Chemokines, or chemotactic cytokines, and their receptors have been discovered as essential and selective mediators in leukocyte migration to inflammatory sites and to secondary lymphoid organs. Besides their functions in the immune system, they also play a critical role in tumor initiation, promotion and progression. There are four subgroups of chemokines. The CXC or alpha subgroup is one of the four and can be further subdivided in the ELR(+) and ELR(-) chemokines. Members that contain the ELR motif bind to CXC chemokine receptor 2 (CXCR2) and are angiogenic. In contrast, most of the CXC chemokines without ELR motif bind to CXCR3 and are angiostatic. An exception is the angiogenic ELR(-)CXC chemokine stromal cell-derived factor-1 (CXCL12/SDF-1), which binds to CXCR4 and CXCR7 and is implicated in tumor metastasis.

The CXC receptors and their ligands are promising targets for drug development. The first approved and marketed drug is plerixafor (AMD3100), a small molecule inhibitor of the CXCR-4/SDF-1 axis, used for stem cell mobilization. CXCR1 and CXC chemokine receptor 2 (CXCR2) are believed to be crucially involved in the direct migration and activation of leukocytes. Their ligands are supposed to play a key role in several inflammatory diseases and this makes them and their receptors attractive therapeutic targets for inflammatory diseases such as COPD, asthma, psoriasis, ulcerative colitis and rheumatoid arthritis.

Related report:
Competitor Analysis: CXCR and CXCL Agonists and Antagonists
 

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