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Background: Cholangiocarcinoma (CCA) is a rare, aggressive and highly lethal tumor. The disease is very difficult to diagnose and multi-modality treatments are ineffective. To improve our understanding of the biological characteristics of CCA, and facilitate the identification of valid treatments, an in-depth characterization of two novel Chinese patient-derived primary CCA cell lines was performed., Methods: Two CCA cell lines were developed and labelled ZJU-0826 and -1125. The two cell lines were characterized with respect to phenotypic, molecular, biomarker, functional and histological properties., Results: Two novel cell lines were cultured for 2 years, and maintained for more than 100 passages. They retained their typical biliary epithelial morphology and ultrastructure. The population doubling times of ZJU-0826, and -1125 were 63.84 h and 44.73 h, respectively. The cells exhibited near-triploid karyotypes with complex structural aberrations. ZJU-1125 cells had mutations in TP53 exons. Short tandem repeats genotyping confirmed the human origin and difference between lines. An immunophenotype analysis showed that ZJU-0826 is positive for CD44, CD29, Pdx1, CD236, FoxA1, FoxA2, and Nanog, and ZJU-1125 positive for CD44, CD29, CD133, Pdx1, FoxA1, FoxA2, and Nanog. ZJU-1125 had greater invasion ability in vitro and tumorigenicity than those of ZJU-0826., Conclusions: Our results confirm the validity of the ZJU-0826 and -1125 as representative models for the elucidation of the molecular pathogenesis of perihilar CCA, and intrahepatic CCA in both in vitro and in vivo studies, respectively.

Down-regulation of the microRNA let-7c plays an important role in the pathogenesis of human hepatocellular carcinoma (HCC). The aim of the present study was to determine whether the cell cycle regulator CDC25A is involved in the antitumor effect of let-7c in HCC. The expression levels of let-7c in HCC cell lines were examined by quantitative real-time PCR, and a let-7c agomir was transfected into HCC cells to overexpress let-7c. The effects of let-7c on HCC proliferation, apoptosis and cell cycle were analyzed. The in vivo tumor-inhibitory efficacy of let-7c was evaluated in a xenograft mouse model of HCC. Luciferase reporter assays and western blotting were conducted to identify the targets of let-7c and to determine the effects of let-7c on CDC25A, CyclinD1, CDK6, pRb and E2F2 expression. The results showed that the expression levels of let-7c were significantly decreased in HCC cell lines. Overexpression of let-7c repressed cell growth, induced cell apoptosis, led to G1 cell cycle arrest in vitro, and suppressed tumor growth in a HepG2 xenograft model in vivo. The luciferase reporter assay showed that CDC25A was a direct target of let-7c, and that let-7c inhibited the expression of CDC25A protein by directly targeting its 3ʹ UTR. Restoration of CDC25A induced a let-7c-mediated G1-to-S phase transition. Western blot analysis demonstrated that overexpression of let-7c decreased CyclinD1, CDK6, pRb and E2F2 protein levels. In conclusion, this study indicates that let-7c suppresses HCC progression, possibly by directly targeting the cell cycle regulator CDC25A and indirectly affecting its downstream target molecules. Let-7c may therefore be an effective therapeutic target for HCC. [ABSTRACT FROM AUTHOR]

Aims To validate whether the anti-cancer effect of micro RNA-122 ( miR-122) on hepatocellular carcinoma ( HCC) is mediated through regulating Wnt/β-catenin signalling pathways. Methods The expression levels of miR-122 in HCC tissues and varied hepatoma cells were quantified by real-time PCR. MiR-122 agomir was transfected into HepG2, Hep3B cells to over-express miR-122. The effect of over-expression miR-122 on proliferation and apoptosis of HepG2 and Hep3B cells was evaluated using CCK-8 kit and flow cytometer respectively. The 3′- UTR segments of Wnt1 containing the miR-122 binding sites were amplified by PCR and the luciferase activity in the transfected cells was assayed. Wnt1 mRNA level was quantified using RT-PCR. Protein levels of Wnt1, β-catenin and TCF-4 were detected using Western blotting. Results In comparison with the expression level of miR-122 in para-cancerous tissues or Chang liver cell, the expression level in HCC tissues or varied hepatoma cells was significantly decreased ( P < 0.05). Over-expression of miR-122 significantly inhibited the proliferation ( P < 0.05), and promoted the apoptosis of HepG2 and Hep3B cells. Over-expressed miR-122 down-regulated the protein levels of Wnt1, β-catenin and TCF-4 ( P < 0.05). MiR-122 suppressed the luciferase activity of the pmiR-Wnt1-wt by approximately 50% compared with the negative control, while mutation or removal of the miR-122 binding site using si RNA or mir-122 inhibitor blocked the suppressive effect ( P < 0.05). Conclusions MiR-122 expression is down-regulated in human HCC. Over-expression of miR-122 inhibits HCC cell growth and promotes the cell apoptosis by affecting Wnt/β-catenin- TCF signalling pathway. [ABSTRACT FROM AUTHOR]