干扰血管内皮生长因子表达联合γ射线对食管癌细胞移植瘤的影响

Effect of γ-rays combined with blocking VEGF expression on esophageal cancer xenografts

目的 研究反义cDNA干扰血管内皮生长因子（VEGF）表达联合γ射线对裸鼠移植瘤的影响,并观察各组裸鼠肿瘤病理组织学和细胞生物学特征的变化,为VEGF基因治疗联合放射治疗食管癌提供理论依据.方法 将32只Balb/c/nu裸鼠随机分为4组：对照组、单纯照射组、反义组和反义＋照射组,使用已转染和未转染反义VEGFcDNA TE-1食管癌细胞株,分别建立裸鼠爪垫移植瘤模型,瘤体直径0.8～1.0 cm,60Co γ射线18 Gy单次照射单纯照射组与反义＋照射组裸鼠移植瘤,对比观察各组移植瘤生长情况,检测移植瘤组织中VEGF mRNA和蛋白的表达,并分析肿瘤组织中细胞凋亡情况.结果 与未转染两组比较,转染两组瘤体生长速度慢,成瘤潜伏期延长（t=13.898,P＜0.01）.反义组肿瘤体积为（1207.50±97.07）mm3,反义＋照射组为（1057.5±91.50）mm3,两者差异无统计学意义（t=1.124,P＞0.05）,而此2组与对照组（5442.50±185.08）mm3和单纯照射组（2922.50±152.773）mm3体积间差异有统计学意义（t=9.475～21.238,P＜0.01）.反义组与反义＋照射组VEGF mRNA和蛋白表达较对照组和单纯照射组差异有统计学意义（F=387.394、13.519,P＜0.01）.结论 抗VEGF治疗可有效地抑制裸鼠移植瘤的生长,但单纯抑制VEGF表达对增加裸鼠移植瘤放射治疗增敏效果有限,需进一步研究.

Objective To investigate the effect of blocking VEGF expression on the radiation sensitivity of esophageal cancer cell line TE-1 in vivo. Methods 32 male Balb/c/nu nude mice were randomly divided into four groups, including control group, radiation group, anti-VEGF group, and anti-VEGF ＋ radiation group. The anti-VEGFcDNA cells were subcutaneously injected into the paw pats of mice （2 × 106/100 μl）. The subcutaneous tumors were irradiated with 18 Gy of 60Co y-rays when the diameter of tumors varied from 0. 8 to 1.0 cm. The volume of the tumors was measured before and after irradiation, respectively. The expression level of VEGF mRNA and protein were examined by RT-PCR and Western blotting, respectively. Apoptotic cells were detected by electron micrographs. Results Latent period of the tumor formation of anti-VEGF group was lengthened compared with other groups（t = 13. 898,P ＜0.01 ）. The volumes of tumor in anti-VEGF group [ （ 1207. 50 ± 97.07 ） mm3 ] and anti-VEGF ＋radiation group [ （ 1057. 5 ± 91.50 ） mm3 ] were not statistically different post-irradiation （ t = 1. 124, P ＞0.05 ） , but smaller than those in control group [ （ 5442. 50 ± 185.08 ） mm3 ] and radiation group [ （2922. 50 ± 152. 773）mm3 ] with statistical differences（ t = 9. 475-21. 238, P ＜ 0. 01 ）. The expression level of endogenous VEGFmRNA and protein in anti-VEGF group and anti-VEGF ＋ radiation group were statistically different from control group and radiation group （F = 387.394, 13.519, P ＜ 0.01 ）.Conclusions Antisense VEGF could inhibit the proliferation of esophageal cancer cell in the nude mice.Effect of blocking VEGF expression before irradiation on esophageal cancer xenografts might be limited.