The cytotoxic effects of cadmium chloride on the human lung carcinoma (Calu-6) cell line

Cadmium has been known to be harmful to human health, mainly via contaminated drinking water, food supplies, tobacco and industrial pollutants. The aim of this study was to determine the ability of cadmium chloride (CdCl2) to cause cell death in the human lung carcinoma cell line (Calu-6). The cells were grown in RPMI-1640 medium supplemented with 10% FCS, penicillin/streptomycin (100 U/ml, 100 µg/ml) at 37 ºC in 5% CO2/95% air. The cells were plated in 96 multi-well plates. After 24 h, the medium was replaced with fresh medium containing different concentrations of CdCl2 and incubated for 48 and 72 h. MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) cell viability test was used to study the cytotoxic effects of Cd. Exposure of monolayers to different metal concentrations (1-1000 µM) in different times showed a significant decrease (P<0.05) in cell viability when compared with that of controls. In a dose-dependent manner, a significant cytotoxicity was observed at 200 µM for CdCl2 during 48 h and 1 µM during 72 h exposure. However the concentrations greater than 200 μM had no significant effect to accelerate the power of cytotoxicity. Thus, CdCl2 has this ability to induce cytotoxicity in the human lung carcinoma cell line in the lower micromolar concentrations. In conclusion, while high concentrations of Cd are harmful to human, lower concentrations induce a significant cytotoxicity in the cancer cells. This finding may introduce a new view on the mode of action and possible application of trace elements in the cancer treatment.