The future of high-grade glioma: Where we are and where are we going

Interleukin-17 receptor D is a favorable biomarker of glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most frequent glioma in adults. The prognosis of GBM is very poor and new prognostic biomarkers are in urgent need to better select high-risk patients and guide the individual treatments.

METHODS

In our study, we compared the expression of interleukin-17 receptor D (IL17RD) between GBMs and normal tissues from TCGA database, and detected IL17RD mRNA in 17 fresh GBM pairs with qPCR. With immunohistochemistry, we investigated the expression of IL17RD in 156 GBM tissues and further evaluated its clinical significance. The associations between IL17RD and clinicopathological factors were assessed by Chi-square test. The prognostic significance of IL17RD was evaluated by univariate analysis with Kaplan-Meier method, and by multivariate analysis with Cox-regression Hazard model.

RESULTS

The TPMs and mRNAs of IL17RD in GBM were substantially lower than those in normal brain tissues. The rates of low or high expression of IL17RD accounted for 41.67% and 58.33% respectively. IL17RD was significantly associated with higher survival rates of GBM. The 3-year overall survival rates of patients with low and high IL17RD were 7.2% and 19.5% respectively. In the Cox-regression model, the IL17RD expression was defined as an independent prognostic biomarker of GBM. Patients with high IL17RD expression had a more favorable outcome than those with low IL17RD.

CONCLUSIONS

High IL17RD expression was an independent prognostic indicator of GBM, suggesting a more favorable prognosis. Our results suggested that IL17RD detection may help find the high-risk patients which may receive more severe surveillance and more individual treatments.

Markedly divergent effects of Ouabain on a Temozolomide-resistant (T98G) vs. a Temozolomide-sensitive (LN229) Glioblastoma cell line

BACKGROUND

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with poor prognosis. GMB are highly recurrent mainly because of radio- and chemoresistance. Radiotherapy with Temozolomide (TMZ) is until today the golden standard adjuvant therapy, however, the optimal treatment of recurrent glioblastoma remains controversial. Ouabain belongs to the Cardiotonic Steroids (CTS) the natural ligands of the Na/K-ATPase (NKA). It is established that the NKA represents a signal transducer with either stimulating or inhibiting cell growth, apoptosis, migration and angiogenesis. Over the last decade evidence grew that CTS have anti-tumor properties especially in GBM.

AIM

Proceeding from recent studies we wanted to further demonstrate a divergent effect of Ouabain on a TMZ-resistant (T98G) as compared to a TMZ-sensitive (LN229) GBM cell line.

METHODS

We analyzed the effect of Ouabain on cell migration and plasma cell membrane potential (PCMP) in the LN229 and T98G GBM cell line as well as underlying mechanisms (Bcl-2 and p-Akt/pan-Akt expression). Moreover, we analyzed the anti-angiogenic effect of Ouabain on human umbilical vein endothelial cells (HUVECs).

RESULTS

T98G cells showed a significant inhibition of cell migration and a significant depolarization of the PCMP at similar Ouabain concentrations (IC50 = 1.67 × 10^-7 M) resp. (IC50 = 2.72 × 10^-7 M) with a strong inverse correlation (R² = 0.95). In contrast, LN229 cells did not respond to Ouabain in these assays at all. Similarly, only T98G but not LN229 cells revealed Bcl-2 down-regulation at nanomolar Ouabain concentrations. This unique response to Ouabain is associated with a down-regulation of pan-Akt in T98G cells 24 h after Ouabain (1.0 × 10^-6 M) treatment. For the first time, the anti-angiogenic effect of Ouabain on HUVEC cells (IC50 = 5.49 × 10^-8 M) was demonstrated which correlated strongly with the anti-migratory effect (R² = 0.85).

CONCLUSION

The TMZ-resistant T98G cell line as compared to the TMZ-sensitive LN229 cell line shows a high sensitivity towards Ouabain. We consider it as a promising new compound especially in recurrent GBM to overcome the resistance to TMZ and irradiation.

Sprouty 4 suppresses glioblastoma invasion by inhibiting ERK phosphorylation and ETS-1-induced matrix metalloproteinase-9

BACKGROUND

Glioblastoma multiforme (GBM) is the most malignant glioma with highly aggressive behavior and the worst prognosis. Many efforts have been made to develop new drugs and improve the patient's survival, but the effects are not satisfactory. Here we aimed to evaluate the clinical significance and tumor-repressive function of Sprouty4 (SPRY4) in GBM.

METHODS

In our study, we detected the expression of SPRY4 in 109 GBM patients and 12 pairs of GBM tissues and the corresponding adjacent tissues. χ² test was applied to analyze the association between SPRY4 expression and the clinicopathological factors. The prognostic significances were evaluated with univariate and multivariate analyses, which were carried out by the Kaplan-Meier method and the Cox-regression proportional hazards model, respectively. With in-vitro experiments, we investigated the tumor-suppressing function of SPRY4 in GBM invasion and investigated the underlying mechanism.

RESULTS

SPRY4 mRNAs in GBMs were significantly lower than those in adjacent brain tissues. We demonstrated that SPRY4 expression could predict the favorable prognosis of GBM, and SPRY4 was an independent favorable prognostic factor of GBM. SPRY4 repressed GBM invasion via inhibiting ERK phosphorylation; therefore, suppressing ETS-1-induced MMP9 expression.

CONCLUSIONS

SPRY4 was an independent favorable prognostic factor of GBM, and it could suppress GBM invasion by ERK-ETS-MMP9 axis. Our results indicated that SPRY4 may be a promising drug target of GBM and SPRY4 detection could stratify patients with low SPRY4 expression who may benefit from anti-FGFR therapy.

Impact of fractionated stereotactic radiotherapy on activity of daily living and performance status in progressive/recurrent glioblastoma: a retrospective study

BACKGROUND

The prognosis of recurrent glioblastoma (GBM) is poor, with limited options of palliative localized or systemic treatments. Survival can be improved by a second localized treatment; however, it is not currently possible to identify which patients would benefit from this approach. This study aims to evaluate which factors lead to a lower Karnofsky performance status (KPS) score after fractionated stereotactic RT (fSRT).

METHODS

We retrospectively collected data from patients treated with fSRT for recurrent GBM at the Institut de Cancérologie de Lorraine between October 2010 and November 2017 and analyzed which factors were associated with a lower KPS score.

RESULTS

59 patients received a dose of 25 Gy in 5 sessions spread over 5-7 days (80% isodose). The median time from the end of primary radiotherapy to the initiation of fSRT was 10.7 months. The median follow-up after fSRT initiation was 8.8 months. The incidence of KPS and ADL impairment in all patients were 51.9% and 37.8% respectively with an adverse impact of PTV size on KPS (HR = 1.57 [95% CI 1.19-2.08], p = 0.028). Only two patients showed early grade 3 toxicity and none showed grade 4 or late toxicity. The median overall survival time, median overall survival time after fSRT, median progression-free survival and institutionalization-free survival times were 25.8, 8.8, 3.9 and 7.7 months, respectively. Initial surgery was associated with better progression-free survival (Hazard ratio (HR) = 0.48 [95% CI 0.27-0.86], p = 0.013).

CONCLUSIONS

A larger PTV should predicts lower KPS in the treatment of recurrent GBM using fSRT.

Notch intracellular domain regulates glioblastoma proliferation through the Notch1 signaling pathway

Notch intracellular domain (NICD), also known as the activated form of Notch1 is closely associated with cell differentiation and tumor invasion. However, the role of NICD in glioblastoma (GBM) proliferation and the underlying regulatory mechanism remains unclear. The present study aimed to investigate the expression of NICD and Notch1 downstream gene HES5 in human GBM and normal brain samples and to further detect the effect of NICD on human GBM cell proliferation. For this purpose, western blotting and immunohistochemical staining were performed to analyze the expression of NICD in human GBM tissues, while western blotting and reverse-transcription quantitative PCR experiments were used to analyze the expression of Hes5 in human GBM tissues. A Flag-NICD vector was used to overexpress NICD in U87 cells and compound E and small interfering (si) Notch1 were used to downregulate NICD. Cellular proliferation curves were generated and BrdU assays performed to evaluate the proliferation of U87 cells. The results demonstrated that compared with normal brain tissues, the level of NICD protein in human GBM tissues was upregulated and the protein and mRNA levels of Hes5 were also upregulated in GBM tissues indicating that the Notch1 signaling pathway is activated in GBM. Overexpression of NICD promoted the proliferation of U87 cells in vitro while downregulation of NICD by treatment with compound E or siNotch1 suppressed the proliferation of U87 cells in vitro. In conclusion, NICD was upregulated in human GBM and NICD promoted GBM proliferation via the Notch1 signaling pathway. NICD may be a potential diagnostic marker and therapeutic target for GBM treatment.

Mir-29c Expression in Glioma and Its Effects on Tumor Cell Proliferation and Apoptosis

BACKGROUND

To investigate the expression of microRNA-29c (miR-29c) in glioma and its effects on cell proliferation and apoptosis.

METHODS

A retrospective analysis was performed on 76 glioma patients in People's Hospital of Weifang, Weifang, Shandong, China from May 2013 to June 2017 (experimental group) and 63 healthy subjects in the same period (control group). qRT-PCR was used to detect the miR-29c expression. Changes of serum miR-29c expression level and the correlation of miR-29c of glioma patients with the degree of tumor differentiation and pathological type were observed. Cells were grouped before transfection into blank group (no transfection), negative control group (transfected with miRNA NC) and experimental group (transfected with miR-29c mimics). CCK-8 assay was used to detect cell proliferation, flow cytometry to detect apoptosis.

RESULTS

Expression of miR-29c in serum was significantly lower in experimental group than that in control group (P<0.05). The expression level of miR-29c of glioma patients increased with the degree of tumor differentiation (P<0.05). miR-29c in serum was not significantly correlated with the pathological type.

CONCLUSION

miR-29c could inhibit the proliferation of glioma cells and promote apoptosis. miR-29c is lowly expressed in glioma, and the overexpression of which in glioma cells can inhibit tumor cells proliferation and promote apoptosis. It may be a tumor suppressor miRNA of glioma, and the expression level of which can be used as reference for evaluating the grade of glioma. It is indicated that the abnormal expression of miR-29c may be a key factor in the occurrence and development of glioma.

Signal transduction pathways and resistance to targeted therapies in glioma

Although surgical techniques and adjuvant therapies have undergone progressive development for decades, the therapeutic outcomes for treating glioblastoma (GBM) remain poor. The main reasons for the poor prognosis of gliomas are that limited tumor tissue that can be resected (to preserve brain functions) and that residual tumors are often resistant to irradiation and chemotherapy. Therefore, overcoming the resistance of residual tumors against adjuvant therapy is urgently needed for glioma treatment. Recent large cohort studies of genetic alterations in GBM demonstrated that both genetic information and intracellular molecular signaling are networked in gliomas and that such information may help clarify which molecules or signals serve essential roles in resistance against radiation or chemotherapy, highlighting them as potential novel therapeutic targets against refractory gliomas. In this review, we summarize the current understanding of molecular networks that govern glioma biology, mainly based on cohort studies or recent evidence, with a focus on how intracellular signaling molecules in gliomas associate with each other and regulate refractoriness against current therapy.

The added prognostic value of radiological phenotype combined with clinical features and molecular subtype in anaplastic gliomas

PURPOSE

To determine whether radiological phenotype can improve the predictive performance of the risk model based on molecular subtype and clinical risk factors in anaplastic glioma patients.

METHODS

This retrospective study was approved by our institutional review board with waiver of informed consent. MR images of 86 patients with pathologically diagnosed anaplastic glioma (WHO grade III) between January 2007 and February 2016 were analyzed according to the Visually Accessible Rembrandt Images (VASARI) features set. Significant imaging findings were selected to generate a radiological risk score (RRS) for overall survival (OS) and progression-free survival (PFS) using the least absolute shrinkage and selection operator (LASSO) Cox regression model. The prognostic value of RRS was evaluated with multivariate Cox regression including molecular subtype and clinical risk factors. The C-indices of multivariate models with and without RRS were compared by bootstrapping.

RESULTS

Eight VASARI features contributed to RRS for OS and six contributed to PFS. Multifocality or multicentricity was the most influential feature, followed by restricted diffusion. RRS was significantly associated with OS and PFS (P < .001), as well as age and molecular subtype. The multivariate model with RRS demonstrated a significantly higher predictive performance than the model without (C-index difference: 0.074, 95% confidence interval [CI]: 0.031, 0.148 for OS; C-index difference: 0.054, 95% CI: 0.014, 0.123 for PFS).

CONCLUSION

RRS derived from VASARI features was an independent predictor of survival in patients with anaplastic gliomas. The addition of RRS significantly improved the predictive performance of the molecular feature based model.

Using Smaller-Than-Standard Radiation Treatment Margins Does Not Change Survival Outcomes in Patients with High-Grade Gliomas

PURPOSE

The number of studies that evaluate treatment margins for high grade gliomas (HGG) are limited. We hypothesize that patients with HGG who are treated with a gross tumor volume (GTV) to planning tumor volume (PTV) expansion of ≤1 cm will have progression-free survival (PFS) and overall survival (OS) rates similar to those treated in accordance with standard protocols by the Radiation Therapy Oncology Group or European Organisation for Research and Treatment of Cancer. Furthermore, the PFS and OS of subgroups within the study population will have equivalent survival outcomes with GTV1-to-PTV1 margins of 1.0 cm and 0.4 cm.

METHODS AND MATERIALS

Treatment plans and outcomes for patients with pathologically confirmed HGG were analyzed (n = 267). Survival (PFS and OS) was calculated from the time of the first radiation treatment and a χ² test or Fisher exact test was used to calculate the associations between margin size and patient characteristics. Survival was estimated using Kaplan-Meier and compared using the log-rank test. All analyses were performed on the univariate level.

RESULTS

The median PFS and OS times were 10.6 and 19.1 months, respectively. By disease, the median PFS and OS times were 8.6 and 16.1 months for glioblastoma and 26.7 and 52.5 months for anaplastic glioma. The median follow-up time was 18.3 months. The treatment margin had no effect on outcome and the 1.0 cm GTV1-PTV1 margin subgroup (n = 212) showed median PFS and OS times of 10.7 and 19.1 months, respectively, and the 0.4 cm margin subgroup (n = 55) 10.2 and 19.3 months, respectively. In comparison with the standard treatment with 2 cm to 3 cm margins, there was not a significant difference in outcomes.

CONCLUSIONS

There is no apparent difference in survival when utilizing smaller versus larger margins as defined by the guidelines of the Radiation Therapy Oncology Group and European Organisation for Research and Treatment of Cancer. Although there remains no class I evidence that outcomes after treatment with smaller margins are identical to those after treatment with larger margins, this large series with long-term follow up suggests that a reduction of the margins is safe and further investigation is warranted.

Drug Delivery Nanosystems for the Localized Treatment of Glioblastoma Multiforme

Glioblastoma multiforme is one of the most prevalent and malignant forms of central nervous system tumors. The treatment of glioblastoma remains a great challenge due to its location in the intracranial space and the presence of the blood⁻brain tumor barrier. There is an urgent need to develop novel therapy approaches for this tumor, to improve the clinical outcomes, and to reduce the rate of recurrence and adverse effects associated with present options. The formulation of therapeutic agents in nanostructures is one of the most promising approaches to treat glioblastoma due to the increased availability at the target site, and the possibility to co-deliver a range of drugs and diagnostic agents. Moreover, the local administration of nanostructures presents significant additional advantages, since it overcomes blood⁻brain barrier penetration issues to reach higher concentrations of therapeutic agents in the tumor area with minimal side effects. In this paper, we aim to review the attempts to develop nanostructures as local drug delivery systems able to deliver multiple agents for both therapeutic and diagnostic functions for the management of glioblastoma.

Re-irradiation for recurrent glioma- the NCI experience in tumor control, OAR toxicity and proposal of a novel prognostic scoring system

Purpose/objectives

Despite mounting evidence for the use of re-irradiation (re-RT) in recurrent high grade glioma, optimal patient selection criteria for re-RT remain unknown. We present a novel scoring system based on radiobiology principles including target independent factors, the likelihood of target control, and the anticipated organ at risk (OAR) toxicity to allow for proper patient selection in the setting of recurrent glioma.

Materials/methods

Thirty one patients with recurrent glioma who received re-RT (2008–2016) at NCI – NIH were included in the analysis. A novel scoring system for overall survival (OS) and progression free survival (PFS) was designed to include:1) target independent factors (age, KPS (Karnofsky Performance Status), histology, presence of symptoms), 2) target control, and 3) OAR toxicity risk. Normal tissue complication probability (NTCP) calculations were performed using the Lyman model. Kaplan-Meier analysis was performed for overall survival (OS) and progression free survival (PFS) for comparison amongst variables.

Results

No patient, including those who received dose to OAR above the published tolerance dose, experienced any treatment related grade 3–5 toxicity with a median PFS and OS from re-RT of 4 months (0.5–103) and 6 months (0.7–103) respectively. Based on cumulative maximum doses the average NTCP was 25% (0–99%) for the chiasm, 21% (0–99%) for the right optic nerve, 6% (0–92%) for the left optic nerve, and 59% (0–100%) for the brainstem. The independent factor and target control scores were each statistically significant for OS and the combination of independent factors plus target control was also significant for both OS (p = 0.02) and PFS (p = 0.006). The anticipated toxicity risk score was not statistically significant.

Conclusion

Our scoring system may represent a novel approach to patient selection for re-RT in recurrent high grade glioma. Further validation in larger patient cohorts including compilation of doses to tumor and OAR may help refine this further for inclusion into clinical trials and general practice.

Electronic supplementary material

The online version of this article (10.1186/s13014-017-0930-9) contains supplementary material, which is available to authorized users.

Combination Treatment with the GSK-3 Inhibitor 9-ING-41 and CCNU Cures Orthotopic Chemoresistant Glioblastoma in Patient-Derived Xenograft Models

Resistance to chemotherapy remains a major challenge in the treatment of human glioblastoma (GBM). Glycogen synthase kinase-3β (GSK-3β), a positive regulator of NF-κB–mediated survival and chemoresistance of cancer cells, has been identified as a potential therapeutic target in human GBM. Our objective was to determine the antitumor effect of GSK-3 inhibitor 9-ING-41 in combination with chemotherapy in patient-derived xenograft (PDX) models of human GBM. We utilized chemoresistant PDX models of GBM, GBM6 and GBM12, to study the effect of 9-ING-41 used alone and in combination with chemotherapy on tumor progression and survival. GBM6 and GBM12 were transfected by reporter constructs to enable bioluminescence imaging, which was used to stage animals prior to treatment and to follow intracranial GBM tumor growth. Immunohistochemical staining, apoptosis assay, and immunoblotting were used to assess the expression of GSK-3β and the effects of treatment in these models. We found that 9-ING-41 significantly enhanced 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) antitumor activity in staged orthotopic GBM12 (no response to CCNU) and GBM6 (partial response to CCNU) PDX models, as indicated by a decrease in tumor bioluminescence in mouse brain and a significant increase in overall survival. Treatment with the combination of CCNU and 9-ING-41 resulted in histologically confirmed cures in these studies. Our results demonstrate that the GSK-3 inhibitor 9-ING-41, a clinical candidate currently in Investigational New Drug (IND)-enabling development, significantly enhances the efficacy of CCNU therapy for human GBM and warrants consideration for clinical evaluation in this difficult-to-treat patient population.

FLAIR signal increase of the fluid within the resection cavity after glioma surgery: generally valid as early recurrence marker?

OBJECTIVE Recent studies have indicated that a signal intensity increase of the fluid within the resection cavity on FLAIR images may predict tumor recurrence after glioma surgery. The aim of this study was to assess the increase in FLAIR signal intensity in a large patient cohort and in subgroups to assess its prognostic value for early tumor recurrence in glioma patients. METHODS A total of 212 patients (213 cases) who had undergone surgery for an intracranial glioma (WHO Grade IV [n = 103], WHO Grade III [n = 57], and WHO Grade II [n = 53]) were included in this retrospective study. FLAIR signal within the resection cavity at the time of tumor recurrence/last contact and on the previous MRI study was assessed qualitatively and quantitatively. Appearance of FLAIR signal increase was studied over time using Kaplan-Meier estimates in subgroups. RESULTS Patients with WHO Grade II glioma and connection of the resection cavity to CSF who did not undergo radiotherapy did not regularly develop this sign and were excluded from further analysis. For the remaining 87 cases, FLAIR signal intensity increase was observed in 27 cases. Recurrent disease was found in 26 of these 27 cases, resulting in a specificity of 80.0%, a sensitivity of 31.7%, and positive and negative predictive values of 96.3% and 6.7%, respectively. In 4 cases this sign had been observed prior (range 2.8-8.5 months) to tumor recurrence defined by standard criteria. Quantitative analysis underlined the results of qualitative analysis, but it did not add a diagnostic value. CONCLUSIONS Signal intensity increase of the fluid within the resection cavity on FLAIR images is a rare but highly specific and early sign for tumor recurrence/tumor progression in completely and incompletely resected high-grade glioma without connection of the resection cavity to CSF and with radiotherapy.

Golgi Phosphoprotein 3 Inhibits the Apoptosis of Human Glioma Cells in Part by Downregulating N-myc Downstream Regulated Gene 1

Background

Golgi phosphoprotein 3 (GOLPH3) has been reported to be involved in the development of several human cancers. Our previous study showed that GOLPH3 expression in glioma tissues was related to the severity of the malignancy of the cancer. However, the mechanism by which GOLPH3 affects cell apoptosis is largely unknown. The present study was designed to explore the possible mechanism of GOLPH3 in cell apoptosis.

Material/Methods

To analyze the biological role of GOLPH3 in glioma cells, we used GOLPH3 small interference RNA in apoptosis of glioma cells. The apoptosis of glioma cells was detected by flow cytometry. The expression level of GOLPH3 and NDRG1 protein was determined by Western blot analyses and immunohistochemical staining, respectively, to evaluate their association with glioma. Tumor tissues were collected from patients with glioma. Normal cerebral tissues were acquired from cerebral trauma patients undergoing internal decompression surgery.

Results

We confirm that the decrease of GOLPH3 that promotes the apoptosis of glioma cells may be regulated by the activation of NDRG1 and cleaved capcase 3. There was a inverse association between GOLPH3 and NDRG1 in glioma samples.

Conclusions

Our findings indicate that GOLPH3 and NDRG1 both play an important role in glioma etiology. Either GOLPH3 or NDRG1 might be a potential candidate for malignant glioma therapy.

Early Biomarkers from Conventional and Delayed-Contrast MRI to Predict the Response to Bevacizumab in Recurrent High-Grade Gliomas

BACKGROUND AND PURPOSE

The interpretation of the radiologic response of bevacizumab-treated patients with recurrent high-grade gliomas represents a unique challenge. Delayed-contrast MR imaging was recently introduced for calculating treatment-response-assessment maps in patients with brain tumors, providing clear separation between active tumor and treatment effects. We studied the application of standard and delayed-contrast MR imaging for assessing and predicting the response to bevacizumab.

MATERIALS AND METHODS

Twenty-four patients with recurrent high-grade gliomas were scanned before and during bevacizumab treatment by standard and delayed-contrast MR imaging. The mean change in lesion volumes of responders (overall survival, ≥1 year) and nonresponders (overall survival, <1 year) was studied. The lesion volumes at baseline and the changes in lesion volumes 1 month after treatment initiation, calculated from standard and delayed-contrast MRIs, were studied as possible predictors of outcome. In scans acquired at progression, the average change in lesion volume from previous follow-up in standard and delayed-contrast MRIs was compared.

RESULTS

Response and progression patterns were identified from the mean change in lesion volumes, depicted from conventional T1WI, delayed contrast-enhanced MR imaging, and DSC MR imaging. Thresholds for early prediction of response were calculated by using these sequences. For each predictor, sensitivity, specificity, positive predictive values, and negative predictive values were calculated, reaching 85.7%, 87.5%, 75%, and 93.3% for conventional T1WI; 100%, 87.5%, 77.8%, and 100% for delayed-contrast MR imaging; and 75%, 78.6%, 50%, and 91.7% for DSC MR imaging. The benefit of delayed-contrast MR imaging in separating responders and nonresponders was further confirmed by using log-rank tests (conventional T1WI, P = .0022; delayed-contrast MR imaging, P < .0001; DSC MR imaging, P = .0232) and receiver operating characteristic analyses. At progression, the increase in lesion volumes in delayed-contrast MR imaging was 37.5% higher than the increase in conventional T1WI (P < .01); these findings suggest that progression may be depicted more effectively in treatment-response-assessment maps.

CONCLUSIONS

The benefit of contrast-enhanced MR imaging for assessing and predicting the response to bevacizumab was demonstrated. The increased sensitivity of the treatment-response-assessment maps reflects their potential contribution to the management of bevacizumab-treated patients with recurrent high-grade glioma.

Toca 511 plus 5-fluorocytosine in combination with lomustine shows chemotoxic and immunotherapeutic activity with no additive toxicity in rodent glioblastoma models

BACKGROUND

Toca 511, a gamma retroviral replicating vector encoding cytosine deaminase, used in combination with 5-fluorocytosine (5-FC) kills tumor by local production of 5-fluorouracil (5-FU), inducing local and systemic immunotherapeutic response resulting in long-term survival after cessation of 5-FC. Toca 511 and Toca FC (oral extended-release 5-FC) are under investigation in patients with recurrent high-grade glioma. Lomustine is a treatment option for patients with high-grade glioma.

METHODS

We investigated the effects of lomustine combined with Toca 511 + 5-FC in syngeneic orthotopic glioma models. Safety and survival were evaluated in immune-competent rat F98 and mouse Tu-2449 models comparing Toca 511 + 5-FC to lomustine + 5-FC or the combination of Toca 511 + 5-FC + lomustine. After intracranial implantation of tumor, Toca 511 was delivered transcranially followed by cycles of intraperitoneal 5-FC with or without lomustine at the first or fourth cycle.

RESULTS

Coadministration of 5-FC with lomustine was well tolerated. In F98, combination Toca 511 + 5-FC and lomustine increased median survival, but "cures" were not achieved. In Tu-2449, combination Toca 511 + 5-FC and lomustine increased median survival and resulted in high numbers of cure. Rejection of tumor rechallenge occurred after treatment with Toca 511 + 5-FC or combined with lomustine, but not with lomustine + 5-FC. Mixed lymphocyte-tumor cell reactions using splenocytes from cured animals showed robust killing of target cells in an effector:target ratio-dependent manner with Toca 511 + 5-FC and Toca 511 + 5-FC + lomustine day 10.

CONCLUSION

The combination of Toca 511 + 5-FC and lomustine shows promising efficacy with no additive toxicity in murine glioma models. Immunotherapeutic responses resulting in long-term survival were preserved despite lomustine-related myelosuppression.

In silico analysis suggests differential response to bevacizumab and radiation combination therapy in newly diagnosed glioblastoma

Recently, two phase III studies of bevacizumab, an anti-angiogenic, for newly diagnosed glioblastoma (GBM) patients were released. While they were unable to statistically significantly demonstrate that bevacizumab in combination with other therapies increases the overall survival of GBM patients, there remains a question of potential benefits for subpopulations of patients. We use a mathematical model of GBM growth to investigate differential benefits of combining surgical resection, radiation and bevacizumab across observed tumour growth kinetics. The differential hypoxic burden after gross total resection (GTR) was assessed along with the change in radiation cell kill from bevacizumab-induced tissue re-normalization when starting therapy for tumours at different diagnostic sizes. Depending on the tumour size at the time of treatment, our model predicted that GTR would remove a variable portion of the hypoxic burden ranging from 11% to 99.99%. Further, our model predicted that the combination of bevacizumab with radiation resulted in an additional cell kill ranging from 2.6×10⁷ to 1.1×10¹⁰ cells. By considering the outcomes given individual tumour kinetics, our results indicate that the subpopulation of patients who would receive the greatest benefit from bevacizumab and radiation combination therapy are those with large, aggressive tumours and who are not eligible for GTR.

[What's next in glioblastoma treatment: Tumor-targeted or immune-targeted therapies?]

INTRODUCTION

Glioblastoma (GBM) is associated with a poor prognosis. This review will discuss different directions of treatment, mostly regarding immunotherapies and combinatorial approaches.

DEVELOPMENT

Standard treatment for newly diagnosed GBM is maximal and safe surgical resection followed by concurrent radiochemotherapy (RCT) based on temozolomide, allowing 14.6 months median survival. Nowadays, no combination with molecular-targeted therapy had significantly improved prognosis. Phases I and II data are emerging, highlighting the potential efficacy of associations with other therapies. Studies have suggested the potential of targeting tumor stem cells, at less partially responsible for resistance to RCT. There is now some evidence that immunotherapy is also relevant for brain tumors. Treatment strategies have mainly explored vaccines strategies, such as the dendritic cell, heat shock protein or EGFRvIII vaccines. Of the work initiated in melanoma, immune checkpoints inhibitors have exhibited stimulating results. Others trials have demonstrated potential of autologous stimulated lymphocytes. Moreover, strong data indicates that radiation therapy has the potential to promote immunogenicity and create a sort of in situ personalized vaccine.

CONCLUSION

These data provide strong evidence to support the potential of associating combinatorial targeted and/or immunotherapeutic regimens in patients with GBM that may change patient outcome.

Value of Early Postoperative FLAIR Volume Dynamic in Glioma with No or Minimal Enhancement

OBJECTIVE

The evaluation of postoperative magnetic resonance imaging (MRI) in glioma with no or minimal enhancement is controversial because the evaluation of residual tumor volume can be biased. The purpose of this study was to clarify the value of early postoperative and 3-month MRI regarding its validity in predicting recurrent disease.

METHODS

For this retrospective, single-center study, overall fluid attenuated inversion recovery (FLAIR) volumes (early postoperative [<48 hours] and 3-month MRI including FLAIR and T1-weighted sequences with and without contrast agent) of 99 patients were assessed using manual segmentation. FLAIR volume dynamic over the first 3 months after surgery and its effect on disease recurrence were evaluated while considering histopathologic features.

RESULTS

Overall FLAIR-hyperintense volume significantly decreased between early postoperative and 3-month follow-up MRIs (P < 0.001). Early FLAIR volume increase had a high positive predictive value for overall disease recurrence after resection (85.71% [95%-CI: 62.64-96.24]). Early FLAIR volume dynamic (P < 0.001), isocitrate dehydrogenase 1/2 status (P = 0.002), and preoperative Karnofsky Performance Status (P = 0.012) were observed as independent factors for progression-free survival in multivariate analysis.

CONCLUSION

Early postoperative FLAIR volume assessment in gliomas with no or minimal enhancement is susceptible to a systematic overestimation of residual tumors. Nevertheless, early FLAIR volume dynamic is an independent factor for tumor recurrence that should be evaluated in order timely adapt surveillance and therapy regimens accordingly.

Advances in the treatment of newly diagnosed glioblastoma

Glioblastoma is a refractory malignancy with limited treatment options at tumor recurrence. Only a small proportion of patients survive 2 years or longer with the current standard of care. Gene expression profiling can segregate newly diagnosed patients into groups with different prognoses, and these biomarkers are being incorporated into a new generation of personalized clinical trials. Using the experience from recently completed large scale, multi-faceted, randomized glioblastoma clinical trials, a new clinical trial paradigm is being established to move promising therapies forward into the newly diagnosed treatment setting. Upcoming trials using the immune check-point inhibitors are an example of this changing paradigm and these and other immunotherapies have potential as promising new treatment modalities for newly diagnosed GB patients.

Patterns of response to crizotinib in recurrent glioblastoma according to ALK and MET molecular profile in two patients

Two patients with an unmethylated MGMT promoter and IDH1 (R132H) wild-type recurrent glioblastoma were treated with crizotinib. Prolonged stabilization of the disease (17 months) was achieved in the first case. Interestingly, anaplastic lymphoma kinase (ALK) expression and c-MET protein overexpression was observed. Conversely, no response to crizotinib was obtained in the second case with MET protein overexpression and c-MET amplification but no ALK expression or ALK gene amplification. These case studies suggest that novel targeted ALK inhibitors may provide relevant clinical benefit in selected cases in which driver mutations are demonstrable.

Expression of metastasis-associated protein 3 in human brain glioma related to tumor prognosis

Glioma represents a disparate group of tumors characterized by high invasion ability, and therefore it is of clinical significance to identify molecular markers and therapeutic targets for better clinical management. Previously, metastasis-associated protein family (MTA) is considered to promote tumor cell invasion and metastasis of human malignancies. Recently, the newly identified MTA3 has been shown to play conflicting roles in human malignancies, while the expression pattern and potential clinical significance of MTA3 in human glioma have not been addressed yet. In the present study, we investigated the protein expression of MTA3 by immunohistochemistry assay and analyzed its association with glioma prognosis in 186 cases of patients. Results showed that MTA3 expression was decreased in glioma compared with that in normal brain (P < 0.05). In addition, tumors with high MTA3 expression were more likely to be of low WHO grade (P = 0.005) and reserve of body function (P = 0.014). Survival analysis showed that decreased MTA3 expression was independently associated with unfavorable overall survival of patients (P < 0.001). These results provide the first evidence that MTA3 expression was decreased in human glioma and negatively associated with prognosis of patients, suggesting that MTA3 may play a tumor suppressor role in glioma.