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Burchat N, Vidola J, Pfreundschuh S, Sharma P, Rizzolo D, Guo GL, Sampath H. Intestinal Stearoyl-CoA Desaturase-1 Regulates Energy Balance via Alterations in Bile Acid Homeostasis. Cell Mol Gastroenterol Hepatol 2024:101403. [PMID: 39278403 DOI: 10.1016/j.jcmgh.2024.101403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 09/06/2024] [Accepted: 09/09/2024] [Indexed: 09/18/2024]
Abstract
BACKGROUND & AIMS Stearoyl-CoA desaturase-1 (SCD1) converts saturated fatty acids into monounsaturated fatty acids and plays an important regulatory role in lipid metabolism. Previous studies have demonstrated that mice deficient in SCD1 are protected from diet-induced obesity and hepatic steatosis due to altered lipid assimilation and increased energy expenditure. Previous studies in our lab have shown that intestinal SCD1 modulates intestinal and plasma lipids and alters cholesterol metabolism. Here, we investigated a novel role for intestinal SCD1 in the regulation of systemic energy balance. METHODS To interrogate the role of intestinal SCD1 in modulating whole body metabolism, intestine-specific Scd1 knockout (iKO) mice were maintained on standard chow diet or challenged with a high-fat diet (HFD). Studies included analyses of bile acid content and composition, and metabolic phenotyping, including body composition, indirect calorimetry, glucose tolerance analyses, quantification of the composition of the gut microbiome, and assessment of bile acid signaling pathways. RESULTS iKO mice displayed elevated plasma and hepatic bile acid content and decreased fecal bile acid excretion, associated with increased expression of the ileal bile acid uptake transporter, Asbt. In addition, the alpha and beta diversity of the gut microbiome was reduced in iKO mice, with several alterations in microbe species being associated with the observed increases in plasma bile acids. These increases in plasma bile acids were associated with increased expression of TGR5 targets, including Dio2 in brown adipose tissue and elevated plasma glucagon-like peptide-1 levels. Upon HFD challenge, iKO mice had reduced metabolic efficiency apparent through decreased weight gain despite higher food intake. Concomitantly, energy expenditure was increased, and glucose tolerance was improved in HFD-fed iKO mice. CONCLUSION Our results indicate that deletion of intestinal SCD1 has significant impacts on bile acid homeostasis and whole-body energy balance, likely via activation of TGR5.
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Affiliation(s)
- Natalie Burchat
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey
| | - Jeanine Vidola
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey
| | - Sarah Pfreundschuh
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey
| | - Priyanka Sharma
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey
| | - Daniel Rizzolo
- Ernest Mario School of Pharmacy, Rutgers University, New Brunswick, New Jersey
| | - Grace L Guo
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey; Ernest Mario School of Pharmacy, Rutgers University, New Brunswick, New Jersey
| | - Harini Sampath
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey; Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey.
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Burchat N, Vidola J, Pfreundschuh S, Sharma P, Rizzolo D, Guo GL, Sampath H. Intestinal stearoyl-CoA desaturase-1 regulates energy balance via alterations in bile acid homeostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575400. [PMID: 38260602 PMCID: PMC10802577 DOI: 10.1101/2024.01.12.575400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Background and Aims Stearoyl-CoA desaturase-1 (SCD1) converts saturated fatty acids into monounsaturated fatty acids and plays an important regulatory role in lipid metabolism. Previous studies have demonstrated that mice deficient in SCD1 are protected from diet-induced obesity and hepatic steatosis due to altered lipid esterification and increased energy expenditure. Previous studies in our lab have shown that intestinal SCD1 modulates intestinal and plasma lipids and alters cholesterol metabolism. Here we investigated a novel role for intestinal SCD1 in the regulation of systemic energy balance. Methods To interrogate the role of intestinal SCD1 in modulating whole body metabolism, intestine-specific Scd1 knockout (iKO) mice were maintained on standard chow diet or challenged with a high-fat diet (HFD). Studies included analyses of bile acid content and composition, metabolic phenotyping including body composition, indirect calorimetry, glucose tolerance analyses, and assessment of bile acid signaling pathways. Results iKO mice displayed elevated plasma and hepatic bile acid content and decreased fecal bile acid excretion, associated with increased expression of the ileal bile acid uptake transporter, Asbt . These increases were associated with increased expression of TGR5 targets, including Dio2 in brown adipose tissue and elevated plasma glucagon-like peptide-1 levels. Upon HFD challenge, iKO mice had reduced metabolic efficiency apparent through decreased weight gain despite higher food intake. Concomitantly, energy expenditure was increased, and glucose tolerance was improved in HFD-fed iKO mice. Conclusion Our results indicate that deletion of intestinal SCD1 has significant impacts on bile acid metabolism and whole-body energy balance, likely via activation of TGR5.
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Nguyen JT, Riessen R, Zhang T, Kieffer C, Anakk S. Deletion of Intestinal SHP Impairs Short-term Response to Cholic Acid Challenge in Male Mice. Endocrinology 2021; 162:6189092. [PMID: 33769482 PMCID: PMC8256632 DOI: 10.1210/endocr/bqab063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 02/07/2023]
Abstract
Small heterodimer partner (SHP) is a crucial regulator of bile acid (BA) transport and synthesis; however, its intestine-specific role is not fully understood. Here, we report that male intestine-specific Shp knockout (IShpKO) mice exhibit higher intestinal BA but not hepatic or serum BA levels compared with the f/f Shp animals when challenged with an acute (5-day) 1% cholic acid (CA) diet. We also found that BA synthetic genes Cyp7a1 and Cyp8b1 are not repressed to the same extent in IShpKO compared with control mice post-CA challenge. Loss of intestinal SHP did not alter Fxrα messenger RNA (mRNA) but increased Asbt (BA ileal uptake transporter) and Ostα (BA ileal efflux transporter) expression even under chow-fed conditions. Surprisingly, the acute CA diet in IShpKO did not elicit the expected induction of Fgf15 but was able to maintain the suppression of Asbt, and Ostα/β mRNA levels. At the protein level, apical sodium-dependent bile acid transporter (ASBT) was downregulated, while organic solute transporter-α/β (OSTα/β) expression was induced and maintained regardless of diet. Examination of ileal histology in IShpKO mice challenged with acute CA diet revealed reduced villi length and goblet cell numbers. However, no difference in villi length, and the expression of BA regulator and transporter genes, was seen between f/f Shp and IShpKO animals after a chronic (14-day) CA diet, suggesting a potential adaptive response. We found the upregulation of the Pparα-Ugt axis after 14 days of CA diet may reduce the BA burden and compensate for the ileal SHP function. Thus, our study reveals that ileal SHP expression contributes to both overall intestinal structure and BA homeostasis.
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Affiliation(s)
- James T Nguyen
- Department of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ryan Riessen
- Department of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tongyu Zhang
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Collin Kieffer
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sayeepriyadarshini Anakk
- Department of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Correspondence:Sayeepriyadarshini Anakk, Department of Molecular & Integrative Physiology and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, 450 Medical Science Building, 506 South Matthews Avenue, Urbana, IL 61801, USA. E-mail:
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Chen HY, Hu Y, Lu NH, Zhu Y. Caudal type homeoboxes as a driving force in Helicobacter pylori infection-induced gastric intestinal metaplasia. Gut Microbes 2020; 12:1-12. [PMID: 33031021 PMCID: PMC7553748 DOI: 10.1080/19490976.2020.1809331] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
(H. pylori), a common pathogenic bacterium in the stomach, has been demonstrated to be a major cause of gastric cancer (GC). The typical pathological evolution of H. pylori infection-induced GC involves development from gastric atrophy, via intestinal metaplasia (IM) and dysplasia, to intestinal-type GC. During this process, IM is considered to be an "irreversible point" that significantly increases the risk for GC. Therefore, the elucidation of the mechanism underlying IM is of great significance for the prevention and treatment of gastric mucosal carcinogenesis associated with H. pylori infection. Caudal type homeoboxes (CDXs) are transcription factors involved in intestinal differentiation establishment and the maintenance of normal intestinal mucosa and IM. H. pylori infection increases the expression of CDXs through epigenetic regulation, the nuclear factor-kappaB signaling pathway and its downstream proinflammatory factors, and the transforming growth factor-beta signaling pathway, leading to the progression from normal gastric mucosa to IM. However, the precise mechanisms of gastric intestinal metaplasia have not yet been fully elucidated. In this review, we focus on research progress revealing the functions of CDXs in H. pylori infection-induced IM, as well as the regulators modulating this process.
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Affiliation(s)
- Hong-Yan Chen
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Yi Hu
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Nong-Hua Lu
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China
| | - Yin Zhu
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China,CONTACT Yin Zhu Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang330006, Jiangxi Province, China
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Yang N, Dong YQ, Jia GX, Fan SM, Li SZ, Yang SS, Li YB. ASBT(SLC10A2): A promising target for treatment of diseases and drug discovery. Biomed Pharmacother 2020; 132:110835. [PMID: 33035828 DOI: 10.1016/j.biopha.2020.110835] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/17/2020] [Accepted: 09/28/2020] [Indexed: 12/14/2022] Open
Abstract
Bile acids has gradually become a new focus in various diseases, and ASBT as a transporter responsible for the reabsorption of ileal bile acids, is a key hinge associated to the bile acids-cholesterol balance and bile acids of enterohepatic circulation. The cumulative studies have also shown that ASBT is a promising target for treatment of liver, gallbladder, intestinal and metabolic diseases. This article briefly reviewed the process of bile acids enterohepatic circulation, as well as the regulations of ASBT expression, covering transcription factors, nuclear receptors and gut microbiota. In addition, the relationship between ASBT and various diseases were discussed in this paper. According to the structural classification of ASBT inhibitors, the research status of ASBT inhibitors and potential ASBT inhibitors of traditional Chinese medicine (such resveratrol, jatrorrhizine in Coptis chinensis) were summarized. This review provides a basis for the development of ASBT inhibitors and the treatment strategy of related diseases.
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Affiliation(s)
- Na Yang
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Ya-Qian Dong
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Guo-Xiang Jia
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Si-Miao Fan
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Shan-Ze Li
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China
| | - Shen-Shen Yang
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China.
| | - Yu-Bo Li
- Tianjin University of Traditional Chinese Medicine, No.10, Poyang Lake Road, Tuanbo New City, Jinghai District, Tianjin 301617, China.
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Ticho AL, Malhotra P, Dudeja PK, Gill RK, Alrefai WA. Intestinal Absorption of Bile Acids in Health and Disease. Compr Physiol 2019; 10:21-56. [PMID: 31853951 PMCID: PMC7171925 DOI: 10.1002/cphy.c190007] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The intestinal reclamation of bile acids is crucial for the maintenance of their enterohepatic circulation. The majority of bile acids are actively absorbed via specific transport proteins that are highly expressed in the distal ileum. The uptake of bile acids by intestinal epithelial cells modulates the activation of cytosolic and membrane receptors such as the farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (GPBAR1), which has a profound effect on hepatic synthesis of bile acids as well as glucose and lipid metabolism. Extensive research has focused on delineating the processes of bile acid absorption and determining the contribution of dysregulated ileal signaling in the development of intestinal and hepatic disorders. For example, a decrease in the levels of the bile acid-induced ileal hormone FGF15/19 is implicated in bile acid-induced diarrhea (BAD). Conversely, the increase in bile acid absorption with subsequent overload of bile acids could be involved in the pathophysiology of liver and metabolic disorders such as fatty liver diseases and type 2 diabetes mellitus. This review article will attempt to provide a comprehensive overview of the mechanisms involved in the intestinal handling of bile acids, the pathological implications of disrupted intestinal bile acid homeostasis, and the potential therapeutic targets for the treatment of bile acid-related disorders. Published 2020. Compr Physiol 10:21-56, 2020.
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Affiliation(s)
- Alexander L. Ticho
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Pooja Malhotra
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Pradeep K. Dudeja
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
- jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Ravinder K. Gill
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Waddah A. Alrefai
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
- jesse Brown VA Medical Center, Chicago, Illinois, USA
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7
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Ferrebee CB, Li J, Haywood J, Pachura K, Robinson BS, Hinrichs BH, Jones RM, Rao A, Dawson PA. Organic Solute Transporter α-β Protects Ileal Enterocytes From Bile Acid-Induced Injury. Cell Mol Gastroenterol Hepatol 2018; 5:499-522. [PMID: 29930976 PMCID: PMC6009794 DOI: 10.1016/j.jcmgh.2018.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 01/05/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS Ileal bile acid absorption is mediated by uptake via the apical sodium-dependent bile acid transporter (ASBT), and export via the basolateral heteromeric organic solute transporter α-β (OSTα-OSTβ). In this study, we investigated the cytotoxic effects of enterocyte bile acid stasis in Ostα-/- mice, including the temporal relationship between intestinal injury and initiation of the enterohepatic circulation of bile acids. METHODS Ileal tissue morphometry, histology, markers of cell proliferation, gene, and protein expression were analyzed in male and female wild-type and Ostα-/- mice at postnatal days 5, 10, 15, 20, and 30. Ostα-/-Asbt-/- mice were generated and analyzed. Bile acid activation of intestinal Nrf2-activated pathways was investigated in Drosophila. RESULTS As early as day 5, Ostα-/- mice showed significantly increased ileal weight per length, decreased villus height, and increased epithelial cell proliferation. This correlated with premature expression of the Asbt and induction of bile acid-activated farnesoid X receptor target genes in neonatal Ostα-/- mice. Expression of reduced nicotinamide adenine dinucleotide phosphate oxidase-1 and Nrf2-anti-oxidant responsive genes were increased significantly in neonatal Ostα-/- mice at these postnatal time points. Bile acids also activated Nrf2 in Drosophila enterocytes and enterocyte-specific knockdown of Nrf2 increased sensitivity of flies to bile acid-induced toxicity. Inactivation of the Asbt prevented the changes in ileal morphology and induction of anti-oxidant response genes in Ostα-/- mice. CONCLUSIONS Early in postnatal development, loss of Ostα leads to bile acid accumulation, oxidative stress, and a restitution response in ileum. In addition to its essential role in maintaining bile acid homeostasis, Ostα-Ostβ functions to protect the ileal epithelium against bile acid-induced injury. NCBI Gene Expression Omnibus: GSE99579.
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Key Words
- ARE, anti-oxidant response element
- Asbt, apical sodium-dependent bile acid transporter
- CDCA, chenodeoxycholic acid
- Drosophila
- FGF, fibroblast growth factor
- FXR, farnesoid X receptor
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescence protein
- GSH, reduced glutathione
- GSSG, oxidized glutathione
- Ibabp, ileal bile acid binding protein
- Ileum
- NEC, necrotizing enterocolitis
- Neonate
- Nox, reduced nicotinamide adenine dinucleotide phosphate oxidase
- Nrf2, nuclear factor (erythroid-derived 2)-like 2
- Nuclear Factor Erythroid-Derived 2-Like 2
- Ost, organic solute transporter
- PBS, phosphate-buffered saline
- ROS, reactive oxygen species
- Reactive Oxygen Species
- TNF, tumor necrosis factor
- TUNEL, terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling
- WT, wild type
- cRNA, complementary RNA
- mRNA, messenger RNA
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Affiliation(s)
- Courtney B. Ferrebee
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jianing Li
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Jamie Haywood
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Kimberly Pachura
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | | | | | - Rheinallt M. Jones
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Anuradha Rao
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Paul A. Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
- Children’s Healthcare of Atlanta, Atlanta, Georgia
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Chatterjee I, Kumar A, Castilla-Madrigal RM, Pellon-Cardenas O, Gill RK, Alrefai WA, Borthakur A, Verzi M, Dudeja PK. CDX2 upregulates SLC26A3 gene expression in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2017; 313:G256-G264. [PMID: 28572085 PMCID: PMC5625132 DOI: 10.1152/ajpgi.00108.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/26/2017] [Accepted: 05/26/2017] [Indexed: 01/31/2023]
Abstract
SLC26A3 [downregulated in adenoma (DRA)] plays a key role in mammalian intestinal NaCl absorption, in that it mediates apical membrane Cl-/[Formula: see text] exchange. DRA function and expression are significantly decreased in diarrhea associated with inflammatory bowel disease. DRA is also considered to be a marker of cellular differentiation and is predominantly expressed in differentiated epithelial cells. Caudal-type homeobox protein-2 (CDX2) is known to regulate genes involved in intestinal epithelial differentiation and proliferation. Reduced expression of both DRA and CDX2 in intestinal inflammation prompted us to study whether the DRA gene is directly regulated by CDX2. Our initial studies utilizing CDX2 knockout (CDX2fV/fV;Cre+) mice showed a marked reduction in DRA mRNA and protein levels in proximal and distal colon. In silico analysis of the DRA promoter showed two consensus sites for CDX2 binding. Therefore, we utilized Caco-2 cells as an in vitro model to examine if DRA is a direct target of CDX2 regulation. siRNA-mediated silencing of CDX2 in Caco-2 cells resulted in a marked (~50%) decrease in DRA mRNA and protein levels, whereas ectopic overexpression of CDX2 upregulated DRA expression and also stimulated DRA promoter activity, suggesting transcriptional regulation. Electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrated direct binding of CDX2 to one of the two putative CDX2 binding sites in the DRA promoter (+645/+663). In summary, our studies, for the first time, demonstrate transcriptional regulation of DRA expression by CDX2, implying that reduced expression of DRA in inflammatory bowel disease-associated diarrhea may, in part, be due to downregulation of CDX2 in the inflamed mucosa.NEW & NOTEWORTHY SLC26A3 [downregulated in adenoma (DRA)] mediates intestinal luminal NaCl absorption and is downregulated in inflammatory bowel disease-associated diarrhea. Since both DRA and caudal-type homeobox protein-2 (CDX2) are reduced in intestinal inflammation and the DRA promoter harbors CDX2 binding sites, we examined whether the DRA gene is regulated by CDX2. Our studies, for the first time, demonstrate transcriptional regulation of DRA expression by CDX2 via direct binding to the DRA promoter, suggesting that reduced expression of DRA in inflammatory bowel disease-associated diarrhea could, in part, be attributed to downregulation of CDX2.
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Affiliation(s)
- Ishita Chatterjee
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Anoop Kumar
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | | | | | - Ravinder K. Gill
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Waddah A. Alrefai
- 1Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Alip Borthakur
- 2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Michael Verzi
- 4Department of Genetics, Rutgers University, Piscataway, New Jersey
| | - Pradeep K. Dudeja
- 1Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; ,2Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois;
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Fangning W, Chunguang M, Hailiang Z, Guohai S, Yao Z, Bo D, Yijun S, Yiping Z, Dingwei Y. Identification and validation of soluble carrier family expression signature for predicting poor outcome of renal cell carcinoma. J Cancer 2017; 8:2010-2017. [PMID: 28819401 PMCID: PMC5559962 DOI: 10.7150/jca.18257] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/30/2017] [Indexed: 01/04/2023] Open
Abstract
The soluble carrier (SLC) family plays an important role in cell metabolism. The purpose of the current study was to screen SLCs as potential prognostic factors in clear cell renal cell carcinoma (ccRCC). A total of 509 patients with ccRCC from The Cancer Genome Atlas (TCGA) cohort were enrolled in this study. The expression profile of SLCs was obtained from the TCGA RNAseq database. Metadata of the TCGA cohort, including age, sex, TNM stage, tumor grade, American Joint Committee on Cancer stage, laterality, and overall survival, were collected. Univariate and multivariate Cox proportional hazards regression models were used to analyze the relative factors. Prognosis-associated genes were further validated in a Fudan University Shanghai Cancer Center (FUSCC) cohort consisting of 178 patients. Among a total of 364 SLC transporters, 61 were independent predictors of ccRCC patient overall survival. Among the 61 SLC transporters, 26 were significantly downregulated and 23 were significantly upregulated in tumor tissues compared with non-malignant kidney tissues. Analyses of two open source, RNA expression data sets on sunitinib response revealed that SLC10A2 was downregulated in tyrosine kinase inhibitor-resistant samples. We validated SLC10A2 expression in the FUSCC cohort and showed that SLC10A2 expression was an independent prognostic predictor of overall survival of ccRCC (hazard ratio=0.432, 95% CI: 0.204-0.915). Our results identified a number of associations of SLC gene expression with prognosis of ccRCC patients, indicating that these genes may represent possible oncogenes that could serve as therapeutic targets of ccRCC.
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Affiliation(s)
- Wan Fangning
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Ma Chunguang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Zhang Hailiang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Shi Guohai
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Zhu Yao
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Dai Bo
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Shen Yijun
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Zhu Yiping
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Ye Dingwei
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032 People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
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Hepatocyte nuclear factor 1 coordinates multiple processes in a model of intestinal epithelial cell function. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:591-8. [PMID: 26855178 DOI: 10.1016/j.bbagrm.2016.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 02/01/2016] [Accepted: 02/04/2016] [Indexed: 12/26/2022]
Abstract
Mutations in hepatocyte nuclear factor 1 transcription factors (HNF1α/β) are associated with diabetes. These factors are well studied in the liver, pancreas and kidney, where they direct tissue-specific gene regulation. However, they also have an important role in the biology of many other tissues, including the intestine. We investigated the transcriptional network governed by HNF1 in an intestinal epithelial cell line (Caco2). We used chromatin immunoprecipitation followed by direct sequencing (ChIP-seq) to identify HNF1 binding sites genome-wide. Direct targets of HNF1 were validated using conventional ChIP assays and confirmed by siRNA-mediated depletion of HNF1, followed by RT-qPCR. Gene ontology process enrichment analysis of the HNF1 targets identified multiple processes with a role in intestinal epithelial cell function, including properties of the cell membrane, cellular response to hormones, and regulation of biosynthetic processes. Approximately 50% of HNF1 binding sites were also occupied by other members of the intestinal transcriptional network, including hepatocyte nuclear factor 4A (HNF4A), caudal type homeobox 2 (CDX2), and forkhead box A2 (FOXA2). Depletion of HNF1 in Caco2 cells increases FOXA2 abundance and decreases levels of CDX2, illustrating the coordinated activities of the network. These data suggest that HNF1 plays an important role in regulating intestinal epithelial cell function, both directly and through interactions with other intestinal transcription factors.
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Zheng Y, Benet LZ, Okochi H, Chen X. pH Dependent but not P-gp Dependent Bidirectional Transport Study of S-propranolol: The Importance of Passive Diffusion. Pharm Res 2015; 32:2516-26. [PMID: 25690341 DOI: 10.1007/s11095-015-1640-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/26/2015] [Indexed: 01/06/2023]
Abstract
PURPOSE Recent controversial publications, citing studies purporting to show that P-gp mediates the transport of propranolol, proposed that passive biological membrane transport is negligible. Based on the BDDCS, the extensively metabolized-highly permeable-highly soluble BDDCS class 1 drug, propranolol, shows a high passive permeability at concentrations unrestricted by solubility that can overwhelm any potential transporter effects. Here we reinvestigate the effects of passive diffusion and carrier-mediated transport on S-propranolol. METHODS Bidirectional permeability and inhibition of efflux transport studies were carried out in MDCK, MDCK-MDR1 and Caco-2 cell lines at different concentrations. Transcellular permeability studies were conducted at different apical pHs in the rat jejunum Ussing chamber model and PAMPA system. RESULTS S-propranolol exhibited efflux ratios lower than 1 in MDCK, MDCK-MDR1 and Caco-2 cells. No significant differences of Papp, B->A in the presence and absence of the efflux inhibitor GG918 were observed. However, an efflux ratio of 3.63 was found at apical pH 6.5 with significant decrease in Papp, A->B and increase in Papp, B->A compared to apical pH 7.4 in Caco-2 cell lines. The pH dependent permeability was confirmed in the Ussing chamber model. S-propranolol flux was unchanged during inhibition by verapamil and rifampin. Furthermore, pH dependent permeability was also observed in the PAMPA system. CONCLUSIONS S-propranolol does not exhibit active transport as proposed previously. The "false" positive efflux ratio can be explained by the pH partition theory. As expected, passive diffusion, but not active transport, plays the primary role in the permeability of the BDDCS class 1 drug propranolol.
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Affiliation(s)
- Yi Zheng
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, #24 Tongjiaxiang, Mailbox 210, Nanjing, 210009, Jiangsu, China
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Freund JN, Duluc I, Reimund JM, Gross I, Domon-Dell C. Extending the functions of the homeotic transcription factor Cdx2 in the digestive system through nontranscriptional activities. World J Gastroenterol 2015; 21:1436-1443. [PMID: 25663763 PMCID: PMC4316086 DOI: 10.3748/wjg.v21.i5.1436] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/25/2014] [Accepted: 12/16/2014] [Indexed: 02/06/2023] Open
Abstract
The homeoprotein encoded by the intestinal-specific Cdx2 gene is a major regulator of gut development and homeostasis, also involved in colon cancer as well as in intestinal-type metaplasias when it is abnormally expressed outside the gut. At the molecular level, structure/function studies have demonstrated that the Cdx2 protein is a transcription factor containing a conserved homeotic DNA-binding domain made of three alpha helixes arranged in a helix-turn-helix motif, preceded by a transcriptional domain and followed by a regulatory domain. The protein interacts with several thousand sites on the chromatin and widely regulates intestinal functions in stem/progenitor cells as well as in mature differentiated cells. Yet, this transcription factor also acts trough original nontranscriptional mechanisms. Indeed, the identification of novel protein partners of Cdx2 and also of a splicing variant revealed unexpected functions in the control of signaling pathways like the Wnt and NF-κB pathways, in double-strand break DNA repair and in premessenger RNA splicing. These novel functions of Cdx2 must be considered to fully understand the complexity of the role of Cdx2 in the healthy intestine and in diseases.
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Alsalahi O, Dobrian AD. Proton Pump Inhibitors: The Culprit for Barrett's Esophagus? Front Oncol 2015; 4:373. [PMID: 25621278 PMCID: PMC4288325 DOI: 10.3389/fonc.2014.00373] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/12/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Omran Alsalahi
- Department of Physiological Sciences, Eastern Virginia Medical School , Norfolk, VA , USA
| | - Anca D Dobrian
- Department of Physiological Sciences, Eastern Virginia Medical School , Norfolk, VA , USA
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Ramzan Z, Nassri AB, Huerta S. The use of imaging and biomarkers in diagnosing Barrett's esophagus and predicting the risk of neoplastic progression. Expert Rev Mol Diagn 2014; 14:575-91. [PMID: 24831686 DOI: 10.1586/14737159.2014.919856] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Long-standing gastroesophageal reflux disease can result in transformation of the normal squamous lining of the esophagus into columnar epithelium (with goblet cells). This condition, Barrett's esophagus (BE), is considered a risk factor for esophageal cancer (EAC) and may be the cause of the increased incidence of EAC over the last few decades. Currently, endoscopy with biopsies revealing dysplasia is the best predictor for neoplastic progression in patients with BE. However, the use of more sophisticated imaging techniques and biomarkers with or without histological assessment may be helpful in more accurate prediction of malignant transformation in these patients. New approaches to the evaluation of BE such as epigenetics, miRNA analysis, detection of DNA content abnormalities and loss of heterozygosity have great potential to shed light on the complex gastroesophageal reflux disease -BE-EAC sequence.
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Affiliation(s)
- Zeeshan Ramzan
- VA North Texas Healthcare System - Dallas VA Medical Center, University of Texas Southwestern Medical Center, 4500 S. Lancaster Road, Dallas, TX 75216, USA
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Yan LH, Wei WY, Xie YB, Xiao Q. New insights into the functions and localization of the homeotic gene CDX2 in gastric cancer. World J Gastroenterol 2014; 20:3960-3966. [PMID: 24744585 PMCID: PMC3983451 DOI: 10.3748/wjg.v20.i14.3960] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/22/2013] [Accepted: 02/20/2014] [Indexed: 02/06/2023] Open
Abstract
Gastric cancer is one of the most frequent cancers, and it ranks the third most common cancer in China. The most recently caudal-related homeobox transcription factor 2 (CDX2) is expressed in a large number of human gastrointestinal cancers. In addition, gastric epithelial cell mutations in CDX2 result in tumor promotion, which is characterized by cellular drug resistance and a high proclivity for developing cancer. A series of publications over the past years suggests a mechanism by which CDX2 overexpression results in multidrug resistance. CDX2 appears to forward control regenerating IV and the multidrug resistance 1 expression signaling pathway for regulation of cell drug resistance.
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Ghosh A, Chen F, Banerjee S, Xu M, Shneider BL. c-Fos mediates repression of the apical sodium-dependent bile acid transporter by fibroblast growth factor-19 in mice. Am J Physiol Gastrointest Liver Physiol 2014; 306:G163-71. [PMID: 24309182 PMCID: PMC3920077 DOI: 10.1152/ajpgi.00276.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fibroblast growth factor-19 (FGF-19), a bile acid-responsive enterokine, is secreted by the ileum and regulates a variety of metabolic processes. These studies examined the signal transduction pathways operant in FGF-19-mediated repression of the apical sodium-dependent bile acid transporter (ASBT). Responses to FGF-19 were assessed in Caco-2 and CT-26 cells and in mice where c-fos was conditionally silenced in the intestine by a cre-lox strategy. FGF-19 treatment of Caco-2 cells or wild-type mice led to a significant reduction in ASBT protein expression and enhanced phosphorylation of extracellular signaling kinase 1/2 (ERK1/2), c-Fos, and c-Jun. FGF-19 treatment of Caco-2 cells led to a reduction in activity of the human ASBT promoter and this repression could be blocked by treatment with a mitogen-activated protein kinase/ERK kinase (MEK1/2) inhibitor or by silencing jun kinase 1, jun kinase 2, c-fos, or c-jun. Site directed mutagenesis of a c-fos binding element in the ASBT promoter blocked FGF-19-mediated repression in luciferase reporter constructs. ASBT promoter activity was repressed by FGF-19 in CT-26 cells and this repression could be reduced by MEK1/2 inhibition or silencing c-fos. FGF-19-mediated repression of ASBT protein expression was abrogated in mice where c-fos was conditionally silenced in the intestine. In contrast, ASBT was repressed in the c-Fos expressing gallbladders of the same mice. The studies demonstrate that FGF-19 represses the expression of ASBT in the ileum and gallbladder via a signal transduction pathway involving MEK1/2, ERK1/2, JNK1, JNK2, and c-Fos.
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Affiliation(s)
- Ayantika Ghosh
- Children's Hospital of Pittsburgh of UPMC, Division of Pediatric Gastroenterology, Hepatology and Nutrition, 4401 Penn Ave., Pittsburgh, PA 15224.
| | - Frank Chen
- 1Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Swati Banerjee
- 1Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
| | - Ming Xu
- 2Department of Anesthesia and Critical Care, University of Chicago School of Medicine, Chicago, Illinois
| | - Benjamin L. Shneider
- 1Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and
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The solute carrier family 10 (SLC10): beyond bile acid transport. Mol Aspects Med 2013; 34:252-69. [PMID: 23506869 DOI: 10.1016/j.mam.2012.07.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/13/2012] [Indexed: 12/22/2022]
Abstract
The solute carrier (SLC) family 10 (SLC10) comprises influx transporters of bile acids, steroidal hormones, various drugs, and several other substrates. Because the seminal transporters of this family, namely, sodium/taurocholate cotransporting polypeptide (NTCP; SLC10A1) and the apical sodium-dependent bile acid transporter (ASBT; SLC10A2), were primarily bile acid transporters, the term "sodium bile salt cotransporting family" was used for the SLC10 family. However, this notion became obsolete with the finding of other SLC10 members that do not transport bile acids. For example, the sodium-dependent organic anion transporter (SOAT; SLC10A6) transports primarily sulfated steroids. Moreover, NTCP was shown to also transport steroids and xenobiotics, including HMG-CoA inhibitors (statins). The SLC10 family contains four additional members, namely, P3 (SLC10A3; SLC10A3), P4 (SLC10A4; SLC10A4), P5 (SLC10A5; SLC10A5) and SLC10A7 (SLC10A7), several of which were unknown or considered hypothetical until approximately a decade ago. While their substrate specificity remains undetermined, great progress has been made towards their characterization in recent years. Explicitly, SLC10A4 may participate in vesicular storage or exocytosis of neurotransmitters or mastocyte mediators, whereas SLC10A5 and SLC10A7 may be involved in solute transport and SLC10A3 may have a role as a housekeeping protein. Finally, the newly found role of bile acids in glucose and energy homeostasis, via the TGR5 receptor, sheds new light on the clinical relevance of ASBT and NTCP. The present mini-review provides a brief summary of recent progress on members of the SLC10 family.
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Yan LH, Wang XT, Yang J, Lian C, Kong FB, Wei WY, Luo W, Xiao Q, Xie YB. Reversal of multidrug resistance in gastric cancer cells by CDX2 downregulation. World J Gastroenterol 2013; 19:4155-4165. [PMID: 23864778 PMCID: PMC3710417 DOI: 10.3748/wjg.v19.i26.4155] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/06/2013] [Accepted: 06/04/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the role of CDX2 in the multi-drug resistance (MDR) process of gastric cancer in vitro and in vivo.
METHODS: A cisplatin-resistant gastric cancer cell line with stable downregulation of CDX2 was established. mRNA and protein expression levels of CDX2, survivin, cyclin D1, and c-Myc were detected by western blotting and semi-quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The influence of downregulation of CDX2 on MDR was assessed by measuring IC50 of SGC7901/DDP cells to cisplatin, doxorubicin, and 5-fluorouracil, rate of doxorubicin efflux, apoptosis, and cell cycle progression detected by flow cytometry. In addition, we determined the in vivo effects of CDX2 small interfering RNA (siRNA) on tumor size, and apoptotic cells in tumor tissues were detected by deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and hematoxylin and eosin staining.
RESULTS: CDX2 siRNA led to downregulation of endogenous CDX2 mRNA (0.31 ± 0.05 vs 1.10 ± 0.51, 0.31 ± 0.05 vs 1.05 ± 0.21, P = 0.003) and protein (0.12 ± 0.08 vs 0.51 ± 0.07, 0.12 ± 0.08 vs 0.55 ± 0.16, P = 2.57 × 10-4) expression. It significantly promoted the sensitivity of SGC7901/DDP cells to cisplatin (0.12 ± 0.05 vs 0.33 ± 0.08, 0.12 ± 0.05 vs 0.39 ± 0.15, P = 0.001), doxorubicin (0.52 ± 0.13 vs 4.11 ± 1.25, 0.52 ± 0.13 vs 4.05 ± 1.44, P = 2.81 × 10-4), and 5-fluorouracil (0.82 ± 0.13 vs 2.81 ± 0.51, 0.82 ± 0.13 vs 3.28 ± 1.03, P = 1.71 × 10-4). Flow cytometry confirmed that the percentage of apoptotic cells increased after CDX2 downregulation (32.15% ± 2.15% vs 17.63% ± 3.16%, 32.15% ± 2.15% vs 19.3% ± 2.25%, P = 1.73 × 10-6). This notion was further supported by the observation that downregulation of CDX2 blocked entry into the S-phase of the cell cycle (31.53% ± 3.78% vs 65.05% ± 7.25%, 31.53% ± 3.78% vs 62.27% ± 5.02%, P = 7.55 × 10-7). Furthermore, downregulation of CDX2 significantly increased intracellular accumulation of doxorubicin (0.21 ± 0.06 vs 0.41 ± 0.11, 0.21 ± 0.06 vs 0.40 ± 0.08, P = 0.003). In molecular studies, semiquantitative RT-PCR and western blotting revealed that CDX2 downregulation could inhibit expression of c-Myc, survivin and cyclin D1.
CONCLUSION: CDX2 may be involved in regulating multiple signaling pathways in reversing MDR, suggesting that CDX2 may represent a novel target for gastric cancer therapy.
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Zhao J, Gregersen H. Relationships of CDXs and apical sodium-dependent bile acid transporter in Barrett’s esophagus. World J Gastroenterol 2013; 19:2736-2739. [PMID: 23687410 PMCID: PMC3653147 DOI: 10.3748/wjg.v19.i18.2736] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/03/2013] [Accepted: 05/08/2013] [Indexed: 02/06/2023] Open
Abstract
Barrett’s esophagus (BE) is characterized by intestinal metaplasia with the differentiated epithelium replaced by another type of epithelium morphologically similar to normal intestinal epithelium. The metaplasia is preceded by bile and acid reflux into the esophagus. BE is a premalignant condition associated with increased risk of esophageal cancer, especially esophageal adenocarcinoma. The Caudal-related homeodomain transcription factors Caudal-related homeodomain transcription factor CDX1 and CDX2 are expressed exclusively in the small and large intestine, playing important roles in proliferation and differentiation of intestinal epithelial cells. Ectopic expression of CDX1 and CDX2 occurs in BE. The apical sodium-dependent bile acid transporter (ASBT) is expressed primarily in terminal ileum where it is a key factor for intestinal reabsorption of bile salts. In addition to upregulation of CDX1 and CDX2, ASBT expression is up-regulated in BE. Furthermore, both CDX1/CDX2 and ASBT expressions are down-regulated in high-grade esophageal dysplasia. The alteration of the above-mentioned factors calls for attention: what is the relationship between CDXs and ASBT aberrant expression in BE? In this commentary, we discuss this issue on basis of the recent study done by Ma et al.
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Grainger S, Hryniuk A, Lohnes D. Cdx1 and Cdx2 exhibit transcriptional specificity in the intestine. PLoS One 2013; 8:e54757. [PMID: 23382958 PMCID: PMC3559873 DOI: 10.1371/journal.pone.0054757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/18/2012] [Indexed: 12/16/2022] Open
Abstract
The caudal-related homeodomain transcription factors Cdx1 and Cdx2 are expressed in the developing endoderm with expression persisting into adulthood. Cdx1−/− mutants are viable and fertile and display no overt intestinal phenotype. Cdx2 null mutants are peri-implantation lethal; however, conditional mutation approaches have revealed that Cdx2 is required for patterning the intestinal epithelium and specification of the colon. Cdx2 is also necessary for homeostasis of the intestinal tract in the adult, where Cdx1 and Cdx2 appear to functionally overlap in the distal colon, but not during intestinal development. Cdx1 and Cdx2 exhibit complete overlap of expression in the intestine, although they differ in their relative levels, with Cdx1 maximal in the distal colon and Cdx2 peaking in the proximal cecum. Moreover, Cdx1 protein is graded along the crypt-villus axis, being abundant in the crypts and diminishing towards the villi. Cdx2 is expressed uniformly along this axis, but is differentially phosphorylated; the functional relevance of these expression domains and phosphorylation is currently unknown. Cdx1 and Cdx2 have been suggested to exhibit functional specificity in the intestinal tract. In the present study, using cell-based models, we found that relative to Cdx1, Cdx2 was significantly less potent at effecting a transcriptional response from the Cdx1 promoter, a known Cdx target gene. We subsequently assessed this relationship in vivo using a “gene swap” approach and found that Cdx2 cannot substitute for Cdx1 in this autoregulatory loop. This is in marked contrast with the ability of Cdx2 to support Cdx1 expression and function in paraxial mesoderm and vertebral patterning, thus providing novel in vivo evidence of context-dependent transcriptional specificity between these transcription factors.
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Affiliation(s)
- Stephanie Grainger
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Alexa Hryniuk
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - David Lohnes
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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