Tribody: robust self-assembled trimeric targeting ligands with high stability and significantly improved target-binding strength.
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.
Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina , Chapel Hill, North Carolina 27599-7568, United States.
Dongwook
D
Kim
Sang Kyun
SK
Kim
C Alexander
CA
Valencia
Rihe
R
Liu
D000818:Animals; D000954:Antigens, Surface / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001671:Biochemistry / Q000379:methods*; D002460:Cell Line; D066246:ErbB Receptors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005260:Female; D043425:Glutamate Carboxypeptidase II / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D064235:Matrilin Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D017434:Protein Structure, Tertiary
D000954:Antigens, Surface; D008024:Ligands; D064235:Matrilin Proteins; D066246:ErbB Receptors; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II