MicroRNA-409 may function as a tumor suppressor in endometrial carcinoma cells by targeting Smad2

Abstract

MicroRNAs (miRNAs) are frequently dysregu-lated in human cancer and can act as either potent oncogenes or tumor suppressor genes. The aberrant expression of miRNA-409 (miR-409) has been found in certain types of cancer, however, its expression and potential biological role in endometrial cancer remain to be fully elucidated. In the present study, a total of 16 pairs of tissue samples from 16 patients with endometrial cancer were used in the present study, each of which consisted of human endometrial cancer tissue and matched adjacent normal tissue from the same patient. The expression of miR-409 of the tissue were detected and its associations with Ishikawa and HEC-1B human endometrial cancer cell lines were studied. The results of the present study demonstrated that miR-409 was downregulated in human endometrial cancer, and it suppressed the growth of Ishikawa and HEC-1B human endometrial cancer cell lines. Bioinformatics analysis indicated that small mothers against decapentaplegic 2 (Smad2) was a putative target of miR-409. In a luciferase reporter system, it was confirmed that Smad2 was a direct target gene of miR-409. It was also demonstrated that Smad2 was upregulated in human endometrial cancer tissues, and this was inversely correlated with the expression of miR-409. These findings indicated that miR-409 targeted the Smad2 transcript and suppressed endometrial cancer cell growth, suggesting that miR-409 has a tumor suppressive role in the pathogenesis of human endometrial cancer.