miR-20a induces cell radioresistance by targeting PTEN in hepatocellular carcinoma / 中华放射肿瘤学杂志

ABSTRACT

Objective To explore the role and mechanism of miR-20a in the radiosensitivity of hepatocellular carcinoma (HCC). Methods The expression level of miR-20a in HCC cell lines and tissue specimens was detected by real-time fluorescent quantitative PCR.HCC cell line stably over-expressing miR-20a was constructed. The effect of miR-20a on HCC cell radiosensitivity was evaluate by cloning assay. The expression levels of Bcl-2,Caspase-3 and γ-H2AX proteins were quantitatively detected by Western blot. The target gene of the downstream regulation of miR-20a was predicted by bioinformatics analysis,which was further verified by dual luciferase reporter assay,real-time fluorescent quantitative PCR and Western blot. HCC cell line stably overexpressing miR-20a was transfected with pCDNA3. 0-PTEN to investigate the changes in the radiosensitivity of cells and to determine whether PTEN is a functional target gene for miR-20a-induced radioresistance of HCC. Results The expression levels of miR-20a was significantly up-regulated in HCC cell line and tissue specimens ( both P< 0. 05). After identical radiotherapy, the cell survival rate,the radioresistance was strengthened ( P< 0. 05),the expression of Bcl-2 was up-regulated, whereas the expression levels of Caspase-3 and γ-H2AX were down-regulated in the LV-miR-20a group compared with those in the blank and control groups ( WT and LV-con groups). Overexpression of PTEN could reverse the miR-20a-induced radioresistance. Conclusion miR-20a is up-regulated in the HCC cell lines and tissue specimens. Overexpression of miR-20a can promote the radioresistance of HCC cells. PTEN is a functional target gene for miR-20a-induced radioresistance of HCC,indicating that miR-20a/ PTEN site may be an effective molecular target associated with clinical radiotherapy for liver cancer.