The Functional Role of Extracellular Matrix Proteins in Cancer

SIMPLE SUMMARY: Extracellular matrix is a three-dimensional network of macromolecules that provide structural and biochemical support to surrounding cells. Extracellular matrix plays a critical role in the development and progression of cancer. The extracellular matrix of the tumor is very different from the matrix of the normal tissue. Mainly fibroblasts produce and regulate matrix remodeling, but in cancer, the tumor matrix also originates from cancer cells. We describe the mechanisms of how the protein composition and structure of the extracellular matrix changes during cancer progression and how abnormal matrix deregulates the behavior of stromal cells and influences cancer progression. ABSTRACT: The extracellular matrix (ECM) is highly dynamic as it is constantly deposited, remodeled and degraded to maintain tissue homeostasis. ECM is a major structural component of the tumor microenvironment, and cancer development and progression require its extensive reorganization. Cancerized ECM is biochemically different in its composition and is stiffer compared to normal ECM. The abnormal ECM affects cancer progression by directly promoting cell proliferation, survival, migration and differentiation. The restructured extracellular matrix and its degradation fragments (matrikines) also modulate the signaling cascades mediated by the interaction with cell-surface receptors, deregulate the stromal cell behavior and lead to emergence of an oncogenic microenvironment. Here, we summarize the current state of understanding how the composition and structure of ECM changes during cancer progression. We also describe the functional role of key proteins, especially tenascin C and fibronectin, and signaling molecules involved in the formation of the tumor microenvironment, as well as the signaling pathways that they activate in cancer cells.