Please use this identifier to cite or link to this item:
http://hdl.handle.net/10397/5261
| Title: | Pegylated derivatives of recombinant human arginase (rhArg1) for sustained in vivo activity in cancer therapy : preparation, characterization and analysis of their pharmacodynamics in vivo and in vitro and action upon hepatocellular carcinoma cell (HCC) | Authors: | Tsui, SM Lam, WM Lam, TL Chong, HC So, PK Kwok, SY Arnold, S Cheng, PNM Wheatley, DN Lo, WHT Leung, TYC |
Issue Date: | 17-Apr-2009 | Source: | Cancer cell international, 17 Apr. 2009, v. 9, no. 9, p. 1-13 | Abstract: | Background: Protein used in medicine, e.g. interferon, are immunogenic and quickly broken down by the body. Pegylation is a recognized way of preserving their integrity and reducing immune reactions, and works well with enzymes used to degrade amino acids, a recent focus of attention in controlling cancer growth. Of the two arginine-degrading enzymes being explored clinically, arginine deiminase is a decidedly foreign mycoplasm-derived enzyme, whereas human arginase 1 is a native liver enzyme. Both have been pegylated, the former with adjuncts of 20 kD, the latter with 5 kD PEG. Pegylation is done by several different methods, not all of which are satisfactory or desirable. Methods: The preparation of novel polyethylene glycol (PEG) derivatives for modifying proteins is described, but directed specifically at pegylation of recombinant human arginase 1 (rhArg1). rhArg1 expressed in Escherichia coli was purified and coupled in various ways with 5 different PEG molecules to compare their protective properties and the residual enzyme activity, using hepatocellular cell lines both in vitro and in vivo. Results: Methoxypolyethylene glycol-succinimidyl propionate (mPEG-SPA 5,000) coupled with very high affinity under mild conditions. The resulting pegylated enzyme (rhArg1-peg[sub 5,000 mw]) had up to 6 PEG chains of 5K length which not only protected it from degradation and any residual immunogenicity, but most importantly let it retain >90% of its native catalytic activity. It remained efficacious in depleting arginine in rats after a single ip injection of 1,500 U of the conjugate as the native enzyme, plasma arginine falling to >0.05 μM from ~170 μM within 20 min and lasting 6 days. The conjugate had almost the same efficacy as unpegylated rhArg1 on 2 cultured human liver cancer (HCC) cell lines. It was considerably more effective than 4 other pegylated conjugates prepared. Conclusion: Valuable data on the optimization of the pegylation procedure and choice of ligand that best stabilizes the enzyme arginase 1 are presented, a protocol that should equally fit many other enzymes and proteins. It is a long lasting arginine-depleting enzyme in vivo which will greatly improve its use in anti-cancer therapy. |
Publisher: | BioMed Central Ltd. | Journal: | Cancer cell international | ISSN: | 1475-2867 | DOI: | 10.1186/1475-2867-9-9 | Rights: | © 2009 Tsui et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Appears in Collections: | Journal/Magazine Article |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Tsui_Pegylated_derivatives_human.pdf | 715.36 kB | Adobe PDF | View/Open |
Access
View full-text via PolyU eLinks 
Page views
118
Last Week
1
1
Last month
Citations as of May 28, 2023
Downloads
138
Citations as of May 28, 2023
SCOPUSTM
Citations
56
Last Week
0
0
Last month
0
0
Citations as of Jun 1, 2023
WEB OF SCIENCETM
Citations
61
Last Week
0
0
Last month
0
0
Citations as of Jun 1, 2023
Google ScholarTM
Check
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.