Anti-leukemic properties of aplysinopsin derivative EE-84 alone and in combination with BH3 mimetic A-1210477 (2)

Aplysinopsins are a class of marine indole alkaloids that exhibit a wide range of biological activities such as prevention of neoplastic growth on an array of different cancer cell lines. Although both the indole and N-benzyl moieties of aplysinopsins are known to possess anti-proliferative activity against cancer cells, their mechanism of action remains unclear. Through in vitro and in vivo proliferation and viability screening of newly synthesized aplysinopsin analogs on myelogenous leukemia cell lines and zebrafish toxicity tests as well as analysis of differential toxicity in non-cancerous RPMI 1788 cells, we identified EE-84 as a promising novel drug candidate against myeloid leukemia. This indole derivative demonstrated drug-likeness in agreement with Lipinski’s rule of five and was responsible for cell cycle dysregulation in K562 cells in line with its cytostatic effect. EE-84-treated K562 cells likewise underwent morphological changes suggesting mitochondrial dysfunction. Finally, we demonstrated the synergistic cytotoxic effect of EE-84 with a BH3 mimetic, the Mcl-1 inhibitor, A-1210477, against K562 cells, highlighting the inhibition of anti-apoptotic Bcl-2 proteins as a promising therapeutic approach against myeloid leukemia in combination with EE-84.阿普西诺辛（aplysinopsins）是一类海洋吲哚生物碱（marine indole alkaloids），具有广泛的生物学活性，例如可抑制多种癌细胞系的肿瘤生长。尽管阿普西诺辛的吲哚（indole）与N-苄基基团（N-benzyl moiety）均被证实可对癌细胞产生抗增殖活性（anti-proliferative activity），但其具体作用机制（mechanism of action）仍未明确。本研究通过对新合成的阿普西诺辛类似物开展髓系白血病（myelogenous leukemia）细胞系的体外、体内增殖与活力筛选，结合斑马鱼毒性试验（zebrafish toxicity tests），并针对非癌性RPMI 1788细胞开展差异毒性（differential toxicity）分析，最终筛选得到EE-84这一极具潜力的髓系白血病新型候选药物（drug candidate）。该吲哚衍生物符合类药五原则（Lipinski’s rule of five），具备成药性（drug-likeness），可诱导K562细胞发生细胞周期失调（cell cycle dysregulation），与其细胞生长抑制效应（cytostatic effect）相符。经EE-84处理的K562细胞同样出现形态学变化（morphological changes），提示线粒体功能异常（mitochondrial dysfunction）。最后，本研究证实EE-84与BH3模拟物（BH3 mimetic）、Mcl-1抑制剂（Mcl-1 inhibitor）A-1210477联用可对K562细胞产生协同细胞毒性作用（synergistic cytotoxic effect），表明靶向抑制抗凋亡Bcl-2家族蛋白（anti-apoptotic Bcl-2 proteins）并与EE-84联合使用，是一种极具前景的髓系白血病治疗策略。