MODULATION OF ORGANOTIN-INDUCED APOPTOSIS BY THE WATER POLLUTANT METHYL MERCURY IN A HUMAN LYMPHOBLASTOID TUMOR-CELL LINE AND A MARINE SPONGE

Apoptosis is a special form of cell death in which the cells actively participate in the process of dying. We found that the water pollutants tributyltin (> 1 muM) and methyl mercury (MeHg; at concentrations of > 3 muM) induce apoptosis in human T-lymphoblastoid CEM cells and in tissue of the marine sponge Geodia cydonium. At concentrations of > 5 muM, MeHg causes alkaline-labile sites in DNA of CEM cells. At the lower dose of 0.3 muM, MeHg abolishes the tributyltin-induced apoptosis in both CEM cells and sponge tissue. Incubation of sponge tissue with 3 muM of tributyltin induces not only apoptosis but also an increased expression of heat shock protein-70.