It is well known that microRNAs (miRNAs) play important roles in cancer development by targeting oncogenes or tumor-suppressor genes. However, little is known regarding the mechanisms of miR-30c action in endometrial cancer. In this study, we aimed to determine whether miR-30c targets metastasis-associated gene-1 (MTA1) and acts as a tumor suppressor in endometrial cancer cell lines Ishikawa (estrogen receptor-positive, ER+) and HEC-1-B (ER-) by down-regulating MTA1. As a result, in both Ishikawa and HEC-1-B cells, real-time PCR demonstrated that overexpression of miR-30c led to the down-regulation of MTA1 mRNA (P<0.05), while Western blotting confirmed the reduced expression levels of MTA1 protein (P<0.01). A dual-luciferase reporter assay demonstrated that miR-30c was directly bound to the 3'-untranslated regions of MTA1. Then we studied the biological mechanisms of endometrial cancer cells transfected with the Pre-miR-30c plasmid. MTT assay and growth curves revealed that miR-30c inhibits both Ishikawa and HEC-1-B cell proliferation. However, we did not see obvious differences in rates of apoptosis between miR-30c-overexpressing and the negative control cells. Then using wound-healing and Matrigel invasion assays, we found that the migratory and invasive abilities of cells transfected with the Pre-miR-30c plasmid were significantly suppressed compared with the control cells (P<0.01). Overall, our study, for the first time, showed that MTA1 is negatively regulated by miR-30c and that overexpression of miR-30c inhibits the proliferative, migratory and invasive abilities of endometrial cancer cells. These results suggest that miR-30c acts as a tumor suppressor and negatively regulates endometrial cancer cells by targeting MTA1.

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