Expression of the EGF family in gastric cancer: downregulation of HER4 and its activating ligand NRG4

The journey towards physiology and pathology: Tracing the path of neuregulin 4

Neuregulin 4 (Nrg4), an epidermal growth factor (EGF) family member, can bind to and activate the ErbB4 receptor tyrosine kinase. Nrg4 has five different isoforms by alternative splicing and performs a wide variety of functions. Nrg4 is involved in a spectrum of physiological processes including neurobiogenesis, lipid metabolism, glucose metabolism, thermogenesis, and angiogenesis. In pathological processes, Nrg4 inhibits inflammatory factor levels and suppresses apoptosis in inflammatory diseases. In addition, Nrg4 could ameliorate obesity, insulin resistance, and cardiovascular diseases. Furthermore, Nrg4 improves non-alcoholic fatty liver disease (NAFLD) by promoting autophagy, improving lipid metabolism, and inhibiting cell death of hepatocytes. Besides, Nrg4 is closely related to the development of cancer, hyperthyroidism, and some other diseases. Therefore, elucidation of the functional role and mechanisms of Nrg4 will provide a clearer view of the therapeutic potential and possible risks of Nrg4.

The Role of Adipokines and Myokines in the Pathogenesis of Different Obesity Phenotypes-New Perspectives

Obesity is a characteristic disease of the twenty-first century that is affecting an increasing percentage of society. Obesity expresses itself in different phenotypes: normal-weight obesity (NWO), metabolically obese normal-weight (MONW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUO). A range of pathophysiological mechanisms underlie the occurrence of obesity, including inflammation, oxidative stress, adipokine secretion, and other processes related to the pathophysiology of adipose tissue (AT). Body mass index (BMI) is the key indicator in the diagnosis of obesity; however, in the case of the NWO and MONW phenotypes, the metabolic disturbances are present despite BMI being within the normal range. On the other hand, MHO subjects with elevated BMI values do not present metabolic abnormalities. The MUO phenotype involves both a high BMI value and an abnormal metabolic profile. In this regard, attention has been focused on the variety of molecules produced by AT and their role in the development of obesity. Nesfatin-1, neuregulin 4, myonectin, irisin, and brain-derived neurotrophic factor (BDNF) all seem to have protective effects against obesity. The primary mechanism underlying the action of nesfatin-1 involves an increase in insulin sensitivity and reduced food intake. Neuregulin 4 sup-presses lipogenesis, decreases lipid accumulation, and reduces chronic low-grade inflammation. Myonectin lowers the amount of fatty acids in the bloodstream by increasing their absorption in the liver and AT. Irisin stimulates the browning of white adipose tissue (WAT) and consequently in-creases energy expenditure, additionally regulating glucose metabolism. Another molecule, BDNF, has anorexigenic effects. Decorin protects against the development of hyperglycemia, but may also contribute to proinflammatory processes. Similar effects are shown in the case of visfatin and chemerin, which may predispose to obesity. Visfatin increases adipogenesis, causes cholesterol accumulation in macrophages, and contributes to the development of glucose intolerance. Chemerin induces angiogenesis, which promotes the expansion of AT. This review aims to discuss the role of adipokines and myokines in the pathogenesis of the different obesity phenotypes.

Glucose upregulates amphiregulin in oral dysplastic keratinocytes: A potential role in diabetes-associated oral carcinogenesis

BACKGROUND

Compelling evidence implicates diabetes-associated hyperglycemia as a promoter of tumor progression in oral potentially malignant disorders (OPMD). Yet, information on hyperglycemia-induced cell signaling networks in oral oncology remains limited. Our group recently reported that glucose-rich conditions significantly enhance oral dysplastic keratinocyte viability and migration through epidermal growth factor receptor (EGFR) activation, a pathway strongly linked to oral carcinogenesis. Here, we investigated the basal metabolic phenotype in these cells and whether specific glucose-responsive EGFR ligands mediate these responses.

METHODS

Cell energy phenotype and lactate concentration were evaluated via commercially available assays. EGFR ligands in response to normal (5 mM) or high (20 mM) glucose were analyzed by quantitative real-time PCR, ELISA, and western blotting. Cell viability and migration assays were performed in the presence of pharmacological inhibitors or RNA interference.

RESULTS

When compared to normal keratinocytes, basal glycolysis in oral dysplastic keratinocytes was significantly elevated. In highly glycolytic cells, high glucose-activated EGFR increasing viability and migration. Notably, we identified amphiregulin (AREG) as the predominant glucose-induced EGFR ligand. Indeed, enhanced cell migration in response to high glucose was blunted by EGFR inhibitor cetuximab and AREG siRNA. Conversely, AREG treatment under normal glucose conditions significantly increased cell viability, migration, lactate levels, and expression of glycolytic marker pyruvate kinase M2.

CONCLUSION

These novel findings point to AREG as a potential high glucose-induced EGFR activating ligand in highly glycolytic oral dysplastic keratinocytes. Future studies are warranted to gain more insight into the role of AREG in hyperglycemia-associated OPMD tumor progression.

Prognostic biomarkers and molecular pathways mediating Helicobacter pylori–induced gastric cancer: a network-biology approach

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori–induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori–induced cancer compared with the H. pylori–positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori–induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori–induced GC. However, experimental validation is necessary in the future.

Flotillin-2 regulates epidermal growth factor receptor activation, degradation by Cbl-mediated ubiquitination, and cancer growth

Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in various cancers. The ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene (Cbl) regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. Here, we used stable isotope labeling with amino acids in cell culture mass spectrometry to compare Cbl complexes with or without epidermal growth factor (EGF) stimulation. We identified over a hundred novel Cbl interactors, and a secondary siRNA screen found that knockdown of Flotillin-2 (FLOT2) led to increased phosphorylation and degradation of EGFR upon EGF stimulation in HeLa cells. In PC9 and H441 cells, FLOT2 knockdown increased EGF-stimulated EGFR phosphorylation, ubiquitination, and downstream signaling, reversible by EGFR inhibitor erlotinib. CRISPR knockout (KO) of FLOT2 in HeLa cells confirmed EGFR downregulation, increased signaling, and increased dimerization and endosomal trafficking. Furthermore, we determined that FLOT2 interacted with both Cbl and EGFR. EGFR downregulation upon FLOT2 loss was Cbl dependent, as coknockdown of Cbl and Cbl-b restored EGFR levels. In addition, FLOT2 overexpression decreased EGFR signaling and growth. Overexpression of wildtype (WT) FLOT2, but not the soluble G2A FLOT2 mutant, inhibited EGFR phosphorylation upon EGF stimulation in HEK293T cells. FLOT2 loss induced EGFR-dependent proliferation and anchorage-independent growth. Lastly, FLOT2 KO increased tumor formation and tumor volume in nude mice and NSG mice, respectively. Together, these data demonstrated that FLOT2 negatively regulated EGFR activation and dimerization, as well as its subsequent ubiquitination, endosomal trafficking, and degradation, leading to reduced proliferation in vitro and in vivo.

Effects of H2O2 Treatment Combined With PI3K Inhibitor and MEK Inhibitor in AGS Cells: Oxidative Stress Outcomes in a Model of Gastric Cancer

Gastric cancer is worldwide the fifth and third cancer for incidence and mortality, respectively. Stomach wall is daily exposed to oxidative stress and BER system has a key role in the defense from oxidation-induced DNA damage, whilst ErbB receptors have important roles in the pathogenesis of cancer. We used AGS cells as an aggressive gastric carcinoma cell model, treated with H₂O₂ alone or combined with ErbB signaling pathway inhibitors, to evaluate the effects of oxidative stress in gastric cancer, focusing on the modulation of ErbB signaling pathways and their eventual cross-talk with BER system. We showed that treatment with H₂O₂ combined with PI3K/AKT and MEK inhibitors influenced cell morphology and resulted in a reduction of cancer cell viability. Migration ability was reduced after H₂O₂ treatment alone or combined with MEK inhibitor and after PI3K/AKT inhibitor alone. Western blotting analysis showed that oxidative stress stimulated EGFR pathway favoring the MAPKs activation at the expense of PI3K/AKT pathway. Gene expression analysis by RT-qPCR showed ErbB2 and OGG1 increase under oxidative stress conditions. Therefore, we suggest that in AGS cells a pro-oxidant treatment can reduce gastric cancer cell growth and migration via a different modulation of PI3K and MAPKs pathways. Moreover, the observed ErbB2 and OGG1 induction is a cellular response to protect the cells from H₂O₂-induced cell death. In conclusion, to tailor specific combinations of therapies and to decide which strategy to use, administration of a chemotherapy that increases intracellular ROS to toxic levels, might not only be dependent on the tumor type, but also on the molecular targeting therapy used.

Focal amplifications are associated with chromothripsis events and diverse prognoses in gastric cardia adenocarcinoma

The role of focal amplifications and extrachromosomal DNA (ecDNA) is unknown in gastric cardia adenocarcinoma (GCA). Here, we identify frequent focal amplifications and ecDNAs in Chinese GCA patient samples, and find focal amplifications in the GCA cohort are associated with the chromothripsis process and may be induced by accumulated DNA damage due to local dietary habits. We observe diverse correlations between the presence of oncogene focal amplifications and prognosis, where ERBB2 focal amplifications positively correlate with prognosis and EGFR focal amplifications negatively correlate with prognosis. Large-scale ERBB2 immunohistochemistry results from 1668 GCA patients show survival probability of ERBB2 positive patients is lower than that of ERBB2 negative patients when their surviving time is under 2 years, however, the tendency is opposite when their surviving time is longer than 2 years. Our observations indicate that the ERBB2 focal amplifications may represent a good prognostic marker in GCA patients.

Alternative Splicing Events in Tumor Immune Infiltration in Colorectal Cancer

Despite extensive research, the exact mechanisms involved in colorectal cancer (CRC) etiology and pathogenesis remain unclear. This study aimed to examine the correlation between tumor-associated alternative splicing (AS) events and tumor immune infiltration (TII) in CRC. We analyzed transcriptome profiling and clinical CRC data from The Cancer Genome Atlas (TCGA) database and lists of AS-related and immune-related signatures from the SpliceSeq and Innate databases, respectively to develop and validate a risk model of differential AS events and subsequently a TII risk model. We then conducted a two-factor survival analysis to study the association between TII and AS risk and evaluated the associations between immune signatures and six types of immune cells based on the TIMER database. Subsequently, we studied the distribution of six types of TII cells in high- and low-risk groups for seven AS events and in total. We obtained the profiles of AS events/genes for 484 patients, which included 473 CRC tumor samples and 41 corresponding normal samples, and detected 22581 AS events in 8122 genes. Exon Skip (ES) (8446) and Mutually Exclusive Exons (ME) (74) exhibited the most and fewest AS events, respectively. We then classified the 433 patients with CRC into low-risk (n = 217) and high-risk (n = 216) groups based on the median risk score in different AS events. Compared with patients with low-risk scores (mortality = 11.8%), patients with high-risk scores were associated with poor overall survival (mortality = 27.6%). The risk score, cancer stage, and pathological stage (T, M, and N) were closely correlated with prognosis in patients with CRC (P < 0.001). We identified 6479 differentially expressed genes from the transcriptome profiles of CRC and intersected 468 differential immune-related signatures. High-AS-risk and high-TII-risk predicted a poor prognosis in CRC. Different AS types were associated with different TII risk characteristics. Alternate Acceptor site (AA) and Alternate Promoter (AP) events directly affected the concentration of CD4T cells, and the level of CD8T cells was closely correlated with Alternate Terminator (AT) and Exon Skip (ES) events. Thus, the concentration of CD4T and CD8T cells in the CRC immune microenvironment was not specifically modulated by AS. However, B cell, dendritic cell, macrophage, and neutrophilic cell levels were strongly correlated with AS events. These results indicate adverse associations between AS event risk levels and immune cell infiltration density. Taken together, our findings show a clear association between tumor-associated alternative splicing and immune cell infiltration events and patient outcome and could form a basis for the identification of novel markers and therapeutic targets for CRC and other cancers in the future.

A signature of seven immune-related genes predicts overall survival in male gastric cancer patients

Background

Gastric cancer (GC) has a high mortality rate and is one of the most fatal malignant tumours. Male sex has been proven as an independent risk factor for GC. This study aimed to identify immune-related genes (IRGs) associated with the prognosis of male GC.

Methods

RNA sequencing and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed IRGs between male GC and normal tissues were identified by integrated bioinformatics analysis. Univariate and multivariate Cox regression analyses were applied to screen survival-associated IRGs. Then, GC patients were separated into high- and low-risk groups based on the median risk score. Furthermore, a nomogram was constructed based on the TCGA dataset. The prognostic value of the risk signature model was evaluated by Kaplan-Meier curve, receiver operating characteristic (ROC), Harrell’s concordance index and calibration curves. In addition, the gene expression dataset from the Gene Expression Omnibus (GEO) was also downloaded for external validation. The relative proportions of 22 types of infiltrating immune cells in each male GC sample were evaluated using CIBERSORT.

Results

A total of 276 differentially expressed IRGs were screened, including 189 up-regulated and 87 down-regulated genes. Subsequently, a seven-IRGs signature (LCN12, CCL21, RNASE2, CGB5, NRG4, AGTR1 and NPR3) was identified to be significantly associated with the overall survival (OS) of male GC patients. Survival analysis indicated that patients in the high-risk group exhibited a poor clinical outcome. The results of multivariate analysis revealed that the risk score was an independent prognostic factor. The established nomogram could be used to evaluate the prognosis of individual male GC patients. Further analysis showed that the prognostic model had excellent predictive performance in both TCGA and validated cohorts. Besides, the results of tumour-infiltrating immune cell analysis indicated that the seven-IRGs signature could reflect the status of the tumour immune microenvironment.

Conclusions

Our study developed a novel seven-IRGs risk signature for individualized survival prediction of male GC patients.

Eradication of Helicobacter pylori and Gastric Cancer: A Controversial Relationship

Worldwide, gastric cancer (GC) represents the fifth cancer for incidence, and the third as cause of death in developed countries. Indeed, it resulted in more than 780,000 deaths in 2018. Helicobacter pylori appears to be responsible for the majority of these cancers. On the basis of recent studies, and either alone or combined with additional etiological factors, H. pylori is considered a “type I carcinogen.” Over recent decades, new insights have been obtained into the strategies that have been adopted by H. pylori to survive the acidic conditions of the gastric environment, and to result in persistent infection, and dysregulation of host functions. The multistep processes involved in the development of GC are initiated by transition of the mucosa into chronic non-atrophic gastritis, which is primarily triggered by infection with H. pylori. This gastritis then progresses into atrophic gastritis and intestinal metaplasia, and then to dysplasia, and following Correa’s cascade, to adenocarcinoma. The use of antibiotics for eradication of H. pylori can reduce the incidence of precancerous lesions only in the early stages of gastric carcinogenesis. Here, we first survey the etiology and risk factors of GC, and then we analyze the mechanisms underlying tumorigenesis induced by H. pylori, focusing attention on virulence factor CagA, inflammation, oxidative stress, and ErbB2 receptor tyrosine kinase. Moreover, we investigate the relationships between H. pylori eradication therapy and other diseases, considering not only cardia (upper stomach) cancers and Barrett’s esophagus, but also asthma and allergies, through discussion of the “hygiene hypothesis. ” This hypothesis suggests that improved hygiene and antibiotic use in early life reduces microbial exposure, such that the immune response does not become primed, and individuals are not protected against atopic disorders, asthma, and autoimmune diseases. Finally, we overview recent advances to uncover the complex interplay between H. pylori and the gut microbiota during gastric carcinogenesis, as characterized by reduced bacterial diversity and increased microbial dysbiosis. Indeed, it is of particular importance to identify the bacterial taxa of the stomach that might predict the outcome of gastric disease through the stages of Correa’s cascade, to improve prevention and therapy of gastric carcinoma.

Neuregulins in Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), are typically characterized by progressive neuronal loss and neurological dysfunctions in the nervous system, affecting both memory and motor functions. Neuregulins (NRGs) belong to the epidermal growth factor (EGF)-like family of extracellular ligands and they play an important role in the development, maintenance, and repair of both the central nervous system (CNS) and peripheral nervous system (PNS) through the ErbB signaling pathway. They also regulate multiple intercellular signal transduction and participate in a wide range of biological processes, such as differentiation, migration, and myelination. In this review article, we summarized research on the changes and roles of NRGs in neurodegenerative diseases, especially in AD. We elaborated on the structural features of each NRG subtype and roles of NRG/ErbB signaling networks in neurodegenerative diseases. We also discussed the therapeutic potential of NRGs in the symptom remission of neurodegenerative diseases, which may offer hope for advancing related treatment.

A systematic review of the association of neuregulin 4, a brown fat-enriched secreted factor, with obesity and related metabolic disturbances

Neuregulin 4 (Nrg4), a novel brown fat-enriched hormone, plays a key role in the modulation of glucose and lipid metabolism and energy balance. Recent data have demonstrated that the expression of Nrg4 is substantially down-regulated in mouse and human obesity, making its regulatory aspect intriguing. Because of the close relationship between Nrg4, obesity, and associated metabolic diseases, this systematic review aimed to assess the association of Nrg4 with obesity and related metabolic disturbances, emphasizing its possible mechanisms of action in these disorders. We searched PubMed/Medline, ScienceDirect, Scopus, EMBASE, ProQuest, and Google Scholar up until June 2019. The evidence reviewed here indicates that Nrg4 may contribute to the prevention of obesity and related metabolic complications by elevating brown adipose tissue activity, increasing the expression of thermogenic markers, decreasing the expression of lipogenic/adipogenic genes, exacerbating white adipose tissue browning, increasing the number of brite/beige adipocytes, promoting hepatic fat oxidation and ketogenesis, inducing neurite outgrowth, enhancing blood vessels in adipose tissue, increasing the circulatory levels of healthy adipokines, and improving glucose homeostasis. Thus, Nrg4 appears to be a novel therapeutic strategy for the treatment of obesity and associated metabolic complications. However, prospective cohort studies are warranted to confirm these outcomes.

Machine-learning based radiogenomics analysis of MRI features and metagenes in glioblastoma multiforme patients with different survival time

Background

This study aimed to examine multi‐dimensional MRI features’ predictability on survival outcome and associations with differentially expressed Genes (RNA Sequencing) in groups of glioblastoma multiforme (GBM) patients.

Methods

Radiomics features were extracted from segmented lesions of T2‐FLAIR MRI data of 137 GBM patients. Radiomics features include intensity, shape and textural features in seven classes were included in the analysis. Patients were divided into two groups depending on their survival time (shorter or longer than 1‐year survival). Four different machine learning algorithms were implemented to construct the prediction models. Features with top importance (importance >0.04) were selected to construct the prediction model using the model with the best performance. The interactions between image features and genomics were then analysed with Pearson's correlation analysis.

Results

The GBDT model with 72 features with highest importance had the highest accuracy of 0.81 on both short and long survival time classes, and the area under the curve (AUC) of the receiver operative characteristic (ROC) of the short and long survival time class were 0.79 and 0.81. Six metagenes showed significant interactive effect (P < 0.05), and Pearson's correlation analysis revealed that three of these metagenes (TIMP1,ROS1 EREG) showed moderate (0.3 < |r| < 0.5) or high correlation (|r| > 0.5) with image features.

Conclusion

Radiogenomics analysis shows that MRI features are predictive of survival outcomes, and image features are highly associated with selective metagenes. Radiogenomics analysis is a useful method for optimizing clinical diagnosis and selecting effective treatments.

Distinct expression and prognostic value of members of the epidermal growth factor receptor family in ovarian cancer

Background

Increased aberrant expression or activation of the epidermal growth factor receptor (EGFR) family members has been reported in a wide range of cancers, and the EGFR family of tyrosine kinases has emerged as an important therapeutic target in malignancies. However, the expression patterns and exact roles of each distinct EGFR family member, which contribute to tumorigenesis and progression of ovarian cancer (OC), are yet to be elucidated.

Materials and methods

In the current study, we report the distinct expression and prognostic value of EGFR family members in patients with OC by analyzing a series of databases including ONCOMINE, Gene Expression Profiling Interactive Analysis, Kaplan-Meier plotter, cBioPortal, and Database for Annotation, Visualization and Integrated Discovery .

Results

It was found that in patients with OC, mRNA expression levels of ERBB2/3/4 were significantly upregulated, whereas the transcription levels of EGFR were downregulated. Aberrant EGFR expression and ERBB2/3/4 mRNA levels were associated with OC prognosis.

Conclusion

These results suggest that EGFR and ERBB3/4 are distinct prognostic biomarkers and may be potential targets for OC. These results may be beneficial to better understand the molecular underpinning of OC and may be useful to develop tools for more accurate OC prognosis and for promoting the development of EGFR-targeted inhibitors for OC treatment.

Functions and mechanisms of microRNA-31 in human cancers

MicroRNAs can exhibit opposite functions in different tumors. MiR-31 is a representative example as it can not only enhance tumor development and progression in pancreatic cancer, colorectal cancer and so on, but also inhibit tumorigenesis and induce apoptosis in ovarian cancer, prostate cancer and etc. The mechanism underlying its' pleiotropy remains unknown. Several recent studies that focused on the global gene expression changes caused by aberrant miR-31 provided information on the upstream and downstream events associated with deregulated miR-31. MiR-31 might interact with a number of signaling pathways including RAS/MARK, PI3K/AKT and RB/E2F to play its opposite functions. This review summarizes the target genes and pathways associated with miR-31 and examines the mechanisms underlying the function of miR-31. The resulting hypothesis is possible that the tissue-specific features of adenocarcinoma and squamous cell cancer and the positive feedback loop consists of miR-31 and its upstream and downstream may account for the diversity of miR-31 functions.

Correlations of EGF G1380A, bFGF C754G and VEGF T460C polymorphisms with malignant melanoma susceptibility and prognosis: A case-control study

This case-control study aims to investigate the correlations of EGF G1380A, bFGF C754G and VEGF T460C polymorphisms with the susceptibility and prognosis of malignant melanoma. A total of 153 patients with multiple primary melanomas were collected as the case group and another 170 healthy individuals were selected as the control group. ELISA and PCR-RFLP were performed to test the serum level of VEGF and to analyze the genotype as well as allele frequencies of VEGF T460C, EGF G1380A, and bFGF C754G, respectively. The patients were assigned into complete remission (CR), partial remission (PR) and non-remission groups after treatment. HE and CD34 staining were conducted in tissue samples of CR and PR patients. Event-free survival (EFS) and overall survival (OS) were measured. AA genotype of EGF G1380A and GG genotype of bFGF C754G had higher frequency distribution in the case group than the control group. Patients with AA genotype of EGF G1380 and GG genotype of bFGF C754G had an elevated VEGF level in comparison to other genotypes. Patients with GA+GG genotypes of EGF G1380A and CG+CC genotypes of bFGF C754G had higher EFS and OS than those with AA genotype and those with GG genotype, respectively. According to the haplotype analysis, the case group had a notably higher frequency of TAG and CAG along with while lower frequency of TGG and CGC compared with the control group. Logistic regression analysis revealed that the polymorphisms of EGF G1380A and bFGF C754G as well as the haploid TAG increased the susceptibility of malignant melanoma. The results indicated that EGF G1380A and bFGF C754G gene polymorphisms were associated with the susceptibility and prognosis of malignant melanoma, and that the polymorphisms of EGF G1380A and bFGF C754G as well as the haploid TAG increased the susceptibility of malignant melanoma.

Influence of the HER receptor ligand system on sensitivity to cetuximab and trastuzumab in gastric cancer cell lines

Purpose

Gastric cancer remains a major health concern, and improvement of the therapeutic options is crucial. Treatment with targeted therapeutics such as the EGFR-targeting antibody cetuximab or the HER2-targeting antibody trastuzumab is either ineffective or moderately effective in this disease, respectively. In this study, we analysed the involvement of the HER receptor ligands amphiregulin (AREG), epidermal growth factor (EGF), heparin-binding epidermal growth factor (HB-EGF) and transforming growth factor alpha (TGFα) in the responsiveness of gastric cancer cell lines to cetuximab and trastuzumab.

Methods

A panel of 11 gastric cancer cell lines was characterized for cetuximab and trastuzumab sensitivity, ligand secretion and expression and activation of the HER receptors using WST-1 cell proliferation assays, ELISAs and Western blot analyses. We further investigated the effects of an exogenous ligand application on the cetuximab and trastuzumab sensitivity.

Results

We found no correlation between TGFα secretion and the sensitivity to cetuximab or trastuzumab. For AREG, we confirmed previous results indicating that this ligand is a positive predictor of cetuximab sensitivity. Exogenous HB-EGF was effective in rescuing sensitive cell lines from inhibition of cell proliferation by both, cetuximab and trastuzumab.

Conclusions

Our data indicate that HB-EGF may be a useful marker for the prediction of trastuzumab sensitivity in gastric cancer.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2308-z) contains supplementary material, which is available to authorized users.

HER3, but Not HER4, Plays an Essential Role in the Clinicopathology and Prognosis of Gastric Cancer: A Meta-Analysis

Background and Aim

Human epidermal growth factor receptor (HER) family plays an important role in gastric cancer (GC), especially HER2. Too much attention has been paid to HER2; however, the functions of HER3 and HER4 overexpression in GC are always ignored. The clinicopathological and prognostic roles of HER3 and HER4 in GC are controversial. In this study, a systematic review and meta-analysis was conducted to evaluate the use of HER3 or HER4 as a predictor of clinicopathology and survival time in GC patients.

Methods

Eligible studies were searched on PubMed, Ovid, Web of Science, and Cochrane databases through multiple search strategies. Data collection and statistical analysis were carried out by the Revman 5.3 software. The Newcastle-Ottawa scale was used to assess the quality of included studies.

Results

A total of 448 studies about HER3 overexpression and GC, and 398 studies about HER4 overexpression and GC were searched. Of these, 5 eligible studies about HER3 including 1016 GC patients and 3 eligible studies about HER4 including 793 GC patients met the inclusion criteria. The results showed that HER3 and HER4 overexpression were significantly associated with depth of tumor invasion (OR = 0.44, 95%CI 0.29–0.67, P = 0.0002 and OR = 0.50, 95%CI 0.38–0.86, P = 0.007) and lymph node metastasis (OR = 0.40, 95%CI 0.20–0.77, P = 0.007 and OR = 0.57, 95%CI 0.38–0.86, P = 0.007), and HER3 overexpression reveals a tendency of later tumor node metastases (TNM) stage (OR = 0.50, 95%CI 0.22–1.15, P = 0.10) and predicts a worse survival time (RR = 0.71, 95%CI 0.61–0.84, P<0.00001), while HER4 overexpression had no correlation with TNM stage (OR = 0.60, 95%CI 0.20–1.78) and survival time (RR = 1.09, 95%CI 0.91–1.30).

Conclusions

This meta-analysis indicated that HER3 plays an essential role in the clinicopathology and prognosis of GC. However, HER4 may not be an ideal prognostic factor for GC.

Preventing High Fat Diet-induced Obesity and Improving Insulin Sensitivity through Neuregulin 4 Gene Transfer

Neuregulin 4 (NRG4), an epidermal growth factor-like signaling molecule, plays an important role in cell-to-cell communication during tissue development. Its function to regulate energy metabolism has recently been reported. This current study was designed to assess the preventive and therapeutic effects of NRG4 overexpression on high fat diet (HFD)-induced obesity. Using the hydrodynamic gene transfer method, we demonstrate that Nrg4 gene transfer in mice suppressed the development of diet-induced obesity, but did not affect pre-existing adiposity and body weight in obese mice. Nrg4 gene transfer curbed HFD-induced hepatic steatosis by inhibiting lipogenesis and PPARγ-mediated lipid storage. Concurrently, overexpression of NRG4 reduced chronic inflammation in both preventive and treatment studies, evidenced by lower mRNA levels of macrophage marker genes including F4/80, Cd68, Cd11b, Cd11c, and macrophage chemokine Mcp1, resulting in improved insulin sensitivity. Collectively, these results demonstrate that overexpression of the Nrg4 gene by hydrodynamic gene delivery prevents HFD-induced weight gain and fatty liver, alleviates obesity-induced chronic inflammation and insulin resistance, and supports the health benefits of NRG4 in managing obesity and obesity-associated metabolic disorders.

Nucleostemin regulates proliferation and migration of gastric cancer and correlates with its malignancy

OBJECTIVE

The aim of this study was to investigate the effects of nucleostemin (NS) knocking down in SGC- 7901 gastric cancer cell line and investigates its correlation with the metastasis and TNM stage ingastric cancer (GC) patients.

METHODS

NS expression was assessed using immunohistochemistry in 421 patients with GC. The correlation between NS expression, clinicopathological features and prognosis was analyzed. NS gene silencing was performed using a specific small interfering RNA (NS-siRNA). The gene expression level of NS was evaluated by PCR. The viability and growth rate of SGC-7901 cells were determined by trypan blue exclusion test. Cell cycle distribution of the cells was analyzed by flow cytometry.

RESULTS

High NS expression was correlated with node metastasis, distant metastasis and TNM stage. Kaplan-Meier survival analysis revealed that patients with low NS expression had significantly longer survival than those with high NS expression. Moreover, our results showed that NS knocking down inhibited proliferation and viability of SGC-7901 cells in a time-dependent manner. Cell cycle studies revealed that NS depletion resulted in G1 cell cycle arrest at short times of transfection (24 h) followed with apoptosis at longer times (48 and 72 h), suggest that post-G1 arrest apoptosis is occurred in SGC-7901 cells.

CONCLUSION

Overall, these results point to essential role of NS in SGC-7901 cells, thus, this gene might be considered as a promising target for treatment of GC.

MicroRNA-126 regulates migration and invasion of gastric cancer by targeting CADM1

OBJECTIVE

The aberrant expression of microRNAs has been demonstrated to play a crucial role in the initiation and progression of gastric cancer (GC). We here aimed to investigate the mechanism of microRNAs in the regulation of GC pathogenesis.

METHODS

Transwell chambers (8-μM pore size; Costar) were used in the in vitro migration and in vision assay. Dual luciferase reporter gene construct and dual luciferase reporter assay to identify the target of miR-126. CADM1 expression was evaluated by immunohistochemical staining. The clinical manifestations, treatments and survival were collected for statistical analysis.

RESULTS

Inhibition of miR-126 effectively reduced migration and invasion of gastric cancer cell lines. Bioinformatics and luciferase reporter assay revealed that miR-126 specifically targeted the 3'UTR of cell adhesion molecule 1 (CADM1) and regulated its expression. Down-regulation of CADM1 enhanced migration and invasion of GC cell lines. Furthermore, in tumor tissues obtained from gastric cancer patients, the expression of miR-126 was negatively correlated with CADM1 and the high expression of miR-126 combined with low expression of CADM1 might serve as a risk factor for stage1 gastric cancer patients.

CONCLUSIONS

Our study showed that miR-126, by down-regulation CADM1, enhances migration and invasion in GC cells.

Protein expression of HER2, 3, 4 in gastric cancer: correlation with clinical features and survival

BACKGROUND AND AIMS

Despite significant improvements in targeted therapies for patients with advanced gastric cancer (GC), the prognosis of those patients remains poor. This study explores the expression and clinicopathological significance of human epidermal growth factor receptor 2, 3 and 4 (HER2, HER3, HER4) in GC, in order to find more prognostic biomarkers of GC and putative targets of therapy.

METHODS

Immunohistochemistry was performed for HER2, HER3 and HER4 in 498 patients with GC using tissue microarray. Correlations between the receptor expression and clinicopathological features, as well as prognosis of the patients were statistically analysed.

RESULTS

The high expression rates of HER2, HER3 and HER4 proteins in the patients were 8.6% (43/498), 20.7% (103/498) and 13.3% (66/498), respectively. High expression of HER2 and HER3 was correlated with proximal GC of the cardia (p<0.05). High expression of HER3 was associated with the tumour depth, tumour node metastasis (TNM) stage and lymph node metastasis (p<0.05). High expression of HER4 was associated with TNM stage (p<0.05) only. According to a regression model, high expression of HER3 was significantly associated with patients' poor survival (p=0.004). High expression rates of HER2, HER3 and HER4 were correlated with each other, but they were all associated merely with histologically intestinal-type adenocarcinoma of GC (p<0.05).

CONCLUSIONS

HER3 is correlated with the malignant biological behaviour of GC. Expression of HER3 is a significant predictor of poor survival in GC. Therefore, the development of HER3-targeted agents may provide new possibilities in the treatment of GC.

MicroRNA let-7b suppresses human gastric cancer malignancy by targeting ING1

MicroRNAs (miRNAs) are important regulators that play key roles in tumorigenesis and tumor progression. In this study, we investigate whether let-7b acts as a tumor suppressor to inhibit invasion and metastasis in gastric cancers. We analyzed the expression of let-7b in 60 pair-matched gastric neoplastic and adjacent non-neoplastic tissues by quantitative real-time polymerase chain reaction. Functional analysis of let-7b expression was assessed in vitro in gastric cancer cell lines with let-7b precursor and inhibitor. The roles of let-7b in tumorigenesis and tumor metastasis were analyzed using a stable let-7b expression plasmid in nude mice. A luciferase reporter assay was used to assess the effect of let-7b on inhibitor of growth family, member 1 (ING1) expression. Real-time PCR showed decreased levels of let-7b expression in metastatic gastric cancer tissues and cell lines that are potentially highly metastatic. Cell invasion and migration were significantly impaired in GC9811-P and SGC7901-M cell lines after transfection with let-7b mimics. Nude mice with xenograft models of gastric cancer confirmed that let-7b could inhibit gastric cancer metastasis in vivo after transfection by the lentivirus pGCsil-GFP- let-7b. Luciferase reporter assays demonstrated that let-7b directly binds to the 3'-UTR of ING1, and real-time PCR and western blotting further indicated that let-7b downregulated the expression of ING1 at the mRNA and protein levels. Our study demonstrates that overexpression of let-7b in gastric cancer can inhibit invasion and migration of gastric cancer cells through directly targeting the tumor metastasis-associated gene ING1. These findings help clarify the molecular mechanisms involved in gastric cancer metastasis and indicate that let-7b modulation may be a bona fide treatment of gastric cancer.

Knockdown of EGFR inhibits growth and invasion of gastric cancer cells

The epidermal growth factor receptor (EGFR) is an oncogenic trans-membranous receptor, which is overexpressed in multiple human cancers. However, the role of EGFR in gastric cancer (GC) is still elusive. In this study, we aimed to investigate the expression and molecular mechanisms of EGFR in GC cells. Forty cases of GC and the corresponding adjacent non-cancerous tissues (ANCT) were collected, and the expression of EGFR was assessed using immunohistochemistry in biopsy samples. Furthermore, EGFR signaling was blocked by constructed recombinant small hairpin RNA lentiviral vector (Lv-shRAGE) used to transfect into human GC SGC-7901 cells. The expression of AKT, proliferating cell nuclear antigen (PCNA) and matrix metallopeptidase-9 (MMP-9) was detected by real-time PCR and western blotting assays. Cell proliferative activities and invasive capability were, respectively, determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) and Transwell assays. Cell apoptosis and cycle distribution were analyzed by flow cytometry. EGFR was found highly expressed in cancer tissues compared with the ANCT and correlated with lymph node metastases. Knockdown of EGFR reduced cell proliferation and invasion of GC with decreased expression of AKT, PCNA and MMP-9 and induced cell apoptosis and cycle arrest. Upregulation of EGFR expression is associated with lymph node metastases of GC, and blockade of EGFR signaling suppresses growth and invasion of GC cells through AKT pathway, suggesting that EGFR may represent a potential therapeutic target for this aggressive malignancy.

Dipeptidyl peptidase IV as a potential target for selective prodrug activation and chemotherapeutic action in cancers

The efficacy of chemotherapeutic drugs is often offset by severe side effects attributable to poor selectivity and toxicity to normal cells. Recently, the enzyme dipeptidyl peptidase IV (DPPIV) was considered as a potential target for the delivery of chemotherapeutic drugs. The purpose of this study was to investigate the feasibility of targeting chemotherapeutic drugs to DPPIV as a strategy to enhance their specificity. The expression profile of DPPIV was obtained for seven cancer cell lines using DNA microarray data from the DTP database, and was validated by RT-PCR. A prodrug was then synthesized by linking the cytotoxic drug melphalan to a proline-glycine dipeptide moiety, followed by hydrolysis studies in the seven cell lines with a standard substrate, as well as the glycyl-prolyl-melphalan (GP-Mel). Lastly, cell proliferation studies were carried out to demonstrate enzyme-dependent activation of the candidate prodrug. The relative RT-PCR expression levels of DPPIV in the cancer cell lines exhibited linear correlation with U95Av2 Affymetrix data (r(2) = 0.94), and with specific activity of a standard substrate, glycine-proline-p-nitroanilide (r(2) = 0.96). The significantly higher antiproliferative activity of GP-Mel in Caco-2 cells (GI₅₀ = 261 μM) compared to that in SK-MEL-5 cells (GI₅₀ = 807 μM) was consistent with the 9-fold higher specific activity of the prodrug in Caco-2 cells (5.14 pmol/min/μg protein) compared to SK-MEL-5 cells (0.68 pmol/min/μg protein) and with DPPIV expression levels in these cells. Our results demonstrate the great potential to exploit DPPIV as a prodrug activating enzyme for efficient chemotherapeutic drug targeting.