bestatin

Bestatin, also known as ubenimex, is a small-molecule protease inhibitor originally isolated from Streptomyces species. It is a dipeptide-like compound that inhibits several aminopeptidases, most notably aminopeptidase N (APN, also known as CD13) and aminopeptidase B (APB), with activity against other related enzymes. By targeting these zinc-dependent exopeptidases, bestatin interferes with the removal of amino-terminal residues from peptides.

In terms of mechanism, bestatin acts as a competitive, reversible inhibitor of aminopeptidases. Inhibition of APN and APB can modulate processing of signaling peptides and can influence immune cell function, tumor cell invasion, and peptide turnover. The compound has been studied as a means to enhance immune responses and to limit cancer progression in experimental systems.

Clinical and research use has largely centered on immunomodulation and oncology. Bestatin has been investigated as an immunostimulant and as an adjuvant to cancer therapies in certain countries, with interest in anti-tumor, anti-metastatic, and anti-angiogenic effects observed in preclinical models. It has also been explored in broader contexts, including antiviral or anti-inflammatory investigations, though its clinical use for these indications varies by region and regulatory status.

Administration and pharmacokinetics data indicate that bestatin is orally active and has been evaluated across various dosing regimens. It is generally excreted renally with limited hepatic metabolism. Regulatory approval is not universal; in many regions it remains primarily a research compound or is used in combination therapies rather than as a standalone widely approved anticancer agent.