Molecular Therapeutics of Kidney Cancer: MET Gene and BHD Gene

肾癌的分子治疗-MET基因和BHD基因 导致肾癌的基因突变提供了发展分子治疗方法的机会。 治疗这种疾病。我们已经确定了3种导致肾癌的基因： VHL基因（肾透明细胞癌）; c-Met基因（乳头状1型肾癌）; 和BHD基因（肾嫌色细胞癌）。靶向MET基因：1型乳头状瘤 我们已经在患者的生殖系中发现了MET基因的激活突变。 遗传性乳头状肾细胞癌（HPRC）以及来自 散发性1型乳头状肾癌患者的研究正在进行中，以针对 乳头状肾癌中c-Met 1型乳头状肾癌基因通路met基因 编码全身循环生长因子、肝细胞的细胞表面受体 生长因子（HGF）。在HPRC激酶和体细胞中鉴定的生殖系突变 散发性1型乳头状肾癌的c-Met癌基因突变位于 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，以评估阻断这种作用的药物的作用。 癌症基因途径作为治疗1型乳头状肾的潜在方法 carcinoma.靶向BHD基因：嫌色肾癌BHD基因是基因的， 与Birt-Hogg-Dub综合征相关的遗传性嫌色肾癌。当我们 发现BHD基因，这是一个新的基因，没有已知的功能。目前正在进行研究 以确定BHD基因是哪种类型的癌症基因，它如何正常发挥作用以及如何损害 该基因导致嫌色肾癌。我们已经确定了BHD基因的突变 在94%的BHD家庭测试。为了确定BHD基因是什么类型的基因，我们 在来自BHD的肾肿瘤标本中搜索该基因的第二拷贝的突变 患者我们发现了第二个拷贝（野生型）的突变（或杂合性丢失 拷贝）的BHD基因。这些发现提供了 证明BHD基因是一种功能丧失的肿瘤抑制基因。当我们发现BHD的时候 该基因是一个功能未知的新基因。为了确定 BHD基因是我们进行研究，以确定哪些蛋白质结合BHD蛋白（称为 卵泡素）。我们发现，卵泡素结合到一种新的蛋白质，称为FNIP1（卵泡素 相互作用蛋白），FNIP1与AMPK结合，AMPK是细胞的主要能量传感蛋白。 AMPK磷酸化FNIP 1和AMPK，FNIP磷酸化卵泡素。AMPK抑制 MTOR通过TS途径的功能。我们发现MTOR使卵泡素磷酸化， 这种磷酸化在体外通过用雷帕霉素处理而被抑制。我们随后 发现卵泡素与第二种蛋白质FNIP2结合，FNIP2也与AMPK结合， 也被AMPK磷酸化，AMPK/FNIP2磷酸化卵泡素。Folliculin和FNIP1 FNIP1和FNIP2共定位于细胞质中，并且卵泡素与FNIP1和FNIP2的结合是在细胞质中进行的。 蛋白质的羧基末端。发现生殖系BHD突变是 预测会截短蛋白质的主要突变（移码或无义 突变）表明卵泡素与FNIP1/FNIP2的结合对卵泡素肿瘤至关重要。 抑制功能为了建立BHD动物模型，进一步了解其作用 BHD基因的突变，并提供一个模型，评估靶向治疗，我们 开发了肾特异性BHD敲除小鼠。在该模型中，BHD-/-小鼠发育为大 囊性肾，伴有增生组织区域。这些动物出现肾功能不全 只能存活30天为了评估靶向治疗的效果 BHD基因途径的方法用雷帕霉素处理BHD-/-动物。的 雷帕霉素处理的动物的肾表型显著减少， 存活率翻倍。我们开发了一种独特的人类肾癌细胞体外模型 线从BHD患者，并正在评估多种药物与目标的BHD途径，在我们的 体内和体外模型。这些研究为制定有针对性的 BHD相关性肾癌的治疗方法以及BHD相关性肾癌患者亚组的治疗方法 散发性非遗传性嫌色细胞肾癌

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.