MicroRNA-145 functions as a tumor suppressor by targeting matrix metalloproteinase 11 and Rab GTPase family 27a in triple-negative breast cancer.

Although increasing evidence has documented that microRNA-145 (miR-145) acts as a tumor suppressor in breast cancer, its exact role in triple-negative breast cancer (TNBC) remains poorly defined. In this study, the expression of miR-145 in human TNBC cells and samples from 30 patients was analyzed by stem-loop real-time PCR. We found that miR-145 was significantly downregulated in TNBC tissues and cells. Upregulating miR-145 in HCC1937 cells dramatically suppressed cell proliferation and induced G1-phase arrest, whereas MDA-MB-231 cells did not show growth inhibition. MiR-145 exhibited an inhibitory role in cell invasion through the post-transcriptional regulation of the novel targets MMP11 and Rab27a in TNBC cells. Additionally, miR-145 silencing could be reversed by 5-aza-2'-deoxycytidine (DAC). These results demonstrated that miR-145 has an inhibitory role in TNBC malignancy by targeting MMP11 and Rab27a, which might be potential therapeutic and diagnostic targets for TNBC.