Rho GTP酶在ω-3多不饱和脂肪酸抑制人前列腺癌PC-3细胞转移中的作用

背景与目的:近年来,多不饱和脂肪酸对肿瘤发生、发展影响的研究备受关注.本实验主要观察两种ω-3多不饱和脂肪酸(ω-3 polyunsaturated fatty acid,ω-3 PUFA)二十碳五烯酸(eicosapentaenoic acid,EPA)和二十二碳六烯酸(docosahexaenoic acid,DHA)对人前列腺癌细胞株PC-3转移的影响,并通过检测ω-3 PUFA对细胞内Rho GTP酶蛋白表达及细胞骨架重组影响,揭示Rho GTP酶在ω-3 PUFA抑制肿瘤转移中的作用.方法:MTT法观察ω-3 PUFA对PC-3细胞增殖能力的影响,体外粘附实验、侵袭实验和迁移实验观察ω-3 PUFA对肿瘤细胞转移的影响.Western blot法检测ω-3 PUFA对与细胞骨架重组相关的RhoA、Rac1、Rac2和Cdc42蛋白表达的影响.免疫荧光细胞化学法标记微丝和微管,激光共聚焦扫描显微镜观察ω-3 PUFA对细胞骨架重组的影响.结果:EPA及DHA均能抑制PC-3细胞增殖,增殖抑制率均随处理浓度增大和作用时间延长而增加.与对照组比较,60μmol/L的EPA或DHA处理后的PC-3细胞体外粘附性、侵袭性和迁移性均显著下降(P＜0.05).ω-3 PUFA能显著下调Rac1、Rac2和Cdc42蛋白表达(P＜0.05),并能明显影响细胞内微丝和微管细胞骨架的结构和分布.结论:ω-3 PUFA能够通过下调Rho GTP酶基因表达,抑制Rho GTP酶对细胞骨架重组的调控,导致细胞骨架结构改变,削弱肿瘤细胞的粘附性、侵袭性和迁移性,抑制PC-3细胞的转移.

Role of Rho GTPase in inhibiting metastatic ability of human prostate cancer cell line PC-3 by omega-3 polyunsaturated fatty acid

BACKGROUND & OBJECTIVE: Recently, researches refer to the influence of polyunsaturated fatty acid (PUFA) on cancer initiation and progression had been highly concerned. This study was to investigate the effects of 2 kinds of omega-3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on the metastatic ability of human prostate cancer cell line PC-3, and explore the role of Rho GTPase in inhibiting cancer metastasis by omega-3 PUFA. METHODS: MTT assay was used to determine the effects of omega-3 PUFA on the proliferation of PC-3 cells. Adhesion assay, invasion assay, and migration assay were used to observe the effects of omega-3 PUFA on the metastatic ability of PC-3 cells. Western blot was used to observe the effects of omega-3 PUFA on the expression of RhoA, Rac1, Rac2, and Cdc42 proteins in PC-3 cells. Laser confocal microscopy was used to investigate the effect of omega-3 PUFA on the reorganization of the microfilaments and microtubules marked by immunofluorescent cytochemistry technology. RESULTS: Both EPA and DHA inhibited the proliferation of PC-3 cells, and the proliferation inhibition rate increased along with the increase of the concentration and treatment time. When treated with 60 mumol/L EPA or DHA for 48 h, the abilities of adhesion, invasion and migration of PC-3 cells were inhibited (P<0.05). omega-3 PUFA significantly suppressed the expression of Rac1, Rac2 and Cdc42 proteins (P<0.05), influenced the distribution and structure of sytoskeletons. CONCLUSION: omega-3 PUFA could inhibit the metastatic ability of PC-3 cells through down-regulating the expression of Rho GTPase and inhibiting the cytoskeleton reorganization.