Effect of salivary gland adenocarcinoma cell-derived alpha-N-acetylgalactosaminidase on the bioactivity of macrophage activating factor.
The aim of this study was to clarify the effects of alpha-N-acetylgalactosaminidase (alpha-NaGalase) produced by human salivary gland adenocarcinoma (SGA) cells on the bioactivity of macrophage-activating factor (GcMAF). High exo-alpha-NaGalase activity was detected in the SGA cell line HSG. HSG alpha-NaGalase had both exo- and endo-enzyme activities, cleaving the Gal-GalNAc and GalNAc residues linked to Thr/Ser but not releasing the [NeuAc2-6]GalNac residue. Furthermore, GcMAF enzymatically prepared from the Gc protein enhanced the superoxide-generation capacity and phagocytic activity of monocytes/macrophages. However, GcMAF treated with purified alpha-NaGalase did not exhibit these effects. Thus, HSG possesses the capacity to produce larger quantities of alpha-NaGalase, which inactivates GcMAF produced from Gc protein, resulting in reduced phagocytic activity and superoxide-generation capacity of monocytes/macrophages. The present data strongly suggest that HSG alpha-NaGalase acts as an immunodeficiency factor in cancer patients.
Matsuura
Takashi
T
Department of Oral and Maxillofacial Surgery, Matsumoto Dental University School of Dentistry, Nagano 399-0781, Japan.
Uematsu
Takashi
T
Yamaoka
Minoru
M
Furusawa
Kiyofumi
K
D000230:Adenocarcinoma / Q000201:enzymology*; D002277:Carcinoma / Q000378:metabolism; D045744:Cell Line, Tumor; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases / Q000378:metabolism; D006596:Hexosaminidases / Q000494:pharmacology*; D006801:Humans; D037102:Lectins / Q000378:metabolism; D016215:Macrophage-Activating Factors / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008954:Models, Biological; D009000:Monocytes / Q000378:metabolism; D010587:Phagocytosis; D012468:Salivary Gland Neoplasms / Q000201:enzymology* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D048809:alpha-N-Acetylgalactosaminidase
D037102:Lectins; D016215:Macrophage-Activating Factors; D013481:Superoxides; D006026:Glycoside Hydrolases; D006596:Hexosaminidases; C482722:NAGA protein, human; D048809:alpha-N-Acetylgalactosaminidase