Proteases in Prostate Cancer Bone Metastasis

描述（由申请人提供）： 在前列腺癌中，众所周知，蛋白酶可调节细胞增殖和死亡、肿瘤侵袭、转移和血管生成。蛋白水解对于正常和肿瘤诱导的骨重塑也至关重要。尽管蛋白酶抑制剂已在一些癌症患者中进行了测试，但尚未进入专门针对骨转移患者的临床试验。我们必须采用广泛而全面的策略来选择针对骨转移的合适的蛋白酶靶点，并且我们必须提高对肿瘤细胞与骨之间在骨微环境中蛋白酶活性方面的相互作用的理解。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关键终点。因此，我们的具体目标是：（1）分析前列腺肿瘤细胞-骨相互作用对前列腺癌骨转移相关蛋白水解的影响； (2)确认Aim 1的器官模型系统中鉴定的蛋白酶在体内前列腺癌细胞定植于骨的过程中表达并具有活性； (3) 验证上述鉴定的蛋白酶类别和单个蛋白酶有助于前列腺肿瘤细胞-骨相互作用诱导的蛋白水解； (4) 使用蛋白酶激活探针对经验证有助于前列腺癌骨转移的蛋白酶活性以及蛋白酶抑制剂消除这些活性进行成像。为了实现这些目标，将使用新型骨器官模型、骨转移模型和临床人类骨转移组织。基因分析方法将用于监测肿瘤和骨髓基质细胞中蛋白酶基因表达的变化。将监测前列腺癌诱导的骨或相关底物的蛋白水解，并且将使用多种方法来测量和可视化单个蛋白酶的活性。将使用通用和特异性蛋白酶抑制剂以及在基因上对特定蛋白酶无效的细胞、骨骼和小鼠来检查特定基质衍生的蛋白酶在骨转移模型中的作用。如果可以非侵入性地监测蛋白酶活性，则使用蛋白酶抑制剂的临床试验将提供更多信息，因此我们将验证蛋白酶激活成像探针在前列腺癌骨转移的体外和体内模型中选择性成像蛋白酶活性及其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.