Notch Signaling and Prostate Cancer Bone Metastases

描述（由申请人提供）：前列腺癌（PC）骨转移的特点是能够诱导成骨细胞病变和局部骨形成。这种骨骼反应的病理生理学目前尚不清楚。最近的许多报道表明，成骨转移性PC细胞是仿骨细胞，能够表达已知由成骨细胞表达的基因和蛋白质。Notch信号通路在决定细胞命运中起着关键作用。已经证明成骨细胞分化依赖于Notch1被DIl1 （Notch配体）激活，我们之前已经证明Notch1负责PC细胞系的拟骨特性。因此，我们假设前列腺癌骨转移表达功能性Notch受体，该受体在骨环境中被激活，导致前列腺癌细胞转化为成骨细胞样细胞。为了验证这一假设，我们将使用来自成骨细胞、溶骨细胞和混合转移细胞、人间充质干细胞和人前列腺骨转移样本的人类PC细胞系。本研究的目的是：(1)表征Notch受体和Notch配体在转移性前列腺癌中的表达。将在PC细胞系和人类临床样本中检测RNA和蛋白质的表达。(2)明确转移性前列腺癌成骨转化的分子机制。Western blot和凝胶转移分析以及交互激活研究将用于阐明其机制。(3)确定Notch信号在前列腺癌骨转移中的作用。Notch活性会被药理学抑制。PC细胞的命运将在体外和小鼠模型中进行检验。这些研究的发现将首次为解释前列腺癌骨骼转移诱导成骨细胞病变的能力提供新的机制。因此，将为开发新的药物设计靶点和治疗干预提供基础，以对抗PC转移到骨骼的衰弱状况。

DESCRIPTION (provided by applicant): Prostate cancer (PC) bone metastases are characterized by their ability to induce osteoblastic lesions and local bone formation. The pathophysiology of this skeletal response is not currently known. Many reports have recently shown that osteoblastic metastatic PC cells are osteomimetic and capable of expressing genes and proteins which are known to be expressed by osteoblasts. The Notch signaling pathway plays a pivotal role in determining cell fate. It has been shown that osteoblast differentiation is dependent upon Notch1 activation by DIl1 (Notch ligand) and we have previously demonstrated that Notch1 is responsible for the osteomimetic properties of PC cell lines. Therefore, we hypothesize that prostate carcinoma bone metastases express functional Notch receptors, which are activated in the bone environment resulting in a transformation of prostate carcinoma cells into osteoblast like cells. To test this hypothesis, we will use human PC cell lines which are derived from osteoblastic, osteolytic and mixed metastases, human mesenchymal stem cells, and samples from human prostate bone metastases. The aims of this study are: (1) Characterize the expression of Notch receptors and Notch ligands in metastatic prostate carcinoma. RNA and protein expression will be examined in PC cell lines and human clinical samples. (2) Characterize the molecular mechanisms responsible for osteoblastic transformation of metastatic prostate carcinoma. Western blot and gel shift analysis and transactivation studies will be utilized to elucidate the mechanism. (3) Determine the role of Notch signaling in prostate cancer bone metastasis. Notch activity will be inhibited pharmacologically. The fate of PC cells will be examined in vitro and in a mouse model. Findings from these studies will provide the first documentation of a novel mechanism to explain the ability of prostate cancer's skeletal metastases to induce osteoblastic lesions. A basis will thereby be provided for the development of a new target for drug design and therapeutic intervention to combat the debilitating condition of PC metastases to bone.