Tumor Suppressing Pathways in Kidney Cancer

肾癌的肿瘤抑制途径

• 批准号: 9326809
• 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 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9326809
• 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; Cigarette; Clear Cell; 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 Cell Carcinoma; 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 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) 是军事人员的一个严重健康问题，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，RCC 的发病率特别针对军事人员。与总发病率每 10 万人年 1.5 例相比，第四个十年的发病率急剧增加至 8.5 例。 Hippel-Lindau (VHL) 蛋白是 ccRCC 中最常见的肿瘤抑制蛋白。在上一个资助期间，我们发表了有关自噬在 ccRCC 生长中的作用的重要数据。自噬是一种稳态。细胞通过其处理自身细胞器和蛋白质以消除有缺陷的分子并回收营养物质的功能，在肿瘤生长过程中，许多癌症开始依赖自噬作为营养来源。在我们最近发表的工作和初步结果中，氯喹衍生物被不同的癌症疗法激活，导致治疗耐药，并促进自噬抑制剂的使用。两种 LC3 旁系同源物 LC3B 和 LC3C 对 ccRCC 的生长具有相反的作用，LC3B 依赖性自噬促进了由丢失 VHL 的 RCC 细胞形成的肿瘤的生长。而LC3C依赖性自噬在VHL(-)细胞中具有肿瘤抑制作用并且不存在。最重要的是，我们发现LC3C而非LC3B是了解降解酶的自噬程序目标。氧化（限速酶、葡萄糖 6-磷酸脱氢酶、G6PD）和非氧化（转酮醇酶、TKT）戊糖磷酸途径的影响(PPP)。 LC3C 的作用是针对 PPP 的，不会影响糖酵解途径，该途径会产生用于产生核酸的 5-磷酸核糖和用于脂质合成和谷胱甘肽还原的 NADPH。 KIRC TCGA 进一步发表的无监督分析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。该提议的假设是，通过 HIF 诱导丧失 VHL 会减少 LC3C，从而激活 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 抑制 LC3C。在目标 2 中，我们将确定 LC3C 在控制 PPP 氧化和非氧化分支活性中的作用。使用遗传和代谢组学方法进行核酸合成和 NADPH 生成 在目标 3 中，我们将确定 PPP 的氧化和非氧化分支在人肾 ccRCC 标本中原位异种移植肿瘤生长和 PPP 酶表达中的作用。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，支持我们的工作假设。初步数据显示，LC3C 效应的特异性是由 LC3C C 端肽介导的。