REGULATION OF UVEAL MELANOMA CELL FATE BY THE PKC PATHWAY VIA MITF

PKC 途径通过 MITF 调节葡萄膜黑色素瘤细胞的命运

• 批准号: 9749971
• 负责人: Nicholas Mitsiades
• 金额: $ 35.17万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9749971
• 关键词: Adult; Biopsy; Cell Differentiation process; Cell Line; Cell Proliferation; Cells; Chromatin; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cytotoxic Chemotherapy; Data; Development; Disease Resistance; Functional disorder; G alpha q Protein; GNAQ gene; GTP-Binding Protein alpha Subunits, Gs; Genes; Genetic Transcription; Goals; Growth; In Vitro; Innovative Therapy; Malignant Neoplasms; Mediating; Mediator of activation protein; Melanoma Cell; Modeling; Molecular; Mus; Mutation; NCOA3 gene; Oncogenic; PRKCA gene; Pathway interactions; Patients; Pattern; Pharmacology; Phospholipase; Phosphorylation; Property; Protein Inhibition; Protein Kinase C; Protein Kinase C Inhibitor; Proteins; Rare Diseases; Refractory; Regimen; Regulation; Reporting; Research; Resistance; Role; Signal Transduction; Small Interfering RNA; Systemic Therapy; Testing; Therapeutic; Therapeutic Intervention; Transcription Coactivator; Uveal Melanoma; Xenograft Model; anticancer activity; base; chemotherapy; combinatorial; design; experience; experimental study; growth promoting activity; in vivo; innovation; insight; melanocyte; melanoma; microphthalmia-associated transcription factor; mutant; new therapeutic target; novel; novel therapeutic intervention; novel therapeutics; phospholipase inhibitor; protein kinase C beta; protein kinase C kinase; protein kinase D; public health relevance; receptor; restoration; small molecule inhibitor; targeted treatment; therapeutic target; transcription factor

 DESCRIPTION (provided by applicant): Uveal melanoma (UM), the most common intraocular malignancy in adults, is uniformly refractory to all available systemic chemotherapies, and, as a result, is universally lethal when metastatic, creating an unmet need for novel, effective, targeted therapies for this orphan disease. Somatic activating mutations in G(alpha)q and G(alpha)11, present in a mutually exclusive pattern in ~80% of UMs, activate the PKC pathway and function as bona fide oncogenic drivers. As the O'Malley lab had previously reported that steroid receptor coactivator-3 (SRC-3), a transcriptional coactivator with potent growth-promoting activity, is post-translationally stabilized via PKC-mediated phosphorylation, we decided to build upon our experience in SRC-3 studies and examine the role of SRC-3 in UM. Our preliminary studies suggest that G(alpha)-induced oncogenic signaling is mediated by the protein kinase C (PKC)alpha/protein kinase D (PKD) pathway, and leads to stabilization of SRC-3, which then co-localizes on chromatin and co-operates with microphthalmia-associated transcription factor (MITF), a critical transcription factor for melanocytes, to drive oncogenic signaling. G(alpha)q-mutant UM cells are exquisitely dependent on SRC-3 for proliferation/survival in vitro and in vivo. Small molecule inhibitors (SMIs) of PKC cause depletion of SRC-3 protein and exert anticancer activity in G(alpha)q-mutant UM cells, while restoration of SRC-3 expression rescues the viability of UM cells that have been treated with G(alpha)q/PKC inhibition. Based on these recent findings, our core hypothesis is that mutant G(alpha) proteins trigger PKC-mediated intracellular oncogenic signaling that stabilizes SRC-3, which then functions as a coactivator for the transcription factor MITF. Moreover, pharmacological inhibition of SRC-3/MITF will exert potent anticancer activity, thus providing an innovative therapeutic opportunity for UM patients. Our proposal provides the roadmap for the development of such innovative therapies for this highly lethal orphan disease. Our aims are to elucidate the role of SRC-3 in UM pathophysiology and resistance to systemic therapy (in particular PKC inhibitors), and to establish it as a therapeutic target in UM, using a large panel of UM cell lines, primary cultures of UM cells and patient biopsies; examine the cooperation between SRC-3 and MITF, define their transcriptional target genes, determine how these transcriptional targets are regulated by MITF and SRC- 3, and dissect their functional significance in UM; define the activity of newly identified SRC-3/MITF pathway SMIs as a novel therapeutic approach for UM, in particular for disease resistant to targeted therapies using in vitro and in mouse UM models (both as monotherapies and in combination regimens). Our goal is to develop novel targeted therapeutics for UM, with particular emphasis on rationally-designed combinatorial approaches, in order to overcome resistance to treatment. Collectively, our research strategy will enhance our understanding of UM pathophysiology and provide novel targets and therapeutic agents.

 描述（由申请人提供）：葡萄膜黑色素瘤（UM）是成人中最常见的眼内恶性肿瘤，对所有可用的全身化疗均具有耐药性，因此，转移时普遍致命，因此对新颖、有效的治疗方法的需求尚未得到满足，针对这种孤儿疾病的靶向治疗 G(α)q 和 G(α)11 的体细胞激活突变，在约 80% 的患者中以相互排斥的模式存在。 UMs 激活 PKC 通路并作为真正的致癌驱动因素发挥作用，正如 O'Malley 实验室之前报道的那样，类固醇受体辅激活因子 3 (SRC-3) 是一种具有有效的生长促进活性的转录辅激活因子，在翻译后是稳定的。通过 PKC 介导的磷酸化，我们决定利用我们在 SRC-3 研究中的经验来检验 SRC-3 在 UM 中的作用。致癌信号由蛋白激酶 C (PKC)α/蛋白激酶 D (PKD) 通路介导，并导致 SRC-3 稳定，然后共定位于染色质并与小眼相关转录因子 (MITF) 协同作用），黑素细胞的关键转录因子，驱动致癌信号传导 G(α)q 突变型 UM 细胞在体外和体外的增殖/存活都高度依赖于 SRC-3。 PKC 的小分子抑制剂 (SMI) 会导致 G(α)q 突变 UM 细胞耗竭 SRC-3 蛋白并发挥抗癌活性，而恢复 SRC-3 表达可挽救已治疗的 UM 细胞的活力。基于这些最近的发现，我们的核心假设是突变的 G(α) 蛋白触发 PKC 介导的细胞内致癌信号，稳定 SRC-3，然后发挥作用。此外，SRC-3/MITF 的药理学抑制将发挥有效的抗癌活性，从而为 UM 患者提供创新的治疗机会，为这种高度创新的疗法的开发提供了路线图。我们的目标是阐明 SRC-3 在 UM 病理生理学和对全身治疗（特别是 PKC 抑制剂）耐药中的作用，并利用大量的研究将其确立为 UM 的治疗靶点。 UM 细胞系、UM 细胞原代培养物和患者活检；检查 SRC-3 和 MITF 之间的合作，定义它们的转录靶基因，确定这些转录靶标如何受 MITF 和 SRC-3 调节，并剖析它们在 UM 中的功能意义将新发现的 SRC-3/MITF 通路 SMI 的活性定义为 UM 的一种新治疗方法，特别是对于使用体外和小鼠 UM 模型（作为单一疗法和我们的目标是开发针对 UM 的新型靶向疗法，特别强调合理设计的组合方法，以克服治疗耐药性，我们的研究策略将增强我们对 UM 病理生理学的理解并提供新的靶点。和治疗剂。