Molecular Therapeutics of Kidney Cancer: VHL Gene and Fumarate Hydratase Gene

肾癌的分子治疗：VHL基因和富马酸水合酶基因

• 批准号: 9153752
• 负责人: William Marston Linehan
• 金额: $ 143.7万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9153752
• 关键词: Affect; American; Binding; Cancer Etiology; Cancer Model; Cell Line; Citric Acid Cycle; Clear Cell; Clinical; Clinical Trials; Complex; Conventional (Clear Cell) Renal Cell Carcinoma; Cutaneous Leiomyoma; Development; Disease; Enzymes; Family; Foundations; Fumarate Hydratase; Fumarates; Geldanamycin Analogue; Genes; Genetic Transcription; Goals; Growth; Heat-Shock Proteins 90; Hereditary Leiomyomatosis and Renal Cell Cancer; Hereditary Neoplastic Syndromes; Histology; Human; Hypoxia; Hypoxia Inducible Factor; In Vitro; Inherited; Kidney Neoplasms; Lead; Loss of Heterozygosity; Malignant Neoplasms; Mediating; Molecular; Mutate; Mutation; New Agents; Oncogenes; Papillary; Pathway interactions; Patients; Platelet-Derived Growth Factor; Process; Procollagen-Proline Dioxygenase; Proteins; Renal Cell Carcinoma; Renal carcinoma; Risk; Role; Scientist; Staining method; Stains; System; Therapeutic; Transforming Growth Factor alpha; Tumor Tissue; Ubiquitin; Urologic Oncology; Uterine Fibroids; VHL gene; VHL protein; Vascular Endothelial Growth Factors; Von Hippel-Lindau Syndrome; Work; beta catenin; cancer type; elongin B; elongin C; in vitro Model; in vivo; meetings; novel; prevent; protein complex; receptor; therapeutic target; transcription factor; tumor

Molecular Therapeutics of Kidney Cancer-VHL Gene and Fumarate Hydratase Gene Understanding the genes that cause kidney cancer provides the opportunity to develop approaches for molecular therapeutics for this disease. We have identified 3 genes that cause cancer of the kidney: the VHL gene (clear cell renal cell carcinoma); the c-Met gene (papillary type 1 renal carcinoma); and the BHD gene (chromophobe renal carcinoma). Targeting the VHL Clear Cell Kidney Cancer Gene Pathway Urologic Oncology Branch scientists are studying intensively how damage (mutation) to the VHL gene leads to the manifestations in VHL and sporadic renal carcinoma patients. Recently, it is has been shown that the VHL protein forms a complex with other proteins, including elongin C and B and the CUL-2 protein, and this complex targets the alpha subunit of hypoxia inducible factors (HIF1-alpha and HIF2-alpha) for ubiquitin-mediated degradation. This is a hypoxia-mediated process normally, i.e., under hypoxic conditions HIF is not degraded by the VHL complex. HIF is a transcription factor that regulates the transcription of a number of downstream genes important for cancer, such as VEGF, Glut 1, TGF-alpha and PDGF. When the VHL gene is mutated, in the germline of VHL patients or in tumor tissue from patients with clear cell renal carcinoma, the HIFs cannot be degraded and the result is the over-transcription of VEGF, Glut1, TGF-alpha and PDGF. One approach to evaluating the role of agents targeting the VHL pathway in VHL and clear cell renal carcinoma is to determine the activity of agents which block the VEGF and TGF-alpha/EGFr pathways in-vitro and in-vivo. Another approach for molecular therapeutics of clear cell RCC is by use of agents such as geldanamycin analogues, which disrupt the binding of HIF to HSP-90. In-vitro studies have shown that the 17AAG geldanamycin analogues can degrade HIF even in VHL -/- cell lines. In-vitro and in-vivo studies are underway in kidney cancer models that we have developed from human material to evaluate the role of agents which block this cancer gene pathway as a potential approach for the treatment of clear cell kidney cancer. Clinical trials evaluating the role of geldanamycin analogues as well as agents which target the VEGF/EGFr receptors and other parts of the VHL pathway are currently in progress. Targeting the Fumarate Hydratase Gene: Type 2 Papillary Kidney Cancer The Krebs cycle enzyme, fumarate hydratase (FH), is the gene for Hereditary Leiomyomatosis Renal Cell Carcinoma (HLRCC). HLRCC patients are at risk for the development of cutaneous and uterine leiomyomas as well as a very aggressive form of type 2 papillary kidney cancer. We have found mutations of the FH gene in the germline of 95% of our HLRCC families and loss of heterozygosity of the FH gene in HLRCC-associated kidney cancer. In order to understand how mutation of a Krebs cycle enzyme could cause kidney cancer we stained HLRCC-associated kidney tumors for the presence of hypoxia induced factor 1-alpha (HIF1-alpha) and hypoxia induced factor 2-alpha (HIF2-alpha). We found both HIF1-alpha and HIF2-alpha to be elevated in the HLRCC kidney tumors. We are developing novel in-vitro models from human tumors and evaluating growth in in-vitro and in-vivo systems. In in-vitro models we found that when fumarate hydratase was inactivated (with SiRNA), fumarate increased and the increase in fumarate inhibited prolyl hydroxylase. The inhibition of prolyl hydroxylase prevented normoxic VHL-mediated HIF degradation, providing a VHL-independent mechanism for dysregulation of HIF degradation in HLRCC kidney cancer. These studies provided the rationale for the development of a targeted therapeutic approach for the treatment of HLRCC-associated kidney cancer. In-vitro and in-vivo studies are underway to evaluate the role of agents which block this cancer gene pathway as a potential approach for the treatment of HLRCC-associated as well as sporadic type 2 papillary kidney cancer.

肾癌的分子治疗——VHL 基因和富马酸水合酶基因 了解导致肾癌的基因为开发该疾病的分子治疗方法提供了机会。我们已经鉴定出 3 种导致肾癌的基因：VHL 基因（透明细胞肾细胞癌）； c-Met 基因（1 型乳头状肾癌）；和 BHD 基因（嫌色肾癌）。针对VHL透明细胞肾癌基因通路泌尿肿瘤科的科学家正在深入研究VHL基因的损伤（突变）如何导致VHL和散发性肾癌患者的表现。最近，研究表明VHL蛋白与其他蛋白形成复合物，包括elongin C和B以及CUL-2蛋白，并且该复合物靶向缺氧诱导因子（HIF1-α和HIF2-α）的α亚基用于泛素介导的降解。这通常是缺氧介导的过程，即在缺氧条件下，HIF 不会被 VHL 复合物降解。 HIF 是一种转录因子，可调节许多对癌症重要的下游基因的转录，例如 VEGF、Glut 1、TGF-α 和 PDGF。当VHL基因突变时，在VHL患者的种系或透明细胞肾癌患者的肿瘤组织中，HIF不能被降解，结果是VEGF、Glut1、TGF-α和PDGF的过度转录。评估针对 VHL 通路的药物在 VHL 和透明细胞肾癌中的作用的一种方法是确定体外和体内阻断 VEGF 和 TGF-α/EGFr 通路的药物的活性。透明细胞肾细胞癌的另一种分子治疗方法是使用格尔德霉素类似物等药物，它会破坏 HIF 与 HSP-90 的结合。体外研究表明，17AAG 格尔德霉素类似物甚至可以在 VHL -/- 细胞系中降解 HIF。我们正在利用人体材料开发的肾癌模型进行体外和体内研究，以评估阻断该癌症基因途径的药物的作用，作为治疗透明细胞肾癌的潜在方法。目前正在进行评估格尔德霉素类似物以及针对 VEGF/EGFr 受体和 VHL 途径其他部分的药物作用的临床试验。靶向富马酸水合酶基因：2 型乳头状肾癌 克雷布斯循环酶富马酸水合酶 (FH) 是遗传性平滑肌瘤病肾细胞癌 (HLRCC) 的基因。 HLRCC 患者有患皮肤和子宫肌瘤以及侵袭性极强的 2 型乳头状肾癌的风险。我们在 95% 的 HLRCC 家族的种系中发现了 FH 基因突变，并且在 HLRCC 相关肾癌中发现了 FH 基因杂合性缺失。为了了解克雷布斯循环酶的突变如何导致肾癌，我们对 HLRCC 相关肾肿瘤进行了染色，以确定是否存在缺氧诱导因子 1-α (HIF1-α) 和缺氧诱导因子 2-α (HIF2-α)。我们发现 HIF1-α 和 HIF2-α 在 HLRCC 肾肿瘤中均升高。我们正在开发新型人类肿瘤体外模型，并评估体外和体内系统的生长。在体外模型中，我们发现当富马酸水合酶失活（使用 SiRNA）时，富马酸增加，并且富马酸的增加抑制脯氨酰羟化酶。脯氨酰羟化酶的抑制可阻止含氧量正常的 VHL 介导的 HIF 降解，为 HLRCC 肾癌中 HIF 降解的失调提供了一种独立于 VHL 的机制。这些研究为开发治疗 HLRCC 相关肾癌的靶向治疗方法提供了理论基础。体外和体内研究正在进行中，以评估阻断该癌症基因通路的药物的作用，作为治疗 HLRCC 相关以及散发性 2 型乳头状肾癌的潜在方法。