C6 Rat Glioma Cell Line Research Articles

Effect of Xanthohumol, a Bioactive Natural Compound from Hops, on Adenosine Pathway in Rat C6 Glioma and Human SH-SY5Y Neuroblastoma Cell Lines.

Xanthohumol (Xn) is an antioxidant flavonoid mainly extracted from hops (Humulus lupulus), one of the main ingredients of beer. As with other bioactive compounds, their therapeutic potential against different diseases has been tested, one of which is Alzheimer's disease (AD). Adenosine is a neuromodulatory nucleoside that acts through four different G protein-coupled receptors: A1 and A3, which inhibit the adenylyl cyclases (AC) pathway, and A2A and A2B, which stimulate this activity, causing either a decrease or an increase, respectively, in the release of excitatory neurotransmitters such as glutamate. This adenosinergic pathway, which is altered in AD, could be involved in the excitotoxicity process. Therefore, the aim of this work is to describe the effect of Xn on the adenosinergic pathway using cell lines. For this purpose, two different cellular models, rat glioma C6 and human neuroblastoma SH-SY5Y, were exposed to a non-cytotoxic 10 µM Xn concentration. Adenosine A1 and A2A, receptor levels, and activities related to the adenosine pathway, such as adenylate cyclase, protein kinase A, and 5'-nucleotidase, were analyzed. The adenosine A1 receptor was significantly increased after Xn exposure, while no changes in A2A receptor membrane levels or AC activity were reported. Regarding 5'-nucleotidases, modulation of their activity by Xn was noted since CD73, the extracellular membrane attached to 5'-nucleotidase, was significantly decreased in the C6 cell line. In conclusion, here we describe a novel pathway in which the bioactive flavonoid Xn could have potentially beneficial effects on AD as it increases membrane A1 receptors while modulating enzymes related to the adenosine pathway in cell cultures.

In Vitro and In Silico Anti-Glioblastoma Activity of Hydroalcoholic Extracts of Artemisia annua L. and Artemisia vulgaris L.

Glioblastoma, the most aggressive and challenging brain tumor, is a key focus in neuro-oncology due to its rapid growth and poor prognosis. The C6 glioma cell line is often used as a glioblastoma model due to its close simulation of human glioma characteristics, including rapid expansion and invasiveness. Alongside, herbal medicine, particularly Artemisia spp., is gaining attention for its anticancer potential, offering mechanisms like apoptosis induction, cell cycle arrest, and the inhibition of angiogenesis. In this study, we optimized extraction conditions of polyphenols from Artemisia annua L. and Artemisia vulgaris L. herbs and investigated their anticancer effects in silico and in vitro. Molecular docking of the main phenolic compounds of A. annua and A. vulgaris and potential target proteins, including programmed cell death (apoptosis) pathway proteins proapoptotic Bax (PDB ID 6EB6), anti-apoptotic Bcl-2 (PDB ID G5M), and the necroptosis pathway protein (PDB ID 7MON), mixed lineage kinase domain-like protein (MLKL), in complex with receptor-interacting serine/threonine-protein kinase 3 (RIPK3), revealed the high probability of their interactions, highlighting the possible influence of chlorogenic acid in modulating necroptosis processes. The cell viability of rat C6 glioma cell line was assessed using a nuclear fluorescent double-staining assay with Hoechst 33342 and propidium iodide. The extracts from A. annua and A. vulgaris have demonstrated anticancer activity in the glioblastoma model, with the synergistic effects of their combined compounds surpassing the efficacy of any single compound. Our results suggest the potential of these extracts as a basis for developing more effective glioblastoma treatments, emphasizing the importance of further research into their mechanisms of action and therapeutic applications.

Anoikis and cancer cell differentiation: novel modes of shikonin derivatives anticancer action in vitro.

Shikonin is a naturally occurring naphthoquinone found in the roots of several genera of the Boraginaceae family, widely known for its numerous biological activities, such as antiinflammatory, antioxidant, antimicrobial and anticancer. In this study, the antitumor effect of six naphthoquinones isolated from the roots of Onosma visianii was evaluated using two cell lines, mouse melanoma B16 and highly aggressive rat glioma cell line C6. All examined shikonins dose-dependently decreased the viability of tested cells, with compounds 5 and 6 being the most potent ones and hence subjected to further analysis. The diminished viability of B16 melanoma cells was in correlation with detected caspase-mediated apoptosis. Importantly, observed altered cell morphology along with the loss of dividing potential upon exposure to both shikonins implied reprogram of B16 cell phenotype. Elevated expression of myelin basic protein indicated the acquirement of Schwann-like cell phenotype, while detected autophagy might be connected to this phenomenon. On the contrary, upon exposure to both agents, C6 cells underwent specific cell death-anoikis, provoked by detachment from the extracellular matrix and compromised integrin signaling. Oppositely to compound 5, compound 6 realized anoikis in a caspase-independent manner and under sustained ERK1/2 activation, indicating the deviation from standard proanoikis signaling. Herein, we have pointed out the diversity and novelty in the mode of action of shikonin derivatives depending on the tumor cell features, which represents a good platform for new investigations of these promising natural compounds.

Expression of brain-derived neurotrophic factor and formation of migrasome increases in the glioma cells induced by the adipokinetic hormone.

It has been previously shown that brain-derived neurotrophic factor is linked with various types of cancer. Brain-derived neurotrophic factor is found to be highly expressed in multiple human cancers and associated with tumor growth, invasion, and metastasis. Adipokinetic hormones are functionally related to the vertebrate glucagon, as they have similar functionalities that manage the nutrient-dependent secretion of these two hormones. Migrasomes are new organelles that contain numerous small vesicles, which aid in transmitting signals between the migrating cells. Therefore, the aim of this study was to investigate the effects of Anax imperator adipokinetic hormone on brain-derived neurotrophic factor expression and ultrastructure of cells in the C6 glioma cell line. The rat C6 glioma cells were treated with concentrations of 5 and 10 Anax imperator adipokinetic hormone for 24 h. The effects of the Anax imperator adipokinetic hormone on the migrasome formation and brain-derived neurotrophic factor expression were analyzed using immunocytochemistry and transmission electron microscope. The rat C6 glioma cells of the 5 and 10 μM Anax imperator adipokinetic hormone groups showed significantly high expressions of brain-derived neurotrophic factor and migrasomes numbers, compared with the control group. A positive correlation was found between the brain-derived neurotrophic factor expression level and the formation of migrasome, which indicates that the increased expression of brain-derived neurotrophic factor and the number of migrasomes may be involved to metastasis of the rat C6 glioma cell line induced by the Anax imperator adipokinetic hormone. Therefore, the expression of brain-derived neurotrophic factor and migrasome formation may be promising targets for preventing tumor proliferation, invasion, and metastasis in glioma.

Synthesis of Some New 1,3,4-Oxadiazole Derivatives and Evaluation of Their Anticancer Activity.

In this work, some new 2-[(5-((2-acetamidophenoxy)methyl)-1,3,4-oxadiazol-2-yl)thio]acetamide derivatives (4a-4l) were synthesized and studied for their anticancer activity. Twelve new compounds were tested on the A549 human lung cancer cell line, C6 rat glioma cell line, and L929 murine fibroblast cell line. Compounds 4f, 4i, 4k, and 4l (IC50: 1.59-7.48 μM), and especially 4h (IC50: <0.14 μM), exhibited excellent cytotoxic profile on A549 with selectivity. Compounds 4g and 4h showed remarkable antiproliferative activity on the C6 cell line with IC50 values of 8.16 and 13.04 μM, respectively. The compounds with the lowest IC50 value on the A549 cell line (4f, 4h, 4i, 4k, and 4l) were further studied to determine the mechanism of action. These compounds were found to induce apoptosis with a higher ratio (16.10-21.54%) than that of the standard drug cisplatin (10.07%). Compound 4f displayed mitochondrial membrane depolarization and caspase-3 activation at most, whereas compounds 4h (89.66%) and 4i (78.78%) had outstanding retention rates in the G0/G1phase of the cell cycle (cisplatin 74.75%). Compounds 4f, 4g, 4h, and 4l exhibited matrix metalloproteinase-9 (MMP-9) inhibition higher than 75% at 100 μg/mL; even IC50 values were found to be 1.65 and 2.55 μM for 4h and 4l. In addition, in silico physicochemical properties of the compounds and molecular docking interaction of compound 4h on the MMP-9 enzyme were evaluated; the desired and expected results were obtained.

Toxicity of Carboplatin-Niosomal Nanoparticles in a Brain Cancer Cell Line.

Cancer poses a significant challenge in modern medicine, standing as the primary cause of death in many countries, second only to cardiovascular diseases. Among the various treatments available, carboplatin, a chemotherapy drug, is employed for specific cancer types, including brain carcinoma. The main objective of this investigation is to enhance the therapeutic efficacy of carboplatin by utilizing niosomal nanocarriers. We synthesized nanoniosomal carboplatin using the reverse-phase evaporation technique and conducted an assessment of its particle size, zeta potential, and drug-release properties. Subsequently, we evaluated the cytotoxicity of nanoniosomal carboplatin using the C6 rat glioma cell line. Our research revealed that these niosomal nanoparticles possessed a particle size of 290.5±5.5 nm and a zeta potential of -21.7±7.4 mV. The amount of encapsulated drug and drug loading level were found to be 60.2±2.3% and 2.5±1.1%, respectively. Importantly, the cytotoxic impact of these nanoniosomes on the C6 rat glioma cell line exhibited a significant increase compared to the free drug (P<0.05). Based on our discoveries, it is evident that carboplatin niosomal nanocarriers hold potential as an innovative approach to chemotherapy for brain cancer therapy.

Effects of mitragynine on viability, proliferation, and migration of C6 rat glioma, SH-SY5Y human neuroblastoma, and HT22 immortalized mouse hippocampal neuron cell lines

Mitragynine (MG) is an indole alkaloid found in the extract of Mitragyna speciosa Korth native to Southeast Asia. Although MG is known for its pain-relieving and psychoactive effects, reports have suggested that it has therapeutic potential against neoplasms and psychiatric disorders. However, no evidence currently exists to support the effect of MG on brain tumors. This study aimed to investigate the antitumor effects of MG in C6 rat glioma and SH-SY5Y human neuroblastoma tumor cell lines compared with those in the non-tumor HT22 mouse hippocampal neuronal cell line. MTT assay for cell viability, clonogenic and wound healing assays for cell migration, Hoechst 33342/propidium iodide staining for nuclear morphology, and cell cycle distribution using flow cytometry were performed. MG at 125.47 μM (50 μg/ml) significantly reduced the viability of all cell lines, and the clonogenicity of C6 glioma cells began decreasing at 75.28 μM (30 μg/ml) of MG. Cell migration was inhibited in C6 and HT22 cells treated with 75.28 μM (30 μg/ml) of MG. Apoptotic nuclear condensation and fragmentation were observed in all cell lines treated with 125.47 μM (50 μg/ml) MG, whereas late-phase apoptotic cells were predominant in the group treated with 250.94 μM (100 μg/ml) of MG. The cell cycle assay results suggest that MG arrested the S phase in the C6 cell line and the G2/M phase in the HT22 cell lines. This study showed that MG induces cell death and cell cycle arrest, disrupting cell migration and reducing the clonogenicity of brain tumor cells.

Exogenous Ceramide Treatment Induce Death and Cytotoxicity in Glioma Cells.

To evaluate the cytotoxic and proapoptotic effects of C6 ceramide on the C6 rat glioma cell line. The C6 rat glioma cell line was evaluated. Using a confocal microscope and the appropriate software, the cytotoxic effects of C6 ceramide were identified using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) colorimetric experiments. Transmission electron microscopy (TEM) was utilized to examine the ultrastructural changes following treatment with IC50 concentrations of C6 ceramide. Condensation and fragmentation of nuclei and DNA laddering was observed, indicating apoptotic cell death. C6 ceramide induced apoptosis and effectively caused cytotoxicity in the C6 glioblastoma cells. MTT assay demonstrated > 90% cell death after short-term application of C6 ceramide, confirming its apoptosis-triggering effect. Apoptosis was also confirmed via confocal microscopy and TEM. Glioblastoma cells undergo apoptosis when exposed to C6 ceramide, which makes it a potential chemotherapeutic agent for the treatment of this aggressive brain cancer.

New class of fused [3,2-b][1,2,4]triazolothiazoles for targeting glioma in vitro

Glioma is aggressive malignant tumor with limited therapeutic interventions. Herein we report the synthesis of fused bicyclic 1,2,4-triazolothiazoles by a one-pot multi-component approach and their activity against C6 rat and LN18 human glioma cell lines. The target compounds 2-(6-phenylthiazolo[3,2–b][1,2,4]triazol-2-yl) isoindoline-1,3-diones and (E)-1-phenyl-N-(6-phenylthiazolo[3,2–b][1,2,4]triazol-2-yl) methanimines were obtained by the reaction of 5-amino-4H-1,2,4-triazole-3-thiol with substituted phenacyl bromide, phthalic anhydride, and different aromatic aldehydes in EtOH/HCl under reflux conditions. In C6 rat glioma cell lines, compounds 4g and 6i showed good cytotoxic activity with IC50 values of 8.09 and 8.74 μM, respectively, resulting in G1 and G2-M phase arrest of the cell cycle and activation of apoptosis by modulating phosphorylation of ERK and AKT pathway.

Exposure of aluminium to C6 glioma cells modulates molecular and functional neurotoxic markers.

The risk of aluminium exposure to humans is very high as it may get into the human body through excessive dietary contaminants, inhalation of fine particulate matter, or through parenteral routes as a vaccine adjuvant and so forth. The increased level of aluminium in brain tissue has been shown to be associated with several neurodegenerative and neurotoxic adverse effects, including AD. However, the exact mechanism of aluminium-induced neurotoxicity is still unclear. Therefore, our study aimed to investigate the mechanism of neurotoxic and neurodegenerative effects through in vitro exposure of aluminium in rat glioma C6 cell line. The findings of our study have indicated that aluminium chloride exposure may lead to alteration in acetylcholine levels, increased oxidative imbalanceand induction of molecular structural and functional markers of neuronal inflammation. This study also demonstrated that aluminium exposure may lead to the induction of caspase-3 along with apoptotic cell death and a significant increase in amyloid-beta and hyperphosphorylated tau levels in C6 cells. Thus, this study may provide a mechanistic understanding of the regulation of neuroinflammatory and neurodegenerative biomarkers due to aluminium exposure.

Investigation of the Anticancer Effect of S-Allyl-L Cysteine on the C6 Rat Glioma Cell Line in vitro in 2D- and 3D-Cell Culture Models.

In our study, we aimed to investigate the effects of SAC on C6 glioblastoma cells and its antiproliferative and apoptotic effects on two- and three-dimensional cell culture systems. The rat glioma cell line C6 was separated into 2D-Control, 2D-SAC, 3D-CMC-Control and 3D-CMC-SAC groups. While control cells were incubated under standard culture conditions, cells in the SAC groups were incubated with the IC50 dose (50 µM for both the 2D-SAC C6 and 3D-CMC-SAC groups) of SAC in culture medium for 24 and 48 hours. Thereafter, all groups were stained with antibodies recognizing NOTCH1 and JAGGED1, and the mRNA expression levels of NOTCH1 and JAGGED1 were evaluated by qRT-PCR. Increasing doses of SAC were administered for 24 hours in the C6 glioma cell line. The concentration of 50 μM was chosen as the most suitable dose for administration. The gene expression profiles were different in the two forms of culture. NOTCH1 receptor mRNA expression levels were significantly decreased in cells treated with 50 μM SAC for 24 hours compared to control cells in both the two-dimensional (2D) and three-dimensional (3D) cell cultures. The immunoreactivities of both of these markers (JAGGED1 and NOTCH1) were significantly decreased in the glioma cells in the SAC group compared to the control group. This study shows that SAC has potential as a drug for human use, as indicated by its nontoxic nature. The present study confirmed the anticancer activity of SAC by modulating NOTCH1 and JAGGED1 signaling in glioma cancer cells.

Targeted gene delivery to the brain using CDX-modified chitosan nanoparticles.

Introduction: Blood-brain barrier with strictly controlled activity participates in a coordinated transfer of bioactive molecules from the blood to the brain. Among different delivery approaches, gene delivery is touted as a promising strategy for the treatment of several nervous system disorders. The transfer of exogenous genetic elements is limited by the paucity of suitable carriers. As a correlate, designing high-efficiency biocarriers for gene delivery is challenging. This study aimed to deliver pEGFP-N1 plasmid into the brain parenchyma using CDX-modified chitosan (CS) nanoparticles (NPs). Methods: Herein, we attached CDX, a 16 amino acids peptide, to the CS polymer using bifunctional polyethylene glycol (PEG) formulated with sodium tripolyphosphate (TPP), by ionic gelation method. Developed NPs and their nanocomplexes with pEGFP-N1 (CS-PEG-CDX/pEGFP) were characterized using DLS, NMR, FTIR, and TEM analyses. For in vitro assays, a rat C6 glioma cell line was used for cell internalization efficiency. The biodistribution and brain localization of nanocomplexes were studied in a mouse model after intraperitoneal injection using in vivo imaging and fluorescent microscopy. Results: Our results showed that CS-PEG-CDX/pEGFP NPs were uptaken by glioma cells in a dose-dependent manner. In vivo imaging revealed successful entry into the brain parenchyma indicated with the expression of green fluorescent protein (GFP) as a reporter protein. However, the biodistribution of developed NPs was also evident in other organs especially the spleen, liver, heart, and kidneys. Conclusion: Based on our results, CS-PEG-CDX NPs can provide a safe and effective nanocarrier for brain gene delivery into the central nervous system (CNS).

Apoptotic Effect of Novel Benzimidazole Derivatives Bearing Pyridyl/Pyrimidinyl Piperazine Moiety.

Benzimidazole derivatives bearing pyridyl/pyrimidinyl piperazine moiety has attracted attention in medicinal chemistry and modern drug discovery since it exhibited a variety of biological activities, including anticancer activity. In this study, we designed and synthesized novel 1-[2-oxo-2-(4-substituted phenyl)ethyl]benzimidazol-2- yl)methyl 4-(2-pyridyl/pyrimidin-2-yl)piperazine-1-carbodithioate derivatives (2a-m). We also investigated their anticancer activities against A549 lung adenocarcinoma and C6 rat glioma cell lines. We further studied the selectivity of the compounds against the NIH/3T3 mouse embryonic fibroblast cell line. Cholinesterase inhibition effects of these compounds were also investigated to measure the relationship between anticancer activity and cholinesterases. The cytotoxic activities of these acquired thirteen final compounds were screened using MTT assay on A549, C6, and NIH/3T3 cell lines. Cell proliferation ELISA, BRDU (colorimetric) assay was used to measure the proliferation in replicative cells in which DNA synthesis occurs. Flow cytometric analysis was used to measure apoptotic cell percentages, caspase 3 activity, and mitochondrial membrane depolarised cell percentages. Compounds 2e, 2f, and 2k were shown to be the most active antitumor agents with selective cytotoxicities (the results for A549 were 76.58±6.43, 55.13±5.75, and 32.94±3.02 μM, respectively; and for C6 they were 86.48±3.60, 97.12±30.21, and 59.29±3.95 μM, respectively), high DNA synthesis inhibition rates and high apoptotic cell percentages on both cell lines. The results showed that compounds 2e, 2f, and 2k have potential anticancer activity against A549 and C6 cell lines.

Effects of Taheri Consciousness Fields on the Rat C6 Glioma Cell Line

The most common primary spinal cord and brain tumors are gliomas, representing 81% of malignant brain tumors. In neuro-oncology investigations, the rat C6 glioma cell line has mostly been utilized as an experimental model system. Taheri Consciousness Fields (TCFs) founded and introduced by Mohammad Ali Taheri, are novel fields that are neither matter nor energy. Therefore, they are non-quantifiable and cannot be directly observed or measured. However, it is possible to demonstrate and measure the effects of these fields through standard scientific experiments. This study aimed to evaluate the effect of TCFs (A and B) on the C6 glioma cell line in three and four treatments compared with the control (nono-treatment) group. To study morphology and microscopic properties of the cells, cells were detached and stained with trypan blue then the dead cells were counted. An MTT assay was used in order to evaluate the effect of TCFs. The expression of Bax and Bcl-2 genes was assessed by using the RT Real-time PCR. The results showed that the TCFs treatment not only reduced the number of the C6 glioma cells but also changed their morphology. Similarly, in the trypan blue dye count, more dead cells were counted in the TCFs groups in comparison to the control group. In the MTT assay, both TCFs displayed a cytotoxic effect in incubation times on the C6 glioma cells (p&lt; 0.05). Bax/Bcl2 ratio increased to 3.5 and 7-fold, compared to the control via TCF (A), and (B), respectively (P&lt;0.05). The findings suggest that TCF (A) and (B) can induce apoptosis in the rat C6 glioma cells. The TCF (B) effect was greater than the effect of TCF (A) in all tests. The mechanism of action of TCFs is still not definable by researchers, and it can be useful to elucidate the effects of the TCFs treatment in vivo and in clinical research.

Antineoplastic Activity In Vitro of 2-amino-5-benzylthiasol Derivative in the Complex with Nanoscale Polymeric Carriers

The main problems of contemporary chemotherapy are the insufficient efficacy of antitumor drugs and low selectivity of their action, development of multidrug resistance, and poor water solubility of antitumor drugs. One of the ways to improve the targeted delivery of drugs and increase their solubility is the use of polymeric nanoscale carriers. The newly synthesized thiazole derivative (N-(5-benzyl-1,3-thiazol-2-yl)-3,5-dimethyl-1-benzofuran-2-carboxamide, BF1) is cytotoxic in its activity towards some tumor cell lines. The aim of this study was to investigate the action of BF1 conjugated with novel polymeric carriers based on polyethylene glycol (PEG). The synthesized complexes exhibited a higher level of cytotoxicity towards specific tumor cell lines than the pure (unconjugated) thiazole derivative or/and doxorubicin (positive control). Complexes 4, 14 and 8, 18 were the most toxic to the human hepatocarcinoma HepG2 and the rat glioma C6 cell lines. Complex 6 exhibited a high level of toxicity towards human glioblastoma T98G and human promyelocytic leukemia HL-60 cell lines. Thus, complexes 4 and 14 based on poly(VEP-co-GMA)-graft-mPEG, complex 6 based on poly(PEGMA), and complexes 8 and 18 based on poly(PEGMA-co-DMM) selectively increase the toxic action of thiazole derivative BF1 towards tumor cells.

The effect of low doses of doxorubicin on the rat glioma C6 cells in the context of the proteins involved in intercellular interactions

The aim of this investigation was to determine the effect of doxorubicin on F–actin rearrangement and β–catenin and cofilin–1 in a rat glioma C6 cell line in combination with changes in their morphology and ultrastructure. The experimental material constituted rat glioma C6 cell line. The cells were incubated with sublethal doses of doxorubicin in the concentration of 50, 100 and 200 nM. The blue trypan dye method was used to determine the number of dead cells. Morphological and ultrastructural changes in the cells were evaluated using light and transmission electron microscope, respectively. In order to determine the rearrangements and level of expression of F–actin, β–catenin and cofilin–1 they were analyzed using a fluorecence microscope. In turn, cell death and cell cycle were evaluated by Guava 6HT–2 L Cytometer. The performed experiments showed a dose–dependent decrease in the survival of C6 cells after treatment with doxorubicin. The analysis of cell death showed a dose–dependent increase in the population of apoptotic and necrotic cells. These results were confirmed by microscopy observation. The changes in morphology, ultrastructure, and rearrangements of F–actin, β–catenin and cofilin–1 were also observed. The results obtained in the study showed that sublethal concentrations of doxorubicin influenced the structure of F–actin and other proteins involved in cell–cell interactions. Moreover, mitotic catastrophe may preceding apoptosis, what suggest the cytotoxic effect of low dose of doxorubicin. Furthermore, our results confirmed the multi–dimensional mechanism of DOX action in tumor cells.

The selective lipoprotein-associated phospholipase A2 inhibitor darapladib triggers irreversible actions on glioma cell apoptosis and mitochondrial dysfunction

Although the development of a therapeutic strategy for glioblastoma multiforme (GBM), the most aggressive type of brain tumor in adults, is in progress, the prognosis is still limited. In this study, we evaluated the anti-glioma effects of darapladib, a selective reversible inhibitor of lipoprotein-associated phospholipase A2 (Lp-PLA2) that is encoded by the PLA2G7 gene and serves as a predictive biomarker of sub-clinical inflammation in cardiovascular diseases. The three glioma cell lines (rat C6 glioma cell line, human U87MG, and human U251MG) and an ex vivo brain tissue slice-glioma cell co-culture system were used to validate the inhibitory effect of darapladib on the expansion of glioma cells. Exposure to darapladib at doses higher than 5 μM induced profound cytotoxicity in C6, U87MG, and U251MG. Moreover, the colony formation ability of the glioma cell lines was significantly repressed after the addition of darapladib. Although darapladib did not reduce the generation of the Lp-PLA2 downstream molecule, arachidonic acid (AA), in the glioma cells, this small compound triggered mitochondrial membrane depolarization and cell apoptosis in these glioma cells. In addition, transient exposure to darapladib induced the upregulation of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) levels, but reduced phosphorylation of AKT/PKB (protein kinase B). The results from an ex vivo brain slice culture system further confirmed the effective inhibition of darapladib on the expansion of glioma cells. In conclusion, darapladib acts as a potential anti-glioma compound via the induction of mitochondrial membrane depolarization and cell apoptosis, and the inhibition of AKT signaling in glioma cells.

Antiglioma Activity of Aryl and Amido-Aryl Acetamidine Derivatives Targeting iNOS: Synthesis and Biological Evaluation.

Nitric oxide is an important inflammation mediator with a recognized role in the development of different cancers. Gliomas are primary tumors of the central nervous system with poor prognosis, and the expression of the inducible nitric oxide synthase correlates with the degree of malignancy, changes in vascular reactivity, and neo-angiogenesis. Therefore, targeting the nitric oxide biosynthesis appears as a potential strategy to impair glioma progression. In the present work a set of aryl and amido-aryl acetamidine derivatives were synthesized to obtain new potent and selective inducible nitric oxide synthase inhibitors with improved physicochemical parameters with respect to the previously published molecules. Compound 17 emerged as the most promising inhibitor and was evaluated on C6 rat glioma cell line, showing antiproliferative effects and high selectivity over astrocytes.

The pivotal role of micro-environmental cells in a human blood\u2013brain barrier in vitro model of cerebral ischemia: functional and transcriptomic analysis

BackgroundThe blood–brain barrier (BBB) is altered in several diseases of the central nervous system. For example, the breakdown of the BBB during cerebral ischemia in stroke or traumatic brain injury is a hallmark of the diseases’ progression. This functional damage is one key event which is attempted to be mimicked in in vitro models. Recent studies showed the pivotal role of micro-environmental cells such as astrocytes for this barrier damage in mouse stroke in vitro models. The aim of this study was to evaluate the role of micro-environmental cells for the functional, paracellular breakdown in a human BBB cerebral ischemia in vitro model accompanied by a transcriptional analysis.MethodsTranswell models with human brain endothelial cell line hCMEC/D3 in mono-culture or co-culture with human primary astrocytes and pericytes or rat glioma cell line C6 were subjected to oxygen/glucose deprivation (OGD). Changes of transendothelial electrical resistance (TEER) and FITC-dextran 4000 permeability were recorded as measures for paracellular tightness. In addition, qPCR and high-throughput qPCR Barrier chips were applied to investigate the changes of the mRNA expression of 38 relevant, expressed barrier targets (tight junctions, ABC-transporters) by different treatments.ResultsIn contrast to the mono-culture, the co-cultivation with human primary astrocytes/pericytes or glioma C6 cells resulted in a significantly increased paracellular permeability after 5 h OGD. This indicated the pivotal role of micro-environmental cells for BBB breakdown in the human model. Hierarchical cluster analysis of qPCR data revealed differently, but also commonly regulated clustered targets dependent on medium exchange, serum reduction, hydrocortisone addition and co-cultivations.ConclusionsThe co-cultivation with micro-environmental cells is necessary to achieve a functional breakdown of the BBB in the cerebral ischemia model within an in vivo relevant time window. Comprehensive studies by qPCR revealed that distinct expression clusters of barrier markers exist and that these are regulated by different treatments (even by growth medium change) indicating that controls for single cell culture manipulation steps are crucial to understand the observed effects properly.

Gastrodin Inhibits H2O2-Induced Ferroptosis through Its Antioxidative Effect in Rat Glioma Cell Line C6.

Ferroptosis is a form of necrosis caused by iron-induced accumulation of lipid hydroperoxide, involving several molecular events, and has been implicated in Parkinson's disease. Gastrodin is a component of Gastrodia elata Blume with strong antioxidant activity. We examined whether gastrodin can prevent H2O2-induced cytotoxicity in rat glioma cell line C6. For this purpose, C6 cells were pretreated with gastrodin (1, 5, 25 µM) and then exposed to 100 µM H2O2. Results showed that pretreatment of C6 cells with gastrodin decreased H2O2-induced lactate dehydrogenase (LDH) release and cell death. Moreover, gastrodin decreased intracellular malondialdehyde (MDA) level, whereas increased glutathione peroxidase (GPX) activity and glutathione (GSH) level after H2O2 treatment. In addition, treatment of deferoxamine (DFO), ferrostatin-1, and liproxstatin-1 abolished ferroptosis induced by H2O2 or erastin pretreatment. Treatment with gastrodin attenuated H2O2-induced ferroptosis and decreased lipid reactive oxygen species (ROS) (C11-BODIPY) production in C6 cells. Moreover, gastrodin increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2), GPX4, ferroportin-1 (FPN1), and heme oxygenase-1 (HO-1) in C6 cells treated with H2O2. RSL3, a GPX4 inhibitor, inhibited GPX4 protein level in cells co-treated with gastrodin and 100 µM H2O2. These findings indicate that gastrodin can inhibit H2O2-induced ferroptosis through its antioxidative effect in C6 cells.