title: Curcumin-induced mitotic arrest is characterized by spindle abnormalities, defects in chromosomal congression and DNA damage.
abstract: The chemopreventive agent curcumin has anti-proliferative effects in many tumour types, but characterization of cell cycle arrest, particularly with physiologically relevant concentrations, is still incomplete. Following oral ingestion, the highest concentrations of curcumin are achievable in the gut. Although it has been established that curcumin induces arrest at the G(2)/M stage of the cell cycle in colorectal cancer lines, it is not clear whether arrest occurs at the G(2)/M transition or in mitosis. To elucidate the precise stage of arrest, we performed a direct comparison of the levels of curcumin-induced G(2)/M boundary and mitotic arrest in eight colorectal cancer lines (Caco-2, DLD-1, HCA-7, HCT116p53+/+, HCT116p53(-)/(-), HCT116p21(-)/(-), HT-29 and SW480). Flow cytometry confirmed that these lines underwent G(2)/M arrest following treatment for 12h with clinically relevant concentrations of curcumin (5-10 μM). In all eight lines, the majority of this arrest occurred at the G(2)/M transition, with a proportion of cells arresting in mitosis. Examination of the mitotic index using fluorescence microscopy showed that the HCT116 and Caco-2 lines exhibited the highest levels of curcumin-induced mitotic arrest. Image analysis revealed impaired mitotic progression in all lines, exemplified by mitotic spindle abnormalities and defects in chromosomal congression. Pre-treatment with inhibitors of the DNA damage signalling pathway abrogated curcumin-induced mitotic arrest, but had little effect at the G(2)/M boundary. Moreover, pH2A.X staining seen in mitotic, but not interphase, cells suggests that this aberrant mitosis results in DNA damage.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester LE1 7RH, UK.
authors.forename: Louise M
authors.initials: LM
authors.lastname: Blakemore
authors.forename: Christoph
authors.initials: C
authors.lastname: Boes
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cordell
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Manson
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D064127:Aurora Kinases; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D020090:Chromosome Segregation / Q000187:drug effects*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D003474:Curcumin / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D008938:Mitosis / Q000187:drug effects*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D008941:Spindle Apparatus / Q000187:drug effects*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D003474:Curcumin