title: Intervention of sulfur mustard toxicity by downregulation of cell proliferation and metabolic rates.
abstract: Metabolically active and proliferating basal cells in the skin are most sensitive to the potent skin blistering chemical warfare compound HD (bis-(2-chloroethyl) sulfide). We previously described a Ca2+-dependent mechanism of HD (0.3-1 mM) toxicity that was inhibited by the cell-permeant Ca2+ chelator BAPTA AM (1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester). We describe some cellular effects of BAPTA AM that suggest a mechanism for its protective action. Monolayer log-phase normal human epidermal keratinocytes were incubated (37 degrees C) first in keratinocyte growth medium (KGM) containing BAPTA AM (10-40 microM) for 30 min and then in KGM alone overnight prior to evaluation. The BAPTA AM inhibited cell growth in a concentration-dependent manner with some cellular degeneration above 30 microM (light microscopy). At 20-30 microM, BAPTA AM also inhibited cellular metabolic processes, as evidenced by a lower incorporation of [3H]-thymidine (DNA synthesis, 54 +/- 5%), [3H]-uridine (RNA synthesis, 29 +/- 6%) and [14C]-valine (protein synthesis, 12 +/- 2%) as well as a lower protein content per culture (30 +/- 3%) compared with corresponding untreated controls. However, 20-30 microM BAPTA AM did not cause any demonstrable cytopathology based on morphological (electron microscopy) as well as biochemical (lactate dehydrogenase release, an indicator of cell viability loss) criteria, indicating a lack of acute toxicity. These results suggest that a mechanism of protection by BAPTA AM against HD may be via decreasing some metabolic, and therefore proliferative, rates.
authors: US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, USA. radharaman.ray@amedd.army.mil
authors: R
authors: R
authors: Ray
authors: B J
authors: BJ
authors: Benton
authors: D R
authors: DR
authors: Anderson
authors: S L
authors: SL
authors: Byers
authors: J P
authors: JP
authors: Petrali
mesh_terms: D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects*; D002614:Chelating Agents / Q000494:pharmacology*; D003879:Dermatologic Agents / Q000633:toxicity*; D015536:Down-Regulation; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000502:physiology; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008854:Microscopy, Electron; D009151:Mustard Gas / Q000633:toxicity*; D011041:Poisoning / Q000517:prevention & control; D020011:Protective Agents / Q000494:pharmacology*; D014176:Protein Biosynthesis
chemical_list: D002614:Chelating Agents; D003879:Dermatologic Agents; D020011:Protective Agents; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D007770:L-Lactate Dehydrogenase; D009151:Mustard Gas