IRGD peptides

Peptides used in targeted cancer therapy

Overview

iRGD peptides are a class of cyclic peptides that have been engineered to enhance the delivery of therapeutic agents to tumor tissues. These peptides are derived from the C-end rule (CendR) motif, which is characterized by a specific sequence of amino acids that facilitate binding to neuropilin-1 (NRP-1) receptors. The iRGD peptide sequence is typically composed of the integrin-binding motif RGD (Arg-Gly-Asp) followed by a CendR motif, such as R/KXXR/K, where X can be any amino acid.

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Diagram of iRGD peptide structure

Mechanism of Action

The iRGD peptide functions through a multi-step process that enhances the penetration of drugs into tumor tissues. Initially, the RGD motif binds to integrins that are overexpressed on the surface of tumor endothelial cells. This binding facilitates the initial attachment of the peptide to the tumor vasculature. Following this, the peptide undergoes proteolytic cleavage, exposing the CendR motif. The exposed CendR motif then binds to NRP-1 receptors, which are also overexpressed in tumor tissues. This binding triggers a transvascular transport pathway, allowing the peptide and its conjugated therapeutic agents to penetrate deeply into the tumor parenchyma.

Applications in Cancer Therapy

The primary application of iRGD peptides is in the field of cancer therapy, where they are used to improve the delivery and efficacy of chemotherapeutic agents. By enhancing the penetration of drugs into tumors, iRGD peptides can increase the concentration of the drug at the target site, potentially reducing the required dosage and minimizing systemic side effects. iRGD peptides have been studied in combination with various anticancer drugs, including doxorubicin, paclitaxel, and cisplatin.

Advantages and Challenges

The use of iRGD peptides offers several advantages in targeted cancer therapy. These include increased specificity for tumor tissues, improved drug penetration, and the potential for reduced systemic toxicity. However, there are also challenges associated with their use. These include the stability of the peptide in the bloodstream, potential immunogenicity, and the need for precise control over the peptide-drug conjugation process.

Future Directions

Research into iRGD peptides is ongoing, with efforts focused on improving their stability and efficacy. Advances in peptide engineering and nanotechnology are being explored to enhance the delivery capabilities of iRGD peptides. Additionally, there is interest in combining iRGD peptides with other targeting strategies, such as antibody-drug conjugates and nanoparticles, to further improve therapeutic outcomes.

Related Pages

• Peptide therapy
• Targeted drug delivery
• Integrin
• Neuropilin