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

项目总结：本研究项目的长期目标是了解二聚化在 癌症中表皮生长因子受体的胞外区(ECD)。短期目标是 设计用于治疗肺癌的向日葵胰蛋白酶抑制因子(SFTI)接枝肽。近85%的肺癌 患者患有一种名为非小细胞肺癌(NSCLC)的癌症。非小细胞肺癌患者的五年生存率 十多年来，患者的病情没有改善，因为大多数酪氨酸激酶抑制剂(TKI) 在五年内抵抗治疗。已知EGFR(EGFR、HER2、HER3)的二聚化起关键作用 在NSCLC。除EGFR外，人表皮生长因子受体-2(HER2)基因扩增和HER2 蛋白过度表达或突变似乎在非小细胞肺癌治疗中耐药的发生中起主要作用。 尽管在2-4%的非小细胞肺癌中观察到HER2过表达或突变，但HER2可能是两者的驱动因素 非小细胞肺癌进展与对EGFR的耐药性。了解EGFR二聚体的细节及其抑制 二聚化不仅对HER2的过度表达，而且对EGFR突变的NSCLC有重大影响，这 将填补我们知识的空白。抑制EGFR胞外结构域二聚有重大影响 探讨其对非小细胞肺癌的治疗作用。这将通过将经临床验证的靶域IV作为靶点来实现 人表皮生长因子受体-2(HER2)及其多肽。然而，多肽在以下方面有局限性 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 具有稳定的结构，可以抵抗热、化学和酶降解。这些多肽可以 被嫁接上可以抑制蛋白质相互作用的官能团。接枝肽克服了 多肽作为治疗剂的局限性，并可口服使用。一种嫁接的模拟多肽分子 被设计成与HER2蛋白特异性结合，并抑制EGFR蛋白的二聚化过程。 这种方法是新颖的，因为设计的分子破坏了EGFR同源和异源二聚体。这个 接枝肽抑制EGFR二聚化和改变癌症信号转导的分子机制 还没有被很好地理解。我们建议详细描述抑制EGFR二聚化的机制。 以及接枝肽的生物药学性质。作为概念验证，嫁接的多肽将是 在不同的肺癌模型中进行评估，包括患者来源的小鼠癌细胞模型。我的目标就是 项目是：1)通过抑制以下物质来评估EGFR的蛋白质-蛋白质相互作用的分子机制 HER2激活和EGFR耐药肺癌中的接枝肽及其对下游信号转导的影响 2)评价接枝肽对抑制小鼠肺癌生长的治疗作用；3) 评价接枝肽的口服利用度和生物药剂学性质。这种嫁接的多肽 口服会对产生耐药性的肺癌治疗和生存期产生影响 肺癌患者的比率。

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.