Mechanistic characterization of tenuazonic acid-induced cellular stress responses in human esophageal KYSE-510 cells

Abstract

Tenuazonic acid (TeA) is an emerging Alternaria mycotoxin frequently detected in food and feed commodities, raising concerns about its toxicological relevance. Chronic oral exposure to TeA has been reported to induce dysplastic alterations in the esophageal mucosa of mice, while human biomonitoring data indicate an association between TeA exposure and esophageal cancer, although a causal relationship has not yet been established. At a mechanistic level, the effects of TeA in esophageal cells remain poorly characterized. Therefore, this study investigated the impact of TeA on cytotoxicity, oxidative stress, DNA damage, mitochondrial homeostasis, cell-cycle distribution and transcriptomic stress responses in human esophageal KYSE-510 cells. TeA induced a concentration-dependent reduction in metabolic activity and total protein content after 24 h exposure to 0.1-100 {micro}M. Significant cytotoxicity was measured starting from 20 {micro}M. At sub-cytotoxic concentrations, TeA triggered rapid ROS formation within 5-30 min exposure and induced formamidopyrimidine-DNA glycosylase (FPG) sensitive DNA damage after 1 h exposure (5-7.5 {micro}M), indicating oxidative DNA lesions. In addition, TeA altered mitochondrial morphology after 4 h exposure at 7.5 {micro}M, manifested by shrinkage of the mitochondrial network area and perinuclear redistribution, while mitochondrial respiration showed only a non-significant tendency towards reduced respiratory capacity. RNA sequencing after 6 h exposure to 10 {micro}M TeA revealed oxidative stress-associated transcriptional changes, impaired antioxidant and stress-adaptive responses, and p53-associated stress signaling. Furthermore, TeA induced significant G2/M phase accumulation after 24 h exposure to 1-10 {micro}M. HighlightsO_LITeA triggers rapid oxidative stress in human esophageal KYSE-510 cells C_LIO_LISub-cytotoxic TeA induces FPG-sensitive oxidative DNA lesions C_LIO_LITeA disrupts mitochondrial morphology before overt cytotoxicity occurs C_LIO_LIRNA-seq reveals impaired antioxidant defense and p53-linked stress signaling C_LIO_LITeA promotes G2/M phase accumulation and concentration-dependent cytotoxicity C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/736731v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@a496faorg.highwire.dtl.DTLVardef@1b42072org.highwire.dtl.DTLVardef@be5088org.highwire.dtl.DTLVardef@991b5b_HPS_FORMAT_FIGEXP M_FIG C_FIG