Cell cycle-related genes associate with sensitivity to hydrogen peroxide-induced toxicity

Abstract

Reactive oxygen species (ROS) such as hydrogen peroxide (H ₂O ₂) are well-described agents in physiology and pathology. Chronic inflammation causes incessant H ₂O ₂ generation associated with disease occurrences such as diabetes, autoimmunity, and cancer. In cancer, conditioning of the tumor microenvironment, e.g., hypoxia and ROS generation, has been associated with disease outcomes and therapeutic efficacy. Many reports have investigated the roles of the action of H ₂O ₂ across many cell lines and disease models. The genes predisposing tumor cell lines to H ₂O ₂-mediated demise are less deciphered, however. To this end, we performed in-house transcriptional profiling of 35 cell lines and simultaneously investigated each cell line's H ₂O ₂ inhibitory concentration (IC ₂₅) based on metabolic activity. More than 100-fold differences were observed between the most resistant and sensitive cell lines. Correlation and gene ontology pathway analysis identified a rigid association with genes intertwined in cell cycle progression and proliferation, as such functional categories dominated the top ten significant processes. The ten most substantially correlating genes (Spearman r > 0.70 or < -0.70) were validated using qPCR, showing complete congruency with microarray analysis findings. Western blotting confirmed the correlation of cell cycle-related proteins negatively correlating with H ₂O ₂ IC ₂₅. Top genes related to ROS production or antioxidant defense were only modest in correlation (Spearman r > 0.40 or < -0.40). In conclusion, our in-house transcriptomic correlation analysis revealed a set of cell cycle-associated genes associated with a priori resistance or sensitivity to H ₂O ₂-induced cellular demise with the detailed and causative roles of individual genes remaining unclear.