miR‑31‑5p may enhance the efficacy of chemotherapy with Taxol and cisplatin in TNBC

The limited efficacy of chemotherapy with Taxol (TAX) and cisplatin (DDP) in triple‑negative breast cancer (TNBC) has prompted the investigation of combined therapies. Previous studies demonstrated that microRNA (miR)‑31‑5p is involved in various biological processes. In the present study, it was hypothesized that the overexpression of miR‑31‑5p may enhance the efficacy of chemotherapy. The expression levels of miR‑31‑5p in the TNBC cell lines MDA‑MB‑231 and MDA‑MB‑468 were measured using reverse transcription‑quantitative PCR following transfection with miR‑31‑5p mimic or inhibitor. A Cell Counting Kit‑8 and flow cytometry assays suggested that the overexpression of miR‑31‑5p inhibited cell proliferation and promoted apoptosis, and these effects were reversed by transfecting a miR‑31‑5p inhibitor into MDA‑MB‑231 and MDA‑MB‑468 cells. Furthermore, the overexpression of miR‑31‑5p increased the sensitivity of cells to chemotherapy, which exhibited an increase in apoptosis and in the expression level of Bax, and a decrease in the expression level of Bcl‑2. Chemotherapy resistance induced by miR‑31‑5p inhibitor could be reversed by inhibiting the AKT signaling pathway in MDA‑MB‑231 and MDA‑MB‑468 cells. In conclusion, the present preclinical results indicated that targeting miR‑31‑5p may enhance the efficacy of TAX‑ and DDP‑mediated chemotherapy in TNBC.