Notch Signaling and Prostate Cancer Bone Metastases

描述(申请人提供)：前列腺癌(PC)骨转移的特征是它们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。近年来的研究表明，成骨转移性PC细胞是一种仿骨细胞，能够表达已知的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。已经证明成骨细胞的分化依赖于Notch1(Notch配体)的激活，我们先前已经证明Notch1与PC细胞系的拟骨特性有关。因此，我们假设前列腺癌骨转移瘤表达功能性Notch受体，该受体在骨环境中被激活，导致前列腺癌细胞向成骨细胞样细胞转化。为了验证这一假设，我们将使用来自成骨细胞、溶骨性和混合性转移瘤的人PC细胞系、人间充质干细胞和来自人前列腺骨转移瘤的样本。本研究的目的是：(1)研究Notch受体及其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)探讨转移性前列腺癌成骨细胞转化的分子机制。将利用蛋白质印迹和凝胶位移分析以及反式激活研究来阐明其机制。(3)探讨Notch信号在前列腺癌骨转移中的作用。缺口活性将被药物抑制。PC细胞的命运将在体外和小鼠模型中进行检测。这些研究的发现将首次提供一种新的机制来解释前列腺癌的骨转移诱导成骨细胞损伤的能力。从而为药物设计和治疗干预提供了新的靶点，以对抗PC转移到骨的衰弱状况。

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.