ABSTRACT
PURPOSE: To determine whether curcumin would inhibit IκB kinase ß (IKKß) kinase activity and suppress expression of proinflammatory cytokines in head and neck squamous cell carcinoma cancer (HNSCC) patients. EXPERIMENTAL DESIGN: Saliva was collected before and after subjects chewed curcumin tablets. Protein was extracted and IKKß kinase activity measured. Interleukin (IL)-6 and IL-8 levels in the salivary supernatants were measured by ELISA. IL-6, IL-8, and other interleukin were also measured independently with ELISA to confirm the inhibitory effect of curcumin on expression and secretion of salivary cytokines. RESULTS: Curcumin treatment led to a reduction in IKKß kinase activity in the salivary cells of HNSCC patients (P < 0.05). Treatment of UM-SCC1 cells with curcumin as well as with post-curcumin salivary supernatant showed a reduction of IKKß kinase activity. Significant reduction of IL-8 levels (P < 0.05) was seen in post-curcumin samples from patients with dental caries. Although there was reduced IL-8 expression in 8 of 21 post-curcumin samples of HNSCC patients, the data did not reach statistical significance. Saliva samples from HNSCC patients were also analyzed in a blinded fashion for expression of cytokines. IL-10, IFN-γ, IL-12p70, and IL-2 clustered together, and granulocyte macrophage colony stimulating factor and TNF-α clustered together. Log10 ratio analysis showed decrease in expression of all nine cytokines in both the salivary supernatant and salivary cells of curcumin-treated samples. CONCLUSIONS: Curcumin inhibited IKKß kinase activity in the saliva of HNSCC patients, and this inhibition correlated with reduced expression of a number of cytokines. IKKß kinase could be a useful biomarker for detecting the effect of curcumin in head and neck cancer.
