HIF-2alpha mediated mitophagy and lipogenesis in clear cell renal cell carcinoma

HIF-2α 介导透明细胞肾细胞癌中的线粒体自噬和脂肪生成

基本信息

批准号：
8654488
负责人：
Bo Qiu
金额：
$ 4.27万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-04-01 至 2016-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8654488
关键词：
Affect Antibodies Apoptosis Appearance Autophagocytosis BCL2/Adenovirus E1B 19kd Interacting Protein 3-Like Biology Breast Carcinoma Cell Culture Techniques Cell Line Cell Proliferation Cell Survival Cells Cellular Stress Cellular Stress Response Clear Cell Cleaved cell Cytotoxic Chemotherapy Cytotoxic agent Development Disease Disease Progression Essential Genes Exhibits FASN gene Fatty Acids Gene Expression Profiling Genes Genetic Growth Homeostasis Human Hypoxia Inducible Factor Immunohistochemistry In Vitro Investigation Ionizing radiation Kidney Kidney Neoplasms Life Lipids Maintenance Malignant Epithelial Cell Malignant Neoplasms Mediating Membrane Metabolism Microarray Analysis Mitochondria Modeling Molecular Mutation Nutrient Oxidation-Reduction Oxidative Stress Oxygen Pathogenesis Pathway interactions Patients Phenotype Play Process Production Prostate carcinoma Radiation Reactive Oxygen Species Refractory Regulation Renal Cell Carcinoma Renal carcinoma Research Resistance Role Sampling Serum Small Interfering RNA Source Specimen Testing Tumor Suppressor Proteins Tumor Tissue Up-Regulation Work Xenograft Model Xenograft procedure angiogenesis bHLH-PAS factor HLF base chemotherapy hypoxia inducible factor 1 improved in vivo insight lipid biosynthesis mouse model neoplastic cell new therapeutic target novel pre-clinical prevent programs public health relevance response role model tool tumor tumor growth tumor microenvironment tumor xenograft

项目摘要

DESCRIPTION (provided by applicant): Clear cell renal cell carcinoma (ccRCC) is the most common renal malignancy worldwide. While metastatic ccRCC is refractory to conventional cytotoxic drugs and radiation, life-extending targeted therapies have emerged from an understanding of the molecular pathogenesis of this disease. In particular, over 80% of ccRCC cases exhibit constitutive activation of Hypoxia Inducible Factor (HIF)-dependent transcriptional responses, mediated by heterodimers of HIF-¿ subunits (HIF-1¿ or HIF-22¿) and HIF-1¿. In the case of ccRCC, it is clear that HIF-2¿, but not HIF-1¿, is required for disease progression. While HIF-2¿ is not required for in vitro cell proliferation under oxygen, serum, and nutrient-replete conditions, xenograft mouse models have revealed that HIF-2¿ is essential for in vivo tumor growth, suggesting that HIF-2¿ mediates vital cellular stress responses within the in vivo tumor microenvironment. However, the downstream effectors of HIF-2¿'s tumor-promoting activity remain incompletely understood. Using gene expression profiling, I have identified candidate HIF-2¿ regulated pathways in ccRCC by acutely suppressing HIF-2¿ activity by siRNA. These results indicate that HIF-2¿ regulates essential genes mediating mitophagy (NIX) and de novo lipogenesis (SREBF1, ACLY, ACACB, FASN, SCD1). NIX-dependent mitophagy plays a vital role in preventing oxidative stress by eliminating damaged mitochondria, the primary endogenous source of cellular reactive oxygen species (ROS). While HIF-2¿ has been demonstrated to promote resistance to ionizing radiation-induced oxidative stress and apoptosis, the precise mechanism is not clear. Thus, my first hypothesis (AIM1) is that HIF-2¿-dependent mitophagy is required to maintain redox homeostasis and support tumor cell metabolism. Additionally, constitutive de novo lipogenesis is needed for viability and growth in multiple malignancies, including breast and prostate carcinoma. Despite the observation that ccRCC are lipid laden, a phenotype lost upon HIF-2¿ suppression in xenograft tumor models, the role of de novo lipogenesis in ccRCC is unknown. Notably, HIF-2¿-dependent upregulation of TGF-¿ expression is required for serum-independent in vitro proliferation-a condition that likely requires the synthesis of new fatty acids. Thus, my second hypothesis (AIM2) is that HIF-2¿-mediated TGF-¿ expression activates SREBP1-dependent de novo lipogenesis to support tumor cell viability and proliferation. To test these hypotheses, I will utilize cell culture, a muine orthotopic renal tumor model, and primary patient samples to study the regulation of each process by HIF-2¿, evaluate the anti-tumor potential of suppressing these pathways (genetically and pharmacologically), and assess for activation of these processes in human tumors. These findings will provide novel insights into molecular pathogenesis of ccRCC, HIF biology, and potential anti-tumor therapies against ccRCC.

描述（由适用提供）：透明细胞肾细胞癌（CCRCC）是全球最常见的肾脏恶性肿瘤。虽然转移性CCRC对常规的细胞毒性药物和辐射却是耐火的，但源自生命的靶向疗法已经从对该疾病的分子发病机理的理解中出现。特别是，超过80％的CCRCC病例暴露了缺氧诱导因子（HIF）依赖性转录响应的本构激活，这是由HIF-€亚基异二聚体（HIF-1或HIF-1或HIF-22或HIF-1）介导的。就CCRC而言，很明显，疾病进展需要HIF-2,1-但不是HIF-1。虽然在氧气，血清和营养复发条件下体外细胞增殖并不需要HIF-2虽然异种移植小鼠模型表明，HIF-2¿对于体内肿瘤的生长至关重要，这表明HIF-2介导了体内体内肿瘤微型环境中重要的细胞应力反应。然而，HIF-2？促进肿瘤活性的下游效应尚不完全了解。使用基因表达分析，我通过急性抑制siRNA的HIF-2活动来鉴定CCRCC中的候选HIF-2。这些结果表明，HIF-2。调节介导线粒体（NIX）和从头脂肪生成的必需基因（SREBF1，ACLY，ACACB，FASN，SCD1）。 NIX依赖性线粒体在防止氧化应激方面起着至关重要的作用，这是通过消除细胞活性氧（ROS）的主要内源性内源性来源的受损线粒体。虽然已证明HIF-2促进了电离辐射诱导的氧化应激和凋亡的电离抗性，但精确机制尚不清楚。这是我的第一个假设（AIM1）是HIF -2¿依赖性线索需要维持氧化还原稳态并支持肿瘤细胞代谢。此外，在包括乳腺癌和前列腺癌在内的多种恶性肿瘤的生存力和生长中，需要从头开始脂肪生成。尽管观察到CCRC是脂质的，但在异种移植肿瘤模型中HIF-2抑制时丢失了表型，但从头脂肪生成在CCRCC中的作用尚不清楚。值得注意的是，HIF-2¿-依赖性TGF- - 表达的更新是血清独立于体外增殖所必需的，这可能需要合成新的脂肪酸。这是我的第二个假设（AIM2）是HIF-2¿介导的TGF-¿表达激活了SREBP1依赖性的从头脂肪形成，以支持肿瘤细胞的生存能力和增殖。为了检验这些假设，我将利用细胞培养，一种原位原位肾肿瘤模型和主要的患者样本来研究通过HIF-2€的每个过程，评估抑制这些途径（遗传学和药理上）的抗肿瘤潜力，并评估人类肿瘤中这些过程的激活。这些发现将为CCRCC，HIF生物学和针对CCRCC的潜在抗肿瘤疗法提供新的见解。