The study of ANGPTL4 gene in the molecular mechanism of hypoxia in colorectal cancer
| Autor: | Shu-chun Yang, 楊淑君 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 Colorectal cancer (CRC) has been continuously ranked third in the list of top ten cancer death rate chart in Taiwan for both men and women. The amount of new patients increases constantly every year. This research implemented oligonucleotide microarray chip technology to conduct a comprehensive and high efficient gene expression analysis to determine how hypoxia may affect the molecular mechanisms of colorectal cancer, in which the ANGPLT4 gene was selected for this process. Because the role of this type of gene in colorectal cancer remains unknown, it was the target gene in this research. Oligonucleotide microarray chip technology was applied to select genes of colorectal cancer cells to demonstrate their differences under hypoxic conditions. After comparing the SW480 and SW620 cells of colorectal cancer under 48 hours of hypoxic and normoxic environments, there were 2,046 and 1,535 genes, respectively, upward adjusted different genes. Bioinformatics tools such as Gene Ontology (GO), DAVID, and KEGG were also used for analysis. The result of analysis on biological process of the SW480 cell, cellular process demonstrates the highest percentage at 60.5% while cell and cell part takes 76.6% as the highest scale of cellular components and binding takes 70.6% as the highest scale of molecular function. In addition, the result of analysis on biological process of the SW620 cell, cellular process demonstrates the highest percentage at 57.6% while cytoplasm takes 43.4% as the highest scale of cellular components and binding takes 68.1% as the highest scale of molecular function. The ANGPTL4 gene had the highest expression among all the other genes during upward movement. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis to measure the expression of the ANGPTL4 gene by colorectal cancer SW480 and SW620 cell lines in hypoxic and normoxic environments separately for 24 and 48 hours, the ANGPTL4 gene in both cell lines had increased expression in hypoxia and had decreased in normoxic environment. The experiment demonstrated that the ANGPTL4 gene played different roles in various conditions. Tumor cells had increased expression in hypoxic condition but reduced expression in a normal oxygen environment. In addition, the expression of the ANGPTL4 protein from clinical tissue specimens of colorectal cancer patients was performed. Immunohistochemical staining of the tissue samples from 48 clinical colorectal cancer patients provided results for the ANGPTL4 protein analysis that were consistent with the cancer cell line experiment. Forty-one tissues of the ANGPTL4 (85.4%, 41/48) protein, which were visible in the cytoplasm of tumor cells, were detected and had a positive reaction in 48 patients. The TNM stage I~III assessment of the ANGPTL4 protein expression had a positive reaction. In the TNM stage II and III assessments, the ANGPTL4 protein expression for these stages were 77.3% and 100%, respectively. Statistical analysis showed a significant correlation with the TNM staging (p |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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