Proteome analysis of hepatocellular carcinoma cell lines with different metastasis potentials by two-dimensional liquid chromatography

AIM: To analyze the proteome of hepatocellular carcinoma cell lines, MHCC97-H (high metastasis) and MHCC97-L (low metastasis), with different metastasis potentials by two-dimentional liquid phase chromatographic fractionation followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS).

METHODS: Cell lysates of MHCC97-H and MHCC97-L were fractionated according to PI using chromatofocusing with analytical columns in the first dimension, followed by separation of the proteins in each PI fraction using nonporous reversed-phase high performance liquid chromatography (HPLC). A two-dimensional map of the protein content for each cell line based upon pI versus hydrophobicity as detected by UV absorption was generated and a differential display map indicating the presence of up- or down-regulated proteins was exhibited using ProteoVue and DltaVue software. The different proteins were digested by trypsin and MALDI-TOF/MS was performed.

RESULTS: Image analysis of two-dimensional map revealed 72 differentially expressed proteins between MHCC97-H and MHCC97-L cells, and 9 protein peaks (including M2 pyruvate kinase, α-subunit of ATP synthase, heat shock protein 60, Toll-like receptor 9, flavoprotein oxygenase, pro-calreticulin, manganese superoxide dismutase, nm23-H1, and G-protein-coupled receptor kinase 5) were further identified by tryptic digestion, peptide mass fingerprinting and mass spectrometry. Four proteins were up-regulated while 5 were down-regulated in MHCC97-H cells.

CONCLUSION: The identified differentially expressed proteins may play important roles in the metastasis of hepatocellular carcinoma.