Regulation of the Kidney Cancer Epigenome by Oncometabolite L-2-Hydroxyglutarate

项目摘要。肾细胞癌（RCC）是男性和女性最常见的10种恶性肿瘤之一 和妇女不幸的是，晚期疾病患者的治疗进展缓慢， 新的治疗方法是必要的。新陈代谢改变，恶性肿瘤的标志， 可能提供新的治疗机会。肿瘤，小分子，具有假定的转化 这些特性代表了新陈代谢和癌症之间最明显的联系之一。一个统一的主题， 迄今为止鉴定出的致癌物是它们通过抑制参与肿瘤形成的酶来改变表观基因组的能力。 DNA和组蛋白去甲基化。在区域合作理事会方面，人们日益认识到 表观遗传学与这种恶性肿瘤的发病机制有关。然而，RCC表观基因组的驱动因素仍然存在， 特征不佳。我们实验室的长期目标是了解代谢在肾脏疾病中的作用。 癌症的发生，以开发新的治疗方法，将改善结果。这项建议的目的是 确定RCC表观遗传景观的代谢基础，并确定对肿瘤发生的影响。 我们实验室和其他实验室的研究已经确定了假定的癌代谢物（L）-2- 羟基戊二酸（L-2HG）在RCC以及脑肿瘤中的作用。RCC中L-2HG的升高是由于 表达位于染色体14 q上的L2 HGDH（L-2HG脱氢酶）。有趣的是，14q损失是 与肾细胞癌的DNA高甲基化表型、耐药性和恶化的预后相关 患者该提议的中心假设是L-2HG是一种强大的表观遗传修饰剂， 肾癌的恶性表型。这一假设是基于强有力的初步数据表明，重新- RCC细胞中L2HGDH的表达（并因此降低细胞L-2HG水平）可以逆转表观遗传 修饰和抑制体外和体内肿瘤表型。此外，高L-2HG肿瘤 来自患者的样本显示RCC高甲基化表型。在目标1中，我们将剖析基因， 导致L-2HG积累的生化事件。在目标2中，我们将确定L-2HG对 超甲基化表型，并评估对基因表达的影响，利用的方法包括 下一代测序与甲基化阵列。在目标3中，我们将确定 L2HGDH抑制肿瘤生长。此外，我们将评估L2HGDH缺失在肿瘤发生中的作用， 使用新的遗传模型的进展。这项拟议中的研究意义重大，因为它将确定 RCC表观基因组在靶向途径背景下的驱动因素。这种方法是创新的，因为它 将在RCC的表观基因组和肿瘤代谢之间建立联系。最终，知识 聚集有可能提高晚期RCC患者的治疗效果，这是一个未满足的需求。 挑战着当代对这种疾病的管理。

PROJECT SUMMARY. Renal cell carcinoma (RCC) is among the 10 most common malignancies in both men and women. Unfortunately, progress in the treatment of patients with advanced disease has been incremental, and new treatment approaches are warranted. Altered metabolism, an established hallmark of malignancy, may provide novel therapeutic opportunities. Oncometabolites, small molecules with putative transforming properties, represent one of the clearest links between metabolism and cancer. A unifying theme amongst the oncometabolites identified to date is their ability to alter the epigenome via inhibition of enzymes involved in DNA and histone demethylation. In the context of RCC, there is increasing recognition of the role of epigenetics to the pathogenesis of this malignancy. However, the drivers of the RCC epigenome remain poorly characterized. The long-term goal of our laboratory is to understand the role of metabolism in renal carcinogenesis to develop novel therapies that will improve outcomes. The objective of this proposal is to identify the metabolic basis for the epigenetic landscape of RCC and to determine the effects on tumorigenesis. Studies by our laboratory and others have identified elevations of the putative oncometabolite (L)-2- hydroxyglutarate (L-2HG) in RCC as well as brain tumors. Elevations of L-2HG in RCC are due to reduced expression of L2HGDH (L-2HG dehydrogenase) which is located on chromosome 14q. Intriguingly, 14q loss is associated with a DNA hypermethylation phenotype, therapy resistance, and worsened outcomes in RCC patients. The central hypothesis of this proposal is that L-2HG is a powerful epigenetic modifier that drives the malignant phenotype of RCC. This hypothesis is based on strong preliminary data demonstrating that re- expression of L2HGDH in RCC cells (and thus lowering of cellular L-2HG levels) can reverse epigenetic modifications and suppresses both in vitro and in vivo tumor phenotypes. Additionally, high L-2HG tumors from patients demonstrate a RCC hypermethylator phenotype. In Aim 1, we will dissect the genetic and biochemical events that lead to L-2HG accumulation. In Aim 2, we will determine the contribution of L-2HG to the hypermethylator phenotype and assess the effects on gene expression utilizing methodologies including next generation sequencing with methylome array. In Aim 3, we will determine the mechanism by which L2HGDH suppresses tumor growth. In addition, we will assess the role of L2HGDH loss in tumor initiation and progression using novel genetic models. The proposed research is significant because it will identify the drivers of the RCC epigenome in the context of targetable pathways. The approach is innovative because it will establish a link between the epigenome and tumor metabolism in RCC. Ultimately, the knowledge gathered has the potential to improve the efficacy of treatment for patients with advanced RCC, an unmet need challenging the contemporary management of this disease.