Dioscin decreases M2 polarization via inhibiting a positive feedback loop between RBM47 and NF-κB in glioma.

BACKGROUND: The role of the glioblastoma (GBM) microenvironment is pivotal in the development of gliomas. Discovering drugs that can traverse the blood-brain barrier and modulate the tumor microenvironment is crucial for the treatment of GBM. Dioscin, a steroidal saponin derived from various kinds of plants and herbs known to penetrate the blood-brain barrier, has shown its powerful anti-tumor activity. However, little is known about its effects on GBM microenvironment. METHODS: Bioinformatics analysis was conducted to assess the link between GBM patients and their prognosis. Multiple techniques, including RNA sequencing, immunofluorescence staining, Western blot analysis, RNA-immunoprecipitation (RIP) assays, and Chromatin immunoprecipitation (CHIP) analysis were employed to elucidate the mechanism through which Dioscin modulates the immune microenvironment. RESULTS: Dioscin significantly impaired the polarization of macrophages into the M2 phenotype and enhanced the phagocytic ability of macrophages in vitro and in vivo. A strong correlation between high expression of RBM47 in GBM and a detrimental prognosis for patients was demonstrated. RNA-sequencing analysis revealed an association between RBM47 and the immune response. The inhibition of RBM47 significantly impaired the recruitment and polarization of macrophages into the M2 phenotype and enhanced the phagocytic ability of macrophages. Moreover, RBM47 could stabilize the mRNA of inflammatory genes and enhance the expression of these genes by activating the NF-κB pathway. In addition, NF-κB acts as a transcription factor that enhances the transcriptional activity of RBM47. Notably, we found that Dioscin could significantly inhibit the activation of NF-κB and then downregulate the expression of RBM47 and inflammatory genes protein. CONCLUSION: Our study reveals that the positive feedback loop between RBM47 and NF-κB could promote immunosuppressive microenvironment in GBM. Dioscin effectively inhibits M2 polarization in GBM by disrupting the positive feedback loop between RBM47 and NF-κB, indicating its potential therapeutic effects in GBM treatment.

Comprehensive somatic mutational analysis in glioblastoma: Implications for precision medicine approaches.

Glioblastoma multiforme (GBM), a malignant neoplasm originating from glial cells, remains challenging to treat despite the current standard treatment approach that involves maximal safe surgical resection, radiotherapy, and adjuvant temozolomide chemotherapy. This underscores the critical need to identify new molecular targets for improved therapeutic interventions. The current study aimed to explore the somatic mutations and potential therapeutic targets in GBM using somatic mutational information from four distinct GBM datasets including CGGA, TCGA, CPTAC and MAYO-PDX. The analysis included the evaluation of whole exome sequencing (WES) of GBM datasets, tumor mutation burden assessment, survival analysis, drug sensitivity prediction, and examination of domain-specific amino acid changes. The results identified the top ten commonly altered genes in the aforementioned GBM datasets and patients with mutations in OBSCN and AHNAK2 alone or in combination had a more favorable overall survival (OS). Also, the study identified potential drug sensitivity patterns in GBM patients with mutations in OBSCN and AHNAK2, and evaluated the impact of amino acid changes in specific protein domains on the survival of GBM patients. These findings provide important insights into the genetic alterations and somatic interactions in GBM, which could have implications for the development of new therapeutic strategies for this aggressive malignancy.

Advances in Treatment of Diffuse Midline Gliomas.

PURPOSE OF REVIEW: Diffuse midline gliomas (DMGs) generally carry a poor prognosis, occur during childhood, and involve midline structures of the central nervous system, including the thalamus, pons, and spinal cord. RECENT FINDINGS: To date, irradiation has been shown to be the only beneficial treatment for DMG. Various genetic modifications have been shown to play a role in the pathogenesis of this disease. Current treatment strategies span targeting epigenetic dysregulation, cell cycle, specific genetic alterations, and the immune microenvironment. Herein, we review the complex features of this disease as it relates to current and past therapeutic approaches.

Supplementation with a high-glucose drink stimulates anti-tumor immune responses to glioblastoma via gut microbiota modulation.

A high-sugar diet induces lifestyle-associated metabolic diseases, such as obesity and diabetes, which may underlie the pro-tumor effects of a high-sugar diet. We supply GL261 syngeneic glioblastoma (GBM) mice with a short-term high-glucose drink (HGD) and find an increased survival rate with no evidence of metabolic disease. Modulation of the gut microbiota through HGD supplementation is critical for enhancing the anti-tumor immune response. Single-cell RNA sequencing shows that gut microbiota modulation by HGD supplementation increases the T cell-mediated anti-tumor immune response in GBM mice. We find that the cytotoxic CD4+ T cell population in GBM is increased due to synergy with anti-programmed cell death protein 1 (anti-PD-1) immune checkpoint inhibitors, but this effect depends upon HGD supplementation. Thus, we determine that HGD supplementation enhances anti-tumor immune responses in GBM mice through gut microbiota modulation and suggest that the role of HGD supplementation in GBM should be re-examined.

Ex vivo drug sensitivity screening predicts response to temozolomide in glioblastoma patients and identifies candidate biomarkers.

BACKGROUND: Patient-derived glioma stem-like cells (GSCs) have become the gold-standard in neuro-oncological research; however, it remains to be established whether loss of in situ microenvironment affects the clinically-predictive value of this model. We implemented a GSC monolayer system to investigate in situ-in vitro molecular correspondence and the relationship between in vitro and patient response to temozolomide (TMZ). METHODS: DNA/RNA-sequencing was performed on 56 glioblastoma tissues and 19 derived GSC cultures. Sensitivity to TMZ was screened across 66 GSC cultures. Viability readouts were related to clinical parameters of corresponding patients and whole-transcriptome data. RESULTS: Tumour DNA and RNA sequences revealed strong similarity to corresponding GSCs despite loss of neuronal and immune interactions. In vitro TMZ screening yielded three response categories which significantly correlated with patient survival, therewith providing more specific prediction than the binary MGMT marker. Transcriptome analysis identified 121 genes related to TMZ sensitivity of which 21were validated in external datasets. CONCLUSION: GSCs retain patient-unique hallmark gene expressions despite loss of their natural environment. Drug screening using GSCs predicted patient response to TMZ more specifically than MGMT status, while transcriptome analysis identified potential biomarkers for this response. GSC drug screening therefore provides a tool to improve drug development and precision medicine for glioblastoma.

Novel therapeutic strategies in glioma targeting glutamatergic neurotransmission.

High grade gliomas carry a poor prognosis despite aggressive surgical and adjuvant approaches including chemoradiotherapy. Recent studies have demonstrated a mitogenic association between neuronal electrical activity and glioma growth involving the PI3K-mTOR pathway. As the predominant excitatory neurotransmitter of the brain, glutamate signalling in particular has been shown to promote glioma invasion and growth. The concept of the neurogliomal synapse has been established whereby glutamatergic receptors on glioma cells have been shown to promote tumour propagation. Targeting glutamatergic signalling is therefore a potential treatment option in glioma. Antiepileptic medications decrease excess neuronal electrical activity and some may possess anti-glutamate effects. Although antiepileptic medications continue to be investigated for an anti-glioma effect, good quality randomised trial evidence is lacking. Other pharmacological strategies that downregulate glutamatergic signalling include riluzole, memantine and anaesthetic agents. Neuromodulatory interventions possessing potential anti-glutamate activity include deep brain stimulation and vagus nerve stimulation - this contributes to the anti-seizure efficacy of the latter and the possible neuroprotective effect of the former. A possible role of neuromodulation as a novel anti-glioma modality has previously been proposed and that hypothesis is extended to include these modalities. Similarly, the significant survival benefit in glioblastoma attributable to alternating electrical fields (Tumour Treating Fields) may be a result of disruption to neurogliomal signalling. Further studies exploring excitatory neurotransmission and glutamatergic signalling and their role in glioma origin, growth and propagation are therefore warranted.

Therapeutic Potential of Linearol in Combination with Radiotherapy for the Treatment of Glioblastoma In Vitro.

Glioblastoma is one of the most malignant and lethal forms of primary brain tumors in adults. Linearol, a kaurane diterpene isolated from different medicinal plants, including those of the genus Sideritis, has been found to possess significant anti-oxidant, anti-inflammatory and anti-microbial properties. In this study, we aimed to determine whether linearol could exhibit anti-glioma effects when given alone or in combination with radiotherapy in two human glioma cell lines, U87 and T98. Cell viability was examined with the Trypan Blue Exclusion assay, cell cycle distribution was tested with flow cytometry, and the synergistic effects of the combination treatment were analyzed with CompuSyn software. Linearol significantly suppressed cell proliferation and blocked cell cycle at the S phase. Furthermore, pretreatment of T98 cells with increasing linearol concentrations before exposure to 2 Gy irradiation decreased cell viability to a higher extent than linearol or radiation treatment alone, whereas in the U87 cells, an antagonistic relationship was observed between radiation and linearol. Moreover, linearol inhibited cell migration in both tested cell lines. Our results demonstrate for the first time that linearol is a promising anti-glioma agent and further studies are needed to fully understand the underlying mechanism of this effect.

Modulation of blood-brain tumor barrier for delivery of magnetic hyperthermia to brain cancer.

Glioblastoma (GBM) is the most invasive brain tumor and remains lack of effective treatment. The existence of blood-brain tumor barrier (BBTB) constitutes the greatest barrier to non-invasive delivery of therapeutic agents to tumors in the brain. Here, we propose a novel approach to specifically modulate BBTB and deliver magnetic hyperthermia in a systemic delivery mode for the treatment of GBM. BBTB modulation is achieved by targeted delivering fingolimod to brain tumor region via dual redox responsive PCL-SeSe-PEG (poly (ε-caprolactone)-diselenium-poly (ethylene glycol)) polymeric nanocarrier. As an antagonist of sphingosine 1-phosphate receptor-1 (S1P1), fingolimod potently inhibits the barrier function of BBB by blocking the binding of sphingosine 1-phosphate (S1P) to S1P1 in endothelial cells. We found that the modulated BBTB showed slight expression level of tight junction proteins, allowing efficient accumulation of zinc- and cobalt- doped iron oxide nanoclusters (ZnCoFe NCs) with enhanced magnetothermal conversion efficiency into tumor tissues through the paracellular pathway. As a result, the co-delivery of heat shock protein 70 inhibitor VER-155008 with ZnCoFe NCs could realize synergistic magnetic hyperthermia effects upon exposure to an alternating current magnetic field (ACMF) in both GL261 and U87 brain tumor models. This modulation approach brings new ideas for the treatment of central nervous system diseases that require delivery of therapeutic agents across the blood-brain barrier (BBB).

Endocannabinoids are potential inhibitors of glioblastoma multiforme proliferation.

Globally, it is evident that glioblastoma multiforme (GBM) is an aggressive malignant cancer with a high mortality rate and no effective treatment options. Glioblastoma is classified as the stage-four progression of a glioma tumor, and its diagnosis results in a shortened life expectancy. Treatment options for GBM include chemotherapy, immunotherapy, surgical intervention, and conventional pharmacotherapy; however, at best, they extend the patient's life by a maximum of 5 years. GBMs are considered incurable due to their high recurrence rate, despite various aggressive therapeutic approaches which can have many serious adverse effects. Ceramides, classified as endocannabinoids, offer a promising novel therapeutic approach for GBM. Endocannabinoids may enhance the apoptosis of GBM cells but have no effect on normal healthy neural cells. Cannabinoids promote atypical protein kinase C, deactivate fatty acid amide hydrolase enzymes, and activate transient receptor potential vanilloid 1 (TRPV1) and TRPV2 to induce pro-apoptotic signaling pathways without increasing endogenous cannabinoids. In previous in vivo studies, endocannabinoids, chemically classified as amide formations of oleic and palmitic acids, have been shown to increase the pro-apoptotic activity of human cancer cells and inhibit cell migration and angiogenesis. This review focuses on the biological synthesis and pharmacology of endogenous cannabinoids for the enhancement of cancer cell apoptosis, which have potential as a novel therapy for GBM. Please cite this article as: Duzan A, Reinken D, McGomery TL, Ferencz N, Plummer JM, Basti MM. Endocannabinoids are potential inhibitors of glioblastoma multiforme proliferation. J Integr Med. 2023; 21(2): 120-128.

Prediction of response to lomustine-based chemotherapy in glioma patients at recurrence using MRI and FET PET.

BACKGROUND: We evaluated O-(2-[18F]fluoroethyl)-l-tyrosine (FET) PET and MRI for early response assessment in recurrent glioma patients treated with lomustine-based chemotherapy. METHODS: Thirty-six adult patients with WHO CNS grade 3 or 4 gliomas (glioblastoma, 69%) at recurrence (median number of recurrences, 1; range, 1-3) were retrospectively identified. Besides MRI, serial FET PET scans were performed at baseline and early after chemotherapy initiation (not later than two cycles). Tumor-to-brain ratios (TBR), metabolic tumor volumes (MTV), the occurrence of new distant hotspots with a mean TBR >1.6 at follow-up, and the dynamic parameter time-to-peak were derived from all FET PET scans. PET parameter thresholds were defined using ROC analyses to predict PFS of ≥6 months and OS of ≥12 months. MRI response assessment was based on RANO criteria. The predictive values of FET PET parameters and RANO criteria were subsequently evaluated using univariate and multivariate survival estimates. RESULTS: After treatment initiation, the median follow-up time was 11 months (range, 3-71 months). Relative changes of TBR, MTV, and RANO criteria predicted a significantly longer PFS (all P ≤ .002) and OS (all P ≤ .045). At follow-up, the occurrence of new distant hotspots (n ≥ 1) predicted a worse outcome, with significantly shorter PFS (P = .005) and OS (P < .001). Time-to-peak changes did not predict a significantly longer survival. Multivariate survival analyses revealed that new distant hotspots at follow-up FET PET were most potent in predicting non-response (P < .001; HR, 8.578). CONCLUSIONS: Data suggest that FET PET provides complementary information to RANO criteria for response evaluation of lomustine-based chemotherapy early after treatment initiation.

Effect of Copper Chelators via the TGF-ß Signaling Pathway on Glioblastoma Cell Invasion.

Glioblastoma multiforme (GBM) is a fast-growing and aggressive type of brain cancer. Unlike normal brain cells, GBM cells exhibit epithelial-mesenchymal transition (EMT), which is a crucial biological process in embryonic development and cell metastasis, and are highly invasive. Copper reportedly plays a critical role in the progression of a variety of cancers, including brain, breast, and lung cancers. However, excessive copper is toxic to cells. D-penicillamine (DPA) and triethylenetetramine (TETA) are well-known copper chelators and are the mainstay of treatment for copper-associated diseases. Following treatment with copper sulfate and DPA, GBM cells showed inhibition of proliferation and suppression of EMT properties, including reduced expression levels of N-cadherin, E-cadherin, and Zeb, which are cell markers associated with EMT. In contrast, treatment with copper sulfate and TETA yielded the opposite effects in GBM. Genes, including TGF-ß, are associated with an increase in copper levels, implying their role in EMT. To analyze the invasion and spread of GBM, we used zebrafish embryos xenografted with the GBM cell line U87. The invasion of GBM cells into zebrafish embryos was markedly inhibited by copper treatment with DPA. Our findings suggest that treatment with copper and DPA inhibits proliferation and EMT through a mechanism involving TGF-ß/Smad signaling in GBM. Therefore, DPA, but not TETA, could be used as adjuvant therapy for GBM with high copper concentrations.

Integrative multi-omics approach to targeted therapy for glioblastoma.

This review describes recent technological advances applied to glioblastoma (GBM), a brain tumor with dismal prognosis. International consortial efforts suggest the presence of molecular subtypes within histologically identical GBM tumors. This emphasizes that future treatment decisions should no longer be made based solely on morphological analyses, but must now take into consideration such molecular and cellular heterogeneity. The use of single-cell technologies has advanced our understanding and assignation of functional subtypes revealing therapeutic vulnerabilities. Our team has developed stratification approaches in the past few years, and we have been able to identify patient cohorts enriched for various signaling pathways. Importantly, our Glioportal brain tumor resource has been established under the National Neuroscience Institute Tissue Bank in 2021. This resource offers preclinical capability to validate working hypotheses established from patient clinical datasets. This review highlights recent developments with the ultimate goal of assigning functional meaning to molecular subtypes, revealing therapeutic vulnerabilities.

Berberine and folic acid co-modified pH-sensitive cascade-targeted PTX-liposomes coated with Tween 80 for treating glioma.

Chemotherapy is a conventional treatment for glioma, but its efficacy is greatly limited due to low blood-brain barrier (BBB) permeability and lack of specificity. Herein, intelligent and tumor microenvironment (TME)-responsive folic acid (FA) derivatives and mitochondria-targeting berberine (BBR) derivatives co-modified liposome coated with Tween 80 loading paclitaxel (PTX-Tween 80-BBR + FA-Lip) was constructed. Specifically speaking, liposomes modified by FA can be effectively target ed to glioma cells. BBR, due to its delocalized positive electricity and lipophilicity, can be attracted by mitochondrial membrane potential and concentrate on mitochondria to achieve mitochondrial targeting and induce cell apoptosis. By simultaneously modifying the liposome with FA and BBR to deliver drugs, leads to a good therapeutic effect of glioma through FA-based glioma targeting and BBR-based mitochondrial targeting. In addition, the surface of the liposome was coated with Tween 80 to further improve BBB penetration. All results exhibited that PTX-Tween 80-BBR + FA-Lip can observably improve the chemotherapy therapeutic efficacy through the highly specific tumor targeting and mitochondrial targeting, which can provide new ideas and methods for the targeted therapy of glioma.

Cost Effectiveness of 18F-FET PET for Early Treatment Response Assessment in Glioma Patients After Adjuvant Temozolomide Chemotherapy.

In light of increasing health-care costs, higher medical expenses should be justified socioeconomically. Therefore, we calculated the effectiveness and cost effectiveness of PET using the radiolabeled amino acid O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) compared with conventional MRI for early identification of responders to adjuvant temozolomide chemotherapy. A recently published study in isocitrate dehydrogenase wild-type glioma patients suggested that 18F-FET PET parameter changes predicted a significantly longer survival already after 2 cycles whereas MRI changes were not significant. Methods: To determine the effectiveness and cost effectiveness of serial 18F-FET PET imaging, we analyzed published clinical data and calculated the associated costs from the perspective of the German Statutory Health Insurance system. Based on a decision-tree model, the effectiveness of 18F-FET PET and MRI was calculated-that is, the probability to correctly identify a responder as defined by an overall survival of at least 15 mo. To determine the cost effectiveness, the incremental cost effectiveness ratio (ICER) was calculated-that is, the cost for each additionally identified responder by 18F-FET PET who would have remained undetected by MRI. The robustness of the results was tested by deterministic and probabilistic Monte Carlo sensitivity analyses. Results: Compared with MRI, 18F-FET PET increased the rate of correctly identified responders to chemotherapy by 26%; thus, 4 patients needed to be examined by 18F-FET PET to identify 1 additional responder. Considering the respective costs for serial 18F-FET PET and MRI, the ICER resulted in €4,396.83 for each additional correctly identified responder by 18F-FET PET. Sensitivity analyses confirmed the robustness of the results. Conclusion: In contrast to conventional MRI, the model suggests that 18F-FET PET is cost-effective in terms of ICER values. Considering the high cost of temozolomide, the integration of 18F-FET PET has the potential to avoid premature chemotherapy discontinuation at reasonable cost.

ISL1 Promotes Human Glioblastoma-Derived Stem Cells' Self-Renewal by Activation of Sonic Hedgehog/GLI1 Function.

Glioblastoma (GBM), the most aggressive primary heterogeneous primary brain tumor, is a glioma subtype that originates from the glial cells of the central nervous system. Glioblastoma stem cells (GSCs), situated at the top of the hierarchy, initiate and maintain the tumor and are largely accountable for GBM resistance to the mainstay treatment and recurrence. The LIM homeobox transcription factor islet 1 (ISL1) induces tumorigenicity in various tumors; however, its function in GSCs has been less reported. We aimed to generate GSCs from surgical specimens of human GBM and investigate the effect of ISL1 knockdown on GSCs. We established patient-derived GSCs, determined cancer stem cell marker expression, and immunostained GSCs to assess cell viability and apoptosis. We demonstrated that ISL1 deletion decreased the GSC viability and proliferation, and upregulated apoptosis. Moreover, we performed enzyme-linked immunosorbent assay and western blotting and found that ISL1 knockdown affected the expression of sonic hedgehog (SHH) and its downstream regulator GLI1, and further validated these results by supplementing the cells with recombinant SHH. Our results suggested that ISL1 played a critical role in regulating GBM growth and that an ISL1/SHH/GLI1 pathway was required for the maintenance of GBM progression and malignancy. The regulation of GSC growth through ISL1 might be a mechanism of interest for future therapeutic studies.

Response of human glioblastoma cells to hyperthermia: Cellular apoptosis and molecular events.

Glioblastoma multiforme (GBM) also categorized as a grade IV astrocytoma, is an aggressive brain tumor which invades the surrounding brain tissue. Hyperthermia is known to be effective for chemo-radiotherapy to sensitize cancer cells to radiation as a treatment option for patients with GBM. The current study was performed in order to assess and compare the properties of the astrocyte and cancer stem cells isolated from glioblastoma exposed to hyperthermia. Astrocytes and cancer stem cells were isolated from human glioblastoma tissue. Glioblastoma tissues were digested and cultured in culture medium supplemented with B27, basic fibroblast growth factor and epidermal growth factor. The morphology and specific markers were evaluated in astrocyte and cancer stem cell of human glioblastoma through immunocytochemistry and quantitative real-time RT-PCR. The multipotentiality of cancer stem cells was presented using differentiation potential into neurons, oligodendrocytes, and astrocytes. For hyperthermia, cells were exposed to temperatures at 4246 °C for 1 h using a water bath. Cell survival rate by MTT assay and apoptosis using quantitative real-time RT-PCR and western blot were evaluated. Results demonstrated that there were two morphology types in cell culture including epithelioid morphology and fibroblastic morphology. Astrocytes were confirmed via expression of the Glial fibrillary acidic protein (GFAP) protein; whereas, cancer stem cells (CSCs) were round and floating in the culture medium. Immunocytochemical staining indicated that nestin, CD133 and SRY-box 2 (SOX2) antigens were positively expressed in primary neurospheres. Results indicated that cancer stem cells of glioblastoma are multipotent and are able to differentiate into neurons, oligodendrocytes, and astrocytes. The current study obtained evidence via apoptosis evaluation that CSCs are resistant to hyperthermia when compared to astrocytes isolated from glioblastoma. Furthermore, hyperthermia was demonstrated to decrease cell resistance, which may be effective for chemo-radiotherapy to sensitize cancer cells to radiation. Taken together, CSCs of glioblastoma could be used as a powerful tool for evaluating the tumorigenesis process in the brain and developing novel therapies for treatment of GBM.

Borneol and Tetrandrine Modulate the Blood-Brain Barrier and Blood-Tumor Barrier to Improve the Therapeutic Efficacy of 5-Fluorouracil in Brain Metastasis.

The efficacy of chemotherapeutic drugs for the treatment of brain metastasis may be compromised by the blood-brain barrier (BBB) and blood-tumor barrier (BTB). P-glycoprotein (P-gp) is a multidrug resistance protein that potentially limits the penetration of chemotherapeutics through the BBB and BTB. 5-Fluorouracil (5-FU) is widely used to treat cancer. Bioactive constituents of medicinal herbs, such as borneol and tetrandrine, potentially improve drug penetration through the BBB and BTB. We hypothesized that borneol and tetrandrine might modulate the BBB and BTB to enhance 5-FU penetration into the brain. To investigate this, in vitro and in vivo models were developed to explore the modulatory effects of borneol and tetrandrine on 5-FU penetration through the BBB and BTB. In the in vitro models, barrier integrity, cell viability, barrier penetration, P-gp activity, and NF-κB expression were assessed. In the in vivo brain metastasis models, cancer cells were injected into the internal carotid artery to evaluate tumor growth. The experimental results demonstrated that borneol and borneol + tetrandrine reduced BBB integrity. The efflux pump function of P-gp was partially inhibited by tetrandrine and borneol + tetrandrine. In the in vivo experiment, borneol + tetrandrine effectively prolonged survival without compromising body weight. In conclusion, BBB and BTB integrity was modulated by borneol and borneol + tetrandrine. The combination of borneol and tetrandrine could be used to improve the chemotherapeutic control of brain metastasis.

From GWAS to drug screening: repurposing antipsychotics for glioblastoma.

BACKGROUND: Glioblastoma is currently an incurable cancer. Genome-wide association studies have demonstrated that 41 genetic variants are associated with glioblastoma and may provide an option for drug development. METHODS: We investigated FDA-approved antipsychotics for their potential treatment of glioblastoma based on genome-wide association studies data using a 'pathway/gene-set analysis' approach. RESULTS: The in-silico screening led to the discovery of 12 candidate drugs. DepMap portal revealed that 42 glioma cell lines show higher sensitivities to 12 candidate drugs than to Temozolomide, the current standard treatment for glioblastoma. CONCLUSION: In particular, cell lines showed significantly higher sensitivities to Norcyclobenzaprine and Protriptyline which were predicted to bind targets to disrupt a certain molecular function such as DNA repair, response to hormones, or DNA-templated transcription, and may lead to an effect on survival-related pathways including cell cycle arrest, response to ER stress, glucose transport, and regulation of autophagy. However, it is recommended that their mechanism of action and efficacy are further determined.

Quiescent human glioblastoma cancer stem cells drive tumor initiation, expansion, and recurrence following chemotherapy.

We test the hypothesis that glioblastoma harbors quiescent cancer stem cells that evade anti-proliferative therapies. Functional characterization of spontaneous glioblastomas from genetically engineered mice reveals essential quiescent stem-like cells that can be directly isolated from tumors. A derived quiescent cancer-stem-cell-specific gene expression signature is enriched in pre-formed patient GBM xenograft single-cell clusters that lack proliferative gene expression. A refined human 118-gene signature is preserved in quiescent single-cell populations from primary and recurrent human glioblastomas. The F3 cell-surface receptor mRNA, expressed in the conserved signature, identifies quiescent tumor cells by antibody immunohistochemistry. F3-antibody-sorted glioblastoma cells exhibit stem cell gene expression, enhance self-renewal in culture, drive tumor initiation and serial transplantation, and reconstitute tumor heterogeneity. Upon chemotherapy, the spared cancer stem cell pool becomes activated and accelerates transition to proliferation. These results help explain conventional treatment failure and lay a conceptual framework for alternative therapies.

A novel biguanide (IM1761065) inhibits bioenergetics of glioblastoma tumorspheres.

PURPOSE: Glioblastoma (GBM) is a rapidly growing tumor in the central nervous system with altered metabolism. Depleting the bioenergetics of tumors with biguanides have been suggested as an effective therapeutic approach for treating GBMs. The purpose of this study was to determine the effects of IM1761065, a novel biguanide with improved pharmacokinetics, on GBM-tumorspheres (TSs). METHODS: The biological activities of IM1761065 on GBM-TSs, including their effects on viability, ATP levels, cell cycle, stemness, invasive properties, and transcriptomes were examined. The in vivo efficacy of IM1761065 was tested in a mouse orthotopic xenograft model. RESULTS: IM1761065 decreased the viability and ATP levels of GBM-TSs in a dose-dependent manner, and reduced basal and spare respiratory capacity in patient-derived GBM-TS, as measured by the oxygen consumption rate. Sphere formation, expression of stemness-related proteins, and invasive capacity of GBM-TSs were also significantly suppressed by IM1761065. A gene-ontology comparison of IM1761065-treated groups showed that the expression levels of stemness-related, epithelial mesenchymal transition-related, and mitochondrial complex I genes were also significantly downregulated by IM1761065. An orthotopic xenograft mouse model showed decreased bioluminescence in IM1761065-treated cell-injected mice at 5 weeks. IM1761065-treated group showed longer survival than the control group (P = 0.0289, log-rank test). CONCLUSION: IM1761065 is a potent inhibitor of oxidative phosphorylation. The inhibitory effect of IM1761065 on the bioenergetics of GBM-TS suggests that this novel compound could be used as a new drug for the treatment of GBM.