RGD-Binding Integrins Revisited: How Recently Discovered Functions and Novel Synthetic Ligands (Re-)Shape an Ever-Evolving Field

• Published in: Cancers Vol. 13; no. 7; p. 1711
• Main Authors: Ludwig, Beatrice S, Kessler, Horst, Kossatz, Susanne, Reuning, Ute
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.04.2021; MDPI
• Subjects: Amino acids; Angiogenesis; Breast cancer; Cancer; Cell adhesion; Cell adhesion & migration; Cell surface; Clinical trials; Coronaviruses; Crystal structure; Exosomes; Fibrosis; Growth factors; Integrins; Kinases; Ligands; Lung cancer; Metastases; Metastasis; Proteins; Review; Sepsis; Severe acute respiratory syndrome coronavirus 2; Signal transduction; Therapeutic applications; Therapeutic targets; Wound healing; SARS-CoV-2; synthetic integrin ligands; RGD-binding integrins; angiogenesis; exosomes; αvβ6; αvβ3; integrin targeted therapy; molecular imaging; vascular normalization therapy
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers13071711

Integrins have been extensively investigated as therapeutic targets over the last decades, which has been inspired by their multiple functions in cancer progression, metastasis, and angiogenesis as well as a continuously expanding number of other diseases, e.g., sepsis, fibrosis, and viral infections, possibly also Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). Although integrin-targeted (cancer) therapy trials did not meet the high expectations yet, integrins are still valid and promising targets due to their elevated expression and surface accessibility on diseased cells. Thus, for the future successful clinical translation of integrin-targeted compounds, revisited and innovative treatment strategies have to be explored based on accumulated knowledge of integrin biology. For this, refined approaches are demanded aiming at alternative and improved preclinical models, optimized selectivity and pharmacological properties of integrin ligands, as well as more sophisticated treatment protocols considering dose fine-tuning of compounds. Moreover, integrin ligands exert high accuracy in disease monitoring as diagnostic molecular imaging tools, enabling patient selection for individualized integrin-targeted therapy. The present review comprehensively analyzes the state-of-the-art knowledge on the roles of RGD-binding integrin subtypes in cancer and non-cancerous diseases and outlines the latest achievements in the design and development of synthetic ligands and their application in biomedical, translational, and molecular imaging approaches. Indeed, substantial progress has already been made, including advanced ligand designs, numerous elaborated pre-clinical and first-in-human studies, while the discovery of novel applications for integrin ligands remains to be explored.