Cosmc transfection decreases malignant behavior of Tn(+) cells and enhances sensitivity to apoptosis when induced by Apo2L/TRAIL via alteration of O-glycan structure

Cosmc mutations may cause abnormal O-glycosylation and result in Tn antigen expression. In the current study, it was discovered that proliferation and migration of Tn+ cells (Jurkat T and LS174T-Tn(+) cells) with mutant Cosmc decreased after transfected Cosmc, and their sensitivity to apoptosis induced by Apo2L/TRAIL increased. Core 1-, 2-, and 3-derived O-glycans were absent in Tn(+) cells. After Cosmc transfection, normal extended core 1-derived O-glycans appeared and were accompanied by increased T-synthase activity. Core 2-derived O-glycans appeared in transfected LS174T-Tn(+) cells, and their structural types and levels were lower than those in LS174T-Tn(−) cells. Core 3-derived O-glycans were present only in LS174T-Tn(−) cells. The activity of C3GnT in LS174T-Tn(+) cells was lower than that in LS174T-Tn(−) cells, and it was absent in Jurkat T cells. Cosmc transfection did not alter C3GnT activity or core 3-derived O-glycans in Jurkat T and LS174T-Tn(+) cells. The results demonstrated that the composition and structure of O-glycans were different among various Tn(+) cells, which not only affected cell malignant behavior but also modulated sensitivity to apoptotic stimuli. Thus, Cosmc transfection may effectively decrease the malignant behavior of Tn(+) tumor cells and enhance their sensitivity to apoptosis when induced by Apo2L/TRAIL through modification of O-glycans.