Targeting Focal Adhesion Kinase in Thyroid Cancer

项目摘要 美国至少有30万人患有甲状腺癌，其中1,500多人死亡 每年都有这种疾病。BRAF、RET/PTC、RAS和PIK 3CA中的致癌性改变常见于 许多甲状腺癌和针对这些途径的靶向疗法正在测试中。然而，初步试验 在现阶段，针对这一途径的工作并没有像预期的那样令人印象深刻。因此，关键是要进一步 阐明甲状腺癌进展和转移的分子机制，并发现新药 目标的粘着斑激酶（FAK）在许多肿瘤类型中过表达和活化， 作为一个有前途的治疗靶点，特别是在转移方面。FAK是一种多功能激酶 其活性依赖于Src激酶，并且在完全活化时，FAK-Src信号传导复合物调节 多种细胞反应，包括增殖、侵袭和转移。我们最近发现FAK 在甲状腺癌临床样品以及来自晚期甲状腺癌的细胞系中过表达和活化。 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 表达高水平磷酸化FAK的人对Src抑制剂，saracatinib， 其用于抑制FAK功能。值得注意的是，活化Src的水平与Src抑制剂无关。 敏感性，表明FAK是该途径中致癌信号传导的关键介质。最近，代理商 靶向FAK的药物已经进入临床试验，提供了第一次直接靶向FAK激酶活性的机会。 假的。FAK在甲状腺癌生长、侵袭和转移中的具体作用尚未得到证实。FAK 作为信号激酶和支架蛋白发挥作用，使其作为临床靶点的作用复杂化。我们 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中不同的细胞过程。的 这项建议的目标是了解FAK作为这些亲- 肿瘤发生过程。在目的1和2中，我们将使用基因shRNA FAK敲低与 最近开发的FAK抑制剂的药理学方法，以确定激酶的具体作用， FAK在体外甲状腺癌细胞生长、侵袭和存活中的支架功能（Aim 1）;以及 在体内使用新的原位甲状腺癌模型和实验转移模型，我们 目标2（Aim 2）在目标3中，我们将使用一个全面的方法来验证FAK信号传导的临床相关性。 甲状腺肿瘤微阵列成功完成这些目标将决定是否抑制FAK 代表了一种合理的和更具体的治疗晚期甲状腺癌患者和预防 转移以及其他具有致癌FAK信号传导的低分化癌症。

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.