TERT transcriptional deregulation in thyroid cancer progression

项目摘要/摘要 TERT转录失控与甲状腺癌进展 我在研究生期间接受了甲状腺癌遗传学方面的培训，在此期间我确定了生殖系启动子。 与甲状腺癌易感性相关的变异。在我的博士后岁月里，我领导了一个项目，揭示了关键 低分化(PDTC)和间变性(ATC)甲状腺的体细胞基因组和转录特征 癌症。我们报道TERT(端粒酶逆转录酶)基因启动子的突变是 通常致命的PDTC和ATC中最普遍的基因改变，并构成良好的疾病生物标志物 严肃性。尽管人们普遍认为TERT启动子突变激活了基因转录，但特异性的 这些变化的机制和生物效应在很大程度上仍不清楚。这促使我研究了 TERT转录失控在甲状腺癌进展中的作用，这是我K22提案的主题。 我相信这个项目有很大的潜力，将有助于我建立自己的实验室。为此，我已经把 一个咨询委员会和合作者将共同分享他们在以下领域的专业知识和资源 转录调控、染色质生物学和基因工程小鼠癌症模型，以及 职业建议，而我则在寻求获得终身教职的职位。这份提案概述了一种全面的方法 TERT启动子突变在端粒酶转录失控和甲状腺中的作用 癌症进展。这个项目的第一个目标是识别差异结合的转录复合体。 TERT突变体与野生型启动子的比较，为此，我提出了一个双重调控模型。首先，我们描述 实验确定特定的ETS家族成员在TERT突变启动子重新激活中的作用，我们 Believe与其他疾病背景下报告的不同。我们还将评估MAPK的效果 构成信号，甲状腺肿瘤的标志，在ETS介导的TERT表达中。第二，我们的目标是推出 CTCF基因组绝缘子通过长程增强子对TERT转录抑制的影响 启动子相互作用。我们有初步数据表明，ETS和CTCF因素竞争TERT 分别在突变和野生型条件下结合启动子，对基因转录产生相反的影响。 我们的第二个目标是鉴定我们已经建立的第一个TERT突变启动子小鼠模型 通过CRISPR敲入等效鼠基因座。我们的初步数据表明，TERT促进甲状腺 癌症进展与甲状腺特异性致癌等位基因BRAFV600E相结合。我们还将评估哪些 信号通路参与TERT诱导的甲状腺肿瘤，以及它们是否造成独特的脆弱性 可以在治疗上加以利用。总体而言，我的目标是让自己成为一名独立的调查员 甲状腺癌生物学和转录调控领域，以及K22拨款的授予将极大地 促进这一过渡。

PROJECT SUMMARY / ABSTRACT TERT transcriptional deregulation in thyroid cancer progression I trained in thyroid cancer genetics in my graduate studies, during which time I identified germline promoter variants conferring thyroid cancer susceptibility. In my postdoctoral years I led a project that revealed the key somatic genomic and transcriptomic hallmarks of poorly differentiated (PDTC) and anaplastic (ATC) thyroid cancers. We reported that mutations in the promoter of TERT (telomerase reverse transcriptase) gene are the most prevalent genetic alterations in often fatal PDTCs and ATCs, and constitute good biomarkers of disease severity. Although it is widely accepted that TERT promoter mutations activate gene transcription, the specific mechanisms and biological effects of these alterations remain largely unknown. This prompted me to study the role of TERT transcriptional deregulation in thyroid cancer progression, which is the subject of my K22 proposal. I believe this project has great potential and will facilitate my setting up my own lab. To this end, I have put together an advisory committee and collaborators who will share their expertise and resources in the fields of transcriptional regulation, chromatin biology and genetically engineered mouse models of cancer, as well as career advice, while I seek to secure a tenure-track position. This proposal outlines a comprehensive approach to characterizing the role of TERT promoter mutations in telomerase transcriptional deregulation and thyroid cancer progression. The first aim of this project is to identify the transcriptional complex that differentially binds TERT mutant vs. wildtype promoter, and to this end I propose a dual regulation model. First, we describe experiments to define the role of specific ETS family members in TERT mutant promoter reactivation, which we believe are distinct from those reported in other disease contexts. We will also evaluate the effect of MAPK constitutive signaling, a hallmark of thyroid tumors, in ETS-mediated TERT expression. Second, we aim to unveil the influence of the CTCF genome insulator on TERT transcriptional repression through long-range enhancer- promoter interactions. We have preliminary data suggesting that ETS and CTCF factors compete for TERT promoter binding in mutant and wildtype conditions, respectively, inducing opposite effects on gene transcription. Our second aim is to characterize the first Tert mutant promoter mouse model, which we have already generated via CRISPR knock-in of the equivalent mouse locus. Our preliminary data suggest that Tert promotes thyroid cancer progression in combination with a thyroid-specific oncogenic BrafV600E allele. We will also assess which signaling pathways are involved in Tert-induced thyroid tumors, and whether they create unique vulnerabilities that can be exploited therapeutically. Overall, my goal is to establish myself as an independent investigator in the field of thyroid cancer biology and transcriptional regulation, and the awarding of the K22 grant will greatly facilitate this transition.