The epigenetic factors KAT6A (MOZ/MYST3) and KMT2A (MLL/MLL1) interact in normal hematopoiesis to regulate progenitors’ self-renewal. Both proteins are recurrently translocated in AML, leading to impairment of critical differentiation pathways in these malignant cells. We evaluated the potential of different KAT6A therapeutic targeting strategies to alter the growth of KAT6A and KMT2A rearranged AMLs. We investigated the action and potential mechanisms of the first-in-class KAT6A inhibitor, WM-1119 in KAT6A and KMT2A rearranged (KAT6Ar and KMT2Ar) AML using cellular (flow cytometry, colony assays, cell growth) and molecular (shRNA knock-down, CRISPR knock-out, bulk and single-cell RNA-seq, ChIP-seq) assays. We also used two novel genetic murine KAT6A models combined with the most common KMT2Ar AML, KMT2A::MLLT3 AML. In these murine models, the catalytic activity of KAT6A, or the whole protein, can be conditionally abrogated or deleted. These models allowed us to compare the effects of specific KAT6A KAT activity inhibition with the complete deletion of the whole protein. Finally, we also tested these therapeutic approaches on human AML cell lines and primary patient AMLs. We found that WM-1119 completely abrogated the proliferative and clonogenic potential of KAT6Ar cells in vitro. WM-1119 treatment was associated with a dramatic increase in myeloid differentiation program. The treatment also decreased stemness and leukemia pathways at the transcriptome level and led to loss of binding of the fusion protein at critical regulators of these pathways. In contrast, our pharmacologic and genetic results indicate that the catalytic activity of KAT6A plays a more limited role in KMT2Ar leukemogenicity, while targeting the whole KAT6A protein dramatically affects leukemic potential in murine KMT2A::MLLT3 AML. Our study indicates that inhibiting KAT6A KAT activity holds compelling promise for KAT6Ar AML patients. In contrast, targeted degradation of KAT6A, and not just its catalytic activity, may represent a more appropriate therapeutic approach for KMT2Ar AMLs.

中文翻译：

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尽管 KAT6 具有共同的遗传依赖性，但小抑制剂 WM-1119 有效靶向 KAT6A 重排的 AML，但不靶向 KMT2A 重排的 AML


表观遗传因子 KAT6A （MOZ/MYST3） 和 KMT2A （MLL/MLL1） 在正常造血中相互作用，调节祖细胞的自我更新。这两种蛋白在 AML 中反复易位，导致这些恶性细胞中的关键分化途径受损。我们评估了不同 KAT6A 治疗靶向策略改变 KAT6A 和 KMT2A 重排 AMLs 生长的潜力。我们使用细胞 （流式细胞术、集落测定、细胞生长） 和分子 （shRNA 敲除、CRISPR 敲除、批量和单细胞 RNA-seq、ChIP-seq） 测定研究了同类首创 KAT6A 抑制剂 WM-1119 在 KAT6A 和 KMT2A 重排 （KAT6Ar 和 KMT2Ar） AML 中的作用和潜在机制。我们还使用了两种新型遗传小鼠 KAT6A 模型联合最常见的 KMT2Ar AML KMT2A：：MLLT3 AML。在这些小鼠模型中，KAT6A 或整个蛋白质的催化活性可以被有条件地消除或删除。这些模型使我们能够比较特异性 KAT6A KAT 活性抑制与全蛋白完全缺失的效果。最后，我们还在人 AML 细胞系和原发性患者 AML 上测试了这些治疗方法。我们发现 WM-1119 在体外完全消除了 KAT6Ar 细胞的增殖和克隆形成潜力。WM-1119 治疗与髓系分化程序的显着增加有关。该治疗还在转录组水平上降低了干性和白血病途径，并导致融合蛋白在这些途径的关键调节因子处的结合丧失。 相比之下，我们的药理学和遗传学结果表明，KAT6A 的催化活性在 KMT2Ar 白血病发生性中的作用更有限，而靶向整个 KAT6A 蛋白显着影响小鼠 KMT2A：：MLLT3 AML 中的白血病潜力。我们的研究表明，抑制 KAT6A KAT 活性对 KAT6Ar AML 患者具有令人信服的前景。相比之下，KAT6A 的靶向降解，而不仅仅是其催化活性，可能代表了 KMT2Ar AML 的更合适的治疗方法。