RESUMO
Previous studies have shown that miR-454 plays an important role in a variety of biological processes in various human cancer cells. However, the underlying mechanisms of this microRNA in colorectal cancer (CRC) cells remain largely unknown. In the present study, we investigated the miR-454 role in CRC cell proliferation. We found that miR-454 expression is markedly upregulated in CRC tissues and CRC cells compared with the matched tumor adjacent tissues and the FHC normal colonic cell line. Ectopic expression of miR-454 promoted the proliferation and anchorage-independent growth of CRC cells, whereas inhibition of miR-454 reduced this effect. Bioinformatics analysis further revealed cylindromatosis (CYLD), a putative tumor suppressor as a potential target of miR-454. Data from luciferase reporter assays showed that miR-454 directly binds to the 3'-untranslated region (3'-UTR) of CYLD mRNA and repressed expression at both transcriptional and translational levels. In functional assays, CYLD-silenced in miR-454-in-transfected SW480 cells have positive effect to promote cell proliferation, suggesting that direct CYLD downregulation is required for miR-454-induced CRC cell proliferation. In sum, our data provide compelling evidence that miR-454 functions as an onco-miRNA, playing a crucial role in the promoting cell proliferation in CRC, and its oncogenic effect is mediated chiefly through direct suppression of CYLD expression.
Assuntos
Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Proteínas Supressoras de Tumor/antagonistas & inibidores , Regiões 3' não Traduzidas , Apoptose , Western Blotting , Adesão Celular , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Enzima Desubiquitinante CYLD , Humanos , Técnicas Imunoenzimáticas , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
AIM: To compare matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 in gastric ulcer (GU) and chronic superficial gastritis (CSG). METHODS: This study enrolled 63 patients with GU and 25 patients with CSG. During upper gastroduodenal endoscopy, we took samples of gastric mucosa from the antrum and ulcer site from patients with GU, and samples of antral mucosa from patients with CSG. Mucosal biopsy tissues were cultured for 24 h, and the culture supernatant was measured for levels of MMP-9 and TIMP-1. After receiving eradication therapy for Helicobacter pylori (H. pylori) and 8 wk proton-pump inhibitor therapy for GU, follow-up endoscopy examination was performed after 6 mo and whenever severe symptoms occurred. RESULTS: Levels of MMP-9 and TIMP-1 at the ulcer site or in the antrum were significantly higher in GU than CSG patients. MMP-9 levels at the ulcer site were significantly higher than in the antrum in GU patients, and had a significantly positive correlation with TIMP-1. MMP-9 levels were significantly higher in H. pylori-positive than H. pylori-negative GU and CSG patients. Levels of MMP-9 or TIMP-1 at the ulcer site were associated with the histological severity of activity and inflammation. About 57 GU patients were followed up, and seven had GU recurrence. H. pyloriinfection and MMP-9 levels were risk factors for the recurrence of GU adjusted for age and sex by multiple logistic regression analysis. CONCLUSION: MMP-9 may perform an important function in gastric ulcer formation and recurrence.