cytotoxic activities of silver nanoparticles and silver ions in parent and tamoxifen-resistant t47d human breast cancer cells and their combination effects with tamoxifen against resistant cells

studies on biomedical applications of nanoparticles are growing with a rapid pace. in medicine, nanoparticles may be the solution for multi-drug-resistance which is still a major drawback in chemotherapy of cancer. in the present study, we investigated the potential cytotoxic effect of silver nanoparticles (ag nps) and silver ions (ag+) in both parent and tamoxifen-resistant t47d cells in presence and absence of tamoxifen. ag nps were synthesized (< 28 nm) and mtt assay was carried out. the associated ic50 values were found to be: 6.31 ?g/ml for ag nps/parent cells, 37.06 ?g/ml for ag nps/tamoxifen-resistant cells, 33.06 ?g/ml for ag+/parent cells and 10.10 ?g/ml for ag+/resistant cells. as a separate experiment, the effect of subinhibitory concentrations of ag nps and ag+ on the proliferation of tamoxifen resistant cells was evaluated at non-toxic concentrations of tamoxifen. our results suggested that in non-cytotoxic concentrations of silver nanomaterials and tamoxifen, the combinations of ag+-tamoxifen and ag nps-tamoxifen are still cytotoxic. this finding may be of great potential benefit in chemotherapy of breast cancer; since much lower doses of tamoxifen may be needed to produce the same cytotoxic effect and side effects will be reduced.