[Effect of microRNA-mediated p65 gene silencing on the proliferation and apoptosis of human breast cancer MDA-MB-231 cells].

OBJECTIVE: To explore the effect of microRNA (miRNA)-mediated p65 gene knockdown on the proliferation and apoptosis of human breast cancer MDA-MB-231 cells. METHODS: p65-targeted miRNA plasmid was constructed and transfected into MDA-MB-231 cells via lipofectamine(TM)2000. The expression of p65 gene in the transfected cells at the mRNA and protein levels were detected by RT-PCR and Western blotting, respectively. The cell proliferation and apoptosis were measured by MTT assay and flow cytometry (FCM), respectively. The expressions of apoptosis-related proteins were detected by Western blotting in the transfected cells. RESULTS: Compared with the negative control group, the expressions of p65 mRNA and protein in p65miRNA-trasnfected cells were significantly down-regulated (P<0.05). MTT assay showed significantly lowered viability of MDA-MB-231 cells after the transfection (P<0.05). FCM showed an increased cell apoptosis rate in p65miRNA group compared with that in the negative control group (P<0.05). Caspase-3 and PARP were both cleaved into their active forms and the expression of these active forms was increased in p65miRNA group. CONCLUSION: The miRNA targeting p65 gene can inhibit the proliferation and induce apoptosis of breast cancer cells, and p65 gene might become a new target in gene therapy for human breast cancer.