Biochemical and functional characterization of aminopeptidase N expressed by human melanoma cells.
A cell surface protein expressed on melanoma cells, but not on normal melanocytes, was biochemically and functionally characterized. Microsequencing of the M(r) 143,000 affinity-purified protein revealed amino acid sequence identity to aminopeptidase N (EC 3.4.11.2). In situ expression, indirect immunofluorescence, and Western blotting demonstrated that aminopeptidase N is tightly associated with extracellular matrix components. A specific polyclonal antiserum and the competitive inhibitors of aminopeptidase N, bestatin and amastatin, inhibited invasion of an aminopeptidase N-expressing metastatic melanoma cell line through the reconstituted basement membrane Matrigel in a dose-dependent manner. In vitro digestion of Matrigel with affinity-purified aminopeptidase N revealed an enzyme-sensitive M(r) 160,000 protein. These experiments suggest a role for aminopeptidase N in melanoma invasion of basement membranes.
Menrad
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Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104.
Speicher
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D
Wacker
J
J
Herlyn
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M
D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D000911:Antibodies, Monoclonal / Q000276:immunology; D018826:CD13 Antigens; D005109:Extracellular Matrix / Q000201:enzymology; D006801:Humans; D008545:Melanoma / Q000201:enzymology* / Q000473:pathology; D008970:Molecular Weight; D009361:Neoplasm Invasiveness; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000626:Aminopeptidases; D018826:CD13 Antigens