E171-induced toxicity in human iPSC-derived colon organoids: Effects on cell viability, ROS generation, DNA damage, and gene expression changes

Food-grade titanium dioxide (E171) is a widely used food additive with debated safety, particularly regarding its genotoxic effects. This study assessed the dose-dependent toxicity of E171 in human induced pluripotent stem cell (iPSC)-derived colon organoids. Organoids were exposed to E171 (0.1–1000 μg/mL) for 24 h, and effects on cell viability, reactive oxygen species (ROS) generation, DNA damage, and gene expression were evaluated. Results showed no impact on cell viability but a dose-dependent increase in ROS formation, peaking at 1000 μg/mL. Electrospin Resonance Spectroscopy (ESR) showed a dose-dependent increase in ROS, with increased E171 concentrations. The alkaline comet assay revealed significant DNA damage from 100 μg/mL, with oxidative DNA damage detected at 10 μg/mL using formamidopyrimidine DNA glycosylase (FPG). RNA sequencing identified differentially expressed genes (DEGs) at 100 and 250 μg/mL, linked to translational activity, signal transduction, and DNA damage repair. Gene set enrichment analysis (GSEA) indicated activation of ribosome, chemical carcinogenesis–ROS, and metabolic pathways (carbon metabolism, glycolysis), while key regulatory pathways (Wnt, MAPK, PI3K-Akt) were suppressed. These findings suggest that E171 induces oxidative stress and DNA damage, modulating transcriptomic pathways associated with metabolism, proliferation, and cancer. Further research is necessary to determine its long-term effects on human gastrointestinal health.