Global Gene Expression Analysis Reveals Differences in Cellular Responses to Hydroxyl- and Superoxide Anion Radical-...

Global Gene Expression Analysis Reveals Differences in Cellular Responses to Hydroxyl- and Superoxide-induced Oxidative Stress in Caco-2 Cells. Reactive oxygen species-induced oxidative stress in the colon is involved in inflammatory bowel diseases and is suggested to be associated with colorectal cancer risk. However, our insight in molecular responses to different oxygen radicals is still fragmentary. Therefore, we studied global gene expression by an extensive time serie (0.08, 0.25, 0.5, 1, 2, 4, 8, 16, or 24 hours ) analyses in human colon cancer (Caco-2) cells after exposure to H2O2 or menadione, leading to the formation of HO. or O2.- radicals respectively. Next to gene expression, induction of pathways and correlations with related phenotypic markers (oxidative DNA damage, cell cycle arrest) was investigated. Gene expression analysis resulted in 1404 differentially expressed genes upon H2O2 challenge and 979 genes after menadione treatment. Time-dependent co-regulated genes immediately showed a pulse-like response to HO. formation while the O2.--induced expression is not restored over 24 hours. Pathway analyses demonstrated that the difference in the modulation of gene expression is also reflected in regulation of pathways by HO. and O2.-: H2O2 immediately influences pathways involved in the immune function, while menadione constantly regulated cell cycle-related pathways. Altogether, this study offers a novel and detailed insight in differential time-dependent oxidative stress response, but most importantly, shows that effects of HO. and O2.- can also be discriminated regarding their modulation of particular carcinogenesis-related mechanisms. Keywords: Comparison of genome-wide gene expression between different time points for H2O2 and menadione. The study investigated differential gene expression in Caco-2 cell line mRNA at 9 timepoints (t=0.08, 0.25, 0.5, 1, 2, 4, 8, 16, or 24h) within 24 hours of exposure to H2O2 or manadione . Two biological replicates per time point. One compound per array, hybridized against time-matched control. Dye-swap include for all biological replicates.