Cytotoxic and mutagenic effects of ferric nitrilotriacetate on L5178Y mouse lymphoma cells.

An iron chelate, ferric nitrilotriacetate (Fe-NTA), induces renal proximal tubular necrosis that leads to a high incidence of renal adenocarcinoma in rodents. Others have shown that Fe-NTA induces modified DNA base products both in vitro and in vivo. However, Fe-NTA is negative in the Ames Salmonella test with or without S9 activation. The goal of this project was to determine if Fe-NTA is cytotoxic and mutagenic using the L5178Y (TK +/-) mouse lymphoma assay. Our experiments showed a relationship between the concentration of Fe-NTA (0 to 1 mM) and the decrease in relative survival. An exposure-dependent increase in the number of mutations was observed with increasing concentrations of Fe-NTA. At 14% relative survival, there was about a 4-fold increase in mutations (trifluorothymidine resistance) over unexposed, control cells. Ferric nitrate or nitrilotriacetic acid alone induced a relatively low 1.5- or 1.1-fold increase in mutation, respectively. Our results establish that Fe-NTA is mutagenic in the L5178Y mouse lymphoma assay system.