, Antitumor methods, Enhancer of Zeste Homolog 2 Protein antagonists & inhibitors, Glioblastoma drug therapy, Histone Deacetylase Inhibitors therapeutic use, Pyridones therapeutic use
- Abstract
Glioblastoma (GBM) is the most lethal and aggressive adult brain tumor, requiring the development of efficacious therapeutics. Towards this goal, we screened five genetically distinct patient-derived brain-tumor initiating cell lines (BTIC) with a unique collection of small molecule epigenetic modulators from the Structural Genomics Consortium (SGC). We identified multiple hits that inhibited the growth of BTICs in vitro, and further evaluated the therapeutic potential of EZH2 and HDAC inhibitors due to the high relevance of these targets for GBM. We found that the novel SAM-competitive EZH2 inhibitor UNC1999 exhibited low micromolar cytotoxicity in vitro on a diverse collection of BTIC lines, synergized with dexamethasone (DEX) and suppressed tumor growth in vivo in combination with DEX. In addition, a unique brain-penetrant class I HDAC inhibitor exhibited cytotoxicity in vitro on a panel of BTIC lines and extended survival in combination with TMZ in an orthotopic BTIC model in vivo. Finally, a combination of EZH2 and HDAC inhibitors demonstrated synergy in vitro by augmenting apoptosis and increasing DNA damage. Our findings identify key epigenetic modulators in GBM that regulate BTIC growth and survival and highlight promising combination therapies.
- Published
- 2016
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25. Structure-Based Optimization of a Small Molecule Antagonist of the Interaction Between WD Repeat-Containing Protein 5 (WDR5) and Mixed-Lineage Leukemia 1 (MLL1).
- Author
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Getlik M, Smil D, Zepeda-Velázquez C, Bolshan Y, Poda G, Wu H, Dong A, Kuznetsova E, Marcellus R, Senisterra G, Dombrovski L, Hajian T, Kiyota T, Schapira M, Arrowsmith CH, Brown PJ, Vedadi M, and Al-Awar R
- Subjects
- Animals, Antineoplastic Agents pharmacokinetics, Cell Line, Tumor, Drug Design, Female, Humans, Intracellular Signaling Peptides and Proteins, Mice, Mice, SCID, Models, Molecular, Molecular Docking Simulation, Small Molecule Libraries, Structure-Activity Relationship, X-Ray Diffraction, Antineoplastic Agents chemical synthesis, Antineoplastic Agents pharmacology, Biphenyl Compounds chemical synthesis, Biphenyl Compounds pharmacology, Dihydropyridines chemical synthesis, Dihydropyridines pharmacology, Histone-Lysine N-Methyltransferase antagonists & inhibitors, Histone-Lysine N-Methyltransferase drug effects, Leukemia drug therapy, Myeloid-Lymphoid Leukemia Protein antagonists & inhibitors
- Abstract
WD repeat-containing protein 5 (WDR5) is an important component of the multiprotein complex essential for activating mixed-lineage leukemia 1 (MLL1). Rearrangement of the MLL1 gene is associated with onset and progression of acute myeloid and lymphoblastic leukemias, and targeting the WDR5-MLL1 interaction may result in new cancer therapeutics. Our previous work showed that binding of small molecule ligands to WDR5 can modulate its interaction with MLL1, suppressing MLL1 methyltransferase activity. Initial structure-activity relationship studies identified N-(2-(4-methylpiperazin-1-yl)-5-substituted-phenyl) benzamides as potent and selective antagonists of this protein-protein interaction. Guided by crystal structure data and supported by in silico library design, we optimized the scaffold by varying the C-1 benzamide and C-5 substituents. This allowed us to develop the first highly potent (Kdisp < 100 nM) small molecule antagonists of the WDR5-MLL1 interaction and demonstrate that N-(4-(4-methylpiperazin-1-yl)-3'-(morpholinomethyl)-[1,1'-biphenyl]-3-yl)-6-oxo-4-(trifluoromethyl)-1,6-dihydropyridine-3-carboxamide 16d (OICR-9429) is a potent and selective chemical probe suitable to help dissect the biological role of WDR5.
- Published
- 2016
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26. Downregulation of histone H2A and H2B pathways is associated with anthracycline sensitivity in breast cancer.
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Braunstein M, Liao L, Lyttle N, Lobo N, Taylor KJ, Krzyzanowski PM, Kalatskaya I, Yao CQ, Stein LD, Boutros PC, Twelves CJ, Marcellus R, Bartlett JM, and Spears M
- Subjects
- Adult, Apoptosis drug effects, Breast Neoplasms genetics, Breast Neoplasms pathology, Camptothecin administration & dosage, Camptothecin analogs & derivatives, Doxorubicin administration & dosage, Epirubicin administration & dosage, Female, Gene Expression Regulation, Neoplastic drug effects, Histone Deacetylase Inhibitors administration & dosage, Histones genetics, Humans, Irinotecan, MCF-7 Cells, Middle Aged, Signal Transduction drug effects, Young Adult, Anthracyclines administration & dosage, Breast Neoplasms drug therapy, Drug Resistance, Neoplasm genetics, Histones biosynthesis
- Abstract
Background: Drug resistance in breast cancer is the major obstacle to effective treatment with chemotherapy. While upregulation of multidrug resistance genes is an important component of drug resistance mechanisms in vitro, their clinical relevance remains to be determined. Therefore, identifying pathways that could be targeted in the clinic to eliminate anthracycline-resistant breast cancer remains a major challenge., Methods: We generated paired native and epirubicin-resistant MDA-MB-231, MCF7, SKBR3 and ZR-75-1 epirubicin-resistant breast cancer cell lines to identify pathways contributing to anthracycline resistance. Native cell lines were exposed to increasing concentrations of epirubicin until resistant cells were generated. To identify mechanisms driving epirubicin resistance, we used a complementary approach including gene expression analyses to identify molecular pathways involved in resistance, and small-molecule inhibitors to reverse resistance. In addition, we tested its clinical relevance in a BR9601 adjuvant clinical trial., Results: Characterisation of epirubicin-resistant cells revealed that they were cross-resistant to doxorubicin and SN-38 and had alterations in apoptosis and cell-cycle profiles. Gene expression analysis identified deregulation of histone H2A and H2B genes in all four cell lines. Histone deacetylase small-molecule inhibitors reversed resistance and were cytotoxic for epirubicin-resistant cell lines, confirming that histone pathways are associated with epirubicin resistance. Gene expression of a novel 18-gene histone pathway module analysis of the BR9601 adjuvant clinical trial revealed that patients with low expression of the 18-gene histone module benefited from anthracycline treatment more than those with high expression (hazard ratio 0.35, 95 % confidence interval 0.13-0.96, p = 0.042)., Conclusions: This study revealed a key pathway that contributes to anthracycline resistance and established model systems for investigating drug resistance in all four major breast cancer subtypes. As the histone modification can be targeted with small-molecule inhibitors, it represents a possible means of reversing clinical anthracycline resistance., Trial Registration: ClinicalTrials.gov identifier NCT00003012 . Registered on 1 November 1999.
- Published
- 2016
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27. Erratum: Pharmacological targeting of the Wdr5-MLL interaction in C/EBPα N-terminal leukemia.
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Grebien F, Vedadi M, Getlik M, Giambruno R, Grover A, Avellino R, Skucha A, Vittori S, Kuznetsova E, Smil D, Barsyte-Lovejoy D, Li F, Poda G, Schapira M, Wu H, Dong A, Senisterra G, Stukalov A, Huber KV, Schönegger A, Marcellus R, Bilban M, Bock C, Brown PJ, Zuber J, Bennett KL, Al-Awar R, Delwel R, Nerlov C, Arrowsmith CH, and Superti-Furga G
- Published
- 2015
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28. Pharmacological targeting of the Wdr5-MLL interaction in C/EBPα N-terminal leukemia.
- Author
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Grebien F, Vedadi M, Getlik M, Giambruno R, Grover A, Avellino R, Skucha A, Vittori S, Kuznetsova E, Smil D, Barsyte-Lovejoy D, Li F, Poda G, Schapira M, Wu H, Dong A, Senisterra G, Stukalov A, Huber KVM, Schönegger A, Marcellus R, Bilban M, Bock C, Brown PJ, Zuber J, Bennett KL, Al-Awar R, Delwel R, Nerlov C, Arrowsmith CH, and Superti-Furga G
- Subjects
- Amino Acid Sequence, Animals, CCAAT-Enhancer-Binding Proteins genetics, CCAAT-Enhancer-Binding Proteins metabolism, Cell Differentiation drug effects, Cell Proliferation drug effects, Histone-Lysine N-Methyltransferase genetics, Histone-Lysine N-Methyltransferase metabolism, Histones genetics, Histones metabolism, Humans, Intracellular Signaling Peptides and Proteins, Leukemia, Myeloid, Acute genetics, Leukemia, Myeloid, Acute pathology, Mice, Molecular Docking Simulation, Molecular Sequence Data, Molecular Targeted Therapy, Mutation, Myeloid-Lymphoid Leukemia Protein genetics, Myeloid-Lymphoid Leukemia Protein metabolism, Protein Binding, Protein Isoforms genetics, Protein Isoforms metabolism, Protein Structure, Tertiary, Signal Transduction, Tumor Cells, Cultured, Antineoplastic Agents pharmacology, Biphenyl Compounds pharmacology, Dihydropyridines pharmacology, Gene Expression Regulation, Neoplastic, Histone-Lysine N-Methyltransferase antagonists & inhibitors, Leukemia, Myeloid, Acute metabolism, Myeloid-Lymphoid Leukemia Protein antagonists & inhibitors, Small Molecule Libraries pharmacology
- Abstract
The CEBPA gene is mutated in 9% of patients with acute myeloid leukemia (AML). Selective expression of a short (30-kDa) CCAAT-enhancer binding protein-α (C/EBPα) translational isoform, termed p30, represents the most common type of CEBPA mutation in AML. The molecular mechanisms underlying p30-mediated transformation remain incompletely understood. We show that C/EBPα p30, but not the normal p42 isoform, preferentially interacts with Wdr5, a key component of SET/MLL (SET-domain/mixed-lineage leukemia) histone-methyltransferase complexes. Accordingly, p30-bound genomic regions were enriched for MLL-dependent H3K4me3 marks. The p30-dependent increase in self-renewal and inhibition of myeloid differentiation required Wdr5, as downregulation of the latter inhibited proliferation and restored differentiation in p30-dependent AML models. OICR-9429 is a new small-molecule antagonist of the Wdr5-MLL interaction. This compound selectively inhibited proliferation and induced differentiation in p30-expressing human AML cells. Our data reveal the mechanism of p30-dependent transformation and establish the essential p30 cofactor Wdr5 as a therapeutic target in CEBPA-mutant AML.
- Published
- 2015
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29. (R)-PFI-2 is a potent and selective inhibitor of SETD7 methyltransferase activity in cells.
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Barsyte-Lovejoy D, Li F, Oudhoff MJ, Tatlock JH, Dong A, Zeng H, Wu H, Freeman SA, Schapira M, Senisterra GA, Kuznetsova E, Marcellus R, Allali-Hassani A, Kennedy S, Lambert JP, Couzens AL, Aman A, Gingras AC, Al-Awar R, Fish PV, Gerstenberger BS, Roberts L, Benn CL, Grimley RL, Braam MJ, Rossi FM, Sudol M, Brown PJ, Bunnage ME, Owen DR, Zaph C, Vedadi M, and Arrowsmith CH
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Adaptor Proteins, Signal Transducing metabolism, Dose-Response Relationship, Drug, Enzyme Inhibitors chemistry, Fibroblasts drug effects, Hippo Signaling Pathway, Histone-Lysine N-Methyltransferase genetics, Humans, MCF-7 Cells, Methyltransferases antagonists & inhibitors, Methyltransferases metabolism, Mutation, Phosphoproteins genetics, Phosphoproteins metabolism, Protein Serine-Threonine Kinases genetics, Protein Structure, Tertiary, Pyrrolidines chemistry, Structure-Activity Relationship, Sulfonamides chemistry, Tetrahydroisoquinolines chemistry, Transcription Factors, YAP-Signaling Proteins, Enzyme Inhibitors pharmacology, Epigenesis, Genetic drug effects, Histone-Lysine N-Methyltransferase antagonists & inhibitors, Histone-Lysine N-Methyltransferase metabolism, Pyrrolidines pharmacology, Signal Transduction drug effects, Sulfonamides pharmacology, Tetrahydroisoquinolines pharmacology
- Abstract
SET domain containing (lysine methyltransferase) 7 (SETD7) is implicated in multiple signaling and disease related pathways with a broad diversity of reported substrates. Here, we report the discovery of (R)-PFI-2-a first-in-class, potent (Ki (app) = 0.33 nM), selective, and cell-active inhibitor of the methyltransferase activity of human SETD7-and its 500-fold less active enantiomer, (S)-PFI-2. (R)-PFI-2 exhibits an unusual cofactor-dependent and substrate-competitive inhibitory mechanism by occupying the substrate peptide binding groove of SETD7, including the catalytic lysine-binding channel, and by making direct contact with the donor methyl group of the cofactor, S-adenosylmethionine. Chemoproteomics experiments using a biotinylated derivative of (R)-PFI-2 demonstrated dose-dependent competition for binding to endogenous SETD7 in MCF7 cells pretreated with (R)-PFI-2. In murine embryonic fibroblasts, (R)-PFI-2 treatment phenocopied the effects of Setd7 deficiency on Hippo pathway signaling, via modulation of the transcriptional coactivator Yes-associated protein (YAP) and regulation of YAP target genes. In confluent MCF7 cells, (R)-PFI-2 rapidly altered YAP localization, suggesting continuous and dynamic regulation of YAP by the methyltransferase activity of SETD7. These data establish (R)-PFI-2 and related compounds as a valuable tool-kit for the study of the diverse roles of SETD7 in cells and further validate protein methyltransferases as a druggable target class.
- Published
- 2014
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30. An allosteric inhibitor of protein arginine methyltransferase 3.
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Siarheyeva A, Senisterra G, Allali-Hassani A, Dong A, Dobrovetsky E, Wasney GA, Chau I, Marcellus R, Hajian T, Liu F, Korboukh I, Smil D, Bolshan Y, Min J, Wu H, Zeng H, Loppnau P, Poda G, Griffin C, Aman A, Brown PJ, Jin J, Al-Awar R, Arrowsmith CH, Schapira M, and Vedadi M
- Subjects
- Allosteric Regulation, Allosteric Site, Amino Acid Substitution, Caco-2 Cells, Catalytic Domain, Cell Membrane Permeability, Crystallography, X-Ray, Enzyme Inhibitors metabolism, Humans, Hydrogen Bonding, Kinetics, Microsomes, Liver drug effects, Microsomes, Liver metabolism, Models, Molecular, Mutagenesis, Site-Directed, Protein Binding, Protein Structure, Secondary, Protein-Arginine N-Methyltransferases genetics, Structure-Activity Relationship, Thiadiazoles metabolism, Urea chemistry, Urea metabolism, Enzyme Inhibitors chemistry, Protein-Arginine N-Methyltransferases antagonists & inhibitors, Protein-Arginine N-Methyltransferases chemistry, Thiadiazoles chemistry, Urea analogs & derivatives
- Abstract
PRMT3, a protein arginine methyltransferase, has been shown to influence ribosomal biosynthesis by catalyzing the dimethylation of the 40S ribosomal protein S2. Although PRMT3 has been reported to be a cytosolic protein, it has been shown to methylate histone H4 peptide (H4 1-24) in vitro. Here, we report the identification of a PRMT3 inhibitor (1-(benzo[d][1,2,3]thiadiazol-6-yl)-3-(2-cyclohexenylethyl)urea; compound 1) with IC50 value of 2.5 μM by screening a library of 16,000 compounds using H4 (1-24) peptide as a substrate. The crystal structure of PRMT3 in complex with compound 1 as well as kinetic analysis reveals an allosteric mechanism of inhibition. Mutating PRMT3 residues within the allosteric site or using compound 1 analogs that disrupt interactions with allosteric site residues both abrogated binding and inhibitory activity. These data demonstrate an allosteric mechanism for inhibition of protein arginine methyltransferases, an emerging class of therapeutic targets., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2012
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31. Catalytic site remodelling of the DOT1L methyltransferase by selective inhibitors.
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Yu W, Chory EJ, Wernimont AK, Tempel W, Scopton A, Federation A, Marineau JJ, Qi J, Barsyte-Lovejoy D, Yi J, Marcellus R, Iacob RE, Engen JR, Griffin C, Aman A, Wienholds E, Li F, Pineda J, Estiu G, Shatseva T, Hajian T, Al-Awar R, Dick JE, Vedadi M, Brown PJ, Arrowsmith CH, Bradner JE, and Schapira M
- Subjects
- Adenosine analogs & derivatives, Adenosine pharmacology, Binding, Competitive drug effects, Blotting, Western, Catalysis, Catalytic Domain drug effects, Histone-Lysine N-Methyltransferase, Humans, Kinetics, Methyltransferases metabolism, Phenylurea Compounds pharmacology, Structure-Activity Relationship, Substrate Specificity, Surface Plasmon Resonance, Methyltransferases antagonists & inhibitors
- Abstract
Selective inhibition of protein methyltransferases is a promising new approach to drug discovery. An attractive strategy towards this goal is the development of compounds that selectively inhibit binding of the cofactor, S-adenosylmethionine, within specific protein methyltransferases. Here we report the three-dimensional structure of the protein methyltransferase DOT1L bound to EPZ004777, the first S-adenosylmethionine-competitive inhibitor of a protein methyltransferase with in vivo efficacy. This structure and those of four new analogues reveal remodelling of the catalytic site. EPZ004777 and a brominated analogue, SGC0946, inhibit DOT1L in vitro and selectively kill mixed lineage leukaemia cells, in which DOT1L is aberrantly localized via interaction with an oncogenic MLL fusion protein. These data provide important new insight into mechanisms of cell-active S-adenosylmethionine-competitive protein methyltransferase inhibitors, and establish a foundation for the further development of drug-like inhibitors of DOT1L for cancer therapy.
- Published
- 2012
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32. The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
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Watson M, Roulston A, Bélec L, Billot X, Marcellus R, Bédard D, Bernier C, Branchaud S, Chan H, Dairi K, Gilbert K, Goulet D, Gratton MO, Isakau H, Jang A, Khadir A, Koch E, Lavoie M, Lawless M, Nguyen M, Paquette D, Turcotte E, Berger A, Mitchell M, Shore GC, and Beauparlant P
- Subjects
- Animals, Cell Death drug effects, Cell Line, Tumor, Cyanides pharmacology, Drug Resistance, Neoplasm drug effects, Gene Expression Regulation, Enzymologic drug effects, Gene Expression Regulation, Neoplastic drug effects, Guanidines pharmacology, Humans, Mice, Models, Biological, Models, Molecular, Niacin administration & dosage, Niacin pharmacology, Nicotinamide Phosphoribosyltransferase antagonists & inhibitors, Nicotinamide Phosphoribosyltransferase genetics, Nicotinamide Phosphoribosyltransferase metabolism, Phosphorylation drug effects, Ribose metabolism, Substrate Specificity drug effects, Xenograft Model Antitumor Assays, Cyanides therapeutic use, Guanidines therapeutic use, NAD biosynthesis, Neoplasms drug therapy, Neoplasms enzymology, Nicotinamide Phosphoribosyltransferase deficiency
- Abstract
GMX1777 is a prodrug of the small molecule GMX1778, currently in phase I clinical trials for the treatment of cancer. We describe findings indicating that GMX1778 is a potent and specific inhibitor of the NAD(+) biosynthesis enzyme nicotinamide phosphoribosyltransferase (NAMPT). Cancer cells have a very high rate of NAD(+) turnover, which makes NAD(+) modulation an attractive target for anticancer therapy. Selective inhibition by GMX1778 of NAMPT blocks the production of NAD(+) and results in tumor cell death. Furthermore, GMX1778 is phosphoribosylated by NAMPT, which increases its cellular retention. The cytotoxicity of GMX1778 can be bypassed with exogenous nicotinic acid (NA), which permits NAD(+) repletion via NA phosphoribosyltransferase 1 (NAPRT1). The cytotoxicity of GMX1778 in cells with NAPRT1 deficiency, however, cannot be rescued by NA. Analyses of NAPRT1 mRNA and protein levels in cell lines and primary tumor tissue indicate that high frequencies of glioblastomas, neuroblastomas, and sarcomas are deficient in NAPRT1 and not susceptible to rescue with NA. As a result, the therapeutic index of GMX1777 can be widended in the treatment animals bearing NAPRT1-deficient tumors by coadministration with NA. This provides the rationale for a novel therapeutic approach for the use of GMX1777 in the treatment of human cancers.
- Published
- 2009
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33. The adenovirus E4orf4 protein induces G2/M arrest and cell death by blocking protein phosphatase 2A activity regulated by the B55 subunit.
- Author
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Li S, Brignole C, Marcellus R, Thirlwell S, Binda O, McQuoid MJ, Ashby D, Chan H, Zhang Z, Miron MJ, Pallas DC, and Branton PE
- Subjects
- Cell Count, Cell Line, Tumor, Cell Survival, Humans, Protein Binding, Protein Phosphatase 2 metabolism, Adenoviruses, Human pathogenicity, Cell Cycle, Cell Death, Protein Phosphatase 2 antagonists & inhibitors, Viral Proteins metabolism
- Abstract
Human adenovirus E4orf4 protein is toxic in human tumor cells. Its interaction with the B alpha subunit of protein phosphatase 2A (PP2A) is critical for cell killing; however, the effect of E4orf4 binding is not known. B alpha is one of several mammalian B-type regulatory subunits that form PP2A holoenzymes with A and C subunits. Here we show that E4orf4 protein interacts uniquely with B55 family subunits and that cell killing increases with the level of E4orf4 expression. Evidence suggesting that B alpha-specific PP2A activity, measured in vitro against phosphoprotein substrates, is reduced by E4orf4 binding was obtained, and two potential B55-specific PP2A substrates, 4E-BP1 and p70(S6K), were seen to be hypophosphorylated in vivo following expression of E4orf4. Furthermore, treatment of cells with low levels of the phosphatase inhibitor okadaic acid or coexpression of the PP2A inhibitor I(1)(PP2A) enhanced E4orf4-induced cell killing and G(2)/M arrest significantly. These results suggested that E4orf4 toxicity results from the inhibition of B55-specific PP2A holoenzymes, an idea that was strengthened by an observed growth arrest resulting from treatment of H1299 cells with B alpha-specific RNA interference. We believe that E4orf4 induces growth arrest resulting in cell death by reducing the global level of B55-specific PP2A activity, thus preventing the dephosphorylation of B55-specific PP2A substrates, including those involved in cell cycle progression.
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- 2009
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34. Induction of p53-independent apoptosis by the adenovirus E4orf4 protein requires binding to the Balpha subunit of protein phosphatase 2A.
- Author
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Marcellus RC, Chan H, Paquette D, Thirlwell S, Boivin D, and Branton PE
- Subjects
- Adenovirus E4 Proteins genetics, Adenoviruses, Human genetics, Amino Acid Sequence, Amino Acid Substitution, Genes, p53, Humans, Molecular Sequence Data, Mutagenesis, Site-Directed, Open Reading Frames, Point Mutation, Protein Binding, Protein Phosphatase 2, Protein Structure, Tertiary, Sequence Alignment, Viral Proteins analysis, Viral Proteins genetics, Adenovirus E4 Proteins metabolism, Adenoviruses, Human metabolism, Apoptosis, Phosphoprotein Phosphatases metabolism, Viral Proteins metabolism
- Abstract
Previous studies have indicated that the E4orf4 protein of human adenovirus type 2 (Ad2) induces p53-independent apoptosis. We believe that this process may play a role in cell death and viral spread at the final stages of productive infection. E4orf4 may also be of therapeutic value in treating some diseases, including cancer, through its ability to induce apoptosis when expressed individually. The only previously identified biochemical function of E4orf4 is its ability to associate with the Balpha subunit of protein phosphatase 2A (PP2A). We have used a genetic approach to determine the role of such interactions in E4orf4-induced cell death. E4orf4 deletion mutants were of only limited value, as all were highly defective. We found that E4orf4 proteins from most if not all adenovirus serotypes induced cell death, and thus point mutations were introduced that converted the majority of highly conserved residues to alanines. Such mutants were used to correlate Balpha-subunit binding, association with PP2A activity, and cell killing following the transfection of appropriate cDNAs into p53-null H1299 or C33A cells. The results indicated that binding of the Balpha subunit is essential for induction of cell death, as every mutant that failed to bind efficiently was totally defective for cell killing. This class of mutations (class I) largely involved residues between amino acids 51 and 89. Almost all E4orf4 mutant proteins that associated with PP2A killed cancer cells at high levels; however, several mutants that associated with significant levels of PP2A were defective for killing (class II). Thus, binding of E4orf4 to PP2A is essential for induction of p53-independent apoptosis, but E4orf4 may possess one or more additional functions required for cell killing.
- Published
- 2000
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35. RBP1 induces growth arrest by repression of E2F-dependent transcription.
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Lai A, Marcellus RC, Corbeil HB, and Branton PE
- Subjects
- Animals, CHO Cells, Carrier Proteins genetics, Cricetinae, E2F Transcription Factors, Gene Expression Regulation, Humans, Protein Binding, Retinoblastoma Protein genetics, Retinoblastoma-Binding Protein 1, Transcription Factor DP1, Transcription, Genetic, Carrier Proteins metabolism, Cell Cycle genetics, Cell Cycle Proteins, DNA-Binding Proteins, Repressor Proteins metabolism, Retinoblastoma Protein metabolism, Transcription Factors metabolism
- Abstract
Growth arrest and cell cycle progression are regulated by the retinoblastoma tumour suppressor pRB and related proteins p130 and p107 that bind to and inhibit the E2F family of transcription factors. Although the precise mechanism of this inhibition remains to be established, previous studies indicated the presence of transcriptional repression activity in the 'pocket' of RB family members. We show here that RBP1, a known pRB pocket-binding protein, possesses transcriptional repression activity and associates with p130-E2F and pRB-E2F complexes specifically during growth arrest. Overexpression of RBP1 both inhibited E2F-dependent gene expression and suppressed cell growth. Thus repression of E2F-dependent transcription by RBP1 via RB family members may play a central role in inducing growth arrest.
- Published
- 1999
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36. Analysis of synthesis, stability, phosphorylation, and interacting polypeptides of the 34-kilodalton product of open reading frame 6 of the early region 4 protein of human adenovirus type 5.
- Author
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Boivin D, Morrison MR, Marcellus RC, Querido E, and Branton PE
- Subjects
- Adenovirus E1B Proteins genetics, Adenovirus E1B Proteins metabolism, HeLa Cells, Humans, Open Reading Frames, Phosphorylation, Adenovirus E4 Proteins metabolism, Adenoviruses, Human metabolism, Peptides metabolism
- Abstract
The 34-kDa early-region 4 open reading frame 6 (E4orf6) product of human adenovirus type 5 forms complexes with both the cellular tumor suppressor p53 and the viral E1B 55-kDa protein (E1B-55kDa). E4orf6 can inhibit p53 transactivation activity, as can E1B-55kDa, and in combination these viral proteins cause the rapid turnover of p53. In addition, E4orf6-55kDa complexes play a critical role at later times in the regulation of viral mRNA transport and shutoff of host cell protein synthesis. In the present study, we have further characterized some of the biological properties of E4orf6. Analysis of extracts from infected cells by Western blotting indicated that E4orf6, like E1A and E1B products, is present at high levels until very late times, suggesting that it is available to act throughout the infectious cycle. This pattern is similar to that of E4orf4 but differs markedly from that of another E4 product, E4orf6/7, which is present only transiently. Synthesis of E4orf6 is maximal at early stages but ceases completely with the onset of shutoff of host protein synthesis; however, it was found that unlike E4orf6/7, E4orf6 is very stable, thus allowing high levels to be maintained even at late times. E4orf6 was shown to be phosphorylated at low levels. Coimmunoprecipitation studies in cells lacking p53 indicated that E4orf6 interacts with a number of other proteins. Five of these were shown to be viral or virally induced proteins ranging in size from 102 to 27 kDa, including E1B-55kDa. One such species, of 72 kDa, was shown not to represent the E2 DNA-binding protein and thus remains to be identified. Another appeared to be the L4 100-kDa nonstructural adenovirus late product, but it appeared to be present nonspecifically and not as part of an E4orf6 complex. Apart from p53, three additional cellular proteins, of 84, 19, and 14 kDa were detected by using an adenovirus vector that expresses only E4orf6. The 19-kDa species and a 16-kDa cellular protein were also shown to interact with E4orf6/7. It is possible that complex formation with these viral and cellular proteins plays a role in one or more of the biological activities associated with E4orf6 and E4orf6/7.
- Published
- 1999
- Full Text
- View/download PDF
37. Viruses and apoptosis.
- Author
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Roulston A, Marcellus RC, and Branton PE
- Subjects
- Animals, Humans, Viral Proteins metabolism, Virus Diseases immunology, Virus Replication, Apoptosis, Virus Diseases virology, Virus Physiological Phenomena, Viruses pathogenicity
- Abstract
Successful viral replication requires not only the efficient production and spread of progeny, but also evasion of host defense mechanisms that limit replication by killing infected cells. In addition to inducing immune and inflammatory responses, infection by most viruses triggers apoptosis or programmed cell death of the infected cell. This cell response often results as a compulsory or unavoidable by-product of the action of critical viral replicative functions. In addition, some viruses seem to use apoptosis as a mechanism of cell killing and virus spread. In both cases, successful replication relies on the ability of certain viral products to block or delay apoptosis until sufficient progeny have been produced. Such proteins target a variety of strategic points in the apoptotic pathway. In this review we summarize the great amount of recent information on viruses and apoptosis and offer insights into how this knowledge may be used for future research and novel therapies.
- Published
- 1999
- Full Text
- View/download PDF
38. The early region 4 orf4 protein of human adenovirus type 5 induces p53-independent cell death by apoptosis.
- Author
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Marcellus RC, Lavoie JN, Boivin D, Shore GC, Ketner G, and Branton PE
- Subjects
- Adenovirus E4 Proteins genetics, Adenoviruses, Human genetics, Animals, Cell Line, Cell Line, Transformed, Cricetinae, Gene Expression, HeLa Cells, Humans, Mice, Mutagenesis, Open Reading Frames, Tumor Cells, Cultured, Tumor Suppressor Protein p53 genetics, Adenovirus E4 Proteins physiology, Adenoviruses, Human physiology, Apoptosis, Tumor Suppressor Protein p53 metabolism
- Abstract
Previous studies by our group showed that infection of human and rodent cells by human adenovirus type 5 (Ad5) results in the induction of p53-independent apoptosis and cell death that are dependent upon transactivation of early region 4 (E4). To identify which E4 products are involved, studies were conducted with p53-deficient human SAOS-2 cells infected with various Ad5 E4 mutants. An E4orf6-deficient mutant was defective in cell killing, whereas another that expressed only E4orf6 and E4orf4 killed like wild-type virus, suggesting that E4orf6 may be responsible for cytotoxicity; however, a mutant expressing only E4orf4 induced high levels of cell death, indicating that this E4 product may also be able to induce cytotoxicity. To define the E4 cell death-inducing functions more precisely, cDNAs encoding individual E4 products were introduced into cells by DNA transfection in the absence of other Ad5 proteins. In cotransfections with a cDNA encoding firefly luciferase, enzymatic activity was high in all cases except with E4orf4, where luciferase levels were less than 20% of those in controls. In addition, drug selection of several cell types following transfection with retroviral vector DNA encoding individual E4 products as well as puromycin resistance yielded a large number of cell colonies except when E4orf4 was expressed. These data demonstrated that E4orf4 is the only E4 product capable of independent cell killing. Cell death induced by E4orf4 was due to apoptosis, as evidenced by 4',6-diamidino-2-phenylindole (DAPI) staining of cell nuclei in E4orf4-expressing cells. Thus, although E4orf6 may play some role, these results suggested that E4orf4 may be the major E4 product responsible for induction of p53-independent apoptosis.
- Published
- 1998
- Full Text
- View/download PDF
39. Phosphorylation within the transactivation domain of adenovirus E1A protein by mitogen-activated protein kinase regulates expression of early region 4.
- Author
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Whalen SG, Marcellus RC, Whalen A, Ahn NG, Ricciardi RP, and Branton PE
- Subjects
- Amino Acid Sequence, Animals, CHO Cells, Cricetinae, Cyclic AMP physiology, HeLa Cells, Humans, Mice, Mitogen-Activated Protein Kinase Kinases, Molecular Sequence Data, Phosphorylation, Promoter Regions, Genetic, Protein Kinases metabolism, Adenovirus E1A Proteins physiology, Adenovirus E4 Proteins genetics, Calcium-Calmodulin-Dependent Protein Kinases physiology, Gene Expression Regulation, Viral, Transcriptional Activation
- Abstract
A critical role of the 289-residue (289R) E1A protein of human adenovirus type 5 during productive infection is to transactivate expression of all early viral transcription. Sequences within and proximal to conserved region 3 (CR3) promote expression of these viral genes through interactions with a variety of transcription factors requiring the zinc binding motif in CR3 and in some cases a region at the carboxy-terminal end of CR3, including residues 183 to 188. It is known that 3',5' cyclic AMP (cAMP) reduces the level of phosphorylation of the 289R E1A protein through the activation of protein phosphatase 2A by the E4orf4 protein. This study was designed to identify the E1A phosphorylation sites affected by E4orf4 expression and to determine their importance in regulation of E1A activity. We report here that two previously unidentified sites at Ser-185 and Ser-188 are the targets for decreased phosphorylation in response to cAMP. At least one of these sites, presumably Ser-185, is phosphorylated in vitro by purified mitogen-activated protein kinase (MAPK), and both are hyperphosphorylated in cells which express a constitutively active form of MAPK kinase. Analysis of E1A-mediated transactivation activity indicated that elevated phosphorylation at these sites increased expression of the E4 promoter but not that of E3. We have recently shown that one or more E4 products induce cell death due to p53-independent apoptosis, and thus it seems likely that one role of the E4orf4 protein is to limit production of toxic E4 products by limiting expression of the E4 promoter.
- Published
- 1997
- Full Text
- View/download PDF
40. Regulation of p53 levels by the E1B 55-kilodalton protein and E4orf6 in adenovirus-infected cells.
- Author
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Querido E, Marcellus RC, Lai A, Charbonneau R, Teodoro JG, Ketner G, and Branton PE
- Subjects
- HeLa Cells, Humans, KB Cells, Molecular Weight, Adenovirus E1B Proteins physiology, Adenovirus E4 Proteins physiology, Adenoviruses, Human physiology, Tumor Suppressor Protein p53 metabolism
- Abstract
The adenovirus type 5 243R E1A protein induces p53-dependent apoptosis in the absence of the 19- and 55-kDa E1B polypeptides. This effect appears to result from an accumulation of p53 protein and is unrelated to expression of E1B products. We now report that in the presence of the E1B 55-kDa polypeptide, the 289R E1A protein does not induce such p53 accumulation and, in fact, is able to block that induced by E1A 243R. This inhibition also requires the 289R-dependent transactivation of E4orf6 expression. E4orf6 is known to form complexes with the E1B 55-kDa protein and to function both in the transport and stabilization of viral mRNA and in shutoff of host cell protein synthesis. We demonstrated that the block in p53 accumulation is not due to the generalized shutoff of host cell metabolism. Rather, it appears to result from a mechanism targeted specifically to p53, most likely involving a decrease in the stability of p53 protein. The E1B 55-kDa protein is known to interact with both E4orf6 and p53, and as demonstrated recently by others, we showed that E4orf6 also binds directly to p53. Thus, multiple interactions between all three proteins may regulate p53 stability, resulting in the maintenance of low levels of p53 following virus infection.
- Published
- 1997
- Full Text
- View/download PDF
41. Expression of p53 in Saos-2 osteosarcoma cells induces apoptosis which can be inhibited by Bcl-2 or the adenovirus E1B-55 kDa protein.
- Author
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Marcellus RC, Teodoro JG, Charbonneau R, Shore GC, and Branton PE
- Subjects
- Apoptosis drug effects, DNA-Binding Proteins physiology, Gene Expression Regulation, Neoplastic physiology, Humans, Microscopy, Electron, Osteosarcoma, Tumor Cells, Cultured cytology, Tumor Cells, Cultured physiology, Tumor Cells, Cultured ultrastructure, Adenovirus E1B Proteins pharmacology, Apoptosis physiology, Proto-Oncogene Proteins c-bcl-2 pharmacology, Tumor Suppressor Protein p53 genetics
- Abstract
Studies were carried out to determine the effects of introducing p53 using an adenovirus gene transfer vector into p53 null human Saos-2 osteogenic carcinoma cells. Expression of p53 led to cell death within 30-40 h. The morphology of these cells as determined by electron microscopy indicated that death was by apoptosis. Such death was significantly reduced in Saos-2 variants that express high levels of the Bcl-2 suppressor of apoptosis. It was also found that the E1B-55 kDa protein of human adenovirus type 5, which was known to bind and inactivate p53, blocks Saos-2 cell death following expression of p53. These results thus directly demonstrate that this viral protein is able to inhibit p53-induced apoptosis.
- Published
- 1996
42. Adenovirus type 5 early region 4 is responsible for E1A-induced p53-independent apoptosis.
- Author
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Marcellus RC, Teodoro JG, Wu T, Brough DE, Ketner G, Shore GC, and Branton PE
- Subjects
- 3T3 Cells, Adenovirus E1A Proteins biosynthesis, Adenovirus E1A Proteins genetics, Adenoviruses, Human genetics, Animals, CHO Cells, Cell Line, Cell Survival, Cricetinae, Embryo, Mammalian, Fibroblasts, Humans, Kinetics, Mice, Mutagenesis, Promoter Regions, Genetic, Time Factors, Transcriptional Activation, Adenovirus E1A Proteins physiology, Adenoviruses, Human physiology, Apoptosis, Genes, p53, Tumor Suppressor Protein p53 physiology
- Abstract
In the absence of E1B, the 289- and 243-residue E1A products of human adenovirus type 5 induce p53-dependent apoptosis. However, our group has shown recently that the 289-residue E1A protein is also able to induce apoptosis by a p53-independent mechanism (J. G. Teodoro, G. C. Shore, and P. E. Branton, Oncogene 11:467-474, 1995). Preliminary results suggested that p53-independent cell death required expression of one or more additional adenovirus early gene products. Here we show that both the E1B 19-kDa protein and cellular Bcl-2 inhibit or significantly delay p53-independent apoptosis. Neither early region E2 or E3 appeared to be necessary for such cell death. Analysis of a series of E1A mutants indicated that mutations in the transactivation domain and other regions of E1A correlated with E1A-mediated transactivation of E4 gene expression. Furthermore, p53-deficient human SAOS-2 cells infected with a mutant which expresses E1B but none of the E4 gene products remained viable for considerably longer times than those infected with wild-type adenovirus type 5. In addition, an adenovirus vector lacking both E1 and E4 was unable to induce DNA degradation and cell killing in E1A-expressing cell lines. These data showed that an E4 product is essential for E1A-induced p53-independent apoptosis.
- Published
- 1996
- Full Text
- View/download PDF
43. Importance of the Ser-132 phosphorylation site in cell transformation and apoptosis induced by the adenovirus type 5 E1A protein.
- Author
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Whalen SG, Marcellus RC, Barbeau D, and Branton PE
- Subjects
- Adenoviridae genetics, Adenovirus E1A Proteins genetics, Adenovirus E1A Proteins pharmacology, Amino Acid Sequence, Cell Line, Transformed, Gene Expression Regulation, Viral, Genes, ras, Humans, Molecular Sequence Data, Phosphorylation, Adenoviridae metabolism, Adenovirus E1A Proteins metabolism, Apoptosis drug effects, Cell Transformation, Viral drug effects, Serine metabolism
- Abstract
The 289-residue (289R) and 243R early region 1A (E1A) proteins of human adenovirus type 5 induce cell transformation in cooperation with either E1B or activated ras. Here we report that Ser-132 in both E1A products is a site of phosphorylation in vivo and is the only site phosphorylated in vitro by purified casein kinase II. Ser-132 is located in conserved region 2 near the primary binding site for the pRB tumor suppressor and, in 289R, just upstream of the conserved region 3 transactivation domain involved in regulation of early viral gene expression. Mutants containing alanine or glycine in place of Ser-132 interacted with pRB-related proteins at somewhat reduced efficiency; however, all Ser-132 mutants transformed primary rat cells in cooperation with E1B as well as or better than the wild type when both major E1A proteins were expressed. Such was not the case with mutants expressing only 289R. In cooperation with E1B, the Asp-132 and Gly-132 mutants yielded reduced numbers of smaller transformed foci. With activated ras, all Ser-132 mutants were significantly defective for transformation and the rare foci produced were small and contained extensive areas populated by low densities of flat cells. In the absence of E1B, all Ser-132 mutants induced p53-independent cell death more readily than virus expressing wild-type 289R. These results suggested that phosphorylation at Ser-132 may enhance the binding of pRB and related proteins and also reduce the toxicity of E1A 289R, thus increasing transforming activity.
- Published
- 1996
- Full Text
- View/download PDF
44. High membrane-associated protein kinase C activity correlates to tumorigenicity but not anchorage-independence in a clone of mouse NIH 3T3 cells.
- Author
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Raptis L, Marcellus RC, and Whitfield JF
- Subjects
- 3T3 Cells metabolism, Animals, Antigens, Viral, Tumor, Cell Line, Transformed metabolism, Clone Cells metabolism, Membrane Proteins analysis, Mice, Protein Kinase C analysis, Cell Adhesion, Membrane Proteins metabolism, Neoplasms, Experimental metabolism, Protein Kinase C metabolism
- Abstract
Anchorage-dependent, nontumorigenic rat F111 fibroblasts have a low level of membrane-associated protein kinase C (PKC) activity. After expression of the polyoma virus middle tumor antigen this activity increased, the cells grew in agar and formed tumors after injection into syngeneic rats or nude mice. Contrary to F111, a clone of mouse NIH 3T3 fibroblasts has a high membrane-associated PKC activity and is as tumorigenic as polyoma-transformed cells, although this clone is still anchorage-dependent. Therefore, membrane-associated PKC activation might be one of the signals leading to tumorigenicity but not necessarily anchorage-independence.
- Published
- 1993
- Full Text
- View/download PDF
45. Role of phosphorylation near the amino terminus of adenovirus type 5 early region 1A proteins.
- Author
-
Dumont DJ, Marcellus RC, Bayley ST, and Branton PE
- Subjects
- Animals, Cell Compartmentation, Enhancer Elements, Genetic, Humans, In Vitro Techniques, Mutagenesis, Site-Directed, Nuclear Proteins metabolism, Peptide Fragments chemistry, Phosphoproteins metabolism, Phosphorylation, Rats, Structure-Activity Relationship, Adenovirus E1A Proteins metabolism, Adenoviruses, Human metabolism, Cell Transformation, Viral
- Abstract
Human adenovirus early region 1A (E1A) proteins act as transcriptional regulators and function in the control of DNA synthesis and cell transformation. Little is known about how these viral products are functionally regulated. E1A proteins of adenovirus serotype 5 (Ad5) are phosphorylated at several serine residues and previous studies had indicated that both Ser-89 and Ser-219 are substrates for one or more of the cdc2 family of cell cycle kinases. A second residue near the amino terminus, Ser-96, may also be a site. Although phosphorylation of Ser-89 causes a major shift in gel mobility, the effect on E1A biological activity is unclear. In the present studies we have shown by mutational analysis that phosphorylation at Ser-89 also regulates phosphorylation at Ser-96, suggesting that the gel mobility shift is the result of multiple phosphorylation events. Phosphorylation at Ser-89 did not seem to affect E1A-mediated repression of the simian virus 40 enhancer or trans-activation of the E3 promoter significantly, but it did appear to have a modest but significant effect on transformation of primary baby rat kidney cells.
- Published
- 1993
- Full Text
- View/download PDF
46. Quantitative analysis of regions of adenovirus E1A products involved in interactions with cellular proteins.
- Author
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Barbeau D, Marcellus RC, Bacchetti S, Bayley ST, and Branton PE
- Subjects
- Adenovirus E1A Proteins chemistry, Adenovirus E1A Proteins genetics, Amino Acid Sequence, Binding Sites, Cell Transformation, Viral physiology, Humans, KB Cells, Molecular Sequence Data, Peptide Fragments metabolism, Protein Binding, Sequence Deletion, Adenovirus E1A Proteins metabolism, Cell Cycle, Proteins metabolism
- Abstract
Human adenovirus E1A proteins and oncogene products of several other DNA tumour viruses derive much of their oncogenic potential from interactions with cellular polypeptides. E1A proteins form complexes with p105Rb and a related p107 polypeptide, and with at least three other proteins (p60cycA, p130, and p300); all may be required for cell transformation. Using a series of E1A deletion mutants, we have carried out a quantitative analysis of the binding patterns of cellular proteins to E1A products. Binding of most of the proteins was affected at least partially by mutations within the amino terminal 25 residues, amino acids 36-69 within conserved region 1 (CR1), and residues 121-138 in conserved region 2 (CR2). However, the specific binding characteristics of each protein varied considerably. p300 was the only species for which binding was totally eliminated by deletions at the amino terminus. Removal of regions within CR1 eliminated binding of all species except p107 and p60cycA. Deletion of portions of CR2 reduced or eliminated binding of all proteins except p300. Thus, whereas cellular polypeptides generally were found to interact with the same three regions of E1A proteins, specific interactions varied considerably.
- Published
- 1992
- Full Text
- View/download PDF
47. Cellular ras gene activity is required for full neoplastic transformation by polyomavirus.
- Author
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Raptis L, Marcellus R, Corbley MJ, Krook A, Whitfield J, Anderson SK, and Haliotis T
- Subjects
- Animals, Antigens, Polyomavirus Transforming genetics, Cell Division, Cell Line, Chromosome Deletion, Cloning, Molecular, Introns, Kinetics, Mice, Mice, Inbred C3H, Phenotype, Protein Kinase C metabolism, Proto-Oncogene Proteins p21(ras) genetics, Proto-Oncogene Proteins p21(ras) metabolism, Transcription, Genetic, Transfection, Cell Transformation, Neoplastic, Genes, ras, Polyomavirus genetics
- Abstract
To investigate the role of ras gene activity in cellular transformation by polyomavirus, murine C3H10T1/2 cells were rendered ras deficient by transfection with an antisense ras gene construct. Ras deficiency resulted in a partial suppression of the polyomavirus-induced transformed phenotype. The production of viral middle T antigen and its association with pp60c-src, increased membrane-associated protein kinase C activity, and morphological transformation were unaffected by the downregulation of c-ras gene expression. On the other hand, stimulated proliferation, focus formation on confluent monolayers of normal cells, and colony formation in soft agar were all greatly reduced in cells containing reduced p21ras levels. It is concluded that ras gene activity is needed for full cell transformation by polyomavirus.
- Published
- 1991
- Full Text
- View/download PDF
48. Polyoma virus middle tumor antigen stimulates membrane-associated protein kinase C at lower levels than required for phosphatidylinositol kinase activation and neoplastic transformation.
- Author
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Marcellus R, Whitfield JF, and Raptis L
- Subjects
- 1-Phosphatidylinositol 4-Kinase, Animals, Cell Line, Cell Line, Transformed, Cell Membrane enzymology, Cell Membrane ultrastructure, Cell Transformation, Neoplastic, Enzyme Activation physiology, Membrane Proteins metabolism, Oncogene Protein pp60(v-src) physiology, Phenotype, Phosphotransferases metabolism, Protein Kinase C metabolism, Antigens, Polyomavirus Transforming physiology, Membrane Proteins physiology, Phosphotransferases physiology, Protein Kinase C physiology
- Abstract
Twelve independent rat F111 cell lines expressing the polyoma virus middle tumor antigen (mT) under control of the dexamethasone-regulatable MMTV-LTR promoter were assayed for levels of membrane-associated protein kinase C (PKC) activity. Low background levels of mT antigen expression (approximately 2%), although insufficient for transformation, triggered a dramatic increase in PKC activity. Under the same conditions, levels of the mT-associated phosphatidylinositol kinase activity were low, indicating that this kinase might be a factor limiting transformation in this cell system.
- Published
- 1991
49. Transforming signals generated by the polyoma virus tumor antigens.
- Author
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Raptis L, Marcellus RC, and Whitfield JF
- Subjects
- Animals, Cell Line, Models, Biological, Oncogene Protein pp60(v-src) metabolism, Phosphorylation, Polyomavirus immunology, Signal Transduction, Antigens, Polyomavirus Transforming genetics, Cell Transformation, Neoplastic, Polyomavirus genetics
- Abstract
The secretion of a threshold amount of SAGF can elicit one of the major features of the transformed phenotype, anchorage-independent growth. It appears that, like other cells, NIH 3T3 cells make and secrete SAGF, but not enough to enable them to proliferate in soft agar. The stream of signals from polyoma virus MTAg:pp60c-src:PI-kinase complexes attached to the inner surface of the cell membrane is not enough to raise SAGF secretion to the threshold level for agar growth, but these signals can powerfully enhance the responsiveness to added SAGF. Only when NIH 3T3 cells express all three polyoma T antigens do they secrete enough SAGF and become responsive enough to the factor to form colonies in soft agar. This is in contrast to F111 cells which produce adequate amounts of, and respond to, SAGF after MTAg expression alone. The reasons for this difference remain to be investigated. Obviously, factors expressed during the course of the spontaneous establishment are different for these two lines and they affect the cells' response to MTAg. Clearly, knowing how polyoma virus transforms cells will require a deeper understanding of the deregulation of membrane signaling enzymes by the viral MTAg and the identification and characterization of the autocrine SAGF's that mediate at least part of the neoplastic response to the viral signals.
- Published
- 1990
- Full Text
- View/download PDF
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