title: Transfection of the mouse ICAM-1 gene into murine neuroblastoma enhances susceptibility to lysis, reduces in vivo tumorigenicity and decreases ICAM-2-dependent killing.
abstract: We determined the expression of intercellular adhesion molecules (ICAM) on neuro-2a cells in order to evaluate whether they were involved in cytolysis of murine neuroblastoma. Fluorescence-activated cell sorting analysis revealed that the control neomycin-resistance-gene-transduced line (neuro-2a/LN) had poor expression of ICAM-1 (mean channel fluorescence, MCF = 3.7). An ICAM-1-positive transfectant of neuro-2a (neuro-2a/ICAM-1+) (MCF = 64.3) was generated to evaluate directly the role of this adhesion molecule in cytolysis. Neuro-2a/ICAM-1+ was more sensitive to LAK killing (69.7% at an effector-to-target ratio of 100:1) compared to neuro-2a/LN (48.6%) (P < 0.001). Blocking of neuro-2a/LN and neuro-2a/ICAM-1+ lysis with anti-ICAM-1 monoclonal antibodies (mAbs) did not account for all the LFA-1-dependent killing. These data indicate that even in neuro-2a/ICAM-1+ cells, other LFA-1 ligands participated in the effector-target interaction. Therefore, we examined these cell lines for ICAM-2 expression. Both neuro-2a/LN and neuro-2a/ICAM-1+ lines expressed ICAM-2 (MCF = 16.4 and 16.5). ICAM-2 accounted for the majority of the LFA-1-dependent killing in the ICAM-1-negative target, neuro-2a/LN, while ICAM-1 played a primary role in the cytolysis of the ICAM-1+ transfectant. Inhibition of lysis in the presence of anti-ICAM-1 and ICAM-2 mAbs was comparable to that seen with the addition of anti-LFA-1 mAb, indicating that other LFA-1 ligands were not involved in this system. ICAM-1 expression was associated with decreased in vivo tumorigenicity, mice inoculated with neuro-2a/ICAM-1+ cells had a significantly longer survival compared to those receiving neuro-2a/LN cells (median survival time 35.5 versus 24.5 days) (P < 0.001). It is important to note that ICAM-1 transfection of murine neuroblastoma did not alter its metastatic potential. We conclude that transfection of mouse neuroblastoma with ICAM-1 increases its sensitivity to in vitro lysis and reduces its in vivo tumorigenicity. In ICAM-1-negative murine neuroblastoma cells, ICAM-2 plays a primary role in cell-mediated lysis.
authors.affiliation: Department of Pediatrics, University of Minnesota, Minneapolis 55455.
authors.forename: E
authors.initials: E
authors.lastname: Katsanis
authors.forename: M A
authors.initials: MA
authors.lastname: Bausero
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.forename: P J
authors.initials: PJ
authors.lastname: Orchard
authors.forename: Z
authors.initials: Z
authors.lastname: Xu
authors.forename: R S
authors.initials: RS
authors.lastname: McIvor
authors.forename: A A
authors.initials: AA
authors.lastname: Brian
authors.forename: B R
authors.initials: BR
authors.lastname: Blazar
mesh_terms: D000818:Animals; D015703:Antigens, CD; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D018799:Intercellular Adhesion Molecule-1; D007376:Interleukin-2 / Q000494:pharmacology; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology*; D051379:Mice; D008805:Mice, Inbred A; D009362:Neoplasm Metastasis; D009447:Neuroblastoma / Q000276:immunology* / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D015815:Cell Adhesion Molecules; C065289:ICAM2 protein, human; D007376:Interleukin-2; D018799:Intercellular Adhesion Molecule-1