Objectives To evaluate the expression profile of myoD microRNA-29 （miR-29） family in L6 myoblast differentiated to myotube or L6 myotube treated by glucose and insulin, and to further probe the molecular mechanism of myoD regulating the expression of miR-29 clusters.
Objective To investigate the expression profile of microRNA-21 in human cholangiocarcinoma tis- sues and to validate its bona fide targets in human cholangiocarcinoma cells. Methods The expression profile of microRNA-21 in human cholangiocarcinoma tissues and cholan- giocarcinoma cell line, QBC939, was evaluated by using real-time PCR analysis. The bona fide targets of microRNA-21 were analyzed and confirmed by dual luciferase reporter gene assay and western blot, respec- tively. The expressional correlation of microRNA-21 and its targets was probed in human cholangiocarci- noma tissues by using real-time PCR, locked nucleic acid in situ hybridization （LNA-ISH）, and immunohis- tochemistry analysis. Results Real-time PCR analysis revealed that microRNA-21 expression depicted a significant up-regulation in human cholangiocarcinoma tissues about 5.6-fold as compared to the matched normal bileduct tissues （P〈0.05）. The dual luciferase reporter gene assay revealed endogenous microRNA-21 in cholan- giocarcinoma cell line, QBC939, inhibited the luciferase reporter activities of wild-type PTEN （P〈0.01） and PDCD4 （P〈0.05） and had no this effect on mutated PTEN and PDCD4. Moreover, loss of microRNA-21 function led to a significant increase of PTEN and PDCD4 protein levels in QBC939 cells. Elevated microRNA-21 levels were accompanied by marked reductions of PTEN and PDCD4 expression in the same cholangiocarcinoma tissue. Conclusion microRNA-21 expression is up PDCD4 are direct effectors of microRNA-21. regulated in human cholangiocarcinoma and PTEN,
