Identification of Regulators and Effectors of the Oncoprotein CDK8 in Drosophila

果蝇中癌蛋白 CDK8 的调节子和效应子的鉴定

• 批准号: 8635677
• 负责人: Jun-yuan Ji
• 金额: $ 7.28万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-22 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8635677
• 关键词: Address; Animal Model; Biological Models; Colorectal Cancer; Complex; Cyclin-Dependent Kinases; Development; Disease; Drosophila genus; Enhancers; Epidermal Growth Factor Receptor; Eukaryota; Future; Gene Expression; Genes; Genetic; Genetic Models; Genetic Screening; Genetic Transcription; Goals; Growth; Human; Knowledge; Link; Malignant Neoplasms; Mammalian Cell; Mammals; Maps; Mediator of activation protein; Modeling; Molecular; Oncogene Proteins; Organism; Pathway interactions; Phenotype; Physiological; Public Health; RNA Polymerase II; Receptor Signaling; Regulation; Research; Role; Signal Pathway; Signal Transduction; System; Trans-Activators; Transcription Coactivator; Work; cancer cell; cancer therapy; clinically significant; cyclin C; genetic analysis; in vivo; melanoma; mutant; novel; overexpression; public health relevance; transcription factor; tumorigenesis

DESCRIPTION (provided by applicant): Both CDK8 (Cyclin-Dependent Kinase 8) and its regulatory partner CycC (Cyclin C) are dysregulated in a variety of human cancers. CDK8 has been recently identified as an oncoprotein in melanoma and colorectal cancers, and CDK8 is amplified and/or overexpressed in more than half of these cancers. Depletion of CDK8 effectively blocks the growth of melanoma and colorectal cancer cells, which underscores the centrality of CDK8 in gene expression and demonstrates why CDK8 is considered an attractive and promising target for cancer treatment. However, how dysregulation of CDK8-CycC contributes to tumorigenesis, which is obviously of public health importance, remains poorly understood. To determine the normal and dysregulated functions of CDK8, it is essential to identify both the upstream regulators and the downstream effectors of CDK8-CycC. Unfortunately, analyses of function and regulation of CDK8 have been hampered by the lack of specific phenotypes or in vivo readouts for CDK8 activity in multicellular organisms. Because CDK8 and CycC are highly conserved in eukaryotes, we have solved this challenge by using Drosophila, which provides unparalleled sophistication in manipulating CDK8 activity in vivo. The long-term goal of our research is to elucidate the function and regulation of CDK8. Using Drosophila as an experimental system, we have carried out an unbiased genetic screen to identify important upstream regulators and downstream effectors of CDK8. We have identified ~70 enhancers and suppressors of the CDK8/CycC-specific phenotypes. Several candidate modifiers of these phenotypes are components of the EGFR (epidermal growth factor receptor) signaling pathway, dysregulation of which is well established in tumorigenesis of various human cancers. However, the potential link between CDK8 and EGFR signaling is novel and unexplored. Thus, the objective of this proposal is to further identify the specific mutant genes from our initial modifier genetic screen and as an example to illustrate our general approach to understand CDK8 in future studies, we will also determine how CDK8 interacts with the EGFR signaling pathway. By identifying additional genes whose products function either upstream or downstream of CDK8, our genetic analyses will enable us to elucidate the regulatory network of CDK8. In addition, this study will define the molecular mechanisms for functions of CDK8 in interacting with the EGFR signaling. These results will open up many new research directions, which will significantly advance our understanding of how dys- regulation of CDK8-CycC contributes to tumorigenesis. Because CDK8 and CycC are well conserved in eukaryotes, the genetic interactions and the underlying molecular mechanisms that we identify in Drosophila will provide a working model in human studies, and will significantly impact how we evaluate the efficacy of targeting CDK8 in treating human cancers in the future.

描述（由申请人提供）：CDK8（Cyclin依赖性激酶8）及其调节伴侣CYCC（Cyclin C）在各种人类癌症中均失调。 CDK8最近被确定为黑色素瘤和结直肠癌中的癌蛋白，并且在超过一半的癌症中，CDK8被放大和/或过表达。 CDK8的耗竭有效地阻断了黑色素瘤和结直肠癌细胞的生长，这突显了CDK8在基因表达中的中心性，并证明了为什么CDK8被认为是癌症治疗的有吸引力且有希望的靶标。但是，CDK8-CYCC的失调如何导致肿瘤发生，显然是公共健康重要性的，人们对肿瘤发生的理解仍然很差。为了确定CDK8的正常和失调函数，必须识别CDK8-CYCC的上游调节剂和下游效应子。不幸的是，由于缺乏特定的表型或多细胞生物中CDK8活性的体内读数，CDK8的功能和调节分析受到了阻碍。由于CDK8和CYCC在真核生物中是高度保守的，因此我们通过使用果蝇解决了这一挑战，果蝇在体内操纵CDK8活性时提供了无与伦比的复杂性。 我们研究的长期目标是阐明CDK8的功能和调节。使用果蝇作为实验系统，我们进行了一个公正的遗传筛选，以识别CDK8的重要上游调节剂和下游效应子。我们已经确定了CDK8/CYCC特异性表型的〜70个增强子和抑制剂。这些表型的几个候选修饰符是EGFR（表皮生长因子受体）信号传导途径的组成部分，其失调在各种人类癌症的肿瘤发生中已经很好地确定。但是，CDK8和EGFR信号之间的潜在联系是新颖且未开发的。因此，该提案的目的是从我们的初始修饰符遗传筛选中进一步识别特定的突变基因，并作为说明我们在未来研究中了解CDK8的一般方法的一个例子，我们还将确定CDK8如何与EGFR信号传导途径相互作用。 通过识别其产物在CDK8上游或下游功能的其他基因，我们的遗传分析将使我们能够阐明CDK8的调节网络。此外，这项研究将定义CDK8与EGFR信号相互作用的功能的分子机制。这些结果将打开许多新的研究方向，这将大大提高我们对CDK8-CYCC的DYS调节如何促进肿瘤发生的理解。由于CDK8和CYCC在真核生物中是良好的保守，因此我们在果蝇中鉴定的遗传相互作用和潜在的分子机制将在人类研究中提供一个工作模型，并将显着影响我们评估靶向CDK8在未来治疗人类癌症中的疗效。