Download MendeleyAn engineered yeast cytosine deaminase with improved catalytic activity and stability for macrophage-mediated enzyme/prodrug therapy.
Zheng, J., Zhou, J., Yung, K.W.Y., Hu, Q., Lee, M.M., Chan, M.K.(2025) Commun Biol 8: 1562-1562
- PubMed: 41233498
- DOI: https://doi.org/10.1038/s42003-025-08931-x
- Primary Citation of Related Structures:
9K1K - PubMed Abstract:
Utilization of yeast cytosine deaminase (yCD) to activate the prodrug 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU) at the target site is an attractive strategy for overcoming the narrow therapeutic index of 5-FU. Nevertheless, protein delivery of yCD is challenging in part due to its thermal instability. Herein, we have rationally engineered a mutant yCD by replacing Met100 situated at the active site entry with the bulkier histidine to hinder potential oxidation of the active site Cys91. The engineered yCD-Met100His exhibits significantly enhanced activity and thermal stability. yCD-M100H is then genetically fused to the crystal-forming protein Cry3Aa to generate Cry3Aa-yCD-M100H fusion crystals to facilitate the enzyme's uptake into macrophages. The resulting Cry3Aa-yCD-M100H-loaded macrophages exhibit excellent penetration into tumor spheroids and readily convert 5-FC to 5-FU leading to efficacious cancer cell killing. This study showcases a promising route for stabilizing yCD and the feasibility of enzyme-internalized macrophages to serve as tumor-specific enzyme/prodrug activators.
- School of Life Sciences and Center of Novel Biomaterials, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
Organizational Affiliation:
