| Summary: | 碩士 === 國立中興大學 === 分子生物學研究所 === 95 === The mechanisms of lung cancer carcinogenesis are quite complicated. One of the mechanisms is closely related to the expression of human glycosyltransferase genes. From the viewpoint of glycobiology, carcinogenesis results from disturbed, hyper- or hypo-glycosylation of cell membrane glycoprotein. Abnormal glycoconjugates interfere with intercellular recognition, and in turn increases metastatic potential through adhesion of tumor cells and vascular endothelial cells.
In order to prove the roles of a-1,3 fucosyltransferase IV and a-1,3 fucosyltransferase VI in lung cancer carcinogenesis, we have successfully transfected either FUT 4 or FUT 6 gene into A549 lung cancer cells.
In addition, we also construct FUT 4 gene into pET-20b plasmid and FUT 6 gene into pET-29a plasmid to produce a large amount of fucosyltransferases. After immunizing the chickens, FUT 4 and FUT 6 polyclonal antibodies were successfully purified from the yolks and confirmed by the western blot. We then transfected A549 lung cancer cells with either FUT4 or FUT6 genes, and conducted experiments with PCR, real-time PCR, western blot, flowcytometry, adhesion test and invasion test . The results show that overexpression of FUT4 or FUT6 gene could elevate mRNA and protein level in A549 lung cancer cells and also promote the expression of A549 lung cancer cells surface antigen Lewisx and sialyl-Lewisx. Moreover, overexpression of FUT4 or FUT6 gene could enhance the A549 lung cancer cells adhesion and invasion . The SCID was used for in vivo experiments, and the results demonstrated that overexpression of FUT4 gene could increase lung tumor formation and metastasis. However, overexpression of FUT6 gene represses lung tumor formation and metastasis. In conclusion, both FUT4 and FUT6 genes, especially FUT4 gene, increase not only the local invasion of A549 lung cancer cells, but also their metastatic potential.
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