Combating breast cancer progression through combination therapy with hypomethylating agent and glucocorticoid

Breast cancer is the leading cause of cancer-related death in women. Among breast cancer types, triple-negative breast cancer (TNBC) accounts for 15% of all breast cancers with aggressive tumor behavior. By using bioinformatic approaches, we observed that the microRNA-708 promoter is highly methylated in breast carcinomas, and this methylation is linked to a poor prognosis. Moreover, microRNA-708 expression correlates with better clinical outcomes in TNBC patients. Combination treatment with the hypomethylating agent decitabine and synthetic glucocorticoid significantly increased the expression of microRNA-708, reactivated DNMT-suppressed pathways, and decreased the expression of multiple metastasis-promoting genes such as matrix metalloproteinases (MMPs) and IL-1β, leading to the suppression of breast cancer cell proliferation, migration, and invasion, as well as reduced tumor growth and distant metastasis in the TNBC xenograft mouse model. Overall, our study reveals a therapeutic opportunity in which a combined regimen of decitabine with glucocorticoid may have therapeutic potential in treating TNBC patients.

Cladribine- and decitabine-containing conditioning regimen has a low post-transplant relapse rate in patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome

To reduce the risk of relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT), there have been continuing efforts to optimize the conditioning regimens. Our study aimed to analyze the risk factors associated with the relapse of relapsed/refractory (R/R), high-risk acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) post-transplant and the efficacy of a new conditioning regimen involving decitabine and cladribine. Clinical data of 125 patients with R/R AML, high-risk AML and high-risk MDS who underwent allo-HSCT were collected. In addition, 35 patients with R/R AML, high-risk AML and high-risk MDS received treatment with a new conditioning regimen including decitabine and cladribine. Cox regression analysis was used to identify risk factors associated with OS, RFS and relapse. Among 125 patients who underwent allo-HSCT, CR before allo-HSCT and matched sibling donors were independent protective factors for OS. DNMT3A abnormality was an independent risk factor for both relapse and RFS. Among 35 patients who received a new conditioning regimen containing decitabine and cladribine, only six patients relapsed and 1-year cumulative incidence of relapse was 11.7%. Moreover, this new regimen showed efficient MRD clearance early after allo-HSCT. The combined decitabine- and cladribine-based conditioning regimen showed a low relapse rate and a high survival without an increased incidence of GVHD or adverse effects and thus has potential for use in allo-HSCT for R/R AML, high-risk AML and high-risk MDS.

5-Aza-2′-Deoxycytidine (5-Aza-dC, Decitabine) Inhibits Collagen Type I and III Expression in TGF-β1-Treated Equine Endometrial Fibroblasts

Endometrosis negatively affects endometrial function and fertility in mares, due to excessive deposition of type I (COL1) and type III (COL3) collagens. The pro-fibrotic transforming growth factor (TGF-β1) induces myofibroblast differentiation, characterized by α-smooth muscle actin (α-SMA) expression, and collagen synthesis. In humans, fibrosis has been linked to epigenetic mechanisms. To the best of our knowledge, this has not been described in mare endometrium. Therefore, this study aimed to investigate the in vitro epigenetic regulation in TGF-β1-treated mare endometrial fibroblasts and the use of 5-aza-2′-deoxycytidine (5-aza-dC), an epigenetic modifier, as a putative treatment option for endometrial fibrosis. Methods and Results: The in vitro effects of TGF-β1 and of 5-aza-dC on DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B), COL1A1, COL3A1, and α-SMA transcripts were analyzed in endometrial fibroblasts, and COL1 and COL3 secretion in a co-culture medium. TGF-β1 upregulated DNMT3A transcripts and collagen secretion. In TGF-β1-treated endometrial fibroblasts, DNA methylation inhibitor 5-aza-dC decreased collagen transcripts and secretion, but not α-SMA transcripts. Conclusion: These findings suggest a possible role of epigenetic mechanisms during equine endometrial fibrogenesis. The in vitro effect of 5-aza-dC on collagen reduction in TGF-β1-treated fibroblasts highlights this epigenetic involvement. This may pave the way to different therapeutic approaches for endometrosis.

Bioinformatics and System Biology Approach to Reveal the Interaction Network and the Therapeutic Implications for Non-Small Cell Lung Cancer Patients With COVID-19

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the leading cause of coronavirus disease-2019 (COVID-19), is an emerging global health crisis. Lung cancer patients are at a higher risk of COVID-19 infection. With the increasing number of non-small-cell lung cancer (NSCLC) patients with COVID-19, there is an urgent need of efficacious drugs for the treatment of COVID-19/NSCLC.

Methods: Based on a comprehensive bioinformatic and systemic biological analysis, this study investigated COVID-19/NSCLC interactional hub genes, detected common pathways and molecular biomarkers, and predicted potential agents for COVID-19 and NSCLC.

Results: A total of 122 COVID-19/NSCLC interactional genes and 21 interactional hub genes were identified. The enrichment analysis indicated that COVID-19 and NSCLC shared common signaling pathways, including cell cycle, viral carcinogenesis, and p53 signaling pathway. In total, 10 important transcription factors (TFs) and 44 microRNAs (miRNAs) participated in regulations of 21 interactional hub genes. In addition, 23 potential candidates were predicted for the treatment of COVID-19 and NSCLC.

Conclusion: This study increased our understanding of pathophysiology and screened potential drugs for COVID-19 and NSCLC.

Synergistic Therapeutic Effects of Low Dose Decitabine and NY-ESO-1 Specific TCR-T Cells for the Colorectal Cancer With Microsatellite Stability

Patients of colorectal cancer (CRC) with microsatellite stability (MSS) show poor clinical response and little beneficial result from the immune-checkpoint inhibitors, due to the ‘cold’ tumor microenvironment. Meanwhile, decitabine can drive the ‘cold’ microenvironment towards ‘hot’ in multiple ways, such as upregulating the tumor associated antigen (TAA) and human leukocyte antigen (HLA) molecular. NY-ESO-1, one of the most important TAAs, can be observably induced in tumors by low dose decitabine, and present itself as ideal targets for antigen specific T cell receptor engineered T (TCR-T) cells. We innovatively used a synergistic tactic, combining decitabine and NY-ESO-1 specific TCR-T cells, for fighting the MSS CRC. Firstly, we confirmed the lysing effect of the NY-ESO-1 TCR-T cells on the NY-ESO-1⁺ and HLA-A2⁺ cells in vitro and in vivo. In A375 tumor-bearing mice, the results showed that NY-ESO-1 TCR-T cell therapy could inhibit A375 tumor growth and prolonged the survival time. Furthermore, the synergistic effect of decitabine and NY-ESO-1 TCR-T cells was shown to induce an even higher percentage of tumor cells being lysed in vitro than other control groups, and more potent tumor inhibition and longer survival time were observed in vivo. The innovative synergistic therapeutic strategy of decitabine and TCR-T cells for the CRC with MSS may be also effective in the treatment of other epithelial malignancies. Decitabine may likewise be adopted in combination with other cellular immunotherapies.

Epi-immunotherapy for cancers: rationales of epi-drugs in combination with immunotherapy and advances in clinical trials

Over the last two decades, several epi-drugs, immune checkpoint inhibitors (ICIs) and adoptive cell therapies have received clinical approval for use in certain types of cancer. However, monotherapy with epi-drugs or ICIs has shown limited efficacy in most cancer patients. Epigenetic agents have been shown to regulate the crosstalk between the tumor and host immunity to alleviate immune evasion, suggesting that epi-drugs can potentially synergize with immunotherapy. In this review, we discuss recent insights into the rationales of incorporating epigenetic therapy into immunotherapy, called epi-immunotherapy, and focus on an update of current clinical trials in both hematological and solid malignancies. Furthermore, we outline the future challenges and strategies in the field of cancer epi-immunotherapy.

Low-Dose 5-Aza and DZnep Alleviate Acute Graft-Versus-Host Disease With Less Side Effects Through Altering T-Cell Differentiation

Objective

Previous studies showed that hypomethylating agents (HMAs) could alleviate acute graft-versus-host disease (aGvHD), but affect engraftment after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The combination of two different HMAs in lower doses might overcome this problem. This study aimed to evaluate the treatment effect of the combination of two HMAs—azacitidine (5-Aza) and histone H3K27 methyltransferase inhibitor 3-deazaneplanocin (DZNep)—for the prophylaxis of aGvHD after allo-HSCT and to explore the possible mechanisms.

Methods

We first optimized the concentrations of individual and combinational 5-Aza and DZNep treatments to ensure no obvious toxicities on activated T cells by evaluating T-cell proliferation, viability, and differentiation. A mouse model of aGvHD was then established to assess the prophylactic efficacy of 5-Aza, DZNep, and their combination on aGvHD. The immunomodulatory effect on T cells and the hematopoietic reconstruction were assessed. Additionally, RNA sequencing (RNA-seq) was performed to identify the underlying molecular mechanisms.

Results

Compared with single treatments, the in vitro application of 5-Aza with DZNep could more powerfully reduce the production of T helper type 1 (Th1)/T cytotoxic type 1 (Tc1) cells and increase the production of regulatory T cells (Tregs). In an allo-HSCT mouse model, in vivo administration of 5-Aza with DZNep could enhance the prophylactic effect for aGvHD compared with single agents. The mechanism study demonstrated that the combination of 5-Aza and DZNep in vivo had an enhanced effect to inhibit the production of Th1/Tc1, increase the proportions of Th2/Tc2, and induce the differentiation of Tregs as in vitro. RNA-seq analysis revealed the cytokine and chemokine pathways as one mechanism for the alleviation of aGvHD with the combination of 5-Aza and DZNep.

Conclusion

The combination of 5-Aza and DZNep could enhance the prophylactic effect for aGvHD by influencing donor T-cell differentiation through affecting cytokine and chemokine pathways. This study shed light on the effectively prophylactic measure for aGvHD using different epigenetic agent combinations.

Synergistic Inhibitory Effects of 5-Aza-2'-Deoxycytidine and Cisplatin on Urothelial Carcinoma Growth via Suppressing TGFBI-MAPK Signaling Pathways

This study is to reveal the gene transcriptional alteration, possible molecular mechanism, and pathways involved in the synergy of 5-aza-2'-deoxycytidine (DAC) and CDDP in UC. Two UC cell lines, 5637 and T24, were used in the study. A cDNA microarray was carried out to identify critical genes in the synergistic mechanism of both agents against UC cells. The results showed that several key regulatory genes, such as interleukin 24(IL24), fibroblast growth factor 1(FGF1), and transforming growth factor beta-induced (TGFBI), were identified and may play critical roles in the synergy of DAC and CDDP in UC. Pathway enrichment suggested that many carcinogenesis-related pathways, such as ECM-receptor interaction and MAPK signaling pathways, may participate in the synergy of both agents. Our results suggested that TGF-β1 stimulates the phosphorylation levels of ERK1/2 and p38 via increasing TGFBI expression, TGFBI-MAPK signaling pathway plays an important role in the synergy of DAC and CDDP against UC. Therefore, we revealed the synergistic mechanism of DAC and CDDP in UC, several key regulatory genes play critical roles in the synergy of combined treatment, and TGFBI-MAPK signaling pathway may be an important potential target of these two agents.

Microbiota and epigenetics: promising therapeutic approaches?

The direct/indirect responsibility of the gut microbiome in disease induction in and outside the digestive tract is well studied. These results are usually from the overpopulation of certain species on the cost of others, interaction with beneficial microflora, interference with normal epigenetic control mechanisms, or suppression of the immune system. Consequently, it is theoretically possible to cure such disorders by rebalancing the microbiome inside our bodies. This can be achieved by changing the lifestyle pattern and diet or by supplementation with beneficial bacteria or their metabolites. Various approaches have been explored to manipulate the normal microbial inhabitants, including nutraceutical, supplementations with prebiotics, probiotics, postbiotics, synbiotics, and antibiotics, or through microbiome transplantation (fecal, skin, or vaginal microbiome transplantation). In the present review, the interaction between the microbiome and epigenetics and their role in disease induction is discussed. Possible future therapeutic approaches via the reestablishment of equilibrium in our internal micro-ecosystem are also highlighted.

DNA methyltransferase inhibitors combination therapy for the treatment of solid tumor: mechanism and clinical application

DNA methylation, an epigenetic modification, regulates gene transcription and maintains genome stability. DNA methyltransferase (DNMT) inhibitors can activate silenced genes at low doses and cause cytotoxicity at high doses. The ability of DNMT inhibitors to reverse epimutations is the basis of their use in novel strategies for cancer therapy. In this review, we examined the literature on DNA methyltransferase inhibitors. We summarized the mechanisms underlying combination therapy using DNMT inhibitors and clinical trials based on combining hypomethylation agents with other chemotherapeutic drugs. We also discussed the efficacy of such compounds as antitumor agents, the need to optimize treatment schedules and the regimens for maximal biologic effectiveness. Notably, the combination of DNMT inhibitors and chemotherapy and/or immune checkpoint inhibitors may provide helpful insights into the development of efficient therapeutic approaches.

Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone

OBJECTIVES

This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism.

METHODS

Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR.

RESULTS

TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC₅₀ in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19).

CONCLUSIONS

The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.

Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone

OBJECTIVES

This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism.

METHODS

Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR.

RESULTS

TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC50 in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19).

CONCLUSIONS

The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.

Low-Dose Decitabine Augments the Activation and Anti-Tumor Immune Response of IFN-γ+ CD4+ T Cells Through Enhancing IκBα Degradation and NF-κB Activation

BACKGROUND

CD4+ T cells play multiple roles in controlling tumor growth and increasing IFN-γ+ T-helper 1 cell population could promote cell-mediated anti-tumor immune response. We have previously showed that low-dose DNA demethylating agent decitabine therapy promotes CD3+ T-cell proliferation and cytotoxicity; however, direct regulation of purified CD4+ T cells and the underlying mechanisms remain unclear.

METHODS

The effects of low-dose decitabine on sorted CD4+ T cells were detected both in vitro and in vivo. The activation, proliferation, intracellular cytokine production and cytolysis activity of CD4+ T cells were analyzed by FACS and DELFIA time-resolved fluorescence assays. In vivo ubiquitination assay was performed to assess protein degradation. Moreover, phosphor-p65 and IκBα levels were detected in sorted CD4+ T cells from solid tumor patients with decitabine-based therapy.

RESULTS

Low-dose decitabine treatment promoted the proliferation and activation of sorted CD4+ T cells, with increased frequency of IFN-γ+ Th1 subset and enhanced cytolytic activity in vitro and in vivo. NF-κB inhibitor, BAY 11-7082, suppressed decitabine-induced CD4+ T cell proliferation and IFN-γ production. In terms of mechanism, low-dose decitabine augmented the expression of E3 ligase β-TrCP, promoted the ubiquitination and degradation of IκBα and resulted in NF-κB activation. Notably, we observed that in vitro low-dose decitabine treatment induced NF-κB activation in CD4+ T cells from patients with a response to decitabine-primed chemotherapy rather than those without a response.

CONCLUSION

These data suggest that low-dose decitabine potentiates CD4+ T cell anti-tumor immunity through enhancing IκBα degradation and therefore NF-κB activation and IFN-γ production.

DNMT1 as a therapeutic target in pancreatic cancer: mechanisms and clinical implications

BACKGROUND

Pancreatic cancer or pancreatic ductal adenocarcinoma (PDAC) is one of the most devastating cancer types with a 5-year survival rate of only 9%. PDAC is one of the leading causes of cancer-related deaths in both genders. Epigenetic alterations may lead to the suppression of tumor suppressor genes, and DNA methylation is a predominant epigenetic modification. DNA methyltransferase 1 (DNMT1) is required for maintaining patterns of DNA methylation during cellular replication. Accumulating evidence has implicated the oncogenic roles of DNMT1 in various malignancies including PDACs.

CONCLUSIONS

Herein, the expression profiles, oncogenic roles, regulators and inhibitors of DNMT1 in PDACs are presented and discussed. DNMT1 is overexpressed in PDAC cases compared with non-cancerous pancreatic ducts, and its expression gradually increases from pre-neoplastic lesions to PDACs. DNMT1 plays oncogenic roles in suppressing PDAC cell differentiation and in promoting their proliferation, migration and invasion, as well as in induction of the self-renewal capacity of PDAC cancer stem cells. These effects are achieved via promoter hypermethylation of tumor suppressor genes, including cyclin-dependent kinase inhibitors (e.g., p14, p15, p16, p21 and p27), suppressors of epithelial-mesenchymal transition (e.g., E-cadherin) and tumor suppressor miRNAs (e.g., miR-148a, miR-152 and miR-17-92 cluster). Pre-clinical investigations have shown the potency of novel non-nucleoside DNMT1 inhibitors against PDAC cells. Finally, phase I/II clinical trials of DNMT1 inhibitors (azacitidine, decitabine and guadecitabine) in PDAC patients are currently underway, where these inhibitors have the potential to sensitize PDACs to chemotherapy and immune checkpoint blockade therapy.

DNA inhibitors for the treatment of brain tumors

Introduction: The worldwide incidence of central nervous system (CNS) primary tumors is increasing. Most of the chemotherapeutic agents used for treating these cancer types induce DNA damage, and their activity is affected by the functional status of repair systems involved in the detection or correction of DNA lesions. Unfortunately, treatment of malignant high-grade tumors is still an unmet medical need.Areas covered: We summarize the action mechanisms of the main DNA inhibitors used for the treatment of brain tumors. In addition, studies on new agents or drug combinations investigated for this indication are reviewed, focusing our attention on clinical trials that in the last 3 years have been completed, terminated or are still recruiting patients.Expert opinion: Much still needs to be done to render aggressive CNS tumors curable or at least to transform them from lethal to chronic diseases, as it is possible for other cancer types. Drugs with improved penetration in the CNS, toxicity profile, and activity against primary and recurrent tumors are eagerly needed. Targeted agents with innovative mechanisms of action and ability to harness the cells of the tumor microenvironment against cancer cells represent a promising approach for improving the clinical outcome of CNS tumors.

Decitabine-Containing Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Intermediate- and High-Risk Myelodysplastic Syndrome/Acute Myeloid Leukemia: Potential Decrease in the Incidence of Acute Graft versus Host Disease

Purpose

To evaluate the role of Decitabine in the allo-HSCT conditioning regimen for intermediate- and high-risk patients with MDS or AML.

Patients and methods

Retrospective analysis of data pertaining to 76 intermediate- and high-risk patients with MDS or AML who underwent allo-HSCT between December 2005 and June 2018 at the Peking University First Hospital. Forty patients received Decitabine-containing conditioning regimen before transplantation, while thirty-six patients received regimen without Decitabine.

Results

Over a median follow-up of 40 months (range, 1 to 155), the cumulative incidence of grade II to IV acute graft versus host disease was 12.4% [95% confidence interval (CI) 4.9–30.9%] in the Decitabine group and 41.5% (95% CI 28.1–61.2%) in the non-Decitabine group (P=0.005). On multivariate analysis, Decitabine-containing conditioning regimen was found to protect against grade II to IV aGVHD (HR=0.279, 95% CI 0.102–0.765, P=0.013). Incidence of respiratory infection in the Decitabine and non-Decitabine groups was 22.5% and 52.78%, respectively (P=0.012). No significant between-group difference was observed with respect to 3-year OS, DFS, or RR (P=0.980, 0.959, and 0.573, respectively), while the median relapse time was longer in the Decitabine group [7 months (range, 2–12) versus 3 months (range, 2–4), P=0.171]. Decitabine-containing conditioning showed a tendency for lower relapse rate among higher risk patients, as assessed by IPSS R; however, the between-group difference was not statistically significant (P=0.085).

Conclusion

Inclusion of Decitabine in the conditioning regimen for allo-HSCT in intermediate- and high-risk patients may lower the incidence of aGVHD and respiratory infections, and contribute to longer median relapse time.

Decitabine enhances tumor recognition by T cells through upregulating the MAGE-A3 expression in esophageal carcinoma

Cancer testis (CT) antigens are expressed in various types of tumors and represent the potential targets for T cell-based immunotherapy. Analysis of CT gene expression and DNA methylation have indicated that certain CT genes are epigenetically regulated and studies have confirmed that certain CT antigens are regulated by DNA methylation. In this study, we explored the epigenetic regulation of MAGE-A3 and improved the clinical outcome of MAGE-A3-specific T cell therapy in esophageal squamous cell carcinoma (ESCC). We used molecular profiling datasets in The Cancer Genome Atlas to analyze CT gene expression in ESCC and its regulation by DNA methylation. We performed quantitative reverse transcription PCR (qRT-PCR), immunohistochemistry and bisulfite sequencing in ESCC cell lines and ESCC tissues. Functional assays, such as flow cytometry, cytotoxicity assays and ELISA, were performed to determine the demethylation agent, decitabine (5-aza-2'-deoxycytidine, DAC)-treated cancer cell improved antigen specific T cells response. ESCC tumor cell-xenograft mouse model and enzyme-linked immunospot (ELISPOT) assays were used to determine the function of DAC treatment in enhancing anti-MAGE-3 T cell responses in ESCC. Furthermore, we performed qRT-PCR and flow cytometry in the peripheral blood mononuclear cells (PBMC) of myelodysplastic syndromes (MDS) patients. MAGE-A3, one of the CT antigens, expressed at various levels in ESCC and was interfered by DNA methylation. We observed an efficient increase in MAGE-A3 expression in tumor cells and tissues after the treatment of decitabine and the expression of MAGE-A3 was affected by DNA methylation. Functional assays showed enhanced secretion of IFN-γ and cytolysis of MAGE-A3 antigen-specific T cells by DAC-treated target cells. In the tumor cell-xenograft mouse model and ELISPOT assays, DAC increased the expression of MAGE-A3 and T cell mediated tumor clearance in ESCC as well. Notably, the proportions of MAGE-A3-responsive T cells were elevated in DAC-treated patients with MDS, indicating DAC dismissed the epigenetic inhibition of MAGE-A3. DAC would probably improve the clinical outcome of MAGE-A3-specific T cell therapy by augmenting the expression of target gene.

Differential Regulation of Methylation-Regulating Enzymes by Senescent Stromal Cells Drives Colorectal Cancer Cell Response to DNA-Demethylating Epi-Drugs

The advanced-stage colon cancer spreads from primary tumor site to distant organs where the colon-unassociated stromal population provides a favorable niche for the growth of tumor cells. The heterocellular interactions between colon cancer cells and colon-unassociated fibroblasts at distant metastatic sites are important, yet these cell-cell interactions for therapeutic strategies for metastatic colon cancer remain underestimated. Recent studies have shown the therapeutic potential of DNA-demethylating epi-drugs 5-azacytidine (AZA) and 5-aza-2'-deoxycytidine (DAC) for the treatment of solid tumors. While the effects of these epi-drugs alone or in combination with other anticancer therapies are well described, the influence of stromal cells and their secretome on cancer cell response to these agents remain elusive. In this study, we determined the effect of normal and senescent colon-unassociated fibroblasts and their conditioned medium on colorectal cancer (CRC) cell response to AZA and DAC using a cell-based DNA demethylation reporter system. Our data show that fibroblasts accelerate cell proliferation and differentially regulate the expression of DNA methylation-regulating enzymes, enhancing DAC-induced demethylation in CRC cells. In contrast, the conditioned medium from senescent fibroblasts that upregulated NF-κB activity altered deoxycytidine kinase levels in drug-untreated CRC cells and abrogated DAC effect on degradation of DNA methyltransferase 1. Similar to 2D cultures, senescent fibroblasts increased DNA demethylation of CRC cells in coculture spheroids, in addition to increasing the stemness of CRC cells. This study presents the first evidence of the effect of normal and senescent stromal cells and their conditioned medium on DNA demethylation by DAC. The data show an increased activity of DAC in high stromal cell cocultures and suggest the potential of the tumor-stroma ratio in predicting the outcome of DNA-demethylating epigenetic cancer therapy.

DNA demethylating agent decitabine broadens the peripheral T cell receptor repertoire

Purpose

Decitabine, a promising epi-immunotherapeutic agent has shown clinical responses in solid tumor patients, while the anti-tumor mechanisms were unclear. We aimed to investigate the immunomodulatory effect of decitabine in peripheral T cells.

Experimental design

We applied next-generation sequencing to investigate the complementarity-determining region 3 (CDR3) of the TCRβ gene, the diversity of which acts as the prerequisite for the host immune system to recognize the universal foreign antigens. We collected the peripheral blood mononuclear cells (PBMCs) from 4 patients, at baseline and after 2 cycles of low-dose decitabine therapy.

Results

An increase of the unique productive sequences of the CDR3 of TCRβ was observed in all of the 4 patients after decitabine treatment, which was characterized by a lower abundance of expanded clones and increased TCR diversity compared with before decitabine treatment. Further analysis showed a tendency for CD4 T cells with an increased CD4/CD8 ratio in response to decitabine therapy. In addition, the genome-wide expression alterations confirmed the effects of decitabine on immune reconstitution, and the increase of TCR excision circles (TRECs) was validated.

Conclusions

The low-dose DNMT inhibitor decitabine broadens the peripheral T cell repertoire, providing a novel role for the epigenetic modifying agent in anti-tumor immune enhancement.

Epigenetic actions of environmental factors and promising drugs for cancer therapy

Carcinogenesis is known to be primarily associated with gene mutations. Recently, increasing evidence has suggested that epigenetic events also serve crucial roles in tumor etiology. Environmental factors, including nutrition, toxicants and ethanol, are involved in carcinogenesis through inducing epigenetic modifications, such as DNA methylation, histone deacetylase and miRNA regulation. Studying epigenetic mechanisms has facilitated the development of early diagnostic strategies and potential therapeutic avenues. Modulation at the epigenetic level, including reversing epigenetic modifications using targeted drugs, has demonstrated promise in cancer therapy. Therefore, identifying novel epigenetic biomarkers and therapeutic targets has potential for the future of cancer therapy. The present review discusses the environmental factors involved in epigenetic modifications and potential drug candidates for cancer therapy.

Antitumor Effects of Epidrug/IFNα Combination Driven by Modulated Gene Signatures in Both Colorectal Cancer and Dendritic Cells

Colorectal cancer results from the progressive accumulation of genetic and epigenetic alterations. IFN signaling defects play an important role in the carcinogenesis process, in which the inability of IFN transcription regulatory factors (IRF) to access regulatory sequences in IFN-stimulated genes (ISG) in tumors and in immune cells may be pivotal. We reported that low-dose combination of two FDA-approved epidrugs, azacytidine (A) and romidepsin (R), with IFNα2 (ARI) hampers the aggressiveness of both colorectal cancer metastatic and stem cells in vivo and triggers immunogenic cell death signals that stimulate dendritic cell (DC) function. Here, we investigated the molecular signals induced by ARI treatment and found that this drug combination increased the accessibility to regulatory sequences of ISGs and IRFs that were epigenetically silenced in both colorectal cancer cells and DCs. Likewise, specific ARI-induced histone methylation and acetylation changes marked epigenetically affected ISG promoters in both metastatic cancer cells and DCs. Analysis by ChIP-seq confirmed such ARI-induced epigenetically regulated IFN signature. The activation of this signal endowed DCs with a marked migratory capability. Our results establish a direct correlation between reexpression of silenced ISGs by epigenetic control and ARI anticancer activity and provide new knowledge for the development of innovative combined therapeutic strategies for colorectal cancer. Cancer Immunol Res; 5(7); 604-16. ©2017 AACR.

Demethylating agent decitabine disrupts tumor-induced immune tolerance by depleting myeloid-derived suppressor cells

PURPOSE

The immunoregulatory effect of demethylating agent decitabine (DAC) has been recognized recently. However, little is known about its impact on immune tolerance. In this study, we aimed to determine the impact of DAC on the immune tolerance induced by tumor cells.

METHODS

The effects of DAC on immune cells in vivo were measured by flow cytometry. Myeloid-derived suppressor cells (MDSCs) were sorted using magnetic beads and cultured in vitro. The mixed lymphocyte reaction was used to determine the immunoregulatory effect of DAC in vitro. An adoptive transfusion mouse model was established to evaluate the effect in vivo.

RESULTS

We found that DAC treatment significantly depleted MDSCs in vivo by inducing MDSCs apoptosis. When given at a low dose, the immune effector cells were less affected by the treatment, except for MDSCs. The mixed lymphocyte reaction in vitro showed that T-cell responses were enhanced when MDSCs were depleted. Supplementation of MDSCs would attenuate this T-cell activation effect. Using an adoptive transfusion mouse model, we further demonstrated in vivo that DAC treatment could induce autologous anti-tumor immune response by depleting MDSCs.

CONCLUSIONS

This study is the first to illustrate DAC's immunoregulatory effect on immune tolerance. The disruption of immune tolerance is due to MDSCs depletion that induces an autologous immune response in vivo. By depleting MDSCs, DAC treatment removes one of the obstacles affecting anti-tumor immune activation and warrants further experimental and clinical studies to explore its potential utility in combination with various anti-tumor immunotherapies in the future.

Contribution of epigenetic mechanisms to variation in cancer risk among tissues

Recently, it was suggested that tissue variation in cancer risk originates from differences in the number of stem-cell divisions underlying each tissue, leading to different mutation loads. We show that this variation is also correlated with the degree of aberrant CpG island DNA methylation in normal cells. Methylation accumulates during aging in a subset of molecules, suggesting that the epigenetic landscape within a founder-cell population may contribute to tumor formation.

Combining Type I Interferons and 5-Aza-2'-Deoxycitidine to Improve Anti-Tumor Response against Melanoma

Resistance to IFN-I-induced antineoplastic effects has been reported in many tumors and arises, in part, from epigenetic silencing of IFN-stimulated genes by DNA methylation. We hypothesized that restoration of IFN-stimulated genes by co-administration of the demethylating drug 5-aza-2'-deoxycitidine (decitabine [DAC]) may enhance the susceptibility to IFN-I-mediated antitumoral effects in melanoma. We show that combined administration of IFN-I and DAC significantly inhibits the growth of murine and human melanoma cells, both in vitro and in vivo. Compared with controls, DAC/IFN-I-treated melanoma cells exhibited reduced cell growth, augmented apoptosis, and diminished migration. Moreover, IFN-I and DAC synergized to suppress the growth of three-dimensional human melanoma spheroids, altering tumor architecture. These direct antitumor effects correlated with induction of the IFN-stimulated gene Mx1. In vivo, DAC/IFN-I significantly reduced melanoma growth via stimulation of adaptive immunity, promoting tumor-infiltrating CD8⁺ T cells while inhibiting the homing of immunosuppressive CD11b⁺ myeloid cells and regulatory T cells. Accordingly, exposure of human melanoma cells to DAC/IFN-I induced the recruitment of immune cells toward the tumor in a Matrigel (Corning Life Sciences, Kennebunkport, ME)-based microfluidic device. Our findings underscore a beneficial effect of DAC plus IFN-I combined treatment against melanoma through both direct and immune-mediated anti-tumor effects.

Role of epigenetics in modulation of immune response at the junction of host-pathogen interaction and danger molecule signaling

Epigenetic mechanisms have rapidly and controversially emerged as silent modulators of host defenses that can lead to a more prominent immune response and shape the course of inflammation in the host. Thus, the epigenetics can both drive the production of specific inflammatory mediators and control the magnitude of the host response. The epigenetic actions that are predominantly shown to modulate the host defense against microbial pathogens are DNA methylation, histone modification and the activity of non-coding RNAs. There is also growing evidence that opportunistic chronic pathogens, such as Porphyromonas gingivalis, as a microbial host subversion strategy, can epigenetically interfere with the host DNA machinery for successful colonization. Similarly, the novel involvement of small molecule 'danger signals', which are released by stressed or infected cells, at the center of host-pathogen interplay and epigenetics is developing. In this review, we systematically examine the latest knowledge within the field of epigenetics in the context of host-derived danger molecule and purinergic signaling, with a particular focus on host microbial defenses and infection-driven chronic inflammation.

Quantitative proteomic analysis of histone modifications in decitabine sensitive and resistant leukemia cell lines

Background

The refractory nature of many cancers remains the main health challenge over the past century. The epigenetic drug, decitabine (DAC), represents one of the most promising therapeutic agents in cancers particularly in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, its ambiguous anti-tumor mechanism and the unpredictable drug-resistant nature in some population compromise its application in cancer therapy. In crosstalk with DNA methylation, histone post-translational modifications (PTMs) are the key players in modulating the downstream epigenetic status of tumor suppressor genes. This study targets the role of decitabine in epigenetic regulation in leukemia therapy and searches responsive predictors and therapeutic targets for pretreatment evaluation and drug development.

Results

A simple, fast, and robust proteomic strategy identified 15 novel PTMs and 60 PTM combinations in two leukemia cell lines (MDS-L and TF-1). Histone modification profiles have been generated and compared between DAC sensitive and resistant groups (n = 3) in response to DAC treatment. Among these histone PTMs, five of which were found differentially upon DAC treatment in drug sensitive and resistant cells: H3.3K36me3, H4K8acK12acK16ac in MDS-L cells; and H3.1K27me1, H3.1K36me1, H3.1K27me1K36me1 in TF-1 cells. They may serve as biomarkers in predicting leukemia and drug responsiveness. In addition, we also explored PTM differences in two cell lines which were developed from early and advanced stages of AML. Three PTMs (H3.1K27me3, H3.1K27me2K36me2 and H3.3K27me2K36me2) are highly abundant in TF-1 cells (advanced AML cell line), suggesting their relevance to leukemogenesis. Our method allowed deep analysis of histone proteins and elucidation of a large number of histone PTMs with high precision and sensitivity.

Conclusion

DAC-induced DNA hypomethylation has wide impact on chromatin modifications. This study represents first effort to investigate the undefined epigenetic mechanism of decitabine in leukemia therapy. The identification of 15 novel PTMs and the discovery of several marks have relevance to epigenetic directed therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-016-9115-z) contains supplementary material, which is available to authorized users.

Low-dose DNA-demethylating agent enhances the chemosensitivity of cancer cells by targeting cancer stem cells via the upregulation of microRNA-497

PURPOSE

The DNA-demethylating agent decitabine has shown clinical response for the treatment of hematological malignancies and solid tumors, while the mechanisms underlying its antitumor capacity are not fully understood.

METHODS

The sensitivities of cancer cells to different chemotherapeutic drugs, such as cisplatin, paclitaxel, and 5-FU, were detected. The tumor sphere formation assay was used to evaluate the effects of low-dose decitabine on cancer-initiating stem cells.

RESULTS

We observed that the chemotherapy sensitivity of various cancer cells was enhanced following non-toxic low-dose decitabine treatment. Moreover, low-dose decitabine treatment suppressed the self-renewal of cancer-initiating cells and inhibited the expression of pluripotency markers. Strikingly, low-dose decitabine was able to augment chemosensitivity in cancer stem cells, likely by the upregulation of miRNA-497, which was reported to be downregulated and to have promoted cell apoptosis in multiple cancers.

CONCLUSIONS

These results indicated that the DNA-demethylating agent could target cancer stem cells and reverse their chemotherapeutic resistance by regulating the endogenous expression of microRNAs.

Decitabine Enhances Lymphocyte Migration and Function and Synergizes with CTLA-4 Blockade in a Murine Ovarian Cancer Model

The lack of second-line treatment for relapsed ovarian cancer necessitates the development of improved combination therapies. Targeted therapy and immunotherapy each confer clinical benefit, albeit limited as monotherapies. Ovarian cancer is not particularly responsive to immune checkpoint blockade, so combination with a complementary therapy may be beneficial. Recent studies have revealed that a DNA methyl transferase inhibitor, azacytidine, alters expression of immunoregulatory genes in ovarian cancer. In this study, the antitumor effects of a related DNA methyl transferase inhibitor, decitabine (DAC), were demonstrated in a syngeneic murine ovarian cancer model. Low-dose DAC treatment increases the expression of chemokines that recruit NK cells and CD8(+) T cells, promotes their production of IFNγ and TNFα, and extends the survival of mice bearing subcutaneous or orthotopic tumors. While neither DAC nor immune checkpoint blockade confers durable responses as a monotherapy in this model, the efficacy of anti-CTLA-4 was potentiated by combination with DAC. This combination promotes differentiation of naïve T cells into effector T cells and prolongs cytotoxic lymphocyte responses as well as mouse survival. These results suggest that this combination therapy may be worthy of further consideration for improved treatment of drug-resistant ovarian cancer.