Influence of miRNA-21 in radiosensilivity of breasl cancer cells and ils mechanism / 吉林大学学报(医学版)

ABSTRACT

Objective: To observe the influence of miRNA-21 in the radiosensitivity of the breast cancer cells, and to preliminarily explore its mechanism. Methods: The breast cancer T47D and MDA-MB-361 cells were irradiated with 0. 0. 2.5. and 5. 0 Gy y-ray. respectively; CCK8 assay was used to detect the survival rates of T47D and MDA-MB-361 cells and flow cytometry was used to analyze the cell cycle; real-time quantitative PCR was used to detect the expression levels of miRNA-21 in cells during 72 h. The T47D and MDA-MB-361 cells were transfected with anti-miRNA-21 sequence (anti-miRNA-21 group) and negative control sequence (negative control group)∗ respectively; the untransfected cells were set as blank control group. Real-time quantitative PCR was used to detect the expression levels of miRNA-21 in cells in various groups. After irradiation with 0. 0 and 5. 0 Gy y-ray. CCK8 assay was used to detect the survival rates, and flow cytometry was used to analyze the cell cycle. Results: After irradiation with 5. 0 Gy y-ray. the survival rate of T47D cells was significantly higher than that of the MDA-MB-361 cells (PC0.05). Compared with 0. 0 Gy radiation group, the percentages of T47D and MDA-MB-361 cells in GM phase in 5.0 Gy radiation group were significantly increased (PC0.05); the miRNA-21 expression levels in the T47D and MDA-MB-361 cells were significantly increased ( P< 0. 05). The miRNA-21 expression levels in the T47D and MDA-MB-361 cells in anti-miRNA-21 group were lower than those in blank control group (P<0. 05). After irradiation with 5. 0 Gy y-ray. the survival rates of T47D and MDA-MB-361 cells in anti-miRNA-21 group were significantly lower than those in blank control group ( P<.0. 05 or P<0. 01) . and the percentage of T47D cells in G2/M phase in anti-miRNA-21 group was significantly lower than that in blank control group ( P<0. 05). and the percentage of T47D cells in subG. phase was significantly higher than that in blank control group ( P<0. 05). Conclusion: The down-regulation of miRNA-21 may enhance the radiosensitivity of breast cancer cells, and its mechanism may be related to the inhibition of G?/M phase arrest.