Association between CYP2B6 genetic variability and cyclophosphamide therapy in pediatric patients with neuroblastoma.

Cyclophosphamide, an oxazaphosphorine prodrug is frequently used in treatment of neuroblastoma, which is one of the most prevalent solid organ malignancies in infants and young children. Cytochrome P450 2B6 (CYP2B6) is the major catalyst and CYP2C19 is the minor enzyme in bioactivation and inactivation pathways of cyclophosphamide. CYP-mediated metabolism may contribute to the variable pharmacokinetics of cyclophosphamide and its toxic byproducts leading to insufficient response to the therapy and development of clinically significant side effects. The aim of the study was to reveal the contribution of pharmacogenetic variability in CYP2B6 and CYP2C19 to the treatment efficacy and cyclophosphamide-induced side effects in pediatric neuroblastoma patients under cyclophosphamide therapy (N = 50). Cyclophosphamide-induced hematologic toxicities were pivotal in all patients, whereas only moderate hepatorenal toxicity was developed. The patients' CYP2B6 metabolizer phenotypes were associated with the occurrence of lymphopenia, thrombocytopenia, and monocytopenia as well as of liver injury, but not with kidney or urinary bladder (hemorrhagic cystitis) toxicities. Furthermore, the patients' age (< 1.5 years, P = 0.03) and female gender (P ≤ 0.02), but not CYP2B6 or CYP2C19 metabolizer phenotypes appeared as significant prognostic factors in treatment outcomes. Our results may contribute to a better understanding of the impact of CYP2B6 variability on cyclophosphamide-induced side effects.

Recent Evidence-Based Clinical Guide for the Use of Dinutuximab Beta in Pediatric Patients with Neuroblastoma.

The anti-GD2 antibody dinutuximab beta (Qarziba®) has been added to the present standard of care for patients with high-risk neuroblastoma in Europe based on the positive results obtained in different studies. In both the first-line and relapsed/refractory settings, treatment with dinutuximab beta attains objective clinical responses in children with high-risk neuroblastoma. Its incorporation has changed the outcome for these patients and optimized management should be guaranteed to minimize possible adverse effects. Most prevalent adverse events include pain, allergic reactions, fever and capillary leak syndrome. There are still no evidence-based clinical guidelines that include the latest published evidence to optimize its use, as it depends on the experience gained in each referral center. Topics such as the mode of preparation and administration, the concomitant use of interleukin-2, the recommended pediatric age and dose for its use, or the adequate management of possible toxicities are important aspects to review. The objective of this article was to update the clinical guide to management with dinutuximab beta of children with neuroblastoma based on the most recent published evidence and our own experience in clinical practice.

Exposure to nitrosatable drugs during pregnancy and childhood cancer: A matched case-control study in Denmark, 1996-2016.

BACKGROUND: Nitrosatable drugs can be synthesized to N-nitroso compounds in human stomach. In a pregnant woman, N-nitroso compounds can be translocated to the fetus through the placenta. Maternal exposure of nitrosatable compounds during pregnancy has been associated with childhood brain tumors and leukemia. However, few studies have investigated an association between nitrosatable drug exposure during pregnancy and childhood cancer. We examined if maternal prescriptions of nitrosatable drugs received during pregnancy are associated with childhood cancer. METHODS: A matched case-control study was conducted using Danish nationwide registry data from 1995 to 2016. Each childhood cancer case was matched with twenty-five controls. Maternal exposure of nitrosatable drugs during pregnancy was identified from the Danish National Prescription Register. A multivariable conditional logistic regression model was used to estimate adjusted odds ratios (adj.OR) with 95% confidence intervals (CI) for each childhood cancer type. RESULTS: Maternal prescriptions of nitrosatable drugs positively associate with central nervous system tumors (adj.OR = 1.25; 95% CI = 1.04-1.51) and neuroblastoma (adj.OR = 1.96; 95% CI = 1.34-2.85) in offspring. We also observed a positive association between perinatal exposure of nitrosatable drugs and acute lymphoblastic leukemia (adj.OR = 1.31; 95% CI = 1.07-1.59), however, it appeared to be due to confounding by indication, i.e., maternal infections. CONCLUSION: Nitrosatable drug use during pregnancy potentially increased risk of central nervous system tumors and neuroblastoma. While a positive association between maternal prescriptions of nitrosatable drugs and acute lymphoblastic leukemia should be interpreted cautiously because of confounding by indication.

Applications of the Grading Scales for the Detection of Ototoxicity in Children after Treatment of Neuroblastoma and Extracranial Germinal Tumor.

INTRODUCTION: Advances in treatment have resulted in a significant increase in survival rates for patients cured of malignant diseases such as neuroblastoma (NBL) and extracranial germ cell tumor (GCT). NBL is one of the pediatric cancers during which potentially ototoxic cytostatic drugs (cisplatin and carboplatin) are used for treatment. Other cancers include germinal tumors, hepatoblastoma, sarcomas, and brain tumors. Often, this very aggressive treatment has a high risk of causing long-term side effects, including hearing loss. Hence, the present study aimed to evaluate the usefulness of the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Brock, Chang, and International Society of Pediatric Oncology (SIOP) Boston scales in terms of detecting the high-frequency nature of hearing loss induced by ototoxic drugs and monitoring hearing status in children after completion of oncological treatment. Additionally, the frequency of hearing loss in children treated for NBL and extracranial GCT was assessed, and the principles of monitoring hearing in these patients were indicated. METHODS: The study group consisted of 78 patients diagnosed with NBL (n = 47) and GCT (n = 31). There were 23 boys and 24 girls in the NBL group, aged 0-16 years, and 21 boys and 10 girls in the GCT group, aged 0-18 years. The control group consisted of 54 patients who had never received oncological treatment, were not taking potentially ototoxic drugs, and appeared socially efficient in the subjective audiological assessment. Audiometric examinations and DP-acoustic otoemission measurements were performed. Additionally, impedance audiometry tests were done to exclude a possible conductive component of the hearing loss. RESULTS: The analysis shows that ototoxicity-induced hearing loss was observed in 13.8-65.5% of children. 75.9% of patients showed hearing loss in the 16 kHz frequency range, and at least 56.8% of patients showed hearing loss in the frequency range above 12.5 kHz. Hearing impairment, relevant to speech understanding, was displayed by more than 40% of children treated for NBL and GCT. CONCLUSIONS: The confirmation of hearing loss in nearly 65% of cases in both patients indicates the necessity to monitor the long-term side effects of anticancer treatment. Acoustic otoemission measurements, the adoption of articulatory indices based on an audiogram, or the use of arbitrary ototoxicity assessment scales such as Brock, Chang, or SIOP Boston are fully justified techniques for studying ototoxicity induced by cytostatic drugs. However, they all require continuous improvement to increase their sensitivity and specificity, especially in the pediatric group.

A report on second neo-plasms in seven children with solid tumors.

OBJECTIVE: This study aims to investigate the characteristics and related high risk factors of second neoplasms after chemotherapy and radiotherapy in children with solid tumors. METHODS: The detailed clinical data of seven children with malignant solid tumors, who were treated in our department, were retrospectively analyzed, in order to summarize the clinical characteristics of the secondary onset of second neoplasms, and determined the risk factors related to the occurrence of second neoplasms. RESULTS: (1) Clinical characteristics: Among the seven children with malignant solid tumors, three children had rhabdomyosarcoma (3/132, 2.27%), two children had hepatoblastoma (2/313, 0.64%), one child had neuroblastoma (1/305, 0.33%), and one child had inflammatory myofibroblastoma (1/3, 33.33%). Furthermore, among these children, four children were boys and three children were girls, and their onset age ranged within 5-34 months, with a median onset age of 27 months. Moreover, among these children, three children were ≤1 year old. All second neoplasms exhibited symptoms, and the diagnosis was made after the complete remission of the first primary tumor. The time interval between these two tumors was within 17-78 months, and the median time was 38 months. Three of seven children with rhabdomyosarcoma were treated with chemotherapy in combination with radiotherapy, while four children only received the chemotherapy. The chemotherapy cycles were 6-39 times, and the median chemotherapy cycles were 10 times. Among these children, one child with relapsed stage IV rhabdomyosarcoma and one child with stage IV retroperitoneal neuroblastoma had 39 cycles and 33 cycles of chemotherapy respectively. (2) Characteristics of the accumulated doses of high-risk chemotherapy drugs: The accumulated dose of cyclophosphamide in six patients was within 2.47-44.45 g/m2, with a median of 6.14 g/m2. The accumulated dose of ifosfamide in five patients was within 13.63-96.41 mg/m2, with a median of 31.23g/m2. The accumulated dose of etoposide in six patients was within 1,237.35-3,754.95 mg/m2, with a median of 1,548.67 mg/m2. The accumulated dose of anthracyclines in seven patients was within 150.68-843.78 mg/m2, with a median of 329.73 mg/m2. The accumulated dose of vincristine in seven patients was within 3.11-18.89 mg/m2, with a median of 15.92 mg/m2. The accumulated dose of cisplatin in seven patients was within 271.23-1,681.59 mg/m2, with a median of 733.07 mg/m2. Children with abdominal inflammatory myofibroblastic tumors did not apply cyclophosphamide, ifosfamide and etoposide regimens. The main chemotherapy drugs consisted of methotrexate, pirarubicin, cisplatin and vincristine. (3) Radiotherapy doses. (4) Characteristics of second neoplasms: Among the seven children with second neoplasms, five children had leukemia, 3 patients with rhabdomyosarcoma were combined with radiotherapy. The doses of radiation were 40 and 45GY" after "(3) Radiotherapy doses (four children had acute myeloid leukemia and one children had acute B-lymphoblastic leukemia), one child had myelodysplastic syndrome, and one child had myeloid sarcoma. Furthermore, among these seven children, four children (4/7) had abnormal chromosomes, two children were normal, and one child gave up the treatment and underwent the chromosome test after the diagnosis of second neoplasms. CONCLUSION: The incidence of secondary onset of second neoplasms in children with malignant solid tumors is not high, considering that this is correlated to the use of alkylating agents, topoisomerase II inhibitors, platinum-based chemotherapy drugs and radiotherapy, and associated with the chromosomal abnormalities of children. KEY WORDS: Chemotherapy, Children, Radiotherapy, Second malignant neoplasm, Solid tumor.

How we approach the treatment of patients with high-risk neuroblastoma with naxitamab: experience from the Hospital Sant Joan de Déu in Barcelona, Spain.

Naxitamab [humanized 3f8 (hu3F8)] is a humanized monoclonal antibody (mAb) targeting the disialoganglioside GD2. It was approved in 2020 by the United States Food and Drug Administration (FDA) in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) for treatment of pediatric and adult patients with relapsed/refractory high-risk neuroblastoma, limited to the bone or bone marrow (BM). The team at Sant Joan de Déu Children's Hospital in Barcelona, Spain, have been using naxitamab to treat neuroblastoma under clinical trial protocols [e.g. Trial 201, and hu3F8, irinotecan, temozolomide, and sargramostim (GM-CSF) (HITS) study] and compassionate use since 2017. The team has experience with two primary regimens: naxitamab with GM-CSF only, or naxitamab in combination with irinotecan, temozolomide, and GM-CSF (chemoimmunotherapy). This article aims to provide a practical overview of the team's experience with naxitamab to date, including preparing the treatment room and selecting the team. Adverse event management, including the use of ketamine to manage pain during anti-GD2 mAb infusions, is also discussed. We hope this will provide practical information for other health care providers considering offering this treatment.

Pre-conceptional and prenatal exposure to pesticides and pediatric neuroblastoma. A meta-analysis of nine studies.

Neuroblastoma is primarily an embryonal tumor of infancy. Recently, some toxicological agents used as pesticides have been associated with an increased incidence of this tumor. We intended to determine the potential association between prenatal exposure to pesticides and the incidence of neuroblastoma in children. Studies targeting the link between neuroblastoma and pesticides were searched in PUBMED, SCOPUS, and Google Scholar from January 1, 1960, through December 2020. We performed a PRISMA-based systematic review and meta-analysis. In addition, we took into consideration the IARC evaluation on pesticides issued in recent monographs. Prenatal pesticide exposure is associated with an increased risk of neuroblastoma with an OR of 1.6 (1.1-2.3; p = 0.013), while the OR is 1.0 (0.8-1.3; p = 0.723) for pesticide exposure after birth. There is a significant association between prenatal pesticide exposure and neuroblastoma. We emphasize the IARC conclusions evaluating the carcinogenicity of diazinon, glyphosate, malathion, parathion, and tetrachlorvinphos.

Quantitative analysis of neuronal mitochondrial movement reveals patterns resulting from neurotoxicity of rotenone and 6-hydroxydopamine.

Alterations in mitochondrial dynamics, including their intracellular trafficking, are common early manifestations of neuronal degeneration. However, current methodologies used to study mitochondrial trafficking events rely on parameters that are primarily altered in later stages of neurodegeneration. Our objective was to establish a reliable applied statistical analysis to detect early alterations in neuronal mitochondrial trafficking. We propose a novel quantitative analysis of mitochondria trajectories based on innovative movement descriptors, including straightness, efficiency, anisotropy, and kurtosis. We evaluated time- and dose-dependent alterations in trajectory descriptors using biological data from differentiated SH-SY5Y cells treated with the mitochondrial toxicants 6-hydroxydopamine and rotenone. MitoTracker Red CMXRos-labelled mitochondria movement was analyzed by total internal reflection fluorescence microscopy followed by computational modelling to describe the process. Based on the aforementioned trajectory descriptors, this innovative analysis of mitochondria trajectories provides insights into mitochondrial movement characteristics and can be a consistent and sensitive method to detect alterations in mitochondrial trafficking occurring in the earliest time points of neurodegeneration.

Long non-coding RNA NORAD functions as a microRNA-204-5p sponge to repress the progression of Parkinson's disease in vitro by increasing the solute carrier family 5 member 3 expression.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Long non-coding RNAs have important regulatory values in various human diseases. Non-coding RNA Activated by DNA Damage (NORAD) was reported to regulate PD progression in vitro, but its functional mechanism is fully unknown. We used 1-methyl-4-phenylpyridinium (MPP+ ) to establish the cell-based PD model. NORAD, microRNA-204-5p (miR-204-5p), and solute carrier family 5 member 3 (SLC5A3) levels were quantified using the quantitative real-time polymerase chain reaction. Cell viability and apoptosis were determined by Cell Counting Kit-8 and flow cytometry, respectively. The protein levels were analyzed via western blot. Cytotoxicity was assessed by the released lactate dehydrogenase level in cell supernatant. Oxidative stress and inflammation were measured by the standard indicators. Dual-luciferase reporter and RNA immunoprecipitation assays were performed for intergenic combination. First, we found that NORAD was obviously reduced in MPP+ -treated neuroblastoma cells and lightened the MPP+ -induced cytotoxicity, oxidative stress, and inflammatory response. Then, NORAD was shown to be a miR-204-5p sponge and avoided the injury induced by MPP+ in neuroblastoma cells via targeting miR-204-5p. SLC5A3 was a miR-204-5p target and could be regulated by NORAD/miR-204-5p axis. SLC5A3 knockdown assuaged the anti-miR-204-5p-induced protection for neuroblastoma cells from MPP+ . Altogether, NORAD played a neuroprotective role against the progression of MPP+ -induced PD model in neuroblastoma cells relying on the miR-204-5p/SLC5A3 axis. This study afforded the clear elaboration on the PD pathomechanism concerning NORAD.

Hydrogen sulfide alleviates oxidative stress injury and reduces apoptosis induced by MPP+ in Parkinson's disease cell model.

Hydrogen sulfide (H2S), an endogenously produced gas, is a cardioprotective agent against neurotoxin-induced neurodegeneration in Parkinson's disease (PD). However, the roles of H2S in 1-methyl-4-phenylpyridinium ion (MPP+)-treated SH-SY5Y cells with the involvement of reactive oxygen species-nitric oxide (ROS-NO) signaling pathway in PD remain unclear. For this study, a MPP+-treated SH-SY5Y cell model was established to explore the regulatory role of H2S in oxidative stress injury and cell apoptosis. With the cell viability, apoptosis, cytotoxicity, levels of reactive oxygen species (ROS) and nitric oxide (NO), mitochondrial transmembrane potential (Δψm), contents of oxidative stress injury-related markers (glutathione, superoxide dismutase, malondialdehyde), levels of apoptosis-related proteins (Caspase 3, Bax, Bcl-2) and inducible nitric oxide synthase (iNOS) determined, this study demonstrated that NaHS (an H2S donor) treatment could alleviated the reduction of cell viability and cytotoxicity, cell apoptosis, Δψm loss, contents of ROS and NO, and oxidative stress injury induced by MPP+. The present study showed that H2S may protect SH-SY5Y cells from MPP+-induced injury in PD cell model via the inhibition of ROS-NO signaling pathway and provide insight into the potential of H2S for PD therapy.

Characterization of lactic acid bacteria derived exopolysaccharides for use as a defined neuroprotective agent against amyloid beta1-42-induced apoptosis in SH-SY5Y cells.

Alzheimer's disease (AD) is a disease characterized by cerebral neuronal degeneration and loss in a progressive manner. Amyloid beta (Aß) in the brain is toxic to neurons, being a main risk factor for initiation and continuation of cognitive deterioration in AD. Neurotoxicity of Aß origin is also linked to oxidative stress characterized by excessive lipid peroxidation, protein oxidation, changes in antioxidant systems, and cerebral DNA damage in AD. Furthermore, Aß can induce oxidative neuronal cell death by a mitochondrial dysfunction. Cellular injury caused by oxidative stress can be possibly prevented by boosting or promoting bodily oxidative defense system by supplying antioxidants in diet or as medications. However, most synthetic antioxidants are found to have cytotoxicity, which prevents their safe use, and limits their administration. For this reason, more attention has been paid to the natural non-toxic antioxidants. One of the most promising groups of non-toxic antioxidative compounds is thought to be polysaccharides. This study investigated the characterization and protective action exerted by exopolysaccharides (EPSs) originated from Lactobacillus delbrueckii ssp. bulgaricus B3 and Lactobacillus plantarum GD2 to protect from apoptotic activity exerted by Aß1-42 among SH-SY5Y cells. We characterized EPSs by elemental analysis, FTIR, AFM, SEM, and XRD. The antioxidant effects of EPSs were determined by the DPPH free radical scavenging activity, hydroxyl radical scavenging activity, metal ion chelating activity, lipid peroxidation inhibitory activity, and superoxide anion scavenging activity method. The protective effects of EPSs were determined by flow cytometry and RT-PCR. Mannose ratio, molecular weight, functional groups, surface morphology, and amorphous character structure of EPSs are thought to play a role in the protective effect of EPSs. EPSs reduced apoptotic activity of Aß1-42 in addition to their depolarizing effect on mitochondrial membrane potential in concentration-dependent manner. These observations contribute the inclusion of EPSs among the therapeutic options used to manage various neurological disorders in the traditional medicine in a scientific manner, indicating that EPSs may be promising natural chemical constituents that need advanced research and development for pharmacological therapy of AD.

Protective and Modulatory Effects of Trapa bispinosa and Trigonella foenum-graecum on Neuroblastoma Cells Through Neuronal Nitric Oxide Synthase.

The fruits of Trapa bispinosa (TB) and seeds of Trigonella foenum-graecum (TF) are used for their nutraceutical properties in various systems of traditional medicine practiced in India. In this study aqueous and methanolic extracts of TB fruits and TF seeds were prepared and their protective effect was studied on hydrogen peroxide (H2O2)-treated neuroblastoma (NB-41) cell line. Cell viability, nitric oxide (NO) levels, mRNA, and protein profiles were analyzed and compared with untreated control. Results show that aqueous extracts of both TB and TF provide significant protection to neuroblastoma cells with TF aqueous extract offering better protection through upregulation of neuronal nitric oxide synthase (nNOS) against hydrogen peroxide generated stress. This is the first report demonstrating protection of neuronal cell lines by use of TB and TF extracts through modulation of nNOS activity.

3-Acetyl-11-keto-ß-boswellic acid attenuated oxidative glutamate toxicity in neuron-like cell lines by apoptosis inhibition.

3-Acetyl-11-keto-ß-boswellic acid (AKBA), a pentacyclic triterpenic acid present in gum resin of Boswellia serrata, has been found to possess antioxidant and neuroprotective properties. In this study, we aimed to examine protective properties of AKBA against glutamate-induced neuronal injury. To investigate the effects of AKBA (2.5-10 µM) on glutamate injury in neuron-like cells PC12 and N2a, two treatment regimens (incubation for 2 or 0 hours before glutamate exposure) were used. Then, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method was used to determine viability of the cells. Cellular redox status was evaluated using fluorimetry and comet assays. Annexin V/propidium iodide double staining and Western blot analysis of relative apoptotic proteins were conducted. Based on the results, 24 hours incubation with glutamate (8 mM) increased the cell mortality of PC12 and N2a (P < .001). However, AKBA (2.5-10 µM) enhanced the cell viability in both treatment regimens (P < .001). Also co- and pretreatment with AKBA significantly attenuated lipid peroxidation, reactive oxygen species production, and DNA injury (P < .05 and P < .001). AKBA also restored the activity of cellular superoxide dismutase under glutamate toxicity; this effect was seen to be more significant during the pretreatment regimen (P < .001). Moreover, Western blot analysis indicated that AKBA inhibited glutamate-induced programmed cell death through depressing the elevation of the expression ratio of Bax/Bcl-2 and cleaved-caspase-3 proteins, concentration-dependently. Overall, the present findings suggest the neuroprotective activities of AKBA against glutamate-induced cell injury probably by inhibiting oxidative damage and reducing apoptotic cell death.

Apelin-36 exerts the cytoprotective effect against MPP+-induced cytotoxicity in SH-SY5Y cells through PI3K/Akt/mTOR autophagy pathway.

AIMS: Parkinson's disease (PD) is a common neurodegenerative disease typically associated with the accumulation of α-synuclein. Autophagy impairment is thought to be involved in the dopaminergic neurodegeneration in PD. We investigate the effect of Apelin-36 on the activated phosphatidylinositol 3-kinase (PI3K)/protein kinase B(Akt)/the mammalian target of rapamycin (mTOR) autophagy pathway in 1-methyl-4-phenylpyridinium (MPP+)-treated SH-SY5Y cells, which is involved in the cytoprotective effect of Apelin-36. MAIN METHODS: SH-SY5Y cells were treated with 1-Methyl-4-phenylpyridine (MPP+) with or without Apelin-36. The cell viability, apoptotic ratio, the form of autophagic vacuoles, the expression of tyrosine hydroxylase (TH), α-synuclein, phosphorylation of PI3K, AKT, mTOR, microtubule-associated protein 1 Light Chain 3 II/I (LC3II/I) and p62 were detected to investigate the neuroprotective effect of Apelin-36. KEY FINDINGS: The results indicate that Apelin-36 significantly improved the cell viability and decreased the apoptosis in MPP+-treated SH-SY5Y cells. The decreased expression of tyrosine hydroxylase (TH) induced by MPP+ was significantly increased by Apelin36 pretreatment. Moreover, Apelin36 significantly increased the autophagic vacuoles. The ratio of LC3II/I was significantly increased by Apelin36, as well as the decreased p62 expression. In addition, the activated PI3K/AKT/mTOR pathway induced by MPP+ was significantly inhibited by Apelin36. Additionally, Apelin36 significantly decreased the α-synuclein expression. Furthermore, the cytoprotective effect of Apelin-36 was weakened by pretreatment with Insulin-like Growth Factor-1 (IGF-1), an activator of PI3K/Akt, and MHY1485, an mTOR activator. SIGNIFICANCE: Our results demonstrated that Apelin-36 protects against MPP+-induced cytotoxicity through PI3K/Akt/mTOR autophagy pathway in PD model in vitro, which provides a new theoretical basis for the treatment of PD.

Small molecule diketone flavorants diacetyl and 2,3-pentanedione promote neurotoxicity but inhibit amyloid ß aggregation.

We investigated the effects of the small molecule flavorants diacetyl, 2,3-pentanedione and acetoin on neuronal cell viability and ß amyloid aggregation and morphology. Two neuroblastoma cell lines, SH-SY5Y and Neuro 2a (N2a) were exposed to diacetyl, 2,3-pentanedione and acetoin, while Thioflavin T fluorescence kinetics and transmission electron microscopy were used to assess effects on Aß1-42 fibril and aggregate formation and morphology respectively. Diacetyl was intrinsically toxic to both SH-SY5Y and N2a cells, with time and concentration-dependent reductions in cell viability occurring over 24 h and 48 h incubation periods. 2.3-Pentanedione evoked a similar concentration-dependent loss of cell viability in N2a cells at 48 h, but exhibited lessened toxicity in SH-SY5Y cells over 24 h, and minimal loss of cell viability by 48 h. Diacetyl inhibited Aß1-42 aggregation kinetics, reduced aggregate and fibril density and rendered Aß1-42 into amorphous small aggregates. 2,3-Pentanedione also reduced overall aggregate formation, but to a lesser extent than diacetyl and retaining the presence of a meshwork of Aß1-42 aggregates and fibrils. Acetoin was innocuous to neuronal cells and did not alter Aß1-42 fibril density or morphology. These findings highlight the intrinsic neurotoxicity of small molecule diketone flavorants. While providing further insight into their molecular interactions with amyloidogenic proteins, the neurotoxicity of such flavorants is a significant finding and warrants further investigation.

Grewia tiliaefolia and its active compound vitexin regulate the expression of glutamate transporters and protect Neuro-2a cells from glutamate toxicity.

AIM: Glutamate is a major neurotransmitter involved in several brain functions and glutamate excitotoxicity is involved in Alzheimer's disease (AD). In the current study, the neuroprotective effect of the Indian medicinal plant Grewia tiliaefolia (GT) and its active component vitexin was evaluated in Neuro-2a cells against glutamate toxicity. MATERIALS AND METHODS: Neuro-2a cells were exposed to glutamate to cause excitotoxicity and the neuroprotective effect of GT and vitexin were evaluated using biochemical studies (estimation of reactive oxygen species, reactive nitrogen species, protein carbonyl content, lipid peroxidation level, mitochondrial membrane potential and caspase-3 activity), molecular docking studies, gene expression and western blot analysis. KEY FINDINGS: Glutamate exposure to Neuro-2a cells induced oxidative stress, loss of membrane potential, suppressed the expression of antioxidant response genes (Nrf-2, HO-1, NQO-1), glutamate transporters (GLAST-1, GLT-1) and induced the expression of NMDAR, Calpain. However, pre-treatment of cells with GT/vitexin inhibited oxidative stress mediated damage by augmenting the expression of Nrf-2/HO-1 pathway, inducing the expression of glutamate transporters and downregulating Calpain, NMDAR. Molecular docking showed that vitexin effectively binds to NMDAR and GSK-3ß and thereby can inhibit their activation. GT/vitexin also inhibited glutamate induced Bax expression. SIGNIFICANCE: Methanol extract of G. tiliaefolia and its active component vitexin can act in an antioxidant dependent mechanism as well as by regulating glutamate transporters in mitigating the toxicity exerted by glutamate in Neuro-2a cells. Our results conclude that GT/vitexin can act as potential drug leads for the therapeutic intervention of AD.

Diphenyl diselenide protects against methylmercury-induced inhibition of thioredoxin reductase and glutathione peroxidase in human neuroblastoma cells: a comparison with ebselen.

Exposure to methylmercury (MeHg), an important environmental toxicant, may lead to serious health risks, damaging various organs and predominantly affecting the brain function. The toxicity of MeHg can be related to the inhibition of important selenoenzymes, such as glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). Experimental studies have shown that selenocompounds play an important role as cellular detoxifiers and protective agents against the harmful effects of mercury. The present study investigated the mechanisms by which diphenyl diselenide [(PhSe)2 ] and ebselen interfered with the interaction of mercury (MeHg) and selenoenzymes (TrxR and GPx) in an in vitro experimental model of cultured human neuroblastoma cells (SH-SY5Y). Our results established that (PhSe)2 and ebselen increased the activity and expression of TrxR. In contrast, MeHg inhibited TrxR activity even at low doses (0.5 µm). Coexposure to selenocompounds and MeHg showed a protective effect of (PhSe)2 on both the activity and expression of TrxR. When selenoenzyme GPx was evaluated, selenocompounds did not alter its activity or expression significantly, whereas MeHg inhibited the activity of GPx (from 1 µm). Among the selenocompounds only (PhSe)2 significantly protected against the effects of MeHg on GPx activity. Taken together, these results indicate a potential use for ebselen and (PhSe)2 against MeHg toxicity. Furthermore, for the first time, we have demonstrated that (PhSe)2 caused a more pronounced upregulation of TrxR than ebselen in neuroblastoma cells, likely reflecting an important molecular mechanism involved in the antioxidant properties of this compound. Copyright © 2017 John Wiley & Sons, Ltd.

Limonoids with neuroprotective activity from the stems of Clausena emarginata.

Two new limonoids, clauemargines M-N (1-2), together with five known compounds (3-7), were isolated from the stems of Clausena emarginata, and compounds 6 and 7 were gained from this plant for the first time. Their structures were established and elucidated on the basis of comprehensive spectroscopic analysis. The absolute configurations of 1-2 were further determined by the octant rule of saturated cyclic ketone. Compounds 1, 2, 4, and 5 showed moderate neuroprotective effects against L-glutamic acid-induced cellular damage in human neuroblastoma SK-N-SH cells at 10 µM.

The combination of 1α,25dihydroxyvitaminD3 with resveratrol improves neuronal degeneration by regulating endoplasmic reticulum stress, insulin signaling and inhibiting tau hyperphosphorylation in SH-SY5Y cells.

Endoplasmic reticulum (ER) stress is a critical factor involved in the pathogenesis of Alzheimer's disease (AD). Vitamin D and resveratrol are two nutritional factors that have reported neuroprotective effects, and findings from cellular models suggest that resveratrol could potentiate vitamin D's effects. We aimed to determine the effects of vitamin D & resveratrol on ER stress mediated neurodegeneration and whether synergistic effects existed. Tunicamycin and Aß25-35 was utilized to induce ER stress in SH-SY5Y cells, cells were then incubated with vitamin D and resveratrol. The combination of vitamin D & resveratrol completely reversed tunicamycin and Aß25-35 induced cytotoxicity in SH-SY5Y cells, as well as elevation in ER stress markers (i.e.GRP78, p-eIF2α and CHOP), insulin signaling disruption (i.e. elevation in p-IRS-1serine307 and reduction in p-Akt serine473) and tau phosphorylation (i.e. reduction in p-GSK3ß serine9, and elevation in p-Tau serine396 &404). Further studies are required to clarify whether the observed synergistic effects in the present study would also existed in vivo, this will lay scientific foundation whether the combination of vitamin D with resveratrol might be an effective maneuver in the treatment of AD in human subjects.

Neuroprotective Xanthones from the Root Bark of Cudrania tricuspidata.

Seventeen new prenylated xanthones (1-17) were isolated from an ethyl acetate-soluble extract of root bark of Cudrania tricuspidata together with 17 previously identified xanthones. The structures of the new compounds were elucidated by spectroscopic methods. Six new compounds (3, 7, 8, 9, 15, and 16) and six known compounds (18-23) showed neuroprotective effects against 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells, with EC50 values of 0.7-16.6 µM.