Effects of reactive oxygen species on proliferation of Chinese hamster lung fibroblast (V79) cells

Abstract

Reactive oxygen species (ROS) have emerged as important signaling molecules in the regulation of various cellular processes. In our study, we investigated the effect of a wide range of ROS on Chinese hamster lung fibroblast (V79) cell proliferation. Treatment with $H_2O_2$, superoxide anion (generated by xanthine and xanthine oxidase), menadione and phenazine methosulfate increased the cell proliferation by approximately 50%. Moreover, a similar result was observed after partial inhibition of superoxide dismutase (SOD) and glutathione peroxidase. This up-regulation of cell proliferation was suppressed by pre-treatment with hydroxyl radical scavengers and iron chelating agents. In addition to ROS, treatment with exogenous catalase and SOD mimic (MnTMPyP) suppressed the normal cell proliferation. Short-term exposure of the cells to 100 micro M $H_2O_2$ was sufficient to induce proliferation, which indicated that activation of the signaling pathway is important as an early event. Accordingly, we assessed the ability of $H_2O_2$ to activate mitogen-activated protein kinases (MAPK). Jun-N-terminal kinase (JNK) and p38 MAPK were both rapidly and transiently activated by 100 μM H2O2, with maximal activation 30 minutes after treatment. The binding activity of AP-1 and the phosphorylation of c-Jun were also increased at the same time. However, the activity of extracellular signal-regulated kinase (ERK) was not changed. Pretreatment with SB203580 and SB202190, specific inhibitors of p38 MAPK, reduced the cell proliferation induced by $H_2O_2$. The activation of both JNK and p38 MAPK were also suppressed by pre-treatment with hydroxyl radical scavenger and iron chelating agent. These results suggest that the trace metal-driven Fenton reaction is a critical mechanism that underlies cell proliferation and MAPK activation. Further, the receptor tyrosine kinase, protein kinase C, and phospholipase $A_2$ pathways might be at least partially involved in the activation of JNK, p...