Caffeic acid phenethyl ester (CAPE), a component of propolis, was reported to possess anti-inflammatory, anti-bacterial, anti-viral, and anti-tumor activities. Our aim was to investigate the effect of CAPE on apoptosis in cultured human mucoepidermoid carcinoma (MEC) cell line, MC-3. Apoptotic effects of CAPE were measured by cell viability assays, Western blotting, 4’-6-diamidino-2-phenylindole (DAPI) staining and Live/Dead assay. The result of cell viability assay showed that CAPE displayed a strong growth-inhibitory effect in a concentration-dependent manner against MC-3 cells. Consumption of CAPE resulted in pronounced increase in the cleavage of caspase-3 and PARP, induced nuclear condensation and fragmentation and clearly increased the number of dead cells in MC-3 cells. CAPE also caused the increase in truncated Bid (t-Bid) and the cleavage of caspase-8 and this phenomenon was regulated by death receptor 5 (DR5). In addition, Phosphorylation of AKT and ERK were downregulated by CAPE. Taken together, these results suggest that CAPE is a potent apoptosis-inducing agent in MC-3 cells.

Ⅰ. INTRODUCTION
 Ⅱ. MATERIALS AND METHODS
  1. Cell culture and chemical treatment
  2. Antibodies
  3. Cell viability assay
  4. DAPI staining
  5. Live/Dead assay
  6. Western blot analysis
  7. Statistical analysis
 Ⅲ. RESULTS
  1. CAPE reduces cell viability and causesapoptosis and cytotoxicity in MC-3 cells
  2. Extrinsic apoptotic pathway is involved inCAPE-mediated apoptosis and it also activatesAKT and ERK signaling in MC-3 cells
 IV. DISCUSSION
 V. REFERENCES

• 유현주(Department of Oral Pathology, School of Dentistry, and Institute of Oral Bioscience, Institute of Biodegradable material, Chonbuk National University) | Hyun Ju Yu
• 조남표(Department of Oral Pathology, School of Dentistry, and Institute of Oral Bioscience, Institute of Biodegradable material, Chonbuk National University) | Nam Pyo Cho
• 조성대(Department of Oral Pathology, School of Dentistry, and Institute of Oral Bioscience, Institute of Biodegradable material, Chonbuk National University) | Sung Dae Cho correspondence