title: Tumor suppressor Fhit protein interacts with protoporphyrin IX in vitro and enhances the response of HeLa cells to photodynamic therapy.
abstract: Fhit, the product of tumor suppressor fragile histidine triad (FHIT) gene, exhibits antitumor activity of still largely unknown cellular background. However, it is believed that Fhit-Ap(3)A or Fhit-AMP complex might act as a second class messenger in cellular signal transduction pathway involved in cell proliferation and apoptosis. We demonstrate here for the first time that the photosensitizer, protoporphyrin IX (which is a natural precursor of heme) binds to Fhit protein and its mutants in the active site in vitro. Furthermore, PpIX inhibits the enzymatic activity of Fhit. Simultaneously, PpIX shows lower binding capacity to mutant Fhit-H96N of highly reduced hydrolase activity. In cell-based assay PpIX induced HeLa cell death in Fhit and Fhit-H96N-dependent manner which was measured by means of MTT assay. Moreover, HeLa cells stably expressing Fhit or mutant Fhit-H96N were more susceptible to protoporphyrin IX-mediated photodynamic therapy (2J/cm(2)) than parental cells.
authors.affiliation: Department of Biotechnology, Division of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland. jzawacka@biotech.univ.gda.pl
authors.forename: Joanna
authors.initials: J
authors.lastname: Zawacka-Pankau
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kowalska
authors.forename: Natalia
authors.initials: N
authors.lastname: Issaeva
authors.forename: Anna
authors.initials: A
authors.lastname: Burcza
authors.forename: Piotr
authors.initials: P
authors.lastname: Kwiek
authors.forename: Natalia
authors.initials: N
authors.lastname: Bednarz
authors.forename: Aladdin
authors.initials: A
authors.lastname: Pramanik
authors.forename: Bogdan
authors.initials: B
authors.lastname: Banecki
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Podhajska
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002470:Cell Survival; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010778:Photochemotherapy; D017319:Photosensitizing Agents; D011485:Protein Binding / Q000235:genetics; D011524:Protoporphyrins / Q000378:metabolism* / Q000502:physiology; D015290:Second Messenger Systems; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D009363:Neoplasm Proteins; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D000099170:Bis(5'-adenosyl)triphosphatase; C028025:protoporphyrin IX