Increased APN/CD13 and acid aminopeptidase activities in head and neck squamous cell carcinoma.

Abstract

Involvement of peptidases in carcinogenic processes of several tumor types has been investigated in recent years. Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers worldwide and accounts for more than 90% of all head and neck cancers. Increased understanding of its pathophysiology has led to implication of several proteinases, specially matrix metalloproteinases, in its genesis, growth, and dissemination. However, very little is known about involvement of peptidases in this neoplasm. Seventeen HNSCC tissue samples were selected for the study. Tumor and normal tissue samples were frozen for enzymatic study. The catalytic activity for a pool of peptidases (PSA, APN/CD13, APB, APA, Asp-AP, CAP, DPPIV/CD26, NEP/CD10, and PGI) was measured fluorometrically. The activity of 2 cell surface aminopeptidases (APN/CD13 and APA) and a cytosolic aminopeptidase (Asp-AP) was significantly increased in HNSCC tissues. These data show the involvement of cell surface and cytosolic peptidases in the mechanisms underlying HNSCC.