针对Ph+ALL白血病启动细胞治疗优化的实验研究

Relapse, the major cause of treatment failure in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL), seriously affects the long-term survival of Ph+ALL patients. Leukemia propagating cells (LPC), defined by their ability to initiate human leukemia and self-renew in immunocompromised mice, almost equal to leukemia stem cells. Relapse of Ph+ALL may result from the persistence of LPC. Using an anti-CD122-conditioned NOD/SCID xenograft mouse assay, we have recently reported that LPC are enriched in the CD34+CD38-CD58- fraction in human Ph+ALL. Further cohort study demonstrated that Ph+ALL patients with LPC (CD34+CD38-CD58- cells) phenotype at diagnosis exhibited significantly higher cumulative incidence of relapse than the other phenotype group. Our preliminary data showed that an enrichment of the G0 phase of cell cycle, less sensitive to imatinib, the reduced expression of BCR-ABL, and the increased expression of JAK2 and STAT3 in LPC (CD34+CD38-CD58- cells), suggesting the existence of BCR-ABL kinase-independent tyrosine kinase inhibitor (TKI) resistance in Ph+ALL LPC. Moreover, the JAK2-STAT3 pathway promises to be a major determinant of LPC-mediated relapse in Ph+ALL. Based on our previous work, this study attempts to explore the important pathways for providing survival signals to Ph+ALL LPC. Furthermore, the effects of dasatinib alone or in combination with the inhibitors of either JAK, STAT3 or STAT5; interferon-αcombined with TKI, targeting the Ph+ALL LPC and their potential mechanisms will be evaluated in vitro study, in humanized Ph+ALL mouse model and the registered clinical trial. The successful implementation of this pre-clinical study may provide novel therapeutic strategies for the treatment of relapse in Ph+ALL, and it may eventually improve the clinical outcomes of Ph+ALL patients.

复发是Ph+ALL治疗失败的主要原因，白血病启动细胞（LPC）是白血病复发的根源。本课题组前期通过人源化小鼠模型鉴定、临床队列研究证实CD34+CD38-CD58-细胞为Ph+ALL白血病启动细胞，为针对LPC治疗优化的实验研究奠定了基础。预实验发现，①LPC静止期比例增高，对伊马替尼敏感性降低；②BCR-ABL下调，JAK2、STAT3上调，提示LPC可能存在非BCR-ABL依赖的JAK2-STAT3通路激活，并介导耐药和复发。因而，JAK2-STAT3通路有望成为Ph+ALL白血病启动细胞的治疗靶点。本研究旨在通过体外实验、人源化Ph+ALL小鼠模型和注册临床试验，在LPC水平探索与Ph+ALL复发相关的关键信号通路，阐明达沙替尼分别联合JAK2、STAT3或STAT5抑制剂，干扰素-α联合伊马替尼的抗Ph+ALL白血病启动细胞作用及其机制，为优化Ph+ALL复发防治策略奠定基础。

复发是Ph+ALL治疗失败的主要原因，白血病启动细胞是白血病复发的根源。本研究旨在通过体外实验、人源化Ph+ALL小鼠模型和临床队列研究，在白血病启动细胞水平探索与Ph+ALL复发相关的关键信号通路，阐明Nilotinib分别联合JAK2、STAT3或STAT5抑制剂的抗Ph+ALL白血病启动细胞作用及其作用机制，为优化Ph+ALL复发防治策略奠定基础。本项目的如期完成，为从白血病启动细胞角度理解Ph+ALL的复发机制，并为制定有效防治Ph+ALL复发的治疗新策略提供了理论依据。同时，本项目组以骨髓微环境为研究切入点，开展了移植后造血重建不良的发病机制及其干预策略的临床转化研究。.本项目重要研究成果包括：①通过基因测序联合体外实验发现，Ph+ALL白血病启动细胞基因表达谱与其他表型细胞存在显著差异，差异基因主要集中在调节细胞代谢和细胞周期通路的相关基因；②全基因组测序结合体外实验实时定量PCR技术发现，Ph+ALL白血病启动细胞较其他表型细胞异常高表达JAK2；③体外实验及人源化Ph+ALL小鼠体内实验证实，JAK1/JAK2选择性抑制剂Ruxolitinib联合Nilotinib具有良好的抗Ph+ALL白血病启动细胞作用；④前瞻性病例配对临床研究揭示，骨髓微环境异常参与了移植后造血重建不良的发生，将易维适应用于骨髓微环境异常的修复治疗，可改善移植后造血重建；⑤在本项目资助下，项目负责人作为第一作者/通讯作者，在血液学领域排名第一的Blood杂志（2篇）和本领域其他杂志共发表SCI论文12篇；受邀在本领域最高水平国际学术会议大会发言4次、墙报交流8次、获得美国血液学年会“ASH Abstract Achievement Award”5次；获得2项国家发明专利授权；培养博士研究生3名、硕士研究生1名。.总之，本项目从白血病启动细胞和骨髓微环境角度，深入探讨了Ph+ALL复发、移植后造血重建不良的发病机制，对于优化上述疾病的临床防治策略和制定临床新路径提供了理论依据，具有重要的临床转化应用价值。