Search

6-thioguanine (6-TG) is an antimetabolite drug of purine structure, approved by the FDA for the treatment of acute myeloid lesukemia, and it is of interest in treating other diseases. The interaction of drugs with matrices is of interest to achieving a delayed, sustained, and local release. The interaction of 6-TG with an aluminum metal-organic framework (Al-MOF) DUT-4 is studied using a novel experimental approach, namely, mechano-chemistry by liquid-assisted grinding (LAG). The bonding of 6-TG to the DUT-4 matrix in the composite (6-TG)(DUT-4) was studied using ATR-FTIR spectroscopy and XRD. This interaction involves amino groups and C and N atoms of the heterocyclic ring of 6-TG, as well as the carboxylate COO - and (Al)O-H groups of the matrix, indicating the formation of the complex. Next, an in vitro delayed release of 6-TG was studied from composite powder versus pure 6-TG in phosphate buffered saline (PBS) at 37 °C. Herein, an automated drug dissolution apparatus with an autosampler was utilized, and the molar concentration of the released 6-TG was determined using an HPLC-UV analysis. Pure 6-TG shows a quick (<300 min) dissolution, while the composite gives the dissolution of non-bonded 6-TG, followed by a significantly (factor 6) slower release of the bonded drug. Each step of the release follows the kinetic pseudo-first-order rate law with distinct rate constants. Then, a pharmaceutical shaped body was prepared from the composite, and it yields a significantly delayed release of 6-TG for up to 10 days; a sustained release is observed with the 6-TG concentration being within the therapeutically relevant window. Finally, the composite shows a time-dependent (up to 9 days) stronger inhibition of leukemia MV-4-11 cell colonies than 6-TG.

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease without meaningful therapeutic options beyond the first salvage therapy. Targeting PDAC metabolism through amino acid restriction has emerged as a promising new strategy, with asparaginases, enzymes that deplete plasma glutamine and asparagine, reaching clinical trials. In this study, we investigated the anti-PDAC activity of the asparaginase formulation Pegcrisantaspase (PegC) alone and in combination with standard-of-care chemotherapeutics., Methods: Using mouse and human PDAC cell lines, we assessed the impact of PegC on cell proliferation, cell death, and cell cycle progression. We further characterized the in vitro effect of PegC on protein synthesis as well as the generation of reactive oxygen species and levels of glutathione, a major cellular antioxidant. Additional cell line studies examined the effect of the combination of PegC with standard-of-care chemotherapeutics. In vivo, the tolerability and efficacy of PegC, as well as the impact on plasma amino acid levels, was assessed using the C57BL/6-derived KPC syngeneic mouse model., Results: Here we report that PegC demonstrated potent anti-proliferative activity in a panel of human and murine PDAC cell lines. This decrease in proliferation was accompanied by inhibited protein synthesis and decreased levels of glutathione. In vivo, PegC was tolerable and effectively reduced plasma levels of glutamine and asparagine, leading to a statistically significant inhibition of tumor growth in a syngeneic mouse model of PDAC. There was no observable in vitro or in vivo benefit to combining PegC with standard-of-care chemotherapeutics, including oxaliplatin, irinotecan, 5-fluorouracil, paclitaxel, and gemcitabine. Notably, PegC treatment increased tumor expression of asparagine and serine biosynthetic enzymes., Conclusions: Taken together, our results demonstrate the potential therapeutic use of PegC in PDAC and highlight the importance of identifying candidates for combination regimens that could improve cytotoxicity and/or reduce the induction of resistance pathways., (© 2024. The Author(s).)

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy characterized by disrupted blood cell production and function. Recent investigations have highlighted the potential of targeting glutamine metabolism as a promising therapeutic approach for AML. Asparaginases, enzymes that deplete circulating glutamine and asparagine, are approved for the treatment of acute lymphoblastic leukemia, but are also under investigation in AML, with promising results. We previously reported an elevation in plasma serine levels following treatment with Erwinia -derived asparaginase (also called crisantaspase). This led us to hypothesize that AML cells initiate the de novo serine biosynthesis pathway in response to crisantaspase treatment and that inhibiting this pathway in combination with crisantaspase would enhance AML cell death. Here we report that in AML cell lines, treatment with the clinically available crisantaspase, Rylaze, upregulates the serine biosynthesis enzymes phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase (PSAT1) through activation of the Amino Acid Response (AAR) pathway, a cellular stress response mechanism that regulates amino acid metabolism and protein synthesis under conditions of nutrient limitation. Inhibition of serine biosynthesis through CRISPR- Cas9 -mediated knockout of PHGDH resulted in a ~250-fold reduction in the half-maximal inhibitory concentration (IC 50 ) for Rylaze, indicating heightened sensitivity to crisantaspase therapy. Treatment of AML cells with a combination of Rylaze and a small molecule inhibitor of PHGDH (BI4916) revealed synergistic anti-proliferative effects in both cell lines and primary AML patient samples. Rylaze-BI4916 treatment in AML cell lines led to the inhibition of cap-dependent mRNA translation and protein synthesis, as well as a marked decrease in intracellular glutathione levels, a critical cellular antioxidant. Collectively, our results highlight the clinical potential of targeting serine biosynthesis in combination with crisantaspase as a novel therapeutic strategy for AML., Competing Interests: AE has received research grants from Jazz Pharmaceuticals, NewLink Genetics, Amgen, and Servier Pharmaceuticals. AE is a global oncology advisory board member for Amgen and has served as an advisory board member for Genentech and Servier. AE and RL are Co-Founders and Scientific Advisors for KinaRx, Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hameed, Bollino, Shetty, Carter-Cooper, Lapidus and Emadi.)

The impact of asparaginases on plasma asparagine and glutamine is well established. However, the effect of asparaginases, particularly those derived from Erwinia chrysanthemi (also called crisantaspase), on circulating levels of other amino acids is unknown. We examined comprehensive plasma amino acid panel measurements in healthy immunodeficient/immunocompetent mice as well as in preclinical mouse models of acute myeloid leukemia (AML) and pancreatic ductal adenocarcinoma (PDAC) using long-acting crisantaspase, and in an AML clinical study (NCT02283190) using short-acting crisantaspase. In addition to the expected decrease of plasma glutamine and asparagine, we observed a significant increase in plasma serine and glycine post-crisantaspase. In PDAC tumors, crisantaspase treatment significantly increased expression of serine biosynthesis enzymes. We then systematically reviewed clinical studies using asparaginase products to determine the extent of plasma amino acid reporting and found that only plasma levels of glutamine/glutamate and asparagine/aspartate were reported, without measuring other amino acid changes post-asparaginase. To the best of our knowledge, we are the first to report comprehensive plasma amino acid changes in mice and humans treated with asparaginase. As dysregulated serine metabolism has been implicated in tumor development, our findings offer insights into how leukemia/cancer cells may potentially overcome glutamine/asparagine restriction, which can be used to design future synergistic therapeutic approaches., Competing Interests: AE has received research grants from Jazz Pharmaceuticals, Amgen, NewLinks, and Servier. AE is a global oncology advisory board member for Amgen and has served as an advisory board member for Genentech, Servier, Kite Pharma, and Secura Bio. AE and RL are Co-Founders and Scientific Advisors for KinaRx, Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bollino, Claiborne, Hameed, Ma, Tighe, Carter-Cooper, Lapidus, Strovel and Emadi.)

Objectives: To identify the most effective PI3K and EGFR inhibitors in HPV-positive head and neck squamous cell carcinoma (HNSCC) and investigate the efficacy of a combination of an ErbB family kinase inhibitor and a PI3K inhibitor to inhibit cell proliferation of HPV-positive HNSCC., Materials and Method: HPV-positive HNSCC cell lines were treated with the FDA approved ErbB kinase inhibitor, Afatinib or FDA-approved PI3K inhibitor, Copanlisib, alone or in combination, and phosphorylation and total protein levels of cells were assessed by Western blot analysis.Cell proliferation and apoptosis were examined by MTS assay, flow cytometry, and Western blots, respectively., Results: Copanlisib more effectively inhibited cell proliferation in comparison to other PI3K inhibitors tested. HPV-positive HNSCC cells differentially responded to cisplatin, Afatinib, or Copanlisib. The combination of Afatinib and Copanlisib more effectively suppressed cell proliferation and induced apoptosis compared to either treatment alone. Mechanistically, the combination of Afatinib and Copanlisib completely blocked phosphorylation of EGFR, HER2, HER3, and Akt as well as significantly decreased the HPV E7 expression compared to either treatment alone., Conclusion: Afatinib and Copanlisib more effectively suppress cell proliferation and survival of HPV-positive HNSCC in comparison to either treatment alone., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: The clinical outcomes of patients with Acute Myeloid Leukemia (AML) remain unsatisfactory. Therefore the development of more efficacious and better-tolerated therapy for AML is critical. We have previously reported anti-leukemic activity of synthetic halohydroxyl dimeric naphthoquinones (BiQ) and aziridinyl BiQ., Objective: This study aimed to improve the potency and bioavailability of BiQ compounds and investigate antileukemic activity of the lead compound in vitro and a human AML xenograft mouse model., Methods: We designed, synthesized, and performed structure-activity relationships of several rationally designed BiQ analogues with amino alcohol functional groups on the naphthoquinone core rings. The compounds were screened for anti-leukemic activity and the mechanism as well as in vivo tolerability and efficacy of our lead compound was investigated., Results: We report that a dimeric naphthoquinone (designated BaltBiQ) demonstrated potent nanomolar anti-leukemic activity in AML cell lines. BaltBiQ treatment resulted in the generation of reactive oxygen species, induction of DNA damage, and inhibition of indoleamine dioxygenase 1. Although BaltBiQ was tolerated well in vivo, it did not significantly improve survival as a single agent, but in combination with the specific Bcl-2 inhibitor, Venetoclax, tumor growth was significantly inhibited compared to untreated mice., Conclusion: We synthesized a novel amino alcohol dimeric naphthoquinone, investigated its main mechanisms of action, reported its in vitro anti-AML cytotoxic activity, and showed its in vivo promising activity combined with a clinically available Bcl-2 inhibitor in a patient-derived xenograft model of AML., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Complex karyotype acute myeloid leukemia (CK-AML) has a dismal outcome with current treatments, underscoring the need for new therapies. Here, we report synergistic anti-leukemic activity of the BCL-2 inhibitor venetoclax (Ven) and the asparaginase formulation Pegylated Crisantaspase (PegC) in CK-AML in vitro and in vivo. Ven-PegC combination inhibited growth of multiple AML cell lines and patient-derived primary CK-AML cells in vitro. In vivo, Ven-PegC showed potent reduction of leukemia burden and improved survival, compared with each agent alone, in a primary patient-derived CK-AML xenograft. Superiority of Ven-PegC, compared to single drugs, and, importantly, the clinically utilized Ven-azacitidine combination, was also demonstrated in vivo in CK-AML. We hypothesized that PegC-mediated plasma glutamine depletion inhibits 4EBP1 phosphorylation, decreases the expression of proteins such as MCL-1, whose translation is cap dependent, synergizing with the BCL-2 inhibitor Ven. Ven-PegC treatment decreased cellular MCL-1 protein levels in vitro by enhancing eIF4E-4EBP1 interaction on the cap-binding complex via glutamine depletion. In vivo, Ven-PegC treatment completely depleted plasma glutamine and asparagine and inhibited mRNA translation and cellular protein synthesis. Since this novel mechanistically-rationalized regimen combines two drugs already in use in acute leukemia treatment, we plan a clinical trial of the Ven-PegC combination in relapsed/refractory CK-AML.

We explored the role of the transcription factor, NF-κB, and its upstream kinase IKKβ in regulation of migration, invasion, and metastasis of cisplatin-resistant head and neck squamous cell carcinoma (HNSCC). We showed that cisplatin-resistant HNSCC cells have a stronger ability to migrate and invade, as well as display higher IKKβ/NF-κB activity compared to their parental partners. Importantly, we found that knockdown of IKKβ, but not NF-κB, dramatically impaired cell migration and invasion in these cells. Consistent with this, the IKKβ inhibitor, CmpdA, also inhibited cell migration and invasion. Previous studies have already shown that N-Cadherin, an epithelial-mesenchymal transition (EMT) marker, and IL-6, a pro-inflammatory cytokine, play important roles in regulation of HNSCC migration, invasion, and metastasis. We found that cisplatin-resistant HNSCC expressed higher levels of N-Cadherin and IL-6, which were significantly inhibited by CmpdA. More importantly, we showed that CmpdA treatment dramatically abated cisplatin-resistant HNSCC cell metastasis to lungs in a mouse model. Our data demonstrated the crucial role of IKKβ in control of migration, invasion, and metastasis, and implicated that targeting IKKβ may be a potential therapy for cisplatin-resistant metastatic HNSCC.

Aim: Mutated or overexpressed FLT3 drives about 30% of reported acute myeloid leukemia (AML). Currently, FLT3 inhibitors have shown durable clinical responses but a complete remission of AML with FLT3 inhibitors remains elusive due to mutation-driven resistance mechanisms. The development of FLT3 inhibitors that also target other downstream oncogenic kinases may combat the resistance mechanism., Results: 4-substituted aminoisoquinoline benzamides potently inhibit Src-family kinases and FLT3, including secondary mutations, such as FLT3D835. Modifications of aminoisoquinoline benzamide to aminoquinoline or aminoquinazoline abrogated FLT3 and Src-family kinase binding., Conclusion: The lead aminoisoquinolines potently inhibited FLT3-driven AML cell lines, MV4-11 and MOLM-14. These aminoisoquinoline benzamides represent new kinase scaffolds with high potential to be translated into anticancer agents.

Acute myeloid leukemia (AML) is an aggressive malignancy with only a handful of therapeutic options. About 30% of AML patients harbor mutated FLT3 kinase, and thus, this cancer-driver has become a hotly pursued AML target. Herein we report a new class of FLT3 inhibitors, which potently inhibit the proliferation of acute myeloid leukemia (AML) cells at nanomolar concentrations.

G-quadruplex ligands have been touted as potential anticancer agents, however, none of the reported G-quadruplex-interactive small molecules have gone past phase II clinical trials. Recently it was revealed that diminazene (berenil, DMZ) actually binds to G-quadruplexes 1000 times better than DNA duplexes, with dissociation constants approaching 1 nM. DMZ however does not have strong anticancer activities. In this paper, using a panel of biophysical tools, including NMR, FRET melting assay and FRET competition assay, we discovered that monoamidine analogues of DMZ bearing alkyne substitutes selectively bind to G-quadruplexes. The lead DMZ analogues were shown to be able to target c-MYC G-quadruplex both in vitro and in vivo. Alkyne DMZ analogues display respectable anticancer activities (single digit micromolar GI50) against ovarian (OVCAR-3), prostate (PC-3) and triple negative breast (MDA-MB-231) cancer cell lines and represent interesting new leads to develop anticancer agents., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

The incidence of acute myeloid leukemia (AML) is rising and the outcome of current therapy, which has not changed significantly in the last 40 years, is suboptimal. Cellular oxidative state is a credible target to selectively eradicate AML cells, because it is a fundamental property of each cell that is sufficiently different between leukemic and normal cells, yet its aberrancy shared among different AML cells. To this end, we tested whether a short-time treatment of AML cells, including cells with FLT3-ITD mutation, with sub-lethal dose of dichloroacetate (DCA) (priming) followed by pharmacologic dose of arsenic trioxide (ATO) in presence of low-dose DCA could produce insurmountable level of oxidative damage that kill AML cells. Using cellular cytotoxicity, apoptotic and metabolic assays with both established AML cell lines and primary AML cells, we found that priming with DCA significantly potentiated the cytotoxicity of ATO in AML cells in a synergistic manner. The combination decreased the mitochondrial membrane potential as well as expression of Mcl-1 and GPx in primary AML cells more than either drug alone. One patient with AML whose disease was refractory to several lines of prior treatments was treated with this combination, and tolerated it well. These data suggest that targeting cellular redox balance in leukemia may provide a therapeutic option for AML patients with relapsed/refractory disease., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Mutations in IDH1 and IDH2 occur in 15-20% of AML cases, resulting in the production of 2-hydroxyglutarate, which promotes aberrant hypermethylation of DNA in leukemic cells. Although these mutations have been shown to have prognostic implications for patients with AML, optimal treatment strategies have yet to be defined. We retrospectively identified forty-two patients with AML treated with DNA methyltransferase inhibitors (DNMTIs) decitabine (n = 36) or azacitidine (n = 6) and performed analysis of stored samples for the presence of IDH1 and IDH2 mutations. Of the forty-two samples analyzed, seven (16.7%) had IDH mutations. Thirteen patients (31%) achieved remission [(complete remission (CR)/complete remission with incomplete count recovery (CRi)/partial response (PR)] after treatment with a DNMTI, five of seven (71.4%) with IDH mutations and eight of thirty-five (22.9%) without IDH mutations (P = 0.01). When adjusted for age at diagnosis, sex, bone marrow blast percentage and cytogenetic, the odds of achieving response after administration of a DNMTI among patients with an IDH mutation was 14.2 when compared to patients without an IDH mutation (95%CI: 1.3-150.4). IDH1 and IDH2 mutations may predict a favorable response to DNMTI in patients with AML., (© 2015 Wiley Periodicals, Inc.)