Molecular Therapeutics of Kidney Cancer: MET Gene and BHD Gene

肾癌的分子治疗：MET基因和BHD基因

• 批准号: 7965987
• 负责人: William Marston Linehan
• 金额: $ 139.43万
• 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/7965987
• 关键词: Affect; American; Animal Model; Animals; Area; Binding; Cancer Etiology; Cancer cell line; Cell Surface Receptors; Cells; Clear Cell; Clinical; Code; Cutaneous; Cyst; Cystic kidney; Cytoplasm; Development; Disease; Evaluation; Family; Folliculin; Foundations; Genes; Germ-Line Mutation; Growth Factor; Hepatocyte Growth Factor; Hereditary Neoplastic Syndromes; Hereditary Papillary Renal Carcinoma; Histology; Human; Hybrids; Hyperplasia; In Vitro; Inherited; Kidney; Kidney Neoplasms; Knockout Mice; Lead; Loss of Heterozygosity; Lung; MET Gene Mutation; MET gene; Modeling; Molecular; Mus; Mutation; New Agents; Nonsense Mutation; Oncogenes; Papillary; Pathway interactions; Patients; Phenotype; Phosphorylation; Protein Binding; Proteins; Renal Cell Carcinoma; Renal carcinoma; Risk; Role; Sampling; Sirolimus; Somatic Mutation; Specimen; Syndrome; Testing; Therapeutic; Tissues; Tumor Suppressor Genes; Tumor Suppressor Proteins; Tyrosine Kinase Domain; VHL gene; Work; base; cancer type; in vitro Model; in vivo; kindred; loss of function; meetings; novel; receptor; therapeutic target; tumor

Molecular Therapeutics of Kidney Cancer-MET Gene and BHD 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 MET Gene: Type 1 Papillary Kidney Cancer We have found activating mutations of the MET gene in the germline of patients with Hereditary Papillary Renal Cell Carcinoma (HPRC) as well as in a subset of tumors from patients with sporadic, type 1 papillary kidney cnacer Studies are underway to target the c-Met type 1 papillary kidney cancer gene pathway in papillary kidney cancer. The Met gene codes for a cell surface receptor for a systemically circulating growth factor, hepatocyte growth factor (HGF). The germline mutations identified in the HPRC kindreds and somatic mutations of the c-Met oncogene in sporadic type 1 papillary renal carcinoma are located in the tyrosine kinase domain of the MET gene and are predicted to activate this receptor. 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 type 1 papillary renal carcinoma. Targeting the BHD Gene: Chromophobe Kidney Cancer The BHD gene is the gene for the inherited form of chromophobe kidney cancer associated with Birt-Hogg-Dub syndrome. When we found the BHD gene it was a novel gene with no known function. Studies are currently underway to determine what type cancer gene the BHD gene, how it functions normally and how damage to this gene leads to chromophobe renal carcinoma. We have identified mutations of the BHD gene in 94% of the BHD families tested. In order to determine what type of gene the BHD gene is we searched for mutation of the second copy of the gene in kidney tumor specimens from BHD patients. We found mutation (or loss of heterozygosity) of the second copy (the wild type copy) of the BHD gene in 70% of the tumor samples evaluated. These findings provided the evidence that the BHD gene is a loss of function, tumor suppressor gene. When we found the BHD gene it was a novel gene with unknown function. In order to determine what the function of the BHD gene is we performed studies to determine which proteins bind to the BHD protein (called folliculin). We found that folliculin binds to a novel protein, called FNIP1 (folliculin interacting protein) that FNIP1 binds to AMPK, which is the cells main energy sensing protein. AMPK phosphorylates both FNIP1 and AMPK and FNIP phosphorylate folliculin. AMPK inhibits the function of MTOR through the TS pathway. We found that MTOR phosphorylates folliculin and that this phosphorylation is inhibited in-vitro by treatment with rapamycin. We have subsequently found that folliculin binds to a second protein, FNIP2, which also binds AMPK and which is also phosphorylated by AMPK and that AMPK/FNIP2 phosphorylate folliculin. Folliculin and FNIP1 and FNIP2 co-localize in the cytoplasm and the binding of folliculin to FNIP1 and FNIP2 is in the carboxy terminus of the protein. The finding that the germline BHD mutations are predominantly mutations that are predicted to truncate the protein (frameshift or nonsense mutations) suggests that folliculin binding to FNIP1/FNIP2 is critical to folliculins tumor suppressor function. In order to develop a BHD animal model to further understand the effect of mutation of the BHD gene and to provide a model for evaluation of targeted therapeutics we developed a kidney specific BHD knockout mouse. In this model BHD -/- mice developed large cystic kidneys with areas of hyperplastic tissues. These animals develop renal insufficience and survive for only 30 days. In order to evaluate the effect of a targeted therapeutic approach for the BHD gene pathway the BHD -/- animals were treated with rapamycin. The rapamycin treated animals had a significant diminution in the kidney phenotype and their survival was doubled. We have developed a unique in-vitro model of a human kidney cancer cell line from a BHD patient and are evaluating multiple agents with target the BHD pathway in our in-vivo and in-vitro models. These studies provide the basis for the development of a targeted therapeutic approach for BHD-associated kidney cancer and for a subset of patients with sporadic, non-inherited chromophobe kidney cancer.

肾癌的分子治疗-MET基因和BHD基因了解导致肾癌的基因为开发这种疾病的分子治疗方法提供了机会。我们已经确定了3个导致肾癌的基因：VHL基因(肾透明细胞癌)、c-Met基因(乳头状1型肾癌)和BHD基因(嫌色肾癌)。靶向MET基因：1型乳头状肾癌我们已经在遗传性乳头状肾细胞癌(HPRC)患者的胚系以及散发性1型乳头状肾癌患者的一组肿瘤中发现了MET基因的激活突变。针对乳头状肾癌中c-Met 1型乳头状肾癌基因通路的研究正在进行中。Met基因编码一种系统循环生长因子--肝细胞生长因子(HGF)的细胞表面受体。在HPRC家系中发现的胚系突变和散发性I型乳头状肾癌中c-Met癌基因的体细胞突变位于MET基因的酪氨酸激酶结构域，并被预测激活该受体。体外和体内研究正在进行中，以评估阻断这一癌症基因途径的药物作为治疗1型乳头状肾癌的潜在方法的作用。靶向BHD基因：嫌色肾癌BHD基因是与Birt-Hogg-Dub综合征相关的遗传性嫌色肾癌的基因。当我们发现BHD基因时，它是一个未知功能的新基因。目前正在进行研究，以确定BHD基因是什么类型的癌症基因，它是如何正常发挥作用的，以及该基因的破坏如何导致嫌色肾癌。我们已经在94%的BHD家系中发现了BHD基因的突变。为了确定BHD基因是哪种类型的基因，我们在BHD患者的肾肿瘤标本中寻找该基因第二拷贝的突变。我们发现BHD基因的第二个拷贝(野生型拷贝)的突变(或杂合性丢失)在70%的肿瘤样本中被评估。这些发现为BHD基因是一种功能缺失的肿瘤抑制基因提供了证据。当我们发现BHD基因时，它是一个功能未知的新基因。为了确定BHD基因的功能是什么，我们进行了研究，以确定哪些蛋白质与BHD蛋白(称为毛囊蛋白)结合。我们发现毛囊蛋白与一种新的蛋白质结合，称为FNIP1(毛囊蛋白相互作用蛋白)，FNIP1与AMPK结合，这是细胞主要的能量感应蛋白。AMPK磷酸化FNIP1和AMPK，FNIP磷酸化毛囊。AMPK通过TS途径抑制MTOR的功能。我们发现MTOR使毛囊蛋白磷酸化，这种磷酸化作用在体外被雷帕霉素抑制。我们随后发现，毛囊蛋白与第二个蛋白FNIP2结合，FNIP2也与AMPK结合，也被AMPK磷酸化，AMPK/FNIP2使毛囊磷酸化。卵泡蛋白与FNIP1和FNIP2共定位于细胞质中，与FNIP1和FNIP2的结合位于蛋白质的羧基末端。这一发现表明，卵泡蛋白与FNIP1/FNIP2结合对卵泡蛋白的肿瘤抑制功能至关重要。为了建立BHD动物模型，进一步了解BHD基因突变的影响，并为靶向治疗的评价提供模型，我们建立了肾脏特异的BHD基因敲除小鼠。在这个模型中，BHD-/-小鼠出现了巨大的囊性肾脏，并有大量的增生组织。这些动物会出现肾功能不全，只能存活30天。为了评价靶向治疗BHD基因通路的效果，用雷帕霉素对BHD-/-动物进行了治疗。经雷帕霉素处理的动物肾脏表型明显减少，存活率增加一倍。我们已经从BHD患者身上建立了一个独特的人肾癌细胞株的体外模型，并在我们的体内和体外模型中评估了多种靶向BHD途径的药物。这些研究为BHD相关肾癌和散发性、非遗传性嫌色肾癌患者的靶向治疗方法的发展提供了基础。