CD133鉴定胶质瘤干细胞血管周围壁龛的实验研究

目的 检测脑肿瘤干细胞(BTSC)标记物CD133、巢蛋白(Nestin)和增殖细胞核抗原(PCNA)在74例脑胶质瘤标本中的表达,探讨肿瘤干细胞生存的微环境一壁龛的组成、形态及其在脑肿瘤组织中的分布. 方法 选取安徽医科大学附属省立医院神经外科自2007年1月至2008年10月间手术切除的74例胶质瘤标本,按照WH02000年的神经系统肿瘤分类分级标准分为Ⅱ级22例(低级别组)、Ⅲ级27例和Ⅳ级25例(高级别组),采用免疫组织化学染色和免疫荧光双标法分别检测标本中CD133的表达及其与Nestin、PCNA的共表达情况.计算并比较不同级别胶质瘤组织CD133+细胞、CD133+血管和CD133+壁龛所占的百分比.并对CD133+血管和CD133+壁龛的表达进行相关性分析. 结果 CD133+细胞聚集于壁龛内生长,低级别组胶质瘤中CD133+壁龛阳性率较低.壁龛内增殖细胞较少,与相邻肇龛之间界限清晰,周围CD133+血管分布较少.高级别组胶质瘤中CD133+壁龛阳性率高,壁龛之间无明显界限,壁龛内细胞增殖活跃,周围可见丰富的CD133+血管分布:壁龛中除CD133+/Nestin+BTSC外,可见CD133+/Nestin-细胞、CD133/PCNA+细胞等亚群细胞;不同级别胶质瘤CD133+细胞、CD133+血管、CD133+壁龛百分比不同,且肿瘤级别越高,三者表达越高,差异有统计学意义(P<0.05).CD133+壁龛与CD133+血管的表达呈正相关(r=0.425,P=0.000). 结论 在脑胶质瘤组织中存在着由CD133+/Nestin+BTSC和一些亚群细胞组成的壁龛结构,CD133+血管对于壁龛结构的维持起着非常重要的作用.

CD133 in identifying perivascular niche of glioma stem cells

Objective To investigate the expressions of the putative brain tumor stem cell (BTSC) marker CD133, nestin and proliferating cell nuclear antigen (PCNA) in formalin-fixed and paraffin-embedded gliomas, and discuss the BTSC microenvironment: the composition, morphology and distribution of the niche. Methods The samples of 74 patients performed resection of the glioma in our hospital from January 2007 and October 2008 were chosen. According to WHO 2008 classification of nervous system tumors, they were assigned into low-grade glioma group (grade Ⅱ, 22) and high-grade glioma group(grade Ⅲ, 27 and grade Ⅳ,25). Immunohistochemistry was used to detect the expression of CD 133 in 74 cases of brain gliomas. Double immunofluorescence staining was employed to detect the co-expressions of CD133/nestin or CD133/PCNA. The percentages of the CD133+cells, CD133+ blood vessels and CD 133+ niches were calculated, and correlation analysis was also performed on their percentage and the pathological grading of the tumor. Results Accumulated CD 133+ cells grew in the niches. CD 133+ niches could be observed in all grade gliomas; low-grade group showed lower level expression of the CD 133+ niches, fewer proliferating cells, clearer boundary between the 2 neighboring niches and fewer surrounding blood vessels as compared with high-grade group. Besides CD113+/nestin+ BTSCs, some subsets as CD133+/nestin-cells and CD133-/PCNA+ cells were noted in the niches in the high-grade group. The percentages of CD 133+ cells, CD 133+ blood vessels and CD 133+ niches were different in different grades of gliomas and the higher the grade of gliomas was, the higher their expressions were. Positive correlation was observed between the percentage of CD 133+ niches and the percentage of CD133+ blood vessels (r=0.425, P=0.000). The expression of CD133+ niches in high-grade glioma were higher than that in low-grade tumors (F=5.324, P=0.002). Conclusion Glioma tissues have niche structures, which composed of CD133+/nestin+ BTSCs and some subsets. CD133+ blood vessels were playing a key role in maintaining the niche structure, and the expression of CD133+ niches is statistically different in different pathological grading tumors.