A System-wide Approach to Monitor Responses to Synergistic BRAF and EGFR Inhibition in Colorectal Cancer Cells

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• Targeted cancer therapy, particularly for colorectal cancer with BRAF(V600E) mutations, faces significant challenges due to intrinsic and acquired resistance.
• Combination treatments, such as dual inhibition of BRAF(V600E) and EGFR, have shown promise in increasing antitumor activity but may not be the sole effective strategy against BRAF inhibitor resistance.

Purpose of the Study:

• To investigate the molecular responses to single and multi-target treatments over time in BRAF(V600E) mutant colorectal cancer cells.
• To identify known and novel resistance mechanisms to BRAF inhibitors.

Main Methods:

• Utilized BRAF(V600E) mutant colorectal cancer cells as a model system.
• Integrated transcriptomic, proteomic, and phosphoproteomic data for a comprehensive molecular overview.
• Analyzed cellular responses to single and multi-target treatments over time.

Main Results:

• Observed widespread up-regulation of receptor tyrosine kinases (RTKs) upon BRAF inhibition.
• Identified up-regulation of metabolic pathways as a key response to BRAF inhibition.
• Revealed cellular adaptation mechanisms including switching energy sources and entering a quiescent-like state.

Conclusions:

• BRAF inhibition in colorectal cancer triggers compensatory mechanisms involving RTK and metabolic pathway activation.
• These adaptive responses, including metabolic switching and quiescence, contribute to intrinsic resistance to BRAF inhibitors.
• Understanding these novel resistance pathways is crucial for developing more effective targeted therapies for BRAF-mutant colorectal cancer.