HGF/c-Met acts as an alternative angiogenic pathway in sunitinib-resistant tumors

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Resistance to antiangiogenic therapy is a significant clinical challenge.
• Both tumor and stromal cells contribute to inherent and acquired resistance.
• Understanding resistance mechanisms is crucial for improving antiangiogenic treatment efficacy.

Purpose of the Study:

• To investigate the molecular mechanisms of resistance to sunitinib, a vascular endothelial growth factor receptor tyrosine kinase inhibitor.
• To identify potential therapeutic strategies to overcome sunitinib resistance.

Main Methods:

• Utilized experimental tumor models sensitive and resistant to sunitinib.
• Analyzed tumor protein lysates for growth factor concentrations (HGF).
• Quantified cell surface receptor expression (c-Met) using flow cytometry.
• Evaluated combination therapy efficacy (sunitinib + c-Met inhibitor) in vivo and in vitro.
• Assessed the impact of exogenous HGF on sunitinib sensitivity.

Main Results:

• Resistant tumors exhibited higher hepatocyte growth factor (HGF) concentrations compared to sensitive tumors.
• Endothelial cells showed significantly higher c-Met expression than tumor cells, indicating HGF targets vasculature.
• Combination therapy of sunitinib and a c-Met inhibitor effectively inhibited tumor growth in resistant models.
• Systemic HGF administration induced sunitinib resistance in sensitive models by maintaining tumor angiogenesis.

Conclusions:

• The HGF/c-Met pathway plays a critical role in the development of resistance to antiangiogenic therapy.
• Targeting the HGF/c-Met pathway in combination with sunitinib represents a promising strategy to circumvent resistance.
• This approach holds potential for clinical application in patients resistant to vascular endothelial growth factor receptor inhibitors.