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Abstract

Aminopeptidase N (APN/CD13), a Zn2+-dependent ectopeptidase, is localized on the cell surface and functions as a transmembrane protein. Increased expression and activity of APN have been postulated to correlate with the aggressive behavior of several tumor types. In this study, the osteosarcoma cell line MNNG/HOS was stably transfected with an expression vector capable of expressing the antisense transcript of APN. Four stably transfected clones, the control clones and parental cells were characterized. Stable integration of the antisense vector was confirmed by PCR analysis of genomic DNA. Competitive RT-PCR revealed that mRNA expression of antisense-transfectants was decreased to approximately 37% of the control cell line. The activity assay showed that the enzymatic activity of APN was inhibited to approximately 51% of the control cell line. Antisense-transfection had no influence on the cellular proliferation measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, on the motility in Transwell chambers, and on the adhesive potential to collagen I. However, an in vitro invasion assay revealed a significant decrease in the number of cells that migrated through a reconstituted membrane (51% of the control cell line). The adhesive potential to Matrigel was also affected (73% of the control cell line). Furthermore, under in vivo conditions, a reduced potency to metastasize to the lung was shown in an experimental metastasis assay in nude mice. These findings demonstrate that APN plays an active role in the cellular attachment and proteolytic degradation of the extracellular matrix in the metastatic process of osteosarcomas.

Aminopeptidase N (CD13): Expression, Prognostic Impact, and Use as Therapeutic Target for Tissue Factor Induced Tumor Vascular Infarction in Soft Tissue Sarcoma

“…Aoki et al reported CD13 expression on tumor cells with variability according to the STS subtype in a small series [26] , but there is no investigation published differentiating between vascular and perivascular presence of CD13 versus presence of CD13 on sarcoma cells in human tissues. CD13 has been described to contribute to osteosarcoma migration and invasion [27] , [28] , but overall, only little is known on the functional role of CD13 in sarcoma cells.…”

Targeting aggressive osteosarcoma with a peptidase-enhanced cytotoxic melphalan flufenamide

“…In former studies, it has been shown that ANPEP/CD13 enzymatic activity aids invasion of HGOS cells, a process contributing to the aggressiveness of the disease. 11 , 14 – 16 , 46 These observations can be attributed to the pivotal role of ANPEP/CD13 in remodeling the extracellular matrix and promoting angiogenesis, two processes implicated in HGOS metastasis. Moreover, in our study, biopsy samples of poor responders showed higher levels of ANPEP mRNA expression in comparison with that of good responders.…”

“… 11 – 13 In osteosarcoma, ANPEP has been identified as a driver of cell migration and invasion. 14 – 16 The aminopeptidase activity of ANPEP has been associated with the activation of PI3K and MAPK pathways, 14 , 15 known contributors to HGOS pathogenesis and metastasis. 17 , 18 High-ANPEP expression was linked to poor survival in osteosarcoma patients.…”

Effect of Preeclampsia Serum on Human Uterine Spiral Artery Smooth Muscle Cell Apoptosis in a Coculture Model with Cytotrophoblasts

“…CTB invasive ability was assayed by using transwell inserts according to the method reported by Kido et al [23,24]. SMCs were placed in the transwell lower chamber, and CTBs in the transwell upper chamber.…”