中文摘要：

目的研究缺氧对人肝癌细胞SMMC-7721黏着斑激酶（FAK）表达的影响以及FAK表达对SMMC-7721细胞侵袭能力的影响。方法通过1％体积分数O2的低氧培养建立人肝癌细胞SMMC-7721物理缺氧模型，Western blot检测FAK的表达。构建针对FAK mRNA的干扰质粒pshRNA-FAK及阴性对照质粒pGensil-2，并将其转染至SMMC-7721细胞，G418筛选稳定转染细胞株。Western blot检测FAK蛋白表达的变化，细胞迁移和侵袭实验检测缺氧条件下细胞迁移和侵袭能力的改变。在正常条件下将FAK真核表达质粒pcDNA3-FAK转染至SMMC-7721细胞，观测其侵袭能力的改变。根据数所资料的不同分别采用f检验、单因素方差分析、LSD法及Dunnett法进行统计学处理。结果低氧培养的SMMC-7721细胞FAK蛋白表达水平逐渐升高，24h后较0h时明显升高（JP〈0．01）。SMMC-7721细胞稳定转染pshRNA-FAK后，FAK蛋白表达显著下降，抑制率达74．6％±5.1％，在正常及缺氧条件下都对FAK表达有显著抑制作用。细胞迁移实验结果显示，缺氧显著促进SMMC-7721细胞迁移能力（t=18．66，P〈0．01），侵袭实验结果与迁移实验结果一致。转染pshRNA-FAK对促进SMMC-7721细胞在缺氧环境中的迁移能力有显著抑制作用，透膜细胞数（353±36）个较对照组（392±31）个明显降低（F=173．983，P〈0．05）；细胞侵袭实验显示，转染pshRNA-FAK对促进SMMC-7721细胞侵袭能力有显著抑制作用，透膜细胞数（160±12）个较对照组（194±13）个明显降低（F=59．674，P〈0．05）。同时转染真核表达质粒pcDNA3-FAK显著促进SMMC-7721细胞侵袭能力。结论缺氧促进SMMC-7721细胞侵袭可能与FAK表达水平升高相关，FAK表达的上调可能是缺氧促进肝癌细胞侵袭转移的机制之一。

英文摘要：

Objective To study focal adhesion kinase （FAK） expression in hypoxia-stressed SMMC- 7721 cells and the role of FAK expression in the hypoxia-induced invasion of SMMC-7721 cells. Methods SMMC-7721 cells were cultured in 21% 02 or 1% O2. FAK expression was determined by Western blot. The siRNA expression vector pshRNA-FAK targeting to FAK and the control vector pGensil-2 were transfected into SMMC-7721 cells. The hypoxia-induced migration and invasion ability of SMMC-7721 cells transfected with pshRNA-FAK were analyzed. In normoxia, invasion of SMMC-7721 cells transfected with pcDNA3-FAK was analyzed. Results The expression of FAK was increased significantly in SMMC-7721 cells 24 h after hypoxia stress （P 〈 0.01）. The level of FAK protein was decreased by 74.6±5.1% after the pshRNA-FAK transfection in normoxia and hypoxia. The migration and invasion of SMMC-7721 cells was increased in 1% O2 （P 〈 0.01）. However, the migration and invasion of SMMC-7721 cells transfected with pshRNA-FAK was decreased in 1% O2 （P 〈 0.05）. Overexpression of FAK significantly stimulated the invasion of SMMC-7721 cells. Conclusion Up-regulation of FAK may play an important role in the invasion of SMMC-7721 cells induced by hypoxia.