Differentially expressed genes in TGF-β1 sensitive and resistant human hepatoma cells

The pathway of growth inhibitory cellular signal transduction by transforming growth factor β1 is largely unknown. Although several cellular proteins have been shown to be involved in the pathway, others remain to be identified. To search for other involved proteins, differentially expressed genes were examined in two human hepatoma cell lines that were respectively sensitive and resistant to growth inhibition by TGF-β1. Two such genes (SB31 and SB16) were characterized and found to be 100% homologous to leucine-rich β2-glycoprotein and the ribosomal protein S25, respectively. SB31 was coordinately expressed with the TGF-βI type II receptor, implicating a possible interaction. Expression of both genes in different cell lines can be broadly correlated with the sensitivity of the cell lines to growth inhibition by TGF-β1. SB16 expression is strongly suppressed in rat liver regeneration after partial hepatectomy. suggesting that it may have a role in liver growth.