The Role of Adipocyte-Induced Inflammation in Prostate Tumor Progression

描述（由申请人提供）：骨是前列腺癌（PCa）转移的主要部位，大多数晚期PCa患者会出现无法治愈的骨病变并发症。尽管在PCa研究中取得了重要进展，但PCa骨转移背后的分子机制尚未得到很好的理解。新出现的文献证据表明，已知会扰乱骨微环境稳态并导致骨破坏的肥胖和炎症等疾病可能是前列腺肿瘤在骨中定植和生长的促成因素。半胱氨酸蛋白酶，组织蛋白酶K（CTSK），是一种主要的胶原酶参与骨细胞骨吸收。在前列腺癌中，与来自相同患者的相应原发性肿瘤和软组织相比，骨转移中的CTSK水平更高。此外，CTSK在炎症中起重要作用，是一个新的肥胖症合并标志物。我们以前的研究表明，CTSK缺陷小鼠骨髓中的脂肪细胞成熟严重受损。骨中前列腺肿瘤的进展在不存在CTSK的情况下延迟，并且与影响肿瘤侵袭性和破骨细胞分化的两种促炎因子水平的显著降低相关（即，CXCL1和CXCL2），进一步强调了这种蛋白酶在骨中炎症相关肿瘤侵袭性中的作用。因此，我们假设骨中转移性前列腺癌的生长和侵袭性是由表达CTSK的骨髓脂肪细胞和涉及CXCL 1和CXCL 2趋化因子的脂肪细胞驱动的炎症驱动的。该项目由三个具体目标组成。目的1是研究骨髓源性脂肪细胞对巨噬细胞炎症的贡献以及随之而来的前列腺肿瘤细胞侵袭性和侵袭性的增加。目的2是确定脂肪细胞和巨噬细胞来源的CXCL1和CXCL2如何影响体外肿瘤细胞增殖，侵袭，细胞外基质降解和细胞因子谱，以及肿瘤细胞侵袭性的变化如何最终驱动骨肿瘤微环境中的巨噬细胞表型。目的3是评估高脂肪饮食对骨髓炎症的直接影响，并确定所产生的促炎状态对骨中肿瘤进展的后果。这些研究将利用体内和体外方法的组合，包括：肿瘤细胞-脂肪细胞-巨噬细胞共培养系统、骨转移的体内敲除模型、免疫印迹、ELISA测定、细胞因子阵列、RT PCR和慢病毒敲除技术。将研究肿瘤细胞增殖、侵袭性、细胞外基质降解、细胞因子谱和巨噬细胞表型对CXCL 1和CXCL 2以及潜在的其他脂肪细胞和巨噬细胞衍生因子的反应。这些研究将验证CTSK驱动的事件在骨髓炎症中的重要性，并研究CXCL1和CXCL2作为新的信号传导因子和骨转移性疾病治疗干预的潜在靶点。)

DESCRIPTION (provided by applicant): Bone is a primary site of metastasis from prostate cancer (PCa) and most patients with advanced PCa experience complications from the bone lesions that are incurable. Despite important advances that have been made in PCa research, molecular mechanisms behind PCa bone metastases are not well understood. Emerging literature evidence suggests that conditions like obesity and inflammation, known to disturb homeostasis in the bone microenvironment, and contribute to bone destruction, may be contributing factors to colonization and growth of prostate tumors in the bone. The cysteine protease, cathepsin K (CTSK), is a major collagenase involved in osteoclastic bone resorption. In prostate cancer, CTSK levels are higher in bone metastases compared to corresponding primary tumors and soft tissues from the same patients. In addition, CTSK plays important roles in inflammation and is a newly merging marker of adiposity. Our previous studies have shown that adipocyte maturation is severely impaired in bone marrow of CTSK deficient mice. Progression of prostate tumors in the bones in delayed in the absence of CTSK and correlates with significant reduction in levels of two pro-inflammatory factors that affect tumor aggressiveness and osteoclast differentiation (i.e., CXCL1 and CXCL2), further underlining the role of this protease in inflammation-related tumor aggressiveness in the bone. Therefore, we hypothesize that growth and aggressiveness of metastatic prostate cancer in the bone is driven by the CTSK-expressing bone marrow adipocytes and the adipocyte- driven inflammation involving CXCL1 and CXCL2 chemokines. The project is composed of three specific aims. The Aim 1 is to investigate contributions of bone marrow-derived adipocytes to macrophage inflammation and the consequent increase in prostate tumor cell invasiveness and aggressiveness. The Aim 2 is to determine how adipocyte and macrophage-derived CXCL1 and CXCL2 affect tumor cell proliferation, invasion, extracellular matrix degradation and cytokine profiles in vitro, and how the changes in tumor cell aggressiveness ultimately drive macrophage phenotype in the bone tumor microenvironment. The Aim 3 is to assess direct effects of high fat diet on inflammation of the bone marrow and determine the consequences of the resulting pro-inflammatory state on tumor progression in the bone. These studies will utilize combination of in vivo and in vitro approaches including: tumor cell-adipocyte-macrophage co-culture system, in vivo knockout model of bone metastasis, immunoblotting, ELISA assays, cytokine arrays, RT PCR and Lentivirus knockdown technology. Changes in tumor cell proliferation, invasiveness, extracellular matrix degradation, cytokine profiles, and macrophage phenotype will be studied in response to CXCL1 and CXCL2 as well as potentially other adipocyte and macrophage-derived factors. These studies will validate the importance of CTSK-driven events in bone marrow inflammation and investigate CXCL1 and CXCL2 as novel signaling factors and potential targets for therapeutic intervention in bone metastatic disease. )