Silencing IGF-II impairs C-myc and N-ras expressions of SMMC-7721 cells via suppressing FAK/PI3K/Akt signaling pathway

Emerging evidence confirms that insulin-like growth factor -II (IGF-II), oncogenes C-myc and N-ras are an essential regulator for development and growth in hepatocellular carcinoma (HCC). Although our previous study also indicated that IGF-II might upregulate levels of oncogenes C-myc and N-ras in hepatoma carcinoma cells, the molecular mechanism had not been fully elucidated. Herein, we successfully silenced IGF-II expression in SMCC-7721 cells by small RNA interference. Functional analysis showed that knockdown of IGF-II significantly suppressed growth and proliferation of SMMC-7721 cells and decreased C-myc and N-ras mRNA and protein levels. And this function was mediated by the FAK/PI3K/Akt signaling pathway. Taken together, IGF-II siRNA inactivates the FAK/PI3K/Akt signaling pathway, and further reduces cell proliferation, N-ras and C-myc levels in SMMC-7721 cells. Especially, understanding the relationship between IGF-II and oncogenes N-ras and C-myc in cancer cells will provide novel clues for clinic HCC treatment in the future.