Accumulation and toxicity of monophenyl arsenicals in rat endothelial cells.
Clark 1 (diphenylarsine chloride) and Clark 2 (diphenylarsine cyanide) were used as chemical weapon agents (CWA), and the soil contamination by these CWA and their degraded products, diphenyl and phenyl arsenicals, has been one of the most serious environmental issues. In a series of comparisons in toxicity between trivalent and pentavalent arsenicals we investigated differences in the accumulation and toxicity of phenylarsine oxide (PAO3+) and phenylarsonic acid (PAA5+) in rat heart microvascular endothelial cells. Both the cellular association and toxicity of PAO3+ were much higher than those of PAA5+, and LC50 values of PAO3+ and PAA5+ were calculated to be 0.295 microM and 1.93 mM, respectively. Buthionine sulfoximine, a glutathione depleter, enhanced the cytotoxicity of both PAO3+ and PAA5+. N-Acetyl-L-cysteine (NAC) reduced the cytotoxicity and induction of heme oxygenase-1 (HO-1) mRNA in PAO3+-exposed cells, while NAC affected neither the cytotoxicity nor the HO-1 mRNA level in PAA5+-exposed cells. The effect of NAC may be due to a strong affinity of PAO3+ to thiol groups because both NAC and GSH inhibited the cellular accumulation of PAO3+, but PAA3+ increased tyrosine phosphorylation levels of cellular proteins. These results indicate that the inhibition of protein phosphatases as well as the high affinity to cellular components may confer PAO3+ the high toxicity.
Hirano
Seishiro
S
Environmental Health Sciences Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506, Ibaraki, Japan. seishiro@nies.go.jp
Kobayashi
Yayoi
Y
Hayakawa
Toru
T
Cui
Xing
X
Yamamoto
Megumi
M
Kanno
Sanae
S
Shraim
Amjad
A
D000818:Animals; D001152:Arsenicals / Q000493:pharmacokinetics / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003331:Coronary Vessels / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis; D051547:Heme Oxygenase-1; D010766:Phosphorylation; D051381:Rats; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism
D001152:Arsenicals; C029341:oxophenylarsine; D014443:Tyrosine; C020979:benzenearsonic acid; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1