Jc. Seegers et al., A COMPARATIVE-STUDY OF OCHRATOXIN A-INDUCED APOPTOSIS IN HAMSTER-KIDNEY AND HELA-CELLS, Toxicology and applied pharmacology, 129(1), 1994, pp. 1-11
Ochratoxin A (OA), produced by strains of Aspergillus and Penicillium,
at a dose of 20 mu g/ml caused nuclear and nucleolar changes characte
ristic of apoptosis in hamster kidney (HaK) and HeLa cells. However, t
he morphological and biochemical lesions were not identical in the two
cell types. In HaK cells micronuclei formation in prophase and interp
hase cells predominated but in HeLa cells apoptotic body formation was
more prevalent. Indirect immunofluorescence indicated that nucleolar
morphology was affected in both cell types with segregation of the fib
rillar and granular components of the nucleolus present after 24 hr ex
posure. [S-35]Methionine incorporation into SDS-PAGE-separated protein
s was decreased after continuous exposure for 24 hr, but after only 3
hr exposure, the synthesis of three proteins was markedly increased in
HaK (approximate to 39, 90, and 180 kDa) and HeLa (approximate to 40,
92, and 150 kDa) cells. Enhanced early synthesis of proteins was more
pronounced in HaK cells in the G(1)-phase and in HeLa cells in the S-
phase. Internucleosomal DNA breaks, characteristic of apoptosis, were
present in G(1) and S-phase HaK cells exposed to OA. In contrast, DNA
of very high molecular weight was seen in synchronized HeLa cells. The
results indicate that OA may activate different cellular processes in
volved in the degradation of DNA in HaK and HeLa cells. (C) 1994 Acade
mic Press, Inc.