The latent membrane protein (LMP1) of Epstein–Barr virus (EBV) is expressed in EBV-associated nasopharyngeal carcinoma, which is notoriously metastatic. Although it is established that LMP1 represses E-cadherin expression and enhances the invasive ability of carcinoma cells, the mechanism underlying this repression remains to be elucidated. In this study, we demonstrate that LMP1 induces the expression and activity of the DNA methyltransferases 1, 3a, and 3b, using real-time reverse transcription–PCR and enzyme activity assay. This results in hypermethylation of the E-cadherin promoter and down-regulation of E-cadherin gene expression, as revealed by methylation-specific PCR, real-time reverse transcription–PCR and Western blotting data. The DNA methyltransferase inhibitor, 5′-Aza-2′dC, restores E-cadherin promoter activity and protein expression in LMP1-expressing cells, which in turn blocks cell migration ability, as demonstrated by the Transwell cell migration assay. Our findings suggest that LMP1 down-regulates E-cadherin gene expression and induces cell migration activity by using cellular DNA methylation machinery.

The miRNA participates in a variety of biologic processes, and dysregulation of miRNA is associated with malignant transformation. In this study, we determined specific profile of miRNA associated with oral cancer by using miRNA array screening method. There were 23 miRNAs found with considerably differential expressions between six oral cancer cell lines and five lines of normal oral keratinocytes, in which, 10 miRNAs showed the highest significant difference after independent examination by reverse transcription quantitative PCR. Eight molecules were upregulated, miR-10b, miR-196a, miR-196b, miR-582-5p, miR-15b, miR-301, miR-148b, and miR-128a, and two molecules, miR-503 and miR-31, were downregulated. The most upregulated miR-10b was further examined, and its functions were characterized in two oral cancer cell lines. The miR-10b actively promotes cell migration (2.6- to 3.6-fold) and invasion (1.7- to 1.9-fold) but has minimal effect on cell growth or chemo-/radiosensitivity. Furthermore, miR-10b was considerably elevated in the plasma of xenografted tumor mice (20-fold). This upregulation of miR-10b in plasma was further shown in the patients with oral cancer [P < 0.0001, area under curve (AUC) = 0.932] and precancer lesions (P < 0.0001, AUC = 0.967), suggesting that miR-10b possesses a high potential to discriminate the normal subjects. In conclusion, we have identified at least 10 miRNAs significantly associated with oral cancer, including the most elevated miR-10b. The miR-10b actively participates in cancer formation by promoting cell migration and invasion. Our study using clinical samples suggests that plasma miR-10b has high potential as an early detection marker for oral cancer. Cancer Prev Res; 5(4); 665–74. ©2012 AACR.

MicroRNAs (miRNAs) play important roles in tumorigenesis by regulating oncogenes and tumor-suppressor genes. In this study, miR-187 and miR-200a were found to be expressed at higher levels in ovarian cancers than in benign tumors. In patients with ovarian cancer, however, higher levels of miR-187 and miR-200a expression were paradoxically associated with better OS and recurrence-free survival. Further, multivariate analysis showed that miR-187 served as an independent prognostic factor for patients with ovarian cancer (n=176). Computational prediction and microarray results indicated that miR-187 directly targeted Disabled homolog-2 (Dab2), and luciferase reporter assays confirmed that the target site of miR-187 was located at the 3′-UTR of the Dab2 gene. Generally considered as a tumor-suppressor gene, Dab2 may actually promote tumor progression in advanced cancers through epithelial-to-mesenchymal transition (EMT). Ectopic expression of miR-187 in cancer cells promoted cell proliferation, but continued overexpression of miR-187 suppressed Dab2 and inhibited migration. Suppression of miR-187 upregulated Dab2, which, by inhibiting E-cadherin levels while stimulating vimentin and phospho-FAK levels, promoted EMT. Reduced ovarian cancer Dab2 histoscores correlated with high miR-187 levels and improved outcomes of patients. Collectively, these results demonstrate distinct dual roles of Dab2 in cell proliferation and tumor progression. In the initial steps of tumorigenesis, upregulated miR-187 suppresses Dab2, promoting cell proliferation. During the later stages, however, continued increased levels of miR-187 inhibits the Dab2-dependent EMT that is associated with tumor invasiveness, which is presumed to be the reason why cancers with high miR-187 levels were associated with better survivals.

Background. Norovirus and rotavirus cause outbreaks of diarrheal disease worldwide. This prospective observational study was undertaken to investigat

Mutations of KRAS/NRAS/BRAF predict cetuximab resistance in metastatic colorectal cancer patients

Backgrounds: Glucagon-like peptide-1 receptor agonist (GLP-1 RA) is probably one of more effective antidiabetic agents in treatment of type 2 diabetes mellitus (T2D). However, the heterogenicity in responses to GLP-1 RA may be potentially related to gut microbiota, although no human evidence has been published. This pilot study aims to identify microbial signatures associated with glycemic responses to GLP-1 RA.Materials and Methods: Microbial compositions of 52 patients with T2D receiving GLP-1 RA were determined by 16S rRNA amplicon sequencing. Bacterial biodiversity was compared between responders versus non-responders. Pearson’s correlation and random forest tree algorithm were used to identify microbial features of glycemic responses in T2D patients and multivariable linear regression models were used to validate clinical relevance.Results: Beta diversity significantly differed between GLP-1 RA responders (n = 34) and non-responders (n = 18) (ADONIS, P = 0.004). The top 17 features associated with glycohemoglobin reduction had a 0.96 diagnostic ability, based on area under the ROC curve: Bacteroides dorei and Roseburia inulinivorans, the two microbes having immunomodulation effects, along with Lachnoclostridium sp. and Butyricicoccus sp., were positively correlated with glycemic reduction; Prevotella copri, the microbe related to insulin resistance, together with Ruminococcaceae sp., Bacteroidales sp., Eubacterium coprostanoligenes sp., Dialister succinatiphilus, Alistipes obesi, Mitsuokella spp., Butyricimonas virosa, Moryella sp., and Lactobacillus mucosae had negative correlation. Furthermore, Bacteroides dorei, Lachnoclostridium sp. and Mitsuokella multacida were significant after adjusting for baseline glycohemoglobin and C-peptide concentrations, two clinical confounders.Conclusions: Unique gut microbial signatures are associated with glycemic responses to GLP-RA treatment and reflect degrees of dysbiosis in T2D patients.