Curcumin: A potential radio-enhancer in head and neck cancer

Objectives/Hypothesis: To investigate whether curcumin enhances the cytotoxic effect of radiotherapy in head and neck squamous cell carcinoma (HNSCC). Methods: HNSCC cell lines SCC‐1, SCC‐9, KB, as well as A431 cell line were treated with curcumin, irradiation, or their combination. Cell viability was evaluated by XTT assay. Cyclooxygenase‐2 (COX‐2), epithelial growth factor receptor (EGFR), and p‐Erk1/2 were measured by Western blot analysis. CD‐1 athymic nude mice with orthotopic implanted SCC‐1 cells, were treated with control diet, curcumin containing diet, local single‐dose radiation, or combination. Results: Curcumin (IC50 range, 15–22 μM) and radiation inhibited cell viability in all cell lines were tested. The combination of curcumin and radiation resulted in additive effect. Curcumin decreased COX‐2 expression and inhibited phosphorylation of EGFR in SCC‐1 cells. In tumor‐bearing mice the combination regimen showed a decrease in both tumor weight (25%, P = .09) and tumor size (15%, P = .23) compared to the nontreated mice. Conclusions: Curcumin inhibited HNSCC cell growth and augmented the effect of radiation in vitro and in vivo. A possible mechanism is inhibition of COX‐2 expression and EGFR phosphorylation. Laryngoscope, 2009