Interactions of the WNT and RANKL/OPG pathways in osteomimicry of prostate cancer

在骨转移的过程中，前列腺癌细胞是如何获得成骨细胞样表型(拟成骨)并调节成骨的尚不清楚。我们将验证WNT蛋白，特别是WNT5A，是否促进肿瘤的发展和肿瘤细胞的成骨，并通过核因子受体激活剂B配体(RANKL)和骨保护素(OPG)调节破骨细胞生物学。基于对RANKL/OPG的研究，以及我们最近发现WNT蛋白和RANKL在晚期前列腺癌中高表达，我们将解决三个具体目标。(I)确定趋骨性前列腺癌细胞系和组织在骨转移过程中的WNT和RANKL/OPG谱。(2)分析WNT与RANKL/OPG的相互作用以及骨肿瘤对话中涉及的信号转导途径。我们将使用共培养模型，并通过使用击倒和过度表达技术来评估AIM I中的特定因素。(Iii)为了研究WNT通路在骨转移中的作用，我们将采用动物模型。具有明确WNT特征的成骨和溶骨肿瘤细胞系将被荧光标记并注射到COL1IFP1-α转基因小鼠中。骨骼肿瘤的进展和成骨功能的改变将使用分子成像进行活体监测，并通过组织学和基因表达分析进行分析。这些研究可能找出骨转移的关键信号，为诊断和治疗提供靶向。

In the process of skeletal metastasis it remains unclear how prostate cancer cells acquire an osteoblast-like phenotype (osteomimicry) and modulate osteogenesis. We will test the hypothesis whether WNT proteins, in particular WNT5A, promote tumor development and tumor cell osteomimicry and modulate osteoclast biology through receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). Based on studies on RANKL/OPG and our recent findings that WNT proteins and RANKL are highly expressed in advanced prostate cancer, we will address three specific aims. (I) Define the WNT and RANKL/OPG profile of osteotropic prostate cancer cell lines and tissues during skeletal metastasis. (II) Analyze interactions between WNT and RANKL/OPG and the involved signaling pathways in the bone-tumor dialogue. We will employ co-culture models and assess specific factors from aim I by using knock-down and over-expression techniques. (III) To investigate the role of the WNT pathway in skeletal metastases, we will employ animal models. Osteoblastic and osteolytic tumor cell lines with defined WNT profiles will be fluorescent-labeled and injected into Col1α1-IFP-transgenic mice. Skeletal tumor progression and altered osteoblastic function will be monitored in vivo using molecular imaging and analyzed by histology and gene expression analysis. These studies may identify key signals of skeletal metastasis which could be targeted for diagnosis and therapy.