title: Cell cycle perturbations and apoptosis induced by isohomohalichondrin B (IHB), a natural marine compound.
abstract: Isohomohalichondrin B (IHB), a novel marine compound with anti-tumoral activity, extracted from the Lissodendorix sponge, inhibits GTP binding to tubulin, preventing microtubule assembly. Cell cycle perturbations and apoptosis induced by IHB were investigated on selected human cancer cell lines by using flow cytometric and biochemical techniques. Monoparameter flow cytometric analysis showed that 1 h IHB exposure caused a delayed progression through S-phase, a dramatic block in G2M phase of the cell cycle and the appearance of tetraploid cell population in LoVo, LoVo/DX, MOLT-4 and K562 cells. At 24 h after IHB exposure, the majority of cells blocked in G2M were in prophase as assessed by morphological analysis and by the fact that they expressed high levels of cyclin A/cdc2 and cyclin B1/cdc2. At 48 h, all cells were tetraploid as assessed by biparameter cyclin A/DNA and cyclin B1/DNA content analysis. Apoptotic death was detected in both leukaemic MOLT-4 and K562 cells, which express wild-type and mutated p53 respectively, when the cells were blocked in mitotic prophase. In conclusion, IHB is a novel potent anti-tumour drug that causes delayed S-phase progression, mitotic block, tetraploidy and apoptosis in cancer cell lines.
authors.affiliation: Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Bergamaschi
authors.forename: S
authors.initials: S
authors.lastname: Ronzoni
authors.forename: S
authors.initials: S
authors.lastname: Taverna
authors.forename: M
authors.initials: M
authors.lastname: Faretta
authors.forename: P
authors.initials: P
authors.lastname: De Feudis
authors.forename: G
authors.initials: G
authors.lastname: Faircloth
authors.forename: J
authors.initials: J
authors.lastname: Jimeno
authors.forename: E
authors.initials: E
authors.lastname: Erba
authors.forename: M
authors.initials: M
authors.lastname: D'Incalci
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D001973:Bromodeoxyuridine / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects* / Q000378:metabolism; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D020014:K562 Cells / Q000187:drug effects; D008938:Mitosis / Q000187:drug effects; D011714:Pyrans / Q000494:pharmacology*; D016196:S Phase / Q000187:drug effects / Q000235:genetics; D013141:Spiro Compounds / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D011714:Pyrans; D013141:Spiro Compounds; C099151:isohomohalichondrin B; D001973:Bromodeoxyuridine