Comparative proteomics study on HepG2 human hepatocellular carcinoma cells and 7702 human normal hepatocytes

Objective: To explore the differential proteomics profiles between HepG2 hepatoma cells and 7702 normal hepatocytes, and to screen specific biomarkers for hepatocellular carcinoma. Methods: The cellular total proteins of hepatoma cells and normal hepatocytes were separated using two-dimensional electrophoresis (2-DE). The differentially expressed proteins between the two types of cells were detected and analyzed by imaging analysis, and then the proteins were identified by mass spectrometry. The expression of two important proteins in hepatoma tissues was evaluated by immunohistochemical method. Results: In HepG2 hepatoma cells, 17 differentially expressed proteins were identified, of which 10 proteins were up-regulated and 7 ones were down-regulated as compared to 7702 normal hepatocytes. The proteins mainly included metabolic enzyme, anti-apoptotic proteins and the proteins regulating stress and signal transduction between cells. The up-regulated expressions of annexin A1 and cyclophilin A in hepatoma tissues were verified by immunohistochemistry, and the two proteins were mainly located in the cytoplasm. Conclusion: Protein expression patterns differ greatly between HepG2 hepatoma cells and 7702 normal hepatocytes, and annexin A1 and cyclophilin A may be molecular markers for early detection and targets in hepatocellular carcinoma therapy.