Open AccessComparisons of biophysical properties and bioactivities of mono‐PEGylated endostatin and an endostatin analog
Author(s) -
Wang Shan,
Fu Yan,
Luo Yongzhang
Publication year - 2016
Publication title -
cancer communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.119
H-Index - 53
ISSN - 2523-3548
DOI - 10.1186/s40880-016-0080-8
Subject(s) - chemistry , trypsin , endostatin , protein tertiary structure , circular dichroism , biophysics , biochemistry , angiogenesis , guanidinium chloride , microbiology and biotechnology , cancer research , biology , enzyme
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 M 2 ES) 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 M 2 ES and MZBP‐ES to evaluate their druggability. Methods Circular dichroism and tryptophan emission fluorescence were used to monitor the conformational changes of M 2 ES 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 M 2 ES and MZBP‐ES on endothelial cell migration were evaluated using Transwell migration and wound healing assays, and the uptake of M 2 ES and MZBP‐ES in endothelial cells was also compared by Western blotting and immunofluorescence. Results Structural analyses revealed that M 2 ES has a more compact tertiary structure than MZBP‐ES. Moreover, M 2 ES was more resistant to trypsin digestion and GdmCl‐induced unfolding compared with MZBP‐ES. In addition, although M 2 ES and MZBP‐ES showed comparable levels of inhibiting transwell migration and wound healing of endothelial cells, M 2 ES displayed an increased ability to enter cells compared with MZBP‐ES, possibly caused by the enhanced interaction with nucleolin. Conclusions M 2 ES 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 M 2 ES is a more promising candidate for anticancer drug development compared with MZBP‐ES.