Al-Asadi Mazin Gh, Brindle Grace, Castellanos Marcos, May Sean T, Mills Ken I, Russell Nigel H, Seedhouse Claire H, Pallis Monica
University of Nottingham, School of Medicine, Academic Haematology, Nottingham, UK.
University of Basrah, College of Medicine, Basrah, Iraq.
Oncotarget. 2017 Nov 30;8(67):111405-111418. doi: 10.18632/oncotarget.22808. eCollection 2017 Dec 19.
Dormant leukaemia initiating cells in the bone marrow niche are a crucial therapeutic target for total eradication of acute myeloid leukaemia. To study this cellular subset we created and validated an model employing the cell line TF-1a, treated with Transforming Growth Factor β1 (TGFβ1) and a mammalian target of rapamycin inhibitor. The treated cells showed decreases in total RNA, Ki-67 and CD71, increased aldehyde dehydrogenase activity, forkhead box 03A (FOX03A) nuclear translocation and growth inhibition, with no evidence of apoptosis or differentiation. Using human genome gene expression profiling we identified a signature enriched for genes involved in adhesion, stemness/inhibition of differentiation and tumour suppression as well as canonical cell cycle regulation. The most upregulated gene was the osteopontin-coding gene SPP1. Dormant cells also demonstrated significantly upregulated beta 3 integrin (ITGB3) and CD44, as well as increased adhesion to their ligands vitronectin and hyaluronic acid as well as to bone marrow stromal cells. Immunocytochemistry of bone marrow biopsies of AML patients confirmed the positive expression of osteopontin in blasts near the para-trabecular bone marrow, whereas osteopontin was rarely detected in mononuclear cell isolates. Unsupervised hierarchical clustering of the dormancy gene signature in primary acute myeloid leukaemia samples from the Cancer Genome Atlas identified a cluster enriched for dormancy genes associated with poor overall survival.
骨髓微环境中处于休眠状态的白血病起始细胞是实现急性髓系白血病完全根除的关键治疗靶点。为了研究这一细胞亚群，我们构建并验证了一个模型，该模型采用细胞系TF-1a，用转化生长因子β1（TGFβ1）和雷帕霉素哺乳动物靶标抑制剂进行处理。处理后的细胞总RNA、Ki-67和CD71水平降低，醛脱氢酶活性增加，叉头框03A（FOX03A）核转位和生长受到抑制，且无凋亡或分化迹象。通过人类基因组基因表达谱分析，我们鉴定出一个特征，该特征富含参与黏附、干性/分化抑制、肿瘤抑制以及经典细胞周期调控的基因。上调最明显的基因是骨桥蛋白编码基因SPP1。休眠细胞还表现出β3整合素（ITGB3）和CD44显著上调，以及对其配体玻连蛋白和透明质酸以及对骨髓基质细胞的黏附增加。对急性髓系白血病患者骨髓活检进行免疫细胞化学分析证实，小梁旁骨髓附近的原始细胞中骨桥蛋白呈阳性表达，而在单核细胞分离物中很少检测到骨桥蛋白。对来自癌症基因组图谱的原发性急性髓系白血病样本中休眠基因特征进行无监督层次聚类分析，鉴定出一个富含与总体生存率低相关的休眠基因的簇。
