Project 1: Molecular Mechanisms Initiating Prostate Cancer Metastasis

项目摘要-项目1 癌症转移是一个非常低效的过程。过去的调查支持的概念，形成的 作为转移性沉积物的孤立肿瘤通常需要数月至数年， 在转移部位普遍存在。使用基因标记的人类PC细胞作为模型，我们发现， 少量转移起始细胞（MIC）可以募集和重编程基因标记的非转移性细胞， PC细胞（称为“旁观者”或“休眠”细胞）参与骨和软组织的癌变 转移MIC具有表达RANKL+、RANK+、c-MET+、p-c-MET+（活化形式 c-MET）和转移性。被MIC募集的旁观者细胞最初是RANKL-，RANK+ c-MET-， p-c-MET-，并且是非转移性的，但是在被MIC募集后，在转移部位形成孤立性肿瘤， 获得MIC表型并成为转移性的，即使在没有MIC的情况下注射小鼠时也是如此 （附录1和2）。我们发现具有MIC和旁观者细胞表型的细胞在血液中 从PC患者新鲜收获的循环（CTC或循环肿瘤细胞）。有趣的是，我们还 显示MIC也可以重编程从PC患者分离的CTC和播散性肿瘤细胞（DTC）。在 支持模型研究，RANKL，p-c-MET和NPR-1，VEGF共受体和下游靶点 RANK介导的信号，在原代人PC组织中得到证实，并显示可预测总生存期。 PC患者在这项研究中，我们将检验具有MIC表型的细胞可以招募和 重新编程旁观者CTC/DTC以参与PC转移级联。我们提出三个具体目标， 测试这个和相关的假设： 具体目标1：检验循环CTC和DTC作为MIC储存库的概念 募集、启动和重编程，并有助于癌症骨和软组织转移。 我们将检验MIC“胁迫”CTC/DTC以放大RANK介导的信号网络的假设 通过前馈机制。具有扩增的RANK网络的细胞可能能够定殖于骨。 具体目标2：确定MIC和旁观者细胞的分子特征， 成功募集、启动和重编程以参与癌症骨转移。我们将 检验新鲜分离和离体扩增的CTC/DTC在被扩增之前必须表达RANK的假设。 由MIC募集、启动和重编程以表达活化的RANK介导的信号网络。 具体目标3：在肿瘤界面发现有希望的治疗靶点- 微环境，并测试靶向相关转录的小分子抑制剂和抗体 信号通路中的转录因子（TF）及其效应物。我们将检验TF是 在PC细胞中协同活化以发展转移表型。针对这些TF（或其 下游效应物）可以高度有效地抑制转移性PC细胞的重编程。

Project Summary - Project 1 Cancer metastasis is a highly inefficient process. Past investigation supports the concept that formation of solitary tumors as metastatic deposits often takes months to years despite the fact that dormant cells are prevalent at the metastatic sites. Using genetically tagged human PC cells as models, we discovered that a small number of Metastasis-Initiating Cells (MICs) can recruit and reprogram genetically tagged non-metastatic PC cells (referred to as "bystander" or "dormant" cells) to participate in cancer bone and soft tissue metastases. MICs have the phenotype of expressing RANKL+, RANK+, c-MET+, p-c-MET+ (an activated form of c-MET) and are metastatic. Bystander cells being recruited by MICs are initially RANKL-, RANK+ c-MET-, p-c-MET-, and are non-metastatic, but after recruitment by MICs, formed solitary tumors at metastatic sites, acquired MICs phenotypes and became metastatic, even when injected in mice in the absence of MICs (Appendices 1 and 2). We found that cells with MIC and bystander cell phenotypes are in the blood circulation (CTCs or circulating tumor cells) freshly harvested from PC patients. Intriguingly, we have also shown that MICs can also reprogram CTCs and disseminated tumor cells (DTCs) isolated from PC patients. In support of the model studies, RANKL, p-c-MET, and NPR-1, a VEGF co-receptor and a downstream target of RANK-mediated signals, was confirmed in primary human PC tissues, and shown to predict the overall survival of PC patients. In this study, we will test the hypothesis that cells with MIC phenotype can recruit and reprogram bystander CTCs/DTCs to participate in PC metastatic cascade. We propose three Specific Aims to test this and related hypotheses: Specific Aim 1: To test the concept that circulating CTCs and DTCs serve as depots for MIC recruitment, initiation and reprogramming and contribute to cancer bone and soft tissue metastases. We will test the hypothesis that MICs "coerce" CTCs/DTCs to amplify a RANK-mediated signaling network through a feed-forward mechanism. Cells with an amplified RANK network may be able to colonize the bone. Specific Aim 2: To determine the molecular features of MICs and bystander cells required for successful recruitment, initiation and reprogramming to participate in cancer bone metastasis. We will test the hypothesis that freshly isolated and ex vivo expanded CTCs/DTCs must express RANK prior to be recruited, initiated and reprogrammed by MICs to express an activated RANK-mediated signal network. Specific Aim 3: To discover promising therapeutic targets at the interface of the tumor- microenvironment, and to test small molecule inhibitors and antibodies targeting relevant transcription factors (TFs) and their effectors in the signal pathways. We will test the hypothesis that TFs are coordinately activated in PC cells to develop the metastatic phenotype. Targeting these TFs (or their downstream effectors) could be highly effective in inhibiting the reprogramming of metastatic PC cells.