Effects of a series of triorganotins on ATP levels in human natural killer cells

Abstract

Natural killer (NK) cells are our initial immune defense against viral infections and cancer development. Thus, agents that are able to interfere with their function increase the risk of cancer and/or infection. A series of triorganotins (trimethyltin (TMT), dimethylphenyltin (DMPT), methyldiphenyltin (MDPT), and triphenyltin (TPT)) have been shown to decrease the lytic function of human NK cells. TPT and MDPT were much more effective than DMPT or TMT at reducing lytic function. This study investigates the role that decreased ATP levels may play in decreases in the lytic function of NK cells induced by these organotins (OTs). A 24 h exposure to as high as 10 μM TMT caused no decrease in ATP levels even though this level of TMT caused a greater than 75% loss of lytic function. TPT at 200 nM caused a decrease in ATP levels of about 20% while decreasing lytic function by greater than 85%. There was no association between ATP levels and lytic function for any of the compounds when NK cells were exposed for 1 or 24 h. However, after a 48 h exposure to both DMPT and TPT decreased lytic function was associated with decreased ATP levels. There was an association between decreased lytic function and decreased ATP levels after a 6-day exposure to each of the four compounds. These studies indicate that the loss of lytic function seen after 1 and 24 h exposures to this series of organotins cannot be accounted for by decreases in ATP. However, after longer exposures loss of lytic function may be in part be attributable to inadequate ATP levels.