The selective CXCR2 antagonist SB272844 blocks interleukin-8 and growth-related oncogene-α-mediated inhibition of spontaneous neutrophil apoptosis

The aims of this study were to investigate the effects of Interleukin-8 (IL-8) and Growth related oncogene-alpha (Gro-alpha) on neutrophil apoptosis and determine the potential for a selective CXCR2 antagonist to inhibit these responses. IL-8 and Gro-alpha both produced dose dependent inhibition of spontaneous human neutrophil apoptosis after 16 hours incubation (59 +/- 3.5% and 27.5 +/- 3% respectively; EC50s 2.2 +/- 1.8 nM, and 0.5 +/- 0.2 nM respectively). The pro-survival effect of a fixed concentration of agonist (IL-8 or Gro-a) on cultured neutrophils, was abrogated by a selective CXCR2 antagonist SB272844 (KDs 253 nM and 49.9 nM in the presence of IL-8 or Gro-alpha respectively). Our data suggests that the anti-apoptotic effect of Gro-alpha is mediated through CXCR2 as selective CXCR2 blockade with SB272844 can potently abrogate this response. The inhibitory effect of IL-8 may in addition partly be mediated through CXCR1 as SB272844 was less potent in its ability to abrogate the antiapoptotic effects of IL-8 when this agent was used as an agonist. CXCR2 antagonists may have a therapeutic role in controlling neutrophil-driven inflammation by reducing neutrophil recruitment and restoring neutrophils to the tissue clearance pathway of apoptosis. (C) 2002 Elsevier Science Ltd. All rights reserved.