Azacitidine versus decitabine in patients with refractory anemia with excess blast—Results of multicenter study

Targeting DNA methyltransferases for cancer therapy

DNA methyltransferases (DNMTs) play a crucial role in genomic DNA methylation. In mammals, DNMTs regulate the dynamic patterns of DNA methylation in embryonic and adult cells. Abnormal functions of DNMTs are often indicative of cancers, including overall hypomethylation and partial hypermethylation of tumor suppressor genes (TSG), which accelerate the malignancy of tumors, worsen the condition of patients, and significantly exacerbate the difficulty of cancer treatment. Currently, nucleoside DNMT inhibitors such as Azacytidine and Decitabine have been approved by the FDA and EMA for the treatment of acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), and myelodysplastic syndrome (MDS). Therefore, targeting DNMTs is a very promising anti-tumor strategy. This review mainly summarizes the therapeutic effects of DNMT inhibitors on cancers. It aims to provide more possibilities for the treatment of cancers by discovering more DNMT inhibitors with high activity, high selectivity, and good drug-like properties in the future.

Glutathione promotes the synergistic effects of venetoclax and azacytidine against myelodysplastic syndrome‑refractory anemia by regulating the cell cycle

Azacitidine is a DNA methyltransferase inhibitor that has been used as a singular agent for the treatment of myelodysplastic syndrome-refractory anemia with excess blast-1 and -2 (MDS-RAEB I/II). However, recurrence and overall response rates following this treatment remain unsatisfactory. The combination of azacitidine and venetoclax has been used for the clinical treatment of a variety of hematological diseases due to the synergistic killing effect of the two drugs. Venetoclax is a BCL-2 inhibitor that can inhibit mitochondrial metabolism. In addition, azacitidine has been shown to reduce the levels of myeloid cell leukemia 1 (MCL-1) in acute myeloid leukemia cells. MCL-1 is an anti-apoptotic protein and a potential source of resistance to venetoclax. However, the mechanism underlying the effects of combined venetoclax and azacitidine treatment remains to be fully elucidated. In the present study, the molecular mechanism underlying the impact of venetoclax on the efficacy of azacitidine was investigated by examining its effects on cell cycle progression. SKM-1 cell lines were treated in vitro with 0-2 µM venetoclax and 0-4 µM azacytidine. After 24, 48 and 72 h of treatment, the impact of the drugs on the cell cycle was assessed by flow cytometry. Following drug treatment, changes in cellular glutamine metabolism pathways was analyzed using western blotting (ATF4, CHOP, ASCT2, IDH2 and RB), quantitative PCR (ASCT2 and IDH2), liquid chromatography-mass spectrometry (α-KG, succinate and glutathione) and ELISA (glutamine and glutaminase). Venetoclax was found to inhibit mitochondrial activity though the alanine-serine-cysteine transporter 2 (ASCT2) pathway, which decreased glutamine uptake. Furthermore, venetoclax partially antagonized the action of azacitidine through this ASCT2 pathway, which was reversed by glutathione (GSH) treatment. These results suggest that GSH treatment can potentiate the synergistic therapeutic effects of venetoclax and azacitidine combined treatment on a myelodysplastic syndrome-refractory anemia cell line at lower concentrations.

Pyrazolyl-s-triazine with indole motif as a novel of epidermal growth factor receptor/cyclin-dependent kinase 2 dual inhibitors

A series of pyrazolyl-s-triazine compounds with an indole motif was designed, synthesized, and evaluated for anticancer activity targeting dual EGFR and CDK-2 inhibitors. The compounds were tested for cytotoxicity using the MTT assay. Compounds 3h, 3i, and 3j showed promising cytotoxic activity against two cancer cell lines, namely A549, MCF-7, and HDFs (non-cancerous human dermal fibroblasts). Compound 3j was the most active candidate against A549, with an IC₅₀ of 2.32 ± 0.21 μM. Compounds 3h and 3i were found to be the most active hybrids against MCF-7 and HDFs, with an IC₅₀ of 2.66 ± 0.26 μM and 3.78 ± 0.55 μM, respectively. Interestingly, 3i showed potent EGFR inhibition, with an IC₅₀ of 34.1 nM compared to Erlotinib (IC₅₀ = 67.3 nM). At 10 μM, this candidate caused 93.6% and 91.4% of EGFR and CDK-2 inhibition, respectively. Furthermore, 3i enhanced total lung cancer cell apoptosis 71.6-fold (43.7% compared to 0.61% for the control). Given the potent cytotoxicity exerted by 3i through apoptosis-mediated activity, this compound emerges as a promising target-oriented anticancer agent.

Solute Carrier Nucleoside Transporters in Hematopoiesis and Hematological Drug Toxicities: A Perspective

Simple Summary

Anticancer nucleoside analogs are promising treatments that often result in damaging toxicities and therefore ineffective treatment. Mechanisms of this are not well-researched, but cellular nucleoside transport research in mice might provide additional insight given transport’s role in mammalian hematopoiesis. Cellular nucleoside transport is a notable component of mammalian hematopoiesis due to how mutations within it relate to hematological abnormities. This review encompasses nucleoside transporters, focusing on their inherent properties, hematopoietic role, and their interplay in nucleoside drug treatment side effects. We then propose potential mechanisms to explain nucleoside transport involvement in blood disorders. Finally, we point out and advocate for future research areas that would improve therapeutic outcomes for patients taking nucleoside analog therapies.

Abstract

Anticancer nucleoside analogs produce adverse, and at times, dose-limiting hematological toxicities that can compromise treatment efficacy, yet the mechanisms of such toxicities are poorly understood. Recently, cellular nucleoside transport has been implicated in normal blood cell formation with studies from nucleoside transporter-deficient mice providing additional insights into the regulation of mammalian hematopoiesis. Furthermore, several idiopathic human genetic disorders have revealed nucleoside transport as an important component of mammalian hematopoiesis because mutations in individual nucleoside transporter genes are linked to various hematological abnormalities, including anemia. Here, we review recent developments in nucleoside transporters, including their transport characteristics, their role in the regulation of hematopoiesis, and their potential involvement in the occurrence of adverse hematological side effects due to nucleoside drug treatment. Furthermore, we discuss the putative mechanisms by which aberrant nucleoside transport may contribute to hematological abnormalities and identify the knowledge gaps where future research may positively impact treatment outcomes for patients undergoing various nucleoside analog therapies.

Platelet Doubling After First Decitabine Cycle Predicts Response and Survival of Myelodysplastic Syndrome Patients

OBJECTIVE

Although the effect of decitabine on myelodysplastic syndrome (MDS) has been demonstrated, merely a proportion of patients respond to therapy, and no well-recognized predictors have been identified. This study was conducted to investigate the effectiveness of decitabine in real-world clinical practice, and determine the predictive factors of response and overall survival (OS) in MDS patients.

METHODS

Clinical and pathological data were collected from 94 patients and analyzed. These patients were reclassified according to the 2016 World Health Organization classification criteria, and restratified by International Prognostic Scoring System prognostic scores. The response evaluation was performed according to the 2006 modified International Working Group response criteria.

RESULTS

In this study, 62% of patients responded to decitabine. Among these patients, 15 patients (16%) obtained complete remission (CR), 15 patients (16%) obtained marrow CR with hematologic improvement (HI), 20 patients (21%) obtained marrow CR without HI, and 8 patients (9%) only obtained HI, and no patient botained partial remission. The OS of the responders was significantly longer than that of non-responders (67 months vs. 7 months, P<0.001). The OS in patients with and without platelet doubling was significantly different in both the low/intermediate and high/very high risk groups (P=0.0398 and P=0.0330). The multivariate analysis revealed that platelet doubling after the first decitabine cycle is an independent predictor of response and OS in MDS patients (P=0.002 and P=0.008).

CONCLUSION

Decitabine is effective for treating MDS patients in real-world clinical practice. Furthermore, platelet doubling after the first decitabine cycle can be used as a predictor of response and survival in MDS patients.

Comparison Between Decitabine and Azacitidine for Patients With Acute Myeloid Leukemia and Higher-Risk Myelodysplastic Syndrome: A Systematic Review and Network Meta-Analysis

Background: The hypomethylating agents (HMAs) azacitidine (AZA) and decitabine (DAC) have been widely used in patients with acute myeloid leukemia (AML) and higher-risk myelodysplastic syndrome (HR-MDS). However, few direct clinical trials have been carried out to compare the efficacy and adverse events (AEs) between these two agents. The clinical choice between them is controversial. A systematic review and network meta-analysis (NMA) was performed to compare the efficacy, safety, and survival of DAC and AZA in AML and HR-MDS patients.

Methods: We systematically searched MEDLINE, Embase, Web of Science, and Cochrane Library through March 15, 2021. Randomized controlled trials (RCTs) on AML or HR-MDS patients comparing the efficacy and safety between DAC and AZA or comparing one of HMAs to conventional care regimens (CCR) were selected.

Results: Eight RCTs (n = 2,184) were identified in the NMA. Four trials compared AZA to CCR, and four compared DAC to CCR. Direct comparisons indicated that, compared to CCR, both AZA and DAC were associated with higher overall response (OR) rate (AZA vs. CCR: relative risk (RR) = 1.48, 95% CI 1.05–2.1; DAC vs. CCR: RR = 2.14, 95% CI 1.21–3.79) and longer overall survival (OS) (AZA vs. CCR: HR = 0.64, 95% CI 0.50–0.82; DAC vs. CCR: HR = 0.84, 95% CI 0.72–0.98), and AZA showed higher rate of complete remission with incomplete blood count recovery (CRi) (HR = 2.52, 95% CI 1.27–5). For the indirect method, DAC showed a higher complete remission (CR) rate than AZA in patients with both AML (RR = 2.28, 95% CI 1.12–4.65) and MDS (RR = 7.57, 95% CI 1.26–45.54). Additionally, DAC significantly increased the risk of 3/4 grade anemia (RR = 1.61, 95% CI: 1.03–2.51), febrile neutropenia (RR = 4.03, 95% CI: 1.41–11.52), and leukopenia (RR = 3.43, 95% CI 1.64–7.16) compared with AZA. No statistical significance was found for the other studied outcomes.

Conclusion: Compared to CCR, both AZA and DAC can promote outcomes in patients with AML and HR-MDS. DAC showed higher efficacy especially CR rate than AZA (low-certainty evidence), while AZA experienced lower frequent grade 3/4 cytopenia than patients receiving DAC treatment.

Synthesis of New 1,3,5-Triazine-Based 2-Pyrazolines as Potential Anticancer Agents

A new series of 1,3,5-triazine-containing 2-pyrazoline derivatives (8⁻11)a⁻g was synthesized by cyclocondensation reactions of [(4,6-bis((2-hydroxyethyl)amino)-1,3,5-triazin-2-yl)amine]chalcones 7a⁻g with hydrazine hydrate and derivatives. Chalcones 7a⁻g were obtained by Claisen-Schmidt condensation between aromatic aldehydes and triazinic derivative 5, which was synthesized in high yield by a microwave-assisted reaction. Seventeen of the synthesized compounds were selected and tested by the US National Cancer Institute (NCI) for their anticancer activity against 58 different human tumor cell lines. Compounds 7g and 10d,e,g showed important GI50 values ranging from 0.569 to 16.6 µM and LC50 values ranging from 5.15 to >100 µM.

DNA Methylation Events as Markers for Diagnosis and Management of Acute Myeloid Leukemia and Myelodysplastic Syndrome

During the onset and progression of hematological malignancies, many changes occur in cellular epigenome, such as hypo- or hypermethylation of CpG islands in promoter regions. DNA methylation is an epigenetic modification that regulates gene expression and is a key event for tumorigenesis. The continuous search for biomarkers that signal early disease, indicate prognosis, and act as therapeutic targets has led to studies investigating the role of DNA in cancer onset and progression. This review focuses on DNA methylation changes as potential biomarkers for diagnosis, prognosis, response to treatment, and early toxicity in acute myeloid leukemia and myelodysplastic syndrome. Here, we report that distinct changes in DNA methylation may alter gene function and drive malignant cellular transformation during several stages of leukemogenesis. Most of these modifications occur at an early stage of disease and may predict myeloid/lymphoid transformation or response to therapy, which justifies its use as a biomarker for disease onset and progression. Methylation patterns, or its dynamic change during treatment, may also be used as markers for patient stratification, disease prognosis, and response to treatment. Further investigations of methylation modifications as therapeutic biomarkers, which may correlate with therapeutic response and/or predict treatment toxicity, are still warranted.

Comparative clinical effectiveness of azacitidine versus decitabine in older patients with myelodysplastic syndromes

The hypomethylating agents (HMAs) azacitidine and decitabine are both approved for treatment of myelodysplastic syndromes (MDS) in the USA. In Europe, decitabine is not approved due to lack of survival advantage in randomized trials. The two drugs have not been compared in clinical trials. We identified patients diagnosed with MDS between 2004 and 2011 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database in the USA who received ≥ 10 doses of either HMA. We estimated survival from HMA initiation with Kaplan-Meier methods and used multivariate Cox proportional hazards models to adjust for covariates. Analyses controlled for histological subtype and we conducted a subset analysis limited to patients with refractory anaemia with excess blasts (RAEB). In 2025 HMA-treated patients, median survival was 15 months with no difference in survival based on the HMA received in adjusted analysis (decitabine versus azacitidine, hazard ratio = 1·06, 95% confidence interval: 0·94-1·19, P = 0·37). For RAEB patients (n = 523), median survival was 12 months, with no significant difference based on HMA received. No significant survival difference was found between azacitidine and decitabine in patients with MDS, including RAEB. Importantly, population-based survival of azacitidine-treated RAEB patients was substantially shorter than in the AZA-001 clinical trial (11 versus 24·5 months).