Over-expression of beta-1,4-galactosyltransferase V increases the growth of astrocytoma cell line.

Our previous study showed that the gene expression of beta-1,4-galactosyltransferase V (beta-1,4-GalT V), preferentially galactosylating GlcNAc1-->6Man of oligosaccharides, increased in the process of astrocytoma progress, with the highest level in grade IV astrocytoma. To investigate the function of this beta-1,4-GalT in cell proliferation, the sense and antisense cDNA of beta-1,4-GalT V was constructed as pcDNA3-HA-GalT V and pcDNA3-anti-GalT V respectively and transfected into SHG cell, a kind of human astrocytoma cell line. The transfection was confirmed with Northern and Western blot assay. It was found that the growth of SHG/HA-GalT V in serum-containing medium was faster than that of mock-transfectant with the vector pcDNA3, whereas the growth of SHG/GalTV-AS was slower than that of mock-transfectant. GalTV-HA/SHG showed a stronger capability for colony formation than that of GalTV-AS/SHG as evaluated by anchorage-independent growth in soft agar assay. This result was consistent with that of the growth curve. By RCA-1 lectin assay, the galactosylation on the surface of GalTV-HA/SHG and SHG/GalTV-AS was stained stronger (P<0.001) and weaker (P<0.05) respectively compared with the mock transfectant. This indicates that beta-1,4-GalT V was involved in the malignant phenotype of astrocytoma cells, possibly causing the high galactosylation on the cell surface.