MOUSE MODELS OF OVARIAN CANCER

我们提出了一些策略来产生可遗传的卵巢癌小鼠模型。这些模型将有助于了解疾病的病因，并提供更现实的系统来评估诊断、预防和治疗方法。考虑到卵巢癌是美国妇女实体瘤死亡的第四大原因，以及目前存在的三种更常见的致命实体瘤的转基因模型，创建转基因卵巢癌模型是一个特别合理的目标。考虑到卵巢癌与乳腺癌等疾病相比的死亡风险，进一步强调了建立这种模型的必要性。在美国，卵巢癌的发病率约为每10万名妇女中有3.3人。这种疾病每年产生大约20,000个新病例，但它们导致的死亡频率非常高，即每年有近15,000名美国妇女死于这种疾病。相比之下，乳腺癌的发病率约为每年180 000例，每年死亡人数约为46 000人。因此，乳腺癌的发病率是卵巢癌的9倍，但死亡率是卵巢癌的3倍。在这个应用中，我们证明了有足够的资源来开始开发卵巢癌的遗传模型，并描述了获得创建第二代模型所需的资源和信息的方法。为了实现这些目标，我们提出以下具体目标：具体目标1：确定过度表达、异常表达或失活时可能导致卵巢癌风险增加的基因：有足够的信息可以开始生产具有几种主要作用基因/致癌基因的转基因动物。一个更大的问题是关于隐性作用基因的选择，即那些失去功能的基因有助于卵巢癌的发生。鉴定这些基因用于转基因动物的操作是本目标的重点。特定目标2：创造患卵巢癌风险增加的基因工程小鼠。我们已经在大鼠基因组中发现了一种逆转录病毒样元素，这种元素在大鼠卵巢中特异性表达。我们已经克隆了它负责卵巢特异性表达的部分，并证明它驱动报告基因的表达。这个启动子将作为我们最初努力开发卵巢癌小鼠模型的支柱。在这个目的中，我们建议使用这个启动子来构建表达卵巢癌中重要的正常和突变基因的转基因小鼠。对于隐性基因，即肿瘤/生长抑制基因，我们有能力产生种系“敲除”，但更令人感兴趣的是使用该启动子来驱动卵巢特异性体内生产的可能性，作为一种以卵巢特异性方式功能性“敲除”肿瘤/生长抑制基因的手段。特异性目标3：确定在MOSE细胞中特异性表达的启动子。该启动子目前可用于多种卵巢细胞类型，包括表面上皮细胞。因此，当基因在该启动子的控制下被操纵时产生的卵巢肿瘤可能来源于多种细胞类型。尽管膜和颗粒细胞肿瘤在女性中并不像来自表面上皮的肿瘤那样常见，但这种肿瘤模型将具有一定的意义。在这里，我们提出鉴定一个小鼠卵巢表面上皮细胞特异性启动子。特异性目标4：增加癌的频率和特异性，减少潜伏期。在这里，我们将根据需要检查各种遗传和生理策略，以增加小鼠卵巢癌的频率，特异性和减少潜伏期。

We propose strategies to produce inheritable mouse models of ovarian cancer. Such models will aid in understanding the disease's etiology and provide more realistic systems in which to evaluate diagnostic, prevention, and treatment methods. Creation of transgenic ovarian cancer models is a particularly rational goal considering this disease is the fourth leading cause of deaths from solid tumors in American women and transgenic models of the three more commonly lethal solid tumors currently exist. The need for such models is further underscored when one considers the risk of death from ovarian cancer compared to for example breast cancer. The incidence of ovarian cancer is approximately 3.3 per 100,000 women in the United Sates. This yields approximately 20,000 new cases annually but they result in a remarkably high frequency of death, i.e. nearly 15,000 American women die from the disease each year. In contrast, breast cancer has a frequency of approximately 180,000 cases per year and accounts for approximately 46,000 annual deaths. Thus, breast cancer has a frequency 9 times as high as ovarian cancer but results in 3-times as many deaths. In this application, we demonstrate that sufficient resources exist to begin to develop inheritable models of ovarian cancer and describe approaches to obtain the resources and information needed to create second generation models. To accomplish these goals, we propose the following Specific Aims: SPECIFIC AIM number 1: Identify the genes which when overexpressed, expressed in aberrant form, or inactivated will likely lead to an increased risk of ovarian cancer: Sufficient information is available to start producing transgenic animals with several dominantly acting genes/oncogenes. A much larger problem exists with regard to selection of recessively acting genes, i.e. those genes whose lost function contributes to ovarian oncogenesis. Identification of such genes for manipulation in transgenic animals is the focus of this Aim. SPECIFIC AIM number 2: Creation of genetically engineered mice at increased risk of developing ovarian cancer. We have identified a retrovirus-like element in the rat genome which is specifically expressed in rat ovaries. We have cloned the portion of it responsible for ovarian specific expression and demonstrated that it drives reporter gene expression. This promoter will serve as the backbone of our initial efforts to develop mouse models of ovarian cancer. In this Aim, we propose to use this promoter to create transgenic mice constitutively expressing normal and mutated genes of importance in ovarian cancer. In the case of recessive genes, i.e. tumor/growth suppresser genes, we have the capability to produce germline "knockouts", but of greater interest is the possibility of using this promoter to drive ovarian specific intrabody production as a means to functionally "knockout" tumor/growth suppresser genes in an ovarian specific manner. SPECIFIC AIM number 3: Identify a promoter that is specifically expressed in MOSE cells. The promoter currently available functions in multiple ovarian cell types including the surface epithelium. Therefore, the ovarian tumors produced when genes are manipulated under control of this promoter may derive from multiple cell types. Such tumor models will be of certain interest although theca and granulosa cell tumors are not as common in women as those derived from the surface epithelium. Here, we propose to identify a mouse ovarian surface epithelial cell specific promoter. SPECIFIC AIM number 4: Increase carcinoma frequency and specificity and decrease latency. Here, we will examine various genetic and physiological strategies as needed to increase frequency, specificity, and decrease latency of ovarian cancer in mice.