Abstract
Rhabdomyosarcomas are a major cause of cancer death in children, described with MYCN amplification and, in the alveolar subtype, transcription driven by the PAX3-FOXO1 fusion protein. Our aim was to determine the prevalence of N-Myc protein expression and the potential therapeutic effects of reducing expression in rhabdomyosarcomas, including use of an antigene strategy that inhibits transcription. Protein expression was assessed by immunohistochemistry. MYCN expression was reduced in representative cell lines by RNA interference and an antigene peptide nucleic acid (PNA) oligonucleotide conjugated to a nuclear localization signal peptide. Associated gene expression changes, cell viability, and apoptosis were analyzed in vitro. As a paradigm for antigene therapy, the effects of systemic treatment of mice with rhabdomyosarcoma cell line xenografts were determined. High N-Myc levels were significantly associated with genomic amplification, presence of the PAX3/7-FOXO1 fusion genes, and proliferative capacity. Sustained reduction of N-Myc levels in all rhabdomyosarcoma cell lines that express the protein decreased cell proliferation and increased apoptosis. Positive feedback was shown to regulate PAX3-FOXO1 and N-Myc levels in the alveolar subtype that critically decrease PAX3-FOXO1 levels on reducing N-Myc. Pharmacologic systemic administration of the antigene PNA can eliminate alveolar rhabdomyosarcoma xenografts in mice, without relapse or toxicity. N-Myc, with its restricted expression in non-fetal tissues, is a therapeutic target to treat rhabdomyosarcomas, and blocking gene transcription using antigene oligonucleotide strategies has therapeutic potential in the treatment of cancer and other diseases that has not been previously realized in vivo.
Highlights
The Myc-family of transcription factors are involved in many critical cellular processes including cell proliferation and apoptosis and they are implicated in the development and progression of tumors [1]
High N-Myc levels were significantly associated with genomic amplification, presence of the PAX3/7-FOXO1 fusion genes, and proliferative capacity
N-Myc, with its restricted expression in non-fetal tissues, is a therapeutic target to treat rhabdomyosarcomas, and blocking gene transcription using antigene oligonucleotide strategies has therapeutic potential in the treatment of cancer and other diseases that has not been previously realized in vivo
Summary
The Myc-family of transcription factors are involved in many critical cellular processes including cell proliferation and apoptosis and they are implicated in the development and progression of tumors [1]. MYCN gene amplification is Authors' Affiliations: Departments of 1Pediatric Hematology and Oncology and 2Pharmacology, University of Bologna; 3Department of Nuclear Medicine, University of Bologna, S. Orsola Hospital, Bologna, Italy; 4Sarcoma Molecular Pathology Team, Divisions of Molecular Pathology and Cancer Therapeutics and 5Pediatric Oncology, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 6Department of Human Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands; 7Department of Organic and Industrial Chemistry, University of Parma, Parma, Italy; 8Kiel Pediatric Tumor Registry, Department of Pediatric Pathology, University of Kiel, Kiel, Germany; 9Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, Chester Beatty Laboratories; and 10Department of Histopathology, Royal Marsden NHS Trust, London, United Kingdom. Most widely known for its association with poor outcome in neuroblastomas [2], other pediatric tumors including rhabdomyosarcomas (RMS) have been described with MYCN amplification [3,4,5]. The. Gene expression data have been deposited in the GEO database, accession number GSE7959.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
