Ehx Grégory, Fransolet Gilles, de Leval Laurence, D'Hondt Stéphanie, Lucas Sophie, Hannon Muriel, Delens Loïc, Dubois Sophie, Drion Pierre, Beguin Yves, Humblet-Baron Stéphanie, Baron Frédéric
Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA)-I3, University of Liège, Liège, Belgium.
Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Oncoimmunology. 2017 Apr 12;6(5):e1314425. doi: 10.1080/2162402X.2017.1314425. eCollection 2017.
The demethylating agent 5-azacytidine (AZA) has proven its efficacy in the treatment of myelodysplastic syndrome and acute myeloid leukemia. In addition, AZA can demethylate intron 1 () leading to the generation of regulatory T cells (Treg). Here, we investigated the impact of AZA on xenogeneic graft-vs.-host disease (xGVHD) and graft-vs.-leukemia effects in a humanized murine model of transplantation (human PBMCs-infused NSG mice), and described the impact of the drug on human T cells . We observed that AZA improved both survival and xGVHD scores. Further, AZA significantly decreased human T-cell proliferation as well as IFNγ and TNF-α serum levels, and reduced the expression of GRANZYME B and PERFORIN 1 by cytotoxic T cells. In addition, AZA significantly increased Treg frequency through hypomethylation of as well as increased Treg proliferation. The latter was subsequent to higher STAT5 signaling in Treg from AZA-treated mice, which resulted from higher IL-2 secretion by conventional T cells from AZA-treated mice itself secondary to demethylation of the IL-2 gene promoter by AZA. Importantly, Tregs harvested from AZA-treated mice were suppressive and stable over time since they persisted at high frequency in secondary transplant experiments. Finally, graft-vs.-leukemia effects (assessed by growth inhibition of THP-1 cells, transfected to express the luciferase gene) were not abrogated by AZA. In summary, our data demonstrate that AZA prevents xGVHD without abrogating graft-vs.-leukemia effects. These findings could serve as basis for further studies of GVHD prevention by AZA in acute myeloid leukemia patients offered an allogeneic transplantation.
去甲基化药物5-氮杂胞苷（AZA）已在骨髓增生异常综合征和急性髓系白血病的治疗中证明了其疗效。此外，AZA可使内含子1去甲基化，从而导致调节性T细胞（Treg）的产生。在此，我们在人源化小鼠移植模型（输注人外周血单核细胞的NSG小鼠）中研究了AZA对异种移植物抗宿主病（xGVHD）和移植物抗白血病效应的影响，并描述了该药物对人T细胞的影响。我们观察到，AZA改善了存活率和xGVHD评分。此外，AZA显著降低了人T细胞增殖以及IFNγ和TNF-α血清水平，并降低了细胞毒性T细胞中颗粒酶B和穿孔素1的表达。此外，AZA通过使去甲基化显著增加了Treg频率，并增加了Treg增殖。后者是由于来自AZA处理小鼠的Treg中STAT5信号更高，这是由于AZA处理小鼠本身的常规T细胞分泌的IL-2增加，继发于AZA对IL-2基因启动子的去甲基化。重要的是，从AZA处理小鼠中收获的Treg具有抑制作用且随时间稳定，因为它们在二次移植实验中以高频率持续存在。最后，AZA并未消除移植物抗白血病效应（通过对转染以表达荧光素酶基因的THP-1细胞的生长抑制来评估）。总之，我们的数据表明，AZA可预防xGVHD，而不会消除移植物抗白血病效应。这些发现可为进一步研究AZA在接受异基因移植的急性髓系白血病患者中预防移植物抗宿主病提供基础。
