[Immunoreactivities and messenger RNA expression of aldolase A and B in human hepatoma cell lines]

Subunit specific radioimmunoassay for aldolase isozymes were developed for the quantification of human aldolase A and B. Aldolase B immunoreactivities were predominantly high in adult normal liver, while aldolase A was distinctly low. Aldolase A was high, while aldolase B was low in neonatal liver compared with the adult liver. Aldolase A immunoreactivities were almost the same as those of aldolase B in fetal liver (28 weeks). Aldolase A was predominantly found in human hepatoma tissues, whereas aldolase B was distinctly low in the same hepatoma tissues. With regard to human hepatoma cell lines, aldolase A was also predominantly found in HepG2 and PLC/PRF/5 cell lines, whereas aldolase B levels were extremely low. Almost the same results were obtained from mRNA expression of aldolase A and B in human hepatoma cell lines by the method of northern hybridization. Effects of various reagents on differentiation of hepatoma cell lines were investigated. Neither Dimethyl Sulfoxide (DMSO) and 12-O-Tetradecanoylphorbol-13-acetate (TPA), which are known to be the inducers of differentiation of human leukemia cell lines such as HL-60, nor Transforming Growth Factor-beta 1 (TGF-beta 1) and Hepatocyte Growth Factor (HGF), which are known to be growth inhibitors, could cause the differentiation of hepatoma cell lines in the alteration of aldolase isozymes. The same data were shown in mRNA expression of aldolase isozymes. These results suggest that aldolase A immunoreactivities and mRNA expression are both predominantly high in hepatoma cell lines, and the reagents such as DMSO, TPA, TGF-beta 1 and HGF which tried to differentiate the hepatoma cell lines used in this study were not effective in the alteration of aldolase isozymes.