Inhibition of DNA topoisomerase I activity and induction of apoptosis by thiazacridine derivatives

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• 作者：Francisco W.A. Barros^a ; Daniel P. Bezerra^b ; ^{danielpbezerra@gmail.com} ; Paulo M.P. Ferreira^c ; Bruno C. Cavalcanti^a ; Teresinha G. Silva^d ; Marina G.R. Pitta^d ; Maria do C.A. de Lima^d ; Suely L. Galdino^d ; Ivan da R. Pitta^d ; Letí ; cia V. Costa-Lotufo^a ; Manoel O. Moraes^a ; Rommel R. Burbano^e ; Temenouga N. Guecheva^f ; Joã ; o A.P. Henriques^f ; Clá ; udia Pessoa^a ; ^{cpessoa@ufc.br}
• 关键词：Acridine ; Thiazolidine ; Thiazacridine ; DNA topoisomerase I ; Apoptosis
• 刊名：Toxicology and Applied Pharmacology
• 出版年：2013
• 出版时间：1 April, 2013
• 年：2013
• 卷：268
• 期：1
• 页码：37-46
• 全文大小：1027 K

文摘

Thiazacridine derivatives (ATZD) are a novel class of cytotoxic agents that combine an acridine and thiazolidine nucleus. In this study, the cytotoxic action of four ATZD were tested in human colon carcinoma HCT-8 cells: (5Z)-5-acridin-9-ylmethylene-3-(4-methylbenzyl)-thiazolidine-2,4-dione ¡ª AC-4; (5ZE)-5-acridin-9-ylmethylene-3-(4-bromo-benzyl)-thiazolidine-2,4-dione ¡ª AC-7; (5Z)-5-(acridin-9-ylmethylene)-3-(4-chloro-benzyl)-1,3-thiazolidine-2,4-dione ¡ª AC-10; and (5ZE)-5-(acridin-9-ylmethylene)-3-(4-fluoro-benzyl)-1,3-thiazolidine-2,4-dione ¡ª AC-23. All of the ATZD tested reduced the proliferation of HCT-8 cells in a concentration- and time-dependent manner. There were significant increases in internucleosomal DNA fragmentation without affecting membrane integrity. For morphological analyses, hematoxylin-eosin and acridine orange/ethidium bromide were used to stain HCT-8 cells treated with ATZD, which presented the typical hallmarks of apoptosis. ATZD also induced mitochondrial depolarisation and phosphatidylserine exposure and increased the activation of caspases 3/7 in HCT-8 cells, suggesting that this apoptotic cell death was caspase-dependent. In an assay using Saccharomyces cerevisiae mutants with defects in DNA topoisomerases 1 and 3, the ATZD showed enhanced activity, suggesting an interaction between ATZD and DNA topoisomerase enzyme activity. In addition, ATZD inhibited DNA topoisomerase I action in a cell-free system. Interestingly, these ATZD did not cause genotoxicity or inhibit the telomerase activity in human lymphocyte cultures at the experimental levels tested. In conclusion, the ATZD inhibited the DNA topoisomerase I activity and induced tumour cell death through apoptotic pathways.