Injection Of C6 Glioma Cells Research Articles

Antioxidant Effect of Propofol in Gliomas and Its Association With Divalent Metal Transporter 1.

BackgroundOxidative stress enhances tumor invasion and metastasis in brain cancer. The activation of divalent metal transporter 1 (DMT1), which is regulated by glutamate receptors, can result in the increase of oxidative stress and risk of cancer development. Propofol, an anesthetic with antioxidant capacity, has been shown to decrease oxidative stress in several different types of cancer. However, the underlying mechanism remains unclear. Therefore, the present study aimed to elucidate the mechanism underlying the suppression of oxidative stress in glioma cells by propofol. It was hypothesized that propofol may inhibit oxidative stress in gliomas via suppressing Ca2+-permeable α-amino-3-hydroxyl-5-methylisoxazole-4-propionic acid (AMPA) receptor (CPAR)-DMT1 signaling.MethodsMale Wistar rats with C6 gliomas, which were established by intracranial injection of C6 glioma cells, were either treated with propofol or not for 6 h before being sacrificed. The levels of AMPA receptor subunit GluR2 and DMT1 protein expression were assessed using western blotting. The association between CPARs and DMT1 was confirmed in vitro using the AMPA receptor activator (R, S)-AMPA. Glutathione and reactive oxygen species assay kits were used to evaluate tumor oxidative stress. The effect of propofol on glioma proliferation was evaluated by determining tumor weight, cell cycles and a growth curve.ResultsPropofol infusion at either 20 or 40 mg/kg-1/h-1 increased GluR2 levels and downregulated DMT1 expression as well as glutathione content markedly in the periphery compared with that in the glioma core. The in vitro results revealed that (R, S)-AMPA increased DMT1 expression and reactive oxygen species levels, which were partly reversed by propofol treatment.ConclusionPropofol regulated DMT1 expression by modulating CPARs, resulting in the inhibition of tumor oxidative stress and glioma growth. The present study provides evidence for optimizing the selection of anesthetic drugs in perioperative management and prognosis of patients with glioma.

The effect of elemene in combination with vascular endothelial growth factor polyclonal antibody on the expression of proliferating cell nuclear antigen and tissue inhibitor of metalloproteinase-1 in brain glioma tissue of rats

Objective To investigate the effect of elemene in combination with vascular endothelial growth factor (VEGF) polyclonal antibody on the expression of proliferating cell nuclear antigen (PCNA) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in brain glioma tissue of rats. Methods The rat glioma models were built by intracerebral injection of C6 glioma cells. Forty-eight successful rat models were selected and randomly divided into model group, elemene group, VEGF polyclonal antibody group and elemene in combination with VEGF polyclonal antibody group, with 12 rats in each group. Rats in model group were performed intraperitoneal injection of 0.5 ml normal saline, rats in elemene group were performed intraperitoneal injection of 0.5 ml elemene injection, rats in VEGF polyclonal antibody group were performed intraperitoneal injection of 0.5 ml VEGF polyclonal antibody, and rats in elemene in combination with VEGF polyclonal antibody group were performed intraperitoneal injection of 0.5 ml elemene injection and 0.5 ml VEGF polyclonal antibody. The drug was administered on alternate days for 7 consecutive times. The tumour volume, tumor inhibition rate and the expression of PCNA and TIMP-1 in brain tissue of the rats between the groups were compared. Statistics with SPSS 21.0 software, measurement data for Mean±SD indicated that one factor variance analysis was used for the comparison between the two groups, and t test was used for the comparison between the two groups. Results (1) Tumor volume and tumor inhibition rate: The tumor volumes in model group, elemene group, polyclonal group, VEGF polyclonal antibody group and elemene in combination with VEGF polyclonal antibody group were (68.54±8.12), (37.65±6.24), (39.12±6.41), (30.12±5.24) mm3, respectively; the tumor inhibition rates in elemene group, VEGF polyclonal antibody group and elemene in combination with VEGF polyclonal antibody group were (445.07±6.45)%, (42.92±6.52)%, (56.05±7.21)%, respectively. The tumor volume in elemene in combination with VEGF polyclonal antibody group was significantly smaller than that in control group (t=10.449, 9.851, 13.772, P<0.01); the tumor volume in elemene in combination with VEGF polyclonal antibody group was significantly smaller than that in elemene group and VEGF polyclonal antibody group (t=3.201, 3.766, P<0.05), and the tumor inhibition rate was significantly higher than that in elemene group and VEGF polyclonal antibody group (t=3.932, 4.679, P<0.05). (2) As to the expression of PCNA and TIMP-1 in brain tissue: the PCNA indexes of tumors in model group, elemene group, VEGF polyclonal antibody group and elemene in combination with VEGF polyclonal antibody group were (73.12±10.21, 44.24±6.42, 47.36±7.12, 37.45±5.24), respectively, and the TIMP-1 indexes were (45.24±6.45, 62.45±8.15, 59.45±7.32, 78.65±11.24), respectively. The PCNA indexes of tumors in elemene group, VEGF polyclonal antibody group and elemene in combination with VEGF polyclonal antibody group were significantly lower than that in model group (t=8.295, 7.447, 10.767, P<0.05, P<0.01), the TIMP-1 indexes were significantly higher than that in model group (t=5.736, 5.401, 8.931, P<0.05, P<0.01); the PCNA index of tumor in elemene in combination with VEGF polyclonal antibody group was significantly lower than that in elemene group and VEGF polyclonal antibody group (t=2.838, 3.491, P<0.05), and the TIMP-1 index was significantly higher than that in elemene group and VEGF polyclonal antibody group (t=4.042, 4.700, P<0.05). Conclusion Elemene in combination with VEGF polyclonal antibody can help to inhibit the growth of brain glioma tissue, which may be related to the regulation of PCNA and the expression of TIMP-1 in brain tissue. Key words: Brain glioma; Elemene; Vascular endothelial growth factor polyclonal antibody; Proliferating cell nuclear antigen; Tissue inhibitor of metalloproteinase-1

Effect of Naringenin on metabolic markers, lipid profile and expression of GFAP in C6 glioma cells implanted rat's brain.

Naringenin, a flavanone, has been reported to exhibit a wide range of pharmacological properties including antitumor activity. We wanted to test the efficacy of Naringenin on C6 glioma cells-implanted into rats was investigated. Biochemical and immunohistochemical methods were used for analyzing various markers. Injection of C6 glioma cells into rat brain resulted in increased metabolic markers {Lactatate Dehydrogenase (LDH), 5' Nucleotidase 5'ND), creatine kinase (CK), Hexokinase (HK) and Glucose 6-phosphate dehydrogenase (G6PD)} and lipid profile (triglycerides, free fatty acids, phos-pholipids, total cholesterol and free cholesterol). Oral administration of Naringenin (50 mg /kg of BW for 30 days) significantly altered this biochemical profile. Further, the immuno fluorescence expression of Glial fibrilary acidic protein (GFAP) was also studied. In C6 glioma cells-implanted rats, increased expression of GFAP was noted on treatment with Naringenin. These observations suggest that Naringenin may participate by inhibiting glial cell tumorigenesis.

Expression of macrophage inflammatory protein‐1α and monocyte chemoattractant protein‐1 in glioma‐infiltrating microglia: Involvement of ATP and P2X7 receptor

Chemokines can be produced by gliomas, which mediate the infiltration of microglia, a characteristic feature of glioma-associated neuropathogenesis. ATP that is released at a high level from glioma has been reported to play a regulatory role in chemokine production in cultured glioma cells. The objective of this study was to define the potential role of extracellular ATP in the regulation of macrophage inflammatory protein-1α (MIP-1α) and monocyte chemoattractant protein-1(MCP-1) expression in glioma-associated microglia/macrophages. The results showed that Iba1(+) and ED1(+) microglia existed in the tumor at 3 and 7 day after injection of C6 glioma cells into the rat cerebral cortex (dpi). ED1(+) microglia/macrophages or Iba1(+) microglia in the glioma were also colocalized to MIP-1α- and MCP-1-expressing cells. In vitro study indicated that treatment with ATP and BzATP (an agonist for ATP ionotropic receptor P2X₇R) caused an increase in the intracellular levels of microglial MIP-1α and MCP-1. By using an extracellular Ca(2+) chelator (EGTA) and P2X₇R antagonists, oxidized ATP (oxATP) and brilliant blue G (BBG), we demonstrated that BzATP-induced production of MIP-1α and MCP-1 levels was due to P2X₇R activation and Ca(2+) -dependent regulation. Coadministration of C6 glioma cells and oxATP into the rat cerebral cortex resulted in a reduction of MIP-1α- and MCP-1-expressing microglia/macrophages. We suggest, based on the results from in vivo and in vitro studies, that a massive amount of ATP molecules released in the glioma tumor site may act as the regulator with P2X₇R signaling that increases MIP-1α and MCP-1 expression in tumor-infiltrating microglia/macrophages.

A rat glioblastoma model with diffuse leptomeningeal gliomatosis induced by intracarotid injection of C6 glioma cells

Objective: A reproducible brain tumor model using experimental animals is required to study biological behavior and develop more potent antineoplastic drugs and effective therapeutic modalities. In this work, we attempted to establish diffuse leptomeningeal gliomatosis in the rat by intracarotid injection of C6 glioma cells.Methods: Intracarotid injection of 1 × 107 C6 glioma cells in Wistar rats was performed to establish a primary diffuse leptomeningeal gliomatosis model. Ki-67 and matrix metalloproteinases (MMPs) immunohistochemistry staining were used to study the biological behavior of the developed tumor. Methodology, physical findings and histopathological features were also discussed.Results: Leptomeningeal gliomas grew in all Wistar rats after the administration of 1 × 107 C6 glioma cells. Intracranial hypertension, weight loss and cachexia developed, and the median survival time was 18.0 ± 2.9 days. The glioma mass distributed throughout the ventricles, the leptomeningeal regions in the brain and the brainstem, with typical pathological features of glioblastoma. The immunohistochemistry stainings showed high Ki-67 labeling index (42.1 ± 10.3%), and concomitant overexpression of MMP-2 and MMP-9 suggested proliferation, invasion and angiogenesis potential.Discussion: The advantage of the intracarotid injection route is the absence of an operative scar in the cranium. This established animal model is a novel model of primary diffuse leptomeningeal gliomatosis. This model probably can be used for pre-clinical testing in the progression of glioblastoma.

Transplantation of prodrug-converting neural progenitor cells for brain tumor therapy.

Since neural progenitor cells can engraft stably into brain tumors and differentiate along the neuronal and glial line, we tested the hypothesis that transplanted cytosine deaminase (CD)-expressing ST14A cells (an immortalized neural progenitor cell line) can convert locally 5-fluorocytosine (5-FC) into 5-fluorouracil (5-FU) and produce a regression of glioma tumors. ST14A, retrovirally transduced with the E. coli CD gene, showed a strong bystander effect on glioma cells as assessed by in vitro assay. Intracerebral injection of C6 glioma cells generated a rapidly growing tumoral mass. DiI prelabeled ST14A, coinjected into the rat brain with C6 glioma cells, survived in the tumoral mass up to 10 days and their number was not affected by in vivo 5-FC treatment. In contrast, a significant decrease of the glioma tumoral mass (-50%) was observed in 5-FC-treated rats. 5-FC had no effect on the tumor in the absence of CD-expressing ST14A cells. Our results support the feasibility of systems based on intratumoral transplantation of prodrug-converting cells for brain tumor therapy.

Blocking Neuron Migration and Cancer-It's All the RAGE

Amphoterin, a protein found in the extracellular matrix, is required for proper cortical neuron growth in brain development. Amphoterin is a ligand for RAGE, a transmembrane protein found at the growing edge of neurites. Because activated RAGE is important for neurite migration, it is possible that RAGE signaling is also important for aberrant invasion and metastasis in brain cancer. Taguchi et al. find that blocking RAGE activation leads to the suppression of tumor growth and metastases in mice. Injection of C6 glioma cells expressing various forms of RAGE into mice showed that overexpression of full-length RAGE greatly increased tumor size compared with injection of mock-transfected cells. RAGE inhibition also led to decreased C6 glioma cell proliferation and treatment of C6 glioma cells with soluble RAGE or RAGE-specific antibody suppressed cellular invasion in vitro. Also, treatment of C6 glioma cells with the cytoplasmic tail-deleted RAGE or with soluble RAGE blocked p42/p44 MAPK, p38 MAPK, and Jun N-terminal kinase (JNK) activation, suggesting that the potential activation of three separate MAPK signal pathways is important for tumor invasion. A news & views article by Liotta and Clair discuss the implications of the results.Taguchi, A., Blood, D.C., del Toro, G., Canet, A., Lee, D.C., Qu, W., Tanji, N., Lu, Y., Lalla, E., Fu, C., Hofmann, M.A., Kislinger, T., Ingram, M., Lu, A., Tanaka, H., Hori, O., Ogawa, S., Stern, D.M., and Schmidt, A.M. (2000) Blockade of RAGE-amphoterin signalling suppresses tumour growth and metastases. Nature 405: 354-360. [Online Journal]Liotta, L.A., and Clair, T. (2000) Cancer: Checkpoint for invasion. Nature 405: 287-288. [Online Journal]

Blocking Neuron Migration and Cancer-It's All the RAGE

Amphoterin, a protein found in the extracellular matrix, is required for proper cortical neuron growth in brain development. Amphoterin is a ligand for RAGE, a transmembrane protein found at the growing edge of neurites. Because activated RAGE is important for neurite migration, it is possible that RAGE signaling is also important for aberrant invasion and metastasis in brain cancer. Taguchi et al . find that blocking RAGE activation leads to the suppression of tumor growth and metastases in mice. Injection of C6 glioma cells expressing various forms of RAGE into mice showed that overexpression of full-length RAGE greatly increased tumor size compared with injection of mock-transfected cells. RAGE inhibition also led to decreased C6 glioma cell proliferation and treatment of C6 glioma cells with soluble RAGE or RAGE-specific antibody suppressed cellular invasion in vitro. Also, treatment of C6 glioma cells with the cytoplasmic tail-deleted RAGE or with soluble RAGE blocked p42/p44 MAPK, p38 MAPK, and Jun N-terminal kinase (JNK) activation, suggesting that the potential activation of three separate MAPK signal pathways is important for tumor invasion. A news &amp; views article by Liotta and Clair discuss the implications of the results. Taguchi, A., Blood, D.C., del Toro, G., Canet, A., Lee, D.C., Qu, W., Tanji, N., Lu, Y., Lalla, E., Fu, C., Hofmann, M.A., Kislinger, T., Ingram, M., Lu, A., Tanaka, H., Hori, O., Ogawa, S., Stern, D.M., and Schmidt, A.M. (2000) Blockade of RAGE-amphoterin signalling suppresses tumour growth and metastases. Nature 405 : 354-360. [Online Journal] Liotta, L.A., and Clair, T. (2000) Cancer: Checkpoint for invasion. Nature 405 : 287-288. [Online Journal]