The GNAQ pathway as a therapeutic target in uveal melanoma

GNAQ 通路作为葡萄膜黑色素瘤的治疗靶点

• 批准号: 7768728
• 负责人: Boris C. Bastian
• 金额: $ 32.06万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-01 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7768728
• 关键词: Affinity Chromatography; Apoptosis; BRAF gene; Biological Markers; Blue Nevus; Candidate Disease Gene; Cell Line; Clinical; Codon Nucleotides; Collaborations; Complement; Cutaneous Melanoma; DNA copy number; Data; Development; Disease; Endothelin; Family member; G Protein-Coupled Receptor Signaling; G(q) Alpha; G-Protein-Coupled Receptors; GNAQ gene; Gene Expression; Genes; Genomics; Goals; Heterotrimeric GTP-Binding Proteins; Homeostasis; Human; Kinetics; Light; Malignant Neoplasms; Mediating; Melanoma Cell; Metastatic Lesion; Metastatic Neoplasm to the Liver; Mitogen-Activated Protein Kinases; Modeling; Mus; Mutation; Neoplasm Metastasis; Neoplasms; Oncogenes; Pathway interactions; Pattern; Pharmacologic Substance; Phosphorylation; Proteins; Proteomics; Resolution; Sampling; Sequence Analysis; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Somatic Mutation; Staging; Survival Rate; Time; United States; Uveal Melanoma; Xenograft Model; base; cell growth; comparative genomic hybridization; effective therapy; gain of function; genome-wide; in vivo; loss of function; melanocyte; melanoma; mouse model; mutant; novel; novel therapeutics; pre-clinical; preclinical study; protein expression; public health relevance; receptor; response; therapeutic target; treatment strategy; tumorigenesis

DESCRIPTION (provided by applicant): Uveal melanoma is the most common intraocular malignancy in the United States and has a 10-year disease specific survival rate of 50%. No effective treatment options exist. While activation of the mitogen-activated protein (MAP) kinase pathway is a common feature in uveal melanoma, mutations in known melanoma oncogenes such as BRAF, NRAS, or KIT are absent. We recently identified somatic mutations in the heterotrimeric G protein alpha q subunit, GNAQ, in 46% of uveal melanomas. Mutations of GNAQ were found in primary and metastatic lesions as well as over 80% of blue nevi and 2% of cutaneous melanomas. GNAQ mutations are found in a mutually exclusive pattern with BRAF, NRAS, or KIT and turn GNAQ into a dominant acting oncogene. siRNA-mediated knockdown in GNAQ -mutant melanoma cell lines leads to marked apoptosis. We identified MAP-kinase activation as one contributing factor to GNAQ-mediated oncogenesis. However, the factors involved in this activation and what other pathways are involved in oncogenesis are currently unknown. In this study we will fill this gap, evaluate GNAQ as a therapeutic target in a preclinical setting, and search for additional oncogenes that are functionally related. In Aim 1 we will determine how GNAQ mutation contributes to melanoma formation using candidate and unbiased approaches to identify the downstream effectors of mutant GNAQ in melanoma. We will carry out gain and loss of function studies in primary melanocytes and uveal melanoma cells, respectively and determine the protein expression and phosphorylation kinetics of canonical downstream signaling targets. These analyses will be complemented by data from already ongoing genome wide expression analyses aimed at identifying the signaling networks downstream of GNAQ as well as proteomic analysis to identify GNAQ's immediate effectors in melanoma. In aim 2 we will validate mutant GNAQ as a therapeutic target in melanoma by carrying out a pre-clinical trial in murine xenograft models of liver metastasis, which is the predominant metastatic site in humans. This aim will be carried out in collaboration with Alnylam, who will provide us with anti- GNAQ siRNA formulated for in vivo use. In aim 3 we will identify possible additional oncogenes using an integrated genomics approach. We will perform detailed comparisons of the clinicopathological features and the activation status of the downstream pathways (aim 1) between uveal melanomas with and without GNAQ mutations to determine whether uveal melanomas without mutations harbor alterations in functionally related genes. We will attempt to identify these genes by determining genomic regions of divergent copy number between the two groups, using high-resolution array-based comparative genomic hybridization and re-sequence the implicated candidate genes. PUBLIC HEALTH RELEVANCE: Uveal melanoma is a highly aggressive form of cancer with no effective treatment, in part because the underlying mechanistic alterations were previously unknown. We have recently discovered mutations in the gene GNAQ, which drive aberrant cell growth in 50% of this melanoma type. The goal of this project is to study its function and develop rationally-based treatment strategies and to discover the equivalent genetic alterations in the remaining 50% of uveal melanomas.

描述（由申请人提供）：葡萄膜黑色素瘤是美国最常见的眼内恶性肿瘤，10 年疾病特异性生存率为 50%。不存在有效的治疗方案。虽然丝裂原激活蛋白 (MAP) 激酶通路的激活是葡萄膜黑色素瘤的常见特征，但已知黑色素瘤癌基因（如 BRAF、NRAS 或 KIT）不存在突变。 我们最近在 46% 的葡萄膜黑色素瘤中发现了异源三聚体 G 蛋白 α q 亚基 GNAQ 的体细胞突变。 GNAQ 突变发现于原发性和转移性病变以及超过 80% 的蓝痣和 2% 的皮肤黑色素瘤中。 GNAQ 突变与 BRAF、NRAS 或 KIT 呈相互排斥的模式，并将 GNAQ 转变为显性作用癌基因。 GNAQ 突变黑色素瘤细胞系中 siRNA 介导的敲低导致显着的细胞凋亡。我们确定 MAP 激酶激活是 GNAQ 介导的肿瘤发生的影响因素之一。然而，目前尚不清楚参与这种激活的因素以及参与肿瘤发生的其他途径。在这项研究中，我们将填补这一空白，在临床前环境中评估 GNAQ 作为治疗靶点，并寻找功能相关的其他癌基因。 在目标 1 中，我们将使用候选和无偏的方法来确定 GNAQ 突变如何促进黑色素瘤形成，以识别黑色素瘤中突变 GNAQ 的下游效应器。我们将分别对原代黑色素细胞和葡萄膜黑色素瘤细胞进行功能获得和丧失的研究，并确定典型下游信号传导靶点的蛋白质表达和磷酸化动力学。这些分析将得到正在进行的全基因组表达分析的数据的补充，这些分析旨在识别 GNAQ 下游的信号网络，以及蛋白质组分析，以识别 GNAQ 在黑色素瘤中的直接效应子。在目标 2 中，我们将通过在小鼠肝转移异种移植模型（人类主要转移部位）中进行临床前试验，验证突变型 GNAQ 作为黑色素瘤的治疗靶点。这一目标将与 Alnylam 合作实现，Alnylam 将为我们提供用于体内使用的抗 GNAQ siRNA。 在目标 3 中，我们将使用综合基因组学方法识别可能的其他癌基因。我们将对有和没有 GNAQ 突变的葡萄膜黑色素瘤的临床病理特征和下游通路（目标 1）的激活状态进行详细比较，以确定没有突变的葡萄膜黑色素瘤是否存在功能相关基因的改变。我们将尝试通过使用基于高分辨率阵列的比较基因组杂交确定两组之间不同拷贝数的基因组区域来识别这些基因，并对所涉及的候选基因进行重新测序。公众健康相关性：葡萄膜黑色素瘤是一种高度侵袭性的癌症，目前尚无有效的治疗方法，部分原因是之前未知其潜在的机制改变。我们最近发现了 GNAQ 基因突变，该突变导致 50% 的这种黑色素瘤类型出现异常细胞生长。该项目的目标是研究其功能并制定合理的治疗策略，并发现其余 50% 的葡萄膜黑色素瘤中的等效基因改变。