Expression and localization of aminopeptidase A, aminopeptidase N, and dipeptidyl peptidase IV in benign and malignant human prostate tissue.
BACKGROUND
Cell-surface peptidases are ectoenzymes which regulate the access of bioactive peptides to their receptors on cell membranes. Abnormalities in their expression and function result in altered peptide activity which contribute to neoplastic transformation and/or progression.


METHODS
Expression of aminopeptidase A (APA), aminopeptidase N (APN, CD13), and dipeptidyl peptidase IV (DPP IV, CD26) was immunohistochemically examined in 20 benign and 33 malignant prostate tissues (19 primaries and 14 metastases).


RESULTS
Benign prostatic stroma exhibited no APA, APN, or DPP IV immunoreactivity. Stromal cells surrounding prostatic carcinoma cells demonstrated increased APA expression in 24/33 (73%) of tumors. Benign prostatic epithelial cells strongly expressed APN and DPP IV but not APA. In contrast, APN was expressed in > 80% of tumor cells in 5/33 (15%) of specimens, heterogeneously expressed (20-80% of cells positive) in 4/33 (12%) of specimens, and minimally expressed or absent in 24/33 (73%) of tumor specimens, with a similar pattern of expression in primary and metastatic tumors. DPP IV was expressed by > 80% of tumor cells in 18/19 (95%) of primary prostate cancer specimens, but in only 7/14 (50%) of metastases.


CONCLUSIONS
These data show that cell-surface peptidases are differentially expressed by normal prostatic stromal and epithelial cells, with increased expression of APA in the stroma surrounding prostate cancer cells, absent APN expression in most tumor cells, and a decreased frequency of DPP IV expression in metastatic tumors. Further studies will elucidate the biological effects of the presence or loss of cell-surface peptidases in the benign and malignant prostate.
Bogenrieder
T
T
Laboratory of Mammalian Cell Transformation, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Finstad
C L
CL
Freeman
R H
RH
Papandreou
C N
CN
Scher
H I
HI
Albino
A P
AP
Reuter
V E
VE
Nanus
D M
DM
D000368:Aged; D000369:Aged, 80 and over; D000626:Aminopeptidases / Q000032:analysis* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001706:Biopsy; D001859:Bone Neoplasms / Q000201:enzymology / Q000473:pathology / Q000556:secondary; D018826:CD13 Antigens / Q000032:analysis* / Q000276:immunology; D018819:Dipeptidyl Peptidase 4 / Q000032:analysis* / Q000276:immunology; D004848:Epithelium / Q000201:enzymology / Q000473:pathology; D043384:Glutamyl Aminopeptidase; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000201:enzymology / Q000473:pathology / Q000556:secondary; D008175:Lung Neoplasms / Q000201:enzymology / Q000473:pathology / Q000556:secondary; D008198:Lymph Nodes / Q000201:enzymology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000166:cytology / Q000201:enzymology*; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000201:enzymology / Q000473:pathology / Q000556:secondary
D000911:Antibodies, Monoclonal; D000626:Aminopeptidases; D018826:CD13 Antigens; D043384:Glutamyl Aminopeptidase; D018819:Dipeptidyl Peptidase 4