T83 inhibited viability of NPC cells. Chemical structures of T83 (A). NPC cells were incubated with various concentrations of curcumin (B) or T83 (C) for 48 h or exposed to 0.5 μM T83 (D) for 24, 48, and 72 h; cell viability was then quantified by the MTT assay. (E) Clonogenic survival of NPC cells treated with curcumin. (F) Representative results of colony formation assays with CNE2 and CNE2R cells. (G) Quantification of colonies. All data represent three independent experiments, mean ± s.d. *
P < 0.05, **
P < 0.01.