Resveratrol causes WAF-1/p21-mediated G(1)-phase arrest of cell cycle and induction of apoptosis in human epidermoid carcinoma A431 cells.
Resveratrol (trans-3,4',5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a G(1)-phase arrest of the cell cycle followed by apoptosis of human epidermoid carcinoma (A431) cells. Resveratrol treatment (1-50 microM for 24 h) of A431 cells resulted in a dose-dependent (a) inhibition of cell growth as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, (b) G(1)-phase arrest of the cell cycle as shown by DNA cell cycle analysis, and (c) induction of apoptosis as assessed by ELISA. The immunoblot analysis revealed that resveratrol treatment causes a dose- and time-dependent (a) induction of WAF1/p21; (b) decrease in the protein expressions of cyclin D1, cyclin D2, and cyclin E; and (c) decrease in the protein expressions of cdk2, cdk4, and cdk6. Resveratrol treatment was also found to result in a dose- and time-dependent decrease in kinase activities associated with all of the cdks examined. Taken together, our study suggests that resveratrol treatment of the cells causes an induction of WAF1/p21 that inhibits cyclin D1/D2-cdk6, cyclin D1/D2-cdk4, and cyclin E-cdk2 complexes, thereby imposing an artificial checkpoint at the G(1)-->S transition of the cell cycle. This series of events results in a G(1)-phase arrest of the cell cycle, which is an irreversible process that ultimately results in the apoptotic death of cancer cells. To our knowledge, this is the first systematic study showing the involvement of each component of cdk inhibitor-cyclin-cdk machinery during cell cycle arrest and apoptosis of cancer cells by resveratrol.
Ahmad
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N
Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA. nxa3@po.cwru.edu
Adhami
V M
VM
Afaq
F
F
Feyes
D K
DK
Mukhtar
H
H
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis; D042846:CDC2-CDC28 Kinases; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D019938:Cyclin D1 / Q000037:antagonists & inhibitors; D056742:Cyclin D2; D019927:Cyclin E / Q000037:antagonists & inhibitors; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000037:antagonists & inhibitors / Q000502:physiology*; D016193:G1 Phase / Q000187:drug effects*; D006801:Humans; D010770:Phosphotransferases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; C080336:CCND2 protein, human; C493956:CDKN1A protein, human; D056742:Cyclin D2; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D013267:Stilbenes; D019938:Cyclin D1; D010770:Phosphotransferases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; C495911:CDK6 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases; D000077185:Resveratrol