Effect of selenium compounds on murine B16 melanoma cells and pigmented cloned pB16 cells.

The effects of selenium compounds such as sodium selenite, sodium selenate, seleno-DL-cystine and seleno-DL-methionine (100 microM and 10 microM) on B16 and pigmented cloned pB16 murine melanoma cells were investigated in vitro. At the tested concentrations, B16 cells showed a greater sensitivity to the toxic effects of sodium selenite and seleno-DL-cystine than pB16 cells, whereas no decrease of B16 and pB16 cell number was observed after incubation with sodium selenate or seleno-DL-methionine. Glutathione (GSH) percentages were strongly decreased only by selenite and seleno-DL-cystine; it was marked more in B16 than in pB16 cells. The pretreatment of B16 cells with a GSH depleting agent (10 microM buthionine-[S,R]-sulfoximine) did not significantly influence the cytotoxic effects of selenite and seleno-DL-cystine. On both cell populations, GSH preincubation (50 microM) enhanced the cytotoxicity of selenite whereas the survival of seleno-DL-cystine treated cells was increased. Glutathione peroxidase (GSH-Px) activity in B16 cells was more sensitive than in pB16 cells to the activating effect of selenite, and particularly of seleno-DL-cystine: however, cell-free controls indicated that activation was mainly due to glutathione reductase. The rate of 75Se (as sodium selenite) uptake in both cell populations was maximal within the first hour of incubation, with a preferential accumulation in the cytosol; after 24 h of incubation, the amount of 75Se in cytosol and pellet was approximately the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of trace metals on mouse B16 melanoma cells in culture.

The effects of fourteen metal ions (As3+, As5+, Cd2+, Co2+, Cr3+, Cr6+, Hg2+, Li+, Mg2+, Mn2+, Ni2+, Se4+, V5+, VO2+) on the proliferation and differentiation in mouse B16 melanoma cells cultivated in vitro were analyzed. Cell number assays, melanin, and protein measurements, a 3(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide reduction test (MTT survival test), and a clonal growth assay were performed. At 10(-4)M, metal ions such as As3+, As5+, Cd2+, Cr6+, Se4+, V5+, VO2+, and, to a minor extent, Li+, Hg2+, and Co2+ significantly reduced the number of the B16 melanoma cells. For the same molar concentration, the order of the levels of cell toxicity of the metal compounds to B16 cells as measured by the MTT test was as follows: Hg2+ > Cr6+ = Cd2+ > As3+, As5+, > V5+, VO2+ > Se4+ = Ni2+ = Co2+ = Li+. An increased synthesis of melanin in B16 cells was noted after incubation with Co2+, Ni2+, Cd2+, and Li+, whereas Se4+ had, on the contrary, an inhibiting effect on melanogenesis.

Use of cell cultures, nuclear and radioanalytical techniques for metallotoxicological studies at the JRC-Ispra.

This paper reviews the JRC-Ispra research activity on toxicological studies related to the environmental and occupational exposure of trace metals, as carried out by a combination of cell culture methodologies with nuclear and radioanalytical techniques. Applications concern the setting of uptake-effect relationships and the study of the mechanisms of toxicity of specific metals (Al, As, Cd, Co, Cr, Mo, Se, V), as well as the establishment of ranking of metal toxicity by carrying out systematic studies (screening tests).

Use of cell cultures, nuclear and radioanalytical techniques for metallotoxicological studies at the JRC-Ispra.

This paper reviews the JRC-Ispra research activity on toxicological studies related to the environmental and occupational exposure of trace metals, as carried out by a combination of cell culture methodologies with nuclear and radioanalytical techniques.Applications concern the setting of uptake-effect relationships and the study of the mechanisms of toxicity of specific metals (Al, As, Cd, Co, Cr, Mo, Se, V), as well as the establishment of ranking of metal toxicity by carrying out systematic studies (screening tests).