Expression of the REG IV gene in ulcerative colitis

Elevated Risk of Adverse Prognosis in Patients with T2-3 Stage Breast Cancer Exhibiting Non-Pathological Complete Response Following Neoadjuvant Chemotherapy: Significance of Regenerating Islet-Derived Family Member 4

Objective

In this study, we aimed to establish the role of regenerating islet-derived family member 4 (Reg IV) as an independent risk factor and prognostic predictor in patients with T2-3 stage breast cancer who exhibit a non-pathological complete response (non-pCR) following neoadjuvant chemotherapy (NACT). Additionally, we examined the potential correlation and interaction between Reg IV and epidermal growth factor receptor (EGFR).

Methods

A total of 67 patients with T2-3 stage breast cancer exhibiting non-pCR after NACT between September 2019 and December 2021 were included in this study. The analysis involved Kaplan-Meier survival comparisons, pooled hazard ratios for risk quantification, Cox regression analysis to isolate the impact of Reg IV on prognosis, Riskplots for visualizing risk profiles, and SHAP analysis to assess the importance of variables in predicting outcomes.

Results

The findings indicate that patients positive for Reg IV had a significantly poorer prognosis (HR: 2.62, 95% CI: 1.06-6.47). Co-expression of Reg IV and EGFR was associated with the worst outcomes compared to patients negative for both markers. Cox regression analysis confirmed the independent prognostic impact of Reg IV (HR: 2.63, 95% CI: 1.66-3.59). Riskplot analysis showed that patients positive for both Reg IV and EGFR predominantly experienced disease progression. SHAP analysis further reinforced the significant effect of Reg IV on the disease course, without substantial interaction with EGFR.

Conclusion

Reg IV may serve as an independent risk factor and predictive marker for adverse outcomes in patients with T2-3 stage breast cancer who do not achieve non-pCR following NACT.

Potential carcinogenic role of Reg IV in ulcerative colitis-associated colorectal neoplasia

Background

Early detection of ulcerative colitis-associated neoplasia (UC-N) remains a clinical challenge. Identification of molecular biomarkers for colorectal dysplasia and cancer may be extremely beneficial in early detection and managing cancer risk in long-standing ulcerative colitis (UC) patients.

Objective

The aim of this work is to investigate the role of Reg IV in comparison to P53 and KRAS in UC-associated dysplasia and colorectal cancer (CRC) in order to evaluate the potential use of Reg IV for dysplasia and cancer screening in UC patients.

Methods

The study was conducted on 5 groups each 20 colonic endoscopic samples: 1) Normal colonic mucosa, 2) Active UC without dysplasia/carcinoma, 3) UC-associated dysplasia, 4) UC-associated CRC (UC-CRC), 5) Sporadic CRC. All included cases were subjected to Reg IV mRNA expression analysis by quantitative reverse transcription polymerase chain reaction, and immunostaining for Reg IV, P53 and KRAS.

Results

Reg IV mRNA expression levels were found to be significantly higher in groups 3 and 4 (mean: 3.37 and 5.70, respectively). Reg IV immunostaining was highly expressed in groups 3 and 4 (mean: 45.80 and 62.35, respectively). While P53 and KRAS immunostaining was highly expressed in group 5 (mean: 64.57 and 62.90). Furthermore, Reg IV immunoexpression had shown a negative correlation with P53 and KRAS immunoexpression in groups 4 and 5.

Conclusion

Higher expression of Reg IV in patients with UC-dysplasia and UC-CRC versus KRAS and P53 expression in sporadic CRC, suggests a potential role of Reg IV in UC carcinogenesis pathway. This could advocate the use of Reg IV as a screening biomarker for UC-N among patients with long-standing UC as well as a promising targeted therapeutic strategy.

Exploring the molecular mechanisms and shared gene signatures between celiac disease and ulcerative colitis based on bulk RNA and single-cell sequencing: Experimental verification

Many immune-mediated diseases have the common genetic basis, as an autoimmune disorder, celiac disease (CeD) primarily affects the small intestine, and is caused by the ingestion of gluten in genetically susceptible individuals. As for ulcerative colitis (UC), which most likely involves a complex interplay between some components of the commensal microbiota and other environmental factors in its origin. These two autoimmune diseases share a specific target organ, the bowel. The etiology and immunopathogenesis of both conditions characterized by chronic intestinal inflammation, ulcerative colitis and celiac disease, are not completely understood. Both are complex diseases with genetics and the environmental factors contributing to dysregulation of innate and adaptive immune responses, leading to chronic inflammation and disease. This study is designed to further clarify the relationship between UC and CeD. The GEO database was used to download gene expression profiles for CeD (GSE112102) and UC (GSE75214). The GSEA KEGG pathway analysis revealed that immune-related pathways were significantly associated with both diseases. Further, we screened 187 shared differentially expressed genes (DEGs) of the two diseases. Gene Ontology (GO) and WikiPathways were carried out to perform the biological process and pathway enrichment analysis. Subsequently, based on the DEGs, the least absolute shrinkage and selection operator (LASSO) analysis was performed to screen for the diagnostic biomarkers of the diseases. Moreover, single-cell RNA-sequencing (RNA-seq) data from five colonic propria with UC showed that REG4 expression was present in Goblet cell, Enteroendocrine cell, and Epithelial. Finally, our work identified REG4 is the shared gene of UC and CeD via external data validation, cellular experiments, and immunohistochemistry. In conclusion, our study elucidated that abnormal immune response could be the common pathogenesis of UC and CeD, and REG4 might be a key potential biomarker and therapeutic target for the comorbidity of these two diseases.

Regenerating gene 4 promotes chemoresistance of colorectal cancer by affecting lipid droplet synthesis and assembly

BACKGROUND

Regenerating gene 4 (REG4) has been proved to be carcinogenic in some cancers, but its manifestation and possible carcinogenic mechanisms in colorectal cancer (CRC) have not yet been elucidated. Our previous study found that the drug resistance of CRC cells may be closely linked to their fat metabolism.

AIM

To explore the role of REG4 in CRC and its association with lipid droplet formation and chemoresistance.

METHODS

We conducted a meta-analysis and bioinformatics and pathological analyses of REG4 expression in CRC. The effects of REG4 on the phenotypes and related protein expression were also investigated in CRC cells. We detected the impacts of REG4 on the chemoresistance and lipid droplet formation in CRC cells. Finally, we analyzed how REG4 regulated the transcription and proteasomal degradation of lipogenic enzymes in CRC cells.

RESULTS

Compared to normal mucosa, REG4 mRNA expression was high in CRC (P < 0.05) but protein expression was low. An inverse correlation existed between lymph node and distant metastases, tumor-node-metastasis staging or short overall survival and REG4 mRNA overexpression (P < 0.05), but vice versa for REG4 protein expression. REG4-related genes included: Chemokine activity; taste receptors; protein-DNA and DNA packing complexes; nucleosomes and chromatin; generation of second messenger molecules; programmed cell death signals; epigenetic regulation and DNA methylation; transcription repression and activation by DNA binding; insulin signaling pathway; sugar metabolism and transfer; and neurotransmitter receptors (P < 0.05). REG4 exposure or overexpression promoted proliferation, antiapoptosis, migration, and invasion of DLD-1 cells in an autocrine or paracrine manner by activating the epidermal growth factor receptor-phosphoinositide 3-kinase-Akt-nuclear factor-κB pathway. REG4 was involved in chemoresistance not through de novo lipogenesis, but lipid droplet assembly. REG4 inhibited the transcription of acetyl-CoA carboxylase 1 (ACC1) and ATP-citrate lyase (ACLY) by disassociating the complex formation of anti-acetyl (AC)-acetyl-histone 3-AC-histone 4-inhibitor of growth protein-5-si histone deacetylase;-sterol-regulatory element binding protein 1 in their promoters and induced proteasomal degradation of ACC1 or ACLY.

CONCLUSION

REG4 may be involved in chemoresistance through lipid droplet assembly. REG4 reduces expression of de novo lipid synthesis key enzymes by inhibiting transcription and promoting ubiquitination-mediated proteasomal degradation.

Intestinal Reg4 deficiency confers susceptibility to high-fat diet-induced liver steatosis by increasing intestinal fat absorption in mice

Background & Aims

Regenerating gene family member 4 (REG4) is a novel marker for enteroendocrine cells and is selectively expressed in specialised enteroendocrine cells of the small intestine. However, the exact roles of REG4 are largely unknown. In this study we investigate the effects of REG4 on the development of dietary fat-dependent liver steatosis and the mechanisms involved.

Methods

Mice with intestinal-specific Reg4 deficiency (Reg4 ^ΔIEC ) and Reg4-floxed alleles (Reg4 ^fl/fl ) were generated to investigate the effects of Reg4 on diet-induced obesity and liver steatosis. Serum levels of REG4 were also measured in children with obesity using ELISA.

Results

Reg4 ^ΔIEC mice fed a high-fat diet demonstrated significantly increased intestinal fat absorption and were prone to obesity and hepatic steatosis. Importantly, Reg4 ^ΔIEC mice exhibit enhanced activation of adenosine monophosphate-activated protein kinase (AMPK) signalling and increased protein abundance of the intestinal fat transporters, as well as enzymes involved in triglyceride synthesis and packaging at the proximal small intestine. Moreover, REG4 administration reduced fat absorption, and decreased the expression of intestinal fat absorption-related proteins in cultured intestinal cells possibly via the CaMKK2-AMPK pathway. Serum REG4 levels were markedly lower in children with obesity with advanced liver steatosis (p <0.05). Serum REG4 levels were inversely correlated with levels of liver enzymes, homeostasis model assessment of insulin resistance, low-density lipoprotein cholesterol, and triglycerides.

Conclusions

Our findings directly link Reg4 deficiency with increased fat absorption and obesity-related liver steatosis, and suggest that REG4 may provide a potential target for prevention and treatment of liver steatosis in children.

Impact and Implications

Hepatic steatosis is a key histological feature of non-alcoholic fatty liver disease, which is the leading chronic liver disease in children leading to the development of metabolic diseases; however, little is known about mechanisms induced by dietary fat. Intestinal REG4 acts as a novel enteroendocrine hormone reducing high-fat-diet-induced liver steatosis with decreasing intestinal fat absorption. REG4 may be a novel target for treatment of paediatric liver steatosis from the perspective of crosstalk between intestine and liver.

Clinical efficacy of moxibustion for ulcerative colitis and its influence on vitamin D receptor

Objective

To observe the clinical efficacy of herbal cake-partitioned moxibustion for ulcerative colitis (UC) and elucidate its mechanism by targeting the vitamin D receptor (VDR) signaling pathway.

Methods

A total of 63 patients with UC were randomly divided into an observation group (30 cases, treated with herbal cake-partitioned moxibustion) and a control group (33 cases, treated with sham herbal cake-partitioned moxibustion). Moxibustion treatment was performed at Qihai (CV6) and bilateral Tianshu (ST25) and Shangjuxu (ST37), 3 times per week for 12 weeks. The total effective rate, visual analog scale (VAS) score for abdominal bloating and pain, and hospital anxiety and depression scale (HADS) score were compared between the two groups. Enzyme-linked immunosorbent assay was used to detect the concentrations of serum C-reactive protein (CRP), 25-hydroxyvitamin D [25(OH)D], and interleukin-12 (IL-12)/interleukin-23 (IL-23) p40. Immunohistochemistry was used to observe the expression levels of VDR and regenerating gene IV (Reg IV) proteins in colonic mucosa. The expression levels of VDR, cytochrome p450 27B1 (CYP27B1), and Reg IV mRNAs were detected by real-time fluorescence quantitive polymerase chain reaction.

Results

After treatment, the total effective rate in the observation group was 86.7%, which was significantly higher than 51.5% in the control group (P<0.05). After treatment, the VAS scores for abdominal bloating and pain in the observation group were significantly decreased (P<0.01), as well as the HADS-depression subscale (HADS-D) and HADS-anxiety subscale (HADS) scores (P<0.05), while only the VAS score for abdominal pain in the control group was reduced (P<0.05), and the improvements of the scores in the observation group were more significant than those in the control group (P<0.05). After treatment, the serum CRP concentrations in both groups and the IL-12/IL-23 p40 concentration in the observation group were significantly decreased (P<0.05), and the concentrations in the observation group were lower than those in the control group (P<0.05). The expression levels of VDR protein and mRNA in the colon in both groups were all increased (P<0.01), and the expression levels of Reg IV protein and mRNA and CYP27B1 mRNA were all decreased in the two groups (P<0.05 or P<0.01); the improvements in the observation group were more notable than those in the control group (P<0.05 or P<0.01).

Conclusion

Herbal cake-partitioned moxibustion can effectively alleviate abdominal pain and diarrhea in patients with UC, improve depression and anxiety disorders, and regulate the expression of related proteins in the VDR signaling pathway. The mechanism may be related to inhibiting intestinal inflammation by reducing the release of the proinflammatory cytokine IL-12/IL-23 p40.

REG4 promotes the proliferation and anti-apoptosis of cancer

Regenerating islet-derived 4 (REG4) gene was discovered by high-throughput sequencing of ulcerative colitis cDNA libraries. REG4 is involved in infection and inflammation by enhancing macrophage polarization to M2, via activation of epidermal growth factor receptor (EGFR)/Akt/cAMP-responsive element binding and the killing inflammatory Escherichia coli, and closely linked to tumorigenesis. Its expression was transcriptionally activated by caudal type homeobox 2, GATA binding protein 6, GLI family zinc finger 1, SRY-box transcription factor 9, CD44 intracytoplasmic domain, activating transcription factor 2, and specificity protein 1, and translationally activated by miR-24. REG4 can interact with transmembrane CD44, G protein-coupled receptor 37, mannan and heparin on cancer cells. Its overexpression was observed in gastric, colorectal, pancreatic, gallbladder, ovarian and urothelial cancers, and is closely linked to their aggressive behaviors and a poor prognosis. Additionally, REG4 expression and recombinant REG4 aggravated such cellular phenotypes as tumorigenesis, proliferation, anti-apoptosis, chemoradioresistance, migration, invasion, peritoneal dissemination, tumor growth, and cancer stemness via EGFR/Akt/activator protein-1 and Akt/glycogen synthase kinase three β/β-catenin/transcription factor 4 pathways. Sorted REG4-positive deep crypt secretory cells promote organoid formation of single Lgr5 (+) colon stem cells by Notch inhibition and Wnt activation. Histologically, REG4 protein is specifically expressed in neuroendocrine tumors and signet ring cell carcinomas of the gastrointestinal tract, pancreas, ovary, and lung. It might support the histogenesis of gastric intestinal–metaplasia–globoid dysplasia–signet ring cell carcinoma. In this review, we summarized the structure, biological functions, and effects of REG4 on inflammation and cancer. We conclude that REG4 may be employed as a biomarker of tumorigenesis, subsequent progression and poor prognosis of cancer, and may be a useful target for gene therapy.

Clinicopathological Significance and Prognostic Implications of REG4 Immunohistochemical Expression in Colorectal Cancer

Background and objectives: The present study aimed to evaluate the clinicopathological significance and prognostic implications of REG4 immunohistochemical expression in colorectal cancer (CRC). Materials and Methods: We performed immunohistochemical analysis for REG4 cytoplasmic expression in 266 human CRC tissues. Correlations between REG4 expression, clinicopathological characteristics, and survival were investigated in CRC. Results: REG4 was expressed in 84 of 266 CRC tissues (31.6%). REG4 expression was significantly more frequent in the right colon than that in the left colon and rectum (p = 0.002). However, we observed no significant correlation between REG4 expression and other clinicopathological parameters. REG4 expression was significantly higher in CRCs with low stroma than in those with high stroma (p = 0.006). In addition, REG4 was more frequently expressed in CRCs with the mucinous component than in those without it (p < 0.001). There was no significant correlation between REG4 expression and overall recurrence-free survival (p = 0.132 and p = 0.480, respectively). Patients with REG4 expression showed worse overall and recurrence-free survival in the high-stroma subgroup (p = 0.001 and p = 0.017, respectively), but no such correlation was seen in the low stroma subgroup (p = 0.232 and p = 0.575, respectively). Conclusions: REG4 expression was significantly correlated with tumor location, amount of stroma, and mucinous component in CRCs. In patients with high stroma, REG4 expression was significantly correlated with poor overall and recurrence-free survival.

The Potential Role of REG Family Proteins in Inflammatory and Inflammation-Associated Diseases of the Gastrointestinal Tract

Regenerating gene (REG) family proteins serve as multifunctional secretory molecules with trophic, antiapoptotic, anti-inflammatory, antimicrobial and probably immuno-regulatory effects. Since their discovery, accumulating evidence has clarified the potential roles of the REG family in the occurrence, progression and development of a wide range of inflammatory and inflammation-associated diseases of the gastrointestinal (GI) tract. However, significant gaps still exist due to the undefined nature of certain receptors, regulatory signaling pathways and possible interactions among distinct Reg members. In this narrative review, we first describe the structural features, distribution pattern and purported regulatory mechanisms of REG family proteins. Furthermore, we summarize the established and proposed roles of REG proteins in the pathogenesis of various inflammation-associated pathologies of the GI tract and the body as a whole, focusing particularly on carcinogenesis in the ulcerative colitis—colitic cancer sequence and gastric cancer. Finally, the clinical relevance of REG products in the context of diagnosis, treatment and prognostication are also discussed in detail. The current evidence suggests a need to better understanding the versatile roles of Reg family proteins in the pathogenesis of inflammatory-associated diseases, and their broadened future usage as therapeutic targets and prognostic biomarkers is anticipated.

Role of the β-Catenin/REG Iα Axis in the Proliferation of Sessile Serrated Adenoma/Polyps Associated with Fusobacterium nucleatum

Although sessile serrated adenoma/polyps (SSA/Ps) may arise through a pathway different from the traditional adenoma–carcinoma sequence, details of SSA/P tumorigenesis still remain unclear. Fusobacterium nucleatum (Fn) is frequently detected in colorectal cancer (CRC) tissues and may play a pivotal role in colorectal carcinogenesis. Here, we investigated the relationship between Fn and the β-catenin/REG Iα axis in SSA/Ps and their involvement in the proliferation of these lesions. Fn was detected in SSA/Ps by fluorescence in situ hybridization using a Fn-targeted probe, and expression of β-catenin, REG Iα and Ki67 was examined using immunohistochemistry. Sixteen of 30 SSA/P lesions (53.3%) were positive for Fn. Eighteen SSA/P lesions (60%) showed β-catenin immunoreactivity in the tumor cell nuclei. A significant majority of Fn-positive lesions showed nuclear expression of β-catenin (87.5%) and higher REG Iα scores and Ki67 labeling indices relative to Fn-negative lesions. The SSA/P lesions expressing β-catenin in nuclei had significantly higher REG Iα scores and Ki67 labeling indices than those expressing β-catenin on cytomembranes. The REG Iα score was positively correlated with the Ki67 labeling index in SSA/P lesions. The treatment with Wnt agonist SKL2001 promoted nuclear β-catenin translocation and enhanced REG Ia expression in Caco2 cells. Fn may play a role in the proliferation of SSA/P lesions through promotion of β-catenin nuclear translocation and REG Iα expression.

CDX2 and Reg IV expression and correlation in gastric cancer

Background

Ectopic expression of CDX2 is associated with the development and progression of gastric cancer. Previous studies showed that CDX2 may be an upstream regulator of Reg IV expression in gastric cancer, and our previous report showed that Reg IV upregulated SOX9 expression and enhanced cell migration and invasion in gastric cancer cells. However, the regulatory roles of CDX2 have not been clarified in gastric cancer, and the correlation between CDX2 and Reg IV requires further study.

Methods

CDX2 and Reg IV were examined in gastric cancer specimens and paired adjacent tissues via real-time PCR and immunohistochemistry (IHC). The association between CDX2 and Reg IV was assessed using the χ²-test and Spearman’s rank correlation. To verify their relationship, knockdown and exogenous expression of CDX2 or Reg IV were performed in AGS and MKN-45 gastric cancer cells, and their expression was subsequently analyzed via a real-time PCR and western blotting. Wound-healing and Transwell assays were used to examine migration and invasion in AGS and MKN-45 cells following CDX2 silencing or overexpression.

Results

A positive correlation was observed between CDX2 and Reg IV expression at the mRNA and protein levels in gastric cancer tissues. CDX2 silencing significantly downregulated Reg IV expression, and CDX2 overexpression significantly upregulated Reg IV expression in AGS and MKN-45 cells. Neither Reg IV silencing nor overexpression had any effect on CDX2 protein expression in AGS or MKN-45 cells, even though both affected the expression of CDX2 mRNA. Functionally, CDX2 silencing significantly inhibited cell migration and invasion, and CDX2 overexpression significantly promoted cell migration and invasion in AGS and MKN-45 cells.

Conclusions

Our findings demonstrate that CDX2 expression was positively correlated with that of Reg IV in gastric cancer, and CDX2 promoted cell migration and invasion through upregulation of Reg IV expression in AGS and MKN-45 cells.

Protective and anti-inflammatory role of REG1A in inflammatory bowel disease induced by JAK/STAT3 signaling axis

Regenerating islet-derived protein 1-alpha (REG1A) was abnormally upregulated in a series of gastrointestinal inflammatory disorders. However, the potential biological function and underlying regulatory mechanisms of the increased REG1A in inflammatory bowel disease (IBD) pathogenesis remain to be fully elucidated. In this study, we uncovered that REG1A was substantially increased in the inflamed colorectal tissues of IBD patients. And the aberrantly expressed REG1A in intestinal epithelial cells (IEC) prominently inhibited inflammatory responses, promoted cell proliferation and suppressed epithelial apoptosis. Mechanically, IL-6 and IL-22 markedly activated REG1A transcription through triggering JAK/STAT3 signaling pathway. In addition, overexpression of REG1A in mice by systematic delivery of REG1A lentivirus remarkably alleviated DSS-induced inflammatory injury and maintained the integrity of intestinal mucosal barrier. Taken together, our data demonstrated that the novel proliferative factor REG1A controlled by IL-6/IL-22-JAK-STAT3 signaling may provide a promising therapeutic target for patients with IBD.

The Clinical Significance and Mechanisms of REG4 in Human Cancers

Regenerating islet-derived type 4 (REG4), a member of the calcium-dependent lectin gene superfamily, is abnormally expressed in various cancers, such as colorectal, gastric, gallbladder, pancreatic, ovarian, prostate, and lung cancer. REG4 is associated with a relatively unfavorable prognosis and clinicopathologic features in cancers, including advanced tumor and nodal stage, histological differentiation, and liver and peritoneal metastasis. Moreover, REG4-positive cancer cells show more frequent resistance to chemoradiotherapy, especially 5-FU-based chemotherapy. REG4 participates in many aspects of carcinogenesis, including cell proliferation, apoptosis, cell cycle, invasion, metastasis, and drug resistance. The underlying mechanisms are complex and involve a series of signaling mediators and multiple pathways. Thus, REG4 may be a potential diagnostic and prognostic biomarker as well as a candidate therapeutic target in cancer patients. In this review, we systematically summarize the advances about the clinical significance, biological functions, and mechanisms underlying REG4 in cancer to provide new directions for future cancer research.

Role of regenerating islet-derived proteins in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disorder of the gastrointestinal tract that affects millions of patients worldwide. It has a complex and multifactorial etiology leading to excessive exposure of intestinal epithelium to microbial antigens, inappropriate activation of the immune system and ultimately to the damage of intestinal tissues. Although numerous efforts have been made to improve the disease management, IBD remains persistently recurring and beyond cure. This is due largely to the gaps in our understanding of the pathogenesis of IBD that hamper the development of timely diagnoses and effective treatment. However, some recent discoveries, including the beneficial effects of interleukin-22 (IL-22) on the inflamed intestine, have shed light on a self-protective mechanism in IBD. Regenerating islet-derived (REG/Reg) proteins are small secretory proteins which function as IL-22's downstream effectors. Mounting studies have demonstrated that IBD patients have significantly increased REG expressions in the injured intestine, but with undefined mechanisms and roles. The reported functions of REG/Reg proteins in intestinal homeostasis, such as those of antibacterial, anti-inflammatory and tissue repair, lead us to discuss their potential mechanisms and clinical relevance in IBD in order to advance IBD research and management.

The Link between Type III Reg and STAT3-Associated Cytokines in Inflamed Colonic Tissues

Reg (regenerating gene) family proteins are known to be overexpressed in gastrointestinal (GI) tissues under conditions of inflammation. However, the pathophysiological significance of Reg family protein overexpression and its regulation is still unclear. In the present study, we investigated the profile of Reg family gene expression in a colitis model and focused on the regulation of Reg IIIβ and IIIγ, which are overexpressed in inflamed colonic mucosa. C57BL/6 mice were administered 2% dextran sulfate sodium (DSS) in drinking water for five days, and their colonic tissues were investigated histopathologically at interval for up to 12 weeks. Gene expression of the Reg family and cytokines (IL-6, IL-17, and IL-22) was evaluated by real-time RT-PCR, and Reg IIIβ/γ expression was examined by immunohistochemistry. The effects of cytokines on STAT3 phosphorylation and HIP/PAP (type III REG) expression in Caco2 and HCT116 cells were examined by Western blot analysis. Among Reg family genes, Reg IIIβ and IIIγ were alternatively overexpressed in the colonic tissues of mice with DSS-induced colitis. The expression of STAT3-associated cytokines (IL-6, IL-17, and IL-22) was also significantly increased in those tissues, being significantly correlated with that of Reg IIIβ/γ. STAT3 phosphorylation and HIP/PAP expression were significantly enhanced in Caco2 cells upon stimulation with IL-6, IL-17, and IL-22. In HCT116 cells, those enhancements were also observed by IL-6 and IL-22 stimulations but not IL-17. The link between type III Reg and STAT3-associated cytokines appears to play a pivotal role in the pathophysiology of DSS-induced colitis.

Four Decades After the Discovery of Regenerating Islet-Derived (Reg) Proteins: Current Understanding and Challenges

Regenerating islet-derived (Reg) proteins have emerged as multifunctional agents with pro-proliferative, anti-apoptotic, differentiation-inducing and bactericidal properties. Over the last 40 years since first discovered, Reg proteins have been implicated in a gamut of maladies including diabetes, various types of cancer of the digestive tract, and Alzheimer disease. Surprisingly though, a consensus is still absent on the regulation of their expression, and molecular underpinning of their function. Here, we provide a critical appraisal of recent findings in the field of Reg protein biology. Specifically, the structural characteristics are reviewed particularly in connection with established or purported functions of different members of the Reg family. Moreover, Reg expression patterns in different tissues both under normal and pathophysiological conditions are summarized. Putative receptors and cascades reported to relay Reg signaling inciting cellular responses are presented aiming at a better appreciation of the biological activities of the distinct Reg moieties. Challenges are also discussed that have hampered thus far the rapid progress in this field such as the use of non-standard nomenclature for Reg molecules among various research groups, the existence of multiple Reg members with significant degree of homology and possibly compensatory modes of action, and the need for common assays with robust readouts of Reg activity. Coordinated research is warranted going forward, given that several research groups have independently linked Reg proteins to diseased states and raised the possibility that these biomolecules can serve as therapeutic targets and biomarkers.

Establishment of a system to evaluate the therapeutic effect and the dynamics of an investigational drug on ulcerative colitis using human colonic organoids

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon with an intractable, recurrent course. The goal of UC therapy is to target mucosal healing because immune-suppressive therapy for UC frequently results in relapse. However, few drugs directly target mucosal healing. We, therefore, aim to evaluate the therapeutic effect of an investigational drug on intestinal epithelial cells in an in vitro UC model using human colonic organoids.

METHODS

Colonic organoids were isolated from human colon and cultured. A mixture of cytokines and bacterial components were used to mimic UC in humans. The effect of the investigational drug on colonic organoid was evaluated by microarray analysis and 3D immunofluorescence. The enrichment of stem cells was assessed with a colony formation assay.

RESULTS

Inflammatory stimulation resulted in a significant induction of inflammatory-related genes in colonic organoids whereas cell differentiation was suppressed. Treatment with the investigational drug KAG-308 showed reciprocal dynamics of gene expression to inflammatory stimulation, which resulted in not only the suppression of immune response but also the promotion of cellular differentiation towards secretory lineages. Moreover, SPDEF and Reg4 were identified as novel targets for the enrichment of intestinal epithelial stem cells and mucosal healing.

CONCLUSIONS

The establishment of in vitro UC model using human colonic organoid could reveal the effects and targets of investigational drugs in intestinal epithelial cells under inflammation conditions. Further maturation of this system might be more efficient to predict the effect on UC, as compared with the use of animal model, for the development of new drugs.

High-Throughput Identification of the Plasma Proteomic Signature of Inflammatory Bowel Disease

BACKGROUND

The molecular aetiology of inflammatory bowel disease [IBD] and its two subtypes, ulcerative colitis [UC] and Crohn's disease [CD], have been carefully investigated at genome and transcriptome levels. Recent advances in high-throughput proteome quantification has enabled comprehensive large-scale plasma proteomics studies of IBD.

METHODS

The study used two cohorts: [1] The CERTIFI-cohort: 42 samples from the CERTIFI trial of anti-TNFα-refractory CD patients; [2] the PROgECT-UNITI-HCs cohort: 46 UC samples of the PROgECT study, 84 CD samples of the UNITI I and UNITI II studies, and 72 healthy controls recruited in Mount Sinai Hospital, New York, USA. The plasma proteome for these two cohorts was quantified using high-throughput platforms.

RESULTS

For the PROgECT-UNITI-HCs cohort, we measured a total of 1310 proteins. Of these, 493 proteins showed different plasma levels in IBD patients to the plasma levels in controls at 10% false discovery rate [FDR], among which 11 proteins had a fold change greater than 2. The proteins upregulated in IBD were associated with immunity functionality, whereas the proteins downregulated in IBD were associated with nutrition and metabolism. The proteomic profiles were very similar between UC and CD. In the CERTIFI cohort, 1014 proteins were measured, and it was found that the plasma protein level had little correlation with the blood or intestine transcriptomes.

CONCLUSIONS

We report the largest proteomics study to date on IBD and controls. A large proportion of plasma proteins are altered in IBD, which provides insights into the disease aetiology and indicates a potential for biomarker discovery.

Deficiency in intestinal epithelial Reg4 ameliorates intestinal inflammation and alters the colonic bacterial composition

The regenerating islet-derived family member 4 (Reg4) in the gastrointestinal tract is up-regulated during intestinal inflammation. However, the physiological function of Reg4 in the inflammation is largely unknown. In the current study, the functional roles and involved mechanisms of intestinal epithelial Reg4 in intestinal inflammation were studied in healthy and inflamed states using human intestinal specimens, an intestinal conditional Reg4 knockout mouse (Reg4^ΔIEC) model and dextran sulfate sodium (DSS)-induced colitis model. We showed that the elevated serum Reg4 in pediatric intestinal failure (IF) patients were positively correlated with the serum concentrations of proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). In inflamed intestine of IF patients, the crypt base Reg4 protein was increased and highly expressed towards the luminal face. The Reg4 was indicated as a novel target of activating transcription factor 2 (ATF2) that enhanced Reg4 expression during the intestinal inflammation. In vivo, the DSS-induced colitis was significantly ameliorated in Reg4^ΔIEC mice. Reg4^ΔIEC mice altered the colonic bacterial composition and reduced the bacteria adhere to the colonic epithelium. In vitro, Reg4 was showed to promote the growth of colonic organoids, and that this occurs through a mechanism involving activation of signal transducer and activator of transcription 3 (STAT3). In conclusion, our findings demonstrated intestinal-epithelial Reg4 deficiency protects against experimental colitis and mucosal injury via a mechanism involving alteration of bacterial homeostasis and STAT3 activation.

Expression of REG family genes in human inflammatory bowel diseases and its regulation

The pathophysiology of inflammatory bowel disease (IBD) reflects a balance between mucosal injury and reparative mechanisms. Some regenerating gene (Reg) family members have been reported to be expressed in Crohn's disease (CD) and ulcerative colitis (UC) and to be involved as proliferative mucosal factors in IBD. However, expression of all REG family genes in IBD is still unclear. Here, we analyzed expression of all REG family genes (REG Iα, REG Iβ, REG III, HIP/PAP, and REG IV) in biopsy specimens of UC and CD by real-time RT-PCR. REG Iα, REG Iβ, and REG IV genes were overexpressed in CD samples. REG IV gene was also overexpressed in UC samples. We further analyzed the expression mechanisms of REG Iα, REG Iβ, and REG IV genes in human colon cells. The expression of REG Iα was significantly induced by IL-6 or IL-22, and REG Iβ was induced by IL-22. Deletion analyses revealed that three regions (- 220 to - 211, - 179 to - 156, and - 146 to - 130) in REG Iα and the region (- 274 to- 260) in REG Iβ promoter were responsible for the activation by IL-22/IL-6. The promoters contain consensus transcription factor binding sequences for MZF1, RTEF1/TEAD4, and STAT3 in REG Iα, and HLTF/FOXN2F in REG Iβ, respectively. The introduction of siRNAs for MZF1, RTEF1/TEAD4, STAT3, and HLTF/FOXN2F abolished the transcription of REG Iα and REG Iβ. The gene activation mechanisms of REG Iα/REG Iβ may play a role in colon mucosal regeneration in IBD.

GlycoGAIT: A web database to browse glycogenes and lectins under gastric inflammatory diseases

The perplexing nature of dynamic glycosylation modification plays imperative role in determining the regulatory role of key glycoconjugates involved in immune system. Systematic analysis of change in expression pattern of glycogenes and lectins can bring in a comprehensive understanding of genetic basis of the glycobiological changes occurring in pathological condition. Advancement in the field of glycobiology has capacitated the process of linking gene expression changes of glycogenes with its biological function. This instigated us to systematically analyze changes in expression patterns focusing on glycome genomics under diverse gastrointestinal immune dysfunction background. To necessitate this, as a pilot project, we carefully integrated several publically available databases to construct a glycosylation process associated gene set as well as public expression microarray data associated with gastrointestinal infections into an online database called Glycosylation and Gut Associated Immune Tolerance (GlycoGAIT). Currently the database comprises of 548 well characterized genes belonging to glycogenes and lectins along with gene expression data obtained from human biopsy samples under both H. pylori infection and inflammatory bowel disease (IBD) condition. The user-friendly interface enables the users to quickly compare and interpret changes in expression patterns of glycome genomics under different gut associated inflammatory conditions. The database is available online at: https://apps.connexios.com/glycogait/.

REG4 promotes peritoneal metastasis of gastric cancer through GPR37

Being the major reason of recurrence and death after surgery, peritoneal metastasis of gastric cancer dooms the prognosis of advanced gastric cancer patients. Regenerating islet-derived family, member 4 (REG4) is believed to promote peritoneal metastasis, however, its mechanism is still a moot point at present. In the present study, we show that high expression of REG4 correlates with advanced stage and poor survival prognosis for gastric cancer patients. REG4 overexpression significantly enhances peritoneal metastasis by increasing adhesion ability. Moreover, SP1 is proved to be a transcription factor of REG4 and induce REG4 expression upon TGF-alpha stimulation. Also, G protein-coupled receptor 37 (GPR37) is identified to be in the same complex of REG4, which mediates REG4's signal transduction and promotes peritoneal metastasis of gastric cancer cell. Interestingly, we also discover a positive feedback loop triggered by REG4, amplifying itself through EGFR transactivation, consisting of GPR37, ADAM17, TGF-alpha, EGFR, SP1 and REG4. In conclusion, REG4 promotes peritoneal metastasis of gastric cancer through GPR37 and triggers a positive feedback loop.

Comparison of Gene Expression Between Pediatric and Adult Gastric Mucosa with Helicobacter pylori Infection

BACKGROUND

Although Helicobacter pylori infection among adults is a major risk factor for the development of gastric cancer and initial infection with H. pylori may occur before 5 years of age, the direct effects of H. pylori infection since childhood on gastric mucosa are unknown. The aim of this study was to evaluate gene expression in the H. pylori-infected gastric mucosa of children.

METHODS

Gastric mucosal samples were obtained from 24 patients (12 adults and 12 children) who had undergone endoscopic evaluation of chronic abdominal complaints and were examined by the adult and pediatric gastroenterologists at Juntendo University Hospital. Six adult and pediatric patients with and six without H. pylori infection were enrolled. Their gastric mucosal samples obtained from the antrum and corpus were used for microarray, real-time polymerase chain reaction, and immunohistochemical analyses to examine the expression of inflammatory carcinogenic molecules.

RESULTS

The expression of inflammatory molecules was upregulated in the H. pylori-infected gastric mucosa from both adults and children. The expression of olfactomedin-4 was only upregulated in adult patients, while that of pim-2, regenerating islet-derived 3 alpha, lipocalin-2, and C-X-C motif chemokine ligand 13 was equally upregulated in the infected gastric mucosa of both adults and children.

CONCLUSIONS

Because several carcinogenic molecules are upregulated in H. pylori-infected gastric mucosa even in children, early eradication therapy from childhood may be beneficial to decrease the incidence of gastric cancer. Although increased expression of olfactomedin-4 can be important in suppressing gastric cancer in adults, the increase was not detected in children.

Regenerating gene (REG) product and its potential clinical usage

INTRODUCTION

The regenerating gene (Reg) was identified in regenerating islets and its related genes were revealed to constitute the Reg gene family. Reg family proteins act as growth factors for several cells. Recently, autoimmunity against the Reg family proteins has been reported in several diseases. In addition, the Reg family genes were found to be expressed in a large number of cancers and to influence prognosis.

AREAS COVERED

The historical background and current view of the structure, function, and expression of Reg family genes/proteins and their physiological/pathological significance in several diseases are described. Based on the findings, the diagnostic/therapeutic potential of Reg family genes/proteins is also discussed.

EXPERT OPINION

Autoimmunity against Reg family proteins may be a new diagnostic marker and/or therapeutic target for immune-mediated diseases. Treatment aimed at the expansion of the β-cell mass by the Reg genes/proteins, combined with the abrogation of autoimmunity, constitutes a potential approach for the treatment of diabetes. Conversely, some cancer cells have gained the ability to overexpress the Reg genes/proteins, thereby enhancing their proliferative capacities, resulting in these cells having a considerable growth advantage. Thus, the Reg genes/proteins are expected to be a new prognostic marker in cancer and/or a future therapeutic target.

The role of Reg IV in colorectal cancer, as a potential therapeutic target

Regenerating islet-derived family, member 4 (Reg IV), a member of the Reg gene family, has been reported to be overexpressed in gastrointestinal tract cancers. Reg IV overexpression in tumor cells has been associated with carcinogenesis, tissue regeneration, proliferation and resistance to apoptosis. Reg IV activates the epidermal growth factor receptor (EGFR) signaling pathway in colon cancer and increases expression of B-cell lymphoma-2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xl), which are associated with the inhibition of apoptosis, results in mitogenic signaling in colon cancer cells, increase cell proliferation, metastasis and decreased apoptosis. Reg IV treatment inhibits 5-fluorouracil induced apoptosis, at least two mechanisms are involved in inhibition of apoptosis by Reg IV, including Bcl-2 and dihydropyrimidine dehydrogenase (DPD). These studies may lead to novel therapeutic strategies for cancers expressing Reg IV. Recently, one proteoglycan was confirmed to disrupt this signaling pathway to perform antitumor effect. This review summaries current knowledge of the expression and roles of Reg IV in human colorectal cancer, describes the possible signaling pathway which Reg IV activates, and discusses the relevance of Reg IV as a potential therapeutic target for cancer treatment.

The role of the REG4 gene and its encoding product in ovarian epithelial carcinoma

BACKGROUND

Although its biological function remains poorly understood, REG4 is reported to be a potent activator of the EGFR/Akt/AP-1 signaling pathway in colon cancer cells and closely linked with the inhibition of apoptosis.

METHODS

SKOV3 cells were transfected with a REG4-expressing plasmid or treated with recombinant REG4. We then analyzed proliferation, cell cycle, apoptosis, invasion and metastasis or expression of related molecules. REG4 expression was examined in normal ovarian tissue, benign and borderline tumors, and cancers by immunohistochemistry or real-time PCR.

RESULTS

REG4 overexpression and the recombinant protein inhibited cell apoptosis, enhanced G2/S progression, proliferation, migration and invasion. Furthermore, expression of Wnt5a, p70s6k, survivin and VEGF expression was increased, while Bax expression was decreased at both the mRNA and protein levels compared to control or mock cells (P<0.05). REG4 mRNA levels were higher in benign tumors and primary cancer compared to those in normal ovarian tissue (P<0.05) while, REG4 protein expression was higher in all three tumor types than that in normal ovarian tissue (P<0.05). Higher REG4 mRNA expression was observed in mucinous carcinomas than serous carcinomas (P<0.05), and in well- and moderately-differentiated carcinomas than poorly-differentiated carcinomas (P<0.05). Survival analysis revealed an inverse relationship between REG4 expression and cumulative or relapse-free survival rates of the patients with ovarian cancer as an independent factor (P<0.05).

CONCLUSIONS

Our findings indicate that aberrant REG4 expression plays an essential role in early ovarian carcinogenesis and is closely linked to mucinous ovarian tumors, differentiation and adverse prognosis of ovarian cancer by modulating proliferation, apoptosis, migration and invasion.

The PAS positive material in gastric cancer cells of signet ring type is not mucin

PURPOSE

The purpose of this study is to assess the exocrine and neuroendocrine properties of tumour cells in diffuse gastric cancer with signet ring cell differentiation.

MATERIAL AND METHODS

Mucin mRNA and protein expressions (MUC1, 2, 3, 4, 5AC, 6 and MUC13) were assessed by immunohistochemistry and in situ hybridization. The neuroendocrine properties were evaluated by protein and mRNA expression of the general neuroendocrine markers chromogranin A and synaptophysin.

RESULTS

No MUC expression was observed in signet ring tumour cells including the amorphous substance in any of the nine cases. All cases showed immunoreactivity to synaptophysin, and seven out of nine cases immunoreactivity to chromogranin A in signet ring and non-signet ring tumour cells. Chromogranin A mRNA expression was observed in tumour cells in all samples with retained mRNA.

CONCLUSIONS

The lack of MUC protein and mRNA in signet ring tumour cells suggests the amorphous substance is not mucin. The lack of MUC mRNA expression in non-signet ring tumour cells questions exocrine differentiation in this tumour group. The abundant protein expression of the general neuroendocrine markers CgA and synaptophysin, and mRNA expression in tumour cells strengthens the hypothesis that this tumour group may be of neuroendocrine origin.

Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs.

Reg proteins and their roles in inflammation and cancer of the human digestive system

The regenerating gene (Reg) family is a group of small molecules that includes four members found in various species, although only three are found in human tissues. Their expression is stimulated by certain growth factors or cytokines. The Reg family plays different roles in proliferation, migration, and anti-apoptosis through activating different signaling pathways. Their dysexpression is closely associated with a number of human conditions and diseases such as inflammation and cancer, especially in the human digestive system. Clinically, upregulation of Reg proteins is usually demonstrated in histological sections and sera from cancer patients. Therefore, Reg proteins can predict the progression and prognosis of cancers, especially those of the digestive tract, and can also act as diagnostic markers and therapeutic targets.

Transcriptional analysis of the intestinal mucosa of patients with ulcerative colitis in remission reveals lasting epithelial cell alterations

OBJECTIVE

Ulcerative colitis (UC) is a chronic condition characterised by the relapsing inflammation despite previous endoscopic and histological healing. Our objective was to identify the molecular signature associated with UC remission.

DESIGN

We performed whole-genome transcriptional analysis of colonic biopsies from patients with histologically active and inactive UC, and non-inflammatory bowel disease (non-IBD) controls. Real-time reverse transcriptase-PCR and immunostaining were used for validating selected genes in independent cohorts of patients.

RESULTS

Microarray analysis (n=43) demonstrates that UC patients in remission present an intestinal transcriptional signature that significantly differs from that of non-IBD controls and active patients. Fifty-four selected genes were validated in an independent cohort of patients (n=30). Twenty-nine of these genes were significantly regulated in UC-in-remission subjects compared with non-IBD controls, including a large number of epithelial cell-expressed genes such as REG4, S100P, SERPINB5, SLC16A1, DEFB1, AQP3 and AQP8, which modulate epithelial cell growth, sensitivity to apoptosis and immune function. Expression of inflammation-related genes such as REG1A and IL8 returned to control levels during remission. REG4, S100P, SERPINB5 and REG1A protein expression was confirmed by immunohistochemistry (n=23).

CONCLUSIONS

Analysis of the gene signature associated with remission allowed us to unravel pathways permanently deregulated in UC despite histological recovery. Given the strong link between the regulation of some of these genes and the growth and dissemination of gastrointestinal cancers, we believe their aberrant expression in UC may provide a mechanism for epithelial hyper-proliferation and, in the context of malignant transformation, for tumour growth.

Reg IV is differently expressed in enteroendocrine cells of human small intestine and colon

Reg IV is a 17 kD secreted C-type lectin physiologically found in selected enteroendocrine cells (EEC). It is thought be involved in the regulation of normal and pathological intestinal and/or neuroendocrine differentiation and proliferation but its ultimate functional role(s) is still unclear. We used immunostaining and compared the cellular expression of Reg IV with a panel of neuroendocrine markers in human GI-tract tissue samples. Reg IV showed cellular co-distribution with serotonin and chromogranin A in all parts of GI-tract. Co-localization of Reg IV with somatostatin was seen in colon and with substance P in ileum. Subpopulations of cells expressing Reg IV overlapped with EECs containing GLP-1, GLP-2, secretin, PYY, and ghrelin, depending on the anatomical localization of the samples. The results further underscore the high degree of diversity among EECs and suggest that Reg IV may be involved in the finetuning of functions exerted by the neuroendocrine cells in the GI-tract.

In vivo targeting of ADAM9 gene expression using lentivirus-delivered shRNA suppresses prostate cancer growth by regulating REG4 dependent cell cycle progression

Cancer cells respond to stress by activating a variety of survival signaling pathways. A disintegrin and metalloproteinase (ADAM) 9 is upregulated during cancer progression and hormone therapy, functioning in part through an increase in reactive oxygen species. Here, we present in vitro and in vivo evidence that therapeutic targeting of ADAM9 gene expression by lentivirus-delivered small hairpin RNA (shRNA) significantly inhibited proliferation of human prostate cancer cell lines and blocked tumor growth in a murine model of prostate cancer bone metastasis. Cell cycle studies confirmed an increase in the G1-phase and decrease in the S-phase population of cancer cells under starvation stress conditions, which correlated with elevated intracellular superoxide levels. Microarray data showed significantly decreased levels of regenerating islet-derived family member 4 (REG4) expression in prostate cancer cells with knockdown of ADAM9 gene expression. This REG4 downregulation also resulted in induction of expression of p21^Cip1/WAF1, which negatively regulates cyclin D1 and blocks the G1/S transition. Our data reveal a novel molecular mechanism of ADAM9 in the regulation of prostate cancer cell proliferation, and suggests a combined modality of ADAM9 shRNA gene therapy and cytotoxic agents for hormone refractory and bone metastatic prostate cancer.

Reg IV is a direct target of intestinal transcriptional factor CDX2 in gastric cancer

REG4, which encodes Reg IV protein, is a member of the calcium-dependent lectin superfamily and potent activator of the epidermal growth factor receptor/Akt/activator protein-1 signaling pathway. Several human cancers overexpress Reg IV, and Reg IV expression is associated with intestinal phenotype differentiation. However, regulation of REG4 transcription remains unclear. In the present study, we investigated whether CDX2 regulates Reg IV expression in gastric cancer (GC) cells. Expression of Reg IV and CDX2 was analyzed by Western blot and quantitative reverse transcription–polymerase chain reaction in 9 GC cell lines and 2 colon cancer cell lines. The function of the 5′-flanking region of the REG4 gene was characterized by luciferase assay. In 9 GC cell lines, endogenous Reg IV and CDX2 expression were well correlated. Using an estrogen receptor-regulated form of CDX2, rapid induction of Reg IV expression was observed in HT-29 cells. Reporter gene assays revealed an important role in transcription for consensus CDX2 DNA binding elements in the 5′-flanking region of the REG4 gene. Chromatin immunoprecipitation assays showed that CDX2 binds directly to the 5′-flanking region of REG4. These results indicate that CDX2 protein directly regulates Reg IV expression.

Oncogenic reg IV is a novel prognostic marker for glioma patient survival

Aim

The aberrant expression of regenerating islet-derived family member, 4 (Reg IV) has been found in various human cancers. However, the roles of Reg IV gene and its encoding product in human glioma have not been clearly understood. Therefore, the aim of this study was to investigate the clinicopathological significance of Reg IV expression in glioma.

Methods

Reg IV mRNA and protein expression in human gliomas and non-neoplastic brain tissues were respectively detected by real-time quantitative RT-PCR assay, Western blot, and immunohistochemistry. The association of Reg IV immunostaining with clinicopathological factors and prognosis of glioma patients was also statistically analyzed.

Results

Reg IV mRNA and protein expression levels in glioma tissues were both significantly higher than those in the corresponding non-neoplastic brain tissues (both P < 0.001). Additionally, the increased Reg IV immunostaining in glioma tissues was significantly associated with advanced pathological grade (P = 0.008). Reg IV protein up-regulation was also significantly correlated with low Karnofsky performance score (KPS) (P = 0.02). Moreover, the overall survival of patients with high Reg IV protein expression was dramatically shorter than those with low Reg IV protein expression (P < 0.001). Multivariate Cox regression analysis further confirmed that Reg IV expression was an independent prognostic factor for patients with gliomas (P = 0.008).

Conclusions

These convinced evidences suggest for the first time that Reg IV might accelerate disease progression and act as a candidate prognostic marker for gliomas.

Virtual slides

The virtual slide(s) for this article can be found here:

http://www.diagnosticpathology.diagnomx.eu/vs/2145344361720706

Effect of oral hepatocyte growth factor gene mediated by attenuated salmonella on 2-, 4-, 6-trinitro-benzene-sulfonic-acid-induced ulcerative colitis in rat

BACKGROUND AND AIM

In order to explore a new therapeutic method, we investigated the effects of exogenously expressed hepatocyte growth factor mediated by attenuated salmonella (TPH) on rats with ulcerative colitis (UC) induced by 2-, 4-, 6-trinitro-benzene-sulfonic acid.

METHODS

The UC rats were treated with TPH, attenuated salmonella with a eukaryotic expression vector (TP) or sodium bicarbonate (model control [MC]) every other day. Cluster of differentiation (CD)4(+) and CD8(+) T cells and immunoglobulins in the blood were analyzed by flow cytometry. The HGF expression was determined by immunohistochemistry. A macroscopic-scale observation of the colon and a histological assessment were also carried out.

RESULTS

The CD4(+) T counts and the CD4(+) /CD8(+) ratio in the TPH group were significantly lower than that in the MC group. The immunoglobulin M and immunoglobulin G(1) levels in the TPH group were significantly lower than that in the MC group and TP group. After treatment with TPH, the symptoms of the ulcerative rats were significantly alleviated. The colonic lesion grades in the TPH group were lower than that in the TP group and MC group. Significant improvement occurred after the TPH treatment, as evidenced by alleviated mucosal inflammation. At 7 days post-treatment, the HGF expression in the colonic tissues that were treated with TPH was stronger than that in the samples treated with TP.

CONCLUSIONS

TPH inhibits the proliferation of T lymphocytes and the antibody production of B lymphocytes. Furthermore, it ameliorates mucosal inflammation and promotes the regeneration of mucosa and the healing of the colonic ulceration.

Regenerating gene (REG) 1 alpha promotes pannus progression in patients with rheumatoid arthritis

INTRODUCTION

A protein analysis using mass spectrometry revealed the existence of serum proteins with significant quantitative changes after the administration of infliximab. Among these proteins, regenerating gene (REG) 1α appears to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, the present study was conducted to examine the mechanism of REG1α in RA disease progression.

METHODS

Serum samples were collected from RA patients and normal healthy controls. REG1α expression was evaluated by ELISA, RT-PCR, and indirect immunofluorescence microscopy. The functions of REG1α on synovial fibroblasts with regard to apoptosis, receptor activator of NF-κB ligand (RANKL) expression, and cellar proliferation were evaluated using siRNA to inhibit the intrinsic REG1α mRNA expression.

RESULTS

The serum concentrations of REG1α in RA patients were higher than in normal healthy controls. The high expression of REG1α was also observed in the synovial tissue of RA patients compared to those of osteoarthropathy patients. In addition, tumor necrosis factor-α (TNF-α) upregulated REG1α expression in the synovial fibroblasts cell line (MH7A). Inhibition of REG1α expression suppressed the induction of RANKL expression by TNF-α. Furthermore, exogenous recombinant REG1α protein inhibited apoptosis and promoted cell proliferation in MH7A cells. These effects were abolished in the REG1α-siRNA MH7A cells.

CONCLUSION

The present data suggest that TNF-α induces aberrant REG1α expression and that REG1α plays an important role in aberrant cell proliferation and RANKL expression of synovial fibroblasts, ultimately resulting in pannus formation. Restoration of normal physiological REG1α expression may contribute to disease amelioration.

Reg IV protein and mRNA expression in different rat organs

The Reg IV gene has been documented in the human colon, small intestine, stomach and pancreas. Expression of the Reg IV in different cell types has been associated with regeneration, cell growth and cell survival, cell adhesion and resistance to apoptosis. Since the distribution of the Reg IV protein in normal rat tissues is unknown, the aim of this study was to reveal the expression of the Reg IV protein in structurally and functionally different rat organs. The expression of Reg IV gene was analyzed by Western blot and reverse transcription-polymerase chain reaction. Immunohistochemistry was used to localize Reg IV protein. Reg IV protein was expressed in pancreas, stomach, small intestine, colon, brain, spleen, kidney and urinary bladder in two-month-old male Wistar rats. In addition, the expression of Reg IV mRNA by reverse transcription-polymerase chain reaction was confirmed. Our study provides detailed information about the expression and localization of Reg IV protein in different rat organs. These findings provide an evidence of Reg IV expression in different rat organs, which may help elucidate a potential role in growth and proliferation of different cells like other members of the Reg family genes which act as growth factors in the different organs.

Regenerating proteins and their expression, regulation and signaling

The regenerating (Reg) protein family comprises C-type lectin-like proteins discovered independently during pancreatitis and pancreatic islet regeneration. However, an increasing number of studies provide evidence of participation of Reg proteins in the proliferation and differentiation of diverse cell types. Moreover, Reg family members are associated with various pathologies, including diabetes and forms of gastrointestinal cancer. These findings have led to the emergence of key roles for Reg proteins as anti-inflammatory, antiapoptotic and mitogenic agents in multiple physiologic and disease contexts. Yet, there are significant gaps in our knowledge regarding the regulation of expression of different Reg genes. In addition, the pathways relaying Reg-triggered signals, their targets and potential cross-talk with other cascades are still largely unknown. In this review, the expression patterns of different Reg members in the pancreas and extrapancreatic tissues are described. Moreover, factors known to modulate Reg levels in different cell types are discussed. Several signaling pathways, which have been implicated in conferring the effects of Reg ligands to date, are also delineated. Further efforts are necessary for elucidating the biological processes underlying the action of Reg proteins and their involvement in various maladies. Better understanding of the function of Reg genes and proteins will be beneficial in the design and development of therapies utilizing or targeting this protein group.

Identification of RegIV as a novel GLI1 target gene in human pancreatic cancer

BACKGROUND AND AIMS

GLI1 is the key transcriptional factor in the Hedgehog signaling pathway in pancreatic cancer. RegIV is associated with regeneration, and cell growth, survival, adhesion and resistance to apoptosis. We aimed to study RegIV expression in pancreatic cancer and its relationship to GLI1.

METHODS

GLI1 and RegIV expression were evaluated in tumor tissue and adjacent normal tissues of pancreatic cancer patients and 5 pancreatic cancer cell lines by qRT-PCR, Western blot, and immunohistochemistry (IHC), and the correlation between them. The GLI1-shRNA lentiviral vector was constructed and transfected into PANC-1, and lentiviral vector containing the GLI1 expression sequence was constructed and transfected into BxPC-3. GLI1 and RegIV expression were evaluated by qRT-PCR and Western blot. Finally we demonstrated RegIV to be the target of GLI1 by chromatin immunoprecipitation (CHIP) and electrophoretic mobility shift assays (EMSA).

RESULTS

The results of IHC and qRT-PCR showed that RegIV and GLI1 expression was higher in pancreatic cancer tissues versus adjacent normal tissues (p<0.001). RegIV expression correlated with GLI1 expression in these tissues (R = 0.795, p<0.0001). These results were verified for protein (R = 0.939, p = 0.018) and mRNA expression (R = 0.959, p = 0.011) in 5 pancreatic cancer cell lines. RegIV mRNA and protein expression was decreased (94.7±0.3%, 84.1±0.5%; respectively) when GLI1 was knocked down (82.1±3.2%, 76.7±2.2%; respectively) by the RNAi technique. GLI1 overexpression in mRNA and protein level (924.5±5.3%, 362.1±3.5%; respectively) induced RegIV overexpression (729.1±4.3%, 339.0±3.7%; respectively). Moreover, CHIP and EMSA assays showed GLI1 protein bound to RegIV promotor regions (GATCATCCA) in pancreatic cancer cells.

CONCLUSION

GLI1 promotes RegIV transcription by binding to the RegIV gene promoter in pancreatic cancer.

RegIV expression showing specificity to gastrointestinal tract and its potential role in diagnosing digestive tract neuroendocrine tumor

Regenerating gene IV (RegIV), a member of the regenerating gene family discovered in 2001, has been found to be involved in malignancy in several different organs including the stomach, colorectum, pancreas and prostate, but the overall expression profile of RegIV has not been reported. To learn more about RegIV, we evaluated its distribution by immunohistochemistry (IHC) in a total of 360 samples including 24 types of normal tissue, 40 benign and malignant lesions, and 18 neuroendocrine tumors. We found that in normal tissues, in addition to its relative specificity for the gastrointestinal tract, RegIV was detected in the adrenal gland and mammary gland. Among all the malignancies of various histological types under evaluation, RegIV was found mostly in adenocarcinomas. Studies on additional sets of colorectal tumor samples showed that RegIV expression was predominant in colorectal adenoma (87.5%) and peritumoral tissue (100%) but not in cancer tissue (30.8%). Among neuroendocrine tumors, RegIV had a relatively restricted expression to those of digestive system.

Involvement of the IL-22/REG Ialpha axis in ulcerative colitis

The Regenerating gene (REG) Ialpha protein, a trophic and/or anti-apoptotic factor, is important in the pathophysiology of gastrointestinal inflammation. Interleukin (IL)-22 is a recently identified cytokine that is suggested to have pivotal roles in inflammatory bowel diseases. We therefore investigated the involvement of the IL-22/REG Ialpha axis and examined the mechanism of regulation of REG Ialpha expression by IL-22 stimulation in ulcerative colitis (UC) mucosa. Expression of IL-22, IL-22 receptor 1 (IL-22R1), and REG Ialpha in UC mucosa was analyzed by real-time RT-PCR and immunohistochemistry. The effects of IL-22 on REG Ialpha protein expression were examined using a small-interfering RNA for STAT3, an MAPK inhibitor or a PI3K inhibitor. The element responsible for IL-22-induced REG Ialpha promoter activation was determined by a promoter deletion and electrophoretic mobility shift assay. The expression of IL-22 was enhanced in infiltrating inflammatory cells, and that of IL-22R1 and REG Ialpha was concurrently enhanced in the inflamed epithelium in UC mucosa. The levels of REG Ialpha and IL-22 mRNA expression were strongly correlated, and the distributions of REG Ialpha- and IL-22R1-positive epithelial cells were very similar. IL-22 simulation enhanced the expression of REG Ialpha protein through STAT3 tyrosine phosphorylation in colon cancer cells. The IL-22-responsive element was located between -142 and -134 in the REG Ialpha promoter region. REG Ialpha protein may have a pathophysiological role as a biological mediator for immune cell-derived IL-22 in the UC mucosa.

The reg4 gene, amplified in the early stages of pancreatic cancer development, is a promising therapeutic target

BACKGROUND

The aim of our work was to identify the genes specifically altered in pancreatic adenocarcinoma and especially those that are altered early in cancer development.

METHODOLOGY/PRINCIPAL FINDINGS

Gene copy number was systematically assessed with an ultra-high resolution CGH oligonucleotide microarray in DNA from samples of pancreatic cancer. Several new cancer-associated variations were observed. In this work we focused on one of them, involving the reg4 gene. Gene copy number gain of the reg4 gene was confirmed by qPCR in 14 cancer samples. It was also found with increased copy number in most PanIN3 samples. The relationship betweena gain in reg4 gene copy number and cancer development was investigated on the human pancreatic cancer cell line Mia-PaCa2 xenografted under the skin of nude mice. When cells were transfected with a vector allowing reg4 expression, they generated tumors almost twice larger in size. In addition, these tumors were more resistant to gemcitabine treatment than control tumors. Interestingly, weekly intraperitoneal administration of a monoclonal antibody to reg4 halved the size of tumors generated by Mia-PaCa2 cells, suggesting that the antibody interfered with a paracrine/autocrine mechanism involving reg4 and stimulating cancer progression. The addition of gemcitabine resulted in further reduction, tumors becoming 5 times smaller than control. Exposure to reg4 antibody resulted in a significant decrease in intra-tumor levels of pAkt, Bcl-xL, Bcl-2, survivin and cyclin D1.

CONCLUSIONS/SIGNIFICANCE

It was concluded that adjuvant therapies targeting reg4 could improve the standard treatment of pancreatic cancer with gemcitabine.

The role of Reg IV gene and its encoding product in gastric carcinogenesis

Although the biologic function of Reg IV is poorly understood, it has been reported that Reg IV is a potent activator of the epidermal growth factor receptor/Akt/AP-1 signaling pathway in colon cancer cells and closely linked with the inhibition of apoptosis. To clarify the role of Reg IV in gastric carcinogenesis and subsequent progression, we examined its expression by immunohistochemistry and in situ hybridization on tissue microarray containing gastric carcinoma, adjacent nonneoplastic mucosa, adenoma, intestinal metaplasia, or gastritis. Gastric carcinoma cell lines (MKN28, AGS, MKN45, KATO-III, and HGC-27) were studied for Reg IV expression by Western blot and reverse transcriptase-polymerase chain reaction followed by sequencing. Frozen samples of gastric carcinoma and adjacent nonneoplastic mucosa were subjected to Western blot, and patient serum, to enzyme-linked immunosorbent assay for Reg IV. Gastric carcinoma cell lines showed different levels of Reg IV mRNA and its encoding protein. The Reg IV protein expression was gradually decreased from intestinal metaplasia, adenoma, and carcinoma to gastritis (P < .05). The positive rate of its mRNA was higher in intestinal metaplasia than carcinoma or nonneoplastic mucosa (P < .05). Elevated serum Reg IV level in gastric carcinoma patients was detected in comparison with that in health individuals (P < .05). Reg IV expression was significantly correlated with the MUC-2 and MUC-5AC expression (P < .05). Among histologic subtypes of the World Health Organization, signet ring cell carcinoma more frequently expressed Reg IV than the others (P < .05), whereas it is the converse for the poorly differentiated group (P < .05). Our study indicated that Reg IV expression experienced up-regulation in gastric intestinal metaplasia and adenoma and then down-regulation with malignant transformation of gastric epithelial cells. It was suggested that Reg IV expression should be considered as a good biomarker for gastric precancerous lesions and was especially related to the histogenic pathway of signet ring cell carcinoma.

Expression profile of REG family proteins REG Ialpha and REG IV in advanced gastric cancer: comparison with mucin phenotype and prognostic markers

Regenerating gene family members 1 (REG Ialpha) and 4 (REG IV) are overexpressed in a subset of gastric cancers. However, comparative characterization of the expression of these family proteins has remained unclear. Therefore, we aimed to elucidate not only the association between REG protein expression and mucin phenotype but also their significance as a prognostic marker for patients with gastric cancer. The expression of REG Ialpha, REG IV, CDX2, MUC2, and MUC5AC in gastric cancer tissues was examined by immunohistochemistry. The relationship between REG protein expression and clinicopathological parameters or mucin phenotype was then analyzed. REG Ialpha and REG IV expression was positive in 33 (52%) and 31 (49%) of 63 gastric cancers examined, respectively. REG Ialpha expression was significantly related to venous invasion and tumor stage, whereas REG IV expression showed no relationship to clinicopathological features. With regard to mucin phenotype, REG IV expression was significantly correlated with MUC2 and CDX2 expression, suggesting an association with the intestinal mucin phenotype of gastric cancer. On the other hand, REG Ialpha expression had no correlation with MUC2, CDX2, or MUC5AC in gastric cancer tissues. Expression of REG Ialpha but not REG IV was an independent predictor of poor outcome in patients with gastric cancer. In addition, patients with gastric cancer negative for both REG Ialpha and REG IV expression had a significantly better outcome than patients positive for either REG Ialpha or REG IV. Profiling of REG protein expression is useful to for prognostication of patients with gastric cancer.