Effect of down-regulation of lncRNA LINC00263 targeting miR-4458 on regulating radiosensitivity of breast cancer SK-BR-3 cells / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the effect of down-regulating lncRNA LINC00263 targeting miR-4458 on the proliferation, migration, invasion and radiosensitivity of breast cancer SK-BR-3 cells.Methods:The expression differences of LINC00263 in breast cancer tissues, adjacent tissues, normal breast epithelial cells and breast cancer cells were determined by qRT-PCR. Transfection of LINC00263 shRNA in breast cancer SK-BR-3 cells down-regulated the expression of LINC00263, and the cloning experiment was used to detect the radiosensitivity. Breast cancer SK-BR-3 cells were treated with 6 Gy irradiation. CCK-8 assay was employed to detect cell proliferation. Flow cytometry was adopted to detect cell apoptosis. Transwell chamber test was performed to detect cell migration and invasion. Western blot was used to detect the expression levels of C-Caspase-3 and C-Caspase-9, MMP-2 and MMP-9 proteins. Bioinformatics software predicted that LINC00263 and miR-4458 had complementary binding sites, and the luciferase reporter system was utilized determine the targeting relationship between LINC00263 and miR-4458. LINC00263 shRNA and miR-4458 inhibitor were co-transfected into breast cancer SK-BR-3 cells, and 6 Gy irradiation was given to detect the changes in cell proliferation, apoptosis, invasion and migration.Results:The expression level of LINC00263 in breast cancer tissues was higher than that in adjacent tissues. The expression level of LINC00263 in breast cancer cells was higher compared with that in normal breast epithelial cells. The radiosensitivity of breast cancer SK-BR-3 cells was increased after transfection of LINC00263 shRNA. Transfection of LINC00263 shRNA and radiation exerted a synergistic effect, jointly inhibited breast cancer cell proliferation, migration and invasion, promoted cell apoptosis, up-regulated the expression levels of C-Caspase-3 and C-Caspase-9 proteins in cells, and down-regulated those of MMP-2 and MMP-9 proteins. Down-regulation of LINC00263 targetedly up-regulated miR-4458 expression. miR-4458 inhibitor reversed the inhibitory effect of LINC00263 shRNA combined with radiation on the proliferation, migration, invasion and apoptosis promotion of breast cancer SK-BR-3 cells.Conclusion:Down-regulating lncRNA LINC00263 targeting miR-4458 inhibits the proliferation, migration and invasion of breast cancer SK-BR-3 cells, and improves cell radiosensitivity.