Death from early colorectal cancer is predicted by the presence of transcripts of the REG gene family

Upregulation of REG IV gene in human intestinal epithelial cells by lipopolysaccharide via downregulation of microRNA-24

The pathophysiology of inflammatory bowel diseases (IBD) reflects a balance between mucosal injury and reparative mechanisms. Some regenerating gene (Reg) family members (REG Iα, REG Iβ and REG IV) are expressed in Crohn's disease (CD) and ulcerative colitis (UC) and involved as proliferative mucosal factors in IBD. We revealed that REG Iα and REG Iβ were induced in cell culture system by IL‐6/IL‐22. Although REG IV was upregulated in IBD biopsy samples, the upregulation of REG IV was not at all induced in cell culture by autoimmune‐related cytokines such as IL‐6, IL‐22 and TNFα. Here, we analysed REG IV expression in LS‐174 T and HT‐29 human intestinal epithelial cells by real‐time RT–PCR and elisa. REG IV expression was induced by lipopolysaccharide (LPS). However, LPS did not activate REG IV promoter activity. As the LPS‐induced upregulation of REG IV was considered to be regulated post‐transcriptionally, we searched targeted microRNA (miR), which revealed that REG IV mRNA has a potential target sequence for miR‐24. We measured the miR‐24 level of LPS‐treated cells and found that the level was significantly lower. The LPS‐induced increase of REG IV mRNA was abolished by the introduction of miR‐24 mimic but not by non‐specific control RNA.

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.

Okamoto model for necrosis and its expansions, CD38-cyclic ADP-ribose signal system for intracellular Ca2+ mobilization and Reg (Regenerating gene protein)-Reg receptor system for cell regeneration

In pancreatic islet cell culture models and animal models, we studied the molecular mechanisms involved in the development of insulin-dependent diabetes. The diabetogenic agents, alloxan and streptozotocin, caused DNA strand breaks, which in turn activated poly(ADP-ribose) polymerase/synthetase (PARP) to deplete NAD+, thereby inhibiting islet β-cell functions such as proinsulin synthesis and ultimately leading to β-cell necrosis. Radical scavengers protected against the formation of DNA strand breaks and inhibition of proinsulin synthesis. Inhibitors of PARP prevented the NAD+ depletion, inhibition of proinsulin synthesis and β-cell death. These findings led to the proposed unifying concept for β-cell damage and its prevention (the Okamoto model). The model met one proof with PARP knockout animals and was further extended by the discovery of cyclic ADP-ribose as the second messenger for Ca2+ mobilization in glucose-induced insulin secretion and by the identification of Reg (Regenerating gene) for β-cell regeneration. Physiological and pathological events found in pancreatic β-cells have been observed in other cells and tissues.

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.

Decreased REG1α expression suppresses growth, invasion and angiogenesis of bladder cancer

BACKGROUND

Previous study has indicated association between REG1α and bladder cancer. The aim of this study was to investigate the role of Regenerating gene I alpha (REG1α) in bladder cancer.

METHODS

The role of REG1α in bladder cancer cell proliferation, migration and VEGF-induced angiogenesis was explored in vitro and in vivo. Immunohistochemistry (IHC) analysis was assessed to determine the expression of REG1α in ten paired bladder cancer and adjacent non-cancerous tissues, and in 296 bladder cancer samples.

RESULTS

Down-regulation of REG1α expression significantly reduced the proliferation, migration, invasion and VEGF-induced angiogenesis in vitro and the growth of xenograft tumors in vivo. VEGF expression in bladder cancer is associated with REG1α expression and recurrence. REG1α was overexpressed in bladder cancer tissues compared with adjacent normal samples. Patients with elevated REG1α exhibited shorter recurrence times and poor survival.

CONCLUSION

Downregulation of REG1α expression can reduce tumor growth, migration, invasion and angiogenesis. Our study demonstrates that REG1α can be used as a marker of recurrence and prognosis in bladder cancer. Therefore, REG1α targeting in bladder cancer patients represents a promising therapeutic strategy.

Up-regulation of REG3A in colorectal cancer cells confers proliferation and correlates with colorectal cancer risk

Colorectal cancer (CRC) is one of the most common malignancies in the world. Previous studies have investigated the altered expression of regenerating islet-derived 3 alpha (REG3A) in various cancers. We aimed at exploring the biological function and the underlying molecular mechanism of REG3A in CRC. In this study, REG3A was found elevated in CRC compared with normal tissues. Further, high REG3A expression level was correlated with bigger tumor size, poorer differentiation, higher tumor stage and lower survival rate. Knockdown of REG3A in two CRC cell lines, LOVO and RKO, significantly inhibited cell proliferation, and increased cells population in G1 phase and cell apoptotic rate. We also found that down-regulation of REG3A in CRC cells notably inhibited cell migration and invasion. Gene set enrichment analysis on The Cancer Genome Atlas dataset showed that Kyoto Encyclopedia of Genes and Genomes (KEGG) DNA replication and base excision repair (BER) pathways were correlative with the REG3A expression, which was further confirmed in CRC cells by Western blot. Moreover, we confirmed the interaction of REG3A and fibronectin in CRC cells. We also found that there was a positive correlation between REG3A expression level and the AKT and ERK1/2 phosphorylation status. These collective data indicated that REG3A overexpression promotes CRC tumorigenesis by activating AKT and ERK1/2 pathways. REG3A may serve as a promising therapeutic strategy for CRC.

Genetic and transcriptional analysis of human host response to healthy gut microbiota

The study of host-microbiota interactions in humans is largely limited to identifying associations between microbial communities and host phenotypes. While these studies have generated important insights on the links between the microbiota and human disease, the assessment of cause-and-effect relationships has been challenging. Although this relationship can be studied in germfree mice, this system is costly, and it is difficult to accurately account for the effects of host genotypic variation and environmental effects seen in humans. Here, we have developed a novel approach to directly investigate the transcriptional changes induced by live microbial communities on human colonic epithelial cells and how these changes are modulated by host genotype. This method is easily scalable to large numbers of host genetic backgrounds and diverse microbiota and can be utilized to elucidate the mechanisms of host-microbiota interactions. Future extensions may also include colonic organoid cultures.

Many studies have demonstrated the importance of the gut microbiota in healthy and disease states. However, establishing the causality of host-microbiota interactions in humans is still challenging. Here, we describe a novel experimental system to define the transcriptional response induced by the microbiota for human cells and to shed light on the molecular mechanisms underlying host-gut microbiota interactions. In primary human colonic epithelial cells, we identified over 6,000 genes whose expression changed at various time points following coculturing with the gut microbiota of a healthy individual. Among the differentially expressed genes we found a 1.8-fold enrichment of genes associated with diseases that have been previously linked to the microbiome, such as obesity and colorectal cancer. In addition, our experimental system allowed us to identify 87 host single nucleotide polymorphisms (SNPs) that show allele-specific expression in 69 genes. Furthermore, for 12 SNPs in 12 different genes, allele-specific expression is conditional on the exposure to the microbiota. Of these 12 genes, 8 have been associated with diseases linked to the gut microbiota, specifically colorectal cancer, obesity, and type 2 diabetes. Our study demonstrates a scalable approach to study host-gut microbiota interactions and can be used to identify putative mechanisms for the interplay between host genetics and the microbiota in health and disease.

IMPORTANCE The study of host-microbiota interactions in humans is largely limited to identifying associations between microbial communities and host phenotypes. While these studies have generated important insights on the links between the microbiota and human disease, the assessment of cause-and-effect relationships has been challenging. Although this relationship can be studied in germfree mice, this system is costly, and it is difficult to accurately account for the effects of host genotypic variation and environmental effects seen in humans. Here, we have developed a novel approach to directly investigate the transcriptional changes induced by live microbial communities on human colonic epithelial cells and how these changes are modulated by host genotype. This method is easily scalable to large numbers of host genetic backgrounds and diverse microbiota and can be utilized to elucidate the mechanisms of host-microbiota interactions. Future extensions may also include colonic organoid cultures.

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.

Hydrogen sulfide-releasing anti-inflammatory drugs for chemoprevention and treatment of cancer

For many years it has been recognized that inhibition of cyclooxygenase enzymes is effective in reducing the incidence of many types of cancer, but the adverse effects of these drug, particularly in the gastrointestinal and cardiovascular systems, limits their utility. Recently developed hydrogen sulfide-releasing anti-inflammatory drugs may be a promising option for cancer chemoprevention. In this paper we review evidence suggesting that these novel compounds are effective in a range of animal models of various types of cancer, while exhibiting greatly reduced toxicity relative to currently marketed non-steroidal anti-inflammatory drugs. Some of the possible mechanisms of action of hydrogen sulfide-releasing anti-inflammatory drugs are also discussed.

Profound Chemopreventative Effects of a Hydrogen Sulfide-Releasing NSAID in the APCMin/+ Mouse Model of Intestinal Tumorigenesis

Nonsteroidal anti-inflammatory drugs have been shown to reduce the incidence of gastrointestinal cancers, but the propensity of these drugs to cause ulcers and bleeding limits their use. H₂S has been shown to be a powerful cytoprotective and anti-inflammatory substance in the digestive system. This study explored the possibility that a H₂S-releasing nonsteroidal anti-inflammatory drug (ATB-346) would be effective in a murine model of hereditary intestinal cancer (APC^Min+ mouse) and investigated potential mechanisms of action via transcriptomics analysis. Daily treatment with ATB-346 was significantly more effective at preventing intestinal polyp formation than naproxen. Significant beneficial effects were seen with a treatment period of only 3–7 days, and reversal of existing polyps was observed in the colon. ATB-346, but not naproxen, significantly decreased expression of intestinal cancer-associated signaling molecules (cMyc, β-catenin). Transcriptomic analysis identified 20 genes that were up-regulated in APC^Min+ mice, 18 of which were reduced to wild-type levels by one week of treatment with ATB-346. ATB-346 is a novel, gastrointestinal-sparing anti-inflammatory drug that potently and rapidly prevents and reverses the development of pre-cancerous lesions in a mouse model of hereditary intestinal tumorigenesis. These effects may be related to the combined effects of suppression of cyclooxygenase and release of H₂S, and correction of most of the APC^Min+-associated alterations in the transcriptome. ATB-346 may represent a promising agent for chemoprevention of tumorigenesis in the GI tract and elsewhere.

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.

Effect of REG Iα protein on angiogenesis in gastric cancer tissues

Regenerating gene (REG) Iα is not only overexpressed in a subset of gastric cancers, but also involved in tumor progression. However, the mechanism by which (REG) Iα promotes tumor growth is not fully understood. In the present study, we investigated whether REG Iα plays a role in angiogenesis during the progression of gastric cancers. Expression of REG Iα and its receptor (EXTL3; exostoses like-3) was examined using immunohistochemistry in specimens of human gastric cancer. Microvessel density (MVD) in gastric cancer tissues was evaluated using an image analysis system after CD34 immunostaining. Relationships among clinicopathological features, REG Iα expression and MVD in gastric cancer tissues were analyzed. Effects of REG Iα protein on HUVEC cells in terms of proliferation and anti-apoptosis were assessed by WST-1 assay and FACS, respectively. Furthermore, the intracellular signaling by which REG Iα exerts its biological roles was examined in vitro. REG Iα expression was significantly related to lymph node metastasis and its receptor EXTL3 was ubiquitously expressed in not only the tumor cells, but also the tumor vessel cells in the gastric cancer tissues. MVD was significantly higher in gastric cancers that were REG Iα-positive than in those that were negative. Treatment with REG Iα protein promoted growth and anti-apoptosis through activation of the ERK and Akt signaling pathways in HUVEC cells, whereas these effects were attenuated by treatment with anti-REG Iα -antibody. REG Iα protein may play a role in angiogenesis during progression of gastric cancer.

Potential prognostic, diagnostic and therapeutic markers for human gastric cancer

The high incidence of gastric cancer (GC) and its consequent mortality rate severely threaten human health. GC is frequently not diagnosed until a relatively advanced stage. Surgery is the only potentially curative treatment. Thus, early screening and diagnosis are critical for improving prognoses in patients with GC. Gastroscopy with biopsy is an appropriate method capable of aiding the diagnosis of specific early GC tumor types; however, the stress caused by this method together with it being excessively expensive makes it difficult to use it as a routine method for screening for GC on a population basis. The currently used tumor marker assays for detecting GC are simple and rapid, but their use is limited by their low sensitivity and specificity. In recent years, several markers have been identified and tested for their clinical relevance in the management of GC. Here, we review the serum-based tumor markers for GC and their clinical significance, focusing on discoveries from microarray/proteomics research. We also review tissue-based GC tumor markers and their clinical application, focusing on discoveries from immunohistochemical research. This review provides a brief description of various tumor markers for the purposes of diagnosis, prognosis and therapeutics, and we include markers already in clinical practice and various forthcoming biomarkers.

REG4 independently predicts better prognosis in non-mucinous colorectal cancer

Introduction

Colorectal cancer (CRC) is one of the world’s three most common cancers and its incidence is rising. To identify patients who benefit from adjuvant therapy requires novel biomarkers. The regenerating islet-derived gene (REG) 4 belongs to a group of small secretory proteins involved in cell proliferation and regeneration. Its up-regulated expression occurs in inflammatory bowel diseases also in gastrointestinal cancers. Reports on the association of REG4 expression with CRC prognosis have been mixed. Our aim was to investigate tumor REG4 expression in CRC patients and its coexpression with other intestinal markers.

Methods

Tumor expression of REG4 was evaluated by immunohistochemistry in 840 consecutive surgically treated CRC patients at Helsinki University Central Hospital. Expression of MUC1, MUC2, MUC5AC, synapthophysin, and chromogranin was evaluated in a subgroup of 220 consecutively operated CRC patients. REG4 expression with clinicopathological parameters, other intestinal markers, and the impact of REG4 expression on survival were assessed.

Results

REG4 expression associated with favorable clinicopathological parameters and with higher overall survival from non-mucinous CRC (p = 0.019). For such patients under 65, its expression was an independent marker of lower risk of death within 5 years that cancer; univariable hazard ratio (HR) = 0.57; 95% confidence interval (CI) (0.34–0.94); multivariable HR = 0.55; 95% CI (0.33–0.92). In non-mucinous CRC, REG4 associated with positive MUC2, MUC4, and MUC5AC expression.

Conclusion

We show, to our knowledge for the first time, that REG4 IHC expression to be an independent marker of favorable prognosis in non-mucinous CRC. Our results contradict those from studies based on quantification of REG4 mRNA levels, a discrepancy warranting further studies.

Microsatellite instability status affects gene expression profiles in early onset colorectal cancer patients

BACKGROUND

The association between microsatellite instability (MSI) status and gene expression profiles in the early onset sporadic colorectal cancer (CRC) has not been clearly established. The aim of this study was to identify the altered gene expression patterns depending on the MSI status of early onset CRC and determine specific biomarkers that could provide novel therapeutic molecular targets in the Turkish population.

MATERIALS AND METHODS

MSI markers (BAT25, BAT26, D2S123, D5S346, and D17S250) were investigated in tumors from 36 early onset sporadic CRC patients in whom gene expression profiles were analyzed previously. The relationship between the gene expression profiles depending on MSI status was evaluated.

RESULTS

A total of 15 tumors (16.66%) were identified as having MSI and 21 tumors (58.33%) were identified as having microsatellite stability (MSS). CK20 and MAP3K8 upregulation, observed in MSS tumors, was significantly associated with lymph node metastasis, recurrence, and/or distant metastasis and a short median survival (P < 0.05). REG1A upregulation is also correlated with recurrence and/or distant metastasis and a short median survival in patients with MSI tumors (P < 0.05).

CONCLUSIONS

High expression levels of CK20 and MAP3K8 in MSS tumors and REG1A in MSI tumors correlated with a poor prognosis in CRC patients. Further studies and validations are required; these genes may provide novel therapeutic molecular targets for the development of anticancer drugs related to MSI status for early onset CRC treatment.

Regulation of colon gene expression by vitamin B6 supplementation

SCOPE

Previous studies have shown that vitamin B6 supplementation suppresses the development of colonic aberrant crypt foci (ACF), precursor lesions of colon cancer, and cell proliferation in mice receiving the colonic carcinogen, azoxymethane (AOM). This study investigated the molecular mechanism of these effects of dietary vitamin B6.

METHODS AND RESULTS

To date, the mechanism by which ACFs develop is not yet fully understood. In a search for factors that play a critical role during ACF development, we examined colon gene expression during early stage of ACF development in AOM-treated mice using DNA microarray analysis. AOM treatment significantly upregulated mRNA closely related to mast cell and cytotoxic T-cell activity. This study also investigated the effect of vitamin B6 supplementation on colon gene expression in AOM-treated mice. We found that vitamin B6 supplementation downregulates Cd8a and Ccl8 mRNA expression, suggesting these candidate genes may play a protective role against colonic ACF development. Furthermore, we examined genomic affects of dietary vitamin B6, and showed that Reg3γ mRNA expression in colons is downregulated by vitamin B6.

CONCLUSION

This study provides an insight into the genomic activities of dietary vitamin B6 that may be protective against colon tumor development.

Significance of regenerating islet-derived type IV gene expression in gastroenterological cancers

The regenerating islet-derived members (Reg), a group of small secretory proteins, which are involved in cell proliferation or differentiation in digestive organs, are upregulated in several gastrointestinal cancers, functioning as trophic or antiapoptotic factors. Regenerating islet-derived type IV (RegIV), a member of the Reg gene family, has been reported to be overexpressed in gastroenterological cancers. RegIV overexpression in tumor cells has been associated with carcinogenesis, cell growth, survival and resistance to apoptosis. Cancer tissue expressing RegIV is generally associated with more malignant characteristics than that without such expression, and RegIV is considered a novel prognostic factor as well as diagnostic marker in some gastroenterological cancers. We previously investigated the expression levels of RegIV mRNA of 202 surgical colorectal cancer specimens with quantitative real-time reverse-transcriptase polymerase chain reaction and reported that a higher level of RegIV gene expression was a significant independent predictor of colorectal cancer. The biologic functions of RegIV protein in cancer tissue, associated with carcinogenesis, anti-apoptosis and invasiveness, are being elucidated by molecular investigations using transfection techniques or neutralizing antibodies of RegIV, and the feasibility of antibody therapy targeting RegIV is being assessed. These studies may lead to novel therapeutic strategies for gastroenterological cancers expressing RegIV. This review article summarizes the current information related to biological functions as well as clinical importance of RegIV gene to clarify the significance of RegIV expression in gastroenterological cancers.

Identification of new altered genes in rat cochleae with noise-induced hearing loss

Because genes that are highly expressed in the cochlea after noise stress may have crucial regulatory roles in hearing, the identification of these genes may be useful for restoring normal auditory function. This study assessed altered gene expression at 1h following the cessation of noise exposure by using microarrays and real-time polymerase chain reaction (qPCR) in rats. In addition, the auditory threshold shifts and morphological changes of hair cells were observed. This study indicated that applied noise induced outer hair cell loss and a 40-50 dB hearing loss. Totally 239 altered genes were involved in the immune system process, response to stress, or response to stimulus. The expression of five up-regulated genes (Reg3b, Lcn2, Serpina3n, Nob1 and Hamp) was confirmed by qPCR. Future experiments will focus on several of these new candidate genes and may provide insight into the underlying auditory pathophysiology.

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.

Expression profile of the REG gene family in colorectal carcinoma

Regenerating (REG) gene family belongs to the calcium-dependent lectin gene superfamily and encodes small multifunctional secretory proteins, which might be involved in cell proliferation, differentiation, and carcinogenesis. To clarify REG expression profile in colorectal carcinoma (CRC), the authors examined the expression of REG Iα, Iβ, III, HIP/PAP, and REG IV by immunohistochemistry on tissue microarray. The expression of REG Iα, III, and HIP/PAP was more frequently observed in the CRCs than adjacent non-neoplastic mucosa (p < 0.001), whereas it was the converse for REG Iβ and IV (p < 0.001). The expression of REG Iα, Iβ, III, and HIP/PAP was negatively correlated with the depth of invasion of CRCs (p < 0.05). The REG Iβ and HIP/PAP were less expressed in CRCs with than without venous invasion (p < 0.05). The positive rates of REG Iα and HIP/PAP were significantly higher in CRCs without than with lymph node metastasis (p < 0.05). Mucinous carcinoma more frequently expressed REG IV protein than well- and moderately differentiated ones (p < 0.05). There was a positive relationship between REG Iα, Iβ, III, and HIP/PAP expression (p < 0.05). Survival analysis indicated the REG Iβ or HIP/PAP expression was positively linked to favorable prognosis of carcinoma patients (p < 0.05). This study indicated that aberrant REG expression might be closely linked to the pathogenesis, invasion, or lymph node metastasis of CRCs. REG Iβ and HIP/PAP could be considered reliable markers of favorable prognosis of CRC patients.

Relationship between RegIV gene expression to outcomes in colorectal cancer

BACKGROUND

Regenerating islet-derived family members (Reg) are superfamily of calcium-dependant lectins that are expressed in the proximal gastrointestinal tract and ectopically at other sites in the setting of tissue injury. The regenerating islet-derived family member 4 (RegIV) gene has been reported in various cancers, associating with diverse functions. This study examined the relation of the relative expression of RegIV gene to clinicopathological factors and outcomes in patients with colorectal cancer (CRC).

METHODS

We studied surgical specimens of cancer tissue and adjacent normal mucosa obtained from 202 patients with untreated CRC. The relative expression levels of RegIV mRNA in cancer and in normal adjacent mucosa were measured by quantitative real-time reverse-transcriptase polymerase chain reaction.

RESULTS

RegIV gene expression was higher in cancer tissue than in adjacent normal mucosa. The multivariate analysis of clinicopathological factors for 5-year overall survival showed a higher level of RegIV gene expression was a significant independent predictor. Overall survival at 5 years differed significantly between patients with high RegIV gene expression and those with low expression.

CONCLUSIONS

Overexpression of the RegIV gene is considered a useful independent predictor of outcomes in patients with CRC.

Expression of Reg family proteins in embryonic stem cells and its modulation by Wnt/beta-catenin signaling

Regenerating islet (Reg) proteins are involved in the proliferation and differentiation of diverse cell types. However, whether embryonic stem cells (ESCs) express Reg genes and their corresponding proteins remains unknown. In this study, we probed the expression of Reg family members by mouse ESCs (mESCs). Mouse Reg1 and Reg3gamma were detected in undifferentiated stem cells. Furthermore, we tested if gastrin--an inducer of Reg1 expression in committed cells--up-regulates the Reg1 gene in mESCs. Gastrin did not affect the expression of Reg1 either in self-renewing mESCs or under conditions permitting their differentiation. Moreover, overexpression of Reg genes found in various forms of cancer has been linked to dysregulated activation of the canonical Wnt/beta-catenin cascade. Given the important roles of Wnt signaling in stem cells, we investigated if activation of Wnt alters the expression of Reg genes in mESCs. Wnt activation led to an increase in Reg1 gene expression with a concomitant increase in the amount of secreted Reg1 protein. Finally, the expression pattern of genes indicative of differentiation was examined in mESCs that were either exposed to soluble Reg1 or overexpressed the Reg1 gene. This is the first account of expression of Reg family members by ESCs. Our results show that the canonical Wnt cascade affects Reg expression and warrants further studies into the potential roles of Reg proteins in stem cell physiology.

Pancreatic stone protein/regenerating protein family in pancreatic and gastrointestinal diseases

Pancreatic stone protein (PSP; reported in 1979), pancreatitis-associated protein (PAP; 1984) and regenerating protein (Reg I; 1988) were discovered independently in the fields of the exocrine (pancreatitis) and endocrine (diabetes) pancreas. Subsequent analysis revealed that PSP and Reg I are identical and PAP belongs to the same protein family. PSP/Reg I and PAP share a selective and specific trypsin cleavage site and result in insoluble fibrils (PTP, PATP). Search for a functional role of PSP had led to the idea that it might serve as an inhibitor in pancreatic stone formation and PSP was renamed lithostathine. Inhibitory effects of lithostathine in stone formation have been questioned. Evidence so far obtained can support a lithogenic role rather than a lithostatic role of PSP. PAP and its isoforms have been investigated mainly regarding responses to inflammation and stress. Reg I and its isoforms have been examined on regeneration, growth and mitogenesis in gastrointestinal neoplastic diseases as well as diabetes. Evidence obtained can be applied in the prediction of prognosis and therapy for inflammatory and neoplastic diseases.

Upregulation of REG Ialpha accelerates tumor progression in pancreatic cancer with diabetes

Diabetes is now generally accepted as a crucial event in the process of pancreatic cancer (PaC). However, molecular mechanisms underlying the relationship between diabetes and PaC are not fully understood. Regenerating gene (REG) Ialpha is a growth factor affecting pancreatic islet beta cells, and it has been shown to be involved in the carcinogenesis in gastrointestinal tract. It is rational to speculate that REG Ialpha plays a potential role in the pathogenesis of PaC with diabetes. The aim of this study was to evaluate the REG Ialpha protein expression profile in PaC with and without diabetes, and define the contribution of REG Ialpha on PaC development. We found that REG Ialpha protein preferentially expressed in cancerous tissues of PaC patients with diabetes by Western blot. REG Ialpha positive cancer cells in PaC with diabetes (n = 38) was significantly higher than that in subjects without diabetes (n = 42, p < 0.05) by immunohistochemical analysis. Furthermore, we found that overexpression of REG Ialpha protein in PaC cell lines resulted in accelerated cell proliferation and consequently tumor growth, both in vitro and in vivo. The findings suggest that REG Ialpha may act as one of the tumor promoter and contribute to the aggressive nature of PaC, especially in the subpopulation with diabetes. This study would shed new insights for understanding the molecular mechanisms underlying the link between diabetes and PaC.

Stat3: linking inflammation to epithelial cancer - more than a "gut" feeling?

Inflammation is an important environmental factor that promotes tumourigenesis and the progression of established cancerous lesions, and recent studies have started to dissect the mechanisms linking the two pathologies. These inflammatory and infectious conditions trigger immune and stromal cell release of soluble mediators which facilitate survival and proliferation of tumour cells in a paracrine manner. In addition, (epi-)genetic mutations affecting oncogenes, tumour-suppressor genes, chromosomal rearrangements and amplifications trigger the release of inflammatory mediators within the tumour microenvironment to promote neoplastic growth in an autocrine manner. These two pathways converge in tumour cells and result in activation of the latent signal transducer and activator of transcription 3 (Stat3) which mediates a transcriptional response favouring survival, proliferation and angiogenesis. The abundance of cytokines that activate Stat3 within the tumour microenvironment, which comprises of members of the interleukin (IL) IL6, IL10 and IL17/23 families, underpins a signaling network that simultaneously promotes the growth of neoplastic epithelium, fuels inflammation and suppresses the host's anti-tumour immune response. Accordingly, aberrant and persistent Stat3 activation is a frequent observation in human cancers of epithelial origin and is often associated with poor outcome.

Here we summarize insights gained from mice harbouring mutations in components of the Stat3 signaling cascade and in particular of gp130, the shared receptor for the IL6 family of cytokines. We focus on the various feed-back and feed-forward loops in which Stat3 provides the signaling node in cells of the tumour and its microenvironment thereby functionally linking excessive inflammation to neoplastic growth. Although these observations are particularly pertinent to gastrointestinal tumours, we suggest that the tumour's addiction to persistent Stat3 activation is likely to also impact on other epithelial cell-derived cancers. These insights provide clues to the judicious interference of the gp130/Stat3 signaling cascade in therapeutically targeting cancer.

gp130-mediated Stat3 activation in enterocytes regulates cell survival and cell-cycle progression during colitis-associated tumorigenesis

Although gastrointestinal cancers are frequently associated with chronic inflammation, the underlying molecular links have not been comprehensively deciphered. Using loss- and gain-of-function mice in a colitis-associated cancer model, we establish here a link comprising the gp130/Stat3 transcription factor signaling axis. Mutagen-induced tumor growth and multiplicity are reduced following intestinal epithelial cell (IEC)-specific Stat3 ablation, while its hyperactivation promotes tumor incidence and growth. Conversely, IEC-specific Stat3 deficiency enhances susceptibility to chemically induced epithelial damage and subsequent mucosal inflammation, while excessive Stat3 activation confers resistance to colitis. Stat3 has the capacity to mediate IL-6- and IL-11-dependent IEC survival and to promote proliferation through G1 and G2/M cell-cycle progression as the common tumor cell-autonomous mechanism that bridges chronic inflammation to tumor promotion.

REG1A predicts recurrence in stage Ta/T1 bladder cancer

AIMS

Stage Ta/T1 urothelial carcinoma of the bladder (Ta/T1 BC) has a marked tendency to recur. Regenerating protein 1 A (REG1A) has been reported to be expressed in human cancers, and it may be positively correlated with patient's prognosis. The aim of the present study was to evaluate the prognostic value of REG1A in Ta/T1 BC.

METHODS

Immunohistochemistry was done on 110 paraffin-embedded specimens of human Ta/T1 BC to detect the proteins REG1A, PCNA and MMP2. The relationships between REG1A expression and the clinical-pathological characteristics of Ta/T1 BC patients were evaluated.

RESULTS

Sixty-five out of 110 specimens were REG1A-positive. Grade and expression levels of MMP2 and REG1A were significantly correlated with the recurrence rate. REG1A expression (Hazard ratio: 3.1; 95% CI: 1.1-8.5; P=0.030) was an independent predictor of recurrence rate in multivariate Cox regression analysis. A significant association between REG1A expression and MMP2 expression (P=0.023) was also observed.

CONCLUSION

Expression of REG1A is an independent predictor of recurrence in Ta/T1 BC.

Thiazolidinediones inhibit REG Ialpha gene transcription in gastrointestinal cancer cells

REG (Regenerating gene) Ialpha protein functions as a growth factor for gastrointestinal cancer cells, and its mRNA expression is strongly associated with a poor prognosis in gastrointestinal cancer patients. We here demonstrated that PPARgamma-agonist thiazolidinediones (TZDs) inhibited cell proliferation and REG Ialpha protein/mRNA expression in gastrointestinal cancer cells. TZDs inhibited the REG Ialpha gene promoter activity, via its cis-acting element which lacked PPAR response element and could not bind to PPARgamma, in PPARgamma-expressing gastrointestinal cancer cells. The inhibition was reversed by co-treatment with a specific PPARgamma-antagonist GW9662. Although TZDs did not inhibit the REG Ialpha gene promoter activity in PPARgamma-non-expressing cells, PPARgamma overexpression in the cells recovered their inhibitory effect. Taken together, TZDs inhibit REG Ialpha gene transcription through a PPARgamma-dependent pathway. The TZD-induced REG Ialpha mRNA reduction was abolished by cycloheximide, indicating the necessity of novel protein(s) synthesis. TZDs may therefore be a candidate for novel anti-cancer drugs for patients with gastrointestinal cancer expressing both REG Ialpha and PPARgamma.

REG1A expression is an independent factor predictive of poor prognosis in patients with breast cancer

BACKGROUND

Regenerating gene I alpha (REG1A) is a growth factor known to affect pancreatic islet beta cells. Although REG1A expression has also been observed in various malignant tumors, the correlation between REG1A expression and the clinicopathological characteristics of breast cancer and patient prognosis has not been evaluated.

METHODS

Resected breast cancer tissues obtained at surgery from 150 breast cancer patients was stained with anti-REG1A antibody, after which the relative area occupied by stained tumor cells was evaluated under a light microscope and correlated with known clinicopathological factors.

RESULTS

Whereas tumor cells were frequently stained with anti-REG1A antibody, cells from normal breast tissue were not stained. REG1A expression in tumors of breast cancer patients with HER2-positive disease was higher than those with HER2-negative disease (P = .0009). The 10-year disease-specific survival rate among patients with lower levels of REG1A was significantly better than among those with higher levels (P = .0002 by log rank test). Multivariate Cox proportional hazard analyses revealed REG1A (hazard ratio, 2.07; 95% confidence interval, 1.93 to 11.29; P = .0005) and axillary lymph node status (hazard ratio, 4.44; 95% confidence interval, 1.52 to 11.29; P = .0003) to be independent factors affecting the 10-year disease-specific survival rate.

CONCLUSION

High levels of REG1A expression within tumors are an independent predictor of poor prognosis in patients with breast cancer.

Identification of tumor-associated antigens by large-scale analysis of genes expressed in human colorectal cancer

Despite the high prevalence of colon cancer in the world and the great interest in targeted anti-cancer therapy, only few tumor-specific gene products have been identified that could serve as targets for the immunological treatment of colorectal cancers. The aim of our study was therefore to identify frequently expressed colon cancer-specific antigens. We performed a large-scale analysis of genes expressed in normal colon and colon cancer tissues isolated from colorectal cancer patients using massively parallel signal sequencing (MPSS). Candidates were additionally subjected to experimental evaluation by semi-quantitative RT-PCR on a cohort of colorectal cancer patients. From a pool of more than 6000 genes identified unambiguously in the analysis, we found 2124 genes that were selectively expressed in colon cancer tissue and 147 genes that were differentially expressed to a significant degree between normal and cancer cells. Differential expression of many genes was confirmed by RT-PCR on a cohort of patients. Despite the fact that deregulated genes were involved in many different cellular pathways, we found that genes expressed in the extracellular space were significantly over-represented in colorectal cancer. Strikingly, we identified a transcript from a chromosome X-linked member of the human endogenous retrovirus (HERV) H family that was frequently and selectively expressed in colon cancer but not in normal tissues. Our data suggest that this sequence should be considered as a target of immunological interventions against colorectal cancer.

REG1A expression is a prognostic marker in colorectal cancer and associated with peritoneal carcinomatosis

By expression profiling of early staged colon carcinomas, we found regenerating islet-derived 1 alpha (REG1A) to be upregulated in patients with an unfavorable clinical outcome. For validation, REG1A expression was quantified in another colorectal cancer (CRC) patient cohort by Taqman PCR. Aside from tumor and normal tissue from 63 nonpretreated CRC patients, 31 mucosa biopsies from healthy individuals as well as 22 adenomas were included in the investigation. REG1A was significantly upregulated in tumor specimens (p < 0.001) and adenoma (p < 0.01) as compared to normal colorectal tissue. REG1A expression in normal peritumoral tissue in turn proved to be significantly elevated compared to mucosa from healthy individuals (p < 0.01). Determination of REG1A expression might be useful for early tumor diagnosis with a sensitivity of 90.6%, and a specificity of 77.9%. REG1A expression was significantly increased in tumors with peritoneal carcinomatosis (p < 0.01). Moreover, REG1A turned out to be a significant predictor of disease-free survival (p < 0.05). In conclusion, we present evidence that REG1A is a molecular marker of prognostic value and is associated with peritoneal carcinomatosis in CRC. REG1A turned out to be already significantly raised in peritumoral normal tissue compared to mucosa from healthy individuals, suggesting a molecular field effect of secreted REG1A.

REG Ialpha is a reliable marker of chemoradiosensitivity in squamous cell esophageal cancer patients

BACKGROUND

A reliable marker of chemoradiosensitivity that would enable appropriate and individualized treatment of thoracic squamous cell esophageal cancer has long been sought. We investigated whether regenerating gene (REG) Ialpha is such a marker.

METHODS

We assessed expression of REG Ialpha in untreated endoscopic biopsy specimens and examined the correlation between REG Ialpha expression and the clinical responses to definitive chemoradiotherapy and prognosis. We also examined the relationship between REG Ialpha expression in the resected tumor and the prognosis of patients who received esophagectomy for thoracic squamous cell esophageal cancer.

RESULTS

Among the 42 patients treated with definitive chemoradiotherapy, 8 of the 23 REG I-positive patients (35%) showed complete responses to chemoradiotherapy, while only one of the 19 REG I-negative patients did so. The survival rate among the REG I-positive patients was significantly better than among the REG I-negative patients. For the 76 patients treated surgically, there was no significant difference in the survival rates among the REG I-positive and REG I-negative patients.

CONCLUSIONS

REG Ialpha expression in squamous cell esophageal carcinoma may be a reliable marker of chemoradiosensitivity. We anticipate that it will enable us to provide more appropriate and individualized treatment to patients of advanced esophageal squamous cell carcinoma.

REG1A expression is an independent factor predictive of poor prognosis in patients with non-small cell lung cancer

Regenerating gene I alpha (REG1A) is a known growth factor affecting pancreatic islet beta cells. Although REG1A expression also has been observed in various tumors, the correlation between REG1A expression and the clinicopathological characteristics of non-small cell lung cancer (NSCLC) and patient prognosis has not been evaluated.

METHODS

We used real-time semi-quantitative reverse transcription polymerase chain reaction to assess REG1A mRNA expression in tumor samples from 86 NSCLC patients. We then correlated REG1A mRNA expression with known clinicopathological factors. We also used immunohistochemical staining to determine the source of REG1A.

RESULTS

Within samples of tumor tissue, the cytosol of tumor cells was stained with anti-REG1A antibody. Cells from normal tissue were not stained. The 5-year over-all survival rate among patients expressing lower levels of REG1A was significantly better than among those expressing higher levels of REG1A (P=0.0031 by log-rank test). Multivariate Cox proportional hazard analyses revealed REG1A (hazard ratio, 2.34; 95% CI, 1.25-5.90; P=0.0055) and pathological stage III (hazard ratio, 3.46; 95% CI, 1.52-14.82; P=0.0012) to be independent factors affecting the 5-year over-all survival rate.

CONCLUSION

High levels of REG1A expression by tumor cells are an independent predictor of a poor prognosis in patients with NSCLC.

Searching urinary tumor markers for bladder cancer using a two-dimensional differential gel electrophoresis (2D-DIGE) approach

Aiming at identifying biomarkers for bladder cancer, the urinary proteome was explored through a two-dimensional gel-based proteomic approach (2D-DIGE) coupled with mass spectrometry and database interrogation. The increased expression of proteins differentially expressed between patients with bladder tumors and controls such as Reg-1 and keratin 10 was confirmed to be associated with bladder cancer progression on bladder cancer cell lines by immunoblotting, and bladder tumors by immunohistochemistry. Moreover, the association of these proteins, especially Reg-1, with tumor staging and clinical outcome was confirmed by immunohistochemistry using an independent series of bladder tumors contained in tissue microarrays (n=292). Furthermore, Reg-1 was quantified using an independent series of urinary specimens (n=80) and provided diagnostic utility to discriminate patients with bladder cancer and controls (area under the curve (AUC=0.88)). Thus, the 2D-DIGE approach has identified Reg-1 as a biomarker for bladder cancer diagnostics, staging, and outcome prognosis.

REG I expression predicts long-term survival among locally advanced thoracic squamous cell esophageal cancer patients treated with neoadjuvant chemoradiotherapy followed by esophagectomy

BACKGROUND

The prognosis for patients with locally advanced thoracic esophageal cancer is extremely unfavorable. We have been administering neoadjuvant chemoradiotherapy (CRT) followed by esophagectomy to these patients and studying whether REG I expression in untreated endoscopic biopsy specimens is predictive of patient responsiveness to CRT and/or survival after treatment.

METHODS

Between 1992 and 2003, 47 patients with T4 (direct invasion of adjacent organs) thoracic esophageal cancers were administered neoadjuvant CRT followed by esophagectomy. REG I expression was assessed in untreated endoscopic biopsy specimens and correlated with clinical and histological responses and survival in 37 patients who had also undergone curative surgery.

RESULTS

Among the 37 cases that received CRT followed by surgery, the therapeutic response rate for neoadjuvant CRT was 68%, and a complete histological response in resected specimens from the primary lesion was achieved in 8 (22%) patients. These clinical and histological responses to neoadjuvant CRT did not significantly correlate with survival, however. By contrast, 9 patients were judged REG-positive based on analysis of their untreated endoscopic biopsy specimens, and their cumulative survival rate was significantly higher than that of the 28 REG-negative patients (P = 0.0073). Univariate analysis showed REG I expression to be a prognostic factor (P = 0.0386) that increased the risk of death 8.4-fold.

CONCLUSIONS

Evaluation of REG I expression in untreated endoscopic biopsy specimens may provide a basis for new treatments of locally advanced thoracic squamous cell esophageal cancers.

Reg I-knockout mice reveal its role in regulation of cell growth that is required in generation and maintenance of the villous structure of small intestine

Reg I (regenerating gene product I) is a growth factor that plays a central role in the generation and regeneration of the gastric mucosal architecture. On the other hand, mouse Reg I mRNA is expressed at the highest levels in the small intestine among the gastrointestinal tissues. In the current study, with the aim to clarify the role of Reg I protein in the small intestine, the temporal and spatial pattern of Reg I expression and the phenotype of Reg I-knockout mice in the tissue were examined. In the wild-type mice, immunohistochemistry localized Reg I protein expression in absorptive cells located in the lower half of the intestinal villi. Reg I expression was undetectable until embryonic day 13 (E13), when the fetal intestine still lacks villous structure; however, it dramatically increased at E17 along with the formation and maturation of the fetal intestinal villi. In the small intestine of the adult Reg I-knockout mice, less densely packed, round-shaped aberrant morphology of the absorptive cells was observed light microscopically, and electron microscopical examination revealed a strikingly loose connection of these cells to the basement membrane. Antiproliferating cell nuclear antigen staining and anti-Ki67 staining demonstrated the marked decrease in the number of proliferating cells in the small intestinal mucosa of the knockout mice. The cell migration speed visualized by one shot labeling of 5-bromodeoxyuridine was significantly slower in the knockout mice. These phenotypes of Reg I-knockout mice emerged, in accordance with the temporal pattern of Reg I expression described above, from E17. Reg I was considered to be a regulator of cell growth that is required to generate and maintain the villous structure of the small intestine.

Potential protein markers for nutritional health effects on colorectal cancer in the mouse as revealed by proteomics analysis

It is suggested that colorectal cancer might be prevented by changes in diet, and vegetable consumption has been demonstrated to have a protective effect. Until now, little is known about the effects of vegetable consumption at the proteome level. Therefore, the effect of increased vegetable intake on the protein expression in the colonic mucosa of healthy mice was studied. Aim was to identify the proteins that are differentially expressed by increased vegetable consumption and to discriminate their possible role in the protection against colorectal cancer. Mice were fed four different vegetable diets, which was followed by analysis of total cellular protein from colonic mucosal cells by a combination of 2-DE and MS. We found 30 proteins that were differentially expressed in one or more diets as compared to the control diet. Six could be identified by MALDI-TOF MS: myosin regulatory light chain 2, carbonic anhydrase I, high-mobility group protein 1, pancreatitis-associated protein 3, glyceraldehyde-3-phosphate dehydrogenase and ATP synthase oligomycin sensitivity conferral protein. Alterations in the levels of these proteins agree with a role in the protection against colon cancer. We conclude that these proteins are suitable markers for the health effect of food on cancer. The observed altered protein levels therefore provide support for the protective effects of vegetables against colorectal cancer.

Reg IV activates the epidermal growth factor receptor/Akt/AP-1 signaling pathway in colon adenocarcinomas

BACKGROUND & AIMS

Reg IV, a secreted protein and member of the Reg multigene family, is up-regulated in malignancies of the human gastrointestinal tract, including colorectal carcinoma (CRC). However, in vitro signal transduction pathway(s) utilized by Reg IV are not yet known.

METHODS

To determine the signaling pathway(s) responsive to Reg IV, we examined the effects of purified recombinant human Reg IV (rhR4) on HCT116 and HT29 colon adenocarcinoma cells.

RESULTS

Addition of rhR4 to cultures led to a dose-dependent increase in cell number similar to that observed after treatment with epidermal growth factor (EGF). In addition, rhR4 treatment resulted in rapid phosphorylation of EGF receptor at Tyr992 and Tyr1068 and Akt at Thr308 and Ser473. Using luciferase reporter gene assays, we demonstrated that Reg IV signaling through EGF receptor and Akt results in increased activator protein-1 (AP-1) transcription factor activity. Real-time reverse-transcription polymerase chain reaction and Western blot analyses revealed quantitative increases in c-Jun, JunB, JunD, and FosB expression associated with increased AP-1 activity. Electrophoretic mobility shift assay further revealed significant increases in AP-1 binding activity in rhR4-treated cells, with increased supershift in the presence of antibodies to JunB, JunD, and FosB. Furthermore, rhR4 treatments led to the increased expression of Bcl-2, Bcl-XL, survivin, and matrilysin, genes associated with a poor prognosis in advanced CRC.

CONCLUSIONS

Reg IV is a potent activator of the EGF receptor/Akt/AP-1 signaling pathway in CRC. Disruption of Reg signaling may have utility as a therapeutic intervention for human gastrointestinal adenocarcinomas.

Overexpression of regenerating islet-derived 1 alpha and 3 alpha genes in human primary liver tumors with β-catenin mutations

The Wnt/beta-catenin signaling pathway is activated in many human hepatocellular carcinomas (HCC). We tried to identify the genes involved in carcinogenesis and progression of HCC with beta-catenin mutations. We used PCR-based subtractive hybridization to compare gene expression between malignant and benign components of a human HCC occurring in pre-existing adenoma activated for beta-catenin. Two of the genes identified belong to the Regenerating gene (REG) family. They encode the Regenerating islet-derived 3 alpha (REG3A/HIP/PAP/REG-III) and 1 alpha (REG1A) proteins, both involved in liver and pancreatic regeneration and proliferation. Using siRNA directed against beta-catenin, we demonstrated that REG3A is a target of beta-catenin signaling in Huh7 hepatoma cells. The upregulation of REG3A and REG1A expression is significantly correlated to the beta-catenin status in 42 HCC and 28 hepatoblastomas characterized for their beta-catenin status. Thus, we report strong evidence that both genes are downstream targets of the Wnt pathway during liver tumorigenesis.

Molecular profiling of ulcerative colitis-associated neoplastic progression

Fundamental differences exist between ulcerative colitis (UC)-associated and sporadic forms of colorectal cancer, including preexisting inflammation, type of dysplasia, and timing of molecular events in carcinogenesis. Transcriptional alterations that occur in UC-associated neoplasia in the progression from normal mucosa through dysplastic epithelium to invasive cancer have not been described. We used Affymetrix U95Av2 microarrays to assess differential gene expression in the neoplastic progression of UC tissue from the colonic mucosa of individuals with benign UC, UC-dysplasia-associated lesions or masses, and UC adenocarcinoma. By correlating transcript alterations across tissue types using a mixed statistical model, we identified 699 genes exhibiting altered expression with dysplasia development. A different expression profile was observed in progression to adenocarcinoma with 392 transcripts exhibiting differential expression. There were 224 transcripts common to both dysplasia and adenocarcinoma. Most of the differentially expressed genes described herein were not previously known to play a role in neoplastic progression in UC, including transcripts affecting cell proliferation and apoptosis, signal transduction and signaling, and DNA repair. The altered expression of five transcripts was confirmed by quantitative real-time reverse-transcription polymerase chain reaction. Based on comparisons with previous studies on sporadic colorectal carcinoma, several similarities were found. There were, however, important differences that suggest that different molecular events may occur in the development of UC-associated neoplasia. Several of these genes demonstrated similar changes in dysplastic and cancerous tissue and may be involved in early cancer formation. Identification of these genes as potential clinical biomarkers may lead to improved early disease diagnosis.

Possible role of REG Ialpha protein in ulcerative colitis and colitic cancer

BACKGROUND AND AIMS

Although regenerating gene (REG) Ialpha protein may be involved in the inflammation and carcinogenesis in the gastrointestinal tract, its pathophysiological role in ulcerative colitis (UC) and the resulting colitic cancer remains unclear. We investigated expression of the REG Ialpha gene and its protein in UC and colitic cancer tissues. We examined whether cytokines are responsible for REG Ialpha gene expression and whether REG Ialpha protein has a trophic and/or an antiapoptotic effect on colon cancer cells.

METHODS

Expression of REG Ialpha mRNA and its gene product in UC tissues was analysed by real time reverse transcription-polymerase chain reaction and immunohistochemistry, respectively. The effects of cytokines on REG Ialpha promoter activity were examined in LoVo cells by luciferase reporter assay. The effects of REG Ialpha protein on growth and H(2)O(2) induced apoptosis were examined in LoVo cells by MTT and TUNEL assays, respectively.

RESULTS

REG Ialpha protein was strongly expressed in inflamed epithelium and in dysplasias and cancerous lesions in UC tissues. The level of REG Ialpha mRNA expression in UC tissues correlated significantly with severity of inflammation and disease duration. REG Ialpha promoter activity was enhanced by stimulation with interferon gamma or interleukin 6. REG Ialpha protein promoted cell growth and conferred resistance to H(2)O(2) induced apoptosis in LoVo cells. REG Ialpha protein promoted Akt phosphorylation and enhanced Bcl-xL and Bcl-2 expression in LoVo cells.

CONCLUSIONS

The REG Ialpha gene is inducible by cytokines and its gene product may function as a mitogenic and/or an antiapoptotic factor in the UC-colitic cancer sequence.

Opposite roles of human pancreatitis-associated protein and REG1A expression in hepatocellular carcinoma: association of pancreatitis-associated protein expression with low-stage hepatocellular carcinoma, beta-catenin mutation, and favorable prognosis

PURPOSE

Pancreatitis-associated protein (PAP) and regenerating protein 1 alpha (Reg1A) are up-regulated during the pancreas regeneration. This study is to investigate the clinicopathologic denotation of their expression in hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

PAP and REG1A mRNA levels were measured in 265 surgically removed unifocal primary HCCs using reverse transcription-PCR.

RESULTS

PAP and REG1A mRNAs were detected in 97 (36.6%) and 55 (20.8%) HCCs, respectively, including 46 with coexpression but in none of the 219 nontumorous livers. HCCs with PAP expression correlated with low-stage tumors without evidence of vascular invasion (P = 0.013) but the REG1A expression did not. By a combination analysis, HCCs with PAP expression alone showed the lowest frequency of p53 mutation (P < 0.036), the highest rates of grade 1 and low-stage tumors (P < 0.007 and P < 0.001, respectively), less frequent early tumor recurrence (P = 0.051), and hence a better 5-year survival (P = 0.044) than groups expressing PAP and REG1A, REG1A alone, and neither PAP or REG1A. Besides, PAP expressing HCCs had significantly frequent beta-catenin mutation, regardless of REG1A expression, P < 0.00001. In the subset of HCCs that has no mutations of p53 and beta-catenin but showed PAP expression, coexpression of REG1A and PAP was associated with more frequent vascular invasion than PAP expression alone (P < 0.005).

CONCLUSIONS

These data suggest that PAP expression designate a subset of low-grade, low-stage HCC with frequent beta-catenin mutation and hence more favorable prognosis, whereas further genetic or epigenetic alterations, such as p53 mutation and REG1A expression, lead to more advanced HCCs.

Gastric achlorhydria in H/K-ATPase-deficient (Atp4a(-/-)) mice causes severe hyperplasia, mucocystic metaplasia and upregulation of growth factors

BACKGROUND

Gastric neoplasia is common in humans, yet controversy remains over contributions of chronic achlorhydria, gastrinemia and hyperplasia, to cancer risk. To study this, mice lacking the gastric H/K-ATPase (Atp4a(-/-) mice) were used to determine whether chronic loss of acid secretion, with attendant hypergastrinemia, predisposes to cancer phenotype.

METHODS

Atp4a(-/-) and Atp4a(+/+) mice, paired for age and gender, were examined at 3, 8, 12 and 20 months for histopathology, and for expression of the trefoil factor family (TFF)1-3, Reg IIIbeta, gamma and delta, osteopontin, CD44, chromogranin A, Crp-ductin, and galectin, all of which are important in cell growth.

RESULTS

By 8 months, the glandular stomach of the Atp4a(-/-) mice doubled in weight and thickness, and several modulators of growth were increased. Female Atp4a(-/-) mice were more hyperplastic than Atp4a(-/-) males at 12 and 20 months. By 1 year, severe mucocystic hyperplasia, incomplete intestinal metaplasia, ciliated metaplasia, a shift in mucins from neutral to acidic, and inflammation were widespread. Cells in the mucus pit zone developed a pyloric-type appearance, containing large hyaline-like, periodic acid-Schiff (PAS)-negative/alcian blue-negative inclusions. But critical characteristics of gastric neoplasia, such as nuclear atypia, invasion into the muscularis mucosa, and metastases were absent. In Atp4a(-/-) mice, chromogranin A and histidine decarboxylase, RegIIIgamma and delta, TFF3, osteopontin and CD44 were upregulated while Reg IIIbeta, and TFF1 were reduced.

CONCLUSIONS

Chronic achlorhydria and hypergastrinemia in aged Atp4a(-/-) mice produced progressive hyperplasia, mucocystic and incomplete intestinal metaplasia, and the upregulation of growth factors without histological evidence of neoplasia.

Reg IV: a promising marker of hormone refractory metastatic prostate cancer

The diagnosis and management of prostate cancer is hampered by the absence of markers capable of identifying patients with metastatic disease. In order to identify potential new markers for prostate cancer, we compared gene expression signatures of matched androgen-dependent and hormone refractory prostate cancer xenografts. One candidate gene overexpressed in a hormone refractory xenograft was homologous to the regenerating protein gene family, a group of secreted proteins expressed in the gastrointestinal tract and overexpressed in inflammatory bowel disease and cancer. This gene, Reg IV, was confirmed to be differentially expressed in the LAPC-9 hormone refractory xenograft. Consistent with its up-regulation in a hormone refractory xenograft, it is expressed in several prostate tumors after neoadjuvant hormone ablation therapy. As predicted by its sequence homology, it is secreted from transiently transfected cells. It is also expressed strongly in a majority of hormone refractory metastases represented on two high-density tissue microarrays. In comparison, it is not expressed by any normal prostate specimens and only at low levels in approximately 40% of primary tumors. These data support Reg IV as a candidate marker for hormone refractory metastatic prostate cancer.

Proteomic analysis of urine in patients with intestinal segments transposed into the urinary tract

Intestinal segments are used to replace or reconstruct the urinary bladder when it has become dysfunctional or develops life-threatening disease such as cancer. The quality of life in patients with intestinal segments used to either enlarge or completely replace the native bladder is adversely affected by recurrent urinary tract infections, excessive mucus production and the occasional development of malignancy. At present, there is no reliable method of predicting or noninvasively monitoring these patients for the development of these complications. The characterisation of proteins secreted into urine from the transposed intestinal segments could serve as important indicators of these clinical complications. Urine is an ideal source of material in which to search for biomarkers, since it bathes the affected tissues and can be obtained relatively easily by noninvasive methods. The urinary proteome of patients with intestinal segments transposed into the urinary tract is unknown and we present the first global description of the urinary protein profile in these patients. Sample preparation is a critical step in achieving accurate and reliable data. We describe a method to prepare urinary proteins that was compatible with their subsequent analysis using two-dimensional polyacrylamide gel electrophoresis. This method helped to overcome some of the technical problems encountered in analysing urine from this patient cohort. The method was used to analyse urinary proteins recovered from five healthy controls and ten patients with intestinal segments transposed into the urinary tract. Four low molecular weight proteins were found to be present in nine out of ten for the patient group but for none of the healthy controls. The four proteins were identified as lithostathine-1 alpha precursor, pancreatitis associated protein-1 precursor, liver fatty acid binding protein and testis expressed protein-12. The role of these proteins as potential biomarkers of intestinal cell activity within the reconstructed bladder is discussed.

The multifunctional family of secreted proteins containing a C-type lectin-like domain linked to a short N-terminal peptide

PSP/Lithostathine/PTP/regI, PAP/p23/HIP, reg1L, regIV and "similar to PAP" are the members of a multifunctional family of secreted proteins containing a C-type lectin-like domain linked to a short N-terminal peptide. The expression of this group of proteins is controlled by complex mechanisms, some members being constitutively expressed in certain tissues while, in others, they require activation by several factors. These members have several apparently unrelated biological effects, depending on the member studied and the target cell. These proteins may act as mitogenic, antiapoptotic or anti-inflammatory factors, can regulate cellular adhesion, promote bacterial aggregation, inhibit CaCO3 crystal growth or increase resistance to antitumoral agents. The presence of specific receptors for these proteins is suggested because biological effects were observed after the addition of purified protein to culture media or after systemic administration to animals, whereas other biological effects could be explained by their biochemical capacity to form homo or heteromers or to form insoluble fibrils at physiological pH.