Cilengitide is a potent, selective cyclic RGD peptide and integrin αvβ3/αvβ5 antagonist. It affects FAK/Src/AKT, TGF-β1/Smad, and Ras/ERK/AKT signaling pathways by blocking integrin-mediated signaling, effectively inhibiting tumor cell adhesion, migration, and proliferation, and promoting apoptosis.