Ovarian and cervical cancers are the most common causes of cancer death from gynecologic tumors in the world. The cancer antigen CA215 was initially identified by RP215, a monoclonal antibody that was originally generated against OC-3-VGH ovarian cancer cells. With RP215 as the probe, CA215 was determined to be a widespread cancer marker and was detected in many different human cancer tissues. Significant elevation of CA215 in serum was found in patients with ovarian and cervical cancers. Since RP215 was shown to react with carbohydrate-associated epitope(s) on CA215, we used highly purified CA215 isolated from both ovarian and cervical cancer cells and carried out O-glycan structural characterization through MALDI-TOF mass spectrometry, lectin-staining and immunohistochemical analysis. The common O-glycan cores 1 to 4 have been observed, as well as mono-fucosylated and di-fucosylated core 1 to 3 based structures. The predominant structures carried by CA215 were sialyl-T, sialyl-Tn and di-sialyl-T antigens. Epitopes such as Lea, Leb, Lex, Ley and SLex were found. Furthermore, the potential pathways for synthesizing CA215 carbohydrate-associated epitope(s) in ovarian and cervical cancer cell lines have been elucidated based on the study of glycosyltransferases involved in O-glycan synthesis. The biosynthetic pathways of mucin type O-glycans in ovarian and cervical cancer cells are similar to a selected number of prostate cancer cells. These results are the foundation for the development of glycosyltransferase targets, effective anti-cancer vaccines and RP215-based anti-cancer drugs in humans.

Structures of carbohydrate-associated epitope on CA215 expressed in ovarian and cervical cancer cell lines and proposed biosynthetic pathways

244th National Meeting (2012)

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