title: Beta-lapachone-mediated apoptosis in human promyelocytic leukemia (HL-60) and human prostate cancer cells: a p53-independent response.
abstract: beta-Lapachone and certain of its derivatives directly bind and inhibit topoisomerase I (Topo I) DNA unwinding activity and form DNA-Topo I complexes, which are not resolvable by SDS-K+ assays. We show that beta-lapachone can induce apoptosis in certain cells, such as in human promyelocytic leukemia (HL-60) and human prostate cancer (DU-145, PC-3, and LNCaP) cells, as also described by Li et al. (Cancer Res., 55: 0000-0000, 1995). Characteristic 180-200-bp oligonucleosome DNA laddering and fragmented DNA-containing apoptotic cells via flow cytometry and morphological examinations were observed in 4 h in HL-60 cells after a 4-h, > or = 0.5 microM beta-lapachone exposure. HL-60 cells treated with camptothecin or topotecan resulted in greater apoptotic DNA laddering and apoptotic cell populations than comparable equitoxic concentrations of beta-lapachone, although beta-lapachone was a more effective Topo I inhibitor. beta-Lapachone treatment (4 h, 1-5 microM) resulted in a block at G0/G1, with decreases in S and G2/M phases and increases in apoptotic cell populations over time in HL-60 and three separate human prostate cancer (DU-145, PC-3, and LNCaP) cells. Similar treatments with topotecan or camptothecin (4 h, 1-5 microM) resulted in blockage of cells in S and apoptosis. Thus, beta-lapachone causes a block in G0/G1 of the cell cycle and induces apoptosis in cells before, or at early times during, DNA synthesis. These events are p53 independent, since PC-3 and HL-60 cells are null cells, LNCaP are wild-type, and DU-145 contain mutant p53, yet all undergo apoptosis after beta-lapachone treatment. Interestingly, beta-lapachone treatment of p53 wild type-containing prostate cancer cells (i.e., LNCaP) did not result in the induction of nuclear levels of p53 protein, as did camptothecin-treated cells. Like other Topo I inhibitors, beta-lapachone may induce apoptosis by locking Topo I onto DNA, blocking replication fork movement, and inducing apoptosis in a p53-independent fashion. beta-Lapachone and its derivatives, as well as other Topo I inhibitors, have potential clinical utility alone against human leukemia and prostate cancers.
authors.affiliation: Department of Human Oncology, School of Medicine, University of Wisconsin-Madison, Madison 53792, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Planchon
authors.forename: S
authors.initials: S
authors.lastname: Wuerzberger
authors.forename: B
authors.initials: B
authors.lastname: Frydman
authors.forename: D T
authors.initials: DT
authors.lastname: Witiak
authors.forename: P
authors.initials: P
authors.lastname: Hutson
authors.forename: D R
authors.initials: DR
authors.lastname: Church
authors.forename: G
authors.initials: G
authors.lastname: Wilding
authors.forename: D A
authors.initials: DA
authors.lastname: Boothman
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000473:pathology; D002166:Camptothecin / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology / Q000473:pathology*; D008297:Male; D009285:Naphthoquinones / Q000008:administration & dosage / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000473:pathology*; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D013997:Time Factors; D059004:Topoisomerase I Inhibitors; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay
chemical_list: D009285:Naphthoquinones; D059004:Topoisomerase I Inhibitors; C014638:beta-lapachone; D002166:Camptothecin; D004121:Dimethyl Sulfoxide