Reg IV expression is associated with cell growth and prognosis of adenoid cystic carcinoma in the salivary gland

REG4 promotes the proliferation and anti-apoptosis of cancer

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

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

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

The Clinical Significance and Mechanisms of REG4 in Human Cancers

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

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.

Clinicopathologic and molecular characteristics of gastric cancer showing gastric and intestinal mucin phenotype

Gastric cancer (GC), one of the most common human cancers, can be classified into gastric or intestinal phenotype according to mucin expression. TP53 mutation, allelic deletion of the APC gene and nuclear staining of β-catenin are frequently detected in the intestinal phenotype of GC, whereas CDH1 gene mutation, microsatellite instability and DNA hypermethylation of MLH1 are common events in the gastric phenotype of GC. Our Serial Analysis of Gene Expression (SAGE) and Escherichia coli ampicillin secretion trap (CAST) analyses revealed that CDH17, REG4, OLFM4, HOXA10, DSC2, TSPAN8 and TM9SF3 are upregulated in GC and that CLDN18 is downregulated in GC. Expression of CDH17, REG4, HOXA10 and DSC2 and downregulation of CLDN18 are observed in the intestinal phenotype of GC. In contrast, OLFM4 is expressed in the gastric phenotype of GC. Expression of TSPAN8, TM9SF3 and HER2 are not associated with either gastric or intestinal phenotypes. Ectopic CDX2 expression plays a key function in the GC intestinal phenotype. MUC2, CDH17, REG4, DSC2 and ABCB1 are direct targets of CDX2. Importantly, these genes encode transmembrane/secretory proteins, indicating that the microenvironment as well as cancer cells are also different between gastric and intestinal phenotypes of GC.

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.

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

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

Enhanced RegIV expression predicts the intrinsic 5-fluorouracil (5-FU) resistance in advanced gastric cancer

AIM

RegIV, a member of the Regenerating (REG) gene family, may be a marker for the prediction of resistance to 5-fluorouracil (5-FU)-based chemotherapy. However, the relationship between the intrinsic drug resistance of gastric cancer (GC) cells to 5-FU used alone (single FU) or in multidrug therapeutic regimens (5-FU combinations) and RegIV expression has not been investigated.

METHODS

The patient cohort comprised 45 patients with primary GC. The chemoresistance of GC cells to therapeutic regimens consisting of single 5-FU or FU combinations was investigated using the ATP-tumor chemosensitivity assay. The level of RegIV mRNA transcripts was determined by real-time reverse transcriptase-PCR. RegIV expression was evaluated as a novel predictive biomarker for the intrinsic drug resistance of primary GC cells to single 5-FU or 5-FU combinations.

RESULTS

Upregulation of RegIV mRNA transcripts was observed in 36 of the 45 tumor specimens and was positively correlated with the invasive depth of the tumor cells (p = 0.000), the clinical stages (p = 0.000) and the in vitro intrinsic drug resistance of primary GC cells to 5-FU (p = 0.000) or 5-FU combinations.

CONCLUSION

RegIV mRNA transcript level was strongly associated with the intrinsic resistance of GC cells to single 5-FU or 5-FU combinations, suggesting that RegIV may play an important role in the intrinsic resistance of GC cells to 5-FU and that targeted therapy against the RegIV gene could be applied to overcome 5-FU resistance in the treatment of GC.

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

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

REG4 contributes to the invasiveness of pancreatic cancer by upregulating MMP-7 and MMP-9

Recent studies have shown that overexpression of regenerating gene family member 4 (REG4) is associated with the initiation and progression of pancreatic cancer. In our study, we explored the role of REG4 in the invasion of pancreatic cancer. Real-time PCR and Western blot analysis were used to determine REG4 expression in pancreatic cancer cell lines. An MTT assay was carried out to test the effect of REG4 on the growth of pancreatic cancer cells. The involvement of REG4 in cancer cell invasion was examined by Transwell invasion assay. Two MMPs, MMP-7 and MMP-9, were identified from a pool of candidate genes as being related to REG4-induced cell invasion by PCR and Western blotting. Immunohistochemistry was used to confirm the correlation between REG4 and the two MMPs. High expression of REG4 was found in BXPC-3 cells and its culture media. But in PANC-1 and ASPC-1 cell lines, REG4 expression levels were very low, and no detectable protein was found in the culture medium. The MTT and Transwell invasion assays showed that recombinant REG4 protein and BXPC-3 conditioned media significantly promoted the proliferation and invasiveness of pancreatic cancer cells. It was also shown that MMP-7 and MMP-9 are upregulated by REG4 induction using real-time PCR and Western blotting analysis. Immunohistochemical study further verified this result. In conclusion, REG4 promotes not only growth but also in vitro invasiveness of pancreatic cancer cells by upregulating MMP-7 and MMP-9.

Trks are novel oncogenes involved in the induction of neovascularization, tumor progression, and nodal metastasis in oral squamous cell carcinoma

The function of tropomyosin receptor kinase (Trk) family including TrkA, TrkB, and TrkC in cancer remains unknown. The role of Trks in oral squamous cell carcinoma (OSCC) was examined. Knockdown of Trks provided inhibition of growth or invasion and decrease of apoptosis in OSCC cells, which expressed Trks at high levels. VEGF expression was associated with TrkA and TrkB expression; a decrease of VEGF-C and VEGF-D was observed in OSCC cells with TrkB knockdown. TrkC did not affect the expression of VEGF family. An immunohistochemical analysis of 102 OSCCs showed that TrkB expression was related to microvessel density (MVD), lymph vessel density (LVD), and poor prognosis. TrkC expression was correlated with clinical stage, lymph node metastasis, MVD, LVD, and poor prognosis. TrkA expression was associated with VEGF expression, whereas TrkB expression was associated with the expressions of VEGF, VEGF-C and VEGF-D. No significant association was found between the expression of TrkC and genes of the VEGF family. Expression of Trks was not associated with RUNX3 silencing by methylation in OSCC cells. Trks expression was inversely correlated with RUNX3 expression in the OSCC cases. These results suggested that Trks enhances progression of OSCC through angiogenesis and lymphangiogenesis.

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

Aim

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

Methods

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

Results

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

Conclusions

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

Virtual slides

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

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

Expression of MK-1 and RegIV and its clinicopathological significances in the benign and malignant lesions of gallbladder

Background

To study the expression of MK-1 and RegⅣ and to detect their pathological significances in benign and malignant lesions of gallbladder.

Methods

The expression of MK-1 and RegⅣ was detected by immunohistochemical method in paraffin-embedded sections of surgical resected specimens from gallbladder adenocarcinoma (n = 108), peritumoral tissues (n = 46), adenomatous polyp (n = 15), and chronic cholecystitis (n = 35).

Results

The positive rate of MK-1 or RegⅣ expression was significantly higher in gallbladder adenocarcinoma than that in peritumoral tissues (χ²_MK-1 = 18.76, P < 0.01; χ²_RegⅣ = 9.92, P < 0.01), denomatous polyp (χ²_MK-1 = 9.49, P < 0.01; χ²_RegⅣ = 8.59, P < 0.01) and chronic cholecystitis (χ²_MK-1 = 24.11, P < 0.01; χ²_RegⅣ = 19.24, P < 0.01). The positive cases of MK-1 and/or RegⅣ in the benign lesions showed moderately- or severe-atypical hyperplasia of gallbladder epitheli. The positive rates of MK-1 were significantly higher in the cases of well-differentiated adenocarcinoma, no-metastasis of lymph node, and no-invasiveness of regional tissues than those in the ones of differentiated adenocarcinoma, metastasis of lymph node, and invasiveness of regional tissues in gallbladder adenocarcinoma (P < 0.05 or P < 0.01). On the contrary, the positive rates of RegⅣ were significantly lower in the cases of well-differentiated adenocarcinoma, no-metastasis of lymph node, and no-invasiveness of regional tissues than those in the ones of differentiated adenocarcinoma, metastasis of lymph node, and invasiveness of regional tissues in gallbladder adenocarcinoma (P < 0.05 or P < 0.01). Univariate Kaplan-Meier analysis showed that decreased expression of MK-1 (P = 0.09) or increased expression of RegⅣ (P = 0.003) was associated with decreased overall survival. Multivariate Cox regression analysis showed that decreased expression of MK-1 (P = 0.033) and increased expression of RegⅣ (P = 0.008) was an independent prognostic predictor in gallbladder adenocarcinoma.

Conclusions

The expression of MK-1 and/or RegⅣ might be closely related to the carcinogenesis, clinical biological behaviors, and prognosis of gallbladder adenocarcinoma.

Regenerating I messenger RNA and protein expression in the failing human testis: a potential molecular prognostic marker of seminoma

Infertility has been stated as a risk factor for testicular cancer; but currently, there is no prognostic indicator of tumor development from the pathologic testis with impaired spermatogenesis. Regenerating proteins are expressed in many human tissues including the testis, and their role in carcinogenesis has been well documented. In the present work, regenerating I messenger RNA and protein expression and cellular protein localization were studied in testicular biopsies of patients with normal (obstructive azoospermia) or impaired spermatogenesis (nonobstructive azoospermia) and in seminoma testis by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunofluorescence analyses. No significant differences in regenerating I transcripts were reported between the 3 groups studied. However, regenerating I protein was highly expressed in pure seminoma and in placental-like alkaline phosphatase-positive seminiferous tubules with in situ carcinoma. Regenerating I protein levels measured by Western blotting increased from the placental-like alkaline phosphatase-negative distal region of the seminoma to the pure placental-like alkaline phosphatase-positive tumoral region. Importantly, although cells localized in seminiferous tubules of obstructive azoospermic patients with normal spermatogenesis were very slightly labeled, persisting germ, Sertoli, and myoid cells and fibrous tissues were strongly regenerating I positive in seminiferous tubules of nonobstructive azoospermia. These results suggest the possibility to use regenerating I as a prognostic marker of tumoral development in the infertile testis.

Evaluation of REG4 for early diagnosis and prognosis of gastric cancer

We explored the correlation between the development of gastric cancer and the concentration of REG4 and hence the suitability of REG4 as an indicator of the prognosis of patients with GC. Real-time polymerase chain reaction was conducted to detect REG4 messenger RNA expression. The amount of the REG4 protein was measured by immunohistochemistry staining of tissue and enzyme-linked immunosorbent assay of serum. Serum carcinoembryonic antigen and carbohydrate antigen 19-9 concentrations were measured using a commercial automated immunoassay. Real-time polymerase chain reaction results confirmed that REG4 was significantly up-regulated in gastric cancer compared with paired normal mucosa (P < .001). Immunohistochemistry staining revealed that high expression of REG4 correlated with diffuse type, poor differentiation, lymph node metastasis, distant metastasis, and TNM stage III or IV. The mean survival time for patients in the REG4-positive group was significantly less than that in the REG4-negative group (P = .013). The percentage of serum samples that were REG4 positive was 44.0%, which was higher than that for serum carcinoembryonic antigen (P = .039) or carbohydrate antigen 19-9 (P = .012) in TNM stage I and was significantly higher (P = .031) than that in TNM stage II. Thus, REG4 may be not only a prognostic indicator but also a better serum marker than carcinoembryonic antigen and carbohydrate antigen 19-9 for early diagnosis of gastric cancer.

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.

Downregulation of runt-related transcription factor 3 associated with poor prognosis of adenoid cystic and mucoepidermoid carcinomas of the salivary gland

Runt-related transcription factor 3 (RUNX3) is a transcription factor of the transforming growth factor (TGF)-β superfamily and acts as a tumor suppressor gene, which is silenced by hypermethylation of the promoter region in various cancers. In this study, we examined the expression and methylation status of RUNX3 in the salivary gland cancers pleomorphic adenoma (PA), adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). The cytoplasmic expression rates of RUNX3 in PA, ACC and MEC were 65% (13/20), 22.2% (8/36) and 20.6% (7/34), respectively. Low expression or deletion of RUNX3 in ACC and MEC was significantly associated with tumor progression and poor prognosis. Using microdissected cDNA, we found that RUNX3 mRNA expression was lower in ACC and MEC than in PA and noncancerous salivary glands; furthermore, hypermethylation of RUNX3 was detected more frequently in PA (2/8, 25%), ACC (6/8, 75%) and MEC (7/8, 87.5%) than in noncancerous salivary glands (0/8, 0%). Our results suggest that low expression or deletion of RUNX3 in salivary gland tumors might play a pivotal role in tumorigenesis and tumor progression and poor prognosis in the case of salivary gland ACC and MEC. Recovery of the tumor suppressive function of RUNX3 might inhibit tumorigenesis and cancer progression in the human salivary gland.

Serum concentration and expression of Reg IV in patients with esophageal cancer: Age-related elevation of serum Reg IV concentration

Regenerating islet-derived family, member 4 (REG4, which encodes Reg IV) is a marker for cancer and inflammatory bowel disease. This study aimed to investigate the diagnostic utility of Reg IV measurement in sera from esophageal cancer patients. Reg IV expression was examined in 269 esophageal cancer samples by immunostaining and the Reg IV levels in sera were measured from 65 patients with esophageal squamous cell carcinoma (SCC) by enzyme-linked immunosorbent assay. No Reg IV staining was detected in 255 SCC and 4 small cell carcinoma samples, whereas Reg IV was stained in 4 of 10 (40%) adenocarcinoma samples. Serum Reg IV concentration in esophageal SCC patients was significantly higher compared to that of the control subjects (P=0.0003). A significant correlation between serum Reg IV concentration and age was found in control subjects (P<0.0001). When serum Reg IV concentration was analyzed according to age, the distribution of serum Reg IV concentration in patients with esophageal SCC was similar to that of the control subjects. These results suggest that Reg IV expression is highly specific for adenocarcinoma of the esophagus. Further investigation is required to clarify whether Reg IV serves as a serum tumor marker for esophageal cancer.

Immunostaining of gastric cancer with neuroendocrine differentiation: Reg IV-positive neuroendocrine cells are associated with gastrin, serotonin, pancreatic polypeptide and somatostatin

We previously reported that Reg IV is associated with neuroendocrine (NE) differentiation in gastric cancers. The aim was to examine which NE hormone products are related to Reg IV-positive NE cells and their roles in gastric cancers. In the present study, we performed immunohistochemical analysis in a tissue microarray (TMA) of a consecutive series of 630 cases with ten different antibodies, including chromogranin A, synaptophysin and neural cell adhesion molecule (NCAM) as NE differentiation markers, and gastrin, serotonin, calcitonin, gastrin-releasing peptide (GRP), pancreatic polypeptide (PP), somatostatin and glucagon as NE hormones. In 630 cases, we identified 205 (33%) with NE differentiation and 147 (23%) positive for Reg IV. Reg IV-positive cases showed NE differentiation more frequently than Reg IV-negative cases (P < 0.0001). In 205 cases with NE differentiation, Reg IV-positive cases expressed serotonin (P= 0.0032) and somatostatin (P= 0.036) more frequently than Reg IV-negative cases. Double immunofluorescence staining revealed co-expression of Reg IV with gastrin, serotonin and PP. These results indicate that Reg IV might be a mediating factor of several NE hormones.

Activation of PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway is required for the apoptosis-evasion in human salivary adenoid cystic carcinoma: its inhibition by quercetin

Quercetin, one of the most common natural flavonoids, has been reported to possess significant anti-tumor activities both in vitro and in vivo. The present study was to investigate the effects of quercetin on growth and apoptosis in human salivary adenoid cystic carcinoma (ACC). The result from MTT assay showed that quercetin decreased cell viability of both low metastatic cell line ACC-2 and high metastatic cell line ACC-M in a concentration- and time-dependent manner. Moreover, treatment with quercetin resulted in significantly increased apoptosis in ACC cells. Our data also revealed that the apoptosis induced by quercetin treatment was through a mitochondria-dependent pathway which showed close correlation with the down-regulation of the PI3K/Akt/IKK-alpha/NF-kappaB pathway. Most importantly, quercetin significantly prevented in vivo growth of ACC xenografts in nude mice, accompanied by induction of tumor cell apoptosis, suppression of NF-kappaB nuclear translocation, as well as down-regulation of Akt and IKK-alpha activation. In addition, we explored the clinical significance of the PI3K/Akt/IKK-alpha/NF-kappaB signaling axis in ACC by immunohistochemical analysis of tissue specimens followed by the clustering analyses. We determined that the PI3K/Akt/IKK-alpha/NF-kappaB pathway is ubiquitously activated in ACC and plays an essential role in the evasion of apoptosis. Taken together, the results from our study implicated that quercetin would be a promising chemotherapeutic agent against ACC through its function of down-regulating the PI3K/Akt/IKK-alpha/NF-kappaB signaling pathway.

Expression of β-catenin and REG Iα in relation to cell proliferative ability in salivary gland tumors

β-catenin and its target gene products have been thought to play pivotal roles in the progression of various neoplasias. In the present study, we examined the expression of β-catenin and regenerating gene (REG) Iα in salivary gland tumors and investigated its relationship to their cell proliferative ability. Nineteen patients with pleomorphic adenoma (PA) and 17 patients with malignant salivary gland tumors, including 7 adenoid cystic carcinomas, 7 mucoepidermoid carcinomas and 3 polymorphous low-grade adenocarcinomas, were enrolled. The specimens that had been surgically resected from these patients were examined using immunohistochemistry for β-catenin, REG Iα and Ki67. The relationships between clinicopathological features and β-catenin or REG Iα expression were then analyzed. β-catenin immunoreactivity was positive in 14 PAs (73.3%) and 14 malignant salivary gland tumors (82.4%). Four (28.6%) of the 14 β-catenin-positive PAs showed clear β-catenin immunoreactivity at the plasma membrane (membrane type), while 10 (71.4%) showed diffuse immunoreactivity in the cytoplasm and nucleus but not at the plasma membrane (non-membrane type). Twelve (85.9%) of the 14 malignant salivary gland tumors showed non-membrane-type β-catenin expression. Six (31.6%) of the 19 PAs and 10 (58.8%) of the 17 malignant salivary gland tumors were positive for REG Iα expression. PAs with non-membrane-type β-catenin expression showed a significantly higher Ki67 labeling index than PAs with negative or membrane-type expression. Additionally, PAs that were REG Iα-positive showed a significantly higher Ki67 labeling index than those that were negative. Non-membrane-type β-catenin expression was related to REG Iα positivity in PA lesions. β-catenin and its associated REG Iα protein may play a role as growth-promoting factors in the development of salivary gland tumors.

Advances in RegIV and alimentary system neoplasms

RegIV, a novel member of regenerating gene family, is located at 1p12-13.1, encoding a 17-kDa secreted protein, which is constitutively expressed in the epithelium of normal pancreas and gastrointestinal tract, whereas the expression is up-regulated in inflammatory or neoplastic tissues. RegIV is involved in the carcinogenesis, progression, metastasis and drug resistance of alimentary system neoplasms, and is thought to be useful to make a forecast of the prognosis. It may serve as a new important target for the prevention, diagnosis and treatment of gastrointestinal neoplasms.