Biochemical pharmacology of penclomedine (NSC-338720).
Biochemical pharmacology of penclomedine (NSC-338720).
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DOI：
10.1016/0006-2952(95)00251-t
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发表时间：
1995-10
影响因子：
5.8
通讯作者：
J. Benvenuto;W. Hittelman;L. Zwelling;W. Plunkett;T. Pandita;D. Farquhar;R. Newman
中科院分区：
文献类型：
--
作者：
J. Benvenuto;W. Hittelman;L. Zwelling;W. Plunkett;T. Pandita;D. Farquhar;R. Newman
喷氯米定 (PEN) 是一种合成吡啶衍生物，因其对植入小鼠体内的人类和小鼠乳腺肿瘤的活性而被选择用于临床开发。其作用机制尚不清楚，我们有兴趣确定其体外和体内细胞毒性机制。我们发现用 200 mg/kg PEN 处理的 BD2F1 小鼠的 P388 腹水细胞中存在染色体断裂、缺口和交换。观察到的最大损伤发生在给药后 24 小时。碱性洗脱表明仅有有限的 DNA 链断裂和链间交联。在体外，PEN (75 μg/mL) 几乎完全抑制 RNA 和 DNA 合成。此外，在小牛胸腺 DNA 存在的情况下，将 [14C]PEN 与大鼠肝脏 S-9 级分一起孵育，导致放射性稳定转移至 DNA。在孵育混合物中添加丁基羟基甲苯（一种自由基清除剂）可抑制药物与 DNA 的结合，表明自由基是最终的反应物质。这些数据表明，PEN 可以代谢为自由基、DNA 反应产物，其细胞毒性是由于单官能烷基化产生的染色体损伤所致。作为替代机制，PEN 抑制细胞二氢乳清酸脱氢酶的能力得到了探索。尽管 PEN 在体内、体外和分离的细胞超声处理中是该酶的抑制剂，但对 P388 细胞中核糖核苷酸三磷酸池的 HPLC 分析表明，所有三磷酸盐均增加，尤其是 UTP。在细胞培养物中添加尿苷未能阻止 PEN 介导的细胞毒性，表明抑制从头嘧啶生物合成不太可能是该药物的重要作用机制。这些数据表明 PEN 在细胞中被激活，产生结合 DNA 的自由基。
Penclomedine (PEN) is a synthetic pyridine derivative that has been selected for clinical development based on its activity against human and mouse breast tumors implanted in mice. Its mechanism of action was unclear, and we were interested in determining its mechanism of cytotoxicity in vitro and in vivo. We found chromosome breaks, gaps, and exchanges in P388 ascites cells from BD2F1mice treated with 200 mg/kg PEN. Maximal observed damage occurred 24 hr after drug administration. Alkaline elution indicated only limited DNA strand breaks and interstrand cross-linking. In vitro, PEN (75 μg/mL) inhibited RNA and DNA syntheses almost completely. In addition, incubation of [14C]PEN with rat liver S-9 fraction in the presence of calf thymus DNA resulted in the stable transfer of radioactivity to DNA. Addition of butylated hydroxytoluene, a free radical scavenger, to the incubation mixture inhibited the binding of drug to DNA, implicating free radicals as the ultimate reactive species. These data suggest that PEN can be metabolized to free radical, DNA-reactive products, and that its cytotoxicity is due to chromosomal damage produced by monofunctional alkylation. As an alternate mechanism, the ability of PEN to inhibit cellular dihydroorotate dehydrogenase was explored. Although PEN is an inhibitor of this enzyme in cells in vivo, in vitro, and in isolated cell sonicates, HPLC analyses of ribonucleotide triphosphate pools in P388 cells showed that all triphosphates had increased, especially UTP. Addition of uridine to the cell culture failed to prevent PEN-mediated cytotoxicity, suggesting that inhibition of de novo pyrimidine biosynthesis was not likely to be an important mechanism of action of this drug. These data suggest that PEN is activated in cells to a free radical that binds DNA.