Saracatinib Impairs Head and Neck Squamous Cell Carcinoma Invasion by Disrupting Invadopodia Function

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Elevated Src kinase activity is associated with solid tumor progression, particularly in head and neck squamous cell carcinoma (HNSCC).
• Src kinase plays a crucial role in regulating HNSCC proliferation and tumor invasion.
• Saracatinib, a small molecule inhibitor of Src, has shown potent anti-invasive effects in preclinical models, but its precise cellular mechanisms remain unclear.

Purpose of the Study:

• To investigate the anti-proliferative and anti-invasive effects of saracatinib on HNSCC.
• To elucidate the cellular mechanisms by which saracatinib perturbs HNSCC invasion.

Main Methods:

• Utilized preclinical cell line and mouse models of HNSCC.
• Assessed the impact of saracatinib on HNSCC cell growth, cell cycle, invasion, Src activation, and substrate phosphorylation.
• Evaluated saracatinib's effects on tumor growth, perineural invasion, lymph node metastasis, invadopodia formation, extracellular matrix degradation, and matrix metalloprotease 9 (MMP-9) activation in vivo.

Main Results:

• Saracatinib inhibited HNSCC cell growth, cell cycle progression, and Matrigel invasion in vitro.
• Dose-dependent decreases in Src activation and phosphorylation of invasion-associated substrates (FAK, p130 CAS, cortactin) were observed.
• In vivo, saracatinib impaired perineural invasion and cervical lymph node metastasis in an orthotopic tongue SCC mouse model, with no significant impact on primary tumor growth. It also inhibited invadopodia formation, ECM degradation, and MMP-9 activation.

Conclusions:

• Saracatinib effectively inhibits HNSCC pro-invasive activity by targeting Src kinase.
• Inhibition of Src substrate phosphorylation by saracatinib is critical for disrupting invadopodia formation and associated matrix metalloprotease activity, thereby reducing tumor cell invasion and metastasis.