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Different processing of bile canalicular antigen in well and poorly differentiated human hepatoma cell lines
Author(s) -
CHIU JH.,
HU CP.,
LUI WY.,
CHANG HM.,
CHANG C.
Publication year - 1993
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1111/j.1440-1746.1993.tb01684.x
Subject(s) - monoclonal antibody , cell culture , microbiology and biotechnology , antigen , antibody , in vitro , biology , cytoplasm , chemistry , biochemistry , immunology , genetics
Hepatocytes, known as polarized epithelia, are composed of sinusoid, basolateral and bile canalicular domains. Using monoclonal antibody and human hepatoma cell lines, the canalicular domain was shown to be established in well‐differentiated lines via vesicle fusion, but not in poorly differentiated lines. To understand the metabolic processing of the bile canalicular antigen in different human hepatoma cell lines, monoclonal antibody C2D4 was produced by immunizing BALB/C mice with human hepatoms cell line HA22T/VGH and fusing sensitized mouse spleen cells with mouse myeloma cells. Using two‐dimensional polyacrylamide gel electrophoresis, the monoclonal antibody C2D4 was shown to react with the same molecule recognized by monoclonal antibody 9B2, which had been known to react with the antigen on the bile canalicular domain of human hepatocytes and hepatoma cells, both in vivo and in vitro. Analysed with pulse‐chase radioimmunoprecipitation, C2D4 precipitated the 140 kD polypeptide through a 1–4 day well‐differentiated cell line, Hep G2; whereas in addition to the 140 kD polypeptide, an 80 kD protein was recognized by C2D4 in a 2 or 3 day poorly differentiated line, SK‐HEP‐1. Together with peptide mapping and subcellular fractionation analysis, the 80 kD protein was postulated to be internally degraded in the intracellular compartment, but not on the cytoplasmic membrane. It was concluded that the human hepatoma cell lines could be a good in vitro model to study the metabolic processing of bile canalicular domains of human hepatocytes. Also, the loss of the cellular polarity in poorly differentiated human hepatoma cell lines provides a good natural variant to study the differentiation and progression of human hepatoma cells.