A comprehensive gene expression analysis of human hepatocellular carcinoma cell lines as components of a bioartificial liver using a radial flow bioreactor

Background/Aims: The cells constituting a bioartificial liver are crucial for an effective liver support system. We compared global gene expression profiles in a radial flow bioreactor or a monolayer culture of three functional liver cell lines previously established from human hepatocellular carcinoma. Methods: The expressions of 60 000 genes of the FLC‐4, FLC‐5, and FLC‐7 cell lines were analyzed by the microarray technique with the Affymetrix GeneChip system. Global gene expression profiles were compared with two‐way cluster analysis. Several liver function‐related genes were compared between the bioreactor and culture conditions. Results: Cluster analysis revealed that gene expression profiles of bioreactor‐grown cells resembled those of the normal liver. Genes related to cellular structure were highly expressed in the bioreactor‐grown cells, while genes involved in proliferation or carcinogenesis were suppressed. In the bioreactor‐grown cells, some genes for liver functions were expressed at a level similar to that in normal liver, although none of the cell lines expressed the complete set of genes encoding ammonium metabolism or cytochrome P450 species. Conclusion: The high‐density three‐dimensional culture in the radial flow bioreactor prompted differentiation of the cells. These data may be useful for improving the cells by genetic or pharmacological reinforcement and for monitoring bioartificial livers.