NMDA receptors are expressed in human ovarian cancer tissues and human ovarian cancer cell lines

Adapting the endoplasmic reticulum proteostasis rescues epilepsy-associated NMDA receptor variants

The GRIN genes encoding N-methyl-D-aspartate receptor (NMDAR) subunits are remarkably intolerant to variation. Many pathogenic NMDAR variants result in their protein misfolding, inefficient assembly, reduced surface expression, and impaired function on neuronal membrane, causing neurological disorders including epilepsy and intellectual disability. Here, we investigated the proteostasis maintenance of NMDARs containing epilepsy-associated variations in the GluN2A subunit, including M705V and A727T. In the transfected HEK293T cells, we showed that the two variants were targeted to the proteasome for degradation and had reduced functional surface expression. We demonstrated that the application of BIX, a known small molecule activator of an HSP70 family chaperone BiP (binding immunoglobulin protein) in the endoplasmic reticulum (ER), dose-dependently enhanced the functional surface expression of the M705V and A727T variants in HEK293T cells. Moreover, BIX (10 μM) increased the surface protein levels of the M705V variant in human iPSC-derived neurons. We revealed that BIX promoted folding, inhibited degradation, and enhanced anterograde trafficking of the M705V variant by modest activation of the IRE1 pathway of the unfolded protein response. Our results suggest that adapting the ER proteostasis network restores the folding, trafficking, and function of pathogenic NMDAR variants, representing a potential treatment for neurological disorders resulting from NMDAR dysfunction.

Morphine stimulates cervical cancer cells and alleviates cytotoxicity of chemotherapeutic drugs via opioid receptor-dependent and -independent mechanisms

Morphine is frequently applied in cancer patients for pain management. However, its effects on cancer are not well understood but observed to be specific to certain cancer types. We previously revealed the stimulatory properties of morphine in esophageal carcinoma. This work addressed the effects of morphine and its underlying mechanisms in cervical cancer. Proliferation, apoptosis, and migration assays were performed to examine the effects of morphine alone and its combinatory effects with chemotherapeutic drugs. Immunoblotting and biochemical analysis were performed to determine the underlying mechanisms of morphine's action. Morphine promoted proliferation in opioid receptor-dependent manner and stimulated migration in opioid receptor-independent manner. However, morphine did not affect cervical cancer cell survival. Morphine also interfered with all tested chemotherapeutic drugs (e.g., cisplatin, 5-FU, and paclitaxel) and alleviates their efficacy. Mechanistically, morphine-stimulated growth via activating EGFR-mediated signaling pathways and is opioid-receptor-dependent; morphine-stimulated migration via activating RhoA-mediated signaling pathways and this is opioid receptor-independent. Our work suggests a strong correlation of this opioid receptor on growth factor signaling to stimulate growth and opioid receptor-independent activation of RhoA and consequent migration. Our findings have the potential to guide the clinical use of morphine for patients with cervical cancer.

Heterogeneity and Functions of Tumor-Infiltrating Antibody Secreting Cells: Lessons from Breast, Ovarian, and Other Solid Cancers

Simple Summary

B cells are gaining increasing recognition as important contributors to the tumor microenvironment, influencing, positively or negatively, tumor growth, patient survival, and response to therapies. Antibody secreting cells (ASCs) constitute a variable fraction of tumor-infiltrating B cells in most solid tumors, and they produce tumor-specific antibodies that can drive distinct immune responses depending on their isotypes and specificities. In this review, we discuss the current knowledge of the heterogeneity of ASCs infiltrating solid tumors and how both their canonical and noncanonical functions shape antitumor immunity, with a special emphasis on breast and ovarian cancers.

Abstract

Neglected for a long time in cancer, B cells and ASCs have recently emerged as critical actors in the tumor microenvironment, with important roles in shaping the antitumor immune response. ASCs indeed exert a major influence on tumor growth, patient survival, and response to therapies. The mechanisms underlying their pro- vs. anti-tumor roles are beginning to be elucidated, revealing the contributions of their secreted antibodies as well as of their emerging noncanonical functions. Here, concentrating mostly on ovarian and breast cancers, we summarize the current knowledge on the heterogeneity of tumor-infiltrating ASCs, we discuss their possible local or systemic origin in relation to their immunoglobulin repertoire, and we review the different mechanisms by which antibody (Ab) subclasses and isoforms differentially impact tumor cells and anti-tumor immunity. We also discuss the emerging roles of cytokines and other immune modulators produced by ASCs in cancer. Finally, we propose strategies to manipulate the tumor ASC compartment to improve cancer therapies.

Paraneoplastic and Other Autoimmune Encephalitides: Antineuronal Antibodies, T Lymphocytes, and Questions of Pathogenesis

Autoimmune and paraneoplastic encephalitides represent an increasingly recognized cause of devastating human illness as well as an emerging area of neurological injury associated with immune checkpoint inhibitors. Two groups of antibodies have been detected in affected patients. Antibodies in the first group are directed against neuronal cell surface membrane proteins and are exemplified by antibodies directed against the N-methyl-D-aspartate receptor (anti-NMDAR), found in patients with autoimmune encephalitis, and antibodies directed against the leucine-rich glioma-inactivated 1 protein (anti-LGI1), associated with faciobrachial dystonic seizures and limbic encephalitis. Antibodies in this group produce non-lethal neuronal dysfunction, and their associated conditions often respond to treatment. Antibodies in the second group, as exemplified by anti-Yo antibody, found in patients with rapidly progressive cerebellar syndrome, and anti-Hu antibody, associated with encephalomyelitis, react with intracellular neuronal antigens. These antibodies are characteristically found in patients with underlying malignancy, and neurological impairment is the result of neuronal death. Within the last few years, major advances have been made in understanding the pathogenesis of neurological disorders associated with antibodies against neuronal cell surface antigens. In contrast, the events that lead to neuronal death in conditions associated with antibodies directed against intracellular antigens, such as anti-Yo and anti-Hu, remain poorly understood, and the respective roles of antibodies and T lymphocytes in causing neuronal injury have not been defined in an animal model. In this review, we discuss current knowledge of these two groups of antibodies in terms of their discovery, how they arise, the interaction of both types of antibodies with their molecular targets, and the attempts that have been made to reproduce human neuronal injury in tissue culture models and experimental animals. We then discuss the emerging area of autoimmune neuronal injury associated with immune checkpoint inhibitors and the implications of current research for the treatment of affected patients.

Unraveling Autocrine Signaling Pathways through Metabolic Fingerprinting in Serous Ovarian Cancer Cells

Focusing on defining metabolite-based inter-tumoral heterogeneity in ovarian cancer, we investigated the metabolic diversity of a panel of high-grade serous ovarian carcinoma (HGSOC) cell-lines using a metabolomics platform that interrogate 731 compounds. Metabolic fingerprinting followed by 2-dimensional and 3-dimensional principal component analysis established the heterogeneity of the HGSOC cells by clustering them into five distinct metabolic groups compared to the fallopian tube epithelial cell line control. An overall increase in the metabolites associated with aerobic glycolysis and phospholipid metabolism were observed in the majority of the cancer cells. A preponderant increase in the levels of metabolites involved in trans-sulphuration and glutathione synthesis was also observed. More significantly, subsets of HGSOC cells showed an increase in the levels of 5-Hydroxytryptamine, γ-aminobutyrate, or glutamate. Additionally, 5-hydroxytryptamin synthesis inhibitor as well as antagonists of γ-aminobutyrate and glutamate receptors prohibited the proliferation of HGSOC cells, pointing to their potential roles as oncometabolites and ligands for receptor-mediated autocrine signaling in cancer cells. Consistent with this role, 5-Hydroxytryptamine synthesis inhibitor as well as receptor antagonists of γ-aminobutyrate and Glutamate-receptors inhibited the proliferation of HGSOC cells. These antagonists also inhibited the three-dimensional spheroid growth of TYKNU cells, a representative HGSOC cell-line. These results identify 5-HT, GABA, and Glutamate as putative oncometabolites in ovarian cancer metabolic sub-type and point to them as therapeutic targets in a metabolomic fingerprinting-based therapeutic strategy.

N-acetylaspartate release by glutaminolytic ovarian cancer cells sustains protumoral macrophages

Glutaminolysis is known to correlate with ovarian cancer aggressiveness and invasion. However, how this affects the tumor microenvironment is elusive. Here, we show that ovarian cancer cells become addicted to extracellular glutamine when silenced for glutamine synthetase (GS), similar to naturally occurring GS-low, glutaminolysis-high ovarian cancer cells. Glutamine addiction elicits a crosstalk mechanism whereby cancer cells release N-acetylaspartate (NAA) which, through the inhibition of the NMDA receptor, and synergistically with IL-10, enforces GS expression in macrophages. In turn, GS-high macrophages acquire M2-like, tumorigenic features. Supporting this in␣vitro model, in silico data and the analysis of ascitic fluid isolated from ovarian cancer patients prove that an M2-like macrophage phenotype, IL-10 release, and NAA levels positively correlate with disease stage. Our study uncovers the unprecedented role of glutamine metabolism in modulating macrophage polarization in highly invasive ovarian cancer and highlights the anti-inflammatory, protumoral function of NAA.

Glutamate receptor, ionotropic, N‑methyl D‑aspartate‑associated protein 1 promotes colorectal cancer cell proliferation and metastasis, and is negatively regulated by miR‑296‑3p

N‑methyl D‑aspartate receptors (NMDARs) are closely associated with the development, growth and metastasis of cancer. Glutamate receptor, ionotropic, N‑methyl D‑aspartate‑associated protein 1 (GRINA) is a member of the of the NMDAR family, and its aberrant expression is associated with gastric cancer. However, the role of GRINA in colorectal cancer (CRC) is not completely understood. In the present study, expression profiles of GRINA in several CRC databases were obtained and further verified using clinical CRC samples. The effects of GRINA overexpression on CRC progression both in vivo and in vitro were assessed. Briefly, cell proliferation was detected using MTT assay, and cell migration and invasion ability were evaluated by wound healing and Transwell assay. In addition, the molecular mechanism underlying the upregulated expression of GRINA in CRC was investigated. The regulatory association between GRINA and miR‑296‑3p was detected by luciferase assay, reverse transcription‑quantitative PCR and western blotting. The results demonstrated that GRINA expression levels were significantly increased in tumor samples compared with those in healthy samples, and upregulated expression of GRINA was associated with a less favorable prognostic outcome in patients with CRC. GRINA overexpression significantly increased CRC cell proliferation, invasion and migration. Additionally, it was determined that GRINA was post‑transcriptionally regulated by microRNA (miR)‑296‑3p. Together, the results of the present study suggested the potential importance of the miR‑296‑3p/GRINA axis and highlighted potential novel targets for the management of CRC.

Ketamine Inhibits Ovarian Cancer Cell Growth by Regulating the lncRNA-PVT1/EZH2/p57 Axis

Ketamine is widely used for cancer pain treatment in clinic, and has been shown to inhibit various tumor cells growth. However, the effect of ketamine on ovarian cancer cells growth and the downstream molecules has not been defined. In the present study, we found that ketamine significantly inhibited the proliferation and survival of six ovarian cancer cell lines. Moreover, ketamine induced ovarian cancer cell cycle arrest, apoptosis, and inhibited colony formation capacity. Since lncRNAs have been identified as key regulators of cancer development, we performed bioinformatics analysis of a GEO dataset and found fourteen significantly altered lncRNAs in ovarian cancer patients. We then investigated the effect of ketamine on these lncRNAs, and found that ketamine regulated the expression of lncRNA PVT1. Mechanistically, ketamine regulated P300-mediated H3K27 acetylation activation in the promoter of PVT1. Our RNA immunoprecipitation experiment indicated that PVT1 bound histone methyltransferase enhancer of zeste homolog 2 (EZH2), and regulated the expression of target gene, including p57, and consequently altered ovarian cancer cell biology. Our study revealed that ketamine could be a potential therapeutic strategy for ovarian cancer patients.

Morphine Stimulates Migration and Growth and Alleviates the Effects of Chemo Drugs via AMPK-Dependent Induction of Epithelial-Mesenchymal Transition in Esophageal Carcinoma Cells

The role of morphine, an opioid analgesic drug, in cancer biology has increasingly garnered attention due to its frequent usage in postoperative period for pain management in cancer patients. In this work, we demonstrated that morphine, at clinically relevant concentrations, stimulated migration and growth, and alleviated chemo drugs' efficacy in esophageal carcinoma cells. Although morphine did not affect survival, it protected esophageal carcinoma cells from chemo drugs-induced apoptosis. Mechanistical studies showed that morphine increased RhoA but not Rac1 activity. In addition, morphine activated AMP-activated protein kinase (AMPK) pathway, induced epithelial-mesenchymal transition (EMT) via upregulating Snail and Slug levels, and increased oxidative stress in esophageal carcinoma cells. Rescue studies further demonstrated that the stimulatory effects of morphine in esophageal carcinoma cells are through activation of AMPK pathway but not RhoA or opioid receptor. In addition, morphine induced EMT in an AMPK-dependent manner whereas increased RhoA activity in an AMPK-independent manner. Our work demonstrates the protective role of morphine on esophageal carcinoma cells via AMPK activation, which may provide a new guide in clinical use of morphine for patients with esophageal carcinoma.

Phosphorylation of NMDA receptors by cyclin B/CDK1 modulates calcium dynamics and mitosis

N-methyl-D-aspartate receptors (NMDAR) are glutamate-gated calcium channels named after their artificial agonist. NMDAR are implicated in cell proliferation under normal and pathophysiological conditions. However, the role of NMDAR during mitosis has not yet been explored in individual cells. We found that neurotransmitter-evoked calcium entry via endogenous NMDAR in cortical astrocytes was transient during mitosis. The same occurred in HEK293 cells transfected with the NR1/NR2A subunits of NMDAR. This transient calcium entry during mitosis was due to phosphorylation of the first intracellular loop of NMDAR (S584 of NR1 and S580 of NR2A) by cyclin B/CDK1. Expression of phosphomimetic mutants resulted in transient calcium influx and enhanced NMDAR inactivation independent of the cell cycle phase. Phosphomimetic mutants increased entry of calcium in interphase and generated several alterations during mitosis: increased mitotic index, increased number of cells with lagging chromosomes and fragmentation of pericentriolar material. In summary, by controlling cytosolic calcium, NMDAR modulate mitosis and probably cell differentiation/proliferation. Our results suggest that phosphorylation of NMDAR by cyclin B/CDK1 during mitosis is required to preserve mitotic fidelity. Altering the modulation of the NMDAR by cyclin B/CDK1 may conduct to aneuploidy and cancer.

lncRNA-uc003opf.1 rs11752942 A>G polymorphism decreases neuroblastoma risk in Chinese children

Recent studies have revealed that long non-coding RNAs (lncRNAs) play critical roles in the tumorigenesis and proliferation of human cancer. Several polymorphisms of lncRNAs have been found to be involved in the risk of neuroblastoma (NB). However, studies on the relationship between polymorphisms in lncRNA exons and NB are infrequent. We evaluated the association between rs11752942 A > G polymorphism in lnc-RNA-uc003opf.1 exon and neuroblastoma susceptibility by performing a hospital-based study with 275 patients and 531 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) assessed by using logistic regression models were used to determine the strength of the association. We found that the rs11752942 G allele is significantly associated with decreased neuroblastoma risk (AG vs. AA: adjusted OR = 0.72, 95% CI = 0.53-0.98, P = 0.038; and AG/GG vs. AA: adjusted OR = 0.74, 95% CI = 0.55-0.99, P = 0.045) after adjusting for age and gender. This association was more prominent in females, subjects with tumor in the mediastinum or early-stage. Furthermore, the expression quantitative trait locus analysis indicated that rs11752942 G was associated with decreased expression of its neighboring gene LRFN2 mRNA. These results indicate that lncRNA-uc003opf.1 may be a novel potentially functional lncRNA that may be used as a predictive marker, for it might contribute to decreased neuroblastoma risk.

Anti-N-methyl-D-aspartate Receptor Encephalitis: Case Series of Psychiatric Presentations

Anti-NMDAR encephalitis is an autoimmune encephalitis with a typical clinical progression. Patients can often present to psychiatric outpatient departments (OPDs) mimicking psychiatric illnesses. In this case series, we have described two cases of adolescent age group that were eventually diagnosed with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. They had presented to psychiatry OPD and were admitted to the psychiatry ward. Both cases had predominantly, although varied, psychiatric symptoms with a variable course, response to treatment and prognosis. We have tried to speculate if initial presentation in anti-NMDAR encephalitis can be suggestive or can predict response to treatment and prognosis in a patient. We advocate a high degree of suspicion for psychiatrists toward patients presenting acutely in the first episode of mania or psychosis, particularly in adolescent age group.

Red and near-infrared light induces intracellular Ca2+ flux via the activation of glutamate N-methyl-D-aspartate receptors

Red and near-infrared (NIR) light effect on Ca²⁺ ions flux through the influence on N-methyl-D-aspartate receptors (NMDARs) and their functioning in HeLa cells was studied in vitro. Cells were irradiated by 650 and 808 nm laser light at different power densities and doses and the obtained effect was compared with that caused by the pharmacological agents. The laser light was found to elevate Ca²⁺ influx into cell cytoplasm in a dose-dependent manner without changes of the NMDAR functioning. Furthermore, the light of both wavelengths demonstrated the ability to elevate Ca²⁺ influx under the pharmacological blockade of NMDARs and also might partially abolish the blockade enhancing Ca²⁺ influx after selective stimulation of the receptors with NMDA. Simultaneously, the light at moderate doses demonstrated a photobiostimulating effect on cells. Based on our experiments and data reported in the literature, we suggest that the low-power visible and NIR light can instigate a cell membrane depolarization via nonthermal activation, resulting in the fast induction of Ca²⁺ influx into cells. The obtained results also demonstrate that NIR light can be used for nonthermal and nonpharmacological stimulation of NMDARs in cancer cells.

Intronic polymorphisms in genes LRFN2 (rs2494938) and DNAH11 (rs2285947) are prognostic indicators of esophageal squamous cell carcinoma

Background

Genome wide association study (GWAS) has become the major means to screen for the genetic variants associated with risk and prognosis of different diseases. A recent GWAS has discovered three novel intronic single nucleotide polymorphisms in genes LRFN2 (rs2494938), DNAH11 (rs2285947) and PLCXD2 (rs2399395) that are associated with altered risk of esophageal squamous cell carcinoma (ESCC) among Han Chinese populations. However, the prognostic significance of these variations in ESCC remains unclear.

Methods

To investigate the association of three novel single nucleotide polymorphisms (rs2494938, rs2285947, rs2399395) with the prognosis of ESCC patients, we recruited 287 ESCC patients treated with surgical resection and evaluated the potential significance of the three polymorphisms through Kaplan-Meier survival analysis, log-rank test, and Cox proportional hazards regression models.

Results

The ESCC patients carrying genotype AA at rs2494938 had worse survival and genotype GG at 2285947 had better prognosis (Log-rank P = 0.003 and Log-rank P = 0.037, respectively). In addition, rs2494938 at 6p21.1 was independently associated with overall survival of ESCC patients in recessive model [AA vs. GG/GA, HR = 3.12, 95% CI = 1.43–6.83, P = 0.004], rs2285947 at 7p15.3 was independently associated with overall survival of ESCC patients in both dominant model [AA/GA vs. GG, HR = 1.59, 95% CI = 1.02–2.49, P = 0.042] and additive model [AA vs. GA vs. GG, HR = 1.45, 95% CI = 1.05–2.01, P = 0.025].

Conclusions

This study demonstrated that the polymorphisms rs2494938 at 6p21.1 and rs2285947 at 7p15.3 may serve as independent prognostic biomarkers for ESCC, implying the potential biological role of their related genes (LRFN2 and DNAH11) in the process of ESCC development.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0796-9) contains supplementary material, which is available to authorized users.

Discovery of therapeutic agents for prostate cancer using genome-scale metabolic modeling and drug repositioning

BACKGROUND

Genome-scale metabolic models (GEMs) offer insights into cancer metabolism and have been used to identify potential biomarkers and drug targets. Drug repositioning is a time- and cost-effective method of drug discovery that can be applied together with GEMs for effective cancer treatment.

METHODS

In this study, we reconstruct a prostate cancer (PRAD)-specific GEM for exploring prostate cancer metabolism and also repurposing new therapeutic agents that can be used in development of effective cancer treatment. We integrate global gene expression profiling of cell lines with >1000 different drugs through the use of prostate cancer GEM and predict possible drug-gene interactions.

FINDINGS

We identify the key reactions with altered fluxes based on the gene expression changes and predict the potential drug effect in prostate cancer treatment. We find that sulfamethoxypyridazine, azlocillin, hydroflumethiazide, and ifenprodil can be repurposed for the treatment of prostate cancer based on an in silico cell viability assay. Finally, we validate the effect of ifenprodil using an in vitro cell assay and show its inhibitory effect on a prostate cancer cell line.

INTERPRETATION

Our approach demonstate how GEMs can be used to predict therapeutic agents for cancer treatment based on drug repositioning. Besides, it paved a way and shed a light on the applicability of computational models to real-world biomedical or pharmaceutical problems.

Immunopathological characterization of ovarian teratomas associated with anti-N-methyl-D-aspartate receptor encephalitis

Encephalitis with anti-NMDAR antibodies (NMDAR-E) is a severe autoimmune neurological disorder, defined by a clinical presentation of encephalitis and the presence of IgG targeting the GluN1 subunit of NMDA receptors in the CSF. An underlying ovarian teratoma is commonly associated with this autoimmune disease suggesting a role of the tumor in immunopathogenesis. In this study, we characterized the salient histopathological features of 27 ovarian teratomas associated with NMDAR-E (3 immature and 24 mature teratomas) and 40 controls without associated encephalitis. All but one NMDAR-E-associated teratomas contained a nervous tissue component, while less than 40% of control teratomas did (p < 0.001). GluN1 expression by teratomatous nervous tissue seemed to be more often glial in NMDAR-E teratomas than in control teratomas (73% vs. 29%, p < 0.05). Strikingly, 3 out of 24 NMDAR-E-associated mature teratomas contained neuroglial tissue exhibiting histopathological features of central nervous system neuroglial tumor, while such glioma-like features are exceptionally described in the literature on ovarian teratomas. Moreover, NMDAR-E associated teratomas differed from sporadic ovarian teratomas by consistent and prominent infiltration of the nervous tissue component by immune cells, comprised of T- and B-cells and mature dendritic cells organized in tertiary lymphoid structures, with IgG and IgA deposits and plasma cells in close contact to the neuroglial tissue.

These data demonstrate an association between massive infiltration of NMDAR-E-associated teratomas by immune cells and particular glial features of its neuroglial component, suggesting that this glial tissue might be involved in triggering or sustaining the anti-tumor response associated with the auto-immune neurological disease.

Small-cell lung cancer growth inhibition: synergism between NMDA receptor blockade and chemotherapy

Background

Small-cell lung cancer (SCLC) has a poor prognosis since there is currently no effective therapy for commonly recurring disease. In our previous study, both primary and recurrent human tumors have been shown to express functional N-methyl-D-aspartate (NMDA) receptors, and blockade of these receptors with GluN1 and GluN2B antagonists decreased tumor cell viability in vitro, and growth of tumor xenografts in nu/nu mice.

Materials and methods

In this study, we examine the influence of the GluN2B antagonist ifenprodil and the channel-blocker antagonist memantine, on cell viability and growth of tumor xenografts of recurrent SCLC (rSCLC) in mice.

Results

Both antagonists significantly reduced cell viability and levels of components of the ERK1/2 pathway, increased apoptosis, and at very safe levels significantly reduced the growth of tumors in mice. Each antagonist and topotecan had additive effects to reduce cell viability with significant synergy demonstrated for the case of memantine. More significantly, combination treatments of xenografts in mice with ifenprodil and the chemotherapeutic agent topotecan produced clear additive effects that completely stopped tumor growth. Moreover, the ifenprodil and topotecan combination showed excellent supra-addition or synergy of inhibition for tumors ≤300 mm in size (P=4.7E−4). Combination treatment of memantine with topotecan also showed clear addition but, unlike ifenprodil, no synergy for the doses chosen.

Conclusion

Since topotecan is a drug of choice for treatment of rSCLC, our findings suggest that combining this agent with NMDA receptor blockade using the GluN2B antagonist, ifenprodil, will significantly improve patient outcomes.

Transmembrane protein GRINA modulates aerobic glycolysis and promotes tumor progression in gastric cancer

BACKGROUND

Recent observations indicate a decreased cancer risk in patients with Alzheimer's disease (AD). AD is a severe neurodegenerative disorder characterized by progressive cognitive decline. The 8q24 region has been shown to be involved in AD aetiology. We aimed to identify and explore the potential oncogenes or antioncogenes on chromosome 8q24.

METHODS

We compared expression of genes on Chromosome 8q24 in 32 pairs of samples from The Cancer Genome Atlas (TCGA) database. We conducted bioinformatics analysis of the commonly used gastric cancer databases and performed clinical verification of gastric cancer samples, combined with assessment of biological function both in vitro and in vivo to determine the relationship between upregulated expression of GRINA and gastric cancer progression. We also explored the molecular mechanism of GRINA upregulation and its function in gastric cancer development and progression.

RESULTS

The expression of GRINA in cancer tissues was significantly higher than that in normal tissues. GRINA indicated poor prognosis in gastric cancer. GRINA promoted the proliferation, migration and invasion capacity of gastric cancer cells. GRINA was transcriptionally mediated by c-Myc and promotes cell cycle transition. GRINA knockdown decreased PI3K/Akt/mTOR signaling and glycolytic metabolism in gastric cancer cells. The apoptosis rate was significantly increased in gastric cancer cell lines after knockdown of GRINA. The expression of pro-apoptotic protein Bax was significantly upregulated, whereas the anti-apoptotic protein Bcl-2 was significantly downregulated in GRINA silenced cells.

CONCLUSIONS

Human gastric cancers have increased levels of GRINA, which promotes growth of gastric cancer and inhibits tumor cells apoptosis.

NMDA receptors are important regulators of pancreatic cancer and are potential targets for treatment

Pancreatic cancer, particularly adenocarcinoma of the pancreas, is a common disease with a poor prognosis. In this study, the importance of N-methyl-D-aspartate (NMDA) receptors for the growth and survival of pancreatic cancer was investigated. Immunohistochemistry performed with antibodies against GluN1 and GluN2B revealed that all invasive adenocarcinoma and neuroendocrine pancreatic tumors likely express these two NMDA receptor proteins. These proteins were found to be membrane components of pancreatic cancer cell lines, and both channel-blocker antagonist and GluN2B antagonist significantly reduced cell viability in vitro. Both types of antagonists caused an internalization of the receptors. Dizocilpine maleate (MK-801) and ifenprodil hemitartrate both significantly inhibited the growth of pancreatic tumor xenografts in nu/nu mice. These findings predict that, as for other solid tumors investigated by us, pancreatic cancer could be successfully treated, alone or in combination, with NMDA receptor antagonists or other receptor-inhibiting blocking agents.