An antagonist of both the C-X-C chemokine receptor type 4 (CXCR4) and E-selectin (CD62E), with potential antineoplastic activity. Upon administration, CXCR4/E-selectin antagonist GMI-1359 binds to both CXCR4 and E-selectin expressed on endothelial cells. The binding to CXCR4 prevents the binding of stromal-cell derived factor-1 (SDF-1; CXCL12) to CXCR4 and inhibits CXCR4 activation, which may result in decreased proliferation and migration of CXCR4-expressing tumor cells. The binding to E-selectin expressed on endothelial cells prevents their interaction with E-selectin ligand-expressing cancer cells. This may prevent tumor cell activation, migration and metastasis. CXCR4, a chemokine receptor belonging to the G protein-coupled receptor (GPCR) family, plays an important role in chemotaxis and angiogenesis, and is upregulated in several tumor cell types. E-selectin is a cell adhesion molecule involved in cell rolling, signaling and chemotaxis. Its overexpression has been associated with tumor angiogenesis and metastasis in several cancers.