Role of Focal Adhesion Kinase In Tumorigenesis

描述（由申请人提供）：本提案的总体目标是了解粘着斑激酶（FAK）在促进肿瘤进展中的作用。许多实验室的工作已经确定FAK是一种重要的细胞内酪氨酸激酶，由整合素和生长因子受体激活。在许多晚期和转移性肿瘤中，FAK过度表达，具有催化活性，并且高度酪氨酸磷酸化。FAK也在肿瘤相关内皮细胞（EC）中被激活。尽管FAK的小分子抑制剂具有抗肿瘤活性，但肿瘤或基质细胞之间的抑制剂作用靶点仍不清楚。在上一个资助期，我们发现乳腺癌细胞内的FAK催化活性通过促进蛋白酶和血管内皮生长因子的表达来增强肿瘤生长和转移。在这里，我们将建立在这些研究，并将测试是否FAK活性的抑制选择性肿瘤细胞，间质内皮细胞，或两者将影响乳腺癌或卵巢癌肿瘤的进展。我们的提议将结合联合收割机遗传学（shRNA敲除和FAK或FAK相关激酶Pyk 2再表达）、药理学（FAK和/或FAK/Pyk 2的小分子抑制剂）和同基因小鼠模型，其并入激酶死亡FAK敲入突变和EC内FAK的诱导性条件性敲除，i-EC-FAK-KO。目的1和2将确定阻断肿瘤或间质中的FAK信号传导是否会影响在完全免疫活性小鼠内的天然微环境中原位植入乳腺癌或卵巢癌细胞后的肿瘤生长或自发转移。这些研究将是第一个测试EC内FAK信号传导作为肿瘤进展潜在贡献者的作用的研究。目的-3将建立在我们发现FAK可以通过一种新的FAK激酶非依赖性机制促进细胞存活的研究基础上，该机制涉及FAK核定位在预防p53肿瘤抑制因子介导的细胞凋亡中。我们将测试FAK和Pyk 2之间是否共享FAK氨基末端FERM结构域的核靶向和p53结合特性，以及FAK是否可以以激酶非依赖性方式发挥作用，通过改变细胞存活率或增加对顺铂的耐药性来促进p53野生型卵巢癌肿瘤进展。这一目标将产生FAK作为衔接蛋白与FAK作为信号激酶相比的潜在差异的关键信息。这些目标的完成将产生对FAK功能的重要见解，并将有助于控制肿瘤细胞生长和扩散的策略的发展。公共卫生相关性：肿瘤细胞不会孤立地发展为恶性肿瘤-肿瘤的微环境可以增强或抑制肿瘤的生长和进展。我们正在研究黏着斑激酶（FAK）信号传导如何通过影响肿瘤微环境的激酶依赖性和独立机制促进肿瘤进展的分子机制。这些研究将填补我们对调节肿瘤生长和扩散的整合素相关信号事件理解的关键空白。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand the role of focal adhesion kinase (FAK) in promoting tumor progression. Work from a number of labs has identified FAK as an important intracellular tyrosine kinase activated by integrins and growth factor receptors. In many advanced and metastatic tumors, FAK is over-expressed, catalytically-active, and highly tyrosine phosphorylated. FAK is activated also in tumor-associated endothelial cells (ECs). Although a small molecule inhibitor to FAK has anti-tumor activity, targets of inhibitor action between tumor or stromal cells remain unclear. In the last funding period, we showed that FAK catalytic activity within breast carcinoma cells enhances tumor growth and metastasis by promoting protease and vascular endothelial growth factor expression. Here, we will build upon these studies and will test whether the inhibition of FAK activity selectively within tumor cells, stromal ECs, or both will affect breast or ovarian carcinoma tumor progression. Our proposal will combine genetic (shRNA knockdown and FAK or FAK-related kinase Pyk2 re-expression), pharmacological (small molecular inhibitors to FAK and/or FAK/Pyk2), and syngeneic mouse models incorporating a kinase-dead FAK knock-in mutation and the inducible conditional knockout of FAK within ECs, i-EC-FAK-KO. Aims 1 and 2 will determine whether blocking FAK signaling in tumor or stroma will affect either tumor growth or spontaneous metastasis after orthotopic implantation of breast or ovarian carcinoma cells in a native microenvironment within fully immune-competent mice. These studies will be the first to test the role of FAK signaling within ECs as a potential contributor to tumor progression. Aim-3 will build upon studies where we found that FAK can promote cell survival through a novel FAK kinase-independent mechanism involving FAK nuclear localization in preventing p53 tumor suppressor- mediated cell apoptosis. We will test whether nuclear targeting and p53 binding properties of the FAK amino-terminal FERM domain are shared between FAK and Pyk2, and whether FAK can function in a kinase-independent manner to promote p53 wildtype ovarian carcinoma tumor progression through alterations in cell survival or increased resistance to cisplatin. This aim will yield key information on potential differences of FAK as an adaptor protein compared to FAK as signaling kinase. Completion of these aims will yield important insights into FAK function and will aid in the development of strategies to control the growth and spread of tumor cells. PUBLIC HEALTH RELEVANCE: Tumor cells do not progress to malignancy in isolation - the microenvironment of the tumor can either enhance or suppress tumor growth and progression. We are investigating the molecular mechanism of how focal adhesion kinase (FAK) signaling facilitates tumor progression through both kinase-dependent and independent mechanisms influencing the tumor microenvironment. These studies will fill key gaps in our understanding of integrin-associated signaling events regulating tumor growth and spread.