The Roles of Integrin α5β1 in Human Cancer

Cell adhesion to the extracellular matrix has important roles in tissue integrity and human health. Integrins are heterodimeric cell surface receptors that are composed by two non-covalently linked alpha and beta subunits that mainly participate in the interaction of cell-cell adhesion and cell-extracellular matrix and regulate cell motility, adhesion, differentiation, migration, proliferation, etc. In mammals, there have been eighteen alpha subunits and 8 beta subunits and so far 24 distinct types of alpha beta integrin heterodimers have been identified in humans. Integrin alpha 5 beta 1, also known as the fibronectin receptor, is a heterodimer with alpha 5 and beta 1 subunits and has emerged as an essential mediator in many human carcinomas. Integrin alpha 5 beta 1 alteration is closely linked to the progression of several types of human cancers, including cell proliferation, angiogenesis, tumor metastasis, and cancerogenesis. In this review, we will introduce the functions of integrin alpha 5 beta 1 in cancer progression and also explore its regulatory mechanisms. Additionally, the potential clinical applications as a target for cancer imaging and therapy are discussed. Collectively, the information reviewed here may increase the understanding of integrin alpha 5 beta 1 as a potential therapeutic target for cancer.