作者:Theodosia Teo、Frankie Lam、Mingfeng Yu、Yuchao Yang、Sunita K. C. Basnet、Hugo Albrecht、Matthew J. Sykes、Shudong Wang
DOI:10.1124/mol.115.098012
日期:2015.8
The Ras/Raf/MAPK and PI3K/Akt/mTOR pathways are key signaling cascades involved in the regulation of cell proliferation and survival, and have been implicated in the pathogenesis of several types of cancers, including acute myeloid leukemia (AML). The oncogenic activity of eIF4E driven by the Mnk kinases is a convergent determinant of the two cascades, suggesting that targeting the Mnk/eIF4E axis may provide therapeutic opportunity for the treatment of cancer. Herein, a potent and selective Mnk2 inhibitor (MNKI-85) and a dual-specific Mnk1 and Mnk2 inhibitor (MNKI-19), both derived from a thienopyrimidinyl chemotype, were selected to explore their antileukemic properties. MNKI-19 and MNKI-85 are effective in inhibiting the growth of AML cells that possess an M5 subtype with FLT3-internal tandem duplication mutation. Further mechanistic studies show that the downstream effects with respect to the selective Mnk1/2 kinase inhibition in AML cells causes G1 cell cycle arrest followed by induction of apoptosis. MNKI-19 and MNKI-85 demonstrate similar Mnk2 kinase activity and cellular antiproliferative activity but exhibit different time-dependent effects on cell cycle progression and apoptosis. Collectively, this study shows that pharmacologic inhibition of both Mnk1 and Mnk2 can result in a more pronounced cellular response than targeting Mnk2 alone. However, MNKI-85, a first-in-class inhibitor of Mnk2, can be used as a powerful pharmacologic tool in studying the Mnk2/eIF4E-mediated tumorigenic mechanism. In conclusion, this study provides a better understanding of the mechanism underlying the inhibition of AML cell growth by Mnk inhibitors and suggests their potential utility as a therapeutic agent for AML.
Ras/Raf/MAPK 和 PI3K/Akt/mTOR 通路是参与细胞增殖和存活调节的关键信号级联,并且与多种癌症的发病机制有关,包括急性髓系白血病 (AML)。 Mnk 激酶驱动的 eIF4E 致癌活性是两个级联的汇聚决定因素,表明靶向 Mnk/eIF4E 轴可能为癌症的治疗提供治疗机会。在此,选择了一种有效且选择性的 Mnk2 抑制剂 (MNKI-85) 和一种双特异性 Mnk1 和 Mnk2 抑制剂 (MNKI-19),两者均源自噻吩并嘧啶基化学型,以探索其抗白血病特性。 MNKI-19 和 MNKI-85 可有效抑制具有 FLT3 内部串联重复突变的 M5 亚型的 AML 细胞的生长。进一步的机制研究表明,AML 细胞中选择性 Mnk1/2 激酶抑制的下游效应导致 G1 细胞周期停滞,随后诱导细胞凋亡。 MNKI-19 和 MNKI-85 表现出相似的 Mnk2 激酶活性和细胞抗增殖活性,但对细胞周期进程和细胞凋亡表现出不同的时间依赖性影响。总的来说,这项研究表明,与单独针对 Mnk2 相比,同时抑制 Mnk1 和 Mnk2 可以产生更明显的细胞反应。然而,MNKI-85 作为首创的 Mnk2 抑制剂,可作为研究 Mnk2/eIF4E 介导的致瘤机制的强大药理学工具。总之,这项研究提供了对 Mnk 抑制剂抑制 AML 细胞生长的机制的更好理解,并表明它们作为 AML 治疗剂的潜在用途。