Jobson AG, Willmore E, Tilby MJ, Mistry P, Charlton P, Austin CA. Effect of phenazine compounds XR11576 and XR5944 on DNA topoisomerases.
Cancer Chemother Pharmacol 2008;
63:889-901. [PMID:
18679685 DOI:
10.1007/s00280-008-0812-9]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 07/20/2008] [Indexed: 11/26/2022]
Abstract
PURPOSE
Previous in vitro cleavage data showed that XR11576 and XR5944 stabilised topoisomerase I and topoisomerase II complexes on DNA in a dose-dependent fashion. However, some studies indicated a possible topoisomerase-independent mechanism of action for these drugs.
METHODS
Three methods, the TARDIS assay, immunoband depletion and the K(+)/SDS assay have been used to assess topoisomerase complex formation induced by XR11576 or XR5944 in human leukaemic K562 cells.
RESULTS
TARDIS and immunoband depletion assays demonstrated that XR11576 and XR5944 induced complex formation for both topoisomerase I and topoisomerase II (alpha and beta) in a dose- and time-dependent manner, following exposure times of 24 and 48 h at concentrations of 1 or 10 microM. The K(+)/SDS assay showed the formation of protein/DNA complexes after a 1 h exposure to 1 or 10 muM XR11576.
CONCLUSION
Our data confirm that XR11576 or XR5944 can form topoisomerase complexes, after long periods of exposure.
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