Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. Accumulating studies have demonstrated that aberrant expression of several lncRNAs was found to be involved in the hepatocarcinogenesis. In this study, a lncRNA Ftx was chosen to investigate its effects on HCC cells, and clarify the possible mechanism. We demonstrated that the lncRNA Ftx and Ftx-derived miR-545 were up-regulated in both HCC tissues and cells. MiR-545 was positively correlated with lncRNA Ftx expression. Notably, clinical association analysis revealed that the high expression of lncRNA Ftx and miR-545 was associated with poor prognostic features, and conferred a reduced 5-year overall survival (OS) and disease-free survival (DFS) of HCC patients. We found that miR-545 was a pivotal mediator in Ftx-induced promotion of HCC cell growth. Subsequently, we identified RIG-I as a direct target of miR-545. The expression of RIG-I was downregulated in HCC tissues and was inversely correlated with miR-545 expression. Our data revealed that ectopic expression of RIG-I abrogated the effects of lncRNA Ftx or miR-545 on HCC cells. LncRNA Ftx/miR-545-mediated downregulation of RIG-I led to increased Akt phosphorylation in vitro and in vivo. Inhibition of Akt phosphorylation abolished the effects of lncRNA Ftx/miR-545 on HCC cells. In conclusion, our study demonstrates that the novel pathway lncRNA Ftx/miR-545/RIG-I promotes HCC development by activating PI3K/Akt signaling, and it may serve as a novel prognostic biomarker and therapeutic target for HCC.

MicroRNA-212 (miR-212) has been reported to play oncogenic or tumor suppressive role in different human malignancies. Here, we demonstrated that the mean level of miR-212 in hepatocellular carcinoma (HCC) tissues was significantly lower than that in matched tumor-adjacent tissues. Similarly, the expression of miR-212 was obviously reduced in HCC cell lines as compared with a nontransformed hepatic cell line. Ectopic expression of miR-212 inhibited cell viability and proliferation, and induced apoptosis in HepG2 cells. In contrast, down-regulation of miR-212 increased cell viability and proliferation, and suppressed apoptosis in Bel-7402 cells. In vivo studies showed that miR-212 inhibited tumor growth of HCC via suppressing proliferation and inducing apoptosis. Furthermore, we confirmed that Forkhead box protein A1 (FOXA1) was a direct target of miR-212, and it abrogated the function of miR-212 in HCC. Finally, we disclosed that the aberrant expression of miR-212 and FOXA1 was evidently correlated with poor prognostic features of HCC. MiR-212, FOXA1 and their combination were valuable prognostic markers for predicting survival of HCC patients. In conclusion, miR-212 may serve as a prognostic indicator for HCC patients and exerts tumor suppressive role, at least in part, by inhibiting FOXA1.

No abstract

Despite advances in the roles of long non-coding RNA (lncRNA) tumor suppressor candidate 7 (TUSC7) in cancer biology, which has been identified as a tumor suppressor by regulating cell proliferation, apoptosis, migration, invasion, cell cycle, and tumor growth, the function of TUSC7 in hepatocellular carcinoma (HCC) remains unknown. In this study, we observed that the expression of TUSC7 was immensely decreased in HCC. Clinically, the lower expression of TUSC7 predicted poorer survival and may be an independent risk factor for HCC patients. Moreover, TUSC7 inhibited cell metastasis, invasion, and epithelial-to-mesenchymal transformation (EMT) through competitively binding miR-10a. Furthermore, we found that TUSC7 could decrease the expression of Eph tyrosine kinase receptor A4 (EphA4), a downstream target of miR-10a as well as an EMT suppressor, through TUSC7-miR-10a-EphA4 axis. Taken together, we demonstrate that TUSC7 suppresses EMT through the TUSC7-miR-10a-EphA4 axis, which may be a potential target for therapeutic intervention in HCC.

Tissue inhibitor of metalloproteinase 1 (TIMP-1) is an endogenous inhibitor for MMPs that regulates the remodeling and turnover of the ECM during normal development and pathological conditions. Intriguingly, recent studies have shown that TIMP-1 plays a dual role in cancer progression. In this study, we found that TIMP-1 expression in HCC tissues is associated with advanced TNM stage, intrahepatic metastasis, portal vein invasion, and vasculature invasion. Notably, TIMP-1 expression in HCC tissue is significantly related to worse overall survival for patients with HCC after liver resection. Ectopic TIMP1 expression promoted the growth of HCC xenografts in nude mice. Both co-culture with Huh7 cells with a high level of TIMP-1 and TIMP1 treatment resulted in up-regulation of hallmarks of carcinoma-associated fibroblasts (CAFs) and accelerated cell proliferation, migration and invasion in immortalized liver fibroblasts (LFs) isolated from human normal liver tissue. By co-culture with CAFs, SDF-1/CXCR4/PI3K/AKT signaling was activated and apoptosis was markedly repressed with an increased Bcl-2/BAX ratio in Huh7 cells. Taken together, our observations suggest that TIMP-1 induces the trans-differentiation of LFs into CAFs, suppresses apoptosis via SDF-1/CXCR4/PI3K/AKT signaling and then promotes HCC progression. This protein may be a potential prognostic biomarker and therapeutic target for HCC.