title: Artelastin is a cytotoxic prenylated flavone that disturbs microtubules and interferes with DNA replication in MCF-7 human breast cancer cells.
abstract: Artelastin, a novel prenylated flavone, previously isolated from the wood bark of Artocarpus elasticus, was evaluated for its capacity to inhibit the growth of fifty-two human tumor cell lines, representing nine different tumor types. A pronounced dose-dependent growth inhibitory effect was detected in all the cell lines, with GI50 values ranging from 0.8-20.8 microM. Studies to elucidate the basis of the growth inhibitory activity of artelastin were performed in the MCF-7 human breast cancer cell line (GI50 = 6.0 microM). We show that artelastin exerts a biphasic effect in the DNA synthesis of MCF-7 cells, a stimulatory effect at low concentrations (below GI50) for short times of exposition (6 h and 24 h), and an inhibitory effect at high concentrations (above GI50). Remarkably, treated cells that have DNA synthesis affected could be viable and metabolically active. Furthermore, artelastin acts as a cytotoxic rather than a cytostatic compound. Massive cytoplasmatic vacuoles were detected in cells after artelastin treatment. Together with these morphological alterations, cells show the presence of abnormal nuclear morphologies, and occasionally nuclear condensation, which were identified as apoptotic by TUNEL assay. Moreover, artelastin was shown to disturb the microtubule network while no effect was observed on the kinetochores. Flow cytometry analysis of cells treated with artelastin reveal an accumulation in S phase that interferes with the cell cycle progression. Additionally, according to BrdU patterns, studies with synchronized cells at G0 and at G1/S transition also suggest that artelastin delays DNA replication since progression of cells trough S-phase is perturbed.
authors.affiliation: Centro de Estudos de Química Orgânica, Fitoquímica e Farmacologia da Universidade do Porto, Portugal.
authors.forename: Madalena
authors.initials: M
authors.lastname: Pedro
authors.forename: Maria Manuel
authors.initials: MM
authors.lastname: Ferreira
authors.forename: Honorina
authors.initials: H
authors.lastname: Cidade
authors.forename: Anake
authors.initials: A
authors.lastname: Kijjoa
authors.forename: Elsa
authors.initials: E
authors.lastname: Bronze-da-Rocha
authors.forename: Maria São José
authors.initials: MS
authors.lastname: Nascimento
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape; D002470:Cell Survival / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005260:Female; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008870:Microtubules / Q000187:drug effects*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D005419:Flavonoids; D010936:Plant Extracts; C477276:artelastin