Cytotoxic effects induced by combined exposure to the mycotoxins sterigmatocystin, ochratoxin A and patulin on human tumour and healthy 3D spheroids

Humans are exposed to complex mixtures of mycotoxins through diet. Despite the serious threat they pose, mycotoxin risk assessment often overlooks co-exposure. With the aim of filling this gap, the present study investigates the combined cytotoxicity of sterigmatocystin (STE), ochratoxin A (OTA) and patulin (PAT) in human tumour Neuroblastoma and healthy Mesenchymal Stem Cells three-dimensional (3D) spheroids. The range of concentrations tested (1.56–50 μM for STE, 0.78–25 μM for OTA and 0.15–5 μM for PAT) was selected considering the IC 50 values obtained in previous studies and the estimated dietary exposure of consumers. To ensure appropriate experimental conditions, assessments for single mycotoxins and their combinations were conducted simultaneously. The nature of the toxicological interactions among the mycotoxins was then defined using the isobologram analysis. Our results demonstrated increased cytotoxicity in mycotoxin mixtures compared to individual exposure, with abundance of synergistic interactions. These findings highlight that the co-occurrence of STE, OTA and PAT in food may increase their individual toxic effects and should not be underestimated. Moreover, the use of advanced culture models increased the reliability and physiological relevance of our results which can serve as a groundwork for formulating standardized regulatory approaches towards mycotoxin mixtures in food and feed. • To assess the cytotoxicity associated with the co-exposure to STE, OTA and PAT. • To facilitate a deeper understanding, advanced culture models (spheroids) were used. • The nature of toxicological interactions was defined by isobologram analysis. • In BM-MSCs spheroids, single mycotoxin effects were enhanced by combined exposure. • In SH-SY5Y spheroids, mainly additive/synergistic interactions were revealed.