整合素β1及纤连蛋白、层粘连蛋白对胶质瘤细胞浸润性的影响

目的 探讨整合素β1和纤连蛋白（FN）、层粘连蛋白（LN）对人胶质瘤浸润性的影响和作用机制。方法 以U251人胶质母细胞瘤（U251MG）细胞为研究对象,通过细胞黏附实验、迁移实验和体外侵袭实验,检测整合素β1及LN、FN对人恶性胶质瘤细胞黏附、迁移和转移能力的影响。通过荧光染色结合激光扫描共聚焦显微镜观察和扫描电镜方法,观察细胞微丝数量、分布和细胞表面伪足情况,比较整合素β1及FN、LN对微丝骨架的影响。结果 （1）FN对U251MG细胞黏附能力无明显影响,但抗整合素β1抗体可减少U251MG细胞的黏附数量（P〈0．01）;LN增加U251MG细胞黏附能力（P〈0．01）,抗整合素β1抗体对此作用影响较小。（2）抗整合素β1抗体减弱U251MG细胞在FN的运动、迁移能力（P〈0．05）。（3）U251MG细胞内可见清晰的微丝结构,FN、LN使细胞内纤维型肌动蛋白（F-actin）形成束状纤维,粗壮而密集;抗整合素B1抗体处理的细胞内,难以见到清晰的细胞微丝骨架,并常见大量絮团状的F-actin。（4）扫描电镜观察显示,FN、LN使细胞表面的伪足数量明显增加,而抗整合素β1抗体使细胞伪足数量明显减少,甚至消失。（5）FN和抗整合素β1抗体对U251MG细胞的体外侵袭能力无明显影响;LN可促进U251MG细胞的体外侵袭能力,抗整合素β1抗体可抑制这种作用（P〈0．01）。结论 （1）U251MG细胞通过整合素β1和FN相互作用,改变细胞微丝骨架、伪足结构和数量而促进U251MG细胞的运动、迁移能力。（2）整合素β1参与了LN介导的U251MG细胞体外侵袭作用。

Effects of beta1-integrin, fibronectin and laminin on invasive behavior of human gliomas

OBJECTIVE: To investigate the effects of beta1-integrin, fibronectin (FN) and laminin (LN) on the invasive behavior of human gliomas. METHODS: Functional impacts of beta1-integrin, fibronectin and laminin on cell adhesion, migration and metastasis of U251 malignant glioblastoma cells were investigated by in vitro adhesion, migration and invasion assays. The amount and distributions of cellular microfilaments and pseudopodia were studied by fluorescent cytochemistry, confocal laser scanning microscope and scanning electron microscope. Lastly, beta1-integrin, fibronectin and laminin were investigated for their roles in cellular microfilament skeleton. RESULTS: (1) Fibronectin did not affect cell adhesion of U251MG cells, but anti-beta1 integrin antibodies inhibited cell adhesion (P < 0.01); Laminin stimulated cell adhesion of U251MG cells (P < 0.01) but anti-beta1 integrin antibodies had little effect on the laminin-mediated cell adhesion. (2) The migration of U251MG cells on dishes coated with FN was inhibited by anti-beta1 integrin antibodies (P < 0.05). (3) F-actins formed strong and dense stress fibers in U251MG cells on dishes coated with FN and LN. Anti-beta1 integrin antibodies disrupted the microfilament network and F-actin aggregation. (4) FN and LN increased the number of pseudopodia on cell surface, whereas anti-beta1 integrin antibodies reversed this function. (5) FN and anti-beta1 integrin antibodies had little effects on the invasive ability of U251MG cells in vitro. The invasion was increased by LN, but inhibited by anti-beta1 integrin antibodies. CONCLUSIONS: (1) The interaction between beta1-integrin, FN may stimulate U251MG cell migration via changing the structures of microfilament skeleton and the number of pseudopodia. (2) beta1-integrin may play a role in the LN-mediated in vitro invasion of U251MG cells.