Griessinger Emmanuel, Vargaftig Jacques, Horswell Stuart, Taussig David C, Gribben John, Bonnet Dominique
INSERM U1065, C3M, Team 4 Inflammation, Cancer, Cancer Stem Cells, Nice, France; Haematopoietic Stem Cell Laboratory, The Francis Crick Institute, London, United Kingdom.
Haematopoietic Stem Cell Laboratory, The Francis Crick Institute, London, United Kingdom; Division of Hematology, René Huguenin Hospital-Curie Institute, Saint-Cloud, France.
Exp Hematol. 2018 Mar;59:66-71.e4. doi: 10.1016/j.exphem.2017.12.002. Epub 2017 Dec 15.
Xenograft assay allows functional analysis of leukemia-initiating cells of acute myeloid leukemia primary samples. However, 40% of samples derived from patients with better outcomes fail to engraft in immunodeficient mouse recipients when conventional protocols are followed. At diagnosis, the engraftment of intermediate-risk group samples cannot be anticipated. In this study, we decided to further explore the reasons for xenograft success and failure. No differences in extracellular phenotype, apoptosis, or cell cycle profile could distinguish samples that engraft (engrafter [E]) from samples that do not engraft (nonengrafter [NE]) in NSG mice. In addition, ex vivo long-term culture assay revealed, after 5 weeks, a lower content of leukemic-LTC-initiating cells in the NE samples associated with a lower expansion rate capacity. One-week co-cultures with mesenchymal or osteoblastic or endothelial cells did not influence the proliferation rate, suggesting that E and NE samples are genuinely rapidly or slowly expanding independent of external cue. Engraftment success for some NE samples was consistently observed in recipient mice analyzed 6 months later than the conventional 3-month period. Eventually we implemented a flow cytometry-based assay, which allowed us to predict, in 1 week, the fast or delayed engraftment potential of a noncharacterized acute myeloid leukemia sample. This approach will be especially useful in selecting intermediate-risk-group patient samples and restricting the experimental duration to a 3-month period and, eventually, in reducing the number of animals and the cost and effort of unnecessary xenograft failures.
异种移植试验可对急性髓系白血病原代样本中的白血病起始细胞进行功能分析。然而，按照传统方案操作时，40%来自预后较好患者的样本无法在免疫缺陷小鼠受体中植入。在诊断时，无法预测中危组样本的植入情况。在本研究中，我们决定进一步探究异种移植成功与失败的原因。在NSG小鼠中，细胞外表型、凋亡或细胞周期谱方面的差异无法区分能植入的样本（植入者[E]）和不能植入的样本（未植入者[NE]）。此外，体外长期培养试验显示，5周后，NE样本中白血病长期培养起始细胞的含量较低，其扩增率也较低。与间充质细胞、成骨细胞或内皮细胞共培养1周并不影响增殖率，这表明E样本和NE样本的真正快速或缓慢扩增与外部信号无关。在比传统的3个月时间晚6个月分析的受体小鼠中，持续观察到一些NE样本的植入成功。最终，我们实施了一种基于流式细胞术的检测方法，该方法使我们能够在1周内预测未表征的急性髓系白血病样本的快速或延迟植入潜力。这种方法在选择中危组患者样本、将实验持续时间限制在3个月以及最终减少动物数量以及不必要的异种移植失败的成本和工作量方面将特别有用。
