xCT和促血管生成因子在胶质瘤组织中肿瘤相关巨噬细胞的表达及意义

Role of xCT and angiogenic factors in gliomas-derived tumor-associated microglia and macrophages

目的:探讨xCT和促血管生成因子在胶质瘤组织中肿瘤相关巨噬细胞(TAMs)中的表达,以及TAMs对胶质瘤进展的影响。方法:分离并培养人新鲜胶质瘤和正常脑组织中的TAMs。采用荧光实时定量(RT-PCR)技术检测M2表型标记物CD14和CD86,促血管生成因子Arg-1和CD209,以及xCT mRNA表达水平。组织冰冻切片免疫荧光染色检测CD68和xCT在胶质瘤中的表达。结果:xCT和CD68在胶质母细胞瘤(WHO°Ⅳ)中的表达明显高于WHO°Ⅱ胶质瘤和正常脑组织,且xCT和CD68共同表达于小胶质细胞中。xCT mRNA在分化程度差的胶质瘤中表达明显增高。此外,小胶质细胞M2表型标记物表达水平(CD14和CD86)、活化状态的TAMs数目和促血管生成因子(Arg-1和CD209)与肿瘤分级相关。结论:TAMs能够通过xCT过表达,促炎症因子和促血管生成因子促进胶质瘤的发展。肿瘤中M2表型的TAMs募集与脑胶质瘤的不良预后相关。

Objective:To investigate xCT and angiogenic factors in relation to tumor-associated microglia and macrophages(TAMs),as these cells highly infiltrate glioblastoma favoring tumor progression.Methods:Brain tissue samples from patients with glioblastoma or epilepsy(control group)were obtained during surgical treatment,homogenized and the conditioned media of TAMs.RNA was isolated and qRT-PCR regarding M2 phenotype markers(CD14 and CD86),pro-angiogenic markers(Arg-1 and CD209)and xCT(SLC7A11)mRNA were performed.Frozen sections were used for immunofluorescence staining.Results:xCT mRNA was upregulated in glioblastoma,but not in normal brain or astrocytomas WHO°Ⅱ.xCT on snap-frozen specimens co-localized also with CD68,a more general microglia marker,confirming the presence of xCT on these immune cells.Furthermore,xCT mRNA level was higher in glioblastoma than that in astrocytomas WHO°Ⅱ,°Ⅲor control,supporting the potential role of TAMs in glioblastoma development.The expression of M2 phenotype markers on microglia cells differed between tissue samples,while activation status of TAM depends on the tumor grade.Conclusion:TAMs are able to support progression of gliomas by over-expressions of xCT,pro-angiogenic markers and pro-angiogenic factors.The recruitment and increased density of M2 phenotype TAMs in the tumors is associated with poor prognosis in cancer patients.