蛋白酶体抑制剂MG132对RhoA诱导的肿瘤血管生成的抑制作用的研究

The Effect of RhoA and Proteasome Inhibitor MG132 on Angiogenesis in Tumors

目的探讨RhoA对血管内皮生长因子(VEGF)、缺氧诱导因子-1α(HIF-1α)和微血管生成的影响以及蛋白酶体抑制剂MG132对RhoA调控作用的影响。方法将组成性激活的RhoA的真核表达质粒,在脂质体介导下转染胃癌细胞系MKN-45,经G418筛选出阳性单克隆并用Western blot检测是否稳定转染成功;应用ELISA检测不同细胞培养上清中VEGF的含量;建立组成性激活RhoA的荷瘤鼠模型,并用MG132治疗并观察治疗效果;用免疫组化染色方法检测RhoA及MG132对肿瘤细胞表达HIF-1α、VEGF及CD31的影响。结果组成性激活RhoA的稳定转染细胞株构建成功;组成性激活的RhoA促进VEGF的分泌,而MG132抑制VEGF的分泌;组成性激活的RhoA促进肿瘤的生长,差异有统计学意义(P<0.05),MG132抑制肿瘤的生长,差异有统计学意义(P<0.01);组成性激活的RhoA促进HIF-1α、VEGF及CD31的表达,MG132抑制HIF-1α、VEGF及CD31的表达,差异均有统计学意义(P<0.05)。结论 MG132通过抑制RhoA对HIF-1α、VEGF及CD31的上调来影响肿瘤血管的生成。

Objective To investigate the effect of RhoA to VEGF,HIF-1α and MVD（microvascular density） and the effect of MG132 to RhoA.Methods The constitutively-active mutant vectors of RhoA（pCEFL-GST-V14RhoA） were transfected into gastric cancer cell line MKN-45 by Lipofectamine 2000,single clones were selected by G418 and identified with western blot.The content of VEGF in the conditioned media was detected by ELISA.Constitutively-active RhoA nude mice models were established and treated with MG132.The effect of RhoA and MG132 on expression of HIF-1α,VEGF and CD31 were detected by immunohistochemistry.Results Cell line of stable-transfected constitutively-active RhoA was established and constitutively-active RhoA could stimulate secretion of VEGF but MG132 inhibited that.Constitutively-active RhoA could obviously induce growth of tumor（P0.05）,but MG132 inhibited it（P0.05）.Constitutively-active RhoA could promote protein of HIF-1α,VEGF and CD31 but MG132 inhibited the function of RhoA（P0.05）.Conclsuion Our studies indicates that MG132 could affect angiogenesis of tumors through inhibition the regulating function of RhoA on HIF-1α,VEGF and CD31.