Inhibition of expression of VEGF gene by siRNA influences cell cycle in breast cancer cells

Objective:To evaluate the influence on MCF-7 cells cell cycle by small interference RNA targeting c-myc gene.Methods:Small interfering RNA(siRNA) targeting c-myc gene was designed and DNA template was synthesized,then siRNA was obtained by in vitro transcription.After ds-siRNA was transfected into MCF-7 cells with LipofectamineTM,the proliferation of MCF-7 cells was detected by cell counting.Flow cytometry method was used to detect the change of cycling of cell level.The effect of siRNA on p21 and Cyclin D1 mRNA level was detected by reverse transcription-polymerse chain reaction(RT-PCR).The effect of siRNA on phosphorylated ERK was tested by Westernblot.Blank control group and siRNAscr group were taken as controls.Results:The siRNA targeting human VEGF effectively inhibited the proliferation of MCF-7 cells,and changed cell cycle after transfected;siRNA induced an increase of G0/G1 phase cells and a significant decreaseof S phase cells.The expression of p21 was up-regulated at mRNA level,the expression of Cyclin D1 was down-regulated at mRNA level,and phosphorylated ERK was down-regulated at protein level.But the control scramble siRNA showed no effects.Conclusions:The siRNA targeting human VEGF gene could induce G0/G1 arrest and inhibit cell proliferation in MCF-7 cells by up-regulating the expression of p21and down-regulated the expression of CyclinD1 and phosphorylated ERK.