Background: Aminopeptidase N (APN) has been reported to play important roles in tumor cell invasion and tumor angiogenesis. Its expression is associated with poor prognosis in patients with colon, pancreatic and lung cancers.
Objectives: The aim of this study is to evaluate antitumor effect of a humanized anti-APN antibody in mouse tumor models.
Methods: Subcutaneous tumor and/or tail vein metastasis models were established in immune deficient mice using cell lines abundantly expressing APN (B16 melanoma cells stably transfected with APN (APN-B16), PC-14 and H1299) and scarcely expressing APN (A549). These tumor-bearing mice were intraperitoneally administered a humanized antibody against APN. Sizes of subcutaneous tumor were measured and numbers of tumor nodules on the lung surface were counted. Tumor sections were immunostained with CD31 antibody to assess microvessel density.
Results: The administration of anti-APN antibody significantly reduced the tumor growth in the mice bearing APN-B16, PC-14 and H1299 but not A549. Microvessel density in the tumors was also reduced.
Conclusion: This humanized anti-APN antibody can suppress growth of tumor abundantly expressing APN probably through inhibiting angiogenesis.