Decorin from different bovine tissues: study of glycosaminoglycan chain by PAGEFS

The sulphation pattern of glycosaminoglycan (GAG) plays a critical role in biological functions of proteoglycans. In this study, we showed that decorins from different bovine tissues present specific sulphation pattern coupled with peculiar biological activity. In order to elucidate chemical structure of decorin glycosaminoglycan chains, we improved an electrophoretic method to analyse fluorescent disaccharides from dermatan/chondroitin sulphate GAG chains. The disaccharide separation is based on minigels, and this technique was able to define the polysaccharide chain composition in terms of sulphated and not sulphated disaccharides. This approach allowed not only the measurement of few picomoles of material, but it also permits a rapid qualitative analysis of the GAG chains. Data obtained by PAGEFS indicate that the sulphation pattern of GAG is tissue specific and this finding may explain the different binding properties to von Willebrand factor of decorins

Glycosaminoglycans: key players in cancer cell biology and treatment

Glycosaminoglycans are natural heteropolysaccharides that are present in every mammalian tissue. They are composed of repeating disaccharide units that consist of either sulfated or non-sulfated monosaccharides. Their molecular size and the sulfation type vary depending on the tissue, and their state either as part of proteoglycan or as free chains. In this regard, glycosami-noglycans play important roles in physiological and pathological conditions. During recent years, cell biology studies have revealed that glycosaminoglycans are among the key macromolecules that affect cell properties and functions, acting directly on cell receptors or via interactions with growth factors. The accumulated knowledge regarding the altered structure of glycosaminoglycans in several diseases indicates their importance as biomarkers for disease diagnosis and progression, as well as pharmacological targets. This review summarizes how the fine structural characteristics of glycosaminoglycans, and enzymes involved in their biosynthesis and degradation, are involved in cell signaling, cell function and cancer progression. Prospects for glycosaminoglycan-based therapeutic targeting in cancer are also discussed

MDA-MB-231 breast cancer cell viability, motility and matrix adhesion are regulated by a complex interplay of heparan sulfate, chondroitin-/dermatan sulfate and hyaluronan biosynthesis

Proteoglycans and glycosaminoglycans modulate numerous cellular processes relevant to tumour progression, including cell proliferation, cell-matrix interactions, cell motility and invasive growth. Among the glycosaminoglycans with a well-documented role in tumour progression are heparan sulphate, chondroitin/dermatan sulphate and hyaluronic acid/hyaluronan. While the mode of biosynthesis differs for sulphated glycosaminoglycans, which are synthesised in the ER and Golgi compartments, and hyaluronan, which is synthesized at the plasma membrane, these polysaccharides partially compete for common substrates. In this study, we employed a siRNA knockdown approach for heparan sulphate (EXT1) and heparan/chondroitin/dermatan sulphate-biosynthetic enzymes (\u3b24GalT7) in the aggressive human breast cancer cell line MDA-MB-231 to study the impact on cell behaviour and hyaluronan biosynthesis. Knockdown of \u3b24GalT7 expression resulted in a decrease in cell viability, motility and adhesion to fibronectin, while these parameters were unchanged in EXT1-silenced cells. Importantly, these changes were associated with a decreased expression of syndecan-1, decreased signalling response to HGF and an increase in the synthesis of hyaluronan, due to an upregulation of the hyaluronan synthases HAS2 and HAS3. Interestingly, EXT1-depleted cells showed a downregulation of the UDP-sugar transporter SLC35D1, whereas SLC35D2 was downregulated in \u3b24GalT7-depleted cells, indicating an intricate regulatory network that connects all glycosaminoglycans synthesis. The results of our in vitro study suggest that a modulation of breast cancer cell behaviour via interference with heparan sulphate biosynthesis may result in a compensatory upregulation of hyaluronan biosynthesis. These findings have important implications for the development of glycosaminoglycan-targeted therapeutic approaches for malignant diseases