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

在骨骼转移的过程中，前列腺癌细胞如何获得成骨细胞样表型（拟骨）并调节成骨尚不清楚。我们将检验WNT蛋白，特别是WNT5A是否通过NF-κB配体受体激活剂（RANKL）和骨保护素（OPG）促进肿瘤的发展和肿瘤细胞的骨模拟，并调节破骨细胞生物学。基于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。(1)明确骨转移过程中嗜骨性前列腺癌细胞系和组织的WNT和RANKL/OPG谱。（II）分析WNT与RANKL/OPG之间的相互作用以及骨肿瘤对话中涉及的信号通路。我们将采用共培养模型，并通过敲除和过表达技术评估目标1中的特定因素。（III）为了研究WNT通路在骨骼转移中的作用，我们将采用动物模型。具有明确WNT谱的成骨细胞和溶骨肿瘤细胞系将被荧光标记并注射到col1 α1- ifp转基因小鼠中。骨骼肿瘤的进展和成骨细胞功能的改变将在体内使用分子成像进行监测，并通过组织学和基因表达分析进行分析。这些研究可能会发现骨骼转移的关键信号，为诊断和治疗提供有针对性的依据。

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.