The RGD peptide is the binding motif of fibronectin to cell adhesion molecules. RGD peptide acts as an inhibitor of integrin-ligand interactions and can induce apoptosis in the absence of signals and integrin-mediated cell clustering. Research demonstrates that RGD peptides promote apoptosis through activation of conformation changes that enhance pro-caspase-3 activation and autoprocessing. The RGD peptide can serve as a cell adhesion site of extracellular matrix, cell surface proteins, and integrins. In addition, RGD peptide can inhibit ACK-2 activation through cell adhesion.