DNA Topoisomerase II Inhibition by Peroxisomicine A1 and Its Radical Metabolite Induces Apoptotic Cell Death of HL-60 and HL-60/MX2 Human Leukemia Cells

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• 作者：Am&eacute ; lie Lansiaux ; William Laine ; Brigitte Baldeyrou ; Christine Mahieu ; Nicole Wattez ; Herv&eacute ; Vezin ; Francisco J. Martinez ; Alfredo Piñ ; eyro ; and Christian Bailly
• 刊名：Chemical Research in Toxicology
• 出版年：2001
• 出版时间：January 2001
• 年：2001
• 卷：14
• 期：1
• 页码：16 - 24
• 全文大小：382K
• 年卷期：v.14,no.1(January 2001)
• ISSN：1520-5010

文摘

Peroxisomicine A₁ (T-514) is a dimeric anthracenone first isolated from the plant Karwinskiahumboldtiana. The compound presents a high and selective toxicity toward liver and skin cellcultures and is currently the subject of preclinical studies as an antitumor drug. To date, themolecular basis for its diverse biological effects remains poorly understood. To elucidate itsmechanism of action, we studied its interaction with DNA and its effects on human DNAtopoisomerases. Practically no interaction with DNA was detected. Peroxisomicine was foundto inhibit topoisomerase II but not topoisomerase I. DNA relaxation and decatenation assaysindicated that the drug interferes with the catalytic activity of topoisomerase II but does notstimulate DNA cleavage, in contrast to conventional topoisomerase poisons such as etoposide.Two human leukemia cell lines sensitive or resistant to mitoxantrone were used to assess thecytotoxicity of the toxin and its effect on the cell cycle. In both cases, peroxisomicine treatmentwas associated with a loss of cells from every phase of the cell cycle and was accompanied bya large increase in the sub-G1 region which is characteristic of apoptotic cells. The cell cyclechanges were more pronounced with the sensitive HL-60 cells than with the resistant HL-60/MX2 cells (with reduced topoisomerase II activity), in agreement with the cytotoxicitymeasurements. Treatment of HL-60 cells with T-514 stimulated the cleavage of the poly(ADP-ribose) polymerase by intracellular proteases such as caspase-3. The cytometry and Westernblot analyses reveal that peroxisomicine induces apoptosis in leukemia cells. In addition, wecharacterized a catabolite of peroxisomicine, named T-510R, in the form of a highly stableradical metabolite. The electron spin resonance and mass spectrometry data are consistentwith the formation of an anionic semiquinonic radical. The oxidized product T-510R inhibitstopoisomerase II with a reduced efficiency compared to the parent toxin and was found to beabout 3-4 times less toxic to both the sensitive and resistant leukemia cell lines than T-514.Collectively, the results suggest that topoisomerase II inhibition plays a role in the cytotoxicityof the plant toxin peroxisomicine. Inhibition of topoisomerase II may serve as an inducingsignal triggering the apoptotic cell death of leukemia cells exposed to the toxin. Thedihydroxyanthracenone unit may represent a useful chemotype for the preparation oftopoisomerase II-targeted anticancer agents.