Pharmaceutical inhibition of RAS overcomes cytokine mediated resistance to FLT3 inhibition in FLT3-ITD+ AML [ChIP-seq II]

AML is characterised by a variety of co-occurring driver mutations in genes associated with cell signallingand growth regulationsuch as the FLT3-ITD. Inhibitors targeting FLT3 (FLT3i) are beingused to treat FLT3-ITD+ patients but most relapse.By profiling the gene regulatory networks of samples from patients before and after FLT3i treatment weobservedan increase in AP-1 mediated and a loss of RUNX1 mediated connections in treatment resistant cells. Treatmentinducesupregulation of signalling pathway genesindicatingthat cytokines mediate resistance to FLT3i, with IL-3 playing a major role. IL3 rescues survival by counteracting FLT3i mediated globalRUNX1 degradation and adown-regulationof bindingof RUNX1 in chromatin.To identify inhibitors which bypass the RUNX1 barrier we inhibitedMAPK signalling with a novel pan-RAS inhibitor which overcomes cytokine mediated resistance.Our data show (I) that cytokinesinstructAML maintenance via the stabilisation of transcriptional regulators and (ii)pan-RAS drugs bypass thisbarrier, suggesting a novel approach to treatment of AML. ChIP-Seq for RUNX1 in the FLT3-ITD cell line MV411, transfected with a doxycycline inducible dominant-negative FOS (dnFOS) or empty vector - and with or without doxycycline induction

急性髓系白血病（Acute Myeloid Leukemia, AML）以伴随多种与细胞信号转导及生长调控相关基因的驱动突变为特征，例如FLT3-ITD。靶向FLT3的抑制剂（FLT3 inhibitor, FLT3i）目前被应用于FLT3-ITD阳性患者的治疗，但多数患者会出现复发。通过对FLT3i治疗前后的患者样本进行基因调控网络分析，我们观察到在治疗耐药细胞中，AP-1介导的连接通路显著增强，而RUNX1介导的连接通路出现缺失。治疗可诱导信号通路基因上调，表明细胞因子介导了对FLT3i的耐药性，其中IL-3发挥主要作用。IL-3可通过拮抗FLT3i介导的全局性RUNX1降解，并下调RUNX1在染色质上的结合，来挽救细胞存活。为筛选能够绕过RUNX1耐药屏障的抑制剂，我们使用新型泛RAS抑制剂阻断MAPK信号通路，该药物可有效克服细胞因子介导的耐药性。我们的研究数据显示：(i) 细胞因子通过稳定转录调控因子来维持AML的发生发展；(ii) 泛RAS类药物可绕过这一屏障，为AML的治疗提供了全新策略。本数据集包含在FLT3-ITD细胞系MV411中开展的RUNX1染色质免疫共沉淀测序（Chromatin Immunoprecipitation Sequencing, ChIP-Seq）实验数据，该细胞系被转染了多西环素诱导型显性负FOS（dnFOS）或空载体，并设置了多西环素诱导与未诱导两组。