Critical Investigation of the Usability of Hepatoma Cell Lines HepG2 and Huh7 as Models for the Metabolic Representation of Resectable Hepatocellular Carcinoma

SIMPLE SUMMARY: Energy metabolism plays a central role in the liver. Therefore, metabolic alterations in liver cancer are fundamental for the development of diagnostic screening and therapeutic intervention. The aim of our experimental study was to investigate the extent to which commonly used hepatoma cell lines (HCLs) sufficiently represent tumor cells from hepatocellular carcinoma (HCC) from a metabolic point of view. To that end, we successfully established a method for the isolation of primary human hepatoma cells (PHCs). We present the unsurprising finding that cell lines are a poor substitute for primary cells. Surprisingly, our transcript data revealed that malign metabolic adaptions had already occurred in non-tumor-bearing liver tissue of HCC patients. In PHCs, we observed that downregulated metabolic key players showed a correlation with malign transformation and were predominantly pronounced in multilocular HCC. These findings should be taken into account for the future optimization of HCC models for in vitro research. ABSTRACT: Metabolic alterations in hepatocellular carcinoma (HCC) are fundamental for the development of diagnostic screening and therapeutic intervention since energy metabolism plays a central role in differentiated hepatocytes. In HCC research, hepatoma cell lines (HCLs) like HepG2 and Huh7 cells are still the gold standard. In this study, we characterized the metabolic profiles of primary human hepatoma cells (PHCs), HCLs and primary human hepatocytes (PHHs) to determine their differentiation states. PHCs and PHHs (HCC-PHHs) were isolated from surgical specimens of HCC patients and their energy metabolism was compared to PHHs from non-HCC patients and the HepG2 and Huh7 cells at different levels (transcript, protein, function). Our analyses showed successful isolation of PHCs with a purity of 50–73% (CK18+). The transcript data revealed that changes in mRNA expression levels had already occurred in HCC-PHHs. While many genes were overexpressed in PHCs and HCC-PHHs, the changes were mostly not translated to the protein level. Downregulated metabolic key players of PHCs revealed a correlation with malign transformation and were predominantly pronounced in multilocular HCC. Therefore, HCLs failed to reflect these expression patterns of PHCs at the transcript and protein levels. The metabolic characteristics of PHCs are closer to those of HCC-PHHs than to HCLs. This should be taken into account for future optimized tumor metabolism research.