Preparation and evaluation of a new releasable PEGylated tumor necrosis factor-α (TNF-α) conjugate for therapeutic application

Sci China Life Sci. 2013 Jan;56(1):51-8. doi: 10.1007/s11427-012-4431-7. Epub 2013 Jan 12.


To design a releasable PEGylated TNF-α (rPEG-TNF-α), a cathepsin B-sensitive dipeptide (Val-Cit moiety) was inserted into conventional PEG-modified TNF-α (PEG-TNF-α), facilitating its clinical use for anti-tumor therapy. Comparative pharmacokinetic and pharmacodynamic studies showed that the half-lives of both PEGylated forms of TNF-α were ∼60-fold greater than that of unmodified TNF-α. In addition, the in vitro bioactivity of rPEG-TNF-α was greater than that of PEG-TNF-α with the same degree of PEG modification. Release of TNF-α from rPEG-TNF-α in vitro was dependent on the presence of cathepsin B and was inhibited by a cathepsin B inhibitor. Despite the potent cytotoxicity of unmodified TNF-α against normal cells, its PEGylated forms at higher TNF-α concentrations showed low cytotoxic activity against these cells. In contrast, both forms of PEGylated TNF-α showed potent cytotoxic activity against the B16 and L929 cell lines, with rPEG-TNF-α being 5- and 9-fold more potent, respectively, than PEG-TNF-α. Moreover, rPEG-TNF-α was a more potent in vivo antitumor agent than PEG-TNF-α.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Cathepsin B / antagonists & inhibitors
  • Cathepsin B / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Dipeptides / chemistry*
  • Dose-Response Relationship, Drug
  • Drug Compounding
  • Drug Evaluation, Preclinical
  • Glycopeptides / pharmacology
  • Humans
  • Hydrogen-Ion Concentration
  • Leucine / analogs & derivatives
  • Leucine / pharmacology
  • Lysosomes / enzymology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neoplasms, Experimental / drug therapy*
  • Neoplasms, Experimental / metabolism
  • Neoplasms, Experimental / pathology
  • Pepstatins / pharmacology
  • Polyethylene Glycols / chemistry*
  • Protease Inhibitors / pharmacology
  • Rats
  • Time Factors
  • Tumor Burden / drug effects
  • Tumor Necrosis Factor-alpha / chemistry
  • Tumor Necrosis Factor-alpha / pharmacokinetics
  • Tumor Necrosis Factor-alpha / pharmacology*


  • Antineoplastic Agents
  • Dipeptides
  • Glycopeptides
  • Pepstatins
  • Protease Inhibitors
  • Tumor Necrosis Factor-alpha
  • Polyethylene Glycols
  • Cathepsin B
  • Leucine
  • ubenimex
  • phosphoramidon
  • pepstatin