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Project description:The development of more effective targeted therapies for hepatocellular carcinoma (HCC) patients due to its aggressiveness is urgently needed. DNA methyltransferase inhibitors (DNMTis) represented the first clinical breakthrough to target aberrant cancer epigenomes. However, their clinical efficacies are still limited, in part due to an "epigenetic switch" in which a large group of genes that are demethylated by DNMTi treatment remain silenced by polycomb repressive complex 2 (PRC2) occupancy. EZH2 is the member of PRC2 that catalyzes the placement of H3K27me3 marks. EZH2 overexpression is correlated with poor HCC patient survival. We tested the combination of a DNMTi (5-aza-2'-deoxycytidine, DAC) and the EZH2 inhibitor (EZH2i) GSK126 in human HCC cell lines on drug sensitivity, DNA methylation, nucleosome accessibility, and gene expression profiles. Compared with single agent treatments, all HCC cell lines studied showed increased sensitivity after receiving both drugs concomitant with prolonged anti-proliferative changes and sustained reactivation of nascently-silenced genes. The increased number of up-regulated genes after combination treatment correlated with prolonged anti-proliferation effects and increased nucleosome accessibility. Combination treatments also activate demethylated promoters that are repressed by PRC2 occupancy. Furthermore, 13-31% of genes down-regulated by DNA methylation in primary HCC tumors were reactivated through this combination treatment scheme in vitro. Finally, the combination treatment also exacerbates anti-tumor immune responses, while most of these genes were downregulated in over 50% of primary HCC tumors. We have linked the anti-tumor effects of DAC and GSK126 combination treatments to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets and provided a rationale for treatment efficacy for HCC patients.
| S-EPMC9563073 | biostudies-literature
Project description:Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with cases increasing dramatically in the USA. Developing more effective targeted therapies for HCC is an urgent need. The FDA-approved DNA methyltransferase inhibitors (DNMTis) 5-azacytidine (5-aza-CR, Vidaza) and 5-aza-2’-deoxycytidine (5-aza-CdR, Decitabine) represented the first clinical breakthrough to target aberrant cancer epigenomes. However, the clinical efficacies of DNMTis are still limited, in part due to an “epigenetic switch” mechanism, in which a large group of genes demethylated by DNMTi treatment remain silenced by Polycomb Repressive Complex 2 (PRC2) occupancy. Overexpression of PRC2 subunits, especially EZH2, is correlated with poor patient survivor in HCC. In this study, we tested the combination of 5-Aza-CdR and the EZH2 inhibitor (EZH2i) GSK-126 in human HCC cell lines (SNU398, HepG2, and SNU475) on DNA methylation, nucleosome accessibility, and gene expression profiles. Compared with single agent treatments, all cell lines showed increased sensitivity after receiving both drugs concomitant with prolonged anti-proliferative changes and sustained reactivation of nascently silenced genes. The increased number of up-regulated genes, including tumor suppressors, were correlated with prolonged anti-proliferation effects and nucleosome accessibility but negatively correlated with gene promoter DNA methylation. Detailed epigenome analyses reveal a mechanistic rationale in which the combination treatment of 5-aza-CdR with an EZH2 inhibitor (EZH2i) activates demethylated promoters that are repressed by PRC2 occupancy. Furthermore, about 13.6% to 31% of genes down-regulated by DNA methylation in primary HCC tumors can be reactivated through this combination treatment scheme in vitro. Finally, combination treatment also exacerbates viral mimicry activation as well as leukocyte, lymphocyte and T cell mediated immunity, while most those genes or pathways were downregulated in over 50% of primary HCC tumors in TCGA dataset. Conclusion: we have linked the anti-tumor effects of DNMTi and EZH2i combination treatments to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets and provided a rationale for combination treatment efficacy in HCC patients.
2022-10-19 | GSE202559 | GEO
Project description:Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with cases increasing dramatically in the USA. Developing more effective targeted therapies for HCC is an urgent need. The FDA-approved DNA methyltransferase inhibitors (DNMTis) 5-azacytidine (5-aza-CR, Vidaza) and 5-aza-2’-deoxycytidine (5-aza-CdR, Decitabine) represented the first clinical breakthrough to target aberrant cancer epigenomes. However, the clinical efficacies of DNMTis are still limited, in part due to an “epigenetic switch” mechanism, in which a large group of genes demethylated by DNMTi treatment remain silenced by Polycomb Repressive Complex 2 (PRC2) occupancy. Overexpression of PRC2 subunits, especially EZH2, is correlated with poor patient survivor in HCC. In this study, we tested the combination of 5-Aza-CdR and the EZH2 inhibitor (EZH2i) GSK-126 in human HCC cell lines (SNU398, HepG2, and SNU475) on DNA methylation, nucleosome accessibility, and gene expression profiles. Compared with single agent treatments, all cell lines showed increased sensitivity after receiving both drugs concomitant with prolonged anti-proliferative changes and sustained reactivation of nascently silenced genes. The increased number of up-regulated genes, including tumor suppressors, were correlated with prolonged anti-proliferation effects and nucleosome accessibility but negatively correlated with gene promoter DNA methylation. Detailed epigenome analyses reveal a mechanistic rationale in which the combination treatment of 5-aza-CdR with an EZH2 inhibitor (EZH2i) activates demethylated promoters that are repressed by PRC2 occupancy. Furthermore, about 13.6% to 31% of genes down-regulated by DNA methylation in primary HCC tumors can be reactivated through this combination treatment scheme in vitro. Finally, combination treatment also exacerbates viral mimicry activation as well as leukocyte, lymphocyte and T cell mediated immunity, while most those genes or pathways were downregulated in over 50% of primary HCC tumors in TCGA dataset. Conclusion: we have linked the anti-tumor effects of DNMTi and EZH2i combination treatments to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets and provided a rationale for combination treatment efficacy in HCC patients.
2022-10-19 | GSE202560 | GEO
Project description:DNMT and EZH2 inhibitors synergize for gene activation in hepatocellular carcinoma cells.
| PRJNA836561 | ENA
Project description:DNMT and EZH2 inhibitors synergize for gene activation in hepatocellular carcinoma cells [methylation array]
| PRJNA836566 | ENA
Project description:DNMT and EZH2 inhibitors synergize for gene activation in hepatocellular carcinoma cells [RNA-seq]
| PRJNA836565 | ENA
Project description:Hepatocellular carcinoma (HCC) affects more than half a million people worldwide and is the third most common cause of cancer deaths. Because mammalian target of rapamycin (mTOR) signaling is up-regulated in 50% of HCCs, we compared the effects of the U.S. Food and Drug Administration-approved mTOR-allosteric inhibitor, RAD001, with a new-generation phosphatidylinositol 3-kinase/mTOR adenosine triphosphate-site competitive inhibitor, BEZ235. Unexpectedly, the two drugs acted synergistically in inhibiting the proliferation of cultured HCC cells. The synergistic effect closely paralleled eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) dephosphorylation, which is implicated in the suppression of tumor cell proliferation. In a mouse model approximating human HCC, the drugs in combination, but not singly, induced a marked regression in tumor burden. However, in the tumor, BEZ235 alone was as effective as the combination in inhibiting 4E-BP1 phosphorylation, which suggests that additional target(s) may also be involved. Microarray analyses revealed a large number of genes that reverted to normal liver tissue expression in mice treated with both drugs, but not either drug alone. These analyses also revealed the down-regulation of autophagy genes in tumors compared to normal liver. Moreover, in HCC patients, altered expression of autophagy genes was associated with poor prognosis. Consistent with these findings, the drug combination had a profound effect on UNC51-like kinase 1 (ULK1) dephosphorylation and autophagy in culture, independent of 4E-BP1, and in parallel induced tumor mitophagy, a tumor suppressor process in liver. These observations have led to an investigator-initiated phase 1B-2 dose escalation trial with RAD001 combined with BEZ235 in patients with HCC and other advanced solid tumors.
| S-EPMC3703151 | biostudies-literature
Project description:The CXC chemokine receptor 4 (CXCR4) exerts a variety of functions at different steps of hepatocellular carcinoma (HCC) progression. The molecular mechanisms and therapeutic value of CXCR4 in the development of HCC remain undefined. Here we show that aberrant CXCR4 overexpression is associated with poor prognosis and aggressive characteristics of HCC. Suppression of CXCR4 activity via CXCR4 knockdown, AMD3100 or neutralizing antibody administration inhibits hepatoma cell tumorigenesis in vitro and in vivo. CXCR4 overexpression displays the opposite effects. Using Mir library screening we identify miR-622 as a regulator of CXCR4. Further studies show that miR-622 directly target the 3' untranslated region of CXCR4 and is transcriptionally repressed by EZH2-induced H3K27 trimethylation and promoter methylation. EZH2/miR-622 promotes tumorigenesis through CXCR4. EZH2-mediated loss of miR-622 is found to correlate with CXCR4 overexpression and unfavourable prognosis in HCC patients. This study establishes EZH2/miR-622/CXCR4 as a potential adverse prognostic factor and therapeutic target for HCC patients.
| S-EPMC4598861 | biostudies-literature
Project description:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare but extremely lethal malignancy that mainly impacts young women. SCCOHT is characterized by a diploid genome with loss of SMARCA4 and lack of SMARCA2 expression, two mutually exclusive ATPases of the SWI/SNF chromatin-remodeling complex. We and others have identified the histone methyltransferase EZH2 as a promising therapeutic target for SCCOHT, suggesting that SCCOHT cells depend on the alternation of epigenetic pathways for survival. In this study, we found that SCCOHT cells were more sensitive to pan-HDAC inhibitors compared with other ovarian cancer lines or immortalized cell lines tested. Pan-HDAC inhibitors, such as quisinostat, reversed the expression of a group of proteins that were deregulated in SCCOHT cells due to SMARCA4 loss, leading to growth arrest, apoptosis, and differentiation in vitro and suppressed tumor growth of xenografted tumors of SCCOHT cells. Moreover, combined treatment of HDAC inhibitors and EZH2 inhibitors at sublethal doses synergistically induced histone H3K27 acetylation and target gene expression, leading to rapid induction of apoptosis and growth suppression of SCCOHT cells and xenografted tumors. Therefore, our preclinical study highlighted the therapeutic potential of combined treatment of HDAC inhibitors with EZH2 catalytic inhibitors to treat SCCOHT.
| S-EPMC6279577 | biostudies-literature
Project description:The urgent unmet need for hepatocellular carcinoma (HCC) therapies is addressed here by characterising a novel mouse model of HCC in the context of ongoing liver damage and overnutrition. Male C57Bl/6J mice were treated with diethylnitrosamine (DEN) and thioacetamide (TAA), and some were provided with an atherogenic high fat diet (HFD). Inflammation, steatosis, fibrosis, 87 genes, liver lesions and intratumoural leukocyte subsets were quantified up to 24 weeks of age. Adding HFD to DEN/TAA increased fibrosis, steatosis and inflammation, and the incidence of both HCC and non-HCC dysplastic lesions. All lesions contained α-SMA positive fibroblasts. Macrophage marker F4/80 was not significantly different between treatment groups, but the macrophage-associated genes Arg-1 and Cd47 were differentially expressed. Fibrosis, cancer and cell death associated genes were upregulated in DEN/TAA/HFD livers. Fewer Kupffer cells and plasmacytoid dendritic cells were in tumours compared to control liver. In conclusion, combining a hepatotoxin with an atherogenic diet produced more intrahepatic tumours, dysplastic lesions and fibrosis compared to hepatotoxin alone. This new HCC model provides a relatively rapid means of examining primary HCC and potential therapies in the context of multiple hepatotoxins including those derived from overnutrition.
| S-EPMC6035229 | biostudies-literature