Genomic Instability and Etiology of Estrogen Oncogenesis

描述(申请人提供)：DCIS和浸润性散发性乳腺癌(BC)的一个特征是其肿瘤细胞中高度的染色体不稳定(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。本研究的目的是在一种独特但相关的动物肿瘤模型--E诱导的仓鼠肾脏恶性肿瘤(HTK)中，确定E诱导CIN和非整倍体的机制。特异性目的1.确定在E诱导的HTK发育过程中持续过度表达/扩增的细胞周期成分(细胞周期蛋白E、D家族、B1)和调节因子(MDM2、DHFR)。这些基因/蛋白已被证明在体外系统中可诱导CIN，并且是E特异性AIM 2介导的c-myc/MYC过表达/扩增的下游靶点。为了确定在E诱导的HTK早期癌变过程中检测到的CIN是否是由于Cyclin.cdk复合体和其他细胞周期调节因子与纯化的HTK中心体及其蛋白结合而导致的中心体扩增所致。这些研究将为启动中心体扩增，从而启动CIN和非整倍体的机制提供证据，在非整倍体中，这些cyclin.cdk复合体和某些细胞周期调节器优先与特定的中心体蛋白结合，或与同一中心体蛋白上的不同位置结合。另一个目标是确定在HTK发育的早期阶段中心体扩增最早出现的时间。特定目的3.确定中心体扩增(数据在Sp.目的2)发生在CIN和非整倍体之前或作为它们的结果。这是阐明CIN和HTKs中非整倍体发生机制的关键。这一特定目的的一个主要目的是根据电疗持续时间和HTK病灶大小(体积)来确定早期HTK基因座CIN的最早时间出现；使用相同的中心体扩增最早出现的标准。第二个目标是利用相同的技术和HTK基因座的LCMD和DOP-PCR产生的DNA样本进行跨物种微阵列分析，以确定在HTK发育的早期阶段参与CIN或生长优势的候选基因。

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.