DIFFERENT EXPRESSION OF ESTERASE VARIANTS IN RAT HEPATIC AND HEPATOMA-DERIVED CELL-LINES DETECTED BY ELECTROPHORESIS

Esterases in nine rat hepatic and hepatoma-derived cell lines and norm al rat liver homogenate were detected by polyacrylamide gel electropho resis coupled with active staining with alpha-naphthyl acetate or buty rate as a substrate. The esterase band patterns of the non-cancerous a nd oncogene-transformed cell lines were alike, but different from thos e of hepatoma cell lines and normal rat liver homogenate. The former g roups of cells might have completely lost the characteristics of rat l iver parenchymal cells, or else they might have their origin at cells other than liver parenchyma. The esterase patterns of the hepatoma cel l lines (e.g., McA-RH7777) and the normal rat liver highly resembled w ith each other, exemplifying the slight biochemical deviation of cance r from normal cells. However, two-dimensional electrophoretogram for t he McA-RH7777 cell line showed a prominent esterase spot (pI 6.0-M(r) 110 kDa) that was lacking in the normal liver. This result indicates t hat there is invariably some change in esterase expression between the cancer cells and the normal liver cells.