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Author
Alonso Martí, Anna
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Abstract
The presence of an abundant extracellular matrix (ECM), composed mainly of collagen, proteoglycans, and hyaluronic acid, is one of the distinguishing features of several solid tumors.
This ECM acts as a physical barrier, preventing the entry of drugs and other chemotherapeutic agents. With the support of a multi-protein assembly that comprises the well-known focal adhesions, the extracellular matrix can be physically linked to the actin cytoskeleton, facilitating cell signaling and transduction related to growth control. Several model studies have been conducted to investigate cell behavior and to study those components related to cell-matrix adhesion. However, it has been demonstrated that 2D cultures do not reproduce the physiological environment in which cells grow. A major advance in cell culture techniques has been the implementation of three-dimensional (3D) culture systems. These 3D cultures are more closely related to the in vivo cellular environment by creating an artificial ECM that facilitates cell-cell and cell-matrix interactions, allowing the study of cell migration, growth, and differentiation. To examine whether treatment with collagenase, an enzyme that can cleave collagen in specific areas, can provide improvements in extracellular membrane degradation, cultures of cancer cell lines (PANC-1 and MiaPaCa-2) as well as primary normal fibroblast cells (hNDF) were treated with type I collagenase. Analysis of components of the focal adhesion complex demonstrated the degradation of focal adhesion kinase (FAK), a key protein involved in the mechano-signaling process. Although different degradation pathways have been discarded using specific inhibitors, how FAK is degraded remains unknown. On the other hand, at the phenotypic level, collagenase treatment has been shown to promote a dramatic cellular shape transition consisting in rounding of cultured cells on top of collagen filaments, which involves a complex and organized cell migration that ends in the formation of a defined cellular cluster.
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