Identification of a novel synergistic induction of cell death by Smac mimetic and HDAC inhibitors in acute myeloid leukemia cells
Identification of a novel synergistic induction of cell death by Smac mimetic and HDAC inhibitors in acute myeloid leukemia cells
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DOI：
10.1016/j.canlet.2015.05.020
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发表时间：
2015-09-28
期刊：
影响因子：
9.7
通讯作者：
Fulda, Simone
中科院分区：
文献类型：
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作者：
Steinwascher, Sofie;Nugues, Anne-Lucie;Fulda, Simone
凋亡抑制蛋白(IAP)在急性髓系白血病(AML)中高水平表达，参与抵抗细胞程序性死亡。在这里，我们报告了小分子Smac模拟物BV6对IAP蛋白的抑制作用与组蛋白脱乙酰酶(HDAC)抑制剂(HDACIs)如MS275或SAHA以协同方式触发AML细胞系的细胞死亡，通过计算结合指数(CI)。此外，BV6和HDACI共同触发DNA片段化，这是凋亡细胞死亡的标志，并抑制AML细胞的长期克隆生存。相反，等摩尔浓度的BV6和MS275或SAHA不能协同诱导正常外周血淋巴细胞(PBL)的细胞死亡，强调了这种联合治疗的一些肿瘤细胞选择性。肿瘤坏死因子(TNF)α阻断抗体Enbrel的加入显著减少了BV6/MS275诱导的大多数AML细胞系的细胞死亡，表明自分泌/旁分泌TNFα信号参与了细胞死亡。值得注意的是，广谱caspase抑制剂N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone(zVAD.fmk)不能挽救MV4-11、Molm13和OCI-AML3细胞，甚至不能增强BV6/MS275介导的细胞死亡，而ZVAD.fmk则减少BV6/MS275诱导的NB4细胞死亡。Annexin-V/PI双重染色显示BV6/MS275共处理显著增加了双阳性细胞的百分比。值得注意的是，在zVAD.fmk存在的情况下，受体相互作用蛋白(RIP)1抑制剂NEC-1(NEC-1)或混合血统激酶结构域样蛋白(MLKL)抑制剂NSA显著减少BV6/MS275诱导的细胞死亡，表明当caspase被抑制时，BV6/MS275联合治疗触发坏死性下垂。因此，BV6与HDACIs协同作用可诱导AML细胞死亡，并可通过将坏死下垂作为调节细胞死亡的替代途径，至少在几个AML细胞系中绕过凋亡抵抗。BV6和HDACIs新的协同作用的发现对于AML新的治疗策略的开发具有重要的意义。(C)2015爱思唯尔爱尔兰有限公司。保留所有权利。
Inhibitor of Apoptosis (IAP) proteins are expressed at high levels in acute myeloid leukemia (AML) and contribute to resistance to programmed cell death. Here, we report that inhibition of IAP proteins by the small-molecule Smac mimetic BV6 acts together with histone deacetylase (HDAC) inhibitors (HDACIs) such as MS275 or SAHA to trigger cell death in AML cell lines in a synergistic manner, as underscored by calculation of combination index (CI). Also, BV6 and HDACIs cooperate to trigger DNA fragmentation, a marker of apoptotic cell death, and to suppress long-term clonogenic survival of AML cells. In contrast, equimolar concentrations of BV6 and MS275 or SAHA do not synergize to elicit cell death in normal peripheral blood lymphocytes (PBLs), emphasizing some tumor cell selectivity of this combination treatment. Addition of the tumor necrosis factor (TNF)alpha-blocking antibody Enbrel significantly reduces BV6/MS275-induced cell death in the majority of AML cell lines, indicating that autocrine/paracrine TNF alpha signaling contributes to cell death. Remarkably, the broad-range caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) fails to rescue MV4-11, Molm13 and OCI-AML3 cells and even enhances BV6/MS275-mediated cell death, whereas zVAD.fmk reduces BV6/MS275-induced cell death in NB4 cells. Annexin-V/propidium iodide (PI) double staining reveals that BV6/MS275 cotreatment predominately increases the percentage of double-positive cells. Of note, the Receptor-Interacting Protein (RIP)1 inhibitor necrostatin-1 (Nec-1) or the Mixed Lineage Kinase Domain-Like protein (MLKL) inhibitor necrosulfonamide (NSA) significantly reduce BV6/MS275-induced cell death in the presence of zVAD.fmk, suggesting that BV6/MS275 cotreatment triggers necroptosis when caspases are inhibited. Thus, BV6 acts in concert with HDACIs to induce cell death in AML cells and can bypass apoptosis resistance, at least in several AML cell lines, by engaging necroptosis as an alternative route of regulated cell death. The identification of a novel synergism of BV6 and HDACIs has important implications for the development of new treatment strategies for AML. (C) 2015 Elsevier Ireland Ltd. All rights reserved.