microRNA-616在肝细胞癌侵袭转移中的作用机制研究

Expression of miR-616 in human hepatocellular carcinoma and its effect on tumor invasion and metastasis

目的探讨microRNA-616(miR-616)在肝细胞癌(HCC)中的表达及其在HCC侵袭转移中的作用机制。方法通过qRT-PCR检测miR-616在60例HCC及癌旁组织中的表达,同时检测miR-616在不同肝癌细胞系中的表达情况;免疫组织化学染色检测miR-616在HCC及癌旁组织中波形蛋白(vimentin)、上皮型钙黏素(E-cadherin)及同源性磷酸酶-张力蛋白(PTEN)的表达情况;qRT-PCR检测miR-616在人正常永生化肝细胞(LO2)及5种不同肝癌细胞系(HepG2、SMMC-7721、Hep3B、Hu7)中的表达水平;使用miR-616抑制物作用Hep3B细胞,Transwell^(TM)实验检测miR-616抑制后Hep3B细胞侵袭能力变化;应用miR-616抑制物及PTEN siRNA转染Hep3B细胞,qRT-PCR检测Hep3B中miR-616、vimentin、PTEN、E-cadherin的mRNA水平,Western blot法检测癌细胞中vimentin、PTEN、E-cadherin的蛋白水平。结果 miR-616在HCC组织中表达水平高于对应癌旁组织;miR-616在不同肝癌细胞系中表达均高于LO2细胞;miR-616高表达与低表达在血管侵犯、Edmonson-Steiner分级、TNM分期比较差异均有统计学意义(均P<0.05);miR-616高表达肝癌组PTEN及E-cadherin水平低于miR-616低表达肝癌组,而vimentin水平高于miR-616低表达肝癌组,相关性分析结果显示HCC组织中miR-616与E-cadherin、PTEN水平呈负相关,与vimentin水平呈正相关;在肝癌细胞中抑制miR-616后PTEN及E-cadherin表达水平上调,而vimentin表达降低,Hep3B细胞的侵袭能力明显降低。结论 miR-616在HCC组织中表达上调,其表达与HCC恶性临床病理特征有关,miR-616促进肝癌细胞侵袭转移的作用可能与其抑制PTEN表达及诱导上皮间质转化有关。

Objective To investigate the expression of miR-616 in human hepatocellular carcinoma and its effects on tumor invasion and metastasis. Methods The expression of miR-616 was detected with real-time quantitative PCR （qRT-PCR） in 60 specimens of hepatocellular carcinoma （HCC） tissues and corresponding adjacent normal tissues; and also in human HCC HepG2, SMMC-7721, Hep3B, Hu75 cells and normal liver LO2 cells. The expression of vimentin, phosphatase, tensin homolog （PTEN） and E-cadherin was detected with immunohistochemical S-P method. The miR-616 inhibitor was transfected into Hep3B cells in vitro, cell invasion was analyzed by Transwell？ assay. The expression of PTEN, E-cardhern and vimentin mRNAs and proteins after transfection was detected by qRT-PCR and Western blotting, respectively. Results The expression of miR-616 in HCC tissues was higher than that in matched tumor-adjacent normal tissues; and it was significantly correlated with venous infiltration, high Edmondson-Steiner grades and lymph node metastasis and TNM tumor stages in HCC. Elevated miR-616 expression was observed in HCC cell lines HepG2, SMMC-7721, Huh7 and Hep3B as compared with that in LO2 hepatic cell line. Furthermore, miR-616 expression was negatively correlated with E-cadherin and PTEN, positively correlated with vimentin in HCC tissues. The miR-616 inhibitor suppressed the migration and invasion in Hep3B cells; and it increased the expression of E-cadherin and PTEN, while decreased the expression of vimentin in Hep3B cells. In addition, down-regulation of PTEN＇ expression partially abrogated the effect of miR-616 inhibitor in HCC cells. Conclusion The expression of miR-616 in HCCtissues is significantly up-regulated, and it can promote proliferation and induce apoptosis of HCC cells by down-regulating the expressions of PTEN.