Objective To investigate the roles of insulin -like growth factor Ⅰreceptor ( IGF-1R) signal path-way and epithelial-mesenchymal transition ( EMT) in the acquired resistance of epidermal growth factor receptor -tyro-sine kinase inhibitors (EGFR-TKIs) in EGFR wild-type and K-ras mutant non -small cell lung cancer (NSCLC) A549 cells.Methods The EGFR wild-type and K-ras mutant human NSCLC A549 cells were used in this study.The gefitinib-resistant A549 cells (named as A549/GR cells) were created by repeated exposure to gefitinib .MTT assay was used to measure the cell proliferation .Wound-healing array and transwell array were used to determine the invasive and migratory capabilities of cells .The gene and protein expressions of E -cadherin, vimentin, IGF-1R, AKT, ERK and EGFR were determined by qRT -PCR and Western blot, respectively.Results The A549/GR cells acquired resistance to EGFR-TKIs, with significantly reduction in sensitivity to gefitinib (P<0.05).Compared with A549 cells, A549/GR cells presented with mesenchymal phenotype , accompanied by significant enhancement of invasion and migration ( P<0.05).The expression of mesenchymal cell marker vimentin was also significantly increased in A 549/GR cells ( P<0.05), with significant reduction in expression of epithelial cell marker E -Cadherin (P<0.05).No significant differ-ence was found in the expression of IGF -1R mRNA, protein or its phosphorylated form between A 549 and A549/GR cells (P>0.05);while the expression of ERK in A549/GR cells were significantly increased (P<0.05), accompanied with significant up-regulation of mRNA level and phosphorylation level of AKT (P<0.05).The expression of EGFR and its phosphorylated form were significantly reduced in A 549/GR cells as compared with those in A549 cells (P<0.05).Con-clusion EMT and the activation of both AKT and ERK signal pathways may play important roles in acquired EGFR -TKIs-resistance in EGFR wild-type and K-ras mutant NSCLC A549 cells, in which the IGF-1R is not involved .%目的：探讨胰岛素样生长因子Ⅰ型受体（ IGF-1R）信号通路及上皮-间质转化（ EMT）对EGFR野生型、K-ras突变型非小细胞肺癌A549细胞表皮生长因子酪氨酸激酶抑制剂（ EGFR-TKIs）获得性耐药的作用。方法选用EGFR野生型、K-ras突变型的非小细胞肺癌A549细胞，用吉非替尼将其诱导成耐药细胞A549/GR。MTT法检测细胞增殖，划痕实验及Transwell侵袭实验检测细胞侵袭转移能力，qRT-PCR和Western blot 法分别检测EMT标志分子及IGF-1R信号通路相关分子的mRNA和蛋白表达。结果 A549/GR对吉非替尼的敏感性显著下降（P＜0.05）。与A549细胞比较，A549/GR细胞形态呈现间质化改变，侵袭和转移能力均显著增加（P＜0.05）。 A549/GR细胞中间质标志Vimentin的mRNA和蛋白表达量均显著增多（P＜0.05），上皮标志E-Cadherin表达量显著减少（P＜0.05）。与A549细胞相比，A549/GR细胞IGF-1R的mRNA和蛋白及其磷酸化表达量均未见明显改变（P＞0.05），而AKT磷酸化水平及其mRNA水平明显上调（P＜0.05），ERK蛋白及其磷酸化和mRNA表达量均明显增加（ P＜0.05）。 A549/GR 细胞的 EGFR 及其磷酸化蛋白表达量较 A549细胞明显下降（ P＜0.05）。结论 EMT及AKT和ERK信号通路的激活均可能在EGFR野生型、K-ras突变型A549细胞的EGFR-TKIs获得性耐药中起重要作用，但获得性耐药与IGF-1R表达无关。
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