Cathepsin D/K诱导骨巨细胞瘤中破骨细胞分化促进溶骨的机制研究

Giant cell tumor of bone (GCTB) is a common primary invasive neoplasm in musculoskeletal system, which shows an osteolytic phenomenon in radiographic imaging and is easy to recurrence after surgery. Nowadays, the lack of animal models of GCTB remains a big problem, which seriously hinders researchers to explore the mechanisms underlying the tumorigenesis of GCTB. In previous works, we successfully isolated the stromal cells of GCTB from patients and established a nude mouse model of GCTB in situ. We found that GCTB stromal cells are capable of promoting the differentiation and maturation of osteoclast in bone in vitro and in vivo. In order to explore the mechanism underlying this promotion made by stromal cells, we then performed a proteomics analysis on the secretome of GCTB stromal cells. The results suggested that Cathepsin D/K (CTSD/K) were highly up-regulated in their secretion levels in the supernatant of GCTB stromal cells compared to those in osteosarcoma cells, which in turn enhance the differentiation of osteoclast. Hence, we hypothesize that stromal cell derived CTSD/K promotes the differentiation of osteoclast, which trigger the tumorigenesis of GCTB. In this study, we want to identify the biological functions of CTSD/K in the cross-talk between GCTB stromal cells and osteoclasts as well as their target cells and substrates using TRAP staining, co-IP, ELISA and etc. We also want to uncover the signaling cascades of CTSD/K in the progress and recurrence of GCTB. We hope our studies on CTSD/K promoting the differentiation of osteoclast and enhance the development of GCTB will provide us novel therapeutic targets and new prognostic indicators of GCTB.

骨巨细胞瘤（GCTB）是一种常见的原发性侵袭性骨肿瘤，影像学表现为溶骨病变，手术后复发仍以溶骨为主。目前GCTB相关研究较少，研究模型缺乏，其病理机制不明。我们前期已建立人GCTB来源的原代基质细胞株，成功构建裸鼠原位成瘤模型，体内外实验发现基质细胞能诱导破骨细胞成熟并导致溶骨；通过蛋白组学分析，发现Cathespin D和K（CTSD/K）在GCTB基质细胞中分泌比骨肉瘤细胞显著上调，且能诱导破骨细胞分化。因此，我们认为GCTB中基质细胞可能通过分泌CTSD/K诱导破骨细胞成熟并促进疾病进展。本课题拟通过体外、体内以及临床病例研究，采用TRAP染色、co-IP、ELISA等方法，分析CTSD/K在GCTB基质细胞诱导破骨细胞分化中的功能及促进溶骨的分子机制，明确其作用靶细胞及靶蛋白，探讨CTSD/K及其下游分子与GCTB溶骨及复发的关联性，为GCTB临床治疗提供新的靶点及预后预测指标。

骨巨细胞瘤（GCTB）是一种常见的原发性侵袭性骨肿瘤，亚洲人发病率远高于欧美国家，影像学表现为溶骨病变，临床治疗术后溶骨性病变复发率较高。目前GCTB相关研究非常少，研究模型缺乏，其病理机制很不清晰。我们前期建立10例人GCTB来源的原代基质细胞系，成功构建了小鼠原位成瘤模型，发现基质细胞体内体外均能诱导破骨细胞分化成熟；同时通过分泌蛋白组学质谱分析，发现Cathespin D和K（CTSD，CTSK）在GCTB基质细胞中显著上调，且能诱导破骨细胞分化并促进溶骨。因此，我们认为GCTB中基质细胞可能通过分泌CTSD/K诱导破骨细胞成熟并促进疾病进程。本课题拟通过体外、动物模型以及临床病例研究，采用TRAP染色、免疫共沉淀、ELISA等实验方法，分析CTSD/K在GCTB基质细胞诱导破骨细胞分化中的功能及促进溶骨的功能及分子机制，明确其作用的靶细胞及靶蛋白，探讨CTSD/K及其下游分子与临床GCTB溶骨及复发的关联性，以及成为预后预测指标及治疗靶点的可能性，为GCTB临床治疗提供新的思路。