Differences in the growth inhibition of cultured K-562 cells by selenium, mercury or cadmium in two tissue culture media (RPMI-1640, Ham's F-10)

Effects of some metals on the growth of cultured human erythroleukemia K-56 2 cells were investigated when grown in two different types of media based upon RPMI-1640 or Ham's F-10. The study on proliferation, using RPMI-1640 s upplemented with sodium selenite, selenomethionine, mercuric chloride, meth ylmercuric chloride and cadmium nitrate showed no inhibition of growth at c oncentrations of 2.5, 25, 25, 2.5 and 25 mu M, while at 75, 250, 50, 5 and 50 mu M toxicity was apparent. Selenite at 5-50 mu M and selenomethionine a t 50-100 mu M inhibited the growth. In Ham's F-10 supplemented with the sam e compounds no inhibition was found at concentrations of 5, 10, 25, 1 and 5 0 mu M, while at 50, 100, 50, 5 and 75 mu M toxic effects were noted. Selen ite 10 mu M and selenomethionine 25-50 mu M inhibited the proliferation. Me asurements of trace element levels in pellets of K-562 cells grown in RPMI- 1640 or Ham's F-10 unveiled higher cell contents of cadmium and selenium in cells grown in RPMI-1640, being consistent with higher concentrations of t hese elements in that medium. Manganese and mercury concentrations were hig her in cells grown in Ham's F-10 correlating with a higher medium concentra tion of these elements. The growth responses and cellular uptake differed b etween the metals and the selenocompounds and although extrapolating the re sults to humans is difficult the selenium exposures were in approximately t he same order of magnitude as in human exposures. The compounds could be ra nked according to decreasing toxicity as: methylmercuric chloride > mercuri c chloride, cadmium nitrate, sodium selenite > selenomethionine.