1. Affibody-conjugated 5-fluorouracil prodrug system preferentially targets and inhibits HER2-expressing cancer cells
- Author
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Keng Hsueh Lan, Keng Li Lan, Cheng-Liang Tsai, Yu-Yi Chen, Tun-Ling Lee, Yee Chao, and Chiung-Wen Pai
- Subjects
Scaffold protein ,Saccharomyces cerevisiae Proteins ,Angiogenesis ,Receptor, ErbB-2 ,Recombinant Fusion Proteins ,Biophysics ,Flucytosine ,Gene Expression ,Antineoplastic Agents ,Biochemistry ,Metastasis ,Cytosine Deaminase ,Inhibitory Concentration 50 ,Cell Line, Tumor ,medicine ,Humans ,Prodrugs ,Amino Acid Sequence ,Molecular Targeted Therapy ,skin and connective tissue diseases ,neoplasms ,Molecular Biology ,Biotransformation ,Chemistry ,Cytosine deaminase ,Cancer ,Cell Biology ,Prodrug ,medicine.disease ,Fusion protein ,Cancer cell ,Cancer research ,Fluorouracil ,Protein Binding - Abstract
Overexpression of HER2 is associated with cancer phenotypes, such as proliferation, survival, metastasis and angiogenesis, and has been validated as a therapeutic target. However, only a portion of patients benefited from anti-HER2 treatments, and many would develop resistance. A more effective HER2 targeted therapeutics is needed. Here, we adopted a prodrug system that uses 5-fluorocytosine (5-FC) and a HER2-targeting scaffold protein, ZHER2:2891, fused with yeast cytosine deaminase (Fcy) to target HER2-overexpressing cancer cells and to convert 5-FC to a significantly more toxic chemotherapeutic, 5-fluorouracil (5-FU). We cloned the coding gene of ZHER2:2891 and fused with those of ABD (albumin-binding domain) and Fcy. The purified ZHER2:2891-ABD-Fcy fusion protein specifically binds to HER2 with a Kd value of 1.6 nM ZHER2:2891-ABD-Fcy binds to MDA-MB-468, SKOV-3, BT474, and MC38-HER2 cells, which overexpress HER2, whereas with a lower affinity to HER2 non-expresser, MC38. Correspondingly, the viability of HER2-expressing cells was suppressed by relative low concentrations of ZHER2:2891-ABD-Fcy in the presence of 5-FC, and the IC50 values of ZHER2:2891-ABD-Fcy for HER2 high-expresser cells were approximately 10–1000 fold lower than those of non-HER2-targeting Fcy, and ABD-Fcy. This novel prodrug system, ZHER2:2891-ABD-Fcy/5-FC, might become a promising addition to the existing class of therapeutics specifically target HER2-expressing cancers.
- Published
- 2021