RESUMO
Our previous work has demonstrated that the role of miR-93 in prostate cancer (PC) progression. The aim of this study was to determine the downstream gene regulated by miR-93 and the molecular mechanisms underlying its roles in PC. Bioinformatics analysis and luciferase reporter assays predicted disabled homolog 2 (DAB2) as a direct target gene of miR-93. Real time quantitative polymerase chain reaction (qRT-PCR) and Western blot analysis revealed that DAB2 was tumor repressor in PC cells, and its mRNA expression was negatively correlated with miR-93 in PC tissues. Gain and loss of function experiments also indicated DAB2 overexpression significantly suppressed PC cells proliferation, invasion and migration, while knockdown of its expression came to the opposite effect. Furthermore, a rescue experiment indicated miR-93 directly regulated PC cell growth and migration, as well as AKT and ERK activation by targeting DAB2. Additionally, antitumor effect of a Green tea polysaccharide (GTP) on PC-3 cells could be achieved by increasing DAB2 protein expression and inactivating AKT and ERK1/2 signaling. Our study suggests that miR-93 promoted PC progression and metastasis by repressing DAB2 to activate Akt/ERK1/2 pathway, and elevation of DAB2 and inactivation of Akt/ERK1/2 might be a potential therapeutic target for PC by GTP.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Antineoplásicos/farmacologia , Camellia sinensis/química , MicroRNAs/genética , Polissacarídeos/farmacologia , Neoplasias da Próstata/genética , Chá/química , Proteínas Supressoras de Tumor/genética , Proteínas Reguladoras de Apoptose , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Células PC-3 , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genéticaRESUMO
In this study, a homogeneous polysaccharide (GTP), with a molecular weight of 7.0â¯×â¯104â¯Da, was isolated from Green tea, which was only composed of glucose. The antitumor effects of GTP on prostate cancer (PC) cell line along with the possible mechanism was examined. First, we investigate the potential role of microRNA-93 (miR-93) in PC progression. Our results showed that miR-93 was significantly upregulated in human PC tissues and several PC cell lines, and its overexpression was correlated with poor survival in PC patients. Furthermore, functional analysis showed that miR-93 overexpression promoted the migration, invasion and proliferation of PC-3 cells transfected with miR-93 mimics, while its knockdown displayed an opposite result in DU145 cells following miR-93 inhibitor transfection. Additionally, in vivo tumorigenic studies on nude mice confirmed that miR-93 mimic treatment accelerated the growth of PC-3 xenograft tumors. As expected, GTP (25, 50 and 100⯵g/ml) inhibited growth of PC-3 cells via inducing apoptosis, which was achieved by elevation of bax/bcl-2 ratio and caspae-3 protein expression, as well as a decrease of miR-93. Thus, miR-93 may be a potential therapeutic target by GTP for PC therapy.
