MEK-dependent negative feedback underlies BCR-ABL-mediated oncogene addiction

Area of Science:

• Oncology
• Molecular Biology
• Cell Signaling

Background:

• The clinical efficacy of BCR-ABL tyrosine kinase inhibitors (TKI) in chronic myelogenous leukemia (CML) suggests oncogene addiction.
• The underlying molecular mechanisms of oncogene addiction remain incompletely understood.

Purpose of the Study:

• To elucidate the molecular basis of BCR-ABL-mediated oncogene addiction in CML.
• To investigate the role of growth factor receptor (GF-R) signaling pathways in this phenomenon.

Main Methods:

• Quantitative phosphoproteomic analysis of CML cells treated with BCR-ABL TKI.
• Development and validation of an isogenic model for BCR-ABL-mediated addiction.
• Assessment of GF-R signaling pathway dynamics and feedback mechanisms.

Main Results:

• Transient BCR-ABL TKI exposure led to persistent downregulation of GF-R signaling pathways.
• BCR-ABL rewires myeloid GF-R signaling, causing profound and sustained dampening of pathway activation.
• Restoration of ligand-mediated GF-R signaling was insufficient to prevent apoptosis.
• Prolonged MEK-dependent negative feedback was identified as a key mechanism facilitating BCR-ABL oncogene addiction.

Conclusions:

• BCR-ABL confers oncogene addiction by rewiring myeloid GF-R signaling via MEK-dependent negative feedback.
• Maintaining negative feedback alongside oncoprotein inhibition may enhance responses to targeted therapies in various cancers.