title: Transmissibility of murine stem cell virus-based retroviral vectors carrying both interleukin-12 cDNAs and a third gene: implications for immune gene therapy.
abstract: The combination of immunotherapy with conventional treatments such as radio- and chemotherapy may be necessary to eradicate minimal residual disease. Interleukin 12 (IL-12) is a heterodimeric cytokine composed of two subunits, p40 and p35. Coordinate expression of the IL-12 p40 and p35 genes in several solid tumor models has been found to induce strong and specific antitumor immune responses. In the interest of obtaining high level IL-12 expression in leukemia/lymphoma cells for use as vaccines in cancer immunotherapy, we evaluated three IL-12 retroviral vector designs based on the murine stem cell virus (MSCV) vector which efficiently transduces functional genes into normal hematopoietic cells. MSCVpac-mlL-12 and MIPV-mIL-12 contain an encephalomyocarditis virus internal ribosome entry site for internal translation of bicistronic mRNA transcripts, while MDCVpac-mIL-12 carries an expression cassette in the U3 region of the 3' long terminal repeat. We found that the MSCVpac-mIL-12 vector directed robust expression of both p40 and p35 genes in several murine tumor cell lines of hematopoietic origin, including a T-cell lymphoma, a B-cell lymphoma, and a plasmacytoma/myeloma. In contrast, genomic instability or promoter interference hampered p40 gene expression in cells transduced with the MIPV-mIL-12 and MDCVpac-mIL-12 vectors, respectively. These findings provide the basis for the design of IL-12 retroviral vectors for the treatment of hematologic malignancies in humans.
authors.affiliation: Oncology Gene Therapy Program, Toronto Hospital, Ontario, Canada.
authors.forename: F H
authors.initials: FH
authors.lastname: Lieu
authors.forename: T S
authors.initials: TS
authors.lastname: Hawley
authors.forename: A Z
authors.initials: AZ
authors.lastname: Fong
authors.forename: R G
authors.initials: RG
authors.lastname: Hawley
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D000818:Animals; D005069:Evaluation Studies as Topic; D018014:Gene Transfer Techniques; D005796:Genes; D015316:Genetic Therapy; D005822:Genetic Vectors; D006412:Hematopoietic Stem Cells; D018664:Interleukin-12 / Q000235:genetics* / Q000276:immunology / Q000627:therapeutic use; D016906:Interleukin-9; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000628:therapy; D016399:Lymphoma, T-Cell / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D012190:Retroviridae / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D016906:Interleukin-9; D018664:Interleukin-12; D000123:Acetyltransferases; C045336:puromycin N-acetyltransferase