Novel agents that downregulate EGFR, HER2, and HER3 in parallel

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Epidermal Growth Factor Receptor (EGFR), Human Epidermal growth factor Receptor 2 (HER2), and Human Epidermal growth factor Receptor 3 (HER3) are key drivers in human cancer development and progression.
• Resistance to current therapies, including monoclonal antibodies and tyrosine kinase inhibitors, often stems from functional redundancy among EGFR, HER2, and HER3.
• These receptor tyrosine kinases share conserved extracellular structures stabilized by disulfide bonds, presenting a potential vulnerability.

Purpose of the Study:

• To identify novel compounds capable of simultaneously inactivating EGFR, HER2, and HER3 by disrupting their extracellular disulfide bonds.
• To evaluate the efficacy of these compounds in eliminating cancer cells, particularly those overexpressing EGFR or HER2.
• To explore the potential of these Disulfide Bond Disrupting Agents (DDAs) as a complementary therapeutic strategy to overcome resistance in cancer treatment.

Main Methods:

• Screening for compounds that induce cell death in breast cancer cell lines overexpressing EGFR or HER2.
• Assessing the effect of identified compounds on the expression levels of EGFR, HER2, and HER3.
• Characterizing the mechanism of action, specifically the disruption of extracellular disulfide bonds.
• Evaluating the in vivo anticancer efficacy and toxicity of lead compounds, such as DDA RBF3.

Main Results:

• Identification of Disulfide Bond Disrupting Agents (DDAs) that effectively kill breast cancer cells overexpressing EGFR or HER2.
• Observed parallel downregulation of EGFR, HER2, and HER3 expression correlating with cell death induced by DDAs.
• Demonstrated in vivo anticancer efficacy of DDA RBF3 at 40 mg/kg without observable toxicity.
• Confirmed that DDAs function by disrupting critical disulfide bonds within the extracellular domains of EGFR, HER2, and HER3.

Conclusions:

• Disulfide Bond Disrupting Agents (DDAs) represent a novel class of anticancer compounds targeting the EGFR family.
• DDAs effectively induce cancer cell death by disrupting essential disulfide bonds, leading to the downregulation of EGFR, HER2, and HER3.
• DDA RBF3 shows promising in vivo efficacy and safety, suggesting its potential as a therapeutic agent.
• DDAs may serve as valuable adjuncts to existing targeted therapies, potentially overcoming therapeutic resistance through combination regimens.