title: Enhanced CRAd activity using enhancer motifs driven by a nucleosome positioning sequence.
abstract: Cancer development involves changes driven by the epigenetic machinery, including nucleosome positioning. Recently, the concept that adenoviral replication may be driven by tumor specific promoters (TSPs) gained support, and several conditionally replicative adenoviruses (CRAd) exhibited therapeutic efficacy in clinical trials. Here, we show for the first time that placing a nucleosome positioning sequence (NPS) upstream of a TSP combined with Wnt-responsive motifs (pART enhancer) enhanced the TSP transcriptional activity and increased the lytic activity of a CRAd. pART enhanced the transcriptional activity of the gastrointestinal cancer (GIC)-specific REG1A promoter (REG1A-pr); moreover, pART also increased the in vitro lytic activity of a CRAd whose replication was driven by REG1A-Pr. The pART enhancer effect in vitro and in vivo was strictly dependent on the presence of the NPS. Indeed, deletion of the NPS was strongly deleterious for the in vivo antitumor efficacy of the CRAd on orthotopically established pancreatic xenografts. pART also enhanced the specific activity of other heterologous promoters; moreover, the NPS was also able to enhance the responsiveness of hypoxia- and NFκB-response elements. We conclude that NPS could be useful for gene therapy approaches in cancer as well as other diseases.
authors.affiliation: Centro de Investigaciones Biomédicas and FONDAP Center for Genome Regulation, Universidad Andres Bello, Santiago, Chile.
authors.forename: Soraya
authors.initials: S
authors.lastname: Bravo
authors.forename: Felipe
authors.initials: F
authors.lastname: Núñez
authors.forename: Fernando
authors.initials: F
authors.lastname: Cruzat
authors.forename: Eduardo G
authors.initials: EG
authors.lastname: Cafferata
authors.forename: Giancarlo V
authors.initials: GV
authors.lastname: De Ferrari
authors.forename: Martín
authors.initials: M
authors.lastname: Montecino
authors.forename: Osvaldo L
authors.initials: OL
authors.lastname: Podhajcer
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D015316:Genetic Therapy; D019073:HT29 Cells; D006801:Humans; D008297:Male; D008819:Mice, Nude; D009707:Nucleosomes / Q000235:genetics*; D050130:Oncolytic Virotherapy; D010190:Pancreatic Neoplasms / Q000628:therapy; D011401:Promoter Regions, Genetic / Q000235:genetics; D014779:Virus Replication / Q000235:genetics / Q000502:physiology; D023041:Xenograft Model Antitumor Assays
chemical_list: D009707:Nucleosomes