Gascoigne E W, Robinson A C, Harris W J
Chem Biol Interact. 1981 Jul;36(1):107-16. doi: 10.1016/0009-2797(81)90032-6.
It has been found that in BHK 21 cells caffeine potentiates cell killing by both UV irradiation and N-methyl-N-nitrosoguanidine (MNNG). The potentiating effect is greater with UV than with MNNG. While non-toxic concentrations of caffeine inhibit the joining of newly-replicated DNA fragments into large molecular weight DNA (post-replication repair) after UV irradiation, they have no such effect after MNNG treatment. Furthermore, the joining of DNA fragments continues in the cells treated with 3 microgram/ml of MNNG, a dose which leads to less than 5% cell survival. While inhibition of the synthesis of large molecular weight DNA can explain the synergistic effect of caffeine upon cell survival after UV irradiation, it cannot explain the similar effect after MNNG treatment.
现已发现，在BHK 21细胞中，咖啡因可增强紫外线照射和N-甲基-N-亚硝基胍（MNNG）对细胞的杀伤作用。咖啡因对紫外线照射的增强作用比对MNNG的增强作用更大。虽然无毒浓度的咖啡因可抑制紫外线照射后新复制的DNA片段连接成大分子DNA（复制后修复），但在MNNG处理后却没有这种作用。此外，在用3微克/毫升MNNG处理的细胞中，DNA片段的连接仍在继续，该剂量导致细胞存活率低于5%。虽然抑制大分子DNA的合成可以解释咖啡因对紫外线照射后细胞存活的协同作用，但无法解释MNNG处理后的类似作用。
