Downregulation of A20 increases the cytotoxicity of IFN-γ in hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a highly fatal disease mandating development of novel, effective therapeutic strategy. Interferon-gamma (IFN-γ) is a pleiotropic cytokine with immunomodulatory, antiviral, and antitumor effects. Although IFN-γ is a promising antitumor agent, its application is limited by resistance in tumor cells. A20 is a zinc-finger protein that was initially identified as a gene product induced by tumor necrosis factor α in human umbilical vein endothelial cells. In this study, we found that silencing of A20 combined with IFN-γ significantly represses cell viability, and induces apoptosis and cell-cycle arrest in HCC cells. By investigating mechanisms implicated in A20 and IFN-γ-mediated signaling pathways, we revealed that the phosphoinositide 3-kinase/Akt signaling pathway and antiapoptotic B-cell lymphoma 2 proteins were repressed. Moreover, we also found that phosphorylation of STAT1 and STAT3 was significantly enhanced after the downregulation of A20 in combination with treatment of IFN-γ. Inhibitor of STAT1 but not STAT3 could block the antitumor effect of IFN-γ. Therefore, targeting A20 enhances the cytotoxicity of IFN-γ against HCC cells and may present a promising therapeutic strategy for HCC.

Overexpression of the X-linked ribosomal protein S4 predicts poor prognosis in patients with intrahepatic cholangiocarcinoma.

X-linked ribosomal protein S4 (RPS4X) has previously been reported to be associated with cisplatin resistance and clinical outcome in bladder and ovarian cancer. However, the value of RPS4X as a diagnostic and prognostic marker in intrahepatic cholangiocarcinoma (ICC) has not yet been investigated. The present study evaluated the expression pattern, and diagnostic and prognostic value of RPS4X in patients with ICC. Retrospective analysis was performed for a total of 201 patients with intrahepatic cholangiocarcinoma, and 8 patients with inflammation of the bile duct. Immunohistochemistry was performed using tissue microarrays to characterize the expression profile of RPS4X. Receiver operating characteristic (ROC) curves, the Kaplan-Meier estimator and Cox regression analysis were applied to evaluate the potential diagnostic and prognostic value of RPS4X in ICC. RPS4X was significantly upregulated in ICC tissues compared with the inflamed bile duct tissues. When differentiating ICC from normal controls, ROC analysis of RPS4X gave an area under the curve value of 0.9030 (sensitivity, 82.59%; specificity, 100%). RPS4X expression was significantly positively correlated with serum alkaline phosphatase levels. Survival analysis demonstrated that RPS4X expression levels were an independent prognostic factor for overall survival. Therefore, RPS4X expression levels may serve as a novel diagnostic and prognostic marker in ICC.

miR-204 inhibits epithelial to mesenchymal transition by targeting slug in intrahepatic cholangiocarcinoma cells.

BACKGROUND/AIMS: MicroRNAs (miRNAs) play critical roles during carcinogenesis and cancer progression. Down-regulation of miR-204 has been frequently observed in various cancers. In this study, we investigated the roles and mechanisms of miR-204 in human intrahepatic cholangiocarcinoma (ICC). METHODS: The relative expression of miR-204 in ICC tissues and cell lines was monitored by qRT-PCR. Effects of miR-204 were studied in human ICC cell lines HuH28 and HuCCT1, and cells were analyzed for proliferation, migration and invasion. Expression levels of miR-204 target gene Slug and EMT markers (E-cadherin and vimentin) in ICC cell lines and tissues were measured by qRT-PCR, western blotting and immunofluorescence. RESULTS: miR-204 was frequently downregulated in human ICC, and the low-level expression of miR-204 was significantly associated with lymph node metastasis. Overexpression of miR-204 dramatically suppressed ICC cell migration and invasion, as well as the epithelial-mesenchymal transition process (EMT). Slug was identified as a direct target of miR-204, and its downregulation by miR-204 in HuH28 cells reversed EMT, as shown by the increased expression of the epithelial marker E-cadherin and decreased expression of the mesenchymal marker vimentin. CONCLUSION: These findings suggest that miR-204 plays negative roles in the invasive and/or metastatic potential of ICC, and that its suppressive effects are mediated by repressing Slug expression.