Tumor cell lysis by activated human neutrophils: Analysis of neutrophil-delivered oxidative attack and role of leukocyte function-associated antigen 1

Abstract

The lysis of tumor cells, and other nucleated mammalian cells, by neutrophilic polymorphonuclear leukocytes (PMNs) triggered by phorbol myristate acetate (PMA) represents a widely used model system to dissect the PMN cytolytic armamentarium, potentially responsible for the cell damage at tissue sites of PMN activation. Although oxidants are generally considered to be instrumental in the target lysis by PMNs, the mediators actually involved remain a matter of controversy. Moreover, other factors potentially crucial to the lysis have not been clearly identified. In order to reexamine the determinants of the cytolytic process, we studied the events underlying the PMA-triggered PMN-delivered attack against two different targets, selected on the basis of preliminary experiments (B lymphoblastoid Daudi cells and erythroleukemic K 562 cells). The results suggest that the lysis is promoted by hypochlorous acid (HOCl) or a compound with characteristics very similar to HOCl itself. No evidence was obtained for the intervention or contribution of hydrogen peroxide (H2O2), hydroxyl (OH.) radicals, and the major HOCl-derived chloramines. PMNs appeared to use 35% of the generated H2O2 to produce HOCl, while the remainder appears to be consumed by PMNs themselves and target cells as well. Moreover, PMNs and target cells coaggregated at an early step of the cytolytic reaction, through a process efficiently prevented by a monoclonal antibody (MoAb J-90) directed against leukocyte function-associated antigen-1 (LFA-1). The inhibition of the PMN-target aggregation by the MoAb J-90 resulted in the impairment of the lysis, despite a normal generation of HOCl. Thus, the data demonstrate that the PMA-triggered lysis of tumor target cells by PMNs requires at least two events, occurring simultaneously: the LFA-1-mediated effector-target adherence and the PMN production of HOCl. The intervention of the LFA-1-mediated PMN-target adherence in the PMA-triggered lysis is likely to allow PMNs to focus HOCl on the target cell surface and suggests that the process requires a sort of molecule to molecule recognition at the effector-target surface level.

The intriguing role of polymorphonuclear neutrophils in antitumor reactions

“…94,95 Furthermore, patients showing disease response to treatment have a significantly greater production of PMN oxidants, such as HOCl, which is regarded as instrumental in tumor cell lysis. 55,77 Evidence suggests that production of the tumoricidal long-lived oxidant HOCl, along with up-regulation of PMN surface integrins, may also contribute to the antineoplastic efficacy of infusional therapy with TNF-␣. [96][97][98] However, besides their involvement in the therapeutic efficacy of certain cytokines, PMNs may be partly responsible for the toxic side effects of high-dose systemic cytokine therapy.…”

“…54 Recent dissection of the cytolytic armamentarium of PMNs has suggested a primary role for hypochlorous acid (HOCl) in mediating tumor cell lysis by activated PMNs after their leukocyte function-associated antigen 1-dependent recognition of the target cell surface. 55 Furthermore, a distinct adhesion pathway, mediated by CD11b/CD18 up-regulation on activated PMNs, enables these cells to adhere to the vascular endothelium and create a subjacent microenvironment, allowing accumulation of oxidants and proteolytic enzymes at local concentrations sufficient to cause endothelial damage and matrix degradation. 56 In addition, PMN-released HOCl reacts with primary amines to form relatively stable chloramines with immunostimulatory properties.…”

Apoptotic human cells inhibit migration of granulocytes via release of lactoferrin

“…Since lactoferrin has potent ability to inhibit neutrophil migration, it seems likely that in tumors in which neutrophils play a supportive role, limitation of neutrophil infiltration through lactoferrin administration could be therapeutically beneficial. However, in tumors in which neutrophils are absent, we propose that, given the known antitumor effects of neutrophils (68)(69)(70)(71), encouragement of neutrophil infiltration through inhibition of lactoferrin may effect tumor destruction. Our results might predict that tumors in which apoptosis is prominent would produce lactoferrin in situ.…”

Hydrodynamic Shear Regulates the Kinetics and Receptor Specificity of Polymorphonuclear Leukocyte-Colon Carcinoma Cell Adhesive Interactions

“…The mAbs BU15 (anti-CD11c), 84H10 (anti-CD54), and 4B4 (anti-CD29) were obtained from Beckman Coulter (Fullerton, CA). The blocking F(abЈ) 2 anti-CD102 mAb CBR-IC2/2 and anti-CD54 MHCD54F were from Caltag Laboratories (Burlingame, CA). Anti-CD50 mAb 76205.11 was purchased from R&D Systems (Minneapolis, MN).…”

“…1). Their tumoricidal ability requires close contact with the tumor cells (2,3) and is associated with the production of reactive oxygen species, proteases, membrane-perforating agents, and soluble mediators of cell killing such as TNF-␣, IL-1␤, and IFNs (1). However, several independent studies have demonstrated that PMNs enhance the metastatic potential of tumor cells.…”