Invadopodia formation on nanometer scale protein patterns

Abstract

How the positions of invadopodium in the cell are determined and if they have an adhesivefunction are not known. Using fluorescence microscopy and antibodies that recognize actin, cortactin and MT1-MMP proteins, invadopodia formed by breast cancer cells plated on protein nanopatterns of different geometeries and components after stimulation with epidermal growth factor which is known to induce invadopodia formation, were examined. Invadopodia formation was studied for the first time on nanometer scale, single and double active component, protein patterns with equal distance and gradient spacings. The results show that: • On K-casein-fibronectin nanopatterns, invadopodia prefer to form on K-casein which blocks cell adhesion rather than on fibronectin nanodots which promote cell adhesion. • On Laminin-fibronectin nanopatterns, invadopodia prefer to form on laminin rather than on fibronectin nanodots. • On gradient patterns, invadopodia prefer areas with wide spacings. These results support the hypotheses that the positions where invadopodia form can be determined by surface protein nanopatterns and that cell adhesion is not required at points where invadopodia will form.