The extracellular matrix (ECM) mediates a wealth of signals to cells dictating their fate. The ECMcomprises mainly proteins and polysaccharides which provide tissue structure and controlcellular functions. It has become evident in the past few decades that perturbations of the ECMprotein composition affect cell behavior (e.g. proliferation, migration and differentiation).However, less attention was given to polysaccharides probably because of a poor understandingof their structural and developmental organization.
Recently the role of sulfated and nonsulfatedpolysaccharides in cell function has started to become more apparent. Particularly,sulfated ECM molecules such as heparan sulfate were reported to play profound roles inproliferation, migration and the phenotype of mammary cells. It is believed that the interactionof sulfated glycosaminoglycans (GAGs) with growth factors such as, the fibroblast growth factor(FGF) family is critical for diverse signaling pathways that modulate cell behavior. Nevertheless,few mechanisms that regulate the action of sulfated molecules have been revealed, whichexplain the reported contradictory roles of heparan sulfate once stating increased proliferationand in others reduced proliferation.
Moreover, most of the studies were carried out in twodimensional(2D) models which often do not recapitulate the actual in vivo environment.The current project aims to unravel the role of sulfated polysaccharides on mammary normaland cancer cell behavior. Because of the difficulty in isolating large quantities of polysaccharideswith identical sulfation patterns, we propose the use of more abundant sugars such as alginateto study the effect of sulfation on mammary cells.
Sulfated alginate has been shown to recognizeand bind heparin-binding growth factors, induce stem cell chondrogenesis, and support theviability of primary hippocampal neurons for up to 21 days. In the current proposal we willsynthesize sulfated alginates at degrees of sulfation (DS) varying from (DS = 0 to 3) and assessthe effect of sulfation degrees on the binding of growth factors relevant for breast cells (e.g. FGFand epidermal growth factor (EGF) among others). We will then determine the effect of thedegree of sulfation on the morphology, proliferation, migration and invasion of breast normaland cancer cells on 2D (tissue culture plastic) and 3D (matrigel) models. We will then comparethe previous results with a novel disease on chip (DOC) model of the ductal mammaryarchitecture which uses hemichannels engraved in polymethylmethacrylate (PMMA).
Finally, wewill assess the effect of sulfated materials in solution or coating nanoparticles onsuppression/induction of the breast cancer phenotype.This highly interdisciplinary project will expand our understanding about the role of cell-ECMinteractions especially sulfated GAGs on growth factor binding and breast normal/canceroustissue development. The significance of this project is emphasized in the sulfation of inherentlynon-sulfated alginate at different degrees of sulfation which is not possible with inherentlysulfated natural ECM GAGs. It will also enable the development of engineered biomimeticmaterials and scaffolds which can be used to treat/diagnose breast cancers.