Proteomics Research On Serum From Patients Of Gastric Cancer? Hepatic Cancer And Ovarian Cancer

Objective:We used two intensive modern proteomics approaches to identify potential diagnostic markers in serum of gastric cancer patients, hepatic cancer patients and ovarian cancer compared to the serum from healthy control people. Methods: Method:1) Mass spectrometry (Time of flight mass spectrometry) based proteomics following extensive protein fractionation by magnetic beads was used to compare the serum of patients with gastric cancer and hepatic cancer to the serum from healthy control people. Method:2) Mass spectrometry (Ultra high resolution OrbiTrap mass spectrometry) based quantitative proteomics following extensive protein fractionation by 2D-nano-LC was used to compare serum of women with ovarian cancer and women with benign ovarian tumors to healthy women. Quantitation was achieved by isobaric tags for relative and absolute quantitation (iTRAQ). Results:Result from method 1:Mass peaks of mass/charge (m/z) 2863Da and 4965Da could differentiate the gastric cancer patients from the healthy control people. Mass peaks of m/z 1618Da and 4965Da could differentiate the hepatic cancer patients from the healthy control people. Mass peak of m/z 4965Da was overexpressed in the serum of both gastric cancer patients and hepatic cancer patients. Result from method 2:we obtained quantitative data on 326 proteins. Proteins with expression ratios of over 1.2-fold in increase or at least 1.5-fold in decrease were considered differentially expressed. We identified 9 proteins that were overexpressed and 75 proteins that were underexpressed in ovarian cancer compared to the healthy control people. On the benign ovarian tumor, we identified 32 proteins that were overexpressed, and 103 proteins that were under-expressed compared to the healthy control people. Differentially expressed proteins were obtained with 77 proteins overexpressed and 43 proteins underexpressed in the ovarian cancer compared to the benign ovarian tumor. Among the differential expressed proteins, we interpreted 8 important proteins, including protein PARD3, SRP1-alpha, LAMA4, LRP16, IgSF2, NRAMP1, NF-E2-related factor 1 and APOA4. Using Western Blotting technology, we validated 3 important differential proteins, namely, protein APOA4, PARD3 and NRAMP1. In the three, the western blotting result of APOA4 verified the quantitative proteomic results. APOA4 protein showed a good stability for individual in each group. APOA4 protein showed 0.7 in the ovarian cancer serum and 1.2 in the benign tumor serum in the proteomic profiling, compared to value of 1 in the healthy control people. Protein PARD3 was not clearly separated in the western blotting experiment. Protein NRAMP1 showed 1.3 in the ovarian cancer serum and 0.7 in the benign tumor serum in the proteomic profiling, compared to value of 1 in the healthy control people. Conclusion:Using functional magnetic bead based sample fractionation method combined with MALD I-TOF MS can screen potential specific biomarkers in serum of gastric cancer, hepatic cancer and it is a promising method to find and establish potential specific biomarkers for gastric cancer and hepatic cancer. The iTRAQ-labeled proteome profiling applied to symptomatic ovarian cancer cases identifies a large number of differential serum proteins on the serum of women with elevated CA-125, which helped identify proteins to differentiate the malignant ovarian tumor from the benign ovarian tumor.8 important differential proteins were interpreted on the biological aspect. Protein NRAMP1 had roughly consistent tendency in western blotting verification with the proteomic profiling, but was not stable in individuals; therefore, Protein NRAMP1 was not good enough for a potential biomarker. A novel protein, APOA4, was found potential to be a marker to differentiate the malignant to the benign tumor in the serum having elevated CA-125.