Akman S A, Dietrich M, Chlebowski R, Limberg P, Block J B
Cancer Res. 1985 Nov;45(11 Pt 1):5257-62.
We investigated the mechanism of antitumor activity of the water-soluble derivative of menadione, menadione sodium bisulfite (vitamin K3), versus murine leukemia L1210. Vitamin K3, in concentrations greater than 27 microM, caused time- and concentration-dependent depletion of the acid-soluble thiol (GSH) pool. Maximal GSH depletion to 15% of control occurred at 45 microM vitamin K3. Vitamin K3-mediated GSH depletion and vitamin K3-mediated growth inhibition were abrogated by coincubation with 1 mM cysteine or 1 mM reduced glutathione but not by 1 mM ascorbic acid or 180 microM alpha-tocopherol. Low concentrations of vitamin K3 (9-27 microM) elevated both the GSH pool and the total glutathione pool, the latter to a greater degree. Vitamin K3 also caused an increased rate of superoxide anion generation by L1210, maximal at 45 microM vitamin K3 (300% of control), and a concentration-dependent depletion of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) and total nicotinamide adenine dinucleotide phosphate (NADP) pools. Forty-fifty % depletion of the NADPH pool occurred after exposure to 27 microM vitamin K3 and 100% occurred at 36 microM vitamin K3; 27 microM vitamin K3 is a nontoxic concentration of vitamin K3. Loss of NADPH and total NADP was prevented by coincubation with 1 mM cysteine but not by coincubation with ascorbic acid or alpha-tocopherol. We conclude that tumor cell growth inhibition by vitamin K3 is modulated by acid-soluble thiols and may be caused by GSH pool and/or NADPH depletion. Toleration of partial NADPH depletion by L1210 cells may indicate that a threshold level of NADPH loss of greater than 50% is necessary for toxicity. NADPH depletion may be a toxic effect common to quinone drugs. Equitoxic concentrations of vitamin K3, phylloquinone, lapachol, dichlorolapachol, and doxorubicin caused L1210 NADPH pools to deplete to 30 +/- 10 (SD), 60 +/- 10, 60 +/- 11, and 80 +/- 12% of control, respectively. In contrast, GSH depletion may not be a common mechanism of toxicity. Of these quinones, only vitamin K3 caused significant GSH depletion when studied in equitoxic concentrations.
我们研究了甲萘醌的水溶性衍生物亚硫酸氢钠甲萘醌（维生素K3）对小鼠白血病L1210的抗肿瘤活性机制。浓度大于27微摩尔/升的维生素K3会导致酸溶性硫醇（谷胱甘肽）池随时间和浓度而减少。在45微摩尔/升维生素K3时，谷胱甘肽最大减少至对照的15%。与1毫摩尔/升半胱氨酸或1毫摩尔/升还原型谷胱甘肽共同孵育可消除维生素K3介导的谷胱甘肽减少和维生素K3介导的生长抑制，但与1毫摩尔/升抗坏血酸或180微摩尔/升α-生育酚共同孵育则不能。低浓度的维生素K3（9 - 27微摩尔/升）可提高谷胱甘肽池和总谷胱甘肽池，后者提高幅度更大。维生素K3还导致L1210产生超氧阴离子的速率增加，在45微摩尔/升维生素K3时达到最大值（为对照的300%），并使还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）和总烟酰胺腺嘌呤二核苷酸磷酸（NADP）池呈浓度依赖性减少。暴露于27微摩尔/升维生素K3后，NADPH池减少45%，在36微摩尔/升维生素K3时减少100%；27微摩尔/升维生素K3是维生素K3的无毒浓度。与1毫摩尔/升半胱氨酸共同孵育可防止NADPH和总NADP的损失，但与抗坏血酸或α-生育酚共同孵育则不能。我们得出结论，维生素K3对肿瘤细胞生长的抑制作用受酸溶性硫醇调节，可能是由谷胱甘肽池和/或NADPH减少引起的。L1210细胞对部分NADPH减少的耐受性可能表明，毒性所需的NADPH损失阈值水平大于50%。NADPH减少可能是醌类药物共有的毒性作用。等毒性浓度的维生素K3、叶绿醌、拉帕醇、二氯拉帕醇和阿霉素分别使L1210的NADPH池减少至对照的30±10（标准差）、60±10、60±11和80±12%。相比之下，谷胱甘肽减少可能不是常见的毒性机制。在这些醌类中，只有维生素K3以等毒性浓度研究时会导致显著的谷胱甘肽减少。
