冬凌草中新二萜化合物Jaridonin激活共济失调毛细血管扩张突变蛋白激酶诱导胃癌细胞周期阻滞

Jaridonin, a new diterpenoid from Isodon rubescens, induces cell cycle arrest in gastric cancer cells through activating ataxia telangiectasia mutated kinase

目的：探讨冬凌草中新型二萜化合物Jaridonin对人胃癌细胞周期的影响及其分子机制。方法采用流式细胞术检测Jaridonin对MGC-803细胞共济失调毛细血管扩张突变（ ATM）蛋白的表达和细胞周期的影响，采用Western blot法检测细胞周期调控相关蛋白的表达情况。结果 Jaridonin对胃癌MGC-803细胞细胞周期具有阻滞作用，10、20μmol／L Jaridonin作用MGC-803细胞6 h，G2／M期细胞比例分别为（18．2±2．5）％和（27．3±3．2）％，与对照组[（10．8±2．2）％]比较，差异有统计学意义（P＜0．05）；作用12 h后，G2／M期细胞比例分别为（24．1±2．0）％和（39．7±5．2）％，与对照组[（12．0±1．5）％]比较，差异有统计学意义（P＜0．01）。 Jaridonin将MGC-803细胞阻滞在G2／M期，且呈浓度和时间依赖性。 Jaridonin作用MGC-803细胞后，ATM、Chk1和Chk2以及磷酸化的Cdc2和CDK2蛋白的表达上调，而非磷酸化的Cdc2和CDK2水平则下降。 ATM抑制剂KU-55933逆转了Jaridonin诱导相关蛋白的表达和G2／M期阻滞。结论 Jaridonin可显著诱导胃癌细胞G2／M期阻滞，其机制与ATM介导的Chk1和Chk2活化，以及Cdc2和CDK2磷酸化失活有关。

Objective To study the effects of Jaridonin, a novel diterpenoid from isodon rubescens, on the cell cycle of human gastric cancer cells and its molecular mechanism of action. Methods Flow cytometry was used to analyze the cell cycle distribution and expression of ataxia telangiectasia mutated kinase （ ATM） after Jaridonin treatment. Western blot was performed to detect the expression of cell cycle-related proteins. Results The results of flow cytometry showed that the percentages of MGC-803 cells in G2/M phase at 6 hours after 0, 10, 20 μmol/L Jaridonin-treatment were （10.8±2.2）%, （18.2±2.5）%, （27.3±3.2）%, respectively;those at 12 hours after Jaridonin-treatment were （12.0±1.5）%, （24.1±2.0）%and （39.7±5.2）%, respectively, indicating a G2/M phase arrest of MGC-803 cells was resulted in a time-and dose-dependent manner. The expressions of ATM, Chk1, Chk2, phosphorylated Cdc2 and CDK2 were up-regulated in the MGC-803 cells after Jaridonin treatment, while the levels of Cdc2 and CDK2 were decreased. KU-55933, an inhibitor of ATM, reversed the expression of relevant proteins and G2/M phase＆amp;nbsp;arrest induced by Jaridonin. Conclusions Jaridonin can significantly induce G2/M arrest in gastric cancer MGC-803 cells. Its mechanism may be related to the activation of ATM and Chk1/2, and inactivation of Cdc2 and CDK2 phosphorylation.