Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two obstacles limiting the efficacy of nearly all cancer gene therapy trails are low gene transduction efficiency and the lack of tumor specificity. Fortunately, a replication-competent, E1B-deficient adenovirus (dl1520) was developed that could overcome these limitations, because it was capable of efficiently and selectively destroying tumor cells lacking functional p53. In an attempt to appraise the efficiency and safety of this approach, a novel recombinant adenovirus, r3/Ad, containing a gfp-zeocin expression cassette was constructed in this work. The study in vitro demonstrated that r3/Ad has the ability to replicate in and lyse only the p53-deficient human tumor cells such as the human glioblastoma cells (U251) and human bladder cells (EJ) but not in the human fibroblast cells (MRC-5) with functional p53. Importantly, this gfp-zeocin fusion gene driven by the bipromoter (CMV and EM-7) could be used as an effective selective marker and reporter in prokaryotic and eukaryotic cells; and also zeocin as a selective marker could minimize contamination of the recombinant virus by the wt-Ad5. Additionally, it was found that the r3/Ad could be useful for studying the selective replication of E1B-deficient adenovirus in vivo, it could be used as a "guide" to study the ability of the recombinant adenovirus to spread and to infect distant tumor cells in any tumor bearing animal model by GFP as a reporter. This may help determine the safety of using any E1B-deficient adenovirus in cancer gene therapy.
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PMID:Development of a novel recombinant adenovirus containing gfp-zeocin fusion expression cassette for conditional replication in p53-deficient human tumor cells. 1504 Dec 9

The adenoviral protein E4orf6 has been shown to inhibit both in vitro V(D)J recombination and adenoviral DNA concatenation, two processes that rely on cellular DNA double strand break repair (DSBR) proteins. Most of the known activities of E4orf6 during adenoviral infection require its interaction with another adenoviral protein, E1B-55K. Here we report that E4orf6, stably expressed in RKO human colorectal carcinoma cells or transiently expressed by adenoviral vector in U251 human glioblastoma cells, inhibits DSBR and induces significant radiosensitization in the absence of E1B-55K. Expression of a mutant form of E4orf6 (L245P) failed to radiosensitize RKO cells. E4orf6 reduced DSBR capacity in transfected and infected cells, as measured by sublethal DNA damage repair assay and phosphorylated H2AX (gamma-H2AX) levels, respectively. Consistent with the inhibitory effect of E4orf6 on DSBR, expression of wild-type but not mutant E4orf6 reduced recovery of a transfected, replicating reporter plasmid (pSP189) in 293 cells but did not increase the mutation frequency measured in the reporter plasmid. The kinase activity of DNA-PKcs (the DNA-dependent protein kinase catalytic subunit) toward heterologous substrates was not affected by expression of E4orf6; however, autophosphorylation of DNA-PKcs at Thr-2609 following ionizing radiation was prolonged in the presence of E4orf6 when compared with control-infected cells. Our results demonstrate for the first time that E4orf6 expression hinders the cellular DNA repair process in mammalian cells in the absence of E1B-55K or other adenoviral genes and suggest that viral-mediated delivery of E4orf6, combined with localized external beam radiation, could be a useful approach for the treatment of radioresistant solid tumors such as glioblastomas.
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PMID:The adenovirus E4orf6 protein inhibits DNA double strand break repair and radiosensitizes human tumor cells in an E1B-55K-independent manner. 1550 30

Replication-competent oncolytic viruses are being developed for human cancer therapy. We previously reported that an attenuated adenovirus (OBP-301, 'Telomelysin'), in which the hTERT promoter element drives expression of E1A and E1B genes linked with an IRES, could replicate in cancer cells, and causes selective lysis of cancer cells. We further constructed OBP-405 ('Telomelysin-RGD') that contains an RGD motif in the HI loop of the fiber knob. We examined whether OBP-405 could be effective in overcoming the limitations of OBP-301, specifically their inefficient infection into cells lacking the primary receptor, the coxsackievirus and adenovirus receptor (CAR). By flow cytometric analysis, H1299 (lung) and SW620 (colorectal) tumor cells showed high levels of CAR expression, whereas LN444 (glioblastoma), LNZ308 (glioblastoma), and H1299-R5 (lung) tumor cells were negative for CAR expression. A quantitative real-time PCR analysis demonstrated that fiber-modified OBP-405 infected more efficiently than OBP-301, although the intracellular replication rate of both viruses was consistent. The comparative antitumor effect of fiber-modified OBP-405 and unmodified OBP-301 for human cancer cells was evaluated in vitro by XTT assay as well as in vivo by using athymic mice carrying xenografts. OBP-405 had a profound oncolytic effect on human cancer cell lines compared to OBP-301, in particular on cells with low CAR expression. Intratumoral injection of 10(7) plaque-forming units of OBP-405 into CAR-negative H1299-R5 lung tumor xenografts in nu/nu mice resulted in a significant inhibition of tumor growth and long-term survival in all treated mice. Moreover, selective replication of OBP-405 in the distant, uninjected H1299-R5 tumors was demonstrated. Our results suggest that fiber-modified replication-competent adenovirus OBP-405 exhibits a broad target range by increasing infection efficiency, an outcome that has important implications for the treatment of human cancers.
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PMID:Enhanced oncolysis by a tropism-modified telomerase-specific replication-selective adenoviral agent OBP-405 ('Telomelysin-RGD'). 1573 29

In this study we have made novel observations with regards to potentiation of the tumoricidal activity of the oncolytic adenovirus, dl1520 (ONYX-015) in rat glioblastoma cell lines expressing heat shock protein 72 (HSP72) due to permissive virus replication. ONYX-015 is a conditionally replicating adenovirus that is deleted for the E1B 55 kDA gene product whose normal function is to interact with cell-cycle regulatory proteins to permit virus replication. However, many murine and rodent cell lines are not permissive for adenovirus replication. Previously, it has been reported that the heat shock response is necessary for adenovirus replication and that induction of heat shock proteins is mediated by E1 region gene products. Therefore, we hypothesized that HSP72 expression may allow for permissive replication of ONYX-015 in previously non-permissive cells. Rat glioma cell lines 9L and RT2 were transfected with a plasmids expressing HSP72 or GFP. After infection with ONYX-015, no tumoricidal activity is observed in GFP expressing cell lines despite adequate transduction. In contrast, HSP72 transfected cells show cytopathic effects by 72 hours and greater than 75% loss of viability by 96 hours. Burst assays show active virus replication in the HSP72 expressing cell lines. Therefore, 9L-HSP72 and RT2-HSP72 are ideal models to evaluate the efficacy of ONYX-015 in an immunocompetent rat model. Our study has implications for creating rodent tumor models for pre-clinical studies with E1 region deleted conditionally replicating adenovirus.
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PMID:Heat shock protein 72 expression allows permissive replication of oncolytic adenovirus dl1520 (ONYX-015) in rat glioblastoma cells. 1576 88

E1 region replacement adenoviruses are replication defective and are propagated in cells providing adenovirus E1A and E1B proteins. Although they are being developed for antitumor therapies, the proliferative behaviors of these viruses in normal brain tissues or in brain tumors are unknown. To address this, freshly cultured cells from normal human brain and common brain tumors (astrocytomas and meningiomas) were infected using wild-type species C adenoviruses and adenoviruses missing E1A (H5dl312) or E1A plus E1B (H5dl434). Viral DNA replication, late viral protein expression, and production of infectious progeny were characterized. Wild-type adenoviruses grew efficiently in normal brain and brain tumor cells. In comparison, E1-deleted adenovirus DNA replication was delayed and lower in cells derived from normal brain tissues, meningiomas, and low-grade astrocytomas. However, in contrast, E1-deleted adenovirus DNA replication did not occur or was extremely low in cells derived from malignancy grade III and IV astrocytic tumors. Because wild-type adenoviruses infected and replicated in all cells, the malignancy grade-based differential E1-deleted adenovirus DNA replication was not explained by differential virus uptake. Infectious H5dl312 and H5dl434 production correlated with viral DNA replication. Compared with a 5-day average for wild-type infections, advanced cytopathology was noted approximately 4 weeks after H5dl312 or H5dl434 infection of meningioma, astrocytoma, and normal brain cells. Cytopathology was not observed after H5dl312 or H5dl434 infection of glioblastoma, anaplastic astrocytoma, and gliosarcoma cells. Because of this tumor grade-based differential growth, the E1-deleted adenoviruses may represent novel tools for studies of brain tumor malignancy.
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PMID:Decreased replication ability of E1-deleted adenoviruses correlates with increased brain tumor malignancy. 1620 66

In addition to intrinsic regulatory mechanisms, brain tumor stemlike cells (BTSCs), a small subpopulation of malignant glial tumor-derived cells, are influenced by environmental factors. Previous reports showed that lowering oxygen tension induced an increase of BTSCs expressing CD133 and other stem cell-related genes and more pronounced clonogenic capacity in vitro. We investigated the mechanisms responsible for hypoxia-dependent induction of CD133-positive BTSCs in glioblastomas. We confirmed that cultures exposed to lowered oxygen levels showed a severalfold increase of CD133-positive BTSCs. Both the increase of CD133-positive cells and deceleration of the growth kinetics were reversible after transfer to normoxic conditions. Exposure to hypoxia induced BNIP3 (BCL2/adenovirus E1B 19-kDa protein-interacting protein 3)-dependent apoptosis preferentially in CD133-negative cells. In contrast, CD133-positive cells proved to be more resistant to hypoxia-induced programmed cell death. Application of the demethylating agent 5'-azacitidine resulted in an increase of BNIP3 expression levels in CD133-positive cells. Thus, epigenetic modifications led to their better survival in lowered oxygen tension. Moreover, the, hypoxia-induced increase of CD133-positive cells was inhibited after 5'-azacitidine treatment. These results suggest the possible efficacy of a novel therapy for glioblastoma focused on eradication of BTSCs by modifications of epigenetic regulation of gene expression.
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PMID:Resistance to hypoxia-induced, BNIP3-mediated cell death contributes to an increase in a CD133-positive cell population in human glioblastomas in vitro. 2314 6

Plant lectins have been considered as possible anti-tumor drugs because of their property to induce autophagic cell death. Given that expression of membrane type-1 matrix metalloproteinase (MT1-MMP) has been found to regulate expression of the autophagy biomarker Bcl-2/adenovirus E1B 19kDa interacting protein 3 (BNIP3), we sought to investigate possible signaling interplay mechanisms between MT1-MMP and BNIP3 in Concanavalin-A (ConA) lectin-activated U87 glioblastoma cells. ConA induced acidic vacuole organelle formation as well as BNIP3 and MT1-MMP gene and protein expressions, whereas only BNIP3 expression was dose-dependently inhibited by the JAK2 tyrosine kinase inhibitor AG490 suggesting a requirement for some STAT-mediated signaling. Gene silencing of MT1-MMP and of STAT3 abrogated ConA-induced STAT3 phosphorylation and BNIP3 expression. Correlative analysis shows that STAT3 signaling events occur downstream from MT1-MMP induction. Overexpression of a full length MT1-MMP recombinant protein led to increased BNIP3 gene and protein expressions. The cytoplasmic domain of MT1-MMP was also found necessary for transducing STAT3 phosphorylation. Among JAK1, JAK2, JAK3, and TYK2, only JAK2 gene silencing abrogated ConA's effects on MT1-MMP and BNIP3 gene and protein expressions. Our study elucidates how MT1-MMP signals autophagy, a process which could contribute to the chemoresistance phenotype in brain cancer cells.
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PMID:Induction of autophagy biomarker BNIP3 requires a JAK2/STAT3 and MT1-MMP signaling interplay in Concanavalin-A-activated U87 glioblastoma cells. 2446 46