Abstract:

Objective   To investigate the effect of miRNA-152 （miR-152） on adriamycin sensitivity of breast cancer cells and its mechanism. Methods  The levels of miR-152 in human breast epithelial cell line HBL-100， human breast cancer MCF-7 cells and adriamycin resistant MCF-7／ADR cells were detected by real-time quantitative PCR （QPCR）. MCF-7 and MCF-7／ADR cells were transfected with miR-152 mimics （overexpression group） or negative control （negative control group）， and no transfection was used as blank control group. The expression of miR-152 in MCF-7 cells and MCF-7／ADR cells after transfection were detected by QPCR. The proliferation of cells treated with different concentrations of adriamycin（10, 50, 100, 200 and 500 ng/ml） was detected by MTT， and the apoptotic rate after transfection was detected by flow cytometry. Western blotting was used to detect the protein level of phosphatidylinositol-3-kinase catalytic subunit α （PIK3CA）. The target regulation of miR-152 on PIK3CA was evaluated by the double luciferase report test. Results  QPCR Results  showed that miR-152 levels in MCF-7 cells and MCF-7／ADR cells were all lower than those in HBL-100 cells， and miR-152 levels in MCF-7／ADR cells were lower than that in MCF-7 cells （P＜0.05）. The levels of miR-152 after transfection in overexpression group were higher than those in the negative control group and the blank control group （P＜0.05）. Compared with other two groups， the survival rate and the PIK3CA protein level of the overexpression group decreased and the apoptotic rate increased （P＜0.05）. MiR-152 could inhibite the luciferase activity of the wild-type PIK3CA 3’UTR reporter gene， but had no effect on the luciferase activity of the mutant PIK3CA 3’UTR. Conclusion  The expression of miR-152 is decreased in breast cancer cells， and is related to adriamycin resistance in breast cancer cells. It is involved in the proliferation and apoptosis process of breast cancer cells， and plays an important role in reversing the drug resistance of breast cancer.

Key words: Breast cancer, MicroRNA-152, Phosphatidylinositol-3-kinase catalytic subunit α（PIK3CA）, Adriamycin