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Study on N-Glycomics in Malignancies of Digestive System

Author: ZhaoYunPeng
Tutor: GaoChunFang
School: Second Military Medical University
Course: Clinical Laboratory Science
Keywords: N- sugar group Tumor markers Based on DNA sequencing instrument fluorescent sugar electrophoresis Fucose glycosylated Primary hepatocellular carcinoma Colorectal cancer Gastric cancer
CLC: R735
Type: PhD thesis
Year: 2011
Downloads: 80
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Abstract

Malignancies is currently one of the major diseases that endanger human health, early detection, early diagnosis and early treatment is crucial for the prognosis of cancer patients. The diagnosis of the tumor from the qualitative to the quantitative, positioning has made significant progress. Representative tumor marker alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA), a non-invasive screening and secondary diagnosis. Malignant tumor formation is a process involving multiple factors and multiple genes, the biological behavior of the multi-stage, difficult to obtain common single specific antigen, tumor blood diagnostic studies is a continuous development and understanding of the process. In recent years, the rapid development of Glycomics (Glycomics) study provides a new opportunity for the study of tumor biology and tumor markers. Glycosylation is important to protein post-translational modified forms, 70% of the protein in the body are all glycoproteins. (Sugar glycosyltransferase, glycosidase) inactivation or some embryonic cell malignant transformation due to glycosylation enzymes active enzyme maturity tends to still activated, causing changes in the structure of cell surface carbohydrates . Therefore, the study of these tumor-associated carbohydrate chains characteristic changes have important significance for the early diagnosis of the tumor, process monitoring, prognostic evaluation and therapeutic targets looking. For us based on the fluorescence DNA sequencer sugar electrophoresis (DSA-FACE) technology provides a simple, rapid, high-throughput detection method of N-glycans, more looking for a new sugar tumor markers revealed an entirely new avenues of research . Through large-scale study of clinical samples in this study, three common digestive malignancies (liver cancer, colorectal cancer, and gastric cancer) occurred characteristic changes of the N-sugar group in the development process mapping analysis, establish and evaluation based on N - sugar group map differences of multi-parameter analysis of the diagnostic mode (diagnostic model), aims to improve the sensitivity and specificity of digestive cancer diagnosis. The first part: N-glycomics diagnostic significance in primary hepatocellular carcinoma and its mechanism of this study in the analysis of liver fibrosis, hepatocellular carcinoma (HCC) and normal control groups characteristic N-sugar the group map based on the application of logistics regression establish two math diagnostic model for identification of liver fibrosis and HCC, using ROC curves to assess the diagnostic efficacy of the indicators. Followed by another independent collected 477 cases of HCC, 62 patients with liver cirrhosis, 80 cases of HBV carriers and 79 healthy controls were serum used to verify the effectiveness of the new diagnostic model. Transferase enzyme expression levels in view of the change in level of serum N-glycans glycosylation and intracellular glycosylation is closely related to the application of RT-PCR and Western-blotting method for detection of fucosylated metabolic factors GDP-fuc-Tr expression in HCC tissues and corresponding adjacent tissues. GDP-fuc-Tr by transfection overexpression silence recombinant explore its proliferative activity of the liver cells. The results show that: the New the diagnostic model CscoreA and CscoreB validation group sensitivity in HCC are up to 80% or more, to some extent, to fill the blank of AFP negative patients, the lack of effective diagnostic; GDP-fuc-Tr in next to cancer and cancer tissues, mRNA the level of expression was no significant difference; cancer tissue and cancer paraneoplastic GDP-fuc-Tr proteins of different sizes in normal tissues, suggesting that there may be structural differences, but the expression was no statistical difference; GDP-fuc-Tr over expression and interference recombinant liver no significant effect on the proliferative activity of the cells and liver cancer cells. Part II: the establishment and evaluation of colorectal cancer diagnostic model based analysis of serum N-glycomics analysis of colorectal adenomas, colorectal cancer and healthy controls on the basis of the characteristics of each group N-glycome map, logistics regression method to establish math diagnostic model: CRCglycoA used for differential diagnosis of colorectal cancer and healthy controls the; CRCglycoB used for differential diagnosis of colorectal cancer and colorectal adenomas; New diagnostic formula back in the retrospective validation group, prospective validation group and postoperative return visit group on behalf of assess its diagnostic effectiveness. Map the structure of the N-glycomics analysis found, the core fucose colorectal structure the sum of abundance (sumfuc) below colorectal adenomas with healthy controls, this study using lectin blotting (Lectin-blotting) captured in serum and tissues core fucose protein to be confirmed. And application of the RT-PCR method for detection of fucose glycosylation-related metabolic factors GDP-fuc-Tr and expression in cancer tissue and corresponding paraneoplastic Fut8 in organizations. The results show that: the area under ROC curve CRCglycoA with CEA in the modeling group were 0.92 and 0.81. Relative critical value of 2.5ng/ml of CEA CRCglycoA sensitivity of 23%, the accuracy rate increased 12%; area under the ROC curve of CRCglycoB CEA in the modeling group was 0.81 and 0.73, respectively. Relatively CEA critical value of 2.5ng/ml CRCglycoB accuracy increased by 15%, sensitivity is increased by 28% compared with CEA; the retrospective validation groups, and prospective validation group, CRCglycoA sensitivity 22-25% improve the accuracy of 12-17.5%. CRCglycoB accuracy similar to CEA, the sensitivity increased by 30%. CRCglycoA, CRCglycoB values ??were significantly decreased in the postoperative follow-up group. Lectin-blotting results confirmed that the serum of colorectal cancer, the LCA combination of core fucose protein below colorectal adenomas and the healthy control group. Organization, colorectal core fucose protein content is lower than its paired adjacent tissue, but no significant difference. At the mRNA level, Fut8 expression in tumor tissue was significantly lower than the adjacent tissues, while no significant difference in GDP-fuc-Tr expression in tumor and paraneoplastic organization. Part III: N-glycomics research in this study in the diagnosis of gastric cancer using DSA-FACE, detected 184 cases of subjects (80 patients with gastric cancer, 25 cases of gastric ulcer and 89 healthy controls), serum N-sugar Photos spectrum, analysis and comparison of gastric cancer, gastric ulcer and healthy control groups between the characteristic changes. Application logistics regression method based on mathematical diagnostic model for the differential diagnosis of gastric cancer and healthy controls, named GCglyco, using ROC curves to evaluate the diagnostic effectiveness. Gastric cancer is divided into four according to the TNM classification, analysis comparing N-glycans each peak in gastric cancer progression, commonly used in clinical gastric cancer markers (CEA, CAl9-9, CAl25, CA72-4, etc.) correlation. The results show that: the the gastric peak5 and peak9 significantly increased in the peak2, 3,4,6 and peak7 significantly reduced; structure analysis revealed that gastric total core fucosylated level significantly lower than the control group and the disease control group, similar the results colorectal found. GCglyco logp5 / 4 of the area under ROC curve was 0.937 and 0.897, respectively. , GCglyco correct rate increased by 24% compared with the commonly used marker of gastric cancer. logp5 / 4 gradually increased with the severity of the tumor. The correlation analysis found a negative correlation Peak3, 6 and sumfuc, with TNM, peak9 positive correlation with TNM into CEA with sugar chain has relevance, and CA19-9 and negative peak8 into related. Starting this whole concept of this study is to learn from the tumor glycomics seek common characteristics between the N-sugar change in each tumor; N-glycomics analysis techniques used in the early diagnosis of a variety of digestive malignancies, thereby establishing their math diagnostic model, to some extent, improve the effectiveness of the diagnosis of the tumor, and the correlation analysis of the sugar chain commonly used clinical markers to lay the foundation for the subsequent establishment of an effective multi-parameter diagnostic model; exception of a variety of tumors core rock fucose-modification phenomenon for further research to reveal the mechanism of tumor development, and provide a theoretical basis for looking for direct diagnostic markers and potential therapeutic targets.

Study on N-Glycomics in Malignancies of Digestive System

Abstract

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