title: Activation of beta 1 integrin fibronectin receptors on HL60 cells after granulocytic differentiation.
abstract: Phorbol esters upregulate the functional affinity of beta 1 integrin receptors for fibronectin on human neutrophils and other leukocytes. We investigated the ability of phorbol myristate acetate (PMA) to stimulate the human promyelocytic cell line HL-60 to adhere to fibronectin, either in its undifferentiated state (HL60) or after dimethylsulfoxide-induced differentiation along the granulocytic pathway (dHL60). PMA stimulated little adherence of undifferentiated HL60 to fibronectin or to the 120-kD chymotryptic cell-binding domain (CBD) of fibronectin. In contrast, PMA stimulated dHL60 cells to rapidly adhere to both fibronectin- and to CBD-coated plastic. PMA-stimulated dHL60 adherence to fibronectin was largely mediated by both alpha 4 beta 1 and alpha 5 beta 1, whereas PMA-stimulated dHL60 adherence to CBD was largely mediated by alpha 5 beta 1. There was little contribution from beta 2 integrins to PMA-stimulated dHL60 adherence to fibronectin or CBD. The inability of undifferentiated HL60 to adhere to fibronectin and CBD did not result from lack of expression of alpha 4 beta 1 or alpha 5 beta 1 because HL60 and dHL60 express similar amounts of both alpha 4 beta 1 and alpha 5 beta 1 on their surface. In addition, 1 mmol/L Mn2+ induced similar amounts of alpha 5 beta 1-dependent adherence of both HL60 and dHL60, showing that alpha 5 beta 1 on undifferentiated HL60 is capable of binding to its ligand. These data suggest that activation of protein kinase C cannot functionally upregulate these beta 1 integrins on undifferentiated HL60 cells. The development of PMA-stimulated beta 1-dependent adherence after granulocytic differentiation of HL60 cells suggests that the differentiated HL60 cell is a useful model for investigating functional coupling of protein kinase C to beta 1 integrin in myeloid cells.
authors.affiliation: Department of Pediatrics, University of Utah School of Medicine, Salt Lake City 84132.
authors.forename: J F
authors.initials: JF
authors.lastname: Bohnsack
authors.forename: J
authors.initials: J
authors.lastname: Chang
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006098:Granulocytes / Q000473:pathology*; D006801:Humans; D019012:Integrin beta1; D016023:Integrins / Q000502:physiology*; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology*; D051381:Rats; D017469:Receptors, Fibronectin / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D019012:Integrin beta1; D016023:Integrins; D017469:Receptors, Fibronectin; D013755:Tetradecanoylphorbol Acetate; D004121:Dimethyl Sulfoxide