Molecular Basis of Aneuploidy

非整倍体的分子基础

• 批准号: 7030179
• 负责人: DEBANANDA PATI
• 金额: $ 23.25万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-07 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7030179
• 关键词: aneuploidy; breast neoplasms; cell cycle; cell cycle proteins; chromatin; chromosome movement; endopeptidases; gene expression; genetic terminator element; genetic transcription; genetically modified animals; hormone related neoplasm /cancer; laboratory mouse; mammary gland; molecular oncology; neoplasm /cancer genetics; nucleoproteins; p53 gene /protein; steroid hormone

DESCRIPTION (provided by applicant): This proposal focuses on an important but unexplored problem - how steroid hormones, which are well known risk factors, interact with p53 mutations to produce aneuploidy and malignancy, and how the chromosomal segregation protein Separase is involved? Our sex-steroid dependent p53-mice preneoplastic breast cancer model allows a unique approach to this problem. In this model, steroidal induction in p53 mutant mammary glands results in chromosomal instability, aneuploidy and tumor formation analogous to that seen in majority of human breast cancers. We propose a paradigm that there is a set of proteins whose deregulation promotes aneuploidy (termed PR AN; Promoter of Aneuploidy) including chromosomal instability which results in loss or gain of whole or parts of chromosomes, and that PRAN proteins are interactively regulated by steroid hormones and the tumor suppressor p53. Our published and new preliminary data provide the first evidence that steroid hormones play a role in the regulation of mitotic proteins involved in sister chromatid cohesion and separation. We propose that the combined effect of mutation of the tumor suppressor p53 and signaling by steroid hormones produces aneuploidy in breast cancer by affecting expression of key proteins involved in chromosomal separation. We focuses on the elements that regulate chromosomal segregation, particularly sister chromatid cohesion/separation proteins, as candidate PRAN proteins, since chromosome missegregation during mitosis can lead to aneuploidy. A key gene in this analysis is ESPL1, which encodes an endopeptidase called Separase that separates joined sister chromatids by cleaving cohesin Rad21/SCC1/MCD1 during the metaphase to anaphase transition. The hypothesis is that hormonal stimulation of p53 null mouse mammary glands results in misexpression of the ESPL1 gene, thus promoting aneuploidy and breast cancer formation. This proposal applies in vivo transplantation of p53 mutant and wild type (WT) mammary cells that are stably transfected with ESPL1, and an ESPL1 transgenic mice model to test the PRAN paradigm following hormone treatment. Steroid and p53 regulation of ESPL1 at the transcriptional level is studied by characterizing the ESPL1 promoter region. These objectives will be accomplished by pursuing two specific aims: 1) Functional role of Separase overexpression in aneuploidy, and 2) Transcriptional regulation of ESPL1 gene expression. The proposed study not only elucidate underlying mechanisms of hormone-induced aneuploidy, a fundamental unresolved question in cancer biology, but also likely to identify a new class of proteins that are responsible for chromosomal instability and breast cancer progression.

描述（由申请人提供）：该提案侧重于一个重要但未探索的问题-类固醇激素是众所周知的风险因素，如何与p53突变相互作用以产生非整倍体和恶性肿瘤，以及染色体分离蛋白Separase如何参与？我们的性类固醇依赖性p53-小鼠癌前乳腺癌模型允许一种独特的方法来解决这个问题。在该模型中，p53突变乳腺中的类固醇诱导导致染色体不稳定性、非整倍性和肿瘤形成，类似于在大多数人乳腺癌中所见。我们提出了一个范例，有一组蛋白质，其失调促进非整倍性（称为PR AN;非整倍性启动子），包括染色体不稳定性，导致整个或部分染色体的丢失或获得，并且PRAN蛋白质受类固醇激素和肿瘤抑制因子p53的相互调节。我们发表的和新的初步数据提供了第一个证据，类固醇激素在调节有丝分裂蛋白质参与姐妹染色单体的凝聚和分离中发挥作用。我们认为，肿瘤抑制基因p53的突变和类固醇激素的信号传导的联合作用通过影响参与染色体分离的关键蛋白的表达而在乳腺癌中产生非整倍体。我们专注于调节染色体分离的元素，特别是姐妹染色单体凝聚/分离蛋白，作为候选PRAN蛋白，因为有丝分裂过程中染色体的错误分离可能导致非整倍性。在这项分析中的一个关键基因是ESPL 1，它编码一种称为Separase的内肽酶，在中期到后期的过渡期间通过切割粘着蛋白Rad 21/SCC 1/MCD 1来分离连接的姐妹染色单体。该假说认为，激素刺激p53基因缺失小鼠乳腺导致ESPL 1基因的错误表达，从而促进非整倍体和乳腺癌的形成。该提议应用用ESPL 1稳定转染的p53突变体和野生型（WT）乳腺细胞的体内移植，以及ESPL 1转基因小鼠模型来测试激素处理后的PRAN范例。类固醇和p53在转录水平上的调控ESPL 1的研究通过表征ESPL 1启动子区域。这些目标将通过追求两个特定目标来实现：1）Separase过表达在非整倍体中的功能作用，和2）ESPL 1基因表达的转录调节。这项研究不仅阐明了乳腺癌诱导的非整倍体的潜在机制，这是癌症生物学中一个基本的未解决的问题，而且还可能确定一类新的蛋白质，这些蛋白质负责染色体不稳定和乳腺癌进展。