Neuromedin U is overexpressed in pancreatic cancer and increases invasiveness via the hepatocyte growth factor c-Met pathway

The peptide neuromedin U (NMU) is elevated in NYHA II and III heart failure

AIMS

Currently, there is no reliable biomarker to detect pre-heart failure in humans. An early risk signal is an elevated left atrial pressure (LAP) and preliminary results from animal studies strongly suggest the neuropeptide neuromedin U (NMU) is released in response to this increase in LAP. However, it is unknown whether NMU is elevated in patients with heart failure. Therefore, the aim of this study was to assess if NMU levels are elevated in human cases of heart failure.

METHODS AND RESULTS

Twenty-four serum samples were obtained from patients in stage II and III heart failure from the Royal Papworth Hospital in Cambridge UK and tested using a selective NMU-ELISA; the data were compared with serum obtained commercially from self-declared healthy donors. NMU concentrations in serum from heart failure patients were significantly higher (P = 0.0007; unpaired Student's t-test) than control, 8.48 ± 0.67 ng/mL (mean ± SEM) versus 5.43 ± 0.46 ng/mL. There was no significant difference between NYHA stage II and III patients (P = 0.85, unpaired Student's t-test), which were 8.33 ± 0.89 ng/mL (n = 9) and 8.6 ± 0.95 ng/mL (n = 15), respectively. Only mean right atrial pressure was found to have a significant correlation with serum NMU (R = 0.81, P < 0.00001; regression analysis).

CONCLUSIONS

NMU is elevated in serum from stage II and III heart failure patients, supporting data from our pre-heart failure animal model; however, further study is needed to determine whether NMU is a reliable biomarker for pre-heart failure.

Identification of Prognostic Markers of DNA Damage and Oxidative Stress in Diagnosing Papillary Renal Cell Carcinoma Based on High-Throughput Bioinformatics Screening

Purpose

Papillary renal cell carcinoma (pRCC) is the second most common histological subtype of adult kidney tumors, with a poor prognosis due to limited understanding of the disease mechanism. Herein, we have performed high-throughput bioinformatic screening to explore and identify potential biomarkers of DNA damage and oxidative stress for pRCC.

Methods

RNA sequencing data related to pRCC were downloaded from the TCGA database, and differentially expressed genes (DEG) were identified by a wide variety of clustering and classification algorithms, including self-organized maps (SOM), artificial neural networks (ANN), support vector machines (SVM), fuzzy logic, and hyphenated techniques such as neuro-fuzzy networks. Then DAVID and STRING online biological information tools were used to analyze functional enrichment of the regulatory networks of DEG and construct a protein-protein interaction (PPI) network, and then the Cytoscape software was used to identify hub genes. The importance of key genes was assessed by the analysis of the Kaplan-Meier survival curves using the R software. Lastly, we have analyzed the expression of hub genes of DNA damage and oxidative stress (BDKRB1, NMUR2, PMCH, and SAA1) in pRCC tissues and adjacent normal tissues, as well as the relationship between the expression of hub genes in pRCC tissues and pathological characteristics and prognosis of pRCC patients.

Results

A total of 1,992 DEGs for pRCC were identified, with 1,142 upregulated ones and 850 downregulated ones. The DEGs were significantly enriched in activities including DNA damage and oxidative stress, chemical synaptic transmission, an integral component of the membrane, calcium ion binding, and neuroactive ligand-receptor interaction. cytoHubba in the Cytoscape software was used to determine the top 10 hub genes in the PPI network as BDKRB2, NMUR2, NMU, BDKRB1, LPAR5, KNG1, LPAR3, SAA1, MCHR1, PMCH, and NCAPH. Furthermore, the expression level of hub genes BDKRB1, NMUR2, PMCH, and SAA1 in pRCC tissues was significantly higher than that in the adjacent normal tissues. Meanwhile, the expression level of hub genes BDKRB1, NMUR2, PMCH, and SAA1 in pRCC tissues was significantly positively correlated with tumor stage, lymph node metastasis, and the histopathology grade of pRCC. In addition, high expression levels of hub genes BDKRB1, NMUR2, PMCH, and SAA1 were associated with a poor prognosis for patients with pRCC. Univariate and multivariate analyses showed that the expression of hub genes BDKRB1, NMUR2, PMCH, and SAA1 were independent risk factors for the prognosis of patients with pRCC.

Conclusion

The results of this analysis suggested that BDKRB1, NMUR2, PMCH, and SAA1 might be potential prognostic biomarkers and novel therapeutic targets for pRCC.

Imaging strategies for receptor tyrosine kinase dimers in living cells

Receptor tyrosine kinases (RTKs) are the essential regulators of cell signal transduction pathways and play important roles in biological processes. RTK dimerization is generally considered the first step in receptor activation and cell communication. And the abnormal expression of RTK dimers is closely related to the occurrence and development of many diseases. Therefore, the visualization of RTK dimerization is of great significance for monitoring physiological processes. The genetic and nongenetic imaging strategies have attracted widespread attention due to their high efficiency and high sensitivity. In this review, the RTKs and their dimers as well as the advances in strategies for imaging RTK dimers are introduced. Furthermore, we analyze the limitations of existing imaging strategies and put forward suggestions for the future development of imaging probes. We expect that this review will inspire more in-depth investigation of RTK dimers, which will also broaden the application of strategies of RTK dimers in biomedical areas.

Insights Into the Research Status of Neuromedin U: A Bibliometric and Visual Analysis From 1987 to 2021

Neuromedin U (NMU) is a regulatory peptide that is widely distributed throughout the body and performs a variety of physiological functions through its corresponding receptors. In recent years, NMU has become the focus of attention in various fields of research as its diverse and essential functions have gradually been elucidated. However, there have been no bibliometrics studies on the development trend and knowledge structure of NMU research. Therefore, in this study, we used VOSviewer software to statistically analyze scientific data from articles related to NMU to track the developmental footprint of this research field, including relevant countries, institutions, authors, and keywords. We retrieved a total of 338 papers related to NMU, written by 1,661 authors from 438 organizations of 41 countries that were published in 332 journals. The first study on NMU was reported by a group in Japan in 1985. Subsequently, nine articles on NMU were published from 1987 to 2006. A small leap in this field could be detected in 2009, with 30 articles published worldwide. Among the various countries in which this research has been performed, Japan and the United States have made the most outstanding contributions. Miyazato M, Kangawa K, and Mori K from the Department of Biochemistry, National Retrain and Cardiovascular Center Research Institute in Japan were the most productive authors who have the highest number of citations. Keyword analysis showed six clusters: central-nervous-system, homeostasis, energy metabolism, cancer, immune inflammation, and food intake. The three most highly cited articles were associated with inflammation. Overall, this study demonstrates the research trends and future directions of NMU, providing an objective description of the contributions in this field along with reference value for future research.

Neuromedin U induces an invasive phenotype in CRC cells expressing the NMUR2 receptor

Background

Successful colorectal cancer (CRC) therapy often depends on the accurate identification of primary tumours with invasive potential. There is still a lack of identified pathological factors associated with disease recurrence that could help in making treatment decisions. Neuromedin U (NMU) is a secretory neuropeptide that was first isolated from the porcine spinal cord, and it has emerged as a novel factor involved in the tumorigenesis and/or metastasis of many types of cancers. Previously associated with processes leading to CRC cell invasiveness, NMU has the potential to be a marker of poor outcome, but it has not been extensively studied in CRC.

Methods

Data from The Cancer Genome Atlas (TCGA) were used to analyse NMU and NMU receptor (NMUR1 and NMUR2) expression in CRC tissues vs. normal tissues, and real-time PCR was used for NMU and NMU receptor expression analysis. NMU protein detection was performed by immunoblotting. Secreted NMU was immunoprecipitated from cell culture-conditioned media and analysed by immunoblotting and protein sequencing. DNA demethylation by 5-aza-CdR was used to analyse the regulation of NMUR1 and NMUR2 expression. NMU receptor activity was monitored by detecting calcium mobilisation in cells loaded with fluo-4, and ERK1/2 kinase activation was detected after treatment with NMU or receptor agonist. Cell migration and invasion were investigated using membrane filters. Integrin expression was evaluated by flow cytometry.

Results

The obtained data revealed elevated expression of NMU and NMUR2 in CRC tissue samples and variable expression in the analysed CRC cell lines. We have shown, for the first time, that NMUR2 activation induces signalling in CRC cells and that NMU increases the motility and invasiveness of NMUR2-positive CRC cells and increases prometastatic integrin receptor subunit expression.

Conclusions

Our results show the ability of CRC cells to respond to NMU via activation of the NMUR2 receptor, which ultimately leads to a shift in the CRC phenotype towards a more invasive phenotype.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02073-8.

Systems Biology Integration and Screening of Reliable Prognostic Markers to Create Synergies in the Control of Lung Cancer Patients

This study aims to achieve a clearer and stronger understanding of all the mechanisms involved in the occurrence as well as in the progression of lung cancer along with discovering trustworthy prognostic markers. We combined four gene expression profiles (GSE19188, GSE19804, GSE101929, and GSE18842) from the GEO database and screened the commonly differentially expressed genes (CDEGs). We performed differentially expressed group analysis on CDEGs, alteration and mutational analysis, and expression level verification of core differential genes. Systems biology discoveries in our examination are predictable with past reports. Curiously, our examination revealed that screened biomarker adjustments, for the most part, coexist in lung cancer. After screening 952 CDEGs, we found that the up-regulation of neuromedin U (NMU) and GTSE1 in the case of lung cancer is related to poor prognosis. On the other hand, FOS CDKN1C expression is associated with poor prognosis and is responsible for the down-regulation of CDKN1C and FOS. Changes in these qualities are on free pathways to lung cancer and are not usually of combined quality variety. Even though biomarkers were related to both survival occasions in our examination, it gives us another point of view while playing out the investigation of hereditary changes and clinical highlights employing information mining. Based on our results, we found potential and prospective clinical applications in GTSE1, NMU, FOS, and CDKN1C to act as prognostic markers in case of lung cancer.

The prognostic value of neuromedin U in patients with hepatocellular carcinoma

Background

Neuromedin U (NMU) is a neuropeptide belonging to the neuromedin family. Recently, significant associations between NMU and several cancers have been reported. However, no studies have examined the association between NMU and hepatocellular carcinoma (HCC). The purpose of this study was to examine the role of NMU in HCC.

Methods

An enzyme-linked immunosorbent assay was used to measure the level of NMU protein in the sera of patients with hepatic hemangioma and HCC. NMU and cytokine mRNA expression was assessed in HCC samples via RT-qPCR. A tissue microarray consisting of 228 HCC peri- and intra-tumor tissues was used to detect NMU expression via immunohistochemical analysis. The association between NMU expression and overall survival (OS) and disease-free survival (DFS) was analyzed by Kaplan-Meier curves, the log-rank test, and Cox proportional hazard model.

Results

The level of NMU protein was increased in the sera of HCC patients (p = 0.006). NMU was expressed in intercellular space, rather than in hepatocytes or HCC cells. The prognosis of HCC patients with high NMU expression in peri-tumor tissue was significantly poorer than that of patients with low NMU expression (OS: p = 0.002, DFS: p = 0.033). Peri-tumor NMU expression was also a significant independent prognostic factor for OS (hazard ratio: 1.541, 95% confidence interval: 1.092–2.175, p = 0.014). The level of NMU expression was positively associated with M2 macrophage percentage and the levels of type-2 inflammatory cytokines in HCC tissue.

Conclusions

NMU may serve as a novel prognostic biomarker for HCC patients, although further validation is needed in the future. The activation of M2 macrophages and a type-2 inflammatory response may involve in the role of NMU in patients with HCC.

Two Receptors, Two Isoforms, Two Cancers: Comprehensive Analysis of KIT and TrkA Expression in Neuroblastoma and Acute Myeloid Leukemia

Pediatric cancers represent a wide variety of different tumors, though they have unique features that distinguish them from adult cancers. Receptor tyrosine kinases KIT and TrkA functions in AML and NB, respectively, are well-characterized. Though expression of these receptors is found in both tumors, little is known about KIT function in NB and TrkA in AML. By combining gene enrichment analysis with multidimensional scaling we showed that pediatric AMLs with t(8;21) or inv16 and high KIT expression levels stand out from other AML subtypes as they share prominent transcriptomic features exclusively with KIT-overexpressing NBs. We showed that AML cell lines had a predominant expression of an alternative TrkAIII isoform, which reportedly has oncogenic features, while NB cell lines had dominating TrkAI-II isoforms. NB cells, on the other hand, had an abnormal ratio of KIT isoforms as opposed to AML cells. Both SCF and NGF exerted protective action against doxorubicin and cytarabine for t(8;21) AML and NB cells. We identified several gene sets both unique and common for pediatric AML and NB, and this expression is associated with KIT or TrkA levels. NMU, DUSP4, RET, SUSD5, NOS1, and GABRA5 genes are differentially expressed in NBs with high KIT expression and are associated with poor survival in NB. We identified HOXA10, BAG3, and MARCKS genes that are connected with TrkA expression and are marker genes of poor outcome in AML. We also report that SLC18A2, PLXNC1, and MRPL33 gene expression is associated with TrkA or KIT expression levels in both AML and NB, and these genes have a prognostic value for both cancers. Thus, we have provided a comprehensive characterization of TrkA and KIT expression along with the oncogenic signatures of these genes across two pediatric tumors.

The YAP1-NMU Axis Is Associated with Pancreatic Cancer Progression and Poor Outcome: Identification of a Novel Diagnostic Biomarker and Therapeutic Target

Yes-associated protein (YAP)-1 is highly upregulated in pancreatic cancer and associated with tumor progression. However, little is known about the role of YAP1 and related genes in pancreatic cancer. Here, we identified target genes regulated by YAP1 and explored their role in pancreatic cancer progression and the related clinical implications. Analysis of different pancreatic cancer databases showed that Neuromedin U (NMU) expression was positively correlated with YAP1 expression in the tumor group. The Cancer Genome Atlas data indicated that high YAP1 and NMU expression levels were associated with poor mean and overall survival. YAP1 overexpression induced NMU expression and transcription and promoted cell motility in vitro and tumor metastasis in vivo via upregulation of epithelial-mesenchymal transition (EMT), whereas specific inhibition of NMU in cells stably expressing YAP1 had the opposite effect in vitro and in vivo. To define this functional association, we identified a transcriptional enhanced associate domain (TEAD) binding site in the NMU promoter and demonstrated that YAP1-TEAD binding upstream of the NMU gene regulated its transcription. These results indicate that the identified positive correlation between YAP1 and NMU is a potential novel drug target and biomarker in metastatic pancreatic cancer.

Neuromedin U: A Small Peptide in the Big World of Cancer

Neuromedin U (NMU), a neuropeptide isolated from porcine spinal cord and named because of its activity as a rat uterus smooth muscle contraction inducer, is emerging as a new player in the tumorigenesis and/or metastasis of many types of cancers. Expressed in a variety of tissues, NMU has been shown to possess many important activities in the central nervous system as well as on the periphery. Along with the main structural and functional features of NMU and its currently known receptors, we summarized a growing number of recently published data from different tissues and cells that associate NMU activity with cancer development and progression. We ask if, based on current reports, NMU can be included as a marker of these processes and/or considered as a therapeutic target.

Pancreatic Stellate Cells Facilitate Perineural Invasion of Pancreatic Cancer via HGF/c-Met Pathway

Pancreatic cancer (PC) is a highly lethal cancer that has a strong ability for invasion and metastasis, poor prognosis, and a stubbornly high death rate due to late diagnosis and early metastasis. Therefore, a better understanding of the mechanisms of metastasis should provide novel opportunities for therapeutic purposes. As a route of metastasis in PC, perineural invasion (PNI) occurs frequently; however, the molecular mechanism of PNI is still poorly understood. In this study, we show that the hepatocyte growth factor (HGF)/c-Met pathway plays a vital role in the PNI of PC. We found that HGF promotes PC cell migration and invasion by activating the HGF/c-Met pathway, and enhances the expression of nerve growth factor (NGF) and matrix metalloproteinase-9 (MMP9) in vitro. Furthermore, HGF significantly increased PC cell invasion of the dorsal root ganglia (DRG) and promoted the outgrowth of DRG in cocultured models of PC cells and DRG. In contrast, the capacity for invasion and the phenomenon of PNI in PC cells were reduced when the HGF/c-Met pathway was blocked by siRNA. In conclusion, PSCs facilitate PC cell PNI via the HGF/c-Met pathway. Targeting the HGF/c-Met signaling pathway could be a promising therapeutic strategy for PC.

Circulating neuromedin U levels are similar in subjects with NGT and newly diagnosed T2DM and do not correlate with insulin secretion

AIMS

Neuromedin U (NMU), a highly conserved peptide, is implicated in energy homeostasis and is involved in regulating insulin secretion as a decretin hormone in animals. However, there have been no reports on the relationship between NMU and type 2 diabetes mellitus (T2DM). The aim of this study was to investigate circulating NMU concentrations in healthy subjects and T2DM patients and to evaluate the association between serum NMU levels and glucose-stimulated insulin secretion.

METHODS

We used ELISA to analyze NMU concentrations in blood samples from newly diagnosed T2DM patients (n = 57) and age-, sex- and BMI-matched healthy control subjects (n = 50). Anthropometric parameters, oral glucose tolerance, glycosylated hemoglobin, blood lipids, insulin sensitivity, and insulin secretion were measured.

RESULTS

No difference was observed in serum NMU levels between control subjects and newly diagnosed T2DM patients (p = 0.788). The oral glucose tolerance test (OGTT) results indicated that serum NMU concentrations did not change and did not correlate with insulin levels at fasting and 1 h, 2 h and 3 h after glucose load in both healthy controls and newly diagnosed T2DM patients.

CONCLUSION

Circulating NMU concentrations were similar in control subjects and newly diagnosed T2DM patients and were not associated with glucose-stimulated insulin secretion. Serum NMU is not a human decretin hormone and may not play a role in the pathogenesis of T2DM.

Genetic expression profile-based screening of genes and pathways associated with papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid cancer; however, the specific genes and signaling pathways involved in this cancer remain largely unclear. The present study analyzed three profile datasets, GSE6004, GSE29265 and GSE60542, which were comprised of 47 PTC and 41 normal thyroid tissue samples, to identify key genes and pathways associated with PTC. Initially, differentially-expressed genes (DEGs) between PTC and normal thyroid tissue were screened using R 3.4.0 (2017-04-21, R Foundation, Vienna, Austria, http://www.R-project.org/). These DEGs were then clustered by gene ontology functional terms and representative signaling pathways. Additionally, specific key gene nodes were filtered out from a constructed protein-protein interaction (PPI) network. The results identified a total of 423 shared DEGs associated with PTC, including 211 upregulated and 212 downregulated genes. These 423 genes were primarily enriched in glycosaminoglycan binding, sulfur compound binding, heparin binding, enzyme activator activity, peptidase activator activity and hsa04512: Extracellular matrix (ECM)-receptor interaction. A total of 21 central node genes were identified as key genes in the PTC disease process including complement factor D (CFD), Collagen Type I α 1 Chain (COL1A1), Extracellular Matrix Protein 1 (ECM1) and Fibronectin 1 (FN1). These genes are involved in protease binding, G-protein coupled receptor binding, extracellular matrix structural constituent and peptidase regulator activity. To conclude, using bioinformatics analysis, the present study identified candidate DEGs and critical pathways in PTC that may improve the current understanding regarding the underlying mechanisms of PTC. These genes and pathways may be used as potential therapeutic targets of PTC in the future.

Pancreatic-cancer-cell-derived trefoil factor 2 impairs maturation and migration of human monocyte-derived dendritic cells in vitro

Pancreatic cancer is a challenging disease with a high mortality rate. While the importance of crosstalk between cancer and immune cells has been well documented, the understanding of this complex molecular network is incomplete. Thus, identification of the secreted proteins contributing to the immunosuppressive microenvironment in pancreatic cancer is crucial for effective diagnosis and/or therapy. We utilized a public microarray dataset (GSE16515) from the Gene Expression Omnibus database to identify genes for secreted proteins in pancreatic cancer. RT-PCR and ELISA of the pancreatic cancer cell lines validated the cellular origin of the selected genes. For functional assay of the selected proteins, we utilized human-monocyte-derived dendritic cells (DCs). From the list of the secreted proteins, trefoil factor 2 (TFF2) was further examined as a potential chemokine/cytokine. While TFF2 did not significantly affect the phenotypic maturation and the allostimulatory capacity of DCs, TFF2 preferentially attracted immature (but not mature) DCs and inhibited their endocytic activity. Our data suggest that TFF2 from pancreatic cancer cells may attract immature DCs and affect the initial stage of DC maturation, thereby contributing to the induction of immune tolerance against pancreatic cancer.

Oncogenic features of neuromedin U in breast cancer are associated with NMUR2 expression involving crosstalk with members of the WNT signaling pathway

Neuromedin U (NMU) has been shown driving the progression of various tumor entities, including breast cancer. However, the expression pattern of NMU and its receptors in breast cancer tissues as well as systematic insight into mechanisms and downstream targets of the NMU-driven signaling pathways are still elusive. Here, NMU expression was found up-regulated in all breast cancer subtypes when compared to healthy breast tissue. Using an in silico dataset comprising 1,195 samples, high NMU expression was identified as an indicator of poor outcome in breast tumors showing strong NMUR2 expression. Next, the biological impact of NMU on breast cancer cells in relation to NMUR2 expression was analyzed. Ectopic NMU expression reduced colony growth while promoting a motile phenotype in NMUR2-positive SKBR3 but not NMUR2-negative Hs578T cells. To uncover signaling pathways and key molecules affected by NMU in SKBR3 cells, Affymetrix microarray analysis was applied. Forced NMU expression affected molecules involved in WNT receptor signaling among others. As such we demonstrated enhanced activation of the WNT/planar cell polarity (PCP) effector RAC1 and down-regulation of canonical WNT targets such as MYC. In summary, NMU might contribute to progression of NMUR2-positive breast cancer representing a potential druggable target for future personalized strategies.

Reconstituting development of pancreatic intraepithelial neoplasia from primary human pancreas duct cells

Development of systems that reconstitute hallmark features of human pancreatic intraepithelial neoplasia (PanINs), the precursor to pancreatic ductal adenocarcinoma, could generate new strategies for early diagnosis and intervention. However, human cell-based PanIN models with defined mutations are unavailable. Here, we report that genetic modification of primary human pancreatic cells leads to development of lesions resembling native human PanINs. Primary human pancreas duct cells harbouring oncogenic KRAS and induced mutations in CDKN2A, SMAD4 and TP53 expand in vitro as epithelial spheres. After pancreatic transplantation, mutant clones form lesions histologically similar to native PanINs, including prominent stromal responses. Gene expression profiling reveals molecular similarities of mutant clones with native PanINs, and identifies potential PanIN biomarker candidates including Neuromedin U, a circulating peptide hormone. Prospective reconstitution of human PanIN development from primary cells provides experimental opportunities to investigate pancreas cancer development, progression and early-stage detection.

Models of human pancreatic intraepithelial neoplasia (PanIN) development do not exist. Here, the authors induce oncogenic KRAS and mutations in CDKN2A, SMAD4 and TP53 in primary human pancreatic cells to generate a PanIN model that recapitulates molecular and pathologic features of native PanINs.

NMU signaling promotes endometrial cancer cell progression by modulating adhesion signaling

Neuromedin U (NMU) was originally named based on its strong uterine contractile activity, but little is known regarding its signaling/functions in utero. We identified that NMU and one of its receptors, NMUR2, are not only present in normal uterine endometrium but also co-expressed in endometrial cancer tissues, where the NMU level is correlated with the malignant grades and survival of patients. Cell-based assays further confirmed that NMU signaling can promote cell motility and proliferation of endometrial cancer cells derived from grade II tumors. Activation of NMU pathway in these endometrial cancer cells is required in order to sustain expression of various adhesion molecules, such as CD44 and integrin alpha1, as well as production of their corresponding extracellular matrix ligands, hyaluronan and collagen IV; it also increased the activity of SRC and its downstream proteins RHOA and RAC1. Thus, it is concluded that NMU pathway positively controls the adhesion signaling-SRC-Rho GTPase axis in the tested endometrial cancer cells and that changes in cell motility and proliferation can occur when there is manipulation of NMU signaling in these cells either in vitro or in vivo. Intriguingly, this novel mechanism also explains how NMU signaling promotes the EGFR-driven and TGFβ receptor-driven mesenchymal transitions. Through the above axis, NMU signaling not only can promote malignancy of the tested endometrial cancer cells directly, but also helps these cells to become more sensitive to niche growth factors in their microenvironment.

Neuromedin U is upregulated by Snail at early stages of EMT in HT29 colon cancer cells

BACKGROUND

The epithelial-mesenchymal transition (EMT) is considered a core process that facilitates the escape of cancer cells from the primary tumor site. The transcription factor Snail was identified as a key regulator of EMT; however, the cascade of regulatory events leading to metastasis remains unknown and new predictive markers of the process are awaited.

METHODS

Gene expressions were analysed using real-time PCR, protein level by Western immunoblotting and confocal imaging. The motility of the cells was examined using time-lapse microscopy. Affymetrix GeneChip Human Genome U133 Plus 2.0 analysis was performed to identify transcriptomic changes upon Snail. Snail silencing was performed using siRNA nucleofection. NMU detection was performed by ELISA.

RESULTS

HT29 cells overexpressing Snail showed changed morphology, functions and transcriptomic profile indicating EMT induction. Changes in expression of 324 genes previously correlated with cell motility were observed. Neuromedin U was the second highest upregulated gene in HT29-Snail cells. This increase was validated by real-time PCR. Additionally elevated NMU protein was detected by ELISA in cell media.

CONCLUSIONS

These results show that Snail in HT29 cells regulates early phenotype conversion towards an intermediate epithelial state. We provided the first evidence that neuromedin U is associated with Snail regulatory function of metastatic induction in colon cancer cells.

GENERAL SIGNIFICANCE

We described the global, early transcriptomic changes induced through Snail in HT29 colon cancer cells and suggested NMU involvement in this process.

miR-1 suppresses the growth of esophageal squamous cell carcinoma in vivo and in vitro through the downregulation of MET, cyclin D1 and CDK4 expression

Several aberrant microRNAs (miRNAs or miRs) have been implicated in esophageal cancer (EC), which is widely prevalent in China. However, their role in EC tumorigenesis has not yet been fully elucidated. In the present study, we determined that miR-1 was downregulated in esophageal squamous cell carcinoma (ESCC) tissues compared with adjacent non-neoplastic tissues using RT-qPCR, and confirmed this using an ESCC cell line. Using a nude mouse xenograft model, we confirmed that the re-expression of miR-1 significantly inhibited ESCC tumor growth. A tetrazolium assay and a trypan blue exclusion assay revealed that miR-1 suppressed ESCC cell proliferation and increased apoptosis, whereas the silencing of miR-1 promoted cell proliferation and decreased apoptosis, suggesting that miR-1 is a novel tumor suppressor. To elucidate the molecular mechanisms of action of miR-1 in ESCC, we investigated putative targets using bioinformatics tools. MET, cyclin D1 and cyclin-dependent kinase 4 (CDK4), which are involved in the hepatocyte growth factor (HGF)/MET signaling pathway, were found to be targets of miR-1. miR-1 expression inversely correlated with MET, cyclin D1 and CDK4 expression in ESCC cells. miR-1 directly targeted MET, cyclin D1 and CDK4, suppressing ESCC cell growth. The newly identified miR-1/MET/cyclin D1/CDK4 axis provides new insight into the molecular mechanisms of ESCC pathogenesis and indicates a novel strategy for the diagnosis and treatment of ESCC.

Overexpression of neuromedin U is correlated with regional metastasis of head and neck squamous cell carcinoma

Regional metastasis is an important prognostic factor for patients with head and neck squamous cell carcinoma (HNSCC). Neuromedin U (Nmu) is a secreted neuropeptide, named due to its potent uterine contraction‑inducing activity. The aim of the present study was to analyze the significance of Nmu in the regional metastasis of HNSCC. The characteristics of 240 patients recruited from the Department of Otolaryngology Head and Neck Surgery, Renmin Hospital of Wuhan University (Wuhan, China) were summarized retrospectively. The positive rate of neck dissection was analyzed according to the material. The expression levels of Nmu in human tumor samples were analyzed using immunohistochemistry. Subsequently, the expression of Nmu was investigated using a tissue microassay to analyze the association between Nmu protein expression and Tumor Node Metastasis (TNM) status. The positive rate of neck dissection was 51.4% in the study sample. The expression levels of Nmu in primary tumors with regional metastasis were higher, compared with those without metastasis. There was increased protein expression of Nmu in the advanced tumor tissues. The data obtained in the present study demonstrated that the expression of Nmu was correlated with regional metastasis and TNM status. Overexpression of Nmu may be involved in the process of regional metastasis of HNSCC, and may serve as a novel and valuable biomarker for predicting regional metastasis in patients with HNSCC.

HGF/Met and FOXM1 form a positive feedback loop and render pancreatic cancer cells resistance to Met inhibition and aggressive phenotypes

Purpose

Hepatocyte growth factor (HGF)/Met signaling plays critical roles in pancreatic ductal adenocarcinoma (PDA) development and progression and is considered a potential therapeutic target for this disease. However, the mechanism of aberrant activation of HGF/Met signaling and resistance to Met inhibition in PDA remains unclear.

Experimental Design

The mechanistic role of cross-talk between Forkhead box M1 (FOXM1) and HGF/Met signaling in promotion of PDA growth and resistance to Met inhibition was examined using cell culture, molecular biology and mouse models; and the relevance of our experimental and mechanistic findings were validated using human PDA tissues.

Results

Met was markedly overexpressed in both PDA cell lines and pancreatic tumor specimens, and the expression of Met correlated directly with that of FOXM1 in human tumor specimens. Mechanistically, FOXM1 bound to the promoter region of the Met gene and transcriptionally increased the expression of Met. Increased expression of FOXM1 enhanced the activation of HGF/Met signaling and its downstream pathways, including RAS/extracellular signal-regulated kinase 1/2, phosphoinositide 3-kinase/AKT, and signal transducer and activator of transcription 3. Furthermore, activation of HGF/Met signaling increased the expression and transcriptional activity of FOXM1, and the cross-talk between FOXM1 and HGF/Met signaling promoted PDA growth and resistance to Met inhibition.

Conclusions

Collectively, our findings identified a positive feedback loop formed by FOXM1 and HGF/Met and revealed that this loop is a potentially effective therapeutic target for PDA.

Identifying a Neuromedin U Receptor 2 Splice Variant and Determining Its Roles in the Regulation of Signaling and Tumorigenesis In Vitro

Neuromedin U (NMU) activates two G protein-coupled receptors, NMUR1 and NMUR2; this signaling not only controls many physiological responses but also promotes tumorigenesis in diverse tissues. We recently identified a novel truncated NMUR2 derived by alternative splicing, namely NMUR2S, from human ovarian cancer cDNA. Sequence analysis, cell surface ELISA and immunocytochemical staining using 293T cells indicated that NMUR2S can be expressed well on the cell surface as a six-transmembrane protein. Receptor pull-down and fluorescent resonance energy transfer assays demonstrated that NMUR1, NMUR2 and this newly discovered NMUR2S can not only form homomeric complexes but also heteromeric complexes with each other. Although not activated by NMU itself, functional assay in combination with receptor quantification and radio-ligand binding in 293T cells indicated that NMUR2S does not alter the translocation and stability of NMUR1 or NMUR2, but rather effectively dampens their signaling by blocking their NMU binding capability through receptor heterodimerization. We further demonstrated that NMU signaling is significantly up-regulated in human ovarian cancers, whereas expression of NMUR2S can block endogenous NMU signaling and further lead to suppression of proliferation in SKOV-3 ovarian cancer cells. In contrast, in monocytic THP-1 cells that express comparable levels of NMUR1 and NMUR2S, depletion of NMUR2S restored both the signaling and effect of NMU. Thus, these results not only reveal the presence of previously uncharacterized heteromeric relationships among NMU receptors but also provide NMUR2S as a potential therapeutic target for the future treatment of NMU signaling-mediated cancers.

Small lipidated anti-obesity compounds derived from neuromedin U

A small library of truncated/lipid-conjugated neuromedin U (NmU) analogs was synthesized and tested in vitro using an intracellular calcium signaling assay. The selected, most active analogs were then tested in vivo, and showed potent anorexigenic effects in a diet-induced obese (DIO) mouse model. The most promising compound, NM4-C16 was effective in a once-weekly-dose regimen. Collectively, our findings suggest that short, lipidated analogs of NmU are suitable leads for the development of novel anti-obesity therapeutics.

Identification of genetic variations of a Chinese family with paramyotonia congenita via whole exome sequencing

Paramyotonia congenita (PC) is a rare autosomal dominant neuromuscular disorder characterized by juvenile onset and development of cold-induced myotonia after repeated activities. The disease is mostly caused by genetic mutations of the sodium channel, voltage-gated, type IV, alpha subunit (SCN4A) gene. This study intended to systematically identify the causative genetic variations of a Chinese Han PC family. Seven members of this PC family, including four patients and three healthy controls, were selected for whole exome sequencing (WES) using the Illumina HiSeq platform. Sequence variations were identified using the SoftGenetics program. The mutation R1448C of SCN4A was found to be the only causative mutation. This study applied WES technology to sequence multiple members of a large PC family and was the first to systematically confirm that the genetic change in SCN4A is the only causative variation in this PC family and the SCN4A mutation is sufficient to lead to PC.

Neuromedin U: a multifunctional neuropeptide with pleiotropic roles

BACKGROUND

Neuromedin U (NmU) belongs to the neuromedin family, comprising a series of neuropeptides involved in the gut-brain axis and including neuromedins B and C (bombesin-like), K (neurokinin B), L (neurokinin A or neurotensin), N, S, and U.

CONTENT

Although initially isolated from porcine spinal cord on the basis of their ability to induce uterine smooth muscle contraction, these peptides have now been found to be expressed in several different tissues and have been ascribed numerous functions, from appetite regulation and energy balance control to muscle contraction and tumor progression. NmU has been detected in several species to date, particularly in mammals (pig, rat, rabbit, dog, guinea pig, human), but also in amphibian, avian, and fish species. The NmU sequence is highly conserved across different species, indicating that this peptide is ancient and plays an important biological role. Here, we summarize the main structural and functional characteristics of NmU and describe its many roles, highlighting the jack-of-all-trades nature of this neuropeptide.

SUMMARY

NmU involvement in key processes has outlined the possibility that this neuropeptide could be a novel target for the treatment of obesity and cancer, among other disorders. Although the potential for NmU as a therapeutic target is obvious, the multiple functions of this molecule should be taken into account when designing an approach to targeting NmU and/or its receptors.

Genetics of breast cancer bone metastasis: a sequential multistep pattern

Bone metastasis accounts for the vast majority of breast cancer (BC) metastases, and is related to a high rate of morbidity and mortality. A number of seminal studies have uncovered gene expression signatures involved in BC development and bone metastasis; each of them points at a distinct step of the 'invasion-metastasis cascade'. In this review, we provide most recently discovered functions of sets of genes that are selected from widely accepted gene signatures that are implicate in BC progression and bone metastasis. We propose a possible sequential pattern of gene expression that may lead a benign primary breast tumor to get aggressiveness and progress toward bone metastasis. A panel of genes which primarily deal with features like DNA replication, survival, proliferation, then, angiogenesis, migration, and invasion has been identified. TGF-β, FGF, NFκB, WNT, PI3K, and JAK-STAT signaling pathways, as the key pathways involved in breast cancer development and metastasis, are evidently regulated by several genes in all three signatures. Epithelial to mesenchymal transition that is also an important mechanism in cancer stem cell generation and metastasis is evidently regulated by these genes. This review provides a comprehensive insight regarding breast cancer bone metastasis that may lead to a better understanding of the disease and take step toward better treatments.

Neuromedin U: a candidate biomarker and therapeutic target to predict and overcome resistance to HER-tyrosine kinase inhibitors

Intrinsic and acquired resistance to HER-targeting drugs occurs in a significant proportion of HER2-overexpressing breast cancers. Thus, there remains a need to identify predictive biomarkers that could improve patient selection and circumvent these types of drug resistance. Here, we report the identification of neuromedin U (NmU) as an extracellular biomarker in cells resistant to HER-targeted drugs. NmU overexpression occurred in cells with acquired or innate resistance to lapatinib, trastuzumab, neratinib, and afatinib, all of which displayed a similar trend upon short-term exposure, suggesting NmU induction may be an early response. An analysis of 3,489 cases of breast cancer showed NmU to be associated with poor patient outcome, particularly those with HER2-overexpressing tumors independent of established prognostic indicators. Ectopic overexpression of NmU in drug-sensitive cells conferred resistance to all HER-targeting drugs, whereas RNAi-mediated attenuation sensitized cells exhibiting acquired or innate drug resistance. Mechanistic investigations suggested that NmU acted through HSP27 as partner protein to stabilize HER2 protein levels. We also obtained evidence of functional NmU receptors on HER2-overexpressing cells, with the addition of exogenous NmU eliciting an elevation in HER2 and EGFR expression along with drug resistance. Finally, we found that NmU seemed to function in cell motility, invasion, and anoikis resistance. In vivo studies revealed that NmU attenuation impaired tumor growth and metastasis. Taken together, our results defined NmU as a candidate drug response biomarker for HER2-overexpressing cancers and as a candidate therapeutic target to limit metastatic progression and improve the efficacy of HER-targeted drugs.

Systems biology approach to stage-wise characterization of epigenetic genes in lung adenocarcinoma

Background

Epigenetics refers to the reversible functional modifications of the genome that do not correlate to changes in the DNA sequence. The aim of this study is to understand DNA methylation patterns across different stages of lung adenocarcinoma (LUAD).

Results

Our study identified 72, 93 and 170 significant DNA methylated genes in Stages I, II and III respectively. A set of common 34 significant DNA methylated genes located in the promoter section of the true CpG islands were found across stages, and these were: HOX genes, FOXG1, GRIK3, HAND2, PRKCB, etc. Of the total significant DNA methylated genes, 65 correlated with transcription function. The epigenetic analysis identified the following novel genes across all stages: PTGDR, TLX3, and POU4F2. The stage-wise analysis observed the appearance of NEUROG1 gene in Stage I and its re-appearance in Stage III. The analysis showed similar epigenetic pattern across Stage I and Stage III. Pathway analysis revealed important signaling and metabolic pathways of LUAD to correlate with epigenetics. Epigenetic subnetwork analysis identified a set of seven conserved genes across all stages: UBC, KRAS, PIK3CA, PIK3R3, RAF1, BRAF, and RAP1A. A detailed literature analysis elucidated epigenetic genes like FOXG1, HLA-G, and NKX6-2 to be known as prognostic targets.

Conclusion

Integrating epigenetic information for genes with expression data can be useful for comprehending in-depth disease mechanism and for the ultimate goal of better target identification.

Acting on Hormone Receptors with Minimal Side Effect on Cell Proliferation: A Timely Challenge Illustrated with GLP-1R and GPER

G protein-coupled receptors (GPCRs) constitute a large family of receptors that sense molecules outside the cell and activate inside signal transduction pathways and cellular responses. GPCR are involved in a wide variety of physiological processes, including in the neuroendocrine system. GPCR are also involved in many diseases and are the target of 30% of marketed medicinal drugs. Whereas the majority of the GPCR-targeting drugs have proved their therapeutic benefit, some of them were associated with undesired effects. We develop two examples of used drugs whose therapeutic benefits are tarnished by carcinogenesis risks. The chronic administration of glucagon-like peptide-1 (GLP-1) analogs widely used to treat type-2 diabetes was associated with an increased risk of pancreatic or thyroid cancers. The long-term treatment with the estrogen antagonist tamoxifen, developed to target breast cancer overexpressing estrogen receptors ER, presents agonist activity on the G protein-coupled estrogen receptor which is associated with an increased incidence of endometrial cancer and breast cancer resistance to hormonotherapy. We point out and discuss the need of pharmacological studies to understand and overcome the undesired effects associated with the chronic administration of GPCR ligands. In fact, biological effects triggered by GPCR often result from the activation of multiple intracellular signaling pathways. Deciphering which signaling networks are engaged following GPCR activation appears to be primordial to unveil their contribution in the physiological and physiopathological processes. The development of biased agonists to elucidate the role of the different signaling mechanisms mediated by GPCR activation will allow the generation of new therapeutic agents with improved efficacy and reduced side effects. In this regard, the identification of GLP-1R biased ligands promoting insulin secretion without inducing pro-tumoral effects would offer therapeutic benefit.

Neuromedins U and S involvement in the regulation of the hypothalamo-pituitary-adrenal axis

We reviewed neuromedin U (NMU) and neuromedin S (NMS) involvement in the regulation of the hypothalamo-pituitary-adrenal (HPA) axis function. NMU and NMS are structurally related and highly conserved neuropeptides. They exert biological effects via two GPCR receptors designated as NMUR1 and NMUR2 which show differential expression. NMUR1 is expressed predominantly at the periphery, while NMUR2 in the central nervous system. Elements of the NMU/NMS and their receptors network are also expressed in the HPA axis and progress in molecular biology techniques provided new information on their actions within this system. Several lines of evidence suggest that within the HPA axis NMU and NMS act at both hypothalamic and adrenal levels. Moreover, new data suggest that NMU and NMS are involved in central and peripheral control of the stress response.

Inactivation of the von Hippel-Lindau tumour suppressor gene induces Neuromedin U expression in renal cancer cells

BACKGROUND

209 000 new cases of renal carcinoma are diagnosed each year worldwide and new therapeutic targets are urgently required. The great majority of clear cell renal cancer involves inactivation of VHL, which acts as a gatekeeper tumour suppressor gene in renal epithelial cells. However how VHL exerts its tumour suppressor function remains unclear. A gene expression microarray comparing RCC10 renal cancer cells expressing either VHL or an empty vector was used to identify novel VHL regulated genes.

FINDINGS

NMU (Neuromedin U) is a neuropeptide that has been implicated in energy homeostasis and tumour progression. Here we show for the first time that VHL loss-of-function results in dramatic upregulation of NMU expression in renal cancer cells. The effect of VHL inactivation was found to be mediated via activation of Hypoxia Inducible Factor (HIF). Exposure of VHL expressing RCC cells to either hypoxia or dimethyloxalylglycine resulted in HIF activation and increased NMU expression. Conversely, suppression of HIF in VHL defective RCC cells via siRNA of HIF-α subunits or expression of Type 2C mutant VHLs reduced NMU expression levels. We also show that renal cancer cells express a functional NMU receptor (NMUR1), and that NMU stimulates migration of renal cancer cells.

CONCLUSIONS

These findings suggest that NMU may act in an autocrine fashion, promoting progression of kidney cancer. Hypoxia and HIF expression are frequently observed in many non-renal cancers and are associated with a poor prognosis. Our study raises the possibility that HIF may also drive NMU expression in non-renal tumours.

AZGP1 is a tumor suppressor in pancreatic cancer inducing mesenchymal-to-epithelial transdifferentiation by inhibiting TGF-β-mediated ERK signaling

Epithelial-to-mesenchymal transdifferentiation (EMT) mediated by transforming growth factor-β (TGF-β) signaling leads to aggressive cancer progression. In this study, we identified zinc-α2-glycoprotein (AZGP1, ZAG) as a tumor suppressor in pancreatic ductal adenocarcinoma whose expression is lost due to histone deacetylation. In vitro, ZAG silencing strikingly increased invasiveness of pancreatic cancer cells accompanied by the induction of a mesenchymal phenotype. Expression analysis of a set of EMT markers showed an increase in the expression of mesenchymal markers (vimentin (VIM) and integrin-α5) and a concomitant reduction in the expression of epithelial markers (cadherin 1 (CDH1), desmoplakin and keratin-19). Blockade of endogenous TGF-β signaling inhibited these morphological changes and the downregulation of CDH1, as elicited by ZAG silencing. In a ZAG-negative cell line, human recombinant ZAG (rZAG) specifically inhibited exogenous TGF-β-mediated tumor cell invasion and VIM expression. Furthermore, rZAG blocked TGF-β-mediated ERK2 phosphorylation. PCR array analysis revealed that ZAG-induced epithelial transdifferentiation was accompanied by a series of concerted cellular events including a shift in the energy metabolism and prosurvival signals. Thus, epigenetically regulated ZAG is a novel tumor suppressor essential for maintaining an epithelial phenotype.