CD26: a multi-purpose pharmacological target

CD26 is a widely expressed transmembrane glycoprotein with peptidase activity in its extracellular domain and which regulates multiple biological processes. It acts mainly as catabolic enzyme for a number of circulating proteins involved in common pathological conditions such as diabetes and cardiovascular disease and may represent a target to modulate bioavailability of crucial substrates. The aim of the present review is to summarize data regarding CD26-based pharmacological interventions. Four main subtopics were identified:1) CD26 as the target of pharmacological inhibitors to increase bioavailability of glucagon-like petide-1 (GLP-1) and hence to enhance GLP-1 glucose-lowering activity in diabetic patients; 2) role of CD26 in the physiology and pathology of the cardiovascular system; 3) the adverse prognostic value of CD26 expression on cancer cells; 4) CD26 down-regulation on lymphocytes as a mechanism of TGF-beta immunomodulation.