Proteases in Prostate Cancer Bone Metastasis

描述(由申请人提供)： 在前列腺癌中，蛋白水解酶调节细胞的增殖和死亡、肿瘤的侵袭、转移和血管生成。蛋白分解对正常和肿瘤诱导的骨重建也是必不可少的。虽然已经在一些癌症患者身上测试了蛋白酶抑制剂，但还没有人进入专门针对骨转移患者的临床试验。我们必须应用广泛而全面的策略来选择适当的针对骨转移的蛋白酶靶点，并且我们必须提高我们对肿瘤细胞与骨之间关于骨微环境中的蛋白酶活性的相互作用的理解。我们还必须开发监测蛋白酶抑制的系统，将其作为临床试验的一个关键终点。因此，我们的具体目标是：(1)分析前列腺癌细胞-骨相互作用对与前列腺癌骨转移相关的蛋白分解的影响；(2)确认在AIM 1的器官型模型系统中鉴定的蛋白在前列腺癌细胞在体内的骨骼定植过程中表达并具有活性；(3)验证上述蛋白水解酶类别和单个蛋白水解酶是否参与了由前列腺癌细胞-骨相互作用诱导的蛋白分解；以及(4)使用蛋白酶激活的探针来检测被证实与前列腺癌骨转移有关的蛋白水解酶的活性以及蛋白酶抑制剂对这些活性的抑制。为了实现这些目标，将使用新的骨器官模型、骨转移模型和临床人类骨转移组织。基因图谱方法将被用来监测肿瘤和骨髓基质细胞中蛋白酶基因表达的变化。将监测前列腺癌引起的骨骼或相关底物的蛋白分解，并将使用各种方法来测量和可视化个别蛋白酶的活性。特定的基质来源的蛋白水解酶在骨转移模型中的作用将通过使用普通和特定的蛋白水解酶抑制剂以及特定蛋白水解酶基因缺失的细胞、骨骼和小鼠来检验。如果可以非侵入性地监测蛋白水解酶活性，那么使用蛋白水解酶抑制剂的临床试验将提供更多的信息，我们将在前列腺癌骨转移的体外和体内模型中验证蛋白水解酶激活的成像探针选择性成像蛋白水解酶活性的能力以及它被蛋白酶抑制剂消除的能力。

DESCRIPTION (provided by applicant): In prostate cancer, proteases are well known to regulate cell proliferation and death, tumor invasion, metastasis, and angiogenesis. Proteolysis is also essential for normal and tumor-induced bone remodeling. Although protease inhibitors have been tested in some patients with cancer, none have entered into clinical trials specifically for patients with bone metastasis. We must apply a broad and comprehensive strategy to choose the appropriate protease targets specific for bone metastasis, and we must improve our understanding of the interplay between tumor cells and bone with regard to protease activity in the bone microenvironment. We must also develop systems for monitoring the inhibition of proteases as a key endpoint in clinical trials. Therefore, our Specific Aims are to: (1) Analyze the effects of prostate tumor cell-bone interactions on the proteolysis associated with prostate cancer bone metastases; (2) confirm that the proteases identified in the organotypic model system of Aim 1 are expressed and active during the colonization of bone by prostate cancer cells in vivo; (3) validate that the protease classes and individual proteases identified above contribute to the proteolysis induced by prostate tumor cell-bone interactions; and (4) use protease-activated probes to image both activities of proteases validated as contributing to prostate cancer bone metastasis as well as the abrogation of those activities by protease inhibitors. To accomplish these goals will use novel bone organotypic models, bone metastasis models, and clinical human bone metastasis tissues. Gene profiling methods will be used to monitor changes in protease gene expression in tumor and bone marrow stromal cells. Prostate cancer-induced proteolysis of bone or relevant substrates will be monitored, and a variety of methods will be used to measure and visualize activity of individual proteases. The roles of specific stromal-derived proteases in bone metastasis models will be examined using general and specific protease inhibitors and as well as cells, bones, and mice rendered genetically null for specific proteases. As clinical trials with protease inhibitors will be more informative if protease activity can be monitored non-invasively, we will validate protease-activated imaging probes for their ability to selectively image protease activity and its abrogation by protease inhibitors in both in vitro and in vivo models of prostate cancer bone metastasis.