Endothelial-to-osteoblast transition in prostate cancer bone metastasis

项目摘要/摘要 骨转移是前列腺癌(Pca)发病率和死亡率的主要影响因素。PCA骨 转移瘤是一种独特的成骨细胞，以新骨形成为特征，可促进肿瘤生长。 骨头。因此，pca细胞与其错误诱导的骨之间的双向相互作用在pca中起着关键作用。 骨骼的进展。已有的假设是，转移性前列腺癌通过刺激新骨形成来诱导新骨形成。 骨髓中成骨细胞的增殖。然而，我们最近证明了肿瘤相关的 内皮细胞可以通过一种鲜为人知的内皮细胞到成骨细胞的过程产生成骨细胞。 成骨细胞(EC-to-OSB)转化，在转化过程中产生具有独特性质的EC-OSB杂交细胞。我们的 研究表明，肿瘤诱导的EC-to-OSB转换是导致成骨细胞的机制之一 前列腺癌的骨转移。EC-OSB杂合细胞在前列腺癌中惊人的成骨作用的新见解 骨转移为在肿瘤微环境中靶向这些细胞提供了新的理论基础。 我们假设，肿瘤诱导的EC-OSB转换产生EC-OSB杂交细胞，这为 支持骨转移性前列腺癌生长的旁分泌因子。我们的目标是将EC-OSB杂交细胞作为目标 改进骨转移的治疗方法。我们将：目标1.确定内皮细胞的潜在机制 细胞向成骨细胞(EC-OSB)的转变。EC-to-OSB转化需要抑制血管生成 以及内皮细胞中成骨细胞生成途径的激活。我们的初步结果表明，BMP4 激活Notch-Hey1途径抑制血管生成，激活p38MAPK-β-catenin-osx途径刺激血管生成 成骨作用。我们将研究BMP4如何整合这两条途径来重新编程内皮细胞。目标 2.鉴定促进PCa进展的EC-OSB杂合细胞分泌因子(EC-OSB因子)。EC-OSB 用iTRAQ(蛋白质)和RNAseq(基因)分析杂交细胞分泌组。Tenascin C是 与CTGF和Verscan一起被识别，这两个词一起可能构成“EC-to-OSB签名”。我们会 研究这些EC-OSB因子在体内外对PCa细胞活性的影响。“EC-OSB签名” 还将使用临床样本作为成骨细胞性骨转移的生物标志物进行测试。目标3.发展 针对EC-OSB杂交细胞的策略，以改善PCa骨转移的治疗结果。选委会- OSB杂交细胞可能与前述的从头治疗耐药有关。我们将研究我们是否 可以通过联合卡波赞替尼或卡巴紫杉醇(靶向PCa)改善PCa骨转移的治疗结果 肿瘤)和Rad-223(靶向EC-OSB杂交细胞)。目标4.确定是否发生从EC到OSB的转换 正常骨和肿瘤诱导骨中EC-OSB杂合细胞的比例。我们产生了一个新的替身 报告小鼠(Col11-gfp/tie2-cre/rosa-td番茄)，其中EC为rfp+，OsB为gfp+，EC-osb为 RFP+/GFP+，以检测EC-OSB杂交细胞是否参与正常的骨发育及其比例 在肿瘤诱导的骨骼中。

Project Abstract/Summary Bone metastases are the major contributing factors to prostate cancer (PCa) morbidity and mortality. PCa bone metastases are uniquely osteoblastic and characterized by new bone formation, which promotes tumor growth in bone. Thus, bi-directional interaction between the PCa cells and their mis-induced bone plays a critical role in PCa progression in bone. It has been assumed that metastatic PCa induces new bone formation by stimulating the proliferation of osteoblasts in the bone marrow. However, we recently demonstrated that tumor-associated endothelial cells could give rise to osteoblasts through a little-appreciated process known as endothelial cell-to- osteoblast (EC-to-OSB) conversion, generating in the process EC-OSB hybrid cells with unique properties. Our studies showed that tumor-induced EC-to-OSB conversion is one mechanism that leads to osteoblastic bone metastasis of PCa. This new insight into the surprising bone-forming role of EC-OSB hybrid cells in PCa bone metastasis provides a novel rationale to target these cells in the tumor microenvironment. We hypothesize that tumor-induced EC-to-OSB conversion generates EC-OSB hybrid cells, which provide paracrine factors to support metastatic PCa growth in bone. Our objective is to target EC-OSB hybrid cells for improving therapy for bone metastasis. We will: Aim 1. Determine the mechanisms underlying endothelial cell-to-osteoblast (EC-to-OSB) transition. EC-to-OSB conversion requires both the inhibition of angiogenesis and activation of osteoblastogenesis pathways in endothelial cells. Our preliminary results indicate that BMP4 activates the Notch-Hey1 pathway to inhibit angiogenesis and the p38MAPK-β-catenin-OSX pathway to stimulate osteogenesis. We will examine how BMP4 integrates these two pathways to reprogram the endothelial cells. Aim 2. Identify EC-OSB hybrid cell secreted factors (EC-OSB factors) that promote PCa progression. EC-OSB hybrid cell secretome was examined by both iTRAQ (protein) and RNAseq (gene) analyses. Tenascin C was identified along with CTGF and versican, which together may constitute an “EC-to-OSB signature”. We will investigate the effects of these EC-OSB factors on PCa cell activity in vitro and in vivo. The “EC-OSB signature” will also be tested as biomarkers for osteoblastic bone metastasis using clinical samples. Aim 3. Develop strategies that target EC-OSB hybrid cells to improve therapy outcomes for PCa bone metastasis. The EC- OSB hybrid cells may contribute to de novo therapy resistance described previously. We will examine whether we can improve therapy outcomes for PCa bone metastasis by combining cabozantinib or cabazitaxel (targets PCa tumor) with Rad-223 (targets EC-OSB hybrid cells). Aim 4. Determine whether EC-to-OSB transition occurs in normal bone and the fraction of EC-OSB hybrid cells in tumor-induced bone. We generated a new Double Reporter Mice (col11-GFP/Tie2-cre/Rosa-tdTomato), in which EC are RFP+, OSB are GFP+, and EC-OSB are RFP+/GFP+, to examine whether EC-OSB hybrid cells are involved in normal bone development and their fraction in tumor-induced bone.