Regulation of metastasis by alpha V integrin and Src

描述（由申请人提供）：整合素和生长因子受体以协同方式调节细胞行为。在上一个资助周期中，我们已经开始探索胰腺癌细胞中的信号传导模块，该模块似乎可以调节这些细胞的转移特性。我们发现表皮生长因子受体（EGFR）与整合素avb 5一起促进Src激酶信号传导，Src激酶信号传导似乎直接调节人和鼠胰腺肿瘤细胞的侵袭特性。我们已经确定了两种途径的肿瘤细胞迁移在体外，可以区分其差异依赖于Src激酶活性。细胞迁移的纤维连接蛋白，胶原蛋白和层粘连蛋白介导的b1整合素是独立的Src，而迁移玻连蛋白介导的整合素avb 5依赖于Src。在初步结果中，我们表明EGFR/Src/avb 5信号传导模块在体内原位和自发胰腺癌细胞转移模型中启动导致肿瘤细胞侵袭的级联反应。我们已经选择了匹配的原代和转移性胰腺细胞系，并发现EGFR的激活或过表达与整联蛋白avb 5的连接似乎诱导Src活性和下游信号传导，导致这些细胞的侵袭行为增加。我们发现，胰腺癌细胞表达增加的Src激酶活性侵入从原发性肿瘤深入到宿主间质，而原发性肿瘤与最小的Src活性保持局限于肿瘤实质内，通过活体多光子成像测量。在这个提议中，我们将描述EGFR/Src/avb 5信号促进侵袭和转移的机制。我们将探讨Src酪氨酸磷酸化的特定底物如何影响这种侵入行为。这些研究将集中在Src如何不仅激活细胞迁移机制，而且如何促进肿瘤细胞粘附连接的解偶联。最后，我们将探讨如何在转移性胰腺癌细胞的EGFR/avb 5/Src信号传导模块的药理学和/或遗传破坏逆转其体内转移表型。在这种情况下，我们将评估这些目标在原位胰腺癌模型中的可能治疗相关性，以及自发性原发性和转移性胰腺癌的遗传模型。这些研究应该提供了一个信号级联的分子洞察力，似乎有助于胰腺癌的侵袭行为。

DESCRIPTION (provided by applicant): Integrins and growth factor receptors function in a cooperative manner to regulate cellular behavior. During the previous funding cycle, we have begun to explore a signaling module in pancreatic carcinoma cells that appears to regulate the metastatic properties of these cells. We found that epidermal growth factor receptor (EGFR) together with the integrin avb5 promotes Src kinase signaling that appears to directly regulate the invasive properties of both human and murine pancreatic tumor cells. We have identified two pathways of tumor cell migration in vitro that can be distinguished by their differential dependence on Src kinase activity. Cell migration on fibronectin, collagen, and laminin mediated by b1 integrins is independent of Src, while migration on vitronectin mediated by integrin avb5 depends on Src. In Preliminary Results, we show that the EGFR/Src/avb5 signaling module initiates a cascade leading to tumor cell invasion in both orthotopic and spontaneous pancreatic cancer cell metastasis models in vivo. We have selected matched primary and metastatic pancreatic cell lines, and found that activation or overexpression of EGFR together with ligation of integrin avb5 appears to induce Src activity and downstream signaling leading to increased invasive behavior of these cells. We find that pancreatic cancer cells expressing increased Src kinase activity invade from the primary tumor deep into the host stroma while primary tumors with minimal Src activity remain confined within the tumor parenchyma as measured by intravital multi-photon imaging. In this proposal, we will characterize the mechanism by which EGFR/Src/avb5 signaling promotes invasion and metastasis. We will explore how Src tyrosine phosphorylation of specific substrates influences this invasive behavior. These studies will focus on how Src not only activates the cell migration machinery, but how it promotes the uncoupling of tumor cell adherens junctions. Finally we will explore how pharmacological and/or genetic disruption of this EGFR/avb5/Src signaling module on metastatic pancreatic cancer cells reverses their metastatic phenotype in vivo. In this case, we will evaluate the possible therapeutic relevance of these targets in orthotopic pancreatic cancer models, as well as a genetic model of spontaneous primary and metastatic pancreatic cancer. These studies should provide molecular insight into a signaling cascade that appears to contribute to the invasive behavior of pancreatic carcinoma.