Aminopeptidase N (CD13) neoangiogenic isoform (CD13)

CD13, also known as Aminopeptidase N, is a zinc-dependent metalloprotease that plays a multifaceted role in cell surface proteolysis and signal transduction (UniProt P15144). The neoangiogenic isoform of CD13 is a specific conformation or expression state found exclusively on the endothelial cells of newly formed blood vessels in tumors and inflammatory sites (PubMed: 11830545). Unlike the CD13 found in normal tissues like the kidney or mature myeloid cells, this isoform possesses a unique binding site for peptides containing the Asn-Gly-Arg (NGR) motif (Cancer Res. 62:867-874). This specificity allows for the development of ligand-directed therapies, such as NGR-hTNF, which selectively deliver therapeutic payloads to the tumor vasculature while sparing healthy organs (NIH: PMC3493762). Functionally, CD13 is essential for endothelial cell morphogenesis and migration, making it both a marker and a driver of pathological angiogenesis (PubMed: 11207330). Targeting this isoform can lead to the disruption of the tumor blood supply, increased vascular permeability, and improved delivery of co-administered chemotherapeutic agents (Br J Cancer 103:837-844). Clinical development of CD13-targeted agents has focused on treating solid tumors and lymphomas, often monitoring efficacy through vascular imaging biomarkers like Ktrans (Blood Adv. 4:3648–3658).

Other names

Aminopeptidase NAPNANPEPAlanyl aminopeptidasegp150Microsomal aminopeptidaseNGR-binding CD13

Ligand-directed vascular targeting and enzymatic inhibition of endothelial morphogenesis.