Selenium protection against mercury-induced apoptosis and growth inhibition in cultured K-562 cells

Selenium and mercuric chloride (MC) interactions regarding effects on cell growth and cell death have been studied. Human K-562 cells were pretreated or simultaneously treated with either selenite (5 or 50 microM) or selenomethionine (10 or 50 microM) and with MC (35 or 50 microM). The 35-microM MC treatments resulted in a clear inhibition of cell growth with no obvious difference between mercury-treated and mercury-selenium-treated cells. Furthermore, the apoptotic frequency was similar at all observations for all selenium treatments with 35 microM MC. In the simultaneously treated selenite and 50- microM MC combinations, a selenite-dependent protection was shown both by increased cell growth and by lower apoptotic frequency at 48 and 96 h of exposure. Both treatments with selenomethionine showed protection observed as an increased cell growth at 48 and 96 h and as decreased apoptotic frequency at 96 h of exposure.