The phenanthridine alkaloid lycobetaine is a minor constituent of Amaryllidaceae. Inhibition of cell growth was studied in the clonogenic assay on 21 human tumour xenografts (mean IC 50 = 0.8 μM). The growth of human leukaemia cell lines was also potently inhibited (mean IC 50 = 1.3 μM). Athymic nude mice, carrying s.c. implanted human gastric tumour xenograft GXF251, were treated i.p. with lycobetaine for 4 weeks, resulting in a marked tumour growth delay. Lycobetaine was found to act as a specific topoisomerase IIβ poison, in the presence of calf thymus DNA, pure recombinant human topoisomerase IIβ protein was selectively depleted from SDS-gels, whereas no depletion of topoisomerase IIα protein was observed. In A431 cells immunoband-depletion of topoisomerase IIβ was induced, suggesting stabilization of the covalent catalytic DNA-intermediate in living cells. It is reasonable to assume that this mechanism will cause or at least contribute significantly to the antitumour activity. © 2001 Cancer Research Campaign.
CITATION STYLE
Barthelmes, H. U., Niederberger, E., Roth, T., Schulte, K., Tang, W. C., Boege, F., … Marko, D. (2001). Lycobetaine acts as a selective topoisomerase IIβ poison and inhibits the growth of human tumour cells. British Journal of Cancer, 85(10), 1585–1591. https://doi.org/10.1054/bjoc.2001.2142
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