urcumin: A new radio-sensitizer of squamous cell arcinoma cells

o URPOSE: Curcumin, a potential chemopreventive gent, was found to inhibit cancer cells in S/G2M hases of the cell cycle, when radiation is more ffective. The purpose of the current study was to nvestigate whether curcumin can sensitize squaous cell carcinoma (SCC) cells to the ionizing ffects of irradiation. ETHODS: Curcumin (3.5 ) was added for 48 ours to an SCC cell line prior to irradiation. Cell rowth (counts) and colony-formation (colonoenic assay) were examined after radiation. ESULTS: Incubation with curcumin only (3.75 ) or 48 hours did not decrease the number of cells or he ability to form colonies in the absence of radition. However, in plates that were exposed to 1-5 y of radiation, cell counts dropped significantly if retreated with curcumin with a maximal effect at .5 Gy (where the cell counts dropped from 1240 to 017, P < 0.001). The colonogenic assay revealed a ignificant decrease in the ability to form colonies ollowing pretreatment with curcumin in all radiaion doses (P < 0.05). ONCLUSIONS: Given the appropriate doses, curumin exhibits radio-sensitizing effects on SCC cells n vitro. (Otolaryngol Head Neck Surg 2005;132: 17-21.)