5′-Nitro-indirubinoxime, an indirubin derivative, suppresses metastatic ability of human head and neck cancer cells through the inhibition of Integrin β1/FAK/Akt signaling

Head and neck cancer is a malignant cancer and has the high infiltrative potential leading to metastasis. The objective of the study was to investigate the effects of 5′-nitro-indirubinoxime (5′-NIO), an indirubin derivative, on metastasis of head and neck cancer cells and to explore the underlying molecular mechanisms involved in this process. After treatment of head and neck cancer cells with 5′-NIO, cell metastatic behaviors such as colony formation, invasion, and migration were inhibited in a concentration-dependent manner. 5′-NIO inhibited the beta1 Integrin/FAK/Akt pathway which can then facilitate invasion and/or migration of cancer cells through the extracellular matrix (ECM). Moreover, treatment of head and neck cancer cell with Integrin β1 siRNA or FAK inhibitor effectively inhibited the invasion and migration, suggesting their regulatory role at invasiveness and migratory of head and neck cancer cells. In vivo CAM assay, treatment with 5′-NIO reduced the angiogenesis in FaDu cells xenograft fertilized chicken eggs, primarily by inhibiting expression of VEGF. We conclude that 5′-NIO inhibits the metastatic ability of head and neck cancer cells by blocking the Integrin β1/FAK/Akt pathway.