title: Ruthenium red protects HepG2 cells overexpressing CYP2E1 against acetaminophen cytotoxicity.
abstract: We studied the mechanisms of acetaminophen (APAP) cytotoxicity in HepG2 cells overexpressing cytochrome p4502E1, particularly the role of oxidative/nitrosative stress and ryanodine Ca2+ channel. Cells were grown for 24 h with APAP in the presence or absence of 4-methylpyrazole (4MP), L-arginine methyl ester (L-NAME), superoxide dismutase (SOD), or ruthenium red (RuR). Drug cytotoxicity was also tested in cells pretreated overnight with V-PYRRO/NO. APAP was without effect on empty vector-transfected cells, but damaged CYP2E1-transfected cells and this was abolished by RuR, reduced by 4MP, or V-PYRRO/NO but affected by L-NAME or SOD. APAP increased microsomal [3H]-ryanodine binding, while microsomal Ca2+ uptake was significantly lowered. RuR increased net microsomal Ca2+ uptake and normalized cytosolic Ca2+ levels. We can conclude that neither oxidative nor nitrosative stress is relevant to APAP cytotoxicity in cultured HepG2 cells, but our results point to ryanodine receptors as a potential crucial protein in the early stages of APAP cytotoxicity.
authors.affiliation: Department of Clinical Pharmacology, Medical Academy at Bialystok, Waszyngtona 15A, 15-274, Bialystok, Poland. Holow_Sinai@hotmail.com
authors.forename: Adam
authors.initials: A
authors.lastname: Holownia
authors.forename: Jakub
authors.initials: J
authors.lastname: Jablonski
authors.forename: Anna
authors.initials: A
authors.lastname: Skiepko
authors.forename: Robert
authors.initials: R
authors.lastname: Mroz
authors.forename: Edyta
authors.initials: E
authors.lastname: Sitko
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Braszko