Suppression of sphingomyelin synthase 1 by small interference RNA is associated with enhanced ceramide production and apoptosis after photodamage
Suppression of sphingomyelin synthase 1 by small interference RNA is associated with enhanced ceramide production and apoptosis after photodamage
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DOI：
10.1016/j.yexcr.2008.02.008
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发表时间：
2008-05-01
影响因子：
3.7
通讯作者：
Luberto, Chiara
中科院分区：
文献类型：
--
作者：
Separovic, Duska;Semaan, Louie;Luberto, Chiara
我们已经证明，SMS1（一种将神经酰胺从头转化为鞘磷脂的酶）的过度表达伴随着光敏剂 Pc 4（光动力疗法；PDT）光损伤后神经酰胺反应的减弱和细胞凋亡抵抗。为了测试 PDT 后 SMS1 过度表达相关的影响是否可以逆转，在本研究中，使用 SMS1 的小抑制性 RNA (siRNA) 在 Jurkat T 淋巴瘤/白血病细胞中下调 SMS1。与乱序（对照）siRNA 转染子相比，在 SMS1 siRNA 转染细胞中，静息状态下的 SMS 活性下调，同时鞘磷脂质量减少。在 PDT 后，SMS1 siRNA 转染细胞中神经酰胺的增加高于对照 siRNA 转染细胞。二氢神经酰胺也获得了类似的结果，表明涉及从头神经酰胺途径。与对照细胞相比，SMS1 siRNA 转染细胞中 PDT 诱导的 DEVDase（半胱天冬酶 3 样）激活增强。数据显示，RNA 干扰依赖性 SMS1 下调与神经酰胺和二氢神经酰胺积累增加有关，同时伴随着光损伤后细胞对细胞凋亡的敏感性。类似地，在 SMS2 siRNA 转染的细胞中，SMS 活性的下调伴随着光损伤后 DEVDase 激活的增强。这些发现表明 SMS 是一个潜在的新型分子靶点，可以增强 PDT 的治疗效果。 (C) 2008 Elsevier Inc. 保留所有权利。
We have shown that overexpression of SMS1, an enzyme that converts de novo ceramide into sphingomyelin, is accompanied by attenuated ceramide response and apoptotic resistance after photodamage with the photosensitizer Pc 4 (photodynamic therapy; PDT). To test whether SMS1 overexpression-related effects after PDT can be reversed, in this study SMS1 was downregulated in Jurkat T lymphoma/leukemia cells using small inhibitory RNA (siRNA) for SMS1. Compared to scrambled (control) siRNA-transfectants, in SMS1 siRNA-transfected cells the activity of SMS at rest was downregulated with concomitant decrease in sphingomyelin mass. In SMS1 siRNA-transfected cells increases in ceramides were higher than in control siRNA-transfectants after PDT. Similar findings were obtained for dihydroceramides suggesting the involvement of de novo ceramide pathway. PDT-induced DEVDase (caspase-3-like) activation was enhanced in SMS1 siRNA-transfected cells compared to their control counterparts. The data show that RNA interference-dependent downregulation of SMS1 is associated with increased accumulation of ceramide and dihydroceramide with concomitant sensitization of cells to apoptosis after photodamage. Similarly, in SMS2 siRNA-transfected cells, downregulation of SMS activity was accompanied by potentiated DEVDase activation post-photodamage. These findings suggest that SMS is a potential novel molecular target that can augment therapeutic efficacy of PDT. (C) 2008 Elsevier Inc. All rights reserved.