CXCR4在胶质瘤细胞中的表达及对迁移的影响

目的 检测趋化因子受体CXCR4在胶质瘤细胞的表达。建立侵袭迁移模型，分析CXCR4在CXCL12作用下对U251细胞迁移的影响机制。方法 间接免疫荧光法检测CXCR4在U251的表达。流式细胞术（flow cytometry，FCM）检测不同病理级别胶质瘤CXCR4的表达。建立琼脂糖下细胞迁移（Under-agarose cell migration assay）模型，研究U251在不同浓度CXCL12下的侵袭能力。设空白组与实验组，实验组以CXCL12浓度分5组。计算趋化系数（chemotaxis coefficient，cc）。结果 ①CXCR4表达于U251细胞。②Ⅰ、Ⅱ、Ⅲ、Ⅳ级别胶质瘤CXCR4表达率分别为21.36±2.70%、26.39±4.27%、52.59±2.37%、56.23±1.24%。四个级别胶质瘤CXCR4的阳性率均有显著差异（P<0.05）。③对照组细胞迁移距离为40.85±5.16μm，实验组细胞迁移距离分别为49±2.26μm、105.6±3.82μm、165.3±3.89μm、245.4±5.94μm、161.45±3.18μm。因子浓度为200~500ng/ml时与阴性组相比细胞发生明显迁移（P<0.05）。结论 ①胶质瘤细胞U251表达CXCR4。②胶质瘤的病理级别越高CXCR4的阳性率越大。③成功建立了胶质瘤细胞琼脂糖下侵袭模型，为研究肿瘤细胞迁移提供新的方法；CXCL12对胶质瘤有明显的趋化作用，肿瘤细胞顺因子浓度梯度定向迁移。

CXCR4 expression in glioma cells and its effect on migration

Objective To determine the expression of the chemokine receptor CXCR4 in glioma cells, and to analyze the mechanism of CXCR4 influencing U251 cell migration under the treatment with CXCL12 by establishing an invasion and migration model.Methods Indirect immunofluorescence assay was used to determine CXCR4 expression in U251 cells, and flow cytometry was used to determine CXCR4 expression in different pathological grades of gliomas. An under-agarose cell migration assay model was established to explore the U251 cell invasion ability under different concentrations of CXCL12.Blank group and experimental group were set up.The experimental group was divided into five groups with CXCL12 concentration.The chemotaxis coefficient was calculated.Results CXCR4 protein was expressed in U251 cells. The expression rates of CXCR4 in grade I, Ⅱ, Ⅲ, and IV gliomas were 21.36%±2.70%, 26.39%±4.27%, 52.59%±2.37%, and 56.23%±1.24%, respectively; there were significant differences between the four grades of gliomas in the positive rate of CXCR4 (P<0.05). The cell migration distance was 40.85±5.16 μm for the control group, and 49±2.26 μm, 105.6±3.82 μm, 165.3±3.89 μm, 245.4±5.94 μm, and 161.45±3.18 μm, respectively, for the experimental groups. The cells showed significant migration at a factor concentration of 200-500 ng/mL as compared with that in the negative group (P<0.05).Conclusions CXCR4 protein is expressed in U251 glioma cells. The CXCR4 positive rate is higher with increasing pathological grades of glioma. An under-agarose cell invasion assay model is successfully established in the glioma cells, which provides a new method for the research on tumor cell migration. CXCL12 shows an obvious chemotactic effect on glioma, and the tumor cells directionally migrate along the factor concentration gradient.