Dataset Information

Post-transcriptional Gene Regulation in Colitis Associated Cancer.

ABSTRACT: Colitis-associated cancer (CAC) has been linked to microRNA (miRNA) aberrant expression elicited by inflammation. In this study, we used the AOM/DSS-induced CAC mice model to explore the ectopic expression of miRNAs in the precancerous stage of CAC. As a result, we found that miR-31-5p, miR-223-3p, and let-7f-5p were dysregulated during the development of intestinal dysplasia. Subsequently, we first identified the role of these three miRNAs in CAC. Adenomatous polyposis coli (APC) was revealed as a new target of miR-223-3p, and solute carrier family 9- subfamily A-member 9 (SLC9A9) and APC membrane recruitment protein 3 (AMER3) were suggested as two new targets for let-7f-5p. For miR-31-5p, we proved that it can target LATS2 mRNA so as to modulate Hippo pathway in Caco2 cells. Second, to examine if targeting these three miRNAs would lead to CAC prevention, pedunculoside, a natural triterpene glycoside capable of rescuing the down-regulation of LATS2 and APC caused by either miR-31-5p or miR-223-3p overexpression, respectively, was used in the in vivo AOM/DSS-induced CAC model. The results showed that pedunculoside (25 mg/kg) substantially mitigated the damage to mice intestine caused by DSS/AOM. These results suggested that miRNAs-elicited post-transcriptional regulation is involved in the pathogenesis of CAC, and CAC can be prevented through targeting key miRNAs that are ectopically expressed in CAC.

SUBMITTER: Chen G

PROVIDER: S-EPMC6593052 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Post-transcriptional Gene Regulation in Colitis Associated Cancer.

Chen Gang G Feng Yuan Y Li Xuezheng X Jiang Zhe Z Bei Bei B Zhang Lin L Han Yueqing Y Li Yanwu Y Li Ning N

Frontiers in genetics 20190619

Colitis-associated cancer (CAC) has been linked to microRNA (miRNA) aberrant expression elicited by inflammation. In this study, we used the AOM/DSS-induced CAC mice model to explore the ectopic expression of miRNAs in the precancerous stage of CAC. As a result, we found that miR-31-5p, miR-223-3p, and let-7f-5p were dysregulated during the development of intestinal dysplasia. Subsequently, we first identified the role of these three miRNAs in CAC. Adenomatous polyposis coli (APC) was revealed a ...[more]

PMID: 31275360

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Project description:Aim: RNA binding proteins (RBPs) are emerging as critical regulators of gut homeostasis via post-transcriptional control of key growth and repair pathways. IMP1 (IGF2 mRNA Binding Protein 1) is ubiquitously expressed during embryonic development and Imp1 hypomorphic mice exhibit severe gut growth defects. In the present study, we investigated the mechanistic contribution of intestinal epithelial IMP1 to gut homeostasis and response to injury. Method: We evaluated IMP1 expression in patients with Crohn’s disease followed by unbiased ribosome profiling in IMP1 knockout cells. Concurrently, we measured differences in histology and cytokine expression in mice with intestinal epithelial-specific Imp1 deletion (Imp1ΔIEC) following dextran sodium sulfate (DSS)- colitis. Based on ribosome profiling analysis, we evaluated changes in autophagy in Imp1ΔIEC mice as well as in silico and in vitro approaches to evaluate direct protein:RNA interactions. Finally, we analyzed the consequence of genetic deletion of Atg7 in Imp1ΔIEC mice using colitis and irradiation models. Results: IMP1 was robustly upregulated in Crohn’s disease patients and Imp1 loss lessened DSS-colitis severity. Unbiased ribosome-profiling revealed that IMP1 may coordinate translation of multiple pathways important for intestinal homeostasis, including cell cycle and autophagy, which we verified by Western blotting. Mechanistically, we observed evidence for increased autophagy flux in Imp1ΔIEC mice, reinforced through in silico and biochemical analyses revealing direct binding of IMP1 to autophagy transcripts. Finally, we found genetic deletion of Atg7 reversed the phenotype observed in DSS- or irradiation-challenged Imp1ΔIEC mice. Conclusions: IMP1 acts as a post-transcriptional regulator of gut epithelial repair, in part through modulation of autophagy. This study highlights the need for examining post-transcriptional regulation as a critical mechanism in inflammatory bowel disease.

Project description:Brahma-related gene 1 (BRG1), an ATPase subunit of the SWItch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex controls multipotent neural crest formation by regulating epithelial-mesenchymal transition (EMT)-related genes with adenosine triphosphate-dependent chromodomain-helicase DNA-binding protein 7 (CHD7). The expression of BRG1 engages in pre-mRNA splicing through interacting RNPs in cancers; however, the detailed molecular pathology of how BRG1and CHD7 relate to cancer development remains largely unveiled. This study demonstrated novel post-transcriptional regulation of BRG1 in EMT and relationship with FIRΔexon2, which is a splicing variant of the far-upstream element-binding protein (FUBP) 1-interacting repressor (FIR) lacking exon 2, which fails to repress c-myc transcription in cancers. Previously, we have reported that FIR complete knockout mice (FIR-/-) was embryonic lethal before E9.5, suggesting FIR is crucial for development. FIRΔexon2 acetylated H3K27 on promoter of BRG1 by CHIP-sequence and suppressed BRG1 expression post-transcriptionally; herein BRG1 suppressed Snai1 that is a transcriptional suppressor of E-cadherin that prevents cancer invasion and metastasis. Ribosomal proteins, hnRNPs, splicing-related factors, poly (A) binding proteins, mRNA-binding proteins, tRNA, DEAD box, and WD-repeat proteins were identified as co-immunoprecipitated proteins with FIR and FIRΔexon2 by redoing exhaustive mass spectrometry analysis. Furthermore, the effect of FIRΔexon2 on FGF8 mRNA splicing was examined as an indicator of neural development due to impaired CHD7 revealed in CHARGE syndrome. Expectedly, siRNA of FIRΔexon2 altered FGF8 pre-mRNA splicing, indicated close molecular interaction among FIRΔexon2, BRG1 and CHD7. FIRΔexon2 mRNA was elevated in human gastric cancers but not in non-invasive gastric tumors in FIR+/ mice (K19-Wnt1/C2mE x FIR+/-). The levels of FIR family (FIR, FIRΔexon2 and PUF60), BRG1, Snai1, FBW7, E-cadherin, c-Myc, cyclin-E, and SAP155 increased in the gastric tumors in FIR+/- mice compared to those expressed in wild-type mice. FIR family, Snai1, cyclin-E, BRG1, and c-Myc showed trends toward higher expression in larger tumors than in smaller tumors in Gan-mice (K19-Wnt1/C2mE). The expressions of BRG1 and Snai1 were positively correlated in the gastric tumors of the Gan-mice. Finally, BRG1 is a candidate substrate of F-box and WD-repeat domain-containing 7 (FBW7) revealed by three-dimensional crystal structure analysis that the U2AF-homology motif (UHM) of FIRΔexon2 interacted with tryptophan-425 and asparate-399 (WD)-like motif in the degron pocket of FBW7 as a UHM-ligand motif. Together, FIRΔexon2 engages in multi-step post-transcriptional regulation of BRG1, affecting EMT through the BRG1/Snai1/E-cadherin pathway and promoting tumor proliferation and invasion of gastric cancers.

Dataset Information

Post-transcriptional Gene Regulation in Colitis Associated Cancer.

Publications

Post-transcriptional Gene Regulation in Colitis Associated Cancer.

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