CXCL10促进多发性骨髓瘤耐药性和骨破坏的机制研究

Multiple component in bone marrow microenvironment can promote drug resistance and bone lesion in multiple myeloma (MM), but the interaction pattern and induced cytokines have not been fully clarified. Chemokine CXCL10 has been reported to be positively correlated with MM malignancy, but the mechanism is unknown. We found that the expression profile of MM cytokines was significantly altered after co-culture with bone marrow mesenchymal stem cells (MSC) by human cytokine array screening and single-cell sequencing, in which CXCL10 was significantly up-regulated. The level of CXCL10 and macrophage ratio in bone marrow of patients with relapsed MM were significantly higher than those of primary MM patients, and CXCL10 promoted the anti-apoptosis ability of MM cells. CXCL10 may be an important factor inducing MM drug resistance and bone destruction. We will explore the molecular mechanism of CXCL10 promoting MM drug resistance as well as macrophage activation and differentiation into osteoclasts by in vitro cell experiments and KaLwRij mouse MM model, and evaluate the efficiency of targeting CXCL10 combined with chemotherapy on MM cells. This project will reveal a new mechanism of bone marrow microenvironment promoting MM malignancy and provide reference for the development of therapeutic strategies targeting CXCL10 and bone marrow microenvironment.

骨髓微环境中的多种成员可以促进多发性骨髓瘤（MM）的耐药性产生和骨破坏，但与MM之间的作用方式和介导的细胞因子尚未完全明确；已报道趋化因子CXCL10与MM恶性程度正相关但是其作用机制未明。我们前期通过骨髓间充质干细胞（MSC）与MM共培养后用单细胞测序和细胞因子芯片筛选发现MM细胞因子表达谱被显著改变，其中CXCL10显著上调；临床复发MM患者骨髓中CXCL10水平和巨噬细胞比率显著高于初发患者，且CXCL10能促进MM细胞抗凋亡的能力。本课题提出CXCL10可能是诱发MM产生耐药性和骨破坏的重要因子，并利用体外细胞实验和KaLwRij小鼠MM模型深入探究CXCL10促进MM耐药性和巨噬细胞活化并向破骨细胞分化的分子机制，评估靶向CXCL10联合化疗对MM细胞的杀伤效果。本项目将揭示骨髓微环境促进MM恶性表型的一种新机制，并为开发靶向CXCL10和骨髓微环境的治疗策略提供参考。

骨髓基质细胞(bone marrow stromal cells, BMSCs)是多发性骨髓瘤(MM)骨髓微环境的重要组成部分，会导致T细胞功能障碍并促进MM进展，但其作用机制尚不完全清楚。本项目旨在探究BMSCs对骨髓微环境的调节作用及机制。我们发现BMSCs促进MM分泌CXCL10，且临床上CXCL10和MM的疾病进展和临床不良预后相关。我们发现在Vk*MYC和5TGM1 MM小鼠模型以及难治性或复发性MM患者的中CXCL10将γδ T细胞招募导骨髓，并且MM中的γδ T细胞出现功能失调，表达PD-1增加并以产生IL-17为主。且IL-17是髓系来源抑制细胞MDSCs的调节因子，与骨破坏相关。TCRδ-/-小鼠的显示显著减轻的骨破坏和更高的生存率，体外过继转移实验表明并且只有向TCRδ-/-小鼠移植野生型小鼠而不是IL-17-/-小鼠扩增的γδ T细胞能促进骨髓瘤进展。进一步的机制研究表明，骨髓缺氧微环境刺激了γδ T细胞中类固醇受体共激活因子3 (SRC-3)的表达，其与转录因子RORγt相互作用并促进IL-17的表达。并且使用SRC-3抑制剂SI-2，干扰SRC-3和RORγt之间的相互作用，在体内体外可抑制γδ T细胞中IL17A的表达，并缓解小鼠模型中MM的进展，同时增强化疗的抗MM疗效。我们的研究结果揭示了骨髓微环境在MM进展过程中诱导γδ T细胞功能障碍中的作用，并建议SRC-3抑制剂作为增强针对γδ T细胞的免疫治疗的候选药物。