Genomic Instability and Etiology of Estrogen Oncogenesis

描述（由申请人提供）：DCIS和浸润性散发性乳腺癌（BC）的标志性特征是其肿瘤细胞中高水平的染色体不稳定性（CIN）和非整倍体。然而，到目前为止，CIN和非整倍体与雌激素（E）的作用没有直接关系。本提案的目的是确定E在一个独特但相关的动物肿瘤模型（E诱导的仓鼠肾恶性肿瘤（HTK））中诱导CIN和非整倍体的机制。具体目标1.确定在E诱导的HTK发育过程中表现出持续过表达/扩增的细胞周期组分（细胞周期蛋白E、D家族、B1）和调节剂（MDM 2、DHFR）。这些基因/蛋白质已被证明在体外系统中引发CIN，并且是由大肠杆菌介导的c-myc/MYC过表达/扩增的下游靶标。具体目标2.为了确定在早期E诱导的HTK肿瘤发生过程中检测到的CIN是否是由cyclin、cdk复合物和其他细胞周期调节剂与纯化的HTK中心体及其蛋白结合而导致的中心体扩增引起的。这些研究将为启动中心体扩增的机制提供证据，从而为CIN和非整倍体提供证据，其中这些细胞周期蛋白、cdk复合物和某些细胞周期调节剂优先结合特定的中心体蛋白，或结合同一中心体蛋白上的不同位点。另一个目标是确定在HTK发育的早期阶段中心体扩增的最早时间出现。具体目标3.确定中心体扩增（数据在Sp. Aim 2中进行）是否发生在CIN和非整倍体之前或作为其结果。这是阐明HTK中CIN和非整倍体机制的关键问题。这一特定目标的主要目的是根据E治疗的持续时间和HTK病灶大小（体积）确定早期HTK基因座中CIN的最早时间表现;使用与中心体扩增最早出现相同的标准。第二个目标是鉴定在HTK发育的最早阶段参与CIN或生长优势的候选基因，采用相同的技术和从HTK基因座的LCMD和DOP-PCR产生的DNA样品进行跨物种微阵列分析。

DESCRIPTION (provided by applicant): A hallmark characteristic of DCIS and invasive sporadic breast cancer (BC) is the high level of chromosomal instability (CIN) and aneuploidy in its tumor cells. However, CIN and aneuploidy have not been, until now, directly related to estrogen (E) action. The goal of this proposal is to determine the mechanism whereby E elicits CIN and aneuploidy in a unique, but relevant animal tumor model, the E-induced malignant tumors in the hamster kidney (HTK). SPECIFIC AIM 1. To determine the cell cycle components (cyclins E, D family, B1) and modulators (MDM2, DHFR) which exhibit sustained overexpression/amplification during E-induced HTK development. These genes/proteins have been shown to elicit CIN in in-vitro systems, and are downstream targets of c-myc/MYC overexpression/amplification mediated by E. SPECIFIC AIM 2. To determine whether the CIN detected during early E-induced HTK oncogenesis is caused by centrosome amplification resulting from the binding of cyclin.cdk complexes and other cell cycle modulators to purified HTK centrosomes and their proteins. These studies will provide evidence for a mechanism for initiating centrosome amplification, and hence CIN and aneuploidy in which these cyclin.cdk complexes and certain cell cycle modulators bind preferentially to specific centrosome proteins, or to different sites on the same centrosome protein. Another goal is to determine the earliest temporal appearance of centrosome amplification during early stages of HTK development. SPECIFIC AIM 3. To determine whether centrosome amplification (data performed in Sp. Aim 2) occurs before CIN and aneuploidy or as a consequence of them. This is a key issue in elucidating the mechanism of CIN and aneuploidy in HTKs. A major goal of this specific aim is to determine the earliest temporal appearance of CIN in early HTK loci, based on duration of E-treatment and HTK foci size (volume); using the same criteria for the earliest appearance of centrosome amplification. A second goal is to identify candidate genes that are involved in either CIN or growth advantage in the earliest stages of HTK development, employing the same techniques and DNA samples generated from LCMD and DOP-PCR of HTK loci to be subjected to cross-species mircoarray analysis.