Comparative study of cyanotoxins affecting cytoskeletal and chromatin structures in CHO-K1 cells.
In this study we compared the effects of the two frequently occuring and most dangerous cyanobacterial toxins on the cellular organization of microfilaments, microtubules and on the chromatin structure in Chinese hamster ovary (CHO-K1) cells. These compounds are the widely known microcystin-LR (MC-LR) and cylindrospermopsin (CYN) classified as the highest-priority cyanotoxin. Toxic effects were tested in a concentration and time dependent manner. The hepatotoxic MC-LR did not cause significant cytotoxicity on CHO-K1 cells under 20 microM, but caused apoptotic changes at higher concentrations. Apoptotic shrinkage was associated with the shortening and loss of actin filaments and with a concentration dependent depolymerization of microtubules. No necrosis was observed over the concentration range (1-50 microM MC-LR) tested. Cylindrospermopsin did cause apoptosis at low concentrations (1-2 microM) and over short exposure periods (12h). Necrosis was observed at higher concentrations (5-10 microM) and following longer exposure periods (24 or 48h). Cyanotoxins also affected the chromatin structure. The condensation process was inhibited by MC-LR at a later stage and manifested as broken elongated prechromosomes. CYN inhibited chromatin condensation at the early fibrillary stage leading to blurred fluorescent images of apoptotic bodies and preventing the formation of metaphase chromosomes. Cylindrospermopsin exhibited a more pronounced toxic effect causing cytoskeletal and nuclear changes as well as apoptotic and necrotic alterations.
Gácsi
Mariann
M
Department of Experimental Zoology, Balaton Limnological Research Institute, Hungarian Academy of Sciences, Tihany, Hungary.
Antal
Otilia
O
Vasas
Gábor
G
Máthé
Csaba
C
Borbély
György
G
Saker
Martin L
ML
Gyori
János
J
Farkas
Anna
A
Vehovszky
Agnes
A
Bánfalvi
Gáspár
G
D000470:Alkaloids; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001427:Bacterial Toxins; D002470:Cell Survival / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects*; D006224:Cricetinae; D000087522:Cyanobacteria Toxins; D003599:Cytoskeleton / Q000737:chemistry / Q000187:drug effects*; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D014498:Uracil / Q000031:analogs & derivatives* / Q000633:toxicity
D000470:Alkaloids; D001427:Bacterial Toxins; D002843:Chromatin; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; C089595:cylindrospermopsin; D014498:Uracil; C057862:cyanoginosin LR