Evaluation of PI3K pathway and p110 in prostate cancer

近年来，前列腺肿瘤抑制基因PTEN已被证明是PI3激酶通路的关键调控因子。PTEN蛋白是一种磷酸酶，除了其对蛋白质底物的活性外，还可以使PI3激酶家族的脂质产物去磷酸化。PTEN去除3'-磷酸，这是在PI3激酶家族成员的产物中唯一发现的。PTEN的遗传分析表明，这种PI3磷酸酶活性对其肿瘤抑制功能至关重要。由于这些脂质是调节细胞生长和存活的中枢信号通路的中枢介质，因此假设PTEN功能的丧失应该会增加细胞的生长和存活。所有这些令人兴奋的发现都表明，有必要研究人类前列腺肿瘤中的PI3激酶信号，并建立模型系统，以便研究动物前列腺肿瘤中的PI3激酶途径。在这项资助中，我们将创建单克隆抗血清来研究实际肿瘤样本中关键PI3激酶途径成员的激活状态。此外，我们将建立小鼠模型来测试PI3激酶的p110催化亚基在小鼠前列腺癌模型中的作用。此外，我们将建立小鼠模型，通过产生转基因小鼠来测试p110激酶的作用是否足以形成前列腺肿瘤，在转基因小鼠中，p110的激活突变等位基因通过仅在前列腺组织中活跃的前泡表达。我们还将测试PTEN介导的小鼠肿瘤形成是否需要Pi3激酶活性。为此，我们将生成p110基因的锁定版本，这将使我们能够敲除前列腺中的Pi3激酶功能，该功能已被设计为以PTEN依赖的方式发展前列腺肿瘤。

Recently PTEN, a tumor suppressor gene commonly mutant in prostate, has been demonstrated to be a key regulator of the PI3 kinase pathway. The PTEN protein is a phosphatase which, in addition its activity against protein substrates, can dephosphorylate the lipid products of the PI3 kinase family. PTEN removes the 3'-phosphate, which is the found uniquely in the products of PI3 kinase family members. Genetic analyses of PTEN suggest that this PI3 phosphatase activity is ess3ential to its tumor suppressor function. Since these lipids are, among other things, central mediators of central signaling pathways which mediate both cell growth and survival, it is hypothesized that loss of PTEN function should increase both growth and survival. All this excitement has pointed out the need to study PI3 kinase signaling in human prostate tumors and to generate model systems to allow study of the PI3 kinase pathway in prostate tumors in animals. In this grant we will create monoclonal antisera to study the activation state of key PI3 kinase pathway members in actual tumor samples. In addition we will generate mouse models which test the role of the p110 catalytic subunit of PI3 kinase in mouse prostate cancer models. In addition we will generate mouse models which test the role of the p110 kinase is sufficient for prostate tumor formation by generating a transgenic mouse in which an activated mutant allele of p110 is expressed via the probasin which is only active in prostate tissue. We will also test if Pi3 kinase activity is necessary for PTEN mediated tumor formation in mice, To do this we will generate a loxed version of the p110 gene which will allow us to knock out Pi3 kinase function in the prostates which have been engineered to develop prostate tumors in a PTEN dependent fashion.