Breast cancer oncogenes on the 8p11 amplicon

描述（由申请人提供）：在前一个项目期间，我们对人乳腺癌细胞系和组织中的8 p11-p12扩增子进行了广泛分析，以鉴定和验证新型乳腺癌基因。通过对拷贝数增加和过度表达的统计分析，我们确定了21个基因的子集作为候选癌基因。接下来，我们直接测试了这些基因在人乳腺上皮细胞中的转化功能。从这些实验中，我们鉴定了在MCF-10A细胞中有效转化的四个基因和具有更适度转化功能的另外三个基因。鉴定的最有效的转化基因包括DDHD 2、SPFH 2、LSM 1和WHSC 1 L1，它们诱导生长因子非依赖性增殖、锚定非依赖性生长、侵袭能力和改变的基质胶形态发生。此外，我们确定了影响转化表型表达的基因组合。在这项工作的下一阶段，我们将进行实验，以了解这些癌基因的转化潜力的机制基础，我们将检查他们在体外人乳腺癌细胞中的转化功能，并在人体和小鼠乳腺上皮细胞在体内。下一个项目期的具体工作目标是：1）确定在MCF-10A细胞中诱导转化表型的七个基因是否直接转化，并确定转化在过表达癌基因的细胞中是常见还是罕见事件;（二）为了确定在人乳腺癌细胞系中扩增和过表达的8 p11区域的基因是否是这些乳腺癌细胞生长和存活所必需的，癌细胞与正常乳腺上皮细胞或没有扩增子的乳腺癌细胞相比。我们还将检验8 p11扩增子上的一些癌基因协同影响人乳腺癌细胞转化生长潜能的假设：3）确定8 p11癌基因过表达对人乳腺上皮细胞体内生长潜能的影响，并确定这些癌基因是否可以在体内转化小鼠乳腺上皮细胞; 4）检验WHSC 1 L1的短同种型的过表达改变组蛋白甲基化密码和基因表达谱的假设，导致细胞表现出肿瘤起始细胞的性质，包括增强的自我更新能力、癌症干细胞标志物的表达以及在培养物中形成乳腺球的能力。我们还将测试的假设，这些改变的表型的诱导需要一个完整的PWWP结构域，不需要SET结构域的蛋白质。明确证明新发现的8 p11转化基因是真正的乳腺癌癌基因，并阐明它们诱导细胞转化的机制，以开发针对这些癌基因的治疗策略是至关重要的。

DESCRIPTION (provided by applicant): In the previous project period, we performed an extensive analysis of the 8p11-p12 amplicon in human breast cancer cell lines and tissues to identify and validate novel breast cancer oncogenes. Using statistical analysis of copy number increase and over expression, we identified a subset of 21 genes as candidate oncogenes. Next, we directly tested the transforming function of these genes in human mammary epithelial cells. From these experiments, we identified four genes that are potently transforming in MCF-10A cells and three other genes with more modest transforming function. The most potently transforming genes identified, which include DDHD2, SPFH2, LSM1 and WHSC1L1, induce growth factor independent proliferation, anchorage-independent growth, invasive capacity, and altered morphogenesis in Matrigel. In addition, we identified gene combinations that effect the expression of transformed phenotypes. In the next phase of this work, we will perform experiments to understand the mechanistic basis for the transforming potential of these oncogenes, and we will examine their transforming function in human breast cancer cells in vitro, and in human and mouse mammary epithelial cells in vivo. The specific aims of the work in the next project period are: 1) To determine if the seven genes that induce transformed phenotypes in MCF-10A cells are directly transforming, and to determine if transformation is a common or a rare event in cells over expressing the oncogene; 2) To determine if the genes from the 8p11 region that are amplified and over expressed in human breast cancer cell lines are required for growth and survival of these breast cancer cells compared with normal mammary epithelial cells or breast cancer cells without the amplicon. We will also test the hypothesis that some oncogenes on the 8p11 amplicon cooperate to influence the transformed growth potential of human breast cancer cells; 3) To determine the influence of 8p11 oncogene over expression in the in vivo growth potential of human mammary epithelial cells, and to determine if these oncogenes can transform mouse mammary epithelial cells in vivo; 4) To test the hypothesis that over expression of the short isoform of WHSC1L1 alters the histone methylation code and gene expression profile, resulting in cells that exhibit properties of tumor initiating cells, including enhanced self-renewal capacity, expression of markers of cancer stem cells, and ability to form mammospheres in culture. We will also test the hypothesis that induction of these altered phenotypes requires an intact PWWP domain and does not require the SET domain of the protein. It is essential to demonstrate unequivocally that newly discovered 8p11 transforming genes are bone fide breast cancer oncogenes, and to elucidate the mechanism by which they induce cell transformation in order to develop therapeutic strategies that target these oncogenes.