Functional studies on sulphation status of heparan sulphate in breast non-tumourigenic epithelial and cancer cells

Abstract

Heparan sulphate, a widely distributed glucosaminoglycan, is known to interact with numerous signaling molecules. This thesis investigated the effects of heparan sulphation on breast non-tumourigenic epithelial and cancer cells. Inhibiting heparan sulphation in breast cancer cells resulted in decreased cell proliferation, cell cycling, migration and invasion, together with an increase in cell adhesion. Real-time PCR examination of four different breast cancer cell lines showed consistent down regulation of HS3ST3A1, which encodes a sulphotransferase that adds sulphate groups to heparan sulphate. When HS3ST3A1 was silenced in non-tumourigenic breast epithelial cells, the cells became less adhesive, and showed increased mobility and invasiveness. Gene expression profiling using high density oligonucleotide microarrays revealed differential expression of 186 genes after silencing HS3ST3A1, some of which are known to be involved in regulating cell cycle and cell-matrix interaction. Taken together, these experiments underline the importance of sulphation status of heparin sulphate in regulating cellular behavior.