Overall Survival Of Glioblastoma Multiforme Patients Research Articles

O9.10 * ANTI-EPILEPTIC TREATMENT IN GLIOMA, A NORWEGIAN POPULATION-BASED STUDY

INTRODUCTION: Symptomatic epilepsy in glioma is traditionally perceived as difficult to treat and refractory to monotherapy. Older AEDs that induce or inhibit CytP450 enzyme systems (enzyme-inducing AED= EIAED) have previously been preferred. There is an increasing focus on the risk of interaction with other drugs with hepatic metabolism. We wanted to study whether newer AEDs with little or no enzyme effect (non-EIAED) are favored in the current treatment of epilepsy in glioma. MATERIALS AND METHODS: We identified all glioma patients with epilepsy in Norway by linking the Cancer Registry of Norway (CRN) and the Norwegian Prescription Database (NorPD). CRN has since 1952 registered information on all neoplasms diagnosed in Norway, and reporting is mandatory by law for clinicians and pathologists. NorPD was founded in 2004 by the Norwegian Institute of Public Health, and includes information on all prescriptions dispensed from all Norwegian pharmacies. We included all patients with glioma grade II-IV who were registered in NorPD. Epilepsy was defined as being registered as taking AEDs under a relevant epileptic diagnostic code. RESULTS: In 2004-2010, CRN registered 2583 patients with glioma grade II-IV, 1477 men and 1106 women. In low grade glioma, 65% had epilepsy and in high grade glioma, 47% had epilepsy. Low grade gliomas with epilepsy were localized in the frontal lobe in 46%. High grade gliomas with epilepsy were localized in the frontal lobe in 28% and the temporal lobe in 27%. In monotherapy or with other AEDs, carbamazepine was used by 34% and valproate by 36% of the 1104 patients with glioma and epilepsy. Patients aged 20-49 years with astrocytoma, and 40-79 years with glioblastoma multiforme (GBM), used non-EIAEDs more frequently than EIAEDs. Levetiracetam was the preferred AED, used by 39% of the 1104 patients. DISCUSSION: The non-EIAED levetiracetam was the most frequently used AED in glioma patients, especially in GBM. GBM patients often have overall survival <1 year and side effects of AEDs are particularly important. Levetiracetam can give cognitive side effects as mood changes or depression, reducing quality of life. Some studies have indicated an anti-tumor effect of valproate and levetiracetam. In this study, we are investigating whether the usage of different AEDs affect overall survival in GBM patients. CONCLUSION: In the Norwegian population 2004-2010, 65% of patients with low grade gliomas and 47% of patients with high grade gliomas had epilepsy. Levetiracetam was the most frequently used AED, especially in GBM. We further investigate the influence of exposure to the separate AEDs on overall survival in the GBM patients, and these results are to be presented.

MicroRNA expression signatures and their correlation with clinicopathological features in glioblastoma multiforme.

The increasing interest in identifying molecular biomarkers to determine patient prognosis in glioblastoma multiforme (GBM) has resulted in several microRNA (miRNA)-based signatures able to predict progression-free and overall survival. However, the coherency between these signatures is small, and correlations to clinicopathological features other than survival are seldom seen. The aim of this study was to identify any significant relationship between miRNA signatures and clinicopathological data by combining pathological features with miRNA and mRNA analysis in fourteen GBM patients. In total, 161 miRNAs were shown to cluster the GBM tumor samples into long- and short-term-surviving patients. Many of these miRNAs were associated with differential expression in GBM, including a number of miRNAs shown to confer risk or protection with respect to clinical outcome and to modulate the mesenchymal mode of migration and invasion. An inverse relationship between miR-125b and nestin expression was identified and correlated with overall survival in GBM patients, eloquently illustrating how clinicopathological findings and molecular profiling may be a relevant combination to predict patient outcome. The intriguing finding that many of the differentially expressed miRNAs contained exosome-packaging motifs in their mature sequences suggests that we must expand our view to encompass the complex intercellular communication in order to identify molecular prognostic biomarkers and to increase our knowledge in the field of GBM pathogenesis.

Pharmacological inhibition of poly(ADP-ribose) polymerase-1 modulates resistance of human glioblastoma stem cells to temozolomide

BackgroundChemoresistance of glioblastoma multiforme (GBM) has been attributed to the presence within the tumor of cancer stem cells (GSCs). The standard therapy for GBM consists of surgery followed by radiotherapy and the chemotherapeutic agent temozolomide (TMZ). However, TMZ efficacy is limited by O6-methylguanine-DNA-methyltransferase (MGMT) and Mismatch Repair (MMR) functions. Strategies to counteract TMZ resistance include its combination with poly(ADP-ribose) polymerase inhibitors (PARPi), which hamper the repair of N-methylpurines. PARPi are also investigated as monotherapy for tumors with deficiency of homologous recombination (HR). We have investigated whether PARPi may restore GSC sensitivity to TMZ or may be effective as monotherapy.MethodsTen human GSC lines were assayed for MMR proteins, MGMT and PARP-1 expression/activity, MGMT promoter methylation and sensitivity to TMZ or PARPi, alone and in combination. Since PTEN defects are frequently detected in GBM and may cause HR dysfunction, PTEN expression was also analyzed. The statistical analysis of the differences in drug sensitivity among the cell lines was performed using the ANOVA and Bonferroni’s post-test or the non-parametric Kruskal-Wallis analysis and Dunn’s post-test for multiple comparisons. Synergism between TMZ and PARPi was analyzed by the median-effect method of Chou and Talalay. Correlation analyses were done using the Spearman’s rank test.ResultsAll GSCs were MMR-proficient and resistance to TMZ was mainly associated with high MGMT activity or low proliferation rate. MGMT promoter hypermethylation of GSCs correlated both with low MGMT activity/expression (Spearman’s test, P = 0.004 and P = 0.01) and with longer overall survival of GBM patients (P = 0.02). Sensitivity of each GSC line to PARPi as single agent did not correlate with PARP-1 or PTEN expression. Notably, PARPi and TMZ combination exerted synergistic antitumor effects in eight out of ten GSC lines and the TMZ dose reduction achieved significantly correlated with the sensitivity of each cell line to PARPi as single agent (P = 0.01).ConclusionsThe combination of TMZ with PARPi may represent a valuable strategy to reverse GSC chemoresistance.

MiR-106a is an independent prognostic marker in patients with glioblastoma

Very little is known regarding correlation of micro RNA (miR)-106a with clinical outcomes of patients with glioblastoma multiforme (GBM). This study determined whether miR-106a could be used as an independent prognostic biomarker in those patients. A total of 156 GBM patients were divided into 2 cohorts. In the first cohort, matched fresh frozen and formalin-fixed paraffin-embedded (FFPE) samples were collected from 24 GBM patients, while in the second cohort, only FFPE samples were collected from 132 GBM patients. MiR-106a expression levels were examined by quantitative real-time PCR in the 2 cohorts and further validated by in situ hybridization assay in the second cohort. The correlation between miR-106a expression levels and overall survival was evaluated in the second cohort of 114 GBM patients available for follow-up by a log-rank test and a multivariate Cox proportional hazards model. Our data showed a very good correlation of miR-106a or U6 expression between fresh frozen and FFPE GBM specimens, with Pearson's correlation coefficients of 0.849 and 0.823, respectively (P < .001). Their expression levels in archival FFPE samples were quite stable for at least 7 years when stored at room temperature. Multivariate analysis revealed that the expression level of miR-106a was an independent and significant predictor of overall survival in GBM patients (P = .011). MiR-106a expression was relatively abundant and stable in a large cohort of archival FFPE GBM specimens and could be used as an independent prognostic biomarker in those patients. Thus, miR-106a can be used to predict prognosis and treatment response in individual GBM patients.

The prognostic value of MGMT promoter methylation in Glioblastoma multiforme: a meta-analysis

The prognostic significance of O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation on Glioblastoma multiforme (GBM) remains controversial. A meta-analysis of published studies investigating the effects of MGMT promoter methylation on both progression-free survival (PFS) and overall survival (OS) among GBM patients was performed. A total of 2,986 patients from 30 studies were included in the meta-analysis. In all, the frequency of MGMT promoter methylation was 44.27 %. Five studies undertook univariate analyses and nine undertook multivariate analyses of MGMT promoter methylation on PFS. The pooled hazard ratio (HR) estimate for PFS was 0.72 (95 % CI 0.55-0.95) by univariate analysis and 0.51 (95 % CI 0.38-0.69) by multivariate analysis. The effect of MGMT promoter methylation on OS was evaluated in 15 studies by univariate analysis and 14 studies by multivariate analysis. The combined HR was 0.67 (95 % CI 0.58-0.78) and 0.49 (95 % CI 0.38-0.64), respectively. For GBM patients treated with Alkylating agent, the meta-risk remained highly significant by both univariate (HR = 0.58; 95 % CI 0.42-0.79) and multivariate analysis (HR = 0.42; 95 % CI 0.29-0.60). This study showed that MGMT promoter methylation was associated with better PFS and OS in patients with GBM regardless of therapeutic intervention, and associated with longer OS in GBM patients treated with alkylating agents.

Analysis of CD137L and IL-17 Expression in Tumor Tissue as Prognostic Indicators for Gliblastoma

Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by genetic instability and unpredictable clinical behavior. GBM is marked by an extremely poor prognosis with median overall survival of 12~14 months. In this study, we detected the CD137L-expressing cells and IL-17-expressing cells in tumor tissues resected from patients with GBM. Expression of CD137L and IL-17 were assessed by immunohistochemistry, and the prognostic value of CD137L and IL-17 expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. Immunohistochemical detection showed that positive cells of CD137L and IL-17 in glioblastoma tissue samples were 46.3% (19/ 41) and 73.2% (30/41) respectively. Expression of CD137L was not correlated with overall survival of GBM patients (P=0.594), while significantly longer survival rate was seen in patients with high expression of IL-17, compared to those with low expression of IL-17 (P=0.007). In addition, we also found that IL-17 expression was significantly correlated with Progression-free survival (PFS) (P=0.016) and death rate (P=0.01). Furthermore, multivariate Cox proportional hazard analyses revealed that IL-17 (P=0.018) and PFS (P=0.028) were independent factors affecting the overall survival probability. Kaplan-Meier analysis showed that PFS of high expression of IL-17 group were significantly longer (P=0.004) than low expression group with GBM. It is concluded that high levels of IL-17 expression in the tumor tissues may be a good prognostic marker for patients with GBM.

Prognostic impact of the expression/phosphorylation of the BH3-only proteins of the BCL-2 family in glioblastoma multiforme

Apoptosis has a crucial role in anti-cancer treatment. The proteins of the BCL-2 family are core members of the apoptotic program. Thus, we postulated that alterations in the expression of BCL-2 protein family, and in particular in that of the Bcl-2 homology domain 3 (BH3)-only proteins (which can neutralized anti-apoptotic proteins or activate pro-apoptotic proteins) could account for differences in the overall survival (OS) of patients. To test this hypothesis, we analyzed the expression of 15 members of the BCL-2 protein family (Bax, Bak, Bok, Bcl-2, Bcl-xl, Bcl-w, Mcl-1, Bad, Bid, Bim, Bik, Bmf, Hrk, Noxa and Puma) in glioblastoma multiforme (GBM) tumors, the most frequent brain tumor in adults. We found that none of the individual expression of these proteins is associated with a significant variation in OS of the patients. However, when all BH3 proteins were pooled to determine a BH3score, this score was significantly correlated with OS of GBM patients. We also noted that patients with a have high level of phospho-Bad and phospho-Bim displayed a lower OS. Thus, BH3 scoring/profiling could be used as an independent prognostic factor in GBM when globally analyzed.

MiR-34a functions as a tumor suppressor modulating EGFR in glioblastoma multiforme

Chromosome 1p36.23 is frequently deleted in glioblastoma multiforme (GBM). miR-34a localizes in this region. Our experiments found that miR-34a was often deleted and epidermal growth factor receptor (EGFR) was frequently amplified in genomic DNA of 55 GBMs using single-nucleotide polymorphism DNA microarray. Notably, we found that the mean survival time was significantly shortened for patients whose GBMs had both EGFR amplification and miR-34a deletion. Expression of miR-34a was significantly lower in GBM samples compared with normal brain tissue. Forced expression of miR-34a in GBM cells decreased their ability to migrate and profoundly decreased their levels of cyclin-A1, -B1, -D1, and -D3, as well as cyclin-dependent kinase and increased expression of cyclin kinase inhibitor proteins (p21, p27). Also, human GBM cells (U251) stable overexpressing mir-34a formed smaller tumors when growing as xenografts in immunodeficient mice compared with wild-type U251 GBM cells. Furthermore, the protein expression of EGFR decreased in the cells with forced overexpression of miR-34a. Additional studies showed that mir-34a targeted Yin Yang-1 (YY1) and YY1 is a transcription factor that can stimulate the expression of EGFR. Thus, our data suggest that miR-34a acts as a tumor suppressor by inhibiting growth of GBM cells in vitro and in vivo associated with moderating the expression of cell-cycle proteins and EGFR. Moreover, we discovered for the first time that both deletion of miR-34a and amplification of EGFR were associated with significantly decreased overall survival of GBM patients.

The autophagy-associated factors DRAM1 and p62 regulate cell migration and invasion in glioblastoma stem cells

The aggressiveness of glioblastoma multiforme (GBM) is defined by local invasion and resistance to therapy. Within established GBM, a subpopulation of tumor-initiating cells with stem-like properties (GBM stem cells, GSCs) is believed to underlie resistance to therapy. The metabolic pathway autophagy has been implicated in the regulation of survival in GBM. However, the status of autophagy in GBM and its role in the cancer stem cell fraction is currently unclear. We found that a number of autophagy regulators are highly expressed in GBM tumors carrying a mesenchymal signature, which defines aggressiveness and invasion, and are associated with components of the MAPK pathway. This autophagy signature included the autophagy-associated genes DRAM1 and SQSTM1, which encode a key regulator of selective autophagy, p62. High levels of DRAM1 were associated with shorter overall survival in GBM patients. In GSCs, DRAM1 and SQSTM1 expression correlated with activation of MAPK and expression of the mesenchymal marker c-MET. DRAM1 knockdown decreased p62 localization to autophagosomes and its autophagy-mediated degradation, thus suggesting a role for DRAM1 in p62-mediated autophagy. In contrast, autophagy induced by starvation or inhibition of mTOR/PI-3K was not affected by either DRAM1 or p62 downregulation. Functionally, DRAM1 and p62 regulate cell motility and invasion in GSCs. This was associated with alterations of energy metabolism, in particular reduced ATP and lactate levels. Taken together, these findings shed new light on the role of autophagy in GBM and reveal a novel function of the autophagy regulators DRAM1 and p62 in control of migration/invasion in cancer stem cells.

Hexokinase 2 is a key mediator of aerobic glycolysis and promotes tumor growth in human glioblastoma multiforme

Proliferating embryonic and cancer cells preferentially use aerobic glycolysis to support growth, a metabolic alteration commonly referred to as the "Warburg effect." Here, we show that the glycolytic enzyme hexokinase 2 (HK2) is crucial for the Warburg effect in human glioblastoma multiforme (GBM), the most common malignant brain tumor. In contrast to normal brain and low-grade gliomas, which express predominantly HK1, GBMs show increased HK2 expression. HK2 expression correlates with worse overall survival of GBM patients. Depletion of HK2, but neither HK1 nor pyruvate kinase M2, in GBM cells restored oxidative glucose metabolism and increased sensitivity to cell death inducers such as radiation and temozolomide. Intracranial xenografts of HK2-depleted GBM cells showed decreased proliferation and angiogenesis, but increased invasion, as well as diminished expression of hypoxia inducible factor 1α and vascular endothelial growth factor. In contrast, exogenous HK2 expression in GBM cells led to increased proliferation, therapeutic resistance, and intracranial growth. Growth was dependent on both glucose phosphorylation and mitochondrial translocation mediated by AKT signaling, which is often aberrantly activated in GBMs. Collectively, these findings suggest that therapeutic strategies to modulate the Warburg effect, such as targeting of HK2, may interfere with growth and therapeutic sensitivity of some GBMs.

Adjuvant Gamma Knife Stereotactic Radiosurgery at the Time of Tumor Progression Potentially Improves Survival for Patients with Glioblastoma Multiforme

Gamma knife stereotactic radiosurgery (GK-SRS) is a safe and noninvasive treatment used as adjuvant therapy for patients with glioblastoma multiforme (GBM). Several studies have yielded conflicting results in the effectiveness of radiosurgery in GBM. This study is a retrospective review of our institutional experience with GK-SRS adjuvant therapy in the treatment of GBM. From October 1998 to January 2003, 51 consecutive patients were treated with GK-SRS as an "upfront" adjuvant therapy after surgery or at the time of tumor progression at Northwestern Memorial Hospital. Survival analysis was performed using the Kaplan-Meier actuarial method. Univariate and multivariate analyses of patient characteristics and treatment variables were performed. Treatment with adjuvant GK-SRS yielded a median overall survival of 14.3 months for our cohort. Survival rate of the cohort was 68% at 12 months, 30% at 24 months, and 24% at 36 months. Karnofsky performance score greater than 90 and adjuvant chemotherapy were associated with increased survival on multivariate analysis. Adjuvant GK-SRS performed at tumor progression seems to increase median survival to 16.7 months compared with 10 months when performed after the time of initial tumor resection. Median survival rates by recursive partitioning analysis class breakdown in our cohort are greater than those predicted by other studies. GK-SRS is a relatively safe and noninvasive procedure that conferred an improvement in overall survival of GBM patients in our retrospective study. Particularly, GK-SRS may improve overall survival when performed at the time of tumor progression.