RESUMO
Artesunate (ART) is a clinically approved antimalarial drug and was revealed as a candidate of colorectal cancer chemopreventive agents in our drug screening system. Here, we aimed to understand the suppressive effects of ART on intestinal tumorigenesis. In vitro, ART reduced T-cell factor/lymphoid enhancer factor (TCF/LEF) promoter transcriptional activity. In vivo, ART inhibited intestinal polyp development. We found that ART reduces TCF1/TCF7 nuclear translocation by binding the Ras-related nuclear protein (RAN), suggesting that ART inhibits TCF/LEF transcriptional factor nuclear translocation by binding to RAN, thereby inhibiting Wnt signaling. Our results provide a novel mechanism through which artesunate inhibits intestinal tumorigenesis.
Assuntos
Polipose Adenomatosa do Colo/prevenção & controle , Artesunato/farmacologia , Carcinogênese/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Via de Sinalização Wnt/efeitos dos fármacos , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Proteína da Polipose Adenomatosa do Colo/genética , Animais , Artesunato/uso terapêutico , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Técnicas de Silenciamento de Genes , Fator 1-alfa Nuclear de Hepatócito/genética , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Humanos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Transgênicos , Mutação , Regiões Promotoras Genéticas , Fator 1 de Transcrição de Linfócitos T/genética , Fator 1 de Transcrição de Linfócitos T/metabolismo , Ativação Transcricional/efeitos dos fármacos , Via de Sinalização Wnt/genética , Proteína ran de Ligação ao GTP/antagonistas & inibidores , Proteína ran de Ligação ao GTP/genética , Proteína ran de Ligação ao GTP/metabolismoRESUMO
Colorectal cancer is one of the leading causes of death worldwide. Reactive oxygen species produce oxidative stress and contribute to colorectal carcinogenesis. Because dietary citrus has been shown to reduce oxidative stress, we investigated the effects of citrus peel extract at dilutions of 1/200-1/500 on the activity of oxidative-stress-related transcription factors, including AP-1, NF-κB, NRF2, p53, and STAT3, in human colon cancer cell line HCT116 cells using a luciferase reporter gene assay. NRF2 transcriptional activities were 1.8- to 2.0-fold higher than the untreated control value. In addition, NF-κB, p53, and STAT3 transcriptional activities were 12-26% lower than the untreated control value. Administration of dried citrus peel in the diet of F344 rats at a dose of 1,000 ppm prevented the formation of azoxymethane-induced precancerous aberrant crypt foci (ACF) in the colon. The total number of ACF in rats fed with dried citrus peel was reduced to 75% of the control value. Moreover, the levels of oxidative-stress-related markers, reactive carbonyl species, in the serum of F344 rats were significantly reduced following the administration of dried citrus peel. These data suggest that citrus peel possesses an ability to suppress cellular oxidative stress through induction of NRF2, thereby preventing azoxymethane-induced colon carcinogenesis.