EFFECT OF DOWN-REGULATION VEGF-C GENE ON MULTIPLICATION AND APOPTOSIS OF BREAST CANCER CELLS

Objective To investigate the feasibility and specificity of gene therapy for breast cancer by chemically modified siRNA mediated RNA interference using in-vitro RNA(siRNA) inhibited vascular endothelial growth factor-C(VEGF-C) expression.Methods siRNA targeting VEGF-C gene was designed,cationic liposome LipofectamineTM 2000 used as transfecing agent,and ds-siRNA was transfected into MCF-7 cells with lipofectamine.Blank control group(only serum-and antibiotic-free medium was added),liposome control group(only LipofectamineTM 2000),three siRNA-concentration-gradient groups(50,100 and 200 nmol/L) and siRNA SCR group(100 nmol/L) were established.The proliferation of MCF-7 cells was detected by MTT colorimetry,and apoptosis measured by Hoechst 33258 staining.The expressions of mRNA of VEGF-C and p53 gene were detected by both RT-PCR and Western blot before and after transfection.Results The growth of MCF-7 cells was inhibited at 48 h after siRNA transfection,and apoptosis bodies were observed in cells with fluorescent stain by Hoechst 33258.The expressions of VEGF-C and p53 were significantly down-regulated(F=30.74-114.11,q=5.74-20.75,P0.01).No significance of differences was noted among blank control,lipofectamine control and siRNA SCR groups(P0.05) Conclusion The interference of modified siRNA with chemically-mediated RNAi can down regulate VEGF-C gene expression and inhibit cell proliferation of MCF-7.The p53 gene in breast cancer is associated with the expression of VEGF-C,which indicates that mutant p53 is likely involved in the regulation of VEGF-C.