Rottlerin upregulates DDX3 expression in hepatocellular carcinoma.

Rottlerin has been reported to exert its anti-tumor activity in various types of human cancers. However, the underlying molecular mechanism has not been fully elucidated. In the current study, we explored whether rottlerin exhibits its tumor suppressive function in hepatocellular carcinoma cells. Our MTT assay results showed that rottlerin inhibited cell growth in hepatocellular carcinoma cells. Moreover, we found that rottlerin induced cell apoptosis and caused cell cycle arrest at G1 phase. Furthermore, our wound healing assay result demonstrated that rottlerin retarded cell migration in hepatocellular carcinoma cells. Additionally, rottlerin suppressed cell migration and invasion. Notably, we found that rottlerin upregulated DDX3 expression and subsequently downregulated Cyclin D1 expression and increased p21 level. Importantly, down-regulation of DDX3 abrogated the rottlerin-mediated tumor suppressive function, whereas overexpression of DDX3 promoted the anti-tumor activity of rottlerin. Our study suggests that rottlerin exhibits its anti-cancer activity partly due to upregulation of DDX3 in hepatocellular carcinoma cells.