I Postiglione1, F Barra1, S M Aloj1, G Palumbo1. 1. Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
Abstract
OBJECTIVES: In spite of high sensitivity of A549 cells (p53(+/+) ) to lethal effects of photodynamic therapy with 5-aminolaevulinic acid (5-ALA/PDT), DNA damage was observed only in H1299 cells (p53(-/-) ), suggesting that p53 may exert a protective effect. Studies on human colon adenocarcinoma cell lines HCT-116, and their cognate knockouts for p53, were not entirely consistent with the assumption above. Exploring alternative explanations for such conflicting behaviour, we observed that expression of the ATP-binding cassette G2 (ABCG2), a regulator of cell component efflux, had important effects on PDT-generated DNA injury in PC3 cells (prostate) which are p53(-/-) and positive for ABCG2. Addition of an ABCG2 inhibitor in ABCG2 positive A549 (p53(+/+) ) and PC3 (p53(-/-) ) cells eliminated resistance to DNA damage. MATERIALS AND METHODS: All cell lines investigated were incubated with 5-ALA and irradiated. Effects of PDT were evaluated assessing residual cell viability, cell-cycle profiles, PpIX localization, comet assay and Western blotting. Identical measurements were made in the presence of ABCG2 inhibitor, in cells expressing the transporter. RESULTS: Our data show that cell aptitude to defend its DNA from PDT-induced injury was mainly ruled by ABCG2 expression. These findings, while providing helpful information in predicting effectiveness of 5-ALA/PDT, may indicate a way to shift PDT from a palliative to a more effective approach in anti-cancer therapy.
OBJECTIVES: In spite of high sensitivity of A549 cells (p53(+/+) ) to lethal effects of photodynamic therapy with 5-aminolaevulinic acid (5-ALA/PDT), DNA damage was observed only in H1299 cells (p53(-/-) ), suggesting that p53 may exert a protective effect. Studies on humancolon adenocarcinoma cell lines HCT-116, and their cognate knockouts for p53, were not entirely consistent with the assumption above. Exploring alternative explanations for such conflicting behaviour, we observed that expression of the ATP-binding cassette G2 (ABCG2), a regulator of cell component efflux, had important effects on PDT-generated DNA injury in PC3 cells (prostate) which are p53(-/-) and positive for ABCG2. Addition of an ABCG2 inhibitor in ABCG2 positive A549 (p53(+/+) ) and PC3 (p53(-/-) ) cells eliminated resistance to DNA damage. MATERIALS AND METHODS: All cell lines investigated were incubated with 5-ALA and irradiated. Effects of PDT were evaluated assessing residual cell viability, cell-cycle profiles, PpIX localization, comet assay and Western blotting. Identical measurements were made in the presence of ABCG2 inhibitor, in cells expressing the transporter. RESULTS: Our data show that cell aptitude to defend its DNA from PDT-induced injury was mainly ruled by ABCG2 expression. These findings, while providing helpful information in predicting effectiveness of 5-ALA/PDT, may indicate a way to shift PDT from a palliative to a more effective approach in anti-cancer therapy.
Authors: P Uehlinger; M Zellweger; G Wagnières; L Juillerat-Jeanneret; H van den Bergh; N Lange Journal: J Photochem Photobiol B Date: 2000-01 Impact factor: 6.252
Authors: Johan W Jonker; Marije Buitelaar; Els Wagenaar; Martin A Van Der Valk; George L Scheffer; Rik J Scheper; Torsten Plosch; Folkert Kuipers; Ronald P J Oude Elferink; Hilde Rosing; Jos H Beijnen; Alfred H Schinkel Journal: Proc Natl Acad Sci U S A Date: 2002-11-12 Impact factor: 11.205
Authors: Laurent Candeil; Isabelle Gourdier; Delphine Peyron; Nadia Vezzio; Virginie Copois; Frederic Bibeau; Beatrice Orsetti; George L Scheffer; Marc Ychou; Qasim A Khan; Yves Pommier; Bernard Pau; Pierre Martineau; Maguy Del Rio Journal: Int J Cancer Date: 2004-05-10 Impact factor: 7.396
Authors: Partha Krishnamurthy; Douglas D Ross; Takeo Nakanishi; Kim Bailey-Dell; Sheng Zhou; Kelly E Mercer; Balazs Sarkadi; Brian P Sorrentino; John D Schuetz Journal: J Biol Chem Date: 2004-03-24 Impact factor: 5.157