Targeting Focal Adhesion Kinase in Thyroid Cancer

项目总结 美国至少有30万人患有甲状腺癌，其中1500多人死亡 每年都会死于这种疾病。BRAF、RET/PTC、RAS和PIK3CA的致癌改变在 许多甲状腺癌，以及针对这些途径的靶向治疗正在进行测试。然而，初步试验 在现阶段，以这条途径为目标并不像预期的那样令人印象深刻。因此，至关重要的是进一步 阐明甲状腺癌进展和转移的分子机制及寻找新药 目标。粘着斑激酶(FAK)在多种肿瘤类型中过表达和激活 成为一个有希望的治疗靶点，特别是与转移有关的靶点。FAK是一种多功能的激酶 其活性依赖于Src激酶，在完全激活后，FAK-Src信号复合体调节 多种细胞反应，包括增殖、侵袭和转移。我们最近发现FAK 在甲状腺癌临床样本以及晚期甲状腺癌来源的细胞系中过表达和激活 甲状腺癌患者。我们进一步证明了甲状腺癌细胞的生长和侵袭 表达高水平的磷酸化FAK对Src抑制剂Saracatinib， 用来抑制FAK功能。值得注意的是，激活的Src水平与Src抑制物没有相关性 敏感性，提示FAK是该通路中致癌信号的关键介导者。最近，特工们 靶向FAK已经进入临床试验，提供了第一次直接靶向FAK激酶活性的机会 FAK。FAK在甲状腺癌生长、侵袭和转移中的具体作用尚未得到检验。FAK 起信号转导和支架蛋白的作用，使其作为临床靶点的作用复杂化。我们的 使用药理学和遗传学方法阻断激酶和/或支架功能的初步数据 提示这些双重功能可能调节甲状腺癌不同的细胞过程。这个 本提案的目标是了解FAK作为这些亲-中介者的调节和功能 肿瘤形成过程。在目标1和目标2中，我们将同时使用基因shRNA FAK敲除 用最新开发的FAK抑制剂的药理学方法来确定激酶和 FAK在体外甲状腺癌细胞生长、侵袭和存活中的支架作用(目标1)； 在体内使用了一种新的原位甲状腺癌模型和一种实验性的转移模型，我们 已开发(目标2)。在目标3中，我们将验证FAK信号的临床相关性 甲状腺肿瘤基因芯片。这些目标的成功完成将决定是否抑制FAK 为晚期甲状腺癌患者提供了一种更合理、更特异的治疗方法，并预防 转移癌以及其他带有致癌FAK信号的低分化癌症。

PROJECT SUMMARY At least 300,000 people are living with thyroid cancer in the United States, and more than 1,500 of them die each year from this disease. Oncogenic alterations in BRAF, RET/PTC, RAS, and PIK3CA are common in many thyroid cancers, and targeted therapies against these pathways are being tested. However, initial trials targeting this pathway have not been as impressive as expected at this stage. Thus, it is critical to further elucidate the molecular mechanisms of thyroid cancer progression and metastasis and to identify novel drug targets. Focal Adhesion Kinase (FAK) is overexpressed and activated in numerous tumor types and has emerged as a promising therapeutic target, especially in relation to metastasis. FAK is a multifunctional kinase whose activity is dependent on Src kinase and upon full activation the FAK-Src signaling complex regulates multiple cellular responses including proliferation, invasion, and metastasis. We recently discovered that FAK is overexpressed and activated in thyroid cancer clinical samples as well as cell lines derived from advanced thyroid cancer patients. We further demonstrated that the growth and invasion of thyroid cancer cells expressing high levels of phosphorylated FAK are susceptible to treatment with the Src inhibitor, saracatinib, which was used to inhibit FAK function. Notably, levels of activated Src did not correlate with Src inhibitor sensitivity, suggesting that FAK is the key mediator of oncogenic signaling in this pathway. Recently, agents targeting FAK have entered clinical trials, providing the first opportunity to directly target the kinase activity of FAK. The specific role of FAK in thyroid cancer growth, invasion, and metastasis has not been tested. FAK functions as a signaling kinase and a scaffolding protein, complicating its role as a clinical target. Our preliminary data using pharmacologic and genetic approaches to block the kinase and/or scaffolding functions of FAK, suggest that these dual functions may regulate different cellular processes in thyroid cancer. The goals of this proposal are to understand the regulation and function of FAK as a central mediator of these pro- tumorigenic processes. In Aims 1 and 2, we will use genetic shRNA FAK knockdown in parallel with pharmacologic approaches with recently developed FAK inhibitors to define the specific role of the kinase and scaffolding functions of FAK in the growth, invasion, and survival of thyroid cancer cells in vitro (Aim 1); as well as in vivo using a novel orthotopic thyroid cancer model and an experimental metastasis model, which we developed (Aim 2). In Aim 3, we will validate the clinical relevance of FAK signaling using a comprehensive thyroid tumor microarray. Successful completion of these aims will determine whether inhibition of FAK represents a rational and more specific therapy for patients with advanced thyroid cancer and the prevention of metastases as well as other poorly differentiated cancers with oncogenic FAK signaling.