Novel, non-invasive biomarkers with high sensitivity and specificity are critical for breast cancer treatment, and prognosis. MicroRNA (miR)-96 has been demonstrated to be highly expressed in several solid malignancies, including breast cancer. However, its expression and function in the metastasis and prognosis of breast cancer have not been fully explored, and its regulation mechanisms remain unclear. In the present study, the serum miR-96 expression in healthy controls, benign and malignant breast cancer types was compared by using reverse transcription-quantitative polymerase chain reaction. The effect of chemotherapy on miR-96 expression in breast cancer was also investigated. Result revealed that miR-96 expression was increased in malignant breast cancer types and reduced in patients following chemotherapy treatment. The effect of miR-96 manipulation on the migration of breast cancer cells was also investigated by using wound healing, and Transwell migration assays. These results revealed that the induced expression of miR96 led to enhanced wound closing and trans-membrane cell numbers. By using bioinformatics analysis, western blotting and immunohistochemical staining, the metastasis suppressor-1 (MTSS1) gene was identified to be the functional target of miR-96 in the promotion of cell migration. In conclusion, it was identified that miR-96 exhibited an increased level in serum samples of patients with malignant breast cancer in comparison with benign breast tumor types and health controls and may be substantially reduced by chemotherapy treatment, implying that it may be used as a prognostic marker in breast cancer. miR-96 overexpression may inhibit migration of breast cancer cells by downregulating MTSS1 expression.
Keywords: breast cancer; metastasis; metastasis suppressor-1; microRNA-96.