Mechanisms whereby IFN-gamma sensitizes AML to the graft-vs-leukemia effect

抽象的。 异基因造血干细胞移植（alloSCT）是最常应用于造血干细胞移植的治愈性疗法。 治疗急性髓细胞白血病（AML）患者。同种异体反应性ab T细胞的后代在 同种异体移植物可以杀死受体白血病细胞，从而介导移植物抗白血病效应（GVL）。然而，尽管如此， 表明GVL不足的疾病复发是移植后死亡的唯一最常见原因。 尽管所有白血病都表达同种异体抗原，但GVL耐药和敏感性在不同类型的白血病中并不相等。 例如，慢性期慢性髓细胞性白血病（CP-CML）是非常敏感的GVL，而 急变期CML（BC-CML）是GVL抗性的，尽管共享共同的生物学。同样，AML和急性 淋巴母细胞白血病是相对GVL抗性的。因为GVL电阻和敏感性与 类肿瘤，我们推断它们是白血病细胞的内在特性。因此，我们建立了GVL 针对用真实的人癌基因创建的mCP-CML和mBC-CML小鼠模型。通过 我们发现mBC-CML需要IFN-γR才能产生有效的GVL， 刺激，而GVL对STAT 1/STAT 2-/- mCP-CML是完全完整的，其不能对任何类型的刺激产生应答。 的IFN IFN-γR-/-MLL-AF 9也是GVL抗性的。这些数据表明，有效的GVL抗成髓细胞 白血病需要高强度的同种异体反应性T细胞应答，产生IFN-g， 不产生大量IFN-g的郁积T细胞应答可有效对抗CP-CML。这些结果 也强烈提示IFN-γ的递送，与同种异体反应性或白血病反应性T细胞， 会产生重大的临床影响然而，关键问题需要得到回答，以最佳地应用IFN-g或 在临床上诱导其某些作用的药剂。首先，虽然所有AML亚型都有一些共同的生物学特征， 在驱动基因中存在大量异质性。因此，了解哪些AML 分子亚型需要IFN-g用于最佳GVL。我们的目标是通过使用CRISPR-Cas9来删除IFN-γ， 来自表达关键AML驱动因子的复合基因编辑小鼠中发展的可移植白血病的γR 基因，有时与基因缺失结合。我们已经成功地编辑了来自 JAK2V617F/p53-/-和FLT3-ITD/DNMT3-/-/NPM1c AML。第二，IFN-g是一种具有多效性的钝性工具 可能导致移植物抗宿主病因此，我们的目标是了解在何种同种免疫条件下， IFN-g是必需的，以及什么样的特定下游效应对于AML细胞对GVL敏感是必不可少的。我们有 已经开发出恢复关键IFN-γ诱导基因（如CIITA、NLRC 5、ICAM-1）表达的方法 IFN-γR-/-白血病，以具体询问其相关性。会发现更多的目标 通过单细胞RNAseq，专注于IFN-γ诱导的干细胞亚群中的基因表达变化 细胞质量。这些靶点可以在IFN-γR白血病中缺失或表达，以进一步确定它们的功能。 重要性

Abstract. Allogeneic hematopoietic stem cell transplantation (alloSCT) is a curative therapy most commonly applied in treatment of patients with acute myeloblastic leukemia (AML). The progeny of alloreactive ab T cells in the allograft can kill recipient leukemia cells, thereby mediating the graft-vs-leukemia effect (GVL). Nevertheless, disease relapse, indicative of insufficient GVL, is the single most common cause of death post-transplant. GVL-resistance and sensitivity are not equal across classes of leukemias, despite all expressing alloantigens. For example, chronic phase chronic myelogenous leukemia (CP-CML) is exquisitely GVL-sensitive whereas blast crisis CML (BC-CML) is GVL-resistant, despite sharing common biology. Likewise, AML and acute lymphoblastic leukemia are relatively GVL-resistant. Because GVL-resistance and -sensitivity track with the class of neoplasm, we reasoned that they are leukemia cell-intrinsic properties. We therefore established GVL against mouse models of mCP-CML and mBC-CML created with authentic human oncogenes. Through the creation of gene-deficient leukemias we discovered that for effective GVL, mBC-CML requires IFN-γR stimulation whereas GVL is fully intact against STAT1/STAT2-/- mCP-CML that cannot respond to any type of IFN. IFN-γR-/- MLL-AF9 was also GVL-resistant. These data indicate that effective GVL against myeloblastic leukemias requires a high magnitude alloreactive T cell response that generates IFN-g whereas a more smoldering T cell response that does not create much IFN-g can be effective against CP-CML. These results also strongly suggest that the delivery of IFN-g, in conjunction with alloreactive or leukemia-reactive T cells, would have a major clinical impact. However, key questions need to be answered to optimally apply IFN-g or agents that induce some of its effects in the clinic. First, while all AML subtypes share some common biology, there is substantial heterogeneity in driver genes. It will therefore be critical to understand which AML molecular subtypes require IFN-g for optimal GVL. We aim to do so by using CRISPR-Cas9 to delete the IFN- γR from transplantable leukemias that develop in compound gene-edited mice that express key AML-driver genes, sometimes in conjunction with a gene deletion. We have already successfully edited the IFN-γR from JAK2V617F/p53-/- and FLT3-ITD/DNMT3-/-/NPM1c AMLs. Second, IFN-g is a blunt tool with pleiotropic effects that could promote graft-vs-host disease. Therefore, we aim to understand under what alloimmune conditions IFN-g is required and what specific downstream effects are essential to sensitize AML cells to GVL. We have already developed approaches to restore expression of key IFN-g-induced genes (e.g. CIITA, NLRC5, ICAM-1) to IFN-γR-/- leukemias in order to specifically interrogate their relevance. Further targets will be discovered through single cell RNAseq, focusing on IFN-g-induced gene expression changes in subpopulations with stem cell qualities. These targets could then be deleted or expressed in IFN-γR leukemias to further define their importance.