Yamamoto K, Tsukidate K, Farber J L
Department of Pathology, Thomas Jefferson University, Philadelphia, PA 19107.
Biochem Pharmacol. 1993 Aug 3;46(3):483-91. doi: 10.1016/0006-2952(93)90525-2.
The effects of the two inhibitors of poly(ADP-ribose) polymerase, 3-aminobenzamide (ABA) and benzamide (BA), on the oxidative killing of L929 mouse fibroblasts and primary cultures of rat hepatocytes were studied. The killing of L929 cells by tert-butyl hydroperoxide (TBHP) occurred by two mechanisms, one sensitive and the other insensitive to the antioxidant N,N'-diphenylphenylene diamine (DPPD). Cell killing by either mechanism was prevented by the ferric iron chelator deferoxamine. ABA and BA prevented the killing of L929 cells that occurred in the presence, but not in the absence, of DPPD. ABA and BA inhibited the activity of poly(ADP-ribose) polymerase by 85%. Protection was accompanied by the sparing of the depletion of both NAD and ATP, but there was no effect of either ABA or BA on the iron-dependent appearance of single-strand breaks in DNA. Depletion of ATP by treating the fibroblasts with 2-deoxyglucose and sodium azide did not result in any loss of viability. H2O2 similarly killed the L929 cells by a mechanism that depended on a source of ferric iron. However, DPPD had no effect on the cell killing, and ABA and BA completely protected the cells in the presence or absence of DPPD. H2O2 caused the appearance of single-strand breaks that were prevented by deferoxamine, but again not by ABA or BA. ABA and deferoxamine reduced, but did not prevent, the depletion of both NAD and ATP occurring with H2O2. With the cultured hepatocytes, ABA and BA inhibited poly(ADP-ribose) polymerase at concentrations that were without effect on either the extent of cell killing or the depletion of NAD occurring with either TBHP, H2O2, or menadione. These data indicate that the relationship between oxidative DNA damage and the genesis of lethal injury is very different in the two types of cells. In the fibroblasts, the appearance of single strand breaks in DNA was accompanied by depletion of NAD and ATP and subsequently by the death of the cells. These events were mediated by the activity of poly(ADP-ribose) polymerase, as inhibition of the enzyme prevented their development. In the hepatocytes, inhibition of poly(ADP-ribose) polymerase was without effect on the oxidative death of the cells.
研究了两种聚（ADP - 核糖）聚合酶抑制剂3 - 氨基苯甲酰胺（ABA）和苯甲酰胺（BA）对L929小鼠成纤维细胞和大鼠肝细胞原代培养物氧化杀伤的影响。叔丁基过氧化氢（TBHP）对L929细胞的杀伤通过两种机制发生，一种对抗氧化剂N，N'-二苯基对苯二胺（DPPD）敏感，另一种不敏感。两种机制导致的细胞杀伤均被铁螯合剂去铁胺阻止。ABA和BA阻止了在有DPPD存在时而非无DPPD时发生的L929细胞杀伤。ABA和BA将聚（ADP - 核糖）聚合酶的活性抑制了85%。保护作用伴随着NAD和ATP消耗的减少，但ABA或BA对DNA中单链断裂的铁依赖性出现均无影响。用2 - 脱氧葡萄糖和叠氮化钠处理成纤维细胞导致ATP消耗，但未导致任何活力丧失。H2O2同样通过依赖于铁源的机制杀死L929细胞。然而，DPPD对细胞杀伤无影响，ABA和BA在有或无DPPD的情况下均能完全保护细胞。H2O2导致单链断裂的出现，去铁胺可阻止其发生，但ABA或BA不能。ABA和去铁胺减少了但未阻止H2O2导致的NAD和ATP消耗。对于培养的肝细胞，ABA和BA在对TBHP、H2O2或甲萘醌导致的细胞杀伤程度或NAD消耗均无影响的浓度下抑制聚（ADP - 核糖）聚合酶。这些数据表明，氧化DNA损伤与致死性损伤发生之间的关系在两种细胞类型中非常不同。在成纤维细胞中，DNA中单链断裂的出现伴随着NAD和ATP的消耗，随后细胞死亡。这些事件由聚（ADP - 核糖）聚合酶的活性介导，因为该酶的抑制阻止了它们的发展。在肝细胞中，聚（ADP - 核糖）聚合酶的抑制对细胞的氧化死亡没有影响。
