Perturbing LSD1 and WNT rewires transcription to synergistically induce AML differentiation (CUT&RUN)

Impaired differentiation is a hallmark of myeloid malignancies1,2. Therapies that enable cells to circumvent the differentiation block, such as all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), are by and large curative in acute promyelocytic leukaemia3, but whether 'differentiation therapy' is a generalizable therapeutic approach for acute myeloid leukaemia (AML) and beyond remains incompletely understood. Here we demonstrate that simultaneous inhibition of the histone demethylase LSD1 (LSD1i) and the WNT pathway antagonist GSK3 kinase4 (GSK3i) robustly promotes therapeutic differentiation of established AML cell lines and primary human AML cells, as well as reducing tumour burden and significantly extending survival in a patient-derived xenograft mouse model. Mechanistically, this combination promotes differentiation by activating genes in the type I interferon pathway via inducing expression of transcription factors such as IRF7 (LSD1i) and the co-activator ß-catenin (GSK3i), and their selective co-occupancy at targets such as STAT1, which is necessary for combination-induced differentiation. Combination treatment also suppresses the canonical, pro-oncogenic WNT pathway and cell cycle genes. Analysis of datasets from patients with AML suggests a correlation between the combination-induced transcription signature and better prognosis, highlighting clinical potential of this strategy. Collectively, this combination strategy rewires transcriptional programs to suppress stemness and to promote differentiation, which may have important therapeutic implications for AML and WNT-driven cancers beyond AML. Overall design: THP-1 cell treated with DMSO, GSK-LSD1, LY2090314 and combination of both inhibitors and cells prepared for CUT&RUN for IRF7 and ß-catenin.

髓系恶性肿瘤的标志性特征之一是细胞分化受损¹,²。能够使肿瘤细胞绕过分化阻滞的治疗手段，例如全反式维甲酸（all-trans retinoic acid, ATRA）与三氧化二砷（arsenic trioxide, ATO），在急性早幼粒细胞白血病中大体可实现治愈³，但“分化疗法”是否可作为急性髓系白血病（acute myeloid leukaemia, AML）及其他相关疾病的通用治疗策略，目前仍未完全明确。
本研究证实，同时抑制组蛋白去甲基化酶LSD1（histone demethylase LSD1, LSD1i）与WNT通路拮抗剂糖原合成激酶3（GSK3激酶, GSK3i），可显著促进已建立的AML细胞系及原代人AML细胞的治疗性分化，同时在患者来源异种移植小鼠模型中降低肿瘤负荷并显著延长小鼠生存期。
机制层面，该联合疗法通过诱导干扰素调节因子7（IRF7，受LSD1i调控）与共激活因子β-连环蛋白（β-catenin，受GSK3i调控）等转录因子的表达，激活I型干扰素通路相关基因；且二者可在信号转导与转录激活因子1（STAT1）等靶位点选择性共结合，这一过程是联合疗法诱导分化所必需的。此外，联合治疗还可抑制经典促癌性WNT通路及细胞周期相关基因。
对AML患者数据集的分析显示，联合疗法诱导的转录特征与更佳预后存在相关性，凸显了该策略的临床应用潜力。
综上，该联合策略可重编程转录程序，抑制干细胞干性并促进细胞分化，其对AML及非AML的WNT驱动型癌症均具有重要的治疗价值。
整体实验设计：将THP-1细胞系分别用二甲基亚砜（DMSO）、GSK-LSD1、LY2090314以及两种抑制剂联合处理，随后收集细胞用于IRF7与β-连环蛋白的染色质靶向切割与释放测序（CUT&RUN）分析。