Cyclic Peptides as Drugs for Intracellular Targets: The Next Frontier in Peptide Therapeutic Development

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Drug Discovery

Background:

• Developing macrocyclic peptides for intracellular targets presents significant challenges.
• Traditional physical properties are inadequate for predicting cell membrane permeability in macrocyclic peptides.
• Peptide synthesis and experimental permeability assays are crucial for differentiating cell-permeable molecules.

Purpose of the Study:

• To review recent strategies for developing cell-permeable cyclic peptides.
• To identify methods that maintain target binding affinity intracellularly.
• To highlight effective approaches for overcoming cell permeability barriers.

Main Methods:

• Review of chemical strategies for peptide modification.
• Analysis of backbone N-methylation and stereochemical changes.
• Evaluation of side-chain alteration techniques.

Main Results:

• Backbone modifications (N-methylation, stereochemical changes) improve cell permeability but can reduce biological activity.
• Chemical modifications often alter peptide conformation, affecting target binding.
• Side-chain alterations show promise for enhancing cell permeability without impacting target binding.

Conclusions:

• Optimizing macrocyclic peptides for intracellular delivery requires careful consideration of permeability and activity.
• Side-chain modifications represent a promising strategy for developing effective cell-permeable peptides.
• Future research should focus on refining side-chain alteration techniques to maximize therapeutic potential.