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WNT和EGFR信号之间在西妥昔单抗(CTX)耐药性中的重要联系 和肠腺的动态平衡。我们最近报道了一种新的CTX耐药模式，这是由于WNT增加所致 MiR-100/-125b介导的信号转导。这两个miR在释放的细胞外小泡(EVS)中上调 通过CTX耐药细胞，这些EV可以转移CTX耐药。在一个独特的EGFR和WNT报告小鼠中 模型中，我们发现在EGFR敏化的背景中WNT信号的激活显著增加了 EGFR和非细胞自主的WNT活性。基于这些发现，我们提出了一个对立的模型。 结肠干细胞巢(SCN)中EGFR和WNT活性的梯度，有助于动态平衡和 梯度的破坏是肿瘤转化的一个特征。我们假设在正常的墓穴壁龛里 由EGFR活性和WNT活性的隔室释放的EV和外显子加强了EGFR-WNT 梯度和在结直肠癌中，这些纳米颗粒用于驱动肿瘤生长和定义癌症进展，因为它们的 致癌改变的成分。该模型还提供了一个框架，以进一步审查电动汽车和 外显子至少部分地通过增加WNT信号来传递CTX抗性。要检查此模型 并确定电动汽车如何参与CTX耐药性，最终目标是制定策略，以克服 针对CTX耐药性，我们提出了三个目标。目的1是确定分离的EVS和外显子的作用。 报告细胞系中EGFR和WNT活性的高信息量配对细胞系。目标2是检验这一假设 这些EV和外显子通过我们独特的 EGFR和WNT报告小鼠模型及其衍生的有机化合物。目标3是阐明机械原理 电动汽车参与抵抗EGFR封锁的基础。这项工作有可能改变我们的 对正常干细胞功能、肿瘤生长调控和过程调控的基本认识 抗药性。

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.