Cancer Therapy: Preclinical Curcumin Treatment Suppresses IKKb Kinase Activity of Salivary Cells of Patients with Head and Neck Cancer: A Pilot Study

Purpose: To determine whether curcumin would inhibit IkB kinase b (IKKb) 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 IKKb 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 IKKb 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 IKKb 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 fromHNSCC patients were also analyzed in a blinded fashion for expression of cytokines. IL-10, IFN-g , IL-12p70, and IL-2 clustered together, and granulocyte macrophage colony stimulating factor and TNF-a 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 IKKb kinase activity in the saliva of HNSCC patients, and this inhibition correlated with reduced expression of a number of cytokines. IKKb kinase could be a useful biomarker for detecting the effect of curcumin in head and neck cancer. Clin Cancer Res; 17(18); 5953–61. 2011 AACR.