MiR-449a functions as a tumor suppressor in endometrial cancer by targeting CDC25A

Accumulating evidence has demonstrated that microRNAs (miRNAs) play critical roles in cancer initiation and development by functioning either as oncogenes or as tumor suppressors. The role of microRNA-449a (miR-449a) in endometrial cancer remains unclear. We examined the levels of miR-449a and miR-449b in benign endometrium, type I and type II endometrial cancer tissues by quantitative real-time polymerase chain reaction. To further investigate the roles of miR-449a in regulating the behavior of endometrial cancer cells, we overexpressed miR-449a in the endometrial cancer cell line HEC-1B, which had low endogenous miR-449a expression. We analyzed the effects of miR-449a overexpression on CDC25 expression, proliferation, invasion and apoptosis of HEC-1B cells. We found that miR-449a and miR-449b levels were markedly reduced in type II endometrial cancer tissues but not in type I endometrial cancer tissues compared with normal endometrium. Overexpression of miR-449a significantly inhibited the proliferation, invasion and clonogenic survival of HEC-1B cells. MiR-449a overexpression also induced apoptosis in HEC-1B cells. In addition, real-time RT-PCR and western blot analysis showed that CDC25A expression was suppressed by miR-449a overexpression. Our results suggest that miR-449a may act as a tumor suppressor by targeting CDC25A in endometrial cancer.