The Relationship Of Lipopolysaccharide With Abnormal O-glycosylation Of Colon Cancer

Objective:To investigatethe epigenetics relationship of Lipopoly-saccharide with abnormal O-glycosylation of colon cancer through analyze the effect of Lipopolysaccharide on the mRNA expression level of DNMTs、Cosmc、T-synthase and the methylation status of Cosmc gene in the colon cancer cell lines which expression Tn antigen.Methods:The Tn(-)、Tn(+) colon cancer cell lines LSC were cultured with different concentration of LPS for48hours,respectively. Cell immunofluorescence was used to detected the expression of Tn antigen in Tn(-) and Tn(+) cell lines.mRNA expression levels of DNMTs、Cosmc、T-synthase were measured using Real-time PCR. Then Methylation-specific PCR was performed to test the promoter methylation of Cosmc.Results:(1) Tn(-) cells express small amounts of Tn antigen, the expression of Tn antigen in Tn(-)、Tn(+)cells lines were increased after stimulated with LPS,especially in Tn(+);The expression of Tn antigen in Tn(+) cell lines was significantly higher than Tn(-) cell lines.(2)The mRNA expression level of Cosmc gene in Tn(-)、Tn(+)cells lines were decreased dramatically after LPS treated,and had statistics significance between each subgroups. The expression of T-synthase in two cell lines decreased with the increasing concentration of LPS,but in Tn(-) cell there has significant differences between each groups,while in Tn(+) cell lines there has no significant statistics significance between100ng/ml LPS group and1μg/ml LPS group.(3) The expression levels of DNMT1in Tn(-) and Tn(+) cell lines were increased with or without LPS stimulated,but in Tn(-) cells there was no significant differences between each groups(P>0.05),while in Tn(+) cell lines there has significant statistics significance between the untreated group and1μg/ml LPS group;the expression levels of DNMT3a and DNMT3b in two cell lines of each subgroup had statistics significance before and after the stimulation of LPS(p<0.01),and the expression levels increased with the increasing concentration of LPS.(4) CpG islands of Cosmc gene promoters from Tn(-) cell, Tn(+) cell and different concentration of LPS stimulated groups were partially methylated.Conclusion:The expression level of Tn antigen in colon cancer cell line were increased with LPS concentration, the reason may be related to LPS cause DNMTs abnormal expression then promoting Cosmc gene promoter methylation.