title: Protolichesterinic acid enhances doxorubicin-induced apoptosis in HeLa cells in vitro.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of protolichesterinic acid, a lichen secondary metabolite, on anti-proliferative activity of doxorubicin in three human cancer cell lines, HeLa, SH-SY5Y and K562 cells.
  
  
  METHODS
  The data obtained from MTT assays, performed on cells treated with protolichesterinic acid and doxorubicin alone and in combination, were analysed by the median-effect method as proposed by Chou and Talalay and the Bliss independence model. Apoptosis rate was evaluated by fluorescence microscopy, caspase-3, 8 and 9 activities were detected by spectrofluorimetric analysis and protein expression of Bim, Bid, Bax and Mcl-2 was analysed by Western blotting. The interaction of protolichesterinic acid with thioesterase domain of human fatty acid synthase (hFAS) was investigated by a molecular docking study.
  
  
  RESULTS
  The in vitro activity of doxorubicin against HeLa cancer cell line, but not against SH-SY5Y and K562 cells, was synergically increased by protolichesterinic acid. The increased cytotoxicity caused by protolichesterinic acid in HeLa cells was due to a pro-apoptotic effect and was associated to caspase-3, 8 and 9 activation. The simultaneous treatment for 24h with protolichesterinic acid plus doxorubicin caused an increase of Bim protein expression and the appearance of cleaved form of Bid protein. The molecular modelling analysis showed that protolichesterinic acid seemed to behave as a competitive inhibitor of hFAS.
  
  
  CONCLUSIONS
  These results suggest that protolichesterinic acid could be envisaged as an useful tool against certain types of tumor cells in combination with anticancer drugs.
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy. Electronic address: fabrizia.brisdelli@cc.univaq.it.
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Brisdelli
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Perilli
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Doriana
authors.initials: D
authors.lastname: Sellitri
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Bellio
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Argante
authors.initials: A
authors.lastname: Bozzi
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Amicosante
authors.affiliation: Department of Environmental Biology, University Sapienza, Rome, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Nicoletti
authors.affiliation: Department of Chemistry, Universidad Federico Santa Maria, Casilla 110-V, Valparaiso, Chile.
authors.forename: Marisa
authors.initials: M
authors.lastname: Piovano
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Celenza
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D004317:Doxorubicin / Q000494:pharmacology*; D004357:Drug Synergism; D006367:HeLa Cells; D006801:Humans; D062105:Molecular Docking Simulation
chemical_list: D000903:Antibiotics, Antineoplastic; C095781:protolichesterinic acid; D004317:Doxorubicin; D015107:4-Butyrolactone
keywords: Apoptosis; Doxorubicin; HeLa cells; Protolichesterinic acid