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：
8828614
负责人：
Bo Qiu
金额：
$ 2.98万
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/8828614
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 Health 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 cytotoxic radiation hypoxia inducible factor 1 improved in vivo insight lipid biosynthesis mouse model neoplastic cell new therapeutic target novel pre-clinical prevent programs response role model targeted treatment 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（由申请人提供）：透明细胞肾细胞癌（ccRCC）是世界范围内最常见的肾脏恶性肿瘤，虽然转移性 ccRCC 对常规细胞毒性药物和放射治疗无效，但随着对透明细胞肾细胞癌分子发病机制的了解，已经出现了延长生命的靶向治疗。特别是，超过 80% 的 ccRCC 病例表现出由缺氧诱导因子 (HIF) 介导的转录反应的组成型激活。 HIF-¿异二聚体亚基（HIF-1¿ 或 HIF-22¿）和 HIF-1¿就 ccRCC 而言，很明显 HIF-2¿ ，但不是 HIF-1¿ ，是疾病进展所必需的。在氧气、血清和营养充足的条件下，体外细胞增殖不需要 HIF-2，异种移植小鼠模型表明，HIF-2¿对于体内肿瘤生长至关重要，这表明 HIF-2¿然而，HIF-2 的下游效应器在体内肿瘤微环境中介导重要的细胞应激反应。通过基因表达谱分析，我已经确定了候选 HIF-2 的肿瘤促进活性。通过急性抑制 HIF-2 调节 ccRCC 通路这些结果表明 HIF-2¿调节介导线粒体自噬 (NIX) 和从头脂肪生成的重要基因（SREBF1、ACLY、ACACB、FASN、SCD1），NIX 依赖性线粒体自噬通过消除受损的线粒体（细胞活性氧的主要内源性来源）在预防氧化应激中发挥着至关重要的作用。 (ROS).而HIF-2¿已被证明可以促进对电离辐射引起的氧化应激和细胞凋亡的抵抗，但其确切机制尚不清楚，因此，我的第一个假设（AIM1）是 HIF-2¿维持氧化还原稳态和支持肿瘤细胞代谢需要依赖线粒体自噬，此外，多种恶性肿瘤（包括乳腺癌和前列腺癌）的生存和生长需要组成性从头脂肪生成，尽管观察到 ccRCC 充满脂质，但其表型却消失了。 HIF-2??在异种移植肿瘤模型中，HIF-2 的从头脂肪生成的作用尚不清楚。 -TGF-的依赖性上调不依赖于血清的体外增殖需要表达，这种情况可能需要合成新的脂肪酸，因此，我的第二个假设 (AIM2) 是 HIF-2¿ -介导的TGF-¿表达激活 SREBP1 依赖性从头脂肪生成，以支持肿瘤细胞活力和增殖。为了检验这些假设，我将利用细胞培养物、小鼠原位肾肿瘤模型和原代患者样本来研究 HIF-2 对每个过程的调节。，评估抑制这些途径（遗传和药理学）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 的分子发病机制、HIF 生物学和潜在的抗肿瘤疗法提供新的见解。 ccRCC。