Proteomic-based analysis for identification of potential serum biomarkers in gallbladder cancer.

Gallbladder cancer is the most common malignant tumor of the biliary tract. Early diagnosis of gallbladder cancer is difficult because of the latent onset and lack of good biomarkers. To identify new biomarkers that improve the early diagnosis and/or serve as possible therapeutic targets in gallbladder cancer is essential. In the present study, serum proteins were separated by two-dimensional gel electrophoresis (2-DE) in 3 patients with gallbladder cancer and 3 healthy volunteers. The differentially expressed spots were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Western blotting and immunohistochemistry were performed to verify the expression of certain candidate proteins. Protein expression and clinical correlation was evaluated. We found that 64 protein spots were significantly changed in gallbladder cancer. Twenty-four proteins including S100A10, haptoglobin, cystatin-B, profilin-1 and superoxide dismutase were successfully identified. Among these proteins, S100A10 and haptoglobin were validated using Western blotting. Immunohistochemically, the expression of S100A10 and haptoglobin proteins was found to be higher in gallbladder cancer tissues compared to that in gallbladder adenoma, liver cholangiocarcinoma and cholecystitis tissue. Patients with high expression of S100A10 and haptoglobin were linked to late stage disease and poor clinical prognosis. Our data suggest that combined comparative proteomic analysis by 2-DE and MALDI-TOF-MS is an effective method for identifying differentially expressed proteins in serum samples. These proteomic approaches could be used for identifying new serum biomarkers in gallbladder cancer. S100A10, haptoglobin and other identified proteins may be potential molecular targets for early gallbladder cancer diagnostics and therapeutic applications.

[Proteomic study of gallbladder cancer, with special reference on the expression and significance of annexin A3].

OBJECTIVE: To explore the potential molecular targets for diagnosis and treatment of gallbladder cancer by analyzing and comparing the proteomes expressed in human gallbladder cancer and benign gallbladder tissues. METHODS: The proteins expressed were analyzed using two-dimensional gel electrophoresis. The differentially expressed proteins in tumors were also analyzed by mass spectrometry (MS). AnnexinA3 expression was examined by streptavidin peroxidase immunohistochemical technique on paraffin-embedded tissue sections from 50 patients of gallbladder cancer and 38 cases of chronic eholecystitis. RESULTS: Protein extracts of individual sample in each type of tissues were separated on two-dimensional gels. There were forty six differentially expressed proteins in the tissue samples of gallbladder cancer. Seventeen proteins were successfully identified by MS, in which nine proteins were overexpressed in tumors and the other eight proteins were underexpressed. The positive expression rates of annexinA3 in gallbladder cancer was significantly higher than that in chronic cholecystitis, and the difference was statistically significant (74.0% vs 21.1%, P < 0.01). In the gallbladder cancer, no correlation was obtained between annexinA3 and age, gender or histologicl type (P > 0.05), but overexpression of annexinA3 correlated significantly with those cases with a lower histological grading (40.0% vs 82.5%, P < 0.05); lymph node or distant metastasis (40.9% vs 100%, P < 0.05); or a shorter survival time after operation (50.0% vs 93.8%, P < 0.05). CONCLUSIONS: Significant discrepancies in protein expression exist among gallbladder cancer and benign gallbladder tissues. AnnexinA3 plays an important role in the initiation and progression of human gallbladder cancer.

[Comparative proteomic analysis of human gallbladder carcinoma].

OBJECTIVE: To find out potential molecular targets for gallbladder carcinoma diagnosis and treatment by analyzing and comparing the proteins expressed in human gallbladder carcinoma tissue and benign gallbladder tissue. METHODS: Proteomic analysis of 6 human gallbladder carcinoma tissues and 6 benign gallbladder tissues was carried out. Total proteins of the carcinoma tissue and benign gallbladder tissue were separated by two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed and identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Immunohistochemistry was used to examine the expression of PEBP1 protein in an independent series of samples. RESULTS: Protein extracts of individual samples in each type of tissues were separated on two-dimensional gels. There were forty six differentially expressed proteins in the gallbladder carcinom tissues. Seventeen proteins were successfully identified by MS, in which nine proteins were overexpressed in tumors while the other eight proteins were underexpressed. The increased level of PEBP1 protein in gallbladder carcinoma was further confirmed by immunohistochemical analysis. CONCLUSION: Seventeen differentially expressed proteins were successfully characterized by comparative proteomic analysis. Those results may provide scientific foundation for screening the molecular biomarkers which can be used in diagnosis and treatment of gallbladder carcinoma, as well as to improve its prognosis and provide a new clue for carcinogenesis research of gallbladder carcinoma.