CREB3L3 and hepatocellular carcinoma: In vitro, mimicking the fasted state by depleting serum from the culture medium (glucose 1 g/ml) of a human hepatoma cell line, HepG2 cells, for 18 hours activated CREBH, indicated by the increased abundance of active CREBH, N-terminal CREBH (CREBH-N) (Fig. 1B).