ECM geometrical and mechanical properties modulate RTK signaling

 描述(申请人提供)：受体酪氨酸激酶(RTK)扩增或RTK信号通路的一个或多个成分的不适当激活在许多侵袭性、耐药肿瘤中发生，包括三阴性乳腺癌、肺癌和胰腺癌。RTK信号的临床重要性推动了靶向治疗的发展，旨在阻断受体激活和下游信号传递。RTK抑制剂可以有显著的短期益处，然而患者经常出现复发的RTK抑制剂耐药肿瘤。我们的目标是了解这种治疗失败的根本原因。治疗耐药可能是由于细胞间的 遗传或表观遗传RTK信号的异质性。细胞外基质(ECM)的肿瘤微环境在物理和生物化学上是异质性的，我们和其他人发现ECM的空间力学特征对RTK信号转导有着深刻的影响。我们的论文认为，除了遗传变异之外，来自ECM的外部空间-机械因素也是RTK治疗抵抗的关键原因。我们预测，ECM环境中的利基环境可能会保护一些癌细胞免受RTK抑制剂治疗的影响，从而有利于肿瘤克隆的存活，并增加这些恶性细胞发生“有益”突变的可能性，这些突变增加了它们的侵袭性，并最终危及患者的生存。然而，ECM的空间机械信号调控RTK信号的分子机制仍不清楚。格罗夫斯实验室已经开发出坚固的支持类脂膜平台，以研究信号组装中蛋白质的动力学，无论是在重组过程中，还是在与活细胞的杂交连接中。利用这些系统，Groves和他的同事证明了RTK及其效应器在质膜上的空间组织调制了信号转导的启动。Weaver团队拥有一套二维和三维器官培养系统，以及一套新颖的转基因小鼠模型，在这些模型中，细胞外基质的机械和形态以及糖基化都可以控制，从而能够在培养和体内进行精确的研究。Weaver表明，细胞外基质的机制和形态以及缺氧诱导的笨重的糖基化改变了RTK信号；可能是通过改变膜的几何形状和RTK效应器的活性。在这里，格罗夫斯和韦弗结合他们的专业知识来测试特定的分子机制，通过这些机制，来自ECM的空间机械信号改变RTK信号。他们将专注于RAS；一个GTPase作为关键的RTK信号转导节点，并询问物理调节对其脂双层、细胞和体内平台中RAS激活的影响。这些研究将揭示细胞微环境调节RTK信号并导致耐药的分子机制。从这一认识出发，相互耦合的分子机制将成为降低癌症患者RTK抑制剂耐药性的新靶点。

 DESCRIPTION (provided by applicant): Receptor tyrosine kinase (RTK) amplification or inappropriate activation of one or more components of the RTK signaling pathway occur in many aggressive, treatment resistant tumors including triple negative breast cancer, and lung and pancreatic cancers. The clinical importance of RTK signaling has motivated the development of targeted therapies designed to block receptor activation and downstream signal transmission. RTK inhibitors can have dramatic short-term benefits, however patients frequently present with recurrent, RTK inhibitor resistant tumors. Our goal is to understand the fundamental origins of this therapeutic failure. Treatment resistance can arise due to cell-to-cell genetic or epigenetic RTK signaling heterogeneity. The extracellular matrix (ECM) tumor microenvironment is physically and biochemically heterogeneous and we and others find that the spatial-mechanical features of the ECM exert profound effects on RTK signaling. It is our thesis that in addition to genetic variation, external spatial-mechanical factors from the ECM are a critical cause of RTK therapy resistance. We predict that ECM environmental niches may protect some cancer cells from RTK inhibitor treatments, thus favoring the survival of tumor clones and enhancing the probability of these malignant cells developing `beneficial' mutations that increase their aggression and ultimately compromise patient survival. Yet, the molecular mechanisms whereby spatial-mechanical cues from the ECM regulate RTK signaling remain unclear. The Groves lab has developed robust supported lipid membrane platforms to study dynamics of proteins in signaling assemblies, both in reconstitution and in hybrid junctions with living cells. Using these systems Groves and colleagues demonstrated that the spatial organization of RTKs and their effectors at the plasma membrane modulate signal transduction initiation. The Weaver group has an arsenal of 2- and 3-dimensional organotypic culture systems and a suite of novel transgenic mouse models in which ECM mechanics and topography and the glycocalyx can be controlled, enabling precision studies in culture and in vivo. Weaver showed that ECM mechanics and topography and a hypoxia induced bulky glycocalyx alter RTK signaling; likely by altering membrane geometry and RTK effector activity. Here Groves and Weaver combine their expertise to test specific molecular mechanisms by which spatial-mechanical cues from the ECM alter RTK signaling. They will focus on Ras; a GTPase as a key RTK signaling node and interrogate the impact of physical modulations on Ras activation in their lipid bilayer, cellular, and in vivo platforms. These studies will reveal te molecular mechanisms by which the cellular microenvironment modulates RTK signaling and contributes to treatment resistance. From this understanding, the molecular mechanisms of coupling themselves will emerge as new targets to reduce incidence of RTK inhibitor resistance in cancer patients.