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)

Recently completed trials suggest the addition of nitrosourea-based chemotherapy to radiotherapy increases the progression-free but not overall survival of grade II and III gliomas. Temozolomide has proven benefit in grade II/III gliomas progressive following standard therapy and when added to radiation for glioblastoma. Newly launched and planned phase III trials will explore whether the addition of temozolomide to radiotherapy improves overall survival in grade II/III as well as the prognostic and predictive value of 1p/19q analyses and MGMT promotor methylation status. Additionally, they will measure cognition and quality of life to determine if improvements in time to progression translate into better functional status and patient satisfaction.
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PMID:Temozolomide and radiation in low-grade and anaplastic gliomas: temoradiation. 1795 45

Chemotherapy has become a third major treatment option for patients with brain tumors, in addition to surgery and radiotherapy. The role of chemotherapy in the treatment of gliomas is no longer limited to recurrent disease. Temozolomide has become the standard of care in newly diagnosed glioblastoma. Several ongoing trials seek to define the role of chemotherapy in the primary care of other gliomas. Some of these studies are no longer only based on histological diagnoses, but take into consideration molecular markers such as MGMT promoter methylation and loss of genetic material on chromosomal arms 1p and 19q. Outside such clinical trials chemotherapy is used in addition to radiotherapy, e.g., in anaplastic astrocytoma, medulloblastoma or germ cell tumors, or as an alternative to radiotherapy, e.g., in anaplastic oligodendroglial tumors or low-grade gliomas. In contrast, there is no established role for chemotherapy in other tumors such as ependymomas, meningiomas or neurinomas. Primary cerebral lymphomas are probably the only brain tumors which can be cured by chemotherapy alone and only by chemotherapy. The chemotherapy of brain metastases follows the recommendations for the respective primary tumors. Further, strategies of combined radiochemotherapy using mainly temozolomide or topotecan are currently explored. Leptomeningeal metastases are treated by radiotherapy or systemic or intrathecal chemotherapy depending on their pattern of growth.
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PMID:[Chemotherapy for brain tumors in adult patients]. 1825 73

Malignant gliomas of which glioblastomas represent the ultimate grade of malignancy are characterized by dismal prognoses because malignant glioma cells present both important proliferation and neoangiogenesis processes and can actively migrate through the narrow extra-cellular spaces in the brain, often travelling relatively long distances, making them elusive targets for effective surgical management. Invasive malignant glioma cells show a decrease in their proliferation rates and a relative resistance to apoptosis (type I programmed cell death) as compared to the highly cellular centre of the tumour, and this may contribute to their resistance to conventional proapoptotic chemotherapy and radiotherapy. The multidisciplinary up to date treatment for glioblastoma patients combined maximal surgical removal of the tumor with postoperative radiotherapy and concomitant chemotherapy with temozolomide. Temozolomide is a proautophagic (type II programmed cell death) drug and can thus circumvent part of the glioblastoma resistance to apoptosis. Another way to potentially overcome apoptosis resistance is to decrease the migration of malignant glioma cells in the brain, which then should restore a level of sensitivity to proapoptotic drugs. The Na(+)/K(+)-ATPase or sodium pump is an ion transporter which in addition to exchanging cations, is also the ligand for cardenolides and is directly involved in the migration of cancer cells in general and of glioma cells in particular. We have shown that the alpha1 subunit of the sodium pump is highly expressed in glioma cells compared to normal brain tissues and we are the first to propose the alpha1 subunit of the sodium pump as a new target in the context of malignant glioma treatment. Using a novel cardenolide with unique structural features, which markedly inhibits sodium pump activity and binds to the alpha1 subunit, we have shown marked anti-proliferative and anti-migratory effects on human glioblastoma cells (and other cancer cell types). We have characterized at least partially the anti-cancer mechanism of action of the novel cardenolide. It is a ligand of the alpha1 subunit of the pump which impairs the proliferation and migration of glioblastoma cells by disorganizing the actin cytoskeleton and inducing severe autophagic process in glioblastoma cells. Collectively, these data suggests that the novel cardenolide is an attractive candidate for preclinical and clinical development, at least in the area of glioblastoma. This compound should reach phase I clinical trials in the summer of 2008.
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PMID:[The sodium pump could constitute a new target to combat glioblastomas]. 1839 Apr 7

Acetazolomide (ACZ) and dexamethasone (DXM) alleviate vasogenic edema and inflammation in glioblastoma patients. Temozolomide (TMZ) is used for treating glioblastoma. We compared modulatory effects of ACZ and DXM on TMZ mediated apoptosis in human glioblastoma T98G and U87MG cells. Cells were treated with drug(s) for 6 h and then left in drug-free medium for 48 h. Although ACZ or DXM alone did not induce apoptosis, TMZ alone induced significant amount of apoptosis. Interestingly, ACZ pretreatment enhanced apoptosis while DXM pretreatment decreased apoptosis. These results suggest that combination chemotherapy with ACZ and TMZ may control inflammation and enhance apoptosis in glioblastoma.
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PMID:Modulatory effects of acetazolomide and dexamethasone on temozolomide-mediated apoptosis in human glioblastoma T98G and U87MG cells. 1844 55

A phase I trial was conducted to determine the maximum tolerated dose (MTD) of temozolomide given in combination with lomustine in newly diagnosed pediatric patients with high-grade gliomas. Response was assessed following two courses of therapy at the MTD. Temozolomide was administered to cohorts of patients at doses of 100, 125, 160, or 200 mg/m(2) on days 1-5, along with 90 mg/m(2) lomustine on day 1. Two courses of lomustine/temozolomide were given prior to radiation therapy (RT) and up to six courses were administered afterward. Thirty-two patients were enrolled. Dose-limiting myelosuppression was seen in two of three patients enrolled at the 200 mg/m(2) dose level. One of 14 patients in the expanded MTD cohort (160 mg/m(2)) experienced dose-limiting thrombocytopenia. After two courses at the MTD, one patient with a 5-mm enhancing nodule postoperatively had a complete response, one patient with a large residual temporal lobe glioblastoma had a partial response, and eight patients had stable disease. Several patients developed transient radiographic worsening after completing RT. Median 1- and 2-year overall survivals at the MTD were 60% +/- 13% and 40% +/- 13% with a median of 17.6 months. Thirteen of 20 patients (65%) who underwent MRI scans within 6 months prior to death developed metastatic disease. In conclusion, when administered with 90 mg/m(2) lomustine on day 1, the MTD of temozolomide is 160 mg/m(2)/day x 5. Radiographic changes following RT make determination of early tumor progression difficult. Metastatic disease is common prior to death.
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PMID:A phase I trial of temozolomide and lomustine in newly diagnosed high-grade gliomas of childhood. 1849 27

Meningiomas are usually cured by surgical resection. However, approximately 10% are characterized by more aggressive clinical behavior and higher risk of recurrence. Typically, recurrent meningiomas require further surgical resection followed, in some cases, by radiotherapy. To date, no chemotherapeutic agent has proven to be effective in either preventing or treating recurrence. The alkylating chemotherapeutic agent, Temozolomide (TMZ) has shown to increase overall survival in patients with glioblastoma (GBM) but its effectiveness for other types of brain tumor is less known. The clinical benefit of TMZ seems to be limited to those GBM tumors with promoter methylation of the MGMT gene. In this study, we assessed if a biologic rationale exists to support the use of TMZ as a treatment for meningiomas by assessing the MGMT promoter methylation status in these tumors using methylation specific PCR. We investigated the MGMT promoter methylation status in 36 tumors (32 newly diagnosed; 4 recurrent). Histologically, the majority were grade I. Patients were primarily female (64%) with a mean age of 52. None of the meningiomas in our series showed MGMT gene promoter methylation. Based on these data, we conclude that there is no biological rational to suggest that TMZ might have significant anti-meningioma activity.
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PMID:Methylation status of MGMT gene promoter in meningiomas. 1899 37

The present study aims to assess the feasibility and the effectiveness of a second-line Fotemustine chemotherapy in patients with recurrent Glioblastoma after standard primary treatment. Between 2005 and 2007, 50 patients with relapsed malignant glioma (median age=56.8 years; median KPS=90) underwent a second-line chemotherapy with Fotemustine. Selected patients were previously treated with a standard 60 Gy Radiotherapy course and Temozolomide Chemotherapy. Patients were stratified into classes according to the prognostic Recursive Partition Analysis. Endpoints of the study were Progression Free Survival at 6 months, duration of Objective Response and Stabilization, Overall Survival and toxicity. At analysis, 36 patients were dead and 14 were alive. Median follow-up from primary diagnosis was 26.6 months. The Efficacy control of the disease was 62%. PFS was 6.1 months; PFS-6 was 52% and median overall survival from primary diagnosis was 24.5 months, with few manageable haematological toxicities. Fotemustine was safe and effective as second-line chemotherapy in recurrent glioblastoma.
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PMID:A multi-institutional phase II study on second-line Fotemustine chemotherapy in recurrent glioblastoma. 1901 76

Temozolomide (TMZ) and carmustine (BCNU), cancer-drugs usually used in the treatment of gliomas, are DNA-methylating agents producing O6-methylguanine. It has been shown that 06-methylguanine triggers DNA mismatch repair and in turn induce apoptosis and senescence, respectively, over a 4 and 6 days period [Y. Hirose, M.S. Berger, R.O. Pieper, p53 effects both the duration of G2/M arrest and the fate of temozolomide-treated human glioblastoma cells, Cancer Res. 61 (2001) 1957-1963; W. Roos, M. Baumgartner, B. Kaina, Apoptosis triggered by DNA damage O6-methylguanine in human lymphocytes requires DNA replication and is mediated by p53 and Fas/CD95/Apo-1, Oncogene 23 (2004) 359-367]. Here we show that TMZ and BCNU have an earlier effect on nuclear organization and chromatin structure. In particular, we report that TMZ and BCNU induce clustering of pericentromeric heterochromatin regions and increase the amount of heterochromatic proteins MeCP2 and HP1alpha bound to chromatin. These drugs also decrease global levels of histone H3 acetylation and increase levels of histone H3 trimethylated on lysine 9 (H3-triMeK9). These events precede the senescence status. We conclude that TMZ and BCNU efficacy in glioma treatment may implicate a first event characterized by changes in heterochromatin organization and its silencing which is then followed by apoptosis and senescence.
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PMID:Temozolomide and carmustine cause large-scale heterochromatin reorganization in glioma cells. 1911 35

Temozolomide (TMZ) is an oral anticancer agent approved for the treatment of newly diagnosed glioblastoma in combination with radiotherapy. Moreover, TMZ has shown comparable efficacy with respect to dacarbazine, the reference drug for metastatic melanoma. Due to its favorable toxicity and pharmacokinetic profile, TMZ is under clinical investigation for brain metastasis from solid tumors and refractory leukemias. TMZ interacts with DNA generating a wide spectrum of methyl adducts mainly represented by N-methylpurines. However, its antitumor activity has been mainly attributed to O(6)-methylguanine, since tumor cell sensitivity inversely correlates with the levels of O(6)-alkylguanine DNA alkyltransferase and requires an intact mismatch repair system. Therefore, an increasing number of studies have been performed in order to identify patients who will benefit from TMZ treatment on the basis of their molecular/genetic profile. Unfortunately, resistance to the methylating agent occurs relatively often and strongly affects the rate and durability of the clinical response in cancer patients. Thus, different approaches have been developed to abrogate resistance or to increase the efficacy of TMZ and for many of them investigation is still underway. Herein, we provide an overview on the recent findings of preclinical and clinical studies on TMZ in combination with inhibitors of DNA repair, chemotherapeutic drugs with different mechanisms of action or radiotherapy, anti-angiogenic agents and other biological modulators.
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PMID:Recent approaches to improve the antitumor efficacy of temozolomide. 1914 75

Temozolomide (TMZ) is the standard of care for patients with newly diagnosed glioblastoma (GBM) as well as those with recurrent anaplastic glioma (AG) and GBM. It has become common practice to re-expose patients to TMZ who had been previously treated with TMZ, or to switch patients to alternative dosing regimens of TMZ when there are signs of relapse or progress on standard TMZ therapeutic regimens. To date, however, there is a scarcity of data on the efficacy of this therapeutic strategy, currently referred to as TMZ rechallenge. We have conducted a retrospective review of patients with recurrent glioma rechallenged with TMZ. Patients experiencing progressive disease (PD) during TMZ therapy who were rechallenged with alternative TMZ regimens and patients rechallenged after stable disease in a TMZ-free interval were evaluated separately. A total of 90 rechallenges were identified in 80 patients. The progression-free survival at 6 months (PFS-6) was 48% in patients with AG (12/25) and 27.7% in those with GBM (14/47). The PFS-6 was 16.7% in AG and 26.3% in GBM for patients switched during TMZ and 57.9 and 28.6% in patients rechallenged after a TMZ-free interval of at least 8 weeks. Relevant hematological toxicity (NCI-CTC grade 3-5) was observed in 22 of 90 rechallenges, and relevant non-hematological in ten of 90 rechallenges. Temozolomide was well tolerated and generated promising PFS-6 in patients who had previously failed TMZ, regardless if they progressed during TMZ treatment, or if they were rechallenged after a TMZ-free interval. These results suggest that the TMZ rechallenge strategy warrants further investigation in a prospective randomized trial.
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PMID:Rechallenge with temozolomide in patients with recurrent gliomas. 1924 Sep 62


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