Melatonin reduces endothelin-1 expression and secretion in colon cancer cells through the inactivation of FoxO-1 and NF-κß.
J Pineal Res
; 56(4): 415-26, 2014 May.
Article
em En
| MEDLINE
| ID: mdl-24628039
ABSTRACT
Melatonin is an indoleamine that is synthesised from tryptophan under the control of the enzymes arylalkylamine N-acetyltransferase (AA-NAT) and acetylserotonin methyltransferase (ASMT). Melatonin inhibits colon cancer growth in both in vivo and in vitro models; however, a precise mechanism responsible for inhibiting tumour growth has not been clearly described. Endothelin-1 (ET-1) is a peptide that acts as a survival factor in colon cancer, inducing cell proliferation, protecting carcinoma cells from apoptosis and promoting angiogenesis. The data presented show that melatonin inhibits edn-1 mRNA expression (the first step in ET-1 synthesis), ECE-1 protein expression and the release of ET-1 from colorectal cancer cells in vitro. ET-1 levels in cultured media present a similar inhibition pattern to that of edn-1 mRNA expression despite the inhibition of ECE-1 protein after melatonin treatment, which suggests that an endopeptidase other than ECE-1 could be mainly responsible for ET-1 synthesis. The inhibition of edn-1 expression is due to an inactivation of FoxO1 and NF-κß transcription factors. FoxO1 inactivation is associated with an increased Src phosphorylation, due to elevated cAMP content and PKA activity, whereas NF-κß inactivation is associated with the blockade of Akt and ERK phosphorylation due to the inhibition of PKC activity after melatonin treatment. Melatonin also inhibits edn-1 promoter activity regulated by FoxO1 and NF-κß. Finally, a significant correlation was observed between AA-NAT and edn-1 expression downregulation in human colorectal cancer tissues. In conclusion, melatonin may be useful in treating colon carcinoma in which the activation of ET-1 plays a role in tumour growth and progression.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Regulação Neoplásica da Expressão Gênica
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NF-kappa B
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Neoplasias do Colo
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Endotelina-1
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Fatores de Transcrição Forkhead
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Melatonina
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Pineal Res
Ano de publicação:
2014
Tipo de documento:
Article