BSO对人胃腺癌SGC7901细胞化疗敏感性的影响

Effects of BSO on chemosensitivity of gastric carcinoma cell

目的研究2-氨基4-(S-丁基磺酰亚氨)丁酸(BSO)对人胃腺癌SGC7901细胞化疗敏感性的影响。方法采用四甲基偶氮唑盐微量酶反应比色法(MTT)测定BSO对人胃腺癌SGC7901细胞的半数抑制浓度(IC50),进而利用无毒浓度的BSO和乙酰半胱氨酸(NAC)预处理细胞后,检测细胞对依托泊苷(VP-16)和多柔比星(ADM)化疗敏感性的变化,同时,采用试剂盒检测肿瘤细胞内谷胱甘肽(GSH)含量,γ-谷氨酸-半胱氨酸合成酶(γ-GCS)试剂盒测定γ-GCS活性,并以2',7'-二氯荧光黄双乙酸盐(DCHF-DA)测定不同处理条件下细胞内活性氧(ROS)水平的改变。结果 MTT实验显示,BSO对SGC7901细胞的IC50为3.5 mg/ml。根据药物无毒浓度选择原则,选取20%IC50BSO浓度(0.7 mg/ml)进行后续实验。结果显示,BSO通过抑制人胃腺癌SGC7901细胞内γ-GCS酶活性来减少GSH合成(P<0.05),促使细胞内ROS水平升高(P<0.01),加入NAC后可部分逆转BSO对GSH合成的抑制作用(P<0.05)。BSO与ADM和VP-16联合作用后,使得二者的IC50值分别下降55.9%和71%。结论 BSO通过抑制γ-GCS的活性,降低细胞内GSH的含量,提高ROS水平,增强细胞化疗敏感性。

Objective To study the influence of DL-buthionine（S,R）-sulfoximin（BSO） on chemosensitivity of gastric carcinoma cell.Methods The 50% inhibitory concentration（IC50）of BSO on SGC7901 cell was measured by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazo-lium bromide（MTT） in order to select the experimental concentration.SGC7901 cells were pretreated by BSO and nacetylcysteine（NAC） at the concentration without obviously influencing the viability of cells,followed by detecting the alteration of chemosensitivity of the cells to VP-16 and ADM.GSH detecting kit and γ-glutamylcysteinesynthetase（γ-GCS） detecting kit were then utilized to assay the contents of intracellular glutathione（GSH） and the activity of γ-GCS respectively.Meanwhile,the change of cellu-lar reactive oxygen species（ROS） level,under different treatment,was observed by 2′,7′-dichlorofluorescin diace-tate（DCFH-DA） probe.ResultsThe result of MTT experiment showed that the IC50 of BSO on SGC7901 cell was 3.5 mg/ml.According to the principle of the selection of non-toxic concentration,20% IC50 of BSO（0.7 mg/ml） was used in the subsequent tests.Results showed that the activity of γ-GCS was significantly inhibited by BSO（P0.05）,synthesis of GSH were reduced（P0.01） and the concentration of ROS was increased（P0.01）.But NAC could reverse partially the inhibition of BSO to the synthesis of GSH（P0.05）.After the treatment of BSO combined with ADM and VP-16,their IC50% values were decreased by 55.9% and 71%,respectively.Conclusion BSO can downregulate the levels of GSH and upregulate the concentrations of ROS via the inhibition of γ-GCS enzyme to enhance gastric cancer cells chemosensitivity.