To investigate the inhibitory effect and anti-cancer mechanism of adenovirus mediated IL-24 gene expression on the human U251 glioma cell. U251 glioma cells were infected with Ad-IL-24 at various multiplicity of infection (MOIs). Cell proliferation was determined by MTT assay. Cell apoptosis was detected by flow cytometry and Hochest staining. The transcription of apoptosis-related genes was analyzed by reverse transcription-PCR (RT-PCR), and the expression of Cleaved Caspase-3 was analyzed by Western blotting. The result showed that the growth of U251 glioma cells was significantly inhibited by Ad-IL-24 at the MOI of 100. The apoptotic rate of U251 glioma cells was 42% 72 h after infection with Ad-IL-24. Four days after infection, the growth of the U251 glioma cells was inhibited to 50%. RT-PCR showed that Ad-IL-24 not only up-regulated expression of bax/bcl-2, ICE, C-myc, p53 and down-regulated the expression of HIF-1alpha, but also enhanced Caspase-3 activation, eventually resulting apoptosis. Taken together, these results suggest that infection of U251 glioma cells with Ad-IL-24 can inhibit growth and induce apoptosis significantly by the regulation of apoptosis-related genes.
Adenoviridae ; genetics ; metabolism ; Apoptosis ; Brain Neoplasms ; genetics ; pathology ; Cell Proliferation ; drug effects ; Genetic Therapy ; Glioma ; genetics ; pathology ; Humans ; Interleukins ; genetics ; metabolism ; Recombination, Genetic ; Tumor Cells, Cultured

Malignant glioma is the most frequent type in brain tumors. The prognosis of this tumor has not been significantly improved for the past decades and the average survival of patients is less than one year. Thus, an effective novel therapy is urgently needed. TNF-related apoptosis inducing ligand (TRAIL), known to have tumor cell-specific killing activity, has been investigated as a novel therapeutic for cancers. We have developed Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy and demonstrated the potential to treat malignant gliomas. Currently, this Ad-stTRAIL gene therapy is under phase I clinical trial for malignant gliomas. Here, we report preclinical studies for Ad-stTRAIL carried out using rats. We delivered Ad-stTRAIL intracranially and determined its pharmacokinetics and biodistribution. Most Ad-stTRAIL remained in the delivered site and the relatively low number of viral genomes was detected in the opposite site of brain and cerebrospinal fluid. Similarly, only small portion of the viral particles injected was found in the blood plasma and major organs and tissues, probably due to the brain-blood barrier. Multiple administrations did not lead to accumulation of Ad-stTRAIL at the injection site and organs. Repeated delivery of Ad-stTRAIL did not show any serious side effects. Our data indicate that intracranially delivered Ad-stTRAIL is a safe approach, demonstrating the potential as a novel therapy for treating gliomas.
Adenoviridae/genetics ; Animals ; Blood-Brain Barrier ; Brain/drug effects/*metabolism/pathology ; Brain Neoplasms/genetics/metabolism/pathology/*therapy ; Clinical Trials, Phase I as Topic ; DNA, Viral/metabolism ; Disease Models, Animal ; Drug Delivery Systems ; Drug Evaluation, Preclinical ; *Gene Therapy ; Glioma/genetics/metabolism/pathology/*therapy ; Humans ; Liver/drug effects/metabolism/pathology ; Protein Multimerization/genetics ; Rats ; Spleen/drug effects/metabolism/pathology ; TNF-Related Apoptosis-Inducing Ligand/genetics/*pharmacokinetics

Malignant glioma is the most frequent type in brain tumors. The prognosis of this tumor has not been significantly improved for the past decades and the average survival of patients is less than one year. Thus, an effective novel therapy is urgently needed. TNF-related apoptosis inducing ligand (TRAIL), known to have tumor cell-specific killing activity, has been investigated as a novel therapeutic for cancers. We have developed Ad-stTRAIL, an adenovirus delivering secretable trimeric TRAIL for gene therapy and demonstrated the potential to treat malignant gliomas. Currently, this Ad-stTRAIL gene therapy is under phase I clinical trial for malignant gliomas. Here, we report preclinical studies for Ad-stTRAIL carried out using rats. We delivered Ad-stTRAIL intracranially and determined its pharmacokinetics and biodistribution. Most Ad-stTRAIL remained in the delivered site and the relatively low number of viral genomes was detected in the opposite site of brain and cerebrospinal fluid. Similarly, only small portion of the viral particles injected was found in the blood plasma and major organs and tissues, probably due to the brain-blood barrier. Multiple administrations did not lead to accumulation of Ad-stTRAIL at the injection site and organs. Repeated delivery of Ad-stTRAIL did not show any serious side effects. Our data indicate that intracranially delivered Ad-stTRAIL is a safe approach, demonstrating the potential as a novel therapy for treating gliomas.
Adenoviridae/genetics ; Animals ; Blood-Brain Barrier ; Brain/drug effects/*metabolism/pathology ; Brain Neoplasms/genetics/metabolism/pathology/*therapy ; Clinical Trials, Phase I as Topic ; DNA, Viral/metabolism ; Disease Models, Animal ; Drug Delivery Systems ; Drug Evaluation, Preclinical ; *Gene Therapy ; Glioma/genetics/metabolism/pathology/*therapy ; Humans ; Liver/drug effects/metabolism/pathology ; Protein Multimerization/genetics ; Rats ; Spleen/drug effects/metabolism/pathology ; TNF-Related Apoptosis-Inducing Ligand/genetics/*pharmacokinetics

Although methyltransferase has been recognized as a major element that governs the epigenetic regulation of the genome during temozolomide (TMZ) chemotherapy in glioblastoma multiforme (GBM) patients, its regulatory effect on glioblastoma chemoresistance has not been well defined. This study investigated whether DNA methyltransferase (DNMT) expression was associated with TMZ sensitivity in glioma cells and elucidated the underlying mechanism. DNMT expression was analyzed by western blotting. miR-20a promoter methylation was evaluated by methylation-specific PCR. Cell viability and apoptosis were assessed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and TdT-mediated dUTP-biotin nick end labeling assays, respectively. The results showed that compared with parental U251 cells, DNMT1 expression was downregulated, miR-20a promoter methylation was attenuated and miR-20a levels were elevated in TMZ-resistant U251 cells. Methyltransferase inhibition by 5-aza-2\'-deoxycytidine treatment reduced TMZ sensitivity in U251 cells. In U251/TM cells, DNMT1 expression was negatively correlated with miR-20a expression and positively correlated with TMZ sensitivity and leucine-rich repeats and immunoglobulin-like domains 1 expression; these effects were reversed by changes in miR-20a expression. DNMT1 overexpression induced an increase in U251/TM cell apoptosis that was inhibited by the miR-20a mimic, whereas DNMT1 silencing attenuated U251/TM cell apoptosis in a manner that was abrogated by miR-20a inhibitor treatment. Tumor growth of the U251/TM xenograft was inhibited by pcDNA-DNMT1 pretreatment and boosted by DNMT1-small hairpin RNA pretreatment. In summary, DNMT1 mediated chemosensitivity by reducing methylation of the microRNA-20a promoter in glioma cells.
Animals ; Antineoplastic Agents, Alkylating/*pharmacology/therapeutic use ; Apoptosis/drug effects ; Brain/drug effects/metabolism/pathology ; Brain Neoplasms/drug therapy/*genetics/pathology ; DNA (Cytosine-5-)-Methyltransferase/antagonists & inhibitors/*genetics/metabolism ; DNA Methylation ; Dacarbazine/*analogs & derivatives/pharmacology/therapeutic use ; Drug Resistance, Neoplasm ; Female ; Gene Expression Regulation, Neoplastic ; Glioma/drug therapy/*genetics/pathology ; Humans ; Mice, Inbred C57BL ; MicroRNAs/*genetics ; Promoter Regions, Genetic

Gliomas are extremely aggressive brain tumors with a very poor prognosis. One of the more promising strategies for the treatment of human gliomas is targeted immunotherapy where antigens that are unique to the tumors are exploited to generate vaccines. The approach, however, is complicated by the fact that human gliomas escape immune surveillance by creating an immune suppressed microenvironment. In order to oppose the glioma imposed immune suppression, molecules and pathways involved in immune cell maturation, expansion, and migration are under intensive clinical investigation as adjuvant therapy. Toll-like receptors (TLRs) mediate many of these functions in immune cell types, and TLR agonists, thus, are currently primary candidate molecules to be used as important adjuvants in a variety of cancers. In animal models for glioma, TLR agonists have exhibited antitumor properties by facilitating antigen presentation and stimulating innate and adaptive immunity. In clinical trials, several TLR agonists have achieved survival benefit, and many more trials are recruiting or ongoing. However, a second complicating factor is that TLRs are also expressed on cancer cells where they can participate instead in a variety of tumor promoting activities including cell growth, proliferation, invasion, migration, and even stem cell maintenance. TLR agonists can, therefore, possibly play dual roles in tumor biology. Here, how TLRs and TLR agonists function in glioma biology and in anti-glioma therapies is summarized in an effort to provide a current picture of the sophisticated relationship of glioma with the immune system and the implications for immunotherapy.
Animals ; Antigens, Neoplasm ; chemistry ; immunology ; Antineoplastic Agents ; chemistry ; immunology ; therapeutic use ; Brain Neoplasms ; genetics ; immunology ; pathology ; therapy ; Chemotherapy, Adjuvant ; Clinical Trials as Topic ; Disease Models, Animal ; Gene Expression Regulation, Neoplastic ; drug effects ; immunology ; Glioma ; genetics ; immunology ; pathology ; therapy ; Humans ; Immunotherapy ; methods ; Signal Transduction ; Toll-Like Receptors ; agonists ; genetics ; immunology