Poulaki Vassiliki, Mitsiades Constantine S, Kotoula Vassiliki, Tseleni-Balafouta Sophia, Ashkenazi Avi, Koutras Demetrios A, Mitsiades Nicholas
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114, USA.
Am J Pathol. 2002 Aug;161(2):643-54. doi: 10.1016/S0002-9440(10)64220-4.
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)/Apo2 ligand selectively kills neoplastic cells, including thyroid carcinoma cells (Mitsiades et al: Thyroid carcinoma cells are resistant to FAS-mediated apoptosis but sensitive to tumor necrosis factor-related apoptosis-inducing ligand. Cancer Res 2000, 60:4122-41299). We investigated the mechanisms regulating Apo2L/TRAIL-induced apoptosis in thyroid carcinoma cells, as well as the impact of insulin-like growth factor (IGF)-1, interferon-gamma, and TNF-alpha. We found that the emergence of resistance to Apo2L/TRAIL, after prolonged incubation with this cytokine, was associated with increased levels of FLICE inhibitory protein (FLIP), and was overcome by cycloheximide and bisindolylmaleimide, that specifically down-regulated FLIP expression, as well as by transfection of a FLIP anti-sense oligonucleotide. IGF-1 activated Akt; up-regulated the caspase inhibitors FLIP, cIAP-2, XIAP, and survivin; and attenuated Apo2L/TRAIL-induced apoptosis. This effect was inhibited by the IGF-1 receptor neutralizing antibody aIR3, the PI-3K inhibitor wortmannin, and the heat shock protein-90 chaperone inhibitor geldanamycin. Transfection of constitutively active Akt protected from TRAIL. Conversely, interferon-gamma and TNF-alpha had a sensitizing effect. We conclude that FLIP may negatively regulate Apo2L/TRAIL-induced apoptosis in thyroid carcinomas. Microenvironmental paracrine survival factors, such as IGF-1, up-regulate caspase inhibitors, including FLIP, and protect from Apo2L/TRAIL in a PI-3K/Akt-dependent manner. T helper-1 cytokines and compounds that selectively abrogate the IGF-1 signaling pathway may be helpful adjunct agents in Apo2L/TRAIL-based anti-cancer therapeutic regimens.
肿瘤坏死因子（TNF）相关凋亡诱导配体（TRAIL）/Apo2配体可选择性杀伤肿瘤细胞，包括甲状腺癌细胞（米齐亚德斯等人：甲状腺癌细胞对FAS介导的凋亡具有抗性，但对肿瘤坏死因子相关凋亡诱导配体敏感。《癌症研究》2000年，60:4122 - 41299）。我们研究了调节Apo2L/TRAIL诱导甲状腺癌细胞凋亡的机制，以及胰岛素样生长因子（IGF）-1、干扰素-γ和TNF-α的影响。我们发现，在与这种细胞因子长时间孵育后，对Apo2L/TRAIL产生抗性与FLICE抑制蛋白（FLIP）水平升高有关，而放线菌酮和双吲哚马来酰胺可克服这种抗性，它们能特异性下调FLIP表达，转染FLIP反义寡核苷酸也可克服。IGF-1激活Akt；上调半胱天冬酶抑制剂FLIP、cIAP-2、XIAP和生存素；并减弱Apo2L/TRAIL诱导的凋亡。IGF-1受体中和抗体aIR3、PI-3K抑制剂渥曼青霉素和热休克蛋白-90伴侣抑制剂格尔德霉素可抑制这种作用。组成型活性Akt的转染可保护细胞免受TRAIL作用。相反，干扰素-γ和TNF-α具有致敏作用。我们得出结论，FLIP可能对Apo2L/TRAIL诱导的甲状腺癌凋亡起负调节作用。微环境旁分泌生存因子，如IGF-1，上调包括FLIP在内的半胱天冬酶抑制剂，并以PI-3K/Akt依赖的方式保护细胞免受Apo2L/TRAIL作用。辅助性T细胞1细胞因子和选择性消除IGF-1信号通路的化合物可能是基于Apo2L/TRAIL的抗癌治疗方案中有帮助的辅助药物。
