Investigating a Novel Interaction of c-MET and BACH1 in Head and Neck Squamous Cell Carcinoma Metastasis

Metastasis is estimated to be responsible for 90% of cancer deaths, and fewer than 10% of patients with metastatic head and neck squamous cell carcinoma (HNSCC) survive beyond 5 years. HNSCC is responsible for upwards of 270,000 global deaths annually, with up to 30% more cases projected annually by 2030. The proto-oncogene MET encodes for the tyrosine kinase receptor c-MET, which is overexpressed in over 80% of human papilloma virus (HPV)-negative HNSCC cases and particularly enriched in metastatic lymph nodes. c-MET is activated by its ligand, hepatocellular growth factor (HGF), and is known to promote cancer cell migration, proliferation, and metastasis through a variety of downstream effectors. Thus far, unfortunately, inhibition of c-MET has shown low efficacy as a single-agent therapy in clinical trials, which indicates a need for further understanding of the mechanisms underlying c-MET-mediated metastasis in HNSCC. We show here that human HNSCC cells upregulate expression of the transcription factor BACH1 through c-MET activation upon HGF treatment. In accordance with previous reports, HGF activation increased expression of epithelial-mesenchymal transition (EMT) markers. Similarly, BACH1 suppression reduced expression of these EMT markers. By pharmacological inhibition of c-MET by FDA-approved capmatinib in combination with hemin treatment to reduce BACH1 expression, migration was reduced compared to either treatment alone in scratch-wound migration assays. Collectively, these data indicate that BACH1 and c-MET are both necessary for the regulation of EMT and migration in HNSCC. Our data suggest the potential for combination therapy targeting both c-MET and BACH1 to reduce HNSCC metastasis.