Transcriptional regulation of transferrin and albumin genes by retinoic acid in human hepatoma cell line Hep3B

Transferrin and albumin, which are both secreted from the human hepatoma cell line Hep3B, were regulated transcriptionally by retinoic acid (RA) in a dose-dependent manner. The cell growth rate was little affected under the same conditions. The treatment of Hep3B cells with RA (10 microM for 48 h) resulted in an 8-fold increase in transferrin protein synthesis, a 10-fold increase in the steady-state transferrin mRNA level, and a 5-fold increase in its transcriptional rate. The same treatment led to 4-fold decrease in albumin synthesis, as well as a 7-fold decline in the steady-state albumin mRNA level and a 4-fold decrease in the transcriptional rate. Cycloheximide and actinomycin D blocked the action of RA, suggesting that RA may regulate transferrin and albumin gene expression indirectly in human liver cells.