c‑Jun suppresses the expression of WNT inhibitory factor 1 through transcriptional regulation and interaction with DNA methyltransferase 1 in gallbladder cancer

Computer analysis of regulation of hepatocarcinoma marker genes hypermethylated by HCV proteins

Hepatitis C virus (HCV) is a risk factor that leads to hepatocellular carcinoma (HCC) development. Epigenetic changes are known to play an important role in the molecular genetic mechanisms of virus-induced oncogenesis. Aberrant DNA methylation is a mediator of epigenetic changes that are closely associated with the HCC pathogenesis and considered a biomarker for its early diagnosis. The ANDSystem software package was used to reconstruct and evaluate the statistical significance of the pathways HCV could potentially use to regulate 32 hypermethylated genes in HCC, including both oncosuppressor and protumorigenic ones identified by genome-wide analysis of DNA methylation. The reconstructed pathways included those affecting protein-protein interactions (PPI), gene expression, protein activity, stability, and transport regulations, the expression regulation pathways being statistically significant. It has been shown that 8 out of 10 HCV proteins were involved in these pathways, the HCV NS3 protein being implicated in the largest number of regulatory pathways. NS3 was associated with the regulation of 5 tumor-suppressor genes, which may be the evidence of its central role in HCC pathogenesis. Analysis of the reconstructed pathways has demonstrated that following the transcription factor inhibition caused by binding to viral proteins, the expression of a number of oncosuppressors (WT1, MGMT, SOCS1, P53) was suppressed, while the expression of others (RASF1, RUNX3, WIF1, DAPK1) was activated. Thus, the performed gene-network reconstruction has shown that HCV proteins can influence not only the methylation status of oncosuppressor genes, but also their transcriptional regulation. The results obtained can be used in the search for pharmacological targets to develop new drugs against HCV-induced HCC.

The role of N-cadherin/c-Jun/NDRG1 axis in the progression of prostate cancer

The dysregulation of androgen receptor (AR) signaling is a critical event in the progression of prostate cancer (PCa) and hormone therapy consisting of androgen deprivation (ADT) or AR inhibition is therefore used to treat advanced cases. It is known that N-cadherin becomes upregulated following ADT and can directly induce PCa transformation to the castration-resistant stage (CRPC). However, the relationship between AR and N-cadherin is unclear and may promote better understanding of CRPC pathogenesis and progression. Here, we demonstrate a new axis of N-cadherin/c-Jun/N-myc downstream regulated gene 1 (NDRG1) that N-cadherin promotes c-Jun expression and suppresses NDRG1 to promote invasion and migration of PCa cells through epithelial to mesenchymal transition (EMT). Targeting N-cadherin in combination with enzalutamide (ENZ) treatment synergistically suppressed PC3 cell proliferation in vivo and in vitro. Further studies showed that compared to lower Gleason score (GS) (GS < 7) cases, high GS (GS > 7) cases exhibited elevated N-cadherin expression and reduced NDRG1 expression, corroborating our in vitro observations. We further demonstrate that c-Jun, AR, and DNA methyltransferase-1 (DNMT1) form a complex in the 12-O-tetradecanoyl phorbol-13-acetate (TPA) response elements (TREs) region of the NDRG1 promoter, which suppresses NDRG1 transcription through DNA hypermethylation. In conclusion, we demonstrate an underlying mechanism for how N-cadherin collaborates with AR and NDRG1 to promote CRPC progression. Controlling N-cadherin/c-Jun/NDRG1 axis may help to overcome resistance to commonly used hormone therapy to improve long-term patient outcomes.

Enhancer of Zeste Homolog 2 (EZH2) in Malignant Progression of Gallbladder Carcinoma

PURPOSE

Data related to the role of epigenetic modifications in gallbladder carcinoma (GBC) is limited. We intended to assess the role of crucial epigenetic modifiers pertaining to histone modification and DNA-methylation system in gallbladder carcinogenesis.

METHODS

The expression of EZH2, H3K27me3, and DNA methyltransferases (DNMTs) was analyzed by immunohistochemistry in cases of GBC (n = 39), gallbladder dysplasia (GBD, n = 12), and benign mucosa (BM, n = 16). A semi-quantitative scoring system was used for assessing the immunohistochemical expression.

RESULTS

The expression of EZH2 was significantly higher in cases of GBC than GBD (p value 0.001). The cases of BM were negative. Its expression was also higher in poorly differentiated tumors and positively correlated with the proliferative activity (MIB-1 labeling index) (p value 0.03 and 0.01, respectively). There was no significant difference in the expression levels of H3K27me3, DNMT-1, and DNMT-3B among GBC, GBD, and BM cases. Although GBC cases with strong EZH2 expression showed a shorter overall survival, the difference was not statistically significant.

CONCLUSION

This study highlights the crucial role of the key epigenetic regulators EZH2 in the pathobiology and evolution of gallbladder carcinogenesis. Given the reversibility of epigenetic alterations, EZH2 may be a novel therapeutic target for gallbladder carcinogenesis.