C6 Tumor Cells Research Articles

Synthesis and antiproliferative activity of new 1,5-disubstituted tetrazoles bearing hydrazone moiety

A new class of tetrazole-hydrazone derivatives including chloro-substituted phenyl moiety were synthesized to perform anticancer activity screening. The structural elucidation of the compounds was performed by IR, 1H NMR, 13C NMR, MS spectral, and elemental analyses data. Anticancer effect of the compounds was evaluated against A549 and C6 tumor cell lines. MTT, analysis of DNA synthesis and analysis of caspase-3 activation assays were carried out for anticancer activity investigations. Compounds N′-(2-chlorobenzylidene)-4-[(1-phenyl-1H-tetrazole-5-yl)thio]butanohydrazide (3a), N′-(2,3-dichlorobenzylidene)-4-[(1-phenyl-1H-tetrazole-5-yl)thio]butanohydrazide (3d), and N′ -(3,4-dichlorobenzylidene)-4-[(1-phenyl-1H-tetrazole-5-yl)thio]butanohydrazide (3e) showed significant anticancer activity. Anticancer screening tests also indicated that compound 3d has potential on C6 tumor cells with apoptotic pathway.

In Vivo Responses of Human A375M Melanoma to a σ Ligand: 18F-FDG PET Imaging

σ-ligands can kill tumor cells. Previously we have shown that a short in vitro incubation of C6 tumor cells with σ-ligands (24 h) results in a dose-dependent increase of cellular (18)F-FDG uptake and that the magnitude of this increase is predictive of subsequent cell death. Here, we aimed to assess whether the σ-ligand rimcazole inhibits growth of A375M melanoma xenografts in nude mice and whether rimcazole treatment changes (18)F-FDG uptake in vivo. Athymic mice were inoculated with A375M melanoma cells. After 2 wk, tumors had reached a size of 41 ± 6 mm(3). We then started a 14-d treatment schedule with daily drug dosing. Control animals were injected with water and treated animals with rimcazole (26 mg/kg) in water. Three small-animal PET scans with (18)F-FDG were obtained: on days 0, 7, and 14 of treatment. After the last scan, animals were terminated, and a biodistribution study was performed. Rimcazole treatment resulted in a greater than 4-fold reduction of tumor weight in comparison to controls at day 14 (100 ± 26 vs. 436 ± 117 mg, respectively, P < 0.03). Treatment did not affect the levels of (nonradioactive) glucose in blood, σ-1 and σ-2 receptor expression in the tumor, animal weight, behavior, or appearance. Antitumor activity of rimcazole was accompanied by a transient increase of the tumor uptake of (18)F-FDG (measured at day 7). Significant increases of (18)F-FDG uptake at day 14 were observed in the liver and pancreas. Rimcazole strongly inhibited the growth of A375M melanoma xenografts. This growth inhibition is accompanied by an early increase of (18)F-FDG uptake in the tumor.

Glycine administration attenuates skeletal muscle wasting in a mouse model of cancer cachexia

The non-essential amino acid, glycine, is often considered biologically neutral, but some studies indicate that it could be an effective anti-inflammatory agent. Since inflammation is central to the development of cancer cachexia, glycine supplementation represents a simple, safe and promising treatment. We tested the hypothesis that glycine supplementation reduces skeletal muscle inflammation and preserves muscle mass in tumor-bearing mice. To induce cachexia, CD2F1 mice received a subcutaneous injection of PBS (control, n = 12) or C26 tumor cells (n = 32) in accordance with the protocols developed by Murphy et al. [Murphy KT, Chee A, Trieu J, Naim T, Lynch GS. Importance of functional and metabolic impairments in the characterization of the C-26 murine model of cancer cachexia. Dis Models Mech 2012;5(4):533-545.]. Subcutaneous injections of glycine (n = 16) or PBS (n = 16) were administered daily for 21 days and at the conclusion of treatment, selected muscles, tumor and adipose tissue were collected and prepared for Real-Time RT-PCR or western blot analysis. Glycine attenuated the loss of fat and muscle mass, blunted increases in markers of inflammation (F4/80, P = 0.01 & IL-6 mRNA, P = 0.01) and atrophic signaling (MuRF, P = 0.047; atrogin-1, P = 0.04; LC3B, P = 0.06 and; BNIP3, P = 0.10) and tended to attenuate the loss of body mass (P = 0.07), muscle function (P = 0.06), and oxidative stress (GSSG/GSH, P = 0.06 and DHE, P = 0.07) seen in tumor-bearing mice. Preliminary studies that compared the effect of glycine administration with isonitrogenous doses of alanine or citrulline showed that the observed protective effect was specific to glycine. Glycine protects skeletal muscle from cancer-induced wasting and loss of function, reduces the oxidative and inflammatory burden, and reduces the expression of genes associated with muscle protein breakdown in cancer cachexia. Importantly, these effects were glycine specific.

Synthesis and Biological Evaluation of Some 1,2‐Disubstituted Benzimidazole Derivatives as New Potential Anticancer Agents

The synthesis of some new 1-(2-aryl-2-oxoethyl)-2-[(morpholine-4-yl)thioxomethyl]benzimidazole derivatives and investigation of their anticancer activities were the aims of this work. 2-(Chloromethyl)benzimidazole compound was reacted with sulfur and morpholine via Willgerodt-Kindler reaction to give 2-[(morpholine-4-yl)thioxomethyl]benzimidazole. Then, the obtained compound was reacted with appropriate α-bromoacetophenone derivatives in the presence of potassium carbonate to give the final products. Structure elucidation of the final compounds was achieved by FT-IR, (1)H NMR spectroscopy and MS spectrometry. The anticancer activities of the final compounds were evaluated by MTT assay, BrdU method, and flow cytometric analysis on C6, MCF-7, and A549 tumor cells. Most of the synthesized compounds exhibited considerable selectivity against the MCF-7 and C6 cell lines.

Synthesis and anticancer activity evaluation of N-[4-(2-methylthiazol-4-yl)phenyl]acetamide derivatives containing (benz)azole moiety

A new class of novel thiazole-(benz)azole derivatives was synthesized to investigate their anticancer activity. The structure of the compounds was confirmed by IR, 1H-NMR, and MS spectral data and elemental analyses. Anticancer effect of the compounds was evaluated against A549 and C6 tumor cell lines. MTT, analysis of DNA synthesis, acridine orange/ethidium bromide staining method and analysis of caspase-3 activation assays were performed for anticancer activity investigations. Compounds 6f and 6g, which carry 5-chloro and 5-methylbenzimidazole groups showed significant anticancer activity. Potential of these compounds to direct tumor cells to apoptotic pathway, which is a precondition of anticancer action, was also observed.

Simple and convenient preparation of novel 6,8-disubstituted quinoline derivatives and their promising anticancer activities

A short and easy route is described for 6,8-disubstituted derivatives of quinoline and 1,2,3,4-tetrahydroquinoli- ne from 6,8-dibromoquinolines 2 and 7 by various substitution reactions. While copper-promoted substitution of 6,8-dibromide 2 produced monomethoxides 3 and 4, a prolonged reaction time mainly afforded dimethoxide 6 instead of 5, whose aromatization with DDQ and substitution reaction of dibromide 7 with NaOMe in the presence of CuI also gave rise to dimethoxide 6. Several 6,8-disubstituted quinolines were obtained by treatment of 6,8-dibromoquinoline (7) with n-BuLi followed by trapping with an electrophile [Si(Me)_3Cl, S_2(Me)_2, and DMF]. Furthermore, 7 was also converted to mono and dicyano derivatives. The anticancer activities of compounds 2, 7, 6, 12, 13, 15, and 16 against HeLa, HT29, and C6 tumor cell lines were tested, and 6,8-dibromo-1,2,3,4-tetrahydroquinoline (2) and 6,8-dimethoxyquinoline (6) showed significant anticancer activities against the tumor cell lines.

Determination of anticancer activities of some quinoline derivatives against C6 tumor cells

Determination of anticancer activities of some quinoline derivatives against C6 tumor cells

477P - Liposomal Prodrug of Mitomycin C with Thiolytic Activation: Improved Therapeutic Index Over Mitomycin C in Preclinical Studies

ABSTRACT Disclosure A.A. Gabizon: I am the founder and Chief Scientist of Lipomedix Inc., a company with a vested interest in the product discussed in this presentation. Y. Amitay: Paid employee of Lipomedix, a product of which is discussed here. All other authors have declared no conflicts of interest. We have developed a formulation of a mitomycin-C lipid-based prodrug (MLP) in pegylated liposomes (PL) in which MLP is activated by thiolytic cleavage to mitomycin C (MMC). PL-MLP (PROMITIL™) was previously reported to have reduced toxicity and an improved therapeutic index as compared to MMC in human and mouse tumor models. In the following studies, we examined the pharmacokinetics, toxicity, and therapeutic activity of scaled-up batches of PL-MLP (prepared under the same protocol design as for clinical batches) in rodent and miniswine species. PL-MLP is a liquid suspension of vesicles of ∼100 nm diameter with MLP entrapped in the lipid bilayer at 10% molar ratio. Pharmacokinetic studies revealed major (>100-fold) differences in Cmax, AUC, plasma clearance and volume of distribution between MMC (i.v. 3 mg/kg) and PL-MLP (i.v. 6 mg/kg in MMC-equivalents). While MMC is cleared from blood within minutes and extensively distributed to peripheral tissues, PL-MLP is cleared very slowly with a mono-exponential half-life of ∼15 hours in rats and has a limited volume distribution roughly equivalent to the blood volume. In rat toxicity studies in rats, the MTD of PL-MLP was two to three-fold higher than that of MMC in mg-equivalent doses. Therapeutic studies in BALB/c mice inoculated i.p. with C26 tumor cells show a clear survival advantage for treatment with PL-MLP over free MMC at all dose levels tested, whether treatment was administered by the i.v. or by the i.p. route. In the porcine model, no acute infusion reaction to i.v. administration of PL-MLP was observed. PL-MLP appears to be a stable formulation with minimal prodrug activation and release of MMC in circulation, yet significant antitumor activity, indicating in vivo prodrug activation in tumors. PL-MLP may represent an effective therapeutic tool in a broad spectrum of malignancies, including multi-drug resistant tumors, with improved safety over free MMC, and is due to be tested in a human phase I study in 2012.

Immunotherapy of rat glioma without accumulation of CD4(+)CD25(+)FOXP3(+) regulatory T cells.

Immunotherapy may be used for the treatment of glioblastoma multiforme; however, the induced immune response is inadequate when either T cells or dendritic cells are used alone. In this study, we established a novel vaccine procedure in rats, using dendritic cells pulsed with C6 tumor cell lysates in combination with adoptive transfer of T lymphocytes from syngenic donors. On day 21 after tumor inoculation, all the rats were sacrificed, the brains were harvested for calculation of glioma volume, cytolytic T lymphocyte responses were measured by cytotoxic assay, and the frequency of regulatory T lymphocytes (CD4+CD25+FOXP3+) in the peripheral blood was investigated by flow cytometric analysis. The survival rate of rats bearing C6 glioma was observed. Results showed that the co-immunization strategy had significant anti-tumor potential against the pre-established C6 glioma, and induced a strong cytolytic T lymphocyte response in rats. The frequency of peripheral blood CD4+CD25+FOXP3+ regulatory T lymphocytes was significantly decreased following the combination therapy, and the rats survived for a longer period. Experimental findings indicate that the combined immunotherapy of glioma cell lysate-pulsed dendritic cell vaccination following adoptive transfer of T cells can effectively inhibit the growth of gliomas in rats, boost anti-tumor immunity and produce a sustained immune response while avoiding the accumulation of CD4+CD25+FOXP3+ regulatory T lymphocytes.

The Importance of Testes Function in Mouse Models of Cachexia

Hallmarks of cancer cachexia include chronic inflammation, insulin resistance and hypogonadism. Genetic and tumor implantation mouse models are methods used to study cancer cachexia. The purpose of this study was to explore the relationship between gonadal function and body weight (BW) loss in two mouse models of cachexia. Experiment 1: BALB/c mice were implanted with C26 tumor cells and monitored for 29 days. BW, testes weight, and circulating testosterone decreased in tumor bearing mice (p &lt; 0.05). Experiment 2: Male ApcMin/+ (Min) mice were sacrificed at either 12, 14, or 20 weeks of age. Min BW, testes weight, and circulating testosterone decreased between 14 and 20 weeks of age (p &lt;0.05). Testes expression of androgen receptor protein decreased, while Bax protein and pSTAT(Tyr705) increased between 14 and 20 weeks of age (p &lt; 0.05). Testosterone levels and testes weight were correlated with BW loss in the Min mouse. Experiment 3: Male Min and C57BL/6 mice were treated with an IL‐6 receptor antibody or PBS control at 16 weeks of age for 2 weeks. Although cachexia decreased testes weight and circulating testosterone, IL‐6 receptor antibody administration attenuated these changes. In the C26 and Min mouse models of cachexia, decreased circulating testosterone appears to be an important regulatory event for the progression of the disease. Funded by NCI R01‐CA121249

S-Nitrosated Human Serum Albumin Dimer is not only a Novel Anti-Tumor Drug but also a Potentiator for Anti-Tumor Drugs with Augmented EPR Effects

Macromolecules have been developed as carriers of low-molecular-weight drugs in drug delivery systems (DDS) to improve their pharmacokinetic profile or to promote their uptake in tumor tissue via enhanced permeability and retention (EPR) effects. In the present study, recombinant human serum albumin dimer (AL-Dimer), which was designed by linking two human serum albumin (HSA) molecules with the amino acid linker (GGGGS)(2), significantly accumulated in tumor tissue even more than HSA Monomer (AL-Monomer) and appearing to have good retention in circulating blood in murine colon 26 (C26) tumor-bearing mice. Moreover, we developed S-nitrosated AL-Dimer (SNO-AL-Dimer) as a novel DDS compound containing AL-Dimer as a carrier, and nitric oxide (NO) as (i) an anticancer therapeutic drug/cell death inducer and (ii) an enhancer of the EPR effect. We observed that SNO-AL-Dimer treatment induced apoptosis of C26 tumor cells in vitro, depending on the concentration of NO. In in vivo experiments, SNO-AL-Dimer was found to specifically deliver large amounts of cytotoxic NO into tumor tissue but not into normal organs in C26 tumor-bearing mice as compared with control (untreated tumor-bearing mice) and SNO-AL-Monomer-treated mice. Intriguingly, S-nitrosation improved the uptake of AL-Dimer in tumor tissue through augmenting the EPR effect. These data suggest that SNO-AL-Dimer behaves not only as an anticancer therapeutic drug, but also as a potentiator of the EPR effect. Therefore, SNO-AL-Dimer would be a very appealing carrier for utilization of the EPR effect in future development of cancer therapeutics.

Early Detection of Tumor Response by FLT/MicroPET Imaging in a C26 Murine Colon Carcinoma Solid Tumor Animal Model

Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging demonstrated the change of glucose consumption of tumor cells, but problems with specificity and difficulties in early detection of tumor response to chemotherapy have led to the development of new PET tracers. Fluorine-18-fluorothymidine (18F-FLT) images cellular proliferation by entering the salvage pathway of DNA synthesis. In this study, we evaluate the early response of colon carcinoma to the chemotherapeutic drug, lipo-Dox, in C26 murine colorectal carcinoma-bearing mice by 18F-FDG and 18F-FLT. The male BALB/c mice were bilaterally inoculated with 1 × 105 and 1 × 106 C26 tumor cells per flank. Mice were intravenously treated with 10 mg/kg lipo-Dox at day 8 after 18F-FDG and 18F-FLT imaging. The biodistribution of 18F-FDG and 18F-FLT were followed by the microPET imaging at day 9. For the quantitative measurement of microPET imaging at day 9, 18F-FLT was superior to 18F-FDG for early detection of tumor response to Lipo-DOX at various tumor sizes (P < 0.05). The data of biodistribution showed similar results with those from the quantification of SUV (standard uptake value) by microPET imaging. The study indicates that 18F-FLT/microPET is a useful imaging modality for early detection of chemotherapy in the colorectal mouse model.

Bioavailability of magnetic nanoparticles to the brain

This study investigates the bioavailability of carboxymethyl dextran-coated magnetic nanoparticles (CMD-MNP) to the brain. The cytotoxicity of CMD-MNP was assessed by co-culture with C6, a rat glioma cell line. To investigate the effects of an external magnetic field on the biodistribution of nanoparticles in a rat model, a magnet of 0.3 Tesla was applied externally over the cranium and the particles injected via the external jugular vein. Nanoparticles were also injected into rats implanted with C6 tumor cells. Staining of histological samples with Prussian blue to detect iron particles revealed that the external magnetic field enhanced the aggregation of nanoparticles in the rat brain; this enhancement was even more pronounced in the tumor region.

Beneficial immune modulatory effects of a specific nutritional combination in a murine model for cancer cachexia

The majority of patients with advanced cancer are recognised by impaired immune competence influenced by several factors, including the type and stage of the tumour and the presence of cachexia. Recently, a specific nutritional combination containing fish oil, specific oligosaccharide mixture, high protein content and leucine has been developed aimed to support the immune system of cancer patients in order to reduce the frequency and severity of (infectious) complications. In a recently modified animal model cachexia is induced by inoculation of C26 tumour cells in mice. In a pre-cachectic state, no effect was observed on contact hypersensitivity, a validated in vivo method to measure Th1-mediated immune function, after adding the individual nutritional ingredients to the diet of tumour-bearing mice. However, the complete mixture resulted in significantly improved Th1 immunity. Moreover, in a cachectic state, the complete mixture reduced plasma levels of pro-inflammatory cytokines and beneficially affected ex vivo immune function. Accordingly, the combination of the nutritional ingredients is required to obtain a synergistic effect, leading to a reduced inflammatory state and improved immune competence. From this, it can be concluded that the specific nutritional combination has potential as immune-supporting nutritional intervention to reduce the risk of (infectious) complications in cancer patients.

Dysregulation of lipid metabolism in cardiac muscle of mice with cachexia

Approximately 30% of all cancer deaths are caused by cachexia, a condition of severe muscle loss and abnormal lipid metabolism. The objective of this study was to elucidate events that lead to impaired lipid metabolism and muscle wasting in cardiac muscle of mice exhibiting cancer‐induced muscle atrophy. In male CD2F1 mice injected with C26 tumor cells, body weight and mass of quadriceps, gastrocnemius and heart were significantly reduced after 18 days compared to mice injected with vehicle. In the highly oxidative cardiac muscle of mice bearing tumors, phosphorylated‐AMP dependent kinase (AMPK) was elevated. However, a rate limiting enzyme in β‐oxidation, carnitine palmitoyl transferase‐1β (CPT‐1β) mRNA expression was reduced by 40% while peroxisome proliferator‐activated receptor α (PPARα) mRNA was reduced by 35%. In contrast, mRNA levels of lipoprotein lipase (LPL) and adipose triglyceride lipase (ATGL) were induced, suggesting increased fatty acid uptake and lipolysis. Unexpectedly, uncoupling protein 2 (UCP2) mRNA was induced 5.3 fold. Activated AMPK with increased fatty acid uptake without induction of markers of β‐oxidation suggest that downstream events of AMPK are dysregulated in cachexia‐induced atrophy of cardiac muscle. Further work will determine whether induction of UCP2 alleviates reactive oxygen species (ROS) and results in thermogenesis. Supported by Cognis Corporation and OARDC.

Single administration of low dose cyclophosphamide augments the antitumor effect of dendritic cell vaccine.

Single administration of low dose cyclophosphamide (CTX) was previously reported to enhance the antitumor efficacy of immunotherapies. To investigate the possible mechanisms for this effect, we examined whether a single administration of low dose CTX could augment the immunogenicity of dendritic cell (DC) vaccines. Fifty milligrams per kilogram body weight dose of CTX was administrated intraperitoneally to mice after B16 melanoma or C26 colon carcinoma tumor models were established, DC vaccine generated from mouse bone marrow and pulsed with B16 or C26 tumor cells lysates were vaccinated 4 days later. CTX treatment potentiated the antitumor effects of the DC vaccine, and increased the proportion of IFN-gamma secreting lymphocytes in spleens. Furthermore, a significantly reduced proportion of CD4+CD25+FoxP3+ regulatory T (Treg) cells was detected by flow cytometry in spleen lymphocytes from tumor-bearing mice treated with CTX. Thus, a single administration of low dose CTX could augment antitumor immune responses of DC vaccine by reducing the proportion of CD4+CD25+FoxP3+ Treg cells in tumor-bearing mice. Our results suggested a possible mechanism of CTX-induced immunopotentiation and provided a strategy of immunotherapy combining a low dose CTX with DC vaccine.

Immunotherapy with dendritic cells and CpG oligonucleotides can be combined with chemotherapy without loss of efficacy in a mouse model of colon cancer

Although immunotherapy has shown promising results in the treatment of cancer, clinical studies assessing immunologic approaches in patients with advanced cancer will seldom be conducted in the absence of conventional treatment strategies such as chemotherapy. Here we investigate the combination of chemotherapy with CpG oligonucleotide and dendritic cell-based immunotherapy in the C26 mouse model of colon carcinoma. The coinjection of antigen-pulsed, mature dendritic cells and CpG oligonucleotides together with a peritumoral injection of CpG oligonucleotides elicits a CD8 T-cell response resulting in tumor rejection and long-term protection in the C26 model. Tumor-bearing mice were treated weekly for 4 weeks by this immunotherapy protocol, by 5-fluorouracil plus leucovorin or irinotecan, or by the combination of immunotherapy and chemotherapy. We observed that immunotherapy was more effective in reducing tumor growth and increasing survival than 5-fluorouracil or irinotecan. Immunotherapy was well tolerated, whereas therapeutic doses of 5-fluorouracil or irinotecan were associated with dose-limiting toxicity. Furthermore, the efficacy of immunotherapy combined with either 5-fluorouracil or irinotecan was similar to that of immunotherapy alone. Addition of immunotherapy to either 5-fluorouracil or irinotecan treatment strongly decreased the toxicity of chemotherapy. Immunotherapy both with and without chemotherapy generated a memory immune response, leading to tumor rejection in mice rechallenged with C26 tumor cells up to several months after treatment. In summary, immunotherapy with a combination of dendritic cells and CpG oligonucleotides is superior to chemotherapy in the C26 tumor model. This immunotherapy protocol can be combined with current chemotherapy agents with no loss in therapeutic activity.

Tetrazolium violet induces G0/G1 arrest and apoptosis in brain tumor cells

Tetrazolium violet (TV), a potent anticancer agent, has been shown to induce cell growth-inhibition in tumor cells. However, the related mechanism has not been revealed yet. In this report we assessed the influence of TV on cell growth and cell cycle in brain tumor cells. Treatment of C6 tumor cells with TV (5-15 microM for 24-72 h) resulted in a growth inhibition in a dose and time-dependent manner and G0/G1 phase arrest, determined by flow cytometry analysis. These effects were accompanied by apoptosis other than necrosis, evidenced by nuclear condensation, terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay and trypan blue exclusion assay plus lactate dehydrogenase (LDH) release assay. Treatment of cells with TV at 15 microM for 24 h resulted in an increase in the activity of caspase-3, evidenced by colorimetric assay, and a dramatic up-regulation of p53, accompanied with a significant increase of Bax/Bcl-2 ratio, as evidenced by immunofluorescence assay. These results suggest that TV induces growth inhibition of C6 cells through p53-midiated apoptotic pathway and G0/G1 checkpoint mechanism. Although detailed mechanisms remain to be explored, selective blockage of tumor cells in G0/G1 phase accompanied by p53-associated apoptosis makes tetrazolium violet a promising anticancer agent, meriting further investigations.

Sensitization to Apoptosis Underlies Kras D12 -Dependent Oncolysis of Murine C26 Colorectal Carcinoma Cells by Reovirus T3D

Reovirus T3D is an oncolytic agent that preferentially targets tumor cells expressing an activated Ras oncogene. Ras signaling interferes with the cellular stress response that inhibits translation of reovirus RNAs. Murine C26 colorectal carcinoma cells express a mutant KrasD12 gene. Reovirus T3D efficiently kills C26 cells, but not C26 cells in which the KrasD12 mRNA is stably repressed by expression of KrasD12-directed short-hairpin RNAs. Surprisingly, neither reovirus T3D protein synthesis nor T3D virus yields were suppressed by deletion of KrasD12. Rather, reovirus-induced tumor cell apoptosis was completely abrogated as a result of Kras knockdown. We conclude that sensitization of C26 tumor cells to reovirus-induced apoptosis underlies the Ras dependency of reovirus T3D oncolysis.

An experimental study of dendritic cells-mediated immunotherapy against intracranial gliomas in rats

To investigate the effect of dendritic cells(DC) pulsed with apoptotic tumor cells for treatment of intracranial gliomas in rats. C6 glioma cells were injected into brain of Wistar rats under stereotactic monitor to establish an animal model of glioma. The precursors of DCs were isolated from bone marrow of rats, stimulated in vitro with recombinent rat granulocyte-macrophage colony-stimulating factor (rrGM-CSF) and interleukin-4 (rrIL-4). These DCs were then pulsed ex vivo with apoptotic C6 glioma cells induced by heating and subsequently injected subcutaneously into rats harboring intracranial C6 glioma. Rats were treated with five weekly subcutaneous injections of either control media, unpulsed DCs, or DCs pulsed with apoptotic tumor cells. The animals were followed for survival, volume of tumor by MRI, CD8 + T cells, cytotoxicity assay in vitro and proliferational function of lymphocytes in peripheral blood were determined by flow cytometry(FCM). The concentration of cytokines interferon-gamma (IFN-gamma) and interleukin-10(IL-10) were monitored through enzyme-linked immunosorbent assay(ELISA) using ELISAkit. Our results indicated that C6 glioma model rats treated with apoptotic tumor cells pulsed DCs prolonged survival, inhibited the tumor growth and increased the level of CD8 + T lymphocytes in peripheral blood comparing with control group. Cytotoxicity assay suggested that vaccination with these apoptotic cells pulsed DCs can induce cytotoxic T lymphocytes response against C6 tumor cells compared with control group. Furthermore, significantly enhanced IFN-gamma and reduced IL-10(even undetectable) were observed in peripheral blood of rats treated with pulsed-DCs. No evident autoimmune response were detected. Our data demonstrated that systemic vaccination with DCs pulsed with apoptotic cells is a safe and effective immunotherapy for intracranial glioma.