Project 2

已在多种癌症中鉴定了10号染色体上缺失的磷酸酶和张力蛋白同源物（PTEN）的体细胞突变和缺失，并且在前列腺癌中，PTEN改变发生在至少30%的原发性癌症和63%的转移性癌症中。因为降低的PTEN活性增强了促进肿瘤发生的P1 -3激酶依赖性途径。确定在P1 -3激酶信号传导下游起作用的通路对于理解转化机制和鉴定新的治疗靶点是必不可少的。在转基因小鼠中活化的AKT的表达不足以表型复制前列腺中的PTEN损失，因此需要P1 -3激酶信号传导的额外效应物用于前列腺癌进展超过前列腺上皮内瘤形成（PIN）。我们假设蛋白激酶C相关激酶1（PRK 1;在基因名称后称为PKN 1）是P1 -3激酶效应子，其性质表明其与AKT合作转化前列腺癌细胞。PKN 1是PDK 1的直接底物，在人前列腺癌中过表达，并促进异种移植模型中的增殖，它通过充当组蛋白H3激酶来调节雄激素受体（AR）活性。我们表明，组成型活性PKN 1在小鼠前列腺中的条件性表达足以在22周时产生小鼠PIN。在目标1中，我们使用转基因小鼠来表征PKN 1单独表达和与AKT组合表达所导致的前列腺癌表型。我们将确定PKN 1在转导PTEN缺失引起的致瘤效应中的作用。在目标2中，我们使用异种移植和细胞培养的方法，以确定PKN 1如何刺激肿瘤生长，探索其作为一个分裂沟激酶的功能，并作为一个因素，调节细胞周期调节因子的表达和活性。在目标3中，我们测试PKN 1激酶活性如何促进基因表达的模型。包括PKN 1磷酸化AR和PKN 1产生特异性表观遗传标记。这些目标的成功完成将为PTEN/PI-3激酶信号转导机制提供新的见解，包括PKN 1如何促进前列腺细胞增殖和PKN 1如何调节AR。我们将产生新的前列腺癌临床前模型，重现PTEN缺失时发生的分子事件

Somatic mutations and deletions in phosphatase and tensin homologue deleted on chromosome 10 (PTEN) have been identified in a variety of cancers, and in prostate cancer PTEN alterations occur in at least 30% of primary cancers and 63% of metastatic cancers. Since reduced PTEN activity enhances Pl-3 kinase-dependent pathways that promote tumorigenesis. defining the pathways that operate downstream of Pl-3 kinase signaling is essential for understanding transformation mechanisms and for identifying new therapeutic targets. Expression of activated AKT in transgenic mice is not sufficient to phenocopy PTEN loss in prostate, thus additional effectors of Pl-3 kinase signaling are required for prostate cancer to progress beyond prostate intra-epithelial neoplasia (PIN). We hypothesize that the Protein Kinase C-related kinase 1 (PRK1; termed PKN1 after the gene name) is a Pl-3 kinase effector whose properties suggest it cooperates with AKT to transform prostate cancer cells. PKN1 is a direct substrate of PDK1, is over-expressed in human prostate cancer and promotes proliferation in xenograft models, and it modulates androgen receptor (AR) activity by acting as a histone H3 kinase. We show that conditional expression of constitutively active PKN1 in mouse prostate is sufficient to generate murine PIN at 22 weeks. In Aim 1 we use transgenic mice to characterize prostate cancer phenotypes resulting from PKN1 expression, alone and in combination with AKT. We will determine the role PKN1 plays in transducing tumorigenic effects caused by loss of PTEN. In Aim 2 we use xenograft and cell culture approaches to determine how PKN1 stimulates tumor growth by exploring its function as a cleavage furrow kinase, and as a factor that modulates the expression and activity of cell cycle regulators. In Aim 3 we test models for how PKN1 kinase activity promotes gene expression. Including PKN1 phosphorylation of AR and PKN1 generation of specific epigenetic marks. Successful completion of these aims will provide new insights into PTEN/PI-3 kinase signal transduction mechanisms including how PKN1 promotes prostate cell proliferation and how PKN1 regulates AR. We will generate new pre-clinical models of prostate cancer that recapitulate molecular events that occur with loss of PTEN