The anti-tumor effects of theonellasterol, an active ingredient isolated from Hippospongia sp, on CAL-27 cells were investigated in this study. In the MTT assay for cell proliferation, increasing concentrations of 11-dehydrosinulariolide decreased CAL-27 cell viability. When a concentration of 1.5 µg/mL of theonellasterol 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 theonellasterol increased. The results in this study indicated that treatment with theonellasterol for 6 h significantly induced both early and late apoptosis of CAL-27 cells, observed by flow cytometric measurement and microscopic fluorescent observation. The results of this study provided clues for the investigation of biochemical mechanisms of the anti-tumor effects of theonellasterol on CAL-27 cells and could be valuable information for drug development and progression monitoring of oral squamous cell carcinoma (OSCC).
