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Glioblastomas (GBMs) are the most aggressive types of central nervous system tumors. Although certain genomic alterations have been identified as prognostic biomarkers of GBMs, the histomorphological features that predict their prognosis remain elusive. In this study, following an integrative diagnosis of 227 GBMs based on the 2021 World Health Organization classification system, the cases were histologically fractionated by cellular variations and abundance to evaluate the relationship between cellular heterogeneity and prognosis in combination with O-6-methylguanine-DNA methyltransferase gene promoter methylation (mMGMTp) status. GBMs comprised four major cell types: astrocytic, pleomorphic, gemistocytic, and rhabdoid cells. t-distributed stochastic neighbor embedding analysis using the histological abundance of heterogeneous cell types identified two distinct groups with significantly different prognoses. In individual cell component analysis, the abundance of gemistocytes showed a significantly favorable prognosis but confounding to mMGMTp status. Conversely, the abundance of epithelioid cells was correlated with the unfavorable prognosis. Linear model analysis showed the favorable prognostic utility of quantifying gemistocytic and epithelioid cells, independent of mMGMTp. The evaluation of GBM cell histomorphological heterogeneity is more effective for prognosis prediction in combination with mMGMTp analysis, indicating that histomorphological analysis is a practical and useful prognostication tool in an integrative diagnosis of GBMs. [ABSTRACT FROM AUTHOR]

Introduction: The Cuban population is genetically diverse, and information on the prevalence of genetic variants is still limited. As complex admixture processes have occurred, we hypothesized that the frequency of pharmacogenetic variants and drug responses may vary within the country. The aims of the study were to describe the frequency distribution of 43 single-nucleotide variants (SNVs) from 25 genes of pharmacogenetic interest within the Cuba population and in relation to other populations, while taking into consideration some descriptive variables such as place of birth and skin color. Materials and Methods: SNVs were analyzed in 357 unrelated healthy Cuban volunteers. Genotype, allele frequencies, and ancestry proportions were determined, and the pairwise fixation index (FST) was evaluated. Results: Hardy-Weinberg equilibrium (HWE) deviations in six loci (rs11572103, rs2740574, rs776746, rs3025039, rs861539, and rs1762429) were identified. Minor allele frequencies (MAFs) ranged from 0.00 to 0.15 for variants in genes encoding xenobiotic metabolizing enzymes. They also ranged from 0.01 to 0.21 for variants in DNA repair, growth factors, methyltransferase, and methylbinding proteins, while they ranged from 0.04 to 0.27 for variants in the O-6-methylguanine-DNA methyltransferase enzyme. Moderate genetic divergence was observed upon comparison to Africans (FST = 0.071 and SD 0.079), with 19 markers exhibiting moderate-to-large genetic differentiation. The average European, African, and Amerindian ancestry proportions were 67.8%, 27.2%, and 5.3%, respectively. Ancestry proportions differed by skin color and birthplace for both African and European components, with the exception of the European component, which showed no significant difference between individuals from Western and Eastern regions. Meanwhile, the statistical significance varied in comparisons by skin color and birthplace within the Amerindian component. Low genetic divergence was observed across geographical regions. We identified 12 variants showing moderate-to-large differentiation between White/Black individuals. Conclusion: Altogether, our results may support national strategies for the introduction of pharmacogenetic tools in clinical practice, contributing to the development of precision medicine in Cuba. [ABSTRACT FROM AUTHOR]

Introduction: The methylation of the O6-Methylguanine-DNA Methyltransferase (MGMT) promoter is a valid biomarker for predicting response to therapy with alkylating agents and, independently, prognosis in IDH-wildtype(IDH-w) glioblastoma. We aim to study the impact of its methylation in overall survival of the unresectable IDH-w glioblastoma undergoing biopsy and systemic treatment. Methods: We collected six-year retrospective (2017–2023) data at a quaternary neurosurgery center for patients undergoing biopsy as the only surgical procedure for an unresectable IDH wildtype glioblastoma. Data was collected from patient records including neuro-oncology multidisciplinary team meeting (MDT) documentation. Patients were grouped into categories according to different types of treatment received after biopsy (no treatment, chemotherapy (CT), radiotherapy (RT), chemoradiotherapy (CRT), chemoradiotherapy with adjuvant temozolomide (CRT with adjuvant TMZ), EORTC-NCIC protocol followed by second line treatment) and according to methylation status (unmethylated (< 5%), borderline methylated (5–15%) and strongly methylated (> 15%)). Survival analysis was performed. Results: 166 glioblastoma IDH wildtype patients were included in the study with mean age of 62.5 years (M: F = 1.5: 1). 70 (49.3%) patients had unmethylated MGMT status (< 5%), 29 (20.4%) patients had borderline methylated MGMT status (5–15%) and 43 (30.2%) patients had methylated MGMT status (> 15%). 36 (25.3%) patients did not receive any treatment post biopsy, 13 (9.1%) received CT only, 27 (19%) RT only, 12 (8.4%) CRT, 33 (23.2%) CRT with adjuvant TMZ, whereas 21 (14.7%) received EORTC-NCIC protocol along with second line treatment. In biopsy only group, there was no notable difference in survival outcomes among the different methylation statuses. For biopsy and any-other-form-of-treatment methylated groups showed a distinct trend of better survival compared to the borderline or unmethylated groups. Overall, methylated patients had better survival as compared to unmethylated or borderline groups. Conclusion: Methylated MGMT status are predictors for better overall survival in unresectable IDH wildtype glioblastoma patients undergoing biopsy and treatment regardless of the treatment modality. [ABSTRACT FROM AUTHOR]

The mechanisms underlying stimuli-induced dynamic structural remodeling of RNAs for the maintenance of cellular physiological function and survival remain unclear. Here, we showed that in MGMT promoter–methylated glioblastoma (GBM), the RNA helicase DEAD-box helicase 46 (DDX46) is phosphorylated by temozolomide (TMZ)–activated checkpoint kinase 1 (CHK1), resulting in a dense-to-loose conformational change and an increase in DDX46 helicase activity. DDX46-mediated tertiary structural remodeling of LINC01956 exposes the binding motifs of LINC01956 to the 3′ untranslated region of O6-methylguanine DNA methyltransferase (MGMT). This accelerates recruitment of MGMT mRNA to the RNA export machinery and transportation of MGMT mRNA from the nucleus to the cytoplasm, leading to increased MGMT abundance and TMZ resistance. Using patient-derived xenograft (PDX) and tumor organoid models, we found that treatment with the CHK1 inhibitor SRA737abolishes TMZ-induced structural remodeling of LINC01956 and subsequent MGMT up-regulation, resensitizing TMZ-resistant MGMT promoter–methylated GBM to TMZ. In conclusion, these findings highlight a mechanism underlying temozolomide-induced RNA structural remodeling and may represent a potential therapeutic strategy for patients with TMZ-resistant MGMT promoter–methylated GBM. Editor's summary: Glioblastomas are usually treated with temozolomide (TMZ), but up-regulation of O6-methylguanine DNA methyltransferase (MGMT) leads to resistance. MGMT promoter–methylated glioblastomas show reduced MGMT expression and increased sensitivity to TMZ, although resistance can occur through unclear mechanisms. Here, Liao and colleagues showed that in resistant MGMT promoter–methylated glioblastoma, TMZ activates checkpoint kinase 1 (CHK1), which then activates an RNA helicase that alters the tertiary structure of the long noncoding RNA LINC01956. LINC01956 can then bind to MGMT, resulting in increased MGMT export from the nucleus and ultimately TMZ resistance. Administration of a CHK1 inhibitor prevents the structural remodeling of LINC01956, thereby blocking up-regulation of MGMT and restoring sensitivity to TMZ in vitro and in mouse models of disease, suggesting a potential treatment option to resensitize resistant MGMT promoter–methylated glioblastoma to TMZ. —Melissa L. Norton [ABSTRACT FROM AUTHOR]

O6‐methylguanine DNA methyltransferase (MGMT) removes alkyl adducts from the guanine O6 position (O6‐MG) and repairs DNA damage. High MGMT expression results in poor response to temozolomide (TMZ). However, the biological importance of MGMT and the mechanism underlying its high expression in pancreatic neuroendocrine tumors (PanNETs) remain elusive. Here, it is found that MGMT expression is highly elevated in PanNET tissues compared with paired normal tissues and negatively associated with progression‐free survival (PFS) time in patients with PanNETs. Knocking out MGMT inhibits cancer cell growth in vitro and in vivo. Ectopic MEN1 expression suppresses MGMT transcription in a manner that depends on β‐Catenin nuclear export and degradation. The Leucine 267 residue of MEN1 is crucial for regulating β‐Catenin‐MGMT axis activation and chemosensitivity to TMZ. Interference with β‐Catenin re‐sensitizes tumor cells to TMZ and significantly reduces the cytotoxic effects of high‐dose TMZ treatment, and MGMT overexpression counteracts the effects of β‐Catenin deficiency. This study reveals the biological importance of MGMT and a new mechanism by which MEN1 deficiency regulates its expression, thus providing a potential combinational strategy for treating patients with TMZ‐resistant PanNETs. [ABSTRACT FROM AUTHOR]

AbstractPurposeMaterial and methodsResultsConclusionsTo investigate the role of moderate doses of ionizing radiation-induced cellular senescence in mouse lung tissue and whole-body inflammation levels.Forty-two C57BL/6J mice were randomly divided into the control group, the 1, 3, and 7 days after 2 Gy irradiation group, and the 1, 3, and 7 days after 4 Gy irradiation group, with six mice in each group. The histopathology, cellular senescence, oxidative-antioxidant, DNA damage repair, and inflammation-related indicators of irradiated mice were examined.Compared with the control group, the histopathological scores, the positive area of senescence-associated-β-galactosidase (SA-β-Gal) staining, and the mRNA levels of senescence-related genes in the lung tissues in all dose groups increased on 1, 3, and 7 days after irradiation. In peripheral blood, erythrocytes, leukocytes, platelets, hemoglobin, 8-hydroxydeoxyguanosine (8-OHdG), C-reactive protein, and other indicators showed a different trend in all dose groups. The levels of malondialdehyde(MDA), superoxide dismutase (SOD), glutathione (GSH), and 8-OHdG in the lung tissue showed different trends after 2 Gy and 4 Gy irradiation. The 8-Oxoguanine DNA glycosylase 1 (hOGG1) and O-6-methylguanine-DNA methyltransferase (MGMT) mRNA levels showed a trend of increasing and then decreasing. The levels of whole-body inflammation were significantly correlated with the levels of indicators related to cellular senescence and damage repair in the lung tissue of mice.The moderate doses of ionizing radiation induce oxidative stress, and DNA damage and increase DNA repair gene expression in mouse lung tissue. The lung tissue cellular senescence correlates with the level of whole-body inflammation. [ABSTRACT FROM AUTHOR]

Cells regularly repair numerous mutations. However, the effect of CRISPR/Cas9-induced dsDNA breaks on the repair processes of naturally occurring genome-wide mutations is unclear. In this study, we used TSCE5 cells with the heterozygous thymidine kinase genotype (TK+/−) to examine these effects. We strategically inserted the target sites for guide RNA (gRNA)/Cas9 and I-SceI into the functional allele and designed the experiment such that deletions of > 81 bp or base substitutions within exon five disrupted the TK gene, resulting in a TK−/− genotype. TSCE5 cells in the resting state exhibited 16 genome-wide mutations that affected cellular functions. After gRNA/Cas9 editing, these cells produced 859 mutations, including 67 high-impact variants that severely affected cellular functions under standard culture conditions. Mutation profile analysis indicated a significant accumulation of C to A substitutions, underscoring the widespread induction of characteristic mutations by gRNA/Cas9. In contrast, gRNA/Cas9-edited cells under conditions of S∼G2/M arrest and cyclin-dependent kinase 1 inhibition showed only five mutations. Transcriptomic analysis revealed the downregulation of DNA replication genes and upregulation of alternative DNA repair genes, such as zinc finger protein 384 (ZNF384) and dual specificity phosphatase, under S∼G2/M conditions. Additionally, activation of nucleotide and base excision repair gene, including O-6-methylguanine-DNA methyltransferase and xeroderma pigmentosum complementation group C, was observed. This study highlights the profound impact of CRISPR/Cas9 editing on genome-wide mutation processes and underscores the emergence of novel DNA repair pathways. Finally, our findings provide significant insights into the maintenance of genome integrity during genome editing. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the methodological quality and diagnostic accuracy of MRI-based radiomic studies predicting O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in gliomas. Methods: PubMed Medline, EMBASE, and Web of Science were searched to identify MRI-based radiomic studies on MGMT methylation in gliomas published until December 31, 2022. Three raters evaluated the study methodological quality with Radiomics Quality Score (RQS, 16 components) and Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis Or Diagnosis (TRIPOD, 22 items) scales. Risk of bias and applicability concerns were assessed with QUADAS-2 tool. A meta-analysis was performed to estimate the pooled area under the curve (AUC) and to assess inter-study heterogeneity. Results: We included 26 studies, published from 2016. The median RQS total score was 8 out of 36 (22%, range 8–44%). Thirteen studies performed external validation. All studies reported AUC or accuracy, but only 4 (15%) performed calibration and decision curve analysis. No studies performed phantom analysis, cost-effectiveness analysis, and prospective validation. The overall TRIPOD adherence score was between 50% and 70% in 16 studies and below 50% in 10 studies. The pooled AUC was 0.78 (95% CI, 0.73–0.83, I2 = 94.1%) with a high inter-study heterogeneity. Studies with external validation and including only WHO-grade IV gliomas had significantly lower AUC values (0.65; 95% CI, 0.57–0.73, p < 0.01). Conclusions: Study RQS and adherence to TRIPOD guidelines was generally low. Radiomic prediction of MGMT methylation status showed great heterogeneity of results and lower performances in grade IV gliomas, which hinders its current implementation in clinical practice. Clinical relevance statement: MGMT promoter methylation status appears to be variably correlated with MRI radiomic features; radiomic models are not sufficiently robust to be integrated into clinical practice to accurately predict MGMT promoter methylation status in patients with glioma before surgery. Key Points: • Adherence to the indications of TRIPOD guidelines was generally low, as was RQS total score. • MGMT promoter methylation status prediction with MRI radiomic features provided heterogeneous diagnostic accuracy results across studies. • Studies that included grade IV glioma only and performed external validation had significantly lower diagnostic accuracy than others. [ABSTRACT FROM AUTHOR]

Introduction: Glioblastoma, which affects a large number of patients every year and has an average overall lifespan of around 14.6 months following diagnosis stands out as the most lethal primary invasive brain tumor. Currently, surgery, radiation, and chemotherapy with temozolomide (TMZ) are the three major clinical treatment approaches. However, the ability to treat patients effectively is usually limited by TMZ resistance. Naringin, a bioflavonoid with anti-cancer, antioxidant, metal-chelating, and lipid-lowering effects, has emerged as a promising therapeutic option. Methods: To explore the targets and pathways of naringin and TMZ in glioblastoma network pharmacology, cell line-based ELISA, flow cytometry, immunocytochemistry, western blotting, and LC-HRMS based metabolomics study were used. Results: The findings through the network pharmacology suggested that the key targets of naringin in the chemosensitization of glioblastoma would be Poly [ADP-ribose] polymerase 1 (PARP-1), O-6-Methylguanine-DNA Methyltransferase (MGMT), and caspases. The functional enrichment analysis revealed that these targets were significantly enriched in important pathways such as p53 signaling, apoptosis, and DNA sensing. Further, the results of the in-vitro study in U87-MG and T98-G glioblastoma cells demonstrated that TMZ and naringin together significantly reduced the percentage of viability and inhibited the DNA repair enzymes PARP-1 and MGMT, and PI3K/AKT which led to chemosensitization and, in turn, induced apoptosis, which was indicated by increased p53, caspase-3 expression and decreased Bcl2 expression. Additionally, a metabolomics study in T98-G glioblastoma cells using liquid chromatography high-resolution mass spectrometry (LC-HRMS) revealed downregulation of C8-Carnitine (-2.79), L-Hexanoylcarnitine (-4.46), DLCarnitine (-2.46), Acetyl-L-carnitine (-3.12), Adenine (-1.3), Choline (-2.07), Propionylcarnitine (-1.69), Creatine (-1.33), Adenosine (-0.84), Spermine (-1.42), and upregulation of Palmitic Acid (+1.03) and Sphingosine (+0.89) in the naringin and TMZ treatment groups. Discussion: In conclusion, it can be said that naringin in combination with TMZ chemosensitized TMZ antiglioma response and induced apoptosis in tumor cells. [ABSTRACT FROM AUTHOR]

This document provides a summary of a research study that explores the relationship between IDH mutation, MGMT-promoter methylation, and PRMT5 gene expression in grade 4 astrocytoma. The study found that there is a significant relationship between MGMT-promoter methylation and IDH mutation in these tumors. It also suggests that using a PRMT5 inhibitor may be beneficial in tumor regression. The document also includes a list of references related to glioblastoma, providing valuable information for researchers and individuals interested in studying this type of brain cancer. [Extracted from the article]

AbstractBackgroundScope and approachKey findings and conclusionsCyanidin-3-O-glucoside (C3G), is an anthocyanin mainly found in berries, and can also be produced by microorganisms. It has been traditionally used as a natural coloring agent for decades. Recently, it has been investigated for its high antioxidant activity and anti-cancer attributes. C3G has low bioavailability and is sensitive to oxidation and gastric pH; therefore, it is encapsulated in nanoliposomes to enhance its bio-availability, targeted delivery- and efficacy against chronic disease.In this review, the role of C3G nanoliposomes against major chronic diseases has been discussed. The focus was on research findings and the mechanism of action to affect the proliferation of cancer, neuro disease and cardiovascular problems. It also discussed the formulation of nanoliposomes, their role in nutraceutical delivery and enhancement in C3G bioavailability.Data suggested that nanoliposomes safeguard C3G, enhance bioavailability, and ensure safe, adequate and targeted delivery. It can reduce the impact of cancer and inflammation by inhibiting the ß-catenin/O6-methylguanine-DNA methyltransferase (MGMT) pathway and upregulating miR-214-5p. Formation of C3G nanoliposomes significantly enhances the nutraceutical efficacy of C3G against major chronic disease therefore, C3G nanoliposomes might be a future-based nutraceutical to treat major chronic diseases, including cancer, neuro problems and CVD, but challenges remain in finding correct dose and techniques to maximize its efficacy. [ABSTRACT FROM AUTHOR]

Background: High-grade gliomas (HGGs) have a rapid relapse and short survival. Studies have identified many clinical characteristics and biomarkers associated with progression-free survival (PFS) and over-survival (OS). However, there has not yet a comprehensive study on survival after the first progression (SAP). Methods: From CGGA and TCGA, 319 and 308 HGGs were confirmed as the first progression. The data on clinical characteristics and biomarkers were analyzed in accordance with OS, PFS, and SAP. Results: Analysis of 319 patients from CGGA, significant predictors of improved OS/PFS/SAP were WHO grade, MGMT promoter methylation, and Ki-67 expression in univariate analysis. Further multivariate analysis showed MGMT promoter methylation and Ki-67 expression were independent predictors. However, an analysis of 308 patients from TCGA found MGMT promoter methylation is the only prognostic marker. A longer SAP was observed in patients with methylated MGMT promoter after standard chemoradiotherapy. In our data, HGGs could be divided into low, intermediate, and high-risk groups for SAP by MGMT methylation and Ki-67 expression. Conclusions: Patients with MGMT promoter methylation have a prolonger SAP after standard chemoradiotherapy. HGGs could be divided into low, intermediate, and high-risk groups for SAP according to MGMT status and Ki-67 expression. [ABSTRACT FROM AUTHOR]

Cancer chemotherapy is advancing as we understand how cellular mechanisms and drugs interact, particularly involving the enzyme MGMT, which repairs DNA damage that can cause cancer. This review examines MGMT's role in DNA repair, its impact on chemotherapy, and its complex interaction with radiation therapy. MGMT activity can both protect against mutations and cause drug resistance. Modulating MGMT could improve treatment efficacy and tailoring therapy to MGMT status may enhance patient outcomes. Understanding MGMT is crucial for developing precise cancer treatments and advancing patient care. [ABSTRACT FROM AUTHOR]

O6-methylguanine-DNA methyltransferase (MGMT) has been demonstrated to be an important prognostic and predictive marker in glioblastoma (GBM). To establish a reliable radiomics model based on MRI data to predict the MGMT promoter methylation status of GBM. A total of 183 patients with glioblastoma were included in this retrospective study. The visually accessible Rembrandt images (VASARI) features were extracted for each patient, and a total of 14676 multi-region features were extracted from enhanced, necrotic, "non-enhanced, and edematous" areas on their multiparametric MRI. Twelve individual radiomics models were constructed based on the radiomics features from different subregions and different sequences. Four single-sequence models, three single-region models and the combined radiomics model combining all individual models were constructed. Finally, the predictive performance of adding clinical factors and VASARI characteristics was evaluated. The ComRad model combining all individual radiomics models exhibited the best performance in test set 1 and test set 2, with the area under the receiver operating characteristic curve (AUC) of 0.839 (0.709–0.963) and 0.739 (0.581–0.897), respectively. The results indicated that the radiomics model combining multi-region and multi-parametric MRI features has exhibited promising performance in predicting MGMT methylation status in GBM. The Modeling scheme that combining all individual radiomics models showed best performance among all constructed moels. [ABSTRACT FROM AUTHOR]

Background/Aim: Previous studies suggested preoperative platelet-to-lymphocyte ratio (PLR) and neutrophilto-lymphocyte ratio (NLR) to be predictive factors in patients with glioblastoma multiforme (GBM). This study investigated the prognostic role of PLR and NLR prior to or at the beginning of radiotherapy. Patients and Methods: In 80 patients with GBM receiving conventionally fractionated radiotherapy plus concurrent temozolomide following resection or biopsy, 12 factors including PLR and NLR were retrospectively evaluated regarding progression-free survival (PFS) and overall survival (OS). Results: On multivariable analyses, PLR ≤150, Karnofsky performance score (KPS) 90-100, and O6-methylguanine-DNA methyltransferase promoter methylation were significantly associated with improved PFS. Single lesion, KPS 90-100, and adjuvant chemotherapy were significantly associated with OS; PLR ≤150 showed a trend. NLR ≤3 showed a trend for associations with PFS and OS on univariable analyses. Conclusion: PLR prior to or at the beginning of radiotherapy was associated with treatment outcomes in patients irradiated for GBM and should be considered in future clinical trials. [ABSTRACT FROM AUTHOR]

Aims: The methylation status of the O6‐methylguanine‐DNA methyltransferase (MGMT) promoter region is essential in evaluating the prognosis and predicting the drug response in patients with glioblastoma. In this study, we evaluated the utility of using nanopore long‐read sequencing as a method for assessing methylation levels throughout the MGMT CpG‐island, compared its performance to established techniques and demonstrated its clinical applicability. Methods: We analysed 165 samples from CNS tumours, focusing on the MGMT CpG‐island using nanopore sequencing. Oxford Nanopore Technologies (ONT) MinION and PromethION flow cells were employed for single sample or barcoded assays, guided by a CRISPR/Cas9 protocol, adaptive sampling or as part of a whole genome sequencing assay. Methylation data obtained through nanopore sequencing were compared to results obtained via pyrosequencing and methylation bead arrays. Hierarchical clustering was applied to nanopore sequencing data for patient stratification. Results: Nanopore sequencing displayed a strong correlation (R2 = 0.91) with pyrosequencing results for the four CpGs of MGMT analysed by both methods. The MGMT‐STP27 algorithm's classification was effectively reproduced using nanopore data. Unsupervised hierarchical clustering revealed distinct patterns in methylated and unmethylated samples, providing comparable survival prediction capabilities. Nanopore sequencing yielded high‐confidence results in a rapid timeframe, typically within hours of sequencing, and extended the analysis to all 98 CpGs of the MGMT CpG‐island. Conclusions: This study presents nanopore sequencing as a valid and efficient method for determining MGMT promotor methylation status. It offers a comprehensive view of the MGMT promoter methylation landscape, which enables the identification of potentially clinically relevant subgroups of patients. Further exploration of the clinical implications of patient stratification using nanopore sequencing of MGMT is warranted. [ABSTRACT FROM AUTHOR]

Background: Primary malignant brain tumours are more than one-third of all brain tumours and despite the molecular investigation to identify cancer driver mutations, the current therapeutic options available are challenging due to high intratumour heterogeneity. In addition, an immunosuppressive and inflammatory tumour microenvironment strengthens cancer progression. Therefore, we defined an immune and inflammatory profiling of meningioma and glial tumours to elucidate the role of the immune infiltration in these cancer types. Methods: Using tissue microarrays of 158 brain tumour samples, we assessed CD3, CD4, CD8, CD20, CD138, Granzyme B (GzmB), 5-Lipoxygenase (5-LOX), Programmed Death-Ligand 1 (PD-L1), O-6-Methylguanine-DNA Methyltransferase (MGMT) and Transglutaminase 2 (TG2) expression by immunohistochemistry (IHC). IHC results were correlated using a Spearman correlation matrix. Transcript expression, correlation, and overall survival (OS) analyses were evaluated using public datasets available on GEPIA2 in Glioblastoma (GBM) and Lower Grade Glioma (LGG) cohorts. Results: Seven out of ten markers showed a significantly different IHC expression in at least one of the evaluated cohorts whereas CD3, CD4 and 5-LOX were differentially expressed between GBMs and astrocytomas. Correlation matrix analysis revealed that 5-LOX and GzmB expression were associated in both meningiomas and GBMs, whereas 5-LOX expression was significantly and positively correlated to TG2 in both meningioma and astrocytoma cohorts. These findings were confirmed with the correlation analysis of TCGA-GBM and LGG datasets. Profiling of mRNA levels indicated a significant increase in CD3 (CD3D, CD3E), and CD138 (SDC1) expression in GBM compared to control tissues. CD4 and 5-LOX (ALOX5) mRNA levels were significantly more expressed in tumour samples than in normal tissues in both GBM and LGG. In GBM cohort, GzmB (GZMB), SDC1 and MGMT gene expression predicted a poor overall survival (OS). Moreover, in LGG cohort, an increased expression of CD3 (CD3D, CD3E, CD3G), CD8 (CD8A), GZMB, CD20 (MS4A1), SDC1, PD-L1, ALOX5, and TG2 (TGM2) genes was associated with worse OS. Conclusions: Our data have revealed that there is a positive and significant correlation between the expression of 5-LOX and GzmB, both at RNA and protein level. Further evaluation is needed to understand the interplay of 5-LOX and immune infiltration in glioma progression. [ABSTRACT FROM AUTHOR]

Glioblastoma (GB) is a devastating tumor of the central nervous system characterized by a poor prognosis. One of the best-established predictive biomarker in IDH-wildtype GB is O6-methylguanine-DNA methyltransferase (MGMT) methylation (mMGMT), which is associated with improved treatment response and survival. However, current efforts to monitor GB patients through mMGMT detection have proven unsuccessful. Small extracellular vesicles (sEVs) hold potential as a key element that could revolutionize clinical practice by offering new possibilities for liquid biopsy. This study aimed to determine the utility of sEV-based liquid biopsy as a predictive biomarker and disease monitoring tool in patients with IDH-wildtype GB. Our findings show consistent results with tissue-based analysis, achieving a remarkable sensitivity of 85.7% for detecting mMGMT in liquid biopsy, the highest reported to date. Moreover, we suggested that liquid biopsy assessment of sEV-DNA could be a powerful tool for monitoring disease progression in IDH-wildtype GB patients. This study highlights the critical significance of overcoming molecular underdetection, which can lead to missed treatment opportunities and misdiagnoses, possibly resulting in ineffective therapies. The outcomes of our research significantly contribute to the field of sEV-DNA-based liquid biopsy, providing valuable insights into tumor tissue heterogeneity and establishing it as a promising tool for detecting GB biomarkers. These results have substantial implications for advancing predictive and therapeutic approaches in the context of GB and warrant further exploration and validation in clinical settings. [ABSTRACT FROM AUTHOR]

Gliomas are the most common primary tumors of the central nervous system, with glioblastoma multiforme (GBM) having the highest incidence, and their therapeutic efficacy depends primarily on the extent of surgical resection and the efficacy of postoperative chemotherapy. The role of the intracranial blood–brain barrier and the occurrence of the drug‐resistant gene O6‐methylguanine‐DNA methyltransferase have greatly limited the efficacy of chemotherapeutic agents in patients with GBM and made it difficult to achieve the expected clinical response. In recent years, the rapid development of nanotechnology has brought new hope for the treatment of tumors. Nanoparticles (NPs) have shown great potential in tumor therapy due to their unique properties such as light, heat, electromagnetic effects, and passive targeting. Furthermore, NPs can effectively load chemotherapeutic drugs, significantly reduce the side effects of chemotherapeutic drugs, and improve chemotherapeutic efficacy, showing great potential in the chemotherapy of glioma. In this article, we reviewed the mechanisms of glioma drug resistance, the physicochemical properties of NPs, and recent advances in NPs in glioma chemotherapy resistance. We aimed to provide new perspectives on the clinical treatment of glioma. [ABSTRACT FROM AUTHOR]

Using radiomics to predict O6-methylguanine-DNA methyltransferase promoter methylation status in patients with newly diagnosed glioblastoma and compare the performances of different MRI sequences. Preoperative MRI scans from 215 patients were included in this retrospective study. After image preprocessing and feature extraction, two kinds of machine-learning models were established and compared for their performances. One kind was established using all MRI sequences (T1-weighted image, T2-weighted image, contrast enhancement, fluid-attenuated inversion recovery, DWI high, DWI low and apparent diffusion coefficient), and the other kind was based on single MRI sequence as listed above. For the machine-learning model based on all sequences, a total of seven radiomic features were selected with the Maximum Relevance and Minimum Redundancy algorithm. The predictive accuracy was 0.993 and 0.750 in the training and validation sets, respectively, and the area under curves were 1.000 and 0.754 in the two sets, respectively. For the machine-learning model based on single sequence, the numbers of selected features were 8, 10, 10, 13, 9, 7 and 6 for T1-weighted image, T2-weighted image, contrast enhancement, fluid-attenuated inversion recovery, DWI high, DWI low and apparent diffusion coefficient, respectively, with predictive accuracies of 0.797–1.000 and 0.583–0.694 in the training and validation sets, respectively, and the area under curves of 0.874–1.000 and 0.538–0.697 in the two sets, respectively. Specifically, T1-weighted image-based model performed best, while contrast enhancement-based model performed worst in the independent validation set. The machine-learning models based on seven different single MRI sequences performed differently in predicting O6-methylguanine-DNA methyltransferase status in glioblastoma, while the machine-learning model based on the combination of all sequences performed best. [ABSTRACT FROM AUTHOR]

The integration of multiple data sources is becoming increasingly important in the field of medical imaging for the purpose of improving predictions. In this study, we investigated the use of a unique combination of imaging and genomic data to predict the methylation status of the O6-methylguanine-DNA methyltransferase (MGMT). Utilizing a stacking generalization approach, our model achieved promising results. The classification report from the stacking ensemble shows a precision of 0.82, recall of 0.81, and an F1-score of 0.80. These findings demonstrate the potential of integrating diverse data sources in medical imaging to enhance predictive capabilities, specifically in the context of MGMT methylation status. Our study highlights the importance of ongoing research to refine and optimize the integration of multiple data sources, ultimately leading to more accurate predictions and tailored treatment strategies. This research has the potential to significantly impact patient outcomes by facilitating personalized interventions based on precise predictions of MGMT methylation status. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is a fatal brain tumor with limited treatment options. O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status is the central molecular biomarker linked to both the response to temozolomide, the standard chemotherapy drug employed for GBM, and to patient survival. However, MGMT status is captured on tumor tissue which, given the difficulty in acquisition, limits the use of this molecular feature for treatment monitoring. MGMT protein expression levels may offer additional insights into the mechanistic understanding of MGMT but, currently, they correlate poorly to promoter methylation. The difficulty of acquiring tumor tissue for MGMT testing drives the need for non-invasive methods to predict MGMT status. Feature selection aims to identify the most informative features to build accurate and interpretable prediction models. This study explores the new application of a combined feature selection (i.e., LASSO and mRMR) and the rank-based weighting method (i.e., MGMT ProFWise) to non-invasively link MGMT promoter methylation status and serum protein expression in patients with GBM. Our method provides promising results, reducing dimensionality (by more than 95%) when employed on two large-scale proteomic datasets (7k SomaScan® panel and CPTAC) for all our analyses. The computational results indicate that the proposed approach provides 14 shared serum biomarkers that may be helpful for diagnostic, prognostic, and/or predictive operations for GBM-related processes, given further validation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate gene expression alterations associated with overall survival (OS) in glioblastoma (GBM). Using the Nanostring nCounter platform, we identified four genes (COL1A2, IGFBP3, NGFR, and WIF1) that achieved statistical significance when comparing GBM with non-neoplastic brain tissue. The four genes were included in a multivariate Cox Proportional Hazard model, along with age, extent of resection, and O6-methylguanine-DNA methyltransferase (MGMT) promotor methylation, to create a unique glioblastoma prognostic index (GPI). The GPI score inversely correlated with survival: patient with a high GPI had a median OS of 7.5 months (18-month OS = 9.7%) whereas patients with a low GPI had a median OS of 20.1 months (18-month OS = 54.5%; log rank p-value = 0.004). The GPI score was then validated in 188 GBM patients from The Cancer Genome Atlas (TCGA) from a national data base; similarly, patients with a high GPI had a median OS of 10.5 months (18-month OS = 12.4%) versus 16.9 months (18-month OS = 41.5%) for low GPI (log rank p-value = 0.0003). We conclude that this novel mRNA-based prognostic index could be useful in classifying GBM patients into risk groups and refine prognosis estimates to better inform treatment decisions or stratification into clinical trials. [ABSTRACT FROM AUTHOR]

Objective: To elucidate the relationship between USP19 and O(6)‐methylguanine‐DNA methyltransferase (MGMT) after temozolomide treatment in glioblastoma (GBM) patients with chemotherapy resistance. Methods: Screening the deubiquitinase pannel and identifying the deubiquitinase directly interacts with and deubiquitination MGMT. Deubiquitination assay to confirm USP19 deubiquitinates MGMT. The colony formation and tumor growth study in xenograft assess USP19 affects the GBM sensitive to TMZ was performed by T98G, LN18, U251, and U87 cell lines. Immunohistochemistry staining and survival analysis were performed to explore how USP19 is correlated to MGMT in GBM clinical management. Results: USP19 removes the ubiquitination of MGMT to facilitate the DNA methylation damage repair. Depletion of USP19 results in the glioblastoma cell sensitivity to temozolomide, which can be rescued by overexpressing MGMT. USP19 is overexpressed in glioblastoma patient samples, which positively correlates with the level of MGMT protein and poor prognosis in these patients. Conclusion: The regulation of MGMT ubiquitination by USP19 plays a critical role in DNA methylation damage repair and GBM patients' temozolomide chemotherapy response. [ABSTRACT FROM AUTHOR]

Purposes: To identify potent DNA methylation candidates that could predict response to temozolomide (TMZ) in glioblastomas (GBMs) that do not have glioma‐CpGs island methylator phenotype (G‐CIMP) but have an unmethylated promoter of O‐6‐methylguanine‐DNA methyltransferase (unMGMT). Methods: The discovery‐validation approach was planned incorporating a series of G‐CIMP−/unMGMT GBM cohorts with DNA methylation microarray data and clinical information, to construct multi‐CpG prediction models. Different bioinformatic and experimental analyses were performed for biological exploration. Results: By analyzing discovery sets with radiotherapy (RT) plus TMZ versus RT alone, we identified a panel of 64 TMZ efficacy‐related CpGs, from which a 10‐CpG risk signature was further constructed. Both the 64‐CpG panel and the 10‐CpG risk signature were validated showing significant correlations with overall survival of G‐CIMP−/unMGMT GBMs when treated with RT/TMZ, rather than RT alone. The 10‐CpG risk signature was further observed for aiding TMZ choice by distinguishing differential outcomes to RT/TMZ versus RT within each risk subgroup. Functional studies on GPR81, the gene harboring one of the 10 CpGs, indicated its distinct impacts on TMZ resistance in GBM cells, which may be dependent on the status of MGMT expression. Conclusions: The 64 TMZ efficacy‐related CpGs and in particular the 10‐CpG risk signature may serve as promising predictive biomarker candidates for guiding optimal usage of TMZ in G‐CIMP−/unMGMT GBMs. [ABSTRACT FROM AUTHOR]

Background: Impact of Isocitrate dehydrogenase1 (IDH1) and O6-methylguanine-DNA methyltransferase (MGMT) in glioblastoma (GBM) have been of great interest due to their implications in prediction of prognosis of several types of cancer. It was aimed to investigate the clinical role of IDH1 mutation and MGMT methylation pattern among GBM patients versus non-neuro-oncological diseases (NND) patients and their impact on survival criteria. Methods: Formalin-fixed paraffin-embedded (FFPE) tissue sections of 58 GBM and 20 non-neuro-oncological diseases patients were recruited and IDH1 mutation and MGMT methylation was detected using Cast-PCR technology and Methyl II quantitative PCR approach, respectively. Results were assessed with other clinicopathological criteria and survival patterns. Results: IDH1 mutation was detected among 15 GBM cases (15/58) and it was not reported among NND (P = 0.011). Receiver operating characteristic (ROC) curve was plotted to discriminate between MGMT methylation among studied groups. Patients with MGMT methylation ≥ 66% were reported as high methylation, which was recorded significantly in 51.7% and 100% of GBM cases and NND, respectively. Both showed significant difference with performance status, while MGMT methylation was significantly related with tumor size and tumor location. IDH1 mutation and MGMT methylation reported significant increase with GB patients revealed complete response to treatment. Survival pattern was better for IDH1 mutation and MGMT high methylation as compared to IDH1 wild type or MGMT low–moderate methylation, respectively, and favorable survival was detected when both were combined than using either of them alone. Conclusion: Detection of IDH1 mutation and MGMT methylation among GB patients could aid in prediction of their response to treatment and their survival patterns, and their combination is better than using any of them alone. [ABSTRACT FROM AUTHOR]

Background: Glioma is one of the most drug and radiation-resistant tumors. Gliomas suffer from inter- and intratumor heterogeneity which makes the outcome of similar treatment protocols vary from patient to patient. This article is aimed to overview the potential imaging markers for individual diagnosis, prognosis, and treatment response prediction in malignant glioma. Furthermore, the correlation between imaging findings and biological and clinical information of glioma patients is reviewed. Materials and Methods: The search strategy in this study is to select related studies from scientific websites such as PubMed, Scopus, Google Scholar, and Web of Science published until 2022. It comprised a combination of keywords such as Biomarkers, Diagnosis, Prognosis, Imaging techniques, and malignant glioma, according to Medical Subject Headings. Results: Some imaging parameters that are effective in glioma management include: ADC, FA, Ktrans, regional cerebral blood volume (rCBV), cerebral blood flow (CBF), ve, Cho/NAA and lactate/lipid ratios, intratumoral uptake of 18F-FET (for diagnostic application), RD, ADC, ve, vp, Ktrans, CBFT1, rCBV, tumor blood flow, Cho/ NAA, lactate/lipid, MI/Cho, uptakes of 18F-FET, 11C-MET, and 18F-FLT (for prognostic and predictive application). Cerebral blood volume and Ktrans are related to molecular markers such as vascular endothelial growth factor (VEGF). Preoperative ADCmin value of GBM tumors is associated with O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. 2-hydroxyglutarate metabolite and dynamic 18F-FDOPA positron emission tomography uptake are related to isocitrate dehydrogenase (IDH) mutations. Conclusion: Parameters including ADC, RD, FA, rCBV, Ktrans, vp, and uptake of 18F-FET are useful for diagnosis, prognosis, and treatment response prediction in glioma. A significant correlation between molecular markers such as VEGF, MGMT, and IDH mutations with some diffusion and perfusion imaging parameters has been identified. [ABSTRACT FROM AUTHOR]

Accurate brain tumor classification is crucial for enhancing the diagnosis, prognosis, and treatment of glioblastoma patients. We employed the ResNet101 deep learning method with transfer learning to analyze the 2021 Radiological Society of North America (RSNA) Brain Tumor challenge dataset. This dataset comprises four structural magnetic resonance imaging (MRI) sequences: fluid‐attenuated inversion‐recovery (FLAIR), T1‐weighted pre‐contrast (T1w), T1‐weighted post‐contrast (T1Gd), and T2‐weighted (T2). We assessed the model's performance using standard evaluation metrics. The highest performance to detect MGMT methylation status for patients suffering glioblastoma was an accuracy (85.48%), sensitivity (80.64%), specificity (90.32%). Whereas classification performance with no tumor was yielded with accuracy (85.48%), sensitivity (90.32%), specificity (80.64%). The radiomic features (74) computed with ensembled Bagged Tree and relief feature selection method (30/74) improved the validation accuracy of 84.3% and AUC of 0.9038 to detect. O6‐methylguanine‐DNA methyltransferase (MGMT) promoter methylation status in glioblastoma patients holds promise for optimizing treatment planning and prognosis. By understanding MGMT methylation status, clinicians can make informed decisions about treatment strategies, potentially leading to improved clinical outcomes. [ABSTRACT FROM AUTHOR]

Backgroud: Glioblastoma multiforme (GBM) is among the most aggressive cancers, with current treatments limited in efficacy. A significant hurdle in the treatment of GBM is the resistance to the chemotherapeutic agent temozolomide (TMZ). The methylation status of the MGMT promoter has been implicated as a critical biomarker of response to TMZ. Methods: To explore the mechanisms underlying resistance, we developed two TMZ‐resistant GBM cell lines through a gradual increase in TMZ exposure. Transcriptome sequencing of TMZ‐resistant cell lines revealed that alterations in histone post‐translational modifications might be instrumental in conferring TMZ resistance. Subsequently, multi‐omics analysis suggests a strong association between histone H3 lysine 9 acetylation (H3K9ac) levels and TMZ resistance. Results: We observed a significant correlation between the expression of H3K9ac and MGMT, particularly in the unmethylated MGMT promoter samples. More importantly, our findings suggest that H3K9ac may enhance MGMT transcription by facilitating the recruitment of the SP1 transcription factor to the MGMT transcription factor binding site. Additionally, by analyzing single‐cell transcriptomics data from matched primary and recurrent GBM tumors treated with TMZ, we modeled the molecular shifts occurring upon tumor recurrence. We also noted a reduction in tumor stem cell characteristics, accompanied by an increase in H3K9ac, SP1, and MGMT levels, underscoring the potential role of H3K9ac in tumor relapse following TMZ therapy. Conclusions: The increase in H3K9ac appears to enhance the recruitment of the transcription factor SP1 to its binding sites within the MGMT locus, consequently upregulating MGMT expression and driving TMZ resistance in GBM. [ABSTRACT FROM AUTHOR]

Background: Epidermal growth factor receptor (EGFR) is frequently activated in head and neck squamous cell carcinoma (HNSCC) and serves as a valuable target for therapy. Despite the availability of the EGFR inhibitors Cetuximab, Afatinib, and Allitinib, there are limited predictive markers for their response. Understanding molecular aberrations in HNSCC could facilitate the identification of new strategies for patient clinical and biological classification, offering novel therapeutic avenues. Methods: We assessed CCNA1, DCC, MGMT, CDKN2A/p16, and DAPK methylation status in HNSCC cell lines and their association with anti‐EGFR treatment response. Results: MGMT methylation status displayed high sensitivity and specificity in distinguishing sensitive and resistant HNSCC cell lines to Afatinib (AUC = 0.955) and Allitinib (AUC = 0.935). Moreover, DAPK methylation status predicted response to Allitinib with high accuracy (AUC = 0.852), indicating their putative predictive biomarker roles. Conclusion: These findings hold promise for the development of more personalized and effective treatment approaches for HNSCC patients. [ABSTRACT FROM AUTHOR]

Introduction: In 2021, the World Health Organization published a new classification system for central nervous system tumors. This study reclassified the adult diffuse glioma (ADG) into astrocytoma, oligodendroglioma, and glioblastoma (GBM) according to the new tumor classification. Methods: The association of TERT promoter (pTERT) mutation, MGMT methylation, and CD47/TIGIT expression with patient prognosis was investigated. Results: Immunohistochemical analysis showed that the expression levels of CD47 and TIGIT in tumor tissues were significantly higher than those in normal brain tissues. CD47 levels were higher in GBM and grade 4 astrocytoma tissues. TIGIT expression was also higher in patients with GBM. The high expressions of CD47, TIGIT, and CD47/TIGIT were positively correlated with MGMT unmethylation but not pTERT mutation. Moreover, MGMT unmethylation was associated with poor overall survival in astrocytoma. High CD47, TIGIT, and CD47/TIGIT levels were associated with significantly reduced survival in ADG and GBM. GBM, MGMT unmethylation, and high CD47 expression were independent prognostic factors for overall survival in ADG. Discussion: Collectively, these results showed that the MGMT unmethylation and high levels of CD47 and TIGIT are associated with a poor prognosis in ADG. Patients with high CD47 and TIGIT expression may benefit from anti-CD47 and TIGIT immunotherapy. [ABSTRACT FROM AUTHOR]

Introduction: The methylation status of oxygen 6-methylguanine-DNA methyltransferase (MGMT) is closely related to the treatment and prognosis of glioblastoma. However, there are currently some challenges in detecting the methylation status of MGMT promoters. The hematoxylin and eosin (H&E)- stained histopathological slides have always been the gold standard for tumor diagnosis. Methods: In this study, based on the TCGA database and H&E-stained Whole slide images (WSI) of Beijing Tiantan Hospital, we constructed a weakly supervised prediction model of MGMT promoter methylation status in glioblastoma by using two Transformer structure models. Results: The accuracy scores of this model in the TCGA dataset and our independent dataset were 0.79 (AUC= 0.86) and 0.76 (AUC= 0.83), respectively. Conclusion: The model demonstrates effective prediction of MGMT promoter methylation status in glioblastoma and exhibits some degree of generalization capability. At the same time, our study also shows that adding Patches automatic screening module to the computational pathology research framework of glioma can significantly improve the model effect. [ABSTRACT FROM AUTHOR]

The methylation status of the O6-methylguanine DNA methyltransferase (MGMT) promoter region is a critical predictor of response to alkylating agents in glioblastoma. However, current approaches to study the MGMT status focus on analyzing models with non-identical backgrounds. Here, we present an epigenetic editing approach using CRISPRoff to introduce site-specific CpG methylation in the MGMT promoter region of glioma cell lines. Sanger sequencing revealed successful introduction of methylation, effectively generating differently methylated glioma cell lines with an isogenic background. The introduced methylation resulted in reduced MGMT mRNA and protein levels. Furthermore, the cell lines with MGMT promoter region methylation exhibited increased sensitivity to temozolomide, consistent with the impact of methylation on treatment outcomes in patients with glioblastoma. This precise epigenome-editing approach provides valuable insights into the functional relevance of MGMT promoter regional methylation and its potential for prognostic and predictive assessments, as well as epigenetictargeted therapies. [ABSTRACT FROM AUTHOR]

Aims: Patients with Crohn's disease (CrD) have an elevated risk for the development of small bowel adenocarcinomas (SBAs). Actionable isocitrate dehydrogenase 1 (IDH1) mutations have been reported to be more frequent in CrD‐SBAs than in sporadic SBAs. The present study aimed to investigate the clinicopathological and immunophenotypical features, as well as methylation profiles, of IDH1‐mutated CrD‐SBAs. Methods and results: An international multicentre series of surgically resected CrD‐SBAs was tested for IDH1 mutation. Clinicopathological features, immunophenotypical marker expression and O6‐methylguanine‐DNA methyltransferase (MGMT) and long interspersed nuclear element‐1 (LINE‐1) methylation were compared between IDH1‐mutated and IDH1 wild‐type CrD‐SBAs. Ten (20%) of the 49 CrD‐SBAs examined harboured an IDH1 mutation and all the mutated cancers harboured the R132C variant. Compared to IDH1 wild‐type cases, IDH1‐mutated CrD‐SBAs showed significantly lower rates of cytokeratin 7 expression (P = 0.005) and higher rates of p53 overexpression (P = 0.012) and MGMT methylation (P = 0.012). All three dysplastic growths associated with IDH1‐mutated SBAs harboured the same IDH1 variant (R132C) of the corresponding invasive cancer, and all were of non‐conventional subtype (two serrated dysplastic lesions and one goblet cell‐deficient dysplasia). In particular, non‐conventional serrated dysplasia was significantly associated with IDH1‐mutated CrD‐SBAs (P = 0.029). No significant cancer‐specific survival difference between IDH1‐mutated CrD‐SBA patients and IDH1 wild‐type CrD‐SBA patients was found (hazard ratio = 0.55, 95% confidence interval = 0.16–1.89; P = 0.313). Conclusions: IDH1‐mutated CrD‐SBAs, which represent approximately one‐fifth of total cases, are characterised by distinctive immunophenotypical features and methylation profiles, with potential therapeutic implications. Moreover, IDH1‐mutated non‐conventional, serrated dysplasia is likely to represent a precursor lesion to such CrD‐SBAs. [ABSTRACT FROM AUTHOR]

The function of direct DNA damage repair protein, namely MGMT in MM, and the impact of MGMT on melphalan treatment remains unclear. We showed a significantly higher MGMT mRNA expression in CD138+ myeloma cells than in matched CD138‐nontumorigenic cells derived from newly diagnosed and relapsed/refractory MM patients using qPCR. However, using gene expression databases, a similar expression of MGMT was observed during disease progression. MGMT depletion by its specific inhibitor lomeguatrib reduced myeloma cell viability, impaired S phase entry and DNA repair, and increased DNA damage and apoptosis. Apoptosis and DNA damage were further elevated by combined treatment with lomeguatrib and melphalan in RPMI 8226 cells. This is the first study demonstrating MGMT inhibition enhances DNA damage‐induced apoptosis and melphalan cytotoxicity in MGMT‐proficient MM cells and suggesting using lomeguatrib might have clinical importance in treating MM and overcoming melphalan resistance in MGMT‐proficient patients. [ABSTRACT FROM AUTHOR]

Aim: Glioblastoma (GBM) has been reported to be the most common high‐grade primary malignant brain tumor in clinical practice and has a poor prognosis. O6‐methylguanine‐DNA methyltransferase (MGMT) promoter methylation has been related to prolonged overall survival (OS) in GBM patients after temozolomide treatment. Methods: Proteomics and metabolomics were combined to explore the dysregulated metabolites and possible protein expression alterations in white matter (control group), MGMT promoter unmethylated GBM (GBM group) or MGMT promoter methylation positive GBM (MGMT group). Results: In total, 2745 upregulated and 969 downregulated proteins were identified in the GBM group compared to the control group, and 131 upregulated and 299 downregulated proteins were identified in the MGMT group compared to the GBM group. Furthermore, 131 upregulated and 299 downregulated metabolites were identified in the GBM group compared to the control group, and 187 upregulated and 147 downregulated metabolites were identified in the MGMT group compared to the GBM group. The results showed that 94 upregulated and 19 downregulated proteins and 20 upregulated and 16 downregulated metabolites in the MGMT group were associated with DNA repair. KEGG pathway enrichment analysis illustrated that the dysregulated proteins and metabolites were involved in multiple metabolic pathways, including the synthesis and degradation of ketone bodies, amino sugar and nucleotide sugar metabolism. Moreover, integrated metabolomics and proteomics analysis was performed, and six key proteins were identified in the MGMT group and GBM group. Three key pathways were recognized as potential biomarkers for recognizing MGMT promoter unmethylated GBM and MGMT promoter methylation positive GBM from GBM patient samples, with areas under the curve of 0.7895, 0.7326 and 0.7026, respectively. Conclusion: This study provides novel mechanisms to understand methylation in GBM and identifies some biomarkers for the prognosis of two different GBM types, MGMT promoter unmethylated or methylated GBM, by using metabolomics and proteomics analyses. [ABSTRACT FROM AUTHOR]

Background: Attempts should be made to identify the molecule‑based biomarkers, which give indication about the progression of precancer and malignancy of the oral area. Aim: To evaluate the reliability of methylation of genes of saliva like P16, MGMT, and DAP‑K as biomarkers for diagnosis of oral squamous cell carcinoma. Methods and Materials: This study included 30 cases of histopathologically proven cases of oral squamous cell carcinoma. This study was conducted to detect demethylation of genes P16, MGMT, and DAP‑K in saliva in these patients. Approximately, 1 mL of saliva was collected from each individual. Bisulfite sequencing PCR (BSP) was done with bisulfite conversion‑specific primers produced by MethPrimer. The BSP compounds will be quantified on a one percent agarose gel. A fraction of the products obtained in BSP were then analyzed with the help of qMSP. Results: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of methylation of genes P16, MGMT, and DAP‑K as biomarkers of oral carcinoma were statistically significant. In our research, there were some very important useful findings regarding the possibility of the use of deoxyribonucleic acid methylation as a potential biomarker for the progression of premalignancy and malignancy of oral cavity, which need to be further followed up. Conclusion: Salivary biomarkers like P16, MGMT, and DAP‑K can be used in the diagnosis of oral squamous cell carcinoma. [ABSTRACT FROM AUTHOR]

Background: Glioblastoma (GBM) is a highly lethal brain tumor. The effectiveness of temozolomide (TMZ) treatment in GBM is linked to the methylation status of O6-methyl-guanine DNA methyltransferase (MGMT) promoter. Patients with unmethylated MGMT promoter have limited treatment options available. Consequently, there is a pressing need for alternative therapeutic strategies for such patients. Methods: Data, including transcriptomic and clinical information, as well as information on MGMT promoter methylation status in primary GBM, were obtained from The Cancer Genome Atlas (TCGA) (n=121) and Chinese Glioma Genome Atlas (CGGA) (n=83) datasets. Samples were categorized into high and low MGMT expression groups, MGMT-high (MGMT-H) and MGMT-low (MGMT-L) tumors. A comprehensive transcriptome analysis was conducted to explore the tumor-immune microenvironment. Furthermore, we integrated transcriptome data from 13 GBM patients operated at our institution with findings from tumor-infiltrating lymphocyte (TIL) cultures, specifically investigating their response to autologous tumors. Results: Gene signatures associated with various immune cells, including CD8 T cells, helper T cells, B cells, and macrophages, were noted in MGMT-H tumors. Pathway analysis confirmed the enrichment of immune cell-related pathways. Additionally, biological processes involved in the activation of monocytes and lymphocytes were observed in MGMT-H tumors. Furthermore, TIL culture experiments showed a greater presence of tumor-reactive T cells in MGMT-H tumors compared to MGMT-L tumors. These findings suggest that MGMT-H tumors has a potential for enhanced immune response against tumors mediated by CD8 T cells. Conclusion: Our study provides novel insights into the immune cell composition of MGMT-H tumors, which is characterized by the infiltration of type 1 helper T cells and activated B cells, and also the presence of tumor-reactive T cells evidenced by TIL culture. These findings contribute to a better understanding of the immune response in MGMT-H tumors, emphasizing their potential for immunotherapy. Further studies are warranted to investigate on the mechanisms of MGMT expression and antitumor immunity. [ABSTRACT FROM AUTHOR]

Gliomas continue to have a dismal prognosis. A myriad of genetic alterations has been described in this subset of tumors over the last decades. The integrative interpretation of the biomarker constellation for individual patients remains unclear. This study aims to evaluate the impact of some known genetic factors as prognostic biomarkers in grade 4 gliomas. Adult non-H3-altered grade 4 gliomas who underwent maximal safe resection accompanied by adjuvant therapy were successively enrolled since January 2019 till January 2021. Patient data were documented preoperatively and during the follow-up visits. The genetic profiling of the tumors included Isocitrate Dehydrogenase (IDH)-1 and IDH-2 mutation, MGMT promoter methylation rate, EGFR gene amplification and telomerase reverse transcriptase gene promoter (TERTp) mutation. Mean Overall survival (OS) and Progression-free survival (PFS) were 14.45 ± 5.13 months (3–24 months) and 10.66 ± 4.87 months respectively. TERTp-mutant group had a significantly lower OS (10.9 vs. 15.9) and PFS (6.9 vs. 12.3) than TERTp wildtype group. In the TERT-mutant group, those with concomitant IDH wildtype tumor had higher OS and PFS, comparable to those with both TERTp and IDH wildtype tumors. In multivariate analysis, IDH mutation and TERTp wildtype status were predictive of longer OS and PFS. While IDH and absence of TERTp mutation were associated with KPS > 80 across the follow-ups, their predictive values were inferior to preoperative KPS scores. TERTp mutation and IDH-wildtype status were associated with worse OS and PFS and lower follow-up KPS score in surgically resected gliomas, while MGMT and EGFR status did not have considerable prognostic value in this study. [ABSTRACT FROM AUTHOR]

Novel non-nucleoside inhibitors of MGMT (O6-methylguanine-DNA methyltransferase) have shown high efficacy and low level of cytotoxicity in human cancer cells HEp-2. But it is important to investigate the impact of new inhibitors in other human cancer cells, especially, those which have different levels of MGMT expression. This study was performed using two glioma cell lines: T98G with a high level of MGMT expression and U251MG with a methylated promoter in the MGMT gene. Methods. Western-blot analysis of the level of MGMT. The autophagy level and number of alive and dead cells were measured with fluorescence microscopy and fluorescence spectrophotometry after Monodansylcadaverine dying for autophagosomes and dying by Live-Dead Imaging Cell Kit respectively. Results. The new inhibitors significantly reduce MGMT level, but this effect could be observed only after 24-hour treatment. Longer treatment has a weaker inhibiting effect compared with standard inhibitor O6-benzylguanine. The combined treatment by the inhibitors and nitrosoguanidine induces a high autophagy level in T98G cells, whereas in U251MG cells a low level of autophagy was observed. The analyzed inhibitors do not elevate the level of dead cells in both cell lines. However, the combined treatment leads to a high death rate only in T98G cells. Conclusions. The analyzed compounds have inhibiting activity against MGMT in glioma cells. The inhibitors don't affect glioma cells' survival and autophagy level however make them more sensitive to an alkylating agent. [ABSTRACT FROM AUTHOR]

The O-6-methylguanine-DNA methyltransferase (MGMT) gene is a critical guardian of genomic integrity. MGMT methylation in diffuse gliomas serves as an important determinant of patients' prognostic outcomes, more specifically in glioblastomas (GBMs). In GBMs, the absence of MGMT methylation, known as MGMT promoter unmethylation, often translates into a more challenging clinical scenario, tending to present resistance to chemotherapy and a worse prognosis. A pyrosequencing (PSQ) technique was used to analyze MGMT methylation status at different cut-offs (5%, 9%, and 11%) in a sample of 78 patients diagnosed with IDH-wildtype grade 4 GBM. A retrospective analysis was provided to collect clinicopathological and prognostic data. A statistical analysis was used to establish an association between methylation status and treatment response (TR) and disease-specific survival (DSS). The patients with methylated MGMT status experienced progressive disease rates of 84.6%, 80%, and 78.4% at the respective cut-offs of 5%, 9%, and 11%. The number was considerably higher when considering unmethylated patients, as all patients (100%), regardless of the cut-off, presented progressive disease. Regarding disease-specific survival (DSS), the Hazard Ratio (HR) was HR = 0.74 (0.45–1.24; p = 0.251); HR = 0.82 (0.51–1.33; p = 0.425); and HR = 0.79 (0.49–1.29; p = 0.350), respectively. Our study concludes that there is an association between MGMT unmethylation and worse TR and DSS. The 9% cut-off demonstrated a greater potential for patient survival as a function of time, which may shed light on the future need for standardization of MGMT methylation positivity parameters in PSQ. [ABSTRACT FROM AUTHOR]

The methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter is a molecular marker associated with a better response to chemotherapy in patients with glioblastoma (GB). Standard pre-operative magnetic resonance imaging (MRI) analysis is not adequate to detect MGMT promoter methylation. This study aims to evaluate whether the radiomic features extracted from multiple tumor subregions using multiparametric MRI can predict MGMT promoter methylation status in GB patients. This retrospective single-institution study included a cohort of 277 GB patients whose 3D post-contrast T1-weighted images and 3D fluid-attenuated inversion recovery (FLAIR) images were acquired using two MRI scanners. Three separate regions of interest (ROIs) showing tumor enhancement, necrosis, and FLAIR hyperintensities were manually segmented for each patient. Two machine learning algorithms (support vector machine (SVM) and random forest) were built for MGMT promoter methylation prediction from a training cohort (196 patients) and tested on a separate validation cohort (81 patients), based on a set of automatically selected radiomic features, with and without demographic variables (i.e., patients' age and sex). In the training set, SVM based on the selected radiomic features of the three separate ROIs achieved the best performances, with an average of 83.0% (standard deviation: 5.7%) for accuracy and 0.894 (0.056) for the area under the curve (AUC) computed through cross-validation. In the test set, all classification performances dropped: the best was obtained by SVM based on the selected features extracted from the whole tumor lesion constructed by merging the three ROIs, with 64.2% (95% confidence interval: 52.8–74.6%) accuracy and 0.572 (0.439–0.705) for AUC. The performances did not change when the patients' age and sex were included with the radiomic features into the models. Our study confirms the presence of a subtle association between imaging characteristics and MGMT promoter methylation status. However, further verification of the strength of this association is needed, as the low diagnostic performance obtained in this validation cohort is not sufficiently robust to allow clinically meaningful predictions. [ABSTRACT FROM AUTHOR]

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Early detection of treatment response is important for the management of patients with malignant brain tumors such as glioblastoma to assure good quality of life in relation to therapeutic efficacy. To investigate whether parametric response mapping (PRM) with diffusion MRI may provide prognostic information at an early stage of standard therapy for glioblastoma. This prospective study included 31 patients newly diagnosed with glioblastoma WHO grade IV, planned for primary standard postoperative treatment with radiotherapy 60Gy/30 fractions with concomitant and adjuvant Temozolomide. MRI follow-up including diffusion and perfusion weighting was performed at 3 T at start of postoperative chemoradiotherapy, three weeks into treatment, and then regularly until twelve months postoperatively. Regional mean diffusivity (MD) changes were analyzed voxel-wise using the PRM method (MD-PRM). At eight and twelve months postoperatively, after completion of standard treatment, patients were classified using conventional MRI and clinical evaluation as either having stable disease (SD, including partial response) or progressive disease (PD). It was assessed whether MD-PRM differed between patients having SD versus PD and whether it predicted the risk of disease progression (progression-free survival, PFS) or death (overall survival, OS). A subgroup analysis was performed that compared MD-PRM between SD and PD in patients only undergoing diagnostic biopsy. MGMT-promotor methylation status (O6-methylguanine-DNA methyltransferase) was registered and analyzed with respect to PFS, OS and MD-PRM. Of the 31 patients analyzed: 21 were operated by resection and ten by diagnostic biopsy. At eight months, 19 patients had SD and twelve had PD. At twelve months, ten patients had SD and 20 had PD, out of which ten were deceased within twelve months and one was deceased without known tumor progression. Median PFS was nine months, and median OS was 17 months. Eleven patients had methylated MGMT-promotor, 16 were MGMT unmethylated, and four had unknown MGMT-status. MD-PRM did not significantly predict patients having SD versus PD neither at eight nor at twelve months. Patients with an above median MD-PRM reduction had a slightly longer PFS (P = 0.015) in Kaplan-Maier analysis, as well as a non-significantly longer OS (P = 0.099). In the subgroup of patients only undergoing biopsy, total MD-PRM change at three weeks was generally higher for patients with SD than for patients with PD at eight months, although no tests were performed. MGMT status strongly predicted both PFS and OS but not MD-PRM change. MD-PRM at three weeks was not demonstrated to be predictive of treatment response, disease progression, or survival. Preliminary results suggested a higher predictive value in non-resected patients, although this needs to be evaluated in future studies. • Diffusion parametric response maps (PRM) measure voxel-wise change during therapy. • Diffusion PRM was not predictive for response in resected glioblastoma WHO grade IV. • Diffusion PRM predicted treatment response in biopsied glioblastoma. • Diffusion PRM is not correlated to MGMT-status in glioblastoma. [ABSTRACT FROM AUTHOR]

The aim of our study was to investigate the potential of rutin, catechin, dehydrozingerone, naringenin, and quercetin, both alone and in combination with temozolomide, to inhibit the expression of O6-methylguanine-DNA methyltransferase (MGMT) in glioma cells. MGMT has been shown to be a major cause of temozolomide resistance in glioma. Our study used both in silico and in vitro methods to assess the inhibitory activity of these phytochemicals on MGMT, with the goal of identifying the most effective combination of compounds for reducing temozolomide resistance. After conducting an initial in silico screening of natural compounds against MGMT protein, five phytochemicals were chosen based on their high docking scores and favorable binding energies. From the molecular docking and simulation studies, we found that quercetin showed a good inhibitory effect of MGMT with its high binding affinity. C6 glioma cells showed increased cytotoxicity when treated with the temozolomide and quercetin combination. It was understood from the isobologram and combination index plot that the drug combination showed a synergistic effect at the lowest dose. Quercetin when combined with temozolomide significantly decreased the MGMT levels in C6 cells in comparison with the other drugs as estimated by ELISA. The percentage of apoptotic cells increased significantly in the temozolomide–quercetin group indicating the potency of quercetin in decreasing the resistance of temozolomide as confirmed by acridine orange/ethidium bromide staining. Our experiment hence suggests that temozolomide resistance can be reduced by combining the drug with quercetin which will serve as an effective therapeutic target for glioblastoma treatment. [ABSTRACT FROM AUTHOR]

Temozolomide (TMZ) is a conventional chemotherapeutic drug for glioma, however, its clinical application and efficacy is severely restricted by its drug resistance properties. O6-methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme, which can repair the DNA damage caused by TMZ. A large number of clinical data show that reducing the expression of MGMT can enhance the chemotherapeutic efficacy of TMZ. Therefore, in order to improve the resistance of glioma to TMZ, an angiopep-2 (A2) modified nanoprodrug of polytemozolomide (P(TMZ)n) that combines with MGMT siRNA (siMGMT) targeting MGMT was developed (A2/T/D/siMGMT). It not only increased the amount of TMZ within tumor lesion site, but also reduced MGMT expression in glioma. The in vitro experiments indicated that the A2/T/D/siMGMT effectively enhanced the cellular uptake of TMZ and siMGMT, and resulted in a significant cell apoptosis and cytotoxicity in the glioma cells. The in vivo experiments showed that glioma growth was inhibited and the survival time of animals were prolonged remarkably after A2/T/D/siMGMT was injected via tail vein. The results showed that the therapeutic effect of A2/T/D/siMGMT in the treatment of glioma was significantly improved. [ABSTRACT FROM AUTHOR]

Anesthetic drugs had been reported may impact the bio-behavior of the tumor. Propofol and sevoflurane are common anesthetics in the operation for glioblastoma (GBM). This study aims to establish a co-expression prognostic-related genes signature base on propofol and sevoflurane anesthesia to predict prognosis and immunotherapy response in GBM. GPM tissues with different anesthetics gene expression profiles (GSE179004) were obtained from the Gene Expression Omnibus (GEO) database. Core modules and central genes associated with propofol and sevoflurane anesthesia were identified by weighted gene coexpression network analysis (WGCNA) and establish a risk score prognostic model. Immune cell signature analysis in TCGA datasets was predicted via CIBERSORT. At last, serum methylation level of O6-methylguanine-DNA methyltransferase (MGMT) promoter was detected in GPM patient in different time during perioperative period. The burlywood1 group screened was significantly associated with sevoflurane-treated GBM tissue. 22 independent prognostic differential genes were construct a prognostic-related genes risk score in GBM, and showed good predictive ability. The risk score was strongly correlated with the age of the patients, but not with the sex of the patients. In addition, the differential responses to immunotherapy in high and low risk groups were analyzed, indicating that sevoflurane signature genes were consistent in the classification of gliomas. High-risk patients have high T-cell damage score and are less sensitive to immunotherapy. At last, serum methylation level of MGMT promoter was decreased in GBM patients during propofol and sevoflurane anesthesia. Propofol and sevoflurane anesthesia associated impact on the gene expression of GBM, included the methylation level of MGMT promoter. Propofol and sevoflurane anesthesia-based risk score prognostic model, which has good prognostic power and is an independent prognostic factor in GBM patients. Therefore, this model can be used as a new biomarker for judging the prognosis of GBM patients. Propofol and sevoflurane anesthesia-based risk score prognostic model has good prognostic power and is an independent prognostic factor in GBM patients. High Propofol and sevoflurane anesthesia-based risk score GBM patients have high T-cell damage scores and are less sensitive to immunotherapy. Serum methylation level of MGMT promoter decrease during propofol and sevoflurane anesthesia in GBM patients. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most aggressive primary brain tumor, exhibiting a high rate of recurrence and poor prognosis. Surgery and chemoradiation with temozolomide (TMZ) represent the standard of care, but, in most cases, the tumor develops resistance to further treatment and the patients succumb to disease. Therefore, there is a great need for the development of well-tolerated, effective drugs that specifically target chemoresistant gliomas. NEO214 was generated by covalently conjugating rolipram, a PDE4 (phosphodiesterase 4) inhibitor, to perillyl alcohol, a naturally occurring monoterpene related to limonene. Our previous studies in preclinical models showed that NEO214 harbors anticancer activity, is able to cross the blood-brain barrier (BBB), and is remarkably well tolerated. In the present study, we investigated its mechanism of action and discovered inhibition of macroautophagy/autophagy as a key component of its anticancer effect in glioblastoma cells. We show that NEO214 prevents autophagy-lysosome fusion, thereby blocking autophagic flux and triggering glioma cell death. This process involves activation of MTOR (mechanistic target of rapamycin kinase) activity, which leads to cytoplasmic accumulation of TFEB (transcription factor EB), a critical regulator of genes involved in the autophagy-lysosomal pathway, and consequently reduced expression of autophagy-lysosome genes. When combined with chloroquine and TMZ, the anticancer impact of NEO214 is further potentiated and unfolds against TMZ-resistant cells as well. Taken together, our findings characterize NEO214 as a novel autophagy inhibitor that could become useful for overcoming chemoresistance in glioblastoma. Abbreviations: ATG: autophagy related; BAFA1: bafilomycin A1; BBB: blood brain barrier; CQ: chloroquine; GBM: glioblastoma; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MGMT: O-6-methylguanine-DNA methyltransferase; MTOR: mechanistic target of rapamycin kinase; MTORC: MTOR complex; POH: perillyl alcohol; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TMZ: temozolomide [ABSTRACT FROM AUTHOR]