Gut microbiota dysbiosis contributes to the onset and perpetuation of inflammatory bowel disease (IBD). Given that gut microbiotas vary across geography and ethnicity, it remains obscure whether any universal microbial signatures for IBD diagnosis and prognosis evaluation exist irrespective of populations. Here we profiled the fecal microbiota of a series of Chinese IBD patients and combined them with two Western IBD cohorts, PRISM and RISK, for meta-analyses. We found that the gut microbial alteration patterns in IBD are similar among Chinese and Westerners. Our prediction model based on gut microbiome for IBD diagnosis is robust across the cohorts, which showed 87.5% and 79.1% prediction accuracy in Crohn's disease (CD) and ulcerative colitis (UC) patients, respectively. A relative increase in the levels of Actinobacteria and Proteobacteria (Enterobacteriaceae) and a relative decrease in the levels of Firmicutes (Clostridiales) were strongly correlated with IBD severity (P Ͻ 0.05). Additionally, restoration of gut microbiota diversity and a significant increase in Clostridiales relative abundance were found in patients responding to infliximab (IFX [Remicade]) treatment compared to those in relapse. Moreover, certain microbes, mainly Clostridiales, predicted the treatment effectiveness with 86.5% accuracy alone and 93.8% accuracy in combination with calprotectin levels and Crohn's disease activity index (CDAI). Taking the results together, we conclude that gut microbiota can offer a set of universal biomarkers for diagnosis, disease activity evaluation, and infliximab treatment response prediction in IBD. IMPORTANCEIn the present report, we show that the human fecal microbiota contains promising and universal biomarkers for the noninvasive evaluation of inflammatory bowel disease severity and IFX treatment efficacy, emphasizing the potential

It is well recognized that hypoxia-inducible factor 1 alpha (HIF-1α) is involved in cancer metastasis, chemotherapy and poor prognosis. We previously found that deferoxamine, a hypoxia-mimetic agent, induces epithelial-mesenchymal transition (EMT) in colorectal cancer. Therefore, here we explored a new molecular mechanism for HIF-1α contributing to EMT and cancer metastasis through binding to ZEB1. In this study, we showed that overexpression of HIF-1α with adenovirus infection promoted EMT, cell invasion and migration in vitro and in vivo. On a molecular level, HIF-1α directly binding to the proximal promoter of ZEB1 via hypoxia response element (HRE) sites thus increasing the transactivity and expression of ZEB1. In addition, inhibition of ZEB1 was able to abrogate the HIF-1α-induced EMT and cell invasion. HIF-1α expression was highly correlated with the expression of ZEB1 in normal colorectal epithelium, primary and metastatic CRC tissues. Interestingly, both HIF-1α and ZEB1 were positively associated with Vimentin, an important mesenchymal marker of EMT, whereas negatively associated with E-cadherin expression. These findings suggest that HIF-1α enhances EMT and cancer metastasis by binding to ZEB1 promoter in CRC. HIF-1α and ZEB1 are both widely considered as tumor-initiating factors, but our results demonstrate that ZEB1 is a direct downstream of HIF-1α, suggesting a novel molecular mechanism for HIF-1α-inducing EMT and cancer metastasis.

Background: Long noncoding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides in length. They drive many important cancer phenotypes through their interactions with other cellular macromolecules including DNA, RNA and protein. Recent studies have identified numerous lncRNAs active in colorectal cancer (CRC). The lncRNA small nucleolar RNA host gene 6 (SNHG6) has been reported to have an oncogenic role in multiple cancers. However, the biological role and mechanism of SNHG6 in the tumorigenesis of CRC has not been reported in-deep.Methods: The Cancer Genome Atlas (TCGA) database and GEO database were used to identify SNHG6 expression in different human cancers and explore the relationship between SNHG6 expression and patient prognosis using Kaplan-Meier method analysis. SNHG6 expression in 77 pairs of clinical CRC tissues and different CRC cell lines were analyzed by quantitative real-time PCR (qRT-PCR). A CCK-8 assay was used to assess cell proliferation, transwell assay to detect the cell metastasis, and tumor growth was investigated with a nude mice model in vivo. Whether UPF1 and ZEB1 are downstream targets of SNHG6 was verified by bioinformatics target gene prediction, qRT-PCR and western blot.Results: TCGA data showed that SNHG6 was significantly upregulated in colorectal cancer samples in comparison with healthy data samples (P < 0.01). CRC patients with high levels of SNHG6 had a significantly shorter overall survival than those with low levels of SNHG6 (P = 0.0162). qRT-PCR confirmed that the expression of SNHG6 was significantly upregulated in CRC tissues and cell lines. Upregulation of SNHG6 expression induced RKO and HCT116 cell proliferation as well as RKO cell metastasis, while downregulation of SNHG6 expression supressed the proliferation and metastasis of RKO cells and tumor growth in vivo. UPF1 was upregulated and ZEB1 was decreased when SNHG6 knockdown, regulating the TGF-β/Smad pathway and inducing EMT respectively.Conclusions: SNHG6 may play an oncogenic role in CRC cells by activating TGF-β/Smad signaling pathway via targeting of UPF1 and inducing EMT via regulating ZEB1. This could be a prognostic biomarker and therapeutic target for CRC.