Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Center for Autoimmune Genetics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Sci Transl Med. 2022 Mar 9;14(635):eabb7695. doi: 10.1126/scitranslmed.abb7695.
Dysregulation of innate immune signaling pathways is implicated in various hematologic malignancies. However, these pathways have not been systematically examined in acute myeloid leukemia (AML). We report that AML hematopoietic stem and progenitor cells (HSPCs) exhibit a high frequency of dysregulated innate immune-related and inflammatory pathways, referred to as oncogenic immune signaling states. Through gene expression analyses and functional studies in human AML cell lines and patient-derived samples, we found that the ubiquitin-conjugating enzyme UBE2N is required for leukemic cell function in vitro and in vivo by maintaining oncogenic immune signaling states. It is known that the enzyme function of UBE2N can be inhibited by interfering with thioester formation between ubiquitin and the active site. We performed in silico structure-based and cellular-based screens and identified two related small-molecule inhibitors UC-764864/65 that targeted UBE2N at its active site. Using these small-molecule inhibitors as chemical probes, we further revealed the therapeutic efficacy of interfering with UBE2N function. This resulted in the blocking of ubiquitination of innate immune- and inflammatory-related substrates in human AML cell lines. Inhibition of UBE2N function disrupted oncogenic immune signaling by promoting cell death of leukemic HSPCs while sparing normal HSPCs in vitro. Moreover, baseline oncogenic immune signaling states in leukemic cells derived from discrete subsets of patients with AML exhibited a selective dependency on UBE2N function in vitro and in vivo. Our study reveals that interfering with UBE2N abrogates leukemic HSPC function and underscores the dependency of AML cells on UBE2N-dependent oncogenic immune signaling states.
先天免疫信号通路的失调与各种血液恶性肿瘤有关。然而，这些通路在急性髓系白血病（AML）中尚未得到系统研究。我们报告称，AML 造血干/祖细胞（HSPC）表现出高频失调的先天免疫相关和炎症通路，称为致癌免疫信号状态。通过人类 AML 细胞系和患者来源样本中的基因表达分析和功能研究，我们发现泛素连接酶 UBE2N 通过维持致癌免疫信号状态，在体外和体内维持白血病细胞的功能。已知 UBE2N 的酶功能可以通过干扰泛素与活性位点之间的硫酯形成来抑制。我们进行了基于结构的计算机模拟和基于细胞的筛选，并鉴定了两种相关的小分子抑制剂 UC-764864/65，它们靶向 UBE2N 的活性位点。使用这些小分子抑制剂作为化学探针，我们进一步揭示了干扰 UBE2N 功能的治疗效果。这导致阻断了人 AML 细胞系中先天免疫和炎症相关底物的泛素化。UBE2N 功能的抑制通过促进白血病 HSPC 的细胞死亡而不影响正常 HSPC，从而破坏致癌免疫信号。此外，来自 AML 患者不同亚群的白血病细胞中固有的致癌免疫信号状态在体外和体内均表现出对 UBE2N 功能的选择性依赖。我们的研究表明，干扰 UBE2N 可破坏白血病 HSPC 的功能，并强调了 AML 细胞对 UBE2N 依赖性致癌免疫信号状态的依赖。
