Targeting a cell state common to triple-negative breast cancers

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Triple-negative breast cancer (TNBC) lacks common therapeutic targets due to its heterogeneous mutational landscape.
• TNBC subtypes often share 'basal-like' transcriptional profiles, suggesting a potential strategy for targeted therapy.
• Exploiting cell state vulnerabilities offers a novel approach for treating aggressive cancers like TNBC.

Purpose of the Study:

• To identify novel therapeutic targets for triple-negative breast cancer (TNBC) by focusing on its transcriptional cell state.
• To investigate the efficacy and mechanism of action of compounds targeting TNBC cells.
• To explore spleen tyrosine kinase (SYK) as a potential therapeutic target in basal-like TNBC.

Main Methods:

• Conducted a large-scale chemical genetic screen to identify potential therapeutic compounds.
• Utilized a multi-omics approach and computational modeling to elucidate the mechanism of action.
• Performed quantitative phosphoproteomics to analyze signaling pathways affected by SYK inhibition.

Main Results:

• PKC412 (midostaurin) and related compounds induced apoptosis in basal-like TNBC cells and inhibited tumor growth in vivo.
• Spleen tyrosine kinase (SYK) was identified as a novel and unexpected therapeutic target in TNBC.
• SYK inhibition was shown to abrogate STAT3 signaling, explaining its selective efficacy in basal-like breast cancer cells.

Conclusions:

• Targeting spleen tyrosine kinase (SYK) represents a novel therapeutic strategy for a subset of triple-negative breast cancer patients.
• Exploiting cancer cell states, rather than solely relying on specific mutations, can lead to the discovery of new treatment approaches.
• This study highlights the potential of targeting non-oncogene addictions for effective cancer therapy.