Francesco Marampon1, Silvia Codenotti2, Francesca Megiorni3, Andrea Del Fattore4, Simona Camero3, Giovanni Luca Gravina5, Claudio Festuccia5, Daniela Musio6, Francesca De Felice6, Valerio Nardone7, Anna Natalizia Santoro8, Carlo Dominici6, Alessandro Fanzani2, Luigi Pirtoli8,9,10,11,12,13, Antonella Fioravanti14, Vincenzo Tombolini6, Sara Cheleschi13, Paolo Tini9,10,12,14. 1. Department of Radiotherapy, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy. f.marampon@gmail.com. 2. Division of Biotechnology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy. 3. Department of Pediatrics, "Sapienza" University of Rome, Rome, Italy. 4. Multi-Factorial Disease and Complex Phenotype Research Area, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo 15, 00146, Rome, Italy. 5. Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, Coppito 2, 67100, L'Aquila, Italy. 6. Department of Radiotherapy, Policlinico Umberto I, "Sapienza" University of Rome, Rome, Italy. 7. Unit of Radiation Therapy, Ospedale del Mare, Naples, Italy. 8. Azienda Ospedaliera Universitaria Senese, Siena, Italy. 9. Unit of Radiation Oncology, Azienda Ospedaliera Universitaria Senese, Siena, Italy. 10. Istituto Toscano Tumori, Florence, Italy. 11. Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy. 12. Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, USA. 13. Department of Medicine, Surgery and Neuroscience, Rheumatology Unit, University of Siena, Policlinico Le Scotte, Siena, Italy. 14. Sbarro Health Research Organization, Temple University, Philadelphia, PA, USA.
Abstract
PURPOSE: Tumor cells generally exhibit higher levels of reactive oxygen species (ROS), however, when stressed, tumor cells can undergo a process of 'Redox Resetting' to acquire a new redox balance with stronger antioxidant systems that enable cancer cells to become resistant to radiation therapy (RT). Here, we describe how RT affects the oxidant/antioxidant balance in human embryonal (RD) and alveolar (RH30) rhabdomyosarcoma (RMS) cell lines, investigating on the molecular mechanisms involved. METHODS: Radiations were delivered using an x-6 MV photon linear accelerator and their effects were assessed by vitality and clonogenic assays. The expression of specific antioxidant-enzymes, such as Superoxide Dismutases (SODs), Catalase (CAT) and Glutathione Peroxidases 4 (GPx4), miRNAs (miR-22, -126, -210, -375, -146a, -34a) and the transcription factor NRF2 was analyzed by quantitative polymerase chain reaction (q-PCR) and western blotting. RNA interference experiments were performed to evaluate the role of NRF2. RESULTS: Doses of RT higher than 2 Gy significantly affected RMS clonogenic ability by increasing ROS production. RMS rapidly and efficiently brought back ROS levels by up-regulating the gene expression of antioxidant enzymes, miRNAs as well as of NRF2. Silencing of NRF2 restrained the RMS ability to counteract RT-induced ROS accumulation, antioxidant enzyme and miRNA expression and was able to increase the abundance of γ-H2AX, a biomarker of DNA damage, in RT-treated cells. CONCLUSIONS: Taken together, our data suggest the strategic role of oxidant/antioxidant balance in restraining the therapeutic efficiency of RT in RMS treatment and identify NRF2 as a new potential molecular target whose inhibition might represent a novel radiosensitizing therapeutic strategy for RMS clinical management.
PURPOSE:Tumor cells generally exhibit higher levels of reactive oxygen species (ROS), however, when stressed, tumor cells can undergo a process of 'Redox Resetting' to acquire a new redox balance with stronger antioxidant systems that enable cancer cells to become resistant to radiation therapy (RT). Here, we describe how RT affects the oxidant/antioxidant balance in human embryonal (RD) and alveolar (RH30) rhabdomyosarcoma (RMS) cell lines, investigating on the molecular mechanisms involved. METHODS:Radiations were delivered using an x-6 MV photon linear accelerator and their effects were assessed by vitality and clonogenic assays. The expression of specific antioxidant-enzymes, such as Superoxide Dismutases (SODs), Catalase (CAT) and Glutathione Peroxidases 4 (GPx4), miRNAs (miR-22, -126, -210, -375, -146a, -34a) and the transcription factor NRF2 was analyzed by quantitative polymerase chain reaction (q-PCR) and western blotting. RNA interference experiments were performed to evaluate the role of NRF2. RESULTS: Doses of RT higher than 2 Gy significantly affected RMS clonogenic ability by increasing ROS production. RMS rapidly and efficiently brought back ROS levels by up-regulating the gene expression of antioxidant enzymes, miRNAs as well as of NRF2. Silencing of NRF2 restrained the RMS ability to counteract RT-induced ROS accumulation, antioxidant enzyme and miRNA expression and was able to increase the abundance of γ-H2AX, a biomarker of DNA damage, in RT-treated cells. CONCLUSIONS: Taken together, our data suggest the strategic role of oxidant/antioxidant balance in restraining the therapeutic efficiency of RT in RMS treatment and identify NRF2 as a new potential molecular target whose inhibition might represent a novel radiosensitizing therapeutic strategy for RMS clinical management.
Authors: Isabelle Bairati; François Meyer; Michel Gélinas; André Fortin; Abdenour Nabid; François Brochet; Jean-Philippe Mercier; Bernard Têtu; François Harel; Belkacem Abdous; Eric Vigneault; Sylvie Vass; Pierre Del Vecchio; Jean Roy Journal: J Clin Oncol Date: 2005-07-18 Impact factor: 44.544
Authors: David Llobet; Nuria Eritja; Mario Encinas; Anabel Sorolla; Andree Yeramian; Joan Antoni Schoenenberger; Antonio Llombart-Cussac; Rosa M Marti; Xavier Matias-Guiu; Xavier Dolcet Journal: Anticancer Drugs Date: 2008-02 Impact factor: 2.248