Differential expression of C/EBP beta in human normal liver cells and hepatocellular carcinoma cell lines and its correlation with cell death related to endoplasmic reticulum stress / 西安交通大学学报(医学版)

ABSTRACT

Objective To detect the expression profile of transcription factor C/EBPβ in human immortalized normal hepatic cell lines and hepatocellular carcinoma cell lines so as to determine the correlation between C/EBP3 with cell death mediated by endoplasmic reticulum stress in hepatocellular cells.Methods We cultured the human immortalized normal hepatic cells lines HHL5 and HL7702 and hepatocellular carcinoma cell lines SMMC7721;Bel7402,HepG2 and Hep3B.Hep3B cells were used as the cell model in tunicamycin-induced endoplasmic reticulum stress.Cellular morphology was observed under an inverted optical microscope.MTT assay was used to assess the inhibition of cell growth.To detect cell apoptosis,the cells were dyed with Hoechst 33258 and observed using a fluorescence microscope.RToPCR and Western blotting were used to detect the expression of at mRNA and protein levels,respectively.Results We found that normally the mRNA and protein isoform of C/EBPβ,C/EBPβ-1,were both expressed in all of the four hepatocellular cell lines and the two immortalized normal hepatic cell lines,while C/EBPβ protein isoform C/EBPβ-3 was only expressed in the two immortalized normal hepatic cell lines.Tunicamycin increased the expressions of both mRNA and protein of C/EBPβ in Hep3B cells and the increase of protein isoform C/EBPβ-3 was the most remarkable.In Hep3B cells,cell death was induced by tunicamycin through endoplasmic reticulum stress activity.Apoptosis as well as paraptosis was observed in tunicamycin-induced cell death.Conclusion C/EBPβ-3,one of the protein isoforms of C/EBPβ,is only expressed in normal hepatic cell lines,but not in hepatocellular cell lines.C/EBPβ is involved in cell death mediated by endoplasmic reticulum stress activity in hepatocellular carcinoma cells.