Chatterjee P K, Sternberg N L
Cancer Research Group, DuPont Merck Pharmaceutical Company, Glenolden, PA 19036, USA.
Photochem Photobiol. 1995 Apr;61(4):360-6. doi: 10.1111/j.1751-1097.1995.tb08623.x.
In order to understand its mechanism of action we have begun an effort to better define the cellular target of action of the experimental antitumor agent DMP 840 (NSC D640430; (R,R)-2,2'-(1,2-ethanediylbis(imino-(1-methyl-2,1-ethanediyl)))-bi s(5- nitro-1H-benz(de)isoquinoline-1,3-(2H)-dione) dimethanesulfonate). Using a combination of gentle cell fractionation procedures and a previously unidentified photochemical crosslinking reaction, we have shown that after the drug is added to cultured Clone A cells, more than 80% of the drug that is found associated with cells partitions to the chromatin-containing structural framework of the cell and that the primary target after crosslinking with 360 nm light is DNA. While DMP 840 photoreacts quite efficiently with purified RNA in vitro, no photoattachment of the drug to RNA was observed in cells. In vitro photochemical studies also reveal that while GC-rich DNA is a preferred target for drug interaction, AT-rich DNA is more active in the photochemical crosslinking reaction. These results suggest that DMP 840 probably kills cells by interfering with DNA-metabolic processes, and that the drug and its derivatives are likely to be useful photoactive molecular probes for investigating higher order chromatin structures in cells.
为了解其作用机制，我们已着手努力更好地确定实验性抗肿瘤药物DMP 840（NSC D640430；(R,R)-2,2'-(1,2-乙二基双(亚氨基-(1-甲基-2,1-乙二基)))-双(5-硝基-1H-苯并(de)异喹啉-1,3-(2H)-二酮)二甲磺酸盐）的细胞作用靶点。通过结合温和的细胞分级分离程序和一种先前未被识别的光化学交联反应，我们已表明，在将该药物添加到培养的克隆A细胞后，发现与细胞相关的药物中超过80%分配到细胞含染色质的结构框架中，并且在与360 nm光交联后，主要靶点是DNA。虽然DMP 840在体外能与纯化的RNA高效地发生光反应，但在细胞中未观察到该药物与RNA的光附着。体外光化学研究还表明，虽然富含GC的DNA是药物相互作用的首选靶点，但富含AT的DNA在光化学交联反应中更具活性。这些结果表明，DMP 840可能通过干扰DNA代谢过程来杀死细胞，并且该药物及其衍生物可能是用于研究细胞中高阶染色质结构的有用的光活性分子探针。
