The Role of γδ T-Lymphocytes in Glioblastoma: Current Trends and Future Directions

Cell-based immunotherapy for glioblastoma (GBM) encounters major challenges due to the infiltration-resistant and immunosuppressive tumor microenvironment (TME). γδ T cells, unconventional T cells expressing the characteristic γδ T cell receptor, have demonstrated promise in overcoming these challenges, suggesting great immunotherapeutic potential. This review presents the role of γδ T cells in GBM and proposes several research avenues for future studies. Using the PubMed, ScienceDirect, and JSTOR databases, we performed a review of the literature studying the biology of γδ T cells and their role in GBM treatment. We identified 15 studies focused on γδ T cells in human GBM. Infiltrative γδ T cells can incite antitumor immune responses in certain TMEs, though rapid tumor progression and TME hypoxia may impact the extent of tumor suppression. In the studies, available findings have shown both the potential for robust antitumor activity and the risk of protumor activity. While γδ T cells have potential as a therapeutic agent against GBM, the technical challenges of extracting, isolating, and expanding γδ T cells, and the activation of antitumoral versus protumoral cascades, remain barriers to their application. Overcoming these limitations may transform γδ T cells into a promising immunotherapy in GBM.

A future blood test for acute traumatic spinal cord injury

Acute spinal cord injury (SCI) requires prompt diagnosis and intervention to minimize the risk of permanent neurologic deficit. Presently, SCI diagnosis and interventional planning rely on magnetic resonance imaging (MRI), which is not always available or feasible for severely injured patients. Detection of disease-specific biomarkers in biofluids via liquid biopsy may provide a more accessible and objective means of evaluating patients with suspected SCI. Cell-free DNA, which has been used for diagnosing and monitoring oncologic disease, may detect damage to spinal cord neurons via tissue-specific methylation patterns. Other types of biomarkers, including proteins and RNA species, have also been found to reflect neuronal injury and may be included as part of a multi-analyte assay to improve liquid biopsy performance. The feasibility of implementing liquid biopsy into current practices of SCI management is supported by the relative ease of blood sample collection as well as recent advancements in droplet digital polymerase chain reaction technology. In this review, we detail the current landscape of biofluid biomarkers for acute SCI and propose a framework for the incorporation of a putative blood test into the clinical management of SCI.

Exome Sequencing Expands the Genetic Diagnostic Spectrum for Pediatric Hearing Loss

OBJECTIVES

Genetic testing is the standard-of-care for diagnostic evaluation of bilateral, symmetric, sensorineural hearing loss (HL). We sought to determine the efficacy of a comprehensive genetic testing method, exome sequencing (ES), in a heterogeneous pediatric patient population with bilateral symmetric, bilateral asymmetric, and unilateral HL.

METHODS

Trio-based ES was performed for pediatric patients with confirmed HL including those with symmetric, asymmetric, and unilateral HL.

RESULTS

ES was completed for 218 probands. A genetic cause was identified for 31.2% of probands (n = 68). The diagnostic rate was 40.7% for bilateral HL, 23.1% for asymmetric HL, and 18.3% for unilateral HL, with syndromic diagnoses made in 20.8%, 33.3%, and 54.5% of cases in each group, respectively. Secondary or incidental findings were identified in 10 families (5.52%).

CONCLUSION

ES is an effective method for genetic diagnosis for HL including phenotypically diverse patients and allows the identification of secondary findings, discovery of deafness-causing genes, and the potential for efficient data re-analysis.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2417-2424, 2023.

The impact of attending historically Black colleges and universities on cognitive decline in Black adults: A longitudinal analysis in the KHANDLE and STAR cohorts

INTRODUCTION

Black students attending predominantly White institutions (PWIs) versus historically Black colleges and universities (HBCUs) report more harmful discrimination and develop worse mental health outcomes, potentially offsetting the established benefits of college for lowering dementia incidence.

METHODS

Black participants in two cohorts (the Kaiser Healthy Aging and Diverse Life Experiences [KHANDLE] and the Study of Healthy Aging in African Americans [STAR]) who had attended college (N = 716) self-reported the college name (classified as HBCU vs. PWI) and completed three waves of executive function (EF) and verbal episodic memory (VEM) assessments. HBCU effects on cognitive level and decline were estimated using adjusted linear mixed-effects models.

RESULTS

HBCU (vs. PWI) attendees averaged better EF (β = 0.05 [-0.22, 0.32]) and VEM (β = 0.21 [-0.06, 0.46]) at age 70 though neither association was statistically significant. HBCU attendance was associated with slightly faster VEM decline (β = -0.03 [-0.05, 0.00]).

DISCUSSION

Harmonized analyses with larger studies are needed to estimate important effects of HBCU attendance.

HIGHLIGHTS

Higher education is robustly linked to lower dementia risk, yet Black-White inequities persist among college-educated adults. Black students attending predominantly White institutions (PWIs) versus historically Black colleges and universities (HBCUs) report more harmful discrimination and develop worse mental health outcomes, which may offset the established benefits of college for lowering dementia incidence. HBCU (vs. non-HBCU) attendees averaged better executive function and verbal episodic memory (VEM) at average age 70, though confidence intervals were wide and associations were not statistically significant, and averaged slightly faster decline in VEM. Harmonized analyses using larger nationally representative studies are likely needed to avoid underestimating the health effects of HBCU attendance.

Abstract B009: Sub-oxidant ascorbate sensitizes glioblastoma stem cells to DNA damaging agents by inducing DNA de-methylation and altering the chromatin landscape

Gliomas are the most common primary brain cancer and glioblastoma (GBM) represents the most aggressive and lethal subtype. The high GBM morbidity and mortality are due to profound genetic, epigenetic, and phenotypic heterogeneity within the tumor that contributes to an almost guaranteed development of therapeutic resistance and tumor recurrence. GBM stem-like cells (GSCs) are tumor cell sub-populations that disproportionately drive tumor propagation, therapy resistance, and tumor recurrence. Epigenetic deregulation is thought to play a fundamental role in the formation and expansion of GSCs and their contributions to oncogenesis. However, the epigenetic reprogramming events that contribute to GSC tumor propagation and therapy resistance remain elusive. DNA methylation (5mC) can be modified to generate hydroxymethylation (5hmC) or reversed through enzymatic reactions coordinated by the Ten-Eleven Translocation (TET) enzymes. Multiple studies show a decrease in both 5hmC levels and TET expression in gliomas and a correlation between loss of 5hmC and increasing glioma grade and poor prognosis. These observations suggest that re-establishing TET activity and 5hmC levels in tumor cells will have tumor suppressive effects. Ascorbate (vitamin C) has gained pre-clinical interest as an attractive antitumor agent for GBM due to its ability to regulate redox status, cross the blood-brain barrier, and enhance TET enzymatic activity; therefore, providing an innovative potential epigenetic therapeutic for GBM. We show that low-dose ascorbate (i.e. sub-pro-oxidant concentrations) enhances TET activity and elevates global 5hmC levels concurrent with decreases in 5mC in GSCs. These changes in DNA methylation correlate with a decrease in self-renewal capacity and increased tumor cell death induced by temozolomide (TMZ) and ionizing radiation (IR). We also present a novel mechanism whereby ascorbate increases the histone mark H3K36me3 by upregulating GSC expression of the histone methyltransferase NSD1 via demethylation of the gene promoter region. We propose that the enhanced susceptibility of ascorbate-treated tumor cells to DNA damage therapies results from increased H3K36me3-induced euchromatin states that increases genomic susceptibility to DNA damage. These findings support the need to better understand the epigenetic, transcriptomic, and chromatin architectural effects of ascorbate in cancer. These results also strongly indicate that ascorbate could serve as an adjunct to standard-of-care GBM treatment by restoring TET tumor-suppressor activity and re-sensitizing GSCs to conventional radio- and chemotherapeutics.

Citation Format: Maureen Malloy, Sweta Sudhir, Harmon Khela, Maria Fagundo-Lugo, Bachchu Lal, Joseph Bressler, John Laterra, Hernando Lopez Bertoni. Sub-oxidant ascorbate sensitizes glioblastoma stem cells to DNA damaging agents by inducing DNA de-methylation and altering the chromatin landscape. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B009.

A descriptive analysis of 2020 California Occupational Safety and Health Administration covid-19-related complaints

COVID-19 mortality has disproportionately affected specific occupations and industries. The Occupational Safety and Health Administration (OSHA) protects the health and safety of workers by setting and enforcing standards for working conditions. Workers may file OSHA complaints about unsafe conditions. Complaints may indicate poor workplace safety during the pandemic. We evaluated COVID-19-related complaints filed with California (Cal)/OSHA between January 1, 2020 and December 14, 2020 across seven industries. To assess whether workers in occupations with high COVID-19-related mortality were also most likely to file Cal/OSHA complaints, we compared industry-specific per-capita COVID-19 confirmed deaths from the California Department of Public Health with COVID-19-related complaints. Although 7820 COVID-19-related complaints were deemed valid by Cal/OSHA, only 627 onsite inspections occurred, and 32 citations were issued. Agricultural workers had the highest per-capita COVID-19 death rates (402 per 100,000 workers) but were least represented among workplace complaints (44 per 100,000 workers). Health Care workers had the highest complaint rates (81 per 100,000 workers) but the second lowest COVID-19 death rate (81 per 100,000 workers). Industries with the highest inspection rates also had high COVID-19 mortality. Our findings suggest complaints are not proportional to COVID-19 risk. Instead, higher complaint rates may reflect worker groups with greater empowerment, resources, or capacity to advocate for better protections. This capacity to advocate for safe workplaces may account for relatively low mortality rates in potentially high-risk occupations. Future research should examine factors determining worker complaints and complaint systems to promote participation of those with the greatest need of protection.

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COVID-19 mortality disproportionately affected specific occupations and industries.

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Cal/OSHA workplace complaint system may indicate poor workplace safety during the pandemic.

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Overall, complaints varied markedly by industry and rarely resulted in inspection or citation.

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High COVID-19-related complaint rates did not align with the highest COVID-19 death rates.

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Complaints filed to Cal/OSHA may better reflect employee resources than COVID-19 risk.

A descriptive analysis of 2020 California Occupational Safety and Health Administration COVID-19-related complaints.. [PMID: 34909780 PMCID: PMC8669847 DOI: 10.1101/2021.12.06.21262384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

COVID-19 mortality disproportionately affected specific occupations and industries. The Occupational Safety and Health Administration (OSHA) protects the health and safety of workers by setting and enforcing standards for working conditions. Workers may file OSHA complaints about unsafe conditions. Complaints may indicate poor workplace safety during the pandemic. We evaluated COVID-19-related complaints filed with California (Cal)/OSHA between January 1, 2020 and December 14, 2020 across seven industries. To assess whether workers in occupations with high COVID-19-related mortality were also most likely to file Cal/OSHA complaints, we compared industry-specific per-capita COVID-19 confirmed deaths from the California Department of Public Health with COVID-19-related complaints. Although 7,820 COVID-19-related complaints were deemed valid by Cal/OSHA, only 627 onsite inspections occurred and 32 citations were issued. Agricultural workers had the highest per-capita COVID-19 death rates (402 per 100,000 workers) but were least represented among workplace complaints (44 per 100,000 workers). Health Care workers had the highest complaint rates (81 per 100,000 workers) but the second lowest COVID-19 death rate (81 per 100,000 workers). Industries with the highest inspection rates also had high COVID-19 mortality. Our findings suggest complaints are not proportional to COVID-19 risk. Instead, higher complaint rates may reflect worker groups with greater empowerment, resources, or capacity to advocate for better protections. This capacity to advocate for safe workplaces may account for relatively low mortality rates in potentially high-risk occupations. Future research should examine factors determining worker complaints and complaint systems to promote participation of those with the greatest need of protection.

Biomarkers and focused ultrasound: the future of liquid biopsy for brain tumor patients

Introduction

Despite advances in modern medicine, brain tumor patients are still monitored purely by clinical evaluation and imaging. Traditionally, invasive strategies such as open or stereotactic biopsies have been used to confirm the etiology of clinical and imaging changes. Liquid biopsies can enable physicians to noninvasively analyze the evolution of a tumor and a patient’s response to specific treatments. However, as a consequence of biology and the current limitations in detection methods, no blood or cerebrospinal fluid (CSF) brain tumor-derived biomarkers are used in routine clinical practice. Enhancing the presence of tumor biomarkers in blood and CSF via brain-blood barrier (BBB) disruption with MRI-guided focused ultrasound (MRgFUS) is a very compelling strategy for future management of brain tumor patients.

Methods

A literature review on MRgFUS-enabled brain tumor liquid biopsy was performed using Medline/Pubmed databases and clinical trial registries.

Results

The therapeutic applications of MRgFUS to target brain tumors have been under intense investigation. At high-intensity, MRgFUS can ablate brain tumors and target tissues, which needs to be balanced with the increased risk for damage to surrounding normal structures. At lower-intensity and pulsed-frequency, MRgFUS may be able to disrupt the BBB transiently. Thus, while facilitating intratumoral or parenchymal access to standard or novel therapeutics, BBB disruption with MRgFUS has opened the possibility of enhanced detection of brain tumor-derived biomarkers.

Conclusions

In this review, we describe the concept of MRgFUS-enabled brain tumor liquid biopsy and present the available preclinical evidence, ongoing clinical trials, limitations, and future directions of this application.

Abstract 2124: Vitamin C enhances H3K36me3 via NSD1 promoter demethylation and sensitizes GBM stem cells to DNA damaging agents

Primary brain tumors are among the most devastating forms of cancer. Due to profound genetic, epigenetic, and morphologic heterogeneity, GBM represents the most aggressive and lethal form of the disease. GBM exhibits aberrant patterns of DNA methylation, resulting in a highly distorted epigenome, yet the molecular circuits responsible for this epigenetic dysregulation remain unknown. Glioma stem cells (GSCs) are critical modulators of tumor propagation and therapeutic resistance in GBM, and epigenetic deregulation within this cell subpopulation is thought to play fundamental roles in GSC and GBM biology. Understanding and overcoming these tumorigenic epigenetic mechanisms in GSCs is crucial to developing more effective treatment protocols and improving clinical survival. DNA methylation is a reversible process involving the addition of methyl groups, typically, at cytosine residues and demethylation is catalyzed, in part, by the ten-eleven translocation (TET) family of enzymes. These enzymes function as deoxygenases that convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Multiple studies show negative correlations between 5hmC levels and glioma grade, and loss of 5hmC correlates with poor prognosis of GBM patients. These observations suggest that understanding the mechanisms of 5hmC deregulation in GBM and developing innovative ways to re-establish 5hmC levels in tumors can impact patient outcome. Ascorbate (Vitamin C) is a TET enzyme cofactor that has gained pre-clinical interest as an attractive antitumor agent for GBM due to its ability to regulate redox status, function as potent demethylating agent, and efficiently penetrate the blood-brain barrier. We show through various molecular and biochemical endpoints, that low-dose Vitamin C significantly replenishes 5hmC and decreases stemness in GSCs. We found that, in addition to increasing global levels of 5hmC, low-dose Vitamin C acts synergistically with temozolomide (TMZ) and irradiation to induce cell death in GSCs. We also present a novel mechanism whereby Vitamin C regulates promoter demethylation of the histone methyltransferase NSD1 resulting in an increase in H3K36me3 in GSCs. We propose the increase in H3K36me3 results in euchromatin states that are more susceptible to DNA damage therapies. Our findings strongly indicate that Vitamin C can undo tumor-promoting DNA hypermethylation and sensitize GSCs to conventional radio- and chemotherapeutics and suggest it might serve as an adjunct to standard-of-care GBM treatment.

Citation Format: Harmon Khela, Sweta Sudhir, Maria Fagundo-Lugo, Bachchu Lal, John Laterra, Hernando Lopez-Bertoni. Vitamin C enhances H3K36me3 via NSD1 promoter demethylation and sensitizes GBM stem cells to DNA damaging agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2124.

STEM-27. miR-10b-5p MODULATES 5hmC EXPRESSION AND THE STEM-LIKE PHENOTYPE IN GBM

Epigenetic alterations such as DNA methylation and dysregulation of non-coding RNAs (e.g. miRNAs) are found in all types of cancer and are thought to play important roles in tumorigenesis. GBM is characterized by small subsets of cells, referred to as glioma stem cells (GSCs), that display stem-like properties implicated in tumor initiation, therapeutic resistance, and recurrence. DNA methylation patterns are altered in GBM and GSCs and are thought to play critical roles in tumor initiation and propagation. DNA methylation is a reversible process catalyzed, in part, by the ten-eleven translocation (TET) family of enzymes. These enzymes function as deoxygenases that catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Multiple studies found negative correlations between 5hmC levels and glioma grade and loss of 5hmC correlates with poor prognosis of GBM patients. However, the mechanisms leading to the loss of 5hmC in glioma and the role this phenomenon plays in gliomagenesis remains poorly understood. We found that Sox2 expression decreases TET2 expression and its product 5hmC in GSCs and identified miR-10b-5p as a molecular intermediary of this process. We show that miR-10b-5p expression is high in GBM compared to non-tumor in clinical specimens and high levels of this miRNA correlate with poor patient outcome. Expression of transgenic miR-10b-5p enhanced sphere formation capacity of GSCs and the expression of stem cell markers and drivers. Additionally, using a combination of molecular and biochemical endpoints, we show that miR-10b-5p modifies 5hmC levels by regulating TET2 in GSCs. Finally, we show that repression of miR-10b-5p increases 5hmC levels and inhibits tumor propagation in GBM xenograft models. Taken together, these results present a new molecular mechanism that controls 5hmC and the tumor propagating capacity of GSCs and suggests that miR-10b-5p inhibition and other strategies for enhancing TET2 function can be developed to treat GBM.

Genetics of pediatric hearing loss: A functional perspective

OBJECTIVES

This article reviews the current role of genetics in pediatric hearing loss (HL).

METHODS

A review of the current literature regarding the genetic basis of HL in children was performed.

RESULTS

To date, 119 nonsyndromic genes have been associated with HL. There are also hundreds of syndromic causes that have HL as part of the clinical phenotype.

CONCLUSIONS

Identifying HL genes coupled with clinical characteristics ("genotype-phenotype") yields a more accurate diagnosis and prognosis. Although the complexity of the auditory apparatus presents challenges, gene therapy is emerging and may be a viable management option in the future.