Suppression of Malignant Potentials of A549 Human Lung Cancer Cell Line by Downregulation of the ß4-Galactosyltransferase 1 Gene Expression.

Our previous study demonstrated that downregulation of transcription factor Specificity protein (Sp) 1 suppresses the malignant potentials of A549 human lung cancer cell line with the reduced ß4-galactosylation of highly branched N-glycans on cell surface glycoproteins. The reduced ß4-galactosylation was brought about by the decreased expression of the ß4-galactosyltransferase 1 (ß4GalT1) gene. Herein, we examined whether the reduced ß4-galactosylation by decreasing the ß4GalT1 gene expression suppresses the malignant potentials of A549 cells. In the ß4GalT1-downregulated cells, the ß4-galactosylation of highly branched N-glycans was reduced in several glycoproteins such as lysosome-associated membrane protein-1 and E-cadherin. The anchorage-independent growth and migratory ability of the ß4GalT1-downregulated cells decreased when compared with the control cells. Furthermore, the phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) decreased in the ß4GalT1-downregulated cells. These results indicate that downregulation of the ß4GalT1 gene decreases the ß4-galactosylation of highly branched N-glycans and the phosphorylation of p44/42 MAPK, and suppresses the malignant potentials of A549 cells.

Identification of a gene encoding glutathione S-transferase that is related to anthocyanin accumulation in buckwheat (Fagopyrum esculentum).

Anthocyanins are a group of flavonoids found in buckwheat (Fagopyrum esculentum) and many other plant species; however; little is known about their mechanisms of synthesis and regulation in buckwheat. We previously reported a spontaneous mutant buckwheat line that shows the green stem phenotype; this line does not accumulate anthocyanins but synthesizes flavonol and proanthocyanidin in the stem. Here, we used this line and lines developed by this line to search for genes related to anthocyanin accumulation in buckwheat. The lines with green stem showed flavonoid-3-O-glucosyltransferase activity against UDP-glucose, indicating that the flavonoid-3-O-glucosyltransferase gene was not controlling the green stem trait. We therefore searched the buckwheat genome database for a gene encoding glutathione S-transferase (GST), a flavonoid-binding protein that transports flavonoids to the vacuole, and identified a candidate gene, FeGST1. Expression analysis showed that FeGST1 was expressed in wild type buckwheat but not in the green stem lines. Linkage analysis with an F2 segregating population produced by crossing between the green stem line and a self-compatible line showed that FeGST1 segregated with stem color without any recombination. This indicates that the green stem trait could be caused by homozygous non-functional alleles of the FeGST1 locus.