[ Special series on Tumor angiogenesis ]
doi: 10.1186/s40880-016-0080-8
Comparisons of biophysical properties and bioactivities of mono-PEGylated endostatin and an endostatin analog
Shan Wang, Yan Fu and Yongzhang Luo
The National Engineering Laboratory for Anti-tumor Protein Therapeutics, School of Life Sciences, Tsinghua University
[Abstract]
Background
Endostatin (ES) is a well-established potent endogenous antiangiogenic factor. An ES variant, called zinc-binding protein-ES (ZBP-ES), is clinically available; however, its use is limited by rapid renal clearance and short residence time. PEGylation has been exploited to overcome these shortcomings, and mono-PEGylated ES (called M2ES) as well as mono-PEGylated ZBP-ES (MZBP-ES) are developed in our study. This study aimed to compare the biophysical properties and biological effects of M2ES and MZBP-ES to evaluate their druggability.
Methods
Circular dichroism and tryptophan emission fluorescence were used to monitor the conformational changes of M2ES and MZBP-ES. Their resistance to trypsin digestion and guanidinium chloride (GdmCl)-induced unfolding was examined by Coomassie staining and tryptophan emission fluorescence, respectively. The biological effects of M2ES and MZBP-ES on endothelial cell migration were evaluated using Transwell migration and wound healing assays, and the uptake of M2ES and MZBP-ES in endothelial cells was also compared by Western blotting and immunofluorescence.
Results
Structural analyses revealed that M2ES has a more compact tertiary structure than MZBP-ES. Moreover, M2ES was more resistant to trypsin digestion and GdmCl-induced unfolding compared with MZBP-ES. In addition, although M2ES and MZBP-ES showed comparable levels of inhibiting transwell migration and wound healing of endothelial cells, M2ES displayed an increased ability to enter cells compared with MZBP-ES, possibly caused by the enhanced interaction with nucleolin.
Conclusions
M2ES has a more compact tertiary structure, is more stable for trypsin digestion and GdmCl-induced unfolding, exhibits increased cellular uptake and shows equivalent inhibitory effects on cell migration relative to MZBP-ES, indicating that M2ES is a more promising candidate for anticancer drug development compared with MZBP-ES.
Background
Endostatin (ES) is a well-established potent endogenous antiangiogenic factor. An ES variant, called zinc-binding protein-ES (ZBP-ES), is clinically available; however, its use is limited by rapid renal clearance and short residence time. PEGylation has been exploited to overcome these shortcomings, and mono-PEGylated ES (called M2ES) as well as mono-PEGylated ZBP-ES (MZBP-ES) are developed in our study. This study aimed to compare the biophysical properties and biological effects of M2ES and MZBP-ES to evaluate their druggability.
Methods
Circular dichroism and tryptophan emission fluorescence were used to monitor the conformational changes of M2ES and MZBP-ES. Their resistance to trypsin digestion and guanidinium chloride (GdmCl)-induced unfolding was examined by Coomassie staining and tryptophan emission fluorescence, respectively. The biological effects of M2ES and MZBP-ES on endothelial cell migration were evaluated using Transwell migration and wound healing assays, and the uptake of M2ES and MZBP-ES in endothelial cells was also compared by Western blotting and immunofluorescence.
Results
Structural analyses revealed that M2ES has a more compact tertiary structure than MZBP-ES. Moreover, M2ES was more resistant to trypsin digestion and GdmCl-induced unfolding compared with MZBP-ES. In addition, although M2ES and MZBP-ES showed comparable levels of inhibiting transwell migration and wound healing of endothelial cells, M2ES displayed an increased ability to enter cells compared with MZBP-ES, possibly caused by the enhanced interaction with nucleolin.
Conclusions
M2ES has a more compact tertiary structure, is more stable for trypsin digestion and GdmCl-induced unfolding, exhibits increased cellular uptake and shows equivalent inhibitory effects on cell migration relative to MZBP-ES, indicating that M2ES is a more promising candidate for anticancer drug development compared with MZBP-ES.
Chinese Journal of Cancer 2016, Volume: 35, Issue 2
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Shan Wang, Yan Fu and Yongzhang Luo. Comparisons of biophysical properties and bioactivities of mono-PEGylated endostatin and an endostatin analog. Chin J Cancer. 2016, 35:14. doi:10.1186/s40880-016-0080-8
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[ Html full-text / Citation export] (BioMed Central)
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[ More articles of the special series on Tumor angiogenesis ]
Cite this article
Shan Wang, Yan Fu and Yongzhang Luo. Comparisons of biophysical properties and bioactivities of mono-PEGylated endostatin and an endostatin analog. Chin J Cancer. 2016, 35:14. doi:10.1186/s40880-016-0080-8
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