白藜芦醇抑制ls174t细胞生长及其在裸鼠皮下移植瘤中的作用机制

Inhibitory effect of resveratrol on the growth of human colon cancer ls174t cells and its subcutaneously transplanted tumor in nude mice and the mechanism of action

目的探讨白藜芦醇对结肠癌ls174t细胞及其鼠移植瘤组织生长的作用及机制。方法二苯基溴化四氮唑蓝（MTT）法检测白藜芦醇对体外ls174t细胞的抑制作用，透射电镜观察细胞凋亡，流式细胞仪检测细胞凋亡率和细胞周期的改变，逆转录聚合酶链反应（RT-PCR）检测bc1-2和baxmRNA的表达，Western blot法检测bc1-2和bax蛋白的表达。将ls174t细胞移植至裸鼠皮下，观察白藜芦醇对皮下移植瘤生长的影响；RT-PCR法检测瘤组织中bc1-2和bax mRNA的表达，Western blot法检测瘤组织中bc1-2和bax蛋白的表达。结果（1）白藜芦醇具有体外抑制ls174t细胞增殖的作用，25、50、100、200、400μmol／L的白藜芦醇作用ls174t细胞24h，抑制率分别为1.0％、9.1％、17.4％、27.8％和66.5％；作用48h，抑制率分别为3.6％、13.7％、30.2％、58.4％和86.1％；作用72h，抑制率分别为18.1％、33.0％、48.6％、61.2％和89.4％，差异有统计学意义（P〈0.01）。不同浓度的白藜芦醇作用ls174t细胞后，随白藜芦醇浓度的增加，bc1-2 mRNA和蛋白表达降低，bax mRNA和蛋白表达增强。流式细胞仪检测显示，白藜芦醇能诱导ls174t细胞的凋亡，使细胞周期阻滞于s期。（2）白藜芦醇可抑制裸鼠皮下移植瘤的生长，最大抑制率为47.9％。200mg／kg白藜芦醇治疗组和800mg／kg白藜芦醇治疗组的裸鼠皮下移植瘤重量分别为（4.10±0.18）g和（3.05±0.35）g，与对照组比较，差异有统计学意义（P〈0.01）。白藜芦醇可使裸鼠肿瘤组织中bcl-2mRNA和蛋白表达降低，而bax mRNA和蛋白表达增强。结论白藜芦醇具有抑制ls174T细胞和皮下移植瘤生长的作用，其机制可能与诱发细胞凋亡和调节be1-2、bax表达有关。

Objective To explore the effect and mechanism of resveratrol against human colon cancer ls174t cells in vitro and the growth of colon cancer in tumor-bearing nude mice. Methods MTT method was used to test the inhibiting effect of resveratrol on the growth and proliferation of ls174t cells. Transmission electron microscopy was used to observe the morphological changes of cell apoptosis, and FCM assay was performed to measure the changes of cell apoptosis rate and cell cycle. RT-PCR method was used to detect the expression of bcl-2 and hax mRNA, and Western blot was used to detect the expression of bcl- 2 and bax protein. Results MTT test revealed that resveratrol showed significant inhibiting effect on lsl74t cells in a concentration-and time-dependent manner. In the concentration range of 25, 50, 100, 200 and 400μmol/L, the inhibition rate after resveratrol treatment for 24 hours was respectively 1.0% , 9.1% , 17.4% , 27.8% and 66.5% , while the inhibition rate after treatment for 48 hours was respectively 3.6% , 13.7% , 30.2% , 58.4% and 86. I% , and the inhibition rate after treatment for 72 hours was 18.1% , 33.0%, 48.6%, 61.2% and 89.4%, respectively, showing a very significant difference （ P 〈 0.01 ）. Typical ultrastructural apoptotic changes were observed in resveratrol-treated ls174t ceils. It was found through FCM assay that resveratrol caused apoptosis in ls174 cells and blocked the cell cycle at S phase. RT- PCR and Western blot test showed that after the treatment of colon cancer cells with resveratrol at different concentrations （25, 50, 100 and 200μmol/L）, the expression level of bcl-2 was decreased, while expression level of bax was increased. The highest inhibition rate was 47.9%. In 200 mg/kg and 800 mg/kg resveratrol treatment groups, the weight of subcutaneously transplanted tumors in nude mice was 4.10±0.18 g and 3.05±0.35 g, respectively, the difference was significant compared with that of the control group （P 〈0.01）. Conclusion Resveratrol can inhibit the growth of ls174t cells through apoptosis induction. The mechanism is probably related to inhibition of anti-apoptotic factor bcl-2 and enhancement of expression of apoptotic factor bax.