Molecular mechanism of EGFRs protein-protein interaction inhibition by a grafted peptide in NSCLC

项目概述：本研究项目的长期目标是了解二聚化在 在癌症中表皮生长因子受体（EGFR）的细胞外结构域（ECD）。短期目标是 设计向日葵胰蛋白酶抑制剂（SFTI）接枝肽用于治疗肺癌。近85%的肺癌 患者患有一种称为非小细胞肺癌（NSCLC）的癌症。NSCLC的5年生存率 由于大多数酪氨酸激酶抑制剂（TKI）的发展， 五年内对治疗产生抗药性。已知EGFR（EGFR、HER 2、HER 3）的二聚化在肿瘤的发生发展中起关键作用。 在NSCLC中。除EGFR外，人表皮生长因子受体-2（HER 2）基因扩增和HER 2 蛋白质过表达或突变似乎在NSCLC治疗中耐药的发展中起主要作用。 尽管在2-4%的NSCLC中观察到HER 2过表达或突变，但HER 2可能是两者的驱动因素。 NSCLC进展和EGFR耐药。了解EGFR二聚体的细节并抑制 二聚化不仅对HER 2过表达，而且对EGFR突变的NSCLC有显著影响， 会填补我们知识上的空白抑制EGFR细胞外结构域二聚化具有显著影响 对NSCLC的治疗效果。这将通过靶向临床验证的靶向结构域IV来完成。 人表皮生长因子受体-2（HER 2）与肽。然而，肽在生物活性方面具有局限性。 口服生物利用度已知具有二硫键的多环肽，如向日葵胰蛋白酶抑制剂， 具有耐热、化学和酶降解的稳定结构。这些肽可以 接枝有能够抑制蛋白质-蛋白质相互作用的官能团。接枝肽克服了 肽作为治疗剂的局限性，并且是口服可用的。一种接枝的肽模拟物分子， 被设计为特异性结合HER 2蛋白并抑制EGFR蛋白的二聚化过程。 这种方法是新颖的，因为所设计的分子破坏EGFR同二聚体以及异二聚体。的 移植肽如何抑制EGFR二聚化并改变癌症信号传导的分子机制 并没有得到很好的理解。我们建议详细描述抑制EGFR二聚化的机制， 和接枝肽的生物制药性质。作为概念验证，接枝肽将是 在不同的肺癌模型中进行了评估，包括小鼠中患者来源的癌细胞模型。目的在于 本研究的主要目的是：1）探讨EGFR通过抑制蛋白质间相互作用的分子机制， 移植肽及其对HER 2活化和EGFR耐药肺癌下游信号传导的影响 2）评估移植肽对减少小鼠肺肿瘤生长的治疗效果; 3） 以评价接枝肽的口服利用度和生物药学性质。这样的接枝肽， 将对肺癌治疗产生耐药性和生存率产生影响， 肺癌患者的发病率。

Project Summary: The long-term objective of this research project is to understand the role of dimerization in extracellular domains (ECD) of epidermal growth factor receptors (EGFRs) in cancer. The short-term goal is to design sunflower trypsin inhibitor (SFTI)-grafted peptides for treatment of lung cancer. Nearly 85% of lung cancer patients have a type of cancer called non-small-cell lung cancer (NSCLC). The five-year survival rate of NSCLC patients has not improved in more than a decade because most tyrosine kinase inhibitors (TKIs) develop resistance to therapy within five years. Dimerization of EGFRs (EGFR, HER2, HER3) is known to play a key role in NSCLC. Apart from EGFR, human epidermal growth factor receptor-2 (HER2) gene amplification and HER2 protein overexpression or mutation seem to play major roles in the development of resistance in NSCLC therapy. Although HER2 overexpression or mutation is observed in 2-4% of NSCLC, HER2 may be a driver of both NSCLC progression and resistance to EGFR. Understanding the details of dimers of EGFRs and inhibiting dimerization has a significant impact on not only HER2 overexpressed but EGFR-mutated NSCLC, and this would fill a gap in our knowledge. Inhibition of EGFRs extracellular domain dimerization has a significant impact on its therapeutic effect on NSCLC. This will be done by targeting the clinically validated target domain IV of human epidermal growth factor receptor-2 (HER2) with peptides. However, peptides have limitations in terms of oral bioavailability. Multicyclic peptides with a disulfide bond such as sunflower trypsin inhibitors are known to have a stable structure that is resistant to thermal, chemical, and enzymatic degradation. These peptides can be grafted with functional groups that can inhibit protein-protein interactions. Grafted peptides overcome the limitations of peptides as therapeutic agents and are orally available. A grafted peptidomimetic molecule has been designed that specifically binds to the HER2 protein and inhibits the dimerization process of EGFR proteins. This approach is novel because the molecule designed disrupts EGFR homo- as well as heterodimers. The molecular mechanism of how the grafted peptide inhibits EGFR dimerization and alters the signaling for cancer is not well understood. We propose to characterize details of the mechanism of inhibition of EGFR dimerization and the biopharmaceutical properties of the grafted peptide. As a proof-of-concept, the grafted peptide will be evaluated in different models of lung cancer, including patient-derived cancer cell model in mice. Aims in this project are: 1) to evaluate the molecular mechanism of protein-protein interactions of EGFRs via inhibition by the grafted peptide and its effect on downstream signaling in HER2-activated and EGFR-resistant lung cancer cells; 2) to evaluate the therapeutic effect of grafted peptides on reducing the growth of lung tumors in mice; 3) to evaluate the oral availability and biopharmaceutical properties of grafted peptides. Such grafted peptides that are orally available will have an impact on lung cancer treatments that develop resistance and on the survival rate of lung cancer patients.