Noxa Gene Inhibited Proliferation and Induced Apoptosis in Human Breast Cancer Cell Line MCF-7

Objective To explore the effect of Noxa gene on proliferation and apoptosis of human breast cancer cell line MCF-7. Methods The recombinant eukaryotic expression plasmid pIRES2-EGFP-Noxa was transiently transfected into human breast cancer cell line MCF-7 with lipofectamine. Both Noxa mRNA and protein were detected by RT-PCR and Western blot respectively. The inhibition of cell proliferation was evaluated by MTT assay. Changes in cell cycle were detected by flow cytometry(FCM).The cell apoptosis was studied by Hoechst 33342 staining. Results Exotic Noxa gene was expressed successfully in MCF-7 cells after transfected. The expression of Noxa mRNA and protein of MCF-7 cells was significantly increasing up-regulated after transfected 24h, 48h and 72h(0.347±0.031,0.703±0.041 and 1.044±0.033 for mRNA and 0.886±0.063,1.013±0.088 and 1.171±0.086 for protein,P<0.05). The Noxa expression inhibited MCF-7 cells proliferation with a time-dependent inhibition rate of (23.9%±4.2%),(36.6%±3.0%) and (47.0%±3.3%) for 24h, 48h and 72h, respectively. In Noxa overexpressed in MCF-7 cells the DNA synthesis was inhibited and arrested in G0/G1 phrase according to FCM. The percent of G0/G1 after transfected 24h、48h and 72h was (68.1%±2.5%),(72.6%±1.5%) and (75.6%±0.9%), respectively,and apoptosis rate was (11.5%±0.9%), (19.6%±0.8%), (25.4%±0.7%),respectively. It was significantly different compared with the control group(P<0.05). Apoptosis rate after transfected 24h, 48h and 72h was (7.3%±4.1%), (16.8%±3.3%) and (23.8%±2.3%), respectively.There were significant difference between Noxa and the control group(P<0.05). Conclusion Noxa gene overexpressed was able to effectively inhibit the proliferation and promote the apoptosis of breast cancer cells.