Arhoma A, Chantry A D, Haywood-Small S L, Cross N A
Biomolecular Sciences Research Centre, Sheffield Hallam University, United Kingdom.
Biomolecular Sciences Research Centre, Sheffield Hallam University, United Kingdom; Mellanby Centre for Bone Research, University of Sheffield, United Kingdom.
Exp Cell Res. 2017 Nov 15;360(2):226-235. doi: 10.1016/j.yexcr.2017.09.012. Epub 2017 Sep 8.
Multiple Myeloma (MM) is currently incurable despite many novel therapies. Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) is a potential anti-tumour agent although effects as a single agent are limited. In this study, we investigated whether the Histone Deacetylase (HDAC) inhibitor SAHA can enhance TRAIL-induced apoptosis and target TRAIL resistance in both suspension culture, and 3D cell culture as a model of disseminated MM lesions that form in bone.
The effects of SAHA and/or TRAIL in 6 Multiple Myeloma cell lines were assessed in both suspension cultures and in an Alginate-based 3D cell culture model. The effect of SAHA and/or TRAIL was assessed on apoptosis by assessment of nuclear morphology using Hoechst 33342/Propidium Iodide staining. Viable cell number was assessed by CellTiter-Glo luminescence assay, Caspase-8 and -9 activities were measured by Caspase-Glo™ assay kit. TRAIL-resistant cells were generated by culture of RPMI 8226 and NCI-H929 by acute exposure to TRAIL followed by selection of TRAIL-resistant cells.
TRAIL significantly induced apoptosis in a dose-dependent manner in OPM-2, RPMI 8226, NCI-H929, U266, JJN-3 MM cell lines and ADC-1 plasma cell leukaemia cells. SAHA amplified TRAIL responses in all lines except OPM-2, and enhanced TRAIL responses were both via Caspase-8 and -9. SAHA treatment induced growth inhibition that further increased in the combination treatment with TRAIL in MM cells. The co-treatment of TRAIL and SAHA reduced viable cell numbers all cell lines. TRAIL responses were further potentiated by SAHA in 3D cell culture in NCI-H929, RPMI 8226 and U266 at lower TRAIL + SAHA doses than in suspension culture. However TRAIL responses in cells that had been selected for TRAIL resistance were not further enhanced by SAHA treatment.
SAHA is a potent sensitizer of TRAIL responses in both TRAIL sensitive and resistant cell lines, in both suspension and 3D culture, however SAHA did not sensitise TRAIL-sensitive cell populations that had been selected for TRAIL-resistance from initially TRAIL-sensitive populations. SAHA may increase TRAIL sensitivity in insensitive cells, but not in cells that have specifically been selected for acquired TRAIL-resistance.
尽管有许多新型疗法，但多发性骨髓瘤（MM）目前仍无法治愈。肿瘤坏死因子相关凋亡诱导配体（TRAIL）是一种潜在的抗肿瘤药物，尽管其作为单一药物的效果有限。在本研究中，我们调查了组蛋白去乙酰化酶（HDAC）抑制剂SAHA是否能增强TRAIL诱导的凋亡，并在悬浮培养和3D细胞培养中作为骨中形成的播散性MM病变模型来靶向TRAIL耐药性。
在悬浮培养和基于藻酸盐的3D细胞培养模型中评估SAHA和/或TRAIL对6种多发性骨髓瘤细胞系的影响。通过使用Hoechst 33342/碘化丙啶染色评估核形态来评估SAHA和/或TRAIL对凋亡的影响。通过CellTiter-Glo发光测定法评估活细胞数量，通过Caspase-Glo™测定试剂盒测量Caspase-8和-9活性。通过急性暴露于TRAIL然后选择TRAIL耐药细胞来培养RPMI 8226和NCI-H929以产生TRAIL耐药细胞。
TRAIL在OPM-2、RPMI 8226、NCI-H929、U266、JJN-3 MM细胞系和ADC-1浆细胞白血病细胞中以剂量依赖性方式显著诱导凋亡。SAHA在除OPM-2之外的所有细胞系中增强了TRAIL反应，并且增强的TRAIL反应均通过Caspase-8和-9。SAHA处理诱导生长抑制，在与TRAIL联合处理的MM细胞中进一步增加。TRAIL和SAHA的联合处理降低了所有细胞系的活细胞数量。在NCI-H929、RPMI 8226和U266的3D细胞培养中，与悬浮培养相比，在较低的TRAIL + SAHA剂量下，SAHA进一步增强了TRAIL反应。然而，SAHA处理并未进一步增强已选择TRAIL耐药性的细胞中的TRAIL反应。
SAHA在悬浮培养和3D培养中对TRAIL敏感和耐药细胞系都是TRAIL反应的有效敏化剂，然而SAHA对从最初TRAIL敏感群体中选择的TRAIL敏感细胞群体不具有敏化作用。SAHA可能会增加不敏感细胞对TRAIL的敏感性，但不会增加专门选择获得TRAIL耐药性的细胞对TRAIL的敏感性。
