MicroRNA-199b-5p attenuates TGF-ß1-induced epithelial-mesenchymal transition in hepatocellular carcinoma.

BACKGROUND: Accumulating evidence indicates that N-cadherin is a cell adhesion molecule that has critical roles in tumour progression. However, the role of N-cadherin in hepatocellular carcinoma (HCC) remains controversial. METHODS: This study aims to investigate the expression status of N-cadherin and its molecular mechanisms in HCC. RESULTS: The expression of N-cadherin was markedly overexpressed in HCC tissues and cell lines. We identified that miR-199b-5p binds to the 3'-UTR of N-cadherin mRNA, thus decreasing N-cadherin expression in HCC cells. We also found the downregulation of miR-199b-5p in HCC specimens, which was inversely correlated with N-cadherin upregulation, predicted poor clinical outcomes in HCC patients. Next, we determined that miR-199b-5p overexpression promoted cell aggregation, suppressed cell migration and invasion in HCC cells, and inhibited xenografts tumour metastasis in nude mice. Moreover, we demonstrated that miR-199b-5p attenuated TGF-ß1 induced epithelial-mesenchymal transition (EMT) -associated traits, while its effects could be partially reversed by N-cadherin restoration. Finally, we examined that N-cadherin downregulation or miR-199b-5p overexpression suppressed TGF-ß1-induced Akt phosphorylation, and inhibition of PI3K/Akt pathway blocked TGF-ß1-induced N-cadherin overexpression in HCC cells. CONCLUSIONS: Our data demonstrate that N-Cadherin was markedly overexpressed and miR-199b-5p was significantly downregulated in HCC. MiR-199b-5p exerts inhibitory effects on EMT, and directly targets N-cadherin in HCC, supporting the potential utility of miR-199b-5p as a promising strategy to treat HCC. Also, a positive regulatory loop exists between N-cadherin and Akt signalling represents a novel mechanism of TGF-ß1-mediated EMT in HCC cells.

Hepatitis B virus X protein promotes CREB-mediated activation of miR-3188 and Notch signaling in hepatocellular carcinoma.

Familiar clustering of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) has been frequently reported. However, limited information is available about the underlying molecular mechanisms in HBV-related HCC patients with family history of HCC. In our previous study, Agilent miRNA Base 16.0 microarray showed miRNA profiles of the plasma of HBV-related HCC patients who had a family history of HCC. This study aims to explore the expression, function, and mechanisms of miR-3188 in HCC that might provide novel insights into the role of family history on the risk of HCC. The expression levels of miR-3188 were markedly overexpressed in HCC tissues, HBV transgenic mice, and HepG2.215 cells. We knocked out miR-3188 in HCC cell lines using the CRISPR/Cas9 system, and demonstrated that miR-3188 knockout (KO) suppressed cell growth, migration, and invasion, and inhibited xenografts tumor growth in nude mice. Next, we determined that miR-3188 KO exerts antitumor functions by directly repressing ZHX2. It has been reported that HBV X protein (HBx) plays a critical role in HBV-related HCC, promoting CREB-mediated activation of miR-3188 and activation of Notch signaling through repressing ZHX2. Finally, we verified that ZHX2 functions as a transcriptional repressor to Notch1 via interaction with NF-YA. Our data demonstrate that the HBx-miR-3188-ZHX2-Notch1 signaling pathway plays an important role in the pathogenesis and progression of HBV-related HCC with family history of HCC. These findings have important implications for identifying new therapeutic targets in HBV-related HCC.

c-Jun N-terminal kinase inhibitor favors transforming growth factor-ß to antagonize hepatitis B virus X protein-induced cell growth promotion in hepatocellular carcinoma.

Transforming growth factor (TGF)-ß induces cell growth arrest in well-differentiated hepatocellular carcinoma (HCC) while hepatitis B virus X protein (HBx) minimizes the tumor suppression of TGF-ß signaling in early chronic hepatitis B. However, how to reverse the oncogenic effect of HBx and sustain the tumor-suppressive action of TGF-ß has yet to be investigated. The present study examined the effect of TGF-ß and a c-Jun N-terminal kinase (JNK) inhibitor on cell growth in HCC cells with forced expression of HBx. It was found that HBx promoted cell growth via activation of the JNK/pSMAD3L pathway and inhibition of the transforming growth factor-beta type I receptor (TßRI)/pSMAD3C pathway. pSMAD3L/SMAD4 and pSMAD3C/SMAD4 complexes antagonized each other to regulate c-Myc expression. In the absence of HBx, TGF-ß induced cell growth arrest through activation of the TßRI/pSMAD3C pathway in well-differentiated HCC cells. In the presence of HBx, TGF-ß had no effect on cell growth. JNK inhibitor SP600125 significantly reversed the oncogenic action of HBx and favored TGF-ß to regain the ability to inhibit the cell growth in HBx-expressing well-differentiated HCC cells. In conclusion, targeting JNK signaling favors TGF-ß to block HBx-induced cell growth promotion in well-differentiated HCC cells. As an adjunct to anti-viral therapy, the combination of TGF-ß and inhibition of JNK signaling is a potential therapy for HBV-infected HCC.

Minocycline and cisplatin exert synergistic growth suppression on hepatocellular carcinoma by inducing S phase arrest and apoptosis.

Minocycline, a semisynthetic tetracycline, is a highly lipophilic molecule capable of infiltrating tissues and blood. Previous studies have revealed the functions and mechanisms of minocycline in anti-inflammation, protection of the nervous system and certain tumors. The role of minocycline has never been investigated in hepatocellular carcinoma (HCC). The functions of minocycline on HCC cells were investigated using immunohistochemical staining and western blotting. Minocycline was applied to L02, HepG2 and Huh7 cells, and the growth characteristics were studied. Cisplatin was administered in combination with minocycline in this study. Cell cycle and apoptosis analyses were employed to investigate the mechanisms underlying the growth regulation associated with minocycline and(or) cisplatin. Minocycline caused S phase cell cycle arrest and an increase in the apoptotic rate associated with upregulation of p27, cleaved-caspase8, cleaved-caspase3 and cleaved-PRAP-1. Low dose of cisplatin promoted cell cycle arrest and apoptosis, whereas minocycline was mainly associated with upregulation of cleaved-PARP-1. The combination of cisplatin and minocycline increased the rate and extent of cell cycle arrest and increased the apoptosis rate caused by minocycline. A novel mechanism was revealed. Minocycline functions as an antitumor drug in HCC by regulating p27, caspase-3 and PARP-1. Cisplatin enhanced minocycline's effect on PARP-1.

Down-regulated KLF17 expression is associated with tumor invasion and poor prognosis in hepatocellular carcinoma.

Although the role of Krüppel-like factor 17 (KLF17) in regulating epithelial-mesenchymal transition (EMT) has been explored in breast cancer, its influence on primary hepatocellular carcinoma (HCC) remains unclear. This study aims to investigate the expression status of KLF17 in hepatocellular carcinoma (HCC) and the correlation between KLF17 expression and metastatic potential of HCC. KLF17 expression in HCC and adjacent liver tissues was studied by real-time PCR and Western blot, and the relationship between KLF17 expression and the clinicopathological features of HCC was evaluated in 60 patients. By using RNA interference technique, the correlation of KLF17 expression and metastatic potential was investigated by down-regulating KLF17 expression in HepG2 cells, and the effects of KLF17 down-regulation on cell migration, and invasion were then analyzed. Furthermore, the correlation between KLF17 expression and the surgical outcomes of a cohort of HCC patients was analyzed. Reduced expression of KLF17 is associated with a short survival time in clinical patients (P = 0.034). Low KLF17 expression is related to tumor T stage (P = 0.045), tumor size (P = 0.027), lymph node stage (P = 0.030), M stage (P = 0.048), and portal vein tumor thrombosis significantly in HCC. Reduced expression of KLF17 promoted motility and invasion ability of HepG2 cells and changed the expression of E-cadherin, ZO-1, Snai1, and vimentin (genes are associated with EMT). Overall, these findings suggest a repressing role of KLF17 in tumor invasion and a new prognostic indicator in directing therapy. It deserves further exploration.