Mitochondrial superoxide anions induced by exogenous oxidative stress determine tumor cell fate: an individual cell-based study

AbstractObjectiveReactive oxygen species (ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli.MethodsModified microfluidics and imaging techniques were used to determine O2•− levels and construct an O2•− reaction network. To elucidate the consequences of increased O2•− input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca2+ levels, mitochondrial Ca2+ uptake, auto-amplification of intra-cellular ROS and the intrinsic apoptotic pathway.Results and conclusionsResults from a modified microchip demonstrated that 1 mmol/L H2O2 induced a rapid increase in cellular O2•− levels (>27 vs.>406 amol in 20 min), leading to increased cellular oxidizing power (evaluated by ROS levels) and decreased reducing power (evaluated by glutathione (GSH) levels). In addition, we examined the dynamics of cytosolic Ca2+ and mitochondrial Ca2+ by confocal laser scanning microscopy and confirmed that Ca2+ stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca2+ bursts. It is clear that mitochondria have pivotal roles in determining how exog...
Source: Journal of Zhejiang University. Science. B. - Category: Universities & Medical Training Source Type: research