Cytotoxicity and apoptosis induction by butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).
The cytotoxicity and apoptosis-inducing activity of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and 2-tert-butyl-4-methylphenol (BMP) and the mixture of BHA and BHT (BHA/BHT) (1:1, molar ratio) were investigated, using human promeylocytic leukemia cell lines (HL-60) and human squamous cell carcinoma cell lines (HSC-2). The 50% cytotoxic concentration (CC50) declined in the order of BHA, BHT (0.2-0.3 mM) > BHA/BHT (0.04-0.07 mM) > BMP (0.02-0.05 mM). The addition of antioxidants (N-acetyl-Lcysteine, sodium ascorbate, catalase) reduced the cytotoxicity of BHA/BHT or BMP against HSC-2 cells, but not that of BHA or BHT, whereas the addition of NADH, a quinone reductase to BMP, enhanced the cytotoxicity. These findings suggested that the cytotoxicity of BHA/BHT and BMP might be caused by reactive intermediates. BHA-induced cytotoxicity was enhanced by horseradish peroxidases, suggesting that BHA was oxidizable and produced cytotoxic BHA radicals. Internucleosomal DNA fragmentation of HL-60 cells was preferably induced by BHA/BHT and BMP, followed by BHA. The MnSOD mRNA expression in HL-60 cells assayed by reverse transcriptase-polymerase chain reaction was highly inhibited by BHA/BHT or BMP, accompanied by the change in the electrophoretic mobility of MnSOD on polyacryamide gel. These compounds activated caspase-3, 8 and 9 in HL-60 cells. Activations of caspases, particularly caspase-3, declined in the order of BHA/BHT > BHA > BMP > BHT. The most cytotoxic BMP activated caspase-3 activity to the least extent, possibly in part due to the occurrence of necrosis. The great cytotoxicity and apoptosis induction by BHA/BHT may be due to reactive intermediates derived from the interaction between BHA phenoxyl radical and BHT or BHT phenoxyl radical.
Saito
Masatoshi
M
Department of Oral Diagnosis, Meikai University School of Dentistry, Saitama 350-0283, Japan.
Sakagami
Hiroshi
H
Fujisawa
Seiichiro
S
D000975:Antioxidants / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D002083:Butylated Hydroxyanisole / Q000633:toxicity*; D002084:Butylated Hydroxytoluene / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002294:Carcinoma, Squamous Cell; D002470:Cell Survival / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D009243:NAD / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D002273:Carcinogens; D012333:RNA, Messenger; D009243:NAD; D002084:Butylated Hydroxytoluene; D002083:Butylated Hydroxyanisole; D013482:Superoxide Dismutase