Inactive ERBB receptors cooperate with reactive oxygen species to suppress cancer progression

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• The ERBB receptor family drives cancer growth and metastasis.
• Current therapies targeting single ERBB receptors are insufficient; simultaneous targeting is optimal.
• The juxtamembrane (jxm) domain of ERBB1, ERBB2, and ERBB3 is crucial for ERBB-dependent biology.

Purpose of the Study:

• To develop a novel therapeutic strategy targeting the conserved ERBB receptor jxm domain.
• To evaluate the efficacy of the decoy peptide EJ1 in inhibiting ERBB-driven cancer.
• To investigate the molecular mechanisms underlying EJ1's anticancer effects.

Main Methods:

• Synthesis of EJ1, a cell-penetrating peptide targeting the ERBB jxm domain.
• In vitro assays to assess EJ1's effects on ERBB receptor activation, cell death, and signaling pathways.
• Mitochondrial function assays to evaluate EJ1's impact on membrane potential and ROS production.
• In vivo studies using a mouse model of breast cancer to assess tumor growth and metastasis inhibition.

Main Results:

• EJ1 treatment induced cancer cell death and formed inactive ERBB multimers.
• EJ1 simultaneously reduced ERBB1, ERBB2, and ERBB3 activation.
• EJ1 activated myosin light chain-dependent cell blebbing and inactivated CaMKII signaling.
• EJ1 translocated to mitochondria, decreasing membrane potential and increasing ROS production.
• EJ1 inhibited tumor growth and metastasis in a mouse breast cancer model without toxicity.

Conclusions:

• Targeting the ERBB jxm domain with intracellular decoy peptides like EJ1 is a viable anticancer strategy.
• EJ1 demonstrates potent inhibition of tumor growth and metastasis by disrupting ERBB signaling.
• EJ1 represents a promising novel therapeutic for ERBB-driven cancers.