Sugars and cell adhesion: the role of ST6GalNAc1 in prostate cancer progression

O-linked glycans become altered in cancer cells, leading to changes in cell adhesive properties and contributing to metastasis. But the mechanisms driving these changes and how these carbohydrate groups are involved in tumour spread remain poorly understood. We recently identified the sialyltransferase gene ST6GalNAc1 as a novel androgen-regulated gene in prostate cancer. Expression of ST6GalNAc1 in prostate cancer cells induced expression of the cancer-associated sTn antigen, reduced cell adhesion, and dramatically inhibited the formation of stable tumour masses in vivo after orthotopic transplantation experiments in mice. Although ST6GalNAc1 is significantly upregulated in primary prostate carcinoma tissue, there is a striking downregulation of this gene in metastatic prostate tissue, suggesting an important yet transient role for ST6GalNAc1 in prostate cancer progression. Here we discuss mechanistically how changes in sialylation could alter prostate tumour cell behaviour and contribute to cancer cell dissemination.