非小细胞肺癌自分泌EGF、TGF-α介导ALK靶向耐药的机制研究

Drug resistance severely limits the clinical therapeutic value of molecular targeted drugs. The mechanism by which epidermal growth factor (EGF) and transforming growth factor alpha (TGF-α) promote drug resistance in non-small cell lung cancer (NSCLC) is unknown. Our preliminary study found that the autocrine level of EGF and TGF-α was up-regulated in TAE684-resistant cells; moreover, both stable expression of EGF or TGF-α and exogenous addition of EGF or TGF-α rescued NCI-H3122 cells from TAE684 sensitivity. These results suggest that EGF and TGF-α are involved in TAE684 resistance . However, differences between EGF and TGF-α driven ALK-targeted drug resistance in terms of potency have yet to be thoroughly examined; furthermore, the mechanism of EGF and TGF-α promoting ALK-targeted drug resistance has not been reported. In this project, we intends to clarify the role of EGF and TGF-α in promoting TAE684 resistance and to explore the difference in the ability of EGF and TGF-α to activate EGFR signal pathway from molecular, cellular, animal and clinical levels. In addition, we place particular emphasis on obtaining a thorough mechanism understanding of the relationship between pre-existing autocrine EGF, TGF-α clone and TAE684 resistance. This current study will provide a theoretical basis for using EGF or TGF-α as a novel biomarker for ALK-targeted drug resistance.

耐药严重限制了分子靶向药物的临床治疗价值。表皮生长因子（EGF）和转化生长因子alpha（TGF-α）参与非小细胞肺癌（NSCLC）靶向耐药的机制尚不清楚。我们前期研究发现，TAE684获得性耐药细胞自分泌EGF、TGF-α的水平升高，且加入外源性EGF、TGF-α或稳定高表达EGF、TGF-α均能降低NCI-H3122细胞对TAE684的敏感性。结果提示EGF、TGF-α参与了TAE684耐药。但EGF、TGF-α贡献ALK靶向耐药的程度差异及EGF、TGF-α驱动ALK靶向耐药的机制未见报道。本课题拟从分子、细胞、动物及临床水平等多层次明确EGF、TGF-α在TAE684耐药中的作用；探讨EGF、TGF-α激活EGFR传导通路的能力差异；揭示预先存在的EGF、TGF-α自分泌克隆介导TAE684耐药的机制。本研究将为EGF、TGF-α作为ALK靶向耐药的生物标志物提供理论依据。

耐药严重限制了分子靶向药物的临床治疗价值。生长因子由于能够促进非小细胞肺癌的耐药而受到极大关注。然而，肿瘤细胞自身是否可以通过分泌生长因子来介导耐药尚不清楚。我们研究发现，低浓度连续递增法构建的ALK抑制剂TAE684获得性耐药细胞H3122/TR和c-Met抑制剂SGX523获得性耐药细胞EBC-1/SR自分泌表皮生长因子（EGF）和转化生长因子α（TGF-α）水平显著升高。同时，敏感细胞H3122、EBC-1分别过表达EGF、TGF-α后对TAE684和SGX523产生耐药。此外，外源性加入EGF、TGF-α诱导了H3122、EBC-1对TAE684和SGX523产生耐药。临床上，与敏感患者相比，Crizotinib原发性耐药患者中的EGF、TGF-α表达显著升高。机制水平上，自分泌EGF、TGF-α激活了旁路EGFR信号通路。联合应用ALK/c-Met抑制剂和EGFR抑制剂均能克服EGF、TGF-α诱导的原发性和获得性耐药。综上所述，非小细胞肺癌自分泌EGF、TGF-α的增加介导了ALK/c-Met TKI的原发性和获得性耐药。