An Overview of Radiolabeled RGD Peptides for Theranostic Applications.

Angiogenesis phenomenon, as a highly affecting factor on the growth and spread of cancer cells, depends on specific molecular interactions between components of the extracellular matrix and vascular cells. αv integrin acts as a cell adhesive molecule involved in tumor invasion and angiogenesis. Among the various combinations of integrin subunits expressed on the surface of cells, α_vβ₃ integrin has a particularly interesting expression pattern during angiogenesis. The α_vβ₃ integrin is a vital receptor affecting tumor growth, tumor invasiveness, metastasis, and angiogenesis overexpressed on various human tumors, leading to the development of different theranostics probes and radiopharmaceuticals. The α_vβ₃ integrin can recognize several extracellular matrix molecules in the base of the RGD adhesive sequence. This review provides an overview of the status, trends and future of the most studied α_vβ₃ integrin-binding ligand, RGD tripeptides, labeled with various radioisotopes. An overview of the pre-clinical models for radiolabeled RGD peptides and clinical aspects of the RGD- based radiopharmaceuticals is provided with some new considerations and ways forward.