Induction of apoptosis in human leukemia cells by grape seed extract occurs via activation of c-Jun NH2-terminal kinase.
OBJECTIVE
To characterize the functional role of c-Jun NH(2)-terminal kinase (JNK) and other apoptotic pathways in grape seed extract (GSE)-induced apoptosis in human leukemia cells by using pharmacologic and genetic approaches.


METHODS
Jurkat cells were treated with various concentrations of GSE for 12 and 24 h or with 50 microg/mL GSE for various time intervals, after which apoptosis, caspase activation, and cell signaling pathways were evaluated. Parallel studies were done in U937 and HL-60 human leukemia cells.


RESULTS
Exposure of Jurkat cells to GSE resulted in dose- and time-dependent increase in apoptosis and caspase activation, events associated with the pronounced increase in Cip1/p21 protein level. Furthermore, treatment of Jurkat cells with GSE resulted in marked increase in levels of phospho-JNK. Conversely, interruption of the JNK pathway by pharmacologic inhibitor (e.g., SP600125) or genetic (e.g., small interfering RNA) approaches displayed significant protection against GSE-mediated lethality in Jurkat cells.


CONCLUSIONS
The result of the present study showed that GSE induces apoptosis in Jurkat cells through a process that involves sustained JNK activation and Cip1/p21 up-regulation, culminating in caspase activation.
Gao
Ning
N
Department of Pharmacognosy, School of Pharmacy, 3rd Military Medical University, Chongqing, People's Republic of China.
Budhraja
Amit
A
Cheng
Senping
S
Yao
Hua
H
Zhang
Zhuo
Z
Shi
Xianglin
X
D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004789:Enzyme Activation; D056604:Grape Seed Extract; D018922:HL-60 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000096:biosynthesis*; D019169:Jurkat Cells; D007938:Leukemia / Q000473:pathology*; D010936:Plant Extracts; D044945:Proanthocyanidins; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation
D000873:Anthracenes; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D056604:Grape Seed Extract; C511402:Grape Seed Proanthocyanidins; D010936:Plant Extracts; D044945:Proanthocyanidins; D034741:RNA, Small Interfering; C432165:pyrazolanthrone; D048031:JNK Mitogen-Activated Protein Kinases