Roles And Molecular Mechanisms Of ?2,3-Sialylation In The Development Of Bladder Cancer

Sugar,like nucleic acids,lipids and proteins,is all important components of cells.It is not only the main source of cellular energy,but also plays a crucial role in the regulation of life activities.Research has shown that abnormal modification of glycosylation and tumor development are closely related.Glycosylation modifications are mainly catalyzed by glycosyltransferases.Aberrant expression of glycosyltransferases plays an important role in the regulation of tumorigenesis.It can also serve as a biomarker for tumor interventions to provide specific targets.Sialic acid is a negatively charged nine-carbon monosaccharide,often located in the last part of the sugar chain,capable of binding to cell surface proteins and other proteins,and it is also an important molecule for transmitting biological information.Sialyltransferase is a type of glycosyltransferases.It can attach sialic acid to Gal or Gal NAc via both ?2,3-and ?2,6-linkages or to proteins on ?2,8-linkages.Sialyltransferase is divided into four groups based on the newly formed glycosidic bond types following sialyltransferase: ST3 Gal I-VI,ST6 Gal I-II,ST6 Gal NAc,I-VI,and ST8 Sia I-VI.It has been found that there are sialylation in many tumor antigens.Among them,the major sialylated antigens are SLe A and SLe X,which have been proved to be highly expressed in many malignant tumors to some extent,which is related to poor prognosis.Bladder cancer is the most common malignant tumor in the urinary system and has a high morbidity and mortality all over the world.Its early diagnosis and personalized treatment are the key to successful treatment.So looking for an effective diagnosis and treatment target is still the central issue of current research.At present,there is little research on the role and molecular mechanism of sialylation in the development of bladder cancer.?.Objective1.To detect the difference of ?2,3-sialyltransferase expression in bladder urothelial carcinoma and normal bladder urothelium and its influence on the survival rate of bladder cancer patients;2.To investigate the effect of ?2,3-sialyltransferase on the biological behavior of bladder cancer cells such as growth,proliferation,migration and invasion;3.To clarify the molecular mechanism of ?2,3-sialyltransferase mediated malignant biological behavior of bladder cancer cells.?.Methods1.Genomic microarray analysis of the collected clinical samples was performed by gene chip.The distribution and expression of glycosyltransferase in bladder cancer tissues and normal bladder urothelium were detected by Real-time PCR,immunohistochemistry and Western-blot.Kaplan-Meier statistical analysis of?2,3-sialyl acylase on the survival rate of bladder cancer patients.2.The expression of sialyltransferase in different bladder cancer cell lines was detected by Real time PCR sialic acid family analysis;the expression differences of ST3Gal4 and ST3Gal6 in different bladder cancer cell lines and normal bladder urothelial cells were detected by Western-blot;The cell lines of 5637 and T24 stably overexpressing ST3Gal4 and ST3Gal6 were constructed by liposome transfection,G418 and limiting dilution methods.The expression of ST3Gal4 and ST3Gal6 were detected by Real-time PCR,Western-blot,flow cytometry and immunofluorescence staining In stable cells 5637 / ST3Gal4,5637 / ST3Gal6,T24 / ST3Gal4 and T24 / ST3Gal6.3.The effects of ?2,3-sialyltransferase on the growth,proliferation,migration and invasion of bladder cancer cells were investigated by plate clone,CCK8, transwell migration and invasion,scratch test and flow cytometry cycle test.Tumorigenicity assay examines the effect of ST3Gal4 and ST3Gal6 overexpression on bladder cancer cells in vivo tumorigenicity.4.The molecular mechanism of ?2,3-sialyltransferase on the malignant phenotype of bladder cancer cells was studied by Western blot and the expression and localization of related molecules were detected by immunohistochemistry.?.Results1.A variety of glycosyltransferases in bladder cancer tissue expression levels were different,ST3Gal4 and ST3Gal6 expression was significantly different between the two in bladder cancer tissue expression levels compared with normal bladder urinary tract were down to varying degrees,and Its expression down-regulation in bladder cancer is associated with low prognosis.2.The bladder cancer cell lines stably overexpressing ST3Gal4 and ST3Gal6 have been successfully constructed by Western blot,immunofluorescence,flow cytometry and Real-time PCR.3.Overexpression of ST3Gal4 and ST3Gal6 respectively inhibited the growth,proliferation,migration and invasion ability of bladder cancer cells in vitro.The in vivo experiments showed that the tumorigenic ability of ST3Gal4 and ST3Gal6 decreased and the volume of tumor decreased.4.Overexpression of ST3Gal4 and ST3Gal6 inhibited the expression of MMP2,MMP9,AKT,P-S6 K,m TOR and EIF4 B.?.Conclusions1.The expression of ST3Gal4 and ST3Gal6 in bladder cancer tissue is lower than that in normal bladder urothelial tissue.The down-regulation of ST3Gal4 and ST3Gal6 is closely related to the tumor pathological grade.2.ST3Gal4 and ST3Gal6-mediated increase of ?2,3-sialylation can inhibit bladder cancer cells in vitro and in vivo growth,proliferation,migration and invasion ability.3.The effect of ?2,3-sialyltransferase on the malignant behavior of bladder cancer mainly through the PI3K-AKT signaling pathway.