Regulators In Glioma Research Articles

Discovery of GJC1 as a prognostic biomarker in glioma cells: insights into its cell-cycle relationship and differential expression in non-neuronal cells.

Gliomas, originating from the most common non-neuronal cells in the brain (glial cells), are the most common brain tumors and are associated with high mortality and poor prognosis. Glioma cells exhibit a tendency to disrupt normal cell-cycle regulation, leading to abnormal proliferation and malignant growth. This study investigated the predictive potential of GJC1 in gliomas and explored its relationship with the cell cycle. Retrospective analysis of RNA-seq and single-cell sequencing data was conducted using the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) databases. The differential expression of GJC1 in gliomas with various pathological features and in different non-neuronal cell groups was analyzed. Functional data were examined using gene set variation analysis (GSVA). Furthermore, CellMiner was used to evaluate the relationship between GJC1 expression and predicted treatment response across these databases. GJC1 expression was enriched in high-grade gliomas and 1p/19q non-codeletion gliomas. GJC1 enrichment was observed in classical and mesenchymal subtypes within the TCGA glioma subtype group. In single-cell subgroup analysis, GJC1 expression was higher in glioma tissues compared to other non-neuronal cells. Additionally, the TCGA classical subtype of glioma cells exhibited more GJC1 expression than the other subgroups. GJC1 emerged as an independent prognostic factor for overall survival in glioma. GSVA unveiled potential mechanisms by which GJC1 may impact cell-cycle regulation in glioma. Finally, a significant correlation was observed between GJC1 expression and the sensitivity of multiple anti-cancer drugs. These findings confirmed GJC1 as a novel biomarker and provided insights into the differential gene expression in non-neuronal cells and the impact of the cell cycle on gliomas. Consequently, GJC1 may be used to predict glioma prognosis and has potential therapeutic value.

Integrative analysis of genomic and epigenomic regulation reveals miRNA mediated tumor heterogeneity and immune evasion in lower grade glioma

The expression dysregulation of microRNAs (miRNA) has been widely reported during cancer development, however, the underling mechanism remains largely unanswered. In the present work, we performed a systematic integrative study for genome-wide DNA methylation, copy number variation and miRNA expression data to identify mechanisms underlying miRNA dysregulation in lower grade glioma. We identify 719 miRNAs whose expression was associated with alterations of copy number variation or promoter methylation. Integrative multi-omics analysis revealed four subtypes with differing prognoses. These glioma subtypes exhibited distinct immune-related characteristics as well as clinical and genetic features. By construction of a miRNA regulatory network, we identified candidate miRNAs associated with immune evasion and response to immunotherapy. Finally, eight prognosis related miRNAs were validated to promote cell migration, invasion and proliferation through in vitro experiments. Our study reveals the crosstalk among DNA methylation, copy number variation and miRNA expression for immune regulation in glioma, and could have important implications for patient stratification and development of biomarkers for immunotherapy approaches.

MAPK-activated protein kinase 2 is associated with poor prognosis of glioma patients and immune inhibition in glioma.

An effective therapeutic method to noticeably improve the prognosis of glioma patients has not been developed thus far. MAPK-activated protein kinase 2 (MAPKAPK2) is a serine/threonine kinase, which is involved in tumorigenesis, tumor growth, metastasis, and the inflammatory process. The clinical significance and molecular function of MAPKAPK2 in glioma remain unclear. MAPKAPK2 expression in human glioma tissues was detected by immunohistochemistry and analyzed from the transcriptome sequencing data in TCGA and CGGA. Prognostic nomogram was constructed to predict the survival risk of individual patients. GO and KEGG enrichment analyses were performed to analyze the function and pathways MAPKAPK2 involved. Single-cell RNA sequencing data was used to analyze the cell types in which MAPKAPK2 was enriched. Flow cytometry was used for cell cycle and apoptosis detection. The ability of cell proliferation and migration was analyzed by CCK8 and cell migration assay, respectively. Correlation analyses were performed to analyze the relationship of MAPKAPK2 with immune infiltration, immune regulators, chemokine, and chemokine receptors. MAPKAPK2 was not only aberrantly upregulated in glioma tissues but also correlated with poor clinical characteristics. Moreover, MAPKAPK2 was prevalent in isocitrate dehydrogenase (IDH) wild-type and 1p/19q non-codeletion glioma cohorts and predicted poor prognosis of glioma patients. MAPKAPK2 may be involved in cell proliferation, cell migration, DNA damage repair, and immune regulation in glioma. MAPKAPK2 was enriched in microglia/macrophages and malignant tumor cells. Further investigation into cellular function revealed that inhibiting MAPKAPK2 suppressed the proliferation and migration of glioblastoma multiforme (GBM) cells in vitro. The inhibition of MAPKAPK2 significantly induced the G1 cell cycle arrest and cell apoptosis of GBM cells. Consistent with the enriched function of MAPKAPK2 in immune regulation, MAPKAPK2 was correlated with immune cell infiltration in glioma tissues. Mechanistically, a series of immune regulators, immunomodulatory chemokine, and chemokine receptors were positively correlated with MAPKAPK2 expression. Our findings provide evidence of the clinical relevance of MAPKAPK2 in prognosis evaluation of glioma patients and highlight the underlying significance of MAPKAPK2 in glioma therapy.

Epigenetic and transcriptional activation of the secretory kinase FAM20C as an oncogene in glioma

Gliomas are the most prevalent and aggressive malignancies of the nervous system. Previous bioinformatic studies have revealed the crucial role of the secretory pathway kinase FAM20C in the prediction of glioma invasion and malignancy. However, little is known about the pathogenesis of FAM20C in the regulation of glioma. Here, we construct the full-length transcriptome atlas in paired gliomas and observe that 22 genes are upregulated by full-length transcriptome and differential APA analysis. Analysis of ATAC-seq data reveals that both FAM20C and NPTN are the hub genes with chromatin openness and differential expression. Further, in vitro and in vivo studies suggest that FAM20C stimulates the proliferation and metastasis of glioma cells. Meanwhile, NPTN, a novel cancer suppressor gene, counteracts the function of FAM20C by inhibiting both the proliferation and migration of glioma. The blockade of FAM20C by neutralizing antibodies results in the regression of xenograft tumors. Moreover, MAX, BRD4, MYC, and REST are found to be the potential trans-active factors for the regulation of FAM20C. Taken together, our results uncover the oncogenic role of FAM20C in glioma and shed new light on the treatment of glioma by abolishing FAM20C.

ADAMTS8 inhibits glioma development in vitro and in vivo.

In recent years, novel RNAs have been revealed to be regulators in glioma. ADAMTS8 has been reported to be reduced in brain tumours. In this study, we aimed to explore the role of ADAMTS8 in glioma. Online bioinformatic tools, Gepia and Chinese Glioma Genome Atlas database (CGGA) were used to analyse the differential expression of ADAMTS8, overall survival and disease-free survival rates and the correlations between ADAMTS8 and matrix metallopeptidases (MMP2 and MMP9) in glioma. RT-qPCR and western blot experiments were performed to measure the mRNA and protein expression. ADAMTS8 expression was regulated in cells through transfection. Thereafter, the effect of ADAMTS8 on cells was investigated through the cell viability, apoptosis and transwell experiments. The epithelial-mesenchymal transition (EMT)-related proteins and also MMP2 and MMP9 were examined. The subcutaneous tumour model was established to validate the suppressive role of ADAMTS8 in tumour growth. ADAMTS8 expression was reduced in glioma tissues and cells. Higher expression of ADAMTS8 was correlated with higher survival rates. ADAMTS8 was correlated with MMP2 and MMP9 in glioma tissues. In glioma cells, overexpression of ADAMTS8 could inhibit the viability, invasion, migration and EMT, and MMP2 and MMP9, but promote the apoptosis of cells. The upregulation of ADAMTS8 could inhibit the tumour growth in vivo. ADAMTS8 was inhibited in glioma and the higher expression of ADAMTS8 might be related to better prognosis among glioma patients. Overexpression of ADAMTS8 inhibited the development of glioma in vitro and in vivo.

Selected Articles from This Issue

Currently, there is no approved targeted therapy option for treatment naïve patients with AML harboring a FLT3 mutation ineligible for intensive therapy. Konopleva and colleagues investigated the efficacy of venetoclax plus azacitidine in an FLT3-mutated AML population and reported that the remission rates and OS among patients with or without FLT3 mutation were similar, suggesting that venetoclax and azacitidine maybe be used for treatment naïve AML patients who are ineligible for intensive chemotherapy regimens irrespective of FLT3 mutations. They also observed higher remission rates among patients exhibiting both FLT3-ITD and TKD mutations; however, the impact on OS warrants further investigation.Approximately 20% of patients with AML have IDH mutations. Preliminary data suggests they have better responses to venetoclax-based regimens. Pollyea and colleagues investigated the efficacy of venetoclax plus azacitidine in patients harboring IDH1/2 mutations. The responses and OS among these patients were superior compared to azacitidine alone. Furthermore, patients with IDH2 mutations had better outcomes than patients with IDH1 mutations. Finally, cytogenetic risk was not prognostic of OS in patients with IDH1/2 mutations treated with venetoclax plus azacitidine, while it was in IDH1/2 wild-type patients. This suggests that IDH status can overcome the prognostic significance of cytogenetics in some circumstances.Damage to the major salivary glands is a leading permanent side effect of radiation therapy for head and neck cancers, and no adequate treatment exists. Preclinical studies indicate that mesenchymal stem/stromal cell therapy may restore radiation-induced salivary gland damage. Duch Lynggaard and colleagues conducted a first-in-human investigator-initiated, randomized, placebo-controlled phase I/II trial to investigate the long-term safety of intraglandular injections of autologous adipose tissue-derived mesenchymal stem/stromal cells (ASCs) into the submandibular glands of patients previously treated for HPV+ oropharyngeal squamous cell carcinoma. This study demonstrates that autologous ASC therapy is safe and that it significantly reduced xerostomia related symptoms.Immunotherapeutic strategies hold great promise for malignant brain tumors, yet the determinants of an effective anti-tumor cytotoxic T-cell response are unclear. To explore what factors may be important, Kumar and colleagues performed multiomic profiling of a MAPK-activated glioma subtype with a robust CD8+ T cell and microglia/macrophage response. Increased CXCL14 secretion from tumor cells promoted CD8+ T cell chemotaxis, recruited brain tumor-infiltrating CD8+ T cells in vivo, and prolonged overall survival in a cytotoxic T cell-dependent manner. Together, these findings elucidate a novel mechanism of immune regulation in glioma.

RNA m1A Methyltransferase TRMT6 Predicts Poorer Prognosis and Promotes Malignant Behavior in Glioma.

Background: Glioma is the most prevalent central nervous system tumor in humans, and its prognosis remains unsatisfactory due to a lack of effective therapeutic targets. The ectopic expression of N1-methyladenosine (m1A) regulators is a key participant in tumorigenesis and progression. However, the m1A regulator expression status, prognostic value, and relationship with tumor clinical features in glioma remain unclear.Methods: Public datasets were used to analyze the mRNA and protein expression levels of m1A regulators. Kaplan–Meier and Cox regression analyses were performed to confirm the prognostic value of m1A regulators in glioma. Cellular experiments were conducted to verify the effect of TRMT6 on cell function. A comprehensive bioinformatics analysis was conducted to identify the potential molecular mechanisms regulated by TEMT6 in glioma.Results: We found that the dysregulation of m1A regulators was closely associated with tumorigenesis and progression in glioma. Furthermore, TRMT6 might be a powerful and independent biomarker for prognosis in glioma. Our study showed that inhibition of TRMT6 suppressed the proliferation, migration, and invasion of glioma cells. Mechanistically, TRMT6 may be involved in glioma progression by regulating cell cycle, PI3K-AKT, TGF-beta, MTORC1, NOTCH, and MYC pathways.Conclusions: Variation in m1A regulators was closely associated with malignant progression in glioma. Silencing TRMT6 suppressed the cell proliferation, migration, and invasion in glioma. m1A regulators, especially TRMT6, might play an essential role in the malignant progression of glioma.

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.

HOX gene regulation in glioma stem cells, mediators of resistance in breast cancer, and paradoxical therapeutic interventions

Therapy resistance remains a major challenge during the treatment of patients with advanced cancer. Due to the complex nature of the cellular and molecular mechanisms underlying therapy resistance, research efforts to tackle this challenge have focused on diverse aspects: from cancer stem cell (CSC) biology, therapy resistance-specific signatures to the development of new combinatorial therapeutic approaches. Among other articles, the August issue of Molecular Oncology includes several studies that directly or indirectly explore therapy resistance in patients with advanced cancer. In some cancers, therapeutic resistance has been linked to the presence of CSCs. In glioma, for example, glioma stem cells (GSCs) represent a tumor cell subpopulation underlying tumor relapse. Understanding the molecular mechanisms behind GSC gene expression may give new insights on tumorigenesis and tumor relapse. In their recent study, Le Boiteux et al. [[1]] analyzed six patient-derived GSC lines, as well as 70 primary adult diffuse glioma samples to map the mechanisms leading to deregulation of the HOX gene clusters, which have been previously implicated in the oncogenic potential of GSCs. The authors identified widespread reactivation of HOX genes in adult IDH wild-type (IDHwt) diffuse glioma samples and GSCs. HOX gene deregulation was associated with self- and cross-regulatory interactions between HOX transcription factors, but not with genomic rearrangements. Integrative analysis of high-throughput DNA methylation analysis, ChIPseq, and RNAseq data demonstrated that the absence of hypermethylation on canonical and alternative bivalent CpG islands in promoters, as well as loss of the H3K27me3 epigenetic mark, underlies aberrant gene expression of HOX clusters in IDHwt gliomas. Besides providing a comprehensive epigenetic analysis of HOX gene regulation in glioma, the study by Le Boiteux et al. highlights the complexity of HOX gene expression via alternative promoters in cancer. In a different setting, Mohammad Sultan and colleagues employed an in vivo genome-wide shRNA screen to identify potential mediators or biomarkers of paclitaxel resistance in patients with advanced breast cancer [[2]]. The transcriptional repressor BCL6 was identified among the top paclitaxel resistance hits, and BCL6 overexpression was detected in tumors of chemotherapy-resistant patients. To further test the role of BCL6 in paclitaxel resistance, the authors performed BCL6 knockdown and BCL6 inhibitor experiments both in vitro and in vivo, in a mouse model of triple-negative breast cancer. BCL6 targeting in preclinical models enhanced the efficacy of paclitaxel treatment. Thus, BCL6 may serve as a biomarker for drug resistance and may potentially be targeted for the treatment of patients with breast cancer that have developed paclitaxel resistance. In addition to chemotherapy, targeted therapies designed to block mitogenic signaling pathways are often used for the treatment of patients with cancer. However, drug resistance to these therapeutic agents represents a major challenge for the treatment of advanced cancer. In their perspective, Matheus Henrique Dias and Rene Bernards explore the prospects of a ‘paradoxical intervention’ strategy for the treatment of therapy-resistant cancers [[3]]. Such a strategy would involve overactivation, rather than inhibition, of mitotic signaling in cancer cells. In their view, such an approach would result in an overload of the stress response pathways and disruption of cancer cell homeostasis and viability. The authors review related data from several independent experimental models, discuss future perspectives, and explore the potential drawbacks of such a paradoxical intervention strategy for the treatment of patients with cancer.

MiR-451 suppresses EMT and metastasis in glioma cells

ABSTRACT The metastasis of tumor cells is a challenge for the clinical treatment of glioma. Epithelial-mesenchymal transition (EMT) contributes to glioma cell invasiveness. Our previous study confirmed that the expression of miRNA-451, which inhibits the PI3K/Akt signaling pathway by directly targeting CAB39 and plays a repressive role in glioma, is downregulated in glioma. However, the specific mechanism of miRNA-451 regulation in glioma is unclear. In this study, we investigated whether miRNA-451 blocks the processes of EMT and metastasis in glioma cells in vivo and in vitro. By targeting CAB39, miRNA-451 likely triggers the PI3K/Akt/Snail signaling pathway to reduce glioma proliferation, invasion, migration and EMT. We used Western blotting experiments to demonstrate that overexpression of miRNA-451 significantly reduced p-AKT(Ser473), N-cadherin, Vimentin, Twist, Snail and Cyclin D1 expression and increased E-cadherin expression. We demonstrated that overexpression of miR-451 suppressed glioma cell proliferation, invasion, migration and EMT by MTT and colony formation assays, Transwell assays, wound healing assays and animal experiments. Taken together, these results suggest that miRNA-451 can reduce EMT and metastasis in glioma cells through the suppression of the PI3K/Akt/Snail signaling pathway by targeting CAB39 in vitro and in vivo. miR-451 may be a new target for glioma treatment.

Systematic and Multi-Omics Prognostic Analysis of Lysine Acetylation Regulators in Glioma.

Lysine acetylation modification, which has key roles in cellular homeostasis as well as cancer malignancy, is dynamically regulated by lysine acetylation regulators (LARs). In our study, we found that most of 33 evaluated LARs were differentially expressed among 1,125 gliomas grouped by different clinicopathological characteristics. Consensus clustering was applied to 33 LARs, resulting in three glioma subtypes (LA1, 2, and 3). The LA3 subgroup was associated with the poorest clinical outcome, higher WHO grade, fewer isocitrate dehydrogenase mutations, and lower frequency of 1p/19q codeletion. Furthermore, gene set enrichment analysis indicated that eight tumor hallmarks were highly enriched in the LA3 subgroup. These results suggested that LARs are significantly related to glioma malignancy. We then designed a LAR-signature based on 14 overall survival (overall survival)-related LARs, and showed that the LAR-signature possesses strong and independent prognostic value for glioma patients in both training and validation datasets. Moreover, by interrogating single nucleotide polymorphism and copy number variation (CNV) data in The Cancer Genome Atlas dataset, we found that higher score of our risk signature is correlated with the hypermutation status of gliomas and that HDAC1(1p) was one of the oncogenes lost in 1p/19q codeletion events, while SIRT2(19q) and EP300(22q) may act as tumor suppressors in gliomas with 19q or 22q deletions, respectively. In conclusion, LARs are critical for the malignant development of gliomas, and our results are useful for prognostic stratification and development of novel assessment strategies for the prognosis of glioma patients.

The emerging role of the MiR-1272-ADAM9-CDCP1 signaling pathway in the progression of glioma.

Glioma is a primary, malignant, and aggressive brain tumor in adults. To develop new therapeutic strategies for glioma, we must determine its underlying mechanisms. In the present study, we aimed to investigate the potential role of miR-1272-ADAM9-CDCP1 signaling in the progression of glioma. We found that ectopic expression of miR-1272 produced significant inhibitory effects on cell proliferation and migration and was associated with cell cycle G0/G1 arrest in A172 and SHG44 glioma cells. Using the luciferase reporter assay, we identified ADAM9 as a target of miR-1272. The expression of ADAM9 was markedly decreased or increased after overexpression or inhibition, respectively, of miR-1272 in glioma cells. Moreover, overexpression of ADAM9 reversed the inhibitory effects of miR-1272 on glioma cell progression. Furthermore, CDCP1 served as a potential downstream molecule of miR-1272/ADAM9 signaling in glioma and promoted the proliferation and migration of glioma. Results derived from clinical samples and online databases confirmed correlations between the expression of ADAM9 and CDCP1 and both the severity and prognosis of glioma. In conclusion, these results suggest that miR-1272 and CDCP1 may act as novel regulators in glioma. The miR-1272/ADAM9/CDCP1 pathway may serve as a potential candidate pathway for the prevention of glioma.

MutT Homolog1 has multifaceted role in glioma and is under the apparent orchestration by Hypoxia Inducible factor1 alpha

AimsThe study focused on the expression and role of a recent potential cancer therapeutic target protein, MutT Homolog1 (MTH1). MTH1 gets activated in an increased reactive oxygen species (ROS) environment and removes the oxidized nucleotides from the cell. The study aimed to check the role of MTH1 in DNA damage and apoptosis, migration and angiogenesis and also to examine its regulation in glioma. Main methodsThe experiments were carried out in human glioma tissue samples and brain tissues of epilepsy patients (non-tumor control). We used two human glioblastomas cell lines, U87MG and U251MG cells. In order to study the role of MTH1 in glioma and to analyze the relation of MTH1 with Hif1α, we have used MTH1 siRNA and Hif1α siRNA respectively. Key findingsWe found an increased expression of MTH1 in glioma tissues compared to the non-tumor brain tissues. Correlation analysis revealed that those samples showing reduced expression of MTH1 also had high levels of DNA damage and apoptotic markers, while diminished expression of angiogenesis regulators and levels of migration. MTH1 knockdown in vitro by siRNA in tumor cell lines corroborates the above observation. This justifies the emergence of MTH1 inhibitors as potential first-in-class drugs. Mechanistically, our observations suggest that Hif1α may modulate MTH1 expression. SignificanceWe found elevated MTH1 expression in glioma irrespective of their grades, while its inhibition affects multiple tumor progression pathways, and that targeting Hif1α could simulate the same.

<p>Long Noncoding RNA LINC00173 Promotes NUTF2 Expression Through Sponging miR-765 and Facilitates Tumorigenesis in Glioma</p>

BackgroundGlioma is one of the leading causes of cancer-related deaths. This study aimed to investigate the function and mechanism of long noncoding RNA (lncRNA) LINC00173 in the regulation of glioma progression.MethodsLINC00173 expression was measured using qRT-PCR. Survival rate was analyzed through Kaplan–Meier method. CCK8, colony formation and EdU assays were performed to measure cell proliferation while transwell was used to determine cell migration and invasion. Luciferase reporter assay was conducted to test RNA interaction.ResultsLINC00173 expression was elevated in glioma tissues and cells. LINC00173 high expression predicted poor prognosis. Loss of LINC00173 inhibited proliferation, migration and invasion. LINC00173 interacted with miR-765 to enhance NUTF2 expression. MiR-765 expression was negatively correlated with LINC00173 and NUTF2 in glioma tissues. NUTF2 level was increased in glioma tissues. NUTF2 overexpression rescued the potential of proliferation, migration and invasion in LINC00173-silenced cells.ConclusionOur research demonstrated that LINC00173 promotes glioma progression through targeting miR-765/NUTF2 axis.

Transcription factor PU.1 is involved in the progression of glioma.

Glioma is a severe disease of the central nervous system. Although previous studies have identified the important role of the immune response in association with tumor intervention, it is still unknown whether PU.1, a transcription factor known for its role in myeloid differentiation and immune responses, is involved in the progression of glioma. In the present study, we found a significant increase in SPI1, the gene that encodes PU.1, in samples from patients with glioma. Through genotype-phenotype association analysis several candidate factors that may mediate the role of PU.1 in glioma were identified. To further validate the association between PU.1 and glioma we found that the expression of BTK, a potential target of PU.1, was also upregulated in patients with glioma. We also demonstrated that various biological pathways could be involved in PU.1-associated glioma by analyzing these potential targets in the Reactome database. These results provide evidence that PU.1 could serve a role in the progress of glioma through its transcriptional targets in multiple signaling pathways. Therefore, in addition to its role in hematopoietic linage development and leukemia, PU.1 appears to be involved in the regulation of glioma and potentially in other malignant cancers.

Downregulation of miR-16 via URGCP pathway contributes to glioma growth

Experimental and clinical evidence points to a critical role of Upregulator of cell proliferation (URGCP/URG4) in controlling the progression of multiple tumors. However, the oncogenic role of URGCP in glioma still remains elusive. In this study we tried to investigate the oncogenic roles and molecular mechanisms of URGCP in glioma. We found that the levels of URGCP were upregulated in glioma, and that the high-levels of URGCP indicated a worse prognosis in glioma patients. URGCP and miR-16 are critical for glioma growth: silencing URGCP (shURGCP) inhibited glioma growth, while, the shURGCP-mediated proliferative inhibition could be recovered by antagonizing miR-16 (anta-miR-16) in vivo and in vitro. Mechanically, URGCP repressed miR-16 expression via activating NF-κB/c-myc pathway in glioma; Cyclins D1 and Cyclin E1 were identified as the direct targets of miR-16, thus, URGCP-mediated miR-16 downregulation accelerated cell proliferation by upregulating Cyclin D1 and Cyclin E1 expression. All these results suggested that URGCP accelerates glioma growth through the NF-κB/c-myc/miR-16/Cyclin D1/E1 pathway, and both URGCP and miR-16 function as a novel cell cycle regulators in glioma and could be considered as potential targets for glioma therapy.

Abstract LB-334: xCT promotes malignant phenotypes in EGFR-expressing glioma

Abstract Malignant glioma such as glioblastoma is a cancer still difficult to treat. System xc(-) is composed of xCT and CD98hc subunits and functions as a plasma membrane antiporter for the uptake of extracellular cystine in exchange for intracellular glutamate, which has been reported to be involved in malignant phenotypes of glioma cells. However, the underlying mechanism of xCT regulation in glioma is not elucidated. Here we show that the epidermal growth factor receptor (EGFR) interacts with xCT and thereby promotes its cell surface expression and function in human glioma cells. EGFR-expressing glioma cells manifested both enhanced antioxidant capacity as a result of increased cystine uptake as well as increased extracellular glutamate which promotes glioma matrix invasion. Imaging mass spectrometry also revealed that brain tumors formed in mice by human glioma cells stably overexpressing EGFR contained higher levels of reduced glutathione compared with those formed by parental cells. Targeted inhibition of xCT suppressed the EGFR-dependent enhancement of antioxidant capacity in glioma cells as well as tumor growth and invasiveness. Our findings propose that xCT is a promising therapeutic target in EGFR-overexpressing malignant glioma. Citation Format: Kenji Tsuchihashi, Shogo Okazaki, Momoko Yoshikawa, Ryo Seishima, Oltea Sampetrean, Nobuyuki Onishi, Hiroaki Wakimoto, Frank Furnari, Eishi Baba, Koichi Akashi, Hideyuki Saya, Osamu Nagano. xCT promotes malignant phenotypes in EGFR-expressing glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-334. doi:10.1158/1538-7445.AM2017-LB-334

Abstract 114: TG02 induces cell cycle arrest in glioblastoma

Abstract Dysregulated cell cycle contributes to the limitless replicative potential of cancer cells. The cyclin-dependent kinases (CDKs) and cyclins, the CDK-regulatory proteins are the key cell cycle machinery and can be targets for cancer therapy. TG02, a pyrimidine-based multi-kinase inhibitor has an anti-glioma effect which was demonstrated by our previous studies. An in vitro kinase spectrum assay of TG02 demonstrated inhibitory effects in several CDKs at the nanomolar level. To further investigate the molecular mechanisms of TG02-induced cell cycle regulation in glioma, a cell cycle analysis was performed by flow cytometry using the Click-It Edu Flow Cytometric Assay Kit in GSC923 and U251 cell lines, a human stem-like cell and patient derived cell line, respectively. Protein expression of CDKs and cyclins was tested by Western blotting. RNAseq analysis using Next Generation Sequencing was performed (only GSC923) and followed by a supervised hierarchical clustering analysis of cell cycle pathways that were derived from Qiangen’s Ingenuity Pathway Analysis (IPA). Our results showed that TG02 treatment results in G2/M-phase arrest in glioma cell lines. The protein expression of CDK1, CDK2, cyclin A2 and cyclinB1 are downregulated in both TG02 treated cell lines. Additionally, RNAseq analysis revealed downregulation of cyclins A2, B1 and B2 and significant irregulation in mRNA expression of G2/M checkpoint and spindle formation proteins, indicating G2 checkpoint and mitosis progression are also affected by TG02. Taken together, we demonstrated that TG02 induced cell cycle G2/M arrest through downregulating CDK and cyclin expression signaling in the preclinical models of glioblastoma. These findings strongly support the further investigation of TG02 as a potential therapy for malignant gliomas. <!–EndFragment–> Citation Format: Yu-Ting Su, Robert Chen, Hallie Lappin, Herui Wang, Dragan Maric, Orieta Celiku, Aiguo Li, Mark R. Gilbert, Jing Wu. TG02 induces cell cycle arrest in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 114. doi:10.1158/1538-7445.AM2017-114

MiR-200c Inhibits the Tumor Progression of Glioma via Targeting Moesin.

We attempt to demonstrate the regulatory role of miR-200c in glioma progression and its mechanisms behind. Here, we show that miR-200c expression was significantly reduced in the glioma tissues compared to paratumor tissues, especially in malignant glioma. Exogenous overexpression of miR-200c inhibited the proliferation and invasion of glioma cells. In addition, the in vivo mouse xenograft model showed that miR-200c inhibited glioma growth and liver metastasis, which is mainly regulated by targeting moesin (MSN). We demonstrated that the expression of MSN in glioma specimens were negatively correlated with miR-200c expression, and MSN overexpression rescued the phenotype about cell proliferation and invasion induced by miR-200c. Moreover, knockdown of MSN was able to mimic the effects induced by miR-200c in glioma cells. These results indicate that miR-200c plays an important role in the regulation of glioma through targeting MSN.

Cytotoxic CD4+ T cells are correlated with better prognosis in Han Chinese grade II and grade III glioma subjects and are suppressed by PD-1 signaling

Purpose: Malignant gliomas are the most common tumors in the central nervous system with a poor prognosis. Recently, CD4+ cytotoxic T cells (CTLs) are being increasingly recognized as possessing antitumor capacity. However, their presence, activity and regulation in glioma have not been investigated in detail. Methods: To examine this, 72 grade II and grade III Han Chinese glioma patients and 30 Han Chinese healthy controls were investigated. Results: We found that compared to healthy controls, glioma patients had significantly upregulated frequencies of circulating CD4+ CTLs, identified by the expression of granzyme A (GzmA), granzyme B (GzmB) and/or perforin. The stimulated CD4+ CTLs in grade II and grade III glioma patients also had less proliferative ability than those in healthy controls, a feature of suppression that progressed with tumor grade. The frequencies of GzmB-expressing circulating CD4+ CTLs were directly associated with prognosis. We hypothesized that the programed death 1 (PD-1)/PD-ligand 1 (L1) interaction possibly contributed to the suppression of CD4+ CTLs in grade II and grade III glioma, since an upregulation of PD-1 was observed on CD4+ CTLs in glioma compared to those in the healthy individuals. Blockade of the PD-1/PD-L1 interaction with neutralizing antibodies significantly increased the proliferation and granzyme or perforin production by CD4+ CTLs in grade II and grade III glioma patients. Conclusions: These data suggest that the CD4+ CTLs in grade II and grade III glioma patients contribute to antitumor immunity and could be suppressed by PD-1 signal transduction.