title: In vitro and in vivo characteristics of human squamous cell carcinoma of the head and neck cells engineered to secrete interleukin-2.
abstract: Two human squamous cell carcinoma of the head and neck (SCCHN) cell lines, PCI-13 and PCI-52, were transduced with the retroviral construct containing human interleukin-2 (IL-2) cDNA and selected for neomycin resistance in G418 medium. Stably transduced SCCHN cells produced and secreted IL-2, which was shown to have biologic activity in a bioassay, using an IL-2-dependent CTLL-2 cell line. By immunohistochemistry, IL-2 gene-transduced PCI-13 cells were strongly positive for IL-2, and by flow cytometry showed both cell surface and intracytoplasmic expression of IL-2 protein. Expression of IL-2 mRNA was measured by quantitative RT-PCR and found to be considerably increased in transduced SCCHN relative to that in parental cells. There was no difference in expression of IL-2R between the parental and IL-2 gene-transduced cells. In vitro proliferation of IL-2 gene-transduced tumor cells was consistently more rapid than that of parental cells. Sensitivity of the parental and IL-2 gene-transduced targets to lysis or apoptosis mediated by purified human natural killer (NK) cells or IL-2-activated NK (A-NK) cells was comparable as measured in 4-hour 51Cr-release and 1-hour [3H]thymidine-release assays, respectively. However, transduced cells were significantly more sensitive than parental cells to these effectors in 24-hour MTT assays, most likely due to IL-2 production by the transduced targets. PCI-52 cells selected for in vivo experiments formed large subcutaneous tumors in immunosuppressed nude mice. Tumors established by subcutaneous injections of 1 x 10(7) IL-2 gene-transduced cells regressed completely by day 25, while those formed by parental or LacZ gene-transduced tumor cells grew progressively. Tumor regression was mediated by numerous mononuclear cells, identified as murine NK cells and macrophages by immunohistochemistry, which accumulated around the IL-2-secreting, but not parental, tumors within 5-6 days after tumor cell injections. Thus, IL-2 gene-transduced SCCHN cells produce functional IL-2 in vivo in amounts sufficient to support the recruitment to the tumor site and antitumor activity of cytotoxic effector cells. IL-2-secreting SCCHN cells may be a useful component of vaccines designed to induce and sustain effector cell activation at the tumor site.
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pennsylvania, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nagashima
authors.forename: T E
authors.initials: TE
authors.lastname: Reichert
authors.forename: Y
authors.initials: Y
authors.lastname: Kashii
authors.forename: Y
authors.initials: Y
authors.lastname: Suminami
authors.forename: K
authors.initials: K
authors.lastname: Chikamatsu
authors.forename: T L
authors.initials: TL
authors.lastname: Whiteside
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000276:immunology* / Q000473:pathology* / Q000628:therapy; D002455:Cell Division; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D006258:Head and Neck Neoplasms / Q000276:immunology* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D007378:Interleukins / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology*; D007700:Kinetics; D051379:Mice; D008819:Mice, Nude; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic; D014162:Transfection / Q000379:methods; D016212:Transforming Growth Factor beta / Q000096:biosynthesis; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D007376:Interleukin-2; D007378:Interleukins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor