低剂量化疗抑制肺癌血管生成的研究

背景与目的近期一些国外研究表明降低化疗药物的剂量可特异地杀伤新生肿瘤血管内皮细胞,利用化疗药物的这一新靶点,可能帮助解决常规化疗剂量引起的毒副作用和耐药性的难题。为此本研究观察持续低剂量环磷酰胺(CTX)对肺癌血管生成的影响,并观察其抑瘤效果和毒副作用。方法建立荷Lewis肺癌C57/BL6小鼠模型,分别给予持续低剂量(LDM)CTX、最大耐受剂量(MTD)CTX治疗,观察肿瘤体积、小鼠体重和外周血白细胞计数及小鼠生存期。实验终末时行免疫组化染色,测定肿瘤微血管密度(MVD)和血管内皮生长因子(VEGF)表达情况。结果与对照组和MTDCTX治疗组比较,LDMCTX治疗组小鼠肿瘤MVD值和VEGF表达均显著降低(P<0.05)。与MTDCTX治疗组比较,LDMCTX治疗组肿瘤生长比较缓慢,并且没有明显的体重减轻或白细胞数下降等毒性迹象,小鼠生存期显著延长(P<0.05)。结论CTX的持续低剂量给药方式靶向于肺癌血管生成,不易产生耐药,增加了抑瘤效果,毒副作用小,动物生存期明显延长。

Antiangiogenic effect of continuous low-dose chemotherapy on Lewis lung carcinoma

Background and objective Recently a number of preclinical studies have sparked interest in the concept of exploiting conventional chemotherapeutic drugs as antiangiogenics. Such antiangiogenic activity is achieved by metronomic-dosing (low-dose) protocols. This new target may have some advantages in avoiding toxicity and resistance caused by chemotherapeutic drugs. This study is to test the efficacy of continuous low-dose cyclophosphamide (CTX) for antiangiogenic effect on Lewis lung carcinoma, and investigate its antitumor effect and toxicity. Methods C57/BL6 mice bearing Lewis lung carcinoma were randomly divided into three groups, receiving low-dose metronomic (LDM) CTX, maximum tolerated dose (MTD) CTX therapy and saline respectively. Tumor growth, weight loss, peripheral white blood cell counts and survival of mice were monitored in each group. At the end of experiment, tumors were resected for immunohistochemical staining. Tumor microvascular density (MVD) and vascular endothelial growth factor (VEGF) level were detected by immunohistochemical staining. Results MVD and VEGF expression of tumors were much lower in the mice received LDM CTX therapy than those in control group and MTD CTX group (P<0.05). During the experiment, growth delays of tumor were found in the mice received LDM CTX therapy, without apparent body weight loss or leukopenia, and the survival of mice was remarkably prolonged, compared with mice received MTD CTX therapy (P<0.05). Conclusion The continuous low-dose regimen of CTX can significantly increase the therapeutic activity with decreased toxicity and prolonged animal survival for lung cancer. It may act as an antiangiogenic and lead to less drug resistance.