Targeting the heat shock response for the therapy of DLBCL

描述(由申请人提供)： 我们的建议探讨了弥漫性大B细胞淋巴瘤(DLBCL)的分子发病机制和治疗靶向，这是最常见的非霍奇金淋巴瘤形式。由于这些肿瘤具有明显的异质性，我们有兴趣确定与DLBCL患者尽可能广泛的横切面相关的机制。最近的一项研究表明，热休克蛋白90(Hsp90)在DLBCL中广泛表达。我们独立地证实和验证了这一结果，并表明Hsp90结合并防止BCL6转录抑制物和IKK复合体的Nemo亚单位降解，这两个亚单位都是DLBCL致癌途径的组成部分。有几个小组已经开发出Hsp90抑制剂。然而，这些分子中的大多数具有相对较窄的治疗窗口，这使得在体内不可能完全抑制肿瘤Hsp90。Chisis实验室开发了一种名为PUH71的Hsp90嘌呤支架抑制剂。与其他Hsp90抑制剂相比，PUH71更有效和更特异地结合Hsp90的一部分，该部分伴随肿瘤细胞内的致癌客户蛋白，并在体外和体内容易杀死DLBCL细胞。在治疗水平上，一次给小鼠注射的PUH71在淋巴瘤中保持了48小时以上，但在短短几个小时内就从正常组织中迅速清除。因此，与其他Hsp90抑制剂相比，PUH71显示出更宽的治疗窗口，因此具有更强的抗DLBCL效果。鉴于这些有希望的结果，国家癌症研究所癌症治疗和诊断部正在赞助PUH71的翻译，用于临床试验。综上所述，我们的初步机制和临床前数据使我们假设Hsp90在广泛的DLBCL中是一个关键的治疗靶点，DLBCL对Hsp90上瘾是因为它保护DLBCL不同亚型中参与DLBCL生存的多个途径的降解成分。鉴于其优越的药理学特性，我们预测PUH71将是一种在原发人类DLBCL中高度活跃的药物，并将与针对互补生物途径的抗淋巴瘤药物协同作用。目前的建议将利用PUH71独特的生化特性，并将其作为诱饵，在蛋白质组学分析中鉴定DLBCL中致癌的Hsp90客户蛋白，并结合功能验证研究。第二种方法将探索一系列原始人类DLBCL对PUH71的反应，并使用表达谱和生物信息学工具来识别导致DLBCL生物依赖于Hsp90的基因途径。然后，我们将利用这些信息来设计治疗DLBCL的联合靶向治疗方案。这项建议将提供有关Hsp90在淋巴瘤中功能的机制信息，也将提供新的治疗方案和生物标记物用于DLBCL患者的测试。 公共卫生相关性： B细胞淋巴瘤是美国第四种最常见的癌症，这种疾病的几种亚型是无法治愈的；尽管从分子角度来看，这些肿瘤具有明显的异质性，但它们中的许多似乎都表达并需要Hsp90伴侣蛋白的存在。我们最近开发了一种名为PUH71的Hsp90抑制剂，具有优异的药理和生化特性。这项建议将确定Hsp90的致癌客户蛋白，确定对PUH71有反应的淋巴瘤的谱，确定依赖于Hsp90的肿瘤的功能基因组学特征，然后利用这些信息开发以使用PUH71为中心的合理设计的B细胞淋巴瘤联合治疗方案。

DESCRIPTION (provided by applicant): Our proposal explores the molecular pathogenesis and therapeutic targeting of diffuse large B-cell lymphomas (DLBCL), which are the most common form of non-Hodgkin's lymphoma. Since these tumors are markedly heterogeneous, we are interested in identifying mechanisms relevant to the broadest cross-section possible of DLBCL patients. A recent report suggested that heat shock protein 90 (Hsp90) is widely expressed in DLBCL. We independently confirmed and validated this result and showed that Hsp90 binds and protects from degradation the BCL6 transcriptional repressor and the NEMO subunit of the IKK complex, both of which are components of oncogenic pathways in DLBCL. Several groups have developed Hsp90 inhibitors. However, most of these molecules have a relatively narrow therapeutic window that makes it impossible to fully suppress tumor Hsp90 in vivo. The Chiosis laboratory developed a purine scaffold inhibitor of Hsp90 called PUH71. PUH71 more potently and specifically binds the fraction of Hsp90 that chaperones oncogenic client proteins within tumor cells vs. other Hsp90 inhibitors and readily kills DLBCL cells in vitro and in vivo. A single dose of PUH71 administered to mice remained in lymphomas for over 48 hours at therapeutic levels, but rapidly cleared from normal tissues in just a few hours. Accordingly, PUH71 exhibited a wider therapeutic window and thus greater anti-DLBCL efficacy than other Hsp90 inhibitors. Given these promising results, the National Cancer Institute Division of Cancer Treatment and Diagnosis is sponsoring the translation of PUH71 for use in clinical trials. Altogether, our preliminary mechanistic and pre-clinical data lead us to hypothesize that Hsp90 is a critical therapeutic target in a broad cross-section of DLBCLs and that DLBCLs become addicted to Hsp90 since it protects from degradation components of multiple pathways involved in the survival of DLBCL across its various subtypes. Given its superior pharmacologic properties, we predict that PUH71 will be a highly active in primary human DLBCL and will synergize with anti-lymphoma drugs that target complementary biological pathways. The current proposal will take advantage of the unique biochemical properties of PUH71 and use it as a bait to identify oncogenic Hsp90 client proteins in DLBCL in proteomics assays, coupled with functional validation studies. A second approach will explore the response of a spectrum of primary human DLBCLs to PUH71 and use expression profiling and bio-informatic tools to identify gene pathways that contribute to making DLBCLs biologically dependent on Hsp90. We will then use this information to design combinatorial-targeted therapy regimens for the treatment of DLBCL. This proposal will deliver mechanistic information concerning the functions of Hsp90 in lymphomas, and also will deliver new therapeutic regimens and biomarkers for testing in DLBCL patients. PUBLIC HEALTH RELEVANCE: B-cell lymphomas are the fourth most common form of cancer in the United States and several subtypes of this disease are incurable; and although these tumors are markedly heterogeneous from the molecular standpoint, many of them appear to express and require the presence of the Hsp90 chaperone protein. We recently developed an Hsp90 inhibitor called PUH71 with superior pharmacologic and biochemical properties. This proposal will identify the oncogenic client proteins of Hsp90, determine the spectrum of lymphomas that respond to PUH71, identify the functional genomics characteristics of tumors that are Hsp90 dependent, and then use this information to develop rationally designed combinatorial therapy regimens for B-cell lymphomas centered around the use of PUH71.