Hypomethylating Agents Research Articles

The prognostic significance of genetics in acute myeloid leukemia under venetoclax-based treatment.

Acute myeloid leukemia (AML) is the most prevalent hematologic malignancy in adults. In 2022, the European LeukemiaNet (ELN) has updated its prognostic system that incorporates cytogenetics and molecular genetics based on data from patients undergoing intensive chemotherapy (IC). Recently, a risk stratification framework has been established for hypomethylating agents (HMA)-based low-intensity treatment (LIT) to fill the gaps in stratification for this treatment modality, but this needs further refinement. Venetoclax (VEN), a BH3 mimetic, targets BCL-2 to modulate apoptosis and metabolism in AML cells. Its combination with HMA or low-dose cytarabine (LDAC) has been shown to enhance the response rates and prolong the survival outcomes of older or unfit patients with AML. In this review, we delved into the prognostic significance of FLT3-ITD and IDH mutations when used in combination with VEN and HMA, as well as in conjunction with their specific inhibitors. We also explored the role of VEN in NPM1-mutated AML and its efficacy in splicing factor mutations AML. Additionally, we examined the response rates and survival outcomes of CBF-AML when treated with a VEN-based regimen. Moving forward, it is imperative that risk stratification for LIT becomes more nuanced to better align with the requirements of personalized diagnosis and treatment strategies.

Injectable Autocatalytic Hydrogel Triggers Pyroptosis to Stimulate Anticancer Immune Response for Preventing Postoperative Tumor Recurrence.

Modulating immunosuppression while eliminating residual microscopic tumors is critical for inhibiting the postoperative recurrence of triple-negative breast cancer (TNBC). Although immunotherapy has shown potential in achieving this goal, due to multiple immunosuppression and poor immunogenicity of apoptosis, a satisfactory anti-recurrence effect still faces the challenge. Herein, an injectable hydrogel-encapsulated autocatalytic copper peroxide (CP@Gel) therapeutic platform is designed and combine it with the clinical-grade DNA methyltransferase inhibitor decitabine (DAC) to effectively inhibit TNBC growth and postoperative recurrence via pyroptosis, killing residual cancer cells that bypass apoptosis resistance while also improving immunogenicity and modulating immunosuppression to achieve an intense anti-tumor immune response. Following injection of the CP@Gel, the sustained release of CP leads to the autocatalytic generation of reactive oxygen species, resulting in caspase-3 activation, and the pre-administered DAC inhibits the methylation of Gsdme to elevate the GSDME protein levels, leading to intense pyroptosis and anti-tumor immune responses. The in vivo results show a 67% elimination of local tumor recurrence via treatment with DAC+CP@Gel, suggesting the successful integration of sustained drug release with autocatalysis and epigenetic modification. The results thus suggest great potential for pyroptosis-based and injectable hydrogel-aided strategies for preventing the postoperative recurrence of TNBC.

Comprehensive review and updated analysis of DNA methylation in hepatocellular carcinoma: From basic research to clinical application.

Hepatocellular carcinoma (HCC) is a primary malignant tumour, ranking second in global mortality rates and posing significant health threats. Epigenetic alterations, particularly DNA methylation, have emerged as pivotal factors associated with HCC diagnosis, therapy, prognosis and malignant progression. However, a comprehensive analysis of the DNA methylation mechanism driving HCC progression and its potential as a therapeutic biomarker remains lacking. This review attempts to comprehensively summarise various aspects of DNA methylation, such as its mechanism, detection methods and biomarkers aiding in HCC diagnosis, treatment and prognostic assessment of HCC. It also explores the role of DNA methylation in regulating HCC's malignant progression and sorafenib resistance, alongside elaborating the therapeutic effects of DNA methyltransferase inhibitors on HCC. A detailed examination of these aspects underscores the significant research on DNA methylation in tumour cells to elucidate malignant progression mechanisms, identify diagnostic markers and develop new tumour-specific inhibitors for HCC. KEY POINTS: A comprehensive summary of various aspects of DNA methylation, such as its mechanism, detection methods and biomarkers aiding in diagnosis and treatment. The role of DNA methylation in regulating hepatocellular carcinoma's (HCC) malignant progression and sorafenib resistance, alongside elaborating therapeutic effects of DNA methyltransferase inhibitors. Deep research on DNA methylation is critical for discovering novel tumour-specific inhibitors for HCC.

Azacytidine treatment affects the methylation pattern of genomic and cell-free DNA in uveal melanoma cell lines

BackgroundUveal melanoma (UM) is the most common primary intraocular tumour in adults, and approximately 50% of patients will develop metastasis. Epigenetic changes are a major factor in cancer progression. We aimed to determine whether methylation profiles could be altered using a DNA methyltransferase (DNMT) inhibitor in UM cell lines.MethodsFour primary and metastatic UM cell lines were treated with azacytidine and analysed for cell proliferation, colony formation, and BAP1 protein expression. Genomic and cell-free (cf)DNA methylation were compared.ResultsIn all cell lines, azacytidine treatment resulted in dose-dependent effects on proliferation, colony formation, and radiosensitivity. Methylation profiling revealed differences in methylation between cell lines according to BAP1 expression. Matched primary and metastatic cell lines showed very similar patterns. Alterations were seen in pathways known to be important in UM progression, such as PI3K/Akt and MAPK signaling, and in pathways involved in cancer progression, such as regulation of stemlike potential, cell motility, and invasion. These changes were maintained in genomic and cell-free DNA.ConclusionsThis data suggests that DNMT inhibitors cause changes in UM cells that are maintained in cfDNA. The results suggest that targeting methylation in UM treatment and monitoring response to treatment using cfDNA methylation could be a valuable tool.

Triggering Pyroptosis by Doxorubicin-Loaded Multifunctional Nanoparticles in Combination with Decitabine for Breast Cancer Chemoimmunotherapy.

Pyroptosis, a form of programmed cell death, holds great promise for breast cancer treatment. However, the downregulation of gasdermin E (GSDME) limits the effectiveness of pyroptosis. To address this challenge, we developed a folic acid-modified and glutathione/reactive oxygen species dual-responsive nanocarrier (FPSD NPs) for the targeted delivery of doxorubicin (DOX). Through the combination with DNA methyltransferase inhibitor decitabine (DAC), the GSDME protein expression was significantly increased in 4T1 cells, resulting in cell swelling and ballooning, which are characteristic features of pyroptosis. In vivo experiments further demonstrated the antitumor efficacy of DAC + DOX@FPSD NPs, and the 4T1-bearing mice treated with DAC + DOX@FPSD NPs exhibited reduced tumor volumes, minimized tumor weights, decreased Ki67-positive cells, increased TUNEL apoptosis ratios, and pronounced lesions in H&E staining. Furthermore, DAC + DOX@FPSD NP treatment could promote pyroptosis-associated antitumor immunity, as evidenced by the increased presence of CD3+, CD4+, and CD8+ T cells, heightened secretion of tumor necrosis factor-α and interferon-γ, elevated high-mobility group box-1 levels, and enhanced calreticulin exposure. The FPSD nanocarrier developed in this study had favorable stability, active targeting ability, biocompatibility, and controlled release properties, and the DAC + DOX@FPSD NPs represented an approach to antitumor therapy by inducing pyroptosis, which offers a promising avenue for breast cancer treatment.

HMA/VEN treatment modifications and associated outcomes in IDH-mutant AML

Hypomethylating agents (HMA) and venetoclax (VEN) are commonly used in patients with IDH-mutated (IDHm) acute myeloid leukemia (AML) ineligible for induction chemotherapy. While prior studies demonstrated high response and survival rates with HMA/VEN in IDHm AML, the impact of treatment modifications in real-world settings is unclear. We retrospectively reviewed 89 IDHm AML patients treated with HMA/VEN from January 2018 to June 2023. CR/CRi rates were 76% in newly diagnosed (ND) and 55% in relapsed/refractory (R/R) patients, and median overall survival was 29.2 months (ND) and 17.1 months (R/R), respectively. Treatment modifications were common. Early VEN reductions were associated with lower response rates but not worse survival. Prolonged cycles were not associated with worse response rates or survival. Significant neutropenia and ED visits or unplanned hospitalizations were considerable before and after CR/CRi, though febrile neutropenia decreased afterward. HMA/VEN is efficacious, with treatment modifications not affecting survival, though long-term toxicities are notable.

Revealing the effects of two DNA methyltransferase inhibitors on DNA methylation and carotenoid metabolism in Chlamydomonas reinhardtii by comparative transcriptome and physiological analysis

DNA methylation plays an important role in cell growth and development. However, little is known about the possible functions of DNA methylation in microalgae. Here, two DNA methyltransferase (DNMT) inhibitors (5-azacytidine and zebularine) were used to treat Chlamydomonas reinhardtii to investigate the effects of DNA methylation on microalgae. 5-Azacytidine (5-Azac) showed the promoting effects on cell growth and was benefit to the accumulation of pigments, while zebularine (Zeb) has adverse effects on the physiology of algal cells. However, the genomes of C. reinhardtii treated with two DNMT inhibitors unexpectedly showed slightly increased 5-mC levels. According to the results of transcriptome sequencing to algal cells treated with Zeb and 5-Azac, two DNMT inhibitors were found to up-regulate the transcription levels of genes involved in the cytosine methylation pathway and down-regulate genes involved in the cytosine demethylation pathway, which may result in higher 5-mC levels in genome. The increased content of carotenoids by 5-Azac may be due to the up-regulated transcription levels of carotenogenic genes. In addition, the up-regulated transcription levels of carotenoid degradation-related genes may be responsible for the reduced carotenoid content by Zeb. Finally, a carotenoid 9,10(9′,10′)-cleavage dioxygenase 1 (CrCCD1) gene was isolated from C. reinhardtii, and its important role in carotenoid degradation was demonstrated. In summary, this study revealed the physiological changes and molecular mechanisms of C. reinhardtii under the effects of two DNMT inhibitors, providing valuable information for subsequent studies on DNA methylation in microalgae.

FOXN3-AS1: A Candidate Prognostic Marker and Epigenetic Target with Immunotherapeutic Implications in Acute Myeloid Leukemia.

We focused on the FOXN3 gene and selected its antisense transcripts (FOXN3-AS1) to investigate its potential involvement in acute myeloid leukemia (AML). Several integrated multi-omics datasets have expanded the horizons of the cancer landscape. With the emergence of new high-throughput technologies, a large number of non-coding RNAs have been confirmed to be involved in the pathogenesis of different types of hematological malignancies. We conducted experimental validation using quantitative polymerase chain reaction (qPCR) with bone marrow specimens from AML patients. Then, Kaplan-Meier (KM) and Receiver Operating Characteristic (ROC) curves were used to substantiate the prognostic association between FOXN3-AS1 and AML patients within the TCGA database. Correlation between FOXN3-AS1 expression and gene mutation, immune, and immune function using Spearman correlation analysis. To explore the physical and functional interaction between FOXN3-AS1 and the DNMT1 protein, we utilized the RPISeq web tool from Iowa State University. Subsequently, we performed qPCR experiments to test the effect of 5AzaC (DNMT1 inhibitor) on FOXN3-AS1 expression AML cell lines (THP1 and OCI-AML3). We leveraged the "OncoPredict" R package in conjunction with the Genomics of Drug Sensitivity (GDSC) database to predict drug response in AML patients expressing FOXN3-AS1. We observed a significant upregulation of FOXN3-AS1 expression in AML patients compared to healthy controls using clinical samples. The TCGA database revealed an association between high FOXN3-AS1 expression and adverse prognosis. In our subsequent analysis, genes with poor prognostic implications in AML patients were exclusively identified in the FOXN3-AS1 high-expression group, further corroborating this relationship. AML patients with higher FOXN3-AS1 expression levels may respond less optimally to immunotherapy than patients with lower levels. Besides, we computationally predicted the interaction of FOXN3- AS1 and DNMT1 protein and experimentally confirmed that DNMT1i (GSK-3484862) affects the expression level of FOXN3-AS1. We also found that the chemotherapy drugs (5-Fluorouralic, Cisplatin, Dactolisib, Sapitinib, Temozolomide, Ulixertinib, Vinorelbine, Ruxolitinib, Osimertinib and Cisplatin) showed favorable responses in AML patients with high FOXN3-AS1 expression levels. Our candidate approach identifies FOXN3-AS1 as a prognostic indicator of survival in AML with a potential immune-related role. The preliminary observations we made on FOXN3-AS1/DNMT1 crosstalk warrant more in-depth invested immunotherapeutic approaches in AML.

Immune modulation and epigenetic therapies for enhanced outcome of treatment in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by the absence of human epidermal growth factor receptor 2, estrogen receptor, and progesterone receptor expression. While traditional TNBC treatment primarily relies on systemic chemotherapy, epigenetic modification has an important role in immune evasion and tumor progression. Recent classifications of TNBC into “hot” and “cold” tumors, based on immune activity and mutation burden, have revealed that poor response to immune checkpoint inhibitors (ICIs) in these tumors is due to low tumor-infiltrating lymphocytes and the presence of immunosuppressive cells. Emerging treatments such as ICIs and poly(ADP-ribose) polymerase inhibitors offer promising alternatives. The tumor microenvironment (TME) shapes immune responses in TNBC, and a limited subset of patients has shown encouraging responses to ICIs in treating TNBC at both early and advanced stages. However, combination therapies face challenges, including medication interactions and side effects. Epigenetic modulators, such as histone deacetylase and DNA methyltransferase inhibitors, also show promise in reversing epigenetic changes by enhancing anti-tumor immunity in TNBC. The frequent expression of indoleamine 2,3-dioxygenase 1 (IDO1) in TNBC, which catalyzes the conversion of tryptophan to kynurenine, contributes to immune suppression in TNBC patients. High IDO1 levels impair the tumoricidal activity of natural killer cells and correlate with poor responses to anti-PD-L1 therapy, which can be improved using IDO1 inhibitors. Targeting myeloid-derived suppressor cells, regulatory T-cells, and tumor-associated macrophage, along with utilizing epigenetic mechanisms, show promise in modulating the immunosuppressive TME in TNBC. Combining these approaches with standard therapies, along with biomarker-guided patient selection, can enhance treatment efficacy. Clinical trials and preclinical models are essential for optimizing these strategies. This study emphasizes the importance of understanding the mechanisms of modulation, tumor-immune interactions, and the potential of epigenetic therapies in improving treatment outcomes in TNBC.

Recurrent, multisystem angioedema induced by 5-azacitidine.

5-azacitidine is a hypomethylating agent (HMA) used for treating myelodysplastic syndrome (MDS) and certain myeloproliferative neoplasms (MPNs). Common side effects include myelosuppression, nausea and injection site reactions. Serious allergic reactions are rare with this class of agents. We describe a 71-year-old man with MDS/MPN who developed repeated episodes of angioedema after starting treatment with subcutaneous 5-azacitidine. Angioedema involved multiple body areas including the neck, genitalia, lower back and gastrointestinal system. Causality assessment linked this entity to 5-azacitidine via the Naranjo nomogram questionnaire, by scoring 9. 5-azacitidine was discontinued due to recurrent episodes of angioedema that occurred even after dose reduction. Steroids were helpful in terms of reversing this reaction. Afterwards, no further episodes of angioedema have been documented. The patient's thrombocytosis is currently well-controlled with low dose hydroxyurea. We report herein a unique case of recurrent, multisystem angioedema likely related to 5-azacitidine. The exact mechanism of azacitidine-induced angioedema is not currently known. Symptoms, clinical findings and timing of presentation are not always clear-cut, and it may take more than one cycle of 5-azacitidine before the diagnosis is made. Supportive and symptomatic treatment will be provided based on the severity of the reaction. Future studies may offer more insights into the mechanism underlying this rare and serious, yet intriguing side effect.

Integrated transcriptomic and proteomic analysis revealed the regulatory role of 5-azacytidine in kenaf salt stress alleviation

Salinity stress limits agricultural production. The DNA methyltransferase inhibitor, 5-azacitidine (5-azaC), plays a role in plant abiotic stress regulation, but its molecular basis in mediating salinity tolerance in kenaf remains unclear. To investigate the effects on 5-azaC on alleviating salt stress, kenaf seedlings were pre-treated with 0, 50, 100, 150, and 200 μM 5-azaC and then exposed to 150 mM NaCl in a nutrient solution. Physiological, transcriptomic, and proteomic analyses were conducted on the root system to understand the regulatory mechanism of 5-azaC (comparing 5-azaC150 and control group 5-azaC0) under salt stress. The results indicated that 5-azaC significantly mitigated salt stress in kenaf by activating the antioxidant system, reducing reactive oxygen species (ROS), and increasing starch, soluble sugars, and adenosine triphosphate (ATP) content. A total of 14,348 differentially expressed genes (DEGs) and 313 differentially abundant proteins (DAPs) were identified. Combined proteomic and transcriptomic analysis revealed 27 DEGs/DAPs, with jointly up-regulated proteins (genes) including HcTHI1, HcBGLU11, and HcCBL1, and jointly down-regulated proteins (genes) including HcGAPDH, HcSS, and HcPP2C52. Overexpression and virus-induced gene silencing (VIGS) of HcPP2C52 demonstrated its role as a negative regulator of salt tolerance. These findings provide insights into the regulatory role of 5-azaC in plant responses to abiotic stresses. SignificanceThe specific molecular mechanism by which 5-azaC affects gene expression and protein activity of kenaf has been revealed, leading to enhanced salt tolerance.

Expression, DNA methylation pattern and transcription factor EPB41L3 in gastric cancer: a study of 262 cases

PurposeDNA methylation prominently inactivates tumor suppressor genes and facilitates oncogenesis. Previously, we delineated a chromosome 18 deletion encompassing the erythrocyte membrane protein band 4.1-like 3 (EPB41L3) gene, a progenitor for the tumor suppressor that is differentially expressed in adenocarcinoma of the lung-1 (DAL-1) in gastric cancer (GC).MethodsOur current investigation aimed to elucidate EPB41L3 expression and methylation in GC, identify regulatory transcription factors, and identify affected downstream pathways. Immunohistochemistry demonstrated that DAL-1 expression is markedly reduced in GC tissues, with its downregulation serving as an independent prognostic marker.ResultsHigh-throughput bisulfite sequencing of 70 GC patient tissue pairs revealed that higher methylation of non-CpGs in the EPB41L3 promoter was correlated with more malignant tumor progression and higher-grade tissue classification. Such hypermethylation was shown to diminish DAL-1 expression, thus contributing to the malignancy of GC phenotypes. The DNA methyltransferase inhibitor 5-aza-2’-deoxycytidine (5-aza-CdR) was found to partially restore DAL-1 expression. Moreover, direct binding of the transcription factor CDC5L to the upstream region of the EPB41L3 promoter was identified via chromosome immunoprecipitation (ChIP)-qPCR and luciferase reporter assays. Immunohistochemistry confirmed the positive correlation between CDC5L and DAL-1 protein levels. Subsequent RNA-seq analysis revealed that DAL-1 significantly influences the extracellular matrix and space-related pathways. GC cell RNA-seq post-5-Aza-CdR treatment and single-cell RNA-seq data of GC tissues confirmed the upregulation of AREG and COL17A1, pivotal tumor suppressors, in response to EPB41L3 demethylation or overexpression in GC epithelial cells.ConclusionIn conclusion, this study elucidates the association between non-CpG methylation of EPB41L3 and GC progression and identifies the key transcription factors and downstream molecules involved. These findings enhance our understanding of the role of EPB41L3 in gastric cancer and provide a solid theoretical foundation for future research and potential clinical applications.

443 (PB431): A Sub Analysis of Clinical Study of Tomaralimab, a Toll-like Receptor 2 (TLR-2) Antibody, in Patients with Lower Risk Myelodysplastic Syndromes (MDS) That Have Received Prior Hypomethylating Agent (HMA) Therapy

443 (PB431): A Sub Analysis of Clinical Study of Tomaralimab, a Toll-like Receptor 2 (TLR-2) Antibody, in Patients with Lower Risk Myelodysplastic Syndromes (MDS) That Have Received Prior Hypomethylating Agent (HMA) Therapy

DNA Methyltransferase Inhibitor Alleviates Kidney Inflammation and Injury by Reversing DNA Hypermethylation-Associated Klotho Suppression in Diabetic db/db Mice

DNA Methyltransferase Inhibitor Alleviates Kidney Inflammation and Injury by Reversing DNA Hypermethylation-Associated Klotho Suppression in Diabetic db/db Mice

DNA Methyltransferase Inhibition Upregulates the Costimulatory Molecule ICAM-1 and the immunogenic phenotype of melanoma cells

DNA Methyltransferase Inhibition Upregulates the Costimulatory Molecule ICAM-1 and the immunogenic phenotype of melanoma cells

Quinoline-based compounds can inhibit diverse enzymes that act on DNA.

DNA methylation, as exemplified by cytosine-C5 methylation in mammals and adenine-N6 methylation in bacteria, is a key epigenetic process. Developing non-nucleoside inhibitors to cause DNA hypomethylation is crucial for treating various conditions without the toxicities associated with existing cytidine-based hypomethylating agents. This study characterized fifteen quinoline-based analogs, particularly compounds with additions like a methylamine (9) or methylpiperazine (11), which demonstrate similar low micromolar inhibitory potency against human DNMT1 and Clostridioides difficile CamA. These compounds (9 and 11) intercalate into CamA-bound DNA via the minor groove, causing a conformational shift that moves the catalytic domain away from the DNA. This study adds to the limited examples of DNA methyltransferases being inhibited by non-nucleotide compounds through DNA intercalation. Additionally, some quinoline-based analogs inhibit other DNA-interacting enzymes, such as polymerases and base excision repair glycosylases. Finally, compound 11 elicits DNA damage response via p53 activation in cancer cells.

Synergising hypomethylating agents with immunotherapy in renal cell carcinoma: unlocking the potential of an old classic

Synergising hypomethylating agents with immunotherapy in renal cell carcinoma: unlocking the potential of an old classic

Development of a First-in-Class DNMT1/HDAC Inhibitor with Improved Therapeutic Potential and Potentiated Antitumor Immunity.

Epigenetic therapies have emerged as a key paradigm for treating malignancies. In this study, a series of DNMT1/HDAC dual inhibitors were obtained by fusing the key pharmacophores from DNMT1 inhibitors (DNMT1i) and HDAC inhibitors (HDACi). Among them, compound (R)-23a demonstrated significant DNMT1 and HDAC inhibition both in vitro and in cells and largely phenocopied the synergistic effects of combined DNMT1i and HDACi in reactivating epigenetically silenced tumor suppressor genes (TSGs). This translated into a profound tumor growth inhibition (TGI = 98%) of (R)-23a in an MV-4-11 xenograft model, while displaying improved tolerability compared with single agent combination. Moreover, in a syngeneic MC38 mouse colorectal tumor model, (R)-23a outperformed the combinatory treatment in reshaping the tumor immune microenvironment and inducing tumor regression. Collectively, the novel DNMT1/HDAC dual inhibitor (R)-23a effectively reverses the cancer-specific epigenetic abnormalities and holds great potential for further development into cancer therapeutic agents.

Clinical efficacy and immune response of BCL-2 inhibitors combined with hypomethylating agents in the treatment of acute myeloid leukemia

ObjectiveAcute myeloid leukemia (AML) is a malignant clonal proliferative disease with a high mortality rate. The combination therapy of BCL-2 inhibitor Venetoclax (VEN) and hypomethylating agents (HMAs) has significant anti-leukemia activity.MethodsWe analyzed the efficacy, safety and immune response characteristics of AML patients who were unfit for high-dose chemotherapy and accepted the medication of VEN + HMAs.ResultsAfter VEN + HMAs treatment, 31 newly diagnosed AML patients had the morphologic leukemia-free state rate (MLFS%) of 80.6% (25/31), complete response rate (CR%) of 54.8% (17/31), the minimal residual disease negative rate (MRD-%) of 51.6% (16/31), and the median progression-free survival (PFS) of 14 months. After treatment, the proportion of bone marrow primitive cells, the MRD level, white blood cell (WBC) count, fibrinogen (FIB) level and the proportion of B cells were significantly decreased. The red blood cell (RBC) count, hemoglobin (HGB) level, platelet count (PLT) count, activated partial thromboplastin time (APTT), the proportion of total T cells, CD8 + T cells and the IFN-γ level were significantly increased. After VEN + HMAs treatment, 12 relapsed AML patients had a MLFS% of 50% (6/12), CR% of 33.3% (4/12), MRD-% of 25% (3/12), and a median PFS of 7 months. After treatment, the proportion of bone marrow primitive cells and MRD level were slightly decreased, the proportions of CD8 + T cells and NK cells were significantly increased, the proportion of B cells and IL-10 level were significantly decreased. 12 AML patients who receive microtransplantation (MST) treatment using VEN + HMAs as a pretreatment regimen had a PFS of 20.5 months, which was much greater than VEN + HMAs group alone. Hematological recovery was better in the MST group with significantly increased RBC count, HGB level and PLT count. The most common adverse events were myelosuppression, agranulocytosis, infection and cardiovascular toxicity. No fatal adverse events were reported.ConclusionThe combination of BCL-2 inhibitors and HMAs had good efficacy and safety in AML patients who were unfit for high-dose chemotherapy, which may improve the immune microenvironment and enhance anti-leukemia immune response.

Abstract B062: Low dose dual epigenetic therapy utilizing hypomethylating agents and HDAC inhibitors prolong survival in an orthotopic PDAC model and alter the tumor microenvironment

Abstract Background: We have previously studied the effect of hypomethylating agent Decitabine (5- aza-dC; DAC) on pancreatic cancer using the KPC model (KrasG12D/+;Trp53R172H/+;Pdx1- Cre) and observed increased CD4+/CD8+ TILs, greater PD1 expression and slowed tumor growth with increased tumor necrosis. Subsequently we showed a significant survival benefit with DAC+αPD1 compared to either single agent. However, we identified a specific myeloid cell population initially identified by Chi3l3 expression that may be responsible for treatment resistance or escape. Based on prior observations of synergy specifically affecting tumor infiltrating myeloid and lymphoid cells, we focused on identifying a dual epigenetic strategy (a combination of DAC plus histone deacetylase inhibitors (HDACi)) to enhance immunological synergy and test their treatment efficacy with αPD1. Methods: We used a combination primary KPC-derived cell lines, bone marrow (BMDM) and peritoneum derived (PM) myeloid cells and T cells in co-culture systems to assess cytotoxic synergy (Bliss/Lowe consensus) and immune effects (cytokine release, myeloid cell polarization and T cell activation) to evaluate combinations of DAC+HDACi. The KPC orthotopic model relying on US monitoring of tumor size for standardized initiation of therapy was used for survival analysis and profiling in treatment combinations of DAC+HDACi+αPD1. Results: We showed that hypomethylation therapy exerts a primarily paracrine effect on myeloid cells and this polarization results in a decrease in DAC–induced T cell activation. We therefore selected HDAC inhibitors that in combination with DAC alter this paracrine effect. We selected specific HDAC inhibitors based on induction of class of HDAC expression following hypomethylation therapy, highest Bliss synergy scores at low doses and reversal of cytokine release, M2 polarization and T cell inactivation. Three HDAC inhibitors were chosen for in vivo testing, Domatinostat, Pracinostat and Entinostat. Using the treatment paradigm of ultra-low dose DAC+ HDACi (mainly to minimize toxicity) combined with αPD1 in the KPC orthotopic model we show that the triple combination (DAC + Entinostat + αPD1) is well-tolerated and results in a significant survival benefit compared to single and dual agent combinations. In addition, we also demonstrate a reduction in the Chi3l3 expressing myeloid cell population. Conclusions: Our results show that the combination of hypomethylating agent plus HDAC inhibitor has several beneficial effects on the tumor immune response in PDAC. HDAC inhibitors specifically reduce the suppressive myeloid cell population we previously identified after DAC therapy. The combination of dual low dose epigenetic therapy using a hypomethylating agent plus HDAC inhibitor followed by αPD1 results in significant survival benefit in the orthotopic KPC model. Citation Format: Stephen Muzyka, Arturo Orlacchio, Amanda Ackermann, Yasmine Chinda, Yoona Shim, Igor Dolgalev, Tamas Gonda. Low dose dual epigenetic therapy utilizing hypomethylating agents and HDAC inhibitors prolong survival in an orthotopic PDAC model and alter the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B062.