Novel Humanized Anti-HER3 Antibodies: Structural Characterization and Therapeutic Activity

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• The ErbB protein family, including HER3, is crucial in solid tumor progression.
• HER3 activation promotes tumor growth and survival, contributing to therapy resistance.
• HER3's role in heterodimerization with other ErbB receptors drives oncogenic signaling.

Purpose of the Study:

• To generate and characterize humanized monoclonal antibodies targeting HER3.
• To evaluate the therapeutic potential of these antibodies in inhibiting HER3 function.
• To assess the antibodies' efficacy against HER3-driven cancers.

Main Methods:

• Humanization of murine monoclonal antibodies TK-A3 and TK-A4.
• Assessment of antibody binding to HER3 and competition with neuregulin-1β (NRG).
• Analysis of downstream signaling pathways (p-ErbB3, Akt, MAPK) and in vitro/in vivo antitumor activity.

Main Results:

• TK-hu A3 and TK-hu A4 demonstrated specific binding to HER3 without cross-reactivity.
• Antibodies competed with NRG, inhibiting key signaling pathways in a dose-dependent manner.
• TK-hu A3 showed significant in vitro and in vivo antitumor efficacy with good tolerability.

Conclusions:

• TK-hu A3 is a promising lead candidate for HER3-targeted therapy.
• The antibody exhibits specific HER3 targeting, potent pathway inhibition, and antitumor activity.
• TK-hu A3 holds potential for combination therapies and treating resistant HER3-positive cancers.