title: Transformation by retroviral vectors of bone marrow-derived mesenchymal cells induces mitochondria-dependent cAMP-sensitive reactive oxygen species production.
abstract: Retroviral vectors are used in human gene therapy trials to stably introduce therapeutic genes in the genome of patients' cells. Their applicability, however, is frustrated by the limited viability of transformed cells and/or by risks linked to selection of oncogene-mutated clones. The reasons for these drawbacks are not yet completely understood. In this study, we show that LXSN-NeoR gene/interleukin-7-engineered mesenchymal stromal cells exhibited a marked enhancement of reactive oxygen species production compared with untransfected cells. This effect resulted to be independent on the product of the gene carried by the retroviral vehicle as it was reproducible in cells transfected with the empty vector alone. Stable transfection of mesenchymal stromal cells with the different retroviral vectors pBabe-puro and PINCO-puro and the lentiviral vector pSico PGK-puro caused similar redox imbalance, unveiling a phenomenon of more general impact. The enhanced production of reactive oxygen species over the basal level was attributable to mitochondrial dysfunction and brought back to altered activity of the NADH-CoQ oxidoreductase (complex I) of the respiratory chain. The oxidative stress in transfected mesenchymal stem cells was completely reversed by treatment with a cAMP analog, thus pointing to alteration in the protein kinase A-dependent signaling pathway of the host cell. Transfection of mesenchymal stromal cells with a PINCO-parental vector harboring the green fluorescent protein gene as selection marker in place of the puromycin-resistance gene resulted in no alteration of the redox phenotype. These novel findings provide insights and caveats to the applicability of cell- or gene-based therapies and indicate possible intervention to improve them. Disclosure of potential conflicts of interest is found at the end of this article.
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine, University of Foggia, Foggia, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Piccoli
authors.forename: Rosella
authors.initials: R
authors.lastname: Scrima
authors.forename: Maria
authors.initials: M
authors.lastname: Ripoli
authors.forename: Mauro
authors.initials: M
authors.lastname: Di Ianni
authors.forename: Beatrice
authors.initials: B
authors.lastname: Del Papa
authors.forename: Annamaria
authors.initials: A
authors.lastname: D'Aprile
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarato
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Martelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Servillo
authors.forename: Claudio
authors.initials: C
authors.lastname: Ligas
authors.forename: Domenico
authors.initials: D
authors.lastname: Boffoli
authors.forename: Antonio
authors.initials: A
authors.lastname: Tabilio
authors.forename: Nazzareno
authors.initials: N
authors.lastname: Capitanio
mesh_terms: D001854:Bone Marrow Cells / Q000166:cytology*; D002460:Cell Line; D019069:Cell Respiration / Q000502:physiology; D002472:Cell Transformation, Viral; D000242:Cyclic AMP / Q000378:metabolism* / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors / Q000502:physiology; D006801:Humans; D015851:Interleukin-7 / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D008648:Mesoderm / Q000166:cytology; D008928:Mitochondria / Q000502:physiology*; D008979:Moloney murine leukemia virus / Q000235:genetics; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017154:Stromal Cells / Q000166:cytology; D014161:Transduction, Genetic
chemical_list: D015851:Interleukin-7; D017382:Reactive Oxygen Species; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D042967:Electron Transport Complex I