Clinical significance of glutamate metabotropic receptors in renal cell carcinoma risk and survival

Expression of mGluR5 in Pediatric Hodgkin and Non-Hodgkin lymphoma-A Comparative Analysis of Immunohistochemical and Clinical Findings Regarding the Association between Tumor and Paraneoplastic Neurological Disease

Autoantibodies targeting the neuronal antigen metabotropic glutamate receptor 5 (mGluR5) have been identified in patients with Ophelia syndrome, which describes a co-occurrence of paraneoplastic limbic encephalitis and Hodgkin lymphoma (HL). Little data exist regarding frequency and function of mGluR5 in HL and its potential role in causing seropositive paraneoplastic disease. We studied a representative cohort of pediatric HL and NHL patients (n = 57) using immunohistochemistry and fluorescence staining to investigate mGluR5 expression. All lymphoma tissues displayed positive mGluR5 staining, with focus on Hodgkin-Reed-Sternberg (H-RS) cells. We did not detect any mGluR5 staining in tumor-free lymph nodes, which is consistent with the absence of GRM5 transcripts in RNA-sequencing data from non-malignant B and T cells. The frequent presence in pediatric lymphoma falls in line with reports of mGluR5 expression and associated tumor progression in other malignancies. We tested for correlation with clinical features, focusing on disease progression and neurological symptoms. Low mGluR5 expression in H-RS cells correlated with young patient age (<15 years) and positive histology for EBV infection. Paraneoplastic or neurological symptoms were found exclusively in HL patients. While an impact of mGluR5 on HL severity remains possible, a prognostic value of mGluR5 expression levels requires further investigation.

Low expression of GRM4 is associated with poor prognosis and tumor immune infiltration in glioma

INTRODUCTION

The metabotropic glutamate receptor 4 (mGlu4, GRM4) exhibits significant expression within the central nervous system (CNS) and has been implicated to be correlated with a poor prognosis.

OBJECTIVE

This study was aimed to elucidate the relationship between the expression profile of GRM4 and the prognosis of glioma patients.

METHODS

RNA-sequencing datasets from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and China Glioma Genome Atlas (CGGA) repositories were used to evaluate the potential relationship. The value of clinical prognostic about GRM4 was assessed using clinical survival data from CGGA and TCGA. The GEPIA database was used to select genes like GRM4. PPI network was constructed by the database of (STRING), GO and KEGG analyses were performed. TargetScan, TarBase, miRDB, and starBase were used to explore miRNAs that could regulate GRM4 expression. EWAS Data Hub, MethSurv, and MEXPRESS were used for the analysis and relationship between DNA methylation and GRM4 expression and prognosis in glioma. TIMER2.0 and CAMOIP databases were used to assess the association between immune cell infiltration and GRM4. Human GBM cell lines were used to validate the function of GRM4.

RESULTS

Our study shows that GRM4 is under expressed among gliomas and accompanied by poorer OS. Multivariate analysis showed that low mRNA expression of GRM4 was an independent factor of prognostic for shorter OS in all glioma patients. MiR-1262 affects the malignant phenotype of gliomas through GRM4. Methylation of DNA plays an important role in the instruction of GRM4 expression, the methylation level of GRM4 in glioma tissue is higher in comparison to normal tissue, and the higher methylation level was accompanied with the worse prognosis. Further analysis showed that GRM4 mRNA expression in GBM linked negatively with common lymphoid progenitor, Macrophage M1, Macrophage, and T cell CD4+ Th2, but not with the tumor purity. Overexpression of GRM4 prevents the migration of human GBM cell lines in vitro.

CONCLUSION

GRM4 may have a substantial impact on the infiltration of immune cells and serve as a valuable prognostic biomarker in gliomas.

CYBA as a Potential Biomarker for Renal Cell Carcinoma: Evidence from an Integrated Genetic Analysis

BACKGROUND/AIM

Oxidative stress plays an important role in various pathogenic processes, and disruption in the coordinated production of NADPH oxidase (NOX)-derived reactive oxygen species has been associated with carcinogenesis. However, little is known about whether genetic variants in NOX can contribute to the development of renal cell carcinoma (RCC).

PATIENTS AND METHODS

This study aimed to bridge this knowledge gap by analysing the association of 10 single-nucleotide polymorphisms in the phagocyte NOX genes, CYBA and CYBB, with RCC risk and tumour characteristics in 630 RCC patients and controls. Differential gene expression and patient prognosis analyses were performed using gene expression data obtained from public databases.

RESULTS

Multivariate analysis and multiple testing corrections revealed the A allele of rs7195830 in CYBA to be a significant risk allele for RCC, compared to the G allele [odds ratio (OR)=1.70, 95% confidence interval (CI)=1.27-2.26, p<0.001]. A pooled analysis of 17 renal cancer gene expression datasets revealed a higher CYBA expression in RCC than in normal tissues. Moreover, high CYBA expression was associated with advanced tumour characteristics and worse patient prognosis.

CONCLUSION

CYBA might play an oncogenic role in RCC and serve as a predictive indicator of patient prognosis.

Silencing of Long Noncoding RNA GAS5 Blocks Experimental Cerebral Ischemia-Reperfusion Injury by Restraining AQP4 Expression via the miR-1192/STAT5A Axis

The long noncoding RNA (lncRNA) GAS5 has been shown to affect disease development in stroke. This study aimed to elucidate the regulatory mechanism of the lncRNA GAS5 on STAT5A in cerebral ischemia/reperfusion (I/R) injury. First, GAS5 and STAT5A levels in the blood of patients with stroke were determined. Then, a middle cerebral artery occlusion and reperfusion rat model was established in which short hairpin RNAs targeting GAS5 or STAT5A were intracranially injected, followed by the assessment of neurological function, cerebral injury and water content, and inflammation. Primary rat astrocytes were induced with oxygen-glucose deprivation/reoxygenation (OGD/R), and cell proliferation, apoptosis, and inflammation were evaluated. Moreover, the interplay between GAS5, miR-1192, and STAT5A and the binding of STAT5A to the AQP4 promoter were identified. GAS5 and STAT5A were strongly expressed in stroke patients, and inhibition of GAS5 or STAT5A in model rats improved neurological function, reduced infarction and neuronal apoptosis, and diminished cerebral water content and astrocyte activation. Furthermore, GAS5 or STAT5A downregulation restored proliferation and restrained apoptosis and inflammation in OGD/R-induced astrocytes. Mechanistically, GAS5 targeted miR-1192, which negatively regulated STAT5A. Astrocytes showed perturbed proliferation and strengthened apoptosis and inflammation when miR-1192 was inhibited despite the silencing of GAS5, while these unfavorable effects were abolished by STAT5A silencing. STAT5A binds to the AQP4 promoter and regulates its expression. Silencing of GAS5 and overexpresion of AQP4 led to lower cell viability and higher apoptosis and inflammation than GAS5 silencing alone. Overall, GAS5 silencing inhibited AQP4 through the miR-1192/STAT5A axis, thus alleviating cerebral I/R injury.

Genetic Analysis Implicates Dysregulation of SHANK2 in Renal Cell Carcinoma Progression

SH3 and multiple ankyrin repeat domains (SHANK) is a family of scaffold proteins that were first identified to be involved in balancing synaptic transmission via regulation of intracellular signalling crosstalk and have been linked to various cancers. However, the role of the SHANK genes in renal cell carcinoma (RCC) remains to be elucidated. In this study, we aimed to evaluate whether genetic variants in SHANK family genes affect the risk of RCC and survival of patients. A genetic association study was conducted using logistic regression and Cox regression analyses, followed by the correction for a false discovery rate (FDR), in 630 patients with RCC and controls. A pooled analysis was further performed to summarise the clinical relevance of SHANK gene expression in RCC. After adjustment for known risk factors and the FDR, the SHANK2 rs10792565 T allele was found to be associated with an increased risk of RCC (adjusted odds ratio = 1.79, 95% confidence interval = 1.32-2.44, p = 1.96 × 10^-4, q = 0.030), whereas no significant association was found with RCC survival. A pooled analysis of 19 independent studies, comprising 1509 RCC and 414 adjacent normal tissues, showed that the expression of SHANK2 was significantly lower in RCC than in normal tissues (p < 0.001). Furthermore, low expression of SHANK2 was correlated with an advanced stage and poor prognosis for patients with clear cell and papillary RCC. This study suggests that SHANK2 rs10792565 is associated with an increased risk of RCC and that SHANK2 may play a role in RCC progression.

Implications of a Neuronal Receptor Family, Metabotropic Glutamate Receptors, in Cancer Development and Progression

Cancer is the second leading cause of death, and incidences are increasing globally. Simply defined, cancer is the uncontrolled proliferation of a cell, and depending on the tissue of origin, the cancer etiology, biology, progression, prognosis, and treatment will differ. Carcinogenesis and its progression are associated with genetic factors that can either be inherited and/or acquired and are classified as an oncogene or tumor suppressor. Many of these genetic factors converge on common signaling pathway(s), such as the MAPK and PI3K/AKT pathways. In this review, we will focus on the metabotropic glutamate receptor (mGluR) family, an upstream protein that transmits extracellular signals into the cell and has been shown to regulate many aspects of tumor development and progression. We explore the involvement of members of this receptor family in various cancers that include breast cancer, colorectal cancer, glioma, kidney cancer, melanoma, oral cancer, osteosarcoma, pancreatic cancer, prostate cancer, and T-cell cancers. Intriguingly, depending on the member, mGluRs can either be classified as oncogenes or tumor suppressors, although in general most act as an oncogene. The extensive work done to elucidate the role of mGluRs in various cancers suggests that it might be a viable strategy to therapeutically target glutamatergic signaling.

Glutamatergic Signaling a Therapeutic Vulnerability in Melanoma

Like other cancers, melanomas are associated with the hyperactivation of two major cell signaling cascades, the MAPK and PI3K/AKT pathways. Both pathways are activated by numerous genes implicated in the development and progression of melanomas such as mutated BRAF, RAS, and NF1. Our lab was the first to identify yet another driver of melanoma, Metabotropic Glutamate Receptor 1 (protein: mGluR1, mouse gene: Grm1, human gene: GRM1), upstream of the MAPK and PI3K/AKT pathways. Binding of glutamate, the natural ligand of mGluR1, activates MAPK and PI3K/AKT pathways and sets in motion the deregulated cellular responses in cell growth, cell survival, and cell metastasis. In this review, we will assess the proposed modes of action that mediate the oncogenic properties of mGluR1 in melanoma and possible application of anti-glutamatergic signaling modulator(s) as therapeutic strategy for the treatment of melanomas.

Genetic Analysis Identifies the Role of HLF in Renal Cell Carcinoma

BACKGROUND/AIM

Circadian rhythm is an internal clock that regulates the cycles of many biological functions. Epidemiological studies have linked aberrant circadian rhythm to an increased susceptibility to cancer and poor patient prognosis. However, there remains a gap in our understanding of genetic variants related to the circadian pathway in renal cell carcinoma (RCC) progression.

PATIENTS AND METHODS

We examined the associations of 150 single nucleotide polymorphisms (SNPs) in 12 core circadian pathway genes with RCC risk and survival in 630 patients with RCC and controls.

RESULTS

After adjusting for multiple comparisons and performing multivariate analyses, we found that the HLF rs6504958 polymorphism was significantly associated with RCC risk (q<0.05), whereas, no SNP association was significant for survival. Furthermore, the rs6504958 G allele was associated with reduced expression of HLF; consequently, a lower HLF expression was correlated with more advanced RCC. Moreover, a meta-analysis of six kidney cancer gene expression datasets demonstrated that an elevated HLF expression was associated with a favorable prognosis in patients with RCC (hazard ratio=0.70, 95% confidence interval=0.65-0.76, p<0.001).

CONCLUSION

These findings implicate the potential protective role of HLF in the progression of RCC.

Genetic variants in MAPK10 modify renal cell carcinoma susceptibility and clinical outcomes

AIMS

The mitogen-activated protein kinase (MAPK) cascades integrate various upstream signals to regulate many cellular functions, including proliferation, differentiation, and survival. Dysregulation of these pathways has been implicated in the occurrence and progression of a variety of cancers.

MAIN METHODS

This study aimed to assess the association of 192 single nucleotide polymorphisms in 22 MAPK cascade genes with renal cell carcinoma (RCC) risk and survival in 312 patients and 318 controls.

KEY FINDINGS

After multiple testing correction and multivariate analysis, the minor T allele of MAPK10 rs12648265 remained associated with a lower risk of RCC (adjusted odds ratio 0.64, 95% confidence interval 0.50-0.82, P = 0.000426) and metastasis (adjusted hazard ratio 0.50, 95% confidence interval 0.30-0.82, P = 0.006). Presence of the rs12648265 T allele demonstrated a trend towards being associated with increased MAPK10 expression, and meta-analysis of four RCC datasets indicated that high MAPK10 expression is associated with a favourable prognosis. Furthermore, activation of MAPK10 by the potent agonist anisomycin inhibited RCC cell growth in vitro, suggesting an involvement of MAPK10 in RCC progression.

SIGNIFICANCE

In conclusion, MAPK10 may be a meaningful biomarker and a potential therapeutic target in RCC.

Identification of key modules and genes associated with breast cancer prognosis using WGCNA and ceRNA network analysis

Breast cancer is one of the leading causes of cancer-associated mortality in women worldwide and has become a major public health problem. Although the definitive cause of breast cancer is not known, many genes sensitive to breast cancer have been detected using advanced technologies. Our study identified 3301 differentially expressed lncRNAs and mRNAs between tumor and normal samples from The Cancer Genome Atlas database. Based on the gene expression analysis and clinical traits as well as weighted gene co-expression network analysis, the co-expression Brown module was found to be key for breast cancer prognosis. A total of 453 genes in the Brown module were used for functional enrichment, protein-protein interaction analysis, lncRNA-miRNA-mRNA ceRNA network, and lncRNA-RNA binding protein-mRNA network construction. GRM4, SSTR2, PARD6B, PRR15, COX6C, and lncRNA DSCAM-AS1 were the hub genes according to protein-protein interaction, lncRNA-miRNA-mRNA and lncRNA-RNA binding protein-mRNA network. Their high expression was found to be correlated with breast cancer development, according to multiple databases. In conclusion, this study provides a framework of the co-expression gene modules of breast cancer and identifies several important biomarkers in breast cancer development and prognosis.

Glutamate in cancers: from metabolism to signaling

Glutamine and glutamate are major bioenergy substrates for normal and cancer cell growth. Cancer cells need more biofuel than normal tissues for energy supply, anti-oxidation activity and biomass production. Genes related to metabolic chains in many cancers are somehow mutated, which makes cancer cells more glutamate dependent. Meanwhile, glutamate is an excitatory neurotransmitter for conducting signals through binding with different types of receptors in central neuron system. Interestingly, increasing evidences have shown involvement of glutamate signaling, guided through their receptors, in human malignancy. Dysregulation of glutamate transporters, such as excitatory amino acid transporter and cystine/glutamate antiporter system, also generates excessive extracellular glutamate, which in turn, activates glutamate receptors on cancer cells and results in malignant growth. These features make glutamate an attractive target for anti-cancer drug development with some glutamate targeted but blood brain barrier impermeable anti-psychosis drugs under consideration. We discussed the relevant progressions and drawbacks in this field herein.

Clinical significance of glutamate metabotropic receptors in renal cell carcinoma risk and survival

Accumulating evidence suggests the roles of glutamate metabotropic receptors (GRMs) in cancer, in addition to synaptic signalling. The present study assessed the associations of genetic variants in eight GRM genes with regard to risk and overall survival (OS) in 780 renal cell carcinoma (RCC) patients and controls. After adjustment for known risk factors, GRM5 rs7102764 T was associated with an increased risk of RCC (P = 0.006). Additional analysis has provided evidence that rs7102764 T was correlated with a higher expression of GRM5, which is consistently found to be upregulated in tumours, compared to normal tissues. Furthermore, the GRM3 rs701332 C, GRM4 rs2499707 T, and GRM4 rs4713742 T alleles were significantly associated with a poorer OS (P ≤ 0.030). The three loci were also observed to have strong cumulative effects on OS. Additional analysis has revealed a significant genotype‐expression correlation of rs2499707 T with increased GRM4 expression, which in turn leads to poorer OS in patients with RCC. GRMs might be involved in RCC development and progression, and genetic variants in GRMs might be promising biomarkers.