Rho GDP dissociation inhibitor beta promotes cell proliferation and invasion by modulating the AKT pathway in hepatocellular carcinoma.

Rho GDP dissociation inhibitor (GDI) beta, (RhoGDI2), has been identified as a proto-oncogene that is upregulated in human cancers, but the role of RhoGDI2 in hepatocellular carcinoma (HCC) remains unclear. In the present study, we investigated the RhoGDI2 expression level in HCC tissues and the function of RhoGDI2 in HCC cell growth and metastasis. We examined the RhoGDI2 mRNA expression level in 64 sets of HCC tissue and their adjacent nontumor tissue counterparts using quantitative real-time polymerase chain reaction. In vitro proliferation and invasion assays were conducted to determine the effect of RhoGDI2 on the ability of HCC cells to proliferate and invade, respectively. Western blot analysis was conducted to examine expression levels of RhoGDI2p-AKT, MMP-2, and MMP-9 in HCC cells. RhoGDI2 mRNA was significantly overexpressed in the HCC specimens compared with the nonneoplastic liver specimens, and the RhoGDI2 mRNA and protein levels were higher in the HCC cell lines, especially the highly metastatic cell lines 97L and 97H. To further investigate the role that RhoGDI2 plays in HCC, we overexpressed RhoGDI2 using a lentivirus-mediated overexpression technique in two HCC cell lines (Huh7 and 7721) that endogenously express a low level of RhoGDI2. Stable cells overexpressing RhoGDI2 demonstrated a significant increase in cell proliferation and invasion. Furthermore, our additional findings indicated that RhoGDI2-mediated cellular invasion requires the PI3K/Akt signaling-dependent expression of matrix metalloproteinases (MMPs). Our findings suggest that RhoGDI2 plays an important role in HCC growth and invasion and should be considered a novel HCC therapeutic target candidate.