摘要
Objective To investigate the mechanism of all-trans retinoic acid (ATRA) on the regulation of the cell cycle in gastric cancer cells. Methods The protein level was detected by Western blot. Immunoprecipitation was used in protein kinase activity determination. Cell growth and cell cycle phase were examined by MTT assay and flow-cytometric analysis, respectively.Results ATRA could effectively induce G0/G1 arrest and inhibit cell growth in certain human gastric cancer cell lines. ATRA might induce p21WAF1/CIP1 expression in ATRA-sensitive cell lines through p53-dependent and p53-independent pathways. Induction of p21WAF1/CIP1 caused decrease in CDK4 and CDK2 activities independent of CDK4 and CDK2 protein expression levels. In addition, the dephosphorylated form of Rb protein increased because of the down-regulation of CDK4 and CDK2 activities by ATRA. Conclusions Growth inhibition on gastric cancer cells by ATRA occurs through the regulation of relevant proteins leading to the arrest of cell cycle progression.
目的 探讨ATRA调节胃癌细胞生长的作用机理。方法 Westernblot测定蛋白表达水平 ,免疫沉淀测定蛋白激酶活性 ,MTT方法检测细胞生长和流式细胞术分析细胞周期。结果 ATRA有效地诱导细胞滞留G0 /G1期并抑制胃癌细胞生长。ATRA通过依赖P5 3和非依赖P5 3途径诱导ATRA敏感细胞的P2 1WAF1/CIP1表达 ,由此导致CDK4 和CDK2 活性下降 ,但对CDK4 和CDK2 蛋白表达没有影响。另外 ,由于ATRA抑制CDK4 和CDK2 活性 ,导致Rb蛋白去磷酸化水平上升。结论 ATRA通过调节细胞周期进程的相关蛋白而抑制胃癌细胞生长。
基金
ThisworkwassupportedbytheNationalOutstandingYouthScienceFoundationofChina (Btype
No 3982 5 5 0 2 )
theNationalNaturalScienceFoundationofChina (No .39880 0 15 )