title: DNA interaction and dual topoisomerase I and II inhibition properties of the anti-tumor drug prodigiosin.
abstract: Prodigiosin is a red pigment produced by Serratia marcescens with apoptotic activity. We examined the mechanism of action of this tripyrrole alkaloid, focusing on its interaction with DNA and its ability to inhibit both topoisomerase I and topoisomerase II. We also evaluated the DNA damage induced in cancer cell lines. Prodigiosin-DNA intercalation was analyzed using a competition dialysis assay with different DNA base sequences. Topoisomerase I and II inhibition was studied in vitro by a cleavage assay, and in cultured cells, by analysis of its ability to form covalent complexes. Furthermore, we analyzed DNA damage by pulse-field gel electrophoresis and by immunocytochemistry. Apoptosis inducing factor (AIF)/phospho-H2AX (p-H2AX) double labeling by confocal microscopy was performed to determine the possible implication of AIF in the prodigiosin-DNA damage. Finally, we studied the ability of this drug to induce copper-mediated DNA damage at different pH by a DNA cleavage assay. Our results demonstrate prodigiosin-DNA interaction in vitro and in cultured cells. It involves prodigiosin-DNA intercalation, with some preference for the alternating base pairs but with no discrimination between AT or CG sequences, dual abolition of topoisomerase I and II activity and, as consequence, DNA cleavage. Prodigiosin-DNA damage is independent of AIF. Furthermore, we found that copper-mediated cleavage activity is associated with pH (occurring at pH 6.8 rather than pH 7.4) and with the Cu(2+) ion concentration. These results indicate DNA a therapeutic target for prodigiosin and could explain the apoptosis mechanism of action induced by this antineoplastic drug.
authors.affiliation: Departament de Biologia Cellular i Anatomia Patològica, Cancer Cell Biology Research Group, Universitat de Barcelona, Barcelona, Spain E-08907.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Montaner
authors.forename: Wilmar
authors.initials: W
authors.lastname: Castillo-Avila
authors.forename: Marc
authors.initials: M
authors.lastname: Martinell
authors.forename: Rupert
authors.initials: R
authors.lastname: Ollinger
authors.forename: Joan
authors.initials: J
authors.lastname: Aymami
authors.forename: Ernest
authors.initials: E
authors.lastname: Giralt
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pérez-Tomás
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001667:Binding, Competitive / Q000187:drug effects; D015139:Blotting, Southern; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003300:Copper / Q000494:pharmacology; D004247:DNA / Q000187:drug effects* / Q000378:metabolism; D003956:Dialysis; D004791:Enzyme Inhibitors; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D007364:Intercalating Agents / Q000494:pharmacology; D019169:Jurkat Cells; D010957:Plasmids / Q000187:drug effects / Q000235:genetics; D011353:Prodigiosin / Q000494:pharmacology*; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors
chemical_list: D000903:Antibiotics, Antineoplastic; D004791:Enzyme Inhibitors; D007364:Intercalating Agents; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D003300:Copper; D004247:DNA; D011353:Prodigiosin