3-溴丙酮酸对人胃癌细胞裸小鼠皮下种植瘤的作用机制

Molecular studies of growth inhibition by 3-bromopyruvic acid in human gastric tumors implanted in nude mice

目的探讨3-溴丙酮酸(3-Bromopyruvic acid,3-BrPA)对人胃癌细胞株SGC-7901裸鼠皮下种植瘤的抑制作用及其机制。方法建立人胃癌裸鼠皮下种植瘤模型,将成瘤后的裸鼠随机分为实验组:3-BrPA低剂量、3-BrPA中剂量、3-BrPA高剂量组;PBS(磷酸盐缓冲液)阴性对照组1(pH7.4),PBS阴性对照组2(pH6.8～7.8);阳性对照5-FU组。每天于瘤体周围皮下注射给药,连续4周,停药24h后取出瘤体并检测瘤体细胞中己糖激酶的活性,分别用免疫组化SP法和Western blot法检测cleaved caspase-3、bax、bcl-2和p53蛋白的表达。结果随着3-BrPA剂量的增加,瘤体细胞中己糖激酶的活性逐渐下降,并呈剂量依赖性。3-BrPA给药组的p53、bcl-2蛋白表达下降,而bax、caspase-3(P17KD)蛋白表达升高,与PBS阴性对照组相比差异均有统计学意义(P<0.05)。结论 3-BrPA诱导人胃癌细胞株SGC-7901裸鼠皮下种植瘤细胞凋亡的机制可能是通过抑制细胞内的己糖激酶活性,上调bax蛋白的表达,下调p53、bcl-2蛋白的表达,最终活化caspase-3而引起的。

Objective To investigate the effects of 3-Bromopyruvic acid（3JBrPA ） on the growth of gastric cancer in vivo and to explore how it exerts these effects. Methods Human gastric carcinoma SGC-7901 ceils were subcutaneously implanted in nude mice,which were randomly divided into six groups （each n=lO） that received subcutaneous injections of 1.85,2.23,or 2.67 mg/kg 3-BrPA;5-FU; or PBS （two groups ）.After 28 days of treatment,the expression of apoptosis-associated proteins p53,bcl-2,bax and active easpase-3 was examined by immunohistochemistry and Western blotting.Hexokinase activity was assessed using a commercial kit. Results Hexokinase activity gradually declined with increasing 3-BrPA dose. Mice in the 3-BrPA groups showed lower expression of p53 and bcl-2 and higher expression of bax and active caspase-3 than did mice in the PBS groups（P〈0.05）. Conclusion 3-BrPA can induce apoptosis of human gastric cancer cells, and it appears to do so by altering expression of apoptosis-associated proteins and inhibiting hexokinase activity.