摘要
目的:观察血管内皮细胞生长因子(vascular endothelial cell growth factor,VEGF)信号对溃疡性结肠炎(ulcerativecolitis,UC)癌变的影响并探讨其作用机制。方法:建立小鼠肠炎相关结直肠癌(colitis-associated colorectal cancer,CAC)模型,用流式细胞术和real-time PCR分别检测模型小鼠外周血、脾脏、骨髓及瘤组织中髓样来源的抑制性细胞(myeloid-derived sup-pressor cell,MDSC)的比例和MDSC中精氨酸酶1(arginase-1,Arg-1)和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)mRNA的表达,ELISA法检测结肠和CAC组织培养上清中VEGF的表达。以索拉菲尼(sorafenib)或VEGF单抗阻断VEGF信号后,检测小鼠结肠和CAC部位MDSC比例的变化和病理改变。结果:成功建立小鼠CAC的模型,并根据多项评价指标确定建模后1个月和3个月为CAC的早期和晚期。在CAC形成过程中,小鼠体内Gr-1+CD11b+MDSC细胞数量明显增多,病灶部位MDSC的积聚尤甚,对照组为(0.30±0.18)%、CAC早期组为(1.32±0.04)%、CAC晚期组为(3.08±0.29)%(P<0.05)。这些MDSC细胞高表达Arg-1和iNOS(P<0.05),但病灶部位L-精氨酸含量显著降低[早期组为(4.22±0.17)μg/ml、晚期组为(2.95±1.08)μg/ml、对照组为(4.41±0.16)μg/ml,P<0.05]。此外,与对照组相比,CAC早期和晚期病灶组织高表达VEGF[CAC早期组为(1170±94.43)pg/ml、晚期组为(1117±71.92)pg/ml、对照组为(877.6±31.67)pg/ml,P<0.05]。索拉菲尼或VEGF抗体的治疗可显著抑制病灶部位MDSC的积聚。结论:VEGF信号在CAC形成过程中发挥重要的促瘤功能,其作用机制可能与诱导MDSC在病灶部位的聚集有关。
Objective:To investigate the role and mechanism of vascular endothelial growth factor(VEGF)signaling in the development of ulcerative colitis(UC)-related cancer.Methods:Colitis-associated colorectal cancer(CAC)model was established in Balb/c mice.The proportion of myeloid-derived suppressor cells(MDSCs)in the peripheral blood,spleen,bone marrow and tumor tissues of the model mice and lesions was examined by flow cytometry.Arginase-1(Arg-1)mRNA and inducible nitric oxide synthase(iNOS)mRNA expressions in MDSCs were detected by qPCR.The VEGF expression in the supematants of colonic tissues was determined by ELISA.Sorafenib or neutralizing anti-VEGF antibodywas used to block VEGF signaling and the proportion of MDSC in colonic lesions and the histopathology of CAC were de-tected.Results:Murine CAC model was established successfully.1 month and 3 months after the beginning of CAC were verified as the early and late stages of CAC respectively,according to several parameters.The increased number of Gr-1+CD11 b+MDSC was observed in the progression of CAC and was more significant in lesions:control(0.30±0.18)%,early stage of CAC(1.32±0.04)%,late stage of CAC(3.08±0.29)%(P〈0.05).These MDSCs expressed a high level of Arg-I and iNOS(P〈0.05).But the levels of L-arginine in colonic lesions of CAC mice was much lower than controls(early stage of CAC[4.22±0.17]μg/ml,late stage of CAC[2.95±1.08]p,g/ml,control[4.41±0.16]p,g,/ml,P〈0.05).Furthermore,VEGF expression in the lesions of CAC mice was elevated significantly(early stage of CAC[1170±94.43]pg/ml,late stage of[1117±71.92]pg/ml,control[877.6±31.67]pg/ml,P〈0.05).The treatment of sorafenib or anti-VEGF dramatically reduced accumulation of MDSC in the lesions.Conclusion:VEGF plays a pro-tumor role in CAC formation,which may be related with the induced accumulation of MDSC in colonic tissues.
出处
《中国肿瘤生物治疗杂志》
CAS
CSCD
北大核心
2013年第2期159-165,共7页
Chinese Journal of Cancer Biotherapy
基金
国家重点基础研究发展计划(973计划)资助项目(No.2007CB512406)
国家自然科学基金资助项目(No.30801029,No.81272320)
