Proteomic analysis on metastasis-associated proteins of hepatocellular carcinoma tissues

Objective A comparative proteomic approach was used to identify and analyze proteins relevant to metastasis of hepatocellular carcinoma (HCC). Methods Proteins extracted from 12 liver tumor tissue specimens (6 with metastases and 6 without) were separated by two-dimensional gel electrophoresis (2-DE). Comparative analyses of 2-DE protein patterns between the two groups were done using computerized image analysis. Selected proteins exhibiting statistically significant alternations were identified by mass spectrometry. Immunohistochemistry, Western blotting and RT-PCR were performed to examine the expressions of the candidate proteins. Results 16 proteins including HSP27, S100A11, CK18 were identified using mass spectrometry, which were related to cell mobility, signal transduction, and energy metabolism respectively. Of these, HSP27 was found to be uniquely over-expressed in 2-DE maps of all metastatic HCCs when compared to the non-metastatic HCC tissues. Immunohistochemistry and Western blotting of HCC tissues confirmed this difference while RT-PCR did not. Conclusion There are different proteins working together that affect the metastasis of HCCs. The overexpression of HSP27 may serve as a biomarker for early detection and therapeutic targets to the metastatic phenotype of HCC. The role of HSP27 in HCC metastasis warrants further investigation.