Glycoprotein mucin molecular brush on cancer cell surface acting as mechanical barrier against drug delivery

Uptake of cytotoxic drugs by typical tumor cells is limited by the dense dendritic network of oligosaccharide mucin chains that forms a mechanical barrier. Atomic force microscopy is used to directly measure the force needed to pierce the mucin layer to reach the cell surface. Measurements are analyzed by de Gennes' steric reputation theory. Multidrug resistant ovarian tumor cells shows significantly larger penetration load compared to the wide type. A pool of pancreatic, lung, colorectal, and breast cells are also characterized. The chemotherapeutic agent, benzyl-alpha-GalNac, for inhibiting glycosylation is shown to be effective in reducing the mechanical barrier. (C) 2010 American Institute of Physics. [doi:10.1063/1.3532847]