Experimental conditions to study cytotoxic effects of arsenic in CHO cells

BONGIOVANNI GA; SORIA EA; EYNARD AR

Villa General Belgrano (Argentina)

Jornada; XIV Jornadas Científicas de la Sociedad de Biología de Córdoba; 2003

In the south-eastern region of the Province of Cordoba, elevated arsenic levels are in drinking water averaged 178 ppb. It was observed a dose-response relation between ingestion of arsenic from drinking water and HACRE ("hidroarsenicismo crónico regional endémico"), highly related to bladder, skin and lung cancers. In mammals, ar­senic induces stress response, cytoskeletal alterations and MAP Kinase activation. However, lack of an animal model has limited progress on the understanding of the mechanism of arsenic-linked carcinogenesis. Objective: To develop a model in cultured cell to study the molecular events, which may mimic arsenic carcinogen­esis. Cell culture: the non-tumoral cell line CHO-K1 was incubated through different times in DME medium containing 10% foetal bovine serum, with the addition of different amounts of sodium arsenite. Western blot and immunocytochemistry were used to de­termine the Hsp70 (heat shock protein 70 kDa) induction and to visualize the actin filaments, respectively. Cells grown for 1 ½ hours in the presence of the sodium 200 JJ.M arsenite followed by 3 hours of recovery, showed the Hsp70 induction. If the cells were cultured for 2 ½ hours in the presence of sodium arsenite (200 µM), they responded with striking changes in their cell shape and remodelling of the actin filament network since actin acquires perinuclear localization. We observed that CHO cells will undergo stress response after acute arsenic exposure and that this response is associated with expression of Hsp, morphologic changes and cytoskeletal al­terations. So, 200 µM Sodium arsenite and 2 ½ hours will be useful conditions to future experiments.