EPI-X4

EPI-X4 (Endogenous Peptide Inhibitor of CXCR4) is a naturally occurring 16-amino acid peptide derived from the proteolytic cleavage of serum albumin by cathepsins D and E, particularly under acidic conditions such as those found in inflammatory or tumor microenvironments. It serves as a specific endogenous antagonist of the C-X-C chemokine receptor type 4 (CXCR4), a key regulator of cell trafficking and anchorage in the bone marrow. By binding to CXCR4, EPI-X4 inhibits the binding of its natural ligand, CXCL12 (SDF-1), thereby disrupting signaling pathways like ERK phosphorylation that drive the migration and survival of malignant cells. In the context of acute myeloid leukemia (AML), EPI-X4 has been shown to impair the clonogenic growth, migration, and bone marrow engraftment of leukemic stem cells. Beyond oncology, EPI-X4 and its optimized synthetic derivatives are being investigated for potential therapeutic applications in inflammatory diseases and as inhibitors of HIV-1 entry.

Other names

EPI-X4 endogenous inhibitor of CXCR4EPI-X-4 endogenous inhibitor of CXCR4EPI-X 4 endogenous inhibitor of CXCR4Endogenous CXCR4 Inhibitory Peptide