Sulforaphane induces glutathione S-transferase alpha in subconfluent CaCo-2 colon cancer cells

The human CaCo-2 cell line, which originates from colon adenocarcinoma kept the ability to differentiate at confluence, thus acquiring an intestinal c ell phenotype. Thus this model allows to examine both proliferative and dif ferentiated cancer cells. In this work, we have tested a natural isothiocya nate, sulforaphane, which displays protective effects against carcinogenesi s. Its toxicity is confirmed towards proliferating colon cancer cells. In a ddition, sulforaphane shows to specifically induce alpha -class glutathione S-transferases in these cells. Unlike confluent cells, which strongly expr ess GST alpha and were found resistant to sulforaphane toxicity, subconflue nt cells expressing this enzyme were still sensitive to this compound. We s uggest GST alpha may possibly be related to growth arrest. (C) 2001 Elsevie r Science Ireland Ltd. All rights reserved.