title: Constitutive production of IL-2 by human carcinoma cells, expression of IL-2 receptor, and tumor cell growth.
abstract: Human carcinomas spontaneously express abundant IL-2R beta but little IL-2R alpha on the cell surface, contain mRNA for IL-2R beta- and IL-2R alpha-chains, and may be inhibited in growth by exogenous IL-2. To study the relationship between IL-2R expression and growth inhibition by IL-2, carcinoma cells were transduced with IL-2R alpha and IL-2R gamma cDNAs or IL-2R beta antisense cDNA. Transfectants with the IL-2R alpha gene expressed high levels of the alpha- and beta-receptor chains and showed increased binding of [125I]IL-2. Exogenous IL-2 at the picometer concentrations inhibited their growth, and Abs to IL-2R alpha- or IL-2R beta-chains reversed the inhibition. After transduction of IL-2R beta antisense cDNA, gastric carcinoma (HR) cells no longer expressed IL-2R beta-chain, and their proliferation was depressed in the absence of exogenous IL-2. Transduction of IL-2R gamma-chain cDNA into tumor cells increased sensitivity to growth inhibition by exogenous IL-2 of a squamous cell carcinoma line, but not of HR or renal cell carcinoma lines. All of the parental and transduced tumor cell lines were found to constitutively express intracellular IL-2, detectable by immunostaining or flow cytometry of permeabilized cells. IL-2 was present on the surface of some tumor cells. Intracellular IL-2R beta and IL-2R gamma proteins were also detectable in tumor cells. Using reverse-transcription PCR combined with Southern blots or in situ hybridization, mRNA for IL-2 was found to be present in parental and transduced tumor cells. Expression on human carcinomas of IL-2R beta, inhibition of their growth by IL-2R beta antisense cDNA, and their ability to constitutively produce IL-2 and its presence on the cell surface, all suggest that endogenous IL-2 may play a role in tumor cell growth.
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, PA, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Yasumura
authors.forename: Y
authors.initials: Y
authors.lastname: Suminami
authors.forename: M W
authors.initials: MW
authors.lastname: Sung
authors.forename: S
authors.initials: S
authors.lastname: Nagashima
authors.forename: J
authors.initials: J
authors.lastname: Stanson
authors.forename: T L
authors.initials: TL
authors.lastname: Whiteside
mesh_terms: D001483:Base Sequence; D002277:Carcinoma / Q000276:immunology* / Q000473:pathology*; D002455:Cell Division; D018076:DNA, Complementary / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D018014:Gene Transfer Techniques; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis*; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D007376:Interleukin-2; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2