An in vivo model for CCNE1 amplified tumorigenesis

项目摘要 高级别浆液性卵巢癌（HGSOC）是卵巢癌中最具破坏性的癌症相关疾病之一， 美国的它是最致命的妇科恶性肿瘤和公共卫生负担。从历史上看， 认为卵巢肿瘤起源于卵巢表面上皮。最近，这一思想流派 由于在女性输卵管（FT）中发现早期HGSOC前体， 由于BRCA 1或BRCA 2基因突变导致HGSOC的风险。大多数病例局限于 FT的流苏状末端，包括浆液性输卵管上皮内癌（STIC）作为主要前体 损伤。HGSOC的癌症基因组图谱显示，大约50%的HGSOC在HGSOC中携带突变。 BRCA基因或DNA修复的同源重组（HR）途径中的其它基因。这些肿瘤 倾向于对化疗和聚（ADP-核糖）聚合酶（PARP）抑制剂反应良好。可惜 其余50%的HGSOC通常是HR熟练的，对标准治疗反应不佳， 与更糟糕的结果相关。具有CCNE 1基因扩增的HGSOC代表了显著的 这些高HR肿瘤的一部分。CCNE 1产生一种蛋白质，细胞周期蛋白E1，它控制细胞分裂， 也会破坏细胞的基因组。患有CCNE 1扩增肿瘤的女性不太可能 对PARP抑制剂有反应，因此代表了一个重要的未满足的需求。虽然有一些药物 目前在其他实体癌中正在开发可能在CCNE 1扩增的HGSOC中有效的， 目前还没有动物模型来研究细胞周期蛋白E1在HGSOC中的功能或候选抑制剂的功效。 本申请描述了我们开发模拟人类疾病的小鼠模型的目标，从而 为检测新型细胞周期蛋白E1抑制剂提供了临床前平台。我们将构建转基因小鼠， Ccne 1基因可以在我们想要的时间和地点被精确地激活。使用成熟的技术，我们 将改造小鼠，使其在FT分泌性上皮细胞（祖细胞）中高水平表达细胞周期蛋白E1。 关于HGSOC我们在这些动物的产生和分析方面非常有经验。重要的是，TP 53是 在人类HGSC中总是有缺陷的，并且其缺失似乎是细胞耐受存在的条件。 过量的细胞周期蛋白E1。因此，我们的模型将纳入突变体TP 53的表达。实验室研究 提示这两种遗传改变--Ccne 1过度表达和Tp 53突变--将足以 产生肿瘤。然而，也有可能小鼠需要额外的突变才能发育 模拟人类疾病的HGSC。在资助的第二部分，我们使用了FT基因筛查的数据， 从数千个癌症基因组中提取细胞和信息，以寻找可能与CCNE 1合作的基因， 可以添加到老鼠身上。这项研究可能会为投入的努力提供高回报，因为老鼠 将提供一个持久的资源-一旦模型建立起来，它可以在许多设置中使用， 强大的持续平台，用于开发CCNE 1抑制剂。

PROJECT SUMMARY High-grade serous ovarian carcinoma (HGSOC) is one of the most devastating cancer-related diseases in the United States. It is the deadliest gynecological malignancy and a public health burden. Historically, it was thought that ovarian tumors arise from the ovarian surface epithelium. Recently, this school of thought has been challenged by the finding of early HGSOC precursors in the fallopian tubes (FT) of women at increased risk of developing HGSOC due to mutations in the BRCA1 or BRCA2 genes. Most cases were localized to the fimbriated end of the FT and included serous tubal intraepithelial carcinoma (STIC) as the dominant precursor lesion. The Cancer Genome Atlas of HGSOC showed that approximately 50% of HGSOCs harbor mutations in the BRCA genes or other genes in the homologous recombination (HR) pathway of DNA repair. These tumors tend to respond well to chemotherapy and poly (ADP-ribose) polymerase (PARP) inhibitors. Unfortunately, the remaining 50% of HGSOC are often HR-proficient, do not respond well to standard treatment, and are associated with worse outcomes. HGSOCs with amplification of the CCNE1 gene represent a significant fraction of these HR-proficient tumors. CCNE1 makes a protein, cyclinE1, that controls cell division but which can also damage the cell's genome when present in excess. Women with CCNE1 amplified tumors are unlikely to respond to PARP inhibitors and thus represent an important unmet need. While there are a number of drugs currently in development in other solid cancers that may be effective in CCNE1 amplified HGSOC, there are currently no animal models to study the function of cyclin E1 in HGSOC or the efficacy of candidate inhibitors. This application describes our aim to develop a mouse model that mimics the human disease, thereby providing a preclinical platform for testing novel cyclinE1 inhibitors. We will construct transgenic mice where the Ccne1 gene can be precisely activated when and where we want it. Using well-established technology, we will engineer mice to express the cyclinE1 protein at high levels in FT secretory epithelial cells, the progenitors of HGSOC. We are very experienced in the generation of such animals and their analysis. Importantly, TP53 is always defective in human HGSC and its loss appears to be a requirement for cells to tolerate the presence of excess cyclinE1. Therefore, our model will incorporate expression of a mutant Tp53. Our laboratory studies suggest these two genetic alterations – Ccne1 over expression and Tp53 mutation – will be enough to generate tumors. It is also possible, however, that additional mutations will be needed for the mice to develop HGSC that mimic the human disease. In the second part of the grant we use data from a genetic screen in FT cells and information from thousands of cancer genomes to find genes that may cooperate with CCNE1 and that could be added to the mice. The study is likely to provide a high return on the invested effort, as the mice will provide an enduring resource - once the model is established it can be used in many settings, providing a powerful ongoing platform for development of CCNE1 inhibitors.