Bone Metastasis Factor-1 in Prostate Cancer/Bone Interaction

描述（由申请人提供）：前列腺癌（PCa）一旦发生骨转移总是致命的。 前列腺癌骨转移的一个特征是显著的成骨细胞表型。 了解导致骨中前列腺癌成骨进展的机制将使我们能够预防，预测和治疗骨转移。 为了实现这一目标，我们已经开发了一种策略，通过蛋白质纯化和蛋白质组学方法的组合来鉴定前列腺癌“转移蛋白质组”，即参与前列腺癌骨转移的蛋白质因子。 为了确保研究结果具有临床相关性，我们使用了疾病相关样本，即，在我们的研究中，骨髓上清液来自前列腺癌患者，有或没有骨转移。 我们从前列腺癌骨转移患者的骨髓上清液中分离出一种新的骨转移因子MDA-BF-1。 有证据表明MDA-BF-1是一种旁分泌因子，由转移性前列腺癌细胞分泌，并在前列腺癌骨转移中介导成骨细胞增殖。 首先，Western blot显示MDA-BF-1仅存在于有骨转移的前列腺癌患者的骨髓上清液中，而不存在于无骨转移的前列腺癌患者中。 其次，免疫组织化学分析显示MDA-BF-1在正常前列腺上皮细胞中不表达，仅由转移性前列腺癌细胞产生。 第三，具有成骨细胞特征的骨源性细胞系（MDA PCa 2b）产生大量的MDA-BF-1，而具有溶骨性特征的骨源性细胞系（PC-3）不产生。 第四，重组MDA-BF-1在体外诱导成骨细胞而非前列腺癌细胞增殖。 第五，初步研究表明，当将溶骨性PCa细胞系PC-3注射到骨中时，MDA-BF-1在这些细胞系PC-3中的表达在体内产生成骨细胞反应。 相比之下，当皮下注射细胞时，MDA-BF-1不影响PC-3细胞的体内生长。 这些观察结果提供了强有力的证据，MDA-BF-1具有成骨细胞刺激活性，可能是骨中前列腺癌成骨细胞进展的主要参与者。 因此，我们假设MDA-BF-1是一种前列腺癌细胞-成骨细胞相互作用因子，介导骨中前列腺癌的成骨进展。 为了验证这一假设，我们建议：目标1。阐明MDA-BF-1对骨PCa动物模型中体内成骨细胞/PCa细胞相互作用的影响;目的2.探讨MDA-BF-1介导成骨细胞增殖和分化的机制;目的3.纯化、鉴定和克隆MDA-BF-1受体（BF 1受体）。

DESCRIPTION (provided by applicant): Prostate cancer (PCa) is invariably fatal once bone metastasis occurs. A characteristic of prostate cancer bone metastasis is the striking osteoblastic phenotype. Understanding the mechanisms that lead to the osteoblastic progression of prostate cancer in bone will enable us to prevent, predict, and treat bone metastasis. Towards this goal, we have developed a strategy to identify the prostate cancer "Metastasis Proteome," protein factors that are involved in prostate cancer bone metastasis, by a combination of protein purification and Proteomics approaches. To ensure that the findings are clinically relevant, we have used disease-relevant samples, i.e., bone marrow supernatant from prostate cancer patients with or without bone metastasis, in our study. We have isolated a novel bone metastasis factor, MDA-BF-1, from the bone marrow supernatants of prostate cancer patients with bone metastasis. Several lines of evidence suggest that MDA-BF-1 is a paracrine factor that is secreted by the metastatic prostate cancer cells and mediates osteoblast proliferation in prostate cancer bone metastasis. First, Western blot showed that MDA-BF-1 is only present in the bone marrow supernatant of prostate cancer patients with bone metastasis but not in those without bone metastasis. Second, immunohistochemical analysis showed that MDA-BF-1 is not expressed in normal prostate epithelial cells and is only produced by the metastatic prostate cancer cells. Third, a bone-derived cell line with osteoblastic features (MDA PCa 2b) produces a high amount of MDA-BF-1, while a bone-derived cell line with osteolytic features (PC-3) does not. Fourth, recombinant MDA-BF-1 induced osteoblast but not prostate cancer cell proliferation in vitro. Fifth, preliminary studies showed that expression of MDA-BF-1 in the osteolytic PCa cell line PC-3 generated an osteoblastic response in vivo when these cells were injected into bone. In contrast, MDA-BF-1 does not affect PC-3 cell growth in vivo when the cells were injected subcutaneously. These observations provide strong evidence that MDA-BF-1 has osteoblast stimulating activity and may be a major player in the osteoblastic progression of prostate cancer in bone. We thus hypothesize that MDA-BF-1 is a prostate cancer cell-osteoblast interacting factor that mediates osteoblastic progression of prostate cancer in bone. To test this hypothesis, we propose to: Aim 1. Elucidate the effects of MDA-BF-1 on osteoblast/PCa cell interactions in vivo in an osseous PCa animal model; Aim 2. Investigate the mechanism of MDA-BF-1-mediated osteoblast proliferation and differentiation; and Aim 3. Purify, identify, and clone the receptor for MDA-BF-1 (BF1-receptor).