A novel approach for the selective inhibition of HIF-2a in kidney cancer

选择性抑制肾癌中 HIF-2a 的新方法

• 批准号: 9767082
• 负责人: Mei Yee Koh
• 金额: $ 32.68万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-19 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9767082
• 关键词: 5' Untranslated Regions; Affect; Automobile Driving; Binding; Clear Cell; Clear cell renal cell carcinoma; Clinical; Disease; Drug resistance; Elements; Etiology; Genes; Genetic; Genetic Transcription; Goals; Growth; Heterodimerization; Human; Hypoxia; Hypoxia Inducible Factor; In Vitro; Iron; Iron Chelating Agents; Iron Regulatory Protein 1; KRAS2 gene; Kidney; Link; Mediating; Medical; Messenger RNA; Metabolism; Molecular Target; Mutation; Neoplasm Metastasis; Oral; Patients; Physiological; Play; Production; Proteins; Proteomics; Regulation; Renal Cell Carcinoma; Renal carcinoma; Resistance; Role; Sampling; Series; Solid Neoplasm; Sulfur; TP53 gene; Therapeutic; Tissues; Translations; Tumor Suppressor Genes; Tumor Suppressor Proteins; Xenograft procedure; advanced disease; angiogenesis; base; cancer cell; cancer therapy; cell type; checkpoint inhibition; clinically relevant; high throughput screening; in vivo; in vivo Model; inhibitor/antagonist; iron metabolism; novel strategies; response; small molecule; small molecule inhibitor; targeted agent; therapeutic target; treatment response; tumor; tumor growth; tumor progression; uptake

Clear cell type renal cell carcinoma (CCRCC) is the most common and aggressive form of kidney cancer, and is among the most resistant of solid tumors to therapy. CCRCC is typically initiated by inactivation of the von Hippel Lindau (VHL) tumor suppressor gene, resulting in the constitutive activation of the hypoxia inducible factors, HIF-1α and HIF-2α. CCRCC progression is uniquely driven by HIF-2α, whereas HIF-1α plays a tumor suppressor role. Thus, HIF-2α is an attractive therapeutic target for CCRCC. Through a high throughput screening campaign, we have identified a series of compounds that selectively decrease HIF-2α protein and activity without affecting HIF-1α. We show that these compounds act by enhancing the binding of iron regulatory protein (IRP)-1 to the iron-responsive element (IRE) within the 5' untranslated region of HIF-2α mRNA, which inhibits HIF-2α translation. Using an unbiased global proteomic screen, we confirm Iron-sulfur Cluster Assembly 2 (ISCA2) as the molecular target of these compounds. ISCA2 regulates the incorporation of the iron-sulfur cluster into IRP-1, which modulates its IRE-binding activity. ISCA2 is non-transcriptionally induced by hypoxia, and is a putative pVHL target, suggesting that ISCA2 may play a hypoxia- or CCRCC- specific role. We observe that both ISCA2 and cellular iron are upregulated in CCRCC compared to paired normal kidney, and are significantly correlated. Inhibition of ISCA2 selectively decreases HIF-2α protein without affecting HIF-1α, and depletes cellular iron independently of HIF-2α. Significantly, ISCA2 inhibition by small molecules inhibits CCRCC xenograft growth, and decreases intra-tumoral HIF-2α protein. Thus, our hypothesis is that “ISCA2 plays a central role in promoting the elevation of HIF-2α and cellular iron that drive CCRCC progression. Hence, the targeting of ISCA2 provides a novel strategy for the specific inhibition of HIF- 2α and depletion of cellular iron for the treatment of CCRCC”. Our first aim is to identify the mechanisms mediating ISCA2 induction in hypoxia; and to characterize its role in the regulation of HIF-2α and iron metabolism in CCRCC. Our second aim is to investigate the impact of ISCA2 modulation on CCRCC progression using in vitro and in vivo models, and to determine its physiological relevance using clinical samples of human CCRCC (samples from 600 patients obtained). Our third aim is to investigate the therapeutic impact of ISCA2 inhibition on HIF-2α and cytoplasmic iron, and to explore its use for the treatment of CCRCC. The overall goal of our studies is to identify the mechanisms by which ISCA2, HIF-2α and the deregulation of iron metabolism contribute to CRCC progression; and to determine whether ISCA2 inhibition will yield increased therapeutic benefit for patients with CCRCC.

透明细胞型肾细胞癌 (CCRCC) 是最常见且最具侵袭性的肾癌形式， 是对治疗最具抵抗力的实体瘤之一。 CCRCC 通常是由 von 失活启动的。 Hippel Lindau (VHL) 肿瘤抑制基因，导致缺氧诱导因子的组成型激活 因子，HIF-1α 和 HIF-2α。 CCRCC 进展是由 HIF-2α 独特驱动的，而 HIF-1α 则在肿瘤中发挥作用 抑制器的作用。因此，HIF-2α是 CCRCC 有吸引力的治疗靶点。通过高吞吐量 通过筛选活动，我们发现了一系列选择性降低 HIF-2α 蛋白和 活性而不影响 HIF-1α。我们证明这些化合物通过增强铁的结合来发挥作用 调节蛋白 (IRP)-1 与 HIF-2α 5' 非翻译区内的铁反应元件 (IRE) mRNA，抑制 HIF-2α 翻译。使用公正的全球蛋白质组学筛选，我们确认了铁硫 Cluster Assembly 2 (ISCA2) 作为这些化合物的分子靶点。 ISCA2 规范了以下内容的合并： 将铁硫簇转化为 IRP-1，从而调节其 IRE 结合活性。 ISCA2 是非转录的 由缺氧诱导，并且是假定的 pVHL 靶标，表明 ISCA2 可能发挥缺氧或 CCRCC- 作用 具体作用。我们观察到，与配对相比，CCRCC 中 ISCA2 和细胞铁的表达上调 正常肾脏，且呈显着相关。抑制 ISCA2 选择性降低 HIF-2α 蛋白 不影响 HIF-1α，并且独立于 HIF-2α 消耗细胞铁。值得注意的是，ISCA2 抑制 小分子抑制 CCRCC 异种移植物生长，并减少肿瘤内 HIF-2α 蛋白。因此，我们的 假设是“ISCA2 在促进 HIF-2α 和细胞铁的升高方面发挥着核心作用，而细胞铁则驱动 CCRCC进展。因此，靶向 ISCA2 为特异性抑制 HIF-提供了一种新策略。 2α 和细胞铁耗竭治疗 CCRCC”。我们的首要目标是确定其机制 介导缺氧状态下 ISCA2 的诱导；并表征其在 HIF-2α 和铁的调节中的作用 CCRCC 中的新陈代谢。我们的第二个目标是研究 ISCA2 调制对 CCRCC 的影响 使用体外和体内模型进行进展，并使用临床确定其生理相关性 人类 CCRCC 样本（从 600 名患者获得样本）。我们的第三个目标是调查 ISCA2 抑制对 HIF-2α 和细胞质铁的治疗影响，并探索其在治疗中的用途 中国铁建的。我们研究的总体目标是确定 ISCA2、HIF-2α 和 铁代谢失调导致CRCC进展；并确定 ISCA2 是否受到抑制 将为 CCRCC 患者带来更多的治疗益处。