Application of proteomics to the study of hepatocellular carcinoma and some related diseases

Effect of Derris scandens extract on a human hepatocellular carcinoma cell line

The incidence rate of hepatocellular carcinoma (HCC) remains high in numerous countries, including Thailand. There are numerous different lines of HCC treatment; however, various side effects and the resistance of cancer cells during treatment remain issues. At present, traditionally used herb plants have been widely used as alternatives to cancer therapy. Derris scandens is a Thai traditional herb which is commonly found in Thailand and widely used as a traditional medicine for numerous different diseases. The cytotoxicity of D. scandens ethanolic extract on a HCC cell line (HCC-S102) was determined using an MTT assay. Following treatment with D. scandens ethanolic extract, the induction of apoptosis was determined by Annexin V and dead cell assays, and then confirmed by the upregulation of cleaved poly(ADP-ribose) polymerase. Furthermore, a proteomic approach was used in order to study protein alteration upon treatment with D. scandens ethanolic extract coupled with liquid chromatography-tandem mass spectrometry analysis for protein identification. The results suggested that D. scandens ethanolic extract resulted in cytotoxicity against HCC-S102 cells, as the half-maximal inhibitory concentration values were 36.0±1.0, 29.6±0.6, and 22.6±1.5 µg/ml at 24, 48 and 72 h, respectively. Apoptotic cells were induced following treatment with D. scandens. The comparative proteomic profiles of D. scandens ethanolic extract-treated and untreated cells revealed various protein targets for anticancer activity including heterogeneous nuclear ribonucleoprotein (hnRNP) K, hnRNP A2/B1, stomatin-like 2 and GAPDH. In the present study, the anticancer activity of D. scandens ethanolic extract was demonstrated to affect the cell proliferation of HCC-S102 via an apoptotic pathway. The alteration in these proteins provides a better understanding of the mechanism of action of D. scandens, which may be a promising anticancer agent for the treatment of patients with HCC in the future.

Identification of ZAG Protein as a Novel Serologic Biomarker Candidate for Liver Cancer

To identify Zinc-alpha-2-glycoprotein (ZAG) expression in HCC for serum biomarker, by analyzing the serum proteome of the patients suffering from primary hepatocellular carcinoma (HCC), liver cirrhosis and healthy donors. The serum proteome of the patients from HCC, liver cirrhosis and healthy donors were separated and identified by two-dimensional electrophoresis. The differentially expressed proteins were analyzed by peptide mass fingerprint based on MALDI-TOF-MS and SWISS-PROT or BLAST nr database searching. RT-PCR and Western blotting analysis were used to confirm expression of ZAG in HCC. Five differentially expressed proteins were identified. Albumin, Serotransferrin, CD5 antigen-like precursor ( IgM - associated peptide) were down-regulated in HCC, ZAG and Ig gamma-1 chain C region were up-regulated in HCC. ZAG, a lipid mobilizing factor, is a member of the major histocompatibility complex (MHC) class I family of protein. Five proteins which were found differentially expressed in HCC provided useful information for screening diagnostic tumor markers of human HCC. ZAG might be a novel candidate serum biomarker for HCC early diagnosis.

Current advances in tumor proteomics and candidate biomarkers for hepatic cancer

Tumor proteomics apply proteomics techniques to tumor biological research, mainly by screening candidate biomarkers for early tumor diagnosis, prognosis and treatment. Hepatocellular carcinoma (HCC) is a type of malignant tumor with one of the highest death rates in the world. With the advent of the post-genomic age, tumor biological research developing the technology of proteomics has become a major focus of researchers. The discovery of novel candidate biomarkers is one of crucial problems for the early diagnosis of HCC. In general, there are three distinct types of candidate biomarkers for HCC based on different areas: biochemical biomarkers, antigenic biomarkers and epigenetic biomarkers. This review mainly discusses current advances in the problems and prospects of candidate biomarker for the early diagnosis of HCC, discovered by technologies of tumor proteomics.