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

Hypoxia is a common feature of many malignant neoplasms and has been identified as a major reason for the radioresistance of malignant tumor tissue. On the other hand, the transcription factor hypoxia-inducible factor-1 (HIF-1) has attracted attention because it is rapidly expressed when tissue oxygen tension is reduced, thus playing the role of a hypoxic sensor. We investigated whether the level of HIF-1 expression in glioblastoma (GBM) could be an indicator in a protocol for postoperative radiotherapy. We immunohistologically evaluated the level of HIF-1 expression in 60 pathologically diagnosed GBMs. HIF-1 expression was positive in all tumors. The progression-free survival of the group receiving only conventional radiotherapy after surgery differed significantly according to the level of HIF-1 expression. The results of this study suggest that the HIF-1 expression level can be an indicator of tumor radioresistance, and that prior knowledge of the HIF-1 expression level allows the formulation of a protocol for postoperative radiotherapy.
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PMID:Protocol of radiotherapy for glioblastoma according to the expression of HIF-1. 1569 61

Efaproxiral [RSR 13, GSJ 61, JP 4, KDD 86, RS 4] is a synthetic, small-molecule, radiation-sensitising agent being developed by Allos Therapeutics primarily for the treatment of cancer. It works by binding and allosterically stabilising deoxyhaemoglobin in hypoxic regions of tumour tissue. This increases oxygen uptake of the tumour tissue and restores its sensitivity to radiation therapy, making therapy potentially more successful. This first-of-its-class compound is particularly applicable for the treatment of certain tumour types that lack oxygen, such as brain metastases. In contrast to conventional chemotherapeutic agents or radiation sensitisers, there is no requirement for efaproxiral to be administered directly into tumours or to cross the blood-brain barrier for it to display efficacy. Efaproxiral is under review for approval in the US and EU as an adjunct to whole-brain radiation therapy (WBRT) for the treatment of brain metastases originating from breast cancer. It is also under clinical evaluation for a variety of other cancers, including glioblastoma, non-small cell lung cancer (NSCLC) and cervical cancer. Allos is seeking partnership opportunities for efaproxiral's development and marketing. The company has indicated that the development of efaproxiral would be in cooperation with a corporate partner, according to its 2003 Annual Report. In 1994, Allos Therapeutics acquired exclusive worldwide rights to intellectual property relating to efaproxiral from the Center for Innovative Technology (CIT). Allos has entered into arrangements with two contract manufacturers for the supply of efaproxiral, and a third manufacturer for the supply of the formulated drug product. Hovione FarmaCiencia is the primary supplier of efaproxiral, and is contracted to manufacture sufficient quantities on a commercial scale. In addition, a second manufacturer, Raylo Chemicals, is also producing quantities of efaproxiral. In December 2003, Allos entered into a long-term development and supply agreement with Baxter Healthcare who will formulate the efaproxiral into an injection. Allos is also seeking to establish an alternate supplier of efaproxiral injection. Allos submitted a rolling NDA to the US FDA consisting of three data components. Submission began in the third quarter of 2003 and was completed by the fourth quarter of 2003. The first part of the application containing non-clinical information was submitted on 5 August 2003. The second part of the NDA containing information about efaproxiral's chemistry, manufacture and controls (CMC) was submitted in October 2003. Allos submitted its final component of the rolling NDA in December 2003. In February 2004, Allos announced that the FDA had accepted the company's NDA under priority review status. The FDA granted efaproxiral orphan drug status in August 2004 as an adjunct to WBRT for the treatment of brain metastases among breast cancer patients. Efaproxiral also received fast-track status in November 2000 for the same indication in the US. In February 2004, Allos initiated a phase III trial, called ENRICH (Enhancing Whole Brain Radiation Therapy In Patients with Breast Cancer and Hypoxic Brain Metastases) to investigate efaproxiral as an adjunct to WBRT for the treatment of brain metastases. Median survival time is the primary endpoint of the study. The National Breast Cancer Coalition (NBCC) is collaborating with the company to support trial enrolment and to gain additional insight about ways to improve radiation treatment in this patient population. The ENRICH trial protocol was approved by the FDA under a Special Protocol Assessment process; as part of the protocol, two interim analyses for safety and efficacy will be performed.This multicentre, randomised, open-label study has a target enrolment of approximately 360 patients at >100 medical centres across the US, Canada, Europe and South America. Allos announced in September 2004 that recruitment of clinical sites for the trial is ongoing across the US and Canada. Completion of trial enrolment in North America is anticipated in December 2005. Subsequently, Allos announced in January 2005 that recruitment into the ENRICH trial has commenced and is ongoing in Europe; enrolment at European sites is expected to conclude by the third quarter of 2006. Allos Therapeutics announced in June 2004 that it had filed an MAA with the EMEA for marketing of exaproxiral as an adjunct to WBRT for treatment of patients with brain metastases originating from breast cancer. The application is based on positive data from a pivotal phase III (REACH, RT-009) trial in this indication. The completed REACH trial investigated efaproxiral among patients with brain metastases undergoing WBRT. The trial was conducted at multiple sites in 11 countries, including the US, Canada, Europe and Australia. In August 2002 Allos completed the enrolment of 538 patients in the study. Initially only 408 patients were to be enrolled, but the company increased the size of the trial to conduct an appropriately powered subgroup analysis in patients with brain metastases from breast and NSCLC. The study was designed to demonstrate a 35% increase in median survival in the subgroup of patients compared with standard WBRT alone. The primary endpoint was survival. Allos began screening US patients for a phase III trial in NSCLC in early 2003. However, in May 2003, the company announced that as part of its revised operating plan it had suspended the screening of patients for this trial. The trial, which was known as ELITE (Enhanced Lung cancer treatment with Induction chemotherapy and Thoracic radiation and Efaproxiral), was comparing induction chemotherapy followed by thoracic radiation therapy with supplemental oxygen, with or without efaproxiral. The trial was enrolling patients with locally advanced, unresectable NSCLC. ELITE was planned to enrol up to 600 patients across North America and Western and Eastern Europe. Phase II trials in patients with inoperable NSCLC have been conducted in the US and Canada. Patient enrolment in one of these studies was completed in August 2000, with a total of 52 patients enrolled. This was an open-label, multicentre study of induction therapy with paclitaxel plus carboplatin followed by chest irradiation and efaproxiral in patients with locally advanced NSCLC. Positive results from this study were reported at the annual meeting of the European Society for Therapeutics Radiology and Oncology in September 2002. Efaproxiral has completed phase I trials as a treatment of surgical hypoxia in elective surgery patients receiving general anaesthesia. However, no recent development has been reported for these indications. In 1994, Allos signed an agreement with CIT for the exclusive worldwide rights to 17 US patents, a European patent covering the UK, France, Italy and Germany plus two pending patents in these territories, two issued patents in Japan, and a pending patent in Canada. These patents cover methods of allosterically modifying haemoglobin with efaproxiral and other compounds, the binding site of efaproxiral and therapy in certain indications including cancer, ischaemia and hypoxia. In addition to the licensed patents from CIT, Allos exclusively owns two patent families with pending applications directed to a formulation of efaproxiral and to methods of its use in BLOD MRI (blood oxygenation level-dependent magnetic resonance imaging) applications. These patents are pending in the US, Canada and Europe, and include an international patent application. In a May 2002 interview with the Wall Street Transcript, the CEO of Allos estimated the overall market for radiation therapy to be approximately 750 000 patients/year. Of this, brain metastases, NSCLC and glioblastoma therapy accounts for about 170 000, 140 000 and 6000 patients, respectively. Allos intend to use a speciality sales force to market efaproxiral directly to radiation therapists in North America. To penetrate the non-oncology market in the US, the company will seek partnership with one or more pharmaceutical companies with direct sales forces and with established distribution systems. Allos is also hoping to secure an oncology marketing partner for non-North American territories. At the time, the company had been issued 21 patents in the US, Canada, Europe and Japan.
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PMID:Efaproxiral: GSJ 61, JP 4, KDD 86, RS 4, RSR 13. 1586 22

Radiosensitizers represent an enticing concept in tumor therapy. As ionizing radiation affects both neoplastic and normal tissues, its effects are generally non-specific. The aim of applying a radiosensitizing agent is to achieve a maximum effect on tumor tissue, while minimizing the damage to normal tissues. A variety of parameters such as the oxygen supply and the state in the cell cycle, need to be taken into account when evaluating a potential radiosensitizer. Most of the previously known radiosensitizers are neither selective nor tumor specific. In this article, we review the properties and radiosensitizing potential of Photofrin II. Photofrin II is well-known as a photosensitizing agent in photodynamic therapy. In recent years, a radiosensitizing potential of the substance has been demonstrated, specifically increasing the sensitivity of solid tumor tissues, especially of radio-resistant, hypoxic tumor cells, to radiation. This radiosensitizing effect has been demonstrated both by in vitro studies and by animal experiments. Several studies with tissue cultures have demonstrated a radiosensitizing effect of Photofrin II in glioblastoma (U-373MG) and bladder cancer cell lines (RT-4). No effect was noted in colon carcinoma cell lines (HT-29). Unpublished data of additional cell lines will be mentioned in the review. Animal experiments with Lewis sarcoma and with bladder cancer have moreover demonstrated an in vivo effect of Photofrin II as a radiosensitizer. The mechanism of this radiosensitizing effect is not completely understood. In vitro data, however, support the hypothesis that the radiosensitizing action involves OH-radicals in addition to a potential impairment of repair mechanisms after sublethal damage of ionizing radiation. Moreover, early results of a phase I trial are available and document the potential feasibility of the application of Phototofrin II as a radiosensitizing agent in clinical practice.
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PMID:The Application of Photofrin II as a sensitizing agent for ionizing radiation--a new approach in tumor therapy? 1589 32

A prominent feature of glioblastoma is its resistance to death from Fas pathway activation. In this study, we explored the modulation of Fas-induced glioblastoma death with chemotherapeutic agents. Camptothecin significantly increased the glioblastoma cell death response to Fas receptor activation regardless of p53 status. Sublethal concentrations of camptothecin reduced the IC50 of agonistic anti-Fas antibody (CH-11) 10-fold, from 500 to 50 ng/mL, in human U87 glioblastoma cells (p53 wild-type). Cell viability in response to camptothecin, CH-11 alone, and the combination of camptothecin + CH-11 was found to be 84%, 85%, and 47% (P < 0.001), respectively. A similar pattern of relative cytotoxicity was found in U373 cells (p53 mutant). We further examined the pathways and mechanisms involved in this apparent synergistic cytotoxic response. Cell death was found to be predominantly apoptotic involving both extrinsic and intrinsic pathways as evidenced by annexin V staining, cleavage of caspases (3, 8, and 9), increased caspase activities, Smac release, and cytoprotection by caspase inhibitors. Expression of Fas-associated death domain, and not Fas, Fas ligand, or caspase proteins, increased following cell treatment with camptothecin + CH-11. Camptothecin treatment enhanced c-jun-NH2-kinase activation in response to CH-11, but inhibition of c-jun-NH2-kinase did not prevent cell death induced by the combination treatment. Reactive oxygen species, especially H2O2, were elevated following camptothecin treatment; and H2O2 enhanced cell death induced by CH-11. The antioxidants glutathione and N-acetyl-cysteine prevented cell death induced by camptothecin + CH-11. These findings show that camptothecin synergizes with Fas activation to induce glioblastoma apoptosis via a mechanism involving reactive oxygen species and oxidative stress pathways.
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PMID:Sensitization of glioma cells to Fas-dependent apoptosis by chemotherapy-induced oxidative stress. 1595 70

Reactive nitrogen and oxygen species (O2*-, H2O2, NO* and ONOO-) have been strongly implicated in the pathophysiology of neurodegenerative and mitochondrial diseases. In the present study, we examined the effects of nitrosative and/or nitrative stress generated by DETA-NO {(Z)-1-[2-aminoethyl-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate}, SIN-1 (3-morpholinosydnonimine hydrochloride) and SNP (sodium nitroprusside) on U87MG glioblastoma cybrids carrying wt (wild-type) and mutant [A3243G (Ala3243-->Gly)] mtDNA (mitochondrial genome) from a patient suffering from MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). The mutant cybrids had reduced activity of cytochrome c oxidase, significantly lower ATP level and decreased mitochondrial membrane potential. However, endogenous levels of reactive oxygen species were very similar in all cybrids regardless of whether they carried the mtDNA defects or not. Furthermore, the cybrids were insensitive to the nitrosative and/or nitrative stress produced by either DETA-NO or SIN-1 alone. Cytotoxicity, however, was observed in response to SNP treatment and a combination of SIN-1 and glucose-deprivation. The mutant cybrids were significantly more sensitive to these insults compared with the wt controls. Ultrastructural examination of dying cells revealed several characteristic features of autophagic cell death. We concluded that nitrosative and/or nitrative stress alone were insufficient to trigger cytotoxicity in these cells, but cell death was observed with a combination of metabolic and nitrative stress. The vulnerability of the cybrids to these types of injury correlated with the cellular energy status, which were compromised by the MELAS mutation.
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PMID:Effects of nitric oxide donors on cybrids harbouring the mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) A3243G mitochondrial DNA mutation. 1596 53

A 67-year-old man with glioblastoma was scheduled for craniotomy. Before anesthesia induction, asymptomatic bradycardia (40 beats x min(-1)) occurred, and was resistant to atropine 0.4 mg. The surgery was postponed. He was diagnosed as sick sinus syndrome (sinus arrest). He received implantation of a temporary cardiac pacemaker on the day before the rescheduled surgery. Anesthesia was induced with thiopental 400 mg, fentanyl 200 microg, vecuronium 10 mg and isoflurane 5%, and maintained with isoflurane 1-2% in oxygen 3 l x min(-1) and air 3 l x min(-1). Pacing mode was set to fixed rate asynchronous pacing in the ventricle with a rate of 50 beats x min(-1) after anesthesia induction. Surgery was completed in 8 hours and 45 minutes without any complications. The pacing wire was removed the next day. For patients with sick sinus syndrome, implantation of the pacemaker is indicated in case of bradycardia-tachycardia syndrome or with any clinical symptoms. However, a pacemaker should be implanted before general anesthesia even in a patient with no clinical symptoms because of cardiovascular instability induced by anesthesia.
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PMID:[General anesthesia for a patient with asymptomatic sick sinus syndrome]. 1610 50

Hypoxia inducible factors (HIF) are transcription factors regulating expression of several genes related to oxygen homeostasis in response to hypoxic stress. Although HIF1-alpha and platelet derived growth factor-B (PDGF-B) are expressed in glioma tissue and closely related to tumor angiogenesis mediating vascular endothelial growth factor (VEGF) activity, their direct relationship has not yet been clarified. The aim of this study is to investigate whether HIF1-alpha regulates PDGF-B expression. The human glioblastoma cell lines, U87MG, U251MG, and A172, were exposed to 1-21% oxygen for 24 h. PDGF-B mRNA expression were quantitatively analyzed by real time RT-PCR, their intracellular protein levels were determined by computerized image analysis supported by flow cytometry to detect intracellular PDGF-B, and the concentration of secreted PDGF-B protein was assayed by ELIA. We also assayed following transfection of the cells with short interference RNA (siRNA) targeting HIF1-alpha mRNA. Relative PDGF-B mRNA and secretion of PDGF-B protein were significantly elevated at 1% oxygen. Following transfection of HIF1-alpha siRNA at 1% oxygen, PDGF-B expression was significantly suppressed at mRNA level. Our findings indicated that HIF1-alpha up-regulated expression of PDGF-B in human glioblastoma cells and showed the feasibility of siRNA technology in glioblastoma cell lines.
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PMID:Hypoxia inducible factor 1-alpha regulates of platelet derived growth factor-B in human glioblastoma cells. 1613 72

Arsenic trioxide (As(2)O(3)) is effective against acute promyelocytic leukemia and has potential as a novel treatment against malignant solid tumors. As(2)O(3) induces differentiation and inhibits growth. It also causes mitochondrial damage mediated by the production of reactive oxygen species (ROS) and the dissipation of mitochondrial transmembrane potential (DeltaPsi(m)), leading to apoptosis. Mitochondria might be the key target of antitumor activity by As(2)O(3); however, its mechanisms have not been completely elucidated. Using two human glioblastoma cell lines, A172 and T98G, we found that As(2)O(3) induced apoptosis in A172 cells but not in T98G cells. As(2)O(3)-induced ROS production was observed in both cell lines; however, the dissipation of DeltaPsi(m), Bax oligomerization and caspase activation occurred only in As(2)O(3)-sensitive A172 cells. To determine the mechanisms of As(2)O(3)-induced apoptosis after ROS generation, we examined the change of mitochondrial morphology. As we reported previously, mitochondrial aggregation occurs before cytochrome c release during apoptosis, thus playing a role in cell death progression. We observed mitochondrial aggregation in As(2)O(3)-sensitive A172 cells but not in T98G cells treated with As(2)O(3). Using laser scanning cytometry, we quantitatively confirmed the results, which indicate that mitochondrial aggregation plays an important role in regulating sensitivity to As(2)O(3)-induced apoptosis. We propose a sequential process involving ROS generation, mitochondrial aggregation, Bax oligomerization and DeltaPsi(m) dissipation, and caspase activation during As(2)O(3)-induced apoptosis.
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PMID:Involvement of mitochondrial aggregation in arsenic trioxide (As2O3)-induced apoptosis in human glioblastoma cells. 1627 Oct 77

The naturally occurring photosensitizer, hypericin, with its high quantum yield of singlet oxygen photogeneration was studied for its ability to differentiate between glioblastoma cells and fetal rat neurons using fluorescence microscopy. Eight human glioma cell lines and twelve primary human glioma cell cultures were compared to human astrocytes and cerebellar granule neurons after incubation with 20 microM hypericin for 5-120 min. Photobleaching effects have been studied by exposing the cell lines to 100 msec of excitation light (510-550 wavelength). Mainly, perinuclear hypericin staining was detected. Neurons can be differentiated from glioblastoma cell lines and astrocytes by a lower fluorescence intensity (Tukey-Kramer HSD test, p < 0.0001). Therefore, hypericin seems to be a promising substance for the photodynamic therapy of malignant brain tumors.
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PMID:Hypericin: a promising fluorescence marker for differentiating between glioblastoma and neurons in vitro. 1627 10

Hypoxia is a crucial factor in tumor aggressiveness and resistance to treatment, particularly in glioma. Our previous results have shown that inhibiting the small GTPase RhoB increased oxygenation of U87 human glioblastoma xenografts, in part, by regulating angiogenesis. We investigated here whether RhoB might also control a signaling pathway that would permit glioma cells to adapt to hypoxia. We first showed that silencing RhoB with siRNA induced degradation and inhibition of the transcriptional activity of the hypoxia-inducible factor by the proteasome in U87 hypoxic cells. This RhoB-dependent degradation of hypoxia-inducible factor-1alpha in hypoxic conditions was mediated by the Akt/glycogen synthase kinase-3beta pathway. While investigating how hypoxia could activate this signaling pathway, using the GST-Rhotekin RBD pulldown assay, we showed the early activation of RhoB by reactive oxygen species under hypoxic conditions and, subsequently, its participation in the ensuing cellular adaptation to hypoxia. Overall, therefore, our results have not only highlighted a new signaling pathway for hypoxia controlled by the small GTPase RhoB, but they also strongly implicate RhoB as a potentially important therapeutic target for decreasing tumor hypoxia.
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PMID:Activation of RhoB by hypoxia controls hypoxia-inducible factor-1alpha stabilization through glycogen synthase kinase-3 in U87 glioblastoma cells. 1639 64


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