title: A three-dimensional tumor cell defect in activating autologous CTLs is associated with inefficient antigen presentation correlated with heat shock protein-70 down-regulation.
abstract: We described previously a CTL clone able to lyse the autologous carcinoma cell line IGR-Heu after specific recognition of an HLA-A2/mutated alpha-actinin-4 peptide complex. Here, we used IGR-Heu, cultured either as standard two-dimensional monolayers or as three-dimensional spheroids, to further analyze the influence of target architecture on CTL reactivity. Interestingly, we found that changes in the tumor structure from two- to three-dimensional induced a dramatic decrease in its capacity to activate autologous CTL, as measured by IFN-gamma and tumor necrosis factor-alpha secretion. These functional alterations were attributable neither to MHC class I expression nor to tumor antigen (Ag) down-regulation, because IGR-Heu, cultured as two- or three-dimensional, expressed similar levels of HLA-A2 and alpha-actinin-4. More importantly, incubation of three-dimensional cells with synthetic epitope completely restored cytokine release by CTL. This defective Ag presentation correlated with a decrease in heat shock protein (hsp)70 expression by three-dimensional tumors compared with two-dimensional cells. Furthermore, transfection of the tumor cells with hsp70 cDNA completely restored the Ag-presenting potential of spheroids and, therefore, cytokine production by T cells. These data strongly suggest that hsp70 down-regulation in three-dimensional cells may result in tumor resistance to the immune response.
authors.affiliation: Centre National de la Recherche Scientifique, Laboratoire d'immunologie des tumeurs, Faculté des sciences pharmaceutiques et biologiques de Paris, Université René Descartes Paris 5, 75006 Paris, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Dangles-Marie
authors.forename: Sophie
authors.initials: S
authors.lastname: Richon
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Behi
authors.forename: Hamid
authors.initials: H
authors.lastname: Echchakir
authors.forename: Guillaume
authors.initials: G
authors.lastname: Dorothée
authors.forename: Jérôme
authors.initials: J
authors.lastname: Thiery
authors.forename: Pierre
authors.initials: P
authors.lastname: Validire
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vergnon
authors.forename: Jeanne
authors.initials: J
authors.lastname: Menez
authors.forename: Moncef
authors.initials: M
authors.lastname: Ladjimi
authors.forename: Salem
authors.initials: S
authors.lastname: Chouaib
authors.forename: Dominique
authors.initials: D
authors.lastname: Bellet
authors.forename: Fathia
authors.initials: F
authors.lastname: Mami-Chouaib
mesh_terms: D017951:Antigen Presentation / Q000276:immunology*; D001483:Base Sequence; D018287:Carcinoma, Large Cell / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D017931:DNA Primers; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D016246:Lymphocytes, Tumor-Infiltrating; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D018840:HSP70 Heat-Shock Proteins