SP1 mediates the link between methylation of the tumour suppressor miR-149 and outcome in colorectal cancer.

Although recent studies indicate that DNA methylation contributes to the down-regulation of microRNAs (miRNAs) in colorectal cancer (CRC), this field remains largely unexplored. To identify methylation-silenced miRNAs and clarify their role in CRC, we performed a microarray analysis and screened for miRNAs that were induced in CRC cells by 5-aza-2'-deoxycytidine treatment or by the knockdown of DNA methyltransferases. The DNA methylation status of the candidate miRNA was analysed by bisulphite sequencing PCR and methylation-specific PCR. We found that miRNA-149 (miR-149) was epigenetically silenced in CRC and down-regulation of miR-149 was associated with hypermethylation of the neighbouring CpG island (CGI). Quantitative RT-PCR analysis demonstrated that the miR-149 level was markedly reduced in 51.6% of the CRC tissues compared with matched non-cancerous tissues. In addition, low expression of miR-149 was associated with a greater depth of invasion (p = 0.012), lower 5-year survival rate (p = 0.025), and was found to be an independent prognostic factor for overall survival (p = 0.016) in a multivariate analysis. Moreover, transfection of miR-149 inhibited cell growth and invasion of CRC cells in vitro. We also identified mRNA for Specificity Protein 1 (SP1, Sp1), a potential oncogenic protein, as a target of miR-149. Our data suggest that, as a methylation-sensitive miRNA, miR-149 may play an important role as a tumour suppressor in CRC, which has prognostic and therapeutic implications.

UHRF1 promotes cell growth and metastasis through repression of p16(ink4a) in colorectal cancer.

PURPOSE: To investigate whether ubiquitin-like with plant homeodomain and ring finger domains 1 (UHRF1) expression is upregulated in colorectal cancer (CRC), whether UHRF1 promotes CRC cell growth and migration and the underlying molecular mechanism. METHODS: UHRF1 protein expression was determined in 144 pairs of primary CRC and their corresponding adjacent nontumor tissues by immunohistochemistry with tissue microarrays. UHRF1 mRNA expression was assessed in 20 pairs of the above tissues and four colon cancer cell lines by quantitative reverse transcriptase-polymerase chain reaction. Associations of UHRF1 expression with demographic and clinicopathologic features were determined. Additionally, the effects of lentiviral-mediated RNA interference (RNAi) of UHRF1 on cell proliferation and migration, cell cycle and apoptosis, and the expression of p16(ink4a) and p21(waf1/cip1) were investigated in CRC cell lines. RESULTS: UHRF1 was overexpressed in CRC tissues and cell lines. UHRF1 protein expression levels correlated with the presence of lymph nodes (P = 0.005), distal metastasis (P = 0.030), poor Dukes staging (P = 0.001), and absence of p16(ink4a) expression (P = 0.002). RNAi of UHRF1 inhibited proliferation and migration, and induced apoptosis and cell cycle arrest at the G0/G1 phase. Furthermore, RNAi of UHRF1 enhanced the expression of p16(ink4a), but not p21(waf1/cip1), in CRC cells. CONCLUSIONS: UHRF1 expression is upregulated in CRC and is associated with the progression of CRC. Moreover, RNAi of UHRF1 decreases proliferation and migration but enhances apoptosis of CRC cells, with increased p16(ink4a) expression. UHRF1 promotes CRC growth and metastasis, likely by repressing p16(ink4a), and thus it may be used as a biomarker or even a therapeutic target for CRC.

Alternative splicing of VEGFA, APP and NUMB genes in colorectal cancer.

AIM: To investigate alternative splicing in vascular endothelial growth factor A (VEGFA), amyloid beta precursor protein (APP), and Numb homolog (NUMB) in colorectal cancer (CRC). METHODS: Real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and PCR-restriction fragment length polymorphism analyses were performed to detect the expression of VEGFA, APP, and NUMB mRNA in 20 CRC tissues and matched adjacent normal tissues, as well as their alternative splicing variants. RESULTS: qRT-PCR analysis revealed that the expression of APP, NUMB, and VEGFA165b mRNA were significantly downregulated, while VEGFA mRNA was upregulated, in CRC tissues (all P < 0.05). PCR-restriction fragment length polymorphism analysis revealed that the expression of VEGFA165a/b in CRC tissues was significantly higher than in adjacent normal tissues (P < 0.05). Compared with adjacent normal tissues, the expression of NUMB-PRR(S) in CRC tissues was significantly decreased (P < 0.05), and the expression of NUMB-PRR(L) was increased (P < 0.05). CONCLUSION: Alternative splicing of VEGFA, APP, and NUMB may regulate the development of CRC, and represent new targets for its diagnosis, prognosis, and treatment.

Effect of Lactobacillus plantarum on Intestinal Infection in Multiple Drug-Resistant Bacteria Mice.

BACKGROUND: This study aimed to determine the effects of probiotic Lactobacillus plantarum on colitis in mice with multiple drug-resistant bacteria, and to judge the intervention function of probiotics in the resistance of pathogenic bacteria. METHODS: Male BALB/C mice were divided into four groups. The colonic tissues were collected for pathology observation, permeability, transepithelial electrical resistance (TER), and tight junction protein expression detection at death, and the feces were collected for detecting drug susceptibility of MDR-PA. RESULTS: MDR-PA mice developed severe intestinal inflammation and tissue damage in which paracellular permeability was increased, in conjunction with decreased expression and redistribution. LP administration attenuated colitis of MDR-PA mice. The drug susceptibility diameter of MDR-PA has increased. CONCLUSION: Probiotics can treat diarrhea of mice by MDR-PA and protect the intestinal barrier function. Probiotics can weaken the resistance of multiple drug resistance in Pseudomonas aeruginosa to some extent.

Combined probiotic bacteria promotes intestinal epithelial barrier function in interleukin-10-gene-deficient mice.

AIM: To investigate the protective effects of combinations of probiotic (Bifico) on interleukin (IL)-10-gene-deficient (IL-10 KO) mice and Caco-2 cell monolayers. METHODS: IL-10 KO mice were used to assess the benefits of Bifico in vivo. IL-10 KO and control mice received approximately 1.5 × 10(8) cfu/d of Bifico for 4 wk. Colons were then removed and analyzed for epithelial barrier function by Ussing Chamber, while an ELISA was used to evaluate proinflammatory cytokines. The colon epithelial cell line, Caco-2, was used to test the benefit of Bifico in vitro. Enteroinvasive Escherichia coli (EIEC) and the probiotic mixture Bifico, or single probiotic strains, were applied to cultured Caco-2 monolayers. Barrier function was determined by measuring transepithelial electrical resistance and tight junction protein expression. RESULTS: Treatment of IL-10 KO mice with Bifico partially restored body weight, colon length, and epithelial barrier integrity to wild-type levels. In addition, IL-10 KO mice receiving Bifico treatment had reduced mucosal secretion of tumor necrosis factor-α and interferon-γ, and attenuated colonic disease. Moreover, treatment of Caco-2 monolayers with Bifico or single-strain probiotics in vitro inhibited EIEC invasion and reduced the secretion of proinflammatory cytokines. CONCLUSION: Bifico reduced colon inflammation in IL-10 KO mice, and promoted and improved epithelial-barrier function, enhanced resistance to EIEC invasion, and decreased proinflammatory cytokine secretion.