摘要目的 实时测定贝伐单抗和放射线作用人肺腺癌细胞系(NCI-H141)裸鼠移植瘤后活体乏氧调节蛋白(HIF-1α)水平变化,为优化贝伐单抗和放射线联合计划提供依据.方法 用HIF-1α荧光蛋白报告质粒转染NCI-H441细胞连续测定肿瘤乏氧水平,并观察贝伐单抗与放射线(122Scγ射线)早晚联合后HIF-1α水平变化、血管数量和渗透性、肿瘤反应、乏氧分子标记、凋亡率和肿瘤生长延迟的异同.结果 单纯贝伐单抗作用后24 h肿瘤HIF-1α表达水平较对照组轻度下降(3.1×106:6.1×106;t=-1.73,P>0.05),功能血管密度升高(16.6:12.1;t=-1.40,P>0.05)和血管渗透指标明显改善(2.9%:11.5%;t=6.80,P<0.01);随后HIF-1α表达水平迅速升高(7.4×106:20.4×106;t=2.36,P<0.05)并维持至疗后8～10 d(第3天时高于对照组3～4倍)且总血管密度明显下降(37.4:15.9;t=5.36,P<0.01).贝伐单抗治疗72 h后联合放射线作用组比24 h后联合作用组肿瘤血管记数高(联合作用后第3天,9.33:3.17;t=-2.43,P<0.05)、凋亡记数低(联合作用后第3天,23.33:43.83;t=2.54,P<0.05),生长延迟时间也明显缩短(10.5:23.0;t=2.67,P<0.05).结论 贝伐单抗联合放射线作用后72 h贝伐单抗诱导的乏氧对血管和肿瘤细胞具有明显的放射抵抗作用,提示血管靶向药物联合放射作用可能存在时间增益窗口.

abstractsObjective To evaluate the impact of the hypoxia induced by bevacizumab on the antitumor effect in combining with irradiation in CNI-H441 xenografts in mice. Methods Bevacizumab of 5 mg/kg mouse for groups of control, bevacizumab alone, irradiation alone, earlier combination (EC), and later combination (LC) were initially injected peritoneally. Single irradiation of 14 Gy (122Sc γ-ray) was given at the 4th hour for the group of irradiation alone, 24th hour for EC group, and 72nd hour for LC group after the initial injection. Tumor hypoxia, micro vessels density and permeability of tumor vasculature,pathological responses, apoptosis, and tumor growth delay curve were evaluated after using bevacizumab and/or irradiation. Results Although it was lower than the control at the 24 hr after using bevacizumab (3. 1 × 106: 6.1 × 106 ;t = - 1.73 ,P > 0. 05), the HIF-1α rapidly increased to 3 - 4 times and 2 - 3 times of the control at day 3 (7.4 × 106: 20. 4 × 106; t = 2. 36, P < 0. 05) and lasted until day 10, which was consistent with the changes of tumor function vessels count. The count of residual micro vessel density count in LC group was higher than that in groups of EC and irradiation at day 3 after irradiation (9. 33: 3. 17;t =- 2. 43, P < 0. 05). The apoptotic count of tumor cells was lower in LC group than that in EC group (23.33: 43.83; t= 2.54, P< 0.05, at day 3 after radiation). Tumor growth delay time of LC groupwas shorter than that of EC groups (10. 5 days vs. 23. 0 days , t = 2. 67 , P < 0. 05) . Conclusions Hypoxia level induced by bevacizumab decreases the antitumor effect in later combination of bevacizumab and irradiaion. It shows a time window that determines whether the combination of bevacizumab and irradiation will be benefit or diverse.