Objective: To investigate the expression of miR-130b in human hepatocellular carcinoma (HCC) and its correlations with clinical-pathological features.
Methods: Real-time quantitative PCR (qRT-PCR) was applied to detect the expression of miR-130b in HCC tissues (n=86), matched normal tumor-adjacent tissues and 5 HCC cell lines (LO2 human normal hepatocytes, HepG2, Hep3B, SMMC-7721, Hu7 cells). The expressions of peroxisome proliferator-activated receptor γ (PPARγ), E-cadherin and vimentin were measured by immunohistochemistry. miR-130b inhibitor synthesized artificially was transfected into SMMC-7721 cells in vitro. Cell invasion was analyzed by Transwell(TM) assay. The expressions of PPARγ, E-cardhern and vimentin in SMMC-7721 cells after transfected with miR-130b inhibitor and PPARγ siRNA were detected by qRT-PCR and Western blotting.
Results: The expression of miR-130b mRNA in HCC tissues was significantly higher than that in matched normal tumor-adjacent tissues. Clinical analysis indicated that high expression of miR-130b was prominently correlated with venous infiltration, high Edmondson-Steiner grading and advanced tumor node metastasis (TNM) stage. Elevated miR-130b expression was observed in all HCC cell lines (HepG2, SMMC-7721, Huh7 and Hep3B) as compared with that in LO2 nontransformed hepatic cell line. Furthermore, there was an inverse correlation between miR-130b and E-cadherin as well as between miR-130b and PPARγ, and a positive correlation between miR-130b and vimentin was demonstrated in HCC tissues. miR-130b inhibitor could significantly increase the expression of PPARγ and E-cadherin, but decrease the expression of vimentin in SMMC-7721 cells, meanwhile it suppressed the migration and invasion of SMMC-7721 cells. In addition, the down-regulation of PPARγ expression by PPARγ siRNA partially abrogated the above effect of miR-130b on HCC cells.
Conclusion: The expression of miR-130b in HCC tissues is significantly higher than that in tumor-adjacent tissues. The increased expression of miR-130b is related with the malignant manifestations of HCC. miR-130b may promote HCC cell invasion by inhibiting PPARγ expression and inducing epithelial-mesenchymal transition.