The role of sialylation in gynecologic cancers.

Abstract

Sialic acids (SA) are a kind of nine-carbon backbone sugars, serving as important molecules in cell-to-cell or cell-to-extra-cellular matrix interaction mediated by either O-linked glycosylation or N-linked glycosylation to attach the terminal end of glycans, glycoproteins, and glycolipids. All processes need a balance between sialylation by sialyltransferase (STs) and desialylation by sialidases (also known as neuraminidases, NEU). Although there is much in uncertainty whether the sialyation plays in cancer development and progression, at least four mechanisms are proposed, including surveillance of immune system, modification of cellular apoptosis and cell death, alteration of cellular surface of cancer cells and tumor associated microenvironment responsible carcinogenesis, growth and metastases. The current review focuses on the role of glycosylation in gynecologic organ-related cancers, such as ovarian cancer, cervical and endometrial cancer. Evidence shows that sialylation involving in the alternation of surface components of cells (tumor and cells in the microenvironment of host) plays an important role for carcinogenesis (escape from immunosurveillance) and dissemination (metastasis) (sloughing from the original site of cancer, migration into the circulation system, extravasation from the circulatory system to the distant site and finally deposition and establishment on the new growth lesion to complete the metastatic process). Additionally, modification of glycosylation can enhance or alleviate the aggressive characteristics of the cancer behaviors. All suggest that more understandings of glycosylation on cancers may provide a new therapeutic field to assist the cancer treatment in the near future.