| Objective To investigate the effect of tansfected p21WAF1/CIP1- p27KIP1(p21-p27) genes on the cell cycle of human gastric carcinoma cell line (SGC-7901). Methods Recombinant eukaryotic expression vector pIRES- p21- p27 containing exogenous human p21 cDNA and p27 cDNA was constructed and transfected into human gastric cell line SGC-7901 by the method of lipofection. Collect and fix the cells of 12h, 24h, 48h, 72h and 5d with 4℃precooling alcohol respectively and then detect the change of cell cycle and the expression of cyclin D1 and cyclin E in different phase of cell cycle with flow cytometry (FCM). There were five groups in the experiment: SGC-7901 group, plRES-SGC-7901 group, plRES- p21- p27-SGC-7901 group, DADS-SGC-7901 group, and plRES- p21- p27+ DADS group. The SGC-7901 group was a negative control group without any intervention; the plRES-SGC-7901 group was transfected with only the plRES; the plRES- p21-p27-SGC-7901 group was transfected with the expression vector pIRES- p21- p27; the DADS-SGC-7901 group was treated with diallyl disulfide (DADS), a drug inducing the differentiation of carcinoma cells which was being studied by more and more people; the plRES- p21- p27+DADS group was transfected with the expression vector plRES- p21- p27 first and then was treated with DADS to induce the gastric carcinoma cells to differentiate furtherly. There were three indications to observate: the disposition of cell cycle; the expression of cyclin D1 and cyclin E in different phase of cell cycle. All the data was analyzed with statistical package of SPSS11.5 for windows. Results The proliferation of SGC-7901 was significantly inhibited in all the three grups: pIRES- p21- p27-SGC-7901 group, DADS-SGC-7901 group and plRES- p21- p27+DADS group, whereas pIRESp21-p27-SGC-7901 group was inhibited in G1 phase; DADS-SGC-7901 group was inhibited in G2/M phase; plRES- p21- p27+DADS group was inhibited not only in G1 phase but also in G2/M phase. The cell percentage of S phase was decreased strikingly in plRES- p21-p27+DADS group, compared to plRES- p21- p27-SGC-790 and DADS-SGC-7901 group, the difference was very significant. As a result, the expression of cyclin D1 and cylicn E found in the three groups was decreased dramatically, a notable difference was found also compared to the control group. However, there was no significant difference in the three groups, compared to each other. Conclusions The proliferation of SGC-7901 transfected with the genes p21- p27 was significantly inhibited in G1 phase. The same result was found in SGC- 7901 treated by DADS; however cells were resisted in G2/M phase rather than G1 phase. The proliferation of cells would be inhibited more remarkablely if the SGC-7901 transfected with the genes p21- p27 was induced to differentiate furtherly with DADS. The cells were resisted not only in G2/M phase but also in G1 phase, which decreased the cells in S phase strikingly. The application of transfection with the genes p21 -p27 accompanied with DADS is hoped to be a new method to cure gastric carcinoma, which has a bright future. |
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