Identifying a nodal point for G alpha q signaling in eye disease

确定眼部疾病中 G α q 信号传导的节点

• 批准号: 9197973
• 负责人: SHANNON J ODELBERG
• 金额: $ 34.08万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9197973
• 关键词: BRAF gene; Biological Assay; Blood Vessels; Cause of Death; Cell Nucleus; Cell membrane; Choroid; Cutaneous Melanoma; Data; Disease; Eye; Eye Neoplasms; Eye diseases; FZD4 gene; G(q) Alpha; G-substrate; GNAQ gene; GTP-Binding Proteins; Gene Silencing; Genetic Transcription; Glaucoma; Growth; Human; In Vitro; Individual; Liver; Lung; MAP Kinase Gene; Malignant Neoplasms; Mediating; Melanoma Cell; Methods; Molecular Target; Monomeric GTP-Binding Proteins; Mutation; Neoplasm Metastasis; Nodal; Nuclear Translocation; Oncogenic; Organ; Pathway interactions; Patients; Pharmacotherapy; Phospholipase C; Play; Protein Kinase C; Proteins; RNA Interference; Research Personnel; Retina; Role; Running; Signal Pathway; Signal Transduction; Signaling Protein; Structure of lamina episcleralis; Sturge-Weber Syndrome; Testing; Transcription Factor AP-1; Treatment Efficacy; Uveal Melanoma; WNT Signaling Pathway; WNT5A gene; Xenograft Model; Xenograft procedure; base; beta catenin; conjunctiva; drug development; effective therapy; in vivo; in vivo Model; knock-down; malformation; mouse model; phospholipase C beta; protein kinase C beta; public health relevance; small hairpin RNA; small molecule; small molecule inhibitor; therapeutic target; trafficking; tumor; tumorigenesis

 DESCRIPTION (provided by applicant): Activating mutations in two Gproteins of the q class (Gq), GNAQ and GNA11, are the drivers of oncogenesis in approximately 80% of uveal melanomas. Similar activating mutations of GNAQ are also found in patients with Sturge-Weber syndrome, which can manifest itself as glaucoma and vascular malformations of the conjunctiva, choroid, retina, and episclera. Uveal melanoma is the most common primary ocular tumor, and in approximately 50% of the cases, the tumor will metastasize to other organs, primarily the liver. Once metastasized, the disease is invariably fatal. Activating GNAQ and GNA11 mutations drive uveal melanoma oncogenesis via the control of several recently identified signaling pathways, including phospholipase C- /protein kinase C (PLC-/PKC) and TRIO-RhoA/Rac1 pathways, which activate MAPK/ERK and YAP to induce AP1- and YAP-TEAD-mediated transcription. However, the mechanism(s) by which Gq proteins activate multiple downstream pathways has not been completely elucidated. Preliminary data suggest that the small GTPase ARF6 may act as an immediate downstream effector of activated GNAQ/GNA11 to control all of the currently known oncogenic Gq signaling pathways. Other preliminary data also suggest that Gq may signal through ARF6 to activate -catenin signaling by promoting the relocalization of -catenin from the cell membrane to the nucleus where it can mediate gene transcription. Preliminary data also support the in vivo role of ARF6 in uveal melanoma. When ARF6 is silenced in uveal melanoma by shRNA or is inhibited with a small molecule inhibitor, tumor establishment and growth is significantly inhibited in an orthotopic xenograft mouse model. Based on these preliminary data, the following aims will be pursued. In Aim 1, we will investigate whether activated Gq proteins induce -catenin signaling via activation of ARF6 in uveal melanoma. We will employ gene silencing via RNA interference and small molecule inhibition of selected targets to assess intracellular localization, transcriptional activity, and function of -catenin in uveal melanoma. In Aim 2, we will elucidate the role of ARF6 in orchestrating known downstream signaling pathways of oncogenic Gq. The same strategies used in Aim 1 will be employed to determine whether ARF6 acts as an immediate downstream effector of activating GNAQ/GNA11 mutations to control (PLC-/PKC) and TRIORhoA/ Rac1 pathways and AP-1 and YAP-TEAD-mediated transcription. In Aim 3, we will assess the in vivo function of ARF6 in tumor establishment and growth by using orthotopic xenograft models of human uveal melanoma. The successful completion of these aims will allow us to determine whether ARF6 plays a critical role in Gq signaling, thus providing a promising therapeutic target for the development of drugs that could be used to treat uveal melanoma and possibly other Gq-related disorders such as Sturge-Weber syndrome.

 描述（由申请人提供）：q 类 (Gαq) 的两种 Gα 蛋白 GNAQ 和 GNA11 的激活突变是约 80% 葡萄膜黑色素瘤中肿瘤发生的驱动因素。还发现了类似的 GNAQ 激活突变。斯特奇-韦伯综合征患者可表现为青光眼和结膜血管畸形，脉络膜、视网膜和巩膜外层黑色素瘤是最常见的原发性眼部肿瘤，在大约 50% 的病例中，肿瘤会转移到其他器官，主要是肝脏，一旦转移，这种疾病总是致命的。 GNA11 突变通过控制几个最近发现的信号通路（包括磷脂酶 C- /蛋白激酶 C）驱动葡萄膜黑色素瘤发生(PLC-/PKC) 和 TRIO-RhoA/Rac1 途径，激活 MAPK/ERK 和 YAP 诱导 AP1 和 YAP-TEAD 介导的转录。然而，Gq 蛋白激活多个下游的机制。初步数据表明，小 GTPase ARF6 可能作为激活的 GNAQ/GNA11 的直接下游效应器来控制所有目前已知的通路。其他初步数据还表明，Gαq 可能通过 ARF6 发出信号，通过促进 β-连环蛋白从细胞膜重新定位到细胞核，从而介导基因转录。也支持 ARF6 在葡萄膜黑色素瘤中的体内作用，当 ARF6 在葡萄膜黑色素瘤中被 shRNA 沉默或被小分子抑制剂抑制时，在原位异种移植小鼠模型中，肿瘤的形成和生长受到显着抑制，在目标 1 中，我们将研究激活的 Gq 蛋白是否通过激活 ARF6 来诱导 -连环蛋白信号传导。我们将通过 RNA 干扰和小分子抑制选定的靶点来进行基因沉默，以评估细胞内定位、转录。 在目标 2 中，我们将阐明 ARF6 在协调致癌 Gαq 的已知下游信号通路中的作用，将采用与目标 1 中使用的相同策略来确定 ARF6 是否起作用。作为激活 GNAQ/GNA11 突变以控制 (PLC-/PKC) 和 TRIORhoA/ Rac1 途径的直接下游效应子在目标 3 中，我们将通过使用人类葡萄膜黑色素瘤的原位异种移植模型来评估 ARF6 在肿瘤建立和生长中的体内功能。确定 ARF6 是否在 Gq 信号传导中发挥关键作用，从而为开发可用于治疗葡萄膜黑色素瘤和可能的其他 Gq 相关疾病（例如称为斯特奇-韦伯综合症。