Epigenetic Modulation of GvHD and GvL

异基因造血干细胞移植（allo-HSCT）是目前唯一能治愈 复发/难治性白血病。allo-HSCT治疗血液系统恶性肿瘤的益处是 主要来源于移植物抗白血病（GvL）效应，该效应由存在于 骨髓移植不幸的是，介导有益GvL效应的相同供体T细胞也可以 导致移植物抗宿主病（GvHD），这是allo-HSCT的主要危及生命的并发症。管理 GvHD的威胁，同时最大限度地提高有益的GvL效应将扩大范围和有用性， 在allo-HSCT程序中，CD 4 + CD 25 + FOXP 3+调节性t细胞（TcR）已被证明可以预防GvHD。 通过抑制同种异体反应性供体T细胞而不牺牲GvL的临床前研究， 很有希望的治疗方案不幸的是，有几个局限性阻碍了TdR的常规临床使用： 1)外周血中低循环数的TcR，2）体外培养后抑制剂活性的丧失， 扩增和3）缺乏纯化体外扩增的Treg所必需的Treg特异性表面标志物。我们 先前报道，DNA甲基转移酶抑制剂阿扎胞苷（AzaC）诱导Foxp 3表达， 并增加体内供体TvL，从而减轻GvHD而不消除鼠allo-HSCT中的GvL。 模型令人惊讶的是，我们发现AzaC介导的GvHD抑制不依赖于Foxp 3，Foxp 3在GvHD中起作用。 Treg功能的主调节器。我们确定了三个候选基因，这些基因在大肠杆菌中被AzaC高度上调。 抗CD 3/CD 28珠和APC激活的CD 4 +/CD 25- T细胞，可能是导致 基于全基因组RNA谱分析的AzaC诱导的TcR的抑制功能。我们假设 AzaC将在人类T细胞中诱导类似的免疫调节作用。在这个项目中，我们将 评估AzaC在接受异基因干细胞移植的AML和MDS患者中的安全性和有效性 移植（目的1），并将进行机制研究，以确定如何AzaC和其他DNMT 1抑制剂 在体外和体内发挥其对GvHD和GvL的免疫调节作用。(Aim 2）。

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for patients with relapsed/refractory leukemia. The therapeutic benefits of allo-HSCT for hematologic malignancies are primarily derived from a graft-versus-leukemia (GvL) effect that is mediated by mature donor T cells present in the bone marrow graft. Unfortunately, the same donor T cells that mediate the beneficial GvL effect can also cause graft-versus-host disease (GvHD), the major life-threatening complication of allo-HSCT. Managing the threat of GvHD while maximizing the beneficial GvL effect would broaden the scope and usefulness of allo-HSCT procedures, CD4+CD25+FOXP3+ regulatory t cells (Tregs) have been shown to prevent GvHD in preclinical studies by suppressing alloreactive donor T cells without sacrificing GvL, thereby providing a promising treatment option. Unfortunately, several limitations have prevented the routine clinical use of Tregs: 1) the low circulating numbers of Tregs in peripheral blood, 2) loss of suppressor activity following in vitro expansion and 3) the lack of Treg-specific surface markers necessary to purify in vitro expanded Tregs. We previously reported that the DNA methyltransferase inhibitor azacitidine (AzaC)-induced Foxp3 expression and increased donor Tregs in vivo, thereby mitigating GvHD without abrogating GvL in a murine allo-HSCT model. Surprisingly, we found that AzaC-mediated suppression of GvHD was independent of Foxp3, the master regulator of Treg function. We identified three candidate genes that are highly upregulated by AzaC in anti-CD3/CD28 bead- and APC-activated CD4+/CD25- T cells and which might be responsible for the suppressor function of AzaC-induced Tregs based on genome-wide RNA profiling analyses. We hypothesize that AzaC will induce similar immunomodulatory effects in human T cells. In this SPORE project we will assess the safety and efficacy of AzaC in patients with AML and MDS undergoing allogeneic stem cell transplant (Aim 1) and will perform mechanistic studies to determine how AzaC and other DNMT1 inhibitors exert their immunomodulatory effects on GvHD and GvL in vitro and in vivo. (Aim 2).