Suppression of Proliferation of MCF- 7 Human Breast Cancer Cell Line by △Np73 RNA Interfering Plasmids

Objective To suppress the expression of △Np73 by RNA interference,observing its effect on the proliferation of human breast cancer cell line MCF- 7. Methods △Np73 expression plasmids were constructed and transfected into human breast cancer cell line MCF- 7 by liposome method. Transfection efficiency was calculated by counting green fluorescent protein expressing cells under fluorescence microscope. Cell growth inhibition rate was detected by MTT assay. △Np73 and TAp73 mRNA expression was measured by real- time PCR. After pcDNA3- HA /DNp73α expression plasmids were co- transfected with △Np73 plasmids,Western Blot test was used to detect △Np73 and TAp73 expression level. Results △Np73 plasmids were successfully constructed and the transfection rate reached 62%. Cell proliferative activity of MCF- 7 was significantly decreased by the transfection of △Np73 siRNA plasmid compared with negative control group. △Np73 siRNA plasmid transfection effectively inhibited endogeneous △Np73 mRNA expression and exogenous △Np73 protein expression,showing no obvious inhibitory effects on TAp73 mRNA protein expression. Conclusion △Np73 siRNA expression plasmids can significantly down regulate △Np73 mRNA and protein expression in MCF- 7 cells,and inhibit cell growth and proliferation,indicating that targeting silence of △Np73 can be a promising strategy for treating breast cancer in the future.