Molecular basis of MED12 in the pathogenesis of uterine fibroids

MED12在子宫肌瘤发病机制中的分子基础

基本信息

批准号：
9927654
负责人：
THOMAS G BOYER
金额：
$ 31.03万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9927654
关键词：
Accounting Address Agonist Autologous Benign Binding Biochemical Cell division Cells ChIP-seq Chemicals Common Neoplasm DNA Polymerase II DNA-Directed RNA Polymerase Development Disease Enhancers Enzyme Kinetics Etiology Fibroid Tumor Functional disorder Gene Expression Genes Genetic Genetic Transcription Genetic Transformation Glucocorticoid Receptor Growth Gynecologic Habitual Abortion Hemorrhage In Vitro Infertility Link Mediator of activation protein Medical Molecular Mutate Mutation Neoplasms Operative Surgical Procedures Pathogenesis Pathogenicity Pathologic Pathway interactions Pelvic Pain Peptides Pharmacology Phenotype Phosphorylation Phosphotransferases Premature Labor Process RNA Receptor Signaling Recurrence Role Seeds Signal Pathway Signal Transduction Site Somatic Mutation Testing Therapeutic Therapeutic Intervention Tumor Suppressor Proteins Uterine Fibroids Woman beta catenin cell transformation clinically significant cyclin C epigenomics genome-wide in vivo insight loss of function mutation mutant myometrium new therapeutic target novel paralogous gene personalized medicine programs reproductive restoration stem cells transcription factor transcriptome sequencing transcriptomics tumor tumorigenesis tumorigenic

项目摘要

PROJECT SUMMARY/ABSTRACT Uterine leiomyomas (LM; fibroids) are monoclonal neoplasms of the myometrium (MM) and represent the most frequent tumors in women worldwide. Although benign, they nonetheless account for significant gynecologic and reproductive dysfunction. As no long-term non-invasive treatment option exists for LM, deeper insight regarding tumor etiology is key to the development of newer targeted therapies. Accordingly, this proposal is impactful as it suggests an etiologic basis for the predominant LM subtype and further offers proof of concept for therapeutic intervention involving new druggable targets in this specific genetic setting. LM arise from the genetic transformation of a single MM stem cell (SC) into a tumor initiating cell (LM SC) that seeds and sustains fibroid growth through asymmetric cell divisions. Heretofore, the dominant drivers of cell transformation have been largely identified. The most prevalent among these, accounting for ~70% of LM, are recurrent somatic mutations in the gene encoding the MED12 subunit of Mediator, a multiprotein signal processor through which regulatory information conveyed by gene- specific transcription factors is transduced to RNA polymerase II (Pol II). However, the impact of these mutations on MED12 function and the molecular basis for their tumorigenic potential remain unknown. Herein, we show that LM-linked mutations in MED12 disrupt its ability to activate Cyclin C (CycC)-dependent kinase 8 (CDK8) in Mediator, leading to reduced site-specific RNA Pol II phosphorylation and global gene dysregulation. We also identify genetic programs uniquely dysregulated in MED12-mutant fibroids, leading us to hypothesize that Mediator kinase disruption as a consequence of MED12 mutations elicits transcriptional reprogramming and altered signaling sufficient to drive MM SC transformation. We further hypothesize that MED12-mutant LM are therapeutically susceptible to reactivation of CDK8 or pharmacologic modulation of uniquely dysregulated signaling pathways. To test these hypotheses we will: (1) Establish the pathogenic role of Mediator kinase disruption in MED12-mutant LM. We will ask if genetic or chemical disruption of CDK8 (or its paralog CDK19) in Mediator can induce fibrotic transformation of MM SCs and, conversely, if WT MED12 can restore CDK8/19 kinase activity and suppress the fibrotic phenotype of MED12-mutant LM SCs; (2) Elucidate the pathogenic mechanism of Mediator kinase disruption in MED12- mutant LM. We will define the biochemical basis by which MED12 mutations disrupt CycC-CDK8/19 kinase activity and employ an integrated genome-scale approach to acquire the unique transcriptomic and epigenomic profiles of MED12 WT and mutant LM SCs; (3) Examine the therapeutic implications of Mediator kinase disruption in MED12-mutant LM. We will ask if reactivation of CDK8/19 or pharmacologic manipulation of signaling pathways uniquely dysregulated in MED12-mutant LM SCs can reverse their fibrotic phenotype. We expect these studies to significantly impact personalized treatment of women with LM.

项目摘要/摘要子宫平滑肌瘤（LM；肌瘤）是肌层（MM）的单克隆肿瘤，并表示全球女性最常见的肿瘤。尽管良性，但他们仍然说明了重要妇科和生殖功能障碍。由于LM不存在长期无创治疗方案，因此关于肿瘤病因的更深入的见解是开发较新的靶向疗法的关键。因此，该提案具有影响力，因为它建议了主要的LM亚型的病因学基础并进一步提供了涉及这种特定毒品目标的治疗干预措施的概念证明遗传环境。 LM是由单个MM干细胞（SC）转化为肿瘤的遗传转化引发通过不对称细胞分裂的种子和维持肌瘤生长的细胞（LM SC）。迄今为止，已经确定了细胞转化的主要驱动因素。最普遍的其中，占LM的约70％是编码Med12的基因中的复发体突变介体的亚基，一种多蛋白信号处理器的亚基，基因传达的调节信息特定的转录因子被转导到RNA聚合酶II（POL II）。但是，这些影响 Med12功能的突变及其致瘤潜力的分子基础仍然未知。在此处，我们表明，Med12中的LM连接突变破坏了其激活Cyclin C（CYCC）依赖性的能力介体中的激酶8（CDK8），导致位点特异性RNA POL II磷酸化和全局基因失调。我们还确定在Med12突变肌瘤中唯一失调的遗传程序，导致我们假设由于Med12突变引起的介体激酶破坏转录重新编程和改变的信号传导足以驱动MM SC转换。我们进一步假设Med12-突变的LM在治疗上容易受到CDK8或独特失调信号通路的药理调制。为了检验这些假设，我们将：（1）在Med12突变LM中建立介体激酶破坏的致病作用。我们会问遗传还是介体中CDK8的化学破坏（或其旁系同源物CDK19）可以诱导MM SC的纤维化转化而且，相反，如果WT Med12可以恢复CDK8/19激酶活性并抑制纤维化表型 MED12突变LM SCS；（2）阐明Med12-中介体激酶破坏的致病机制突变lm。我们将定义Med12突变破坏Cycc-CDK8/19激酶的生化基础活动并采用综合基因组尺度方法来获取独特的转录组和表观基因组学 Med12 wt和突变LM SC的轮廓；（3）检查介质激酶的治疗意义 Med12突变的LM中断。我们将询问CDK8/19的重新激活还是对在Med12突变的LM SC中唯一失调的信号通路可以逆转其纤维化表型。我们预计这些研究将显着影响LM女性的个性化治疗。