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（由适用提供）：成人最常见的眼内恶性肿瘤（UM）对所有可用的系统性化疗均均匀地耐用，因此，在转移性时，在转移性时普遍致死，这是对这种孤儿病的新颖，有效的，有效的，有效的，有效的，有效的，有效的，有效的，有效的，有效的。在约80％的UM中以互斥模式存在的G（Alpha）Q和G（Alpha）11中的体细胞激活突变，激活PKC途径并充当真正的致癌驱动器。正如O'Malley Lab先前报道的那样，立体接收器共激活器3（SRC-3）是一种具有有效生长活性活性的转录共激活因子，是通过PKC介导的磷酸化稳定的，我们决定根据SRC-3研究和SRC-3研究和检查SRC-3的作用来稳定。 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黑色素细胞，驱动致癌信号。 G（alpha）Q-突变的UM细胞完全取决于SRC-3的体外和体内生存。 PKC的小分子抑制剂（SMI）导致SRC-3蛋白的部署并在G（Alpha）Q-突变剂UM细胞中发挥抗癌活性，而SRC-3表达的恢复挽救了已用G（Alpha）Q/PKC抑制的UM细胞的可行性。基于这些最新发现，我们的核心假设是突变G（alpha）蛋白触发PKC介导的细胞内致癌信号传导稳定SRC-3，然后它是转录因子MITF的共激活因子。此外，对SRC-3/MITF的药物抑制作用将发挥潜在的抗癌活性，从而为UM患者提供创新的治疗机会。我们的建议为这种高度致命的孤儿疾病开发这种创新疗法提供了路线图。我们的目的是阐明SRC-3在UM病理生理学和对全身治疗的耐药性（尤其是PKC抑制剂）中的作用，并使用大型UM细胞系，UM细胞的原发性培养物和患者活检将其确定为UM的疗法靶标。检查SRC-3和MITF之间的合作，定义其转录靶基因，确定如何通过MITF和SRC-3调节这些转录靶标，并剖析其在UM中的功能意义；将新鉴定的SRC-3/MITF途径SMIS定义为UM的一种新型治疗方法，尤其是使用体外和小鼠UM模型（无论是单一疗法和组合方案）抗靶向疗法的疾病。我们的目标是为UM开发新颖的靶向疗法，特别强调合理设计的组合方法，以克服对治疗的抗药性。总的来说，我们的研究策略将增强我们对UM病理生理学的理解，并提供新颖的靶标和治疗剂。