Abstract: Objective: The goal of this study was to identify the potential curcumin binding proteins in oral cancer cells by biotin-streptavidin pull down technique. Methods: A curcumin-biotin conjugate was chemically synthesized and its activity was measured by MTT assay. Curcumin-binding proteins were eluted with streptavidin resin from curcumin-biotin treated oral cancer cells, separated by polyacrylamide gel electrophoresis, and identified by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Curcumin-binding properties of two of these proteins, Annexin A2 and CDKN2B, were studied further by streptavidin binding assay and western blotting with recombinant humum proteins. Results: Curcumin-biotin conjugate was successfully chemically synthesized and its activity was not affected by MTT assay. The potential curcumin binding proteins were eluted with streptavidin resin and separated by SDS-PAGE electrophoresis, and then analyzed by LC-MS/MS. 167 potential curcumin binding proteins were identifed with MASCOT. Binding assay with western blotting confirmed the binding of Annexin A2 and CDKN2B with curcumin in a dose-dependent manner. Conclusions: In summary, this study confirmed Annexin A2 and CDKN2B as new curcumin-binding proteins in oral squamous carcinoma cells.

Key words: Curcumin, Protein targets, Oral cancer