Müller T, Gebel S
INBIFO Institut für biologische Forschung, Köln, Germany.
Carcinogenesis. 1998 May;19(5):797-801. doi: 10.1093/carcin/19.5.797.
Mainstream cigarette smoke (CS) trapped in phosphate-buffered saline solutions (smoke-bubbled PBS) has been shown to induce a strong stress response in cultured cells. This is reflected, for example, by the expression of stress genes such as c-fos and haem oxygenase, a transient decrease in the translation efficiency and the induction of cell cycle arrest. In these studies, peroxynitrite, the reaction product of nitric oxide (NO) and superoxide (O2-.), was identified as an active principle formed by CS in aqueous solutions. In the present study, we show that the CS-induced stress response is critically dependent on the intracellular glutathione (GSH) content which itself becomes diminished in cells exposed to smoke-bubbled PBS. Investigations using c-fos expression as a measure for cellular stress revealed a direct correlation between the smoke-bubbled PBS concentration necessary for stress-dependent c-fos expression and the intracellular GSH concentration observed in different cell lines. Correspondingly, 3T3 fibroblasts artificially depleted of GSH by pretreatment with buthionine-sulphoximine (BSO), an inhibitor of GSH synthesis, require significantly lower amounts of smoke-bubbled PBS to obtain a detectable c-fos expression, whereas, supplementation of the medium with N-acetyl-cysteine is an efficient treatment for the inhibition of a CS-induced c-fos response. We also show that the smoke-bubbled PBS-dependent loss of intracellular GSH is mainly attributable to the aldehyde fraction of CS, although these aldehydes by themselves cannot induce c-fos in these cells. The smoke-bubbled PBS-dependent c-fos response can, however, be mimicked when peroxynitrite and CS-related aldehydes, at the concentrations calculated to appear in smoke-bubbled PBS, are used in combination for cell exposure. Taken together, these results suggest that in cells exposed to aqueous extracts of CS, smoke-related aldehydes decrease the intracellular GSH content significantly, allowing peroxynitrite to interfere with specific target molecules resulting in the stress-specific expression of c-fos.
困于磷酸盐缓冲盐溶液（烟熏 PBS）中的主流香烟烟雾（CS）已被证明可在培养细胞中诱导强烈的应激反应。例如，这表现为应激基因如 c-fos 和血红素加氧酶的表达、翻译效率的短暂降低以及细胞周期停滞的诱导。在这些研究中，过氧亚硝酸盐，即一氧化氮（NO）和超氧化物（O2-.）的反应产物，被确定为 CS 在水溶液中形成的一种活性成分。在本研究中，我们表明 CS 诱导的应激反应关键取决于细胞内谷胱甘肽（GSH）的含量，而在暴露于烟熏 PBS 的细胞中，GSH 自身含量会减少。以 c-fos 表达作为细胞应激指标的研究表明，应激依赖性 c-fos 表达所需的烟熏 PBS 浓度与在不同细胞系中观察到的细胞内 GSH 浓度之间存在直接相关性。相应地，用谷胱甘肽合成抑制剂丁硫氨酸 - 亚砜胺（BSO）预处理使 GSH 人工耗竭的 3T3 成纤维细胞，需要显著更低量的烟熏 PBS 才能获得可检测到的 c-fos 表达，而向培养基中补充 N-乙酰半胱氨酸是抑制 CS 诱导的 c-fos反应的有效处理方法。我们还表明，烟熏 PBS 依赖性细胞内 GSH 的损失主要归因于 CS 的醛类成分，尽管这些醛类本身不能在这些细胞中诱导 c-fos。然而，当过氧亚硝酸盐和 CS 相关醛类以计算出在烟熏 PBS 中出现的浓度联合用于细胞暴露时，可模拟烟熏 PBS 依赖性 c-fos 反应。综上所述，这些结果表明，在暴露于 CS水提取物的细胞中，与烟雾相关的醛类会显著降低细胞内 GSH 含量，使过氧亚硝酸盐能够干扰特定靶分子，从而导致 c-fos 的应激特异性表达。
