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Investigating the Role of Reduced Branched-Chain Amino Acid Catabolism in Clear Cell Renal Cell Carcinoma

研究支链氨基酸分解代谢减少在透明细胞肾细胞癌中的作用

基本信息

批准号：
10464235
负责人：
Nathan Jackson Coffey
金额：
$ 5.18万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10464235
关键词：
Accounting Acetyl Coenzyme A Acetylcysteine Acute Affect Albumins Animals Antioxidants Apoptosis Appearance Blood Urea Nitrogen Branched-Chain Amino Acids Catabolism Cell Line Cell Proliferation Cell physiology Cells Citric Acid Cycle Clear Cell Clear cell renal cell carcinoma Coenzyme A Complex Creatinine Data Dietary intake Disease Enzymes Epithelial Cells Essential Amino Acids Etiology Fatty Acids Genes Genetic Genetically Engineered Mouse Glycogen Histologic Histology Human Impairment Implant In Vitro Incidence Isoleucine Isotopes Keto Acids Kidney Leucine Link Lipid Peroxidation Lipids Malignant Epithelial Cell Malignant Neoplasms Measurement Measures Metabolic Metabolic Pathway Metabolic dysfunction Metabolism Mitochondria Molecular Analysis Monitor Multienzyme Complexes Mus NIH-III Mouse North America Nude Mice Obesity Oxidative Phosphorylation Oxides Oxidoreductase Oxygen Consumption Pathway interactions Patients Pharmacology Phosphotransferases Production Prognosis Reaction Reactive Oxygen Species Renal carcinoma Renal function Resected Respiration Risk Factors Role Serum Survival Rate Tamoxifen Testing Tissues Transaminases Tumor Volume Valine Work Xenograft procedure amino acid metabolism base branched-chain-amino-acid transaminase cancer type cell growth combat experimental study fatty acid oxidation gain of function in vivo knock-down loss of function mouse model new therapeutic target novel novel therapeutics peroxidation protein complex renal epithelium small hairpin RNA succinyl-coenzyme A treatment strategy tumor tumor growth tumorigenesis

项目摘要

PROJECT SUMMARY North America has the highest incidence of renal cancer in the world with the most common subtype being clear cell renal cell carcinoma (ccRCC). Alarmingly, the incidence of ccRCC is on the rise in the U.S. and globally. The overall five-year survival rate for ccRCC is only 10-12% once it becomes metastatic, demonstrating the need for new therapies. Metabolic dysfunction is common in ccRCC based on histologic and molecular analysis. New therapies to treat ccRCC could target its dysregulated metabolic pathways. The etiology of ccRCC is complex but a major risk factor is obesity. High levels of branched-chain amino acids (BCAAs) are present in the serum of patients with ccRCC and obesity, suggesting a potential mechanistic link. BCAAs (leucine, isoleucine, and valine) are essential amino acids, whose concentrations are regulated by dietary intake and catabolism. BCAA metabolism promotes tumor growth in many different types of cancer, but the role of BCAAs in ccRCC is unknown. BCAA catabolism occurs primarily via the first two enzymes, BCAA transaminase (BCAT) and branched chain ketoacid dehydrogenase (BCKDH), respectively. BCKDH is an enzyme complex that catalyzes the rate-limiting reaction. The products of BCAA catabolism are then oxidized within the mitochondria to produce succinyl-CoA and acetyl-CoA, which can be used by the TCA cycle for anaplerosis and mitochondrial respiration. My preliminary data demonstrate that BCAA catabolic enzyme BCAT2 and BCKDH subunits are frequently reduced in human ccRCC tumors compared to normal adjacent kidney tissue (NAT). This decreased expression occurs as early as stage 1 and is associated with reduced overall survival. Additionally, BCAAs and their catabolic metabolites are decreased in ccRCC. These results suggest that BCAA catabolism is reduced early in ccRCC and contributes to ccRCC aggressiveness. ccRCC may reduce BCAA metabolism to decrease mitochondrial respiration and ROS because ccRCC is susceptible to ROS due to the large amount of intracellular lipids that can undergo peroxidation. ccRCC decreases mitochondrial respiration and ROS by downregulating genes involved in fatty acid oxidation and oxidative phosphorylation. I hypothesize that reduced BCAA metabolism promotes ccRCC cell growth and tumorigenesis, and does so by decreasing mitochondrial respiration and the production of ROS. Aim 1 will determine how reduced BCAA catabolism promotes ccRCC cell growth in vitro. I will use genetic and pharmacologic approaches to assess how gain or loss of BCAA metabolism affects proliferation of ccRCC and immortalized renal epithelial cell lines. Aim 2 will identify how reduced BCAA catabolism contributes to ccRCC tumorigenesis in vivo. I will use novel genetic mouse models to determine the role of BCAA catabolic flux on renal epithelial cell function and ccRCC tumorigenesis. Together, these approaches will identify the mechanisms by which BCAA catabolism regulates ccRCC tumorigenesis and identify novel therapeutic targets to combat this disease.

项目概要北美是世界上肾癌发病率最高的地区，肾癌亚型最常见透明细胞肾细胞癌（ccRCC）。令人担忧的是，ccRCC 的发病率在美国呈上升趋势，全球。一旦发生转移，ccRCC 的总体五年生存率仅为 10-12%，证明了对新疗法的需求。根据组织学和病理学特征，代谢功能障碍在 ccRCC 中很常见分子分析。治疗 ccRCC 的新疗法可以针对其失调的代谢途径。这 ccRCC 的病因很复杂，但主要危险因素是肥胖。高含量的支链氨基酸 (BCAA) 存在于 ccRCC 和肥胖患者的血清中，表明存在潜在的机制联系。 BCAA（亮氨酸、异亮氨酸和缬氨酸）是必需氨基酸，其浓度受饮食摄入和分解代谢。 BCAA 代谢促进许多不同类型癌症的肿瘤生长，但是 BCAA 在 ccRCC 中的作用尚不清楚。 BCAA 分解代谢主要通过前两种酶 BCAA 发生分别是转氨酶（BCAT）和支链酮酸脱氢酶（BCKDH）。 BCKDH 是一种催化限速反应的酶复合物。支链氨基酸分解代谢的产物随后被氧化在线粒体内产生琥珀酰辅酶A和乙酰辅酶A，可被TCA循环用于回补和线粒体呼吸。我的初步数据表明 BCAA 分解代谢酶 BCAT2 和 BCKDH 亚基是与正常邻近肾组织 (NAT) 相比，人类 ccRCC 肿瘤中的 TNF-α 经常减少。这减少了表达早在第 1 阶段就发生，并与总生存率降低相关。此外，BCAA 和它们的分解代谢物在 ccRCC 中减少。这些结果表明 BCAA 分解代谢减少 ccRCC 早期，有助于 ccRCC 的攻击性。 ccRCC 可能会降低 BCAA 代谢从而降低线粒体呼吸和 ROS，因为 ccRCC 由于存在大量的 ROS，因此很容易受到 ROS 的影响细胞内脂质可发生过氧化反应。 ccRCC 通过以下方式降低线粒体呼吸和 ROS 下调参与脂肪酸氧化和氧化磷酸化的基因。我假设 BCAA 代谢减少可促进 ccRCC 细胞生长和肿瘤发生，其作用机制是减少线粒体呼吸和 ROS 的产生。目标 1 将确定如何减少 BCAA 分解代谢促进 ccRCC 细胞体外生长。我将使用遗传和药理学方法评估 BCAA 代谢的增加或减少如何影响 ccRCC 和永生化肾上皮的增殖细胞系。目标 2 将确定 BCAA 分解代谢减少如何促进体内 ccRCC 肿瘤发生。我会使用新型遗传小鼠模型来确定 BCAA 分解代谢流对肾上皮细胞功能的作用和 ccRCC 肿瘤发生。这些方法将共同确定 BCAA 的机制分解代谢调节 ccRCC 肿瘤发生并确定对抗这种疾病的新治疗靶点。