title: Prostate cancer gene therapy: comparison of adenovirus-mediated expression of interleukin 12 with interleukin 12 plus B7-1 for in situ gene therapy and gene-modified, cell-based vaccines.
abstract: We have documented previously that adenovirus-mediated interleukin 12 (IL-12) gene therapy is effective for orthotopic tumor control and suppression of pre-established metastases in a preclinical prostate cancer model (Y. Nasu et al., Gene Ther., 6: 338-349, 1999). In this report, we directly compare the effectiveness of an adenovirus that expresses both IL-12 and the costimulatory molecule B7-1 (AdmIL12/B7) with one that expresses IL-12 alone (AdmIL-12) using the poorly immunogenic RM-9 orthotopic murine model of prostate cancer. We document AdmIL-12/B7-mediated secretion of IL-12 and increased surface expression of B7-1 in infected RM-9 tumor cells. A significant reduction in orthotopic tumor size and increased survival was demonstrated in mice treated with a single orthotopic injection of AdmIL-12/B7 compared with AdmIL-12 or controls. Six of 19 animals treated with AdmIL-12/B7 survived long term with apparent eradication of the primary tumor in contrast to one of 38 animals in the AdmIL-12-treated group. Orthotopic treatment of tumors with both vectors led to an infiltration of both CD4+ and CD8+ immunoreactive cells, with AdmIL-12/B7 treatment having a more prolonged infiltration of CD8+ cells. AdmIL-12/B7 was also more effective than AdmIL-12 or controls at suppression of pre-established metastases. We further developed a vaccine model based on s.c. injection of infected, irradiated RM-9 cells and found that both AdmIL-12 and AdmIL-12/B7 are effective at suppressing the development and growth of challenge orthotopic tumors using this protocol.
authors.affiliation: Scott Department of Urology Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: Hull
authors.forename: M A
authors.initials: MA
authors.lastname: Mccurdy
authors.forename: Y
authors.initials: Y
authors.lastname: Nasu
authors.forename: C H
authors.initials: CH
authors.lastname: Bangma
authors.forename: G
authors.initials: G
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Shimura
authors.forename: H M
authors.initials: HM
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Albani
authors.forename: S
authors.initials: S
authors.lastname: Ebara
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: T L
authors.initials: TL
authors.lastname: Timme
authors.forename: T C
authors.initials: TC
authors.lastname: Thompson
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D018122:B7-1 Antigen / Q000235:genetics*; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens / Q000378:metabolism; D019496:Cancer Vaccines; D005434:Flow Cytometry; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D018664:Interleukin-12 / Q000235:genetics*; D007700:Kinetics; D008175:Lung Neoplasms / Q000628:therapy; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D011471:Prostatic Neoplasms / Q000628:therapy*; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D018122:B7-1 Antigen; D015704:CD4 Antigens; D016827:CD8 Antigens; D019496:Cancer Vaccines; D018664:Interleukin-12