Role of WNT-EGFR crosstalk by EVs and exomeres in normal colon and colon cancer

项目3摘要（科菲） Coffey实验室已经确定了西妥昔单抗（CTX）耐药中WNT和EGFR信号之间的重要联系 和肠腺内环境稳定我们最近报道了一种新的CTX耐药模式， 由miR-100/-125b介导的信号传导。这两种miR在释放的细胞外囊泡（EV）中上调 这些EV可以转移CTX耐药性。在独特的EGFR和WNT报告小鼠中 模型，我们表明，激活WNT信号在EGFR致敏的背景下显着增加， EGFR和非细胞自主WNT活性。基于这些发现，我们提出了一个模型， 结肠干细胞龛（SCN）中EGFR和WNT活性的梯度有助于体内平衡， 梯度的破坏是肿瘤转化的特征。我们假设在正常的隐窝龛中 由EGFR-活性和WNT-活性隔室释放的EV和外泌体增强EGFR-WNT 在CRC中，这些纳米颗粒用于驱动肿瘤生长并定义癌症进展，这是由于它们的 致癌改变的成分。该模型还提供了一个框架，以进一步研究电动汽车的作用， 外泌体至少部分地通过增加的WNT信号传导赋予CTX抗性。为了检验这个模型 并确定电动汽车如何参与CTX耐药性，最终目标是制定策略， CTX抗性，我们提出三个目标。目的1是确定从大肠杆菌中分离的EV和外泌体的作用。 对报告细胞系中EGFR和WNT活性具有高度信息性的配对细胞系。目的二是检验假设 这些EV和外泌体调节正常干细胞模式和肿瘤进展， EGFR和WNT报告基因小鼠模型及其衍生的类器官。目的3是阐明 EV参与EGFR阻断耐药的基础。这项工作有可能改变我们的 对正常干细胞功能、肿瘤生长调节和调节过程的基本了解 耐药性

Project 3 Summary (Coffey) The Coffey lab has identified important links between WNT and EGFR signaling in cetuximab (CTX) resistance and intestinal crypt homeostasis. We recently reported a new mode of CTX resistance due to increased WNT signaling mediated by miR-100/-125b. These two miRs are upregulated in extracellular vesicles (EVs) released by CTX-resistant cells and these EVs can transfer CTX resistance. In a unique EGFR and WNT reporter mouse model, we show that activation of WNT signaling in an EGFR-sensitized background dramatically increases both EGFR and non-cell autonomous WNT activity. Based on these findings, we propose a model of opposing gradients of EGFR and WNT activity in the colonic stem cell niche (SCN) that contribute to homeostasis and disruption of the gradient is a feature of neoplastic transformation. We hypothesize that in the normal crypt niche EVs and exomeres released by the EGFR-active and WNT-active compartments reinforce the EGFR-WNT gradient and in CRC these nanoparticles serve to drive tumor growth and define cancer progression due to their oncogenically altered constituents. The model also provides a framework to further examine the role of EVs and exomeres in conferring CTX resistance, at least in part, via increased WNT signaling. To examine this model and to determine how EVs participate in CTX resistance, with the ultimate goal of devising strategies to overcome CTX resistance, we propose three Aims. Aim 1 is to determine the effect of EVs and exomeres isolated from highly informative paired cell lines on EGFR and WNT activity in reporter cell lines. Aim 2 is to test the hypothesis that these EVs and exomeres regulate normal stem cell patterning and tumor progression using our unique EGFR and WNT reporter mouse models and their derived organoids. Aim 3 is to elucidate mechanistic underpinnings of EV participation in resistance to EGFR blockade. This work has the potential to alter our fundamental understanding of normal stem cell function, regulation of tumor growth and processes regulating drug resistance.