Integrin-driven differences in extracellular matrix regulation of 3D-cultured tumor cells

Table 1 Properties of integrins and their involvement in cell-extracellular matrix interactions among other cell adhesion molecules

	Integrins	Selectins	Ig superfamily cell adhesion molecules (ICAMs)
Cation dependence	Require divalent cations (Ca2+, Mg2+, Mn2+)	Require Ca2+	Independent of Ca2+
Ligand type	Bind ECM proteins or counter-receptors (e.g., ICAMs)	Bind carbohydrate ligands	Bind protein ligands (e.g., integrins)
Adhesion type	Cell-matrix and cell-cell	Transient cell-cell (rolling)	Stable cell-cell
Specific types involved into ECM-cell interactions	RGD-binding integrins, laminin-binding integrins, collagen-binding integrins, leukocyte-specific integrins	Specific selections can interact with integrins, facilitating cell adhesion and signaling	Some ICAMs can bind to integrins

ECM: Extracellular matrix; RGD: Arg-Gly-Asp; ICAMs: Intercellular adhesion molecules.