Reg gene family and human diseases

Reduced Expression of REG4 as a Sign of Altered Goblet Cell Function in Necrotizing Enterocolitis

OBJECTIVE

 Defective Goblet cells have been proposed to be involved in necrotizing enterocolitis (NEC). The aim was to study the expression of the Goblet cell marker REG4 and its potential involvement in NEC in preterm infants with and without NEC.

STUDY DESIGN

 Seventy histologically intact intestinal biopsies were studied: 43 were collected during surgery due to NEC (NEC group: 26.5 ± 3.0 weeks' gestational age [wGA]), and 27 from individuals who underwent surgery due to other conditions (Control group; 36.1 ± 4.5 wGA). The tissue samples were immunohistochemically stained for REG4. REG4 expression was quantified with a semiautomated digital image analysis and with clinical data compared between the groups.

RESULTS

 REG4 expression was lower in the NEC group than in the Control group (p = 0.035). Low REG4 expression correlated to the risk of NEC (p = 0.023). In a multivariable logistic regression analysis including GA and REG4 expression for NEC risk, only GA (p < 0.001) and not REG4 expression (p = 0.206) was associated with NEC risk.

CONCLUSION

 This study concludes that Goblet cell dysfunction may be involved in NEC development, as low expression of the Goblet cell marker REG4 was related to an increased NEC risk in preterm infants. Maturity could however not be excluded as a potential confounder for REG4 expression.

KEY POINTS

· REG4 is a specific Goblet cell marker not yet studied in NEC.. · REG4 was quantified in intestinal biopsies from infants with and without NEC.. · REG4 expression was lower in infants with NEC, and expression seems to be maturity dependent..

Serum biomarkers REG1A and REG3A combined with the traditional CEA represent a novel nomogram for the screening and risk stratification of colorectal cancer

BACKGROUND

To develop and validate a serum protein nomogram for colorectal cancer (CRC) screening.

METHODS

The serum protein characteristics were extracted from an independent sample containing 30 colorectal cancer and 12 polyp tissues along with their paired samples, and different serum protein expression profiles were validated using RNA microarrays. The prediction model was developed in a training cohort that included 1345 patients clinicopathologically confirmed CRC and 518 normal participants, and data were gathered from November 2011 to January 2017. The lasso logistic regression model was employed for features selection and serum nomogram building. An internal validation cohort containing 576 CRC patients and 222 normal participants was assessed.

RESULTS

Serum signatures containing 27 secreted proteins were significantly differentially expressed in polyps and CRC compared to paired normal tissue, and REG family proteins were selected as potential predictors. The C-index of the nomogram1 (based on Lasso logistic regression model) which contains REG1A, REG3A, CEA and age was 0.913 (95% CI, 0.899 to 0.928) and was well calibrated. Addition of CA199 to the nomogram failed to show incremental prognostic value, as shown in nomogram2 (based on logistic regression model). Application of the nomogram1 in the independent validation cohort had similar discrimination (C-index, 0.912 [95% CI, 0.890 to 0.934]) and good calibration. The decision curve (DCA) and clinical impact curve (ICI) analysis demonstrated that nomogram1 was clinically useful.

CONCLUSIONS

This study presents a serum nomogram that included REG1A, REG3A, CEA and age, which can be convenient for screening of colorectal cancer.

Immune cell-intrinsic Ah receptor facilitates the expression of antimicrobial REG3G in the small intestine

The intestinal epithelial layer is susceptible to damage by chemical, physiological and mechanical stress. While it is essential to maintain the integrity of epithelium, the biochemical pathways that contribute to the barrier function have not been completely investigated. Here we demonstrate an aryl hydrocarbon receptor (AHR)-dependent mechanism facilitating the production of the antimicrobial peptide AMP regenerating islet-derived protein 3 gamma (REG3G), which is essential for intestinal homeostasis. Genetic ablation of AHR in mice impairs pSTAT3-mediated REG3G expression and increases bacterial numbers of Segmented filamentous bacteria (SFB) and Akkermansia muciniphila in the small intestine. Studies with tissue-specific conditional knockout mice revealed that the presence of AHR in the epithelial cells of the small intestine is not required for the production of REG3G through the phosphorylated STAT3-mediated pathway. However, immune-cell-specific AHR activity is necessary for normal expression of REG3G in all regions of the small intestine. A diet rich in broccoli, capable of inducing AHR activity, increases REG3G production when compared to a semi-purified diet that is devoid of ligands that can potentially activate the AHR, thus highlighting the importance of AHR in antimicrobial function. Overall, these data suggest that homeostatic antimicrobial REG3G production is increased by an AHR pathway intrinsic to the immune cells in the small intestine.

Mutated lncRNA increase the risk of type 2 diabetes by promoting β cell dysfunction and insulin resistance

Islet β cell dysfunction and insulin resistance are the main pathogenesis of type 2 diabetes (T2D), but the mechanism remains unclear. Here we identify a rs3819316 C > T mutation in lncRNA Reg1cp mainly expressed in islets associated with an increased risk of T2D. Analyses in 16,113 Chinese adults reveal that Mut-Reg1cp individuals had higher incidence of T2D and presented impaired insulin secretion as well as increased insulin resistance. Mice with islet β cell specific Mut-Reg1cp knock-in have more severe β cell dysfunction and insulin resistance. Mass spectrometry assay of proteins after RNA pulldown demonstrate that Mut-Reg1cp directly binds to polypyrimidine tract binding protein 1 (PTBP1), further immunofluorescence staining, western blot analysis, qPCR analysis and glucose stimulated insulin secretion test reveal that Mut-Reg1cp disrupts the stabilization of insulin mRNA by inhibiting the phosphorylation of PTBP1 in β cells. Furthermore, islet derived exosomes transfer Mut-Reg1cp into peripheral tissue, which then promote insulin resistance by inhibiting AdipoR1 translation and adiponectin signaling. Our findings identify a novel mutation in lncRNA involved in the pathogenesis of T2D, and reveal a new mechanism for the development of T2D.

Vitamin B12 Regulates the Transcriptional, Metabolic, and Epigenetic Programing in Human Ileal Epithelial Cells

Vitamin B12 (VB12) is a micronutrient that is essential for DNA synthesis and cellular energy production. We recently demonstrated that VB12 oral supplementation coordinates ileal epithelial cells (iECs) and gut microbiota functions to resist pathogen colonization in mice, but it remains unclear whether VB12 directly modulates the cellular homeostasis of iECs derived from humans. Here, we integrated transcriptomic, metabolomic, and epigenomic analyses to identify VB12-dependent molecular and metabolic pathways in human iEC microtissue cultures. RNA sequencing (RNA-seq) revealed that VB12 notably activated genes involved in fatty acid metabolism and epithelial cell proliferation while suppressing inflammatory responses in human iECs. Untargeted metabolite profiling demonstrated that VB12 facilitated the biosynthesis of amino acids and methyl groups, particularly S-adenosylmethionine (SAM), and supported the function of the mitochondrial carnitine shuttle and TCA cycle. Further, genome-wide DNA methylation analysis illuminated a critical role of VB12 in sustaining cellular methylation programs, leading to differential CpG methylation of genes associated with intestinal barrier function and cell proliferation. Together, these findings suggest an essential involvement of VB12 in directing the fatty acid and mitochondrial metabolisms and reconfiguring the epigenome of human iECs to potentially support cellular oxygen utilization and cell proliferation.

Identification of diagnostic signatures in ulcerative colitis patients via bioinformatic analysis integrated with machine learning

Ulcerative colitis (UC) is an immune-related disorder with enhanced prevalence globally. Early diagnosis is critical for the effective treatment of UC. However, it still lacks specific diagnostic signatures. The aim of our study was to explore efficient signatures and construct the diagnostic model for UC. Microarray data of GSE87473 and GSE48634, which were obtained from tissue biopsy samples, were downloaded from the Gene Expression Omnibus (GEO), and differently expressed genes (DEGs), GO, and KEGG analyses were performed. We constructed the PPI network via STRING database. The immune infiltration of the samples was evaluated using CIBERSORT methods combined with the LM22 feature matrix. The logistic regression model was constructed, with the expression of selected genes as the predictor variable, and the UC occurrence as the responsive variable. As a result, a total of 126 DEGs between the UC patients and normal counterparts were identified. The GO and KEGG analysis revealed that multiple biological processes, such as antimicrobial humoral immune response mediated by antimicrobial peptide and IL-17 signaling pathway, were enriched. The infiltration of eight immune cell types (B cells naive, Dendritic.cells.activated, Macrophages.M0, Macrophages.M2, Mast.cells.resting, Neutrophils, Plasma.cells, and T.cells.follicular.helper) was significantly different between patients with UC and normal counterparts. The top 50 most significant DEGs were selected for the construction of the PPI network. The average AUC of the logistic regression model in the fivefold cross-validation was 0.8497 in the training set, GSE87473. The AUC of another independent verification set of GSE48634 from the GEO database was 0.7208. In conclusion, we identified potential hub genes, including REG3A, REG1A, DEFA6, REG1B, and DEFA5, which might be significantly associated with UC progression. The logistic regression model based on the five genes could reliably diagnose UC patients.

The regenerating protein 3A: a crucial molecular with dual roles in cancer

Introduction

REG3A, a member of the third subclass of the Reg family, has been found in a variety of tissues but is not detected in immune cells. In the past decade, it has been determined that REG3A expression is regulated by injury, infection, inflammatory stimuli, and pro-cytokines via different signaling pathways, and it acts as a tissue-repair, bactericidal, and anti-inflammatory molecule in human diseases. Recently, the role of REG3A in cancer has received increasing attention. The present article aims to investigate the structure, expression, regulation, function of REG3A, and to highlight the potential role of REG3A in tumors.

Methods

A detailed literature search and data organization were conducted to find information about the role of REG3A in variety of physiological functions and tumors.

Results

Contradictory roles of REG3A have been reported in different tumor models. Some studies have demonstrated that high expression of REG3A in cancers can be oncogenic. Other studies have shown decreased REG3A expression in cancer cells as well as suppressed tumor growth.

Conclusions

Taken together, better understanding of REG3A may lead to new insights that make it a potentially useful target for cancer therapy.

Gastric Cancer: Identification of microRNAs Inhibiting Druggable Targets and Mediating Efficacy in Preclinical In Vivo Models

In addition to chemotherapy, targeted therapies have been approved for treatment of locally advanced and metastatic gastric cancer. The therapeutic benefit is significant but more durable responses and improvement of survival should be achieved. Therefore, the identification of new targets and new approaches for clinical treatment are of paramount importance. In this review, we searched the literature for down-regulated microRNAs which interfere with druggable targets and exhibit efficacy in preclinical in vivo efficacy models. As druggable targets, we selected transmembrane receptors, secreted factors and enzymes. We identified 38 microRNAs corresponding to the criteria as outlined. A total of 13 miRs target transmembrane receptors, nine inhibit secreted proteins and 16 attenuate enzymes. These microRNAs are targets for reconstitution therapy of gastric cancer. Further target validation experiments are mandatory for all of the identified microRNAs.

A four-genes based diagnostic signature for osteoarthritis

Osteoarthritis (OA) is a primary leading cause of pain and disability. However, some cases are diagnosed at the later stage which delayed the timely treatment. This study aims to identify effective diagnostic signature for OA. The mRNA profile GSE48566 including 106 blood samples of OA patients and 33 blood samples of healthy individuals was downloaded from Gene Expression Omnibus (GEO) database. The potential OA-related genes were screened by weighted gene co-expression network analysis (WGCNA). Gene ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to reveal the functions or pathways of OA-related genes using the clusterProfiler function package of R software. Key genes significantly involved in OA progression were further screened by protein-protein interaction (PPI) network. The logistic regression model and the random forest model were conducted by bringing into optimal genes selected by stepwise regression analysis, and fivefold cross validation method was used to determine their reliability. A total of 146 genes, existed in three modules and might be associated with the occurrence of OA, were screened. 15 genes were screened from the PPI network and four genes, including CCR6, CLEC7A, IL18 and SRSF2, were further optimized. Finally, a logistic regression model and a random forest model were conducted by bringing into four optimal genes, and could reliably separate OA patients from healthy subjects. Our study established two effective diagnostic models based on CCR6, CLEC7A, IL18 and SRSF2, which could reliably separate OA patients from healthy subjects.

A combination of urinary biomarker panel and PancRISK score for earlier detection of pancreatic cancer: A case-control study

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, with around 9% of patients surviving >5 years. Asymptomatic in its initial stages, PDAC is mostly diagnosed late, when already a locally advanced or metastatic disease, as there are no useful biomarkers for detection in its early stages, when surgery can be curative. We have previously described a promising biomarker panel (LYVE1, REG1A, and TFF1) for earlier detection of PDAC in urine. Here, we aimed to establish the accuracy of an improved panel, including REG1B instead of REG1A, and an algorithm for data interpretation, the PancRISK score, in additional retrospectively collected urine specimens. We also assessed the complementarity of this panel with CA19-9 and explored the daily variation and stability of the biomarkers and their performance in common urinary tract cancers.

METHODS AND FINDINGS

Clinical specimens were obtained from multiple centres: Barts Pancreas Tissue Bank, University College London, University of Liverpool, Spanish National Cancer Research Center, Cambridge University Hospital, and University of Belgrade. The biomarker panel was assayed on 590 urine specimens: 183 control samples, 208 benign hepatobiliary disease samples (of which 119 were chronic pancreatitis), and 199 PDAC samples (102 stage I-II and 97 stage III-IV); 50.7% were from female individuals. PDAC samples were collected from patients before treatment. The samples were assayed using commercially available ELISAs. Statistical analyses were performed using non-parametric Kruskal-Wallis tests adjusted for multiple comparisons, and multiple logistic regression. Training and validation datasets for controls and PDAC samples were obtained after random division of the whole available dataset in a 1:1 ratio. The substitution of REG1A with REG1B enhanced the performance of the panel to detect resectable PDAC. In a comparison of controls and PDAC stage I-II samples, the areas under the receiver operating characteristic curve (AUCs) increased from 0.900 (95% CI 0.843-0.957) and 0.926 (95% CI 0.843-1.000) in the training (50% of the dataset) and validation sets, respectively, to 0.936 in both the training (95% CI 0.903-0.969) and the validation (95% CI 0.888-0.984) datasets for the new panel including REG1B. This improved panel showed both sensitivity (SN) and specificity (SP) to be >85%. Plasma CA19-9 enhanced the performance of this panel in discriminating PDAC I-II patients from controls, with AUC = 0.992 (95% CI 0.983-1.000), SN = 0.963 (95% CI 0.913-1.000), and SP = 0.967 (95% CI 0.924-1.000). We demonstrate that the biomarkers do not show significant daily variation, and that they are stable for up to 5 days at room temperature. The main limitation of our study is the low number of stage I-IIA PDAC samples (n = 27) and lack of samples from individuals with hereditary predisposition to PDAC, for which specimens collected from control individuals were used as a proxy.

CONCLUSIONS

We have successfully validated our urinary biomarker panel, which was improved by substituting REG1A with REG1B. At a pre-selected cutoff of >80% SN and SP for the affiliated PancRISK score, we demonstrate a clinically applicable risk stratification tool with a binary output for risk of developing PDAC ('elevated' or 'normal'). PancRISK provides a step towards precision surveillance for PDAC patients, which we will test in a prospective clinical study, UroPanc.

Reg-1α Promotes Differentiation of Cortical Progenitors via Its N-Terminal Active Domain

Reg-1α belongs to the Reg family of small, secreted proteins expressed in both pancreas and nervous system. Reg-1α is composed of two domains, an insoluble C-type lectin domain and a short soluble N-terminal peptide, which is released from the molecule upon proteolytic N-terminal processing, although the biological significance of this proteolysis remains unclear. We have previously shown that binding of Reg-1α to its receptor Extl3 stimulates axonal outgrowth. Reg-1α and Extl3 genes are expressed in the developing cortex but their expression decreases in adulthood, pointing to a possible function of this signaling system at the early developmental stages. Here, we demonstrate that recombinant Reg-1α increases migration and differentiation of cultured embryonic rat telencephalic progenitors via the activation of GSK-3β activity. In vivo overexpression of Reg-1α by in utero electroporation, has a similar effect, favoring premature differentiation of cortical progenitors. Notably, the N-terminal soluble domain, but not the C-type lectin domain, is largely responsible for Reg-1α effects on cortical neuronal differentiation. We thus conclude that Reg-1α via its proteolytically generated N-terminal domain is required for basic development processes.

Synthesis and Screening of Novel Peptides on Human Pancreatic Islets for Type 1 Diabetes Therapies. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020;2020:2217-2220. [PMID: 33018448 DOI: 10.1109/embc44109.2020.9175493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Type 1 diabetic patients characteristically exhibit a loss of insulin production, leading to chronic hyperglycemia and related complications. Herein we describe the design, synthesis and screening of novel oligopeptides for their potential to enhance the secretion of insulin from human pancreatic islets. The investigation of these compounds, based off the patented INGAP-PP sequence, aims to identify the peptide features key to maximizing insulin secretion.Clinical Relevance - This report describes the relative efficacy of selected novel compounds for potential Type 1 Diabetes Therapy. Tested on live human pancreatic islets, the compounds are evaluated for their enhancing/inhibitory effect on the secretion of insulin. These studies pave the way for future targeted drug therapies.

Reg3α and Reg3β Expressions Followed by JAK2/STAT3 Activation Play a Pivotal Role in the Acceleration of Liver Hypertrophy in a Rat ALPPS Model

To explore the underlying mechanism of rapid liver hypertrophy by liver partition in associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), liver partition at different sites was investigated. Increased inflammatory cytokines owing to the liver partition have been reportedly responsible. If this were true, rapid liver hypertrophy should be achieved regardless of where the liver was split. A male Sprague-Dawley rat model was created, in which a liver split was placed inside the portal vein ligated lobe (PiLL), in addition to the ALPPS and portal vein ligation (PVL) models. Liver regeneration rate, inflammatory cytokine levels, activation status of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and expressions of regenerating islet-derived (Reg)3α and Reg3β were investigated. The liver regeneration rate was significantly higher in the ALPPS group than in the PiLL group, whereas inflammatory cytokine levels were nearly equal. Additional volume increase in ALPPS group over PVL and PiLL groups was JAK2/STAT3-dependent. Reg3α and Reg3β expressions were observed only in the ALPPS group. An increase in inflammatory cytokines was not enough to describe the mechanism of rapid liver hypertrophy in ALPPS. Expressions of Reg3α and Reg3β could play an important role in conjunction with an activation of the JAK2/STAT3 pathway.

Regenerating islet-derived protein (Reg)3β plays a crucial role in attenuation of ileitis and colitis in mice

Regenerating islet-derived protein (Reg)3β belongs to a member of the Reg family of proteins and has pleiotropic functions, including antimicrobial activity and tissue repair. However, whether Reg3β plays a protective role in the development of colitis and ileitis has not been fully investigated. We generated transgenic mice expressing a short form of cellular FLICE-inhibitory protein (cFLIPs) that promotes necroptosis, a regulated form of cell death. cFLIPs transgenic (CFLARs Tg) mice develop severe ileitis in utero. Although Reg3β is undetectable in the small intestine of wild-type embryos, its expression is aberrantly elevated in the small intestine of CFLARs Tg embryos. To test whether elevated Reg3β attenuates or exacerbates ileitis in CFLARs Tg mice, we generated a Reg3b^−/− strain. Reg3b^−/− mice grew to adulthood without apparent abnormalities. Deletion of Reg3b in CFLARs Tg mice exacerbated the embryonic lethality of CFLARs Tg mice. Dextran sulfate sodium-induced colitis, characterized by body weight loss and infiltration of neutrophils, was exacerbated in Reg3b^−/− compared to wild-type mice. Moreover, the expression of Interleukin 6, an inflammatory cytokine and Chitinase-like 3, a marker for tissue repair macrophages was elevated in the colon of Reg3b^−/− mice compared to wild-type mice after DSS treatment. Together, these results suggest that attenuation of colitis and ileitis is a result of Reg3β′s real function.

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The expression of Reg3β is elevated in the embryonic small intestine of CFLARs Tg mice.

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Reg3b^−/− mice grow to adulthood without apparent abnormalities.

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Dextran sulfate sodium-induced colitis is exacerbated in Reg3b^−/− mice.

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Deletion of Reg3b exacerbates ileitis in CFLARs Tg mice.

LncRNA REG1CP promotes tumorigenesis through an enhancer complex to recruit FANCJ helicase for REG3A transcription

Protein products of the regenerating islet-derived (REG) gene family are important regulators of many cellular processes. Here we functionally characterise a non-protein coding product of the family, the long noncoding RNA (lncRNA) REG1CP that is transcribed from a DNA fragment at the family locus previously thought to be a pseudogene. REG1CP forms an RNA–DNA triplex with a homopurine stretch at the distal promoter of the REG3A gene, through which the DNA helicase FANCJ is tethered to the core promoter of REG3A where it unwinds double stranded DNA and facilitates a permissive state for glucocorticoid receptor α (GRα)-mediated REG3A transcription. As such, REG1CP promotes cancer cell proliferation and tumorigenicity and its upregulation is associated with poor outcome of patients. REG1CP is also transcriptionally inducible by GRα, indicative of feedforward regulation. These results reveal the function and regulation of REG1CP and suggest that REG1CP may constitute a target for cancer treatment.

The regenerating islet-derived (REG) protein family suppresses cell death and promotes cell proliferation. Here the authors report that the lncRNA REG1CP forms an RNA–DNA triplex at the promoter of REG3A gene to increase its expression.

Association of regenerating gene 1A single-nucleotide polymorphisms and nasopharyngeal carcinoma susceptibility in southern Chinese population

Objective

Nasopharyngeal carcinoma (NPC) is a common malignancy in Southern China and Southeast Asia. Genetic susceptibility is a major contributing factor in determining the individual risk of NPC in these areas. To test the association between NPC and variants in regenerating gene 1A (REG1A), we conducted a hospital-based case–control study in a Cantonese-speaking population from Guangdong province.

Methods

We endeavored to determine whether genetic variants of the REG1A gene were associated with the risk of NPC amidst the Cantonese population in a hospital-based case–control study using polymerase chain reaction-restriction and direct sequencing analysis in 211 NPC patients and 150 healthy controls. The association between NPC risk and the 14C/T, 20C/T, 369G/T, 1201A/G, and 2922C/T polymorphisms was examined after adjustment for age and sex.

Results

We found an increased risk of developing NPC in individuals with REG1A 2922C/T variant genotype (p = 0.003, OR 0.419, 95% CI 0.235–0.746), and after adjustment for sex and age (p = 0.003, OR 0.406, 95% CI 0.226–0.732). No association between other polymorphisms (14C/T, 20C/T, 369G/T, and 1201A/G) and the risk of NPC was observed, before or after adjustment for age and sex.

Conclusion

Our findings suggest that the REG1A 2922C/T polymorphism is associated with an increased risk of developing NPC in a Cantonese population from Guangdong province. Larger studies are required to confirm our findings and unravel the underlying mechanisms.

Electronic supplementary material

The online version of this article (10.1007/s00405-019-05645-9) contains supplementary material, which is available to authorized users.

REG4 is an indicator for KRAS mutant lung adenocarcinoma with TTF-1 low expression

OBJECTIVES

Recent research has classified lung adenocarcinoma patients with KRAS mutation into three subtypes by co-occurring genetic events in TP53 (KP subgroup), STK11/LKB1 (KL subgroup) and CDKN2A/B inactivation plus TTF-1 low expression (KC subgroup). The aim of this study was to identify valuable biomarkers by searching the candidate molecules that contribute to lung adenocarcinoma pathogenesis, especially KC subtype.

MATERIALS AND METHODS

We analyzed the publicly available database and identified the candidate REG4 using the E-GEOD-31210 dataset, and then confirmed by TCGA dataset. In addition, an independent cohort of 55 clinical samples was analyzed by quantitative real-time PCR analysis. Functional studies and RNA sequencing were performed after silencing the REG4 expression.

RESULTS

REG4, an important regulator of gastro-intestinal carcinogenesis, was highly expressed in KRAS mutant lung adenocarcinoma with low expression of TTF-1 (KC subtype). The results were validated both by gene expression analysis and immunohistochemistry study in an independent 55 clinical samples from Fudan University Shanghai Cancer Center. Further in vitro and in vivo functional assays revealed silencing REG4 expression significantly reduces cancer cell proliferation and tumorigenesis. Moreover, RNA sequencing and GSEA analysis displayed that REG4 knockdown might induce cell cycle arrest by regulating G2/M checkpoint and E2F targets.

CONCLUSION

Our results indicate that REG4 plays an important role in KRAS-driven lung cancer pathogenesis and is a novel biomarker of lung adenocarcinoma subtype. Future studies are required to clarify the underlying mechanisms of REG4 in the division and proliferation of KC tumors and its potential therapeutic value.

Krüppel-like factor 3 inhibition by mutated lncRNA Reg1cp results in human high bone mass syndrome

The authors report a mutation in the long noncoding RNA Reg1cp that induces osteogenesis via vascular induction in humans. This mutation affects angiogenesis by blocking Klf3’s repressing activity. The Klf3 antagonist Ophiopogonin D could promote CD31^hiEmcn^hi vessel formation and osteogenesis in osteoporosis mice.

High bone mass (HBM) is usually caused by gene mutations, and its mechanism remains unclear. In the present study, we identified a novel mutation in the long noncoding RNA Reg1cp that is associated with HBM. Subsequent analysis in 1,465 Chinese subjects revealed that heterozygous Reg1cp individuals had higher bone density compared with subjects with WT Reg1cp. Mutant Reg1cp increased the formation of the CD31^hiEmcn^hi endothelium in the bone marrow, which stimulated angiogenesis during osteogenesis. Mechanistically, mutant Reg1cp directly binds to Krüppel-like factor 3 (KLF3) to inhibit its activity. Mice depleted of Klf3 in endothelial cells showed a high abundance of CD31^hiEmcn^hi vessels and increased bone mass. Notably, we identified a natural compound, Ophiopogonin D, which functions as a KLF3 inhibitor. Administration of Ophiopogonin D increased the abundance of CD31^hiEmcn^hi vessels and bone formation. Our findings revealed a specific mutation in lncRNA Reg1cp that is involved in the pathogenesis of HBM and provides a new target to treat osteoporosis.

Regenerating islet-derived 1α (REG-1α) protein increases tau phosphorylation in cell and animal models of tauopathies

REG-1α, a secreted protein containing a C-type lectin domain, is expressed in various organs and plays different roles in digestive system cells in physiological and pathological conditions. Like other members of the Reg family, REG-1α is expressed also in the brain where it has different functions. For instance, we previously reported that REG-1α regulates neurite outgrowth and is overexpressed during the very early stages of Alzheimer's disease (AD). However, REG-1α function in neural cells during neural degeneration remains unknown. First, REG-1α and phosphorylated tau expression were assessed in tissue sections from the hippocampus, representing neurofibrillary tangles (NFTs), from patients with AD, and from basal ganglia, representing subcortical NFTs, from patients with progressive supranuclear palsy (PSP). We found an association between REG-1α expression, tau hyperphosphorylation and NFTs in human brain samples from patients with these neurodegenerative diseases. Then, the effects of REG-1α overexpression on tau phosphorylation and axonal morphology were investigated i) in primary cultures of rat neurons that express human tau P301L and ii) in a transgenic zebrafish model of tauopathy that expresses human tau P301L. In the tau P301L cell model, REG-1α overexpression increased tau phosphorylation at the S202/T205 and S396 residues (early and late stages of abnormal phosphorylation, respectively) through the AKT/GSK3-β pathway. This effect was associated with axonal defects both in tau P301L-expressing rat neurons and zebrafish embryos. Our findings suggest a functional role for REG-1α during tauopathy development and progression and, specifically, its involvement in the modification of tau phosphorylation temporal sequence.

Glycoprotein biomarkers for the detection of pancreatic ductal adenocarcinoma

Pancreatic cancer (PaC) shows a clear tendency to increase in the next years and therefore represents an important health and social challenge. Currently, there is an important need to find biomarkers for PaC early detection because the existing ones are not useful for that purpose. Recent studies have indicated that there is a large window of time for PaC early detection, which opens the possibility to find early biomarkers that could greatly improve the dismal prognosis of this tumor. The present manuscript reviews the state of the art of the existing PaC biomarkers. It focuses on the anomalous glycosylation process and its role in PaC. Glycan structures of glycoconjugates such as glycoproteins are modified in tumors and these modifications can be detected in biological fluids of the cancer patients. Several studies have found serum glycoproteins with altered glycan chains in PaC patients, but they have not shown enough specificity for PaC. To find more specific cancer glycoproteins we propose to analyze the glycan moieties of a battery of glycoproteins that have been reported to increase in PaC tissues and that can also be found in serum. The combination of these new candidate glycoproteins with their aberrant glycosylation together with the existing biomarkers could result in a panel, which would expect to give better results as a new tool for early diagnosis of PaC and to monitor the disease.

Significance of Interleukin-6/STAT Pathway for the Gene Expression of REG Iα, a New Autoantigen in Sjögren's Syndrome Patients, in Salivary Duct Epithelial Cells

The regenerating gene, Reg, was originally isolated from a rat regenerating islet complementary DNA (cDNA) library, and its human homologue was named REG Iα. Recently, we reported that REG Iα messenger RNA (mRNA), as well as its product, was overexpressed in ductal epithelial cells in the salivary glands of Sjögren's syndrome patients. Furthermore, autoantibodies against REG Iα were found in the sera of Sjögren's syndrome patients, and the patients who were positive for the anti-REG Iα antibody showed significantly lower saliva secretion than antibody-negative patients. We found the mechanism of REG Iα induction in salivary ductal epithelial cells. Reporter plasmid containing REG Iα promoter (-1190/+26) upstream of a luciferase gene was introduced into human NS-SV-DC and rat A5 salivary ductal cells. The cells were treated with several cytokines (interleukin (IL)-6, IL-8, etc.), upregulated in Sjögren's syndrome salivary ducts, and the transcriptional activity was measured. IL-6 stimulation significantly enhanced the REG Iα promoter activity in both cells. Deletion analysis revealed that the -141∼-117 region of the REG Iα gene was responsible for the promoter activation by IL-6, which contains a consensus sequence for signal transducer and activator of transcription (STAT) binding. The introduction of small interfering RNA for human STAT3 abolished IL-6-induced REG Iα transcription. These results indicated that IL-6 stimulation induced REG Iα transcription through STAT3 activation and binding to the REG Iα promoter in salivary ductal cells. This dependence of REG Iα induction upon IL-6/STAT in salivary duct epithelial cells may play an important role in the pathogenesis/progression of Sjögren's syndrome.

Prognostic impact of a novel gene expression profile classifier for the discrimination between metastatic and non-metastatic primary colorectal cancer tumors

Despite significant advances have been achieved in the genetic characterization of sporadic colorectal cancer (sCRC), the precise genetic events leading to the development of distant metastasis remain poorly understood. Thus, accurate prediction of metastatic disease in newly-diagnosed sCRC patients remains a challenge. Here, we evaluated the specific genes and molecular pathways associated with the invasive potential of colorectal tumor cells, through the assessment of the gene expression profile (GEP) of coding and non-coding genes in metastatic (MTX) vs. non-metastatic (non-MTX) primary sCRC tumors followed for >5 years. Overall, MTX tumors showed up-regulation of genes associated with tumor progression and metastatic potential while non-MTX cases displayed GEP associated with higher cell proliferation, activation of DNA repair and anti-tumoral immune/inflammatory responses. Based on only 19 genes a specific GEP that classifies sCRC tumors into two MTX-like and non-MTX-like molecular subgroups was defined which shows an independent prognostic impact on patient overall survival, particularly when it is combined with the lymph node status at diagnosis. In summary, we show an association between the global GEP of primary sCRC cells and their metastatic potential and defined a GEP-based classifier that provides the basis for further prognostic stratification of sCRC patients who are at risk of distant metastases.

Reg Gene Expression in Periosteum after Fracture and Its In Vitro Induction Triggered by IL-6

The periosteum is a thin membrane that surrounds the outer surface of bones and participates in fracture healing. However, the molecular signals that trigger/initiate the periosteal reaction are not well established. We fractured the rat femoral bone at the diaphysis and fixed it with an intramedullary inserted wire, and the expression of regenerating gene (Reg) I, which encodes a tissue regeneration/growth factor, was analyzed. Neither bone/marrow nor muscle showed RegI gene expression before or after the fracture. By contrast, the periosteum showed an elevated expression after the fracture, thereby confirming the localization of Reg I expression exclusively in the periosteum around the fractured areas. Expression of the Reg family increased after the fracture, followed by a decrease to basal levels by six weeks, when the fracture had almost healed. In vitro cultures of periosteal cells showed no Reg I expression, but the addition of IL-6 significantly induced Reg I gene expression. The addition of IL-6 also increased the cell number and reduced pro-apoptotic gene expression of Bim. The increased cell proliferation and reduction in Bim gene expression were abolished by transfection with Reg I siRNA, indicating that these IL-6-dependent effects require the Reg I gene expression. These results indicate the involvement of the IL-6/Reg pathway in the osteogenic response of the periosteum, which leads to fracture repair.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Recognition of microbial glycans by soluble human lectins

Human innate immune lectins that recognize microbial glycans can conduct microbial surveillance and thereby help prevent infection. Structural analysis of soluble lectins has provided invaluable insight into how these proteins recognize their cognate carbohydrate ligands and how this recognition gives rise to biological function. In this opinion, we cover the structural features of lectins that allow them to mediate microbial recognition, highlighting examples from the collectin, Reg protein, galectin, pentraxin, ficolin and intelectin families. These analyses reveal how some lectins (e.g., human intelectin-1) can recognize glycan epitopes that are remarkably diverse, yet still differentiate between mammalian and microbial glycans. We additionally discuss strategies to identify lectins that recognize microbial glycans and highlight tools that facilitate these discovery efforts.

Effect of resveratrol on cancer progression through the REG Ⅲ expression pathway in head and neck cancer cells

Identification of reliable markers of chemo- and radiosensitivity and the key molecules that enhance the susceptibility of head and neck squamous cell carcinoma (HNSCC) to anticancer treatments is highly desirable. Previously, we have reported that regenerating gene (REG) Ⅲ expression was such a marker associated with an improved survival rate for HNSCC patients. In the present study, we investigated the stimulators for induction of REG Ⅲ expression using REG Ⅲ promoter assay in HNSCC cells transfected with REG Ⅲ promoter vector. We tested inflammatory cytokines, growth factors, polyphenols, PPARγ activator of thiazolidinediones, and histone deacetylase inhibitors, and found that 3,4',5-trihydroxy-trans-stilbene (resveratrol) significantly increased the REG Ⅲ promoter activity and the mRNA levels of REG Ⅲ in HNSCC cells. Moreover, we demonstrated the effect of resveratrol on cancer cell progression, such as cell proliferation, chemo‑ and radiosensitivity and cancer invasion of HNSCC cells. Resveratrol significantly inhibited cell growth, enhanced chemo‑ and radiosensitivity, and blocked cancer invasion of HNSCC cells. These data suggested that resveratrol could inhibit cancer progression through the REG Ⅲ expression pathway in HNSCC cells.

Prognostic role of regenerating gene-I in patients with stage-IV head and neck squamous cell carcinoma

Background

Regenerating gene (REG) family is composed of antiapoptotic factors and growth factors that affect epithelial cells within the digestive system. Regenerating gene-I has been studied in different cancers. However, it has never been studied in head and neck cancer. We investigated the expression of REG-I in head and neck SCC and its relevance to patient survival rates.

Methods

Untreated biopsy specimens of 60 patients with stage IV head and neck SCC were collected, and the expression of REG-I was evaluated using immunohistochemistry. The association between REG-I expression and clinico-pathological features or survival status of the patients was assessed by Chi-square test, Fisher’s exact test and Kaplan-Meier method. Cox proportional hazard model was used to identify the independent prognostic factors.

Results

Incidence of lymphatic permeation, vascular invasion and pathological lymph nodes was significantly higher in REG-I negative group (p = 0.008, 0.030 and 0.015, respectively). Overall and cancer-free survival rates were significantly higher in REG-I positive group (p = 0.000434 and 1.0847E-8, respectively). Univariate analysis showed that REG-I was an independent prognostic factor for predicting long-term overall survival (p = 0.002), and multivariate analysis showed that REG-I and lymphatic permeation were independent prognostic factors for predicting long-term disease-free survival (p = 0.001 and 0.022, respectively).

Conclusion

Our results showed for the first time that, REG-I is expressed in head and neck SCC. REG-I expression is associated with a longer survival status. We conclude that, REG-I might be a prognostic marker in head and neck SSC and should be further investigated.

REG4 Is Highly Expressed in Mucinous Ovarian Cancer: A Potential Novel Serum Biomarker

Preoperative diagnostics of ovarian neoplasms rely on ultrasound imaging and the serum biomarkers CA125 and HE4. However, these markers may be elevated in non-neoplastic conditions and may fail to identify most non-serous epithelial cancer subtypes. The objective of this study was to identify histotype-specific serum biomarkers for mucinous ovarian cancer. The candidate genes with mucinous histotype specific expression profile were identified from publicly available gene-expression databases and further in silico data mining was performed utilizing the MediSapiens database. Candidate biomarker validation was done using qRT-PCR, western blotting and immunohistochemical staining of tumor tissue microarrays. The expression level of the candidate gene in serum was compared to the serum CA125 and HE4 levels in a patient cohort of prospectively collected advanced ovarian cancer. Database searches identified REG4 as a potential biomarker with specificity for the mucinous ovarian cancer subtype. The specific expression within epithelial ovarian tumors was further confirmed by mRNA analysis. Immunohistochemical staining of ovarian tumor tissue arrays showed distinctive cytoplasmic expression pattern only in mucinous carcinomas and suggested differential expression between benign and malignant mucinous neoplasms. Finally, an ELISA based serum biomarker assay demonstrated increased expression only in patients with mucinous ovarian cancer. This study identifies REG4 as a potential serum biomarker for histotype-specific detection of mucinous ovarian cancer and suggests serum REG4 measurement as a non-invasive diagnostic tool for postoperative follow-up of patients with mucinous ovarian cancer.

Reg3g Promotes Pancreatic Carcinogenesis in a Murine Model of Chronic Pancreatitis

BACKGROUND

Regenerating islet-derived 3 (Reg3) is abnormally expressed in several human digestive system diseases, including chronic pancreatitis (CP) and pancreatic cancer (PC).

AIM

The purpose of this study was to clarify the mechanism of the enhanced expression of Reg3 in inflammation-induced PC.

METHODS

C57BL/6 mice were treated with caerulein for 6 weeks to induce CP and then injected with pReg3g--a lentivirus system encoding for murine Reg3g--accompanied by dimethylbenzanthracene to induce PC. We detected pancreatic histopathological characteristics, tumor-related gene expression, inflammation-associated pathway activation, serum biochemical indicators, and immunological cell activities.

RESULTS

The mice that developed CP after caerulein treatment were marked by pronounced histologic lesions, elevated serum amylase levels, and activation of inflammation-related pathways. Mice given a high dose of pReg3g developed PC by 16 weeks, with recognizable tumors in the pancreas. While, both the low and high doses of pReg3g produced higher transcription of c-fos, k-ras, cytokeratin-19, and proliferating cell nuclear antigen, and a lower expression of caspase-3 compared to pNEG controls. Additionally, the higher dose of pReg3g increased the expressions of pSTAT3, NFκB (p65), and SOCS3 methylation during PC development. In addition, mice treated with pReg3g displayed higher levels of serum IL10 and TGFβ and suppressed T lymphocyte proliferation and DC function.

CONCLUSION

The comprehensive analysis suggests enhanced Reg3g expression exacerbates PC in inflammation-associated cancer progression. Reg3g appears to promote CP-related PC in mice through multiple mechanisms, involving enhanced transcription of pancreatic tumor markers, repression of anti-tumor immunity, and activation of STAT3/p65 signal transduction pathways.

Regenerating islet-derived protein 1 inhibits the activation of islet stellate cells isolated from diabetic mice

Emerging evidence indicates that the islet fibrosis is attributable to activation of islet stellate cells (ISCs). In the present study, we compared the differences in biological activity of ISCs isolated from diabetic db/db and non-diabetic db/m mice, and the effects of the regenerating islet-derived protein 1 (Reg1) on ISC function. We showed that ISCs isolated from db/db mice were activated more rapidly than those from db/m mice during culture. Both Reg1 and its putative receptor exostosin-like glycosyltransferase 3 (EXTL3) were highly expressed by diabetic ISCs. Treatment with Reg1 inhibited migration, viability, and synthesis and secretion of Type I Collagen(Col-I), Type III Collagen(Col-III) and Fibronectin(FN) by diabetic ISCs, and this was associated with deactivation of the PI3K/Akt, MAPK/Erk1/2 signaling pathway in an EXTL3-dependent manner. In conclusion, our observations (i) confirmed the presence of fibrogenic stellate cells within pancreatic islets, which are prone to be activated in Type 2 diabetes, and (ii) revealed a potential role for Reg1 in preventing ISC activation.

mRNAs and Protein Synthetic Machinery Localize into Regenerating Spinal Cord Axons When They Are Provided a Substrate That Supports Growth

Although intra-axonal protein synthesis is well recognized in cultured neurons and during development in vivo, there have been few reports of mRNA localization and/or intra-axonal translation in mature CNS axons. Indeed, previous work indicated that mature CNS axons contain much lower quantities of translational machinery than PNS axons, leading to the conclusion that the capacity for intra-axonal protein synthesis is linked to the intrinsic capacity of a neuron for regeneration, with mature CNS neurons showing much less growth after injury than PNS neurons. However, when regeneration by CNS axons is facilitated, it is not known whether the intra-axonal content of translational machinery changes or whether mRNAs localize into these axons. Here, we have used a peripheral nerve segment grafted into the transected spinal cord of adult rats as a supportive environment for regeneration by ascending spinal axons. By quantitative fluorescent in situ hybridization combined with immunofluorescence to unambiguously distinguish intra-axonal mRNAs, we show that regenerating spinal cord axons contain β-actin, GAP-43, Neuritin, Reg3a, Hamp, and Importin β1 mRNAs. These axons also contain 5S rRNA, phosphorylated S6 ribosomal protein, eIF2α translation factor, and 4EBP1 translation factor inhibitory protein. Different levels of these mRNAs in CNS axons from regenerating PNS axons may relate to differences in the growth capacity of these neurons, although the presence of mRNA transport and likely local translation in both CNS and PNS neurons suggests an active role in the regenerative process.

SIGNIFICANCE STATEMENT

Although peripheral nerve axons retain the capacity to locally synthesize proteins into adulthood, previous studies have argued that mature brain and spinal cord axons cannot synthesize proteins. Protein synthesis in peripheral nerve axons is increased during regeneration, and intra-axonally synthesized proteins have been shown to contribute to nerve regeneration. Here, we show that mRNAs and translational machinery are transported into axons regenerating from the spinal cord into the permissive environment of a peripheral nerve graft. Our data raise the possibility that spinal cord axons may make use of localized protein synthesis for regeneration.

Identification of a Three-Biomarker Panel in Urine for Early Detection of Pancreatic Adenocarcinoma

PURPOSE

Noninvasive biomarkers for early detection of pancreatic ductal adenocarcinoma (PDAC) are currently not available. Here, we aimed to identify a set of urine proteins able to distinguish patients with early-stage PDAC from healthy individuals.

EXPERIMENTAL DESIGN

Proteomes of 18 urine samples from healthy controls, chronic pancreatitis, and patients with PDAC (six/group) were assayed using GeLC/MS/MS analysis. The selected biomarkers were subsequently validated with ELISA assays using multiple logistic regression applied to a training dataset in a multicenter cohort comprising 488 urine samples.

RESULTS

LYVE-1, REG1A, and TFF1 were selected as candidate biomarkers. When comparing PDAC (n = 192) with healthy (n = 87) urine specimens, the resulting areas under the receiver-operating characteristic curves (AUC) of the panel were 0.89 [95% confidence interval (CI), 0.84-0.94] in the training (70% of the data) and 0.92 (95% CI, 0.86-0.98) in the validation (30% of the data) datasets. When comparing PDAC stage I-II (n = 71) with healthy urine specimens, the panel achieved AUCs of 0.90 (95% CI, 0.84-0.96) and 0.93 (95% CI, 0.84-1.00) in the training and validation datasets, respectively. In PDAC stage I-II and healthy samples with matching plasma CA19.9, the panel achieved a higher AUC of 0.97 (95% CI, 0.94-0.99) than CA19.9 (AUC = 0.88; 95% CI, 0.81-0.95, P = 0.005). Adding plasma CA19.9 to the panel increased the AUC from 0.97 (95% CI, 0.94-0.99) to 0.99 (95% CI, 0.97-1.00, P = 0.04), but did not improve the comparison of stage I-IIA PDAC (n = 17) with healthy urine.

CONCLUSIONS

We have established a novel, three-protein biomarker panel that is able to detect patients with early-stage pancreatic cancer in urine specimens.

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.

Interleukin-6/STAT pathway is responsible for the induction of gene expression of REG Iα, a new auto-antigen in Sjögren׳s syndrome patients, in salivary duct epithelial cells

The regenerating gene, Reg, was originally isolated from a rat regenerating islet cDNA library, and its human homolog was named REG Iα. Recently, we reported that REG Iα mRNA as well as its product were overexpressed in ductal epithelial cells in the minor salivary glands of Sjögren׳s syndrome (SS) patients. This study was undertaken to elucidate the role of cytokines and the subsequent intracellular mechanism for induction of REG Iα in the salivary glands of SS patients. We prepared a reporter plasmid containing REG Iα promoter (−1190/+26) upstream of a luciferase reporter gene. The promoter plasmid was introduced by lipofection into human NS-SV-DC and rat A5 salivary ductal cells. The cells were treated with interleukin (IL)-6, IL-8, and a combination of the two. Thereafter transcriptional activity of REG Iα was measured by luciferase assay. We found that IL-6 stimulation, but not IL-8, significantly enhanced the REG Iα promoter activity in salivary ductal cells. Deletion analysis revealed that the region of −141 to −117 of the REG Iα gene was responsible for the promoter activation by IL-6, which contains a consensus sequence for signal transduction and activation of transcription (STAT). The introduction of siRNA for human STAT3 abolished IL-6-induced REG Iα transcription. These results showed that IL-6 stimulation induced REG Iα transcription through STAT3 activation and binding to the consensus sequence of REG Iα promoter in salivary ductal cells. This IL-6/STAT dependent REG Iα induction might play a role in the pathogenesis of SS.

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REG Iα was overexpressed in salivary ductal cells of patients with Sjögren׳s syndrome.

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IL-6 stimulation enhanced the REG Iα gene transcription in salivary ductal cells.

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STAT3 mediated IL-6-induced REG Iα transcription in salivary ductal cells.

Regenerating gene 1B silencing inhibits colon cancer cell HCT116 proliferation and invasion

BACKGROUND

The human regenerating gene 1B (REG1B) is found to be frequently up-regulated in many types of human tumors. It is unclear whether REG1B expression may have therapeutic value in colorectal carcinoma. Additionally, how REG1B is associated with the clinical features of colorectal carcinoma is not known. To investigate the relationship between REG1B and colorectal cancer, we analyzed REG1B expression in clinical specimens and cell lines and the effect of down-regulation of REG1B by short hairpin RNA (shRNA) in HCT116 cells.

METHODS

Paraffin-embedded specimens from 30 pairs of colorectal cancer tissues and adjacent colon tissues were used to investigate the expression of REG1B by immunohistochemistry. We also examined whether REG1B itself may be related to cell proliferation, cell cycle arrest, apoptosis, migration and invasion in colon cancer HCT116 cells.

RESULTS

Our results showed that REG1B was highly expressed in colorectal carcinoma and was significantly associated with cell differentiation status. The results also illustrated that REG1B silencing with shRNA inhibited cell proliferation, migration and invasion but did not induce apoptosis. Furthermore, down-regulation of REG1B induces G1-phase cell cycle arrest in colon cancer cells.

CONCLUSIONS

Knockdown of REG1B can inhibit cell proliferation, migration and invasion. It may act by a mechanism regulating cell cycle progression. Thus, REG1B may be a novel candidate therapeutic target for colorectal cancer.

REG3A accelerates pancreatic cancer cell growth under IL-6-associated inflammatory condition: Involvement of a REG3A-JAK2/STAT3 positive feedback loop

Regenerating gene protein (REG) 3A is a 19 kD secretory pancreas protein with pro-growth function. Previously we demonstrated that overexpression of REG3A, acting as a key molecule for up-regulation of the JAK2/STAT3 pathway, contributed to inflammation-related pancreatic cancer (PaC) development. However the exact network associated with REG3A signaling still remains unclear. Here we determined that exposure of human PaC cells to cytokine IL-6 activated the oncogenic JAK2/STAT3 pathway, which directly upregulated REG3A expression, accelerated cell cycle progression by promoting CyclinD1 expression, and enhancing the expression of the anti-apoptosis Bcl family. Importantly, the activation of REG3A would instead enhance the JAK2/STAT3 pathway to constitute a REG3A-JAK2/STAT3 positive feedback loop, which leads to the amplification of the oncogenic effects of IL-6/JAK2/STAT3, a classic pathway linking to inflammation-related tumorigenesis, ultimately resulting in PaC cell over-proliferation and tumor formation both in vitro and in vivo. Moreover, EGFR was found to mediate the REG3A signal for PaC cell growth and JAK2/STAT3 activation, thus functioning as a REG3A receptor. Collectively, our results provide the first evidence for the presence of the synergistic effect of REG3A and IL-6 on PaC development via a REG3A-JAK2/STAT3 positive feedback loop.

Synergistic activations of REG I α and REG I β promoters by IL-6 and Glucocorticoids through JAK/STAT pathway in human pancreatic β cells

Reg (Regenerating gene) gene was originally isolated from rat regenerating islets and its encoding protein was revealed as an autocrine/paracrine growth factor for β cells. Rat Reg gene is activated in inflammatory conditions for β cell regeneration. In human, although five functional REG family genes (REG Iα, REG Iβ, REG III, HIP/PAP, and REG IV) were isolated, their expressions in β cells under inflammatory conditions remained unclear. In this study, we found that combined addition of IL-6 and dexamethasone (Dx) induced REG Iα and REG Iβ expression in human 1.1B4 β cells. Promoter assay revealed that a signal transducer and activator of transcription- (STAT-) binding site in each promoter of REG Iα (TGCCGGGAA) and REG Iβ (TGCCAGGAA) was essential for the IL-6+Dx-induced promoter activation. A Janus kinase 2 (JAK2) inhibitor significantly inhibited the IL-6+Dx-induced REG Iα and REG Iβ transcription. Electrophoretic mobility shift assay and chromatin immunoprecipitation revealed that IL-6+Dx stimulation increased STAT3 binding to the REG Iα promoter. Furthermore, small interfering RNA-mediated targeting of STAT3 blocked the IL-6+Dx-induced expression of REG Iα and REG Iβ. These results indicate that the expression of REG Iα and REG Iβ should be upregulated in human β cells under inflammatory conditions through the JAK/STAT pathway.

Expression of REG4 in ovarian mucinous tumors

Regenerating islet-deprived gene family, number 4 (REG4), is a novel marker for intestinal differentiation. We performed immunohistochemical studies on REG4, cytokeratin (CK)7, CK20, and caudal type homeobox 2 (CDX2) in 291 ovarian mucinous tumors. There were 226 primary tumors and 65 metastatic tumors. The primary tumors comprised 69/226 mucinous cystadenomas, 79/226 mucinous borderline tumors (64/79 intestinal-type and 15/79 endocervical-like tumors), and 78/226 mucinous carcinomas. We found that REG4 expression was significantly higher in mucinous borderline tumors (30/79, 38.0%) and primary mucinous carcinomas (26/78, 33.3%) than in mucinous cystadenomas (4/69, 5.8%; P<0.05). However, REG4 expression was more commonly associated with intestinal-type, borderline, mucinous tumors rather than the endocervical-like type (30/64 vs. 0/15, P<0.001). There was a significant correlation between the REG4 and CDX2 expression profiles in primary ovarian mucinous tumors (r=0.772, P<0.001). REG4, CDX2, and diffuse CK20 had higher expression frequencies in metastatic lower gastrointestinal adenocarcinoma than in primary mucinous tumors (P<0.01). The CK7/REG4 coordinate expression profile was comparable in diagnostic value to CK7/CK20 or CK7/CDX2 profile. We conclude that REG4 expression is common in mucinous borderline tumors of the intestinal type as it is absent in the endocervical-like form in this series. Expression of CK7/REG4 may contribute to the differential diagnosis between primary and metastatic ovarian mucinous tumors.

Serum regenerating islet-derived 3-alpha is a biomarker of mucosal enteropathies

BACKGROUND

The clinical presentation of organic and functional intestinal disorders can overlap and clinicians often rely on invasive and time-consuming procedures to make a final diagnosis. Regenerating islet-derived 3-alpha (Reg3α) is detectable in the circulation of patients with intestinal graft-versus host disease and patients with inflammatory bowel disease (IBD).

AIM

To determine whether serum Reg3α testing is useful for discriminating mucosal enteropathies from functional intestinal disorders.

METHODS

We prospectively included 47 patients with active coeliac disease (ACD), 13 patients with refractory coeliac disease (RCD), seven patients with common variable immunodeficiency (CVID), 72 patients with active Crohn's disease, 22 patients with active ulcerative colitis (UC) and 28 patients with irritable bowel syndrome (IBS)-related diarrhoea. Sera were also taken from 10 CD patients before and after 6-12 months of a gluten-free diet (GFD) and from 14 patients with IBD before and after induction therapy with Infliximab (IFX). Sera of 119 healthy volunteers were used to determine the cut-off value. Reg3α levels were measured by a commercial ELISA kit.

RESULTS

Levels of Reg3α exceeded the cut-off value of the assay in 43/47(91%) ACD patients, 13/13(100%) RCD patients, 7/7(100%) CVID patients, 65/72(90%) Crohn's disease patients, 17/22(77%) UC patients and one patient with IBS(4%). Reg3α levels distinguished mucosal enteropathies from IBS with a sensitivity of 90% and a specificity of 96%. Reg3α levels significantly decreased in CD patients following a GFD and in IBD patients after treatment with IFX.

CONCLUSION

Reg3α is a serum biomarker of intestinal damage that, combined with clinical data, identifies patients who should undergo invasive tests for diagnosing enteropathies.

Regenerating gene family member 4 promotes growth and migration of gastric cancer through protein kinase B pathway

Regenerating gene family member 4 (REG4), a secreted protein, is overexpressed in several cancers, including gastric cancer. The present study was undertaken to determine the roles of REG4 in the growth of gastric cancer in the nude mice and in the proliferation and migration in human gastric cancer cell line and its downstream signaling pathway. Gastric cancer models were elicited by intraperitoneally injecting MKN45 human gastric cancer cells and the tumor size was measured every other day. The expressions of REG4 mRNA and protein were increased in the gastric cancer tissues from gastric cancer patients. REG4 increased the gastric tumor weight and size in the nude mice, and promoted the proliferation and migration of gastric cancer cells MKN45. Adeno-associated viral (AAV)-mediated knockdown of REG4 decreased the gastric tumor weight and size in the nude mice, and suppressed the proliferation and migration of MKN45 cells. REG4 increased the expression of phosphorylated protein kinase B (Akt). Triciribine hydrate (TCN), the inhibitor of Akt, decreased the gastric tumor weight and size in the nude mice and abolished REG4-induced weight and size increase of the tumor. TCN also inhibited proliferation and migration and abolished REG4-induced proliferation and migration increase of human gastric cell line MKN45. These results indicate that REG4 promotes the growth, proliferation and migration of gastric cancer through Akt pathway.

Manno-oligosaccharide-binding ability of mouse RegIV/GST-fusion protein evaluated by complex formation with the carbohydrate-containing polyamidoamine dendrimer

The carbohydrate-binding properties of the C-type lectin-like mouse RegIV and glutathione S-transferase-fusion protein (GST-mRegIV) were examined using carbohydrate-containing polyamidoamine dendrimers (PD). GST-mRegIV showed affinity for mannan- and manno-oligosaccharide containing PD. Binding was inhibited by manno-oligosaccharides but not by mannose or other tested carbohydrates, suggesting that the binding site may have an extended structure in contrast with typical C-type lectins.

SOCS3 methylation in synergy with Reg3A overexpression promotes cell growth in pancreatic cancer

Pancreatic cancer (PaC) is the fifth leading cause of cancer death in the world, but the molecular mechanisms for its development remain unclear. Regenerating islet-derived protein 3-alpha (Reg3A) has been reported overexpressed in pancreatic inflammation and associated with PaC malignancies, thus believed as a potential target in inflammation-linked pancreatic carcinogenesis. Silencing of suppressor of cytokine signaling SOCS3, a well-known feedback inhibitor of cell proliferation, has been found in many human cancers. Here, we identified that SOCS3 was aberrantly methylated in its CpG island in 3/5 human PaC cell lines and 11/36 cancer tissue samples. SOCS3 restoration by a demethylating agent, 5-aza-2'-deoxycytidine, remarkably suppressed cell proliferation and induced apoptosis of methylated PaC cells. Moreover, we also have shown that Reg3A was highly expressed in PaC cells and tissue samples. Assessment of potential relationship between SOCS3 and Reg3A aberrations in vitro revealed that SOCS3 worked downstream of Reg3A and modulated Reg3A-linked pro-tumor functions. siRNA-mediated SOCS3 knock-down in normal pancreatic epithelial cells and plasmid-transfected SOCS3 overexpression in PaC cells, respectively, resulted in the obvious promotion and inhibition of Reg3A-induced cell proliferation, thereby suggesting SOCS3 negatively regulating Reg3A-mediated PaC progression. In addition, our findings also revealed that JAK/STAT3/NF-κB appear involved in the effect of SOCS3-Reg3A interaction on pancreatic cell growth. In summary, SOCS3 inactivation by methylation was demonstrated to act in synergy with Reg3A overexpression to promote PaC cell growth and maybe the progress of inflammation-linked pancreatic carcinogenesis.

KEY MESSAGES

Reg3A overexpression promoted cell growth in pancreatic cancer. SOCS3 is a key target in cancer by inhibiting cell growth and inducing apoptosis. SOCS3 negatively regulated Reg3A-mediated cell growth in pancreatic cancer. SOCS3 methylation act in synergy with Reg3A overexpression to promote pancreatic cancer cell growth.

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.

Interleukin-22: A Bridge Between Epithelial Innate Host Defense and Immune Cells

Interleukin-22 (IL-22), an IL-10 family cytokine, is produced by various leukocytes. The receptor of IL-22, however, is preferentially detected on peripheral tissue epithelial cells. IL-22 functions as a unique messenger from immune system to tissue epithelial cells and to regulate homeostasis of epithelia. IL-22 is able to directly enhance antimicrobial defense mechanisms in epithelial cells and to facilitate epithelial barrier repair and wound healing process. It, therefore, possesses an irreplaceable role in host defense against certain pathogens that specifically invade epithelial cells. In addition, IL-22 can help to preserve the integrity and homeostasis of various epithelial organs during infection or inflammation. The importance of its tissue-protective function is manifested in many inflammatory situations such as inflammatory bowel diseases (IBD) and hepatitis. On the other hand, as a cytokine, IL-22 is capable of induction of proinflammatory responses, especially in synergy with other cytokines. Consequently, IL-22 contributes to pathogenesis of certain inflammatory diseases for example psoriasis.

Involvement of autoimmunity to REG, a regeneration factor, in patients with primary Sjögren's syndrome

The regenerating gene (Reg) was isolated originally as a gene specifically over-expressed in regenerating pancreatic islets and constitute a growth factor family. Reg gene product (Reg) is important in the pathophysiology of various human inflammatory diseases. Recently, the possible involvement of human REG in the regeneration of salivary ductal epithelial cells of patients with primary Sjögren's syndrome (SS) was reported. However, the expression of the REG family genes in minor salivary glands (MSG) and the occurrence of anti-REG Iα autoantibodies in SS patients were obscured. In this study, we examined the expression of REG family genes in the MSG of SS and screened anti-REG Iα autoantibodies in SS. The mRNA levels of REG family genes in MSG were quantified using real-time reverse transcription-polymerase chain reaction (RT-PCR) and REG Iα expression in the MSG was analysed by immunohistochemistry. The mRNA level of REG Iα in the MSG of SS patients was significantly higher than that of control. REG Iα protein was expressed highly in SS ductal epithelial cells. Anti-REG Iα autoantibodies in the sera were found in 11% of SS. All the MSG in the anti-REG Iα autoantibody-positive group showed REG Iα expression, whereas only 40% showed REG Iα expression in the anti-REG Iα autoantibody-negative group. The anti-REG Iα autoantibody-positive group showed significantly lower saliva secretion and a higher ratio of grade 4 (by Rubin-Holt) in sialography. These data suggest strongly that autoimmunity to REG Iα might play a role in the degeneration of MSG ductal epithelial cells in primary SS.