Targeted delivery of a designed sTRAIL mutant results in superior apoptotic activity towards EGFR-positive tumor cells

J Mol Med (Berl). 2008 Aug;86(8):909-24. doi: 10.1007/s00109-008-0348-9. Epub 2008 May 27.


Previously, we have shown that epidermal growth factor receptor (EGFR)-selective delivery of soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL), by genetic fusion to antibody fragment scFv425, enhances the tumor-selective pro-apoptotic activity of sTRAIL. Insight into the respective contribution of the agonistic receptors TRAIL-R1 and TRAIL-R2 to TRAIL-induced apoptosis may provide a rational approach to further optimize TRAIL-based therapy. Recently, this issue has been investigated using sTRAIL mutants designed to selectively bind to either receptor. However, the relative contribution of the respective TRAIL receptors, in particular TRAIL-R1, in TRAIL signaling is still unresolved. Here, we fused scFv425 to designed sTRAIL mutant sTRAILmR1-5, reported to selectively activate TRAIL-R1, and investigated the therapeutic apoptotic activity of this novel fusion protein. EGFR-specific binding of scFv425:sTRAILmR1-5 potently induced apoptosis, which was superior to the apoptotic activity of scFv425:sTRAIL-wt and a nontargeted MOCK-scFv:sTRAILmR1-5. During cotreatment with cisplatin or the histone deacetylase inhibitor valproic acid, scFv425:sTRAILmR1-5 retained its superior pro-apoptotic activity compared to scFv425:sTRAIL-wt. However, in catching-type Enzyme-Linked ImmunoSorbent Assays with TRAIL-R1:Fc and TRAIL-R2:Fc, scFv425:sTRAILmR1-5 was found to not only bind to TRAIL-R1 but also to TRAIL-R2. Binding to TRAIL-R2 also had functional consequences because the apoptotic activity of scFv425:sTRAILmR1-5 was strongly inhibited by a TRAIL-R2 blocking monoclonal antibody. Moreover, scFv425:sTRAILmR1-5 retained apoptotic activity upon selective knockdown of TRAIL-R1 using small inhibitory RNA. Collectively, these data indicate that both agonistic TRAIL receptors are functionally involved in TRAIL signaling by scFv425:sTRAILmR1-5 in solid tumor cells. Moreover, the superior target cell-restricted apoptotic activity of scFv425:sTRAILmR1-5 indicates its therapeutic potential for EGFR-positive solid tumors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / metabolism
  • Antineoplastic Agents / therapeutic use*
  • Apoptosis*
  • Binding Sites
  • Cell Line, Tumor
  • ErbB Receptors / antagonists & inhibitors
  • ErbB Receptors / metabolism*
  • Gene Transfer Techniques
  • Humans
  • Jurkat Cells
  • Ligands
  • Mutation
  • Neoplasms / metabolism
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / agonists
  • Receptors, TNF-Related Apoptosis-Inducing Ligand / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Fusion Proteins / therapeutic use
  • Signal Transduction
  • TNF-Related Apoptosis-Inducing Ligand / genetics*
  • TNF-Related Apoptosis-Inducing Ligand / metabolism
  • TNF-Related Apoptosis-Inducing Ligand / therapeutic use


  • Antibodies, Monoclonal
  • Antineoplastic Agents
  • Ligands
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Recombinant Fusion Proteins
  • TNF-Related Apoptosis-Inducing Ligand
  • ErbB Receptors