Rational p300/CREBBP KAT inhibition in AML

急性髓系白血病(AML)是一种侵袭性血癌，5年存活率只有30%，预后很差。急性髓细胞白血病具有在治疗下持续进化和适应的非凡能力。这一特征是通过调节表观遗传过程而受到严格控制的。由于表观遗传调节因子在急性髓细胞白血病中通常发生突变，这一特性指定以表观遗传修饰为目标的药物是治疗此类癌症的合适疗法。然而，以表观遗传修饰物为靶点的单一化合物的临床试验往往因初始缺乏反应或随后获得非遗传(机械性)适应而失败。通过这个项目，我打算避免目前正在出现的一类表观遗传调节剂-p300/CREBBP赖氨酸乙酰转移酶(KAT)抑制剂-的类似结果。为此，我们将首先对p300/CREBBP在不同AML模型中的作用进行全面的机械和功能解构，然后对p300/CREBBP Kat抑制在治疗幼稚和耐药环境中的影响进行综合评估。在方法上，我们将在多个正交系统(细胞系、原代人类样本和小鼠模型)中使用一系列最新的表观基因组学、蛋白质组学和功能技术。这种综合方法将在治疗反应和耐药性发展过程中显示AML类型在染色质的特定动态，同时也将实验偏差降至最低。我们的初步结果强调了这种复杂的机械解构的必要性。这些显示了p300/CREBBP先前未预料到的抑制功能，在所有测试的AML中，有50%的P300/CREBBP可以抵消细胞死亡诱导的干扰素反应。这是令人惊讶的，因为p300/CREBBP在急性髓系白血病中主要是因为它们的染色质激活功能而被研究。我们在初步数据中表明，对p300/CREBBP的依赖可以综合增强，例如通过长期抑制溴域和端外(BET)蛋白。我们还表明，对p300/CREBBP抑制剂的非遗传耐药性导致对其他可药物表观遗传调节剂的更高依赖，例如典型的染色质重塑BAF复合体。我建议利用这些见解(以及我们将在本项目的第一部分获得的结果)，将p300/CREBBP Kat抑制剂包括在合理的序贯治疗策略中，并使用3-4种表观遗传抑制剂，从而通过逐渐降低可塑性来指导AML的治疗轨迹。我推测，该项目将对p300/CREBBP Kat抑制剂治疗AML的临床成功实施产生关键影响，并将进一步为其他下一代表观遗传调节剂提供范例。

Acute myeloid leukemias (AML) are aggressive blood cancers with a dismal prognosis of only 30% survival rate at 5 years. AML possess an extraordinary capacity to evolve continuously and adapt under treatment. This characteristic is critically controlled through adjustments of epigenetic processes. Along the fact that epigenetic regulators are commonly mutated in AML, this property designates drugs targeting epigenetic modifications as suitable therapies for such cancers. However, clinical trials with single compounds targeting epigenetic modifiers have often disappointed due to either a primary lack of response, or the subsequent acquisition of non-genetic (mechanistic) adaptation. With this project, I intend to avoid a similar outcome for a currently emerging class of epigenetic modulators – p300/CREBBP lysine acetyltransferase (KAT) inhibitors. To do so, we will initially perform a comprehensive mechanistic and functional deconstruction of the p300/CREBBP roles in diverse models of AML, and then conduct an integrative assessment of the effects of p300/CREBBP KAT inhibition in both treatment-naïve and -resistant settings. Methodologically, we will use a series of up-to-date epigenomic, proteomic and functional techniques in multiple orthogonal systems (cell lines, primary human samples and murine models). This integrative approach will show AML type-specific dynamics at chromatin during treatment response and development of resistance, while also minimizing experimental biases. The necessity of such a complex mechanistic deconstruction is emphasized in our preliminary results. These show a previously unanticipated repressive function of p300/CREBBP to counteract a cell-death inducing interferon response in 50% of all tested AMLs. This is surprising, because p300/CREBBP have mostly been studied in AML for their chromatin-activating functions. We show in our preliminary data that the reliance on p300/CREBBP can be enhanced synthetically, for example through chronic inhibition of bromodomain and extraterminal (BET) proteins. We also show that non-genetic resistance to p300/CREBBP inhibitors causes higher dependency on other druggable epigenetic modulators, such as the canonical chromatin remodeling BAF complex. I propose to exploit these insights (and also results that we will obtain in our first parts of this project) by including p300/CREBBP KAT inhibitors in a rational sequential treatment strategy with 3-4 epigenetic inhibitors, and thus guide treatment trajectories in AML by gradually decreasing plasticity. I hypothesize that this project will critically influence the successful clinical implementation of p300/CREBBP KAT inhibitors to treat AML and will further serve as an example for other next-generation epigenetic modulators.