内皮抑素对人肝癌细胞HepG2 VEGF表达的影响及对血管生成的抑制作用

目的探讨内皮抑素(Endostatin)对体外条件下肝癌细胞HepG2血管内皮生长因子(vascular endothelialgrowth factor,VEGF)表达的影响以及体内条件抑制血管生成的作用。方法采用不同浓度的重组人血管内皮抑制素恩度(Endostar,YH-16)体外作用于肝癌细胞株HepG2,采用RT-PCR和Western blot法检测其VEGF的表达水平。并将肿瘤细胞接种于裸鼠背部皮下,形成裸鼠移植瘤模型,采用瘤周皮下注射的办法将不同浓度的恩度作用于瘤体,通过免疫组化以及超声探测仪检测,观察其对移植瘤生长以及微血管密度的影响。结果 RT-PCR和Western blot结果显示,恩度能在体外抑制肝癌细胞VEGF的表达,且其表达随恩度浓度的增加而呈"V"字型变化,当恩度浓度为25μg/mL时,对肝癌细胞VEGF表达的抑制作用最为明显(P<0.05)。不同浓度的恩度作用于裸鼠移植瘤14d后,瘤体的生长速度均较阴性对照组减慢,且部分瘤体发生退缩(P<0.05),25mg/kg组瘤体的抑制最为明显,瘤体体积为注射前的81.98%;免疫组织化学检测结果提示恩度在体内条件下能抑制移植瘤内肿瘤细胞VEGF的表达,其中25mg/kg组阳性细胞数<30%为阴性(-),并且恩度能抑制瘤体内微血管的生成。结论恩度可以在体外抑制肝癌细胞株HepG2的VEGF表达,且可有效抑制裸鼠移植瘤内新生血管的生长。

Antitumor and Antiangiogenic Effect of Endostatin on HepG2 Cells in vivo and in vitro

Objective To explore the effect of recombinant human endostatin(Endostar,YH-16)on the expression of vascular endothelial growth factor(VEGF)in HepG2 cells in vitro and the angiogenesis of hepatocellular carcinoma xenograft on nude mice in vivo.Methods RT-PCR and Western blot were employed to detect the expression of VEGF in the HepG2 cells treated with different doses of endostar in vitro.HepG2 cells were inoculated into the nude mice,and different doses of endostar were injected surrounding the transplanted tumor.The inhibitory effects of endostar on the growth of xenograft were assessed by growth curve which guided by B-ultrasound,and the expression of VEGF and the microvessel density in the xenograft after treatment by different doses of endostar were detected by using immunohistochemistry.Results RT-PCR and Western blot confirmed that endostar efficiently inhibited the expression of VEGF in vitro,and when the dose was as high as 25 μg/mL,the inhibition of VEGF reached its peak.Moreover,as compared with the control group,the tumor weight and volume in the groups which treated by different doses of endostar were significantly reduced(P<0.05).Meanwhile the result of immunohistochemistry revealed that the expression of VEGF and the microvessel density in the xenograft were decreased as the dose of endostar was increased.When the dose was as high as 25 mg/kg,the number of the cells positive for VEGF was less than 30%(-),and the number of microvessels was significantly lower than in control group.Conclusion Endostar can effectively inhibit the expression of VEGF in HepG2 cells in vitro and the angiogenesis of HepG2 cell xenograf in nude mice in vivo.