PO.ET09.01 · 实验与分子治疗
H11是一种同类首创的双功能HDAC和自噬抑制剂,具有强效抗白血病活性
H11 is a first-in-class bifunctional HDAC and autophagy inhibitor with potent antileukemic activity
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
急性髓系白血病(AML)是一种高度侵袭性的血液系统恶性肿瘤,其特征为破坏造血功能的未成熟髓系原始细胞的蓄积。尽管标准化疗可实现初始缓解,但复发频繁,持久缓解仍不常见。这凸显了对能够克服既定耐药机制的新型治疗策略的需求。表观遗传稳态的破坏是AML发病机制的共同特征,为靶向治疗提供了机会。组蛋白去乙酰化酶(HDAC)抑制剂是一类可诱导表观遗传重编程的药物,先前已展现出抗白血病活性。然而,其疗效因细胞保护性自噬的激活而减弱。因此,同时阻断HDAC活性和自噬通量是增强治疗获益的合理途径。为此,我们研发了H11,一种同类首创的双功能小分子,经设计可同时抑制HDAC并抑制自噬。H11在基因多样的AML模型及来自患者的原代AML样本(包括具有FLT3-ITD和p53功能丧失等不良特征者)中强效降低活力并触发凋亡。H11在对一线治疗耐药的模型中保留了强效活性,表明其具有克服表观遗传和溶酶体介导耐药机制的潜力。重要的是,H11展现出强大的治疗选择性,对正常CD34+骨髓祖细胞的影响非常有限。机制研究表明H11可强效抑制HDAC,其证据为整体组蛋白乙酰化增加,同时伴有自噬降解受损,表现为p62蓄积、溶酶体去酸化和自噬通量阻断。H11治疗还降低了致癌转录因子c-Myc的表达并增加了CDKN1A(p21),这与表观遗传重编程和AML生存回路的破坏相一致。由于表观遗传失调是AML的标志,我们接下来评估了H11与FDA批准的低甲基化药物azacitidine(AZA)联用。H11-AZA联合产生了强烈的协同作用,显著增强了在多种AML细胞系中的细胞毒性,并在原位FLT3-ITD+ AML小鼠异种移植模型中显著延长了总生存期。总之,这些发现确立了H11作为一种同类首创的HDAC-自噬双重抑制剂,其整合表观遗传调控与自噬抑制以促进凋亡并破坏适应性AML生存通路。这一协调的作用机制凸显H11作为一种有前景的新一代治疗药物,具有改善AML患者临床结局的强大潜力。
查看英文原文 English abstract
Acute myeloid leukemia (AML) is a highly aggressive hematologic malignancy characterized by the accumulation of immature myeloid blasts that disrupt hematopoiesis. Although initial remissions can be achieved with standard chemotherapy, relapse is frequent and durable responses remain uncommon. This underscores the need for new therapeutic strategies that can overcome established resistance mechanisms. Disruption of epigenetic homeostasis is a common feature of AML pathogenesis and offers an opportunity for targeted therapy. Histone deacetylase (HDAC) inhibitors are one class of agents that induce epigenetic reprogramming and have previously demonstrated antileukemic activity. However, their efficacy is blunted by the activation of cytoprotective autophagy. Simultaneous blockade of HDAC activity and autophagic flux therefore represents a rational approach to enhance therapeutic benefit. To address this, we developed H11, a first-in-class bifunctional small molecule engineered to concurrently inhibit HDACs and suppress autophagy. H11 potently reduced viability and triggered apoptosis across genetically diverse AML models and primary AML specimens from patients including those with adverse features such as FLT3-ITD and loss of p53 function. H11 retained potent activity in models resistant to frontline therapies, indicating its potential to overcome both epigenetic and lysosomal-mediated resistance mechanisms. Importantly, H11 demonstrated strong therapeutic selectivity with very limited effects against normal CD34+ bone marrow progenitors. Mechanistic studies demonstrated robust HDAC inhibition, evidenced by increased global histone acetylation, coupled with impaired autophagic degradation, reflected by p62 accumulation, lysosomal deacidification, and blocked autophagic flux. H11 treatment also decreased the expression of the oncogenic transcription factor c-Myc and increased CDKN1A (p21), consistent with epigenetic reprogramming and disruption of AML survival circuitry. Because epigenetic dysregulation is a hallmark of AML, we next evaluated H11 in combination with the FDA-approved hypomethylating agent azacitidine (AZA). The H11-AZA combination produced strong synergy, markedly enhancing cytotoxicity across multiple AML cell lines and significantly extending overall survival in an orthotopic FLT3-ITD+ mouse xenograft model of AML. Together, these findings establish H11 as a first-in-class dual HDAC-autophagy inhibitor that integrates epigenetic modulation with autophagy suppression to promote apoptosis and disrupt adaptive AML survival pathways. This coordinated mechanism of action highlights H11 as a promising next-generation therapeutic with strong potential to improve clinical outcomes in patients with AML.
利益披露 Disclosure
N. L. Hakim, None..
C. M. Espitia, None..
S. Sureshkumar, None..
M. Gamble, None..
B. Fangchao, None..
W. Wang, None..
K. Kelly, None..
J. S. Carew, None..
S. T. Nawrocki, None.