Cell killing and radiosensitization by caffeic acid phenethyl ester (CAPE) in lung cancer cells.
Caffeic acid phenethyl ester (CAPE) is a biologically active ingredient of honeybee propoplis. The cytotoxicity and radiation sensitization effects of CAPE were evaluated in human lung cancer A549 cells and normal lung fibroblast WI-38 cells. A549 cells treated with 6 microg/ml CAPE showed marked growth inhibition (60%) at 48 hr after treatments. During the same time, the number of viable cells decreased to 46% of the control value. In contrast, WI-38 cells showed 20% growth inhibition with no change in the number of viable cells under the same treatment conditions. At 72 hr after CAPE treatment (6 microg/ml), the percentage of apoptotic cells in A549 cultures increased significantly to 67% and an S/G2 arrest was also detected in the culture. Furthermore, there was a significant decrease in the level of intracellular glutathione and hydrogen peroxide contents within one hr after CAPE treatment, and the expression of cyclin B1 was reduced 6 hr after treatment. The radiation sensitization effect of CAPE on A549 cells was determined from the clonogenic survival curves, and the results showed a small but significant difference in radiation survival between cells treated with or without CAPE. Taken together, our results suggest that the effects of CAPE on differential cytotoxicity, apoptosis, and radiosensitization are associated with glutathione depletion that occurred shortly after treatments.
Chen
Miao-Fen
MF
Department of Radiation Oncology, Chang Gung Memorial Hospital, Chia-yi, Taiwan.
Wu
Chun-Te
CT
Chen
Yu-Jen
YJ
Keng
Peter C
PC
Chen
Wen-Cheng
WC
D000230:Adenocarcinoma / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D002109:Caffeic Acids / Q000494:pharmacology*; D002460:Cell Line / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D045744:Cell Line, Tumor / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology
D002109:Caffeic Acids; D011838:Radiation-Sensitizing Agents; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol