Comparative Cytotoxicity,Oxidative Stress,and Cytokine Secretion Induced by Two Cyanotoxin Variants,Microcystin LR and RR,in Human Intestinal Caco‐2 Cells

While MC‐LR and MC‐RR share significant structural similarity, MC‐RR is less cytotoxic than MC‐LR. In the current study, we have compared the effects of MC‐LR and MC‐RR in Caco‐2 cells by evaluating cytotoxicity, oxidative stress (reactive oxygen species production), and the cellular proinflammatory response (IL‐6 and IL‐8 production). Following treatment with 100 µM microcystins (MC), cytotoxicity was two‐fold greater with MC‐LR as compared to MC‐RR after 24 h exposure. Whereas the reactive oxygen species production and IL‐6 secretion were similar following a 24‐h treatment with either MC, 100 µM MC‐LR induced a five‐fold greater IL‐8 secretion when compared to MC‐RR. Our study has demonstrated that, although both MC‐LR and MC‐RR induced some cytotoxicity in human intestinal cells, a major difference in IL‐8 production was observed between the two variants. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:253‐258, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21482