Probing mitochondria and personalizing leukemia therapy with BH3 profiling

描述（由申请人提供）：随着越来越多的慢性淋巴细胞白血病（CLL）治疗方法的测试，为每个患者确定哪种治疗方法是最好的挑战越来越大。在这一竞争性更新提案中，我们提出了识别个体CLL肿瘤治疗机会的策略。这种方法的一个关键要素是能够预测患者对个别治疗的反应。我们运用了我们在最初的资助阶段所学到的关于细胞凋亡控制的基本知识，并利用了我们在提案中改进的BH3分析工具。在我们之前的工作中，我们发现我们可以将ABT-737的体外敏感性与BH3分析结果联系起来，我们建议测试我们预测CLL对相关BCL-2拮抗剂ABT-199的临床反应的能力（Specific Aim #1）。此外，在Specific Aim #2中，我们建议确定CLL个体病例中的通路成瘾。过去，在CLL中，siRNA和shRNA方法的低效率和体外培养的困难使得这一问题难以通过常规手段解决。我们提出了一项研究，使用小分子途径抑制剂而不是敲低策略来逃避RNA转染困难。重要的是，我们使用BH3分析来测量药物治疗后4-24小时内的早期凋亡信号，从而避免了延长离体培养的需要。我们的目的是将响应小分子抑制剂的早期凋亡信号与通路成瘾联系起来。该方法的一个重要优势是，检测原发性CLL对药物反应的凋亡信号为临床转化提供了合理的途径。最后，在具体目标#3中，我们

DESCRIPTION (provided by applicant): With the growing number of therapies being tested in chronic lymphocytic leukemia (CLL) comes the growing challenge of identifying for each patient which therapies are the best. In this competitive renewal proposal, we propose strategies to identify therapeutic opportunities in individual CLL tumors. A key element of this approach is the ability to predict patient response to individual therapies. We apply many of the basic lessons we have learned in the initial grant period about control of apoptosis, and make use of a tool that we refined in that proposal, BH3 profiling. Building on our prior work in which we found we can correlate in vitro sensitivity to ABT-737 to BH3 profiling results, we propose to test our ability to predict clinical response to the related BCL-2 antagonist, ABT-199 in CLL (Specific Aim #1). In addition, in Specific Aim #2, we propose to identify pathway addiction in individual cases of CLL. In the past, inefficiency of siRNA and shRNA approaches and difficulty of ex vivo culture in CLL have made this issue difficult to address by conventional means. We propose a study using small molecule pathway inhibitors instead of knockdown strategies to evade RNA transfection difficulties. Importantly, we use BH3 profiling to measure early apoptotic signaling within 4-24 of drug treatment, obviating the need for extended ex vivo culture. Our aim is to link early apoptotic signaling in response to small molecule inhibitors to pathway addiction. An important advantage of this approach is that detection of apoptotic signaling in primary CLL in response to drugs provides a rational path to clinical translation. Finally, in Specific Aim #3, we propose to investigate how stromal interactions inhibit apoptotic signaling in CLL cells. Moreover, using in vitro co-culture systems, we will study the efficacy and mechanisms of drugs intended to interrupt CLL interactions with stromal cells. Our goal is to identify which CLL patients will most benefit from such therapies. PUBLIC HEALTH RELEVANCE: There is a growing number of new and exciting targeted therapies being tested for treating chronic lymphocytic leukemia and other leukemias. However, it is often difficult to predict which patients will benefit most from these therapies, so that thee is a risk of many being treated with drugs that are not useful, and others not getting drugs from which they could benefit. In this proposal, we test a novel strategy, based on our improved understanding of cell death pathways, for matching individual tumors with the drugs that will work best against them to better personalize therapy for chronic lymphocytic leukemia.