Regulation of Tumor Cell Dormancy in Human Prostate Cancer Bone Metastasis

人前列腺癌骨转移中肿瘤细胞休眠的调控

• 批准号: 401023770
• 负责人: Professor Dr. Tobias Lange, Ph.D.
• 金额: --
• 依托单位: Institut für Anatomie I
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/401023770?language=en
• 关键词: Regulation; Tumor; Cell; Dormancy; Human

The general aim of this project is to improve our understanding of the mechanisms that regulate outgrowth or otherwise dormancy of PCa bone metastases. This is a major clinical problem as it accounts for late metastatic relapse after unpredictable periods of minimal residual disease. Our preliminary data, which are mainly based on our newly established spontaneous bone metastasis xenograft models of human PCa, and the literature collectively suggest that the outgrowth of PCa bone metastases might be suppressed by a paracrine and/or autocrine interplay of the soluble factors Sparc and Dkk1 that apparently inhibits tumor colonization by promoting the EMT-phenotype of metastatic cells (EMT=epithelial-to-mesenchymal transition). The first aim of this project will therefore be to obtain for the first time direct functional evidence whether the bone marrow (BM) colonization changes upon genetic modification (e.g., inducible knockdown) of Sparc or Dkk1 in our spontaneous metastasis PCa xenograft models (WP1). Our preliminary work demonstrates that our models closely recapitulate the process of EMT, that they have clinical and functional relevance, and that we are able to monitor the switch from dormancy to colonization in vivo. In WP2 we will determine whether Dkk1 exerts its effects on tumor cell dormancy not only by directly targeting the tumor cells, but also the BM stromal cells. For this purpose, we will use immunodeficient mice with mutated Dkk1-binding site of the main receptor Lrp5 (Lrp5-G170V) or with knockout of the co-receptors Krm1 and/or Krm2 for cell line-based PCa xenograft experiments. In addition, we will engraft these mice with our newly established patient-derived xenograft (PDX) model 'C5' that spontaneously metastasizes to the bone and expresses Dkk1 and Sparc. WP1 and WP2 are embedded into a long-standing, close collaboration between the applicant and the Institute of Osteology and Biomechanics at UKE (Prof. Thorsten Schinke). Prof. Schinke will contribute his expertise in static, dynamic and cellular histomorphometry and provide the Lrp5-G170V and Krm1/2 k.o. mice for WP2. WP1 and WP2 might demonstrate that elevated levels of Sparc and Dkk1 and Dkk1 receptor activation suppress the switch from dormancy to colonization. The expected results would provide a rationale for future experiments on how to maintain Sparc and Dkk1 expression in the phase of minimal residual cancer to prevent metastatic relapse (presumably in a second funding period). Moreover, in order to identify novel markers of metastatic outgrowth in PCa by an unbiased approach, we will use a recently established method of bioluminescence imaging-guided in situ laser ablation of xenograft primary tumors and corresponding bone metastases and subsequent proteome analysis (WP3, cooperation with Prof. H. Schlüter, UKE). The resulting candidates will be functionally validated in a second funding period.

本项目的总体目标是提高我们对调节前列腺癌骨转移瘤生长或休眠机制的理解。这是一个主要的临床问题，因为它导致了不可预测的微小残留疾病期后的晚期转移复发。我们的初步数据，这主要是基于我们新建立的自发性骨转移异种移植模型的人前列腺癌，和文献共同表明，前列腺癌骨转移的生长可能被抑制的旁分泌和/或自分泌的相互作用的可溶性因子Sparc和Dkk 1，显然抑制肿瘤定植促进EMT表型的转移细胞（EMT=上皮细胞间质转化）。因此，该项目的第一个目的将是首次获得直接的功能证据，即骨髓（BM）定植是否在遗传修饰后发生变化（例如，在我们的自发转移性PCa异种移植模型（WP 1）中，Sparc或Dkk 1的诱导性敲低）。我们的初步工作表明，我们的模型密切概括EMT的过程中，他们有临床和功能的相关性，我们能够监测开关从休眠到定植在体内。在WP 2中，我们将确定Dkk 1是否不仅通过直接靶向肿瘤细胞，而且还通过靶向BM基质细胞来对肿瘤细胞休眠发挥作用。为此，我们将使用具有主要受体Lrp 5（Lrp 5-G170 V）的突变的Dkk 1结合位点或具有共受体Krm 1和/或Krm 2敲除的免疫缺陷小鼠进行基于细胞系的PCa异种移植实验。此外，我们将用我们新建立的患者来源的异种移植物（PDX）模型“C5”移植这些小鼠，该模型自发转移到骨并表达Dkk 1和Sparc。WP 1和WP 2嵌入到申请人与UKE（Thorsten Schinke教授）的骨骼学和生物力学研究所之间的长期密切合作中。Schinke教授将贡献他在静态，动态和细胞组织形态学方面的专业知识，并提供Lrp 5-G170 V和Krm 1/2 k.o. WP 2的小鼠。WP 1和WP 2可能表明Sparc和Dkk 1水平升高以及Dkk 1受体激活抑制了从休眠到定殖的转换。预期的结果将为未来关于如何在最小残留癌症阶段保持Sparc和Dkk 1表达以防止转移性复发的实验提供理论基础（可能在第二个资助期）。此外，为了通过无偏倚的方法鉴定PCa中转移性生长的新标志物，我们将使用最近建立的生物发光成像引导原位激光消融异种移植原发性肿瘤和相应的骨转移以及随后的蛋白质组分析的方法（WP 3，与H. Schlüter，UKE）。由此产生的候选人将在第二个供资期间接受职能验证。