Topoisomerase Inhibitors Increase Episomal DNA Expression by Inducing the Integration of Episomal DNA in Hepatic Cells
Andoni Gómez-Moreno,
Enara San Sebastian,
Jennifer Moya,
Pilar Gomollón-Zueco,
Sergio Isola,
África Vales,
Gloria González-Aseguinolaza,
Carmen Unzu,
Urtzi Garaigorta
Affiliations
Andoni Gómez-Moreno
Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
Enara San Sebastian
Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
Jennifer Moya
Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
Pilar Gomollón-Zueco
Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
Sergio Isola
DNA & RNA Medicine Division, CIMA, Universidad de Navarra, Avda Pio XII, 55, 31008 Pamplona, Spain
África Vales
DNA & RNA Medicine Division, CIMA, Universidad de Navarra, Avda Pio XII, 55, 31008 Pamplona, Spain
Gloria González-Aseguinolaza
DNA & RNA Medicine Division, CIMA, Universidad de Navarra, Avda Pio XII, 55, 31008 Pamplona, Spain
Carmen Unzu
DNA & RNA Medicine Division, CIMA, Universidad de Navarra, Avda Pio XII, 55, 31008 Pamplona, Spain
Urtzi Garaigorta
Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
Gene therapy is a promising strategy to treat and cure most inherited metabolic liver disorders. Viral vectors such as those based on adeno-associated viruses (AAVs) and lentiviruses (LVs) are used as vehicles to deliver functional genes to affected hepatocytes. Adverse events associated with the use of high vector doses have motivated the use of small molecules as adjuvants to reduce the dose. In this study, we showed that a one-hour treatment with topoisomerase inhibitors (camptothecin and etoposide) prior to viral transduction is enough to increase AAV and LV reporter expression in non-dividing hepatic cells in culture. Topoisomerase inhibitors increased both integration-competent (ICLV) and integration-deficient (IDLV) LV-derived expression, with a much stronger increase in the IDLV transduction system. In agreement with that, topoisomerase inhibitors increased viral genome integration in both strains, with a greater impact on the IDLV strain, supporting the idea that topoisomerase inhibitors increased episomal DNA integration, especially when viral integrase activity is abolished. These effects correlated with an increase in the DNA damage response produced by the treatments. Our study highlights the need to monitor DNA damage and undesired integration of viral episomal DNAs into the host genome when studying chemical compounds that increase viral transduction.