Tracing the origins of chromosomal translocations in prostate cancer

摘要 染色体易位是癌症进展的标志。这些易位通常导致基因 融合，一种常见的致癌基因激活机制。直到最近，反复出现的基因融合 主要与血液恶性肿瘤（白血病和淋巴瘤）和软组织肿瘤相关 （肉瘤），但很少与常见的上皮癌。这一观点随着 前列腺癌中涉及ETS家族基因的复发性基因融合。在ETS家族基因融合体中， 涉及雄激素调节基因TMPRSS2的5 '非翻译区与TMPRSS2-ERG融合物 ERG基因是最常见的，在大约50%的前列腺癌中发现。的发展 下一代基于测序的方法，如RNA-Seq和配对末端全基因组测序， 加速了前列腺癌基因融合的发现。然而， 染色体易位的形成和细胞类型特异性还远不清楚。我们的建议旨在 在染色体易位的快速发现和我们对染色体易位的有限理解之间架起了差距。 导致其形成的机制。在我们最近的研究中，我们证明了雄激素信号传导 诱导TMPRSS2和ERG基因座之间的染色体接近，并促进TMPRSS2和ERG基因座的形成。 TMPRSS2-ERG基因融合，当受到导致DNA双链断裂的试剂时。这些 结果为人类前列腺癌中基因融合的发生提供了一个概念框架。在特定 目标1，我们建议采用下一代测序技术来鉴定全基因组染色体相互作用 由雄激素信号传导介导。导师在生产技术方面的专业知识将有助于候选人 获得必要的技能，以实现目标1。有趣的是，我们发现了新的复发性突变， 雄激素受体AR协作因子FOXA 1，其在147例前列腺癌中的5例（3.4%）中突变。 对一个代表性突变的初步功能研究表明，突变的FOXA 1破坏雄激素 信号传导并增加增殖。在具体目标2中，我们建议研究FOXA 1突变对 调节AR信号传导和相互作用体。目标2是目标1的逻辑延伸， 独立相位（R00）。实现这两个目标将为我们提供一个全面的 了解前列腺细胞的三维基因组结构，AR如何调节这种结构， 架构，AR协作因素的影响突变，以及重要的是这如何影响 基因融合的形成。虽然空间邻近对于染色体易位是必要的，但它不是 足够了。DNA断裂与空间邻近协同作用以促进染色体易位。在具体目标3中， 我们将研究炎症介导的NF-κ B通路活化在DNA断裂形成中的作用 和ETS基因融合的研究进展。成功完成本提案中概述的目标将 提高我们对前列腺癌中染色体易位起源的理解， 对理解和治疗癌症的影响，并可能提供关于癌症的一般病因学的建议。 人类前列腺癌。这些项目是根据我的原始想法构思的。Chinnaiyan博士 他对我的职业目标给予了全力支持，并鼓励我把这些项目带到我的 未来的独立实验室

Abstract Chromosomal translocations are a hallmark of cancer progression. These translocations often result in gene fusions, a common mechanism for oncogene activation. Until recently, recurrent gene fusions were predominantly associated with hematological malignancies (leukemias and lymphomas) and soft tissue tumors (sarcomas), but were rarely linked to common epithelial carcinomas. This view changed with the discovery of recurrent gene fusions involving ETS family genes in prostate cancer. Among the ETS family gene fusions, the TMPRSS2-ERG fusions involving the 5’untranslated region of androgen-regulated gene TMPRSS2 with the ERG gene are the most common and found in approximately 50% of prostate cancers. The development of next generation sequencing based approaches like RNA-Seq and paired-end whole-genome sequencing have accelerated the discoveries of gene fusions in prostate cancer. However, the mechanisms underlying the formation and cell type specificities of chromosomal translocations are far from clear. Our proposal aims to bridge the gap between the rapid discovery of chromosomal translocations and our limited understanding of the mechanisms leading to their formation. In our recent study, we demonstrate that androgen signaling induces chromosomal proximity between TMPRSS2 and ERG loci, and facilitates the formation of the TMPRSS2-ERG gene fusion when subjected to an agent that causes DNA double strand breaks. These results provide a conceptual framework for the genesis of gene fusions in human prostate cancer. In specific aim 1, we propose to employ next-generation sequencing to identify genome-wide chromosomal interactions mediated by androgen signaling. The mentor’s expertise in throughput technologies will help the candidate acquire the necessary skill-set to accomplish aim 1. Interestingly, we identified novel recurrent mutations in the androgen receptor AR collaborating factor FOXA1, which is mutated in 5 of 147 (3.4%) prostate cancers. Preliminary functional studies on one representative mutation revealed that mutated FOXA1 disrupts androgen signaling and increases proliferation. In specific aim 2, we propose to study the effect of FOXA1 mutations in regulating AR signaling and interactome. Aim 2, a logical extension of aim 1 will be pursued during the independent phase (R00). Accomplishment of these two aims will provide us with a comprehensive understanding of the three dimensional genomic architecture of prostatic cells, how AR regulates this architecture, the influence mutations in AR collaborating factors, and importantly how this impacts the formation of gene fusions. While spatial proximity is necessary for chromosomal translocations, it is not sufficient. DNA breaks synergize with spatial proximity to fuel chromosomal translocations. In specific aim 3, we will study the role of inflammation mediated activation of NF-κB pathway in the formation of DNA breaks and ETS gene fusions in prostate cancer. Successful completion of the aims outlined in this proposal will improve our understanding of the origins of chromosomal translocations in prostate cancer, may have broader implications for understanding and treating cancer and may provide suggestions as to the general etiology of human prostate cancer. These projects have been conceived based on my original ideas. Dr. Chinnaiyan has extended his full support towards my career goals and has encouraged me to take these projects to my independent lab in the future.