Tazzari Pier Luigi, Tabellini Giovanna, Ricci Francesca, Papa Veronica, Bortul Roberta, Chiarini Francesca, Evangelisti Camilla, Martinelli Giovanni, Bontadini Andrea, Cocco Lucio, McCubrey James A, Martelli Alberto M
Servizio di Immunoematologia e Trasfusionale, Policlinico S. Orsola-Malpighi, Università di Bologna, Italy.
Cancer Res. 2008 Nov 15;68(22):9394-403. doi: 10.1158/0008-5472.CAN-08-2815.
To potentiate the response of acute myelogenous leukemia (AML) cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity, we have examined the efficacy of a combination with perifosine, a novel phosphatidylinositol-3-kinase (PI3K)/Akt signaling inhibitor. The rationale for using such a combination is that perifosine was recently described to increase TRAIL-R2 receptor expression and decrease the cellular FLICE-inhibitory protein (cFLIP) in human lung cancer cell lines. Perifosine and TRAIL both induced cell death by apoptosis in the THP-1 AML cell line, which is characterized by constitutive PI3K/Akt activation, but lacks functional p53. Perifosine, at concentrations below IC(50), dephosphorylated Akt and increased TRAIL-R2 levels, as shown by Western blot, reverse transcription-PCR, and flow cytometric analysis. Perifosine also decreased the long isoform of cFLIP (cFLIP-L) and the X-linked inhibitor of apoptosis protein (XIAP) expression. Perifosine and TRAIL synergized to activate caspase-8 and induce apoptosis, which was blocked by a caspase-8-selective inhibitor. Up-regulation of TRAIL-R2 expression was dependent on a protein kinase Calpha/c-Jun-NH(2)-kinase 2/c-Jun signaling pathway activated by perifosine through reactive oxygen species production. Perifosine also synergized with TRAIL in primary AML cells displaying constitutive activation of the Akt pathway by inducing apoptosis, Akt dephosphorylation, TRAIL-R2 up-regulation, cFLIP-L and XIAP down-regulation, and c-Jun phosphorylation. The combined treatment negatively affected the clonogenic activity of CD34(+) cells from patients with AML. In contrast, CD34(+) cells from healthy donors were resistant to perifosine and TRAIL treatment. Our findings suggest that the combination of perifosine and TRAIL might offer a novel therapeutic strategy for AML.
为增强急性髓性白血病（AML）细胞对肿瘤坏死因子相关凋亡诱导配体（TRAIL）细胞毒性的反应，我们研究了与哌立福新（一种新型磷脂酰肌醇-3-激酶（PI3K）/Akt信号抑制剂）联合使用的疗效。使用这种联合用药的理论依据是，最近有研究表明哌立福新可增加人肺癌细胞系中TRAIL-R2受体的表达并降低细胞FLICE抑制蛋白（cFLIP）的水平。哌立福新和TRAIL均可通过凋亡诱导THP-1 AML细胞系发生细胞死亡，该细胞系的特征是PI3K/Akt持续激活，但缺乏功能性p53。如蛋白质印迹、逆转录-PCR和流式细胞术分析所示，低于半数抑制浓度（IC50）的哌立福新可使Akt去磷酸化并提高TRAIL-R2水平。哌立福新还可降低cFLIP的长异构体（cFLIP-L）和X连锁凋亡抑制蛋白（XIAP）的表达。哌立福新和TRAIL协同激活半胱天冬酶-8并诱导凋亡，而这一过程被半胱天冬酶-8选择性抑制剂阻断。TRAIL-R2表达的上调依赖于哌立福新通过产生活性氧激活的蛋白激酶Cα/c-Jun氨基末端激酶2/c-Jun信号通路。哌立福新还可通过诱导凋亡、Akt去磷酸化、TRAIL-R2上调、cFLIP-L和XIAP下调以及c-Jun磷酸化，与TRAIL在原发性AML细胞中协同作用，这些原发性AML细胞表现出Akt途径的持续激活。联合治疗对AML患者的CD34(+)细胞的克隆形成活性产生负面影响。相比之下，健康供体的CD34(+)细胞对哌立福新和TRAIL治疗具有抗性。我们的研究结果表明，哌立福新和TRAIL联合使用可能为AML提供一种新的治疗策略。
