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

• 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
• 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

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.

项目摘要 北美是世界上肾癌发病率最高的地区，其亚型最常见 是透明细胞肾细胞癌（ccRCC）。令人担忧的是，ccRCC的发病率在美国呈上升趋势， 在全球一旦发生转移，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，代谢功能障碍在ccRCC中很常见。 分子分析治疗ccRCC的新疗法可以靶向其失调的代谢途径。的 ccRCC的病因复杂，但主要的危险因素是肥胖。高水平的支链氨基酸 在患有ccRCC和肥胖症的患者的血清中存在BCAA，这表明了潜在的机制联系。 BCAA（亮氨酸、异亮氨酸和缬氨酸）是必需氨基酸，其浓度由 饮食摄入和catabolism。BCAA代谢促进许多不同类型癌症的肿瘤生长， BCAA在ccRCC中的作用尚不清楚。BCAA催化剂主要通过前两种酶发生，BCAA 转氨酶（BCAT）和支链酮酸脱氢酶（BCKDH）。BCKDH是一个 催化限速反应的酶复合物。BCAA催化剂的产物然后被氧化， 在线粒体内产生琥珀酰辅酶A和乙酰辅酶A，其可被TCA循环用于 回补和线粒体呼吸。 我的初步数据表明，支链氨基酸分解代谢酶BCAT 2和BCKDH亚基是 与正常相邻肾组织（NAT）相比，在人ccRCC肿瘤中经常降低。该减小 早在第1期就出现表达，并与总存活率降低有关。此外，BCAA和 它们的分解代谢产物在ccRCC中减少。这些结果表明，BCAA催化剂减少， 在ccRCC早期，有助于ccRCC的积极性。ccRCC可能会降低BCAA代谢， 线粒体呼吸和ROS，因为ccRCC由于大量的线粒体呼吸而对ROS敏感。 可以进行过氧化的细胞内脂质。ccRCC通过降低线粒体呼吸和ROS， 下调参与脂肪酸氧化和氧化磷酸化的基因。我假设 减少BCAA代谢促进ccRCC细胞生长和肿瘤发生，并通过 减少线粒体呼吸和活性氧的产生。目标1将决定如何减少 BCAA催化剂促进体外ccRCC细胞生长。我会用遗传学和药理学的方法 评估BCAA代谢的获得或丧失如何影响ccRCC和永生化肾上皮细胞的增殖 细胞系目的2将确定减少的BCAA催化剂如何有助于体内ccRCC肿瘤发生。我会 使用新的遗传小鼠模型来确定BCAA分解代谢通量对肾上皮细胞功能的作用 和ccRCC肿瘤发生。总之，这些方法将确定BCAA的机制， catalysts调节ccRCC肿瘤发生，并确定新的治疗靶点来对抗这种疾病。