Downregulation of miR-182-5p inhibits the proliferation and invasion of triple-negative breast cancer cells through regulating TLR4/NF-κB pathway activity by targeting FBXW7

BACKGROUND: To investigate the role of miR-182-5p in the proliferation and invasion of triple-negative breast cancer (TNBC) cells, as well as the underlying mechanism. METHODS: qRT-PCR was used to detect the level of miR-182-5p in tissues and cells. CCK-8 assay, flow cytometry, and Transwell assay were performed to detect cell proliferation, apoptosis rate, and invasion, respectively. Pearson correlation analysis was used to determine the correlation between miR-182-5p and its predicted target gene FBXW7, and the target of miR-182-5p was identified by dual-luciferase reporter gene assay. ELISA assay was used to examine the levels of cytokines in the culture supernatant of tumor cells. Western blot analysis was used to detect the expressions of FBXW7, TLR4, and NF-κB) pathways in tumor cells. RESULTS: In MDA-MB-231 and BT-549 cells, downregulation of miR-182-5p significantly inhibited cell proliferation and invasion and promoted tumor cell apoptosis. Pearson correlation analysis showed that miR-182-5p had a negative correlation with FBXW7. Dual-luciferase reporter gene assay showed that miR-182-5p could directly target FBXW7. Further studies showed that FBXW7 overexpression significantly inhibited cell proliferation and invasion and increased the apoptosis rate. Downregulation of miR-182-5p significantly reduced the levels of TNF-α, IL-1 β, IL-6, and IL-18 in the culture supernatant, and decreased the activity of TLR4/NF-κB pathway in tumor cells, while downregulation of FBXW7 significantly inhibited the effect of miR-182-5p on tumor cells. CONCLUSIONS: Downregulation of miR-182-5p inhibits TLR4/NF-κB pathway activity by increasing FBXW7 expression, thereby suppressing the proliferation and invasion of TNBC cells.