MSX-122

MSX-122 is a n orally bioavailable inhibitor of CXCR4 with potential antineoplastic and antiviral activities. CXCR4 inhibitor MSX-122 binds to the chemokine receptor CXCR4, preventing the binding of stromal derived factor-1 (SDF-1) to the CXCR4 receptor and receptor activation, which may result in decreased tumor cell proliferation and migration. CXCR4, a chemokine receptor belonging to the GPCR (G protein-coupled receptor) gene family, plays an important role in chemotaxis and angiogenesis and is upregulated in several tumor cell types; it is also a co-receptor for HIV entry into T cells. The chemical structure of MSX-122 is very similar to that of WZ811. (In Vitro) :MSX-122 is a partial antagonist of CXCR4, inhibiting CXCR4/CXCL12 actions, with an IC50 of ~10 nM. MSX-122 shows no inhibition on cAMP reduction mediated by their corresponding ligands CCR3/CCL5 and CCR5/CCL5. MSX-122 (100 nM) potently blocks invasion of 78% MDA-MB-231 cells. However, MSX-122 does not suppress T-tropic HIV infection and is inactive in calcium flux assay. (In Vivo) :MSX-122 (10 mg/kg, i.p.) blocks inflammation induced by carrageenan and lung fibrosis induced by bleomycin in mice. MSX-122 (4 mg/kg, i.p., daily) blocks metastasis in an experimental animal model of breast cancer metastasis. Furthermore, MSX-122 (10 mg/kg i.p., daily) significantly decreases the numbers of hepatic micrometastases.