title: Cyclophosphamide increases transgene expression mediated by an oncolytic adenovirus in glioma-bearing mice monitored by bioluminescence imaging.
abstract: Approaches to improve the oncolytic potency of replication-competent adenoviruses include the insertion of therapeutic transgenes into the viral genome. Little is known about the levels and duration of in vivo transgene expression by cells infected with such "armed" viruses. Using a tumor-selective adenovirus encoding firefly luciferase (AdDelta24CMV-Luc) we investigated these questions in an intracranial mouse model for malignant glioma. Luciferase expression was detected by bioluminescence imaging, and the effect of the immunosuppressive agent cyclophosphamide (CPA) on transgene expression was assessed. Intratumoral AdDelta24CMV-Luc injection led to a localized dose-dependent expression of luciferase. Surprisingly, this expression decreased rapidly during the course of 14 days. In contrast, mice injected with nonreplicating Ad.CMV-Luc demonstrated stable transgene expression. Treatment of mice with CPA in combination with AdDelta24CMV-Luc retarded the loss of transgene expression. Staining of mouse brains for inflammatory cells demonstrated decreased tumor infiltration by immune cells in CPA-treated mice. Moreover, in immunodeficient NOD/SCID mice loss of transgene expression was less rapid and not prevented by CPA treatment. Together, our data demonstrate that transgene expression and viral replication decrease rapidly after intratumoral injection of oncolytic adenovirus in mouse brains and that treatment with the immunomodulator CPA prolongs viral-mediated gene expression.
authors.affiliation: Department of Neurosurgery, VU University Medical Center, Amsterdam 1007 MB, The Netherlands. M.Lamfers@vumc.nl
authors.forename: Martine L M
authors.initials: ML
authors.lastname: Lamfers
authors.forename: Giulia
authors.initials: G
authors.lastname: Fulci
authors.forename: Davide
authors.initials: D
authors.lastname: Gianni
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kurozumi
authors.forename: Balveen
authors.initials: B
authors.lastname: Kaur
authors.forename: Sharif
authors.initials: S
authors.lastname: Moeniralm
authors.forename: Yoshinaga
authors.initials: Y
authors.lastname: Saeki
authors.forename: Jan E
authors.initials: JE
authors.lastname: Carette
authors.forename: Ralph
authors.initials: R
authors.lastname: Weissleder
authors.forename: W Peter
authors.initials: WP
authors.lastname: Vandertop
authors.forename: Victor W
authors.initials: VW
authors.lastname: van Beusechem
authors.forename: Clemens M F
authors.initials: CM
authors.lastname: Dirven
authors.forename: E Antonio
authors.initials: EA
authors.lastname: Chiocca
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D005910:Glioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D017493:Leukocyte Common Antigens / Q000032:analysis; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D008822:Mice, Transgenic; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D050504:Oncolytic Viruses / Q000235:genetics; D019076:Transgenes / Q000235:genetics*; D014183:Transplantation, Heterologous; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018906:Antineoplastic Agents, Alkylating; D003520:Cyclophosphamide; D017493:Leukocyte Common Antigens; D008156:Luciferases; C067980:CD68 antigen, human; D000097382:CD68 Molecule