Tumor Suppressing Pathways in Kidney Cancer

肾癌的肿瘤抑制途径

• 批准号: 10166749
• 负责人: Maria F Czyzyk-Krzeska
• 金额: --
• 依托单位: CINCINNATI VA MEDICAL CENTER RESEARCH
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10166749
• 关键词: Adaptor Signaling Protein; Adult; Age-Years; Amino Acid Sequence; Amino Acids; Autophagocytosis; Autophagosome; C-terminal; Cell Survival; Cell physiology; Cells; Cessation of life; Chloroquine; Clear cell renal cell carcinoma; Combined Modality Therapy; Data; Databases; Degradation Pathway; Enzymes; Epidemiology; Female; Funding; G6PD gene; Gene Expression; Generations; Genetic; Genomics; Glucosephosphate Dehydrogenase; Glutathione; Growth; Health; Human; Hypoxia; Incidence; Investigation; Kidney; LIGHT protein; Laboratory Study; Life; Lipids; Lysosomes; Malignant Neoplasms; Mediating; Medical; Membrane; Messenger RNA; Metabolic Pathway; Microtubule-Associated Proteins; Military Personnel; Modeling; Molecular; NADP; Nucleic Acids; Nutrient; Oncogenic; Organelles; Outcome; Oxidative Stress; Pathway interactions; Pentosephosphate Pathway; Peptides; Persons; Production; Proteins; Publishing; Purines; Regulation; Relative Risks; Renal carcinoma; Reporting; Resistance; Ribose; Risk; Role; Smoke; Smoker; Smoking; Source; Specificity; Specimen; The Cancer Genome Atlas; Transketolase; Tumor Suppressor Proteins; VHL protein; Vacuole; Veterans; Work; Xenograft Model; base; cancer therapy; cell growth; cigarette smoke; cigarette smoking; enzyme pathway; inhibitor/antagonist; knock-down; male; member; metabolomics; non-smoker; novel; paralogous gene; programs; public health relevance; small molecule inhibitor; therapeutic development; transcription factor; tumor; tumor growth; tumor xenograft

 DESCRIPTION (provided by applicant): Clear cell renal cell carcinoma (ccRCC) is a serious health concern for military personnel, particularly males beyond 40 years of age, including military veterans. According to The Defense Medical Epidemiology Database for 1995-2004 the incidence of RCC specifically for military members after the 4th decade of life is dramatically increased to 8.5 as compared to 1.5 cases per 100,000 person-years of the overall incidence. Our laboratory studies molecular pathways regulated by the von Hippel-Lindau (VHL) protein, the most frequently lost tumor suppressor in ccRCC. During the previous funding period we have published important data regarding the role of autophagy in growth of ccRCC. This competitive renewal builds on these substantial observations. Autophagy is a homeostatic function by which cells process their own organelles and proteins in order to eliminate defective molecules and to recycle nutrients. During tumor growth many cancers become addicted to autophagy as a source of nutrients. Moreover, autophagy is activated by different cancer therapies, causing resistance to treatments, and promoting use of autophagic inhibitors, chloroquine derivatives in combination therapies. MAP1LC3s (LC3) are essential proteins for the formation of an autophagosome. In our recently published work and preliminary results, we show that two LC3 paralogs, LC3B and LC3C, have opposite effects on growth of ccRCC. LC3B-dependent autophagy promoted growth of tumors formed by RCC cells with lost VHL, while LC3C-dependent autophagy was tumor suppressive and absent in VHL(-) cells. This proposal focuses on investigations to understand the activity of LC3C-dependent autophagy. Most importantly, we found that LC3C, but not LC3B, autophagic program targets of degradation enzymes of oxidative (rate limiting enzyme, glucose 6-phosphate dehydrogenase, G6PD) and non-oxidative (transketolase, TKT) pentose phosphate pathway (PPP). The effect of LC3C is specific for PPP and does not affect the glycolytic pathway. This important cancer pathway produces ribose-5-phophate for the production of nucleic acids and NADPH for the lipid synthesis and reduction of glutathione, all resulting in enhanced cell survival and growth. The importance of our data is further supported by unsupervised analysis published by KIRC TCGA, which showed significant correlation between levels of G6PD, TKT and poor outcome in ccRCC. The leading hypothesis for this proposal is that loss of VHL through indction of HIF reduces LC3C, permitting activation of PPP to support tumor growth. In Aim 1 we will determine the molecular mechanism by which VHL induces LC3C gene expression. Our working hypothesis is that HIF suppresses LC3C by inducing expression of repressing transcription factors. In Aim 2 we will determine the role of LC3C in the activities of the oxidative and non-oxidative branches of PPP in controlling nucleic acid synthesis and generation of NADPH using genetic and metabolomics approaches. In Aim 3 we will determine the role of the oxidative and non-oxidative branches of PPP in orthotopic xenograft tumor growth and expression of PPP enzymes in human kidney-ccRCC specimens. In Aim 4 we will determine the molecular mechanism by which LC3C, but not LC3B, specifically targets TKT and G6PD for autophagic degradation. Our working hypothesis, supported by preliminary data is that the specificity of LC3C effects is mediated by the LC3C C-terminal peptide.

 描述（由申请人提供）： 透明细胞肾细胞癌 (ccRCC) 是军事人员的严重健康问题，特别是 40 岁以上的男性，包括退伍军人。根据 1995-2004 年国防医学流行病学数据库，军事人员 40 岁以后的 RCC 发病率急剧上升至 8.5 例，而总体发病率每 10 万人年有 1.5 例。我们的实验室研究 von Hippel-Lindau (VHL) 蛋白调节的分子通路，VHL 蛋白是 ccRCC 中最常丢失的肿瘤抑制因子。在之前的资助期间，我们发表了有关自噬在 ccRCC 生长中的作用的重要数据。这种竞争性的更新建立在这些实质性观察的基础上。自噬是一种稳态功能，细胞通过该功能处理自己的细胞器和蛋白质，以消除有缺陷的分子并回收营养物质。在肿瘤生长过程中，许多癌症开始依赖自噬作为营养来源。此外，不同的癌症疗法会激活自噬，导致治疗耐药，并促进自噬抑制剂、氯喹衍生物在联合疗法中的使用。 MAP1LC3 (LC3) 是自噬体形成所必需的蛋白质。在我们最近发表的工作和初步结果中，我们表明两种 LC3 旁系同源物 LC3B 和 LC3C 对 ccRCC 的生长具有相反的影响。 LC3B依赖性自噬促进了VHL缺失的RCC细胞形成的肿瘤的生长，而LC3C依赖性自噬具有肿瘤抑制作用并且在VHL(-)细胞中不存在。该提案的重点是研究了解 LC3C 依赖性自噬的活动。最重要的是，我们发现自噬程序的目标是氧化性（限速酶、葡萄糖6-磷酸脱氢酶、G6PD）和非氧化性（转酮酶、TKT）戊糖磷酸途径（PPP）的降解酶，LC3C（而非LC3B）。 LC3C 的作用是针对 PPP 的，不会影响糖酵解途径。这一重要的癌症途径产生用于生产核酸的 5-磷酸核糖，以及用于脂质合成和谷胱甘肽还原的 NADPH，所有这些都会增强细胞的存活和生长。 KIRC TCGA 发表的无监督分析进一步支持了我们数据的重要性，该分析显示 G6PD、TKT 水平与 ccRCC 不良预后之间存在显着相关性。该提议的主要假设是，通过 HIF 诱导导致 VHL 的损失减少了 LC3C，从而允许激活 PPP 以支持肿瘤生长。在目标 1 中，我们将确定 VHL 诱导 LC3C 基因表达的分子机制。我们的工作假设是 HIF 通过诱导抑制转录因子的表达来抑制 LC3C。在目标 2 中，我们将使用遗传和代谢组学方法确定 LC3C 在 PPP 氧化和非氧化分支活性中的作用，以控制核酸合成和 NADPH 的产生。在目标 3 中，我们将确定 PPP 的氧化和非氧化分支在原位异种移植肿瘤生长和人肾 ccRCC 标本中 PPP 酶表达中的作用。在目标 4 中，我们将确定 LC3C（而非 LC3B）特异性靶向 TKT 和 G6PD 进行自噬降解的分子机制。我们的工作假设（得到初步数据的支持）是 LC3C 效应的特异性是由 LC3C C 末端肽介导的。