Development of parallel reaction monitoring (PRM)-based quantitative proteomics applied to HER2-Positive breast...

Area of Science:

• Biomarker discovery in oncology
• Proteomics and mass spectrometry applications
• Translational research in breast cancer

Background:

• HER2-targeted therapies have advanced HER2-positive breast cancer treatment.
• Biomarkers beyond HER2 expression are needed to guide HER2-targeted therapies.
• The Human Epidermal Growth Factor Receptor 2 (HER2/ERBB2) pathway is crucial in breast cancer.

Purpose of the Study:

• To develop and validate a Parallel Reaction Monitoring (PRM) assay for quantifying key proteins in the HER2 pathway.
• To evaluate the utility of PRM in predicting sensitivity to anti-HER2 therapies.
• To assess PRM's correlation with existing methods like western blot and immunohistochemistry.

Main Methods:

• Parallel Reaction Monitoring (PRM) assay development and validation for sensitivity, linearity, and reproducibility.
• Application of PRM to breast cancer cell lines (BCLs), including those treated with anti-HER2 agents.
• Analysis of patient-derived xenografts (PDXs) and clinical breast cancer samples using PRM.

Main Results:

• PRM measurements in BCLs correlated well with western blot, immunocytochemistry, and transcriptomic data.
• Baseline HER2, EGFR, PTEN, and HER3 expression, along with low phospho-HER2, predicted trastuzumab sensitivity.
• PRM detected dynamic changes in HER2 and phospho-HER2 levels under trastuzumab and lapatinib, correlating with drug sensitivity.

Conclusions:

• A PRM-based assay effectively quantifies HER2 pathway proteins in breast cancer samples.
• The magnitude of protein expression measured by PRM may be relevant for predicting treatment sensitivity.
• PRM offers a promising approach for biomarker development in HER2-positive breast cancer.