A novel human hepatoma cell line, FLC-4, exhibits highly enhanced liver differentiation functions through the three-dimensional cell shape.

We characterized three-dimensional human hepatoma cell lines, functional liver cell (FLC) cell lines, to establish a highly differentiated hepatoma cell line. We investigated the effect of extracellular matrix and cell morphology on liver-specific gene expression in FLC cells. The hepatocyte nuclear factor-4α (HNF-4α) and other liver-specific gene expressions were enhanced in spherical FLC-4 cells on EHS-gel, but other human hepatoma cells such as HepG2 did not show the enhancement. Importantly, the liver-specific gene expression levels in spherical FLC-4 cells cultured on EHS-gel were comparable to those of human liver and were much higher than those of other human hepatoma cell lines. The major matrix components and growth factors in EHS-gel did not affect cell shape and liver functions. To exclude any effect of the extracellular matrix, we made spherical FLC-4 cells by actin filament disruption. The actin-disrupted spherical cells also showed an enhanced liver-specific gene expression. We concluded that three-dimensional cell shape per se is one of the most important determinants of liver differentiation functions in FLC-4 cells. Cell morphology-dependent induction of liver-specific gene expression was mediated through microtubule organization. In conclusion, differentiation of FLC-4 human hepatoma cell line can be enhanced to a human liver-like level through the three-dimensional cell shape in a microtubule-dependent manner.