Expression of miR-122 mediated by adenoviral vector induces apoptosis and cell cycle arrest of cancer cells.

BACKGROUND: microRNA-122 (miR-122) plays an important role in both of hepatic physiology and pathology. Downregulation of miR-122 was reported in human primary hepatocellular carcinoma (HCC) and restoration of miR-122 could suppress the growth of cancer cells. In this study, we presented a novel strategy for cancer therapy based on gene transfer of miR-122 by adenoviral vector. METHODS: We generated a recombinant adenoviral vector expressing miR-122 (Ad-miR122). The miR-122 expression was measured by quantitative Real-Time PCR (qRT-PCR). Cell survival rate was determined by MTT assay. RESULTS: Our data showed that Ad-miR122 could express functional miR-122 in tumor cells at a high level. Infection of tumor cells with Ad-miR122 resulted in inhibition of growth of cancer cells originating from liver (HepG2, Hep3B, Huh7 and PLC/PRF/5), lung (NCI-H460) and uterine cervix (HeLa). This antitumor activity was related to the induction of apoptosis and/or cell cycle arrest in cancer cells. Infection with Ad-miR122 resulted in decreased expression of Bcl-W and CCNG1 in cancer cells. CONCLUSION: The antitumor activity of Ad-miR122 was probably due to the induction of apoptosis and/or cell cycle arrest in cancer cells through inhibiting Bcl-W and/or CCNG1 expression. We concluded that expression of therapeutic microRNA, such as miR-122, via adenoviral vector is a promising strategy for cancer treatment.