BILE-ACID SYNTHESIS BY THE HUH-7 CELL-LINE DERIVED FROM A HUMAN HEPATOCELLULAR-CARCINOMA

Bile acids in conditioned media used for culture of the HuH-7 cell line, derived from a human hepatocellular carcinoma, were analyzed by gas chromatography and gas chromatography/mass spectrometry to ascertain the presence or absence of any abnormalities in bile acid metabolism. Cholic and chenodeoxycholic acids, the primary bile acids of humans, were found in the conditioned media, and more than half of the bile acids were conjugated with glycine but not with taurine or sulfuric acid. In addition, 3beta-hydroxy-5-cholenoic, 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestanoic and 3alpha,7alpha-dihydroxy-5beta-cholestanoic acids were found in the media, and most of the 3beta- hydroxy-5-cholenoic acid was in a sulfated form, while all of the cholestanoic acids were unconjugated. Since the cells had been cultured in serum-free media, all these bile acids had to have been newly synthesized and conjugated. In this study, 3beta-hydroxy-5-cholenoic acid, a presumed intermediate for the alternative pathway of chenodeoxycholic acid synthesis, was the major bile acid synthesized by the HuH-7 cells. These results suggest that HuH-7 cells may employ some unusual and unique metabolic pathways for the production of bile acid.