Alpha5 integrin dependent 3D attachment, appearance, and migration (Not 2D) (cell-derived) (pliable)
Some early studies in 3-Dimensional Substrates: Bissell lab HMT-3522 Breast Epithelial cells –S-1: nonmalignant –T4-2: tumorigenic Grown on plastic: 2 cell lines appear similar Grown in reconstituted basement membrane (rBM): – S-1 cells form polarized, acinar structures in growth arrest –T4-2 cells form nonpolarized, proliferating amorphous structures
On 2D substrates: cells have fully mature focal contacts. In 3D substrates: clustered integrins couple to less-completely assembled focal interations and a predominantly cortical actin cytoskeleton; stress fiber formation is rare.
The abrogation of beta1 integrin function can generate single-cell dissemination. Insert movie with melanoma explants
HT-1080 and MDA-MB-231 cells remain migratory after pericellular proteolysis: compensation by mesenchymal-amoeboid transition. First insert videos from this paper Now insert dermis/ SQ video Green = not treated Red = pretreated with PIs
Elongated, spindle-shaped Beta1 integrin dependent ECM-degrading enzymes colocalize with integrins Reduced elongation Increased morphodynamic flexibility Loss of focal beta1 integrin and MMP clustering at interactions with ECM Less adhesion to collagens (lower 1 & B3 More diffuse cortical actin distribution Lymphocytes Neutrophils
Role of Rho family of GTPases In Mesenchymal-Amoeboid Transition
Effect of Rho and ROCK inhibitors on cells with a rounded vs. elongated Phenotype - invasion into matrigel Only rounded cells show a decrease in migration when treated.