Specific inhibitors of protein phosphatase 2A (PP2A) mediate anticancer effects by augmenting the tumor-killing activity of natural killer (NK) cells. In this study, new PP2A inhibitors, aminocytostatins A–E, were isolated from Kitasatospora sp. MJ654-NF4 and structurally characterized. Aminocytostatins are derivatives of cytostatin, which is a specific PP2A inhibitor isolated from the same organism, and aminocytostatins have a characteristic amino group within the lactone moiety. Compared to cytostatin, aminocytostatin A showed a stronger inhibitory activity against PP2A in vitro and augmented the tumor-killing activity of NK cells in vivo. Furthermore, a docking model was generated to demonstrate the favorable activities of aminocytostatin A.

蛋白磷酸酶 2A (PP2A) 的特异性抑制剂通过增强自然杀伤 (NK) 细胞的肿瘤杀伤活性来介导抗癌作用。在这项研究中，新的 PP2A 抑制剂氨基细胞抑素 A–E 是从Kitasatospora sp. 中分离出来的。MJ654-NF4 和结构表征。氨基细胞抑制素是细胞抑制素的衍生物，细胞抑制素是从同一生物体中分离出来的特异性 PP2A 抑制剂，氨基细胞抑制素在内酯部分内具有特征性氨基。与细胞抑素相比，氨基细胞抑素 A 在体外对 PP2A 表现出更强的抑制活性，并增强了体内 NK 细胞的肿瘤杀伤活性。此外，还生成了一个对接模型来证明氨基细胞抑素 A 的有利活性。