Systematic mapping of BCL-2 gene dependencies in cancer reveals molecular determinants of BH3 mimetic sensitivity

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• BCL-2 family proteins are crucial regulators of apoptosis.
• BH3 mimetics targeting BCL-2 family proteins show anti-cancer potential.
• Cancer cell dependencies on BCL-2 family members are not fully understood.

Purpose of the Study:

• To define cancer cell sensitivity to combinations of BCL-2, BCL-XL, and MCL-1 inhibitors.
• To identify biomarkers predicting sensitivity and resistance to these inhibitors.
• To discover novel targets for overcoming resistance to BH3 mimetics.

Main Methods:

• Drug screening of cancer cell lines from ten tissue types against selective BCL-2, BCL-XL, and MCL-1 inhibitors.
• Analysis of gene expression and EMT status as predictors of drug sensitivity.
• CRISPR/Cas9 screening to identify resistance mechanisms.

Main Results:

• Most tested cancer cell lines demonstrated dependence on at least one combination of BCL-2, BCL-XL, or MCL-1 inhibitors.
• BCL-2 gene expression predicted sensitivity to single BH3 mimetics.
• Epithelial-mesenchymal transition (EMT) status predicted synergistic dependence on BCL-XL and MCL-1 inhibition.
• BFL-1 and BCL-w were identified as mediators of resistance to tested BH3 mimetic combinations.

Conclusions:

• This study provides a framework for rationally targeting BCL-2 family dependencies in various cancers.
• Development of selective BFL-1 and BCL-w inhibitors is motivated to overcome intrinsic resistance to BH3 mimetics.
• Understanding BCL-2 family co-dependencies is key for effective cancer therapy.