title: Lycopene induces cell growth inhibition by altering mevalonate pathway and Ras signaling in cancer cell lines.
abstract: Several evidences suggest that cancer cells have abnormal cholesterol biosynthetic pathways and prenylation of small guanosine triphosphatase proteins. Tomato lycopene has been suggested to have beneficial effects against certain types of cancer, including that of prostate, although the exact molecular mechanism(s) is unknown. We tested the hypothesis that lycopene may exert its antitumor effects through changes in mevalonate pathway and in Ras activation. Incubation of the Ras-activated prostatic carcinoma LNCaP cells with a 24 h lycopene treatment (2.5-10 μM) dose dependently reduced intracellular total cholesterol by decreasing 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase expression and by inactivating Ras, as evidenced by its translocation from cell membranes to cytosol. Concomitantly, lycopene reduced the Ras-dependent activation of nuclear factor-kappaB (NF-κB). Such a reduction was parallel to an inhibition of reactive oxygen species production and to a decrease in the phosphorylation ofc-jun N-terminal kinase, extracellular signal-regulated kinase 1/2 and p38. These effects were also accompanied by an arrest of cell cycle progression and by apoptosis induction, as evidenced by a decrease in cyclin D1 and phospho-AKT levels and by an increase in p21, p27 and p53 levels and in Bax:Bcl-2 ratio. The addition of mevalonate prevented the growth-inhibitory effects of lycopene as well as its increase in Ras cytoplasmatic accumulation and the subsequent changes in NF-κB. The ability of lycopene in inhibiting HMG-CoA reductase expression and cell growth and in inactivating Ras was also found in prostate PC-3, colon HCT-116 and HT-29 and lung BEN cancer cells. These findings provide a novel mechanistic insight into the growth-inhibitory effects of lycopene in cancer.
authors.affiliation: Institute of General Pathology, Catholic University School of Medicine, L. Go F. Vito, 00168 Rome, Italy. p.palozza@rm.unicatt.it
authors.forename: Paola
authors.initials: P
authors.lastname: Palozza
authors.forename: Maria
authors.initials: M
authors.lastname: Colangelo
authors.forename: Rossella
authors.initials: R
authors.lastname: Simone
authors.forename: Assunta
authors.initials: A
authors.lastname: Catalano
authors.forename: Alma
authors.initials: A
authors.lastname: Boninsegna
authors.forename: Paola
authors.initials: P
authors.lastname: Lanza
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monego
authors.forename: Franco O
authors.initials: FO
authors.lastname: Ranelletti
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002338:Carotenoids / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D000077276:Lycopene; D008297:Male; D008798:Mevalonic Acid / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018631:ras Proteins / Q000502:physiology*
chemical_list: D016588:Anticarcinogenic Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D002338:Carotenoids; D006903:Hydroxymethylglutaryl CoA Reductases; D018631:ras Proteins; D008798:Mevalonic Acid; D000077276:Lycopene