Mechanisms regulating prostate epithelium maintenance and regeneration

描述(由申请人提供)：干细胞的鉴定和调节正常前列腺上皮发育和维持的分化程序对于鉴定细胞类型和前列腺癌发生和扩散所涉及的分子变化至关重要(S)。P63基因选择性地表达于各种上皮细胞的基底细胞，是上皮细胞发育所必需的。最近研究表明，P63对于胸腺上皮和表皮干细胞的增殖能力是必不可少的。我们小组和其他人之前的工作表明，在正常的前列腺发育过程中，分泌细胞来自p63阳性的基底细胞，从而代表祖细胞/干细胞。然而，出生后在体内维持前列腺上皮的机制仍有待阐明。提示前列腺基细胞和分泌性细胞在发育过程中是有等级关系的，这增加了成人前列腺的更新依赖于p63阳性的基础干细胞的可能性。虽然来自体内和体外研究的数据都支持这种可能性，但一个截然不同的模型提出，成人分泌细胞能够维持自身的更新，而不需要基础干细胞的显著贡献。本申请中提出的实验旨在阐明成年前列腺上皮在生理条件下和细胞损伤后的更新过程。我们将首先使用一种新的基于DNA类似物的谱系追踪方法来测试成年前列腺上皮是否包含特殊的干/祖细胞，这些细胞在体内反复分裂，产生有丝分裂后细胞(目标1)。在一个平行和互补的努力中，我们将进行遗传谱系追踪，以确定前列腺上皮的体内发育和更新是否依赖于p63阳性的祖细胞/干细胞(目标2)。最后，我们将通过检验p63在调节前列腺干细胞功能中起中心作用的假设(目标3)，开始研究前列腺干细胞调节的分子机制。我们的建议将为正常前列腺上皮在体内发育和更新的方式提供极其宝贵的知识。这些知识对于未来确定前列腺癌发生发展所涉及的细胞类型(S)和分子异常是绝对必要的。 与公共卫生相关：前列腺体由两种主要类型的细胞组成，即基细胞和分泌细胞。有人提出，基底细胞产生分泌细胞，从而代表干细胞。然而，前列腺上皮的维持方式尚不清楚。在这项建议中，我们计划确定成年后前列腺上皮的再生是否依赖于基底干细胞的增殖。此外，我们还将研究干细胞功能的调节机制。这些研究将为正常前列腺细胞的形成和分化提供非常重要的知识。这一知识将有助于阐明前列腺癌的起源细胞，因此，将大大促进前列腺癌领域的发展。

DESCRIPTION (provided by applicant): The identification of stem cells and differentiation programs regulating the development and maintenance of the normal prostate epithelium is essential for the identification of the cell type(s) and molecular changes involved in the development and propagation of prostate cancer. The p63 gene is selectively expressed in basal cells of various epithelia and is required for epithelial development. p63 has been recently shown to be essential for the proliferative potential of stem cells both in the thymus epithelium and the epidermis. Previous work from our group and others suggests that during normal prostate development, secretory cells derive from p63-positive basal cells, which thus represent progenitor/stem cells. However, the mechanisms underlying the in vivo maintenance of the prostate epithelium during post-natal life remain to be clarified. The suggestion that basal and secretory prostate cells are hierarchically related during development raises the possibility that the renewal of the adult prostate depends on p63-positive basal stem cells. While data from both in vivo and in vitro studies provide support for such a possibility, a contrasting model proposes that adult secretory cells are capable of sustaining their own renewal, without significant contribution from basal stem cells. The experiments proposed in this application are aimed at clarifying the renewal process of the adult prostate epithelium both in physiologic conditions and after cell injury. We will first employ a novel DNA-analog-based lineage tracing method to test whether the adult prostate epithelium contains specialized stem/progenitor cells that repeatedly divide in vivo to give rise to post-mitotic cells (Aim 1). In a parallel and complementary effort, we will perform genetic lineage tracing to determine whether the in vivo development and renewal of the prostate epithelium depends on p63-positive progenitor/stem cells (Aim 2). Finally, we will begin to study the molecular mechanisms of prostate stem cell regulation by testing the hypothesis that p63 plays a central role in modulating prostate stem cell functions (Aim 3). Our proposal will provide extremely valuable knowledge on the way the normal prostate epithelium develops and is renewed in vivo. Such knowledge is absolutely required for the future identification of the cell type(s) and molecular abnormalities involved in prostate cancer development and progression. PUBLIC HEALTH RELEVANCE: The prostate glands are composed of two main types of cells, i.e. basal and secretory cells. It has been proposed that the basal cells give rise to secretory cells and thus represent the stem cells. However, the way the prostate epithelium is maintained is unknown. In this proposal, we plan to establish whether the regeneration of the prostate epithelium in adult life depends on the proliferation of basal stem cells. In addition, we will study the mechanisms regulating stem cell functions. These studies will provide very important knowledge on how normal prostate cells form and differentiate. This knowledge will shed light on the cell of origin of prostate cancer and, therefore, will substantially contribute to the advancement of the prostate cancer field.