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: 9361021
• 负责人: Mei Yee Koh
• 金额: $ 34.82万
• 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/9361021
• 关键词: 5' Untranslated Regions; Affect; Automobile Driving; Binding; Clear Cell; 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; clinically relevant; high throughput screening; immune checkpoint; 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）是肾癌最常见，最具侵略性的形式， 是实体瘤治疗的最具耐药性之一。 CCRCC通常是通过失活的von引发的 河马lindau（VHL）肿瘤抑制基因，导致缺氧诱导的构成激活 HIF-1α和HIF-2α的因素。 CCRCC进展是由HIF-2α唯一驱动的，而HIF-1α则播放肿瘤 抑制作用的角色。这是HIF-2α是CCRCC的有吸引力的治疗靶标。通过高通量 筛选运动，我们已经确定了一系列化合物，这些化合物有选择地降低HIF-2α蛋白和 没有影响HIF-1α的活性。我们表明，这些化合物通过增强铁的结合来起作用 在HIF-2α的5'未翻译区域内的铁响应元件（IRE）的调节蛋白（IRP）-1 mRNA，抑制HIF-2α的翻译。使用公正的全球蛋白质组学屏幕，我们确认铁硫 簇组装2（ISCA2）是这些化合物的分子靶标。 ISCA2规范 铁硫簇进入IRP-1，该簇调节其愤怒的结合活性。 ISCA2在非转录上 由缺氧诱导，是推定的PVHL靶标，表明ISCA2可能发挥缺氧或CCRCC- 具体角色。我们观察到，与配对相比 正常肾脏，并且显着相关。 ISCA2的抑制选择性降低HIF-2α蛋白 不影响HIF-1α，并独立于HIF-2α耗尽细胞铁。值得注意的是，ISCA2抑制 小分子抑制CCRCC异种移植的生长，并降低肿瘤内HIF-2α蛋白。那，我们的 假设是“ ISCA2在促进驱动HIF-2α和细胞铁的升高中起着核心作用 CCRCC的进展。因此，ISCA2的靶向为特定抑制HIF提供了新的策略 2α和细胞铁的耗竭以治疗CCRCC”。我们的第一个目的是确定机制 介导缺氧的ISCA2诱导；并表征其在调节HIF-2α和铁中的作用 CCRC中的代谢。我们的第二个目的是研究ISCA2调制对CCRCC的影响 使用体外和体内模型进行进展，并使用临床确定其身体相关性 人类CCRC的样品（来自600名患者的样本）。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，并探索其用于治疗的用途 CCRCC。我们研究的总体目标是确定ISCA2，HIF-2α和 铁代谢的放松​​管制有助于CRCC的进展。并确定ISCA2抑制是否 CCRC患者的治疗益处将增加。