Summary: Efforts to identify anti-cancer therapeutics and understand tumor-immune interactions are built within vitromodels that do not match the microenvironmental characteristics of human tissues. Usingin vitromodels which mimic the physical properties of healthy or cancerous tissues and a physiologically relevant culture medium, we demonstrate that the chemical and physical properties of the microenvironment regulate the composition and topology of the glycocalyx. Remarkably, we find that cancer and age-related changes in the physical properties of the microenvironment are sufficient to adjust immune surveillance via the topology of the glycocalyx, a previously unknown phenomenon observable only with a physiologically relevant culture medium. Key Points: Culture medium dictates cellular mechanoresponse signatures in vitro Epithelial glycocalyx construction is mediated by Heat Shock Factor 1 (HSF1) Sialic acid topology dictates Natural Killer cell cytotoxicity Physiological microenvironments reveal distinct glycobiology

Efforts to identify anti-cancer therapeutics and understand tumor-immune interactions are built with in vitro models that do not match the microenvironmental characteristics of human tissues. Using in vitro models which mimic the physical properties of healthy or cancerous tissues and a physiologically relevant culture medium, we demonstrate that the chemical and physical properties of the microenvironment regulate the composition and topology of the glycocalyx. Remarkably, we find that cancer and age-related changes in the physical properties of the microenvironment are sufficient to adjust immune surveillance via the topology of the glycocalyx, a previously unknown phenomenon observable only with a physiologically relevant culture medium.