title: Characterization of variant gamma-glutamyl transpeptidase produced by pancreatocholangiocarcinoma cell lines in a protein-free, chemically defined medium.
abstract: Four pancreatocholangiocarcinoma cell lines (HPC-Y1, HPC-YT, MIA PaCa-2, and HChol-Y1) were established to propagate in a protein-free, chemically defined medium. High gamma-glutamyl transpeptidase (GGTP) activities were showed in their spent media (designated as the secreted (GGTP). Their GGTP activities in the spent media were 125, 85, 110, and 153 IU/L/mg of lyophilized spent media, whereas GGTP activities extracted from their cancer cell lines with bromelain were 105, 37, 86, and 112 IU/L/1 x 10(6) cells, respectively. The chemical characteristics of the GGTPs in the spent media from these cell lines resembled one of the GGTPs, sialic acid-rich GGTP, extracted from normal human pancreas with bromelain treatment as follows: the GGTPs secreted from the cancer cell lines bound to an anion exchange column moved fast on electrophoresis and then showed decreased electrophoretic mobility with neuraminidase treatment, showed a high affinity for concanavalin A and lentil lectin columns, and had an acidic isoelectric point. However, the elution patterns of erythroagglutinating phytohemagglutinin (E-PHA) column chromatography and thermostability tests demonstrated clear differences between the carcinoma GGTPs both in the spent media and cell lines and the sialic acid-rich GGTP of normal pancreas, namely the carcinoma GGTPs treated with neuraminidase showed affinity to E-PHA columns, and, in addition, the GGTPs in the spent media showed an apparent heat resistance at 56 degrees C. These findings indicate that the carcinoma GGTPs have a different oligosaccharide structure from that in normal pancreatic GGTPs.
authors.affiliation: Department of Microbiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Koyama
authors.forename: O
authors.initials: O
authors.lastname: Shiroeda
authors.forename: S M
authors.initials: SM
authors.lastname: Chung
authors.forename: T
authors.initials: T
authors.lastname: Ashihara
authors.forename: J
authors.initials: J
authors.lastname: Imanishi
mesh_terms: D002759:Adenoma, Bile Duct / Q000201:enzymology*; D002460:Cell Line; D002846:Chromatography, Affinity; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D010190:Pancreatic Neoplasms / Q000201:enzymology*; D005723:gamma-Glutamyltransferase / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D003470:Culture Media; D005723:gamma-Glutamyltransferase