Lysine-deficient lymphotoxin-alpha mutant for site-specific PEGylation

作者：Narimatsu Shogo; Yoshioka Yasuo^*; Watanabe Hikaru; Masano Takashi; Morishige Tomohiro; Yao Xinglei; Tanabe Aya; Tsunoda Shin ichi; Tsutsumi Yasuo; Mukai Yohei; Okada Naoki; Nakagawa Shinsaku

来源：Cytokine, 2011, 56(2): 489-493.

DOI：10.1016/j.cyto.2011.08.021

• Bioconjugation
• Cancer immunotherapy
• Cytokine
• Bioactivity
• Protein engineering

The cytokine lymphotoxin-alpha (LT alpha) is a promising anticancer agent; however, its instability currently limits its therapeutic potential. Modification of proteins with polyethylene glycol (PEGylation) can improve their in vivo stability, but PEGylation occurs randomly at lysine residues and the N-terminus. Therefore, PEGylated proteins are generally heterogeneous and have lower bioactivity than their non-PEGylated counterparts. Previously, we created phage libraries expressing mutant LT alpha s in which the lysine residues of wild-type LT alpha (wtLT alpha) were substituted for other amino acids. Here, we attempted to create a lysine-deficient mutant LT alpha with about the same bioactivity as wtLT alpha by using these libraries and site-specific PEGylation of the N-terminus. We isolated a lysine-deficient mutant LT alpha, LT-KO, with almost identical bioactivity to that of wtLT alpha against mouse LM cells. The bioactivity of wtLT alpha decreased to 10% following random PEGylation, whereas that of LT-K0 decreased to 50% following site-specific PEGylation; PEGylated LT-K0 retained five times the bioactivity of randomly PEGylated wtLT alpha. These results suggest that site-specific PEGylated LT-KO may be useful in cancer therapy.

• 出版日期2011-11
• 单位浙江大学