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12 result(s) for "Hana, Taijun"
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Region‐specific DNA hydroxymethylation along the malignant progression of IDH‐mutant gliomas
The majority of low‐grade isocitrate dehydrogenase‐mutant (IDH mt ) gliomas undergo malignant progression (MP), but their underlying mechanism remains unclear. IDH mt gliomas exhibit global DNA methylation, and our previous report suggested that MP could be partly attributed to passive demethylation caused by accelerated cell cycles. However, during MP, there is also active demethylation mediated by ten‐eleven translocation, such as DNA hydroxymethylation. Hydroxymethylation is reported to potentially contribute to gene expression regulation, but its role in MP remains under investigation. Therefore, we conducted a comprehensive analysis of hydroxymethylation during MP of IDH mt astrocytoma. Five primary/malignantly progressed IDH mt astrocytoma pairs were analyzed with oxidative bisulfite and the Infinium EPIC methylation array, detecting 5‐hydroxymethyl cytosine at over 850,000 locations for region‐specific hydroxymethylation assessment. Notably, we observed significant sharing of hydroxymethylated genomic regions during MP across the samples. Hydroxymethylated CpGs were enriched in open sea and intergenic regions ( p  < 0.001), and genes undergoing hydroxymethylation were significantly associated with cancer‐related signaling pathways. RNA sequencing data integration identified 91 genes with significant positive/negative hydroxymethylation‐expression correlations. Functional analysis suggested that positively correlated genes are involved in cell‐cycle promotion, while negatively correlated ones are associated with antineoplastic functions. Analyses of The Cancer Genome Atlas clinical data on glioma were in line with these findings. Motif‐enrichment analysis suggested the potential involvement of the transcription factor KLF4 in hydroxymethylation‐based gene regulation. Our findings shed light on the significance of region‐specific DNA hydroxymethylation in glioma MP and suggest its potential role in cancer‐related gene expression and IDH mt glioma malignancy.
Accurate Preoperative and Intraoperative Evaluation Reduces Surgical Costs and Patient Invasiveness in Ventriculoperitoneal Shunt Revision
The ventriculoperitoneal (VP) shunt is one of the most common surgical procedures in neurosurgery, frequently resulting in malfunctions. Shunt malfunctions, which can include mechanical failure, obstruction, infection, or disconnection, occur in a significant percentage of patients, often necessitating multiple revisions. These revisions can lead to increased healthcare costs due to additional surgeries or treatments. Therefore, addressing the economic impacts of these revisions is crucial. Our report presents a cost-effective approach to shunt revisions, demonstrated through a case study of an 82-year-old woman with hydrocephalus. Although initially treated with a VP shunt, she required a revision after six years due to shunt malfunction. Through comprehensive preoperative and intraoperative evaluations, including a shuntogram with iodine contrast and meticulous examination, we identified the cause of malfunction as a connective tissue sac blocking the peritoneal catheter. The surgery involved flushing the catheter lumen with saline to confirm the obstruction and careful removal of the obstructive tissue. This accurate diagnosis facilitated a minimally invasive revision, enabling the reuse of existing shunt components and avoiding the need for new devices, thus reducing costs and surgical invasiveness. Our study serves as a call to action for healthcare providers and surgeons to consider more cost-effective and patient-friendly approaches in managing VP shunt malfunctions, ultimately benefiting both the healthcare system and the patients it serves.
DNA demethylation is associated with malignant progression of lower-grade gliomas
To elucidate the mechanisms of malignant progression of lower-grade glioma, molecular profiling using methylation array, whole-exome sequencing, and RNA sequencing was performed for 122, 36 and 31 gliomas, respectively. This cohort included 24 matched pairs of initial lower-grade gliomas and recurrent tumors, most of which showed malignant progression. Nearly half of IDH-mutant glioblastomas that had progressed from lower-grade gliomas exhibited characteristic partial DNA demethylation in previously methylated genomic regions of their corresponding initial tumors, which had the glioma CpG island methylator phenotype (G-CIMP). In these glioblastomas, cell cycle-related genes, RB and PI3K-AKT pathway genes were frequently altered. Notably, late-replicating domain was significantly enriched in the demethylated regions that were mostly located in non-regulatory regions, suggesting that the loss of DNA methylation during malignant transformation may involve mainly passive demethylation due to a delay in maintenance of methylation during accelerated cell division. Nonetheless, a limited number of genes including IGF2BP3 , which potentially drives cell proliferation, were presumed to be upregulated due to demethylation of their promoter. Our data indicated that demethylation of the G-CIMP profile found in a subset of recurrent gliomas reflects accelerated cell divisions accompanied by malignant transformation. Oncogenic genes activated by such epigenetic change represent potential therapeutic targets.
Mining-Guided Machine Learning Analyses Revealed the Latest Trends in Neuro-Oncology
In conducting medical research, a system which can objectively predict the future trends of the given research field is awaited. This study aims to establish a novel and versatile algorithm that predicts the latest trends in neuro-oncology. Seventy-nine neuro-oncological research fields were selected with computational sorting methods such as text-mining analyses. Thirty journals that represent the recent trends in neuro-oncology were also selected. As a novel concept, the annual impact (AI) of each year was calculated for each journal and field (number of articles published in the journal × impact factor of the journal). The AI index (AII) for the year was defined as the sum of the AIs of the 30 journals. The AII trends of the 79 fields from 2008 to 2017 were subjected to machine learning predicting analyses. The accuracy of the predictions was validated using actual past data. With this algorithm, the latest trends in neuro-oncology were predicted. As a result, the linear prediction model achieved relatively good accuracy. The predicted hottest fields in recent neuro-oncology included some interesting emerging fields such as microenvironment and anti-mitosis. This algorithm may be an effective and versatile tool for prediction of future trends in a particular medical field.
A Case of Enigmatic Stroke Caused by Severe Systemic Sepsis: The Importance of Careful Assessment of Insidious Systemic Infection
Severe sepsis is a dreaded disease with high mortality, especially in the case of delayed detection. Early diagnosis and treatment initiation is critical for patient survival. However, the septic conditions might be masked by other clinical conditions such as stroke, which may result in a serious delay in diagnosis and treatment. We report a case of iliopsoas abscess that initially presented with cerebellar infarction and subarachnoid hemorrhage. Although severe neurological symptoms were prominent, some signs indicating systemic infection, such as “psoas position”, prompted us to investigate the existence of systemic infection. Consequently, severe sepsis with multiple infectious foci, such as iliopsoas abscess, purulent spondylitis, mitral valve valvulitis, and brain abscess, was revealed and was detected as the cause of stroke. The timely and accurate diagnosis of sepsis minimized the delay of the initiation of antibiotic treatment. Approximately five months of intensive care, including two heart valve surgeries, cured the patient, and she was discharged with no neurological deficit. This case demonstrates the importance of careful assessment of the insidious systemic infection as a covert cause of stroke.
835 Heterologous prime boost viral vector vaccination provides protection against intracranial syngeneic murine glioblastoma
BackgroundGlioblastomas are immunologically ‘cold’ tumors with sparse cytotoxic T-cell infiltration. Therefore, viral vector vaccines may be a promising approach to boost the induction of glioblastoma-targeted T cells. It has been previously shown that heterologous prime-boost vaccination with chimpanzee-derived adenovirus ChAdOx1 and modified vaccinia Ankara (MVA) vectors can induce a high magnitude of CD8+ T cells specific for cancer-associated antigens and have therapeutic effects against mouse models of cancer.1 Therefore, we aimed to evaluate whether treating mice with ChAdOx1 and MVA vaccines targeting model tumor antigens and endogenous antigens could be beneficial in the prophylactic and therapeutic settings against syngeneic, intracranial murine glioblastoma.MethodsMurine glioblastoma cell lines were developed to express model tumour antigens. In addition, endogenous tumor-associated antigens and neoantigens were identified in murine glioblastoma lines using our novel Mouse nEoanTigen pRedictOr (METRO) antigen discovery pipeline. We then created ChAdOx1 and MVA vectors expressing model tumor antigens or endogenous antigen candidates, and we confirmed their immunogenicity via intracellular cytokine staining of ex vivo stimulated peripheral blood mononuclear cells or splenocytes. In the prophylactic tumor setting, mice were vaccinated with ChAdOx1 and MVA vectors expressing endogenous antigens or a model tumor antigen, then challenged with syngeneic intracranial wild-type or model antigen expressing tumors, respectively. In the therapeutic setting, mice bearing intracranial tumors were treated with vaccines in combination with checkpoint inhibitors after confirming tumor formation.ResultsChAdOx1 and MVA heterologous prime-boost vaccination generated a high magnitude of antigen-specific CD8+ T cells against a model tumor antigen. Furthermore, we confirmed the immunogenicity of some of the antigens identified by the METRO pipeline. Prophylactic vaccination targeting a model tumor antigen significantly increased the survival time of mice bearing intracranial tumors engineered to express the same antigen. Ongoing studies are investigating the efficacy of this vaccination strategy in the therapeutic setting.ConclusionsOur heterologous prime-boost strategy generates a high magnitude of antigen-specific CD8+ T cells that provide protection against the development of orthotopic glioblastoma tumors in mice. It remains to be seen whether these vaccines can provide a therapeutic benefit to mice bearing intracranial tumors, and the effects of vaccination on the remodeling of the tumor microenvironment and tumor-draining lymph nodes are yet to be determined. Preclinical data generated using our vaccine and tumor models may provide proof-of-concept to move these vaccines into clinical trials to treat patients with glioblastoma.ReferenceMcAuliffe J, Chan HF, Noblecourt L, Ramirez-Valdez RA, Pereira-Almeida V, Zhou Y, Pollock E, Cappuccini F, Redchenko I, Hill AV, Leung CSK, Van den Eynde BJ. Heterologous prime-boost vaccination targeting MAGE-type antigens promotes tumor T-cell infiltration and improves checkpoint blockade therapy. J Immunother Cancer. 2021 Sep;9(9):e003218.Ethics ApprovalAll animal work was approved by either the University of Oxford Animal Care and Ethical Review Committee and experimental procedures were carried out in accordance with the terms of the UK Animals (Scientific Procedures) Act Project Licenses P0D369534 and PB050649E; or by the National Cancer Institute-Bethesda Animal Care and Use Committee and experimental procedures were carried out in accordance with the terms of Protocol NOB-024.
Publisher Correction: DNA demethylation is associated with malignant progression of lower-grade gliomas
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
Rapid intracranial pressure drop as a cause for posterior reversible encephalopathy syndrome: Two case reports
Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by reversible edematous lesions on radiological examinations as well as symptoms of altered consciousness and seizures. To date, the underlying mechanism remains largely unknown. Case Descriptions: Case 1 is a 72-year-old man with a history of hypertension presented with a subarachnoid hemorrhage. Fourteen days after the successful clipping of a ruptured aneurysm; he experienced inadvertent overdrainage via the intraventricular drain. Nine hours later, he started to have seizures followed by disturbances in consciousness. An emergency magnetic resonance imaging showed multiple high-intensity lesions in the frontal, temporal, parietal, and occipital lobes, basal ganglia, brainstem, and cerebellar hemispheres bilaterally, which are compatible with typical magnetic resonance findings in PRES patients. He was treated conservatively and recovered well. Case 2 is a 68-year-old woman with a mild history of hypertension and a ventriculo-peritoneal shunt for obstructive hydrocephalus, who underwent a cysto-peritoneal shunt placement because of an enlarging symptomatic arachnoid cyst. Immediately following surgery, she experienced disturbances in consciousness and developed status epilepticus. Radiological examinations revealed remarkable shrinkage of the arachnoid cyst and multiple edematous lesions, which led us to strongly suspect PRES. With conservative treatment, her symptoms and the radiological abnormalities disappeared. Conclusion: Based on the previous literature and our cases, we believe that the association between rapid reduction of intracranial pressure (ICP) and the development of PRES should be recognized because most neurosurgical procedures such as craniotomy or cerebrospinal fluid diversion present a potential risk of rapid reduction of ICP.
Transcriptomic and epigenetic dissection of spinal ependymoma (SP-EPN) identifies clinically relevant subtypes enriched for tumors with and without NF2 mutation
Ependymomas encompass multiple clinically relevant tumor types based on localization and molecular profiles. Tumors of the methylation class “spinal ependymoma” (SP-EPN) represent the most common intramedullary neoplasms in children and adults. However, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical relevance have been described in a large, epigenetically defined series. Transcriptomic ( n  = 72), epigenetic ( n  = 225), genetic ( n  = 134), and clinical data ( n  = 112) were integrated for a detailed molecular overview on SP-EPN. Additionally, we mapped SP-EPN transcriptomes to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. The integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord revealed that SP-EPN display the highest similarities to mature adult ependymal cells. Unsupervised hierarchical clustering of transcriptomic data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype A tumors primarily carried previously known germline or sporadic NF2 mutations together with 22q loss (bi-allelic NF2 loss), resulting in decreased NF2 expression. Furthermore, they more often presented as multilocular disease and demonstrated a significantly reduced progression-free survival as compared to SP-EP subtype B. In contrast, subtype B predominantly contained samples without NF2 mutation detected in sequencing together with 22q loss (monoallelic NF2 loss). These tumors showed regular NF2 expression but more extensive global copy number alterations. Based on integrated molecular profiling of a large multi-center cohort, we identified two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities.
MAIT cells have a negative impact on glioblastoma
Glioblastoma (GBM) is the most aggressive primary brain cancer in adults and remains incurable. Our study revealed an immunosuppressive role of mucosal-associated invariant T (MAIT) cells in GBM. In bulk RNA sequencing data analysis of GBM tissues, MAIT cell gene signature significantly correlated with poor patient survival. A scRNA-seq of CD45+ cells from 23 GBM tissue samples showed 15 (65.2%) were positive for MAIT cells and the enrichment of MAIT17. The MAIT cell signature significantly correlated with the activity of tumor-associated neutrophils (TANs) and myeloid-derived suppressor cells (MDSCs). Multiple immune suppressive genes known to be used by TANs/MDSCs were upregulated in MAIT-positive tumors. Spatial imaging analysis of GBM tissues showed that all specimens were positive for both MAIT cells and TANs and localized enrichment of TANs. These findings highlight the MAIT-TAN/MDSC axis as a novel therapeutic target to modulate GBM's immunosuppressive tumor microenvironment.Competing Interest StatementThe authors have declared no competing interest.Footnotes* Results from Multiplexed tissue imaging of glioblastoma patient specimens with Co-detection by indexing (CODEX) was included. The tissue imaging experiment showed that MAIT cells and neutrophils are found in the tumor of glioblastoma patients. In addition, to be consistent with the glioblastoma definition by WHO classification 2021, patient samples with reported IDH mutation were removed from TCGA dataset and the revised results were updated. MAIT cell signature genes were updated to include more MAIT cell marker genes which were reported by multiple independent studies.