Synergistic cytotoxicity of deoxynivalenol and nivalenol at realistic dietary exposure ratios through ribotoxic stress-induced apoptosis in Caco-2 cells

Abstract

Trichothecenes, deoxynivalenol (DON) and nivalenol (NIV), frequently co-contaminate food, posing potential health risks through their combined toxicity effects. While previous studies have assessed DON-NIV interactions using arbitrary or effective concentration-based ratios, this study investigated their effects using realistic dietary exposure ratios estimated from South Korean food consumption data. Undifferentiated and differentiated Caco-2 cells were treated with DON and NIV, individually or in combination. Cell viability, combination index (CI), mitogen-activated protein kinase (MAPK) and apoptosis-related gene and protein expression, total protein content, and apoptosis rates were assessed to evaluate cytotoxicity and underlying mechanisms. Co-treatment resulted in a greater reduction in cell viability than individual treatments in both undifferentiated and differentiated cell models. The CI analysis revealed synergistic effects across most fractions, affecting the values. Co-exposure upregulated MAPK and apoptosis-related pathways, reduced total protein content, and increased apoptosis rates compared with individual treatments. These findings suggest that the synergistic toxicity of DON and NIV may be mediated through ribotoxic stress response, MAPK activation, and apoptosis. Given the frequent co-occurrence of DON and NIV in food, these results emphasize the importance of realistic co-exposure-based assessments and continuous monitoring to ensure food safety and mitigate human health risks.

Keywords: Apoptosis; Combined effect; Deoxynivalenol; Mitogen-activated protein kinase; Nivalenol; Ribotoxic stress response.