| In order to know the function of the polypeptide: N-acetylgalactosaminyltransferase-Ts(ppGalNAC-Ts) in the course of tumour's generating and developing , we examined theenzyme's expression at mRNA level with RT-PCR method. Methods: The first part is toexamine the expression of ppGalNACT-1, 2, 9 in different rumour cells. The secondpart is to find out the variation of ppGalNAcT2's expression in tumour cells exposed toY -rays and the effect of several remedies added to the culture medium. Results: 1) InSHG44 neuroglia cancer cells, the expression of ppGalNAcT-2 is extremely low, while inSGC-7901 gastric carcinoma cells and K562 Leukaemia cells, it's very high, the lesserbeing the ovary cancer cells(CD+); but in multiple medulla carcinoma cells ,theexpression of ppGalNAcT-2 is rare. The order is: K562 Leukaemia cells > SGC-7901gastric carcinoma cells > ovary cancer cells(CD+) > multiple medulla carcinoma cells >NIH3T3 fibroblast cells and SHG44 neuroglia cancer cells, this result probably corresponds with the viewpoint that ppGalNAc-T2 is the key-enzyme in biosynthesis of O-glycan and O-glycan mostly consists in mucin. Aside this, the expression of ppGalNAc Tl appears low, and ppGalNAc T9 is barely expressed in ovary cancer cells and in Leukaemia cells . 2) After irradiated by -rays, the expression of ppGalNAcT-2 in tumour cells was somewhat reduced, and it was negatively reletive to the dosage; Theexpression of ppGalNAcT-2 was somewhat enhanced in the irradiated tumour cells afterseveral remedies were added to the culture medium, this phenomenon hinted us these remedies had the biologic protection at cell levels. Conclusion: These results hereinbefore evinced that the standards of expression of ppGalNAcTl and T9 were lower, but that of ppGalNAcT-2 was higher and differed in different tumour cells; the expression of ppGalNAcT-2 was all high in cells that originated from endoblast, such as gastric carcinoma cells; but it was low in cells which originated from ectoderm, such as neuroglia cancer cells. After irradiation, the expression of ppGalNAcT2 was decreased in K562 cells, from which we concluded that irradiation could repress the expression of ppGalNAcT2, but some remedies could make the expression of ppGalNAcT2 somewhat promoted again., and this situation was reverse to that of MMPs. Through the experiment, we primarily confirmed that ppGalNAcT2 is relative to some biological specificity of cancer cells, such as tumour's invasiveness and migration. This initial work is the foundation in seeking particular depressor or activator of ppGalNAcTs and MMPs, and it will provide the experimental evidence to cancer diagnosis and clinical therapy. |
