Inhibition of Na(+)/K(+)-ATPase and cytotoxicity of a few selected gold(III) complexes.

Voin Petrović, Sandra Petrović, Gordana Joksić, Jasmina Savić, Mirjana Čolović, Maria Agostina Cinellu, Lara Massai, Luigi Messori, Vesna Vasić

Index: J. Inorg. Biochem. 140 , 228-35, (2014)

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Abstract

Na(+)/K(+)-ATPase is in charge of maintaining the ionic and osmotic intracellular balance by using ATP as an energy source to drive excess Na(+) ions out of the cell in exchange for K(+) ions. We explored whether three representative cytotoxic gold(III) compounds might interfere with Na(+)/K(+)-ATPase and cause its inhibition at pharmacologically relevant concentrations. The tested complexes were [Au(bipy)(OH)2][PF6] (bipy=2,2'-bipyridine), [Au(py(dmb)-H)(CH3COO)2] (py(dmb)-H=deprotonated 6-(1,1-dimethylbenzyl)-pyridine), and [Au(bipy(dmb)-H)(OH)][PF6] (bipy(dmb)-H=deprotonated 6-(1,1-dimethylbenzyl)-2,2'-bipyridine). We found that all of them caused a pronounced and similar inhibition of Na(+)/K(+)-ATPase activity. Inhibition was found to be non-competitive and reversible. Remarkably, treatment with cysteine resulted in reversal or prevention of Na(+)/K(+)-ATPase inhibition. It is very likely that the described effects may contribute to the overall cytotoxic profile of these gold complexes. Copyright © 2014 Elsevier Inc. All rights reserved.