Tribody: robust self-assembled trimeric targeting ligands with high stability and significantly improved target-binding strength

Biochemistry. 2013 Oct 15;52(41):7283-94. doi: 10.1021/bi400716w. Epub 2013 Oct 3.

Abstract

The C-terminal coiled-coil region of mouse and human cartilage matrix protein (CMP) self-assembles into a parallel trimeric complex. Here, we report a general strategy for the development of highly stable trimeric targeting ligands (tribodies), against epidermal growth factor receptor (EGFR) and prostate-specific membrane antigen (PSMA) as examples, by fusing a specific target-binding moiety with a trimerization domain derived from CMP. The resulting fusion proteins can efficiently self-assemble into a well-defined parallel homotrimer with high stability. Surface plasmon resonance (SPR) analysis of the trimeric targeting ligands demonstrated significantly enhanced target-binding strength compared with the corresponding monomers. Cellular-binding studies confirmed that the trimeric targeting ligands have superior binding strength toward their respective receptors. Significantly, the EGFR-binding tribody was considerably accumulated in the tumor of mice bearing xenografted EGFR-positive tumors, indicating its effective cancer-targeting feature under in vivo conditions. Our results demonstrate that CMP-based self-assembly of tribodies can be a general strategy for the facile and robust generation of trivalent targeting ligands for a wide variety of in vitro and in vivo applications.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antigens, Surface / chemistry*
  • Antigens, Surface / genetics
  • Antigens, Surface / metabolism*
  • Biochemistry / methods*
  • Cell Line
  • ErbB Receptors / chemistry*
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Female
  • Glutamate Carboxypeptidase II / chemistry*
  • Glutamate Carboxypeptidase II / genetics
  • Glutamate Carboxypeptidase II / metabolism*
  • Humans
  • Ligands
  • Matrilin Proteins / chemistry*
  • Matrilin Proteins / genetics
  • Matrilin Proteins / metabolism
  • Mice
  • Mice, Nude
  • Protein Binding
  • Protein Multimerization
  • Protein Stability
  • Protein Structure, Tertiary

Substances

  • Antigens, Surface
  • Ligands
  • Matrilin Proteins
  • ErbB Receptors
  • FOLH1 protein, human
  • Glutamate Carboxypeptidase II