Characterizing Cell Stress and GRP78 in Glioma to Enhance Tumor Treatment

Targeting the organelle for radiosensitization in cancer radiotherapy

Radiotherapy is a well-established cytotoxic therapy for local solid cancers, utilizing high-energy ionizing radiation to destroy cancer cells. However, this method has several limitations, including low radiation energy deposition, severe damage to surrounding normal cells, and high tumor resistance to radiation. Among various radiotherapy methods, boron neutron capture therapy (BNCT) has emerged as a principal approach to improve the therapeutic ratio of malignancies and reduce lethality to surrounding normal tissue, but it remains deficient in terms of insufficient boron accumulation as well as short retention time, which limits the curative effect. Recently, a series of radiosensitizers that can selectively accumulate in specific organelles of cancer cells have been developed to precisely target radiotherapy, thereby reducing side effects of normal tissue damage, overcoming radioresistance, and improving radiosensitivity. In this review, we mainly focus on the field of nanomedicine-based cancer radiotherapy and discuss the organelle-targeted radiosensitizers, specifically including nucleus, mitochondria, endoplasmic reticulum and lysosomes. Furthermore, the organelle-targeted boron carriers used in BNCT are particularly presented. Through demonstrating recent developments in organelle-targeted radiosensitization, we hope to provide insight into the design of organelle-targeted radiosensitizers for clinical cancer treatment.

Mitochondrial Mechanisms in Temozolomide Resistance: Unraveling the Complex Interplay and Therapeutic Strategies in Glioblastoma

Glioblastoma (GBM) is a highly aggressive and lethal brain tumor, with temozolomide (TMZ) being the standard chemotherapeutic agent for its treatment. However, TMZ resistance often develops, limiting its therapeutic efficacy and contributing to poor patient outcomes. Recent evidence highlights the crucial role of mitochondria in the development of TMZ resistance through various mechanisms, including alterations in reactive oxygen species (ROS) production, metabolic reprogramming, apoptosis regulation, biogenesis, dynamics, stress response, and mtDNA mutations. This review article aims to provide a comprehensive overview of the mitochondrial mechanisms involved in TMZ resistance and discuss potential therapeutic strategies targeting these mechanisms to overcome resistance in GBM. We explore the current state of clinical trials targeting mitochondria or related pathways in primary GBM or recurrent GBM, as well as the challenges and future perspectives in this field. Understanding the complex interplay between mitochondria and TMZ resistance will facilitate the development of more effective therapeutic strategies and ultimately improve the prognosis for GBM patients.

Role of cytosolic and endoplasmic reticulum Ca2+ in pancreatic beta-cells: pros and cons

Pancreatic beta cells utilize Ca2+ to secrete insulin in response to glucose. The glucose-dependent increase in cytosolic Ca2+ concentration ([Ca2+]C) activates a series of insulin secretory machinery in pancreatic beta cells. Therefore, the amount of insulin secreted in response to glucose is determined in a [Ca2+]C-dependent manner, at least within a moderate range. However, the demand for insulin secretion may surpass the capability of beta cells. Abnormal elevation of [Ca2+]C levels beyond the beta-cell endurance capacity can damage them by inducing endoplasmic reticulum (ER) stress and cell death programs such as apoptosis. Therefore, while Ca2+ is essential for the insulin secretory functions of beta cells, it could affect their survival at pathologically higher levels. Because an increase in beta-cell [Ca2+]C is inevitable under certain hazardous conditions, understanding the regulatory mechanism for [Ca2+]C is important. Therefore, this review discusses beta-cell function, survival, ER stress, and apoptosis associated with intracellular and ER Ca2+ homeostasis.

Flavopiridol Suppresses Cell Proliferation and Migration and Induces Apoptotic Cell Death by Inhibiting Oncogenic FOXM1 Signaling in IDH Wild-Type and IDH-Mutant GBM Cells

Glioblastoma multiforme (GBM) remains one of the most challenging solid cancers to treat due to its highly aggressive and drug-resistant nature. Flavopiridol is synthetic flavone that was recently approved by the FDA for the treatment of acute myeloid leukemia. Flavopiridol exhibits antiproliferative activity in several solid cancer cells and currently evaluated in clinical trials in several solid and hematological cancers. In this study, we investigated the molecular mechanisms underlying antiproliferative effects of flavopiridol in GBM cell lines with wild-type and mutant encoding isocitrate dehydrogenase 1 (IDH1). We found that flavopiridol inhibits proliferation, colony formation, and migration and induces apoptosis in IDH1 wild-type and IDH-mutant cells through inhibition of FOXM1 oncogenic signaling. Furthermore, flavopiridol treatment also inhibits of NF-KB, mediators unfolded protein response (UPR), including, GRP78, PERK and IRE1α, and DNA repair enzyme PARP, which have been shown to be potential therapeutic targets by downregulating FOXM1 in GBM cells. Our findings suggest for the first time that flavopiridol suppresses proliferation, survival, and migration and induces apoptosis in IDH1 wild-type and IDH1-mutant GBM cells by targeting FOXM1 oncogenic signaling which also regulates NF-KB, PARP, and UPR response in GBM cells. Flavopiridol may be a potential novel therapeutic strategy in the treatment of patients IDH1 wild-type and IDH1-mutant GBM.

Chimeric Antigen Receptor T Cell and Chimeric Antigen Receptor NK Cell Therapy in Pediatric and Adult High-Grade Glioma-Recent Advances

High-grade gliomas (HGG) account for approximately 10% of central nervous system (CNS) tumors in children and 25% of CNS tumors in adults. Despite their rare occurrence, HGG are a significant clinical problem. The standard therapeutic procedure in both pediatric and adult patients with HGG is the surgical resection of the tumor combined with chemotherapy and radiotherapy. Despite intensive treatment, the 5-year overall survival in pediatric patients is below 20-30%. This rate is even lower for the most common HGG in adults (glioblastoma), at less than 5%. It is, therefore, essential to search for new therapeutic methods that can extend the survival rate. One of the therapeutic options is the use of immune cells (T lymphocytes/natural killer (NK) cells) expressing a chimeric antigen receptor (CAR). The objective of the following review is to present the latest results of preclinical and clinical studies evaluating the efficacy of CAR-T and CAR-NK cells in HGG therapy.

Cellular stress responses as modulators of drug cytotoxicity in pharmacotherapy of glioblastoma

Despite the extensive efforts to find effective therapeutic strategies, glioblastoma (GBM) remains a therapeutic challenge with dismal prognosis of survival. Over the last decade the role of stress responses in GBM therapy has gained a great deal of attention, since depending on the duration and intensity of these cellular programs they can be cytoprotective or promote cancer cell death. As such, initiation of the UPR, autophagy or oxidative stress may either impede or facilitate drug-mediated cell killing. In this review, we summarize the mechanisms that regulate ER stress, autophagy, and oxidative stress during GBM development and progression to later discuss the involvement of these stress pathways in the response to different treatments. We also discuss how a precise understanding of the molecular mechanisms regulating stress responses evoked by different pharmacological agents could decisively contribute to the design of novel and more effective combinational treatments against brain malignancies.

Pterostilbene as a Therapeutic Alternative for Central Nervous System Disorders: A Review of the Current Status and Perspectives

Neurological disorders are diverse, have complex causes, and often result in disability; yet, effective treatments remain scarce. The resveratrol derivative pterostilbene possesses numerous physiological activities that hold promise as a novel therapy for the central nervous system (CNS) disorders. This review aimed to summarize the protective mechanisms of pterostilbene in in vitro and in vivo models of CNS disorders and the pharmacokinetics and safety to assess its possible effects on CNS disorders. Available evidence supports the protective effects of pterostilbene in CNS disorders involving mechanisms such as antioxidant and anti-inflammatory activity, regulation of lipid metabolism and vascular smooth muscle cell proliferation, improvement of synaptic function and neurogenesis, induction of glioma cell cycle arrest, and inhibition of glioma cell migration and invasion. Studies have identified possible molecular targets and pathways for the protective actions of pterostilbene in CNS disorders including the AMPK/STAT3, Akt, NF-κB, MAPK, and ERK signaling pathways. The possible pharmacological effects and molecular pathways of pterostilbene in CNS disorders are critically discussed in this review. Future studies should aim to increase our understanding of pterostilbene in animal models and humans to further evaluate its role in CNS disorders and the detailed mechanisms.

Unveiling the dark side of glucose-regulated protein 78 (GRP78) in cancers and other human pathology: a systematic review

Glucose-Regulated Protein 78 (GRP78) is a chaperone protein that is predominantly expressed in the lumen of the endoplasmic reticulum. GRP78 plays a crucial role in protein folding by assisting in the assembly of misfolded proteins. Under cellular stress conditions, GRP78 can translocate to the cell surface (csGRP78) were it interacts with different ligands to initiate various intracellular pathways. The expression of csGRP78 has been associated with tumor initiation and progression of multiple cancer types. This review provides a comprehensive analysis of the existing evidence on the roles of GRP78 in various types of cancer and other human pathology. Additionally, the review discusses the current understanding of the mechanisms underlying GRP78's involvement in tumorigenesis and cancer advancement. Furthermore, we highlight recent innovative approaches employed in downregulating GRP78 expression in cancers as a potential therapeutic target.

Chimeric antigen receptor T cells targeting cell surface GRP78 efficiently kill glioblastoma and cancer stem cells

BACKGROUND

Glioblastoma (GBM) is recognized as among the most aggressive forms of brain tumor. Patients typically present with a five-year survival rate of less than 6% with traditional surgery and chemoradiotherapy, which calls for novel immunotherapies like chimeric antigen receptor T (CAR-T) cells therapy. In response to endoplasmic reticulum (ER) stress in multiple tumor cells including GBM, the glucose-regulated protein 78 (GRP78) expression increases and the protein is partially translocated to the cell surface, while it is restricted to the cytoplasm and the nucleus in normal cells.

METHODS

In this study, to target the cell surface GRP78 (csGRP78), CAR-T cells based on its binding peptide were generated. In vitro two GBM cell lines and glioma stem cells (GSCs) were used to confirm the localization of csGRP78 and the cytotoxicity of the CAR-T cells. In vivo a GBM xenograft model was used to assess the killing activity and the safety of the CAR-T cells.

RESULTS

We confirmed the localization of csGRP78 at the cell surface of two GBM cell lines (U-251MG and U-87MG) and in GSCs. Co-culture experiments revealed that the CAR-T cells could specifically kill the GBM tumor cells and GSCs with specific IFN-γ release. Furthermore, in the tumor xenograft model, the CAR-T cells could decrease the number of GSCs and significantly suppress tumor cell growth. Importantly, we found no obvious off-target effects or T cell infiltration in major organs following systemic administration of these cells.

CONCLUSIONS

The csGRP78 targeted CAR-T cells efficiently kill GBM tumor cells and GSCs both in vitro and in vivo, and ultimately suppress the xenograft tumors growth without obvious tissue injuries. Therefore, our study demonstrates that csGRP78 represents a valuable target and the csGRP78-targeted CAR-T cells strategy is an effective immunotherapy against GBM.

Functionalized nanoparticles crossing the brain-blood barrier to target glioma cells

Glioma is the most common tumor of the central nervous system (CNS), with a 5-year survival rate of <35%. Drug therapy, such as chemotherapeutic and immunotherapeutic agents, remains one of the main treatment modalities for glioma, including temozolomide, doxorubicin, bortezomib, cabazitaxel, dihydroartemisinin, immune checkpoint inhibitors, as well as other approaches such as siRNA, ferroptosis induction, etc. However, the filter function of the blood-brain barrier (BBB) reduces the amount of drugs needed to effectively target CNS tumors, making it one of the main reasons for poor drug efficacies in glioma. Thus, finding a suitable drug delivery platform that can cross the BBB, increase drug aggregation and retainment in tumoral areas and avoid accumulation in non-targeted areas remains an unsolved challenge in glioma drug therapy. An ideal drug delivery system for glioma therapy should have the following features: (1) prolonged drug life in circulation and effective penetration through the BBB; (2) adequate accumulation within the tumor (3) controlled-drug release modulation; (4) good clearance from the body without significant toxicity and immunogenicity, etc. In this regard, due to their unique structural features, nanocarriers can effectively span the BBB and target glioma cells through surface functionalization, providing a new and effective strategy for drug delivery. In this article, we discuss the characteristics and pathways of different nanocarriers for crossing the BBB and targeting glioma by listing different materials for drug delivery platforms, including lipid materials, polymers, nanocrystals, inorganic nanomaterials, etc.

Combining Pr3+-Doped Nanoradiosensitizers and Endogenous Protoporphyrin IX for X-ray-Mediated Photodynamic Therapy of Glioblastoma Cells

Glioblastoma multiforme is an aggressive type of brain cancer with high recurrence rates due to the presence of radioresistant cells remaining after tumor resection. Here, we report the development of an X-ray-mediated photodynamic therapy (X-PDT) system using NaLuF₄:25% Pr³⁺ radioluminescent nanoparticles in conjunction with protoporphyrin IX (PPIX), an endogenous photosensitizer that accumulates selectively in cancer cells. Conveniently, 5-aminolevulinic acid (5-ALA), the prodrug that is administered for PDT, is the only drug approved for fluorescence-guided resection of glioblastoma, enabling dual detection and treatment of malignant cells. NaLuF₄:Pr³⁺ nanoparticles were synthesized and spectroscopically evaluated at a range of Pr³⁺ concentrations. This generated radioluminescent nanoparticles with strong emissions from the ¹S₀ excited state of Pr³⁺, which overlaps with the Soret band of PPIX to perform photodynamic therapy. The spectral overlap between the nanoparticles and PPIX improved treatment outcomes for U251 cells, which were used as a model for the thin tumor margin. In addition to sensitizing PPIX to induce X-PDT, our nanoparticles exhibit strong radiosensitizing properties through a radiation dose-enhancement effect. We evaluate the effects of the nanoparticles alone and in combination with PPIX on viability, death, stress, senescence, and proliferation. Collectively, our results demonstrate this as a strong proof of concept for nanomedicine.

The anterior gradient homologue 2 (AGR2) co-localises with the glucose-regulated protein 78 (GRP78) in cancer stem cells, and is critical for the survival and drug resistance of recurrent glioblastoma: in situ and in vitro analyses

BACKGROUND

Glioblastomas (GBs) are characterised as one of the most aggressive primary central nervous system tumours (CNSTs). Single-cell sequencing analysis identified the presence of a highly heterogeneous population of cancer stem cells (CSCs). The proteins anterior gradient homologue 2 (AGR2) and glucose-regulated protein 78 (GRP78) are known to play critical roles in regulating unfolded protein response (UPR) machinery. The UPR machinery influences cell survival, migration, invasion and drug resistance. Hence, we investigated the role of AGR2 in drug-resistant recurrent glioblastoma cells.

METHODS

Immunofluorescence, biological assessments and whole exome sequencing analyses were completed under in situ and in vitro conditions. Cells were treated with CNSTs clinical/preclinical drugs taxol, cisplatin, irinotecan, MCK8866, etoposide, and temozolomide, then resistant cells were analysed for the expression of AGR2. AGR2 was repressed using single and double siRNA transfections and combined with either temozolomide or irinotecan.

RESULTS

Genomic and biological characterisations of the AGR2-expressed Jed66_GB and Jed41_GB recurrent glioblastoma tissues and cell lines showed features consistent with glioblastoma. Immunofluorescence data indicated that AGR2 co-localised with the UPR marker GRP78 in both the tissue and their corresponding primary cell lines. AGR2 and GRP78 were highly expressed in glioblastoma CSCs. Following treatment with the aforementioned drugs, all drug-surviving cells showed high expression of AGR2. Prolonged siRNA repression of a particular region in AGR2 exon 2 reduced AGR2 protein expression and led to lower cell densities in both cell lines. Co-treatments using AGR2 exon 2B siRNA in conjunction with temozolomide or irinotecan had partially synergistic effects. The slight reduction of AGR2 expression increased nuclear Caspase-3 activation in both cell lines and caused multinucleation in the Jed66_GB cell line.

CONCLUSIONS

AGR2 is highly expressed in UPR-active CSCs and drug-resistant GB cells, and its repression leads to apoptosis, via multiple pathways.

A Signaling Crosstalk Links SNAIL to the 37/67 kDa Laminin-1 Receptor Ribosomal Protein SA and Regulates the Acquisition of a Cancer Stem Cell Molecular Signature in U87 Glioblastoma Neurospheres

Background: Three-dimensional in vitro neurospheres cultures recapitulate stemness features associated with poor clinical outcome in glioblastoma patients. They are commonly used to address brain cancer stem cell (CSC) signal transducing biology that regulates spheroids formation and stemness phenotype, and to assess the in vitro pharmacological impact of chemotherapeutic drugs. Objective: Here, we addressed the role of a new signaling axis involved in the regulation of in vitro spheroids formation and assessed the chemopreventive ability of diet-derived epigallocatechin gallate (EGCG) to impact the processes that govern the acquisition of spheroids CSC stemness traits. Methods: Neurospheres were generated from adherent human U87 glioblastoma cancer cell cultures under conditions that recapitulate stemness features. Total RNA and protein lysates were isolated for gene expression by RT-qPCR and protein expression by immunoblot. Transcriptomic analysis was performed through RNA-Seq. Results: Compared to their parental adherent cells, tumorspheres expressed increased levels of the CSC markers NANOG, SOX2, PROM1 (CD133), as well as of the epithelial-to-mesenchymal transition (EMT) markers Fibronectin, SNAI1, and 37/67 kDa laminin-1 receptor ribosomal protein SA (RPSA). Increased PROM1, SOX2, Fibronectin, and RPSA transcripts level were also observed in clinical grade IV glioblastoma tissues compared to normal tissue. EGCG treatment reduced dose-dependently tumorspheres size and inhibited the transcriptional regulation of those genes. An apoptotic signature was also found in spheroids with increased signal transducing events involving GSK3α/β, RSK, and CREB. These were repressed upon RPSA gene silencing and partially by SNAI1 silencing. Conclusion: This work highlights a signaling axis linking RPSA upstream of SNAIL in neurospheres genesis and supports the chemopreventive impact that diet-derived EGCG may exert on the acquisition of CSC traits.

GRP78 Activity Moderation as a Therapeutic Treatment against Obesity

Glucose-regulated protein 78 (GRP78), a molecular chaperone, is overexpressed in patients suffering from obesity, fatty liver, hyperlipidemia and diabetes. GRP78, therefore, can be not only a biomarker to predict the progression and prognosis of obesity and metabolic diseases but also a potential therapeutic target for anti-obesity treatment. In this paper, GRP78 inhibitors targeting its ATPase domain have been reviewed. Small molecules and proteins that directly bind GRP78 have been described. Putative mechanisms of GRP78 in regulating lipid metabolism were also summarized so as to investigate the role of GRP78 in obesity and other related diseases and provide a theoretical basis for the development and design of anti-obesity drugs targeting GRP78.

Folate enzyme MTHFD2 links one-carbon metabolism to unfolded protein response in glioblastoma

The mitochondrial folate enzyme methylenetetrahydrofolate dehydrogenase/cyclohydrolase (MTHFD2) has shown oncogenic roles in various cancers and may have non-metabolic functions. This study investigated the role of MTHFD2 in glioblastoma pathogenesis. We find that MTHFD2 expression is enriched in gliomas by analysing public databases and clinical specimens. RNA interference (RNAi) and inhibitor of MTHFD2 hamper the proliferation of glioblastoma and induce apoptosis in cell lines, glioma stem-like cells (GSCs) and patient-derived xenografts (PDX). Metabolomic analyses show that MTHFD2 depletion suppresses the central carbon metabolic pathways, including glycolysis, the pentose phosphate pathway (PPP), and the tricarboxylic acid (TCA) cycle. GSEA reveals a novel non-metabolic function of MTHFD2 in association with the unfolded protein response (UPR). MTHFD2 depletion activates the PERK/eIF2α axis which contributes to translation inhibition and apoptosis; these effects are attenuated by a PERK inhibitor. Mechanistically, MTHFD2 may be linked to UPR via the post-transcriptionally regulation of chaperone protein GRP78. In conclusion, MTHFD2 could be a promising therapeutic target for glioblastoma. Besides its canonical role, MTHFD2 may contribute to glioblastoma pathogenesis via UPR, highlighting a newly identified functional link between one-carbon metabolism and cell stress response.

Chaperone protein P4HB predicts temozolomide response and prognosis in malignant glioma

Prolyl 4-hydroxylase beta polypeptide (P4HB) is a chaperone protein associated with temozolomide (TMZ) resistance through the unfolded protein response. Cancer cells with constitutive activation of endoplasmic reticulum stress and upregulation of P4HB have been observed to show resistance against chemotherapies. The present study focused on the evaluation of the prognostic value of P4HB in subtypes of glioma with or without O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. P4HB expression was assessed by immunohistochemical staining in 73 grade I-IV gliomas and its association with the clinicopathological data was determined. It was indicated that P4HB expression was significantly associated with several parameters, including age, tumour grade and the number of TMZ treatment cycles received. In the Kaplan-Meier analysis, P4HB expression was positively associated with risk of mortality and disease progression. In patients treated with TMZ, high P4HB expression was significantly associated with poor overall survival (OS) and progression-free survival (PFS). The association between MGMT promoter methylation and P4HB expression was also assessed. Patients with MGMT^MethP4HB^Low tumours had the most favourable PFS (48 months) among cases with various combinations of MGMT methylation status and P4HB expression. Multivariate analysis revealed that P4HB may be used as an independent prognostic indicator of OS, particularly in high-grade gliomas. The present study uncovered the potential role of P4HB in a nuanced pathological stratification during clinical decision-making with respect to MGMT promoter methylation status and TMZ treatment.

A Novel Localization in Human Large Extracellular Vesicles for the EGF-CFC Founder Member CRIPTO and Its Biological and Therapeutic Implications

Tumor growth and metastasis strongly rely on cell–cell communication. One of the mechanisms by which tumor cells communicate involves the release and uptake of lipid membrane encapsulated particles full of bioactive molecules, called extracellular vesicles (EVs). EV exchange between cancer cells may induce phenotype changes in the recipient cells. Our work investigated the effect of EVs released by teratocarcinoma cells on glioblastoma (GBM) cells. EVs were isolated by differential centrifugation and analyzed through Western blot, nanoparticle tracking analysis, and electron microscopy. The effect of large EVs on GBM cells was tested through cell migration, proliferation, and drug-sensitivity assays, and resulted in a specific impairment in cell migration with no effects on proliferation and drug-sensitivity. Noticeably, we found the presence of the EGF-CFC founder member CRIPTO on both small and large EVs, in the latter case implicated in the EV-mediated negative regulation of GBM cell migration. Our data let us propose a novel route and function for CRIPTO during tumorigenesis, highlighting a complex scenario regulating its effect, and paving the way to novel strategies to control cell migration, to ultimately improve the prognosis and quality of life of GBM patients.

Ascendancy of unfolded protein response over glioblastoma: estimating progression, prognosis and survival

Glioblastoma (GBM) is presented with a poor prognosis. The endoplasmic reticulum stress (ERS) has been implicated as a major contributor to disease progression and chemoresistance in GBM. Triggering ERS by chemical agents or genetic modulations is identified as some of the reasons for regulating gene expression and the pathogenesis of GBM. ERS initiates unfolded protein response (UPR), an integrated system useful in restoring homeostasis or inducing apoptosis. Modulation of UPR might have positive outcomes in GBM treatment as UPR inducers have been shown to alter cell survival and migration. In the current review, we have utilized GSE7806, a publicly available dataset from Gene Expression Omnibus (GEO), to evaluate the genes expressed during 6.5 hr and 18 hr, which can be comparable to the early and late-onset of the disease. Subsequently, we have elucidated the prognosis and survival information whilst the expression of these genes in the GBM was noted in previous studies. This is the first of its kind review summarizing the most recent gene information correlating UPR and GBM.

Ketamine-induced neurotoxicity is mediated through endoplasmic reticulum stress in vitro in STHdhQ7/Q7 cells

Ketamine has traditionally been used as a dissociative anesthetic agent and more recently as a treatment for treatment-resistant depression. However, there is growing concern over the increased use of ketamine in recreational and therapeutic settings due to the potential neurotoxic effects. Recent studies have demonstrated that ketamine is cytotoxic in several cell types, such as fibroblasts, hepatocytes, uroepithelial cells, and adult induced pluripotent stem cells (iPSCs). Ketamine has been shown to dysregulate calcium signalling, increase reactive oxygen species (ROS) production, and impair mitochondrial function, ultimately leading to apoptosis. However, it is unclear whether endoplasmic reticulum (ER) stress plays a role in ketamine associated neurotoxicity in striatal neurons. Disruption to ER homeostasis can initiate ER-mediated cell death, which has been implicated in several neurodegenerative diseases. Thus, the purpose of this study was to determine whether ketamine's neurotoxic effects involve an ER stress-dependent pathway and to elucidate the underlying mechanisms involved in its neurotoxic effects. Mouse striatal cells were treated with various concentrations of ketamine (10 μM, 100 μM, 1 mM) or DMEM for 9-72 hrs. Cell viability was assessed using the MTT assay, and changes in gene expression of ER stress markers were evaluated using RT-qPCR. MTT results revealed that 1 mM ketamine decreased cell viability in striatal cells after 24 h of treatment. Gene expression studies complemented these findings such that ketamine upregulated pro-apoptotic ER stress markers, including X-box binding protein 1 (XBP1), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP) and downregulated pro-survival ER stress proteins such as GRP78, MANF and CDNF. Ketamine activated all three stress sensing pathways including PERK, IRE1, and ATF6. Taken together, our results show that ketamine-induced neurotoxicity is mediated through an ER stress-dependent apoptotic pathway.

Identification of an endoplasmic reticulum stress-related signature associated with clinical prognosis and immune therapy in glioma

Background

Glioma is the most common brain tumor in adults and is characterized by a short survival time and high resistance to chemotherapy. It is imperative to determine the prognosis and therapy-related targets for glioma. Endoplasmic reticulum stress (ERS), as an adaptive protective mechanism, indicates the unfolded protein response (UPR) to determine cell survival and affects chemotherapy sensitivity, which is related to the prognosis of glioma.

Methods

Our research used the TCGA database as the training group and the CGGA database as the testing group. Lasso regression and Cox analysis were performed to construct an ERS signature-based risk score model in glioma. Three methods (time-dependent receiver operating characteristic analysis and multivariate and univariate Cox regression analysis) were applied to assess the independent prognostic effect of texture parameters. Consensus clustering was used to classify the two clusters. In addition, functional and immune analyses were performed to assess the malignant process and immune microenvironment. Immunotherapy and anticancer drug response prediction were adopted to evaluate immune checkpoint and chemotherapy sensitivity.

Results

The results revealed that the 7-gene signature strongly predicts glioma prognosis. The two clusters have markedly distinct molecular and prognostic features. The validation group result revealed that the signature has exceptional repeatability and certainty. Functional analysis showed that the ERS-related gene signature was closely associated with the malignant process and prognosis of tumors. Immune analysis indicated that the ERS-related gene signature is strongly related to immune infiltration. Immunotherapy and anticancer drug response prediction indicated that the ERS-related gene signature is positively correlated with immune checkpoint and chemotherapy sensitivity.

Conclusions

Collectively, the ERS-related risk model can provide a novel signature to predict glioma prognosis and treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02709-y.

[Influence of N-alkynylaminosteroids on mitochondria function and autophagy in glioma cells]

In this work we examined the synthesized N-alkynyl-17-aminosteroids and N-alkynyl-20-aminosteroids (based on dehydroepiandrosterone and pregnenolone, respectively) for their effect on C6 rat glioma cell functions. At 10 μM, the compounds had an insignificant effect on C6 glioma mitochondrial membrane potential, but increased cell autophagy by 70-90%, comparable to the known autophagy inducer dexamethasone. Docking simulations predict a potential high-affinity interaction between N-alkynylaminosteroids and Keap1 and the Hedgehog pathway protein, Smoothened, which are involved in autophagy regulation. The possible mechanisms of observed processes are discussed.

The Clinical Value of High-Quality Nursing in Concurrent Radiotherapy and Chemotherapy after Glioma Surgery and Its Influence on the Stress Indicators Cor, ACTH, and CRP

Objective

The purpose of this study is to explore the clinical value of high-quality nursing in concurrent radiotherapy and chemotherapy after glioma surgery and its influence on the stress indicators such as cortisol (Cor), adrenocorticotrophic hormone (ACTH), and C-reactive protein (CRP).

Methods

A total of 94 glioma patients diagnosed and treated in our hospital were randomly divided into a research group and a control group, with 47 cases in each group. Both groups of patients were given concurrent radiotherapy and chemotherapy. On this basis, patients in the control group were given basic care, while patients in the research group were given a combination of basic care and high-quality care. The nursing satisfaction and adverse reactions of the two groups were compared. The pain degree and the levels of stress indicators Cor, ACTH, and CRP at different time points were compared between the two groups. The sleep quality, bad mood, and quality of life before and after nursing were compared between the two groups.

Results

After nursing, the nursing satisfaction of the research group (95.74%) was higher than that of the control group (80.85%), and the difference between the two groups was statistically significant (X² = 11.678, P < 0.05). There was no significant difference between patients in the Visual Analogue Scale (VAS) score and the levels of stress indicators Cor, ACTH, and CRP at the T1 time point between the two groups (P > 0.05). With the passage of time, the levels of Cor and ACTH of the two groups showed an upward trend. At T4, the increased levels of Cor and ACTH in the research group were less than those in the control group, and the difference was statistically significant (P < 0.05). The VAS scores and CRP levels of the two groups showed an upward trend at T1 and T2 and a downward trend at T3 and T4. And, at T4, the decrease in CRP level of the research group was greater than that in the control group, and the difference was statistically significant (P < 0.05). Before nursing, there was no statistically significant difference between two groups of patients in the time to fall asleep, sleep time, number of awakenings, SAS score, self-rating depression scale (SDS) score, quality of life index scores, and total scores (P > 0.05). After nursing, the time to fall asleep and the number of awakenings in the two groups of patients showed an upward trend, and the increase in the control group was higher (P < 0.05). The sleep time of the two groups showed a downward trend, and the degree of decline in the control group was higher (P < 0.05). After nursing, the SAS score and SDS score of the two groups of patients decreased (^∗P < 0.05), and the decrease in the research group was more obvious (^#P < 0.05). After nursing, the scores of all indicators of the quality of life and the total score of the two groups increased and the score of the research group increased more significantly (P < 0.05). After nursing, the control group had 5 cases of gastrointestinal reactions, 7 cases of bone marrow suppression, 6 cases of leukopenia, 6 cases of thrombocytopenia, and 10 cases of dizziness and nausea. In the research group, there were 1 case of gastrointestinal reaction, 2 cases of bone marrow suppression, 1 case of leukopenia, 1 case of thrombocytopenia, and 2 cases of dizziness and nausea. The difference between the two groups was statistically significant (P < 0.05).

Conclusion

Glioma patients are given high-quality care during the course of concurrent radiotherapy and chemotherapy, which can reduce the pain and bad mood of the patient, reduce the stress response of the patient, and improve the quality of sleep and the quality of life of the patient, thereby improving nursing satisfaction and patients compliance, reducing adverse reactions, and having a good prognosis.

ERN1 knockdown modifies the impact of glucose and glutamine deprivations on the expression of EDN1 and its receptors in glioma cells

Objective. The aim of the present investigation was to study the impact of glucose and gluta-mine deprivations on the expression of genes encoding EDN1 (endothelin-1), its cognate receptors (EDNRA and EDNRB), and ECE1 (endothelin converting enzyme 1) in U87 glioma cells in response to knockdown of ERN1 (endoplasmic reticulum to nucleus signaling 1), a major signaling pathway of endoplasmic reticulum stress, for evaluation of their possible implication in the control of glioma growth through ERN1 and nutrient limitations. Methods. The expression level of EDN1, its receptors and converting enzyme 1 in control U87 glioma cells and cells with knockdown of ERN1 treated by glucose or glutamine deprivation by quantitative polymerase chain reaction was studied. Results. We showed that the expression level of EDN1 and ECE1 genes was significantly up-regulated in control U87 glioma cells exposure under glucose deprivation condition in comparison with the glioma cells, growing in regular glucose containing medium. We also observed up-regulation of ECE1 gene expression in U87 glioma cells exposure under glutamine deprivation as well as down-regulation of the expression of EDN1 and EDNRA mRNA, being more significant for EDN1. Furthermore, the knockdown of ERN1 signaling enzyme function significantly modified the response of most studied gene expressions to glucose and glutamine deprivation conditions. Thus, the ERN1 knockdown led to a strong suppression of EDN1 gene expression under glucose deprivation, but did not change the effect of glutamine deprivation on its expression. At the same time, the knockdown of ERN1 signaling introduced the sensitivity of EDNRB gene to both glucose and glutamine deprivations as well as completely removed the impact of glucose deprivation on the expression of ECE1 gene. Conclusions. The results of this study demonstrated that the expression of endothelin-1, its receptors, and ECE1 genes is preferentially sensitive to glucose and glutamine deprivations in gene specific manner and that knockdown of ERN1 significantly modified the expression of EDN1, EDNRB, and ECE1 genes in U87 glioma cells. It is possible that the observed changes in the expression of studied genes under nutrient deprivation may contribute to the suppressive effect of ERN1 knockdown on glioma cell proliferation and invasiveness.

In vivo CRISPR screening for novel noncoding RNA functional targets in glioblastoma models

CRISPR (clustered regularly interspaced short palindromic repeat)-based genetic screens offer unbiased and powerful tools for systematic and specific evaluation of phenotypes associated with specific target genes. CRISPR screens have been utilized heavily in vitro to identify functional coding and noncoding genes in a large number of cell types, including glioblastoma (GB), though no prior study has described the evaluation of CRISPR screening in GB in vivo. Here, we describe a protocol for targeting and transcriptionally repressing GB-specific long noncoding RNAs (lncRNAs) by CRISPR interference (CRISPRi) system in vivo, with tumor growth in the mouse cerebral cortex. Given the target-specific parameters of each individual screen, we list general steps involved in transducing guide RNA libraries into GB tumor lines, maintaining sufficient coverage, as well as cortically injecting and subsequently isolating transduced screen tumor cell populations for analysis. Finally, in order to demonstrate the use of this technique to discern an essential lncRNA, HOTAIR, from a nonessential lncRNA, we injected a 1:1 (HOTAIR:control nonessential lncRNA knockdown) mixture of fluorescently tagged U87 GB cells into the cortex of eight mice, evaluating selective depletion of HOTAIR-tagged cells at 2 weeks of growth. Fluorescently tagged populations were analyzed via flow cytometry for hiBFP (control knockdown) and green fluorescent protein (HOTAIR knockdown), revealing 17% (p = 0.007) decrease in fluorescence associated with HOTAIR knockdown relative to control. The described in vivo CRISPR screening methodology thus appears to be an effective option for identifying noncoding (and coding) genes affecting GB growth within the mouse cortex.