title: Inhibition of PARP activity by PJ-34 leads to growth impairment and cell death associated with aberrant mitotic pattern and nucleolar actin accumulation in M14 melanoma cell line.
abstract: The capability of PARP activity inhibitors to prevent DNA damage recovery suggested the use of these drugs as chemo- and radio-sensitisers for cancer therapy. Our research, carried out on cultured human M14 melanoma cells, was aimed to examine if PJ-34, a potent PARP activity inhibitor of second generation, was per se able to affect the viability of these cancer cells without any DNA damaging agents. Using time-lapse videomicroscopy, we evidenced that 10 microM PJ-34 treatment induced severe mitotic defects leading to dramatic reduction of cell proliferation and to cell death. PJ-34 cytotoxic effect was further confirmed by analysis of cell viability and clonogenic assay. Absence of canonic apoptosis markers allowed us to exclude this kind of cell death. No single and/or double stranded DNA damage was evidenced. Immunofluorescence analysis showed an aberrant mitotic scenario in several cells and subsequent multinucleation suggesting an atypical way for cells to die: the mitotic catastrophe. The detection of aberrant accumulation of polymerised actin inside the nucleolus was noteworthy. Taken together, our results demonstrate that, targeting PARP activity by PJ-34, cancer cell survival is affected independently of DNA damage repair. Two findings are remarkable: (a) cisplatin concentration can be reduced by three quarters if it is followed by treatment with 10 microM PJ-34 for 24 h to obtain the same cytotoxic effect; (b) effects dependent on PJ-34 treatment are reversible. Our data suggest that, to reduce the harm done to non-tumour cells during chemotherapy with cisplatin, the latter could be coupled with PJ-34 treatment.
authors.affiliation: Department of Experimental Pathology and Oncology, University of Florence, Florence, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Chevanne
authors.forename: Michele
authors.initials: M
authors.lastname: Zampieri
authors.forename: Riccardo
authors.initials: R
authors.lastname: Caldini
authors.forename: Angela
authors.initials: A
authors.lastname: Rizzo
authors.forename: Fabio
authors.initials: F
authors.lastname: Ciccarone
authors.forename: Angela
authors.initials: A
authors.lastname: Catizone
authors.forename: Carmen
authors.initials: C
authors.lastname: D'Angelo
authors.forename: Tiziana
authors.initials: T
authors.lastname: Guastafierro
authors.forename: Anna
authors.initials: A
authors.lastname: Biroccio
authors.forename: Anna
authors.initials: A
authors.lastname: Reale
authors.forename: Gabriella
authors.initials: G
authors.lastname: Zupi
authors.forename: Paola
authors.initials: P
authors.lastname: Caiafa
mesh_terms: D000199:Actins / Q000378:metabolism*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D016923:Cell Death; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000187:drug effects* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D018715:Microscopy, Video; D008938:Mitosis / Q000187:drug effects*; D010616:Phenanthrenes / Q000494:pharmacology*; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D013997:Time Factors
chemical_list: D000199:Actins; D004791:Enzyme Inhibitors; C434926:N-(oxo-5,6-dihydrophenanthridin-2-yl)-N,N-dimethylacetamide hydrochloride; D010616:Phenanthrenes; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases; D002945:Cisplatin