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%存在外显子19 缺失(Del19)或外显子21点突变(L858R)，第一代EGFR酪氨酸激酶抑制剂 (EGFR-TKIs；例如，erlotinib和gefitinib)和第三代EGFR-TKIs的T790M耐药性突变 (例如，AZD9291；TAGRISSOTM或osimertinib)已经为非小细胞肺癌患者提供了显著的临床益处 携带这些突变的细胞肺癌(NSCLC)。不幸的是，对这些EGFR-TKI的耐药性发生在 临床，导致疾病的发展。因此，了解潜在的机制和发展 克服EGFR-TKI耐药的有效策略在临床上非常可取和迫切需要。 死亡受体4(DR4；也称为TRAIL-R1或TNFRSF10A)是肿瘤坏死的细胞表面受体 因子相关凋亡诱导配体(TRAIL)。通常认为，当与其结合时，它的激活 TRAIL，诱导细胞凋亡；这一功能被认为是免疫监控的关键机制 癌细胞。然而，DR4是否发挥了其他未知的生物学功能尚不清楚。我们的 初步数据表明，几种EGFR抑制剂包括AZD9291，CO1686， 厄洛替尼显著降低了EGFR-TKI敏感的突变型NSCLC细胞的DR4水平 这种DR4的减少与ERK抑制和诱导受试者的细胞凋亡密切相关 细胞系。出乎意料的是，DR4的敲除增强了TRAIL诱导的细胞凋亡，并增强了AZD9291- 诱导细胞凋亡。因此，这一提议将检验抑制DR4表达是一种 EGFR抑制的靶向后果，对早期和长期治疗都有关键影响 EGFR靶向治疗的疗效。这一假设将通过实现以下具体目标来检验： (1)论证表皮生长因子受体抑制剂抑制DR4表达的机制(S)；(2)了解 抑制DR4在EGFR靶向肿瘤治疗中的生物学意义；以及(3)阐明其作用 DR4下调对临床前非小细胞肺癌患者EGFR靶向治疗疗效的影响 异种移植(PDX)和接受EGFR-TKI治疗的非小细胞肺癌患者的样本。这项提案的目标是 是为了证明EGFR抑制导致DR4减少的分子机制， 了解DR4抑制在EGFR靶向癌症治疗中的生物学意义，并验证 接受EGFR-TKI治疗的非小细胞肺癌患者临床标本中DR4表达下调。我们相信， 这项提议的结果将具有很高的翻译意义，并对EGFR目标产生直接影响 诊所里的癌症治疗。 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