stilbenes and Glioma

Topics: Animals; Central Nervous System Diseases; Glioma; Humans; NF-kappa B; Signal Transduction; Stilbenes

There is growing interest in dietary phytochemicals as potential cancer chemopreventive agents. Resveratrol (3,4',5-trihydroxy-trans-stilbene), a naturally occurring phytoalexin that is present in grapes, red wine, berries and peanuts, has been studied extensively for its ability to interfere with multistage carcinogenesis. Resveratrol is known to have antioxidant, anti-inflammatory and antiproliferative effects on a variety of cancer cells in vitro and in various animal models. However, the effect(s) of resveratrol in vivo on humans are still controversial. This study discusses current knowledge with regard to the effects of resveratrol in relation to its potential as a chemopreventive and/or chemotherapeutic molecule against human gliomas.

Topics: Antineoplastic Agents; Brain Neoplasms; Glioma; Humans; Resveratrol; Ribonucleotide Reductases; Stilbenes

The schweinfurthin family of natural compounds exhibit a unique and potent differential cytotoxicity against a number of cancer cell lines and may reduce tumor growth in vivo. In some cell lines, such as SF-295 glioma cells, schweinfurthins elicit cytotoxicity at nanomolar concentrations. However, other cell lines, like A549 lung cancer cells, are resistant to schweinfurthin treatment up to micromolar concentrations. At this time, the precise mechanism of action and target for these compounds is unknown. Here, we employ RNA sequencing of cells treated with 50 nM schweinfurthin analog TTI-3066 for 6 and 24 h to elucidate potential mechanisms and pathways which may contribute to schweinfurthin sensitivity and resistance. The data was analyzed via an interaction model to observe differential behaviors between sensitive SF-295 and resistant A549 cell lines. We show that metabolic and stress-response pathways were differentially regulated in the sensitive SF-295 cell line as compared with the resistant A549 cell line. In contrast, A549 cell had significant alterations in response genes involved in translation and protein metabolism. Overall, there was a significant interaction effect for translational proteins, RNA metabolism, protein metabolism, and metabolic genes. Members of the Hedgehog pathway were differentially regulated in the resistant A549 cell line at both early and late time points, suggesting a potential mechanism of resistance. Indeed, when cotreated with the Smoothened inhibitor cyclopamine, A549 cells became more sensitive to schweinfurthin treatment. This study therefore identifies a key interplay with the Hedgehog pathway that modulates sensitivity to the schweinfurthin class of compounds.

Topics: A549 Cells; Antineoplastic Agents, Phytogenic; Brain Neoplasms; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Energy Metabolism; Euphorbiaceae; Gene Expression Regulation, Neoplastic; Glioma; Hedgehog Proteins; Humans; Lung Neoplasms; Prenylation; RNA-Seq; Signal Transduction; Stilbenes; Transcription, Genetic; Transcriptome

Combretastatin A-4 (CA4), a tubulin inhibitor, binds to the colchicine site of tubulin, inhibits tubulin polymerization, and leads to the apoptosis of tumor cells. However, the poor hydrophilicity and blood-brain barrier (BBB) penetration ability of CA4 hampers its application in the treatment of glioma. In this study, a novel combretastatin A-4 derivative (CA4D) was designed and developed, which was further conjugated with glucose via disulfide-bond-bridged (CA4D-SS-Glu) to enhance the BBB penetration capacity. The obtained CA4D-SS-Glu conjugate displayed a suitable water partition coefficient and the superior ability across BBB in vitro and in vivo. In addition, the CA4D-SS-Glu exhibited rapid redox-responsive drug release in the presence of glutathione, enhanced in vitro cytotoxicity, and cell apoptosis. Our data further confirmed that CA4D-SS-Glu inhibited proliferation, and restrained migration via affecting microtubule stabilization. Additionally, the conjugate also showed the highest antiproliferative and antitumor action on glioma in vivo as compared to CA4D and CA4. Taken together, the novel CA4D-SS-Glu conjugate possess improved physicochemical property and BBB penetration ability, reduction triggered release of CA4D, and efficient antiproliferative activity. These results provided a novel and effective entry to the treatment of glioma.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Glioma; Humans; Oxidation-Reduction; Stilbenes; Tubulin Modulators

Glioma is the most general primary and lethal intracranial malignant tumor. Pterostilbene (PTE), an analog of stilbene and resveratrol, has attracted attention in recent years due to its significant antitumor activity in multiple solid tumors; however, its effect on drug-resistant glioma cells and the underlying mechanism have not yet been reported. In this study, we found that pterostilbene inhibited proliferation, induced intrinsic mitochondria-mediated apoptosis and caused S phase arrest, inhibited migration and excessive invasion in glioma cells. Pretreatment with the pan-caspase-inhibitor Z-VAD-FMK attenuated the PTE-induced apoptosis of glioma cells. Moreover, PTE significantly increased the production of reactive oxygen species (ROS) and reduce the mitochondrial membrane potential (MMP). Inhibition of ROS with N-acetyl-L-cysteine not only rescued PTE-induced reduction of cellular viability but also prevented glioma cell apoptosis. We also discovered ERK 1/2 and JNK signaling pathways were activated by PTE and contributed to induce glioma cell apoptosis. In addition, specific inhibitors of ERK 1/2 and JNK attenuated PTE-induced apoptosis. Besides, PTE significantly reduced tumor volume and prolonged median survival of tumor-bearing rats in vivo. In summary, the results of this study indicate that the anti-tumor effect of PTE on glioma cells may provide a new treatment option for glioma patients.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Gene Expression Regulation, Neoplastic; Glioma; Humans; MAP Kinase Signaling System; Membrane Potential, Mitochondrial; Mitochondria; Rats; Reactive Oxygen Species; Stilbenes; Xenograft Model Antitumor Assays

Topics: Adult; Aged; Amyloid; Aniline Compounds; Apolipoprotein E4; Brain; Brain Neoplasms; Chemoradiotherapy; Cognition; Cognition Disorders; Cohort Studies; Female; Glioma; Heterozygote; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Pilot Projects; Positron-Emission Tomography; Radiopharmaceuticals; Radiotherapy, Conformal; Stilbenes

The use of an optical resolution photoacoustic microscopy (OR-PAM) system to evaluate the vascular disruptive effect of combretastatin A4 Phosphate (CA4P) on a murine orthotopic glioma with intact skull is described here. Second generation optical-resolution photoacoustic microscopy scanner with a 532 nm pulsed diode-pumped solid-state laser that specifically matches the absorption maximum of hemoglobin in tissues was used to image orthotopic glioma inoculated in mouse brain. Two-dimensional maps of brain vasculature with a lateral resolution of 5 μm and a depth of 700 μm at a field of view 5 × 4 mm were acquired on normal brain and glioma brain. Longitudinal imaging of the brain pre- and post-administration of CA4P, a FDA approved drug for solid tumors, enabled the monitoring of hemodynamic changes in tumor vasculature revealing the well documented vascular shutdown and recovery associated with this drug. Our study marks the beginning of potential prospects of this technology as an imaging tool for preclinical and clinical study of pathologies characterized by changes in the vasculature.

Topics: Animals; Blood Vessels; Brain Neoplasms; Cell Line, Tumor; Cell Transformation, Neoplastic; Female; Glioma; Humans; Mice; Microscopy; Neovascularization, Pathologic; Photoacoustic Techniques; Stilbenes

Understanding the uptake of a drug by diseased tissue, and the drug's subsequent spatiotemporal distribution, are central factors in the development of effective targeted therapies. However, the interaction between the pathophysiology of diseased tissue and individual therapeutic agents can be complex, and can vary across tissue types and across subjects. Here, we show that the combination of mathematical modelling, high-resolution optical imaging of intact and optically cleared tumour tissue from animal models, and in vivo imaging of vascular perfusion predicts the heterogeneous uptake, by large tissue samples, of specific therapeutic agents, as well as their spatiotemporal distribution. In particular, by using murine models of colorectal cancer and glioma, we report and validate predictions of steady-state blood flow and intravascular and interstitial fluid pressure in tumours, of the spatially heterogeneous uptake of chelated gadolinium by tumours, and of the effect of a vascular disrupting agent on tumour vasculature.

Topics: Animals; Antineoplastic Agents; Blood Vessels; Cell Line, Tumor; Colorectal Neoplasms; Contrast Media; Diphosphates; Disease Models, Animal; Female; Gadolinium; Glioma; Humans; Hydrodynamics; Image Processing, Computer-Assisted; Mice; Mice, Inbred C57BL; Mice, Nude; Models, Theoretical; Regional Blood Flow; Stilbenes; Transplantation, Heterologous

Topics: Adjuvants, Pharmaceutic; Animals; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Glioma; Humans; Membrane Potential, Mitochondrial; Rats; Resveratrol; Stilbenes; Tannins

The polyphenolic phytostilbene,

Topics: Animals; Apoptosis; Caspases; Cell Line, Tumor; Cytoprotection; DNA Damage; Enzyme Activation; Glioma; Models, Biological; Neurofibrillary Tangles; Oxidative Stress; Phosphorylation; Phosphoserine; Rats; Resveratrol; Signal Transduction; Stilbenes; Stress, Physiological; tau Proteins; Ultraviolet Rays

Glioblastoma multiforme (GBM) is a grade IV astrocytoma and the most common form of malignant brain tumor in adults. GBM remains one of the most fatal and least successfully treated solid tumors: current therapies provide a median survival of 12-15 months after diagnosis, due to the high recurrence rate. Glioma Stem Cells (GSCs) are believed to be the real driving force of tumor initiation, progression and relapse. Therefore, better therapeutic strategies GSCs-targeted are needed. Resveratrol is a polyphenolic phytoalexin found in fruits and vegetables displaying pleiotropic health benefits. Many studies have highlighted its chemo-preventive and chemotherapeutic activities in a wide range of solid tumors. In this work, we analyzed the effects of Resveratrol exposure on cell viability, proliferation and motility in seven GSC lines isolated from GBM patients. For the first time in our knowledge, we investigated Resveratrol impact on Wnt signaling pathway in GSCs, evaluating the expression of seven Wnt signaling pathway-related genes and the protein levels of c-Myc and β-catenin. Finally, we analyzed Twist1 and Snail1 protein levels, two pivotal activators of epithelial-mesenchymal transition (EMT) program. Results showed that although response to Resveratrol exposure was highly heterogeneous among GSC lines, generally it was able to inhibit cell proliferation, increase cell mortality, and strongly decrease cell motility, modulating the Wnt signaling pathway and the EMT activators. Treatment with Resveratrol may represent a new interesting therapeutic approach, in order to affect GSCs proliferation and motility, even if further investigations are needed to deeply understand the GSCs heterogeneous response.

Topics: beta Catenin; Brain Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Epithelial-Mesenchymal Transition; Glioma; Humans; Neoplastic Stem Cells; Proto-Oncogene Proteins c-myc; Resveratrol; Stilbenes; Wnt Signaling Pathway

POK erythroid myeloid ontogenic factor (Pokemon), an important proto-oncoprotein, is a transcriptional repressor that regulates the expression of many genes and plays an important role in tumorigenesis. Resveratrol (RSV), a natural polyphenolic compound, has many beneficial biological effects on health. In this study, we investigated the role of Pokemon in RSV-induced biological effects and the effect of RSV on the expression of Pokemon in glioma cells. We found that overexpression of Pokemon decreased RSV-induced cell apoptosis, senescence, and anti-proliferative effects. Moreover, we showed that RSV could efficiently decrease the activity of the Pokemon promoter and the expression of Pokemon. Meanwhile, RSV also inhibited Sp1 DNA binding activity to the Pokemon promoter; whereas, it did not influence the expression and nuclear translocation of Sp1. In addition, we found that RSV could increase the recruitment of HDAC1, but decreased p300 to the Pokemon promoter. Taken together, all these results extended our understanding on the anti-cancer mechanism of RSV in glioma cells.

Topics: Apoptosis; Brain Neoplasms; Cell Line, Tumor; Cell Nucleus; Cell Proliferation; Cellular Senescence; DNA-Binding Proteins; DNA, Neoplasm; E1A-Associated p300 Protein; Gene Expression Regulation, Neoplastic; Glioma; HEK293 Cells; Histone Deacetylase 1; Humans; Promoter Regions, Genetic; Protein Binding; Protein Transport; Resveratrol; Sp1 Transcription Factor; Stilbenes; Transcription Factors

Like the anti-angiogenic strategy, anti-vascular mimicry is considered as a novel targeting strategy for glioma. In the present study, we used NGR as a targeting ligand and prepared NGR-modified liposomes containing combretastatin A4 (NGR-SSL-CA4) in order to evaluate their potential targeting of glioma tumor cells and vasculogenic mimicry (VM) formed by glioma cells as well as their anti-VM activity in mice with glioma tumor cells. NGR-SSL-CA4 was prepared by a thin-film hydration method. The in vitro targeting of U87-MG (human glioma tumor cells) by NGR-modified liposomes was evaluated. The in vivo targeting activity of NGR-modified liposomes was tested in U87-MG orthotopic tumor-bearing nude mice. The anti-VM activity of NGR-SSL-CA4 was also investigated in vitro and in vivo. The targeting activity of the NGR-modified liposomes was demonstrated by in vitro flow cytometry and in vivo biodistribution. The in vitro anti-VM activity of NGR-SSL-CA4 was indicated in a series of cell migration and VM channel experiments. NGR-SSL-CA4 produced very marked anti-tumor and anti-VM activity in U87-MG orthotopic tumor-bearing mice in vivo. Overall, the NGR-SSL-CA4 has great potential in the multi-targeting therapy of glioma involving U87-MG cells, and the VM formed by U87-MG cells as well as endothelial cells producing anti-U87-MG cells, and anti-VM formed by U87-MG cells as well as anti-endothelial cell activity.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Brain; Brain Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Endothelial Cells; Flow Cytometry; Glioma; Humans; Kaplan-Meier Estimate; Liposomes; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Multiple Chronic Conditions; Neovascularization, Pathologic; Oligopeptides; Optical Imaging; Stilbenes; Tissue Distribution; Xenograft Model Antitumor Assays

Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson disease (PD), with accumulating evidence that prefibrillar oligomers and protofibrils are the pathogenic species in PD and related synucleinopathies. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a key regulator of mitochondrial biogenesis and cellular energy metabolism, has recently been associated with the pathophysiology of PD. Despite extensive effort on studying the function of PGC-1α in mitochondria, no studies have addressed whether PGC-1α directly influences oligomerization of α-syn or whether α-syn oligomers impact PGC-1α expression.. We tested whether pharmacological or genetic activation of PGC-1α or PGC-11α knockdown could modulate the oligomerization of α-syn in vitro by using an α-syn -fragment complementation assay.. In this study, we found that both PGC-1α reference gene (RG-PGC-1α) and the central nervous system (CNS)-specific PGC-1α (CNS-PGC-1α) are downregulated in human PD brain, in A30P α-syn transgenic animals, and in a cell culture model for α-syn oligomerization. Importantly, downregulation of both RG-PGC-1α and CNS-PGC-1α in cell culture or neurons from RG-PGC-1α-deficient mice leads to a strong induction of α-syn oligomerization and toxicity. In contrast, pharmacological activation or genetic overexpression of RG-PGC-1α reduced α-syn oligomerization and rescued α-syn-mediated toxicity.. Based on our results, we propose that PGC-1α downregulation and α-syn oligomerization form a vicious circle, thereby influencing and/or potentiating each other. Our data indicate that restoration of PGC-1α is a promising approach for development of effective drugs for the treatment of PD and related synucleinopathies.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Animals; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Embryo, Mammalian; Enzyme Inhibitors; Female; Gene Expression Regulation; Glioma; Humans; Macrolides; Male; Mice; Mice, Transgenic; Middle Aged; Neurons; Parkinson Disease; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; PPAR gamma; Resveratrol; RNA Polymerase II; Stilbenes; Substantia Nigra; TATA-Box Binding Protein; Transcription Factors

Long non-coding RNAs (lncRNAs), a recently discovered class of non-coding genes, are transcribed throughout the genome. Emerging evidence suggests that lncRNAs may be involved in modulating various aspects of tumor biology, including regulating gene activity in response to external stimuli or DNA damage. No data are available regarding the expression of lncRNAs during genotoxic stress-induced apoptosis and/or necrosis in human glioma cells. In this study, we detected a change in the expression of specific candidate lncRNAs (neat1, GAS5, TUG1, BC200, Malat1, MEG3, MIR155HG, PAR5, and ST7OT1) during DNA damage-induced apoptosis in human glioma cell lines (U251 and U87) using doxorubicin (DOX) and resveratrol (RES). We also detected the expression pattern of these lncRNAs in human glioma cell lines under necrosis induced using an increased dose of DOX. Our results reveal that the lncRNA expression patterns are distinct between genotoxic stress-induced apoptosis and necrosis in human glioma cells. The sets of lncRNA expressed during genotoxic stress-induced apoptosis were DNA-damaging agent-specific. Generally, MEG3 and ST7OT1 are up-regulated in both cell lines under apoptosis induced using both agents. The induction of GAS5 is only clearly detected during DOX-induced apoptosis, whereas the up-regulation of neat1 and MIR155HG is only found during RES-induced apoptosis in both cell lines. However, TUG1, BC200 and MIR155HG are down regulated when necrosis is induced using a high dose of DOX in both cell lines. In conclusion, our findings suggest that the distinct regulation of lncRNAs may possibly involve in the process of cellular defense against genotoxic agents.

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; DNA Damage; Doxorubicin; Glioma; Humans; Necrosis; Resveratrol; RNA, Long Noncoding; Stilbenes

Resveratrol (Res), a natural polyphenolic compound, has anticancer activity in a variety of cancers. In the present study, the antitumor effect and underlying molecular mechanism of Res on rat C6 glioma growth was studied. The results demonstrated that Res inhibited glioma cell proliferation, arrested cell cycle in S phase and induced apoptosis in vitro. Res also suppressed intracranial C6 tumor growth in vivo and prolonged survival in a fraction of the rats bearing intracranial gliomas. Res significantly downregulated the specific miRs, including miR-21, miR-30a-5p and miR-19, which have been identified as oncomiRs in our previous studies, and altered the expression of their targeting and crucial genes for glioma formation and progression such as p53, PTEN, EGFR, STAT3, COX-2, NF-κB and PI3K/AKT/mTOR pathway. Therefore, the anti-glioma effect of Res, at least in part, is through the regulation of oncogenic miRNAs. The effect of Res on non-coding RNAs should be studied further. Res is a potential multi-targeting drug for the treatment of gliomas.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Glioma; MicroRNAs; Rats; Resveratrol; Signal Transduction; Stilbenes; Xenograft Model Antitumor Assays

Glioblastoma multiforme (GBM) is the most aggressive type characterized by relapse and resistance even with the combination of radio- and chemotherapy. The presence of glioma stem cells (GSCs) has been shown to contribute to tumorigenesis, recurrence and treatment resistance. Particularly, CD133-positive glioma cells have been shown to represent the subpopulation that confers glioma radioresistance and suggested to be the source of tumor recurrence after radiation. Thus, a better understanding and the development of agents which target GSCs could potentially lead to a significant improvement in treating GBM patients. Here, we demonstrated that GRP78 (an antistress protein) was highly expressed in GBM cells along with β-catenin and Notch and correlated to the development of GSCs. CD133+ GSCs exhibited enhanced migration/invasion and self-renewal abilities. When GRP78 was silenced, GSC properties were suppressed and the sensitivity towards irradiation increased. In addition, the level of microRNA 205 appeared to be negatively associated with GRP78 expression. Our previous study indicated that pterostilbene (PT) possessed anticancer stem cell properties in hepatocellular carcinoma. Thus, we examined whether PT is also effective against GSCs. We found that PT-treated GSCs exhibited suppressed self-renewal and irradiation-resistant abilities. PT-mediated effects were associated with an increase of miR-205. Finally, we showed that PT treatment suppressed tumorigenesis in GSC xenograft mice. In conclusion, we provided evidence that GRP78/miR-205 axis played an important role in GSC maintenance and irradiation resistance. PT treatment suppressed GSC development via negatively modulating GRP78 signaling. PT may be considered for combined therapeutic agent to enhance irradiation efficacy in GBM patients.

Topics: Animals; Brain Neoplasms; Endoplasmic Reticulum Chaperone BiP; Female; Glioma; Heat-Shock Proteins; Heterografts; Humans; Mice, Inbred NOD; Mice, SCID; MicroRNAs; Neoplastic Stem Cells; Pterocarpus; Radiation Tolerance; Stilbenes

Tristetraprolin (TTP) is an AU-rich elements (AREs)-binding protein, which regulates the decay of AREs-containing mRNAs such as proto-oncogenes, anti-apoptotic genes and immune regulatory genes. Despite the low expression of TTP in various human cancers, the mechanism involving suppressed expression of TTP is not fully understood. Here, we demonstrate that Resveratrol (3,5,4'-trihydroxystilbene, Res), a naturally occurring compound, induces glioma cell apoptosis through activation of tristetraprolin (TTP). Res increased TTP expression in U87MG human glioma cells. Res-induced TTP destabilized the urokinase plasminogen activator and urokinase plasminogen activator receptor mRNAs by binding to the ARE regions containing the 3' untranslated regions of their mRNAs. Furthermore, TTP induced by Res suppressed cell growth and induced apoptosis in the human glioma cells. Because of its regulation of TTP expression, these findings suggest that the bioactive dietary compound Res can be used as a novel anti-cancer agent for the treatment of human malignant gliomas.

Topics: 3' Untranslated Regions; Apoptosis; AU Rich Elements; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Fibroblasts; Gene Expression Regulation; Glioma; Humans; Receptors, Urokinase Plasminogen Activator; Resveratrol; RNA Stability; RNA, Messenger; Stilbenes; Tristetraprolin; Up-Regulation; Urokinase-Type Plasminogen Activator

Cellular senescence is an irreversible block of cellular division, and induction of senescence is being considered for treatment of many cancer types, mainly those resistant to classical pro-apoptotic therapies. Resveratrol (Rsv) and quercetin (Quer), two natural polyphenols, are able to induce senescence in different cancer models, including gliomas, the most common and aggressive primary brain tumor. These polyphenols modulate the activity of several proteins involved in cell growth and death in cancer cells, including histone deacetylases (HDAC), but the role of HDAC in senescence induced by Rsv and Quer is unclear. The HDAC inhibitor sodium butyrate (NaB) potentiated the pro-senescent effect of Rsv and Quer in human and rat glioma cell lines but not in normal rat astrocytes. Furthermore, the increment of Quer-induced senescence by NaB was accompanied by an increase of reactive oxygen species levels and an increment of the number of cells with nuclear abnormalities. Altogether, these data support a positive role of HDAC inhibition on the senescence induced by these polyphenols, and therefore co-treatment of HDAC inhibitors and polyphenols emerges as a potential alternative for gliomas.

Topics: Animals; Antineoplastic Agents; Butyric Acid; Cell Line, Tumor; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p21; Drug Screening Assays, Antitumor; Drug Synergism; Glioma; Histone Deacetylase Inhibitors; Humans; Quercetin; Rats; Reactive Oxygen Species; Resveratrol; Stilbenes

The development of novel therapeutic strategies to treat gliomas remains critical as a result of the poor prognoses, inef-. ficient therapies and recurrence associated with these tumors. In this context, biodegradable nanoparticles are emerging as efficient drug delivery systems for the treatment of difficult-to-treat diseases such as brain tumors. In the current study, we evaluated the antiglioma effect of trans-resveratrol-loaded lipid-core nanocapsules (RSV-LNC) based on in vitro (C6 glioma cell line) and in vivo (brain-implanted C6 cells) models of the disease. In vitro, RSV-LNC decreased the viability of C6 glioma cells to a higher extent than resveratrol in solution. Interestingly, RSV-LNC treatment was not cytotoxic to hippocampal organotypic cultures, a model of healthy neural cells, suggesting selectivity for cancer cells. RSV-LNC induced losses in glioma cell viability through induction of apoptotic cell death, as assessed by Annexin-FITC/PI assay, which was preceded by an early arrest in the S and G1 phases of the cell cycle. In brain-implanted C6 tumors, treatment with RSV-LNC (5 mg/kg/day, i.p.) for 10 days promoted a marked decrease in tumor size and also reduced the incidence of some malignant tumor-associated characteristics, such as intratumoral hemorrhaging, intratumoral edema and pseudopalisading, compared to resveratrol in solution. Taken together, the results presented herein suggest that nanoencapsulation of resveratrol improves its antiglioma activity, thus providing a provocative foundation for testing the clinical usefulness of nanoformulations of this natural compound as a new chemotherapeutic strategy for the treatment of gliomas.

Topics: Animals; Apoptosis; Brain Neoplasms; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chemical Phenomena; Chemistry, Pharmaceutical; Disease Models, Animal; G1 Phase; Glioma; Hippocampus; Humans; Lipids; Male; Nanocapsules; Neoplasm Transplantation; Rats; Rats, Wistar; Resveratrol; S Phase; Solutions; Stilbenes; Tumor Burden

Glioblastoma is the most common and aggressive primary brain tumor. Glioma stem cells (GSCs) are relatively resistant to chemo-radiotherapy and are responsible for tumor progression and the recurrence of glioblastomas after conventional therapy. Thus, the control of the GSC population is considered key to realizing long-term survival of glioblastoma patients. Here, we identified that resveratrol significantly reduced the self-renewal and tumor-initiating capacity of patient-derived GSCs. Furthermore, resveratrol promoted Nanog suppression via proteasomal degradation, which was inhibited by MG132, a proteasome inhibitor. p53 activation is an important factor in Nanog suppression and treatment with resveratrol was also found to activate the p53/p21 pathway. Importantly, inhibition of Nanog by siRNA provoked inhibitory effects on both the self-renewal and tumor-forming capacity of GSCs. Our findings indicate that Nanog is an essential factor for the retention of stemness and may contribute to the resveratrol-induced differentiation of GSCs. Our results also suggest that targeting GSCs via the p53-Nanog axis, with resveratrol for instance, could be a therapeutic strategy against glioblastoma.

Topics: Animals; Brain Neoplasms; Cell Differentiation; Cell Line, Tumor; Gene Silencing; Glioma; Homeodomain Proteins; Humans; Male; Mice; Mice, Inbred BALB C; Nanog Homeobox Protein; Neoplastic Stem Cells; Proteasome Endopeptidase Complex; Resveratrol; RNA, Small Interfering; Signal Transduction; Stilbenes; Transfection; Tumor Suppressor Protein p53; Xenograft Model Antitumor Assays

Glioblastoma is one of the most malignant brain tumors with a poor prognosis. In this study, we examined the effects of transferrin (Tf)-modified poly ethyleneglycol-poly lactic acid (PEG-PLA) nanoparticles conjugated with resveratrol (Tf-PEG-PLA-RSV) to glioma therapy in vitro and in vivo. The cell viability of Tf-PEG-PLA-RSV on C6 and U87 glioma cells was determined by the MTT assay. In vivo biodistribution and antitumor activity were investigated in Brain glioma bearing rat model of C6 glioma by i.p. administration of RSV-polymer conjugates. We found that the average diameter of each Tf-PEG-PLA-RSV is around 150 nm with 32 molecules of Tf on surface. In vitro cytotoxicity of PEG-PLA-RSV against C6 and U87 cells was higher than that of free RSV, and further the modification of Tf enhanced the cytotoxicity of the RSV-polymer conjugates as a result of the increased cellular uptake of the RSV-modified conjugates by glioma cells. In comparison with free RSV, RSV conjugates could significantly decrease tumor volume and accumulate in brain tumor, which resulted in prolonging the survival of C6 glioma-bearing rats. These results suggest that Tf-NP-RSV had a potential of therapeutic effect to glioma both in vitro and in vivo and might be a potential candidate for targeted therapy of glioma and worthy of further investigation.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biological Transport; Brain; Cell Line, Tumor; Cell Proliferation; Drug Carriers; Glioma; Lactic Acid; Male; Molecular Targeted Therapy; Nanoparticles; Polyesters; Polyethylene Glycols; Polymers; Rats; Resveratrol; Stilbenes; Survival Analysis; Transferrin; Xenograft Model Antitumor Assays

The alkylating agent temozolomide (TMZ) is the major chemotherapeutic drug used clinically in the treatment of malignant gliomas. This study investigated the mechanism behind TMZ-induced cell death and the possibility that resveratrol might increase TMZ efficacy. TMZ induced both apoptotic cell death and cytoprotective autophagy through a reactive oxygen species (ROS) burst and extracellular signal-regulated kinase (ERK) activation, which was suppressed by resveratrol, resulting in a decrease in autophagy and an increase in apoptosis, suggesting that the ROS/ERK pathway plays a crucial role in the fate of cells after TMZ treatment. Isobolographic analysis indicated that the combination of TMZ and resveratrol has a synergistic effect. Moreover, an in vivo mouse xenograft study also showed that coadministration of resveratrol and TMZ reduced tumor volumes by suppressing ROS/ERK-mediated autophagy and subsequently inducing apoptosis. Taken together, our data indicate that TMZ-induced ROS/ERK-mediated autophagy protected glioma cells from apoptosis, and the combination of resveratrol with TMZ could improve the efficacy of chemotherapy for brain tumors.

Topics: Animals; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Brain Neoplasms; Cell Line, Tumor; Cell Survival; Dacarbazine; Drug Synergism; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Female; Glioma; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Phosphorylation; Reactive Oxygen Species; Resveratrol; Stilbenes; Temozolomide; Tumor Burden; Xenograft Model Antitumor Assays

Recently, we demonstrated that Resveratrol (RSV), a well known natural stilbene, is able to induce a delay in S progression with a concomitant increase in γH2AX expression in U87 glioma cells. Furthermore, we showed that it inhibits the ability of recombinant human topoisomerase IIα to decatenate kDNA in vitro. Because proliferating tumor cells express topoisomerases at high levels and these enzymes are important targets of some of the most successful anticancer drugs, we tested whether RSV is able to poison topoisomerase IIα in glioma cells. Then, we monitored the increase of micronuclei in RSV treated U87 cells as a consequence of the conversion of TOPOII/DNA cleavable complexes to permanent DNA damage. Finally, we assayed the ability of RSV in modulating the expression of target proteins involved in DNA damage signalling, namely ATR, ATM, Chk1, Chk2 and γH2AX. Through a molecular modelling here we show that RSV binds at the TOPOII/DNA interface thus establishing several hydrogen bonds. Moreover, we show that RSV poisons TOPOIIα so inducing DNA damage; ATM, Chk2 and γH2AX are involved in the DNA damage signalling after RSV treatment.

Topics: Antigens, Neoplasm; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Line, Tumor; Checkpoint Kinase 1; Checkpoint Kinase 2; DNA Damage; DNA Topoisomerases, Type II; DNA-Binding Proteins; Glioma; Histones; Humans; Models, Molecular; Protein Kinases; Protein Serine-Threonine Kinases; Resveratrol; Stilbenes; Topoisomerase II Inhibitors; Tumor Suppressor Proteins

Extracellular ATP plays a pivotal role as a signaling molecule in physiological and pathological conditions in the CNS. In several glioma cell lines, ATP is a positive factor for one or more characteristics important for the abnormal growth and survival of these cells. This work presents immunofluorescence and biochemical analyses suggesting that an aerobic metabolism, besides mitochondria, is located also on the plasma membrane of C6 glioma cells. An ATP synthesis coupled to oxygen consumption was measured in plasma membrane isolated from C6 cells, sensitive to common inhibitors of respiratory chain complexes, suggesting the involvement of a putative surface ATP synthase complex. Immunofluorescence imaging showed that Cytochrome c oxydase colocalized with WGA, a typical plasma membrane protein, on the plasma membrane of glioma cells. Cytochrome c oxydase staining pattern appeared punctuate, suggesting the intriguing possibility that the redox chains may be expressed in discrete sites on C6 glioma cell membrane. Data suggest that the whole respiratory chain is localized on C6 glioma cell surface. Moreover, when resveratrol, an ATP synthase inhibitor, was added to culture medium, a cytostatic effect was observed, suggesting a correlation among the ectopic ATP synthesis and the tumor growth. So, a potential direction for the design of new targets for future therapies may arise.

Topics: Adenosine Triphosphate; Aerobiosis; Animals; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Cell Respiration; Electron Transport Complex IV; Glioma; Nigericin; Oxidation-Reduction; Oximetry; Protein Transport; Proton-Translocating ATPases; Rats; Resveratrol; Spectrophotometry; Stilbenes; Subcellular Fractions; Wheat Germ Agglutinins

Resveratrol (3,4',5-trihydroxy-trans-stilbene), a polyphenol naturally occurring in grapes and other plants, has cancer chemo-preventive effects and therapeutic potential. Although resveratrol modulates multiple pathways in tumor cells, how resveratrol or its affected pathways converge on chromatin to mediate its effects is not known. Using glioma cells as a model, we showed here that resveratrol inhibited cell proliferation and induced cellular hypertrophy by transforming spindle-shaped cells to enlarged, irregular and flatten-shaped ones. We further showed that resveratrol-induced hypertrophic cells expressed senescence-associated-β-galactosidase, suggesting that resveratrol-induced cellular senescence in glioma cells. Consistent with these observations, we demonstrated that resveratrol inhibited clonogenic efficiencies in vitro and tumor growth in a xenograft model. Furthermore, we found that acute treatment of resveratrol inhibited mono-ubiquitination of histone H2B at K120 (uH2B) in breast, prostate, pancreatic, lung, brain tumor cells as well as primary human cells. Chronic treatment with low doses of resveratrol also inhibited uH2B in the resveratrol-induced senescent glioma cells. Moreover, we showed that depletion of RNF20, a ubiquitin ligase of histone H2B, inhibited uH2B and induced cellular senescence in glioma cells in vitro, thereby recapitulated the effects of resveratrol. Taken together, our results suggest that uH2B is a novel direct or indirect chromatin target of resveratrol and RNF20 plays an important role in inhibiting cellular senescence programs that are intact in glioma cells.

Topics: Animals; Anticarcinogenic Agents; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Gene Knockdown Techniques; Glioma; Histones; Humans; Mice; Mice, Nude; Resveratrol; Stilbenes; Ubiquitin-Protein Ligases; Ubiquitination; Xenograft Model Antitumor Assays

High invasiveness of glioma cells is one of the reasons that patients with malignant glioma have a poor prognosis. Resveratrol, a plant compound abundant in the peel of grapes, has been suggested as a potential cancer chemopreventive agent. Therefore, we investigated the effect of resveratrol on glioma cell invasion.. The effect of resveratrol on U373MG human glioma cell invasion was assessed by Matrigel assay and methylthiazoltetrazolium assay. Western blotting and reverse transcription-polymerase chain reaction were performed to elucidate the action mechanism of resveratrol.. Resveratrol reduced tumor necrosis factor (TNF)-α-induced U373MG human glioma cell invasion. In addition, resveratrol repressed nuclear factor kappa B (NF-κB) activation and down-regulated mRNA expression of urokinase plasminogen activator (uPA) and its receptor in TNF-α-treated glioma cells.. These findings suggest that resveratrol could prevent glioma cell invasion via inhibiting proteolysis of extracellular matrix.

Topics: Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Cell Survival; Collagen; Drug Combinations; Gene Expression Regulation, Neoplastic; Glioma; Humans; Laminin; Neoplasm Invasiveness; NF-kappa B; Proteoglycans; Receptors, Urokinase Plasminogen Activator; Resveratrol; RNA, Messenger; Stilbenes; Tumor Necrosis Factor-alpha; Urokinase-Type Plasminogen Activator

Resveratrol is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Sulforaphane belongs to the family of isothiocyanates and is highly enriched in cruciferous vegetables. Our previous study showed that resveratrol, when used at high concentrations, inhibited cell proliferation, caused the cell cycle arrest and induced apoptotic cell death in glioma cells. In the current study, we tested the effect of combination treatment with resveratrol and sulforaphane, when both were used at low concentrations, on cell proliferation, migration and death in human U251 glioma cells. Our study shows that combination treatment with resveratrol and sulforaphane inhibits cell proliferation and migration, reduces cell viability, induces lactate dehydrogenase release, decreases pro-survival Akt phosphorylation and increases caspase-3 activation. The use of combination of bioactive food components, such as resveratrol and sulforaphane, may be a viable approach for the treatment of glioma.

Topics: Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Glioma; Humans; Isothiocyanates; Resveratrol; Stilbenes; Sulfoxides; Thiocyanates

Resveratrol, a stilbene found in grapes and wine, is one of the most interesting natural compound due to its role exerted in cancer prevention and therapy. In particular, resveratrol is able to delay cell cycle progression and to induce apoptotic death in several cell lines. Here we report that resveratrol treatment of human glioblastoma cells induces a delay in cell cycle progression during S phase associated with an increase in histone H2AX phosphorylation. Furthermore, with an in vitro assay of topoisomerase IIalpha catalytic activity we show that resveratrol is able to inhibit the ability of recombinant human TOPO IIalpha to decatenate kDNA, so that it could be considered a TOPO II poison.

Topics: Antigens, Neoplasm; Antineoplastic Agents, Phytogenic; Brain Neoplasms; Cell Cycle; Cell Line, Tumor; DNA Breaks, Double-Stranded; DNA Topoisomerases, Type II; DNA-Binding Proteins; Dose-Response Relationship, Drug; Glioma; Histones; Humans; Phosphorylation; Resveratrol; Stilbenes; Topoisomerase II Inhibitors

Neurofibromatosis type 1 (NF1) is the most common genetic disease affecting the nervous system. Patients typically develop many tumors over their lifetime, leading to increased morbidity and mortality. The NF1 gene, mutated in NF1, is also commonly mutated in sporadic glioblastoma multiforme (GBM). Because both NF1 and GBM are currently incurable, new therapeutic approaches are clearly needed. Natural products represent an opportunity to develop new therapies, as they have been evolutionarily selected to play targeted roles in organisms. Schweinfurthin A is a prenylated stilbene natural product that has previously shown specific inhibitory activity against brain and hematopoietic tumor lines. We show that patient-derived GBM and NF1 malignant peripheral nerve sheath tumor (MPNST) lines, as well as tumor lines derived from the Nf1-/+;Trp53-/+ (NPcis) mouse model of astrocytoma and MPNST are highly sensitive to inhibition by schweinfurthin A and its synthetic analogs. In contrast, primary mouse astrocytes are resistant to the growth inhibitory effects of schweinfurthin A, suggesting that schweinfurthin A may act specifically on tumor cells. Stable transfection of the GTPase-activating protein related domain of Nf1 into Nf1-/-;Trp53-/- astrocytoma cells confers resistance to schweinfurthin A. In addition, the profound effect of schweinfurthin A on dynamic reorganization of the actin cytoskeleton led us to discover that schweinfurthin A inhibits growth factor-stimulated Rho signaling. In summary, we have identified a class of small molecules that specifically inhibit growth of cells from both central and peripheral nervous system tumors and seem to act on NF1-deficient cells through cytoskeletal reorganization correlating to changes in Rho signaling.

Topics: Animals; Animals, Newborn; Brain Neoplasms; Cell Proliferation; Cells, Cultured; Drug Evaluation, Preclinical; Genes, Neurofibromatosis 1; Glioma; Humans; Mice; Mice, Transgenic; Models, Biological; Neurofibromatosis 1; Neurofibromin 1; Protein Structure, Tertiary; rho GTP-Binding Proteins; Signal Transduction; Stilbenes; Substrate Specificity

Glioblastoma multiforme (GBM) is the most malignant intracranial tumour that develops in both adults and children. Microarray gene analyses have confirmed that the human YKL-40 gene is one of the most over-expressed genes in these tumours but not in normal brain tissue. Clinical studies have shown that serum YKL-40 levels are positively correlated with tumour burden in addition to being an independent prognostic factor of a short relapse-free interval as well as short overall survival in patients with various cancers. Our previous study revealed that YKL-40 was closely correlated with the pathological grades of human primary astrocytomas and played a crucial role in glioma cell proliferation. Hence, YKL-40 could be an attractive target in the design of anti-cancer therapies.. Cell viability and invasion assays were performed to detect the cell proliferation and invasive ability of U87 cells induced by resveratrol (3, 5, 4'-trihydroxystilbene; Res) or YKL-40 small-interfering RNAs (siRNAs). In addition, the luciferase assay, real-time RT-PCR, western blotting, and ELISA were used to measure YKL-40 promoter activity, mRNA, and protein expression, respectively. The expressions of phosphor-ERK1/2 and ERK1/2 were determined by western blotting.. Res inhibited U87 cell proliferation and invasion in vitro and repressed YKL-40 in U87 cells by decreasing the activity of its promoter and reducing mRNA transcription and protein expression in vitro. YKL-40 siRNA treatment also impaired the invasiveness of U87 cells. When U87 cells were cultured with 20 μM PD98059 (an ERK1/2 inhibitor) alone, with 20 μM PD98059 and 100 μM Res, or with 100 μM Res alone for 48 h, YKL-40 protein expression decreased most significantly in the Res-treated group. PD98059 partially reversed the decrease of YKL-40 protein expression induced by Res. Furthermore, phosphor-ERK1/2 expression was reduced by Res treatment in a time-dependent manner.. We demonstrated for the first time that Res represses YKL-40 expression in vitro; in addition, the ERK1/2 pathway is involved in this repression. This finding could extend the prospective use of Res in glioma research and enlarge the armamentarium for treating gliomas.

Topics: Adipokines; Antineoplastic Agents, Phytogenic; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chitinase-3-Like Protein 1; Culture Media; Disease-Free Survival; Gene Expression Regulation, Neoplastic; Glioma; Glycoproteins; Humans; Lectins; Prognosis; Promoter Regions, Genetic; Recurrence; Resveratrol; Stilbenes

Resveratrol (Res) has been reported to elicit many cellular responses including cell cycle arrest, differentiation, and apoptosis. This makes it a novel and potential anticancer agent. Moreover, the lipophilicity of Res raises the possibility of its application as a potential model drug in nanoparticle based delivery systems. Resveratrol is incorporated into mPEG-PCL based nanoparticles with high encapsulation efficiency due to its lipophilicity. The significant finding of the current study is that Res-loaded nanoparticles at lower concentration could lead to significantly higher cell death compared to equivalent dose of free Res and this difference of cytotoxicity could not be abrogated by the antioxidant Vitamin E. Furthermore, free Res shows significant less cytotoxicity than the equivalent dose of Res-loaded nanoparticles with the preconditioning of Vitamin E. Meanwhile, reactive oxygen species (ROS) determination revealed the significantly lower intracellular ROS levels in Res-treated cells compared to nanoparticle-treated cells. Therefore, the differential cytotoxicity between Res and Res-loaded nanoparticles may be mediated by the discrepancy of intracellular ROS levels. The present results suggest that Res-loaded nanoparticles could be a potential useful chemotherapeutic formulation for malignant glioma therapy and the development of traditional Chinese medicine with nanoscale drug formation warrants more intensive research in order to evaluate its clinical feasibility.

Topics: Animals; Biodegradation, Environmental; Cell Death; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Carriers; Glioma; Intracellular Space; Microscopy, Fluorescence; Nanoparticles; Particle Size; Rats; Reactive Oxygen Species; Resveratrol; Stilbenes; Vitamin E

Glioma is the most frequent and malignant primary human brain tumor with dismal prognosis despite multimodal therapy. Resveratrol and quercetin, two structurally related and naturally occurring polyphenols, are proposed to have anticancer effects. We report here that resveratrol and quercetin decreased the cell number in four glioma cell lines but not in rat astrocytes. Low doses of resveratrol (10 microM) or quercetin (25 microM) separately had no effect on apoptosis induction, but had a strong effect on caspase 3/7 activation when administered together. Western blot analyses showed that resveratrol (10 microM) and quercetin (25 microM) caused a reduction in phosphorylation of Akt, but this reduction was not sufficient by itself to mediate the effects of these polyphenols. Most important, resveratrol and quercetin chronically administered presented a strong synergism in inducing senescence-like growth arrest. These results suggest that the combination of polyphenols can potentialize their antitumoral activity, thereby reducing the therapeutic concentration needed for glioma treatment.

Topics: Aging; Animals; Animals, Newborn; Anticarcinogenic Agents; Antioxidants; Apoptosis; Astrocytes; Caspases; Colony-Forming Units Assay; Drug Combinations; Drug Synergism; Glioma; Humans; Immunoblotting; Mice; Quercetin; Rats; Rats, Wistar; Resveratrol; Stilbenes; Tumor Cells, Cultured

Astroglial cells are key modulators of neuropathology events. Resveratrol, a redox-active compound present in grapes and wine, has a wide range of biological effects. The aim of this study was to investigate whether resveratrol is able to prevent hydrogen peroxide (H(2)O(2))-induced oxidative damage in C6 astroglial cells. We found that following a short oxidative insult (Model I-1 mM H(2)O(2)/30 min), resveratrol increased glutamate uptake (60%), glutamine synthetase (GS) (139%), glutathione (GSH) (120%), and S100B secretion (24%); and attenuated DCFH oxidation (34%) as compared to H(2)O(2) values. Under less intense (0.1 mM H(2)O(2)), but lasting (6 h) insult (Model II), resveratrol had an opposite effect, potentiating the H(2)O(2)-induced decrease in glutamate uptake (from 34 to 63%), in GS (from 22 to 50%), in GSH (from 22 to 54%), and also potentiating DCFH oxidation (from 24 to 38%). The transcription factor, NF-kappaB, was activated in both models. Cell morphology alterations were also observed in the presence of H(2)O(2) with process-bearing cells, accompanied by cell body retraction and actin reorganization. This effect was not prevented by resveratrol, but was prevented by lysophosphatidic acid (LPA), a specific upstream positive regulator of Rho A. In summary, these findings showed that resveratrol, a redox-active compound, was able to modulate important neurotrophic function of astroglial cells under different oxidative conditions.

Topics: Actins; Analysis of Variance; Animals; Antioxidants; Astrocytes; Dose-Response Relationship, Drug; Drug Interactions; Electrophoretic Mobility Shift Assay; Glioma; Glutamate-Ammonia Ligase; Glutamic Acid; Glutathione; Hydrogen Peroxide; Nerve Growth Factors; NF-kappa B; Oxidants; Phorbol Esters; Propidium; Rats; Reactive Oxygen Species; Resveratrol; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Stilbenes

Previous study reported that resveratrol has anti-tumor activity. In this study, we investigated the involvement of autophagy in the resveratrol-induced apoptotic death of human U251 glioma cells.. The growth inhibition of U251 cells induced by resveratrol was assessed with methyl thiazolyl tetrazolium (MTT). The activation of autophagy and proapoptotic effect were characterized by monodansylcadaverine labeling and Hoechst stain, respectively. Mitochondrialtransmembrane potential (DeltaPsim) was measured as a function of drug treatment using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1). The role of autophagy and apoptosis in the resveratrol-induced death of U251 cells was assessed using autophagic and caspase inhibitors. Immunofluorescence, flow cytometry, and Western blot analysis were used to study the apoptotic and autophagic mechanisms.. Methyl thiazolyl tetrazolium (MTT) assays indicated that resveratrol decreased the viability of U251 cells in a dose- and time-dependent manner. Flow cytometry analysis indicated that resveratrol increased cell population at sub-G1 phase, an index of apoptosis. Furthermore, resveratrol-induced cell death was associated with a collapse of the mitochondrial membrane potential. The pan-caspase inhibitor Z-VAD-fmk suppressed resveratrol-induced U251 cell death. Resveratrol stimulated autophagy was evidenced by punctuate monodansylcadaverine(MDC) staining and microtubule-associated protein light chain 3 (LC3) immunoreactivty. Resveratrol also increased protein levels of beclin 1 and membrane form LC3 (LC3-II). Autophagy inhibitors 3-methylademine (3-MA) and bafilomycin A1 sensitized the cytotoxicity of resveratrol.. Together, these findings indicate that resveratrol induces autophagy in human U251 glioma cells and autophagy suppressed resveratrol-induced apoptosis. This study thus suggests that autophagy inhibitors can increase the cytotoxicity of resveratrol to glioma cells.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Coloring Agents; Glioma; Humans; Membrane Potentials; Microscopy, Fluorescence; Mitochondrial Membranes; Resveratrol; Stilbenes; Tetrazolium Salts; Thiazoles

To investigate the suppressive effect of resveratrol on growth of U251 human glioma cells and its correlated mechanism.. U251 human glioma cells were treated with resveratrol at various concentrations, MTT assay was used to determine the inhibitory rate of cell proliferation, FCM to detect the cell apoptosis, the expressions of Bcl-2, Bcl-XL, STAT3 and CyclinD1 were analysed by immunohistochemistry and Western blot to examine the expression of Bcl-2, Bcl-XL, STAT3, CyclinD1, Caspase-3 and Bax.. After treatment with resveratrol, MTT assay showed the growth of U251 cells was inhibited in dose-dependent and time-dependent manners, apoptosis of cells advanced stage was built up, immunohistochemical staining displayed decreased the expression of Bcl-2, Bcl-XL, STAT3 and CyclinD1 and Western blot showed that resveratrol decreased the expression of Bcl-2, Bcl-XL, STAT3 and CyclinD1, and built up Bax and Caspase-3.. It is possible that downregulated the expression of Bcl-2, Bcl-XL, but upregulated Bax and Caspase-3, and the indication was obviously in dose-dependent and time-dependent manners.

Topics: Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Blotting, Western; Caspase 3; Cell Line, Tumor; Cyclin D1; Gene Expression Regulation, Neoplastic; Glioma; Humans; Immunohistochemistry; Proto-Oncogene Proteins c-bcl-2; Resveratrol; STAT3 Transcription Factor; Stilbenes

Resveratrol (trans-3,4', 5-trihydroxystilbene) is a naturally occurring polyphenolic compound that has antiinflammatory, antioxidant, neuroprotective properties and acts as a chemopreventive agent. Resveratrol causes cell cycle arrest and induces apoptotic cell death in various types of cancer cells. In the current studies, the effect of resveratrol on phosphoinositide kinase-3 (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway was examined in human U251 glioma cells. Resveratrol decreased both the expression and phosphorylation of Akt. Inhibitors of PI3K (LY294002) and Akt (SH-6) enhanced resveratrol-induced LDH release and caspase-3 activation. Resveratrol reduced phosphorylation of ribosomal protein S6 and the mTOR inhibitor rapamycin further enhanced resveratrol-induced cell death. These results suggest that the downregulation of PI3K/Akt/mTOR signaling pathways may be an important mediator in resveratrol-induced apoptosis in glioma cells.

Topics: Antineoplastic Agents, Phytogenic; Caspase 3; Cell Line, Tumor; Cyclin D1; Dose-Response Relationship, Drug; Down-Regulation; Glioma; Humans; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Proto-Oncogene Proteins c-akt; Resveratrol; Signal Transduction; Stilbenes; TOR Serine-Threonine Kinases

The stilbene resveratrol (RV) initiates p53-dependent apoptosis via plasma membrane integrin alphaVbeta3 in human cancer cells. A thyroid hormone (L-thyroxine, T(4)) membrane receptor also exists on alphaVbeta3. Stilbene and T(4) signals are both transduced by extracellular-regulated kinases 1 and 2 (ERK1/2); however, T(4) promotes cell proliferation in cancer cells, whereas RV is pro-apoptotic. Thyroid hormone has been shown to interfere with RV-induced apoptosis. However, the mechanisms involved are not fully understood. In this study, we examined the mechanism whereby T(4) inhibits RV-induced apoptosis in glioma cells. RV activated conventional protein kinase C and ERK1/2 and caused nuclear localization of cyclooxygenase-2 (COX-2), consequent p53 phosphorylation and apoptosis. RV-induced ERK1/2 activation is involved in not only COX-2 expression but also nuclear COX-2 accumulation. NS-398, a COX-2 inhibitor, did not affect ERK1/2 activation, but reduced the nuclear abundance of COX-2 protein and the formation of complexes of nuclear COX-2 and activated ERK1/2 that are required for p53-dependent apoptosis in RV-treated cells. T(4) inhibited RV-induced nuclear COX-2 and cytosolic pro-apoptotic protein, BcLx-s, accumulation. Furthermore, T(4) inhibited RV-induced apoptosis by interfering with the interaction of nuclear COX-2 and ERK1/2. This effect of T(4) was prevented by tetraiodothyroacetic acid (tetrac), an inhibitor of the binding of thyroid hormone to its integrin receptor. Tetrac did not, in the absence of T(4), affect induction of apoptosis by RV. Thus, the receptor sites on alphaVbeta3 for RV and thyroid hormone are discrete and activate ERK1/2-dependent downstream effects on apoptosis that are distinctive.

Topics: Apoptosis; Brain Neoplasms; Cyclooxygenase 2; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Glioma; Humans; Integrin alphaVbeta3; Phosphorylation; Protein Kinase C; Resveratrol; Stilbenes; Thyroxine

Resveratrol (Res) has been reported to inhibit tumor initiation, promotion, and progression in a variety of cell culture systems depending on the specific cell type and cellular environment. In the present study, we determined the effect of Res on the cell growth and apoptosis of rat glioma C6 cell line as well as mouse fibroblast 3T3 cell line, in vitro. Concurrently, we investigated whether caspase-3 is involved in the Res-induced apoptosis of rat glioma cells. Exposure to Res exhibits a significant anti-proliferative effect and induces an increase in the population of apoptotic cells on C6 cells in a concentration- and time-dependent manner, but not for normal 3T3 fibroblast cells, as measured by methyl thiazolyl tetrazolium assay and flow cytometer. Distinguished increase of C6 cells in S phase is observed after the treatment of Res as compared to insignificant change in cell cycle distribution of 3T3 cells. TdT-mediated dUTP nick end labeling fluorescence staining, HE staining, and scanning electron microscope revealed abnormal morphology and ultrastructure in C6 cells treated with Res. Our data showed that Res can increase the expression and induced the activation of caspase-3 in rat glioma C6 cells. These results suggest that Res has significant apoptosis-inducing effect on C6 glioma cells other than normal fibroblast 3T3 cells in vitro and caspase-3 may act as a potential mediator in the process.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Blotting, Western; Brain Neoplasms; Caspase 3; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Fibroblasts; Flow Cytometry; Glioma; In Situ Nick-End Labeling; Mice; Rats; Resveratrol; Stilbenes

The antioxidant compound, trans-resveratrol, is found in substantial amounts in several types of red wine and has been proposed to have beneficial effects in brain pathologies that may involve oxidative stress. The objective of the present study was to investigate the genoprotective effects of resveratrol under conditions of oxidative stress induced by hydrogen peroxide in C6 glioma cells. DNA damage was assessed by the alkaline single-cell gel electrophoresis assay or comet assay. In order to investigate the genoprotective effects of resveratrol against oxidative stress induced by hydrogen peroxide on DNA damage, two models of oxidative stress induction were utilized. (I) 1mM hydrogen peroxide for 0.5h (10-250 microM of resveratrol) and (II) 0.1 or 0.5mM hydrogen peroxide for 6h (10-100 microM of resveratrol). Resveratrol was able to prevent oxidative damage to cellular DNA, induced in model I, at all concentrations tested; however, at 6h of incubation, resveratrol prevented DNA damage only partially. After 6h of incubation (up to 48h) resveratrol per se induced a slight time and dose-dependent DNA damage. In conclusion, these results provide evidence that resveratrol may act as a significantly bioactive compound, supporting the possibility that, due to its antioxidant properties, it may be important in health and disease for protecting against DNA damage through oxidative stress.

Topics: Analysis of Variance; Animals; Antioxidants; Cell Line, Tumor; Comet Assay; DNA Damage; Dose-Response Relationship, Drug; Drug Interactions; Glioma; Hydrogen Peroxide; Mice; Oxidative Stress; Propidium; Resveratrol; Stilbenes

Resveratrol has been reported to exert a variety of important pharmacological effects including anti-inflammatory, cardioprotective and cancer chemopreventive properties; however, its mechanisms of action are not completely under-stood. beta-amyloid protein is considered to be responsible for the formation of senile plaques that accumulate in the brains of patients with Alzheimer disease. In the present study, we investigated the protective effect of resveratrol on beta-amyloid-induced cytoxicity in cultured rat astroglioma C6 cells. Preincubation of C6 cells with resveratrol concentration-dependently protected the cells from the growth inhibition induced by beta-amyloid treatment. beta-amyloid treatment led to increased nitric oxide (NO) synthesis and inducible nitric oxide synthase (iNOS) expression; however, cells pretreated with resveratrol showed a dose-dependent inhibition of NO production and iNOS expression following beta-amyloid treatment. Resveratrol also attenuated beta-amyloid-induced prostaglandin E2 (PGE2) release, which was associated with the inhibition of cyclooxygenase (COX)-2 expression. Furthermore, beta-amyloid treatment induced nuclear translocation of NF-kappaB, which was suppressed by resveratrol pretreatment. Collectively, the present results indicate that modulation of nuclear factor-kappaB (NF-kappaB) activity is involved in the neuroprotective action of resveratrol against beta-amyloid-induced toxicity.

Topics: Amyloid beta-Peptides; Animals; Antioxidants; Cell Line, Tumor; Cyclooxygenase 2; Dinoprostone; Down-Regulation; Glioma; Neuroglia; Neuroprotective Agents; NF-kappa B; Nitric Oxide Synthase Type II; Protein Transport; Rats; Resveratrol; Stilbenes; Transcriptional Activation

Resveratrol (trans-3,5,4',-trihydroxystilbene) is assumed to possess cancer-preventive and cancer-therapeutic properties. The aim of this project was to analyze cellular effects of resveratrol in metabolically active H4IIE rat hepatoma cells in comparison to metabolically poorly active C6 rat glioma cells. Resveratrol is rapidly taken up by both cell types and acts as a potent intracellular antioxidant. On the other hand, resveratrol in higher concentrations is relatively toxic to both cell lines as measured by the neutral red accumulation assay. In H4IIE cells, resveratrol concentrations rapidly decline to very low levels during the first hours of incubation due to formation of resveratrol glucuronides. The first resveratrol effect found at 3h after the start of resveratrol treatment was the induction of mild DNA damage as detected by the comet assay. Cell death was caused via induction of apoptosis as detected by caspase activation, oligonucleosomal DNA fragmentation and formation of apoptotic nuclei. Following DNA damage, resveratrol led to an activation of caspases 2 and 8/10 at 6h and consequently of caspase 3 at 12h, but failed to activate caspase 9. In contrast to H4IIE cells, resveratrol is not metabolised in C6 glioma cells and accumulates to concentrations which are assumed to drive the cell into necrosis. This suggests that the mode of cell death caused by resveratrol and the usefulness of resveratrol for cancer prevention and treatment critically depends on the metabolic capacity of the tumor cell to be eradicated.

Topics: Animals; Antineoplastic Agents; Antioxidants; Apoptosis; Carcinoma, Hepatocellular; Caspases; Cell Line; Cell Survival; Comet Assay; DNA Damage; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Glioma; Necrosis; Rats; Resveratrol; Stilbenes

Resveratrol, a phytoalexin found mainly in grapes, is a promising natural product with anti-cancer and cardio-protective activities. Here, we investigated, in C6 glioma cells, the effect of resveratrol on some specific parameters of astrocyte activity (glutamate uptake, glutamine synthetase and secretion of S100B, a neurotrophic cytokine) commonly associated with the protective role of these cells. Cell proliferation was significantly decreased by 8% and 26%, following 24h of treatment with 100 and 250 microM resveratrol. Extracellular S100B increased after 48 h of resveratrol exposure. Short-term resveratrol exposure (from 1 to 100 microM) induced a linear increase in glutamate uptake (up to 50% at 100 microM resveratrol) and in glutamine synthetase activity. Changes in these glial activities can contribute to the protective role of astrocytes in brain injury conditions, reinforcing the putative use of this compound in the therapeutic arsenal against neurodegenerative diseases and ischemic disorders.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Enzyme Activation; Glioma; Glutamate-Ammonia Ligase; Glutamic Acid; Rats; Resveratrol; Stilbenes

Resveratrol (trans-3,4',5-trihydroxystilbene) is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Resveratrol has antiinflammatory and antioxidant properties, and also has potent anticancer properties. Human glioma U251 cells were used to understand the molecular mechanisms by which resveratrol acts as an anticancer agent, since glioma is a particularly difficult cancer to treat and eradicate. Our data show that resveratrol induces dose- and time-dependent death of U251 cells, as measured by lactate dehydrogenase release and internucleosomal DNA fragmentation assays. Resveratrol induces activation of caspase-3 and increases the cleavage of the downstream caspase substrate, poly(ADP-ribose) polymerase. Resveratrol-induced DNA fragmentation can be completely blocked by either a general caspase inhibitor (Z-VAD-FMK) or a selective caspase-3 inhibitor (Z-DEVD-FMK), but not by a selective caspase-1 inhibitor. Resveratrol induces cytochrome c release from mitochondria to the cytoplasm and activation of caspase-9. Resveratrol also increases expression of proapoptotic Bax and its translocation to the mitochondria. Resveratrol inhibits U251 proliferation, as measured by MTS assay [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt], and induces G0/G1 growth arrest, as determined by flow cytometry. The cyclin-dependent kinase inhibitor, olomoucine, prevents cell cycle progression and resveratrol-induced apoptosis. These results suggest that multiple signaling pathways may underlie the apoptotic death of U251 glioma induced by resveratrol, which warrants further exploration as an anticancer agent in human glioma.

Topics: Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Caspase 9; Caspase Inhibitors; Caspases; Cell Cycle; Cell Line, Tumor; Cytochromes c; Cytoplasm; DNA Fragmentation; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Flavonoids; Glioma; Humans; Kinetin; L-Lactate Dehydrogenase; Phenols; Poly(ADP-ribose) Polymerases; Polyphenols; Proto-Oncogene Proteins c-bcl-2; Purines; Resveratrol; Signal Transduction; Stilbenes; Subcellular Fractions; Time Factors; Up-Regulation

As one of the in vitro model experiments for investigating a possible effect of extracellular environmental stresses on glial cell proliferation, the influence of high salt culture conditions on the growth of rat C6 glioma cells was examined. Exposure to the culture medium containing high concentrations of NaCl reduced the number of viable cells in a concentration-dependent manner without any significant change in their viability. In contrast, proliferation of these cells was not substantially altered by culturing them in hyperosmotic medium containing either sucrose or glycerol, both of which were osmotically almost equivalent to high salt culture medium. On the other hand, expression of the egr-1 gene, an immediate early gene related to the proliferation and differentiation of various cells, was enhanced by culturing glioma cells in high salt medium while the reduction of glial fibrillary acidic protein content, an index of glial cell differentiation, was observed under the same culture conditions. Further studies on the relationship between egr-1 gene expression and the cell cycle showed that cell-cycle progression was arrested at S-phase by culturing glioma cells in high salt medium. Moreover, both resveratrol and CPT-11, which are known to arrest cell-cycle progression, elevated egr-1 mRNA levels in glioma cells. Thus, these observations suggest that high salt culture conditions might suppress the proliferation of rat C6 glioma cells as a consequence of arresting cell-cycle progression at S-phase, resulting secondarily in the compensatory enhancement of egr-1 gene expression.

Topics: Animals; Camptothecin; Cell Line, Tumor; Cell Proliferation; Cell Survival; Culture Media; Early Growth Response Protein 1; Enzyme Inhibitors; Glial Fibrillary Acidic Protein; Glioma; Hypertonic Solutions; Irinotecan; Osmolar Concentration; Rats; Resveratrol; S Phase; Sodium Chloride; Stilbenes

We wanted to investigate the antitumor effects and effect on angiogenesis of resveratrol in rat RT-2 gliomas.. RT-2 glioma cells were treated with resveratrol, and then cytotoxicity was assayed, apoptosis was measured by flow-activated cell sorter flow cytometry, and expression of vascular endothelial growth factor was measured by reverse transcription-PCR. Tumor size, animal survival time, and survival rate were followed in resveratrol-treated rats with s.c. or intracerebral gliomas. Furthermore, in vitro proliferation was assayed to explore the effect of resveratrol on the proliferation of ECV304 human umbilical vein endothelial cells. Expression of CD31 in resveratrol-treated gliomas was followed immunohistochemically to study the effect of resveratrol on the glioma-induced angiogenesis.. Resveratrol was demonstrated to exert cytotoxic effects and induce glioma cell apoptosis in a concentration- and time-dependent manner (P < 0.05). Resveratrol (40 mg/kg/day) exerted significant antitumor effects on s.c. tumors, including slower tumor growth rate, longer animal survival time, and higher animal survival rate (P < 0.05). In contrast, resveratrol affected intracerebral tumors at only an increased dose (100 mg/kg/day), prolonging animal survival (P < 0.05) without affecting survival rate. The expression of vascular endothelial growth factor in the glioma cells and the proliferation of ECV304 cells were inhibited by resveratrol in a concentration-dependent manner. Immunohistochemical analyses showed that the s.c. gliomas from resveratrol-treated rats had fewer microvessel densities than did control rats (P < 0.01).. Resveratrol caused significant glioma cell cytotoxicity and apoptosis, exerted antitumor effects on the s.c. and intracerebral gliomas, and inhibited angiogenesis in s.c. gliomas. Thus, resveratrol might be considered a possible treatment strategy for gliomas.

Topics: Angiogenesis Inhibitors; Animals; Apoptosis; Cell Division; Cell Line; Cell Line, Tumor; Disease Models, Animal; Endothelium, Vascular; Flow Cytometry; Glioma; Kinetics; Neovascularization, Pathologic; Rats; Resveratrol; Stilbenes; Umbilical Veins

The influence of combretastatin A-4 disodium phosphate (CA-4, 50mg/kg intraperitoneally (i.p.)) and vinblastine (2mg/kg i.p.) on interstitial fluid pressure (IFP) was assessed in BT4An rat gliomas implanted subcutaneously in the neck. Furthermore the growth inhibitory effect of vinblastine and the distribution of fluorescence-conjugated vinblastine (BODIPY-vinblastine) were investigated. Tumors at different volumes were compared. Whereas CA-4 had no major influence on IFP, independent of tumor size, vinblastine increased the IFP in neoplasms above 8 cm(3) (P=0.03). Vinblastine yielded a significant tumor response only in tumors below 2.1 cm(3) (P=0.03). The distribution of BODIPY-vinblastine was heterogeneous and comparable despite tumor volume differences. We conclude that the influence of vinblastine on IFP is more pronounced than that of CA-4 in BT4An neck tumors, and that vinblastine may reduce subsequent drug delivery to solid tumors by increasing the IFP.

Topics: Animals; Antineoplastic Agents, Phytogenic; Drug Delivery Systems; Extracellular Space; Female; Glioma; Male; Neoplasm Transplantation; Pressure; Rats; Stilbenes; Vinblastine

Attacking tumor vasculature is a promising approach for the treatment of solid tumors. The tubulin inhibitor combretastatin A-4 disodium phosphate (CA-4) is a new vascular targeting drug which displays a low toxicity profile. We wanted to investigate how CA-4 influences tumor perfusion in the BT4An rat glioma and how the vascular targeting properties of CA-4 could be exploited to augment hyperthermic damage towards tumor vasculature.. We used the (86)RbCl extraction technique to assess how CA-4 influences tumor perfusion, and the tumor endothelium was examined for morphological changes induced by the drug. We combined CA-4 (50 mg/kg i.p.) with hyperthermia (44 degrees C, 60 min) at different time intervals to evaluate how therapy should be designed to affect tumor growth, and we studied the tumors histologically to assess tissue viability.. We found that CA-4 induced a profound, but transient reduction in tumor perfusion 3-6 h postinjection. If hyperthermia was administered 3-6 h after injecting CA-4, massive hemorrhagic necrosis developed, and tumor response was significantly enhanced compared to simultaneous administration of the two treatment modalities (P<0.005). CA-4 alone had no influence on tumor growth and failed to disrupt the vasculature of the BT4An solid tumors. Interestingly though, a mild endothelial edema was observed in some tumor areas 3 h after injecting CA-4.. We conclude that the combination of CA-4 and hyperthermia is a potent therapeutic option for BT4An tumors, but the selection of adequate time intervals between CA-4 and hyperthermia are imperative to obtain tumor response.

Topics: Animals; Antineoplastic Agents, Phytogenic; Combined Modality Therapy; Female; Glioma; Hyperthermia, Induced; Male; Neoplasm Transplantation; Rats; Rats, Inbred Strains; Stilbenes

Combretastatin A-4 disodium phosphate (CA-4) enhances thermal damage in s.c. BT(4)An rat gliomas. We currently investigated how CA-4 and hyperthermia affect the tumor microenvironment and neovasculature to disclose how the two treatment modalities interact to produce tumor response.. By confocal microscopy and immunostaining for von Willebrand factor, we examined the extent of vascular damage subsequent to CA-4 (50 mg/kg) and hyperthermia (waterbath 44 degrees C, 60 min). The influence on tumor oxygenation was assessed using interstitial pO(2)-probes (Licox system) and by immunostaining for pimonidazole. We examined the direct effect of CA-4 on the tumor cell population by flow cytometry (cell cycle distribution) and immunostaining for beta-tubulin (cytoskeletal damage).. Whereas slight vascular damage was produced by CA-4 in the BT(4)An tumors, local hyperthermia exhibited moderate anti-vascular activity. In tumors exposed to CA-4 3 h before hyperthermia, massive vascular damage ensued. CA-4 reduced the pO(2) from 36.1 to 17.6 mmHg (P=0.01) in the tumor base, and tumor hypoxia increased slightly in the tumor center (pimonidazole staining). Extensive tumor hypoxia developed subsequent to hyperthermia or combination therapy. Despite a profound influence on beta-tubulin organization in vitro, CA-4 had no significant effect on the cell cycle distribution in vivo.. Our results indicate that the anti-vascular activity exhibited by local hyperthermia can be augmented by previous exposure to CA-4.

Topics: Animals; Antineoplastic Agents, Phytogenic; Combined Modality Therapy; Female; Glioma; Hyperthermia, Induced; Male; Rats; Rats, Inbred Strains; Stilbenes

To investigate the toxicity of combretastatin A-4 disodium phosphate (CA-4) and its vascular effects in the subcutaneous (s.c.) BT4An rat glioma, and additionally, to determine the tumor response of CA-4 combined with hyperthermia.. For assessment of drug toxicity, rats were given 50, 75, or 100 mg/kg CA-4 and followed by daily registration of weight and side effects. Interstitial tumor blood flow was determined by laser Doppler flowmetry in rats injected with 50 mg/kg CA-4. In the tumor response study we administered CA-4 50 mg/kg alone or combined with hyperthermia (waterbath 44 degrees C for 60 min) 0 or 3 h later.. We found that CA-4, at a well-tolerated dose of 50 mg/kg, induced a considerable time-dependent decrease in the tumor blood flow. Tumor blood flow was reduced by 47-55% during the first 110 min after injecting CA-4, and thereafter remained decreased until the measurements were terminated. Administering CA-4 3 h before hyperthermia yielded the best tumor response and increased tumor growth time significantly compared with simultaneous administration of CA-4 and hyperthermia (p = 0.03). Interestingly, CA-4 alone did not influence tumor growth.. CA-4 induces a gradual reduction in tumor blood flow which can be exploited to sensitize the BT4An tumor for hyperthermia.

Topics: Animals; Antineoplastic Agents, Phytogenic; Combined Modality Therapy; Diarrhea; Female; Glioma; Hyperthermia, Induced; Laser-Doppler Flowmetry; Male; Radiobiology; Rats; Rats, Inbred Strains; Stilbenes; Time Factors

SITS, an inhibitor of anion exchange, was found to be a potent and selective inhibitor of L-glutamic acid uptake by cultured LRM55 glioma cells and rat brain astrocytes. Synaptosomal uptake of glutamate was relatively insensitive to inhibition by SITS. This differential effect indicates that the glutamate transport system in glia differs from that in neurons and that SITS may provide a tool for investigating the exclusive neuronal transport and metabolism of L-glutamic acid.

Topics: 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; Animals; Astrocytes; Brain; Cell Line; Glioma; Kinetics; Neoplasms, Experimental; Neuroglia; Neurons; Rats; Rats, Inbred Strains; Spinal Cord Neoplasms; Stilbenes; Synaptosomes