The anti-tumor effects of 11-Epi-sinulariolide, an active ingredient isolated from soft coral Sinularia leptoclados, on CAL-27 cells were investigated in this study. In the MTT assay for cell proliferation, the inhibition ratio increased as the concentration of 11-Epi-sinulariolide increased. When a concentration of 1.5g /ml of 11-Epi-sinulariolide was applied, the CAL-27 cells viability was reduced to a level of 70% of the control sample. The wound healing function decreased as the concentration of 11-Epi-sinulariolide increased. The results in this study indicated that treatment with 11-Epi-sinulariolide for 6h significantly induced both early and late apoptosis of CAL-27 cells, observed by flow cytometric measurement and microscopic fluorescent observation. A comparative proteomic analysis was conducted to investigate the effects of 11-Epi-sinulariolide on CAL-27 cells at the molecular level by comparison between the protein profiling (revealed on a 2-DE map) of CAL-27 cells treated with 11-Epi-sinulariolide and that of CAL-27 cells without the treatment. A total of 28 differential proteins (12 up-regulated and 16 down-regulated) in CAL-27 cells treated with 11-Epi-sinulariolide have been identified by LC-MS/MS analysis. Some of the differential proteins are associated with cell proliferation, apoptosis, protein synthesis, protein folding, and energy metabolism. The results of this study provided clues for the investigation of biochemical mechanisms of the anti-tumor effects of 11-Epi-sinulariolide on CAL-27 cells and could be valuable information for drug development and progression monitoring of oral squamous cell carcinoma (OSCC).
