Insights into HER2 signaling from step-by-step optimization of anti-HER2 antibodies

Area of Science:

• Oncology
• Immunology
• Structural Biology

Background:

• HER2 overexpression is common in breast cancer, driving tumor growth.
• Trastuzumab is an effective anti-HER2 therapy, but resistance limits its use.
• Targeting HER2/HER3 signaling offers a complementary approach to overcome resistance.

Purpose of the Study:

• To develop and characterize a novel anti-HER2 antibody, hHERmAb-F0178C1.
• To evaluate its efficacy in blocking HER2/HER3 signaling and potential for combination therapy.
• To understand the structural basis of its interaction with HER2.

Main Methods:

• Phage display library screening to isolate anti-HER2 antibody.
• Antibody optimization and crystallographic analysis (3.5 Å resolution).
• Assessment of HER2/HER3 heterodimerization and signaling inhibition, including combination with pertuzumab.

Main Results:

• hHERmAb-F0178C1 targets domain III of HER2.
• The antibody effectively inhibits HER2/HER3 heterodimerization and downstream signaling.
• Combination therapy with pertuzumab demonstrated synergistic anti-cancer effects.
• Structural analysis revealed the importance of a ligand-binding site in HER2 domain III.

Conclusions:

• hHERmAb-F0178C1 is a novel anti-HER2 antibody with potent HER2/HER3 signaling inhibition.
• Its complementary mechanism and synergistic effects with pertuzumab suggest significant clinical potential for breast cancer treatment.
• This antibody warrants further investigation as a promising therapeutic option, particularly for trastuzumab-resistant cases.