Naturally occurring diarylheptanoid curcumin (CUR), a principal component of the Asian spice turmeric, has been shown to have anti-cancer effects in many tumor types. However, a detailed mechanism regarding CUR induced tumor cell killing remain to be comprehensively explored. Using two head neck squamous cell carcinoma (HNSCC) cell lines FaDu (hypopharyngeal) and Cal27 (tongue), we demonstrated a novel mechanism by which CUR levies the cytotoxic effect. We found that CUR induced upregulation of pro-apoptotic Bik, down-regulation of survival signaling by AKT and NF-κB prior to the induction of the caspase-cascade reduction of cell proliferation, are primary mechanisms of CUR-induced cell death, thus providing insights into the anti-tumor activity of CUR in HNSCC cells.
Keywords: Bik; Curcumin; apoptosis; caspase-3; caspase-9; head and neck cancer; natural product; squamous cell carcinoma.