Poster Presentation 10th Modern Solid Phase Peptide Synthesis & Its Applications Symposium 2025

One-pot synthesis and construction of bispecific bicyclic peptides for integrin-mediated lysosomal targeted protein degradation (129385)

Kwai Man Lau 1 , Terence K. W. Lee 1 , Clarence T. T. Wong 1
  1. Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China

Targeted protein degradation (TPD) via the endosome-lysosome pathway, such as lysosome-targeting chimeras (LYTACs), has emerged as a powerful strategy for eliminating extracellular and membrane proteins.1 Cyclic peptides, with their high cell and tissue permeability, low immunogenicity, and ease of modification, represent ideal scaffolds for designing such degraders.2 In particular, bispecific bicyclic peptides (BBPs) can simultaneously engage cell-surface integrins and target proteins, triggering lysosomal degradation, yet their synthesis remains challenging. To address this, we developed a robust one-pot method for efficient BBP assembly using bis(bromomethyl)benzene-ortho-phthalaldehyde (BBMB-OPA) bifunctional linkers, enabling rapid cyclization of dual-targeting peptides.3 Using this approach, we successfully constructed BBPs against epidermal growth factor receptor (EGFR) and programmed death-ligand 1 (PD-L1). Preliminary Western blot analysis demonstrated up to 50% EGFR degradation in U-87 MG and A549 cells, with further validation underway to confirm integrin- and lysosome-dependent mechanisms. Our work establishes a versatile platform for generating BBPs to modulate membrane proteins, underscoring their therapeutic potential in TPD.

  1. Banik, S. M.; Pedram, K.; Wisnovsky, S.; Ahn, G.; Riley, N. M.; Bertozzi, C. R. Lysosome-Targeting Chimaeras for Degradation of Extracellular Proteins. Nature 2020, 584, 291-297.
  2. Zheng, J.; He, W.; Li, J.; Feng, X.; Li, Y.; Cheng, B.; Zhou, Y.; Li, M.; Liu, K.; Shao, X.; Zhang, J.; Li, H.; Chen, L.; Fang, L. Bifunctional Compounds as Molecular Degraders for Integrin-Facilitated Targeted Protein Degradation. J. Am. Chem. Soc. 2022, 144, 21831-21836.
  3. Shao, C.; Tang, B.; Chu, J. C. H.; Lau, K. M.; Wong, W.-T.; Che, C.-M.; Tai, W. C. S.; Wong, W.-T.; Wong, C. T. T. Macrophage-Engaging Peptidic Bispecific Antibodies (pBsAbs) for Immunotherapy via a Facile Bioconjugation Strategy. Chem. Sci. 2024, 15, 11272.