Molecular mechanisms of discrotophos-induced toxicity in HepG2 cells: The role of CSA in oxidative stress

• Published in: Food and chemical toxicology Vol. 103; pp. 253 - 260
• Main Authors: Hseu, You-Cheng, Hsu, Tung-Wei, Lin, Heng-Dao, Chen, Chin Hui, Chen, Ssu Ching
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2017
• Subjects: Apoptosis; Apoptosis - drug effects; Autophagy; Autophagy - drug effects; Cell Cycle Checkpoints - drug effects; CSA; Dicrotophos; DNA Damage - drug effects; DNA Repair - drug effects; DNA Repair - genetics; DNA Repair Enzymes - genetics; DNA Repair Enzymes - metabolism; Gene Expression Regulation - drug effects; Hep G2 Cells - drug effects; Hep G2 Cells - pathology; Humans; Membrane Potential, Mitochondrial - drug effects; Organophosphorus Compounds - toxicity; Oxidative Stress - drug effects; Oxidative Stress - physiology; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA-seq; ROS; Sequence Analysis, RNA; Transcription Factors - genetics; Transcription Factors - metabolism; Dicrotophos; CSA; RNA-seq; Autophagy; ROS; Apoptosis
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2017.03.023

Dicrotophos (Dic), an insecticide and acaricide, is used against a variety of sucking, boring and chewing pests. It was proven that Dic induced oxidative DNA damage in HepG2 cells. However, the molecular mechanisms of this compound were still unclear. First of all, the cytotoxicity and oxidative DNA damage were confirmed. Next, using RNA-seq for detecting differential expressed genes (DEGs) in cells treated with 50 μM Dic for 24 h, we showed that the dysregulation of these genes, irrespective of up (1298 genes) or down (2125 genes) regulation, could be attributed to some diverse pathways/metabolisms using KEGG analysis, particularly in DNA damage responses (DDRs) such as oxidative phosphorylation, nucleotide excision repair and cell cycle arrest. Validation of some randomly selected DDR genes confirmed RNA-seq results. We further demonstrated that Dic induced ROS overproduction, the loss of mitochondrial depolarization and cell cycle arrest in the G0/G1 phase. In addition, we also definitely clarified the role of CSA, a nucleotide excision repair enzymes in Dic-treated cells. Collectively, our results showed that various mechanisms of Dic-induced toxicity in HepG2 cells including downregulation of some genes related to nucleotide excision repair including CSA and increased oxidative stress. •Dicrotophos (Dic) induced oxidative DNA damage and the loss of mitochondrial membrane potential in HepG2 cells.•RNA-seq analysis confirmed the change of transcriptome response invoked by Dic.•The role of CSA, a nucleotide excision repair enzymes, in oxidative DNA damage was confirmed.•A proposed model suggested for the molecular toxicity of Dic in HepG2 cells.