Toxicological insights into graphene family materials: Cytochrome P450 modulation and cellular stress in liver cells

Graphene family materials (GFM), including pristine graphene (GN), graphene oxide (GO), and nano-sized graphene oxide (nGO), are increasingly utilized across industrial, environmental, and biomedical domains. Despite their potential benefits, the hazardous effects of GFM, particularly on liver xenobiotic-metabolizing enzymes and cellular functions, are not fully understood. Cytochrome P450 (CYP) are enzymes conserved across species, which play a crucial role in the metabolism of xenobiotics, drugs, environmental pollutants, and endogenous compounds, are key to understanding the biotransformation and detoxification processes impacted by GFM. This study investigates the effects of GFMs on CYP enzymes (CYP1A2, CYP2D6, CYP3A4) in a recombinant CYP system and HepG2 liver cells, alongside an assessment of cellular stress responses. In HepG2 cells, GFMs induced oxidative stress, mitochondrial depolarization, and cytotoxicity, with GN causing the most pronounced effects. GO exhibited the strongest inhibition of CYP enzymatic activity, particularly CYP1A2, in a dose-dependent manner in a recombinant CYP system. None of the tested nanomaterials significantly altered CYP expression, except for nGO, where a slight increase in CYP3A4 protein expression was observed. These findings highlight the significant influence of GFM physicochemical properties on their hazardous potential, especially their ability to disrupt metabolic processes and induce cellular stress. This study emphasizes the critical need for evaluating the safety of GFM in light of their widespread application and potential environmental and human health implications.