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认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、催化活性和高度酪氨酸磷酸化。FAK在肿瘤相关的内皮细胞(ECs)中也被激活。尽管FAK的小分子抑制剂具有抗肿瘤活性，但肿瘤或间质细胞之间的抑制作用靶点仍不清楚。在上一次资助期间，我们发现乳腺癌细胞内的FAK催化活性通过促进蛋白水解酶和血管内皮生长因子的表达来促进肿瘤的生长和转移。在这里，我们将在这些研究的基础上，测试在肿瘤细胞、间质内皮细胞或两者中选择性地抑制FAK活性是否会影响乳腺癌或卵巢癌的肿瘤进展。我们的建议将结合遗传的(shRNA敲除和FAK或FAK相关的激酶Pyk2重新表达)，药理学的(FAK和/或FAK/Pyk2的小分子抑制剂)，以及同种基因的小鼠模型，整合了激酶死亡的FAK敲入突变和ECs中可诱导的条件敲除FAK，I-EC-FAK-KO。AIMS 1和2将确定阻断肿瘤或间质中的FAK信号是否会影响乳腺或卵巢癌细胞在完全免疫能力的小鼠体内的自然微环境中原位移植后的肿瘤生长或自发转移。这些研究将首次测试内皮细胞内FAK信号作为肿瘤进展的潜在贡献者的作用。AIM-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在阻止p53肿瘤抑制因子介导的细胞凋亡中的核定位。我们将测试FAK氨基末端FERM结构域的核靶向性和P53结合特性是否在FAK和PYK2之间共享，以及FAK是否可以通过改变细胞存活率或增加对顺铂的耐药性而以不依赖于激酶的方式促进P53野生型卵巢癌的进展。这一目标将提供关于FAK作为接头蛋白与FAK作为信号转导蛋白的潜在差异的关键信息。完成这些目标将产生对FAK功能的重要见解，并将有助于制定控制肿瘤细胞生长和扩散的策略。公共卫生相关性：肿瘤细胞不会在孤立的情况下进展为恶性肿瘤--肿瘤的微环境可以促进或抑制肿瘤的生长和进展。我们正在研究粘着斑激酶(FAK)信号如何通过影响肿瘤微环境的激酶依赖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的理解的关键空白。

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.