[RNAi-mediated gene silencing of livin synergistic with epirubicin enhance apoptosis of human breast cancer cells].

OBJECTIVE: To observe the effects of silencing of livin gene expression combined with anthracycline chemotherapy on the apoptosis of human breast cancer cells.

METHODS: Double stranded RNA (dsRNA) targeting the livin gene was chemically synthesized in vitro and transfected into human breast cancer cells of the line ZR-75-30 mediated by lipofectamine 2000. The transfection efficiency was observed by fluorescence confocal microscopy. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression of livin at mRNA and protein levels. ZR-75-30 cells transfected with dsRNA targeting livin for 24 h were treated with 50 microg/ml epirubicin for 12 h, flow cytometry was used to detect the apoptosis rate of the cells.

RESULTS: The livin mRNA expression rates of the livin-siRNA transfected group was (29.68 +/- 2.7)%, with an inhibitory rate of 53.66%, significantly lower than those of the negative control and blank control groups [(52.01 +/- 2.9)% and (51.95 +/- 3.1)% respectively, both P < 0.01]. The livin protein expression rate of the livin-siRNA group was (27.80 +/- 2.1)%, significantly lower than those of the negative control siRNA group and blank control group [(53.80 +/- 3.0)% and (55.12 +/- 2.8)% respectively, both P < 0.01]. 36 h after the treatment of siRNA against livin combined with epirubicin the apoptosis rate was (15.18 +/- 0.05)%, significantly higher than those of the negative control group and blank control group [(2.78 +/- 0.08)% and (2.65 +/- 0.12)% respectively, both P < 0.01].

CONCLUSIONS: Sequence specific siRNA targeting livin synergistic with epirubicin is capable of enhancing the apoptosis rate of human breast cancer cells. Silencing of livin gene expression with siRNA combined with anthracycline chemotherapy may hold great promise as a novel therapy for livin expressing breast cancer.