Fecal Signatures of Streptococcus anginosus and Streptococcus constellatus for Noninvasive Screening and Early Warning of Gastric Cancer.

BACKGROUND & AIMS: Most patients with gastric cancer (GCa) are diagnosed at an advanced stage. We aimed to investigate novel fecal signatures for clinical application in early diagnosis of GCa. METHODS: This was an observational study that included 1043 patients from 10 hospitals in China. In the discovery cohort, 16S ribosomal RNA gene analysis was performed in paired samples (tissues and feces) from patients with GCa and chronic gastritis (ChG) to determine differential abundant microbes. Their relative abundances were detected using quantitative real-time polymerase chain reaction to test them as bacterial candidates in the training cohort. Their diagnostic efficacy was validated in the validation cohort. RESULTS: Significant enrichments of Streptococcus anginosus (Sa) and Streptococcus constellatus (Sc) in GCa tumor tissues (P < .05) and feces (P < .0001) were observed in patients with intraepithelial neoplasia, early and advanced GCa. Either the signature parallel test Sa∪Sc or single signature Sa/Sc demonstrated superior sensitivity (Sa: 75.6% vs 72.1%, P < .05; Sc: 84.4% vs 64.0%, P < .001; and Sa∪Sc: 91.1% vs 81.4%, P < .01) in detecting early GCa compared with advanced GCa (specificity: Sa: 84.0% vs 83.9%, Sc: 70.4% vs 82.3%, and Sa∪Sc: 64.0% vs 73.4%). Fecal signature Sa∪Sc outperformed Sa∪CEA/Sc∪CEA in the discrimination of advanced GCa (sensitivity: 81.4% vs 74.2% and 81.4% vs 72.3%, P < .01; specificity: 73.4% vs 81.0 % and 73.4% vs 81.0%). The performance of Sa∪Sc in the diagnosis of both early and advanced GCa was verified in the validation cohort. CONCLUSION: Fecal Sa and Sc are noninvasive, accurate, and sensitive signatures for early warning in GCa. (ClinicalTrials.gov, Number: NCT04638959).

Spinal anesthesia alleviates dextran sodium sulfate-induced colitis by modulating the gut microbiota.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic disease with recurrent intestinal inflammation. Although the exact etiology of IBD remains unknown, the accepted hypothesis of the pathogenesis to date is that abnormal immune responses to the gut microbiota are caused by environmental factors. The role of the gut microbiota, particularly the bidirectional interaction between the brain and gut microbiota, has gradually attracted more attention. AIM: To investigate the potential effect of spinal anesthesia on dextran sodium sulfate (DSS)-induced colitis mice and to detect whether alterations in the gut microbiota would be crucial for IBD. METHODS: A DSS-induced colitis mice model was established. Spinal anesthesia was administered on colitis mice in combination with the methods of cohousing and fecal microbiota transplantation (FMT) to explore the role of spinal anesthesia in IBD and identify the potential mechanisms involved. RESULTS: We demonstrated that spinal anesthesia had protective effects against DSS-induced colitis by alleviating clinical symptoms, including reduced body weight loss, decreased disease activity index score, improved intestinal permeability and colonic morphology, decreased inflammatory response, and enhanced intestinal barrier functions. Moreover, spinal anesthesia significantly increased the abundance of Bacteroidetes, which was suppressed in the gut microbiota of colitis mice. Interestingly, cohousing with spinal anesthetic mice and FMT from spinal anesthetic mice can also alleviate DSS-induced colitis by upregulating the abundance of Bacteroidetes. We further showed that spinal anesthesia can reduce the increase in noradrenaline levels induced by DSS, which might affect the gut microbiota. CONCLUSION: These data suggest that microbiota dysbiosis may contribute to IBD and provide evidence supporting the protective effects of spinal anesthesia on IBD by modulating the gut microbiota, which highlights a novel approach for the treatment of IBD.

Upregulation of PD-L1 predicts poor prognosis and is associated with miR-191-5p dysregulation in colon adenocarcinoma.

Targeting of the programmed cell-death 1 ligand 1 (PD-L1) signal pathway is a promising treatment strategy in several cancers. The purpose of this study was to evaluate the clinical significance of PD-L1 in patients with colon adenocarcinoma (COAD). A total of 240 patients who were diagnosed with COAD from The Cancer Genome Atlas (TCGA) RNA-sequencing data and another cohort for pair-matched COAD samples (n = 40) in tissue microarray (TMA) were enrolled in this study. The correlation of PD-L1 or miR-191-5p expression with clinicopathological features and prognosis in patients with COAD was further analyzed using TCGA data and TMA. The Cox proportional hazard regression model was used to evaluate the association of PD-L1 or miR-191-5p expression with overall survival (OS) and tumor recurrence in patients with COAD. The microRNAs (miRNAs) that target PD-L1 gene were identified by bioinformatics and Spearman correlation analysis. We found that PD-L1 expression was increased in COAD tissues and was correlated with poor survival and tumor recurrence in patients with COAD. The increased expression of PD-L1 was attributed to the dysregulation of miR-191-5p expression rather than its genetic or epigenetic alterations. Moreover, the expression of miR-191-5p presented the negative correlation with PD-L1 expression and acted as an independent prognostic factor of OS in patients with COAD. Therefore, PD-L1 may predict poor prognosis and is negatively associated with miR-191-5p expression in patients with COAD.

Circular RNAs: An emerging type of RNA in cancer.

Circular RNAs (circRNAs), a novel type of widespread and diverse endogenous non-coding RNAs (ncRNAs), which are different from the linear RNAs, form a covalently closed continuous loop without 5' or 3' polarities. The majority of circRNAs are abundant, conserved and stable across different species, and exhibit tissue/developmental-stage-specific characteristics. They are generated primarily through a type of alternative RNA splicing called "back-splicing," in which a downstream splice donor is joined to an upstream splice acceptor through splice skipping or direct splice. Recent studies have discovered circRNAs function as microRNA sponges, binding with RNA-associated proteins to form RNA-protein complexes and then regulating gene transcription and translation into polypeptides. Emerging evidence indicates that circRNAs play important roles in the regulation of the development and progression of multiple cancers by serving as potential diagnostic and predictive biomarkers involved in tumor growth and invasion and providing new strategies for cancer diagnosis and targeted therapy. In this review, we briefly delineate the diversity and characteristics of circRNAs and discuss the highlights of the biogenesis of circRNAs and their potential functions in tumor.

Toosendanin suppresses oncogenic phenotypes of human gastric carcinoma SGC­7901 cells partly via miR­200a­mediated downregulation of ß-catenin pathway.

Aberrant activation of ß-catenin signaling due to low expression of miR­200a is found in gastric carcinoma (GC) tissues promoting GC evolution. Toosendanin (TSN) has exhibited antitumor effects on various human cancer cells, but its influence on GC is largely unidentified. The potential roles of TSN on GC cells were examined and it was found that TSN inhibited growth, migration, invasion and TGF­ß1-induced epithelial-mesenchymal transition (EMT) and induced cell cycle arrest and apoptosis in SGC­7901 cells which were most sensitive to TSN among various GC cell lines. TSN also inactivated ß-catenin pathway in SGC­7901 cells and the above effects were reversed following induction of ß-catenin overexpression. Moreover, TSN facilitated the level of miR­200a which targets ß-catenin and miR­200a silencing attenuated the antitumor effects of TSN on SGC­7901 cells. Nonetheless, knockdown of miR­200a did not relieve the suppressive effects of TSN on p­AKT, p­ERK and p­GSK3ß which were upstream regulators of ß-catenin. In addition, TSN administration inhibited growth and liver metastasis of orthotopically implanted SGC­7901 tumors in vivo through miR­200a­mediated ß-catenin pathway. Our data suggest that TSN may suppress oncogenic phenotypes of human GC cells partly via miR­200a/ß-catenin axis. Hence, TSN may have a promising chemotherapeutic activity for GC therapy.