Tumor cells hijack enteric glia to activate colon cancer stem cells and stimulate tumorigenesis.

BACKGROUND: Colon cancer stem cells (CSCs), considered responsible for tumor initiation and cancer relapse, are constantly exposed to regulatory cues emanating from neighboring cells present in the tumor microenvironment. Among these cells are enteric glial cells (EGCs) that are potent regulators of the epithelium functions in a healthy intestine. However, whether EGCs impact CSC-driven tumorigenesis remains unknown. METHODS: Impact of human EGC primary cultures or a non-transformed EGC line on CSCs isolated from human primary colon adenocarcinomas or colon cancer cell lines with different p53, MMR system and stemness status was determined using murine xenograft models and 3D co-culture systems. Supernatants of patient-matched human primary colon adenocarcinomas and non-adjacent healthy mucosa were used to mimic tumor versus healthy mucosa secretomes and compare their effects on EGCs. FINDINGS: Our data show that EGCs stimulate CSC expansion and ability to give rise to tumors via paracrine signaling. Importantly, only EGCs that were pre-activated by tumor epithelial cell-derived soluble factors increased CSC tumorigenicity. Pharmacological inhibition of PGE2 biosynthesis in EGCs or IL-1 knockdown in tumor epithelial cells prevented EGC acquisition of a pro-tumorigenic phenotype. Inhibition of PGE2 receptor EP4 and EGFR in CSCs inhibited the effects of tumor-activated EGCs. INTERPRETATION: Altogether, our results show that EGCs, once activated by the tumor, acquire a pro-tumorigenic phenotype and stimulate CSC-driven tumorigenesis via a PGE2/EP4/EGFR-dependent pathway. FUNDING: This work was supported by grants from the French National Cancer Institute, La Ligue contre le Cancer, the 'Région des Pays de la Loire' and the UNC Lineberger Comprehensive Cancer Center.

Comparative Acceptability and Perceived Clinical Utility of Monitoring Tools: A Nationwide Survey of Patients with Inflammatory Bowel Disease.

BACKGROUND: Objective control of intestinal inflammation during inflammatory bowel disease (IBD) is becoming the main driver for medical treatment. However, the monitoring tools-related burden remains poorly investigated. We aimed to evaluate their comparative acceptability and utility according to patients with IBD. METHODS: After a preliminary phase, the final questionnaire encompassing self-administered and physician questionnaires was prospectively and consecutively submitted to 916 patients with IBD from 20 public and private centers. Acceptability and utility visual analog scales (VAS) were expressed as median with interquartile range. RESULTS: Regarding the group of patients with Crohn's disease (n = 618), venipuncture (VAS = 9.3 [8.8-9.7]) and ultrasonography (VAS = 9.3 [8.7-9.7]) were the most acceptable tools (P < 0.0001, for each comparison), whereas rectosigmoidoscopy was the least acceptable tool (VAS = 4.4 [1.2-7.3]) (P < 0.0001, for each comparison). Wireless capsule endoscopy (VAS = 8.5 [5.2-9.3]), magnetic resonance enterocolonography (VAS = 8.0 [5.0-9.2]), and stools collection (VAS = 7.7 [4.6-9.3]) were more acceptable than colonoscopy (VAS = 6.7 [4.3-8.9]) (P < 0.0001, for each comparison). The acceptability was assessed in 298 patients with ulcerative colitis for venipuncture (VAS = 9.4 [8.8-9.7]), stools collection (VAS = 8.1 [5.7-9.4]), colonoscopy (VAS = 7.5 [4.7-9.2]), and rectosigmoidoscopy (VAS = 6.7 [2.8-9.1]); (P < 0.001 for each comparison). All monitoring tools were considered as highly useful by patients with IBD. Decreased acceptability was related to embarrassment for the collection/transport of stools (60.7%), bowel cleansing (76.3%) for colonoscopy, abdominal discomfort (51.3%) and rectal enema (36.6%) for rectosigmoidoscopy, bowel distension (48.3%) for magnetic resonance enterocolonography, and potential capsule retention (21.4%) for wireless capsule endoscopy. CONCLUSIONS: Among the IBD monitoring tools, endoscopy demonstrated the lowest acceptability supporting the development of alternative modalities. Patients' information and examination conditions should be improved to ensure proper monitoring adherence.

Enteric glia protect against Shigella flexneri invasion in intestinal epithelial cells: a role for S-nitrosoglutathione.

BACKGROUND: Enteric glial cells (EGCs) are important regulators of intestinal epithelial barrier (IEB) functions. EGC-derived S-nitrosoglutathione (GSNO) has been shown to regulate IEB permeability. Whether EGCs and GSNO protect the IEB during infectious insult by pathogens such as Shigella flexneri is not known. METHODS: S flexneri effects were characterised using in vitro coculture models of Caco-2 cells and EGCs (or GSNO), ex vivo human colonic mucosa, and in vivo ligated rabbit intestinal loops. The effect of EGCs on S flexneri-induced changes in the invasion area and the inflammatory response were analysed by combining immunohistochemical, ELISA and PCR methods. Expression of small G-proteins was analysed by western blot. Expression of ZO-1 and localisation of bacteria were analysed by fluorescence microscopy. RESULTS: EGCs significantly reduced barrier lesions and inflammatory response induced by S flexneri in Caco-2 monolayers. The EGC-mediated effects were reproduced by GSNO, but not by reduced glutathione, and pharmacological inhibition of pathways involved in GSNO synthesis reduced EGC protecting effects. Furthermore, expression of Cdc42 and phospho-PAK in Caco-2 monolayers was significantly reduced in the presence of EGCs or GSNO. In addition, changes in ZO-1 expression and distribution induced by S flexneri were prevented by EGCs and GSNO. Finally, GSNO reduced S flexneri-induced lesions of the IEB in human mucosal colonic explants and in a rabbit model of shigellosis. CONCLUSION: These results highlight a major protective function of EGCs and GSNO in the IEB against S flexneri attack. Consequently, this study lays the scientific basis for using GSNO to reduce barrier susceptibility to infectious or inflammatory challenge.