Peking University People's Hospital, Peking University Institute of Hematology, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, 100044, China.
Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
J Transl Med. 2017 Aug 30;15(1):184. doi: 10.1186/s12967-017-1286-5.
As one of the major treatment obstacles in Philadelphia chromosome-positive acute lymphoblastic leukemia (PhALL), relapse of PhALL may result from the persistence of leukemia-propagating cells (LPCs). Research using a xenograft mouse assay recently determined that LPCs were enriched in the CD34CD38CD58 fraction in human PhALL. Additionally, a cohort study demonstrated that PhALL patients with a LPCs phenotype at diagnosis exhibited a significantly higher cumulative incidence of relapse than those with the other cell phenotypes even with uniform front-line imatinib-based therapy pre- and post-allotransplant, thus highlighting the need for novel LPCs-based therapeutic strategies.
RNA sequencing (RNA-Seq) and real-time quantitative polymerase chain reaction (qRT-PCR) were performed to analyze the gene expression profiles of the sorted LPCs and other cell fractions from patients with de novo PhALL. In order to assess the effects of the selective BCR-ABL and/or Janus kinase (JAK)2 inhibition therapy by the treatment with single agents or a combination of ruxolitinib and imatinib or nilotinib on PhALL LPCs, drug-induced apoptosis of LPCs was investigated in vitro, as well as in vivo using sublethally irradiated and anti-CD122-conditioned NOD/SCID xenograft mouse assay. Moreover, western blot analyses were performed on the bone marrow cells harvested from the different groups of recipient mice.
RNA-Seq and qRT-PCR demonstrated that JAK2 was more highly expressed in the sorted LPCs than in the other cell fractions in de novo PhALL patients. Combination treatment with a selective JAK1/JAK2 inhibitor (ruxolitinib) and nilotinib more effectively eliminated LPCs than either therapy alone or both in vitro and in humanized PhALL mice by reducing phospho-CrKL and phospho-JAK2 activities at the molecular level.
In summary, this pre-clinical study provides a scientific rationale for simultaneously targeting BCR-ABL and JAK2 activities as a promising anti-LPCs therapeutic approach for patients with de novo PhALL.
费城染色体阳性急性淋巴细胞白血病（PhALL）的主要治疗障碍之一是复发，PhALL 的复发可能源于白血病起始细胞（LPCs）的持续存在。最近使用异种移植小鼠检测的研究发现，LPCs 在人 PhALL 中富含 CD34CD38CD58 分群。此外，一项队列研究表明，诊断时具有 LPCs 表型的 PhALL 患者即使在同种异体移植前和移植后均采用一线伊马替尼为基础的治疗，其复发的累积发生率也显著高于其他细胞表型患者，因此强调需要新的基于 LPCs 的治疗策略。
通过对新诊断 PhALL 患者的 LPCs 和其他细胞分群进行 RNA 测序（RNA-Seq）和实时定量聚合酶链反应（qRT-PCR）分析，以分析基因表达谱。为了评估通过单药或鲁索替尼联合伊马替尼或尼罗替尼的联合治疗对 PhALL LPCs 的选择性 BCR-ABL 和/或 JAK2 抑制作用，我们在体外以及通过亚致死剂量照射和抗 CD122 调理的 NOD/SCID 异种移植小鼠检测中研究了药物诱导的 LPCs 凋亡。此外，还对来自不同组受者小鼠的骨髓细胞进行了 Western blot 分析。
RNA-Seq 和 qRT-PCR 表明，与其他细胞分群相比，新诊断 PhALL 患者的 LPCs 中 JAK2 表达更高。体外和人源化 PhALL 小鼠中，联合使用选择性 JAK1/JAK2 抑制剂（鲁索替尼）和尼罗替尼比单独使用任何一种药物或两者联合治疗更有效地消除 LPCs，这是通过降低分子水平的磷酸化-CrKL 和磷酸化-JAK2 活性实现的。
总之，这项临床前研究为同时靶向 BCR-ABL 和 JAK2 活性提供了科学依据，作为一种有前途的针对新诊断 PhALL 患者 LPCs 的治疗方法。
