Precision Targeting of <i>pten</i>-Null Triple-Negative Breast Tumors Guided by Electrophilic Metabolite Sensing

Off-target effects continue to impede disease interventions, particularly when targeting a specific protein within a family of similar proteins, such as kinase isoforms that play tumor-subtype-specific roles in cancers. Exploiting the specific electrophilic-metabolite-sensing capability of Akt3, versus moderate or no sensing, respectively, by Akt2 and Akt1, we describe a first-in-class functionally Akt3-selective covalent inhibitor [MK-H­(F)­NE], wherein the electrophilic core is derived from the native reactive lipid metabolite HNE. Mechanistic profiling and pathway interrogations point to retention of the metabolite’s structureas opposed to implicit electrophilicityas being essential for biasing isoform preference, which we found translates to tumor-subtype specificity against pten-null triple-negative breast cancers (TNBCs). MK-H­(F)­NE further enables novel downstream target identification specific to Akt3-function in disease. In TNBC xenografts, MK-H­(F)­NE fares better than reversible pan-Akt-inhibitors and does not show commonly observed side-effects associated with Akt1-inhibition. Inhibitors derived from native-metabolite sensing are thus an enabling plan-of-action for unmasking kinase-isoform-biased molecular targets and tumor-subtype-specific interventions.脱靶效应（off-target effects）始终阻碍疾病干预的推进，尤其是在靶向一类相似蛋白家族中的特定蛋白时——例如在癌症中发挥肿瘤亚型特异性作用的激酶同工型（kinase isoforms）。我们利用Akt3所具备的特异性亲电代谢物感应能力——而Akt2与Akt1仅具备中等程度或完全不具备该感应能力——报道了一款首创的功能性Akt3选择性共价抑制剂（covalent inhibitor）[MK-H(F)NE]，其亲电核心（electrophilic core）源自天然反应性脂质代谢物HNE。机制表征分析与通路探究结果表明，保留该代谢物的结构——而非潜在亲电性——才是决定其同工型偏好的关键因素；我们发现这一特性可转化为针对PTEN缺失型三阴性乳腺癌（TNBC）的肿瘤亚型特异性作用。MK-H(F)NE还可用于鉴定疾病中与Akt3功能特异性相关的新型下游靶点。在TNBC肿瘤异种移植模型（xenografts）中，MK-H(F)NE的效果优于可逆性泛Akt抑制剂（reversible pan-Akt-inhibitors），且未出现Akt1抑制相关的常见副作用。由此可见，源自天然代谢物感应的抑制剂，为揭示激酶同工型偏好性分子靶点与开发肿瘤亚型特异性干预手段提供了可行的作用策略。