Intervention of sulfur mustard toxicity by downregulation of cell proliferation and metabolic rates

• Published in: Journal of applied toxicology 2000-12, Vol.20 (S1), p.S87-S91
• Main Authors: Ray, R., Benton, B. J., Anderson, D. R., Byers, S. L., Petrali, J. P.
• Format: Article
• Language: English
• Subjects: BAPTA AM; Biological and medical sciences; Cell Culture Techniques; Cell Division - drug effects; cell metabolism; cell proliferation; Chelating Agents - pharmacology; Chemical and industrial products toxicology. Toxic occupational diseases; Dermatologic Agents - toxicity; DNA synthesis; Down-Regulation; Egtazic Acid - analogs & derivatives; Egtazic Acid - pharmacology; Gas, fumes; Humans; Keratinocytes - drug effects; Keratinocytes - physiology; L-Lactate Dehydrogenase - analysis; Medical sciences; Microscopy, Electron; Mustard Gas - toxicity; NHEK; Poisoning - prevention & control; protection; Protective Agents - pharmacology; Protein Biosynthesis; protein synthesis; RNA synthesis; sulfur mustard; toxicity; Toxicology
• ISSN: 0260-437X; 1099-1263
• DOI: 10.1002/1099-1263(200012)20:1+<::AID-JAT683>3.0.CO;2-N

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°C) first in keratinocyte growth medium (KGM) containing BAPTA AM (10–40 μM) 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 μM (light microscopy). At 20–30 μM, BAPTA AM also inhibited cellular metabolic processes, as evidenced by a lower incorporation of [3H]‐thymidine (DNA synthesis, 54 ± 5%), [3 H]‐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 μM 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. Published in 2000 by John Wiley & Sons, Ltd.