Activation of JAK/STAT signal pathway predicts poor prognosis of patients with gliomas

Dual targeting of histone deacetylases and MYC as potential treatment strategy for H3-K27M pediatric gliomas

Diffuse midline gliomas (DMGs) are aggressive and fatal pediatric tumors of the central nervous system that are highly resistant to treatments. Lysine to methionine substitution of residue 27 on histone H3 (H3-K27M) is a driver mutation in DMGs, reshaping the epigenetic landscape of these cells to promote tumorigenesis. H3-K27M gliomas are characterized by deregulation of histone acetylation and methylation pathways, as well as the oncogenic MYC pathway. In search of effective treatment, we examined the therapeutic potential of dual targeting of histone deacetylases (HDACs) and MYC in these tumors. Treatment of H3-K27M patient-derived cells with Sulfopin, an inhibitor shown to block MYC-driven tumors in vivo, in combination with the HDAC inhibitor Vorinostat, resulted in substantial decrease in cell viability. Moreover, transcriptome and epigenome profiling revealed synergistic effect of this drug combination in downregulation of prominent oncogenic pathways such as mTOR. Finally, in vivo studies of patient-derived orthotopic xenograft models showed significant tumor growth reduction in mice treated with the drug combination. These results highlight the combined treatment with PIN1 and HDAC inhibitors as a promising therapeutic approach for these aggressive tumors.

Reparative effects of Schizophyllum commune oat bran fermentation broth on UVB-induced skin inflammation via the JAK/STAT pathway

Human immortal keratinocyte cells (HaCaT) are induced with UVB to establish an injury model. This model is utilized to investigate whether oat bran fermentation broth (OBF) has a reparative effect on skin inflammation and damage to the skin barrier caused by UVB irradiation. The results show that compared with unfermented oat bran (OB), OBF exhibits higher structural homogeneity, increased molecular weight size, active substances content, and in vitro antioxidant activity. OBF has a scavenging effect on excess reactive oxygen species (ROS) and increases the intracellular levels of antioxidant enzymes. It was found that OBF has a stronger inhibitory effect on the release of inflammatory factors than OB. It increases the synthesis of AQP3 and FLG proteins while decreasing the secretion of KLK-7. OBF can inhibit the transcription level of inflammatory factors by suppressing the JAK/STAT signaling pathway. Safety experiments demonstrate that OBF has a high safety profile.

Interplay between signal transducers and activators of transcription (STAT) proteins and cancer: involvement, therapeutic and prognostic perspective

Signal transducers and activators of transcription or STAT are proteins that consist of various transcription factors that are responsible for activating genes regarding cell proliferation, differentiation, and apoptosis. They commonly activate several cytokine, growth, or hormone factors via the JAK-STAT signaling pathway by tyrosine phosphorylation which are responsible for giving rise to numerous immune responses. Mutations within the Janus-Kinases (JAKs) or the STATs can set off the commencement of various malfunctions of the immune system of the body; carcinogenesis being an inevitable outcome. STATs are known to act as both oncogenes and tumor suppressor genes which makes it a hot topic of investigation. Various STATs related mechanisms are currently being investigated to analyze its potential of serving as a therapeutic base for numerous immune diseases and cancer; a deeper understanding of the molecular mechanisms involved in the signaling pathways can contribute to the same. This review will throw light upon each STAT member in causing cancer malignancies by affecting subsequent signaling pathways and its genetic and epigenetic associations as well as various inhibitors that could be used to target these pathways thereby devising new treatment options. The review will also focus upon the therapeutic advances made in cancers that most commonly affect people and discuss how STAT genes are identified as prognostic markers.

JAK3 Inhibition Regulates Stemness and Thereby Controls Glioblastoma Pathogenesis

Glioblastoma multiforme (GBM) is the most deadly brain tumor, effective treatment options for which still remain elusive. The current treatment procedure of maximal resection followed by chemotherapy has proved to be grossly insufficient to prevent disease progression and death. Despite best efforts, the maximum survival post-diagnosis is a mere 1.5 years. Therefore, there is a huge unmet clinical need to find effective therapeutic procedures to prevent the pathogenesis and relapse of GBM. Small-molecule inhibitors of signaling pathways are an attractive option to prevent various types of tumors. However, no effective small-molecule inhibitors have been successful against GBM in clinical trials. Various signaling pathways are altered and an array of signaling molecules, transcription factors (TFs), and epigenetic modifying factors have been implicated in the pathogenesis of GBM. JAK-STAT pathway alteration is an important contributor to GBM pathogenesis and relapse. Many small-molecule inhibitors of JAKs, or STAT TFs, especially JAK2 and STAT3, have been assessed for their anti-tumor activity in GBM. However, no definitive success so far has been achieved. Herein, by using two small-molecule inhibitors of JAK3, we show that they are quite effective in inhibiting GBM cell proliferation and neurosphere formation, downregulating their stemness character, and inducing differentiation into neuronal origin cells. The effect of a single treatment with the drugs, both in a serum-containing differentiation medium and in a proliferation medium containing EGF and FGF, was really strong in limiting GBM cell growth, suggesting a potential therapeutic application for these JAK inhibitors in GBM therapy.

The Spectrum of Molecular Pathways in Gliomas-An Up-to-Date Review

During the last 20 years, molecular alterations have gained increasing significance in the diagnosis and biological assessment of tumors. Gliomas represent the largest group of tumors of the central nervous system, and the main aim of this review is to present the current knowledge on molecular pathways and their alterations in gliomas. A wide range of new insights has been gained, including evidence for the involvement of the WNT pathway or the hippo pathway in the pathobiology of gliomas, indicating a broad involvement of different pathways formerly not considered to play a central role in gliomas. Even new aspects of angiogenic, apoptotic, and metabolic pathways are presented, as well as the rapidly growing field of epigenetic processes, including non-coding RNAs. The two major conclusions drawn from the present review are the distinct interconnectivity of the whole spectrum of molecular pathways and the prominent role of non-coding RNAs, especially circular RNAs, in the regulation of specific targets. All these new insights are discussed, even considering the topic of the resistance to therapy of gliomas, along with aspects that are still incompletely understood, like the role of hydroxymethylation, or even ferroptosis, in the pathobiology of gliomas.

Comprehensive analysis of the prognostic and immunological signature of eight Tripartitemotif (TRIM) family molecules in human gliomas

BACKGROUND

TRIM family molecules have been identified as being involved in the tumor progression of various cancer types. Increasingly, experimental evidence indicates that some of TRIM family molecules are implicated in glioma tumorigenesis. However, the diverse genomic changes, prognostic values and immunological landscapes of TRIM family of molecules have yet to be fully determined in glioma.

METHODS

In our study, employing the comprehensive bioinformatics tools, we evaluated the unique functions of 8 TRIM members including TRIM5/17/21/22/24/28/34/47 in gliomas.

RESULTS

The expression levels of 7 TRIM members (TRIM5/21/22/24/28/34/47) were higher in glioma as well as its diverse cancer subtypes than in normal tissues, whereas the expression level of TRIM17 was the opposite, lower in the former than in the latter. In addition, survival analysis revealed that the high expression profiles of TRIM5/21/22/24/28/34/47 were associated with poor overall survival (OS), disease-specific survival (DSS) and progress-free interval (PFI) in glioma patients, whereas TRIM17 displayed adverse outcomes. Moreover, the 8 TRIM molecules expression as well as methylation profiles remarkably correlated with different WHO grades. And genetic alterations, including mutations and copy number alterations (CNAs), in the TRIM family were correlated with longer OS, DSS and progress-free survival (PFS) in glioma patients. Furthermore, through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis results of these 8 molecules and their related genes, we found that these molecules may change the immune infiltration of the tumor microenvironment and regulate the expression of immune checkpoint molecules (ICMs), affecting the occurrence and development of gliomas. The correlation analyses between the 8 TRIM molecules and TMB (tumor mutational burden)/MSI (microsatellite instability)/ICMs discovered that as the expression level of TRIM5/21/22/24/28/34/47 increased, the TMB score also increased significantly, while TRIM17 showed an opposite outcome. Further, a 6-gene signature (TRIM 5/17/21/28/34/47) for predicting overall survival (OS) in gliomas was built by using the least absolute shrinkage and selection operator (LASSO) regression, and the survival and time-dependent ROC analyses all were found to perform well in testing and validation cohorts. Results of multivariate COX regression analysis showed that TRIM5/28 are both expected to become independent risk predictors to guide clinical treatment.

CONCLUSION

In general, the results indicate that TRIM5/17/21/22/24/28/34/47 might exert a crucial influence on gliomas tumorigenesis and might be putative prognostic markers and therapeutic targets for glioma patients.

Elevated LILRB1 expression predicts poor prognosis and is associated with tumor immune infiltration in patients with glioma

BACKGROUND

Leukocyte immunoglobulin-like receptor subfamily B1 (LILRB1) is regarded as an inhibitory molecule. However, the importance of LILRB1 expression in glioma has not yet been determined. This investigation examined the immunological signature, clinicopathological importance and prognostic value of LILRB1 expression in glioma.

METHODS

We used data from the UCSC XENA database, the Cancer Genome Atlas (TCGA) database, the Chinese Glioma Genome Atlas (CGGA) database, the STRING database, the MEXPRESS database and our clinical glioma samples to perform bioinformatic analysis and used vitro experiments to examine the predictive value and potential biological roles of LILRB1 in glioma.

RESULTS

Higher LILRB1 expression was considerably present in the higher WHO grade glioma group and was linked to a poorer prognosis in patients with glioma. Gene set enrichment analysis (GSEA) revealed that LILRB1 was positively correlated with the JAK/STAT signaling pathway. LILRB1 combined with tumor mutational burden (TMB) and microsatellite instability (MSI) may be a promising indicator for the effectiveness of immunotherapy in patients with glioma. Increased LILRB1 expression was positively linked with the hypomethylation, M2 macrophage infiltration, immune checkpoints (ICPs) and M2 macrophage makers. Univariate and multivariate Cox regression analyses determined that increased LILRB1 expression was a standalone causal factor for glioma. Vitro experiments determined that LILRB1 positively enhanced the proliferation, migration and invasion in glioma cells. MRI images demonstrated that higher LILRB1 expression was related with larger tumor volume in patients with glioma.

CONCLUSION

Dysregulation of LILRB1 in glioma is correlated with immune infiltration and is a standalone causal factor for glioma.

Regulation of Cell Plasticity by Bromodomain and Extraterminal Domain (BET) Proteins: A New Perspective in Glioblastoma Therapy

BET proteins are a family of multifunctional epigenetic readers, mainly involved in transcriptional regulation through chromatin modelling. Transcriptome handling ability of BET proteins suggests a key role in the modulation of cell plasticity, both in fate decision and in lineage commitment during embryonic development and in pathogenic conditions, including cancerogenesis. Glioblastoma is the most aggressive form of glioma, characterized by a very poor prognosis despite the application of a multimodal therapy. Recently, new insights are emerging about the glioblastoma cellular origin, leading to the hypothesis that several putative mechanisms occur during gliomagenesis. Interestingly, epigenome dysregulation associated with loss of cellular identity and functions are emerging as crucial features of glioblastoma pathogenesis. Therefore, the emerging roles of BET protein in glioblastoma onco-biology and the compelling demand for more effective therapeutic strategies suggest that BET family members could be promising targets for translational breakthroughs in glioblastoma treatment. Primarily, “Reprogramming Therapy”, which is aimed at reverting the malignant phenotype, is now considered a promising strategy for GBM therapy.

Biological implications and clinical potential of invasion and migration related miRNAs in glioma

Gliomas are the most common primary malignant brain tumors and are highly aggressive. Invasion and migration are the main causes of poor prognosis and treatment resistance in gliomas. As migration and invasion occur, patient survival and prognosis decline dramatically. MicroRNAs (miRNAs) are small, non-coding 21–23 nucleotides involved in regulating the malignant phenotype of gliomas, including migration and invasion. Numerous studies have demonstrated the mechanism and function of some miRNAs in glioma migration and invasion. However, the biological and clinical significance (including diagnosis, prognosis, and targeted therapy) of glioma migration and invasion-related miRNAs have not been systematically discussed. This paper reviews the progress of miRNAs-mediated migration and invasion studies in glioma and discusses the clinical value of migration and invasion-related miRNAs as potential biomarkers or targeted therapies for glioma. In addition, these findings are expected to translate into future directions and challenges for clinical applications. Although many biomarkers and their biological roles in glioma invasion and migration have been identified, none have been specific so far, and further exploration of clinical treatment is still in progress; therefore, we aimed to further identify specific markers that may guide clinical treatment and improve the quality of patient survival.

Finding inhibitors and deciphering inhibitor-induced conformational plasticity in the Janus kinase via multiscale simulations

The Janus kinase (JAK) is a master regulator of the JAK/STAT pathway. Dysregulation of this signalling cascade causes neuroinflammation and autoimmune disorders. Therefore, JAKs have been characterized as an attractive target for developing anti-inflammatory drugs. Nowadays, designing efficient, effective, and specific targeted therapeutics without being cytotoxic has gained interest. We performed the virtual screening of natural products in combination with pharmacological analyses. Subsequently, we performed molecular dynamics simulations to study the stability of the ligand-bound complexes and ligand-induced inactive conformations. Notably, inactive kinases display remarkable conformational plasticity; however, ligand-induced molecular mechanisms of these conformations are still poorly understood. Herein, we performed a free energy landscape analysis to explore the conformational plasticity of the JAK1 kinase. Leonurine, STOCK1N-68642, STOCK1N-82656, and STOCK1N-85809 bound JAK1 exhibited a smooth transition from an active (αC-in) to a completely inactive conformation (αC-out). Ligand binding induces disorders in the αC-helix. Molecular mechanics Poisson Boltzmann surface area (MM/PBSA) calculation suggested three phytochemicals, namely STOCK1N-68642, Epicatechin, and STOCK1N-98615, have higher binding affinity compared to other ligand molecules. The ligand-induced conformational plasticity revealed by our simulations differs significantly from the available crystal structures, which might help in designing allosteric drugs.

Ivermectin accelerates autophagic death of glioma cells by inhibiting glycolysis through blocking GLUT4 mediated JAK/STAT signaling pathway activation

OBJECTIVE

This study aimed to investigate the regulatory effect of ivermectin (IVM) on energy metabolism in glioma progression, and provide a reference for the treatment of glioma.

METHODS

Glioma cells were treated with IVM to measure cell viability, autophagy marker protein expression, ATP content, glucose uptake, pyruvate content, and expression of key enzymes of glycolysis. Glucose transporter 4 (GLUT4) or siGLUT4 was transfected in IVM treated U87 cells to investigate the effect of GLUT4 on cellular glycolysis and autophagy. The JAK2 inhibitor AZD-1480 was introduced to explore the specific mechanism by which IVM regulates glycolysis and autophagy. Rat models of glioma xenograft were constructed and treated with 10 mg/kg IVM to observe tumor growth and examine the expression levels of GLUT4 and autophagy marker proteins in tumor tissues.

RESULTS

IVM inhibited glioma cell survival and promoted cell death. IVM promoted LC3-II protein expression and inhibited p62/SQSTM1 protein expression in glioma cells. IVM decreased adenosine-triphosphate (ATP) and pyruvate content, promoted glucose uptake, and reduced HK2 and PFK1 protein expression in U87 cells. IVM inhibited GLUT4 protein expression, and overexpression of GLUT4 promoted glycolysis and inhibited autophagic cell death in U87 cells. IVM inhibited glycolysis by blocking GLUT4 mediated the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway activation. IVM inhibited tumor growth in vivo, decreased the protein expression of GLUT4, JAK2, HK2, and PFK1 in tumor tissues, decreased the phosphorylation levels of STAT3/STAT5, and promoted the expression of autophagy marker proteins.

CONCLUSIONS

IVM accelerates autophagic death of glioma cells by inhibiting glycolysis through blocking GLUT4 mediated JAK/STAT signaling pathway activation.

PBX2-Mediated circTLK1 Activates JAK/STAT Signaling to Promote Gliomagenesis via miR-452-5p/SSR1 Axis

Glioma is considered one of the most lethal brain tumors, as the aggressive blood vessel formation leads to high morbidity and mortality rates. However, the mechanisms underlying the initiation and progression of glioma remain unclear. Here, we aimed to reveal the role of circTLK1 in glioma development. Our results revealed that circTLK1 is highly expressed in glioma tumor tissues and glioma cell lines. We then conducted a series of experiments that showed that circTLK1 was involved in the progression of gliomas. Mechanistically, investigation of the factors downstream of circTLK1 revealed that circTLK1 activated JAK/STAT signaling in glioma cells. Furthermore, AGO2-RIP, RNA-pull down, and luciferase reporter gene assays led to the identification of the novel circTLK1/miR-452-5p/SSR1 axis. Moreover, we investigated the upstream regulator of circTLK1 and found that circTLK1 expression in glioma cells could be regulated by the transcriptional factor PBX2. Taken together, our findings show that circTLK1 mediated by PBX2 activates JAK/STAT signaling to promote glioma progression through the miR-452-5p/SSR1 pathway. These results provide new insights into glioma diagnosis and therapy.

AZD3759 inhibits glioma through the blockade of the epidermal growth factor receptor and Janus kinase pathways

Glioma is an intracranial malignant tumor with high morbidity in China. Limited efficacy has been achieved in the treatment of glioma through the application of epidermal growth factor receptor (EGFR) inhibitors, which is reported to be related to the poor permeability of the brain–blood barrier (BBB) to EGFR inhibitors. AZD3759 and osimertinib are both BBB-penetrating EGFR inhibitors. The present study aimed to investigate the inhibitory effects of AZD3759 and osimertinib on glioma and compare their efficacy and the underlying mechanisms. C6 and U87 cells were incubated with different concentrations of AZD3759 (1, 2, and 4 μM) and 4 μM osimertinib, respectively. C6-LUC xenograft animals were administered different doses of AZD3759 (15, 30, and 60 mg/kg) and 60 mg/kg osimertinib. We found that proliferation was significantly suppressed and that apoptosis and cell cycle arrest were dramatically induced in both C6 and U87 cells by AZD3759 in a dose-dependent manner. Compared to AZD3759, osimertinib had inferior effects on proliferation, apoptosis, and cell cycle. In vivo experiments verified that the anti-tumor efficacy of AZD3759 against C6 xenograft tumors was dose dependent and superior to that of osimertinib. The inhibitory effects of AZD3759 on the Janus kinase (JAK)/STAT pathway were observed in both glioma cells and tumor tissues, which were more significant than those of osimertinib. In conclusion, AZD3759 may inhibit the progression of glioma via a synergistic blockade of the EGFR and JAK/STAT signaling pathways.

Correlation between the Expression of Interleukin-6, STAT3, E-Cadherin and N-Cadherin Protein and Invasiveness in Nonfunctional Pituitary Adenomas

Objective  This study aimed to investigate the expression of interleukin (IL)-6, signal transducer and activator of transcription 3 (STAT3), epithelial-cadherin (E- cadherin) and neural-cadherin (N-cadherin) proteins in nonfunctional pituitary adenomas, and their correlation with invasiveness. Methods  Thirty cases of nonfunctional pituitary adenoma pathological wax specimens were selected from our hospital, including 20 cases of invasive nonfunctional pituitary adenoma (INFPA) and 10 noninvasive nonfunctional pituitary adenomas (NNFPAs). Envision was used to detect IL-6, STAT3, E-cadherin , and N-cadherin in specimens. Statistical methods were used to analyze the correlation between the four proteins and the Knosp classification of nonfunctional pituitary adenomas. Result  IL-6 and STAT3 were highly expressed in INFPAs but poorly expressed in NNFPAs. E-cadherin expression in INFPAs was lower than that in NNFPAs. N-cadherin was positive or strongly positive in both groups. Spearman's correlation analysis showed that the expression of IL-6 and STAT3 was positively correlated with Knosp's classification, whereas the expression of E-cadherin was negatively correlated with Knosp classification. Meanwhile, the expression of N-cadherin was not correlated with Knosp's classification. Conclusion  The expression of the IL-6, STAT3, E-cadherin proteins were associated nonfunctional pituitary adenomas. However, the expression of N-cadherin was not correlated with nonfunctional pituitary adenomas.

Elevated TYROBP expression predicts poor prognosis and high tumor immune infiltration in patients with low-grade glioma

Background

Tyrosine protein tyrosine kinase binding protein (TYROBP) binds non-covalently to activated receptors on the surface of various immune cells, and mediates signal transduction and cellular activation. It is dysregulated in various malignancies, although little is known regarding its role in low-grade glioma. The aim of this study is to explore the clinicopathological significance, prognostic value and immune signature of TYROBP expression in low-grade glioma (LGG).

Methods

The differentially expressed genes (DEGs) between glioma samples and normal tissues were identified from two GEO microarray datasets using the limma package. The DEGs overlapping across both datasets were functionally annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. STRING database was used to establish the protein-protein interaction (PPI) of the DEGs. The PPI network was visualized by Cytoscape and cytoHubba, and the core module and hub genes were identified. The expression profile of TYROBP and patient survival were validated in the Oncomine, GEPIA2 and CGGA databases. The correlation between TYROBP expression and the clinicopathologic characteristics were evaluated. Gene Set Enrichment Analysis (GSEA) and single-sample GSEA (ssGSEA) were performed by R based on the LGG data from TCGA. The TIMER2.0 database was used to determine the correlation between TYROBP expression and tumor immune infiltrating cells in the LGG patients. Univariate and multivariate Cox regression analyses were performed to determine the prognostic impact of clinicopathological factors via TCGA database.

Results

Sixty-two overlapping DEGs were identified in the 2 datasets, and were mainly enriched in the response to wounding, focal adhesion, GTPase activity and Parkinson disease pathways. TYROBP was identified through the PPI network and cytoHubba. TYROBP expression levels were significantly higher in the LGG tissues compared to the normal tissues, and was associated with worse prognosis and poor clinicopathological parameters. In addition, GSEA showed that TYROBP was positively correlated to neutrophil chemotaxis, macrophage activation, chemokine signaling pathway, JAK-STAT signaling pathway, and negatively associated with gamma aminobutyric acid signaling pathway, neurotransmitter transport, neuroactive ligand receptor intersection etc. TIMER2.0 and ssGSEA showed that TYROBP expression was significantly associated with the infiltration of neutrophils, macrophages, myeloid dendritic cells and monocytes. The infiltration of the M2 phenotype macrophages, cancer-associated fibroblasts and myeloid dendritic cells correlated to worse prognosis in LGG patients. Finally, multivariate analysis showed that elevated TYROBP expression is an independent risk factor for LGG.

Conclusion

TYROBP is dysregulated in LGG and correlates with immune infiltration. It is a potential therapeutic target and prognostic marker for LGG.

Up-regulation of MARVEL domain-containing protein 1 (MARVELD1) accelerated the malignant phenotype of glioma cancer cells via mediating JAK/STAT signaling pathway

This work aimed to research the function of MARVEL domain-containing protein 1 (MARVELD1) in glioma as well as its functioning mode. Bioinformatics analysis was utilized to assess the MARVELD1 expression in glioma tissues and its relationship with grade and prognosis, based on The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Chinese Glioma Genome Atlas (CGGA) databases. Cell Counting Kit-8 (CCK-8), colony formation, and Transwell assays were carried out to determine the impact of MARVELD1 on malignant biological behavior of glioma, such as proliferation, invasion, and migration. qRT-PCR was carried out to test the mRNA level of MARVELD1. Western blot assay was performed to measure the protein expression of MARVELD1 and JAK/STAT pathway-related proteins. MARVELD1 was expressed at high levels in glioma tissues and cell lines. Kaplan-Meier survival analysis revealed that the higher MARVELD1 expression, the shorter the survival time of patients with glioma. Also, the MARVELD1 expression in WHO IV was significantly enhanced compared to that in WHO II and WHO III. Furthermore, the functional analysis of MARVELD1 in vitro revealed that knockdown of MARVELD1 in U251 cells restrained cell proliferation, migration, and invasion, while up-regulation of MARVELD1 in U87 cells presented opposite outcomes. Finally, we found that JAK/STAT signaling pathway mediated the function of MARVELD1 in glioma. MARVELD1 contributed to promoting the malignant progression of glioma, which is the key driver of activation of JAK/STAT signaling pathway in gliomas.

Expression and survival analysis of the STAT gene family in diffuse gliomas using integrated bioinformatics

Signal Transducer and Activator of Transcription (STAT) belongs to the acyltransferase family and participates in cell viability response to different cell stimuli and pathogens. By mediating the expression of a variety of genes, the STAT family plays a prominent part in mammal immunity, proliferation and differentiation. Dysregulations and mutations of STAT factors have been revealed in many kinds of cancers including diffuse gliomas; however, expression characteristic and prognostic value of STAT in diffuse gliomas remain to be elucidated. In this study, we analyzed the transcriptional and survival data of gliomas using ONCOMINE, cBioPortal, GEPIA, COXPRESDB and WEBGESTALTR databases. The results demonstrated that the transcriptional level of STAT1, STAT3 and STAT5A in gliomas was significantly higher than that in normal tissue. Furthermore, dysregulations of STAT1, STAT3, STAT4, STAT5B and STAT6 were referred to as the potential biomarkers to sub-group analysis of gliomas. Survival analysis by the Kaplan-Meier Plotter suggested that glioma patients with high expression of STAT1, STAT3 and STAT5B tended to have poor survival. These data revealed that the STAT family may be an essential aspect of glioma progression and prognosis.

Interleukin-1 receptor-associated kinase 4 as a potential biomarker: Overexpression predicts poor prognosis in patients with glioma

The undetectable onset of glioma and the difficulty of surgery lead to a poor prognosis. Appropriate biomarkers for diagnosis and treatment need to be identified. Interleukin-1 receptor-associated kinase 4 (IRAK4) is involved in the initiation and progression of cancer. However, up until now, no report has revealed the relationship between IRAK4 and glioma. The present study aimed to examine the expression of IRAK4 in glioma, and to determine if there was a relationship between IRAK4 expression and clinical outcomes or survival prognosis. Thousands of glioma tissue samples and corresponding clinical information were obtained from various databases. Then a series of bioinformatics methods were used to reveal the role of IRAK4 in glioma. Finally, reverse transcription-quantitative PCR technology was used to verify the bioinformatics results. The study found that the expression of IRAK4 was significantly increased in glioma compared with the control brain tissue samples, and IRAK4, as an independent prognostic factor, shortened the overall survival time of patients with glioma. Gene Set Enrichment Analysis showed that IRAK4 promoted the activation of cell signalling pathways, such as NOD-like and Toll-like receptor signalling pathways. Co-expression analysis showed that the expression of IRAK4 was correlated with CMTM6, MOB1A and other genes. The present study demonstrated the role of IRAK4 as an oncogene in the pathological process of glioma for the first time, and highlights the potential of IRAK4 as a biomarker for prognostic evaluation and treatment of glioma.

The Role and Therapeutic Targeting of JAK/STAT Signaling in Glioblastoma

Glioblastoma remains one of the deadliest and treatment-refractory human malignancies in large part due to its diffusely infiltrative nature, molecular heterogeneity, and capacity for immune escape. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway contributes substantively to a wide variety of protumorigenic functions, including proliferation, anti-apoptosis, angiogenesis, stem cell maintenance, and immune suppression. We review the current state of knowledge regarding the biological role of JAK/STAT signaling in glioblastoma, therapeutic strategies, and future directions for the field.

Clinicopathological and Prognostic Roles of STAT3 and Its Phosphorylation in Glioma

Glioma is defined as a common brain tumor which causes severe disability or death. As many genes are reported to relate with glioma's occurrence and development, their prognostic and therapeutic value still remains uncertain. This study aimed at investigating the association between STAT3/p-STAT3 and glioma prognosis. Nine studies (12 trials) scored ≥5 on the Newcastle-Ottawa scale were meta-analysed from the Medline, Embase, and Web of Science databases. We found that STAT3/p-STAT3 overexpression in glioma patients was associated with worse overall survival (hazard  ratio  (HR) = 1.40, 95%confidence  interval  (CI) = 1.05 ~ 1.86, P = 0.020), progression-free survival (HR = 2.05, 95%CI = 1.63 ~ 2.58, P < 0.001), and better recurrence-free survival (HR = 0.37, 95%CI = 0.15 ~ 0.95, P < 0.039). Subgroup analysis implied that STAT3/p-STAT3 overexpression was associated with worse OS in standard treatment (HR = 1.80, 95%CI = 1.06 ~ 3.04, P = 0.030), and in China (HR = 2.18, 95%CI = 1.77 ~ 2.70, P < 0.001), and metaregression analysis indicated countries (P = 0.001) may be the source of heterogeneity in our study. In conclusion, we suggested STAT3/p-STAT3 was associated with poor prognosis in patients with glioma, which indicated that STAT3/p-STAT3 might be a valuable prognostic biomarker and a promising therapeutic target for glioma.

STAT3-PTTG11 abrogation inhibits proliferation and induces apoptosis in malignant glioma cells

Pituitary tumor transforming gene 1 (PTTG11) is abundantly expressed in glioma. Our previous study demonstrated that the downregulation of PTTG11 gene expression significantly inhibited the proliferation, migration and invasion ability, and increased the apoptosis of SHG44 glioma cells. However, the molecular mechanisms that regulate PTTG11 and its actions remain elusive. In the present study, CCK-8 and flow cytometry assays were used to assess the proliferation/viability and apoptosis, respectively, of the human glioma U251 cell line. STAT3-PTTG1 signals were further evaluated by western blotting. The findings of the present study revealed that STAT3 induced PTTG11 expression, which subsequently induced downstream c-Myc and Bcl-2 expression while inhibiting Bax expression, thereby promoting cell viability and inhibiting apoptosis. PTTG11 suppression via siRNA inhibited the viability and increased the apoptosis of glioma cells induced by the STAT3 activator S3I-201. c-Myc and Bcl-2 expression was suppressed by PTTG11 inhibition. The findings of the present study suggest that the STAT3-PTTG11 signaling pathway may play an important role in glioma progression by regulating cell proliferation and apoptosis.

TROY signals through JAK1-STAT3 to promote glioblastoma cell migration and resistance

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults and carries a discouraging prognosis. Its aggressive and highly infiltrative nature renders the current standard treatment of maximal surgical resection, radiation, and chemotherapy relatively ineffective. Identifying the signaling pathways that regulate GBM migration/invasion and resistance is required to develop more effective therapeutic regimens to treat GBM. Expression of TROY, an orphan receptor of the TNF receptor superfamily, increases with glial tumor grade, inversely correlates with patient overall survival, stimulates GBM cell invasion in vitro and in vivo, and increases resistance to temozolomide and radiation therapy. Conversely, silencing TROY expression inhibits GBM cell invasion, increases sensitivity to temozolomide, and prolongs survival in a preclinical intracranial xenograft model. Here, we have identified for the first time that TROY interacts with JAK1. Increased TROY expression increases JAK1 phosphorylation. In addition, increased TROY expression promotes STAT3 phosphorylation and STAT3 transcriptional activity that is dependent upon JAK1. TROY-mediated activation of STAT3 is independent of its ability to stimulate activity of NF-κB. Inhibition of JAK1 activity by ruxolitinib or knockdown of JAK1 expression by siRNA significantly inhibits TROY-induced STAT3 activation, GBM cell migration, and decreases resistance to temozolomide. Taken together, our data indicate that the TROY signaling complex may represent a potential therapeutic target with the distinctive capacity to exert effects on multiple pathways mediating GBM cell invasion and resistance.

Abnormally high expression of HOXA2 as an independent factor for poor prognosis in glioma patients

In recent years, studies have revealed HOXA2 as a new oncogene, but its function is unknown in gliomas. We aimed to reveal the relationship between HOXA2 and glioma based on the Chinese Glioma Genome Atlas(CGGA) and the cancer genome atlas (TCGA). HOXA2 expression data and clinically relevant information of glioma patients were obtained from the CGGA and TCGA containing 1447 glioma tissues and five non-tumor brain tissues. The Wilcox or Kruskal tests were used to detect the correlation between the HOXA2 expression level and clinical data of glioma patients. the Kaplan-Meier method were used to examine the relationship between HOXA2 and overall patient survival. Gene set enrichment analysis (GSEA) was conducted to indirectly reveal the signaling pathways involved in HOXA2, and RT-PCR was used to detect HOXA2 expression in gliomas and non-tumor brain tissues. High HOXA2 expression was found to be positively correlated with clinical grade, histological type, age, and tumor recurrence, but negatively correlated with 1p19 codeletion and isocitrate dehydrogenase mutation status.RT-PCR results showed that HOXA2 expression levels were significantly higher in tumor tissues than in non-tumor brain tissues. GSEA showed that HOXA2 promoted the activation of the activation of the JAK-STAT-signaling pathway, focal adhesion, cell-adhesion-molecules-CAMS pathway, cytosolic DNA sensing pathway, and natural killer cell-mediated cytotoxicity. This study revealed for the first time that the novel oncogene,HOXA2, leads to poor prognosis in gliomas, and can be used as a biomarker for the diagnosis and treatment of gliomas.

Constitutive activation of the EGFR-STAT1 axis increases proliferation of meningioma tumor cells

Background

Meningiomas are the most frequent primary brain tumors of the central nervous system. The standard of treatment is surgery and radiotherapy, but effective pharmacological options are not available yet. The well-characterized genetic background stratifies these tumors in several subgroups, thus increasing diversification. We identified epidermal growth factor receptor–signal transducer and activator of transcription 1 (EGFR–STAT1) overexpression and activation as a common identifier of these tumors.

Methods

We analyzed STAT1 overexpression and phosphorylation in 131 meningiomas of different grades and locations by utilizing several techniques, including Western blots, qPCR, and immunocytochemistry. We also silenced and overexpressed wild-type and mutant forms of the gene to assess its biological function and its network. Results were further validated by drug testing.

Results

STAT1 was found widely overexpressed in meningioma but not in the corresponding healthy controls. The protein showed constitutive phosphorylation not dependent on the JAK–STAT pathway. STAT1 knockdown resulted in a significant reduction of cellular proliferation and deactivation of AKT and ERK1/2. STAT1 is known to be activated by EGFR, so we investigated the tyrosine kinase and found that EGFR was also constitutively phosphorylated in meningioma and was responsible for the aberrant phosphorylation of STAT1. The pharmaceutical inhibition of EGFR caused a significant reduction in cellular proliferation and of overall levels of cyclin D1, pAKT, and pERK1/2.

Conclusions

STAT1–EGFR-dependent constitutive phosphorylation is responsible for a positive feedback loop that causes its own overexpression and consequently an increased proliferation of the tumor cells. These findings provide the rationale for further studies aiming to identify effective therapeutic options in meningioma.

Pivotal Role of STAT3 in Shaping Glioblastoma Immune Microenvironment

Glioblastoma belongs to the most malignant intracranial tumors characterized by indispensable growth and aggressiveness that highly associates with dismal prognosis and therapy resistance. Tumor heterogeneity that often challenges therapeutic schemes is largely attributed to the complex interaction of neoplastic cells with tumor microenvironment (TME). Soluble immunoregulatory molecules secreted by glioma cells attract astrocytes, circulating stem cells and a range of immune cells to TME, inducing a local production of cytokines, chemokines and growth factors that reprogram immune cells to inflammatory phenotypes and manipulate host’s immune response in favor of cancer growth and metastasis. Accumulating evidence indicates that these tolerogenic properties are highly regulated by the constitutive and persistent activation of the oncogenic signal transducer and activator of transcription 3 (STAT3) protein, which impairs anti-tumor immunity and enhances tumor progression. Herein, we discuss current experimental and clinical evidence that highlights the pivotal role of STAT3 in glioma tumorigenesis and particularly in shaping tumor immune microenvironment in an effort to justify the high need of selective targeting for glioma immunotherapy.

Identification of Secreted Phosphoprotein 1 (SPP1) as a Prognostic Factor in Lower-Grade Gliomas

OBJECTIVE

Secreted phosphoprotein 1 (SPP1) is an important extracellular glycoprotein that is associated with immune regulation, tumorigenesis, and cell signaling. However, the prognostic value of SPP1 in patients with glioma has not yet been clarified, especially in lower-grade gliomas. The objective of this study is to evaluate the prognostic merit of SPP1 in lower-grade gliomas.

METHODS

The messenger RNA (mRNA) expression of SPP1 in about 1000 cancer cell lines was explored by using the data from the Cancer Cell Line Encyclopedia database. The Oncomine database was mined to evaluate the mRNA expression of SPP1 in lower-grade glioma, glioblastoma, and normal brain tissues. The correlation between SPP1 mRNA expression and overall survival of patients with glioma from The Cancer Genome Atlas database was analyzed.

RESULTS

SPP1 mRNA expression of glioma was ranked as the eighth highest of all cancer cell lines in the Cancer Cell Line Encyclopedia database. The data from the Oncomine database suggested that SPP1 expression was significantly high in glioblastoma compared with normal brain tissues but was not significantly high in lower-grade glioma compared with normal brain tissue. Analysis of the RNA-Seq data from The Cancer Genome Atlas database showed that the increased SPP1 mRNA expression in lower-grade glioma was significantly associated with poor survival outcomes in patients with lower-grade glioma. Multivariate Cox regression analysis showed that SPP1 might be considered as an independent prognostic factor in lower-grade gliomas.

CONCLUSIONS

The present study showed that SPP1 overexpression is related to worse overall survival in patients with lower-grade glioma. Moreover, SPP1 could be considered as an independent factor in lower-grade gliomas.

Modulation of glioma-inflammation crosstalk profiles in human glioblastoma cells by indirubin-3'-(2,3 dihydroxypropyl)-oximether (E804) and 7-bromoindirubin-3'-oxime (7BIO)

Indirubins E804 (indirubin-3'-(2,3 dihydroxypropyl)-oximether) and 7BIO (7-Bromoindirubin-3'-oxime) are synthetic derivatives of natural indirubin, the active compound in Danggui Longhui Wan, a traditional Chinese remedy for cancer and inflammation. Herein, we explore E804 and 7BIO for their potential to modulate key pro-inflammatory genes and cytokines in LN-18 and T98G glioblastoma cells. High grade gliomas typically secrete large amounts of inflammatory cytokines and growth factors that promote tumor growth in an autocrine fashion. Inflammation is emerging as a key concern in the success of new treatment modalities for glioblastomas. Studies indicate that select indirubin derivatives bind and activate signaling of the AHR pathway, as well as inhibit cyclin-dependent kinases and STAT3 signaling. AHR signaling is involved in hematopoiesis, immune function, cell cycling, and inflammation, and thus may be a possible target for glioma treatment. To determine the significance of the AHR pathway in LN-18 and T98G glioma inflammatory profiles, and on the effects of E804 and 7BIO on these profiles, we used 6,2',4'-trimethoxyflavone (TMF), a putative selective AHR antagonist. It was confirmed that E804 and 7BIO activates the AHR leading to cyp1b1 expression, and that TMF antagonizes expression. We then employed a commercial cancer inflammation and immunity crosstalk qRT-PCR array to screen for anti-inflammatory related properties. TMF alone inhibited expression of ifng, ptsg2, il12b, tnfa, il10, il13, the balance between pd1 and pdl1, and even expression of mhc1a/b. E804 was very potent in suppressing many pro-inflammatory genes, including il1a, il1b, il12a, ptgs2, tlr4, and others. E804 also affected expression of il6, vegfa, and stat3. Conversely, 7BIO induced cox2, but suppressed a different selection of pro-inflammatory genes including nos2, tnfa, and igf1. Secretion of IL-6 protein, an iconic inflammatory cytokine, was decreased by E804. VEGF (vascular endothelial growth factor) protein secretion was upregulated by 7BIO, yet downregulated by E804 and E804 plus TMF. Thus, E804 is both an AHR ligand and regulator of important pro-inflammatory cytokines such as IL-6 and oncogene STAT3, among others. Our results point to the use of E804 and TMF in combination as a promising new treatment for glioblastoma.

Upregulated Expression of CUX1 Correlates with Poor Prognosis in Glioma Patients: a Bioinformatic Analysis

Cut-like homeobox-1 (CUX1) is expressed in the upper layer of the cortex and participates in DNA replication, cell cycle control, and DNA repair. It has been shown to be involved in the proliferation of various types of solid tumors. The aims of this study were to explore the relationship between CUX1 expression and the prognosis of glioma by performing a series of functional experiments and bioinformatic analyses. Firstly, we found that CUX1 expression levels differed among patients with different grades of gliomas, and they were significantly correlated with the prognosis of glioma patients according to an analysis of data from a public database. qRT-PCR, western blotting, and immunohistochemical analysis of CUX1 were performed to demonstrate that the expression of CUX1 was positively correlated with the glioma WHO grade (P < 0.05) and several malignant clinical pathological parameters, including Ki67 and P53mut. In addition, the multivariate Cox regression and Kaplan-Meier curves showed that CUX1 expression exerted predictive value for overall survival. Finally, to further investigate the functions of CUX1, we identified CUX1-associated genes and, though GO/KEGG analysis, their associated biological functions and signaling pathways; the results suggested that the activity of CUX1 might be exerted via the JAK-STAT pathway or other key regulators of the cell cycle to promote proliferation, inflammation, and chemotherapy resistance in glioma. Taken together, these results indicate that CUX1 is a potential biomarker of malignancy and prognosis and may serve as a potential therapeutic target for glioma patients.

High expression of GALNT7 promotes invasion and proliferation of glioma cells

Polypeptide-N-acetyl-galactosaminlytransferase 7 (GALNT7), a member of the GalNAc-transferase family, has not been previously evaluated as a prognostic factor of glioblastoma (GBM) or low-grade glioma (LGG). Based on The Cancer Genome Atlas database and bioinformatics analyses, the expression of GALNT7 was demosntrated to be higher in GBM and LGG tissues than in normal brain tissue. The expression levels of GANLT7 were associated with age, tumor grade, survival rate, disease-free survival time and overall survival time. Gene correlation and gene-set enrichment analyses suggested that GALNT7 may affect the proliferative and invasive abilities of glioma cells through multiple signaling pathways, including regulation of the actin cytoskeleton, natural killer cell-mediated cytotoxicity, the janus kinase-signal transducer and activator of transcription (STAT) signaling pathway, cell adhesion molecules and extracellular matrix receptor interaction pathways. Furthermore, 5 target genes of GALNT7 involved in these signaling pathways were identified, including Crk, Rac family small GTPase 1, STAT3, poliovirus receptor and Tenascin C. In summary, high expression of GALNT7 was associated with poor prognosis of glioma, and may be used as an effective biomarker of glioma.

The role of interleukin-6-STAT3 signalling in glioblastoma

Glioblastoma is the most common type of malignant brain tumor among adults and is currently a non-curable disease due primarily to its highly invasive phenotype, and the lack of successful current therapies. Despite surgical resection and post-surgical treatment patients ultimately develop recurrence of the tumour. Several signalling molecules have been implicated in the development, progression and aggressiveness of glioblastoma. The present study reviewed the role of interleukin (IL)-6, a cytokine known to be important in activating several pro-oncogenic signaling pathways in glioblastoma. The current study particularly focused on the contribution of IL-6 in recurrent glioblastoma, with particular focus on glioblastoma stem cells and resistance to therapy.

The role of STAT3 in glioblastoma progression through dual influences on tumor cells and the immune microenvironment

Glioblastoma multiforme (GBM) is the most aggressive form of cancer that begins within the brain; generally, the patient has a dismal prognosis and limited therapeutic options. Signal transducer and activator of transcription 3 (STAT3) is a critical mediator of tumorigenesis, tumor progression, and suppression of anti-tumor immunity in GBM. In a high percentage of GBM cells and tumor microenvironments, persistent activation of STAT3 induces cell proliferation, anti-apoptosis, glioma stem cell maintenance, tumor invasion, angiogenesis, and immune evasion. This makes STAT3 an attractive therapeutic target and a prognostic indicator in GBM. Targeting STAT3 affords an opportunity to disrupt multiple pro-oncogenic pathways at a single molecular hub. Unfortunately, there are no successful STAT3 inhibitors currently in clinical trials. However, strong clinical evidence implicating STAT3 as a major factor in GBM justifies the identification of safe and effective strategies for inhibiting STAT3.

Signal transducer and activator of transcription 3 (STAT3) promoter methylation and expression in pituitary adenoma

BACKGROUND

Pituitary adenoma (PA) is a benign brain tumor that can cause neurological, endocrinological and ophthalmological aberrations. Till now there is a need to identify factors that can influence the tumor invasiveness and recurrence. The aim of this study was to evaluate the associations between the signal transducer and activator of transcription 3 (STAT3) promoter methylation, mRNA expression and the invasiveness or recurrence of PAs and patient clinical characteristics.

METHODS

Study participants comprised of 102 subjects with a diagnosis of PA: 54 functioning and 48 non-functioning, 58 invasive and 30 non-invasive PAs and 14 relapses. The bisulfite treatment of tumor DNA and methylation-specific polymerase chain reaction (MS-PCR) method was used to determine the STAT3 gene promoter methylation. For the STAT3 mRNA expression, the first-strand cDNA was produced from total RNA by using reverse transcriptase and quantitative real-time PCR (qRT-PCR) was performed.

RESULTS

In 10.78% (11/102) of PA tissues STAT3 gene promoter was methylated. A gender of male and patient group older than 60 years were significantly associated with reduced STAT3 mRNA expression (Mann-Whitney test, p = 0.025, p = 0.047, respectively). However, no more statistical differences were found between STAT3 promoter methylation, mRNA expression and patient clinical characteristics or PA invasiveness or recurrence.

CONCLUSIONS

Further investigations are needed to clarify the influence of STAT3 gene promoter methylation and mRNA expression changes in PAs.

CUEDC2 suppresses glioma tumorigenicity by inhibiting the activation of STAT3 and NF-κB signaling pathway

CUEDC2, a CUE domain containing 2 protein, plays critical roles in many biological processes, such as cell cycle, inflammation and tumorigenesis. However, whether CUEDC2 was involved in tumorigenesis of glioma and the possible mechanism remains to be elucidated. In the present study, our results implied that the expression of CUEDC2 was lower in the glioma tissue and glioma cell lines than that of normal tissue and asctrocyte cells. Downregulation of endogenous CUEDC2 in glioma U251 cell lines by RNAi promoted the tumor cells proliferation, migration, invasion and glioma neurosphere formation, while, overexpression of CUEDC2 showed the opposite effect. Further studies showed that overexpression of CUEDC2 suppressed the activation and nuclear translocation of phosphorylated-STAT3 (p-STAT3) but the level of p-STAT3 increased after interfering with the expression of CUEDC2. Moreover, CUEDC2 expression has an inhibitory effect on the activation of NF-κB. Thus, our studies suggested that the decreased expression of CUEDC2 in glioma led to the activation of transcription factor STAT3 and NF-κB signaling pathway which may be related to the tumorigenicity in glioma.

Prioritizing cancer-related microRNAs by integrating microRNA and mRNA datasets

MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of target genes, and they are involved in cancer initiation and progression. Even though many cancer-related miRNAs were identified, their functional impact may vary, depending on their effects on the regulation of other miRNAs and genes. In this study, we propose a novel method for the prioritization of candidate cancer-related miRNAs that may affect the expression of other miRNAs and genes across the entire biological network. For this, we propose three important features: the average expression of a miRNA in multiple cancer samples, the average of the absolute correlation values between the expression of a miRNA and expression of all genes, and the number of predicted miRNA target genes. These three features were integrated using order statistics. By applying the proposed approach to four cancer types, glioblastoma, ovarian cancer, prostate cancer, and breast cancer, we prioritized candidate cancer-related miRNAs and determined their functional roles in cancer-related pathways. The proposed approach can be used to identify miRNAs that play crucial roles in driving cancer development, and the elucidation of novel potential therapeutic targets for cancer treatment.

Principles of immunotherapy

Gliomas are the most common primary brain tumors of the central nervous system, and carry a grim prognosis. Novel approaches utilizing the immune system as adjuvant therapy are quickly emerging as viable and effective options. Immunotherapeutic strategies being investigated to treat glioblastoma include: vaccination therapy targeted against either specific tumor antigens or whole tumor lysate, adoptive cellular therapy with cytotoxic T lymphocytes, chimeric antigen receptors and bi-specific T-cell engaging antibodies allowing circumvention of major histocompatibility complex restriction, aptamer therapy with aims for more efficient target delivery, and checkpoint blockade in order to release the tumor-mediated inhibition of the immune system. Given the heterogeneity of glioblastoma and its ability to gain mutations throughout the disease course, multifaceted treatment strategies utilizing multiple forms of immunotherapy in combination with conventional therapy will be most likely to succeed moving forward.

An Eighteen Serum Cytokine Signature for Discriminating Glioma from Normal Healthy Individuals

Glioblastomas (GBM) are largely incurable as they diffusely infiltrate adjacent brain tissues and are difficult to diagnose at early stages. Biomarkers derived from serum, which can be obtained by minimally invasive procedures, may help in early diagnosis, prognosis and treatment monitoring. To develop a serum cytokine signature, we profiled 48 cytokines in sera derived from normal healthy individuals (n = 26) and different grades of glioma patients (n = 194). We divided the normal and grade IV glioma/GBM serum samples randomly into equal sized training and test sets. In the training set, the Prediction Analysis for Microarrays (PAM) identified a panel of 18 cytokines that could discriminate GBM sera from normal sera with maximum accuracy (95.40%) and minimum error (4.60%). The 18-cytokine signature obtained in the training set discriminated GBM sera from normal sera in the test set as well (accuracy 96.55%; error 3.45%). Interestingly, the 18-cytokine signature also differentiated grade II/Diffuse Astrocytoma (DA) and grade III/Anaplastic Astrocytoma (AA) sera from normal sera very efficiently (DA vs. normal–accuracy 96.00%, error 4.00%; AA vs. normal–accuracy 95.83%, error 4.17%). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using 18 cytokines resulted in the enrichment of two pathways, cytokine-cytokine receptor interaction and JAK-STAT pathways with high significance. Thus our study identified an 18-cytokine signature for distinguishing glioma sera from normal healthy individual sera and also demonstrated the importance of their differential abundance in glioma biology.

Nucleophosmin overexpression is associated with poor survival in astrocytoma

The multiple functions of the protein nucleophosmin (NPM) include the regulation and balance of cell growth, proliferation, and apoptosis. Many cancers have suspected associations with overexpression of NPM or with mutation of the NPM gene. Although NPM and anaplastic lymphoma kinase fusion proteins are known to be related to the Janus Kinase/Signal Transduction and Activator of Transcription (JAK/STAT) signaling pathway, the relationships of NPM, JAK2, and STAT5 to astrocytoma remain unclear. Therefore, this study performed histochemical analyses of expressions of NPM, p-JAK2, and STAT5B proteins in patients with astrocytoma. The results showed that high NPM expression was significantly associated with high tumor grade (p = 0.000), old age (p = 0.000), low Karnofsky Performance Scale (KPS) score (p = 0.000), and tumor recurrence (p = 0.045). High p-JAK2 expression was significantly associated with old age (p = 0.000), high tumor grade (p = 0.000), low KPS score (p = 0.000), and tumor recurrence (p = 0.036). Expression of STAT5B was significantly correlated with tumor grade (p = 0.018) and KPS score (p = 0.002). High expressions of NPM, p-JAK2, and STAT5B were associated with a short survival time (p = 0.035, 0.003 and 0.002, respectively). In multivariable analysis, STAT5B expression was a significant predictor of survival time (p = 0.003). In conclusion, NPM and p-JAK2/STAT5B may have important roles in tumor progression, and STAT5B is an independent prognostic marker of astrocytoma.

Review of STAT3 (Signal Transducers and Activators of Transcription) in head and neck cancer

STATs can be activated independently of JAKs, most notably by c-Src kinases. In cancer cells, STAT3 and STAT5 activation leads to the increased expression of downstream target genes, leading to increased cell proliferation, cell survival, angiogenesis, and immune system evasion. STAT3 and STAT5 are expressed and activated in head and neck squamous cell carcinoma where they contribute to cell survival and proliferation. STATs can be activated by a number of signal transduction pathways, including the epidermal growth factor receptor (EGFR), nicotinic receptor, interleukin (IL) receptor, and erythropoietin receptor pathways. Identifying agents that inhibit STAT-3, a cytosolic transcription factor involved in the activation of various genes implicated in tumor progression is a promising strategy for cancer chemoprevention. Several approaches have been used to inhibit STAT3 in the hope of developing an antitumor agent. Although several STAT3-specific agents are promising, none are in clinical development, mostly because of drug delivery and stability issues.

The role of STAT3 in tumor-mediated immune suppression

The role of tumor-induced immune modulation in cancer progression is currently a focus of investigation. The signal transducer and activator of transcription 3 (STAT3) is an established molecular hub of immunosuppression, and its signaling pathways are classically overactivated within malignancies. This article will review STAT3 operational mechanisms within the immune system and the tumor microenvironment, with a focus on therapeutic strategies that may impact outcomes for patients with cancer.

A positive feedback loop between prolactin and STAT5 promotes angiogenesis

The signal transduction events that orchestrate cellular activities required for angiogenesis remain incompletely understood. We and others recently described that proangiogenic mediators such as fibroblast growth factors can activate members of the signal transducers and activators of transcription (STAT) family. STAT5 activation is necessary and sufficient to induce migration, invasion and tube formation of endothelial cells. STAT5 effects on endothelial cells require the secretion of the prolactin (PRL) family member proliferin-1 (PLF1) in mice and PRL in humans. In human endothelial cells, PRL activates the PRL receptor (PRLR) resulting in MAPK and STAT5 activation, thus closing a positive feedback loop. In vivo, endothelial cell-derived PRL is expected to combine with PRL of tumor cell and pituitary origin to raise the concentration of this polypeptide hormone in the tumor microenvironment. Thus, PRL may stimulate tumor angiogenesis via autocrine, paracrine, and endocrine pathways. The disruption of tumor angiogenesis by interfering with PRL signaling may offer an attractive target for therapeutic intervention.

Astaxanthin inhibits JAK/STAT-3 signaling to abrogate cell proliferation, invasion and angiogenesis in a hamster model of oral cancer

Identifying agents that inhibit STAT-3, a cytosolic transcription factor involved in the activation of various genes implicated in tumour progression is a promising strategy for cancer chemoprevention. In the present study, we investigated the effect of dietary astaxanthin on JAK-2/STAT-3 signaling in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis model by examining the mRNA and protein expression of JAK/STAT-3 and its target genes. Quantitative RT-PCR, immunoblotting and immunohistochemical analyses revealed that astaxanthin supplementation inhibits key events in JAK/STAT signaling especially STAT-3 phosphorylation and subsequent nuclear translocation of STAT-3. Furthermore, astaxanthin downregulated the expression of STAT-3 target genes involved in cell proliferation, invasion and angiogenesis, and reduced microvascular density, thereby preventing tumour progression. Molecular docking analysis confirmed inhibitory effects of astaxanthin on STAT signaling and angiogenesis. Cell culture experiments with the endothelial cell line ECV304 substantiated the role of astaxanthin in suppressing angiogenesis. Taken together, our data provide substantial evidence that dietary astaxanthin prevents the development and progression of HBP carcinomas through the inhibition of JAK-2/STAT-3 signaling and its downstream events. Thus, astaxanthin that functions as a potent inhibitor of tumour development and progression by targeting JAK/STAT signaling may be an ideal candidate for cancer chemoprevention.

WWOX modulates the gene expression profile in the T98G glioblastoma cell line rendering its phenotype less malignant

The aim of the present study was to assess the influence of WWOX gene upregulation on the transcriptome and phenotype of the T98G glioblastoma cell line. The cells with high WWOX expression demonstrated a significantly different transcription profile for approximately 3,000 genes. The main cellular pathways affected were Wnt, TGFβ, Notch and Hedgehog. Moreover, the WWOX-transfected cells proliferated at less than half the rate, exhibited greatly lowered adhesion to ECM, increased apoptosis and impaired 3D culture formation. They also demonstrated an increased ability for crossing the basement membrane. Our results indicate that WWOX, apart from its tumor-suppressor function, appears to be a key regulator of the main cellular functions of the cell cycle and apoptosis. Furthermore, our results showed that WWOX may be involved in controlling metabolism, cytoskeletal structure and differentiation.

STAT transcription factors in normal and cancer stem cells

Signal transducer and activator of transcription proteins (STATs) play vital roles in the regulation of cellular proliferation and survival in normal hematopoietic cells, including hematopoietic stem cells. However, aberrant activation of STATs is commonly observed in a number of hematologic malignancies, and recent studies indicate that targeting of STATs may have therapeutic benefit in these diseases. Additional studies have provided greater understanding of the cells responsible for leukemia initiation, referred to as leukemia stem cells. Emerging evidence indicates that STATs are important in maintaining leukemia stem cells and represent a promising target for eradication of this dangerous cell population. Here we summarize what is known about normal hematopoietic stem cells and the origin of leukemic stem cells. We further describe the roles of STAT proteins in these cell populations, as well as current progress toward the development of novel agents and strategies for targeting the STAT proteins.

STAT3 Activation in Glioblastoma: Biochemical and Therapeutic Implications

Signal transducer and activator of transcription 3 (STAT3) is a potent regulator of gliomagenesis through its induction of angiogenesis, host immunosuppression, and tumor invasion. Gain of function mutations result in constitutive activation of STAT3 in glioma cells, making STAT3 an attractive target for inhibition in cancer therapy. Nevertheless, some studies show that STAT3 also participates in terminal differentiation and apoptosis of various cell lines and in glioma with phosphatase and tensin homolog (PTEN)-deficient genetic backgrounds. In light of these findings, the utility of STAT3 as a prognostic indicator and as a target of drug therapies will be contingent on a more nuanced understanding of its pro- and anti-tumorigenic effects.

JAK-STAT signaling in stem cells

Adult stem cells are essential for the regeneration and repair of tissues in an organism. Signals from many different pathways converge to regulate stem cell maintenance and differentiation while preventing overproliferation. Although each population of adult stem cells is unique, common themes arise by comparing the regulation of various stem cell types in an organism or by comparing similar stem cell types across species. The JAK-STAT signaling pathway, identified nearly two decades ago, is now known to be involved in many biological processes including the regulation of stem cells. Studies in Drosophila first implicated JAK-STAT signaling in the control of stem cell maintenance in the male germline stem cell microenvironment, or niche; subsequently it has been shown play a role in other niches in both Drosophila and mammals. In this chapter, we will address the role of JAK-STAT signaling in stem cells in the germline, intestinal, hematopoietic and neuronal niches in Drosophila as well as the hematopoietic and neuronal niches in mammals. We will comment on how the study of JAK-STAT signaling in invertebrate systems has helped to advance our understanding of signaling in vertebrates. In addition to the role of JAK- STAT signaling in stem cell niche homeostasis, we will also discuss the diseases, including cancers, that can arise when this pathway is misregulated.