[Apoptosis in nasopharyngeal carcinoma cell line NCE induced by curcumin and its molecular mechanism].
OBJECTIVE
To investigate the mechanism underlying the curcumin-induced apoptosis of nasopharyngeal carcinoma (NPC) cell line NCE cells.


METHODS
The characteristics of apoptosis were identified by observation acridine orange and ethidium bromide stains, ultrastructure assay, DNA fragmentation assay and TdT-mediated dUTP nick end labeling method (TUNEL). Mitochondrial membrane potential (delta psi m), activity of caspase-3, cytosol cytochrome C and expression of gene Fas were determined by flow cytometry (FCM), Western Blot and reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
Several evidences of apoptosis were obtained from curcumin-treated NCE cells by acridine orange and ethidium bromide stains, ultrastructure identification, DNA fragmentation assay and TUNEL staining. And the mean TUNEL-positive rates increased significantly at the 3 different time points (12 h, 24 h and 48 h; 25.6%, 40.3% and 54.5%, respectively). In the curcumin-treated-groups, delta psi m altered significantly and the positive rates increased in a time-dependent manner. At the 3 different time points, the mean positive rates were 26.8%, 42.3% and 68.2%, respectively. When caspase-3 activity was detected, 80.5% cells presented proteases activities after 12 h incubation with curcumin. Western Blot analysis showed that cytoplasmic cytochrome C increased significantly after incubation with curcumin. Flow cytometry and RT-PCR analysis showed that curcumin could up-regulate the Fas expression in time-depended manner , the positive rates of Fas protein increased from 33.6% to 89.9%.


CONCLUSIONS
Curcumin induced apoptosis of NCE cells both through mitochondria-dependent pathway and death receptor pathway.
Yang
Fu-wen
FW
Department of Otorhinolaryngology, Zhujiang Hospital, Nanfang Medical University, Guangzhou 510280, China. puwenyang@163.com
Huang
Jin-zhong
JZ
Lin
Xiao-lan
XL
Zhen
Ze-nian
ZN
Chen
Xian-ming
XM
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D003474:Curcumin / Q000494:pharmacology*; D006801:Humans; D053078:Membrane Potential, Mitochondrial; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology*; D019014:fas Receptor / Q000378:metabolism
D019014:fas Receptor; D053148:Caspase 3; D003474:Curcumin