Therapeutic advances in the treatment of glioblastoma: rationale and potential role of targeted agents

The role of biological macromolecules in the regulation of angiogenesis in glioblastoma: Focus on vascular growth factors, integrins, and extracellular matrix proteins

Glioblastoma, classified as a grade 4 brain tumor, accounts for approximately half of all malignant central nervous system cancers. Despite extensive research and aggressive treatment modalities, much about this disease remains elusive. The proliferation of blood vessels within glioblastoma tumors significantly contributes to their invasive nature, primarily due to the influence of vascular endothelial growth factor-A (VEGF-A). As a result, the past decade has seen a concentrated effort to explore angiogenesis, especially the VEGF signaling pathway, as a therapeutic target for glioblastoma. This investigation led to the FDA approval of bevacizumab, a monoclonal antibody against VEGF-A, for the treatment of recurrent glioblastoma. However, despite promising clinical trials and theoretical research, bevacizumab has not significantly improved patient survival rates. Furthermore, other anti-angiogenic agents targeting the VEGF signaling pathway have shown limited efficacy. This suggests the existence of multiple alternative angiogenic pathways that facilitate vascularization, even when VEGF signaling is inhibited. In this study, we aim to assess the current landscape of anti-angiogenic agents, explore potential resistance mechanisms to such therapies, and suggest strategies to improve the effectiveness of these therapeutic interventions. Our goal is to provide a comprehensive understanding of the limitations of current treatments and to identify new avenues for enhancing therapeutic outcomes in glioblastoma patients.

AT-0174, a novel dual IDO1/TDO2 enzyme inhibitor, synergises with temozolomide to improve survival in an orthotopic mouse model of glioblastoma

BACKGROUND

Glioblastoma is an aggressive brain cancer, usually of unknown etiology, and with a very poor prognosis. Survival from diagnosis averages only 3 months if left untreated and this only increases to 12-15 months upon treatment. Treatment options are currently limited and typically comprise radiotherapy plus a course of the DNA-alkylating chemotherapeutic temozolomide. Unfortunately, the disease invariably relapses after several months of treatment with temozolomide, due to the development of resistance to the drug. Increased local tryptophan metabolism is a feature of many solid malignant tumours through increased expression of tryptophan metabolising enzymes. Glioblastomas are notable for featuring increased expression of the tryptophan catabolizing enzymes indole-2,3-dioxygenase-1 (IDO1), and especially tryptophan-2,3-dioxygenase-2 (TDO2). Increased IDO1 and TDO2 activity is known to suppress the cytotoxic T cell response to tumour cells, and this has led to the proposal that the IDO1 and TDO2 enzymes represent promising immuno-oncology targets. In addition to immune modulation, however, recent studies have also identified the activity of these enzymes is important in the development of resistance to chemotherapeutic agents.

METHODS

In the current study, the efficacy of a novel dual inhibitor of IDO1 and TDO2, AT-0174, was assessed in an orthotopic mouse model of glioblastoma. C57BL/6J mice were stereotaxically implanted with GL261(luc2) cells into the striatum and then administered either vehicle control, temozolomide (8 mg/kg IP; five 8-day cycles of treatment every 2 days), AT-0174 (120 mg/kg/day PO) or both temozolomide + AT-0174, all given from day 7 after implantation.

RESULTS

Temozolomide decreased tumour growth and improved median survival but increased the infiltration of CD4+ Tregs. AT-0174 had no significant effect on tumour growth or survival when given alone, but provided clear synergy in combination with temozolomide, further decreasing tumour growth and significantly improving survival, as well as elevating CD8+ T cell expression and decreasing CD4+ Treg infiltration.

CONCLUSION

AT-0174 exhibited an ideal profile for adjunct treatment of glioblastomas with the first-line chemotherapeutic drug temozolomide to prevent development of CD4+ Treg-mediated chemoresistance.

Exosomal long non-coding RNAs in glioblastoma

Glioblastoma multiforme (GBM) is the most prevalent primary tumor found in the central nervous system, accounting for 70% of all adult brain tumors. The median overall survival rate is one year post-diagnosis with treatment, and only four months without treatment. Current GBM diagnostic methods, such as magnetic resonance imaging (MRI), surgery, and brain biopsies, have limitations. These include difficulty distinguishing between tumor recurrence and post-surgical necrotic regions, and operative risks associated with obtaining histological samples through direct surgery or biopsies. Consequently, there is a need for rapid, inexpensive, and minimally invasive techniques for early diagnosis and improved subsequent treatment. Research has shown that tumor-derived exosomes containing various long non-coding RNAs (lncRNAs) play critical regulatory roles in immunomodulation, cancer metastasis, cancer development, and drug resistance in GBM. They regulate genes that enhance cancer growth and progression and alter the expression of several key signaling pathways. Due to the specificity and sensitivity of exosomal lncRNAs, they have the potential to be used as biomarkers for early diagnosis and prognosis, as well as to monitor a patient's response to chemotherapy for GBM. In this review, we discuss the role of exosomal lncRNAs in the pathogenesis of GBM and their potential clinical applications for early diagnosis.

Temozolomide and flavonoids against glioma: from absorption and metabolism to exosomal delivery

Patients with glioblastoma multiforme and anaplastic astrocytoma are treated with temozolomide. Although it has been demonstrated that temozolomide increases GBM patient survival, it has also been connected to negative immune-related adverse effects. Numerous research investigations have shown that flavonoids have strong antioxidant and chemo-preventive effects. Consequently, it might lessen chemotherapeutic medicines' side effects while also increasing therapeutic effectiveness. The need for creating innovative, secure, and efficient drug carriers for cancer therapy has increased over time. Recent research indicates that exosomes have enormous potential to serve as carriers and cutting-edge drug delivery systems to the target cell. In recent years, researchers have been paying considerable attention to exosomes because of their favorable biodistribution, biocompatibility, and low immunogenicity. In the present review, the mechanistic information of the anti-glioblastoma effects of temozolomide and flavonoids coupled with their exosomal delivery to the targeted cell has been discussed. In addition, we discuss the safety aspects of temozolomide and flavonoids against glioma. The in-depth information of temozolomide and flavonoids action via exosomal delivery can unravel novel strategies to target Glioma.

An Analysis of Eosinophil- and Basophil-Based Indices in Patients with Glioblastoma and their Correlation with Survival

BACKGROUND

Glioblastoma (GBM) is the most frequently diagnosed malignant brain tumor in adults. GBM is usually lethal within 24 months of diagnosis, despite aggressive multimodality treatment. Although it has been established that cancer-related inflammation is associated with worse outcomes, the role of eosinophils, basophils, atopy, and allergy in glioma biology is only gradually being delineated. In this study, we aimed to examine if eosinophil-based and basophil-based indices were altered in patients with GBM compared with healthy controls. We also aimed to study if there was any correlation between these indices and patient-related and tumor-related factors and survival.

METHODS

This study was a retrospective analysis of prospectively maintained databases. Data pertaining to patient-related and tumor-related factors, hemograms, and survival data were obtained from the electronic medical records of selected patients. Correlations between eosinophil-based and basophil-based indices and these factors were studied, as was the association with overall survival.

RESULTS

All the indices were altered in patients with GBM compared with normal healthy controls. The absolute eosinophil count was higher and the neutrophils/eosinophils ratio was lower in the better prognosis groups: those with better performance status; those without features of increased intracranial pressure or altered sensorium at presentation; those with ATRX-retained tumors that did not overexpress p53; and in the long-term survivors. The total lymphocyte count/basophils ratio and the absolute eosinophil count both independently predicted survival in a multivariate analysis.

CONCLUSIONS

The absolute eosinophil count was consistently higher in the better prognosis groups and is likely to be incorporated into prognostic models for GBM.

The efficacy of temozolomide combined with levetiracetam for glioblastoma (GBM) after surgery: a study protocol for a double-blinded and randomized controlled trial

Background

Temozolomide is applied as the standard chemotherapy agent in patients with glioblastoma (GBM) after surgery. However, the benefit of this treatment for patients is limited by the invasive growth of gliomas and drug resistance. There are indications from fundamental experimental and retrospective studies that levetiracetam has the potential to improve the survival rate of patients with GBM. However, it has yet to be determined whether the combination of temozolomide and levetiracetam is more effective than standard temozolomide chemotherapy. Therefore, we designed a randomized clinical trial to investigate the therapeutic effect of the new combined regime for treating GBM.

Methods/design

This is a double-blind and randomized clinical trial conducted in a single center. One hundred forty-two patients will be recruited and screened for the inclusion and exclusion criteria. Then, eligible participants will be randomly assigned to an experimental group or a control group in a 1:1 ratio. Based on the administration of radiation therapy (RT), participants in the experimental group will be prescribed levetiracetam plus temozolomide chemotherapy for 34 weeks while participants in the control group will receive placebo tablets plus temozolomide for the same duration. A 3-year follow-up will be conducted on all patients after intervention. Accordingly, the primary outcome will be progression-free survival (PFS). The secondary endpoints include overall survival (OS), the Karnofsky Performance Status (KPS), the objective response rate (ORR), and adverse event incidence.

Discussion

It is expected that the results of this trial will provide high-level evidence regarding the clinical benefits of levetiracetam and temozolomide combined in the treatment of GBM.

Trial registration

Chinese Clinical Trial Registry, ChiCTR2100049941. Registered on 14 August 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06168-1.

Noscapine, an Emerging Medication for Different Diseases: A Mechanistic Review

Noscapine is a benzylisoquinoline alkaloid isolated from poppy extract, used as an antitussive since the 1950s, and has no addictive or euphoric effects. Various studies have shown that noscapine has excellent anti-inflammatory effects and potentiates the antioxidant defences by inhibiting nitric oxide (NO) metabolites and reactive oxygen species (ROS) levels and increasing total glutathione (GSH). Furthermore, noscapine has indicated antiangiogenic and antimetastatic effects. Noscapine induces apoptosis in many cancerous cell types and provides favourable antitumour activities and inhibitory cell proliferation in solid tumours, even drug-resistant strains, via mitochondrial pathways. Moreover, this compound attenuates the dynamic properties of microtubules and arrests the cell cycle in the G2/M phase. Noscapine can reduce endothelial cell migration in the brain by inhibiting endothelial cell activator interleukin 8 (IL-8). In fact, this study aimed to elaborate on the possible mechanisms of noscapine against different disorders.

Apoptin gene delivery by a PAMAM dendrimer modified with a nuclear localization signal peptide as a gene carrier for brain cancer therapy

In this study, we aimed to synthesize PAMAMG3 derivatives (PAMAMG3-KRRR and PAMAMG3-HKRRR), using KRRR peptides as a nuclear localization signal and introduced histidine residues into the KRRR-grafted PAMAMG3 for delivering a therapeutic, carcinoma cell-selective apoptosis gene, apoptin into human primary glioma (GBL-14) cells and human dermal fibroblasts. We examined their cytotoxicity and gene expression using luciferase activity and enhanced green fluorescent protein PAMAMG3 derivatives in both cell lines. We treated cells with PAMAMG3 derivative/apoptin complexes and investigated their intracellular distribution using confocal microscopy. The PAMAMG3-KRRR and PAMAMG3-HKRRR dendrimers were found to escape from endolysosomes into the cytosol. The JC-1 assay, glutathione levels, and Annexin V staining results showed that apoptin triggered cell death in GBL-14 cells. Overall, these findings indicated that the PAMAMG3-HKRRR/apoptin complex is a potential candidate for an effective nonviral gene delivery system for brain tumor therapy in vitro.

Radiomics, mirnomics, and radiomirRNomics in glioblastoma: defining tumor biology from shadow to light

INTRODUCTION

Glioblastoma is a highly aggressive brain tumor with an extremely poor prognosis. Genetic characterization of this tumor has identified alterations with prognostic and therapeutic impact, and many efforts are being made to improve molecular knowledge on glioblastoma. Invasive procedures, such as tumor biopsy or radical resection, are needed to characterize the tumor.

AREAS COVERED

The role of microRNA in cancer is an expanding field of research as many microRNAs have been shown to correlate with patient prognosis and treatment response. Novel methodologies like radiomics, radiogenomics, and radiomiRNomics are under evaluation to improve the amount of prognostic and predictive biomarkers available.

EXPERT OPINION

The role of radiomics, radiogenomics, and radiomiRNomic for the characterization of glioblastoma will further improve in the coming years.

The Multifaceted Role of Extracellular Vesicles in Glioblastoma: microRNA Nanocarriers for Disease Progression and Gene Therapy

Glioblastoma (GB) is the most aggressive form of brain cancer in adults, characterized by poor survival rates and lack of effective therapies. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression post-transcriptionally through specific pairing with target messenger RNAs (mRNAs). Extracellular vesicles (EVs), a heterogeneous group of cell-derived vesicles, transport miRNAs, mRNAs and intracellular proteins, and have been shown to promote horizontal malignancy into adjacent tissue, as well as resistance to conventional therapies. Furthermore, GB-derived EVs have distinct miRNA contents and are able to penetrate the blood-brain barrier. Numerous studies have attempted to identify EV-associated miRNA biomarkers in serum/plasma and cerebrospinal fluid, but their collective findings fail to identify reliable biomarkers that can be applied in clinical settings. However, EVs carrying specific miRNAs or miRNA inhibitors have great potential as therapeutic nanotools in GB, and several studies have investigated this possibility on in vitro and in vivo models. In this review, we discuss the role of EVs and their miRNA content in GB progression and resistance to therapy, with emphasis on their potential as diagnostic, prognostic and disease monitoring biomarkers and as nanocarriers for gene therapy.

A Deep Multi-Task Learning Framework for Brain Tumor Segmentation

Glioma is the most common primary central nervous system tumor, accounting for about half of all intracranial primary tumors. As a non-invasive examination method, MRI has an extremely important guiding role in the clinical intervention of tumors. However, manually segmenting brain tumors from MRI requires a lot of time and energy for doctors, which affects the implementation of follow-up diagnosis and treatment plans. With the development of deep learning, medical image segmentation is gradually automated. However, brain tumors are easily confused with strokes and serious imbalances between classes make brain tumor segmentation one of the most difficult tasks in MRI segmentation. In order to solve these problems, we propose a deep multi-task learning framework and integrate a multi-depth fusion module in the framework to accurately segment brain tumors. In this framework, we have added a distance transform decoder based on the V-Net, which can make the segmentation contour generated by the mask decoder more accurate and reduce the generation of rough boundaries. In order to combine the different tasks of the two decoders, we weighted and added their corresponding loss functions, where the distance map prediction regularized the mask prediction. At the same time, the multi-depth fusion module in the encoder can enhance the ability of the network to extract features. The accuracy of the model will be evaluated online using the multispectral MRI records of the BraTS 2018, BraTS 2019, and BraTS 2020 datasets. This method obtains high-quality segmentation results, and the average Dice is as high as 78%. The experimental results show that this model has great potential in segmenting brain tumors automatically and accurately.

Small Molecules of Marine Origin as Potential Anti-Glioma Agents

Marine organisms are able to produce a plethora of small molecules with novel chemical structures and potent biological properties, being a fertile source for discovery of pharmacologically active compounds, already with several marine-derived agents approved as drugs. Glioma is classified by the WHO as the most common and aggressive form of tumor on CNS. Currently, Temozolomide is the only chemotherapeutic option approved by the FDA even though having some limitations. This review presents, for the first time, a comprehensive overview of marine compounds described as anti-glioma agents in the last decade. Nearly fifty compounds were compiled in this document and organized accordingly to their marine sources. Highlights on the mechanism of action and ADME properties were included. Some of these marine compounds could be promising leads for the discovery of new therapeutic alternatives for glioma treatment.

The Interplay between Cancer Biology and the Endocannabinoid System-Significance for Cancer Risk, Prognosis and Response to Treatment

The various components of the endocannabinoid system (ECS), such as the cannabinoid receptors (CBRs), cannabinoid ligands, and the signalling network behind it, are implicated in several tumour-related states, both as favourable and unfavourable factors. This review analyses the ECS's complex involvement in the susceptibility to cancer, prognosis, and response to treatment, focusing on its relationship with cancer biology in selected solid cancers (breast, gastrointestinal, gynaecological, prostate cancer, thoracic, thyroid, CNS tumours, and melanoma). Changes in the expression and activation of CBRs, as well as their ability to form distinct functional heteromers affect the cell's tumourigenic potential and their signalling properties, leading to pharmacologically different outcomes. Thus, the same ECS component can exert both protective and pathogenic effects in different tumour subtypes, which are often pathologically driven by different biological factors. The use of endogenous and exogenous cannabinoids as anti-cancer agents, and the range of effects they might induce (cell death, regulation of angiogenesis, and invasion or anticancer immunity), depend in great deal on the tumour type and the specific ECS component that they target. Although an attractive target, the use of ECS components in anti-cancer treatment is still interlinked with many legal and ethical issues that need to be considered.

Targeting tumor hypoxia and mitochondrial metabolism with anti-parasitic drugs to improve radiation response in high-grade gliomas

High-grade gliomas (HGGs), including glioblastoma and diffuse intrinsic pontine glioma, are amongst the most fatal brain tumors. These tumors are associated with a dismal prognosis with a median survival of less than 15 months. Radiotherapy has been the mainstay of treatment of HGGs for decades; however, pronounced radioresistance is the major obstacle towards the successful radiotherapy treatment. Herein, tumor hypoxia is identified as a significant contributor to the radioresistance of HGGs as oxygenation is critical for the effectiveness of radiotherapy. Hypoxia plays a fundamental role in the aggressive and resistant phenotype of all solid tumors, including HGGs, by upregulating hypoxia-inducible factors (HIFs) which stimulate vital enzymes responsible for cancer survival under hypoxic stress. Since current attempts to target tumor hypoxia focus on reducing oxygen demand of tumor cells by decreasing oxygen consumption rate (OCR), an attractive strategy to achieve this is by inhibiting mitochondrial oxidative phosphorylation, as it could decrease OCR, and increase oxygenation, and could therefore improve the radiation response in HGGs. This approach would also help in eradicating the radioresistant glioma stem cells (GSCs) as these predominantly rely on mitochondrial metabolism for survival. Here, we highlight the potential for repurposing anti-parasitic drugs to abolish tumor hypoxia and induce apoptosis of GSCs. Current literature provides compelling evidence that these drugs (atovaquone, ivermectin, proguanil, mefloquine, and quinacrine) could be effective against cancers by mechanisms including inhibition of mitochondrial metabolism and tumor hypoxia and inducing DNA damage. Therefore, combining these drugs with radiotherapy could potentially enhance the radiosensitivity of HGGs. The reported efficacy of these agents against glioblastomas and their ability to penetrate the blood-brain barrier provides further support towards promising results and clinical translation of these agents for HGGs treatment.

Functional variations of NFKB1 and NFKB1A in inflammatory disorders and their implication for therapeutic approaches

Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) is a sophisticated transcription factor that is particularly important in the inflammatory response, but it regulates more than 400 individual and dependent genes for parts of the apoptotic, angiogenic, and proliferative, differentiative, and cell adhesion pathways. NF-κB function is directly inhibited by the binding of inhibitor of κB (IκB), and the imbalance between NF-κB and IκB has been linked to the development and progression of cancer and a variety of inflammatory disorders. These observations might broaden the horizon of current knowledge, particularly on the pathogenesis of inflammatory diseases considering the roles of NF-κB and IκB. In this context, we focus this narrative review on a comparative discussion of our findings with other literature regarding variations of NFKB1 and NFKB1A and their association with susceptibility to widespread inflammatory disorders (such as atherosclerosis, morbid obesity, Behçet syndrome, Graves disease, Hashimoto disease) and common cancers (such as gliomas).

MiRNA-7 Replacement Effect on Proliferation and Tarceva-Sensitivity in U373-MG Cell Line

BACKGROUND

Deregulation of the EGFR signaling pathway activity has been shown to can be effective in resistance to EGFR-TKIs, such as Tarceva (erlotinib), in glioblastoma cells. In addition, reports have shown that the reduction of miRNA-7 expression levels is associated with an increase in the expression of EGFR. Here, we evaluated the effect of miRNA-7 on EGFR expression and sensitivity of the U373-MG glioblastoma to erlotinib.

METHODS

The effect of miRNA-7 on EGFR expression was examined using RT-qPCR and western blotting. Trypan blue and MTT assays were performed to explore the effect of treatments on cell growth and survival, respectively. The combination index analysis was used to evaluate the interaction between drugs. Apoptosis was measured by ELISA cell death assay.

RESULTS

We showed that miRNA-7 markedly inhibited the expression of EGFR and decreased the growth of glioblastoma cells, relative to blank control and negative control miRNA (p < 0.05). Introduction of miRNA-7 synergistically increased the sensitivity of the U373-MG cells to erlotinib. Results of apoptosis assay demonstrated that miRNA-7 can trigger apoptosis and enhance the erlotinib-mediated apoptosis.

CONCLUSIONS

Our results show that miRNA-7 plays a critical role in the growth, survival and sensitivity of the U373-MG cells to erlotinib by targeting EGFR. Thus, miRNA-7 replacement therapy can become an effective therapeutic procedure in glioblastoma.

LncRNA PSMB8-AS1 acts as ceRNA of miR-22-3p to regulate DDIT4 expression in glioblastoma

Glioblastoma (GBM) is known to be one of the most fatal malignanies in central nerve system. Unfortunately, the therapies for glioblastoma still calls for further improvements. Increasing evidences have shown that the aberrant expression of long non-coding RNAs (lncRNAs) is highly relevant to glioma tumorigenesis and prognosis of GBM patients. High expression trends of lncRNA PSMB8-AS1 was observed in both glioblastoma tissues and cells. In return, GBM cell proliferation, apoptosis and radioresistance were regulated by PSMB8-AS1. In the meantime, PSMB8-AS1 mainly located in cytoplasm of glioblastoma cells, indicating post-transcriptional regulation. MiRNA-22-3p was found to contain potential binding site with PSMB8-AS1. On the other hand, low expression of miR-22-3p was exhibited in glioblastoma tissues and cells. Besides, PSMB8-AS1 and miR-22-3p had mutual suppression on the expression of each other in GBM cells. Furthermore, overexpression of PSMB8-AS1 promoted the level of DDIT4 through inhibiting miR-22-3p. Rescue assays demonstrated that overexpression of DDIT4 counteracted the impact of proliferation, apoptosis and radioresistance silencing PSMB8-AS1 lay on glioblastoma cell. Taken together, lncRNA PSMB8-AS1 acts as miR-22-3p sponge to mediate DDIT4 expression and regulate glioblastoma progression. PSMB8-AS1 might become a therapeutic target in the future.

Current promising treatment strategy for glioblastoma multiform: A review

Glioblastoma multiform (GBM) is a heterogeneous group of primary neoplasm resistant to conventional therapies. Due to their infiltrative nature it not fully isolated by aggressive surgery, radiation and chemotherapy showing poor prognosis in glioma patients. Unfortunately, diagnosed patients die within 1.5-2 year treatment schedule. Currently temozolomide (TMZ) is the first choice for the prognosis of GBM patients. TMZ metabolites methyl triazen imidazol carboxamide form complex with alkyl guanine alkyl transferase (O6 MGMT- DNA repair protein) induced DNA damage following resistance properties of TMZ and inhibit the overall survival of the patients. Last few decades different TMZ conjugated strategy is developed to overcome the resistance and enhance the chemotherapy efficacy. The main aim of this review is to introduce the new promising pharmaceutical candidates that significantly influence the therapeutic response of the TMZ in context of targeted therapy of glioblastoma patients. It is hoped that this proposed strategy are highly effective to overcome the current resistance limitations of TMZ in GBM patients and enhance the survival rate of the patients.

Increased incidence of second primary malignancy in patients with malignant astrocytoma: a population-based study

We identified patients diagnosed with malignant astrocytoma (MA) as the first of two or more primary malignancies between 1973 and 2015 from Surveillance, Epidemiology and End Results (SEER) database. Multiple primaries-standardized incidence ratio (MP-SIR) was calculated to quantitate the risk of second primary malignancy (SPM). We further identified the risk factors of developing SPM and factors affecting overall survival (OS) in MA patients with SPM. Our results revealed that overall risk of SPM among MA patients was significantly higher than that in general population (SIR: 1.09, 95% confidence interval (CI): 1–1.18, P<0.05). Specific sites where the risk of SPM increased included salivary gland, bone and joints, soft tissue including heart, brain, cranial nerves other nervous system, thyroid, acute non-lymphocytic leukemia and acute myeloid leukemia. Overall risk of SPM in patients aged ≤29 and 30–59 years significantly increased (4.34- and 1.41-fold respectively). Whereas patients aged ≥60 years had a significantly decreased risk of SPM. Patients in the group of latency at 36–59, 60–119 and ≥120 months carried significantly increased overall risk of SPM. Multivariate analysis revealed that age, race, marital status, WHO grade, differentiated grade of cancer tissues, latency was independent predictor of OS in MA patients with SPM, which were all selected into the nomogram. The calibration curve for probability of survival showed good agreement between prediction by nomogram and actual observation. In conclusion, MA survivors should be advised of their increased risk for developing certain cancers in their lifetime. Our study had clinical implications for the surveillance of MA survivors at risk of developing SPM.

Polyplexes of Functional PAMAM Dendrimer/Apoptin Gene Induce Apoptosis of Human Primary Glioma Cells In Vitro

Highly efficient and safe gene delivery has become an important aspect of neuronal gene therapy. We evaluated the ability of polyamidoamine (PAMAM) dendrimer grafted with phenylalanine, histidine, and arginine (PAMAM-FHR), a nonviral gene delivery vector, to deliver a therapeutic, tumor cell-specific killer gene, apoptin, into the human primary glioma cell line GBL-14 and human dermal fibroblasts. We performed a transfection assay using plasmids of luciferase and enhanced green fluorescent protein (EGFP) and assessed cell viability. Both cell lines were treated with complexes of PAMAM-FHR and apoptin after which their intracellular uptake and localization were examined by fluorescence-activated cell sorting (FACS)analysis and confocal laser scanning microscopy. Confocal microscopy showed that the PAMAM-FHR escaped from the endo-lysosome into the cytosol. Cell cycle phase distribution analysis, annexin V staining, and a tetramethylrhodamine ethyl ester (TMRE) assay established that apoptin triggered apoptosis in the GBL-14 cell line but not in normal fibroblasts. These results indicated that the PAMAM-FHR/apoptin complex is an effective gene vehicle for cancer therapy in vitro.

Upregulated AHIF-mediated radioresistance in glioblastoma

Long non-coding RNAs (lncRNAs) play vital roles in the pathobiology of glioblastoma multiforme (GBM). Though radiotherapy remains the most effective component of multiple therapies for patients with GBM, lncRNAs conferring GBM radioresistance are less unknown. Here, the present study identified that the antisense transcript of hypoxia-inducible factor-1α (AHIF) was upregulated in GBM cells after radiotherapy. The deregulation of AHIF affected GBM cell clonogenic formation, DNA repair and apoptosis. Notably, knockdown of AHIF inhibited tumorigenesis after radiotherapy in vivo. Further biochemical analysis identified that AHIF regulated proteins associated with apoptosis after radiotherapy. Thus, the present data illustrate that suppression of AHIF increases radiosensitivity in GBM cells, which may be a potential diagnostic and therapeutic target for GBM patients.

Variations in Toll-like receptor and nuclear factor-kappa B genes and the risk of glioma

PURPOSE

Glioblastoma (GBM) is the most aggressive primary brain tumour in the adult nervous system and is associated with a poor prognosis. NF-KB activation is an important driver of the malignant phenotype that confers a negative prognosis in patients with GBM. NF-KB plays a role in Toll-like Receptors (TLR)-induced tumourigenesis. The aim of the present study was to investigate the association of a promoter region polymorphism of NFKB1 gene encoding the p50 subunit of NF-KB, namely -94ins/del ATTG, the most widely discussed the TLR2 Arg753Gln, TLR4Asp299Gly and TLR4Thr399Ile polymorphisms, their combined effects, and the glioma risk.

METHODS

A group of 120 Glioma patients and 225 control subjects were screened for these four polymorphisms using the PCR-RFLP method.

RESULTS

Statistical analysis indicates that the ins/ins genotype of NFKB -94ins/delATTG (p=0.003), and the AA genotype of TLR4Asp299Gly (p < 0.001) are risk factors for glioma and people carrying the ins allele have an approximately 1.47 times susceptibility risk of glioma whereas GG genotype of TLR2Arg753Gln seems to be protective against glioma (p = 0.002). Combined genotype analysis showed that del/ins-GG genotype of TLR2Arg753Gln-NFKB1, del/ins + GG genotype of TLR4Asp299Gly-NFKB1, del/ins-CC genotype of TLR4Thr399Ile-NFKB1 were risk factors for glioma development.

CONCLUSION

NFKB1 -94ins/delATTG and TLR4Asp299Gly polymorphisms are associated with increased glioma cancer risk in a Turkish population.

Use of Mendelian andomization for dentifying isk actors for rain umors

Gliomas are a group of primary brain tumors, the most common and aggressive subtype of which is glioblastoma. Glioblastoma has a median survival of just 15 months after diagnosis. Only previous exposure to ionizing radiation and particular inherited genetic syndromes are accepted risk factors for glioma; the vast majority of cases are thought to occur spontaneously. Previous observational studies have described associations between several risk factors and glioma, but studies are often conflicting and whether these associations reflect true casual relationships is unclear because observational studies may be susceptible to confounding, measurement error and reverse causation. Mendelian randomization (MR) is a form of instrumental variable analysis that can be used to provide supporting evidence for causal relationships between exposures (e.g., risk factors) and outcomes (e.g., disease onset). MR utilizes genetic variants, such as single nucleotide polymorphisms (SNPs), that are robustly associated with an exposure to determine whether there is a causal effect of the exposure on the outcome. MR is less susceptible to confounding, reverse causation and measurement errors as it is based on the random inheritance during conception of genetic variants that can be relatively accurately measured. In previous studies, MR has implicated a genetically predicted increase in telomere length with an increased risk of glioma, and found little evidence that obesity related factors, vitamin D or atopy are causal in glioma risk. In this review, we describe MR and its potential use to discover and validate novel risk factors, mechanistic factors, and therapeutic targets in glioma.

Chemoresistance caused by the microenvironment of glioblastoma and the corresponding solutions

Glioblastoma multiforme (GBM) is the most common and aggressive primary human brain tumor. Although comprehensive therapies combining radiotherapy and chemotherapy after surgery can prolong survival, the prognosis is still poor with a median survival of only 14.6 months. Chemoresistance is one of the major causes of relapse as well as poor survival in glioma patients. Therefore, novel strategies to overcome chemoresistance are desperately needed for improved treatment of human GBM. Recent studies have demonstrated that the tumor microenvironment plays a critical role in the chemoresistance of various tumor types, which makes it a suitable target in anti-cancer therapies, as well as a valuable biomarker for prognostic purposes. This review focuses on chemoresistance in GBM induced by stromal cells, including the endothelium of blood vessels, astrocytes, and myeloid cells, as well as non-cellular factors in the tumor microenvironment. Corresponding therapies are discussed, including progressive strategies involving 3-dimensional models integrating engineering as well as biological advances.

Survival Analysis of Glioblastoma Multiforme

Introduction:

To evaluate the survival of Glioblastoma Multiforme (GBM).

Material and Methods:

Patients with a pathological diagnosis of Glioblastoma Multiforme (GBM) between 1 January 1994 and 30 November 2013, were retrospectively reviewed. Inclusion criteria: 1) GBM patients with confirmed pathology, 2) GBM patients were treated by multimodality therapy. Exclusion criteria: 1) GBM patients with unconfirmed pathology, 2) GBM patients with spinal involvement, 3) GBM patients with incomplete data records. Seventy-seven patients were treated by multimodality therapy such as surgery plus post-operative radiotherapy (PORT), post-operative Temozolomide (TMZ) concurrent with radiotherapy (CCRT), post-operative CCRT with adjuvant TMZ. The overall survival was calculated by the Kaplan-Meier method and the log-rank test was used to compare the survival curves. A p-value of ≤ 0.05 was considered to be statistically significant.

Results:

Seventy-seven patients with a median age of 53 years (range 4-76 years) showed a median survival time (MST) of 12 months. In subgroup analyses, the PORT patients revealed a MST of 11 months and 2 year overall survival (OS) rates were 17.2%, the patients with post-operative CCRT with or without adjuvant TMZ revealed a MST of 23 months and 2 year OS rates were 38.2%. The MST of patients by Recursive Partitioning Analysis (RPA), classifications III, IV, V, VI were 26.8 months, 14.2 months, 9.9 months, and 4.0 months, (p <0.001).

Conclusions:

The MST of the patients who had post-operative CCRT with or without adjuvant TMZ was better than the PORT group. The RPA classification can be used to predict survival. Multimodality therapy demonstrated the most effective treatment outcome. Temozolomide might be beneficial for GBM patients in order to increase survival time.

Local strategies and delivery systems for the treatment of malignant gliomas

Glioma is one of the most common type of malignant tumours with high morbidity and mortality rates. Due to the particular features of the brain, such as blood-brain barrier or blood-tumour barrier, therapeutic agents are ineffective by systemic administration. The tumour inevitably recurs and devitalises patients. Herein, an overview of the localised gliomas treatment strategies is provided, including direct intratumoural/intracerebral injection, convection-enhanced delivery, and the implant of biodegradable polymer systems. The advantages and disadvantages of each therapy are discussed. Subsequently, we have reviewed the recent developments of therapeutic delivery systems aimed at transporting sufficient amounts of antineoplastic drugs into the brain tumour sites while minimising the potential side effects. To treat gliomas, localised and controlled delivery of drugs at their desired site of action is preferred as it reduces toxicity and increases treatment efficiency. Simultaneously, various drug delivery systems (DDS) have been used to enhance drug delivery to the brain. Use of non-conventional DDS for localised therapy has greatly expanded the spectrum of drugs available for the treatment of malignant tumours. Use smart DDS via localised delivery strategies, in combination with radiotherapy and multiple drug loading would serve as a promising approach to treat gliomas.

Enhanced proteasomal activity is essential for long term survival and recurrence of innately radiation resistant residual glioblastoma cells

Therapy resistance and recurrence in Glioblastoma is due to the presence of residual radiation resistant cells. However, because of their inaccessibility from patient biopsies, the molecular mechanisms driving their survival remain unexplored. Residual Radiation Resistant (RR) and Relapse (R) cells were captured using cellular radiation resistant model generated from patient derived primary cultures and cell lines. iTRAQ based quantitative proteomics was performed to identify pathways unique to RR cells followed by in vitro and in vivo experiments showing their role in radio-resistance. 2720 proteins were identified across Parent (P), RR and R population with 824 and 874 differential proteins in RR and R cells. Unsupervised clustering showed proteasome pathway as the most significantly deregulated pathway in RR cells. Concordantly, the RR cells displayed enhanced expression and activity of proteasome subunits, which triggered NFkB signalling. Pharmacological inhibition of proteasome activity led to impeded NFkB transcriptional activity, radio-sensitization of RR cells in vitro, and significantly reduced capacity to form orthotopic tumours in vivo. We demonstrate that combination of proteasome inhibitor with radio-therapy abolish the inaccessible residual resistant cells thereby preventing GBM recurrence. Furthermore, we identified first proteomic signature of RR cells that can be exploited for GBM therapeutics.

Comparative evaluation of anti-angiogenic effects of noscapine derivatives

Angiogenesis, the formation of new capillaries from pre-existing vessels, is essential for tumor progression. Synthetic derivatives of anti-cancer compound, noscapine (an opium alkaloid) such as Cl-noscapine, Br-noscapine and Folate-noscapine along with two of the reference compounds, TNP-470 and paclitaxel were examined for anti-angiogenic activities by using human umbilical vein endothelial cells (HUVECs). The noscapine derivatives showed anti-angiogenic activity albeit at high concentration compared to the reference compounds. All the tested compounds inhibited angiogenesis in a dose-dependent manner; the drug concentration causing 50% inhibition of cell survival was 11.87 μM for Cl-noscapine, 6.9 μM for Br-noscapine and 6.79 μM for folate-noscapine. Besides, all the noscapine derivatives significantly inhibited cord formation (IC50 for Cl-noscapine is 50.76 μM, for Br-noscapine is 90.08 μM and for folate-noscapine is 18.44 μM) as well as migration and invasion (IC50 value of Cl-noscapine is 28.01 μM, for Br-noscapine is 19.78 μM and for folate-noscapine is 10.76 μM) of endothelial cells. Based on these results, we speculated that the inhibitory effects on human endothelial cell proliferation of noscapine derivatives might be important for anti-angiogenesis.

IL13RA2 targeted alpha particle therapy against glioblastomas

Glioblastoma (GBM) is the most aggressive primary malignant brain cancer that invariably results in a dismal prognosis. Chemotherapy and radiotherapy have not been completely effective as standard treatment options for patients due to recurrent disease. We and others have therefore developed molecular strategies to specifically target interleukin 13 receptor alpha 2 (IL13RA2), a GBM restricted receptor expressed abundantly on over 75% of GBM patients. In this work, we evaluated the potential of Pep-1L, a novel IL13RA2 targeted peptide, as a platform to deliver targeted lethal therapies to GBM. To demonstrate GBM-specificity, we radiolabeled Pep-1L with Copper-64 and performed in vitro cell binding studies, which demonstrated specific binding that was blocked by unlabeled Pep-1L. Furthermore, we demonstrated real-time GBM localization of [⁶⁴Cu]Pep-1L to orthotopic GBMs using small animal PET imaging. Based on these targeting data, we performed an initial in vivo safety and therapeutic study using Pep-1L conjugated to Actinium-225, an alpha particle emitter that has been shown to potently and irreversibly kill targeted cells. We infused [²²⁵Ac]Pep-1L into orthotopic GBMs using convection-enhanced delivery and found no significant adverse events at injected doses. Furthermore, our initial data also demonstrated significantly greater overall, median and mean survival in treated mice when compared to those in control groups (p < 0.05). GBM tissue extracted from mice treated with [²²⁵Ac]Pep-1L showed double stranded DNA breaks, lower Ki67 expression and greater propidium iodide internalization, indicating anti-GBM therapeutic effects of [²²⁵Ac]Pep-1L. Based on our results, Pep-1L warrants further investigation as a potential targeted platform to deliver anti-cancer agents.

Hyaluronic Acid-Modified Micelles Encapsulating Gem-C12 and HNK for Glioblastoma Multiforme Chemotherapy

Glioblastoma multiforme (GBM), a prevalent brain cancer with high mortality, is resistant to the conventional single-agent chemotherapy. In this study, we employed a combination chemotherapy strategy to inhibit GBM growth and addressed its possible beneficial effects. The synergistic effect of lauroyl-gemcitabine (Gem-C₁₂) and honokiol (HNK) was first tested and optimized using U87 cells in vitro. Then, the hyaluronic acid-grafted micelles (HA-M), encapsulating the optimal mole ratio (1:1) of Gem-C₁₂ and HNK, were prepared and characterized. Cell-based studies demonstrated that HA-M could be transported into cells by a CD44 receptor-mediated endocytosis, which could penetrate deeper into tumor spheroids and enhance the cytotoxicity of payloads to glioma cells. In vivo, drug-loaded HA-M significantly increased the survival rate of mice bearing orthotopic xenograft GBM compared with the negative control (1.85-fold). Immunohistochemical analysis indicated that the enhanced efficacy of HA-M was attributed to the stronger inhibition of glioma proliferation and induction of apoptosis. Altogether, our findings showed advantages of combination chemotherapy of GBM using HA-grafted micelles.

Use of Nanoparticles for Cerebral Cancer

Nanoparticles made of poly(butyl cyanoacrylate) (PBCA) or poly(lactic-co-glycolic acid) (PLGA) coated with polysorbate 80 or poloxamer 188 enable the transport of cytostatics such as doxorubicin across the blood-brain barrier (BBB). Following intravenous injection to rats bearing intracranially the very aggressive glioblastoma 101/8 these particles loaded with doxorubicin significantly increased the survival times and led to a complete tumor remission in 20–40% of the animals. Moreover, these particles considerably reduced the dose-limiting cardiotoxicity and also the testicular toxicity of this drug. The drug transport across the BBB by nanoparticles appears to be due to a receptor-mediated interaction with the brain capillary endothelial cells, which is facilitated by certain plasma apolipoproteins adsorbed by nanoparticles in the blood.

Anti-SEMA3A Antibody: A Novel Therapeutic Agent to Suppress Glioblastoma Tumor Growth

Purpose

Glioblastoma (GBM) is classified as one of the most aggressive and lethal brain tumor. Great strides have been made in understanding the genomic and molecular underpinnings of GBM, which translated into development of new therapeutic approaches to combat such deadly disease. However, there are only few therapeutic agents that can effectively inhibit GBM invasion in a clinical framework. In an effort to address such challenges, we have generated anti-SEMA3A monoclonal antibody as a potential therapeutic antibody against GBM progression.

Materials and Methods

We employed public glioma datasets, Repository of Molecular Brain Neoplasia Data and The Cancer Genome Atlas, to analyze SEMA3AmRNA expression in human GBM specimens. We also evaluated for protein expression level of SEMA3A via tissue microarray (TMA) analysis. Cell migration and proliferation kinetics were assessed in various GBM patient-derived cells (PDCs) and U87-MG cell-line for SEMA3A antibody efficacy. GBM patient-derived xenograft (PDX) models were generated to evaluate tumor inhibitory effect of anti-SEMA3A antibody in vivo.

Results

By combining bioinformatics and TMA analysis, we discovered that SEMA3A is highly expressed in human GBM specimens compared to non-neoplastic tissues. We developed three different anti-SEMA3A antibodies, in fully human IgG form, through screening phage-displayed synthetic antibody library using a classical panning method. Neutralization of SEMA3A significantly reduced migration and proliferation capabilities of PDCs and U87-MG cell line in vitro. In PDX models, treatment with anti-SEMA3A antibody exhibited notable tumor inhibitory effect through down-regulation of cellular proliferative kinetics and tumor-associated macrophages recruitment.

Conclusion

In present study, we demonstrated tumor inhibitory effect of SEMA3A antibody in GBM progression and present its potential relevance as a therapeutic agent in a clinical framework.

Ependymal enhancement on magnetic resonance imaging for the identification of high-grade gliomas

BACKGROUND

High-grade gliomas have high infiltrative potential and spread along white matter and blood vessels. Enhancement of ependymal lining on magnetic resonance imaging (MRI) is considered as a marker of parenchymal spread of disease. In this study, we aimed to assess the sensitivity, specificity, and positive and negative predictive values of ependymal enhancement (EE) for identification of high-grade glial tumors.

METHODS

We reviewed preoperative MRI scans of 94 consecutive patients surgically treated for space occupying lesions of the brain for EE. Assessment for EE was blind to the final histopathological diagnosis of the patient. An enhancement of more than 2 mm was considered positive. Pathologies of these patients were reviewed and matched to the radiological findings. Percentage and proportion of EE in glial and non-glial pathology groups was then calculated and a sensitivity and specificity analysis was performed.

RESULTS

The population included 94 cases (64 males and 30 females) with population mean age 45 ± 15.5 years. Sensitivity of EE in differentiating glioma from total number of cases was 82.61% specificity 35.42% (P value = 0.048). EE had a sensitivity of 67.39% and specificity of 64.58% (P value = 0.002) in identifying high-grade glioma within the glioma group with a positive predictive value of 64.58% (95% CI: 49.46% to 77.83%), negative predictive value of 67.39% (95% CI: 51.98% to 80.46%).

CONCLUSION

EE has moderate sensitivity and specificity for high-grade gliomas. However, larger sample studies are required for further validation of this observations.

High expression of PCBP2 is associated with progression and poor prognosis in patients with glioblastoma

BACKGROUND

Poly(C)-binding protein 2 (PCBP2) has been found to have ambiguous functions in a variety of cancers. However, the specific biological function of PCBP2 and its mechanism in glioblastoma remain unclear. We investigated the expression of PCBP2 in 143 glioblastoma specimens to explore the linkage between PCBP2 expression and clinicopathological parameters as well as clinical significance. Furthermore, the underlying mechanisms of PCBP2 on glioblastoma progression were discussed in vitro.

METHODS

The transcriptional and translational levels of PCBP2 in 143 glioblastoma patients were detected by quantitative Real-time PCR (qRT-PCR) and western blot. The association of prognostic outcomes and PCBP2 expression was evaluated using Kaplan-Meier analysis.

RESULTS

PCBP2 expression was markedly increased in higher stages of glioblastoma compared with those in lower stages (P<0.001). High expression of PCBP2 was associated with higher clinical stage and histological grade (P<0.001). Further research suggested that PCBP2 upregulation was connected with poorer prognosis in patients with glioblastoma (P<0.001). Moreover, PCBP2 knockdown could significantly decreased the colony formation and invasion capability of glioblastoma cells (P<0.01). Conversely, PCBP2 overexpression could increase the colony formation and invasion capability (P<0.01).

CONCLUSION

These findings indicated that PCBP2 might be a novel prognostic biomarker and a potential therapeutic target of glioblastoma.

PHLPPing through history: a decade in the life of PHLPP phosphatases

In the decade since their discovery, the PH domain leucine-rich repeat protein phosphatases (PHLPP) have emerged as critical regulators of cellular homeostasis, and their dysregulation is associated with various pathophysiologies, ranging from cancer to degenerative diseases, such as diabetes and heart disease. The two PHLPP isozymes, PHLPP1 and PHLPP2, were identified in a search for phosphatases that dephosphorylate Akt, and thus suppress growth factor signaling. However, given that there are over 200 000 phosphorylated residues in a single cell, and fewer than 50 Ser/Thr protein phosphatases, it is not surprising that PHLPP has many other cellular functions yet to be discovered, including a recently identified role in regulating the epigenome. Both PHLPP1 and PHLPP2 are commonly deleted in human cancers, supporting a tumor suppressive role. Conversely, the levels of one isozyme, PHLPP1, are elevated in diabetes. Thus, mechanisms to correctly control PHLPP activity in cells are critical for normal cellular homeostasis. This review summarizes the known functions of PHLPP and its role in disease.

Peptide grafted and self-assembled poly(γ-glutamic acid)-phenylalanine nanoparticles targeting camptothecin to glioma

Aim: To synthesize cRGDfK peptide conjugated poly(γ-glutamic acid)-phenylalanine nanoparticles to improve the therapeutic efficacy of camptothecin (CPT) against glioblastoma multiforme. Methods: Peptide-conjugated, drug-loaded nanoparticles (cRGDfK-conjugated camptothecin-loaded PGA–PA nanoparticles [RCPN]) were prepared and physico-chemically characterized using different techniques. Nanoparticles were evaluated for in vitro anticancer activity, cellular uptake, induction of apoptosis and wound healing cell migration against U87MG human glioblastoma cells. Results: RCPN, with a particle size of <100 nm and 65% CPT encapsulation efficiency, exhibited a dose- and time-dependent cytotoxicity to glioblastoma cells. Compared with native CPT or unconjugated nanoparticles, RCPN induced apoptosis, increased reactive oxygen species generation and inhibited U87MG cell migration. Conclusion: cRGDfK-mediated and amphiphilic copolymer-based nanomedicines represent a new approach for improved delivery of anticancer drugs to and treatment of glioblastoma multiforme.

Alpha Particle Enhanced Blood Brain/Tumor Barrier Permeabilization in Glioblastomas Using Integrin Alpha-v Beta-3-Targeted Liposomes

Glioblastoma (GBM) is the most common primary malignant astrocytoma characterized by extensive invasion, angiogenesis, hypoxia, and micrometastasis. Despite the relatively leaky nature of GBM blood vessels, effective delivery of antitumor therapeutics has been a major challenge due to the complications caused by the blood-brain barrier (BBB) and the highly torturous nature of newly formed tumor vasculature (blood tumor barrier-BTB). External beam radiotherapy was previously shown to be an effective means of permeabilizing central nervous system (CNS) barriers. By using targeted short-ranged radionuclides, we show for the first time that our targeted actinium-225-labeled α_vβ₃-specific liposomes (²²⁵Ac-IA-TLs) caused catastrophic double stranded DNA breaks and significantly enhanced the permeability of BBB and BTB in mice bearing orthotopic GBMs. Histologic studies revealed characteristic α-particle induced double strand breaks within tumors but was not significantly present in normal brain regions away from the tumor where BBB permeability was observed. These findings indicate that the enhanced vascular permeability in these distal regions did not result from direct α-particle-induced DNA damage. On the basis of these results, in addition to their direct antitumor effects, ²²⁵Ac-IA-TLs can potentially be used to enhance the permeability of BBB and BTB for effective delivery of systemically administered antitumor therapeutics. Mol Cancer Ther; 16(10); 2191-200. ©2017 AACR.

Notch3 signaling-mediated melanoma-endothelial crosstalk regulates melanoma stem-like cell homeostasis and niche morphogenesis

Melanoma is among the most virulent cancers, owing to its propensity to metastasize and its resistance to current therapies. The treatment failure is largely attributed to tumor heterogeneity, particularly subpopulations possessing stem cell-like properties, ie, melanoma stem-like cells (MSLCs). Evidence indicates that the MSLC phenotype is malleable and may be acquired by non-MSLCs through phenotypic switching upon appropriate stimuli, the so-called 'dynamic stemness'. Since the phenotypic characteristics and functional integrity of MSLCs depend on their vascular niche, using a two-dimensional (2D) melanoma-endothelium co-culture model, where the MSLC niche is recapitulated in vitro, we identified Notch3 signaling pathway as a micro-environmental cue governing MSLC phenotypic plasticity via pathway-specific gene expression arrays. Accordingly, lentiviral shRNA-mediated Notch3 knockdown (KD) in melanoma cell lines exhibiting high levels of endogenous Notch3 led to retarded/abolished tumorigenicity in vivo through both depleting MSLC fractions, evinced by MSLC marker downregulation (eg, CD133 and CD271); and impeding the MSLC niche, corroborated by the attenuated tumor angiogenesis as well as vasculogenic mimicry. In contrast, Notch3 KD affected neither tumor growth nor MSLC subsets in a melanoma cell line with relatively low endogenous Notch3 expression. Thus, Notch3 signaling may facilitate MSLC plasticity and niche morphogenesis in a cell context-dependent manner. Our findings illustrate Notch3 as a molecular switch driving melanoma heterogeneity, and provide the biological rationale for Notch inhibition as a promising therapeutic option.

Suppression of p53-inducible gene 3 is significant for glioblastoma progression and predicts poor patient prognosis

Glioblastoma is the most malignant and invasive brain tumor with extremely poor prognosis. p53-inducible gene 3, a downstream molecule of the tumor suppressor p53, has been found involved in apoptosis and oxidative stress response. However, the functions of p53-inducible gene 3(PIG3) in cancer are far from clear including glioblastoma. In this study, we found that p53-inducible gene 3 expression was suppressed in glioblastoma tissues compared with normal tissues. And the expression of p53-inducible gene 3 was significantly associated with the World Health Organization grade. Patients with high p53-inducible gene 3 expression have a significantly longer median survival time (15 months) than those with low p53-inducible gene 3 expression (8 months). According to Cox regression analysis, p53-inducible gene 3 was an independent prognostic factor with multivariate hazard ratio of 0.578 (95% confidence interval, 0.352-0.947; p = 0.030) for overall survival. Additionally, gain and loss of function experiments showed that knockdown of p53-inducible gene 3 significantly increased the proliferation and invasion ability of glioblastoma cells while overexpression of p53-inducible gene 3 inhibited the proliferation and invasion ability. The results of in vivo glioblastoma models further confirmed that p53-inducible gene 3 suppression promoted glioblastoma progression. Altogether, our data suggest that high expression of p53-inducible gene 3 is significant for glioblastoma inhibition and p53-inducible gene 3 independently indicates good prognosis in patients, which might be a novel prognostic biomarker or potential therapeutic target in glioblastoma.

Overexpression of FoxO3a is associated with glioblastoma progression and predicts poor patient prognosis

Forkhead transcription factor FoxO3a has been reported to have ambiguous functions and distinct mechanisms in various solid tumors, including glioblastoma (GBM). Although a preliminary analysis of a small sample of patients indicated that FoxO3a aberrations in glioma might be related to aggressive clinical behavior, the clinical significance of FoxO3a in glioblastoma remains unclear. We investigated the expression of FoxO3a in a cohort of 91 glioblastoma specimens and analyzed the correlations of protein expression with patient prognosis. Furthermore, the functional impact of FoxO3a on GBM progression and the underlying mechanisms of FoxO3a regulation were explored in a series of in vitro and in vivo assays. FoxO3a expression was elevated in glioblastoma tissues, and high nuclear FoxO3a expression in human GBM tissues was associated with poor prognosis. Moreover, knockdown of FoxO3a significantly reduced the colony formation and invasion ability of GBM cells, whereas overexpression of FoxO3a promoted the colony formation and invasion ability. The results of in vivo GBM models further confirmed that FoxO3a knockdown inhibited GBM progression. More, the pro-oncogenic effects of FoxO3a in GBM were mediated by the activation of c-Myc, microtubule-associated protein 1 light chain 3 beta (LC3B) and Beclin1 in a mixed-lineage leukemia 2 (MLL2)-dependent manner. These findings suggest that high FoxO3a expression is associated with glioblastoma progression and that FoxO3a independently indicates poor prognosis in patients. FoxO3a might be a novel prognostic biomarker or a potential therapeutic target in glioblastoma.

Targeted concurrent and sequential delivery of chemotherapeutic and antiangiogenic agents to the brain by using drug-loaded nanofibrous membranes

Glioblastoma is the most frequent and devastating primary brain tumor. Surgery followed by radiotherapy with concomitant and adjuvant chemotherapy is the standard of care for patients with glioblastoma. Chemotherapy is ineffective, because of the low therapeutic levels of pharmaceuticals in tumor tissues and the well-known tumor-cell resistance to chemotherapy. Therefore, we developed bilayered poly(d,l)-lactide-co-glycolide nanofibrous membranes that enabled the sequential and sustained release of chemotherapeutic and antiangiogenic agents by employing an electrospinning technique. The release characteristics of embedded drugs were determined by employing an in vitro elution technique and high-performance liquid chromatography. The experimental results showed that the fabricated nanofibers showed a sequential drug-eluting behavior, with the release of high drug levels of chemotherapeutic carmustine, irinotecan, and cisplatin from day 3, followed by the release of high concentrations of the antiangiogenic combretastatin from day 21. Biodegradable multidrug-eluting nanofibrous membranes were then dispersed into the cerebral cavity of rats by craniectomy, and the in vivo release characteristics of the pharmaceuticals from the membranes were investigated. The results suggested that the nanofibrous membranes released high concentrations of pharmaceuticals for more than 8 weeks in the cerebral parenchyma of rats. The result of histological analysis demonstrated developmental atrophy of brains with no inflammation. Biodegradable nanofibrous membranes can be manufactured for long-term sequential transport of different chemotherapeutic and anti-angiogenic agents in the brain, which can potentially improve the treatment of glioblastoma multiforme and prevent toxic effects due to systemic administration.

Optimized creation of glioblastoma patient derived xenografts for use in preclinical studies

BACKGROUND

Glioblastoma multiforme (GBM) is the most common and lethal brain tumor in adults, highlighting the need for novel treatment strategies. Patient derived xenografts (PDX) represent a valuable tool to accomplish this task.

METHODS

PDX were established by implanting GBM tissue subcutaneously. Engraftment success was compared between NMRI Foxn1nu and NOD/SCID as well as between fresh and cryopreserved tissue. Established PDX were analyzed histologically and molecularly. Five PDX were experimentally treated with different drugs to assess their potential for preclinical drug testing.

RESULTS

Establishment of PDX was attempted for 36 consecutive GBM cases with an overall success rate of 22.2% in NMRI Foxn1nu mice. No difference was observed between fresh or cryopreserved (20-1057 days) tissue in direct comparison (n = 10 cases). Additionally, engraftment was better in NOD/SCID mice (38.8%) directly compared to NMRI Foxn1nu mice (27.7%) (n = 18 cases). Molecular data and histology of the PDX compare well to the primary GBM. The experimental treatment revealed individual differences in the sensitivity towards several clinically relevant drugs.

CONCLUSIONS

The use of vitally frozen GBM tissue allows a more convenient workflow without efficiency loss. NOD/SCID mice appear to be better suited for initial engraftment of tumor tissue compared to NMRI Foxn1nu mice.

Apoptin Gene Delivery by the Functionalized Polyamidoamine Dendrimer Derivatives Induces Cell Death of U87-MG Glioblastoma Cells

Malignant glioma is the most common and aggressive form of primary brain tumor in adults. In this study, we describe the efficacy of nonviral gene delivery carriers, histidine- and arginine- or histidine- and lysine-grafted polyamidoamine (PAMAM) dendrimers (PAMAM-H-R and PAMAM-H-K), in delivering a therapeutic and a tumor-selective killer gene, apoptin, using human glioma cells (U87-MG) and newborn human dermal fibroblast cells. We analyzed transfection efficiency using luciferase and a plasmid DNA encoding for enhanced green fluorescent protein and assessed cell viability in both cells. The results show that transfection efficiency of PAMAM-H-R and PAMAM-H-K was greatly increased compared with that of native PAMAM. Moreover, among PAMAM derivatives, cytotoxicity of PAMAM-H-K was very low. We treated both cells with complexes of PAMAM-H-R or PAMAM-H-K and apoptin and analyzed their cellular uptake by flow cytometry and localization by confocal microscopy. Furthermore, cell cycle distribution, caspase 3 activity assay, and JC-1 analysis showed cell death induced by apoptin in U87-MG cells. The present study demonstrates that a PAMAM-H-R/apoptin complex is an effective gene carrier system in glioma cell culture.

Glioblastoma Multiforme: A Review of its Epidemiology and Pathogenesis through Clinical Presentation and Treatment

Glioblastoma multiforme (GBM) is one of the most malignant types of central nervous system tumors. Despite advances in treatment modalities it remains largely incurable. The objective of our review is to provide a holistic picture of GBM epidemiology, etiology, pathogenesis, clinical findings and treatment. A literature search was conducted for GBM at PubMed and Google Scholar, with relevant key words like glioblastoma multiforme, pathogenesis, signs and symptoms, treatment etc., and papers published until 2015 were reviewed. It was found that radiation and certain genetic syndromes are the only risk factors identified to date for GBM. Depending on the tumor site patients may present to the clinic with varying symptoms. To confirm the presence and the extent of tumor, various invasive and non-invasive imaging techniques require employment. The literature survey revealed the pathogenesis to involve aberrations of multiple signaling pathways through multiple genetic mutations and altered gene expression. Although several treatment options are available, including surgery, along with adjuvant chemo- and radio-therapy, the disease has a poor prognosis and patients generally succumb within 14 months of diagnosis.

Dendritic cell immunotherapy versus bevacizumab plus irinotecan in recurrent malignant glioma patients: a survival gain analysis

BACKGROUND

The bevacizumab and irinotecan protocol is considered a standard treatment regimen for recurrent malignant glioma. Recent advances in immunotherapy have hinted that vaccination with dendritic cells could become an alternative salvage therapy for the treatment of recurrent malignant glioma.

METHODS

A search was performed on PubMed, Cochrane Library, Web of Science, ScienceDirect, and Embase in order to identify studies with patients receiving bevacizumab plus irinotecan or dendritic cell therapy for recurrent malignant gliomas. The data obtained from these studies were used to perform a systematic review and survival gain analysis.

RESULTS

Fourteen clinical studies with patients receiving either bevacizumab plus irinotecan or dendritic cell vaccination were identified. Seven studies followed patients that received bevacizumab plus irinotecan (302 patients) and seven studies included patients that received dendritic cell immunotherapy (80 patients). For the patients who received bevacizumab plus irinotecan, the mean reported median overall survival was 7.5 (95% confidence interval [CI] 4.84-10.16) months. For the patients who received dendritic cell immunotherapy, the mean reported median overall survival was 17.9 (95% CI 11.34-24.46) months. For irinotecan + bevacizumab group, the mean survival gain was -0.02±2.00, while that for the dendritic cell immunotherapy group was -0.01±4.54.

CONCLUSION

For patients with recurrent malignant gliomas, dendritic cell immunotherapy treatment does not have a significantly different effect when compared with bevacizumab and irinotecan in terms of survival gain (P=0.535) and does not improve weighted survival gain (P=0.620).

Multimodality imaging and mathematical modelling of drug delivery to glioblastomas

Patients diagnosed with glioblastoma, an aggressive brain tumour, have a poor prognosis, with a median overall survival of less than 15 months. Vasculature within these tumours is typically abnormal, with increased tortuosity, dilation and disorganization, and they typically exhibit a disrupted blood-brain barrier (BBB). Although it has been hypothesized that the 'normalization' of the vasculature resulting from anti-angiogenic therapies could improve drug delivery through improved blood flow, there is also evidence that suggests that the restoration of BBB integrity might limit the delivery of therapeutic agents and hence their effectiveness. In this paper, we apply mathematical models of blood flow, vascular permeability and diffusion within the tumour microenvironment to investigate the effect of these competing factors on drug delivery. Preliminary results from the modelling indicate that all three physiological parameters investigated-flow rate, vessel permeability and tissue diffusion coefficient-interact nonlinearly to produce the observed average drug concentration in the microenvironment.

FK228 augmented temozolomide sensitivity in human glioma cells by blocking PI3K/AKT/mTOR signal pathways

Temozolomide is a novel cytotoxic agent currently used as first-line chemotherapy for glioblastoma multiforme (GBM). Romidepsin (FK228), a histone deacetylase inhibitor, is a promising new class of antineoplastic agent with the capacity to induce growth arrest and/or apoptosis of cancer cells. However, combination of the two drugs in glioma remains largely unknown. In the present study, we evaluated the combinatory effects of FK228 with TMZ in glioma, and its molecular mechanisms responsible for these effects. Glioma cell lines were treated with TMZ, FK228 or the combination of drugs. The resistance effect including cytotoxicity and apoptosis was determined in glioma cells, respectively. We further evaluated the effects of FK228 in the PI3K/Akt-signaling pathway in vitro. Mice engrafted with 5×10⁶ LN382 cells were treated with TMZ, FK228 or the combination of two drugs, and tumor weights and volumes were measured, respectively. FK228 enhanced the cytotoxic effects of TMZ in glioma cells compared to vehicle-treated controls or each drug alone. The combination of FK228 and TMZ-induced apoptosis was demonstrated by increased expression of cleaved-Caspase 3, Bax, cleaved-PARP, and decreased Bcl-2 expression. Furthermore, the expression of key components of the PI3K/Akt-signaling pathway showed that combination of FK228 and TMZ block PI3K/Akt pathways in vitro. This block effect was also confirmed in vivo in mice models. Mice treated with both FK228 and TMZ drugs showed significantly reduced tumor weights and volumes, compared to each drug alone. Our results suggested that FK228 augmented temozolomide sensitivity in human glioma cells partially by blocking PI3K/AKT/mTOR signal pathways. It thus may provide a promising target for improving the therapeutic outcome of TMZ-resistant gliomas, although further studies will be needed.