MiR-664b-3p Inhibited Triple-Negative Breast Cancer Cell Growth Via Targeting BRIP1

Background: Many studies indicate that microRNAs (miRNAs) play a crucial role in modulating the development and progression of triple-negative breast cancer (TNBC). However, miR-664b-3p affections on the TNBC functions and mechanisms are still unknown. The purpose of our study was to clarify the effects of miR-664b-3p in cellular TNBC development and progression. Methods: In our study, the expressions of miR-664b-3p in cell lines and tissueswere tested by real-time PCR (RT-PCR), immunofluorescence, H&E and immunohistochemistry staining. CCK-8 assay, colony formation, EdU, flow cytometry apoptosis, wound scratch, Transwell assays were applied to explore the cell functions. The targeted relationship between miR-664b-3p and its target BRIP1 was determined by dual-luciferase reporter assay and rescue experiments. Results: We observed that miR-664b-3p was significantly decreased in TNBC cell lines. Overexpression of miR-664b-3p could observably inhibit cell proliferation, migration, invasion and induced apoptosis in vitro. Meanwhile, miR-664-3p suppressed TNBC tumor growth in vivo. Furthermore, luciferase reporter assays identified the interaction between 3’UTR of BRIP1 and miR-664b-3p. Moreover, we investigated the mechanisms underlying the effect of miR-664b-3p on cell functions, and the result showed that miR-664b-3p inhibited cell proliferation, invasion and accelerated apoptosis by targeting BRIP1. Conclusion: From the above, our findings indicated that miR-664b-3p played a significant role in TNBC progression by targeting BRIP1, providing new therapeutic targets for diagnostic in TNBC.