This study presents a novel strategy to address the long-standing challenge of targeted degradation of membrane-bound cancer-associated proteins. By designing phase-separable lysosome-targeting peptide coacervates, it achieves efficient intracellular delivery and lysosomal localization of antibody-antigen complexes, offering a scalable technical platform for tumor immunotherapy and targeted protein degradation.
Literature Overview
The article titled 'Coacervate-Mediated Lysosome-Targeting Antibody Delivery for Protein Degradation,' published in the journal Advanced Science, systematically explores how peptide-based coacervates formed via liquid-liquid phase separation (LLPS) can enable antibody-mediated lysosomal degradation of membrane proteins. The authors developed a lysosome-sorting peptide coacervate named LSP-Coa, capable of spontaneously entering cells and targeting lysosomes, thereby promoting the degradation of antibody-antigen complexes. This strategy, termed CoaLPD (Coacervate-mediated Lysosome-targeting Protein Degradation), demonstrates efficient degradation of HER2 and EGFR both in vitro and in vivo.Background Knowledge
Targeted protein degradation (TPD) has become a pivotal direction in anticancer therapy. While PROTACs rely on the ubiquitin-proteasome system, technologies such as LYTAC exploit the lysosomal pathway to degrade extracellular or membrane proteins. However, LYTAC depends on the expression levels of cell surface receptors (e.g., LTR, ASGPR, TfR), limiting its broad applicability. Furthermore, transmembrane delivery of antibody-antigen complexes and lysosomal targeting remain key bottlenecks. Many cancer-associated proteins (CAPs), such as HER2 and EGFR, are membrane proteins; traditional small-molecule inhibitors often lead to drug resistance, and existing degradation technologies struggle with efficient delivery of large macromolecular complexes. Thus, developing a universal delivery system independent of specific receptors is urgently needed. This study proposes a receptor-independent delivery strategy based on the membrane-permeable properties of phase-separating coacervates combined with lysosome-targeting sequences, precisely addressing the dual challenges of lysosomal targeting and transmembrane delivery.
Research Methods and Experiments
The authors designed two phase-separating peptides, LSP1 and LSP2, based on a 'stick-spacer' model, selecting LSP2 for further study due to its lower cytotoxicity. LSP2 forms microdroplets in PBS via liquid-liquid phase separation, exhibiting typical liquid behaviors such as spontaneous fusion and rapid fluorescence recovery after photobleaching. Using the SK-BR-3 cell line (high HER2 expression) as the primary model, they demonstrated that LSP-Coa efficiently encapsulates proteins and enters cells, co-localizing with the lysosomal marker LysoTracker. Confocal microscopy and Western blot analysis confirmed that LSP-Coa delivers Trastuzumab-LSP or Cetuximab-LSP complexes into cells, significantly degrading HER2 and EGFR. Additionally, the system enhanced cellular uptake and degradation efficiency of a PROTAC molecule.Key Conclusions and Perspectives
Research Significance and Prospects
This study overcomes the receptor expression dependency of traditional LYTACs by introducing a universal lysosome-targeting delivery system, greatly expanding the range of targetable membrane proteins. As a programmable carrier, LSP-Coa is not only suitable for antibody-antigen complexes but also applicable for delivering other macromolecular therapeutics, offering a new tool for targeted therapy. Its significant antitumor effects in vivo indicate strong clinical translational potential, particularly for malignancies such as HER2+ breast cancer and EGFR+ lung cancer.
Moreover, this platform can be combined with existing degradation technologies (e.g., PROTACs) to achieve synergistic enhancement, enabling multi-mechanistic combination therapies. Future studies could explore optimization of different lysosome-targeting sequences, tissue-specific modifications, and large-scale production feasibility, further advancing clinical translation. This strategy also offers new insights for degrading other challenging membrane receptors, such as PD-L1 and c-MET.
Conclusion
The LSP-Coa coacervate platform developed in this study successfully achieves lysosome-targeted degradation of membrane proteins via antibody mediation, introducing a novel receptor-independent targeted protein degradation strategy—CoaLPD. This technology not only efficiently degrades HER2 and EGFR but also significantly suppresses tumor growth in animal models, demonstrating robust anticancer potential. Its core advantage lies in combining efficient transmembrane delivery with precise lysosomal targeting, solving the dual challenges of macromolecular delivery and degradation pathway control in current targeted therapies. From bench to bedside, this platform offers a new paradigm for precision treatment of solid tumors such as breast and lung cancers, particularly providing new avenues for intervention in drug-resistant tumors. Combined with Cyagen’s comprehensive support in gene-editing animal models and pharmacological evaluation, preclinical validation and translational research of this technology can be accelerated, potentially establishing it as a cornerstone of next-generation targeted protein degradation therapies.
