Breast cancer oncogenes on the 8p11 amplicon.

描述(申请人提供)：涉及染色体8p11-p12的焦点扩增发生在大约15%的人类乳腺癌中。长期以来，成纤维细胞生长因子受体1(FBFR1)基因一直被认为是该基因的最佳候选癌基因。我们实验室培养的三个乳腺癌细胞系SUM-44、SUM-52和SUM-225具有以8p11.2染色体为中心的重叠扩增。FGFR1在其中两个细胞系中扩增，但只在其中一个细胞系中过度表达。另一个定位于该区域的基因，转化相关卷曲蛋白1(TACC1)，最近被证明在一些乳腺癌细胞中过度表达，并在NIH3T3细胞中具有转化活性。TACC1在我们的所有三个细胞系中都被扩增和过度表达。除FGFR1/TACC1外，SUM-52和SUM-225细胞可能各有不同的扩增片段，分别以8p12和8q11.1为中心。这些区域包含几个高度过度表达的基因。因此，这项建议的主要目的是检测8p11-p12扩增子在人类乳腺癌中的预后和预测意义，并确定其中可能是开发新疗法的良好靶点的基因。该项目的具体目标是：1)利用Southern blotting完成对SUM-44、SUM-52和SUM-225细胞系中8p11-p12扩增子的精细定位，使用已知映射到每一系中的基因扩增区域的探针来完成；2)通过Northern印迹和RT-PCR检测扩增的基因在每个细胞系中的表达水平；3)利用组织微阵列确定在乳腺癌标本中扩增8p12-8q11扩增子的不同区域以及特定候选乳腺癌基因的预测和/或预后意义，4)通过将候选基因导入永生化的人乳腺上皮细胞，并通过反义技术下调乳腺癌细胞中过度表达的基因，以检测在三种乳腺癌细胞系中扩增和过度表达的基因的机制意义。因此，这些研究的目的是为乳腺癌的一个重要子集定义新的、更好的预后和预测标记物，并识别因果相关基因，其产物可能是新疗法的良好靶点。

DESCRIPTION (provided by applicant): Focal amplifications involving chromosome 8p11-p12 occur in approximately 15% of human breast cancers. The fibroblast growth factor receptor 1 (FBFR1) gene has long been considered to be the best candidate oncogene at that locus. Three breast cancer cell lines developed in our lab; SUM-44, SUM-52 and SUM- 225, have overlapping amplicons centered around chromosome 8p11.2. FGFR1 is amplified in two of these cell lines, but is over expressed in only one of them. A second gene that maps to this region, transformation associated coiled-coiled protein 1 (TACC1), has recently been shown to be over expressed in some breast cancer cells and to have transforming activity in NIH3T3 cells. TACC1 is amplified and over expressed in all three of our cell lines. In addition to the FGFR1/TACC1 locus, SUM-52 and SUM-225 cells may each have distinct amplicons that center around 8p12 and 8q11.1 respectively. These regions contain several genes that are highly over expressed. Therefore, the broad aim of this proposal is to examine the prognostic and predictive significance of the 8p11-p12 amplicon in human breast cancer, and to identify genes therein that may be good targets for the development of novel therapeutics. The specific aims of this project are: 1) To complete the fine mapping of the 8p11-p12 amplicon in the SUM-44, SUM-52, and SUM-225 cell lines by Southern blotting using probes for genes known to map to the region of gene amplification in each line, 2) To examine the expression levels of the amplified genes in each cell line by northern blot and RT-PCR, 3) To determine the predictive and/or prognostic significance of amplification of distinct regions of the 8p12-8q11 amplicon, and of specific candidate breast cancer genes, in breast cancer specimens using tissue micro arrays, 4) To test the mechanistic significance of genes found to be amplified and over expressed in the three breast cancer cell lines by transduction of candidate genes into immortalized human mammary epithelial cells, and by antisense techniques to down-regulate over expressed genes in breast cancer cells. Thus, these studies are aimed at defining new and better prognostic and predictive markers for an important subset of breast cancer, and at identifying causally relevant genes the products of which could be good targets for novel therapeutics.