抗血管内皮生长因子单克隆抗体bevacizumab对实验性脉络膜黑色素瘤生长的影响

The influence of bevacizumab on human choroidal melanoma in vivo

目的 观察并探讨抗血管内皮生长因子（VEGF）单克隆抗体bevacizumab对人眼脉络膜黑色素瘤（CM）细胞系OCM-1细胞裸鼠移植瘤生长的影响及其机制.方法 OCM-1细胞植入18只雌性裸鼠腋周皮下,建立移植肿瘤模型后随机分成空白对照组（A组）、阴性对照组（B组）、注药治疗组（C组）.A组未作处理;B组腹腔注射生理盐水0.2 ml;C组以5 mg/kg剂量腹腔注射生理盐水稀释的bevacizumab溶液0.2 ml.连续用药14 d,期间观察肿瘤生长情况.14 d后处死裸鼠,称量肿瘤重量并计算抑瘤率;免疫组织化学染色检测各组肿瘤组织增生细胞相关核抗原（ki67）、凋亡抑制因子（survivin）表达情况;逆转录聚合酶链反应（RT-PCR）分析各组VEGF和survivin mRNA水平的表达.结果 C组肿瘤体积、重量分别为（598.86±321.81）mm3、（0.66±0.15）g,A、B组肿瘤体积、重量分别为（1 715.15±278.16）mm3、（1.54±0.39）g和（1 750.23±206.36）mm3、（1.54±0.31）g,C组与A、B组肿瘤体积、重量比较,差异均有统计学意义（F=34.53,8.69;P=0.00,0.01）;C组抑瘤率为57.14%,A、B组抑瘤率分别为5.31%、6.25%.A、B、C组,ki67增生指数分别为（51.85±1.32）%、（46.30±1.39）%、（27.90±0.90）%,C组与A、B组比较,ki67增生指数差异有统计学意义（H=15.17,P=0.00）.C组survivin mRNA表达为0.49±0.02,A、B组survivin mRNA表达分别为（0.82±0.05）、（0.61±0.05）,C组与A、B组比较,survivin mRNA表达差异有统计学意义（F=15.17,P＜0.05）.C组VEGF mRNA表达为（0.32±0.08）,A、B组VEGF mRNA表达分别为（0.73±0.07）、（0.80±0.04）,C组与A、B组比较,VEGF mRNA表达差异有统计学意义（F=12.05,P＜0.05）.结论 Bevacizumab能够抑制OCM-1裸鼠移植瘤的生长,其机制可能与抑制VEGF活性,下调survivin表达,抑制细胞增生有关.

Objective To investigate the influence of vascular endothelial growth factor （VEGF）antagonist bevacizumab on the growth of human choroidal melanoma （CM） OCM-1 cell xenografts in nude mice, and to explore the probable mechanism. Methods OCM-1 cells were subcutaneously implanted on 18 nude mice to establish ectopic model of human CM. The nude mice with the tumor of 5 mm in diameter were randomly divided into three groups： untreated group （group A）, normal saline （NS） group （group B）, drug treated group （group C）. Bevacizumab was intraperitoneally injected for 14 consecutive days in group C, and the same volume of NS was used at a same way in group B. The volume and weight of implanted tumor as well as inhibitory rates of drug on tumor were calculated, ki67 and survivin proteins were measured with immunohistochemistry, and the mRNA expression of VEGF and survivin were assessed by RT-PCR. Results The volume and weight of tumor was （598.86±321.81） mm3 , （0. 66±0. 15） g;（1 715. 15±278. 16）mm3 , （1.54±0. 39） g and （1 750. 23±206.36） mm3 , （1. 54±0. 31） g in groups C, A and B, respectively.There were significant differences between group C and A （F=34.53, P=0. 00） and group C and group B（F= 8.69, P=0.01）. The inhibitory rate of these three groups were 57. 14%, 5. 31%, 6. 25%,respectively, and the proliferation index （PI） of ki67 in these three groups were （51.85±1.32）%, （46. 30±1.39） %, （27. 90±0. 90）%, respectively, there were significant differences in ki67 PI between C group and A or B group （ H = 15.17, P = 0.00）. The expression of survivin mRNA was （0.49 ± 0.02 ）, （0. 82 ± 0. 05）and （0. 61±0.05） in groupss C, A and B, respectively, there were significant differences between C group and A or B group （F=15.17, P〈0. 05） . The expression of VEGF mRNA was （0. 32±0. 08）, （0. 73±0. 07）, （0. 80±0.04） in groups C, A and B, significant difference was found between group C and A or B group （F= 12.05,P〈0. 05）. Conclusion Bevacizumab can inhibit the growth of human CM in nude mice probably by inhibiting the activity of VEGF and downregulating survivin expression of the tumor as well as inhibiting the growth of the tumor.