BMPs and prostate cancer skeletal metastases

描述(由申请人提供)：前列腺癌(CAP)骨骼的一个有趣的方面 转移瘤主要形成成骨细胞病变。CAP转移的成骨本质可能为其生物学提供线索；然而，CAP骨转移部位的骨生成机制尚不清楚。这种作用的潜在媒介是骨形态发生蛋白(BMP)，它是诱导成骨细胞形成的蛋白质。我们提供了CAP肿瘤转移产生BMPs的数据，并且BMP-7在成骨细胞CAP细胞系中表达失调。我们假设，随着CAP细胞进入更具侵袭性的状态，BMP的表达在转录水平上受到失调，由此导致的BMP的过度表达促进了成骨细胞病变的发展。为了验证我们的假设，我们将执行以下具体目标：目标1：确定BMPs在骨形成机制中的作用程度。为此，我们将成骨细胞帽肿瘤植入SCID-HU小鼠体内的人胎骨中，然后检测(1)抑制BMP(抗体和反义)或(2)在低表达BMP的帽细胞系中过表达BMP对成骨细胞损伤形成的影响。目的：探讨CAP细胞BMP-7表达异常的原因。为此，我们将确定导致BMP-7不同调控的顺式作用位点和反式作用因素。 成骨细胞诱导的C4-2B帽细胞中的启动子与其非成骨细胞诱导的亲代LNCaP细胞的比较。我们还将使用启动子激活的实时成像在体内测试这一点。目的：确定骨形态发生蛋白(BMP)是否依赖于血管内皮生长因子(VEGF)促进转移性骨肿瘤的成骨细胞活性。我们有数据表明，BMPs增加了血管内皮生长因子的表达，而抑制血管内皮生长因子则降低了CAP诱导的前成骨细胞的活性。为此，我们将测试BMPs通过阻断BMP活性来调节血管内皮生长因子的表达和活性(包括血管生成和成骨活性)的能力。我们还将确定阻断血管内皮生长因子对帽介导的成骨细胞活性的影响。该项目完成后，将为设计预防或延缓前列腺癌常见的痛苦后遗症--盖骨转移的策略提供线索。

DESCRIPTION (provided by applicant): An intriguing aspect of prostate cancer (CaP) skeletal metastases is that they form primarily osteoblastic lesions. The osteoblastic nature of CaP metastases may provide clues to their biology; however, the mechanisms of bone production at CaP skeletal metastatic sites are poorly understood. Potential mediators of this effect are bone morphogenetic proteins (BMP), which are proteins that induce osteoblastogenesis. We present data that CaP tumor metastases produce BMPs in situ and that BMP-7 expression is dysregulated in osteoblastic CaP cell lines. We hypothesize that as CaP cells progress to a more aggressive state, BMP expression is dysregulated at the transcriptional level and the resulting overexpression of BMP promotes the development of osteoblastic lesions. To test our hypothesis, we will perform the following specific aims: Aim 1: Determine the extent of BMPs contribution to the mechanism of CaP-induced bone formation. In this aim, we will implant osteoblastic CaP tumors into human fetal bone implanted in SCID mice (SCID-hu) and will then determine the effect of (1) inhibiting BMP (antibodies and antisense) or (2) overexpressing BMP in a low BMP-expressing CaP cell line on osteoblastic lesion formation. Aim 2: Investigate the etiology of dysregulated BMP-7 expression in CaP cells. To perform this, we will identify cis-acting sites and trans-acting factors that account for the differential regulation of the BMP-7 promoter in osteoblast-inducing C4-2B CaP cells compared to its non-osteoblast-inducing parental LNCaP cells. We will also test this in vivo using real-time imaging of the promoter activation. Aim 3: Determine if BMP promotion of osteoblastic activity in CaP metastases depends on vascular endothelial growth factor (VEGF). We have data showing that BMPs increase VEGF expression and that inhibition of VEGF diminishes CaP-induced pro-osteoblast activity. In this aim, we will test the ability of BMPs to regulate VEGF expression and activity (including angiogenesis, as well as pro-osteoblastic activity) by blocking BMP activity. We will also determine the effects of blocking VEGF on CaP-mediated pro-osteoblastic activity. When completed, this project clues that may enable design of strategies to prevent or delay progression of CaP skeletal metastases, which are common and painful sequelae of prostate cancer.