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）：该提案着重于一个重要但未开发的问题 - 类固醇激素是如何与p53突变相互作用以产生非整倍性和恶性肿瘤的相互作用，以及染色体分离蛋白分离酶如何涉及？我们的性类甾体依赖性p53-鼠后乳腺癌模型允许解决此问题的独特方法。在该模型中，p53突变体乳腺中的类固醇诱导会导致染色体不稳定性，非整倍性和肿瘤形成类似于大多数人乳腺癌。我们提出了一个范式，即有一组蛋白质的放松管制促进非整倍性（称为PR an; emploidy的启动子），包括染色体不稳定性，从而导致染色体的整体或部分损失或增益，而Pran蛋白质的整体或部分则由pran蛋白质与类固醇荷尔蒙和tumor tumor Suppressor p53相互作用。我们已发表的新初步数据提供了第一个证据，表明类固醇激素在调节涉及姐妹染色单体内聚和分离的有丝分裂蛋白中起作用。我们提出，肿瘤抑制剂p53突变和类固醇激素的信号的综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性。我们专注于调节染色体隔离的元素，尤其是姐妹染色质被凝聚/分离蛋白作为候选PRAN蛋白，因为有丝分裂过程中染色体错误分泌可能会导致非整倍倍倍倍倍相。该分析中的一个关键基因是ESPL1，它编码一种称为分离酶的内肽酶，该酶通过在中期期间将粘着蛋白RAD21/SCC1/MCD1切割到后期过渡到后期过渡，从而分离了姐妹染色质。假设是p53无效小鼠乳腺的激素刺激会导致ESPL1基因的表现，从而促进非整倍性和乳腺癌的形成。该建议应用于稳定地用ESPL1转染的p53突变型和野生型（WT）乳腺细胞的体内移植，以及在激素处理后测试PRAN范式的ESPL1转基因小鼠模型。通过表征ESPL1启动子区域来研究转录水平上ESPL1的类固醇和p53调节。这些目标将通过追求两个具体目标来实现：1）分离酶过表达在非整倍性中的功能作用，以及2）ESPL1基因表达的转录调节。拟议的研究不仅阐明了激素诱导的非整倍性的潜在机制，癌症生物学中的基本未解决的问题，而且很可能鉴定出一种新的蛋白质，这些蛋白质是染色体不稳定性和乳腺癌进展的原因。