Tumor suppressor Fhit protein interacts with protoporphyrin IX in vitro and enhances the response of HeLa cells to photodynamic therapy.
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.
Zawacka-Pankau
Joanna
J
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
Kowalska
Agnieszka
A
Issaeva
Natalia
N
Burcza
Anna
A
Kwiek
Piotr
P
Bednarz
Natalia
N
Pramanik
Aladdin
A
Banecki
Bogdan
B
Podhajska
Anna J
AJ
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
D017766:Acid Anhydride Hydrolases; D009363:Neoplasm Proteins; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D000099170:Bis(5'-adenosyl)triphosphatase; C028025:protoporphyrin IX