Modulation of death receptor 4 in EGFR-targeted cancer therapy

靶向表皮生长因子受体（EGFR）激活突变，其中90%作为外显子19存在 缺失（Del 19）或21号外显子点突变（L 858 R），使用第一代EGFR酪氨酸激酶抑制剂 （EGFR-TKI;例如，厄洛替尼和吉非替尼）和第三代EGFR-TKI的T790 M耐药突变 (e.g., AZD 9291; TAGRISSO TM或奥希替尼）在非小细胞肺癌患者中提供了显著的临床获益。 细胞肺癌（NSCLC）携带这些突变。不幸的是，对这些EGFR-TKI的耐药性发生在 临床，导致疾病进展。因此，了解潜在的机制和开发 克服EGFR-TKI抗性的有效策略在临床上是非常期望和迫切需要的。 死亡受体4（DR 4;也称为TRAIL-R1或TNFRSF 10A）是肿瘤坏死的细胞表面受体 因子相关凋亡诱导配体（TRAIL）。一般认为，当与蛋白质结合时， TRAIL诱导细胞凋亡;该功能被认为是针对肿瘤的免疫监视的关键机制。 癌细胞然而，DR 4是否发挥其他未知的生物学功能尚不清楚。我们 初步数据表明，用包括AZD 9291，CO 1686， 和厄洛替尼显著降低DR 4水平，主要在EGFR-TKI敏感性EGFR突变型NSCLC细胞中 DR 4的减少与ERK抑制和细胞凋亡的诱导密切相关。 细胞系出乎意料的是，DR 4的敲低增强了TRAIL诱导的细胞凋亡，也增强了AZD 9291的表达。 诱导凋亡。因此，该提议将检验抑制DR 4表达是一种治疗癌症的有效方法的总体假设。 EGFR抑制的靶向结果，并对早期和长期治疗 EGFR靶向治疗的疗效。将通过实现以下具体目标来检验这一假设： (1)证明EGFR抑制剂抑制DR 4表达的机制;（2）了解 DR 4抑制在EGFR靶向癌症治疗中的生物学意义;（3）阐明DR 4抑制对EGFR靶向癌症治疗的影响。 DR 4下调对EGFR靶向治疗疗效的影响 异种移植物（PDX）和来自用EGFR-TKI治疗的NSCLC患者的样品。本提案的目标 旨在证明EGFR抑制导致DR 4降低的分子机制， 了解EGFR靶向癌症治疗中DR 4抑制的生物学意义，并验证 接受EGFR-TKI治疗的NSCLC患者临床标本中的DR 4下调。我们认为 这项建议的结果将具有高度的转化意义，对EGFR靶向的 癌症治疗在诊所 1

Targeting epidermal growth factor receptor (EGFR) activating mutations, 90% of which present as an exon 19 deletion (Del19) or exon 21 point mutation (L858R), with first generation EGFR tyrosine kinase inhibitors (EGFR-TKIs; e.g., erlotinib and gefitinib) and the T790M resistance mutation with third generation EGFR-TKIs (e.g., AZD9291; TAGRISSOTM or osimertinib) has provided significant clinical benefit in patients with non-small cell lung cancer (NSCLC) harboring these mutations. Unfortunately, resistance to these EGFR-TKIs occurs in the clinic, resulting in disease progression. Hence, understanding the underlying mechanisms and developing effective strategies to overcome EGFR-TKI resistance is highly desirable and urgently needed in the clinic. Death receptor 4 (DR4; also known as TRAIL-R1 or TNFRSF10A) is a cell surface receptor for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). It is generally thought that its activation, upon binding to TRAIL, induces apoptosis; this function is recognized as a critical mechanism of immunosurveillance against cancer cells. However, whether DR4 exerts other as yet unknown biological functions is unclear. Our preliminary data demonstrated that EGFR inhibition with several EGFR inhibitors including AZD9291, CO1686, and erlotinib substantially decreased DR4 levels primarily in EGFR-TKI-sensitive EGFR-mutant NSCLC cell lines; this DR4 reduction is tightly associated with ERK suppression and induction of apoptosis in the tested cell lines. Unexpectedly, knockdown of DR4 augments TRAIL-induced apoptosis and also enhances AZD9291- induced apoptosis. This proposal thus will test the overall hypothesis that suppression of DR4 expression is an on-target consequence of EGFR inhibition and has critical impact on both early and long-term therapeutic efficacy of EGFR-targeted therapy. This hypothesis will be tested by accomplishing the following specific aims: (1) to demonstrate the mechanism(s) by which EGFR inhibitors suppress DR4 expression; (2) to understand the biological significance of DR4 suppression in EGFR-targeted cancer therapy; and (3) to elucidate the effect of DR4 downregulation on the efficacy of EGFR-targeted therapy using preclinical NSCLC patient-derived xenografts (PDXs) and samples from NSCLC patients treated with EGFR-TKIs. The objectives of this proposal are to demonstrate the molecular mechanism underlying DR4 reduction caused by EGFR inhibition, to understand the biological significance of DR4 suppression in EGFR-targeted cancer therapy, and to validate DR4 downregulation in clinical specimens from NSCLC patients receiving EGFR-TKIs. We believe that the outcomes of this proposal will be of high translational significance with immediate impact on EGFR-targeted cancer therapy in the clinic. 1