Aims: To investigate the effect of miR-195 overexpression on radiosensitivity and the relevant molecular mechanisms in breast cancer.
Methods: miR-195 mimics were transfected to breast cancer cell line MCF-7 by gene transfection; miR-195 expression level in cells was determined by real-time quantitative PCR. Cellular viability was observed by colony formation assay after the cells were irradiated with X-ray. Apoptosis was detected by annexin V/propidium iodide (PI) staining. Protein expression was evaluated by Western blot assay.
Results: After miR-195 mimics were transfected, miR-195 expression in breast cancer cells was significantly upregulated (P < 0.05). miR-195 overexpression significantly enhanced the response to radiation of MCF-7 cells with a decrease in colony survival at individual doses of X-ray (P < 0.05). After the cells were irradiated with 5 Gy, apoptotic rate was significantly increased in miR-195-overexpressed group with a rate of 18.13% ± 1.57%; moreover, BCL-2 protein expression was significantly downregulated (P < 0.05).
Conclusion: Exogenetic miR-195 expression could significantly enhance the radiosensitivity of human breast cancer cells; this finding may be attributed to BCL-2 downregulation to promote radiation-induced apoptosis.
Keywords: Breast cancer; apoptosis; miR-195; radiosensitivity.