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【摘要】 目的 探讨肺癌中支架蛋白IQGAP1的蛋白表达水平，及IQGAP1对肺癌细胞运动侵袭能力的影响。方法 RT-PCR检测IQGAP1 mRNA的表达，免疫组织化学SABC法及Western blot检测IQGAP1蛋白的表达，并采用Transwell实验探讨IQGAP1蛋白促进侵袭转移的作用机制。结果 研究发现其在肺癌组织存在高表达，IQGAP1蛋白可以通过提高肺癌细胞的运动能力促进肺癌的侵袭转移。结论 IQGAP1与肺癌密切相关，可能在肺癌的侵袭和转移中起重要做用。�
【关键词】 肺癌；IQGAP1；细胞运动；侵袭转移��
Expression and clinical significance of IQGAP1 in lung cancer
LENG Shu-ping.
Department of Biochemistry, Daqing Medical College, Daqing 163312,China
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【Abstract】 Objective To investigate the expression of Scaffold protein IQGAP1 in lung cancer, and the influence to cell invasion and metastasis.Methods The expression of IQGAPI mRNA was studied by RT-PCR, the expression of IQGAPl Protein was analyzed by immunohistochemistry and western blot, invasion and metastasis of IQGAP1was test by Transwell. Results The abnormal high expression of IQGAP1 in lung cancer tissues compared with non-cancerous tissues. The IQGAP1 expression was positive correlated with the survival of lung cancer. IQGAP1 promote lung cancer invasion and metastasis by improve cancer cell motility. Conclusion The IQGAP1 expression is closely related to lung cancer, may play important role in invasion and metastasis in human lung cancer.�
【Key words】 lung cancer; IQGAP1; Cell movement; Invasion and metastasis
1 材料与方法�
收集新鲜肺癌组织标本36份，标本离体后迅速切取肺癌组织；人肺正常细胞；低和高转移肺巨细胞癌细胞株95C和95D。采用半定量逆转录多聚酶链式反应(RT-PCR)检测IQGAP1 mRNA的表达，免疫组织化学SABC法及Western blot检测IQGAP1蛋白的表达。根据IQGAP1在肺癌细胞中表达的部位，将IQGAP1免疫组化阳性染色的肺癌细胞标本分为IQGAP1胞膜表达型和IQGAP1胞浆表达型。比较IQGAP1在各组肺癌细胞中的表达水平、表达类型以及与肺癌的临床病理特征关系。采用具有不同侵袭转移能力的95C细胞株和95D细胞株检测IQGAP1蛋白表达的差异。通过IQGAP1小鼠抗人单克隆抗体阻断SPCA1细胞株中IQGAP1蛋白的功能，并采用Transwell实验探讨IQGAP1蛋白促进侵袭转移的作用机制。�
2 实验结果�
RT-PCR和Western blot研究结果显示肺癌细胞中IQGAP1 mRNA的表达水平见(0.61±0.28)和蛋白表达水平(2101.4±295.6)显著高于正常细胞(0.38±0.26，1012.5±265.7)(P 我们在前面的实验中已经观察到IQGAP1在肺癌组织中存在异常表达，并与肺癌的复发转移密切相关，但其具体的机制尚不清楚。为了弄清IQGAP1对肿瘤细胞侵袭转移能力的影响，我们选用94C和95D细胞系进行研究。结果95D细胞显示较强的侵袭能力，其IQGAP1在基因和蛋白表达水平皆高于侵袭能力较弱的细胞，这与我们在临床标本上的观察结果相一致。从我们免疫组化的实验结果可以清楚的看出，在同一癌组织切片中，并不是所有的肿瘤细胞都高表达IQGAP1其表达最强的部位主要在肿瘤侵袭血管的部位和已经侵入血管的肿瘤细胞中。而侵袭能力高的亚克隆细胞通过其高表达或低表达包括IQGAP1在内的特定蛋白，获得较高的运动能力或较低的肿瘤细胞间黏附力等其他特性，从而具有更大的机会发生侵袭转移［7］。�
IQGAP1是调节细胞运动和黏附的一个核心分子，但其在肺癌中是否也通过增强肺癌细胞运动能力来提高肿瘤的侵袭能力尚不清楚。本文研究结果显示阻断IQGAPl蛋白后95D细胞的运动能力和侵袭能力大为下降，这就确实的说明IQGAP1可以促进肺癌细胞的侵袭转移，其机制之一可能在于IQGAP1能够提高肿瘤细胞的运动能力。�
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