Silencing RhoA inhibits migration and invasion through Wnt/β-catenin pathway and growth through cell cycle regulation in human tongue cancer

Ras homolog gene family member A （RhoA） has been iden- tified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechan- isms underlying growth, migration, and invasion of squa- mous cell carcinoma of tongue （TSCC）. Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 （Gal-3）, β-catenin, and matrix metalloproteinase-9 （MMP-9） in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21clel/WArl, and p27 kiap 1 protein levels. Immunohistochemical assess- ments were performed to further prove the alteration of Gal-3 and β-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gai-3, β-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21 CIPI/WAFI and p27Kiap 1. In vitro, RhoA knockdown also led to inhibition of cell migration, in- vasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migra- tion and invasion through Wnt/β-catenin signaling pathway and cell proliferation through cell cycle regulation, respecti- vely. RhoA might be a novel therapeutic target of TSCC.