Glioblastoma multiforme: Pathogenesis and treatment

Glioblastoma: Pathogenesis and Current Status of Chemotherapy and Other Novel Treatments

Glioblastoma is one of the most common and detrimental forms of solid brain tumor, with over 10,000 new cases reported every year in the United States. Despite aggressive multimodal treatment approaches, the overall survival period is reported to be less than 15 months after diagnosis. A widely used approach for the treatment of glioblastoma is surgical removal of the tumor, followed by radiotherapy and chemotherapy. While there are several drugs available that are approved by the Food and Drug Administration (FDA), significant efforts have been made in recent years to develop new chemotherapeutic agents for the treatment of glioblastoma. This review describes the molecular targets and pathogenesis as well as the current progress in chemotherapeutic development and other novel therapies in the clinical setting for the treatment of glioblastoma.

A Novel Highly Selective Cannabinoid CB2 Agonist Reduces in vitro Growth and TGF-beta Release of Human Glial Cell Tumors

BACKGROUND

Cannabinoid receptors have been detected in human gliomas and cannabinoids have been proposed as novel drug candidates in the treatment of brain tumors.

AIMS

To test the in vitro antitumor activity of COR167, a novel cannabinoid CB2-selective agonist displaying a high binding affinity for human CB2 receptors, on tumor cells isolated from human glioblastoma multiforme and anaplastic astrocytoma.

METHODS

Glioma cell cultures were established from two glioblastoma multiforme and two anaplastic astrocytomas. Proliferation was measured in the presence or absence of COR167 with a bromodeoxyuridine (BrdU) cell proliferation ELISA assay. CB2 receptor expression was detected by western blotting. Apoptosis was assessed with phycoerythrin (PE) annexin V flow cytometry kit. TGF-beta 1 and 2 levels were analyzed in culture supernatants with commercial ELISAs.

RESULTS

COR167 was found to significantly reduce the proliferation of both glioblastoma and anaplastic astrocytoma in a dose-dependent manner at lower doses than other known, less specific CB2 agonists. This activity is independent of apoptosis and is associated with a significant reduction of TGF-beta 1 and 2 levels in supernatants of glioma cell cultures.

CONCLUSION

These findings add to the role of cannabinoid CB2 receptor as a possible pharmacological target to counteract glial tumor growth and encourage further work to explore any other pharmacological effect of this novel CB2 agonist useful in the treatment of human gliomas.

Spider venom administration impairs glioblastoma growth and modulates immune response in a non-clinical model

Molecules from animal venoms are promising candidates for the development of new drugs. Previous in vitro studies have shown that the venom of the spider Phoneutria nigriventer (PnV) is a potential source of antineoplastic components with activity in glioblastoma (GB) cell lines. In the present work, the effects of PnV on tumor development were established in vivo using a xenogeneic model. Human GB (NG97, the most responsive line in the previous study) cells were inoculated (s.c.) on the back of RAG^−/− mice. PnV (100 µg/Kg) was administrated every 48 h (i.p.) for 14 days and several endpoints were evaluated: tumor growth and metabolism (by microPET/CT, using ¹⁸F-FDG), tumor weight and volume, histopathology, blood analysis, percentage and profile of macrophages, neutrophils and NK cells isolated from the spleen (by flow cytometry) and the presence of macrophages (Iba-1 positive) within/surrounding the tumor. The effect of venom was also evaluated on macrophages in vitro. Tumors from PnV-treated animals were smaller and did not uptake detectable amounts of ¹⁸F-FDG, compared to control (untreated). PnV-tumor was necrotic, lacking the histopathological characteristics typical of GB. Since in classic chemotherapies it is observed a decrease in immune response, methotrexate (MTX) was used only to compare the PnV effects on innate immune cells with a highly immunosuppressive antineoplastic drug. The venom increased monocytes, neutrophils and NK cells, and this effect was the opposite of that observed in the animals treated with MTX. PnV increased the number of macrophages in the tumor, while did not increase in the spleen, suggesting that PnV-activated macrophages were led preferentially to the tumor. Macrophages were activated in vitro by the venom, becoming more phagocytic; these results confirm that this cell is a target of PnV components. Spleen and in vitro PnV-activated macrophages were different of M1, since they did not produce pro- and anti-inflammatory cytokines. Studies in progress are selecting the venom molecules with antitumor and immunomodulatory effects and trying to better understand their mechanisms. The identification, optimization and synthesis of antineoplastic drugs from PnV molecules may lead to a new multitarget chemotherapy. Glioblastoma is associated with high morbidity and mortality; therefore, research to develop new treatments has great social relevance. Natural products and their derivatives represent over one-third of all new molecular entities approved by FDA. However, arthropod venoms are underexploited, although they are a rich source of new molecules. A recent in vitro screening of the Phoneutria nigriventer spider venom (PnV) antitumor effects by our group has shown that the venom significantly affected glioblastoma cell lines. Therefore, it would be relevant to establish the effects of PnV on tumor development in vivo, considering the complex neoplastic microenvironment. The venom was effective at impairing tumor development in murine xenogeneic model, activating the innate immune response and increasing tumor infiltrating macrophages. In addition, PnV activated macrophages in vitro for a different profile of M1. These activated PnV-macrophages have potential to fight the tumor without promoting tumorigenesis. Studies in progress are selecting the venom molecules with antitumor and immunomodulatory effects and trying to better understand their mechanisms. We aim to synthesize and carry out a formulation with these antineoplastic molecules for clinical trials. Spider venom biomolecules induced smaller and necrotic xenogeneic GB; spider venom activated the innate immune system; venom increased blood monocytes and the migration of macrophages to the tumor; activated PnV-macrophages have a profile different of M1 and have a potential to fight the tumor without promote tumorigenesis.

Delivery across the blood-brain barrier: nanomedicine for glioblastoma multiforme

The malignant brain cancer, glioblastoma multiforme (GBM), is heterogeneous, infiltrative, and associated with chemo- and radioresistance. Despite pharmacological advances, prognosis is poor. Delivery into the brain is hampered by the blood-brain barrier (BBB), which limits the efficacy of both conventional and novel therapies at the target site. Current treatments for GBM remain palliative rather than curative; therefore, innovative delivery strategies are required and nanoparticles (NPs) are at the forefront of future solutions. Since the FDA approval of Doxil® (1995) and Abraxane (2005), the first generation of nanomedicines, development of nano-based therapies as anti-cancer treatments has escalated. A new generation of NPs has been investigated to efficiently deliver therapeutic agents to the brain, overcoming the restrictive properties of the BBB. This review discusses obstacles encountered with systemic administration along with integration of NPs incorporated with conventional and emerging treatments. Barriers to brain drug delivery, NP transport mechanisms across the BBB, effect of opsonisation on NPs administered systemically, and peptides as NP systems are addressed.

Hierarchical Cluster and Region of Interest Analyses Based on Mass Spectrometry Imaging of Human Brain Tumours

Imaging mass spectrometry (IMS) has been rarely used to examine specimens of human brain tumours. In the current study, high quality brain tumour samples were selected by tissue observation. Further, IMS analysis was combined with a new hierarchical cluster analysis (IMS-HCA) and region of interest analysis (IMS-ROI). IMS-HCA was successful in creating groups consisting of similar signal distribution images of glial fibrillary acidic protein (GFAP) and related multiple proteins in primary brain tumours. This clustering data suggested the relation of GFAP and these identified proteins in the brain tumorigenesis. Also, high levels of histone proteins, haemoglobin subunit α, tubulins, and GFAP were identified in a metastatic brain tumour using IMS-ROI. Our results show that IMS-HCA and IMS-ROI are promising techniques for identifying biomarkers using brain tumour samples.

HSP70/IL-2 Treated NK Cells Effectively Cross the Blood Brain Barrier and Target Tumor Cells in a Rat Model of Induced Glioblastoma Multiforme (GBM)

Natural killer (NK) cell therapy is one of the most promising treatments for Glioblastoma Multiforme (GBM). However, this emerging technology is limited by the availability of sufficient numbers of fully functional cells. Here, we investigated the efficacy of NK cells that were expanded and treated by interleukin-2 (IL-2) and heat shock protein 70 (HSP70), both in vitro and in vivo. Proliferation and cytotoxicity assays were used to assess the functionality of NK cells in vitro, after which treated and naïve NK cells were administrated intracranially and systemically to compare the potential antitumor activities in our in vivo rat GBM models. In vitro assays provided strong evidence of NK cell efficacy against C6 tumor cells. In vivo tracking of NK cells showed efficient homing around and within the tumor site. Furthermore, significant amelioration of the tumor in rats treated with HSP70/Il-2-treated NK cells as compared to those subjected to nontreated NK cells, as confirmed by MRI, proved the efficacy of adoptive NK cell therapy. Moreover, results obtained with systemic injection confirmed migration of activated NK cells over the blood brain barrier and subsequent targeting of GBM tumor cells. Our data suggest that administration of HSP70/Il-2-treated NK cells may be a promising therapeutic approach to be considered in the treatment of GBM.

Exosomal noncoding RNAs in Glioma: biological functions and potential clinical applications

Gliomas are complex and heterogeneous brain tumors with poor prognosis. Glioma cells can communicate with their surroundings to create a tumor-permissive microenvironment. Exosomes represent a new means of intercellular communication by delivering various bioactive molecules, including proteins, lipids and nucleic acids, and participate in tumor initiation and progression. Noncoding RNAs (ncRNAs) including microRNA, long-noncoding RNA, and circular RNA, account for a large portion of human transcriptome and play important roles in various pathophysiological processes, especially in cancers. In addition, ncRNAs can be selectively packaged, secreted and transferred between cells in exosomes and modulate numerous hallmarks of glioma, such as proliferation, invasion, angiogenesis, immune-escape, and treatment resistance. Hence, the strategies of specifically targeting exosomal ncRNAs could be attractive therapeutic options. Exosomes are able to cross the blood brain barrier (BBB), and are readily accessible in nearly all types of human biofluids, which make them the promising biomarkers for gliomas. Additionally, given the biocompatibility of exosomes, they can be engineered to deliver therapeutic factors, such as RNA, proteins and drugs, to target cells for therapeutic applications. Here, we reviewed current research on the roles of exosomal ncRNAs in glioma progression. We also discussed their potential clinical applications as novel biomarkers and therapeutics.

High Interobserver Agreement in the Subjective Classification of 5-Aminolevulinic Acid Fluorescence Levels in Newly Diagnosed Glioblastomas

BACKGROUND AND OBJECTIVES

Fluorescence-guided resection of glioblastomas (GBM) using 5-aminolevulinic acid (5-ALA) improves intraoperative tumor visualization and is thus widely used nowadays. During resection, different fluorescence levels can usually be distinguished within the same tumor. Recently, we demonstrated that strong, vague, and no fluorescence correspond to distinct histopathological characteristics in newly diagnosed GBM. However, the qualitative fluorescence classification by the neurosurgeon is subjective and currently no comprehensive data on interobserver variability is available. The aim of this study was thus to investigate the interobserver variability in the classification of 5-ALA fluorescence levels in newly diagnosed GBM.

STUDY DESIGN/MATERIALS AND METHODS

A questionnaire investigating the interobserver variability in 5-ALA fluorescence quantification was performed at a nation-wide neurosurgical oncology meeting. The participants involved in the neurosurgical/neurooncological field were asked to categorize 30 cases of 5-ALA fluorescence images derived from GBM resection on a lecture hall screen according to the widely used three-tier fluorescence classification scheme (negative, vague, or strong fluorescence). Additionally, participants were asked for information on their medical background such as specialty, level of training, and experience with 5-ALA fluorescence-guided procedures. Interobserver agreement was defined as the calculated mean κ values for each observer.

RESULTS

A total of 36 questionnaires were included in the final analysis. The mean average κ value in fluorescence classification within the entire cohort was 0.71 ± 0.12 and 29 (81%) participants had a substantial or almost perfect interobserver agreement (κ values 0.6-1.0). Interobserver agreement was significantly higher in neurosurgeons (mean κ: 0.83) as compared with non-neurosurgeons involved in the neurooncological field (mean κ: 0.52; P < 0.001). Furthermore, interobserver agreement was significantly higher in participants who had experience with at least 25 5-ALA fluorescence-guided surgeries (mean κ: 0.87) compared with less experienced colleagues (mean κ: 0.82; P = 0.039).

CONCLUSION

Our study found a high interobserver agreement in the qualitative classification of different 5-ALA fluorescence levels in newly diagnosed GBM. Interobserver agreement increases significantly in more experienced participants and therefore a high level of experience is crucial for reliable intraoperative fluorescence classification. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

Effects of progesterone on the cell number of gliomaspheres derived from human glioblastoma cell lines

AIMS

The malignancy of the Glioblastomas (GBM), the most frequent and aggressive brain tumors, have been associated with the presence of glioma stem cells (GSCs) which can form gliomaspheres (GS) in vitro. Progesterone (P) increases the proliferation, migration, and invasion of GBM cell lines through the interaction with its intracellular receptor (PR). However, it is unknown if the PR is expressed and the possible effects of P in the formation/differentiation of GS.

MAIN METHODS

GS were grown from U251 and U87 cell lines by selective culture with serum-free neural stem cell medium. GSCs were identified by the detection of Sox2, Ki67, Nestin, CD133, and CD15 by immunofluorescence. Additionally, the relative expression of PROM1, NES, SOX2, OLIG2, EZH2, BMI1 and PR genes was evaluated by RT-qPCR. The GS were treated with P, and the number of cells was quantified. By RT-PCR the βIII-TUB and GFAP differentiation genes were evaluated.

KEY FINDINGS

GS were maintained until passage four. The expression of all GSCs markers was significantly higher in GS as compared with the basal culture of U251 and U87 cells. We demonstrated for the first time that PR is expressed in GS and this expression was higher as compared with the U251 and U87 cells in basal conditions. Also, we observed that P increased the number of cells derived primary gliomaspheres (GS1) from the U251 line, as well as the expression of the neuronal differentiation marker βIII-TUB.

SIGNIFICANCE

These results suggest the participation of P in the growth of GSCs.

MiR-144 overexpression as a promising therapeutic strategy to overcome glioblastoma cell invasiveness and resistance to chemotherapy

Glioblastoma (GB) is the most aggressive and common form of primary brain tumor, characterized by fast proliferation, high invasion, and resistance to current standard treatment. The average survival rate post-diagnosis is only of 14.6 months, despite the aggressive standard post-surgery treatment approaches of radiotherapy concomitant with chemotherapy with temozolomide. Altered cell metabolism has been identified as an emerging cancer hallmark, including in GB, thus offering a new target for cancer therapies. On the other hand, abnormal expression levels of miRNAs, key regulators of multiple molecular pathways, have been correlated with pathological manifestations of cancer, such as chemoresistance, proliferation, and resistance to apoptosis. In this work, we hypothesized that gene therapy based on modulation of a miRNA with aberrant expression in GB and predicted to target crucial metabolic enzymes might impair tumor cell metabolism. We found that the increase of miR-144 levels, shown to be downregulated in U87 and DBTRG human GB cell lines, as well as in GB tumor samples, promoted the downregulation of mRNA of enzymes involved in bioenergetic pathways, with consequent alterations in cell metabolism, impairment of migratory capacity, and sensitization of DBTRG cells to a chemotherapeutic drug, the dichloroacetate (DCA). Taken together, our findings provide evidence that the miR-144 plus DCA combined therapy holds promise to overcome GB-acquired chemoresistance, therefore deserving to be explored toward its potential application as a complementary therapeutic approach to the current treatment options for this type of brain tumor.

Methods for in vitro modeling of glioma invasion: Choosing tools to meet the need

Widespread tumor cell invasion is a fundamental property of diffuse gliomas and is ultimately responsible for their poor prognosis. A greater understanding of basic mechanisms underlying glioma invasion is needed to provide insights into therapies that could potentially counteract them. While none of the currently available in vitro models can fully recapitulate the complex interactions of glioma cells within the brain tumor microenvironment, if chosen and developed appropriately, these models can provide controlled experimental settings to study molecular and cellular phenomena that are challenging or impossible to model in vivo. Therefore, selecting the most appropriate in vitro model, together with its inherent advantages and limitations, for specific hypotheses and experimental questions achieves primary significance. In this review, we describe and discuss commonly used methods for modeling and studying glioma invasion in vitro, including platforms, matrices, cell culture, and visualization techniques, so that choices for experimental approach are informed and optimal.

IGFBP5 increases cell invasion and inhibits cell proliferation by EMT and Akt signaling pathway in Glioblastoma multiforme cells

Background

Recurrence of Glioblastoma multiforme (GBM) seems to be the rule despite combination therapies. Cell invasion and cell proliferation are major reasons for recurrence of GBM. And insulin-like growth factor binding protein 5 (IGFBP5) is the most conserved of the IGFBPs and is frequently dysregulated in cancers and metastatic tissues.

Results

By studying the human glioma tissues, we find that IGFBP5 expression associate to the histopathological classification and highly expressed in GBM. Using IGFBP5 mutants we demonstrate that knockdown of IGFBP5 inhibited cell invasion, whereas promoting cell proliferation in GBM cells. Mechanistically, we observed that promoting GBM cell proliferation by inhibiting IGFBP5 was associated with stimulating Akt (Protein kinase B) phosphorylation. However, IGFBP5 promote GBM cell invasion was related to the epithelial-to-mesenchymal transition (EMT). Furthermore, the Chinese Glioma Genome Altas (CGGA) database show that IGFBP5 is significantly increased in recurrent glioma and it predicted worse survival.

Conclusions

The obtained results indicate that IGFBP5 has two sides in GBM—inhibiting cell proliferation but promoting cell invasion.

Combined-therapeutic strategies synergistically potentiate glioblastoma multiforme treatment via nanotechnology

Glioblastoma multiforme (GBM) is a highly aggressive and devastating brain tumor characterized by poor prognosis and high rates of recurrence. Numerous therapeutic strategies and delivery systems are developed to prolong the survival time. They exhibit enhanced therapeutic effects in animal models, whereas few of them is applied in clinical trials. Taking into account the drug-resistance and high recurrence of GBM, combined-therapeutic strategies are exploited to maximize therapeutic efficacy. The combined therapies demonstrate superior results than those of single therapies against GBM. The co-therapeutic agents, the timing of therapeutic strategies and the delivery systems greatly affect the overall outcomes. Herein, the current advances in combined therapies for glioblastoma via systemic administration are exhibited in this review. And we will discuss the pros and cons of these combined-therapeutic strategies via nanotechnology, and provide the guidance for developing rational delivery systems to optimize treatments against GBM and other malignancies in central nervous system.

The Personalisation of Glioblastoma Treatment Using Whole Exome Sequencing: A Pilot Study

The molecular heterogeneity of glioblastoma has been linked to differences in survival and treatment response, while the development of personalised treatments may be a novel way of combatting this disease. Here we show for the first time that low passage number cells derived from primary tumours are greater than an 86% match genetically to the tumour tissue. We used these cells to identify eight genes that could be used for the personalisation of glioblastoma treatment and discovered a number of personalised drug combinations that were significantly more effective at killing glioblastoma cells and reducing recurrence than the individual drugs as well as the control and non-personalised combinations. This pilot study demonstrates for the first time that whole exome sequencing has the potential be used to improve the treatment of glioblastoma patients by personalising treatment. This novel approach could potentially offer a new avenue for treatment for this terrible disease.

Germ Cell-Specific Gene 1-Like Protein Regulated by Splicing Factor CUGBP Elav-Like Family Member 5 and Primary Bile Acid Biosynthesis are Prognostic in Glioblastoma Multiforme

Background

Alternative splicing (AS) modifies 92-94% human genes, abnormal splicing events might relate to tumor development and invasion. Glioblastoma Multiforme (GBM) is a fatal, invasive, and malignant tumor in nervous system. The recurrence and development leads to poor prognosis. However, few studies have focused on AS in GBM.

Methods

RNA-seq and Alternative splicing events (ASEs) data of GBM samples were downloaded from The Cancer Genome Atlas (TCGA) and TCGASpliceSeq databases, respectively. Firstly, the Cox regression analysis was utilized to identify the overall survival splicing events (OS-SEs). Secondly, a multivariable model was applied to access the prognostic value of risk score. Then, we constructed a co-expressed network between splicing factors (SFs) and overall survival alternative splicing events (OS-SEs). Additionally, to explore the relationship between the potential prognostic signaling pathways and OS-SEs, we constructed a network between these pathways and OS-SEs. Ultimately, to better explain the results, validations from multi-dimension platforms were applied.

Results

In the first step, 1,062 OS-SEs were selected by Cox regression. Then, 11 OS-SEs were integrated in a multivariate model by Lasso regression. The area under the curve (AUC) of receiver operator characteristic (ROC) curve was 0.861. In addition, the risk score generated from the multivariate model was confirmed to be an independent prognostic factor (P < 0.001). What's more, in the network of SFs and ASEs, CELF5 significantly regulated GSG1L|35696|AP and GSG1L|35698|AP (P < 0.001, R = 0.511 and = -0.492). Additionally, GSG1L|35696|AP (P = 0.006) and GSG1L|35698|AP (P = 0.007) showed a significant relationship with cancer status. Eventually, KEGG pathways related to prognosis of GBM were selected by GSVA. The primary bile acid synthesis (P < 0.001, R = 0.420) was the significant pathway co-expressed with Germ Cell-Specific Gene 1-Like Protein (GSG1L).

Conclusions

Based on the comprehensive bioinformatics analysis, we proposed that aberrant splicing factor CUGBP Elav-like family member 5 (CELF5) significantly, positively and negatively, regulated ASE of GSG1L, and the primary bile acid synthesis pathway might play an important role in tumorigenesis and prognosis of GBM.

Improving the Oral Bioavailability of an Anti-Glioma Prodrug CAT3 Using Novel Solid Lipid Nanoparticles Containing Oleic Acid-CAT3 Conjugates

13a-(S)-3-pivaloyloxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (CAT3) is a novel oral anti-glioma pro-drug with a potent anti-tumor effect against temozolomide-resistant glioma in vivo. However, poor lipid solubility has limited the encapsulation efficacy during formulation development. Moreover, although the active metabolite of CAT3, 13a(S)-3-hydroxyl-6,7-dimethoxyphenanthro(9,10-b)-indolizidine (PF403), can penetrate the blood-brain barrier and approach the brain tissue with a 1000-fold higher anti-glioma activity than CAT3 in vitro, its bioavailability and Cmax were considerably low in plasma, limiting the anti-tumor efficacy. In this study, a novel oleic acid-CAT3 conjugate (OA-CAT3) was synthesized at the first time to increase the lipid solubility of CAT3. The OA-CAT3 loaded solid lipid nanoparticles (OA-CAT3-SLN) were constructed using an ultrasonic technique to enhance the bioavailability and Cmax of PF403 in plasma. Our results demonstrated that CAT3 was amorphous in the lipid core of OA-CAT3-SLN and the in vitro release was well controlled. Furthermore, the encapsulation efficacy and the zeta potential increased to 80.65 ± 6.79% and -26.7 ± 0.46 mV, respectively, compared to the normal CAT3 loaded SLN. As indicated by the high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) quantitation, the monolayer cellular transepithelial transport rate of OA-CAT3-SLN improved by 2.42-fold relied on cholesterol compared to the CAT3 suspension. Hence, the in vitro cell viability of OA-CAT3-SLN in C6 glioma cells decreased to 29.77% ± 2.13% and 10.75% ± 3.12% at 48 and 72 h, respectively. Finally, compared to the CAT3 suspension, the in vivo pharmacokinetics in rats indicated that the plasma bioavailability and Cmax of PF403 as afforded by OA-CAT3-SLN increased by 1.7- and 5.5-fold, respectively. Overall, the results indicate that OA-CAT3-SLN could be an efficacious delivery system in the treatment of glioma.

PABPC1-induced stabilization of BDNF-AS inhibits malignant progression of glioblastoma cells through STAU1-mediated decay

Glioblastoma is the most common and malignant form of primary central nervous tumor in adults. Long noncoding RNAs (lncRNAs) have been reported to play a pivotal role in modulating gene expression and regulating human tumor’s malignant behaviors. In this study, we confirmed that lncRNA brain-derived neurotrophic factor antisense (BDNF-AS) was downregulated in glioblastoma tissues and cells, interacted and stabilized by polyadenylate-binding protein cytoplasmic 1 (PABPC1). Overexpression of BDNF-AS inhibited the proliferation, migration, and invasion, as well as induced the apoptosis of glioblastoma cells. In the in vivo study, PABPC1 overexpression combined with BDNF-AS overexpression produced the smallest tumor and the longest survival. Moreover, BDNF-AS could elicit retina and anterior neural fold homeobox 2 (RAX2) mRNA decay through STAU1-mediated decay (SMD), and thereby regulated the malignant behaviors glioblastoma cells. Knockdown of RAX2 produced tumor-suppressive function in glioblastoma cells and increased the expression of discs large homolog 5 (DLG5), leading to the activation of the Hippo pathway. In general, this study elucidated that the PABPC1-BDNF-AS-RAX2-DLG5 mechanism may contribute to the anticancer potential of glioma cells and may provide potential therapeutic targets for human glioma.

Expression and function of chondroitin 4-sulfate and chondroitin 6-sulfate in human glioma

Key molecules promoting migration and invasion exist in the extracellular matrix, and include chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate (C6S), functionally important carbohydrate chains of chondroitin sulfate proteoglycans that participate in regulating cancer development. Here, we show that C4S and C6S expression is upregulated in human glioma tissues, when compared to normal brain tissue, and that the extent of upregulation positively correlated with glioma malignancy. Treatment of cultured glioma cells with C4S and C6S enhanced cell viability, migration, and invasion, increased MMP-2 and MMP-9 levels, enhanced N-cadherin, but reduced E-cadherin expression. Inhibition of expression of the two CS synthetic enzymes chondroitin 4-O-sulfotransferase-1 (C4ST-1/CHST11) and chondroitin 6-O-sulfotransferase-1 (C6ST-1/CHST3) suppressed cell viability, migration and invasion, reduced MMP-2 and MMP-9 expression, and reduced N-cadherin expression, but increased E-cadherin levels. The C4S- and C6S-enhanced epithelial-to-mesenchymal transition and expression of MMP-2 occurred via activation of the PI3K/AKT signaling pathway, known to be involved in promoting cell migration and invasion. In immune-deficient larval zebrafish, C4S and C6S increased the numbers of viable tumor cells, thereby promoting glioma cell proliferation. The present observations point to a novel role of C4S and C6S in human glioma cell functions, thus possibly representing targets in glioma therapy.

Differentiation of supratentorial single brain metastasis and glioblastoma by using peri-enhancing oedema region-derived radiomic features and multiple classifiers

OBJECTIVE

To differentiate supratentorial single brain metastasis (MET) from glioblastoma (GBM) by using radiomic features derived from the peri-enhancing oedema region and multiple classifiers.

METHODS

One hundred and twenty single brain METs and GBMs were retrospectively reviewed and then randomly divided into a training data set (70%) and validation data set (30%). Quantitative radiomic features of each case were extracted from the peri-enhancing oedema region of conventional MR images. After feature selection, five classifiers were built. Additionally, the combined use of the classifiers was studied. Accuracy, sensitivity, and specificity were used to evaluate the classification performance.

RESULTS

A total of 321 features were extracted, and 3 features were selected for each case. The 5 classifiers showed an accuracy of 0.70 to 0.76, sensitivity of 0.57 to 0.98, and specificity of 0.43 to 0.93 for the training data set, with an accuracy of 0.56 to 0.64, sensitivity of 0.39 to 0.78, and specificity of 0.50 to 0.89 for the validation data set. When combining the classifiers, the classification performance differed according to the combined mode and the agreement pattern of classifiers, and the greatest benefit was obtained when all the classifiers reached agreement using the same weight and simple majority vote method.

CONCLUSIONS

Three features derived from the peri-enhancing oedema region had moderate value in differentiating supratentorial single brain MET from GBM with five single classifiers. Combined use of classifiers, like multi-disciplinary team (MDT) consultation, could confer extra benefits, especially for those cases when all classifiers reach agreement.

KEY POINTS

• Radiomics provides a way to differentiate single brain MET between GBM by using conventional MR images. • The results of classifiers or algorithms themselves are also data, the transformation of the primary data. • Like MDT consultation, the combined use of multiple classifiers may confer extra benefits.

Design of new protein drug delivery system (PDDS) with photoactive compounds as a potential application in the treatment of glioblastoma brain cancer

Glioblastoma multiforme (GBM) is an extremely aggressive malignant brain tumor. Despite advances in treatment modalities, it remains largely incurable. This unfavorable prognosis for GBM is at least partly due to the lack of a successful drug delivery system across the blood-brain barrier (BBB). The delivery of drugs through nanomedicines combined with less invasive alternative therapies represents an important hope for the future of these incurable brain tumors. Whey protein nanocarriers represent promising strategy for targeted drug delivery to tumor cells by enhancing the drug's bioavailability and distribution, and reducing the body's response towards drug resistance. They have been extensively studied to find new alternatives for capacity to encapsulate different drugs and no need for cross-linkers. In this study, we report for the first time the incorporation and administration of Aluminum phthalocyanine chloride (AlClPc)-loaded whey protein drug delivery system (AlClPc-PDDS) for the treatment of glioblastoma brain cancer. This system was designed and optimized (with the use of the spray drying technique) to obtain the required particle size (in the range of 100 to 300 nm), zeta potential and drug loading. Our results suggest that we have developed a drug delivery system from a low-cost raw material and preparation method that is capable of incorporating hydrophobic drugs which, in combination with irradiation, cause photodamage to neoplasic cells, working as an effective adjuvant treatment for malignant glioma.

Magnetic iron oxide nanoparticles for imaging, targeting and treatment of primary and metastatic tumors of the brain

Magnetic nanoparticles in general, and iron oxide nanoparticles in particular, have been studied extensively during the past 20 years for numerous biomedical applications. The main applications of these nanoparticles are in magnetic resonance imaging (MRI), magnetic targeting, gene and drug delivery, magnetic hyperthermia for tumor treatment, and manipulation of the immune system by macrophage polarization for cancer treatment. Recently, considerable attention has been paid to magnetic particle imaging (MPI) because of its better sensitivity compared to MRI. In recent years, MRI and MPI have been combined as a dual or multimodal imaging method to enhance the signal in the brain for the early detection and treatment of brain pathologies. Because magnetic and iron oxide nanoparticles are so diverse and can be used in multiple applications such as imaging or therapy, they have attractive features for brain delivery. However, the greatest limitations for the use of MRI/MPI for imaging and treatment are in brain delivery, with one of these limitations being the brain-blood barrier (BBB). This review addresses the current status, chemical compositions, advantages and disadvantages, toxicity and most importantly the future directions for the delivery of iron oxide based substances across the blood-brain barrier for targeting, imaging and therapy of primary and metastatic tumors of the brain.

Iron and copper complexes with antioxidant activity as inhibitors of the metastatic potential of glioma cells

Iron and copper complexes with antioxidant activity able to inhibit tumor metastasis by inhibiting epithelial-mesenchymal transition in glioma cells.

A natural compound obtained from Valeriana jatamansi selectively inhibits glioma stem cells

Glioblastoma is one of the most malignant tumors with very poor prognosis. Glioma stem cells (GSCs) occupy a small proportion in glioma, but they are closely associated with radiotherapy and chemotherapy resistance, promoting tumor angiogenesis, hypoxia response, invasion and recurrence. Therefore, GSCs have become a new target for tumor treatment and are used in drug screening. Rupesin E is a natural compound obtained from Valeriana jatamansi, and its antitumor activity has not been reported. In the present study, the antitumor activity of rupesin E was investigated, and the results demonstrated that it inhibited the proliferation of GSCs (GSC-3#, GSC-12#, GSC-18#) with the IC₅₀ values of 7.13±1.41, 13.51±1.46 and 4.44±0.22 µg/ml, respectively. In addition, immunofluorescence cell staining and flow cytometry techniques demonstrated that rupesin E inhibited GSC proliferation and induced apoptosis. Furthermore, rupesin E inhibited the ability of GSC colony formation, indicating its antitumor activity against GSCs in vitro.

A tropomyosin-like Meretrix meretrix Linnaeus polypeptide inhibits the proliferation and metastasis of glioma cells via microtubule polymerization and FAK/Akt/MMPs signaling

Glioblastoma (GBM) represents the most common, aggressive and deadliest primary tumors with poor prognosis as available therapeutic approaches fail to control its aberrant proliferation and high invasiveness. Thus, the therapeutic agents targeting these two characteristics will be more effective. In present study, a novel polypeptide (MM15), which was originally purified from Meretrix meretrix Linnaeus and has been proven to possess potent antitumor activity by our laboratory, was recombinant expressed and identified as a tropomyosin homologous protein. The recombinant polypeptide (re-MM15) could induce the U87 cell cycle arrest in G2/M phase and cell apoptosis by inducing tubulin polymerization. Additionally, re-MM15 displayed the significant inhibition to the migration and invasion of U87 cells through downregulating FAK/Akt/MMPs signaling. Furthermore, the in vivo analysis suggested that re-MM15 significantly blocked tumor growth in U87 xenograft model. Collectively, our results indicated that re-MM15, with anti-GBM properties in vitro and in vivo, has promising potential as a new anticancer candidate for GBM.

Cerebellar glioblastoma multiforme in an adult patient with neurofibromatosis type 1: an extremely rare report with review of literature

Background

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder with autosomal dominant inheritance which predisposes the affected individuals to increased risk of developing certain benign and malignant central nervous system (CNS) tumors. NF1 patients are most notably prone to develop low-grade optic pathway, brainstem, and cerebellar astrocytoma. Current literature suggests that brain tumors in patients with NF1 tend to be less aggressive compared to sporadic ones. Glioblastoma multiforme (GBM) is a high-grade glioma which is relatively rare in patients with NF1 and is most commonly seen in supratentorial regions of the brain.

Case presentation

A 33-year-old patient was admitted in neurosurgery ward with acute hydrocephalus caused by a cerebellar mass lesion. On primary assessment, the patient was diagnosed with NF1. He was followed for 2 months and underwent surgical resection of the mass due to worsening symptoms. The pathology report revealed the malignant nature of the lesion. Patient received adjuvant chemo-radiotherapy with diagnosis of cerebellar GBM. Up to 19 months following surgery, he had gained a relatively well ability to walk and talk again.

Dual and multi-targeted nanoparticles for site-specific brain drug delivery

In recent years, nanomedicines have emerged as a promising method for central nervous system drug delivery, enabling the drugs to overcome the blood-brain barrier and accumulate preferentially in the brain. Despite the current success of brain-targeted nanomedicines, limitations still exist in terms of the targeting specificity. Based on the molecular mechanism, the exact cell populations and subcellular organelles where the injury occurs and the drugs take effect have been increasingly accepted as a more specific target for the next generation of nanomedicines. Dual and multi-targeted nanoparticles integrate different targeting functionalities and have provided a paradigm for precisely delivering the drug to the pathological site inside the brain. The targeting process often involves the sequential or synchronized navigation of the targeting moieties, which allows highly controlled drug delivery compared to conventional targeting strategies. Herein, we focus on the up-to-date design of pathological site-specific nanoparticles for brain drug delivery, highlighting the dual and multi-targeting strategies that were employed and their impact on improving targeting specificity and therapeutic effects. Furthermore, the background discussion of the basic properties of a brain-targeted nanoparticle and the common lesion features classified by neurological pathology are systematically summarized.

Lateral or Medial Surgical Approaches for Thalamic Gliomas Resection?

OBJECTIVE

This study aimed to investigate the selection, safety, and prognosis of medial (transcorpus callosal) and lateral (translateral brain gyrus) approaches for adult thalamic glioma resection.

METHODS

The medical records of adult patients with thalamic glioma between March 2006 and March 2016 in Huashan Hospital were reviewed. The probabilistic map of the gliomas was shown in Montreal Neurological Institute (MNI) space, and a paralleling midline was delineated to decide the approach. The extent of resection, complications, adjuvant treatment, and survival data were analyzed. A literature review was also conducted.

RESULTS

Fifty-three patients with thalamic glioma were enrolled. Eighteen patients received tumor resection by a medial approach and 35 by a lateral approach. The probabilistic map based on 20 patients showed that 9 gliomas with ≥45% located in the medial side were treated medially and the other 11 gliomas were treated laterally. Both approaches achieved adequate extent of resection with similar morbidity. Kaplan-Meier analysis showed no significant difference of overall survival by a transcorpus callosal or translateral brain gyrus approach. Total resection (TR) or subtotal resection (STR) (P = 0.0003), radiochemotherapy (P < 0.0001), and low-grade glioma (P = 0.031) were correlated with better OS. Multivariate Cox regression analysis showed that TR/STR (P = 0.007; 95% confidence interval, 1.345-6.287) and radiochemotherapy (P < 0.0001; 95% confidence interval, 4.740-71.569) were independent prognostic factors for adult thalamic gliomas.

CONCLUSIONS

Both medial and lateral approaches are feasible and adequate for resection of thalamic gliomas. The paramidline paralleling midline crossing the genu of the internal capsule could help make the choice. TR/STR, radiochemotherapy, and low-grade glioma could benefit the prognosis.

ACSL4 suppresses glioma cells proliferation via activating ferroptosis

Acyl-CoA synthetase long-chain family member 4 (ACSL4) is a member of the long chain family of acyl-CoA synthetase proteins, which have recently been shown to serve an important role in ferroptosis. Previous studies have suggested that ferroptosis is involved in the occurrence of glioma; however, the role of ACSL4 in glioma remains unknown. In the present study, a reduction of ferroptosis in human glioma tissues and glioma cells was observed. Subsequently, it was demonstrated that the expression of ACSL4 was also downregulated in human glioma tissues and cells. A ferroptosis inhibitor and inducer were used to investigate the effects of ferroptosis on viability. The results showed that promoting ferroptosis inhibited the proliferation of glioma cells, and that the use of inducers had the reverse effect. Therefore, it was hypothesized that the reduction in ACSL4 expression may have been involved in ferroptosis and proliferation in glioma. Overexpression of ACSL4 decreased expression of glutathione peroxidase 4 and increased the levels of ferroptotic markers, including 5-hydroxyeicosatetraenoic (HETE), 12-HETE and 15-HETE. Additionally, ACSL4 overexpression resulted in an increase in lactate dehydrogenase release and a reduction in cell viability. The opposite results were observed when ACSL4 was silenced. These findings suggest that ACSL4 regulates ferroptosis and proliferation of glioma cells. To further investigate the mechanism underlying ACSL4-mediated regulation of proliferation in glioma cells, cells were treated with small interfering (si)-ACSL4 and sorafenib, a ferroptosis inducer. sorafenib attenuated the ability of siRNA-mediated silencing of ACSL4, thus improving cell viability. These results demonstrate that ACSL4 protects glioma cells and exerts anti-proliferative effects by activating a ferroptosis pathway and highlight the pivotal role of ferroptosis regulation by ACSL4 in its protective effects on glioma. Therefore, ACSL4 may serve as a novel therapeutic target for the treatment of glioma.

A Pediatric Case of Glioblastoma Multiforme Associated With a Novel Germline p.His112CysfsTer9 Mutation in the MLH1 Gene Accompanied by a p.Arg283Cys Mutation in the TP53 Gene: A Case Report

Targeted gene panel testing has the power to interrogate hundreds of genes and evaluate the genetic risk for many types of hereditary cancers simultaneously. We screened a 13-year-old male patient diagnosed with glioblastoma multiforme with the aim to get further insights into the biology of his condition. Herein, we applied gene panel sequencing and identified a heterozygous frameshift mutation c.333_334delTC; p.His112CysfsTer9 in the MLH1 gene in blood and tumor tissue accompanied by a known heterozygous missense variant of unknown significance c.847C > T; p.Arg283Cys in the TP53 gene. Parental screening revealed the presence of the same TP53 variant in the father and the same MLH1 variant in the mother, who was in fact undergoing treatment for early-stage breast cancer at the time of her son's unfortunate diagnosis. This case reports for the first time the co-occurrence of a genetic mutation in the MLH1 gene of the mismatch repair pathway, commonly associated with the Lynch syndrome, accompanied by a rare variant in the TP53 gene. This report underlines the need for broad panel gene testing in lieu of single-gene or syndrome-focused gene screening and evaluation of the effects of multiple pathogenic or modifier variants on the phenotypic spectrum of the disease.

Zika Virus as Oncolytic Therapy for Brain Cancer: Myth or Reality?

The ability of self-replicating oncolytic viruses (OVs) to preferentially infect and lyse cancer cells while stimulating anti-tumor immunity of the host strongly indicates its value as a new field of cancer therapeutics to be further explored. The emergence of Zika virus (ZIKV) as a global health threat due to its recent outbreak in Brazil has caught the attention of the scientific community and led to the discovery of its oncolytic potential for the treatment of glioblastoma multiforme (GBM), the most common and fatal brain tumor with poor prognosis. Herein, we evaluate the neurotropism of ZIKV relative to the receptor tyrosine kinase AXL and its ligand Gas6 in viral entry and the RNA-binding protein Musashi-1 (MSI1) in replication which are also overexpressed in GBM, suggesting its potential for specific targeting of the tumor. Additionally, this review discusses genetic modifications performed to enhance safety and efficacy of ZIKV as well as speculates future directions for the OV therapy.

Low expression or hypermethylation of PLK2 might predict favorable prognosis for patients with glioblastoma multiforme

Background

As the most aggressive brain tumor, patients with glioblastoma multiforme (GBM) have a poor prognosis. Our purpose was to explore prognostic value of Polo-like kinase 2 (PLK2) in GBM, a member of the PLKs family.

Methods

The expression profile of PLK2 in GBM was obtained from The Cancer Genome Atlas database. The PLK2 expression in GBM was tested. Kaplan–Meier curves were generated to assess the association between PLK2 expression and overall survival (OS) in patients with GBM. Furthermore, to assess its prognostic significance in patients with primary GBM, we constructed univariate and multivariate Cox regression models. The association between PLK2 expression and its methylation was then performed. Differentially expressed genes correlated with PLK2 were identified by Pearson test and functional enrichment analysis was performed.

Results

Overall survival results showed that low PLK2 expression had a favorable prognosis of patients with GBM (P-value = 0.0022). Furthermore, PLK2 (HR = 0.449, 95% CI [0.243–0.830], P-value = 0.011) was positively associated with OS by multivariate Cox regression analysis. In cluster 5, DNA methylated PLK2 had the lowest expression, which implied that PLK2 expression might be affected by its DNA methylation status in GBM. PLK2 in CpG island methylation phenotype (G-CIMP) had lower expression than non G-CIMP group (P = 0.0077). Regression analysis showed that PLK2 expression was negatively correlated with its DNA methylation (P = 0.0062, Pearson r = −0.3855). Among all differentially expressed genes of GBM, CYGB (r = 0.5551; P < 0.0001), ISLR2 (r = 0.5126; P < 0.0001), RPP25 (r = 0.5333; P < 0.0001) and SOX2 (r = −0.4838; P < 0.0001) were strongly correlated with PLK2. Functional enrichment analysis results showed that these genes were enriched several biological processes or pathways that were associated with GBM.

Conclusion

Polo-like kinase 2 expression is regulated by DNA methylation in GBM, and its low expression or hypermethylation could be considered to predict a favorable prognosis for patients with GBM.

Glioma and Neurokinin-1 Receptor Antagonists: A New Therapeutic Approach

BACKGROUND

In adults, the most lethal and frequent primary brain tumor is glioblastoma. Despite multimodal aggressive therapies, the median survival time after diagnosis is around 15 months. In part, this is due to the blood-brain barrier that restricts common treatments (e.g., chemotherapy). Unfortunately, glioma recurs in 90% of patients. New therapeutic strategies against glioma are urgently required. Substance P (SP), through the neurokinin (NK)-1 receptor, controls cancer cell proliferation by activating c-myc, mitogenactivated protein kinases, activator protein 1 and extracellular signal-regulated kinases 1 and 2. Glioma cells overexpress NK-1 receptors when compared with normal cells. The NK-1 receptor/SP system regulates the proliferation/migration of glioma cells and stimulates angiogenesis, triggering inflammation which contributes to glioma progression. In glioma cells, SP favors glycogen breakdown, essential for glycolysis. By contrast, in glioma, NK-1 receptor antagonists block the proliferation of tumor cells and the breakdown of glycogen and also promote the death (apoptosis) of these cells. These antagonists also inhibit angiogenesis and exert antimetastatic and anti-inflammatory actions.

OBJECTIVE

This review updates the involvement of the NK-1 receptor/SP system in the development of glioma and the potential clinical application of NK-1 receptor antagonists as antiglioma agents.

CONCLUSION

The NK-1 receptor plays a crucial role in glioma and NK-1 receptor antagonists could be used as anti-glioma drugs.

miR‑489 promotes apoptosis and inhibits invasiveness of glioma cells by targeting PAK5/RAF1 signaling pathways

Glioma patients receiving therapy are at a high risk of relapse and rapid progression and, thus, more effective treatments are required. The aim of the present study was to determine the suppressive role of miR-489 as an alternative therapeutic target for preventing glioma progression. The results of the present study demonstrated that patients with relatively lower levels of expression of miR-489 had more favorable clinical outcomes. Furthermore, miR-489 expression was inversely correlated with p21-activated kinase 5 (PAK5) mRNA expression levels in glioma specimens. A dual luciferase reporter assay revealed that miR-489 suppressed PAK5 expression by directly targeting the PAK5 3′-untranslated region. The effects of miR-489 on cell viability were measured using MTT and Cell Counting Kit-8 assays. The results demonstrated that ectopic expression of miR-489 mimic decreased cell viability by interfering with cyclin D1 and c-Myc signaling. Additionally, the effect of miR-489 on apoptosis was determined using Hoechst 33258 staining and flow cytometry. The results demonstrated that miR-489 decreased the activity of RAF1, reduced Bcl-2 and promoted Bax expression, resulting in increased cell apoptosis. Furthermore, the effect of miR-489 mimic on cellular motility was assessed using migration and invasion assays. miR-489 was shown to abolish the PAK5/RAF1/MMP2 pathway, resulting in decreased cell invasion ability. These results indicated that miR-489 may be involved in PAK5-mediated regulation of glioma progression, demonstrating the potential therapeutic benefits of targeting miR-489 in glioma.

Monoamines in glioblastoma: complex biology with therapeutic potential

Glioblastoma (GBM) is characterized by extremely poor prognoses, despite the use of gross surgical resection, alkylating chemotherapeutic agents, and radiotherapy. Evidence increasingly highlights the role of the tumor microenvironment in enabling this aggressive phenotype. Despite this interest, the role of neurotransmitters, brain-specific messengers underlying synaptic transmission, remains murky. These signaling molecules influence a complex network of molecular pathways and cellular behaviors in many CNS-resident cells, including neural stem cells and progenitor cells, neurons, and glia cells. Critically, available data convincingly demonstrate that neurotransmitters can influence proliferation, quiescence, and differentiation status of these cells. This ability to affect progenitors and glia-GBM-initiating cells-and their availability in the CNS strongly support the notion that neurotransmitters participate in the onset and progression of GBM. This review will focus on dopamine and serotonin, as studies indicate they contribute to gliomagenesis. Particular attention will be paid to how these neurotransmitters and their receptors can be utilized as novel therapeutic targets. Overall, this review will analyze the complex biology governing the interaction of GBM with neurotransmitter signaling and highlight how this interplay shapes the aggressive nature of GBM.

Neurokinin-1 Receptor Antagonists as Anticancer Drugs

Background::

Human tumor cells lines and tumor samples overexpress the neurokinin-1 receptor (NK-1R). Substance P (SP), after binding to NK-1Rs, induces tumor cell proliferation, an antiapoptotic effect and promotes angiogenesis and the migration of cancer cells for invasion and metastasis.

Methods: :

In contrast, NK-1R antagonists block the previous pathophysiological actions mediated by SP. These antagonists promote the death of tumor cells by apoptosis. Peptide and non-peptide NK-1R antagonists have been reported.

Results: :

Peptide NK-1R antagonists show chemical modifications of the SP molecule (L-amino acids being replaced by D-amino acids), whereas non-peptide NK-1R antagonists include numerous compounds with different chemical compositions while showing similar stereochemical features (affinity for the NK- 1R). Currently, there are more than 300 NK-1R antagonists.

Conclusion::

In combination therapy with classic cytostatics, NK-1R antagonists have additive or synergic effects and minimize the side-effects of cytostatics. The effect of NK-1R antagonists as broad-spectrum anticancer drugs is reviewed and the use of these antagonists for the treatment of cancer is suggested.

Systematic Evaluation of Transferrin-Modified Porous Silicon Nanoparticles for Targeted Delivery of Doxorubicin to Glioblastoma

There is a dire need to develop more effective therapeutics to combat brain cancer such as glioblastoma multiforme (GBM). An ideal treatment is expected to target deliver chemotherapeutics to glioma cells across the blood-brain barrier (BBB). The overexpression of transferrin (Tf) receptor (TfR) on the BBB and the GBM cell surfaces but not on the surrounding cells renders TfR a promising target. While porous silicon nanoparticles (pSiNPs) have been intensely studied as a delivery vehicle due to their high biocompatibility, degradability, and drug-loading capacity, the potential to target deliver drugs with transferrin (Tf)-functionalized pSiNPs remains unaddressed. Here, we developed and systematically evaluated Tf-functionalized pSiNPs (Tf@pSiNPs) as a glioma-targeted drug delivery system. These nanoparticles showed excellent colloidal stability and had a low toxicity profile. As compared with nontargeted pSiNPs, Tf@pSiNPs were selective to BBB-forming cells and GBM cells and were efficiently internalized through clathrin receptor-mediated endocytosis. The anticancer drug doxorubicin (Dox) was effectively loaded (8.8 wt %) and released from Tf@pSiNPs in a pH-responsive manner over 24 h. Furthermore, the results demonstrate that Dox delivered by Tf@pSiNPs induced significantly enhanced cytotoxicity to GBM cells across an in vitro BBB monolayer compared with free Dox. Overall, Tf@pSiNPs offer a potential toolbox for enabling targeted therapy to treat GBM.

Modulation of glioma-inflammation crosstalk profiles in human glioblastoma cells by indirubin-3'-(2,3 dihydroxypropyl)-oximether (E804) and 7-bromoindirubin-3'-oxime (7BIO)

Indirubins E804 (indirubin-3'-(2,3 dihydroxypropyl)-oximether) and 7BIO (7-Bromoindirubin-3'-oxime) are synthetic derivatives of natural indirubin, the active compound in Danggui Longhui Wan, a traditional Chinese remedy for cancer and inflammation. Herein, we explore E804 and 7BIO for their potential to modulate key pro-inflammatory genes and cytokines in LN-18 and T98G glioblastoma cells. High grade gliomas typically secrete large amounts of inflammatory cytokines and growth factors that promote tumor growth in an autocrine fashion. Inflammation is emerging as a key concern in the success of new treatment modalities for glioblastomas. Studies indicate that select indirubin derivatives bind and activate signaling of the AHR pathway, as well as inhibit cyclin-dependent kinases and STAT3 signaling. AHR signaling is involved in hematopoiesis, immune function, cell cycling, and inflammation, and thus may be a possible target for glioma treatment. To determine the significance of the AHR pathway in LN-18 and T98G glioma inflammatory profiles, and on the effects of E804 and 7BIO on these profiles, we used 6,2',4'-trimethoxyflavone (TMF), a putative selective AHR antagonist. It was confirmed that E804 and 7BIO activates the AHR leading to cyp1b1 expression, and that TMF antagonizes expression. We then employed a commercial cancer inflammation and immunity crosstalk qRT-PCR array to screen for anti-inflammatory related properties. TMF alone inhibited expression of ifng, ptsg2, il12b, tnfa, il10, il13, the balance between pd1 and pdl1, and even expression of mhc1a/b. E804 was very potent in suppressing many pro-inflammatory genes, including il1a, il1b, il12a, ptgs2, tlr4, and others. E804 also affected expression of il6, vegfa, and stat3. Conversely, 7BIO induced cox2, but suppressed a different selection of pro-inflammatory genes including nos2, tnfa, and igf1. Secretion of IL-6 protein, an iconic inflammatory cytokine, was decreased by E804. VEGF (vascular endothelial growth factor) protein secretion was upregulated by 7BIO, yet downregulated by E804 and E804 plus TMF. Thus, E804 is both an AHR ligand and regulator of important pro-inflammatory cytokines such as IL-6 and oncogene STAT3, among others. Our results point to the use of E804 and TMF in combination as a promising new treatment for glioblastoma.

Evaluation of Elastin-Like Polypeptides for Tumor Targeted Delivery of Doxorubicin to Glioblastoma

To increase treatment efficiency for glioblastoma, we have developed a system to selectively deliver chemotherapeutic doxorubicin (Dox) to Glioblastoma (GBM) tumors. This carrier is based on elastin-like polypeptide (ELP), which is soluble at physiological temperatures but undergoes a phase transition and accumulates at tumor sites with externally applied, mild (40–41 °C) hyperthermia. The CPP-ELP-Dox conjugate consists of a cell penetrating peptide (CPP), which facilitates transcytosis through the blood brain barrier and cell entry, and a 6-maleimidocaproyl hydrazone derivative of doxorubicin at the C-terminus of ELP. The acid-sensitive hydrazone linker ensures release of Dox in the lysosomes/endosomes after cellular uptake of the drug conjugate. We have shown that CPP-ELP-Dox effectively inhibits cell proliferation in three GBM cell lines. Both the free drug and CPP-ELP-Dox conjugate exhibited similar in vitro cytotoxicity, although their subcellular localization was considerably different. The Dox conjugate was mainly dispersed in the cytoplasm, while free drug had partial nuclear accumulation in addition to cytoplasmic distribution. The intracellular Dox concentration was increased in the CPP-ELP-Dox cells compared to that in the cells treated with free Dox, which positively correlates with cytotoxic activity. In summary, our findings demonstrate that CPP-ELP-Dox effectively kills GBM cells. Development of such a drug carrier has the potential to greatly improve current therapeutic approaches for GBM by increasing the specificity and efficacy of treatment and reducing cytotoxicity in normal tissues.

ROS-Responsive Polymeric siRNA Nanomedicine Stabilized by Triple Interactions for the Robust Glioblastoma Combinational RNAi Therapy

Small interfering RNA (siRNA) holds inherent advantages and great potential for treating refractory diseases. However, lack of suitable siRNA delivery systems that demonstrate excellent circulation stability and effective at-site delivery ability is currently impeding siRNA therapeutic performance. Here, a polymeric siRNA nanomedicine (3I-NM@siRNA) stabilized by triple interactions (electrostatic, hydrogen bond, and hydrophobic) is constructed. Incorporating extra hydrogen and hydrophobic interactions significantly improves the physiological stability compared to an siRNA nanomedicine analog that solely relies on the electrostatic interaction for stability. The developed 3I-NM@siRNA nanomedicine demonstrates effective at-site siRNA release resulting from tumoral reactive oxygen species (ROS)-triggered sequential destabilization. Furthermore, the utility of 3I-NM@siRNA for treating glioblastoma (GBM) by functionalizing 3I-NM@siRNA nanomedicine with angiopep-2 peptide is enhanced. The targeted Ang-3I-NM@siRNA exhibits superb blood-brain barrier penetration and potent tumor accumulation. Moreover, by cotargeting polo-like kinase 1 and vascular endothelial growth factor receptor-2, Ang-3I-NM@siRNA shows effective suppression of tumor growth and significantly improved survival time of nude mice bearing orthotopic GBM brain tumors. New siRNA nanomedicines featuring triple-interaction stabilization together with inbuilt self-destruct delivery ability provide a robust and potent platform for targeted GBM siRNA therapy, which may have utility for RNA interference therapy of other tumors or brain diseases.

Nanoformulations for glioblastoma multiforme: a new hope for treatment

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, associated with a high mortality rate and a survival of between 12 and 15 months after diagnosis. Due to current treatment limitations involving surgery, radiotherapy and chemotherapy with temozolamide, there is a high rate of treatment failure and recurrence. To try to overcome these limitations nanotechnology has emerged as a novel alternative. Lipid, polymeric, silica and magnetic nanoparticles, among others, are being developed to improve GBM treatment and diagnosis. These nanoformulations have many advantages, including lower toxicity, biocompatibility and the ability to be directed toward the tumor. This article reviews the progress that have been made and the large variety of nanoparticles currently under study for GBM.

An Open-Source Tool for Anisotropic Radiation Therapy Planning in Neuro-oncology Using DW-MRI Tractography

There is evidence from histopathological studies that glioma tumor cells migrate preferentially along large white matter bundles. If the peritumoral white matter structures can be used to predict the likely trajectory of migrating tumor cells outside of the surgical margin, then this information could be used to inform the delineation of radiation therapy (RT) targets. In theory, an anisotropic expansion that takes large white matter bundle anatomy into account may maximize the chances of treating migrating cancer cells and minimize the amount of brain tissue exposed to high doses of ionizing radiation. Diffusion-weighted MRI (DW-MRI) can be used in combination with fiber tracking algorithms to model the trajectory of large white matter pathways using the direction and magnitude of water movement in tissue. The method presented here is a tool for translating a DW-MRI fiber tracking (tractography) dataset into a white matter path length (WMPL) map that assigns each voxel the shortest distance along a streamline back to a specified region of interest (ROI). We present an open-source WMPL tool, implemented in the package Diffusion Imaging in Python (DIPY), and code to convert the resulting WMPL map to anisotropic contours for RT in a commercial treatment planning system. This proof-of-concept lays the groundwork for future studies to evaluate the clinical value of incorporating tractography modeling into treatment planning.

Effects of Radiation Therapy on Neural Stem Cells

Brain and nervous system cancers in children represent the second most common neoplasia after leukemia. Radiotherapy plays a significant role in cancer treatment; however, the use of such therapy is not without devastating side effects. The impact of radiation-induced damage to the brain is multifactorial, but the damage to neural stem cell populations seems to play a key role. The brain contains pools of regenerative neural stem cells that reside in specialized neurogenic niches and can generate new neurons. In this review, we describe the advances in radiotherapy techniques that protect neural stem cell compartments, and subsequently limit and prevent the occurrence and development of side effects. We also summarize the current knowledge about neural stem cells and the molecular mechanisms underlying changes in neural stem cell niches after brain radiotherapy. Strategies used to minimize radiation-related damages, as well as new challenges in the treatment of brain tumors are also discussed.

Poly-ADP-ribose polymerases (PARPs) as a therapeutic target in the treatment of selected cancers

Introduction: The implementation of poly-ADP-ribose polymerase (PARP) inhibitors for therapy has created potential treatments for a wide spectrum of malignancies involving DNA damage repair gene abnormalities. PARPs are a group of enzymes that are responsible for detecting and repairing DNA damage and therefore play a key role in maintaining cell function and integrity. PARP inhibitors are drugs that target DNA repair deficiencies. Inhibiting PARP activity in cancer cells causes cell death. Areas covered: This review summarizes the role of PARP inhibitors in the treatment of cancer. We performed a systematic literature search in February 2019 in the electronic databases PubMed and EMBASE. Our search terms were the following: PARP, PARP inhibitors, PARPi, Poly ADP ribose polymerase, cancer treatment. We discuss PARP inhibitors currently being investigated in cancer clinical trials, their safety profiles, clinical resistance, combined therapeutic approaches and future challenges. Expert Opinion: The future could bring novel PARP inhibitors with greater DNA trapping potential, better safety profiles and improved combined therapies involving hormonal, chemo-, radio- or immunotherapies. Progress may afford wider indications for PARP inhibitors in the treatment of cancer and the utilization for cancer prevention in high-risk mutation carriers. Research efforts should focus on identifying novel drugs that target DNA repair deficiencies.

Mesenchymal stem cell therapy assisted by nanotechnology: a possible combinational treatment for brain tumor and central nerve regeneration

Mesenchymal stem cells (MSCs) intrinsically possess unique features that not only help in their migration towards the tumor-rich environment but they also secrete versatile types of secretomes to induce nerve regeneration and analgesic effects at inflammatory sites. As a matter of course, engineering MSCs to enhance their intrinsic abilities is growing in interest in the oncology and regenerative field. However, the concern of possible tumorigenesis of genetically modified MSCs prompted the development of non-viral transfected MSCs armed with nanotechnology for more effective cancer and regenerative treatment. Despite the fact that a large number of successful studies have expanded our current knowledge in tumor-specific targeting, targeting damaged brain site remains enigmatic due to the presence of a blood–brain barrier (BBB). A BBB is a barrier that separates blood from brain, but MSCs with intrinsic features of transmigration across the BBB can efficiently deliver desired drugs to target sites. Importantly, MSCs, when mediated by nanoparticles, can further enhance tumor tropism and can regenerate the damaged neurons in the central nervous system through the promotion of axon growth. This review highlights the homing and nerve regenerative abilities of MSCs in order to provide a better understanding of potential cell therapeutic applications of non-genetically engineered MSCs with the aid of nanotechnology.

Increased Nose-to-Brain Delivery of Melatonin Mediated by Polycaprolactone Nanoparticles for the Treatment of Glioblastoma

PURPOSE

Intranasal administration has been extensively applied to deliver drugs to the brain. In spite of its unfavorable biopharmaceutic properties, melatonin (MLT) has demonstrated anticancer effects against glioblastoma. This study describes the nose-to-brain delivery of MLT-loaded polycaprolactone nanoparticles (MLT-NP) for the treatment of glioblastoma.

METHODS

MLT-NP were prepared by nanoprecipitation. Following intranasal administration in rats, brain targeting of the formulation was demonstrated by fluorescence tomography. Brain and plasma pharmacokinetic profiles were analyzed. Cytotoxicity against U87MG glioblastoma cells and MRC-5 non-tumor cells was evaluated.

RESULTS

MLT-NP increased the drug apparent water solubility ~35 fold. The formulation demonstrated strong activity against U87MG cells, resulting in IC50 ~2500 fold lower than that of the free drug. No cytotoxic effect was observed against non-tumor cells. Fluorescence tomography images evidenced the direct translocation of nanoparticles from nasal cavity to the brain. Intranasal administration of MLT-NP resulted in higher AUC_brain and drug targeting index compared to the free drug by either intranasal or oral route.

CONCLUSIONS

Nanoencapsulation of MLT was crucial for the selective antitumoral activity against U87MG. In vivo evaluation confirmed nose-to-brain delivery of MLT mediated by nanoparticles, highlighting the formulation as a suitable approach to improve glioblastoma therapy.

Menthol-modified casein nanoparticles loading 10-hydroxycamptothecin for glioma targeting therapy

Chemotherapy outcomes for the treatment of glioma remains unsatisfactory due to the inefficient drug transport across the blood-brain barrier (BBB) and insufficient drug accumulation in the tumor region. Although many approaches, including various nanosystems, have been developed to promote the distribution of chemotherapeutics in the brain tumor, the delivery efficiency and the possible damage to the normal brain function still greatly restrict the clinical application of the nanocarriers. Therefore, it is urgent and necessary to discover more safe and effective BBB penetration and glioma-targeting strategies. In the present study, menthol, one of the strongest BBB penetration enhancers screened from traditional Chinese medicine, was conjugated to casein, a natural food protein with brain targeting capability. Then the conjugate self-assembled into the nanoparticles to load anti-cancer drugs. The nanoparticles were characterized to have appropriate size, spheroid shape and high loading drug capacity. Tumor spheroid penetration experiments demonstrated that penetration ability of menthol-modified casein nanoparticles (M-CA-NP) into the tumor were much deeper than that of unmodified nanoparticles. In vivo imaging further verified that M-CA-NPs exhibited higher brain tumor distribution than unmodified nanoparticles. The median survival time of glioma-bearing mice treated with HCPT-M-CA-NPs was significantly prolonged than those treated with free HCPT or HCPT-CA-NPs. HE staining of the organs indicated the safety of the nanoparticles. Therefore, the study combined the advantages of traditional Chinese medicine strategy with modern delivery technology for brain targeting, and provide a safe and effective approach for glioma therapy.