Lycopene inhibition of cell cycle progression in breast and endometrial cancer cells is associated with reduction in cyclin D levels and retention of p27(Kip1) in the cyclin E-cdk2 complexes.
Numerous studies have demonstrated the anticancer activity of the tomato carotenoid, lycopene. However, the molecular mechanism of this action remains unknown. Lycopene inhibition of human breast and endometrial cancer cell growth is associated with inhibition of cell cycle progression at the G(1) phase. In this study we determined the lycopene-mediated changes in the cell cycle machinery. Cells synchronized in the G(1) phase by serum deprivation were treated with lycopene or vehicle and restimulated with 5% serum. Lycopene treatment decreased serum-induced phosphorylation of the retinoblastoma protein and related pocket proteins. This effect was associated with reduced cyclin-dependent kinase (cdk4 and cdk2) activities with no alterations in CDK protein levels. Lycopene caused a decrease in cyclin D1 and D3 levels whereas cyclin E levels did not change. The CDK inhibitor p21(Cip1/Waf1) abundance was reduced while p27(Kip1) levels were unaltered in comparison to control cells. Serum stimulation of control cells resulted in reduction in the p27 content in the cyclin E--cdk2 complex and its accumulation in the cyclin D1--cdk4 complex. This change in distribution was largely prevented by lycopene treatment. These results suggest that lycopene inhibits cell cycle progression via reduction of the cyclin D level and retention of p27 in cyclin E--cdk2, thus leading to inhibition of G(1) CDK activities.
Nahum
A
A
Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Hirsch
K
K
Danilenko
M
M
Watts
C K
CK
Prall
O W
OW
Levy
J
J
Sharoni
Y
Y
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D042846:CDC2-CDC28 Kinases; D002338:Carotenoids / Q000494:pharmacology*; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D056741:Cyclin D; D019927:Cyclin E / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism* / Q000502:physiology*; D016889:Endometrial Neoplasms / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005312:Fetal Blood / Q000502:physiology; D016193:G1 Phase / Q000187:drug effects*; D006801:Humans; D000077276:Lycopene; D046911:Macromolecular Substances; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D016588:Anticarcinogenic Agents; C493956:CDKN1A protein, human; D016895:Culture Media, Serum-Free; D056741:Cyclin D; D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; C493837:RBL2 protein, human; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D002338:Carotenoids; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D000077276:Lycopene