8-hydroxydeoxyguanosine causes death of human leukemia cells deficient in 8-oxoguanine glycosylase 1 activity by inducing apoptosis.
Our previous study showed that KG-1, a human acute leukemia cell line, has mutational loss of 8-oxoguanine (8-hydroxyguanine; oh(8)Gua) glycosylase 1 (OGG1) activity and that its viability is severely affected by 8-hydroxydeoxyguanosine (8-oxodeoxyguanosine; oh(8)dG). In the present study, the nature of the killing action of oh(8)dG on KG-1 was investigated. Signs observed in oh(8)dG-treated KG-1 cells indicated that death was due to apoptosis, as demonstrated by: increased sub-G(1) hypodiploid (apoptotic) cells, DNA fragmentation, and apoptotic body formation; loss of mitochondrial transmembrane potential, the release of cytochrome c from mitochondria into the cytosol, and the down-regulation of bcl-2; and the activation of caspases 8, 9, and 3, and the efficient inhibition of the apoptotic process by caspases inhibitors. This apoptosis appears not to be associated with Fas/Fas ligand because the expressions of these proteins were unchanged. Apoptotic KG-1 cells showed a high concentration of oh(8)Gua in DNA. Moreover, the increased concentration of oh(8)Gua in DNA, and the apoptotic process were not suppressed by the antioxidant, N-acetylcysteine, and thus the process is independent of reactive oxygen species. Of the 18 cancer cell lines treated with oh(8)dG, 3 cell lines (H9, CEM-CM3, and Molt-4) were found to be committed to apoptosis, and all of these showed very low OGG1 activity and a marked increase in the concentration of oh(8)Gua in DNA. These observations indicate that in addition to its mutagenic action, oh(8)Gua in DNA disturbs cell viability by inducing apoptosis.
Hyun
Jin-Won
JW
Department of Pharmacology, Seoul National University College of Medicine, Chongno-gu, South Korea.
Jung
Yoon-Chul
YC
Kim
Hyun-Sook
HS
Choi
Eun-Young
EY
Kim
Ja-Eun
JE
Yoon
Byung-Hak
BH
Yoon
Sun-Hee
SH
Lee
Yun-Sil
YS
Choi
Jinhee
J
You
Ho-Jin
HJ
Chung
Myung-Hee
MH
D000080242:8-Hydroxy-2'-Deoxyguanosine; D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D043382:DNA-Formamidopyrimidine Glycosylase / Q000172:deficiency* / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000633:toxicity; D029968:Escherichia coli Proteins / Q000378:metabolism; D053222:Fas Ligand Protein; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007938:Leukemia / Q000201:enzymology* / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
D029968:Escherichia coli Proteins; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; D019014:fas Receptor; C024829:8-hydroxyguanine; D006147:Guanine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli; D003849:Deoxyguanosine