The von Hippel-Lindau Tumor Suppressor Gene and Kidney Cancer: Insights into Oxygen Sensing and Treating Cancers Caused by Undruggable Mutations

von Hippel-Lindau 肿瘤抑制基因和肾癌：深入了解氧感应和治疗由不可药物突变引起的癌症

基本信息

批准号：
10737695
负责人：
WILLIAM G. KAELIN
金额：
$ 99.78万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-01 至 2030-08-31
项目状态：
未结题

项目摘要

VHL tumor suppressor protein (pVHL) inactivation is the usual initiating (“truncal”) event in the most common form of kidney cancer, clear cell renal cell carcinoma (ccRCC). pVHL forms a ubiquitin ligase that targets the HIF transcription factor for degradation. HIF2, but not HIF1, promotes ccRCC. Binding to pVHL requires that the HIFalpha subunit be prolyl hydroxylated by one of the 3 oxygen-sensitive EglN prolyl hydroxylases, which are 2-oxoglutarate (2-OG)-dependent dioxygenases (as are the TET DNA demethylases and KDM histone demethylases). IDH mutant cancers accumulate the 2-OG competitor 2-hydroxyglutarate (2-HG). Our work contributed to the development of VEGF inhibitors/HIF2 inhibitors for ccRCC and 2-HG inhibitors for IDH mutant leukemia. Our discovery that thalidomide reprograms cereblon to destroy the IKZF1/3 myeloma oncoproteins has also galvanized interest in small molecule degraders. Not all ccRCCs respond to VEGF inhibitors/HIF2 inhibitors and 2-HG inhibitors are fairly inactive against IDH mutant gliomas. Synthetic lethality (SL) should be a source of alternative drug targets for such tumors, and more generally, for cancers linked to “undruggable” mutations. We have identified new potential SL interactors for VHL (CDK4/6 and ITGAV) and mutant IDH (DHODH and GSK3b) and now propose further validation and mechanistic studies. Intriguingly, Cyclin D1, the partner for CDK4/6, is a HIF2 target in ccRCC, but the SL between VHL and CDK4/6 is not HIF2-dependent. We also embarked on SL screens in Drosophila cells because paralog compensation likely causes many false-negatives in genetic screens with human cells. We created an “up” screen for chemicals and gene knockouts that can degrade a protein of interest. We used it to discover that Spautin-1 is a cereblon-independent IKZF1 degrader and are pursuing the underlying mechanism. We are also applying it to various undruggable oncoproteins (e.g., c-Myc, K-Ras, b-Catenin). Failure to downregulate Cyclin D1 causes resistance of VHL-/- ccRCC to HIF2 inhibitors in a pRB- independent manner. We are using biochemical approaches to identify the relevant Cyclin D1 substrate(s). We unexpectedly found that HIF1 and HIF2 bind to approximately the same genomic sites, yet recruit different proteins. We are validating these associated proteins in biochemical and functional assays. We are also using substrate-trapping conditions to recover non-HIF EglN substrates and non-histone KDM substrates. We are continuing our efforts to use somatic gene editing with CRISPR to make a murine model of HIF2- dependent VHL-/- ccRCC. We have also identified new pVHL-dependent secreted proteins including PTH-LH, which might cause the cachexia and hypercalcemia seen in some ccRCC patients. ccRCC is highly immunogenic, but the reason is unknown. We found that HIF2 drives the expression of many endogenous retroviruses, some of which can be translated and presented as HLA-bound peptides. We are examining additional ccRCC cell lines and tumors for such peptides and whether they are immunogenic.

在最常见的肾癌的形式，透明细胞肾细胞癌（CCRCC）。 PVHL形成一个泛素连接酶，该连接酶针对 HIF转录因子降解。 HIF2，但不是HIF1，促进了CCRCC。与PVHL结合需要 hifalpha亚基是由3种氧气敏感EGLN丙酰羟化酶之一的羟基羟基化的是2-氧基谷物（2-OG）依赖性二氧酶（TET DNA脱甲基酶和KDM组蛋白也是脱甲基酶）。 IDH突变癌积累了2-EOG竞争者2-羟基戊二酸（2-HG）。我们的工作为IDH的CCRCC和2-HG抑制剂的VEGF抑制剂/HIF2抑制剂的开发做出了贡献突变白血病。我们发现，丘里度胺重编程了Cereblon以破坏IKZF1/3骨髓瘤癌蛋白还激发了对小分子降解器的兴趣。并非所有CCRCC都对VEGF抑制剂/HIF2抑制剂和2-HG抑制剂做出反应 IDH突变神经胶质瘤。合成致死性（SL）应该是此类肿瘤的替代药物靶标的来源，并且更一般而言，对于与“不良”突变相关的癌症。我们已经确定了新的潜在SL交互器对于VHL（CDK4/6和ITGAV）和突变体IDH（Dhodh和GSK3B），现在提议进一步验证机械研究。有趣的是，CDK4/6的伙伴Cyclin D1是CCRCC中的HIF2目标，但是SL VHL和CDK4/6之间并非HIF2依赖性。我们还登上了果蝇细胞中的SL屏幕因为旁系同源补偿可能会导致许多人类细胞遗传筛选中的许多假阴性。我们为化学物质和基因敲除可以降解感兴趣的蛋白质的“向上”屏幕。我们用它来发现spautin-1是一个独立于伯隆的ikzf1降解器，正在追求基础机制。我们还将其应用于各种不良的癌蛋白（例如C-Myc，K-Ras，B-catenin）。未能下调细胞周期蛋白D1会导致VHL - / - CCRC对PRB-中HIF2抑制剂的抗性独立的方式。我们正在使用生化方法来识别相关的细胞周期蛋白D1底物。我们意外地发现HIF1和HIF2与大致相同的基因组位点结合，但招募不同的蛋白质。我们正在验证这些相关的蛋白质中的生化和功能测定法。我们是还使用底物捕捞条件来恢复非HIF EGLN底物和非吊杆KDM底物。我们正在继续努力使用CRISPR使用躯体基因编辑来制作HIF2-的鼠模型。依赖的VHL - / - CCRCC。我们还确定了包括PTH-LH，包括PTH-LH的新的PVHL依赖性分泌蛋白这可能会引起一些CCRCC患者的恶病症和高钙血症。 CCRC具有高度免疫原性，但原因尚不清楚。我们发现HIF2驱动了许多内源性逆转录病毒，其中一些可以被翻译成HLA结合的肽。我们正在检查此类辣椒的其他CCRCC细胞系和肿瘤以及它们是否具有免疫原性。