Taatjes D J, Fenick D J, Koch T H
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA.
Chem Res Toxicol. 1999 Jul;12(7):588-96. doi: 10.1021/tx990008q.
The anthracycline, antitumor drugs doxorubicin (DOX), daunorubicin (DAU), and epidoxorubicin (EPI) catalyze production of formaldehyde through induction of oxidative stress. The formaldehyde then mediates covalent bonding of the drugs to DNA. Synthetic formaldehyde conjugates of DOX, DAU, and EPI, denoted Doxoform (DOXF), Daunoform (DAUF), and Epidoxoform (EPIF), exhibit enhanced toxicity to anthracycline-sensitive and -resistant tumor cells. Uptake and retention of parent anthracycline antitumor drugs (DOX, DAU, and EPI) relative to those of their formaldehyde conjugates (DOXF, DAUF, and EPIF) were assessed by flow cytometry in both drug-sensitive MCF-7 cells and drug-resistant MCF-7/ADR cells. The MCF-7 cells took up more than twice as much drug as the MCF-7/ADR cells, and both cell lines took up substantially more of the formaldehyde conjugates than the parent drugs. Both MCF-7 and MCF-7/ADR cells retained fluorophore from DOXF, DAUF, and EPIF hours after drug removal, while both cell lines almost completely expelled DOX, DAU, and EPI within 1 h. Longer treatment with DOX, DAU, and EPI resulted in modest drug retention in MCF-7 cells following drug removal but poor retention of DOX, DAU, and EPI in MCF-7/ADR cells. Fluorescence microscopy showed that the formaldehyde conjugates targeted the nuclei of both sensitive and resistant cells, and remained in the nucleus hours after drug removal. Experiments in which [(3)H]Doxoform was used, synthesized from doxorubicin and [(3)H]formaldehyde, also indicated that Doxoform targeted the nucleus. Elevated levels of (3)H were observed in DNA isolated from [(3)H]Doxoform-treated MCF-7 and MCF-7/ADR cells relative to controls. The results implicate drug-DNA covalent bonding in the tumor cell toxicity mechanism of these anthracyclines.
蒽环类抗肿瘤药物阿霉素（DOX）、柔红霉素（DAU）和表柔比星（EPI）通过诱导氧化应激催化甲醛生成。然后甲醛介导药物与DNA的共价结合。DOX、DAU和EPI的合成甲醛缀合物，分别称为多柔比星甲醛（DOXF）、柔红霉素甲醛（DAUF）和表柔比星甲醛（EPIF），对蒽环类敏感和耐药肿瘤细胞表现出增强的毒性。通过流式细胞术评估了药物敏感的MCF-7细胞和耐药的MCF-7/ADR细胞中母体蒽环类抗肿瘤药物（DOX、DAU和EPI）与其甲醛缀合物（DOXF、DAUF和EPIF）的摄取和保留情况。MCF-7细胞摄取的药物量是MCF-7/ADR细胞的两倍多，并且两种细胞系摄取的甲醛缀合物都比母体药物多得多。在去除药物数小时后，MCF-7和MCF-7/ADR细胞都保留了来自DOXF、DAUF和EPIF的荧光团，而两种细胞系在1小时内几乎完全排出了DOX、DAU和EPI。用DOX、DAU和EPI进行更长时间的处理导致去除药物后MCF-7细胞中有适度的药物保留，但在MCF-7/ADR细胞中DOX、DAU和EPI的保留较差。荧光显微镜显示，甲醛缀合物靶向敏感和耐药细胞的细胞核，并且在去除药物数小时后仍留在细胞核中。使用由阿霉素和[³H]甲醛合成的[³H]多柔比星甲醛进行的实验也表明多柔比星甲醛靶向细胞核。相对于对照，在从[³H]多柔比星甲醛处理的MCF-7和MCF-7/ADR细胞中分离的DNA中观察到³H水平升高。结果表明药物与DNA的共价结合参与了这些蒽环类药物的肿瘤细胞毒性机制。
