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目的:观察EGFR(epidermal growth factor receptor)和IGFR-1β(insulin-like growth factor receptor-1β)的相互作用,探讨IGFR-1β对吉非替尼(gefitinib)抑制结肠癌细胞增殖的影响。方法:以免疫共沉淀法和Western blotting检测EGFR和IGFR-1β之间以及受体与下游信号通路蛋白AKT、MAPK的结合。以IGFR-1酪氨酸激酶抑制剂AG1024和吉非替尼单独或联合作用于3种结肠癌细胞(LoVo,HT29,HCT116细胞),MTT法检测细胞增殖率。结果:LoVo细胞(吉非替尼敏感型)在有或无吉非替尼作用下均不出现与EGFR结合的IGFR-1β条带,HT29细胞(吉非替尼中度敏感型)在吉非替尼作用下可见该条带,而HCT116细胞(吉非替尼耐受型)在有或无吉非替尼作用下均可见条带。LoVo细胞的吉非替尼作用组、HT29细胞的联合用药组以及HCT116细胞的AG1024作用组EGFR结合的AKT、MAPK显著减少(P<0.05)。LoVo细胞在吉非替尼组的细胞增殖率较对照组明显下降(P<0.05),AG1024单独组的增殖率无明显降低,联合用药组与吉非替尼单独组相比较并未进一步降低;HT29细胞在单独应用吉非替尼或AG1024时增殖率均无明显降低,联合用药组的增殖率显著下降(P<0.05);HCT116细胞在吉非替尼作用下增殖率无明显降低,但在AG1024作用下增殖率显著降低(P<0.05),联合用药组与AG1024单独作用组相比较并未进一步降低。结论:结肠癌细胞耐受吉非替尼作用可能或者部分可能与EGFR/IGFR-1β异二聚体形成激活IGFR-1β信号通路有关,抑制IGFR-1β活性在一定程度上可以提高结肠癌细胞对吉非替尼的敏感性。
OBJECTIVE: To observe the interaction between epidermal growth factor receptor (EGFR) and IGFR-1β (insulin-like growth factor receptor-1β) and to investigate the effect of IGFR-1β on the proliferation of colon cancer cells treated with gefitinib. Methods: The co-immunoprecipitation and Western blotting were used to detect the binding of EGFR to IGFR-1β and the downstream signal pathway proteins AKT and MAPK. Three kinds of colon cancer cells (LoVo, HT29, HCT116 cells) were treated with AG1024 and gefitinib, IGFR-1 tyrosine kinase alone or in combination. The cell proliferation rate was detected by MTT assay. RESULTS: The IGFR-1β band that bound to EGFR was not found in LoVo cells (gefitinib-sensitive) with or without gefitinib. HT29 cells (gefitinib moderately sensitive) This band was seen under the effect of Tenin, whereas HCT116 cells (gefitinib-tolerant) showed bands with and without gefitinib. The EGFR-associated AKT and MAPK in gefitinib-treated LoVo cells, HT29-treated cells and AG1024 cells in HCT116 cells were significantly decreased (P <0.05). The proliferation rate of LoVo cells in gefitinib group was significantly lower than that in control group (P <0.05), while the proliferation rate of AG1024 alone group was not significantly reduced. The combined drug group and gefitinib alone group did not reduce further; The proliferation rate of HT29 cells treated with gefitinib or AG1024 alone was not significantly reduced (P <0.05), while the proliferation rate of HCT116 cells treated with gefitinib was not significantly reduced AG1024 significantly reduced the proliferation rate (P <0.05), the combination group and AG1024 alone group did not reduce further. CONCLUSION: The colon cancer cells resistant to gefitinib may be partially or partially related to the activation of IGFR-1β signaling pathway by the formation of EGFR / IGFR-1β heterodimer. Inhibition of IGFR-1β activity may, to a certain extent, enhance the response of colon cancer cells Gefitinib sensitivity.