N-Chloroamino acids mediate the action of hypochlorite on A549 lung cancer cells in culture

Hypochlorous acid, a chlorinating and oxidative agent, has been reported to be implicated in many pathologies. Its markers were found under inflammatory conditions and, at least some of it reveals biological activity. Thus, in this paper we examined whether N-chloroamino acids may act as mediators of the action of hypochlorous acid in cell culture. N-Chloroamino acids were found to possess lower oxidative capacity than HOCl/OCl- just after addition to the growth medium. However, all the chlorocompounds studied were cytotoxic to A549 cells, induced a dose-dependent increase in the G(0)/G(1) fraction with simultaneous reduction in the G(2)/M fraction, collapse of the mitochondrial potential and caspase-dependent apoptosis. The content of cellular thiols decreased after 1-h incubation with the chlorocompounds studied. Although amino acids act as scavengers of hypochlorite in plasma, the chlorinated products formed stay reactive and the pattern of their action on cells in vitro is similar to that of hypochlorite. (C) 2010 Elsevier Ireland Ltd. All rights reserved.