骨髓微环境FGF10/FGFR2信号通路调控线粒体代谢在AML干细胞自我更新中的作用及机制研究

Leukemia stem cell (LSC) is the important reason for refractory and relapse of acute myeloid leukemia (AML), thus it is of great significance to explore the biological characteristics and eradicating strategy of LSC. Accumulating evidence showed that mitochondrial metabolism was essential for the maintenance of LSC self-renewal. The bone marrow stromal cells (BMSCs) promote AML chemo-resistance through enhancing mitochondrial functions. However, the roles and mechanisms of BMSCs-regulating mitochondrial metabolism in LSC self-renewal of AML remain unclear. In our previous study, we found that BMSCs treated with chemotherapy mediated AML chemo-resistance through paracrine of FGF10 and activation of FGFR2. The expression of FGFR2 in AML LSC was significantly increased and inhibition of FGFR2 decreased the expression of mitochondrial metabolic regulator PIN4, PGC1α and mitochondrial complex in AML LSC, suggesting that bone marrow microenvironment plays an important role in LSC self-renewal through regulation of mitochondrial metabolism by FGF10/FGFR2 signaling pathway. In the following study, we intend to investigate the effects of FGF10/FGFR2 signaling pathway from bone marrow microenvironment on AML LSC self-renewal, and clarify the regulatory mechanisms of FGF10/FGFR2 in mitochondrial metabolism of AML LSC. Then we investigate the possibility of eradicating LSC by targeting FGF10/FGFR2 and its regulation of mitochondrial metabolism. Our study will be of great importance for revealing the mechanisms of AML LSC self-renewal and chemo-resistance, and provides a novel strategy for overcoming drug resistance and eradicating minimal residual disease in AML.

急性髓系白血病（AML）难治复发的根源是白血病干细胞（LSC）的存在，探寻其生物学特性及清除策略具有重要意义。研究发现，线粒体代谢对维持LSC自我更新至关重要，骨髓基质细胞（BMSCs）通过增强线粒体代谢促进白血病耐药，但其在AML LSC中的作用尚不明确。我们发现，化疗后BMSCs通过旁分泌FGF10并激活FGFR2介导AML耐药，且FGFR2在AML LSC中高表达，抑制FGFR2显著下调LSC中PIN4、PGC1α及线粒体复合物的表达，提示骨髓微环境可能通过FGF10/FGFR2通路增强线粒体代谢促进AML LSC自我更新及耐药。本项目拟在前期工作基础上，研究骨髓微环境FGF10/FGFR2通路异常活化对AML LSC自我更新的影响，明确FGF10/FGFR2通路对AML LSC线粒体代谢的调控作用，阐明骨髓微环境调控线粒体代谢庇护LSC的分子机制，预期为克服AML耐药提供新策略。

骨髓微环境为白血病干细胞（LSCs）提供庇护所作用，是AML难治、复发的根本原因。研究显示，线粒体氧化代谢功能改变与LSCs自我更新及白血病的发生发展密切相关，骨髓基质细胞（BMSCs）通过增强线粒体代谢促进白血病耐药。我们前期发现，化疗后BMSCs通过旁分泌FGF10并激活FGFR2介导AML耐药，提示骨髓微环境FGF10/FGFR2通路在AML中发挥重要作用。本项目拟以骨髓微环境为切入点，探讨化疗后BMSCs通过FGF10/FGFR2信号调控线粒体代谢在AML LSCs自我更新中的作用机制。我们研究发现，FGF10、FGFR2、PIN4、PGC-1α、SDHB、UQCRC1和ATP5A1在AML患者骨髓微环境及AML LSCs中高表达。体外研究证实化疗后BMSCs降低AML LSCs化疗药物敏感性、促进集落形成、抑制LSCs凋亡，并增强LSCs线粒体数量、膜电位、活性氧（ROS）及OXPHOS水平。进一步研究发现，外源性重组人FGF10介导AML LSCs化疗药物抵抗、显著升高FGFR2、PIN4、PGC-1α、SDHB、UQCRC1和ATP5A1的表达及增加线粒体数量、膜电位、活性氧（ROS）及OXPHOS水平；应用慢病毒下调AML LSCs FGFR2表达或应用FGFR2抑制剂阻断FGFR2信号可抑制其线粒体代谢，并通过抑制下游MAPK/AKT信号通路逆转AML LSCs耐药。此外我们还发现，下调PGC1α表达可抑制AML LSCs线粒体代谢，增强AML LSCs对化疗药物的敏感性。本项目阐明了骨髓微环境FGF10/FGFR2信号调控AML干细胞线粒体代谢在AML耐药中的重要作用，对于寻求新的靶向治疗、改善AML患者预后具有重要的临床意义。