Targeted antitumor prodrug therapy using CNGRC-yCD fusion protein in combination with 5-fluorocytosine.
J Biomed Sci
; 23: 15, 2016 Jan 22.
Article
em En
| MEDLINE
| ID: mdl-26801910
ABSTRACT
BACKGROUND:
The enzyme-prodrug system is considered a promising tool for tumor treatment when conjugated with a targeting molecule. The asparagine-glycine-arginine (NGR) motif is a developing and interesting targeting peptide that could specifically bind to aminopeptidase N (APN), which is an NGR receptor expressed on the cell membrane of angiogenic endothelial cells and a number of tumor cells within the tumor tissues. The objective of this study was to develop a novel targeted enzyme-prodrug system using 5-fluorocytosine (5-FC) and an NGR-containing peptide fused with yeast cytosine deaminase (yCD), i.e. CNGRC-yCD fusion protein, to target APN-expressing cells within the tumor tissues and to convert 5-FC into 5-fluorouracil (5-FU) to kill tumors.RESULTS:
Both yCD and CNGRC-yCD proteins were cloned into the pET28a vector and expressed by an Escherichia coli host. Both yCD and CNGRC-yCD proteins were purified and the yields were approximately 20 mg/L with over 95 % purity. The binding assay demonstrated that the CNGRC-yCD fusion protein had specific binding affinity toward purified APN recombinant protein and high-APN-expressing cells, including human endothelial cells (HUVECs) and various types of human tumor cell lines, but not low-APN-expressing tumor cell lines. Moreover, the enzyme activity and cell viability assay showed that the CNGRC-yCD fusion protein could effectively convert 5-FC into 5-FU and resulted in significant cell death in both high-APN-expressing tumor cells and HUVECs.CONCLUSIONS:
This study successfully constructs a new targeting enzyme-prodrug system, CNGRC-yCD fusion protein/5-FC. Systematic experiments demonstrated that the CNGRC-yCD protein retained both the APN-binding affinity of NGR and the enzyme activity of yCD to convert 5-FC into 5-FU. The combined treatment of the CNGRC-yCD protein with 5-FC resulted in the significantly increased cell death of high-APN-expressing cells as compared to that of low-APN-expressing cells.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oligopeptídeos
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Saccharomyces cerevisiae
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Pró-Fármacos
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Sistemas de Liberação de Medicamentos
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Proteínas de Saccharomyces cerevisiae
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Citosina Desaminase
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Flucitosina
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Neoplasias
/
Antineoplásicos
Limite:
Humans
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article