Sialyltransferase in Breast Cancer

摘要

Alterations in sialylation are well documented in breast cancer as well as other epithelial cancers. A principal enzyme implicated in this process is the sialyltransferase ST6Gal, which mediates the synthesis of the sialyl a2, 6-anomeric linkage to terminal lactosamine structures on glycoproteins, and high levels have been linked to a poor prognosis especially among patients with locally advanced stage Ill breast cancer. Transcription of the ST6Gal - gene is regulated by selective use of multiple promoters in a tissue- and developmental- specific manner. We documented the existence of a breast-specific promoter that is recruited de novo to allow high ST6Gal gene expression during late pregnancy and lactation in mouse mammary glands. However we failed to detect an equivalent breast-specific promoter operative in humans. Examination in a number of murine breast cancer models also failed to detect recruitment of this promoter in ST6Gal expression.