Study On The Correlation Between Expression Of MicroRNAs And Hepatocellular Carcinoma Chemotherapy And Muscle Cell Differentiation

Aims:Increasing evidence has revealed that deregulated microRNAs function as oncomiRs or tumor suppressors in diverse cancers. However, the role of specific microRNAs in predicting the clinical benefit of chemotherapy has not been well-established, and the targeted genetic pathways of chemotherapeutic drugs remain unclear. Here, we investigated the correlation between microRNA-21expression and hepatic arterial infusion chemotherapy with5-fluorouracil and pirarubicin (HAIC) prevention for hepatocellular carcinoma (HCC) and identified an microRNA-21-mediated program as a critical HAIC target in HCC treatment. Methods: We used quantitative real-time PCR to measure the levels of mature and primary microRNA-21in HCC cells treated with cisplatin,5-fluorouracil, or pirarubicin as well as in HCC tissue samples (n=148). Apoptosis and in vitro invasion assays were performed following chemotherapeutic drug treatment to evaluate cell growth and invasion in HCC cells transfected with microRNA-21mimic or inhibitor. Immunoblot and immunohistochemistry analyses were conducted to determine the correlations among activating protein-1(AP-1), microRNA-21, and its targets in HCC cells and tissue specimens. Results:We found that HCC patients with low microRNA-21levels in tumors tended to have a longer time to recurrence and disease-free survival. Enforced microRNA-21expression resulted in chemoresistance, and microRNA-21inhibition improved chemosensitivity in HCC cells. Moreover, The AP-1/microRNA-21-mediated axis is a target genetic pathway of chemotherapy in HCC. Conclusions:microRNA-21is a prognostic biomarker for HCC patients undergoing HAIC. Targeting microRNA-21enhanced the effect of chemotherapeutic drugs, thereby suggesting that microRNA-21suppression in combination with HAIC may be a novel approach for HCC treatment. Objectives To evaluate the expression profile of myoD microRNA-29(miR-29) family in L6myoblast differentiated to myotube or L6myotube treated by glucose and insulin, and to further probe the molecular mechanism of myoD regulating the expression of miR-29clusters. Methods The expression of myoD and miR-29family was detected by using real-time PCR and Western blot analysis. The potential promoter and transcription factors binding sites of miR-29clusters were predicted by Promoter scan and transcriptional factor search. The promoter sequence of miR-29b1-a and miR-29b2-c cluster was cloned into a luciferase reporter plasmid and the regulatory effect of myoD was analyzed by using dual luciferase reporter assay. Electrophoretic mobility shift assay was further conducted to indicate the binding of myoD on specific sequence. Moreover, overexpression of myoD was achieved by a recombinant adenovirus system (Ad-myoD). L6cells were infected with Ad-myoD and real-time PCR was conducted to analyze the expression of miR-29b and miR-29c. Results The expression levels of myoD, miR-29a, miR-29b, and miR-29c were increased in L6myoblast differentiated to myotube. The expression of myoD, miR-29b, and miR-29c was up-regulated in L6myotube treated with glucose and insulin, but miR-29a depicted no significant change. Dual luciferase reporter gene assay showed that myoD functioned as a positive regulator of miR-29b2-c expression and myoD could bind to the specific sequence located at the promoter region of miR-29b2-c cluster. Enforced expression of myoD led to a marked increase of miR-29b and miR-29c levels in L6cells. Conclusions Expression of microRNA-29b2-c Cluster is Positively Regulated by MyoD in L6Cells.