The Delicate Equilibrium between Oxidants and Antioxidants in Brain Glioma

Antitumoral Activity of Cecropia Pachystachya Leaves Extract in Vitro and in Vivo Model of Rat Glioma: Brain and Blood Effects

The aim of this study was to investigate the antiglioma effect of Cecropia pachystachya Trécul (CEC) leaves extract against C6 and U87 glioblastoma (GB) cells and in a rat preclinical GB model. The CEC extract reduced in vitro cell viability and biomass. In vivo, the extract decreased the tumor volume approximately 62%, without inducing systemic toxicity. The deficit in locomotion and memory and an anxiolytic-like behaviors induced in the GB model were minimized by CEC. The extract decreased the levels of reactive oxygen species, nitrites and thiobarbituric acid reactive substances and increased the activity of antioxidant enzymes in platelets, sera and brains of GB animals. The activity of NTPDases, 5'-nucleotidase and adenosine deaminase (ADA) was evaluated in lymphocytes, platelets and serum. In platelets, ATP and AMP hydrolysis was reduced and hydrolysis of ADP and the activity of ADA were increased in the control, while in CEC-treated animals no alteration in the hydrolysis of ADP was detected. In serum, the reduction in ATP hydrolysis was reversed by CEC. In lymphocytes, the increase in the hydrolysis of ATP, ADP and in the activity of ADA observed in GB model was altered by CEC administration. The observed increase in IL-6 and decrease in IL-10 levels in the serum of GB animals was reversed by CEC. These results demonstrate that CEC extract is a potential complementary treatment to GB, decreasing the tumor size, while modulating aspects of redox and purinergic systems.

Inside the genome: understanding genetic influences on oxidative stress

Genetics is a key factor that governs the susceptibility to oxidative stress. In the body, oxidative burden is regulated by the balance between the prooxidant genes that orchestrate processes that produce oxidant species, while the antioxidant genes aid those involved in scavenging these species. Together, the two components aid in maintaining the oxidative balance in the body. Genetic variations can influence the expression and activity of the encoded proteins which can then affect their efficiency in regulating redox processes, thereby increasing the risk of oxidative stress. This review studies single nucleotide polymorphisms (SNPs) that bear relevance to oxidative stress by exploring the variations in the prooxidant genes, such as XDH, CYBA, CYP1A1, PTGS2, NOS, and MAO and antioxidant genes including SOD, CAT, GPX, GSS, GLUL, GSR, GSTM1, GSTM5, GSTP1, TXN and HMOX1. Early identification of individuals at the increased risk of oxidative stress is possible from the assessment of sequence of these genes. Integrating genetic insights into oxidative stress management measures can pave the way for personalized medicine that tailors' healthcare approaches to individual genetic profiles. Effective genetic assessment along with routine quantification of biological markers can improve and monitor treatment strategies, enhancing mitigation approaches that maintain cellular health and promote longevity.

Effect of Rosmarinic Acid on Cell Proliferation, Oxidative Stress, and Apoptosis Pathways in an Animal Model of Induced Glioblastoma Multiforme

BACKGROUND

In brain tumors, the complexity of the pathophysiological processes such as oxidative stress, cell proliferation, angiogenesis, and apoptosis have seriously challenged the definitive treatment. Rosmarinic acid (RA), as a polyphenolic compound, has been found to prevent tumor progression in some aggressive cancers. This study was designed to evaluate the anticancer effects of RA on brain tumors.

METHOD

Rats were divided into six groups. Implantation of C6 glioma cells was carried out in the caudate nucleus of the right hemisphere. RA at doses of 5, 10, and 20 mg/kg (i.p.) was administered to the treatment groups for seven days. Tumor volume (by MRI imaging), locomotor ability, survival time, histological alterations (by H & E staining), expression of p53 and p21 mRNAs (by RT-PCR), activities of antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT] by assay kits), expression of caspase-3 and VEGF (by immunohistochemical analysis), and TUNEL-positive cells (by tunnel staining) were analyzed.

RESULTS

The results indicated that the RA at a dose of 20 mg/kg reduced the tumor volume, prolonged survival time, increased p53 and p21 mRNAs, attenuated SOD and CAT activities in tumor tissue, elevated caspase-3, and increased the number of TUNEL-positive cells. Furthermore, histological analysis revealed less invasion of tumor cells into the normal parenchyma in rats treated with RA (20 mg/kg).

CONCLUSION

These findings provide evidence that the ability of RA to reduce tumor volume could be related to factors that modulate oxidative stress (SOD and CAT enzymes), cell proliferation (p53 and p21), and apoptosis (caspase-3).

ANKZF1 knockdown inhibits glioblastoma progression by promoting intramitochondrial protein aggregation through mitoRQC

Protein homeostasis is fundamental to the development of tumors. Ribosome-associated quality-control (RQC) is able to add alanine and threonine to the stagnant polypeptide chain C-terminal (CAT-tail) when protein translation is hindered, while Ankyrin repeat and zinc-finger domain-containing-protein 1 (ANKZF1) can counteract the formation of the CAT-tail, preventing the aggregation of polypeptide chains. In particular, ANKZF1 plays an important role in maintaining mitochondrial protein homeostasis by mitochondrial RQC (mitoRQC) after translation stagnation of precursor proteins targeting mitochondria. However, the role of ANKZF1 in glioblastoma is unclear. Therefore, the current study was aimed to investigate the effects of ANKZF1 in glioblastoma cells and a nude mouse glioblastoma xenograft model. Here, we reported that knockdown of ANKZF1 in glioblastoma cells resulted in the accumulation of CAT-tail in mitochondria, leading to the activated mitochondrial unfolded protein response (UPRmt) and inhibits glioblastoma malignant progression. Excessive CAT-tail sequestered mitochondrial chaperones HSP60, mtHSP70 and proteases LONP1 as well as mitochondrial respiratory chain subunits ND1, Cytb, mtCO2 and ATP6, leading to mitochondrial oxidative phosphorylation dysfunction, membrane potential impairment, and mitochondrial apoptotic pathway activation. Our study highlights ANKZF1 as a valuable target for glioblastoma intervention and provides an innovative insight for the treatment of glioblastoma through the regulating of mitochondrial protein homeostasis.

Proteomics of tumor and serum samples from isocitrate dehydrogenase-wildtype glioblastoma patients: is the detoxification of reactive oxygen species associated with shorter survival?

Proteomics has been little used for the identification of novel prognostic and/or therapeutic markers in isocitrate dehydrogenase (IDH)-wildtype glioblastoma (GB). In this study, we analyzed 50 tumor and 30 serum samples from short- and long-term survivors of IDH-wildtype GB (STS and LTS, respectively) by data-independent acquisition mass spectrometry (DIA-MS)-based proteomics, with the aim of identifying such markers. DIA-MS identified 5422 and 826 normalized proteins in tumor and serum samples, respectively, with only three tumor proteins and 26 serum proteins displaying significant differential expression between the STS and LTS groups. These dysregulated proteins were principally associated with the detoxification of reactive oxygen species (ROS). In particular, GB patients in the STS group had high serum levels of malate dehydrogenase 1 (MDH1) and ribonuclease inhibitor 1 (RNH1) and low tumor levels of fatty acid-binding protein 7 (FABP7), which may have enabled them to maintain low ROS levels, counteracting the effects of the first-line treatment with radiotherapy plus concomitant and adjuvant temozolomide. A blood score built on the levels of MDH1 and RNH1 expression was found to be an independent prognostic factor for survival based on the serum proteome data for a cohort of 96 IDH-wildtype GB patients. This study highlights the utility of circulating MDH1 and RNH1 biomarkers for determining the prognosis of patients with IDH-wildtype GB. Furthermore, the pathways driven by these biomarkers, and the tumor FABP7 pathway, may constitute promising therapeutic targets for blocking ROS detoxification to overcome resistance to chemoradiotherapy in potential GB STS.

Exposure to the plasticizer dibutyl phthalate causes oxidative stress and neurotoxicity in brain tissue

The phthalate ester, dibutyl phthalate (DBP), is one of the endocrine-disrupting chemicals detected in various aquatic environments. Previous research has found multiple toxic effects of DBP in aquatic organisms; however, the neurotoxic effects of the compound are surprisingly scanty. The purpose of this study was aimed to evaluate the role of oxidative stress in the induction of neurotoxicity in the brain tissue of the fish Pseudetroplus maculatus. The fish were exposed to the sublethal concentration of DBP (200 µg L-1) for 1, 4, 7, and 15 days along with control and vehicle control groups. The induction of oxidative stress in the brain subcellular fractions was proved by alterations in the activities of superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase along with the reduction in the total antioxidant capacity. Meanwhile, the levels of hydrogen peroxide and lipid peroxidation were increased. Neurotransmitters such as acetylcholine, dopamine, adrenaline, noradrenaline, and serotonin were altered in all subcellular fractions suggesting the disruption of the neurotransmitter system in the fish brain. These results indicate that DBP induces oxidative stress, which correlates with neurotoxicity in Pseudetroplus maculatus brain tissue.

ROS regulation in gliomas: implications for treatment strategies

Gliomas are one of the most common primary malignant tumours of the central nervous system (CNS), of which glioblastomas (GBMs) are the most common and destructive type. The glioma tumour microenvironment (TME) has unique characteristics, such as hypoxia, the blood-brain barrier (BBB), reactive oxygen species (ROS) and tumour neovascularization. Therefore, the traditional treatment effect is limited. As cellular oxidative metabolites, ROS not only promote the occurrence and development of gliomas but also affect immune cells in the immune microenvironment. In contrast, either too high or too low ROS levels are detrimental to the survival of glioma cells, which indicates the threshold of ROS. Therefore, an in-depth understanding of the mechanisms of ROS production and scavenging, the threshold of ROS, and the role of ROS in the glioma TME can provide new methods and strategies for glioma treatment. Current methods to increase ROS include photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), etc., and methods to eliminate ROS include the ingestion of antioxidants. Increasing/scavenging ROS is potentially applicable treatment, and further studies will help to provide more effective strategies for glioma treatment.

Prognosis prediction based on methionine metabolism genes signature in gliomas

BACKGROUND

Glioma cells have increased intake and metabolism of methionine, which can be monitored with 11 C-L-methionine. However, a short half-life of 11 C (~ 20 min) limits its application in clinical practice. It is necessary to develop a methionine metabolism genes-based prediction model for a more convenient prediction of glioma survival.

METHODS

We evaluated the patterns of 29 methionine metabolism genes in glioma from the Cancer Genome Atlas (TCGA). A risk model was established using Lasso regression analysis and Cox regression. The reliability of the prognostic model was validated in derivation and validation cohorts (Chinese Glioma Genome Atlas; CGGA). GO, KEGG, GSEA and ESTIMATE analyses were performed for biological functions and immune characterization.

RESULTS

Our results showed that a majority of the methionine metabolism genes (25 genes) were involved in the overall survival of glioma (logrank p and Cox p < 0.05). A 7-methionine metabolism prognostic signature was significantly related to a poor clinical prognosis and overall survival of glioma patients (C-index = 0.83). Functional analysis revealed that the risk model was correlated with immune responses and with epithelial-mesenchymal transition. Furthermore, the nomogram integrating the signature of methionine metabolism genes manifested a strong prognostic ability in the training and validation groups.

CONCLUSIONS

The current model had the potential to improve the understanding of methionine metabolism in gliomas and contributed to the development of precise treatment for glioma patients, showing a promising application in clinical practice.

Knockdown of HNRNPM inhibits the progression of glioma through inducing ferroptosis

PURPOSE

Ferroptosis acts as an important regulator in diverse human tumors, including the glioma. This study aimed to screen potential ferroptosis-related genes involved in the progression of glioma.

MATERIALS AND METHODS

Differently expressed genes (DEGs) were screened based on GSE31262 and GSE12657 datasets, and ferroptosis-related genes were separated. Among the important hub genes in the protein-protein interaction networks, HNRNPM was selected as a research target. Following the knockdown of HNRNPM, the viability, migration, and invasion were detected by CCK8, wound healing, and transwell assays, respectively. The role of HNRNPM knockdown was also verified in a xenograft tumor model in mice. Immunohistochemistry detected the expression levels of HNRNPM and Ki67. Moreover, the ferroptosis was evaluated according to the levels of iron, glutathione peroxidase (GSH), and malondialdehyde (MDA), as well as the expression of PTGS2, GPX4, and FTH1.

RESULTS

Total 41 overlapping DEGs relating with ferroptosis and glioma were screened, among which 4 up-regulated hub genes (HNRNPM, HNRNPA3, RUVBL1, and SNRPPF) were determined. The up-regulation of HNRNPM presented a certain predictive value for glioma. In addition, knockdown of HNRNPM inhibited the viability, migration, and invasion of glioma cells in vitro, and also the tumor growth in mice. Notably, knockdown of HNRNPM enhanced the ferroptosis in glioma cells. Furthermore, HNRNPM was positively associated with SMARCA4 in glioma.

CONCLUSIONS

Knockdown of HNRNPM inhibits the progression of glioma via inducing ferroptosis. HNRNPM is a promising molecular target for the treatment of glioma via inducing ferroptosis. We provided new insights of glioma progression and potential therapeutic guidance.

Tumor microenvironment in a minipig model of spinal cord glioma

BACKGROUND

Spinal cord glioma (SCG) is considered an orphan disease that lacks effective treatment options with margins that are surgically inaccessible and an overall paucity of literature on the topic. The tumor microenvironment is a critical factor to consider in treatment and modeling design, especially with respect to the unresectable tumor edge. Recently, our group developed a high-grade spinal cord glioma (SCG) model in Göttingen minipigs.

METHODS

Immunofluorescence and ELISA were performed to explore the microenvironmental features and inflammation cytokines in this minipig SCG model. Protein carbonyl assay and GSH/GSSG assay were analyzed in the core and edge lesions in the minipig SCG model. The primary core and edge cells proliferation rate were shown in vitro, and the xenograft model in vivo.

RESULTS

We identified an elevated Ki-67 proliferative index, vascular and pericyte markers, CD31 and desmin in the tumor edge as compared to the tumor core. In addition, we found that the tumor edge demonstrated increased pro-inflammatory and gliomagenic cytokines including TNF-α, IL-1β, and IL-6. Furthermore, the mediation of oxidative stress is upregulated in the tumor edge. Hypoxic markers had statistically significant increased staining in the tumor core, but were notably still present in the tumor edge. The edge cells cultures derived from SCG biopsy also demonstrated an increased proliferative rate compared to core cell cultures in a xenotransplantation model.

CONCLUSIONS

Our study demonstrates heterogeneity in microenvironmental features in our minipig model of high-grade SCG, with a phenotype at the edge showing increased oxidative stress, proliferation, inflammatory cytokines, neovascularization, and decreased but present staining for hypoxic markers. These findings support the utility of this model as a means for investigating therapeutic approaches targeting the more aggressive and surgically unresectable tumor border.

Glutathione Peroxidase gpx1 to gpx8 Genes Expression in Experimental Brain Tumors Reveals Gender-Dependent Patterns

Extensive research efforts in the field of brain tumor studies have led to the reclassification of tumors by the World Health Organization (WHO) and the identification of various molecular subtypes, aimed at enhancing diagnosis and treatment strategies. However, the quest for biomarkers that can provide a deeper understanding of tumor development mechanisms, particularly in the case of gliomas, remains imperative due to their persistently incurable nature. Oxidative stress has been widely recognized as a key mechanism contributing to the formation and progression of malignant tumors, with imbalances in antioxidant defense systems being one of the underlying causes for the excess production of reactive oxygen species (ROS) implicated in tumor initiation. In this study, we investigated the gene expression patterns of the eight known isoforms of glutathione peroxidase (GPx) in brain tissue obtained from male and female control rats, as well as rats with transplacental ethyl nitrosourea (ENU)-induced brain tumors. Employing the delta-delta Ct method for RT-PCR, we observed minimal expression levels of gpx2, gpx5, gpx6, and gpx7 in the brain tissue from the healthy control animals, while gpx3 and gpx8 exhibited moderate expression levels. Notably, gpx1 and gpx4 displayed the highest expression levels. Gender differences were not observed in the expression profiles of these isoforms in the control animals. Conversely, the tumor tissue exhibited elevated relative expression levels in all isoforms, except for gpx4, which remained unchanged, and gpx5, which exhibited alterations solely in female animals. Moreover, except for gpx1, which displayed no gender differences, the relative expression values of gpx2, gpx3, gpx6, gpx7, and gpx8 were significantly higher in the male animals compared to their female counterparts. Hence, the analysis of glutathione peroxidase isoforms may serve as a valuable approach for discerning the behavior of brain tumors in clinical settings.

Bilirubin and Redox Stress in Age-Related Brain Diseases

Cellular redox status has a crucial role in brain physiology, as well as in pathologic conditions. Physiologic senescence, by dysregulating cellular redox homeostasis and decreasing antioxidant defenses, enhances the central nervous system's susceptibility to diseases. The reduction of free radical accumulation through lifestyle changes, and the supplementation of antioxidants as a prophylactic and therapeutic approach to increase brain health, are strongly suggested. Bilirubin is a powerful endogenous antioxidant, with more and more recognized roles as a biomarker of disease resistance, a predictor of all-cause mortality, and a molecule that may promote health in adults. The alteration of the expression and activity of the enzymes involved in bilirubin production, as well as an altered blood bilirubin level, are often reported in neurologic conditions and neurodegenerative diseases (together denoted NCDs) in aging. These changes may predict or contribute both positively and negatively to the diseases. Understanding the role of bilirubin in the onset and progression of NCDs will be functional to consider the benefits vs. the drawbacks and to hypothesize the best strategies for its manipulation for therapeutic purposes.

Gender Differences in Oxidative Stress in Relation to Cancer Susceptibility and Survival

Genetic, developmental, biochemical, and environmental variables interact intricately to produce sex differences. The significance of sex differences in cancer susceptibility is being clarified by numerous studies. Epidemiological research and cancer registries have revealed over the past few years that there are definite sex variations in cancer incidence, progression, and survival. However, oxidative stress and mitochondrial dysfunction also have a significant impact on the response to treatment of neoplastic diseases. Young women may be more protected from cancer than men because most of the proteins implicated in the regulation of redox state and mitochondrial function are under the control of sexual hormones. In this review, we describe how sexual hormones control the activity of antioxidant enzymes and mitochondria, as well as how they affect several neoplastic diseases. The molecular pathways that underlie the gender-related discrepancies in cancer that have been identified may be better understood, which may lead to more effective precision medicine and vital information on treatment options for both males and females with neoplastic illnesses.

Longitudinal changes in brain metabolites in healthy controls and patients with first episode psychosis: a 7-Tesla MRS study

Seven Tesla magnetic resonance spectroscopy (7T MRS) offers a precise measurement of metabolic levels in the human brain via a non-invasive approach. Studying longitudinal changes in brain metabolites could help evaluate the characteristics of disease over time. This approach may also shed light on how the age of study participants and duration of illness may influence these metabolites. This study used 7T MRS to investigate longitudinal patterns of brain metabolites in young adulthood in both healthy controls and patients. A four-year longitudinal cohort with 38 patients with first episode psychosis (onset within 2 years) and 48 healthy controls was used to examine 10 brain metabolites in 5 brain regions associated with the pathophysiology of psychosis in a comprehensive manner. Both patients and controls were found to have significant longitudinal reductions in glutamate in the anterior cingulate cortex (ACC). Only patients were found to have a significant decrease over time in γ-aminobutyric acid, N-acetyl aspartate, myo-inositol, total choline, and total creatine in the ACC. Together we highlight the ACC with dynamic changes in several metabolites in early-stage psychosis, in contrast to the other 4 brain regions that also are known to play roles in psychosis. Meanwhile, glutathione was uniquely found to have a near zero annual percentage change in both patients and controls in all 5 brain regions during a four-year follow-up in young adulthood. Given that a reduction of the glutathione in the ACC has been reported as a feature of treatment-refractory psychosis, this observation further supports the potential of glutathione as a biomarker for this subset of patients with psychosis.

Food processing and risk of central nervous system tumours: A preliminary case-control analysis from the MEditerranean DIet in relation to CancEr of brAin (MEDICEA) study

BACKGROUND

The relationship between diet and central nervous system (CNS) tumours was almost exclusively focused on food composition. We evaluated the relationship of different degrees of food processing with risk of CNS tumours.

METHODS

The study sample included 44 CNS tumours cases (20 non-malignant and 24 malignant) recruited from the Neurosurgery Department at the IRCCS Neuromed (Italy), and 88 controls matched 1:2 for sex and age± 10 years, identified from the Moli-sani Study. Dietary intake was assessed using a 188-item FFQ. Food items were grouped according to the NOVA classification on the basis of processing as: (1) unprocessed/minimally processed foods; (2) processed culinary ingredients; (3) processed foods; and (4) ultra-processed food (UPF). Conditional logistic regression models were used to estimate odds ratio (OR) and 95% confidence intervals (95%CI) of dietary contributions from each NOVA group (as weight ratio on the total food eaten) and adjusting for potential confounders.

RESULTS

In a multivariable conditional to match logistic regression analysis also controlled for overall diet quality, 1% increment in UPF intake was associated with higher odds of all CNS tumours (OR = 1.06; 1.01-1.13), particularly of malignant CNS tumours (OR = 1.11; 1.02-1.22), while no association with non-malignant CNS tumours was found (OR = 1.06; 0.99-1.15). In contrast, only processed food was inversely associated with risk of both CNS tumours overall (OR = 0.94; 0.90-0.98) and of malignant CNS tumours (OR = 0.90; 0.83-0.96).

CONCLUSION

Increasing UPF intake was associated with higher risk of CNS tumours, especially malignant ones, independently of the overall diet quality, while only processed food (but not UPF) was inversely related to the risk of this disease.

Impact of gallic acid on tumor suppression: Modulation of redox homeostasis and purinergic response in in vitro and a preclinical glioblastoma model

Glioblastoma (GBM) is the deadliest primary brain tumor in adults due to the high rate of relapse with current treatment. Therefore, the search for therapeutic alternatives is urgent. Gallic acid (GA), a potent natural antioxidant, has antitumor and modulatory actions on purinergic signaling. In this study, we investigated the cytotoxic effects of GA on the rat GBM (C6) cell line and on astrocyte culture and analyzed its role in regulating oxidative stress and purinergic enzymes involved in GBM proliferation. Cells were exposed to GA from 50 to 400 µM for 24 and/or 48 h. Next, the effect of GA was evaluated in the preclinical model of GBM. Wistar rats were treated with 50 or 100 mg/kg of GA for 15 days, and cerebral and systemic redox status and degradation of adenine nucleotides and nucleosides in circulating platelets, lymphocytes, and serum were evaluated. Our results demonstrated that GA has selective anti-glioma activity in vitro, without inducing cytotoxicity in astrocyte. Furthermore, GA prevented oxidative stress and changes in the hydrolysis of nucleotides in GBM cells. The anti-glioma effect was also observed in vivo, as GA reduced tumor volume by 90%. Interestingly, GA decreased the oxidative damage induced by a tumor in the brain, serum, and platelets, and, also prevented changes in the degradation of nucleotides and nucleosides in lymphocytes, platelets, and serum. These results indicate, for the first time, the therapeutic potential of GA in a preclinical model of GBM, whose effects may be related to its role in redox and purinergic modulation.

GSK343, an Inhibitor of Enhancer of Zeste Homolog 2, Reduces Glioblastoma Progression through Inflammatory Process Modulation: Focus on Canonical and Non-Canonical NF-κB/IκBα Pathways

Glioblastoma (GB) is a tumor of the central nervous system characterized by high proliferation and invasiveness. The standard treatment for GB includes radiotherapy and chemotherapy; however, new therapies are needed. Particular attention was given to the role of histone methyltransferase enhancer of zeste-homolog-2 (EZH2) in GB. Recently, several EZH2-inhibitors have been developed, particularly GSK343 is well-known to regulate apoptosis and autophagy processes; however, its abilities to modulate canonical/non-canonical NF-κB/IκBα pathways or an immune response in GB have not yet been investigated. Therefore, this study investigated for the first time the effect of GSK343 on canonical/non-canonical NF-κB/IκBα pathways and the immune response, by an in vitro, in vivo and ex vivo model of GB. In vitro results demonstrated that GSK343 treatments 1, 10 and 25 μM significantly reduced GB cell viability, showing the modulation of canonical/non-canonical NF-κB/IκBα pathway activation. In vivo GSK343 reduced subcutaneous tumor mass, regulating canonical/non-canonical NF-κB/IκBα pathway activation and the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Ex vivo results confirmed the anti-proliferative effect of GSK343 and also demonstrated its ability to regulate immune response through CXCL9, CXCL10 and CXCL11 expression in GB. Thus, GSK343 could represent a therapeutic strategy to counteract GB progression, thanks to its ability to modulate canonical/non-canonical NF-κB/IκBα pathways and immune response.

Injury programs shape glioblastoma

Glioblastoma is the most common and aggressive primary brain cancer in adults and is almost universally fatal due to its stark therapeutic resistance. During the past decade, although survival has not substantially improved, major advances have been made in our understanding of the underlying biology. It has become clear that these devastating tumors recapitulate features of neurodevelopmental hierarchies which are influenced by the microenvironment. Emerging evidence also highlights a prominent role for injury responses in steering cellular phenotypes and contributing to tumor heterogeneity. This review highlights how the interplay between injury and neurodevelopmental programs impacts on tumor growth, invasion, and treatment resistance, and discusses potential therapeutic considerations in view of these findings.

Antioxidants in brain tumors: current therapeutic significance and future prospects

Brain cancer is regarded among the deadliest forms of cancer worldwide. The distinct tumor microenvironment and inherent characteristics of brain tumor cells virtually render them resistant to the majority of conventional and advanced therapies. Oxidative stress (OS) is a key disruptor of normal brain homeostasis and is involved in carcinogenesis of different forms of brain cancers. Thus, antioxidants may inhibit tumorigenesis by preventing OS induced by various oncogenic factors. Antioxidants are hypothesized to inhibit cancer initiation by endorsing DNA repair and suppressing cancer progression by creating an energy crisis for preneoplastic cells, resulting in antiproliferative effects. These effects are referred to as chemopreventive effects mediated by an antioxidant mechanism. In addition, antioxidants minimize chemotherapy-induced nonspecific organ toxicity and prolong survival. Antioxidants also support the prooxidant chemistry that demonstrate chemotherapeutic potential, particularly at high or pharmacological doses and trigger OS by promoting free radical production, which is essential for activating cell death pathways. A growing body of evidence also revealed the roles of exogenous antioxidants as adjuvants and their ability to reverse chemoresistance. In this review, we explain the influences of different exogenous and endogenous antioxidants on brain cancers with reference to their chemopreventive and chemotherapeutic roles. The role of antioxidants on metabolic reprogramming and their influence on downstream signaling events induced by tumor suppressor gene mutations are critically discussed. Finally, the review hypothesized that both pro- and antioxidant roles are involved in the anticancer mechanisms of the antioxidant molecules by killing neoplastic cells and inhibiting tumor recurrence followed by conventional cancer treatments. The requirements of pro- and antioxidant effects of exogenous antioxidants in brain tumor treatment under different conditions are critically discussed along with the reasons behind the conflicting outcomes in different reports. Finally, we also mention the influencing factors that regulate the pharmacology of the exogenous antioxidants in brain cancer treatment. In conclusion, to achieve consistent clinical outcomes with antioxidant treatments in brain cancers, rigorous mechanistic studies are required with respect to the types, forms, and stages of brain tumors. The concomitant treatment regimens also need adequate consideration.

Combination therapy with interferon-gamma as a potential therapeutic medicine in rat's glioblastoma: A multi-mechanism evaluation

BACKGROUND

This study assessed the effects of single or combined administration of temozolomide (TMZ) and interferon-gamma (IFN-ᵞ) on anxiety-like behaviors, balance disorders, learning and memory, TNF-α, IL-10, some oxidant and antioxidants factors with investigating the toll-like receptor-4 (TLR4) and p-CREB signaling pathway in C6-induced glioblastoma of rats.

METHODS

40 male Sprague-Dawley rats bearing intra-caudate nucleus (CN) culture medium or C6 inoculation were randomly divided into five groups as follows: Sham, Tumor, TMZ, IFN-ᵞ and a TMZ + IFN-ᵞ combination. The open-field test (OFT), elevated plus maze (EPM), rotarod, and passive avoidance test (PAT) were done on days 14-17. On day 17 after tumor implantation, brain tissues were extracted for histopathological evaluation. TNF-α, IL-10, SOD, GPX, TAC, MDA, the protein level of TLR4 and p-CREB was measured.

RESULTS

Combination therapy inhibited the growth of the tumor. Treatment groups alleviated tumor-induced anxiety-like behaviors and improved imbalance and memory impairment. SOD, GPX, and TAC decreased in the tumor group. The combination group augmented GPX and TAC. MDA decreased in treatment groups. TMZ, IFN-ᵞ reduced tumor-increased TNF-α and IL-10 level. The combination group declined TNF-α level in serum and IL-10 level in serum and brain. Glioblastoma induced significant upregulation of TLR4 and p-CREB in the brain which inhibited by IFN-ᵞ and TMZ+ IFN-ᵞ.

CONCLUSION

The beneficial effects of TMZ, IFN-ᵞ, and TMZ+ IFN-ᵞ on neurocognitive functioning of rats with C6-induced glioblastoma may be mediated via modulating oxidative stress, reduced cytokines, and the downregulation of expression of TLR4 and p-CREB. Combination treatment appears to be more effective than single treatment.

Curcumin piperidone derivatives induce anti-proliferative and anti-migratory effects in LN-18 human glioblastoma cells

Curcumin has demonstrated potential cytotoxicity across various cell lines despite its poor bioavailability and rapid metabolism. Therefore, our group have synthesized curcuminoid analogues with piperidone derivatives, FLDP-5 and FLDP-8 to overcome these limitations. In this study, the analogues were assessed on LN-18 human glioblastoma cells in comparison to curcumin. Results from cytotoxicity assessment showed that FLDP-5 and FLDP-8 curcuminoid analogues caused death in LN-18 cells in a concentration-dependent manner after 24-h treatment with much lower IC50 values of 2.5 µM and 4 µM respectively, which were more potent compared to curcumin with IC50 of 31 µM. Moreover, a significant increase (p < 0.05) in the level of superoxide anion and hydrogen peroxide upon 2-h and 6-h treatment confirmed the oxidative stress involvement in the cell death process induced by these analogues. These analogues also showed potent anti-migratory effects through inhibition of LN-18 cells' migration and invasion. In addition, cell cycle analysis showed that these analogues are capable of inducing significant (p < 0.05) S-phase cell cycle arrest during the 24-h treatment as compared to untreated, which explained the reduced proliferation indicated by MTT assay. In conclusion, these curcuminoid analogues exhibit potent anti-cancer effects with anti-proliferative and anti-migratory properties towards LN-18 cells as compared to curcumin.

Physical Training Protects Against Brain Toxicity in Mice Exposed to an Experimental Model of Glioblastoma

Glioma 261 (Gl261) cell-mediated neurotoxicity has been reported in previous studies examining glioblastoma (GBM), and the effects of physical exercise (PE) on this neurotoxicity have been poorly investigated. This study aimed to evaluate the effects of a PE program in animals with experimental GBM. Male C57BL/6J mice were randomized into sham or GBM groups and subjected to a PE program for four weeks. Gl261 cells were administered into the intraventricular region at 48 h after the last exercise session. Body weight, water and feed consumption, and behavior were all evaluated for 21 days followed by euthanasia. The right parietal lobe was removed for the analysis of glial fibrillary acidic protein (GFAP), epidermal growth factor receptor (EGFR), vimentin, C-myc, nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), hydrogen peroxide, the glutathione system, and oxidative damage to proteins. The results revealed changes in the behavioral patterns of the trained animals, and no anatomopathological changes were observed in response to PE training. In contrast, animals with GBM subjected to PE exhibited lower immunoexpression of c-MYC, vimentin, and GFAP. Although experimental GBM altered the redox profile and inflammatory mediators, no significant alterations were observed after PE. In conclusion, our data provide consistent evidence of the relationship between PE and the improvement of tumorigenic parameters against the neurotoxicity of GL261 cells.

Clinical Observation of Patients Undergoing Glioma Surgery under Propofol and Sevoflurane Anesthesia: A Retrospective Study

Objective

To observe the effects of propofol and sevoflurane anesthesia on patients undergoing glioma surgery.

Methods

192 patients with gliomas treated in our hospital from January 2016 to January 2021 were selected. All patients were randomly divided into observation group and control group. The observation group was given sevoflurane and the control group was given propofol. The clinical effects of the two groups were observed.

Results

Comparison of clinical indexes related to intraoperative conditions between the two groups revealed that the time of anesthesia and extubation after operation in the observation group were shorter than those in the control group, and the difference was statistically significant (P < 0.05). The amount of intraoperative bleeding in the observation group was less than that in the control group, and the difference was statistically significant (P < 0.05). There was no significant difference in intracranial operation time, operation time, fluid volume, and urine volume between the two groups (P < 05). Comparing the recovery time of anesthesia between the two groups, the recovery time of orientation and the time of eye-opening in the observation group were significantly shorter than those in the control group (P < 0.05). Comparing the consciousness and cognitive function of the two groups, the OAAS score of the observation group after extubation, before leaving the operating room and 1 hour after extubation, was significantly higher than that of the control group (P < 0.05), and the MMSE score l h after extubation was significantly higher than that of the control group (P < 0.05). Comparing the incidence of postoperative complications between the two groups, the number of cases of restlessness, urinary infection, deep vein thrombosis, and hypertension in the observation group was lower than that in the control group, with statistical significance (P < 0.05).

Conclusion

The anesthesia time and extubation time of the sevoflurane anesthesia group were shorter than that of the propofol anesthesia group, and the orientation recovery time and eye-opening time were shortened. The OAAS score of the sevoflurane anesthesia group was higher than that of the propofol anesthesia group after extubation, before extubation, and 1 hour after extubation. The probability of postoperative complications in the sevoflurane anesthesia group was lower than that in the propofol anesthesia group. Sevoflurane anesthesia may be more suitable for surgical induction of glioma patients than propofol anesthesia.

Evaluation of total oxidative stress and antioxidant capacity of brain tumour patients attending referral hospitals in Addis Ababa, 2020: a comparative cross-sectional study

Background

The exact cause of brain tumours is still unknown, but disruptions of redox balance are thought to play a significant role in all stages of brain tumour development. However, the roles of free radical imbalance at different grades of brain tumour and degree of oxidative stress before and after surgery have not been addressed in prior studies.

Aim

A comparative cross-sectional study was conducted to assess the redox imbalance among confirmed brain tumour patients.

Methods and results

An institution-based comparative cross-sectional study was conducted on a total of 100 participants (50 brain tumour patients and 50 controls) at referral hospitals in Addis Ababa, Ethiopia. Descriptive statistics, t-test and analysis of variance (ANOVA) (post-hoc) analysis were used and statistical significance was declared at p ≤ 0.05. The serum oxidised glutathione and total oxidative stress were significantly higher in the serum of brain tumour patients (0.72 ± 0.03 μM/μg and 9.66 ± 1.76 μmol H2O2 Eq/L, respectively) compared to the control group (0.21 ± 0.07 μM/μg and 6.59 ± 0.81 μmol H2O2 Eq/L, respectively) (p ≤ 0.05). The serum total oxidant status gradually increased as the tumour grade increased, being higher in grade four (11.96 ± 0.72) and lower in grade one (8.43 ± 1.56), and the mean differences were statistically significant (p ≤ 0 05). A statistically significantly higher total antioxidant capacity (116.78 ± 5.03 Trolox Eq/L) was obtained in the post-surgery than pre-surgery level (79.65 ± 17.914 Trolox Eq/L) (p ≤ 0 05).

Conclusion

Higher oxidant and lower antioxidant levels were found in the serum of brain tumour patients than in the control group. The post-surgery oxidant level was lower than the pre-surgery state. The findings of this study could suggest that redox imbalance may have a role in the pathophysiology of brain tumours, but further experimental studies are needed.

Role of TRPM2 in brain tumours and potential as a drug target

Ion channels are ubiquitously expressed in almost all living cells, and are the third-largest category of drug targets, following enzymes and receptors. The transient receptor potential melastatin (TRPM) subfamily of ion channels are important to cell function and survival. Studies have shown upregulation of the TRPM family of ion channels in various brain tumours. Gliomas are the most prevalent form of primary malignant brain tumours with no effective treatment; thus, drug development is eagerly needed. TRPM2 is an essential ion channel for cell function and has important roles in oxidative stress and inflammation. In response to oxidative stress, ADP-ribose (ADPR) is produced, and in turn activates TRPM2 by binding to the NUDT9-H domain on the C-terminal. TRPM2 has been implicated in various cancers and is significantly upregulated in brain tumours. This article reviews the current understanding of TRPM2 in the context of brain tumours and overviews the effects of potential drug therapies targeting TRPM2 including hydrogen peroxide (H2O2), curcumin, docetaxel and selenium, paclitaxel and resveratrol, and botulinum toxin. It is long withstanding knowledge that gliomas are difficult to treat effectively, therefore investigating TRPM2 as a potential therapeutic target for brain tumours may be of considerable interest in the fields of ion channels and pharmacology.

Use of Complementary and Integrative Medicine Among Patients With Glioblastoma Multiforme Seen at a Tertiary Care Center

Background

Glioblastoma multiforme (GBM) is among the most aggressive and lethal tumors, with a median survival of 12-15 months. Many patients use complementary and integrative medicine (CIM) therapies to supplement their cancer treatment.

Objective

To determine the prevalence of CIM use and identify the most frequently used types of CIM in a cohort of patients with GBM seen at a tertiary care medical center in the United States.

Methods

An anonymous survey was mailed through the US Postal Service from August 1, 2019, through February 21, 2020, to patients with GBM.

Results

A total of 346 surveys were mailed, and 146 responses (42%) were received. The median age of respondents was 61 years (range, 52-68 years), and 85 (58%) were male. Most patients had undergone surgery (90%), chemotherapy (96%), and radiotherapy (95%). The median time from diagnosis of GBM to survey participation was 18 months (range, 12-31 months). Most respondents (81%) used some form of CIM, most frequently meditation (22%), relaxation and other stress management techniques (19%), chiropractic therapy (16%), and acupuncture (12%). Compared with men, women more commonly meditated (32% vs 16%; P = .046) and practiced yoga (20% vs 6%; P = .04). We observed age-based differences, with younger patients more commonly meditating, practicing relaxation and stress management techniques, and receiving chiropractic therapy (P < .05 for all).

Conclusions

Providers should encourage patients with GBM to discuss their interest in CIM therapies and guide them to evidence-based treatments that may help improve their quality of life.

Post-mortem Findings of Inflammatory Cells and the Association of 4-Hydroxynonenal with Systemic Vascular and Oxidative Stress in Lethal COVID-19

A recent comparison of clinical and inflammatory parameters, together with biomarkers of oxidative stress, in patients who died from aggressive COVID-19 and survivors suggested that the lipid peroxidation product 4-hydroxynonenal (4-HNE) might be detrimental in lethal SARS-CoV-2 infection. The current study further explores the involvement of inflammatory cells, systemic vascular stress, and 4-HNE in lethal COVID-19 using specific immunohistochemical analyses of the inflammatory cells within the vital organs obtained by autopsy of nine patients who died from aggressive SAR-CoV-2 infection. Besides 4-HNE, myeloperoxidase (MPO) and mitochondrial superoxide dismutase (SOD2) were analyzed alongside standard leukocyte biomarkers (CDs). All the immunohistochemical slides were simultaneously prepared for each analyzed biomarker. The results revealed abundant 4-HNE in the vital organs, but the primary origin of 4-HNE was sepsis-like vascular stress, not an oxidative burst of the inflammatory cells. In particular, inflammatory cells were often negative for 4-HNE, while blood vessels were always very strongly immunopositive, as was edematous tissue even in the absence of inflammatory cells. The most affected organs were the lungs with diffuse alveolar damage and the brain with edema and reactive astrocytes, whereas despite acute tubular necrosis, 4-HNE was not abundant in the kidneys, which had prominent SOD2. Although SOD2 in most cases gave strong immunohistochemical positivity similar to 4-HNE, unlike 4-HNE, it was always limited to the cells, as was MPO. Due to their differential expressions in blood vessels, inflammatory cells, and the kidneys, we think that SOD2 could, together with 4-HNE, be a potential link between a malfunctioning immune system, oxidative stress, and vascular stress in lethal COVID-19.

Harnessing oxidative stress for anti-glioma therapy

Glioma cells use intermediate levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) for growth and invasion, and suppressing these reactive molecules thus may compromise processes that are vital for glioma survival. Increased oxidative stress has been identified in glioma cells, in particular in glioma stem-like cells. Studies have shown that these cells harbor potent antioxidant defenses, although endogenous protection against nitrosative stress remains understudied. The enhancement of oxidative or nitrosative stress offers a potential target for triggering glioma cell death, but whether oxidative and nitrosative stresses can be combined for therapeutic effects requires further research. The optimal approach of harnessing oxidative stress for anti-glioma therapy should include the induction of free radical-induced oxidative damage and the suppression of antioxidant defense mechanisms selectively in glioma cells. However, selective induction of oxidative/nitrosative stress in glioma cells remains a therapeutic challenge, and research into selective drug delivery systems is ongoing. Because of multifactorial mechanisms of glioma growth, progression, and invasion, prospective oncological therapies may include not only therapeutic oxidative/nitrosative stress but also inhibition of oncogenic kinases, antioxidant molecules, and programmed cell death mediators.

The SP/NK1R System-Mediated ROS Generation in GBM Cells through Inhibiting Glutaredoxin Protein

Altered redox balance is among the main contributing factors developing glioblastoma multiforme (GBM), a highly aggressive grade IV brain tumor. Neuropeptide substance P (SP) plays a key role in modifying the cellular redox environment by activating the neurokinin-1 receptor (NK1R). In this study, we aimed to investigate the redox-modulating properties of both SP and a commercially available NK1R antagonist, aprepitant in GBM cells. To detect the effect of aprepitant on the viability of U87 glioblastoma cells, resazurin assay was applied. The level of intracellular ROS was assessed using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) assay. The expression of glutaredoxin, a well-known redox-active protein, was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Concurrently, the activity of glutaredoxin was also analyzed by a commercial kit (ZellBio GmbH). We found that SP increased the intracellular levels of reactive oxygen species (ROS) in U87 GBM cells, and aprepitant remarkably decreased this effect. We also explored the effects of SP/NK1R signaling on the glutaredoxin system as a major cellular redox buffer in GBM cells. SP reduced both expression and enzymatic activity of glutaredoxin, and these effects were significantly decreased by aprepitant. In conclusion, our results suggest a possible involvement of SP/NK1R signaling in GBM pathogenesis through oxidative stress and offering new insight for the application of aprepitant as a redox-modulating strategy in GBM patients.

Lichen-Derived Compounds and Extracts as Biologically Active Substances with Anticancer and Neuroprotective Properties

Lichens are a source of chemical compounds with valuable biological properties, structurally predisposed to penetration into the central nervous system (CNS). Hence, our research aimed to examine the biological potential of lipophilic extracts of Parmelia sulcata, Evernia prunastri, Cladonia uncialis, and their major secondary metabolites, in the context of searching for new therapies for CNS diseases, mainly glioblastoma multiforme (GBM). The extracts selected for the study were standardized for their content of salazinic acid, evernic acid, and (−)-usnic acid, respectively. The extracts and lichen metabolites were evaluated in terms of their anti-tumor activity, i.e., cytotoxicity against A-172 and T98G cell lines and anti-IDO1, IDO2, TDO activity, their anti-inflammatory properties exerted by anti-COX-2 and anti-hyaluronidase activity, antioxidant activity, and anti-acetylcholinesterase and anti-butyrylcholinesterase activity. The results of this study indicate that lichen-derived compounds and extracts exert significant cytotoxicity against GBM cells, inhibit the kynurenine pathway enzymes, and have anti-inflammatory properties and weak antioxidant and anti-cholinesterase properties. Moreover, evernic acid and (−)-usnic acid were shown to be able to cross the blood-brain barrier. These results demonstrate that lichen-derived extracts and compounds, especially (−)-usnic acid, can be regarded as prototypes of pharmacologically active compounds within the CNS, especially suitable for the treatment of GBM.

The Reactive Species Interactome in the Brain

Significance: Redox pioneer Helmut Sies attempted to explain reactive species' challenges faced by organelles, cells, tissues, and organs via three complementary definitions: (i) oxidative stress, that is, the disturbance in the prooxidant-antioxidant defense balance in favor of the prooxidants; (ii) oxidative eustress, the low physiological exposure to prooxidants; and (iii) oxidative distress, the supraphysiological exposure to prooxidants. Recent Advances: Identification, concentration, and interactions are the most important elements to improve our understanding of reactive species in physiology and pathology. In this context, the reactive species interactome (RSI) is a new multilevel redox regulatory system that identifies reactive species families, reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species, and it integrates their interactions with their downstream biological targets. Critical Issues: We propose a united view to fully combine reactive species identification, oxidative eustress and distress, and the RSI system. In this view, we also propose including the forgotten reactive carbonyl species, an increasingly rediscovered reactive species family related to the other reactive families, and key enzymes within the RSI. We focus on brain physiology and pathology to demonstrate why this united view should be considered. Future Directions: More studies are needed for an improved understanding of the contributions of reactive species through their identification, concentration, and interactions, including in the brain. Appreciating the RSI in its entirety should unveil new molecular players and mechanisms in physiology and pathology in the brain and elsewhere.

Maternal LiCl exposure disrupts thyroid-cerebral axis in neonatal albino rats

This work aimed to elucidate whether maternal lithium chloride (LiCl) exposure disturbs the thyroid-cerebral axis in neonatal albino rats. 50 mg of LiCl/kg b.wt. is orally given for pregnant Wistar rats from gestational day (GD) 1 to lactation day (LD) 28. The maternal administration of LiCl induced follicular dilatation and degeneration, hyperplasia, lumen obliteration and colloid vacuolation in the maternal and neonatal thyroid gland at postnatal days (PNDs) 14, 21 and 28. Neuronal degeneration (spongiform), gliosis, nuclear pyknosis, perivascular oedema, and meningeal hyperaemia were observed in the neonatal cerebral cortex of the maternal LiCl-treated group at examined PNDs. This disturbance appears to depend on intensification in the neonatal cerebral malondialdehyde (MDA), nitric oxide (NO), and hydrogen peroxide (H₂ O₂ ) levels, and attenuation in the glutathione (GSH), total thiol (t-SH), catalase (CAT), and superoxide dismutase (SOD) levels. In the neonatal cerebrum, the fold change in the relative mRNA expression of deiodinases (DII and DIII) increased significantly at PNDs 21 and 14, respectively, in the maternal LiCl-treated group. These data suggest that maternal LiCl may perturb the thyroid-cerebrum axis generating neonatal neurodevelopmental disorder.

Safety and Efficacy Assessments to Take Antioxidants in Glioblastoma Therapy: From In Vitro Experiences to Animal and Clinical Studies

Glioblastoma (GBM) is considered one of the most common malignant brain tumors, occurring as over 15% of all primary central nervous system and brain neoplasms. The unique and standard treatment option towards GBM involves the combination of surgical resection followed by radiotherapy (RT) and chemotherapy (CT). However, due to the aggressive nature and heterogeneity of GBMs, they remained difficult to treat. Recent findings from preclinical studies have revealed that disruption of the redox balance via using either oxidative or anti-oxidative agents in GBM presented an effective and promising therapeutic approach. A limited number of clinical trials substantially encouraged their concomitant use with RT or CT. Thus, treatment of GBMs may benefit from natural or synthetic antioxidative compounds as novel therapeutics. Despite the presence of variegated in vitro and in vivo studies focusing on safety and efficacy issues of these promising therapeutics, nowadays their translation to clinics is far from applicability due to several challenges. In this review, we briefly introduce the enzymatic and non-enzymatic antioxidant defense systems as well as potential signaling pathways related to the pathogenesis of GBM with a special interest in antioxidant mechanisms. In addition, we describe the advantages and limitations of antioxidant supplementation in GBM cases or disease models as well as growing challenges for GBM therapies with antioxidants in the future.

Differences between antioxidant defense parameters and specific trace element concentrations in healthy, benign, and malignant brain tissues

There are only a few reports examining the impact of oxidative stress in patients with benign and malignant brain tumors. In this study we investigated whether there are changes in antioxidant system (AOS) parameters and key trace elements between control, benign and malignant brain tissues. The study also aimed to examine correlations between the analyzed parameters. The study enrolled both types of brain tumors, benign tumors (BT) and malignant tumors (MT). The results were compared with control tissue (CT) without tumor infiltration collected from patients with BT. The following antioxidant parameters were determined: activities of total, manganese-containing, and copper/zinc-containing superoxide dismutase (TotSOD, MnSOD and CuZnSOD), activities of catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase and acetylcholine esterase (AChE), the concentrations of glutathione and sulfhydryl groups and of manganese (Mn), copper (Cu), zinc (Zn), and selenium (Se). BT and MT had altered activities/levels of multiple AOS parameters as compared to CT, indicating that tumor cells had an altered cell metabolism and changes in AOS represent adaptive response to increased oxidative stress. Low MnSOD and AChE and high GST activities were significant for distinguishing between MT and CT. Malignant tissue was also characterized by lower Mn and Cu concentrations relative to CT and BT. Principal Component Analysis clearly discriminated BT from CT and MT (PC1, 66.97%), while PC2 clearly discriminated CT from BT and MT (33.03%). Most correlative relationships were associated with Se in the BT group and Cu in the MT group. The results of this study reveal differences between the AOS parameters and the essential trace elements between the analyzed groups. The observed dysregulations show that oxidative stress could have an important role in disrupting brain homeostasis and its presence in the pathogenesis of benign and malignant brain tumors.

Promising potential of boron compounds against Glioblastoma: In Vitro antioxidant, anti-inflammatory and anticancer studies

Glioblastoma (GB) is the most common and aggressive primary malignant astrocytoma correlated with poor patient survival. There are no curative treatments for GB, and it becomes resistant to chemotherapy, radiation therapy, and immunotherapy. Resistance in GB cells is closely related to their states of redox imbalance, and the role of reactive oxygen species and its impact on cancer cell survival is still far from elucidation. Boron-containing compounds, especially boric acid (BA) and borax (BX) exhibited interesting biological effects involving antibacterial, antiviral, anti-cancerogenic, anti-mutagenic, anti-inflammatory as well as anti-oxidative features. Recent studies indicated that certain boron compounds could be cytotoxic on human GB. Nevertheless, there is gap of knowledge in the literature on exploring the underlying mechanisms of anti-GB action by boron compounds. Here, we identified and compared the potential anti-GB effect of both BA and BX, and revealed their underlying anti-GB mechanism. We performed cell viability, oxidative alterations, oxidative DNA damage potential assays, and explored the inflammatory responses and gene expression changes by real-time PCR using U-87MG cells. We found that BA and BX led to a remarkable reduction in U-87MG cell viability in a concentration-dependent manner. We also found that boron compounds increased the total oxidative status and MDA levels along with the SOD and CAT enzyme activities and decreased total antioxidant capacity and GSH levels in U-87MG cells without inducing DNA damage. The cytokine levels of cancer cells were also altered. We verified the selectivity of the compounds using a normal cell line, HaCaT and found an exact opposite condition after treating HaCaT cells with BA and BX. BA applications were more effective than BX on U-87MG cell line in terms of increasing MDA levels, SOD and CAT enzyme activities, and decreasing Interleukin-1α, Interleukin-6 and Tumor necrosis factor- α (TNF- α) levels. We finally observed that anticancer effect of BA and BX were associated with the BRAF/MAPK, PTEN and PI3K/AKT signaling pathways in respect of downregulatory manner. Especially, BA application was found more favorable because of its inhibitory effect on PIK3CA, PIK3R1, PTEN and RAF1 genes. In conclusion, our analysis indicated that boron compounds may be safe and promising for effective treatment of GB.

Lipid peroxidation in brain tumors

There is a lot of evidence showing that lipid peroxidation plays very important role in development of various diseases, including neurodegenerative diseases and brain tumors. Lipid peroxidation is achieved by two main pathways, by enzymatic or by non-enzymatic oxidation, respectively. In this paper, we focus on non-enzymatic, self-catalyzed chain reaction of poly-unsaturated fatty acid (PUFA) peroxidation generating reactive aldehydes, notably 4-hydroxynonenal (4-HNE), which acts as second messenger of free radicals and as growth regulating factor. It might originate from astrocytes as well as from blood vessels, even within the blood-brain barrier (BBB), which is in case of brain tumors transformed into the blood-brain-tumor barrier (BBTB). The functionality of the BBB is strongly affected by 4-HNE because it forms relatively stable protein adducts thus allowing the persistence and the spread of lipid peroxidation, as revealed by immunohistochemical findings. Because 4-HNE can act as a regulator of vital functions of normal and of malignant cells acting in the cell type- and concentration-dependent manners, the bioactivities of this product of lipid peroxidation be should further studied to reveal if it acts as a co-factor of carcinogenesis or as natural factor of defense against primary brain tumors and metastatic cancer.

Gender differences in the antioxidant response of oral administration of hydroxytyrosol and oleuropein against N-ethyl-N-nitrosourea (ENU)-induced glioma

Brain tumorigenesis has been associated not only with oxidative stress, but also with a reduced response of non-enzyme and enzyme antioxidant defense systems. In fact, the imbalance between free-radical production and the efficiency of the antioxidant defense systems triggers the process because the central nervous system (CNS) is very sensitive to free-radical damage. Phenolic compounds, mainly oleuropein and its major metabolite hydroxytyrosol, derived from olives and virgin olive oil, have been shown to exert important anticancer activities both in vitro and in vivo due to their antioxidant properties. The present study analyzes the effects of the oral administration of oleuropein, hydroxytyrosol and the mixture of both phenolic compounds in rats with transplacental N-ethyl-N-nitrosourea (ENU)-induced brain tumors to analyze their potential effect against brain tumorigenesis through the modification of redox system components. Oxidative stress parameters, non-enzyme and enzyme antioxidant defense systems and blood chemistry were assayed in the different experimental groups. The treatment with oleuropein, hydroxytyrosol and/or the mixture of both phenolic compounds promotes a limited beneficial effect as anticancer compounds in our ENU-induced animal model of brain tumor. These effects occur via redox control mechanisms involving endogenous enzymatic and non-enzymatic antioxidant defense systems, and are highly dependent on the gender of the animals.