辛伐他汀抑制过表达HER2型结直肠癌的肿瘤血管生成

Simvastatin inhibits the tumor angiogenesis in HER2-overexpressing human colorectal cancer

目的探讨辛伐他汀在结直肠癌(CRC)血管生成调控中的作用及分子机制。方法 Western blot法检测HER2和VEGF蛋白表达。采用Matrigel小管形成、MTT、伤口愈合试验和Transwell检测辛伐他汀对CRC小管形成、增殖、迁移和侵袭能力的影响。另外,采用HTC-116和LoVo细胞构建裸鼠移植瘤模型,模型小鼠分成2组,对照组每日注射0.1 ml磷酸盐缓冲盐水,治疗组小鼠每天注射50 mg/kg辛伐他汀。免疫组化方法检测肿瘤CD31表达情况,计算肿瘤微血管密度(MVD)。观察辛伐他汀对裸鼠肿瘤生长及肿瘤血管形成的影响。结果 VEGF和HER2在CRC细胞中表达上调,而辛伐他汀明显降低其表达。辛伐他汀预处理可减少体外内皮细胞小管形成和体内微血管密度。辛伐他汀明显抑制HRG-β1诱导的血管形成。机制研究显示,辛伐他汀通过抑制VEGF分泌而显著抑制HER2诱导引起的肿瘤血管生成。结论辛伐他汀通过对HER2/VEGF轴的调控抑制肿瘤血管生成,为辛伐他汀抑制过表达HER2型CRC提供了一种新的机制。

Objective To investigate the antiangiogenic effect of simvastatin on colorectal cancer(CRC)and the mechanism of its antiangiogenic effect.Methods Western blot was used to detect the protein expression of HER2 and VEGF.The effects of simvastatin on tubule formation,proliferation,migration and invasion of CRC were examined by Matrigel tubule formation,MTT,wound healing and Transwell assays.In addition,the xenograft tumor model of nude mice was constructed by injection with HTC-116 and LoVo cells.The model mice were divided into 2 groups,negative control group(injected with 0.1 ml of phosphate buffer saline daily)and simvastatin treatment group[injected simvastatin with 50 mg/(kg·d)].The microvessel density was analyzed via examining the expression of CD31 in tumor tissues by immunohistochemistry.The effect of simvastatin on tumor growth and angiogenesis in nude mice was observed.Results Colorectal cancer cells bad high expression levels of VEGF and HER2,which could be apparently reduced by simvastatin.Simvastatin pretreatment decreased endothelial tube formation in vitro and microvessel density in vivo.Moreover,simvastatin markedly inhibited tumor angiogenesis even in the presence of heregulin(HRG)-β1 pre-treatment in tumor cells.Mechanistic investigation showed that simvastatin inhibited HER2-induced tumor angiogenesis by suppressing VEGF secretion.Conclusion Simvastatin inhibits tumor angiogenesis by regulating the HER2/VEGF axis,which provides a new mechanism for simvastatin to inhibit the overexpression of HER2 CRC.