Role of the Aspartyl-Asparaginyl-β-Hydroxylase Gene in Neuroblastoma Cell Motility

• Published in: Laboratory investigation Vol. 82; no. 7; pp. 881 - 891
• Main Authors: Sepe, Paul S, Lahousse, Stephanie A, Gemelli, Brad, Chang, Howard, Maeda, Takashi, Wands, Jack R, de la Monte, Suzanne M
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.2002; Nature Publishing
• Subjects: Antibodies, Monoclonal; Biological and medical sciences; Cell Movement - genetics; Dissemination; Flow Cytometry; Humans; Medical sciences; Mixed Function Oxygenases - genetics; Neuroblastoma - enzymology; Neuroblastoma - genetics; Peptide Fragments - chemistry; Peptide Fragments - immunology; Tumor cell; Tumor Cells, Cultured; Tumors; Human; Cell proliferation; Nervous system diseases; Peptide-aspartate β-dioxygenase; Motility; Enzyme; Pathogenesis; Gene overexpression; Malignant tumor; Neuroblastoma; Malignant glioma; Gene; Medulloblastoma; Central nervous system disease; Tumor progression; Oxidoreductases; Autonomic neuropathy; Tumor cell; High malignancy
• ISSN: 0023-6837; 1530-0307
• DOI: 10.1097/01.LAB.0000020406.91689.7F

Aspartyl (asparaginyl) β-hydroxylase (AAH) is overexpressed in various malignant neoplasms, and high levels of immunoreactivity mainly occur in infiltrating or metastasized tumors. In addition, AAH is abundantly expressed in normally invasive placental trophoblastic cells. These observations led to the hypothesis that AAH may have a role in motility and aggressive behavior of tumor cells. The present study demonstrates that AAH is overexpressed in primary human malignant neuroectodermal tumors, including medulloblastomas and neuroblastomas, and that AAH expression is at a low level or undetectable in the normal mature brain. In the Sy5y neuroblastoma cell line, endogenous expression of the ∼86-kd AAH protein was demonstrated by Western blot analysis, and immunoreactivity predominantly localized to the cell surface by immunocytochemical staining and FACS analysis. Sy5y cells that were stably transfected with the human AAH cDNA had increased levels of proliferating cell nuclear antigen and Bcl-2, and reduced levels of p21/Waf1 and p16. In addition, increased AAH expression enhanced Sy5y cell motility, whereas antisense oligodeoxynucleotide inhibition of AAH significantly reduced Sy5y cell motility and increased the levels of p21/Waf1 and p16. The findings suggest that AAH overexpression contributes to the malignant phenotype of neuroectodermal tumor cells by increasing motility and enhancing proliferation, survival, and cell cycle progression. Because AAH expression is at a low level or undetectable in normal brain, the AAH gene may be a target for treating primitive neuroectodermal tumors.