Occurrence Of Glioma Research Articles

Identification of the Role and Clinical Prognostic Value of Target Genes of m6A RNA Methylation Regulators in Glioma.

m6A RNA methylation regulators can regulate the growth, progression, and invasion of glioma cells by regulating their target genes, which provides a reliable support for the m6A regulator–target axes as the novel therapeutic targets and clinical prognostic signature in glioma. This study aimed to explore the role and prognostic value of m6A RNA methylation regulators and their targets. Expression profiles and clinicopathological data were obtained from the Chinese Glioma Genome Atlas (CGGA), The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Clinical Proteome Tumor Analysis Consortium (CPTAC) datasets. Differential expression and correlation analyses were performed between normal and glioma tissues at mRNA and protein levels. Univariate Cox regression, survival, and Lasso Cox regression analyses were conducted to identify and establish the prognostic gene signature. Kaplan–Meier curve, multivariate Cox regression analysis, and ROC were utilized to evaluate the prognostic capacity of the prognostic gene signature. The correlation analysis, systematic bioinformatics analysis, and cell experiment were performed to further understand the potential underlying molecular mechanisms and drug sensitivity. Our results suggested that IGF2BP2, KIAA1429, METTL16, and METTL3, as well as 208 targets are involved in the occurrence of glioma, GBM, and LGG. YTHDF1 and 78 targets involved the occurrence of glioma and GBM, not LGG, among which 181 genes were associated with overall survival. From other findings and our cell experiment results, we demonstrated that METTL3 can activate Notch pathway and facilitate glioma occurrence through regulating its direct targets NOTCH3, DLL3, and HES1, and Notch pathway genes may serve as the potential treatment targets for glioma. Our study established and validated a seven-gene signature comprising METTL3, COL18A1, NASP, PHLPP2, TIMP1, U2AF2, and VEGFA, with a good capability for predicting glioma survival, which may guide therapeutic customization and clinical decision-making. These genes were identified to influence 81 anticancer drug responses, which further contributes to the early phase clinical trials of drug development.

The Role of Exosomal miRNAs in Glioma: Biological Function and Clinical Application.

Gliomas are complex and heterogeneous central nervous system tumors with poor prognosis. Despite the increasing development of aggressive combination therapies, the prognosis of glioma is generally unsatisfactory. Exosomal microRNA (miRNA) has been successfully used in other diseases as a reliable biomarker and even therapeutic target. Recent studies show that exosomal miRNA plays an important role in glioma occurrence, development, invasion, metastasis, and treatment resistance. However, the association of exosomal miRNA between glioma has not been systemically characterized. This will provide a theoretical basis for us to further explore the relationship between exosomal miRNAs and glioma and also has a positive clinical significance in the innovative diagnosis and treatment of glioma.

A Risk Signature Consisting of Eight m6A Methylation Regulators Predicts the Prognosis of Glioma.

Glioma progression seriously correlates to the epigenetic context. This study aims to identify glioma subtypes by clustering analysis of patients using the multi-omics data of N6-methyladenosine (m6A) methylation regulators and to construct a risk signature for investigating the role of m6A methylation regulators in the prognosis of glioma. Multi-omics data of glioma and normal control tissues were obtained through The Cancer Genome Atlas (TCGA) database. The clustering analysis of multi-omics data of patients was conducted using the R package iClusterPlus software. The risk model was constructed by univariate and multivariate Cox analysis, and the glioma expression data and related clinical data were obtained by Chinese Glioma Genome Atlas (CGGA) datasets to verify the risk model. By analyzing the glioma data in TCGA, we found that the risk signature could be constructed according to the eight genes with m6A methylation modification function, including ALKBH5, HNRNPA2B1, IGF2BP2, IGF2BP3, RBM15, WTAP, YTHDF1, and YTHDF2. Meanwhile, we found that IGF2BP2 and IGF2BP3 were highly expressed in glioma subtypes with high-risk scores and closely related to the prognosis of glioma patients. m6A methylation regulators, especially IGF2BP2 and IGF2BP3, play important roles in the malignant progression of glioma. The risk signature constructed by eight m6A methylation regulators can predict the prognosis of glioma. IGF2BP2 and IGF2BP3 may be the key regulatory factors of m6A methylation regulators involved in the occurrence and development of glioma, and can serve as molecular markers for the prognosis of glioma.

Expression Profiles and Bioinformatics Analysis of Full-length circRNA Isoforms in Gliomas

Background: Circular RNAs (circRNAs) are a newly discovered type of non-coding RNA, which have been demonstrated to act as microRNA (miRNA) “sponges” to modulate gene expression. Emerging evidence has confirmed that circRNAs take part in many biological processes in a variety of malignant tumors, including gliomas, suggesting that they could serve as biomarkers or therapeutic targets for tumors. The purpose of this study was to explore the roles of circRNAs in gliomas and to provide valuable clues for clinical diagnosis and treatment. Methods: RNA-seq data with poly(A)-/RNase R treatment was employed to investigate the expression profiles of circRNAs in tumor and paracancerous tissues derived from glioma patients. CircAST was used for full-length circRNA reconstruction and quantification. Bioinformatics analyses, including GO enrichment and KEGG pathway analyses, were performed to reveal the potential biological process and pathways of their host genes. A circRNA-miRNA interaction network was constructed to depict the interactions of the dysregulated circRNA transcripts with miRNAs. Results: A total of 20,474 circular transcripts that originated from 16,022 circRNAs were successfully reconstructed in the samples. We detected 646 upregulated and 112 downregulated circular transcripts in tumor tissues compared with paracancerous tissues. GO analysis revealed that their host genes may be related to positive regulation of GTPase activity, regulation of synaptic transmission, and glutamatergic and dendrite morphogenesis in the cytoplasm and cytosol. KEGG pathway analysis showed that the glutamatergic synapse, neurotrophin signaling pathway, and ErbB signaling pathway may be linked to the occurrence and development of gliomas. Conclusion: Our study revealed a comprehensive profile of differentially expressed circRNA transcripts in gliomas, indicating that aberrantly expressed circRNAs might play important roles in the occurrence and development of human gliomas.

Decreased Expression of PACSIN1 in Brain Glioma Samples Predicts Poor Prognosis.

Gliomas are the most severe brain tumours with a poor prognosis. Although surgery, postoperative radiotherapy and chemotherapy can improve the survival rate of glioma patients, the prognosis of most glioma patients is still poor. In recent years, the influence of gene-targeted therapy on gliomas has been gradually discovered, and intervening the occurrence and development of brain gliomas from the perspective of the gene will significantly improve treatment prognosis. Protein Kinase C and Casein Kinase Substrate in Neurons 1 (PACSIN1) is a member of the conserved peripheral membrane protein family in eukaryotes. Improper expression of PACSIN1 can lead to neurological diseases such as Huntington’s disease and schizophrenia. However, its relationship with tumours or even gliomas has not been explored. The study aims to explore PACSIN1 as a prognostic factor that can predict overall survival (OS) for gliomas. We collected the data from CGGA, TCGA, GEO databases and the pathological glioma tissue specimens from 15 clinical glioma patients surgically resected. The differential expression of PACSIN1 in various clinical indicators, the genes related to PACSIN1 expression, the prognostic value of PACSIN1 and the functional annotations and pathway analysis of differently expressed genes (DEGs) were analysed. The results revealed that PACSIN1 had low expression levels in grade IV, IDH1 wild-type and 1p/19q non-codel group gliomas, and PACSIN1 was considered a mesenchymal molecular subtype marker. PACSIN1 expression is positively correlated with OS in all gliomas and it was found that PACSIN1 influenced the occurrence and development of gliomas through synaptic transmission. The PACSIN1 expression is negatively correlated with the malignant degree of gliomas and positively associated with the OS, indicating that PACSIN1 would play an essential role in the occurrence and development of gliomas and might be a potential new biomarker and targeted therapy site for gliomas.

Tat-NTS Suppresses the Proliferation, Migration and Invasion of Glioblastoma Cells by Inhibiting Annexin-A1 Nuclear Translocation.

Prevention of the nuclear translocation of ANXA1 with Tat-NTS was recently reported to alleviate neuronal injury and protect against cerebral stroke. However, the role that Tat-NTS plays in the occurrence and development of gliomas still needs to be elucidated. Therefore, human glioblastoma (GB) cells were treated with various concentrations of Tat-NTS for 24h, and cell proliferation, migration and invasion were assessed with CCK-8 and Transwell assays. The nuclear translocation of ANXA1 was evaluated by subcellular extraction and immunofluorescence, and protein expression levels were detected by Western blot analysis. In addition, the activity of MMP-2/9 was measured by gelatin zymography. The results revealed that Tat-NTS significantly inhibited the nuclear translocation of ANXA1 in U87 cells and inhibited the proliferation, migration and invasion of GB cells. Tat-NTS also suppressed cell cycle regulatory proteins and MMP-2/-9 activity and expression. Moreover, Tat-NTS reduced the level of p-p65 NF-κB in U87 cells. These results suggest that the Tat-NTS-induced inhibition of GB cell proliferation, migration and invasion is closely associated with the induction of cell cycle arrest, downregulation of MMP-2/-9 expression and activity and suppression of the NF-κB signaling pathway. Thus, Tat-NTS may be a potential chemotherapeutic agent for the treatment of GB.

IRF7 as an Immune-Related Prognostic Biomarker and Associated with Tumor Microenvironment in Low-Grade Glioma.

PurposeTumor microenvironment (TME) affects the occurrence and progression of low-grade glioma (LGG). The aim of this study is to identify TME-related genes that influence prognosis in LGG patients and to explore their function and role in tumor immunity.Patients and MethodsThe TME components of LGG samples in the Cancer Genome Atlas (TCGA) database were identified by the ESTIMATE method, and differentially expressed genes (DEGs) with significant differences in immune scores and stromal scores were screened out. The core genes of DEGs were screened out by protein–protein interaction (PPI) network. Furthermore, immune-related target genes significantly correlated with prognosis were identified. Survival analysis and correlation analysis showed the correlation between target genes and clinical features and prognosis. The expression differences of target genes were verified by external database Chinese Glioma Genome Atlas (CGGA). CIBERSORT software identified the proportion of tumor-infiltrating immune cells (TICs) that were significantly related to target genes. Gene set enrichment analysis (GSEA) could enrich the main functions related to high and low expression of target genes.ResultsA total of 1567 DEGs were screened out from 529 LGG samples in the TCGA database, and 146 immune-related genes affecting prognosis were found. A total of 403 core genes were obtained from PPI network. The target gene interferon regulatory factor 7 (IRF7) was significantly associated with prognosis and clinical features of the tumor. The CGGA database verified the relationship between high and low expression groups of IRF7 and prognosis. GSEA indicated that IRF7 was mainly enriched in immune-related activities, significantly correlated with T cells CD8, macrophages M1, macrophages M2 and monocytes.ConclusionThe IRF7 is involved in immune responses in TME of LGG, which in turn influenced tumor occurrence and progression. IRF7 can act as a potential biomarker for prognosis in patients with LGG and provide a target for tumor immunotherapy.

Investigation of the Relationship between CMYC Gene Polymorphisms and Glioma Susceptibility in Chinese Children

Glioma is a common central nervous system tumors in children. CMYC has a range of functions that are disrupted in various tumor cells, and may contribute to the occurrence and development of glioma. Two CMYC single nucleotide polymorphisms (rs4645943C>T and rs2070583 A>G) were genotyped in 190 cases and 248 controls from Wenzhou and Guangzhou hospitals. After adjusting for age and sex, odds ratio and 95% confidence interval values were calculated by logistic regression to evaluate the correlation between CMYC gene polymorphisms and glioma risk; no significant associations were detected. These results require future validation in a larger sample cohort.

Retraction.

Retraction: "Down-regulation of the long noncoding RNA-HOX transcript antisense intergenic RNA inhibits the occurrence and progression of glioma," by Bin Yang, Zhen-Yu Wei, Bang-Qing Wang, Hua-Chao Yang, Jun-Yi Wang, Xing-Yao Bu, J Cell Biochem. 2018; 2278-2287: The above article, published online on 31 August 2017 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/10.1002/jcb.26390) has been retracted by agreement between the the journal's Editor in Chief, Prof. Dr. Christian Behl, and Wiley Periodicals LLC. The retraction has been agreed following an investigation based on allegations raised by a third party. As several flaws and inconsistencies between results presented and experimental methods described were found, the editors consider the conclusions of this article to be invalid.

Occurrence of Chordoid Glioma With Sodium Ion Metabolism Disorder 5 Years After Meningioma Surgery and Whole-Exome Sequencing: A Case Report and Literature Review

Chordoid glioma (CG), a rare slow-growing brain tumor, mainly occurs in the region of the third ventricle. Although its degree of malignancy is relatively low, its clinical prognosis is poor due to obscure clinical manifestations and the particular growing position. Currently, gross total resection is the best available method for treatment of CG. However, the tumor is located in the deep structure of the brain and close to neurovascular structure so it is difficult to remove completely. This study reported a case of CG of the third ventricle 5 years after surgery of right frontal parietal fibrous meningioma, accompanied with peri and post-operative sodium ion metabolism disorder. Whole-exome sequencing (WES) revealed 25 gene mutations shared by meningioma and CG. In addition, the PRKCAD463H CG marker gene mutation also existed in this patient. We reviewed the latest literature on this rare brain tumor, summarized its clinical manifestations, imaging and pathological characteristics, and discussed the mechanism related to its occurrence and the reasons for sodium ion disorder.

Circular RNA circitga7 accelerates glioma progression via miR-34a-5p/VEGFA axis.

Circular RNAs (circRNAs) are a group of noncoding RNAs derived from back-splicing events. CircRNA is reported to be involved in various tumor progressions, including glioma. Although there are a few reports of circular RNAs participating in gliomas, it is still unclear whether circular RNAs regulate the occurrence of gliomas. In our research, we found that the expression of circITGA7 in glioma tissues and glioma cells increased significantly. Knocking down circITGA7 can significantly inhibit the proliferation of glioma cells and reduce cell metastasis. Through analysis and dual-luciferase report assay, we found that circITGA7 acts as a sponge for miR-34a-5p targeting VEGFA in glioma. Our study showed that circITGA7 regulates the proliferation and metastasis of glioma cell lines (SW1783&U373) by regulating the miR-34a-5p/VEGFA pathway. In conclusion, our study revealed a regulatory loop for the circITGA7/miR-34a-5p/VEGFA axis to regulate glioma development.

Remodelling and Treatment of the Blood-Brain Barrier in Glioma.

The blood-brain barrier (BBB) is an essential structure of the central nervous system (CNS), and its existence makes the local internal environment of the CNS a relatively independent structure distinct from other internal environments of the human body to ensure normal physiological and high stability of activities of the CNS. Changes in BBB structure and function are fundamental to the pathophysiology of many diseases. The occurrence and development of glioma are often accompanied by a series of changes in the structure and function of the internal environment, the most significant of which is remodelling of the BBB. The remodelling of the BBB usually leads to changes in the permeability of local microvessels, which provide certain favourable conditions for the occurrence and development of glioma. Meanwhile, the newly generated abnormal blood vessels and the remaining intact regions of the BBB also hinder the effects of drug treatments. Changes in permeability and structural function often lead to the creation of abnormally functioning vascular regions, which pose further treatment challenges. At present, therapeutic methods for glioma have not achieved satisfactory effects in clinical practice, and emerging therapeutic methods have not yet been widely used in clinical practice. In this review, we summarize the knowledge of remodelling of the BBB in the glioma environment, the type of changes that occur, and current BBB treatment methods and prospects for the treatment of glioma.

Hsa_circ_0080229 upregulates the expression of murine double minute-2 (MDM2) and promotes glioma tumorigenesis and invasion via the miR-1827 sponging mechanism.

BackgroundGlioma is the most common and fatal primary cranial tumor. The epidermal growth factor receptor (EGFR) plays an important role in the occurrence and treatment of glioma, which might function through a circular ribonucleic acid (circRNA)-related mechanism. Hsa_circ_0080229 (circ_0080229) has been identified as a circRNA arising from an EGFR gene in gliomas; however, little is known about its molecular mechanism to date.MethodsTo address this question, a series of experiments were conducted to confirm the effect of circ_0080229 in gliomas and identify the downstream mechanism. A quantitative real-time polymerase chain reaction (qRT-PCR) analysis and in-situ hybridization/fluorescence in-situ hybridization (ISH/FISH) testing were performed to identify the expression of circ_0080229 in patient samples. Bioinformatic analysis was carried out to explore the possible mechanism. Next, a series of in-vitro functional assays and in-vivo assays with a xenograft subcutaneous glioma model was carried out to confirm the effect of circ_0080229. Finally, qRT-PCR analysis and a Western Blot analysis were performed to verify the related mechanism.ResultsThe expression of circ_0080229 was upregulated in both glioma tissues and cell lines related to unfavorable clinicopathologic characteristics. The expression of circ_0080229 was found to be inversely correlated with miR-1827, a micro-ribonucleic acid (miRNA) targeting murine double minute-2 (MDM2). The downregulation of circ_0080229 inhibited gliomas in vivo and suppressed U87 and U251 cell lines in vitro, which the transfection of the miR-1827 inhibitor could reverse. Concerning the mechanism, a block of circ_0080229 decreased MDM2 expression, while the inhibition of miR-1827 reversed this effect. Thus, circ_0080229 appears to target the downstream miR-1827/MDM2 signaling pathway.ConclusionsOur results showed that the silencing of circ_0080229 upregulates the expression of miR-1827, which in turn resulted in the suppression of MDM2, and the mediation of the downstream P53 signaling pathway. Circ_0080229 exerted an effect in mediating tumor progression through the MDM2 signaling pathway by sponging miR-1827. Its importance as a potential prognostic biomarker in gliomas has thus been established.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Potential new targets and drugs related to histone modifications in glioma treatment

Glioma accounts for 40–50% of craniocerebral tumors, whose outcome rarely improves after standard treatment. The development of new therapeutic targets for glioma treatment has important clinical significance. With the deepening of research on gliomas, recent researchers have found that the occurrence and development of gliomas is closely associated with histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination. Additionally, evidence has confirmed the close relationship between histone modifications and temozolomide (TMZ) resistance. Therefore, histone modification-related proteins have been widely recognized as new therapeutic targets for glioma treatment. In this review, we summarize the potential histone modification-associated targets and related drugs for glioma treatment. We have further clarified how histone modifications regulate the pathogenesis of gliomas and the mechanism of drug action, providing novel insights for the current clinical glioma treatment. Herein, we have also highlighted the limitations of current clinical therapies and have suggested future research directions and expected advances in potential areas of disease prognosis. Due to the complicated glioma pathogenesis, in the present review, we have acknowledged the limitations of histone modification applications in the related clinical treatment.

Histomorphological and Immunohistochemical Analysis of Gliomas

In the present study, important parameters like frequency distribution of Gliomas, age group of Glioma patients, common sex involved, commonest site of occurrence, clinical presentations, radiological histopathological correlation, p16INK4a expression of the glial tumors are compared with other similar studies. The aim is to find out common age group of Glioma occurrence and it includes higher grades of Astrocytomas. The present study focuses on common symptoms such as head ache, histopathologial correlation and common tumor etc and to study the Histomorphology of Gliomas to evaluate p16INK4a expression in Gliomas to correlate the p16INK4a expression with the WHO grading of Gliomas. Various parameters like age, sex, site, clinical symptoms, radiological correlation and WHO Grading were analysed.p16 IHC was expressed as positive and negative according to its nuclear staining of >25% cells in 10 continuous fields in 40x and it was found that p16 expression was Positive in all Grade 1 Astrocytoma, 3 out of 5 Grade II Astrocytoma and only in one Grade IV Glioblastoma. p16 expression was negative in 2 Grade II Astrocytomas and in 17 Grade IV Gioblastomas and in 2 cases of Myxopapillary Ependymoma.

Decreased Expression of PACSIN1 in Brain Glioma Samples Predicts Poor Prognosis

Background: Gliomas are the most severe brain tumours with a poor prognosis. The study aims to explore PACSIN1 as a prognostic factor that can predict overall survival (OS) for Gliomas. Methods: We collected the data from CGGA, TCGA, GEO databases and the pathological glioma tissue specimen s from 15 clinical glioma patients surgically resected . The differential expression of PACSIN1 in various clinical indicators, the genes related to PACSIN1 expression, the prognostic value of PACSIN1 and the functional annotations and pathway analysis of differently expressed genes (DEGs) were analysed. Findings: PACSIN1 was low expressed in grade IV, IDH1 wild-type and 1p/19q non-codel group gliomas, and PACSIN1 was considered a mesenchymal marker molecular subtype. PACSIN1 expression is positively correlated with OS in all gliomas and it was found that PACSIN1 influenced the occurrence and development of gliomas through synaptic transmission. Interpretation: The PACSIN1 expression is negatively correlated with the malignant degree of gliomas and positively associated with the OS, indicating that PACSIN1 would play an essential role in the occurrence and development of gliomas and might be a potential new biomarker and targeted therapy site for gliomas. Funding: The work was supported by the Dominant Discipline Program for Nursing (No. JX10631803, 2018-2021), the Science and Technology Development Fund of Nanjing Medical University (No. NMUB2019024), Science and Technology - Basic Research Project of Medical and Health Application of Suzhou China (No. SYS2018089), and Science and Technology Project of Suzhou Health and Family Planning Commission (NO. LCZX201913). Declaration of Interests: The authors declare no potential conflicts of interest. Ethics Approval Statement: This study was approved by the Ethics Committee of Nanjing Medical University.

Immunogenomic Profiling Demonstrate AC003092.1 as an Immune-Related eRNA in Glioblastoma Multiforme.

Enhancer RNAs, a type of long non-coding RNAs (lncRNAs), play a critical role in the occurrence and development of glioma. RNA-seq data from 161 glioblastoma multiforme (GBM) samples were acquired from The Cancer Genome Atlas database. Then, 70 eRNAs were identified as prognosis-related genes, which had significant relations with overall survival (log-rank test, p < 0.05). AC003092.1 was demonstrated as an immune-related eRNA by functional enrichment analysis. We divided samples into two groups based on AC003092.1 expression: AC003092.1 High (AC003092.1_H) and AC003092.1 Low (AC003092.1_L) and systematically analyzed the influence of AC003092.1 on the immune microenvironment by single-sample gene-set enrichment analysis and CIBERSORTx. We quantified AC003092.1 and TFPI2 levels in 11 high-grade gliomas, 5 low-grade gliomas, and 7 GBM cell lines. Our study indicates that AC003092.1 is related to glioma-immunosuppressive microenvironment, and these results offer innovative sights into GBM immune therapy.

Integrative analysis regarding the correlation between GAS2 family genes and human glioma prognosis.

BackgroundEmerging oncogenes were reportedly linked to the complicated subtypes and pathogenesis of clinical gliomas. Herein, we first comprehensively explored the potential correlation between growth‐arrest‐specific two family genes (GAS2, GAS2L1, GAS2L2, GAS2L3) and gliomas by bioinformatics analysis and cellular experiments.MethodsBased on the available datasets of TCGA (The Cancer Genome Atlas), CGGA (Chinese Glioma Genome Atlas), and Oncomine databases, we performed a series of analyses, such as gene expression, survival prognosis, DNA methylation, immune infiltration, and partner enrichment. We also utilized two glioma cell lines to conduct the colony formation and wound‐healing assay.Results GAS2L3 gene was highly expressed in glioma tissues compared to normal brain tissues (p < 0.05). We further observed the relationship between the high expressed GAS2L3 and poor clinical prognosis of brain low‐grade glioma (LGG) cases in our Cox proportional hazard model (hazard ratio [HR] = 0.1715, p < 0.001). Moreover, DNA hypomethylation status of GAS2L3 was correlated with the high expression of GAS2L3 in LGG tissues and the poor clinical prognosis of primary glioma cases (p < 0.05). We also found that the high expression of GAS2L3 was associated with the infiltration level of immune cells, especially the T cells (p < 0.0001). Functional enrichment analysis of GAS2L3‐correlated genes and interaction partners further indicated that GAS2L3 might take part in the occurrence of glioma by influencing a series of biological behaviors, such as cell division, cytoskeleton binding, and cell adhesion. Additionally, our cellular experiment data suggested that a highly expressed GAS2L3 gene contributes to the enhanced proliferation and migration of glioma cells.ConclusionThis study first analyzed the potential role of GAS2 family genes, especially GAS2L3, in the clinical prognosis and possible functional mechanisms of glioma, which gives a novel insight into the relationship between GAS2L3 and LGG.

IDH1 gene mutation activates Smad signaling molecules to regulate the expression levels of cell cycle and biological rhythm genes in human glioma U87‑MG cells.

Isocitrate dehydrogenase1 (IDH1) mutation is the most important genetic change in glioma. The most common IDH1 mutation results in the amino acid substitution of arginine 132 (Arg/R132), which is located at the active site of the enzyme. IDH1 Arg132His (R132H) mutation can reduce the proliferative rate of glioma cells. Numerous diseases follow circadian rhythms, and there is growing evidence that circadian disruption may be a risk factor for cancer in humans. Dysregulation of the circadian clock serves an important role in the development of malignant tumors, including glioma. Brain-Muscle Arnt-Like protein 1 (BMAL1) and Circadian Locomotor Output Cycles Kaput (CLOCK) are the main biological rhythm genes. The present study aimed to further study whether there is an association between IDH1 R132H mutation and biological rhythm in glioma, and whether this affects the occurrence of glioma. The Cancer Genome Atlas (TCGA) database was used to detect the expression levels of the biological rhythm genes BMAL1 and CLOCK in various types of tumor. Additionally, U87-MG cells were infected with wild-type and mutant IDH1 lentiviruses. Colony formation experiments were used to detect cell proliferation in each group, cell cycle distribution was detected by flow cytometry and western blotting was used to detect the expression levels of wild-type and mutant IDH1, cyclins, biological rhythm genes and Smad signaling pathway-associated genes in U87-MG cells. TCGA database results suggested that BMAL1 and CLOCK were abnormally expressed in glioma. Cells were successfully infected with wild-type and mutant IDH1 lentiviruses. Colony formation assay revealed decreased cell proliferation in the IDH1 R132H mutant group. The cell cycle distribution detected by flow cytometry indicated that IDH1 gene mutation increased the G1 phase ratio and decreased the S phase ratio in U87-MG cells. The western blotting results demonstrated that IDH1 R132H mutation decreased the expression levels of the S phase-associated proteins Cyclin A and CDK2, and increased the expression levels of the G1 phase-associated proteins Cyclin D3 and CDK4, but did not significantly change the expression levels of the G2/M phase-associated protein Cyclin B1. The expression levels of the positive and negative rhythm regulation genes BMAL1, CLOCK, period (PER s (PER1, 2 and 3) and cryptochrom (CRY)s (CRY1 and 2) were significantly decreased, those of the Smad signaling pathway-associated genes Smad2, Smad3 and Smad2-3 were decreased, and those of phosphorylated (p)-Smad2, p-Smad3 and Smad4 were increased. Therefore, the present results suggested that the IDH1 R132H mutation may alter the cell cycle and biological rhythm genes in U87-MG cells through the TGF-β/Smad signaling pathway.