Tumor cell and microenvironment changes causing antiangiogenic therapy resistance

描述（由申请人提供）：抗血管生成疗法对恶性肿瘤（如胶质母细胞瘤（GBM））的治疗有很大的希望，胶质母细胞瘤是一种毁灭性的脑癌，迫切需要有效的治疗方法。基于令人鼓舞的临床试验结果，2009年，抗血管生成VEGF中和抗体贝伐单抗成为过去四十年来FDA批准的第三种GBM治疗方法。然而，虽然抗血管生成治疗的初始反应通常是显著的，但这些药物的反应持续时间有限。许多肿瘤在最初反应后，发展为获得性侵袭性抗性，这是一种预后不良的快速进展状态。小鼠模型表明，抗血管生成治疗的耐药性可能反映了比传统化疗耐药性通常产生的突变更容易产生的转录或翻译变化。本申请的目的是研究侵入性抗血管生成治疗抗性由上调的受体酪氨酸激酶c-Met和β 1整联蛋白之间的相互作用介导的假设，并且靶向这两种因子或其上游调节因子可以预防或克服治疗抗性。我们将在以下具体目的内研究这一假说：目的1 -确定趋化性c-Met和趋触性β 1整联蛋白在抗血管生成治疗后上调的机制;目的2 -检查c-Met和β 1整联蛋白相互作用以促进对抗血管生成治疗有抗性的肿瘤的侵袭和生长的机制;和目的3 -研究在抗血管生成治疗期间或获得性抗性之后破坏c-Met和β 1整联蛋白或其调节剂对肿瘤的体内侵入性生长的影响。我们将使用我的实验室开发的独特工具和创新来进行这些研究，包括抗血管生成治疗耐药性的新型体内模型和光漂白后荧光恢复（FRAP）的创新应用，以将整合素的流动性和局部粘连中的营业额与耐药性相关联。该项目的成功完成可以（1）确定VEGF对肿瘤侵袭的影响;（2）确定抗血管生成治疗耐药的中心机制，这也将帮助我们了解肿瘤如何适应缺氧;（3）确定靶向抗血管生成治疗侵袭性耐药的药物。因此，我们期望这些研究通过揭示长期断流或VEGF阻断的不良反应来深入了解抗血管生成治疗的双刃剑，并最终使抗血管生成治疗实现其巨大的治疗前景。

DESCRIPTION (provided by applicant): Anti-angiogenic therapy holds much promise for the treatment of malignancies like glioblastoma (GBM), a devastating brain cancer for which effective treatments are badly needed. Based on encouraging clinical trial results, in 2009, the anti-angiogenic VEGF-neutralizing antibody bevacizumab became just the third FDA-approved treatment for GBM in the past four decades. However, while the initial responses to anti-angiogenic therapy are often significant, these agents have had limited durations of response. Many tumors, after responding initially, develop acquired invasive resistance, a rapidly progressive state with a poor prognosis. Mouse models suggest that resistance to anti-angiogenic therapy likely reflects transcriptional or translational changes that are more readily generated than the mutations that typically arise with traditional chemotherapy resistance. The goal of this application is to investigate the hypothesis that invasive anti-angiogenic therapy resistance is mediated by an interaction between upregulated receptor tyrosine kinase c-Met and ß1 integrin, and that targeting these two factors or their upstream regulators can prevent or overcome therapeutic resistance. We will investigate this hypothesis within the following Specific Aims: Aim 1 - Determine the mechanisms by which chemotactic c-Met and haptotactic ß1 integrin are upregulated following anti-angiogenic therapy; Aim 2 - Examine the mechanisms by which c-Met and ß1 integrin interact to promote invasion and growth of tumors resistant to anti-angiogenic therapy; and Aim 3 - Investigate the impact of disrupting c-Met and ß1 integrin or their regulators on the in vivo invasive growth of tumors during anti-angiogenic therapy or after acquired resistance. We will carry out these studies using unique tools and innovations developed in my lab, including novel in vivo models of anti-angiogenic therapy resistance and an innovative application of fluorescence recovery after photobleaching (FRAP) to correlate integrin mobility and turnover in focal adhesions with drug resistance. Successful completion of this project could (1) define the effects of VEGF on tumor invasion; (2) define central mechanisms of resistance to anti-angiogenic therapy, which would also help us understand how tumors adapt to hypoxia in general; and (3) identify agents targeting invasive resistance to anti-angiogenic therapy. Therefore, we expect these studies to offer insight into the double-edged sword of anti-angiogenic therapy by revealing adverse effects of prolonged devascularization or VEGF blockade, and could ultimately allow anti-angiogenic therapy to fulfill its tremendous therapeutic promise.