MicroRNA (miR)-146a-5p functions as a tumor suppressor in various types of cancer. However， the role of miR-146a-5p in the development of triple-negative breast cancer (TNBC) is unclear. The present study aimed to investigate the role of miR-146a-5p in TNBC. The expression level of miR-146a-5p in TNBC tissues and cell lines was initially detected using reverse transcription-quantitative polymerase chain reaction. To predict the target gene of miR-146a-5p， TargetScan software was used and a dual luciferase assay was performed to verify the prediction. Furthermore， in order to explore the role of miR-146a-5p in TNBC， miR-146a-5p was overexpressed in TNBC cells using miR-146a-5p mimics. An MTT assay was pe... More
MicroRNA (miR)-146a-5p functions as a tumor suppressor in various types of cancer. However， the role of miR-146a-5p in the development of triple-negative breast cancer (TNBC) is unclear. The present study aimed to investigate the role of miR-146a-5p in TNBC. The expression level of miR-146a-5p in TNBC tissues and cell lines was initially detected using reverse transcription-quantitative polymerase chain reaction. To predict the target gene of miR-146a-5p， TargetScan software was used and a dual luciferase assay was performed to verify the prediction. Furthermore， in order to explore the role of miR-146a-5p in TNBC， miR-146a-5p was overexpressed in TNBC cells using miR-146a-5p mimics. An MTT assay was performed to detect cell proliferation， and a Transwell assay was conducted to determine cell migration and invasion. Furthermore， western blotting was performed to measure associated protein expression. It was revealed that miR-146a-5p was downregulated in TNBC tissues and cell lines. SOX5 was indicated to be a target gene of miR-146a-5p and was upregulated in TNBC cells. Additionally， miR-146a-5p could inhibit TNBC cell proliferation， migration and invasion， repress the expression of mesenchymal markers (N-cadherin， vimentin and fibronectin) and increase epithelial marker (E-cadherin) expression. Furthermore， SOX5 overexpression eliminated the effects of miR-146a-5p mimics on TNBC cells. In conclusion， the data of the present study indicated that miR-146a-5p inhibits the proliferation and metastasis of TNBC cells by regulating SOX5.
