| Proteome research is hotspot in life science field. Serum as sample, is attracting scientist's interests in proteomics because serum potentially carries an archive of important histological information serving to improve early disease detection. The analysis of serum, however, is analytical challenging due to the high dynamic concentration range, furthermore, low concentration protein were always combined with high concentration protein. In this thesis, human serum was separated with hybrid multidimensional liquid chromatography, the protein in those fractions was identified by Matrix Assistant Laser Desorption Ionization - Time Of Flight Mass Spectrometry(MALDI-TOF MS). With the comparison the results between health and cancer human serum, some biomarkers of cancers, such as gastric cancer, lung cancer and esophageal cancer, were obtained. The thesis includes five parts as follows:1. Review on human serum proteomics. The research methods and technologies in proteomics were introduced. The recent progress of human serum proteomics research was reviewed.2. Experiment The equipments used, the agents used and the experimental methods were described in detail.3. The separation of human serum by SEC-RPLC and detection withMALDI-TOF MS. In this part, the human serum sample was denatured by 5 mol·L-1 urea solution, which can dispel the interactions between albumin and other proteins/peptides in serum. Then the sample was grouped by size exclusionchromatography (SEC), and thus eliminating high molecular weight proteins, such as albumin and so on., and then separated further with reversed phase liquid chromatography (RPLC). The fractions of serum were detected by MALDI-TOF MS. The results indicated that more than 300 proteins/peptides (<15kD) were detected without digested with trypsin. Comparing MALDI-TOF MS detection results between the denatured and normal serum, more than 80 kinds of low molecular weight proteins/peptides combined with albumin could be obtained.4. The separation of human serum by IEC-RPLC and detection withMALDI-TOF MS. The human serum was separated by weak cation exchange chromatography (WCX) and weak anion exchange chromatography (WAX), respectively. The results indicated that the better separations should be achieved with WAX. The fractions of human serum obtained from WAX were separated further with RPLC and detected with MALDI-TOF MS. The results indicate that the high concentration proteins such as albumin and globulin , can be isolated and influenced the detection of low concentration proteins. If the fractions were digested with trypsin before separated with RPLC, the peptide mixture should be separated by RPLC and detected with MALDI-TOF MS. The result shows that more than 700 peptides can be detected with MALDI-TOF MS. According to the differences of these peptides between healthy and cancer patients' serum digested with trypsin, the biomarkers of tumors for diagnosis can be obtained.5. Screening biomarkers for tumor diagnosis. The presented methods in this paper were applied for the investigation of gastric cancer, lung cancer and esophageal cancer serum proteomics. With the comparisons the MALDI-TOF MS data between healthy and cancer patients' serums, the biomarkers of tumor diagnosis of the three kinds cancers can be achieved. (1) Four kinds of biomarkers for gastric cancer diagnosis with M/Z was 3247, 3905,3953, 4247 can be obtained based on 21 gastric cancer samples and the sensitivity and specificity should reach to 100% if any two biomarkers be used for gastric cancer diagnosis. (2) Three biomarkers for lung cancer diagnosis with M/Z 2211, 4385and 5006 were obtained from 6 patients. The sensitivity and specificity should reach to 83.3% (5/6) and 100% (10/10), respectively. (3) Three biomarkers for esophageal cancer diagnosis with M/Z 2825, 3247 and 4141 can be obtained from 10 patients. The sensitivity and specificity should reach to 90% (9/10) and 100%(10/10), respectively.
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