Back to Search
Start Over
Tumor cell alpha-N-acetylgalactosaminidase activity and its involvement in GcMAF-related macrophage activation.
- Source :
-
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology [Comp Biochem Physiol A Mol Integr Physiol] 2002 May; Vol. 132 (1), pp. 1-8. - Publication Year :
- 2002
-
Abstract
- Alpha-N-acetyl galactosaminidase (alpha-NaGalase) has been reported to accumulate in serum of cancer patients and be responsible for deglycosylation of Gc protein, which is a precursor of GcMAF-mediated macrophage activation cascade, finally leading to immunosuppression in advanced cancer patients. We studied the biochemical characterization of alpha-NaGalase from several human tumor cell lines. We also examined its effect on the potency of GcMAF to activate mouse peritoneal macrophage to produce superoxide in GcMAF-mediated macrophage activation cascade. The specific activity of alpha-NaGalases from human colon tumor cell line HCT116, human hepatoma cell line HepG2, and normal human liver cells (Chang liver cell line) were evaluated using two types of substrates; GalNAc-alpha-PNP (exo-type substrate) and Gal-beta-GalNAc-alpha-PNP (endo-type substrate). Tumor-derived alpha-NaGalase having higher activity than normal alpha-NaGalase, had higher substrate specificity to the exo-type substrate than to the endo-type substrate, and still maintained its activity at pH 7. GcMAF enhance superoxide production in mouse macrophage, and pre-treatment of GcMAF with tumor cell lysate reduce the activity. We conclude that tumor-derived alpha-NaGalase is different in biochemical characterization compared to normal alpha-NaGalase from normal Chang liver cells. In addition, tumor cell-derived alpha-NaGalase decreases the potency of GcMAF on macrophage activation.
- Subjects :
- Animals
Cell Division
Humans
Hydrogen-Ion Concentration
Lipopolysaccharides pharmacology
Mice
Signal Transduction drug effects
Substrate Specificity
Tumor Cells, Cultured
alpha-N-Acetylgalactosaminidase
Hexosaminidases metabolism
Macrophage Activation drug effects
Macrophage-Activating Factors pharmacology
Vitamin D-Binding Protein pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1095-6433
- Volume :
- 132
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
- Publication Type :
- Academic Journal
- Accession number :
- 12062184
- Full Text :
- https://doi.org/10.1016/s1095-6433(01)00522-0