[Coordination inhibition of the proliferation of MCF-7 by enhancing expression of p53,p21 and decreasing expression of c-myc].

To study the coordination inhibition of the proliferation of breast cancer cell line MCF-7 by enhancing expression of p53,p21 and decreasing expression of c-myc, as well as the relationship among these genes when they express in the cells, eukaryotic expression plasmids of sense p53,p21 and antisense c-myc were constructed first, different concentrations of three plasmids were determined and the combinations were designed according to factorial design. Cells were transfected by the combination plasimids, then the inhibition rate of proliferation of the transfected cells were tested. The results were analyzed using the methods of statistics including Jin's Q-test, Least significant difference (LSD), cluster analysis. It was shown that all of them (Sense p21,p53, antisense c-myc) could inhibit the proliferation of MCF-7 in different levels of concentration, while the degrees of inhibition were different among them. In the aspect of coordination inhibition, the proliferation of MCF-7 was inhibited much strongly by p21 coordination with antisense c-myc and p53 coordination with antisense c-myc, but p53 coordination with p21 did not show inhibition effect. Rusults of cluster analysis showed that the first combination of three genes showed the best coordination, the ninth combination had the highest rate of inhibition. In conclusion, we suppose that when p53 as a cancer suppressor gene and p21 as a CDK suppressor gene express highly, and the expression of c-myc as a cancer gene is inhibited meantime could obviously enhance the inhibition on the proliferation of MCF-7 cells by coordination effect.