Global Protease Activity Profiling Identifies HER2-Driven Proteolysis in Breast Cancer

Area of Science:

• Biochemistry
• Molecular Biology
• Oncology

Background:

• Differential expression of extracellular proteases and inhibitors is linked to breast cancer subtypes.
• Protease activity, not just expression, is crucial for understanding malignant transformation due to post-translational regulation.

Purpose of the Study:

• To investigate global extracellular protease activity profiles in breast cancer subtypes.
• To identify subtype-specific proteases involved in cancer signaling and functional roles.
• To explore proteolysis in HER2-subtype breast cancer and its association with TGF-β signaling.

Main Methods:

• Utilized a global peptide library-based approach to profile protease activities across breast cancer cell lines.
• Employed transcriptional profiling and cell line clustering based on protease cleavage data.
• Developed an isogenic cell line model for detailed analysis of proteolysis in the HER2 subtype.

Main Results:

• Identified distinct proteolytic signatures differentiating breast cancer cell lines, expanding on transcriptional classification.
• Revealed a proteolytic signature in the HER2 subtype consistent with activated TGF-β signaling.
• Found BMP1 (a metalloprotease in TGF-β signaling) upregulated in protein and activity levels.
• Inhibition of BMP1 and HER2 reduced invasion in HER2-expressing cells by 35%.

Conclusions:

• Global extracellular proteolysis profiling reveals subtype-specific differences in breast cancer.
• Proteolysis is associated with HER2-mediated signaling, with BMP1 playing a significant role.
• Targeting BMP1 in conjunction with HER2 inhibition presents a potential therapeutic strategy for HER2-positive breast cancer.