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Updated: Sep 25, 2025
Polymalic Acid-based Nano Biopolymers for Targeting of Multiple Tumor Markers: An Opportunity for Personalized Medicine?
Published on: June 13, 2014
Strategic design to create HER2-targeting proteins with target-binding peptides immobilized on a fibronectin type III
Wanaporn Yimchuen1, Tetsuya Kadonosono1, Yumi Ota1
1School of Life Science and Technology, Tokyo Institute of Technology Yokohama 226-8501 Japan tetsuyak@bio.titech.ac.jp +81-45-924-5848 +81-45-924-5848.
Abstract:
Tumor-binding peptides such as human epidermal growth factor receptor 2 (HER2)-binding peptides are attractive therapeutic and diagnostic options for cancer. However, the HER2-binding peptides (HBPs) developed thus far are susceptible to proteolysis and lose their affinity to HER2 in vivo. In this report, a method to create a HER2-binding fluctuation-regulated affinity protein (HBP-FLAP) consisting of a fibronectin type III domain (FN3) scaffold with a structurally immobilized HBP is presented. HBPs were selected by phage-library screening and grafted onto FN3 to create FN3-HBPs, and the HBP-FLAP with the highest affinity (HBP sequence: YCAHNM) was identified after affinity maturation of the grafted HBP. HBP-FLAP containing the YCAHNM peptide showed increased proteolysis-resistance, binding to HER2 with a dissociation constant (K D) of 58 nM in ELISA and 287 nM in biolayer interferometry and specifically detects HER2-expressing cancer cells. In addition, HBP-FLAP clearly delineated HER2-expressing tumors with a half-life of 6 h after intravenous injection into tumor-bearing mice. FN3-based FLAP is an excellent platform for developing target-binding small proteins for clinical applications.
Insights
Researchers developed a HER2-binding fluctuation-regulated affinity protein (HBP-FLAP) to overcome limitations of current HER2-binding peptides. This novel protein exhibits enhanced stability and specific tumor targeting for cancer diagnostics and therapeutics.
Area of Science:
- Biotechnology
- Molecular Biology
- Oncology
Background:
- Tumor-binding peptides, like those targeting human epidermal growth factor receptor 2 (HER2), offer potential for cancer therapy and diagnostics.
- Existing HER2-binding peptides (HBPs) face challenges with proteolysis and reduced *in vivo* affinity.
Purpose of the Study:
- To develop a novel HER2-binding protein with improved stability and affinity for clinical applications.
- To engineer a HER2-binding fluctuation-regulated affinity protein (HBP-FLAP) using a fibronectin type III (FN3) domain scaffold.
Main Methods:
- Selected HBPs via phage-library screening and grafted them onto an FN3 scaffold.
- Performed affinity maturation to identify the highest-affinity HBP-FLAP (YCAHNM peptide).
- Evaluated HBP-FLAP's proteolysis resistance, HER2 binding affinity (ELISA, biolayer interferometry), and *in vivo* tumor detection in mice.
Main Results:
- Identified HBP-FLAP with YCAHNM peptide demonstrating increased proteolysis resistance.
- Achieved HER2 binding with dissociation constants of 58 nM (ELISA) and 287 nM (biolayer interferometry).
- Demonstrated specific detection of HER2-expressing cancer cells and clear delineation of HER2-positive tumors *in vivo* with a 6-hour half-life.
Conclusions:
- The FN3-based HBP-FLAP platform offers enhanced stability and specific HER2 targeting.
- HBP-FLAP represents a promising tool for developing targeted cancer therapeutics and diagnostics.
- This engineered protein has significant potential for clinical translation in oncology.
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