Extracellular matrix sulfation in the tumor microenvironment stimulates cancer stemness and invasiveness

Tumor extracellular matrices (ECM) exhibit aberrant changes in composition and mechanics compared to normal tissues. Proteoglycans (PG) are vital regulators of cellular signaling in the ECM with ability to modulate receptor tyrosine kinase (RTK) activation via their sulfated glycosaminoglycan (sGAG) side chains. However, their role on tumor cell behavior is controversial. Here, we demonstrate that PGs are heavily expressed in lung adenocarcinoma patients in correlation with invasive phenotype and poor prognosis. We developed an engineered human lung tumor model which recapitulate the increase of sGAGs in tumors in an organotypic matrix with independent control of stiffness, viscoelasticity, ligand density and porosity. Our model reveals that increased sulfation stimulates extensive proliferation, epithelial-mesenchymal transition and stemness in cancer cells. We identified the FAK-PI3K-Akt signaling axis as a mediator of sulfation-induced molecular changes in cells upon activation of a distinct set of RTKs within tumor-mimetic hydrogels. We employed an integrative omics and network modeling approach to uncover the transcriptomic landscape of tumor cells in response to sulfation which demonstrated resemblance to PG-rich patient tumors.