Consensus guidelines for the management of adult low-grade gliomas for low and middle-income countries.

Low-grade gliomas (LGG) are brain tumors of glial cells origin. They are grade 1 and grade 2 tumors according to the WHO classification. Diagnosis of LGG is made through imaging, histopathological analysis, and use of molecular markers. Imaging alone does not establish the grade of the tumor and thus a histopathological examination of tissue is crucial in establishing the definite histopathological diagnosis. Clinical presentation varies according to the location and size of the tumor. Surgical resection is strongly recommended in LGG over observation to improve overall survival as surgery leads to greater benefit due to progression-free survival. Radiation has shown benefits in LGG patients in randomized controlled trials and chemotherapy with temozolomide has also shown good results. This paper covers the principles of low-grade gliomas management and summarizes the recommendations for the LMICs.

AB045. E2F6 promotes temozolomide resistance in glioblastoma by enrichment in CARD6 and POSTN promoter region.

BACKGROUND: Glioblastoma (GBM) is the most aggressive primary malignant brain tumor. Temozolomide (TMZ) is the most used first-line chemotherapeutic agent for GBM after surgery, but acquired resistance to TMZ frequently leads to treatment failure and is a major challenge in the clinical treatment of GBM. Increasing evidence suggests that E2F transcription factor 6 (E2F6) is associated with a variety of tumor malignant biological behaviors and drug resistance, but its biological function and underlying molecular mechanisms in GBM are unknown. METHODS: The study investigated the levels of E2F6 in both TMZ-sensitive and TMZ-resistant GBM cells and tissues using Western blotting and immunofluorescence assays. In vitro experiments were conducted to explore the impact of E2F6 on TMZ resistance and glioma stem cell stemness. These experiments included Western blotting, colony formation assay, flow cytometry assay, and TdT-mediated dUTP nick-end labeling (TUNEL) assay. Bioinformatic analyses were conducted to investigate the mechanism behind the high expression of E2F6 in TMZ-resistant cells and its correlation with caspase recruitment domain 6 (CARD6) and disulfide-linked cell adhesion protein (POSTN). The study employed bioinformatic analyses, messenger RNA (mRNA) sequencing, chromatin immunoprecipitation sequencing assay, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. To examine the function of E2F6, an intracranial xenograft tumor mouse model was used for in vivo experiments. RESULTS: It was found that CARD6 and POSTN were significantly associated with TMZ resistance and survival of GBM patients. E2F6 was up-regulated in TMZ-resistant cells and tissues. Knockdown of E2F6 down-regulated the expression of CARD6, promoted TMZ-induced apoptosis, and enhanced chemo-sensitivity, whereas its overexpression significantly increased TMZ resistance in vitro and in vivo. In addition, E2F6 can promote TMZ resistance through stem-like properties acquisition. We identified a signaling pathway related to E2F6 and POSTN, which maintains the self-renewal of GBM stem cells (GSCs). E2F6 concentrates in the promoter region of POSTN, thereby regulating the expression of GSCs-related genes cluster of differentiation 133 (CD133), Nestin, and sex-determining region Y-box 2 (SOX2), which may be involved in tumor metabolism and drug resistance processes. Down-regulation of E2F6 down-regulated the expression of POSTN and inhibited tumor growth in nude mice. CONCLUSIONS: These results suggest that the E2F6-CARD6/POSTN signaling axis regulates the malignant biological behaviors of GBM and TMZ resistance. These findings are expected to provide promising therapeutic targets for CARD6 overcoming GBM TMZ resistance.

AB071. Predictive value of plasma microRNA-10b and microRNA-21 on chemotherapy toxicity, recurrence, and overall survival in high-grade glioma patients treated with temozolomide.

BACKGROUND: The low level of median survival rate after complete therapy (i.e., surgery and concomitant chemotherapy and radiotherapy) in high-grade glioma (HGG) patients reflects the needs for a better understanding about HGG pathogenesis, including the role of epigenetic in glioma. MicroRNA (miRNA), a small chain non-coding RNA, has been increasingly utilized in the management of other oncology cases and might possess an immense potential in HGG. The expression of miRNA-10b and miRNA-21 (i.e., two miRNAs that are frequently studied due to its involvement in glioma) are higher in HGG patients and their role in regulatory mechanism of glioma has been established. However, the influence of those miRNAs in toxicity, recurrence, and overall survival of HGG patients is still unclear. We aim to assess the predictive value of plasma miRNA-10b and miRNA-21 in the chemotherapy toxicity, recurrence, and overall survival of HGG patients. METHODS: This is an observational analytic study using hospital-based mixed cohort approach. The study is conducted in RSUP Dr. Sardjito, Yogyakarta, from January 2021 to December 2024. We prospectively assess the plasma miRNA level from HGG patients who met the inclusive and exclusive criteria. The consecutive sampling is used until the sample size is met. Statistical analysis will be conducted for temozolomide toxicity using Spearman's rank correlation, for recurrence using logistical regression, and for overall survival test. RESULTS: In this ongoing study, we plan to collect samples from 155 HGG patients. As of April 2024, we managed to collect 96 samples (median age of 49 years and 55% of male patients). Most of the patients were diagnosed with World Health Organization (WHO) grade IV tumors (69.3%), with the most common diagnosis was glioblastoma (62%). Most of the patients had unmethylated O6-methylguanine-DNA methyltransferase (MGMT) and wild-type isocitrate dehydrogenase (IDH) status (62% and 57%, respectively). There was no difference in miRNA-21 expression based on MGMT status (methylated or unmethylated), nor IDH status (wild type or mutant), with P=0.39 and P=0.25, respectively. Moreover, we found no significant difference in miRNA-10b expression in both MGMT status and both IDH status (P=0.19 and P=0.09). As for the data regarding toxicity, recurrence, and overall survival was still on the process of data collection. CONCLUSIONS: MiRNA is a promising epigenetic modulator that might be utilized in HGG management. A better understanding on the role of miRNA in HGG patients might be able to improve clinical outcome.

AB002. DNA methylation-regulated genes contribute to temozolomide (TMZ) resistance by scaffolding paraspeckle proteins.

BACKGROUND: Temozolomide (TMZ) resistance in glioblastoma (GBM) remains a challenge in clinical treatment and the mechanism is largely unknown. Emerging evidence shows that epigenetic modifications including DNA methylation and non-coding RNA were involved in diverse biological processes, including therapeutic resistance. However, the underlying mechanisms by which DNA methylation-mediated non-coding RNA regulates TMZ resistance remain poorly characterized. METHODS: RNA microarray and DNA methylation chips of TMZ-resistant and parental GBM cells were performed for the gain of unreported long non-coding RNA HSD52. Quantitative reverse transcription polymerase chain reaction (PCR) and fluorescence in situ hybridization assays were used to detect HSD52 levels in GBM cells and tissues. The investigation into HSD52's impact on TMZ resistance was conducted utilizing both in vitro assays and intracranial xenograft mouse models. The mechanism of HSD52 expression and its relationships with paraspeckle proteins, non-POU domain-containing octamer-binding protein (NONO) and splicing factor proline/glutamine rich (SFPQ), as well as alpha-thalassemia mental retardation X-linked (ATRX) mRNA were determined by pyrosequencing assay, chromatin immunoprecipitation, chromatin isolation by RNA purification, RNA immunoprecipitation, RNA pulldown, immunofluorescence, and western blot assays. RESULTS: HSD52 was highly expressed in high-grade glioma and TMZ-resistant GBM cells. Phosphorylated p38 mitogen-activated protein kinase (p38 MAPK)/ubiquitin specific peptidase 7 (USP7) axis mediates H3 ubiquitination, impairs the interaction between H3K23ub and DNA methyltransferase 1 (DNMT1) and the recruitment of DNMT1 at the HSD52 promoter to attenuate DNA methylation, which makes the transcription factor 12 (TCF12) more accessible to the promoter region to regulate HSD52 expression. Further analysis showed that HSD52 can serve as a scaffold to promote the interaction between NONO and SFPQ, and then increase the paraspeckle assembly and activate the paraspeckle/ataxia telangiectasia mutated (ATM) kinase pathway in GBM cells. In addition, HSD52 forms an RNA-RNA duplex with ATRX mRNA, and facilitates the association of heteromer of SFPQ and NONO with RNA duplex, thus leading to the increase of ATRX mRNA stability and level. In clinical patients, HSD52 is required for TMZ resistance and GBM recurrence. CONCLUSIONS: Our results reveal that HSD52 in GBM could serve as a therapeutic target to overcome TMZ resistance, enhancing the clinical benefits of TMZ chemotherapy.

Bevacizumab Alone Versus Bevacizumab Plus Irinotecan in Patients With Recurrent Glioblastoma: A Nationwide Population-Based Study.

BACKGROUND: For treating recurrent glioblastoma, for which there is no established treatment, the antiangiogenic antibody, bevacizumab, is used alone or with irinotecan. This study was aimed at comparing the survival of patients with recurrent glioblastoma receiving bevacizumab monotherapy and those receiving bevacizumab plus irinotecan combination therapy (B+I) by using a nationwide population-based dataset. METHODS: Patients matching the International Classification of Diseases code C71.x were screened from the Health Insurance Review and Assessment Service database. From January 2008 to November 2021, patients who underwent surgery or biopsy and subsequent standard concurrent chemoradiation with temozolomide were included. Among them, those who received bevacizumab monotherapy or B+I were selected. Demographic characteristics, inpatient stay, prescription frequency, survival outcomes, and steroid prescription duration were compared between these two groups. RESULTS: Eight hundred and forty-six patients who underwent surgery or biopsy and received concurrent chemoradiotherapy with temozolomide were included. Of these, 450 and 396 received bevacizumab monotherapy and B+I, respectively. The corresponding median overall survival from the initial surgery was 22.60 months (95% confidence interval [CI], 20.50-24.21) and 20.44 months (95% CI, 18.55-22.60; P = 0.508, log-rank test). The B+I group had significantly more bevacizumab prescriptions (median 5 times; BEV group: median 3 times). Cox analysis, based on the postsurgery period, revealed that male sex (hazard ratio [HR], 1.28; P = 0.002), older age (HR, 1.01; P = 0.042), and undergoing biopsy instead of surgery (HR, 1.79; P < 0.0001) were significantly associated with decreased survival. Fewer radiotherapy cycles correlated with improved survival outcomes (HR, 0.63; P = 0.001). Cox analysis, conducted from the start of chemotherapy including bevacizumab, showed that male sex was the only variable significantly associated with decreased survival (HR, 1.18; P = 0.044). CONCLUSION: We found no significant difference in overall survival between the bevacizumab monotherapy and B+I groups. Considering the additional potential toxicity associated with irinotecan, bevacizumab monotherapy could be a suitable treatment option for treating recurrent glioblastoma.

Mechanistic Insights on Metformin and Arginine Implementation as Repurposed Drugs in Glioblastoma Treatment.

As the most common and aggressive primary malignant brain tumor, glioblastoma is still lacking a satisfactory curative approach. The standard management consisting of gross total resection followed by radiotherapy and chemotherapy with temozolomide only prolongs patients' life moderately. In recent years, many therapeutics have failed to give a breakthrough in GBM treatment. In the search for new treatment solutions, we became interested in the repurposing of existing medicines, which have established safety profiles. We focused on the possible implementation of well-known drugs, metformin, and arginine. Metformin is widely used in diabetes treatment, but arginine is mainly a cardiovascular protective drug. We evaluated the effects of metformin and arginine on total DNA methylation, as well as the oxidative stress evoked by treatment with those agents. In glioblastoma cell lines, a decrease in 5-methylcytosine contents was observed with increasing drug concentration. When combined with temozolomide, both guanidines parallelly increased DNA methylation and decreased 8-oxo-deoxyguanosine contents. These effects can be explained by specific interactions of the guanidine group with m5CpG dinucleotide. We showed that metformin and arginine act on the epigenetic level, influencing the foreground and potent DNA regulatory mechanisms. Therefore, they can be used separately or in combination with temozolomide, in various stages of disease, depending on desired treatment effects.

Use of surface-modified porous silicon nanoparticles to deliver temozolomide with enhanced pharmacokinetic and therapeutic efficacy for intracranial glioblastoma in mice.

Glioblastoma (GBM) is one of the most common and fatal primary brain tumors, with a 5-year survival rate of 7.2%. The standard treatment for GBM involves surgical resection followed by chemoradiotherapy, and temozolomide (TMZ) is currently the only approved chemotherapeutic agent for the treatment of GBM. However, hydrolytic instability and insufficient drug accumulation are major challenges that limit the effectiveness of TMZ chemotherapy. To overcome these limitations, we have developed a drug delivery platform utilizing porous silicon nanoparticles (pSiNPs) to improve the stability and blood-brain barrier penetration of TMZ. The pSiNPs are synthesized via electrochemical etching and functionalized with octadecane. The octadecyl-modified pSiNP (pSiNP-C18) demonstrates the superiority of loading efficiency, in vivo stability, and brain accumulation of TMZ. Treatment of intracranial tumor-bearing mice with TMZ-loaded pSiNP-C18 results in a decreased tumor burden and a corresponding increase in survival compared with equivalent free-drug dosing. Furthermore, the mice treated with TMZ-loaded nanoparticles do not exhibit in vivo toxicity, thus underscoring the preclinical potential of the pSiNP-based platform for the delivery of therapeutic agents to gliomas.

Gastrodin Liposomes Block Crosstalk between Astrocytes and Glioma Cells via Downregulating Cx43 to Improve Antiglioblastoma Efficacy of Temozolomide.

The crosstalk between glioma cells and astrocytes plays a crucial role in developing temozolomide (TMZ) resistance of glioblastomas, together with the existence of the BBB contributing to the unsatisfactory clinical treatment of glioblastomas. Herein, we developed a borneol-modified and gastrodin-loaded liposome (Bo-Gas-LP), with the intent of enhancing the efficacy of TMZ therapy after intranasal administration. The results showed that Bo-Gas-LP improved GL261 cells' sensitivity to TMZ and prolonged survival of GL261-bearing mice by blocking the crosstalk between astrocytes and glioblastoma cells with the decrease of Cx43. Our study showed that intranasal Bo-Gas-LP targeting the crosstalk in glioblastoma microenvironments proposed a promising targeted therapy idea to overcome the current therapeutic limitations of TMZ-resistant glioblastomas.

Clinical improvement of diffuse intrinsic pontine glioma treated with radiation therapy concurrent with temozolomide: A case report.

Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive paediatric brain tumour and nowadays has not had satisfactory result, with most patients do not survive within 1 year of diagnosis. Due to its proximity to critical organs, surgery is avoided, and radiation is the mainstay of treatment. In this case report, we present a case of DIPG treated with radiation and concurrent temozolomide. A 7- year-old child was admitted with complaints of weakness in the eyelid, upper and lower limbs 2 months ago. Physical examination showed tetra paresis and bilateral cranial nerve palsy. Magnetic resonance imaging (MRI) scan showed intracranial tumour consistent with DIPG. Diagnosis was made based on imaging as surgery or biopsy can lead to further morbidity. The patient underwent radiotherapy with concurrent chemotherapy of temozolomide. Radiation was given by dose of 54 Gy/30 fractions (30 × 1.8 Gy) with volumetric arc therapy (VMAT). Due to technical issue after the first five irradiations resulting in 2 weeks delay, boosting of dose by 5 × 1.8 Gy was then given, hence, the total dose was 63 Gy. The booster only targeted the gross tumour volume. Following radiation, the patient felt clinical improvement. Eyelid and limb movement improved since the 15th fraction. At the last fraction, the patient's condition improved symptomatically, but experienced complaints related to post radiation oedema including dizziness and nausea. These complaints were improved upon steroids administration. The MRI evaluation will be done after 8 to 12 weeks of radiation, considering the effects of acute radiation could still occur at this period. In conclusion, a combination of radiotherapy and temozolomide could be an option for DIPG management, with tolerable acute toxicity and possible clinical improvements.

First step results from a phase II study of a dendritic cell vaccine in glioblastoma patients (CombiG-vax).

Background: Glioblastoma (GBM) is a poor prognosis grade 4 glioma. After surgical resection, the standard therapy consists of concurrent radiotherapy (RT) and temozolomide (TMZ) followed by TMZ alone. Our previous data on melanoma patients showed that Dendritic Cell vaccination (DCvax) could increase the amount of intratumoral-activated cytotoxic T lymphocytes. Methods: This is a single-arm, monocentric, phase II trial in two steps according to Simon's design. The trial aims to evaluate progression-free survival (PFS) at three months and the safety of a DCvax integrated with standard therapy in resected GBM patients. DCvax administration begins after completion of RT-CTwith weekly administrations for 4 weeks, then is alternated monthly with TMZ cycles. The primary endpoints are PFS at three months and safety. One of the secondary objectives is to evaluate the immune response both in vitro and in vivo (DTH skin test). Results: By December 2022, the first pre-planned step of the study was concluded with the enrollment, treatment and follow up of 9 evaluable patients. Two patients had progressed within three months after leukapheresis, but none had experienced DCvax-related G3-4 toxicities Five patients experienced a positive DTH test towards KLH and one of these also towards autologous tumor homogenate. The median PFS from leukapheresis was 11.3 months and 12.2 months from surgery. Conclusions: This combination therapy is well-tolerated, and the two endpoints required for the first step have been achieved. Therefore, the study will proceed to enroll the remaining 19 patients. (Eudract number: 2020-003755-15 https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-003755-15/IT).

A Systematic Review and Meta-Analysis on the Effectiveness of Radiotherapy and Temozolomide Treatment With or Without Bevacizumab in Patients With Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most frequent primary brain malignancy in adults. Despite improvements in imaging and therapy, the prognosis remains poor. To evaluate and compare the impact of combining bevacizumab with temozolomide and radiotherapy on progression-free survival (PFS) and overall survival (OS) in patients diagnosed with GBM. A comprehensive search was conducted across multiple databases, including PubMed, Embase, Scopus, and The Cochrane Library, covering the period from their inception to December 2022. The collected data underwent analysis employing appropriate statistical methods. Six articles were included in this systematic review and meta-analysis. The addition of bevacizumab to the combination of temozolomide/radiotherapy did not increase the OS in GBM patients. The pooled odds ratio (OR) was 0.843 (95% CI: 0.615-1.156, P = 0.290). The addition of bevacizumab to radiotherapy/temozolomide did not increase the PFS in patients with GBM. The pooled OR was 0.829 (95% CI: 0.561-1.224, P = 0.346). The funnel plot demonstrated the absence of the alleged pleiotropic effects by showing no evidence of observable variability across the estimations. This study does not support the benefit of the addition of bevacizumab to temozolomide and radiotherapy in improving OS and PFS in GBM patients.

Design and Synthesis of 7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic Acid Derivatives as PP5 Inhibitors To Reverse Temozolomide Resistance in Glioblastoma Multiforme.

The serine/threonine phosphatase family is important in tumor progression and survival. Due to the high conserved catalytic domain, designing selective inhibitors is challenging. Herein, we obtained compound 28a with 38-fold enhanced PP5 selectivity (PP2A/5 IC50 = 33.8/0.9 µM) and improved drug-like properties (favorable stability and safety, F = 82.0%) by rational drug design based on a phase II PP2A/5 dual target inhibitor LB-100. Importantly, we found the spatial conformational restriction of the 28a indole fragment was responsible for the selectivity of PP5. Thus, 28a activated p53 and downregulated cyclin D1 and MGMT, which showed potency in cell cycle arrest and reverse temozolomide (TMZ) resistance in the U87 MG cell line. Furthermore, oral administration of 28a and TMZ was well tolerated to effectively inhibit tumor growth (TGI = 87.7%) in the xenograft model. Collectively, these results implicate 28a could be a drug candidate by reversing TMZ resistance with a selective PP5 inhibition manner.

Triggering of endoplasmic reticulum stress via ATF4-SPHK1 signaling promotes glioblastoma invasion and chemoresistance.

Despite advances in therapies, glioblastoma (GBM) recurrence is almost inevitable due to the aggressive growth behavior of GBM cells and drug resistance. Temozolomide (TMZ) is the preferred drug for GBM chemotherapy, however, development of TMZ resistance is over 50% cases in GBM patients. To investigate the mechanism of TMZ resistance and invasive characteristics of GBM, analysis of combined RNA-seq and ChIP-seq was performed in GBM cells in response to TMZ treatment. We found that the PERK/eIF2α/ATF4 signaling was significantly upregulated in the GBM cells with TMZ treatment, while blockage of ATF4 effectively inhibited cell migration and invasion. SPHK1 expression was transcriptionally upregulated by ATF4 in GBM cells in response to TMZ treatment. Blockage of ATF4-SPHK1 signaling attenuated the cellular and molecular events in terms of invasive characteristics and TMZ resistance. In conclusion, GBM cells acquired chemoresistance in response to TMZ treatment via constant ER stress. ATF4 transcriptionally upregulated SPHK1 expression to promote GBM cell aggression and TMZ resistance. The ATF4-SPHK1 signaling in the regulation of the transcription factors of EMT-related genes could be the underlying mechanism contributing to the invasion ability of GBM cells and TMZ resistance. ATF4-SPHK1-targeted therapy could be a potential strategy against TMZ resistance in GBM patients.

Integrative single-cell and bulk transcriptome analyses identify a distinct pro-tumor macrophage signature that has a major prognostic impact on glioblastomas.

Glioblastoma (GBM) is a highly heterogeneous disease with poor clinical outcomes. To comprehensively dissect the molecular landscape of GBM and heterogeneous macrophage clusters in the progression of GBM, this study integrates single-cell and bulk transcriptome data to recognize a distinct pro-tumor macrophage cluster significantly associated with the prognosis of GBM and develop a GBM prognostic signature to facilitate prior subtypes. Leveraging glioma single-cell sequencing data, we identified a novel pro-tumor macrophage subgroup, marked by S100A9, which might interact with endothelial cells to facilitate tumor progression via angiogenesis. To further benefit clinical application, a prognostic signature was established with the genes associated with pro-tumor macrophages. Patients classified within the high-risk group characterized with enrichment in functions related to tumor progression, including epithelial-mesenchymal transition and hypoxia, displays elevated mutations in the TERT promoter region, reduced methylation in the MGMT promoter region, poorer prognoses, and diminished responses to temozolomide therapy, thus effectively discriminating between the prognostic outcomes of GBM patients. Our research sheds light on the intricate microenvironment of gliomas and identifies potential molecular targets for the development of novel therapeutic approaches.

Perception of pneumocystis jirovecii pneumonia (PJP) prophylaxis in glioma patients receiving concurrent temozolomide and radiation- a patient and physician survey.

PURPOSE: Pneumocystis jirovecii pneumonia (PJP) prophylaxis is required by provincial and national drug monographs during glioma treatment using temozolomide (TMZ) concurrently with radiation (TMZ-RT). However, real-world data suggest the potential benefits of PJP prophylaxis may not outweigh its potential harms in this population. METHODS: We conducted a single-center patient survey and a national physician survey to explore the role of PJP prophylaxis amongst glioma patients undergoing TMZ-RT. RESULTS: 23% (31/133) of physicians and 60% (44/73) of patients completed a survey. The median patient age was 42 (range 20-77); 85% (34/40) had completed adjuvant TMZ. Although only 2.4% (1/41) of patients received PJP prophylaxis, only one person (without PJP prophylaxis) was hospitalized for pneumonia. When presented with hypothetical PJP risks, 13.2% (5/38) of patients were concerned about PJP infection, while 26% (10/38) were concerned about potential side effects from prophylactic antibiotics. Most physicians (77%, 17/22) perceived the evidence for PJP prophylaxis as weak; 58% (11/19) did not routinely prescribe prophylaxis, and 73% (16/22) felt that PJP prophylaxis should be limited to patients with additional risk factors. Over 95% of physicians estimated that the incidence of PJP was < 1% in their last 5 years of practice regardless of PJP prophylaxis. For 73% (16/22) of physicians, to prescribe PJP prophylaxis, the risk of PJP infection needed to be 3-8%. CONCLUSION: The current recommendation to routinely prescribe PJP prophylaxis in patients receiving TMZ-RT in the absence of other risk factors warrants reconsideration.

Modelling glioblastoma resistance to temozolomide. A mathematical model to simulate cellular adaptation in vitro.

Drug resistance is one of the biggest challenges in the fight against cancer. In particular, in the case of glioblastoma, the most lethal brain tumour, resistance to temozolomide (the standard of care drug for chemotherapy in this tumour) is one of the main reasons behind treatment failure and hence responsible for the poor prognosis of patients diagnosed with this disease. In this work, we combine the power of three-dimensional in vitro experiments of treated glioblastoma spheroids with mathematical models of tumour evolution and adaptation. We use a novel approach based on internal variables for modelling the acquisition of resistance to temozolomide that was observed in experiments for a group of treated spheroids. These internal variables describe the cell's phenotypic state, which depends on the history of drug exposure and affects cell behaviour. We use model selection to determine the most parsimonious model and calibrate it to reproduce the experimental data, obtaining a high level of agreement between the in vitro and in silico outcomes. A sensitivity analysis is carried out to investigate the impact of each model parameter in the predictions. More importantly, we show how the model is useful for answering biological questions, such as what is the intrinsic adaptation mechanism, or for separating the sensitive and resistant populations. We conclude that the proposed in silico framework, in combination with experiments, can be useful to improve our understanding of the mechanisms behind drug resistance in glioblastoma and to eventually set some guidelines for the design of new treatment schemes.

Functional prediction of response to therapy prior to therapeutic intervention is associated with improved survival in patients with high-grade glioma.

Patients with high-grade glioma (HGG) have an extremely poor prognosis compounded by a lack of advancement in clinical care over the past few decades. Regardless of classification, most newly diagnosed patients receive the same treatment, radiation and temozolomide (RT/TMZ). We developed a functional precision oncology test that prospectively identifies individual patient's response to this treatment regimen. Tumor tissues isolated from patients with newly diagnosed HGG enrolled in 3D PREDICT REGISTRY were evaluated for response to chemotherapeutic agents using the 3D Predict™ Glioma test. Patients receiving RT/TMZ were followed for 2 years. Clinical outcomes including imaging, assessments, and biomarker measurements were compared to patient matched test-predicted therapy response. Median survival between test-predicted temozolomide responders and test-predicted temozolomide non-responders revealed a statistically significant increase in progression-free survival when using the test to predict response across multiple subgroups including HGG (5.8 months), glioblastoma (4.7 months), and MGMT unmethylated glioblastoma (4.7 months). Overall survival was also positively separated across the subgroups at 7.6, 5.1, and 6.3 months respectively. The strong correlation of 3D Predict Glioma test results with clinical outcomes demonstrates that this functional test is prognostic in patients treated with RT/TMZ and supports aligning clinical treatment to test-predicted response across varying HGG subgroups.

Importance of Autophagy Regulation in Glioblastoma with Temozolomide Resistance.

Glioblastoma (GBM) is the most aggressive and common malignant and CNS tumor, accounting for 47.7% of total cases. Glioblastoma has an incidence rate of 3.21 cases per 100,000 people. The regulation of autophagy, a conserved cellular process involved in the degradation and recycling of cellular components, has been found to play an important role in GBM pathogenesis and response to therapy. Autophagy plays a dual role in promoting tumor survival and apoptosis, and here we discuss the complex interplay between autophagy and GBM. We summarize the mechanisms underlying autophagy dysregulation in GBM, including PI3K/AKT/mTOR signaling, which is most active in brain tumors, and EGFR and mutant EGFRvIII. We also review potential therapeutic strategies that target autophagy for the treatment of GBM, such as autophagy inhibitors used in combination with the standard of care, TMZ. We discuss our current understanding of how autophagy is involved in TMZ resistance and its role in glioblastoma development and survival.