Suppression of migration, invasion, and metastasis of cisplatin-resistant head and neck squamous cell carcinoma through IKKβ inhibition.

We explored the role of the transcription factor, NF-κB, and its upstream kinase IKKβ in regulation of migration, invasion, and metastasis of cisplatin-resistant head and neck squamous cell carcinoma (HNSCC). We showed that cisplatin-resistant HNSCC cells have a stronger ability to migrate and invade, as well as display higher IKKβ/NF-κB activity compared to their parental partners. Importantly, we found that knockdown of IKKβ, but not NF-κB, dramatically impaired cell migration and invasion in these cells. Consistent with this, the IKKβ inhibitor, CmpdA, also inhibited cell migration and invasion. Previous studies have already shown that N-Cadherin, an epithelial-mesenchymal transition (EMT) marker, and IL-6, a pro-inflammatory cytokine, play important roles in regulation of HNSCC migration, invasion, and metastasis. We found that cisplatin-resistant HNSCC expressed higher levels of N-Cadherin and IL-6, which were significantly inhibited by CmpdA. More importantly, we showed that CmpdA treatment dramatically abated cisplatin-resistant HNSCC cell metastasis to lungs in a mouse model. Our data demonstrated the crucial role of IKKβ in control of migration, invasion, and metastasis, and implicated that targeting IKKβ may be a potential therapy for cisplatin-resistant metastatic HNSCC.