Integrated approach to study early and late events in colonic neoplasia: mouse to man

EGFR参与了许多人类癌症的发生，包括结直肠癌(CRC)，它 是美国第三种最常见的癌症，也是导致癌症死亡的第三大原因 男人和女人。EGFR已成为许多癌症的主要治疗靶点。EGFR的中和 单抗西妥昔单抗被批准用于治疗含有野生型的晚期大肠癌 然而，只有15%的野生型KRAS结直肠癌患者对西妥昔单抗有反应，而患有 突变的KRAS CRC对西妥昔单抗没有反应。我建议应对的癌症研究挑战是： 为什么EGFR阻断对结直肠癌(和其他实体肿瘤)的临床益处如此有限。我建议本局 无法在CRC中更有效地阻止EGFR，至少部分原因是三个问题：1)不完整 对其七种哺乳动物配体触发的EGFR信号转导的复杂性的了解；2)不足 临床前预测模型和3)耐药的出现。通过解决这三个问题中的每一个 问题，这一修订的应用程序的总体目标是显著提高诊断、治疗和 对患有儿童权利公约的个人进行监测。我们的焦点是结直肠癌，从膜-近端的角度来看 与EGFR相关的事件。我们预计，我们所取得的进展将适用于其他实体肿瘤 EGFR信号转导起着非常重要的作用。根据我们最近的发现，EGFR抑制剂Lrig1标志着一个 独特的结肠干细胞群体，并发挥肿瘤抑制作用，以及独特报告的使用 小鼠(Lrig1-Apple，EGFR-EmGFP)，我们建议将结肠肿瘤的关键事件与干细胞和EGFR- 相关事件。我们的实验室已经建立了一个强大的结肠肿瘤模型：在诱导丢失的50天内 在表达Lrig1的结肠干细胞中有一个APC等位基因，会出现多个高度发育不良的结肠腺瘤 可通过结肠镜检查和新型PET成像探针进行监测。这些小鼠将接受第一次治疗 可获得小鼠EGFR中和抗体。在鼠腺瘤中发现的结果将与人腺瘤相关。 使用MulltiOmyx和解剖，我们将在单细胞分辨率和解构的情况下检查肿瘤的情况 肿瘤异质性。使用新开发的3D培养系统，我们发现了一种新的模式 西妥昔单抗耐药通过WNT信号的增强，这是由于编码的长RNA NOT显著上调 以前链接到CRC。我们将进一步阐明这种抗性的机制，并推动这些 临床上的发现。我们将进一步研究EGFR及其配体通过外体和 检测含有EGFR的外切体是否起到诱饵的作用，以减少递送到 肿瘤。我们将利用范德比尔特大学、范德比尔特-英格拉姆癌症中心和 范德比尔特的GI专门研究卓越计划(Spoor)来推进这项工作。

The EGFR contributes to the pathogenesis of many human cancers, including colorectal cancer (CRC), which is the third most commonly diagnosed cancer and the third leading cause of cancer deaths in the US for both men and women. The EGFR has become a major therapeutic target in many cancers. The EGFR neutralizing monoclonal antibody, cetuximab, is approved for the treatment of advanced CRCs that contain wild-type KRAS; however, only 15% of individuals with wild-type KRAS CRC respond to cetuximab, and individuals with mutant KRAS CRC do not respond to cetuximab. The challenge in cancer research I propose to address is: why has EGFR blockade in CRC (and other solid tumors) had such modest clinical benefit. I propose that the inability to more effectively block the EGFR in CRC is due, at least in part, to three issues: 1) an incomplete understanding of the complexity of EGFR signaling triggered by its seven mammalian ligands; 2) inadequate predictive preclinical models and 3) the emergence of drug resistance. By addressing each of these three issues, the overall goal of this revised application is to significantly advance the diagnosis, treatment and monitoring of individuals with CRC. Our focus is CRC, viewed from the perspective of membrane-proximal EGFR-related events. We anticipate that advances we make will be applicable to other solid tumors in which EGFR signaling plays a prominent role. Based on our recent finding that the Egfr inhibitor, Lrig1, marks a distinct population of colonic stem cells and acts as a tumor suppressor, along with the use of unique reporter mice (Lrig1-Apple, Egfr-EmGFP), we propose to link key events in colonic neoplasia to stem cells and Egfr- related events. Our lab has developed a robust model of colonic neoplasia: within 50 days of inducing loss of one Apc allele in Lrig1-expressing colonic stem cells, multiple, highly dysplastic colonic adenomas arise that can be monitored by colonoscopy and novel PET imaging probes. These mice will be treated with the first available mouse Egfr neutralizing antibody. Findings in mouse adenomas will be related to human adenomas. Using MulltiOmyx and DISSECT, we will examine the tumor landscape at single cell resolution and deconstruct tumor heterogeneity. Using a newly developed 3D culture system, we have discovered a novel mode of cetuximab resistance via increased WNT signaling due to marked upregulation of a long con-coding RNA not previously linked to CRC. We will further elucidate the mechanism of this resistance and advance these findings clinically. We will further examine a new mode of signaling by EGFR and its ligands via exosomes and test whether EGFR-containing exosomes act as a decoy to reduce the amount of EGFR antibody delivered to tumors. We will harness the tools and resources at Vanderbilt University, Vanderbilt-Ingram Cancer Center and Vanderbilt's GI Specialized Programs of Research Excellence (SPORE) to advance this work.