Enhanced FcαRI‐mediated neutrophil migration towards tumour colonies in the presence of endothelial cells

Abstract

Neutrophils potently kill tumour cells in the presence of anti-tumour antibodies in vitro.However, for in vivo targeting, the neutrophils need to extravasate from the circulation by passing through endothelial barriers. To study neutrophil migration in the presence of endothelial cells in vitro, we established a three-dimensional collagen culture in which SK-BR-3 tumour colonies were grown in the presence or absence of an endothelial barrier. We demonstrated that -in contrast to targeting FcγR on neutrophils with mAbstargeting the immunoglobulin A Fc receptor (FcαRI) instead triggered neutrophil migration and degranulation leading to tumour destruction, which coincided with release of the pro-inflammatory cytokines interleukin (IL)-1β and tumour necrosis factor (TNF)-α. Interestingly, neutrophil migration was enhanced in the presence of endothelial cells, which coincided with production of significant levels of the neutrophil chemokine IL-8. This supports the idea that stimulation of neutrophil FcαRI, but not FcγR, initiates crosstalk between neutrophils and endothelial cells, leading to enhanced neutrophil migration towards tumour colonies and subsequent tumour killing.Keywords: Bispecific antibody r Chemotaxis immunotherapy r HUVEC r IgA IntroductionNeutrophils represent the most populous type of cytotoxic effector cells within the blood and their numbers can easily be increased by treatment with granulocyte colony-stimulating factor (G-CSF) [1]. Because depletion of these cells resulted in increased tumour outgrowth in animal models, neutrophils may play a role in tumour Immunol. 2012Immunol. . 42: 1815Immunol. -1821 Importantly, anti-tumour monoclonal antibodies (mAbs) or bispecific Abs (BsAbs) -which link Fc receptors on immune cells and tumour-associated antigens (TAAs) on tumour cells -enhance neutrophil-mediated tumour cell lysis [8][9][10]. Initially, the immunoglobulin (Ig) G receptor FcγRI was proposed as a potent target for initiation of neutrophil-induced Ab-mediated tumour cell lysis. In recent years, however, it was demonstrated that targeting the IgA Fc receptor (FcαRI) resulted in more effective neutrophil-mediated Ab-dependent tumour cell lysis [11][12][13][14][15][16][17][18][19]. Furthermore, killing was initiated through non-apoptotic pathways, which coincided with autophagic characteristics [20]. Moreover, triggering of FcαRI induced recruitment of neutrophils into tumour colonies [9]. We recently demonstrated that IgA induced significant release of the neutrophil chemoattractant leukotriene B 4 (LTB 4 ) [21]. Thus, neutrophils represent interesting effector cells for Ab immunotherapy of cancer. However, in order to achieve Ab-mediated lysis of solid tumours in vivo, neutrophils need to extravasate from the circulation into the tumour. Therefore, we now investigated Ab-induced neutrophil migration towards tumour colonies in the presence of an endothelial cell barrier. Results and discussion Targeting FcαRI induces migration, degranulation and release of pro-inflammatory cytokinesNeutroph...

Blocking Fcα Receptor I on Granulocytes Prevents Tissue Damage Induced by IgA Autoantibodies

“…This induces a positive migration loop that can be very efficient for killing invading bacteria at mucosal sites where IgA is the predominant Ab (14). Moreover, we also showed that targeting FcaRI very effectively induced leukotriene B4-dependent neutrophil recruitment into tumor colonies, which led to destruction (38). Thus, we postulated that FcaRI may promote tissue damage in diseases mediated by IgA autoantibodies.…”

The era of the immunoglobulin A Fc receptor FcαRI; its function and potential as target in disease

“…Moreover, targeting FcαRI, but not FcγR, resulted in neutrophil migration. Destruction of either mamma carcinoma or colon carcinoma colonies in three‐dimensional culture systems was observed due to LTB4 release and concomitant neutrophil accumulation after cross‐linking of FcαRI . It was furthermore demonstrated that targeting FcαRI on neutrophils induces autophagic tumor cell death and to a lesser extent tumor necrosis .…”

A comparison of anti-HER2 IgA and IgG1 in vivo efficacy is facilitated by high N-glycan sialylation of the IgA

“…6,7 Moreover, IgAmediated FcaRI activation appears to actively recruit PMN toward tumor cells. 8,9 Since tumor-killing by IgA depends on activation of the FcaRI and that of IgG1 is assumed to be mainly mediated by FcgRIIIa, it might be superior to the corresponding IgG1 when treating patients carrying the FcgRIIIa F158 allele in whom IgG1 efficacy is reduced compared to carriers of the V158 allele. 10,11,12 Very recently, it has been demonstrated not only that macrophages can mediate tumor cell killing by IgA2, but more importantly that this occurs in vivo.…”