Mouse Models of ErbB-2 and Cyclin D1 in Prostate Cancer

在目前的研究中，我们的目标是直接确定ErbB-2和细胞周期蛋白D1在前列腺癌细胞增殖和转化中的作用。ErbB-2和cyclin D1在前列腺癌、乳腺癌和结肠癌中经常过度表达。我们的实验室有助于目前的理解，细胞周期蛋白D1基因是转录激活的一些生长因子和致癌基因，包括致癌ErbB-2。我们和其他人已经表明，细胞周期蛋白D1的丰度是通过细胞周期的G1期的进展速度限制，并需要通过Ras和ErbB-2在成纤维细胞检测转化。这些研究的中心假设是ErbB-2对细胞周期蛋白D1的调节在促进前列腺细胞增殖中起关键作用。我们建议直接使用转基因小鼠来验证这一假设。确定ErbB-2和细胞周期蛋白D1在前列腺癌进展中的作用，并确定细胞周期蛋白D1的调节机制及其对前列腺细胞增殖的影响，将为前列腺肿瘤生长的机制提供重要的见解。尽管已经制备了在前列腺中过度表达侵袭性癌基因并导致前列腺癌的转基因小鼠，但本文所述的实验集中于与人前列腺癌有关的两种基因产物（ErbB-2和细胞周期蛋白D-1）。此外，这些转基因小鼠可能在测试拟议的前列腺癌治疗方法中证明是非常有价值的。目标1.探讨ErbB-2在前列腺细胞增殖中的作用。已经制备了含有在Probasin启动子控制下的野生型人ErbB-2受体的转基因小鼠，并将对其进行分析，并将分析在Probasin启动子控制下的人ErbB-2受体的突变形式，其含有在人肿瘤中发现的16个氨基酸的框内外显子缺失。我们的实验室在转基因小鼠的生产方面有相当丰富的经验。本研究旨在探讨ErbB-2过表达在前列腺细胞增殖中的作用以及ErbB-2在促进前列腺细胞转化和肿瘤发生中的作用。目标二。探讨细胞周期蛋白D1在前列腺细胞增殖中的作用。在Probasin启动子的控制下，正在产生过表达平坦标记的细胞周期蛋白D1 cDNA的转基因小鼠。该目的将确定细胞周期蛋白D1过表达在前列腺细胞增殖/或肿瘤形成中的作用以及细胞周期蛋白D1在增强前列腺细胞转化中的作用。由于细胞周期蛋白D1的过表达已被证明能够补充某些癌基因的转化能力，并且是ErbB-2的转化能力所必需的，因此将Probasin- ErbB-2小鼠与Probasin-细胞周期蛋白D1小鼠杂交，并评估肿瘤发作和进展的速率。

In the current studies we aim to directly determine the role of ErbB-2 and cyclin D1 in cellular proliferation and transformation in prostate cancer cells. Both ErbB-2 and cyclin D1 are frequently over-expressed in prostate, breast and colon cancer. Our laboratory has contributed to the current understanding that the cyclin D1 gene is transcriptionally activated by a number of growth factors and oncogenes, including oncogenic ErbB-2. We and others have shown that the abundance of cyclin D1 is rate-limiting in progression through the G1 phase of the cell-cycle and is required for transformation by Ras and ErbB-2 in fibroblast assays. The central hypothesis of these studies is that ErbB-2 regulation of cyclin D1 plays a critical role in promoting prostate cellular proliferation. We propose to test this hypothesis directly using transgenic mice. Determining the role of ErbB-2 and cyclin D1 in prostate cancer progression and determining the mechanisms by which cyclin D1 is regulated and its effects on prostate cell proliferation will provide important insights into the mechanisms governing prostate tumor growth. Thought transgenic mice have been made which over-express aggressive oncogenes in the prostate and lead to Prostate cancer, the experiments described here focus on two gene products (ErbB-2 and cyclin D-1) implicated in human Prostate cancer. Furthermore, these transgenic mice may prove extremely valuable in the testing of proposed Prostate cancer therapeutics. Aim 1. To determine the role of ErbB-2 in prostate cell proliferation in vivo. Transgenic mice containing a wild type human ErbB-2 receptor under the control of the Probasin promoter have been made and will be analyzed and a mutant form of the human ErbB-2 receptor, which contains a 16 amino acid in frame exon deletion found in human tumors, under the control of the Probasin promoter will be analyzed. Our laboratory has considerable experience in the generation of transgenic mice. This Aim will determine role of ErbB-2 over expression in prostate cellular proliferation and the role of ErbB-2 in enhancing prostate cellular transformation and tumorigenesis. Aim 2. To determine the role of cyclin D1 in prostate cell proliferation in vivo. Transgenic mice are being generated over expressing a flat-tagged cyclin D1 cDNA under the control of the Probasin promoter. This Aim will determine the role of cyclin D1 over expression in Prostate cellular proliferation/or tumor formation and the role of cyclin D1 in enhancing prostate cellular transformation. As cyclin D1 over-expression has been shown to compliment the transforming capacity of certain oncogenes and to be necessary for transformation capacity by ErbB-2, the Probasin- ErbB-2 mice will be crossed with the Probasin-cyclin D1 mice and the rate of tumor onset and progression will be assessed.