State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
Clin Cancer Res. 2017 Feb 1;23(3):789-803. doi: 10.1158/1078-0432.CCR-16-0226. Epub 2016 Aug 4.
Leukemia stem cells (LSC), which are insensitive to tyrosine kinase inhibitors (TKI), are an important source of TKI resistance and disease relapse in chronic myelogenous leukemia (CML). Obstacles to eradicating LSCs include limited understanding of the regulation network of LSCs. The current study aimed to examine the interplay between NF-κB and FOXM1/β-catenin, and the effect of its chemical intervention on CML LSCs.
The interplay between NF-κB and FOXM1/β-catenin was analyzed by reciprocal coimmunoprecipitation (co-IP) and chromatin immunoprecipitation (ChIP) assay in CML cells. The effect of disturbing NF-κB and FOXM1/β-catenin by niclosamide on the self-renewal capacity and survival of LSCs was evaluated in vitro in human primary CML CD34 cells and in vivo in CML mice.
Reciprocal co-IP experiments showed physical interaction of p65 and FOXM1. p65 promoted transcription of FOXM1 gene. ChIP assay revealed recruitment of p65 on the promoter of FOXM1 gene. Conversely, FOXM1 and β-catenin positively regulated the nuclear translocation and transcriptional activity of NF-κB in CML cells. Niclosamide disrupted the positive feedback loop between NF-κB and FOXM1/β-catenin, thereby impairing the self-renewal capacity and survival of CML LSCs. Niclosamide decreased the long-term engraftment of human CML LSCs in NOD-SCID IL2Rγ chain-deficient (NOG) mice, and prolonged the survival of CML mice.
Interaction of p65 with FOXM1/β-catenin is critical in CML and its disruption by niclosamide eradicates LSCs. These findings may improve the understanding of a self-renewal regulatory mechanism of LSCs and offer a rationale-based approach to eliminate LSCs in CML. Clin Cancer Res; 23(3); 789-803. ©2016 AACR.
白血病干细胞（LSC）对酪氨酸激酶抑制剂（TKI）不敏感，是慢性髓性白血病（CML）中 TKI 耐药和疾病复发的重要来源。根除 LSC 的障碍包括对 LSC 调节网络的认识有限。本研究旨在研究 NF-κB 和 FOXM1/β-catenin 之间的相互作用，以及其化学干预对 CML LSC 的影响。
通过 CML 细胞中的相互共免疫沉淀（co-IP）和染色质免疫沉淀（ChIP）实验分析 NF-κB 和 FOXM1/β-catenin 之间的相互作用。在人原代 CML CD34 细胞中和 CML 小鼠体内，通过尼克罗米德干扰 NF-κB 和 FOXM1/β-catenin 对 LSC 自我更新能力和存活的影响进行体外评估。
相互 co-IP 实验表明 p65 和 FOXM1 之间存在物理相互作用。p65 促进 FOXM1 基因的转录。ChIP 实验显示 p65 募集到 FOXM1 基因的启动子上。相反，FOXM1 和 β-catenin 正向调节 CML 细胞中 NF-κB 的核转位和转录活性。尼克罗米德破坏了 NF-κB 和 FOXM1/β-catenin 之间的正反馈回路，从而损害了 CML LSC 的自我更新能力和存活。尼克罗米德减少了人 CML LSC 在 NOD-SCID IL2Rγ 链缺陷（NOG）小鼠中的长期植入，并延长了 CML 小鼠的存活时间。
p65 与 FOXM1/β-catenin 的相互作用在 CML 中是至关重要的，尼克罗米德的破坏可根除 LSC。这些发现可能提高对 LSC 自我更新调节机制的认识，并为消除 CML 中的 LSC 提供基于理论的方法。临床癌症研究；23(3)；789-803。©2016AACR。
