Involvement of ABC transporters in the efflux and toxicity of MPA-COOH-CdTe quantum dots in human breast cancer SK-BR-3 cells.

This paper aimed to study the possible involvement of adenosine triphosphate-binding cassette (ABC) transporters in the detoxification of quantum dots (QDs) in human breast carcinoma (SK-BR-3) cells. The effects of QD sizes on such interactions were also evaluated. For this purpose, we used monodispersed MPA-COOH-CdTe QDs with different diameters (emission length at 560 and 625 nm, named as QD-560 and QD-625). Such QDs tended to accumulate in cells and cause significant toxicity. Using specific inhibitors of ABC transporters, the cellular accumulation and toxicity of QDs in SK-BR-3 cells were significantly affected. Moreover, treatment of QDs caused concentration- and time-dependent induction of ABC transporters. Furthermore, the induction effects of smaller QDs were found to be greater than larger ones at equivalent concentrations, suggesting a size-dependent recognition of substrates by ABC transporters. Overall, these results provided important support for the modulation of QDs toxicity by ABC transporters.