Celecoxib reverses the glioblastoma chemo-resistance to temozolomide through mitochondrial metabolism

Serendipity in Neuro-Oncology: The Evolution of Chemotherapeutic Agents

The development of novel therapeutics in neuro-oncology faces significant challenges, often marked by high costs and low success rates. Despite advances in molecular biology and genomics, targeted therapies have had limited impact on improving patient outcomes in brain tumors, particularly gliomas, due to the complex, multigenic nature of these malignancies. While significant efforts have been made to design drugs that target specific signaling pathways and genetic mutations, the clinical success of these rational approaches remains sparse. This review critically examines the landscape of neuro-oncology drug discovery, highlighting instances where serendipity has led to significant breakthroughs, such as the unexpected efficacy of repurposed drugs and off-target effects that proved beneficial. By exploring historical and contemporary cases, we underscore the role of chance in the discovery of impactful therapies, arguing that embracing serendipity alongside rational drug design may enhance future success in neuro-oncology drug development.

Tinostamustine (EDO-S101) and Its Combination with Celecoxib or Temozolomide as a Therapeutic Option for Adult-Type Diffuse Gliomas

Adult-type diffuse gliomas are characterized by inevitable recurrence and very poor prognosis. Novel treatment options, including multimodal drugs or effective drug combinations, are therefore eagerly awaited. Tinostamustine is an alkylating and histone deacetylase inhibiting molecule with great potential in cancer treatment. Thus, the aim of this study was to investigate its effects on glioma cells. In this context, tinostamustine was evaluated in monotherapy and as a combination therapy, with either celecoxib or temozolomide; additionally, the results were compared to the golden glioma chemotherapy standard-temozolomide. Our experiments, conducted on both temozolomide-sensitive U-87 MG astrocytoma and temozolomide-resistant U-138 MG glioblastoma cells revealed that tinostamustine and its combination with either celecoxib or temozolomide exert dose-dependent cytotoxicity, cause cell cycle arrest, induce oxidative stress-mediated apoptosis of malignant glioma cells, and mitigate their migratory potential. Astrocytoma cells were more susceptible to the tested treatments than glioblastoma cells, and, generally, those dual therapies were superior in anti-glioma efficacy compared to temozolomide. Overall, our study provides evidence that tinostamustine and the combination therapies consisting of tinostamustine and celecoxib or tinostamustine and temozolomide may represent a new approach for the effective treatment of malignant gliomas.

Valproic Acid and Celecoxib Enhance the Effect of Temozolomide on Glioblastoma Cells

INTRODUCTION

Glioblastoma (GB) is one of the deadliest human brain tumors. The prognosis is unfavorable, chemotherapy with temozolomide (TMZ) may extend the survival period for a patient. The paper aims to evaluate the survival rates among relapsing GB patients, who have been treated with valproic acid (VPA), and to study its effect on tumor cells when combined with TMZ and celecoxib (CXB).

MATERIALS AND METHODS

The research is based on retrospective analysis of the data from GB patients who had been treated with VPA as a part of a complex treatment protocol and reoperated due to a GB relapse. The experimental study involved cancer cells of C6, U87, and T98G lines. GB was modeled on Wistar rats. The research was approved by the ethics committee. Differences in groups were considered significant at p < 0.05 Results: The median of overall survival among GB patients who took VPA was 22 months, and for those who did not take VPA - 13 months. The in vitro experiment showed the half-maximal inhibitory concentration (IC50) of TMZ for various lines of cancer cells (CCs) varying from 435.3 to 844 μM. IC50 VPA for CCs of U87MG, T98G, and С6 lines was 1510, 3900, and 3600 μM: IC50 CXB for those lines of CCs was 30.1 μM, 41.07, and 48.4 μM respectively. VPA significantly enhanced the anti-glioma effect of TMZ on the U87 line of CCs, while CCs of C6 and T98G lines proved to be most susceptible to the combination of CXB and TMZ. The combination of VPA with CXB increased the anti-glioma effect of TMZ both in vitro and in vivo, also reducing the tumor size (р < 0.05) and prolonging the survival period among experimental animals.

CONCLUSION

VPA and CXB enhance the effect of TMZ on glioblastoma cells.

The Role and Applied Value of Mitochondria in Glioma-Related Research

Mitochondria, known as the "energy factory" of cells, are essential organelles with a double membrane structure and genetic material found in most eukaryotic cells. They play a crucial role in tumorigenesis and development, with alterations in mitochondrial structure and function in tumor cells leading to characteristics such as rapid proliferation, invasion, and drug resistance. Glioma, the most common brain tumor with a high recurrence rate and limited treatment options, has been linked to changes in mitochondrial structure and function. This review focuses on the bioenergetics, dynamics, metastasis, and autophagy of mitochondria in relation to glioma proliferation, as well as the potential use of mitochondria-targeting drugs in glioma treatment.

Metabolic dysregulation of tricarboxylic acid cycle and oxidative phosphorylation in glioblastoma

Glioblastoma multiforme (GBM) exhibits genetic alterations that induce the deregulation of oncogenic pathways, thus promoting metabolic adaptation. The modulation of metabolic enzyme activities is necessary to generate nucleotides, amino acids, and fatty acids, which provide energy and metabolic intermediates essential for fulfilling the biosynthetic needs of glioma cells. Moreover, the TCA cycle produces intermediates that play important roles in the metabolism of glucose, fatty acids, or non-essential amino acids, and act as signaling molecules associated with the activation of oncogenic pathways, transcriptional changes, and epigenetic modifications. In this review, we aim to explore how dysregulated metabolic enzymes from the TCA cycle and oxidative phosphorylation, along with their metabolites, modulate both catabolic and anabolic metabolic pathways, as well as pro-oncogenic signaling pathways, transcriptional changes, and epigenetic modifications in GBM cells, contributing to the formation, survival, growth, and invasion of glioma cells. Additionally, we discuss promising therapeutic strategies targeting key players in metabolic regulation. Therefore, understanding metabolic reprogramming is necessary to fully comprehend the biology of malignant gliomas and significantly improve patient survival.

Dual perspective on autophagy in glioma: Detangling the dichotomous mechanisms of signaling pathways for therapeutic insights

Autophagy is a normal physiological process that aids the recycling of cellular nutrients, assisting the cells to cope with stressed conditions. However, autophagy's effect on cancer, including glioma, is uncertain and involves complicated molecular mechanisms. Several contradictory reports indicate that autophagy may promote or suppress glioma growth and progression. Autophagy inhibitors potentiate the efficacy of chemotherapy or radiation therapy in glioma. Numerous compounds stimulate autophagy to cause glioma cell death. Autophagy is also involved in the therapeutic resistance of glioma. This review article aims to detangle the complicated molecular mechanism of autophagy to provide a better perception of the two-sided role of autophagy in glioma and its therapeutic implications. The protein and epigenetic modulators of the cytoprotective and cytotoxic role of autophagy are described in this article. Moreover, several signaling pathways are associated with autophagy and its effects on glioma. We have reviewed the molecular pathways and highlighted the signaling axis involved in cytoprotective and cytotoxic autophagy. Additionally, this article discusses the role of autophagy in therapeutic resistance, including glioma stem cell maintenance and tumor microenvironment regulation. It also summarizes several investigations on the anti-glioma effects of autophagy modulators to understand the associated mechanisms and provide insights regarding its therapeutic implications.

Regulation of cancer stem cells and immunotherapy of glioblastoma (Review)

Glioblastoma (GB) is one of the most adverse diagnoses in oncology. Complex current treatment results in a median survival of 15 months. Resistance to treatment is associated with the presence of cancer stem cells (CSCs). The present review aimed to analyze the mechanisms of CSC plasticity, showing the particular role of β-catenin in regulating vital functions of CSCs, and to describe the molecular mechanisms of Wnt-independent increase of β-catenin levels, which is influenced by the local microenvironment of CSCs. The present review also analyzed the reasons for the low effectiveness of using medication in the regulation of CSCs, and proposed the development of immunotherapy scenarios with tumor cell vaccines, containing heterogenous cancer cells able of producing a multidirectional antineoplastic immune response. Additionally, the possibility of managing lymphopenia by transplanting hematopoietic stem cells from a healthy sibling and using clofazimine or other repurposed drugs that reduce β-catenin concentration in CSCs was discussed in the present study.

Celecoxib Suppresses NF-κB p65 (RelA) and TNFα Expression Signaling in Glioblastoma

BACKGROUND

Glioblastoma (GBM) harbors significant genetic heterogeneity, high infiltrative capacity, and patterns of relapse following many therapies. The expression of nuclear factor kappa-B (NF-κB p65 (RelA)) and signaling pathways is constitutively activated in GBM through inflammatory stimulation such as tumor necrosis factor-alpha (TNFα), cell invasion, motility, abnormal physiological stimuli, and inducible chemoresistance. However, the underlying anti-tumor and anti-proliferative mechanisms of NF-κB p65 (RelA) and TNFα are still poorly defined. This study aimed to investigate the expression profiling of NF-κB p65 (RelA) and TNFα as well as the effectiveness of celecoxib along with temozolomide (TMZ) in reducing the growth of the human GBM cell line SF-767.

METHODS

genome-wide expression profiling, enrichment analysis, immune infiltration, quantitative expression, and the Microculture Tetrazolium Test (MTT) proliferation assay were performed to appraise the effects of celecoxib and TMZ.

RESULTS

demonstrated the upregulation of NF-κB p65 (RelA) and TNFα and celecoxib reduced the viability of the human glioblastoma cell line SF-767, cell proliferation, and NF-κB p65 (RelA) and TNFα expression in a dose-dependent manner. Overall, these findings demonstrate for the first time how celecoxib therapy could mitigate the invasive characteristics of the human GBM cell line SF-767 by inhibiting the NF-κB mediated stimulation of the inflammatory cascade.

CONCLUSION

based on current findings, we propose that celecoxib as a drug candidate in combination with temozolomide might dampen the transcriptional and enzymatic activities associated with the aggressiveness of GBM and reduce the expression of GBM-associated NF-κB p65 (RelA) and TNFα inflammatory genes expression.

Complementary roles of EP2 and EP4 receptors in malignant glioma

BACKGROUND AND PURPOSE

Glioblastoma (GBM) is the most aggressive brain tumour in the central nervous system, but the current treatment is very limited and unsatisfactory. PGE2 -initiated cAMP signalling via EP2 and EP4 receptors is involved in the tumourigenesis of multiple cancer types. However, whether or how EP2 and EP4 receptors contribute to GBM growth largely remains elusive.

EXPERIMENTAL APPROACH

We performed comprehensive data analysis of gene expression in human GBM samples and determined their expression correlations through multiple bioinformatics approaches. A time-resolved fluorescence energy transfer (TR-FRET) assay was utilized to characterize PGE2 -mediated cAMP signalling via EP2 and EP4 receptors in human glioblastoma cells. Using recently reported potent and selective small-molecule antagonists, we determined the effects of inhibition of EP2 and EP4 receptors on GBM growth in subcutaneous and intracranial tumour models.

KEY RESULTS

The expression of both EP2 and EP4 receptors was upregulated and highly correlated with a variety of tumour-promoting cytokines, chemokines, and growth factors in human gliomas. Further, they were heterogeneously expressed in human GBM cells, where they compensated for each other to mediate PGE2 -initiated cAMP signalling and to promote colony formation, cell invasion and migration. Inhibition of EP2 and EP4 receptors revealed that these receptors might mediate GBM growth, angiogenesis, and immune evasion in a compensatory manner.

CONCLUSION AND IMPLICATIONS

The compensatory roles of EP2 and EP4 receptors in GBM development and growth suggest that concurrently targeting these two PGE2 receptors might represent a more effective strategy than inhibiting either alone for GBM treatment.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

Multiple therapeutic approaches of glioblastoma multiforme: From terminal to therapy

Glioblastoma multiforme (GBM) is an aggressive brain cancer showing poor prognosis. Currently, treatment methods of GBM are limited with adverse outcomes and low survival rate. Thus, advancements in the treatment of GBM are of utmost importance, which can be achieved in recent decades. However, despite aggressive initial treatment, most patients develop recurrent diseases, and the overall survival rate of patients is impossible to achieve. Currently, researchers across the globe target signaling events along with tumor microenvironment (TME) through different drug molecules to inhibit the progression of GBM, but clinically they failed to demonstrate much success. Herein, we discuss the therapeutic targets and signaling cascades along with the role of the organoids model in GBM research. Moreover, we systematically review the traditional and emerging therapeutic strategies in GBM. In addition, we discuss the implications of nanotechnologies, AI, and combinatorial approach to enhance GBM therapeutics.

Drug Repurposing in Pediatric Brain Tumors: Posterior Fossa Ependymoma and Diffuse Midline Glioma under the Looking Glass

Tumors of the Central Nervous System (CNS) represent the leading cause of cancer-related deaths in children. Current treatment options are not curative for most malignant histologies, and intense preclinical and clinical research is needed to develop more effective therapeutic interventions against these tumors, most of which meet the FDA definition for orphan diseases. Increased attention is being paid to the repositioning of already-approved drugs for new anticancer indications as a fast-tracking strategy for identifying new and more effective therapies. Two pediatric CNS tumors, posterior fossa ependymoma (EPN-PF) type A and diffuse midline glioma (DMG) H3K27-altered, share loss of H3K27 trimethylation as a common epigenetic hallmark and display early onset and poor prognosis. These features suggest a potentially common druggable vulnerability. Successful treatment of these CNS tumors raises several challenges due to the location of tumors, chemoresistance, drug blood-brain barrier penetration, and the likelihood of adverse side effects. Recently, increasing evidence demonstrates intense interactions between tumor cell subpopulations and supportive tumor microenvironments (TMEs) including nerve, metabolic, and inflammatory TMEs. These findings suggest the use of drugs, and/or multi-drug combinations, that attack both tumor cells and the TME simultaneously. In this work, we present an overview of the existing evidence concerning the most preclinically validated noncancer drugs with antineoplastic activity. These drugs belong to four pharmacotherapeutic classes: antiparasitic, neuroactive, metabolic, and anti-inflammatory. Preclinical evidence and undergoing clinical trials in patients with brain tumors, with special emphasis on pediatric EPN-PF and DMG, are summarized and critically discussed.

Tumor Microenvironment in Gliomas: A Treatment Hurdle or an Opportunity to Grab?

Gliomas are the most frequent central nervous system (CNS) primary tumors. The prognosis and clinical outcomes of these malignancies strongly diverge according to their molecular alterations and range from a few months to decades. The tumor-associated microenvironment involves all cells and connective tissues surrounding tumor cells. The composition of the microenvironment as well as the interactions with associated neoplastic mass, are both variables assuming an increasing interest in these last years. This is mainly because the microenvironment can mediate progression, invasion, dedifferentiation, resistance to treatment, and relapse of primary gliomas. In particular, the tumor microenvironment strongly diverges from isocitrate dehydrogenase (IDH) mutated and wild-type (wt) tumors. Indeed, IDH mutated gliomas often show a lower infiltration of immune cells with reduced angiogenesis as compared to IDH wt gliomas. On the other hand, IDH wt tumors exhibit a strong immune infiltration mediated by several cytokines and chemokines, including CCL2, CCL7, GDNF, CSF-1, GM-CSF, etc. The presence of several factors, including Sox2, Oct4, PD-L1, FAS-L, and TGF β2, also mediate an immune switch toward a regulatory inhibited immune system. Other important interactions are described between IDH wt glioblastoma cells and astrocytes, neurons, and stem cells, while these interactions are less elucidated in IDH-mutated tumors. The possibility of targeting the microenvironment is an intriguing perspective in terms of therapeutic drug development. In this review, we summarized available evidence related to the glioma microenvironment, focusing on differences within different glioma subtypes and on possible therapeutic development.

Novel pyrazole-based COX-2 inhibitors as potential anticancer agents: Design, synthesis, cytotoxic effect against resistant cancer cells, cell cycle arrest, apoptosis induction and dual EGFR/Topo-1 inhibition

Novel differently substituted pyrazole derivatives were designed, synthesized and evaluated for their anticancer activity. All compounds selectively inhibited COX-2 enzyme (IC₅₀ = 0.043-0.56 μM). Compounds 11, 12 and 15 showed superior potency (IC₅₀ = 0.043-0.049 μM) and screened for their antiproliferative effect against MCF-7 and HT-29 cancer cell lines using doxorubicin and 5-FU as reference drugs. Compounds 11, 12 and 15 showed good potency against MCF-7 (IC₅₀ = 2.85-23.99 μM) and HT-29 (IC₅₀ = 2.12-69.37 μM) cell lines. Also, compounds 11, 12 and 15 displayed (IC₅₀ = 56.61-115.75 μM) against non-cancerous WI-38 cells compared to doxorubicin (IC₅₀ = 13.32 μM). Compound 11 showed superior cytotoxicity against both MCF-7 (IC₅₀ = 2.85) and HT-29 (IC₅₀ = 2.12 μM) and was more potent than 5-FU (HT-29: IC₅₀ = 8.77 μM). Besides, it displayed IC₅₀ of 115.75 μM against normal WI-38 cells regarding it as a safe cytotoxic agent. In addition, compound 11 displayed IC₅₀ values of 63.44 μM and 98.60 μM against resistant HT-29 and resistant MCF-7 cancer cell lines sequentially. The most potent compound arrested cell cycle at G1/S phase in HT-29 treated cells displaying accumulation of cells in G0 phase and increase in percentage of cells in both early and late apoptotic stages. Apoptotic induction ability was confirmed via up-regulation of BAX, down-regulation of Bcl-2 and activation of caspase-3/9 protein levels. Compound 11 inhibited both EGFR (IC₅₀ = 0.083 μM) and Topo-1 (IC₅₀ = 0.020 μM) enzymes. Also, compound 11 decreased both total and phosphorylated EGFR concentration in HT-29 cells. Finally, molecular docking study showed good binding interactions between novel compounds and target receptors.

Exploring the inverse association of glioblastoma multiforme and Alzheimer's disease via bioinformatics analysis

Glioblastoma multiforme (GBM) and Alzheimer's disease (AD) are two major diseases in the nervous system with a similar peak age of onset, which has the typical characteristics of high cost, difficult treatment, and poor prognosis. Epidemiological studies and a few molecular biological studies have hinted at an opposite relationship between AD and GBM. However, there are few studies on their reverse relationship, and the regulatory mechanism is still unclear, indicating that further systematic research is urgently needed. Our study firstly employs advanced bioinformatics methods to explore the inverse relationship between them and find various target drugs. We obtained the gene expression dataset from public databases (GEO, TCGA, and GTEx). Then, we identified 122 differentially expressed genes (DEGs) of AD and GBM. Four significant gene modules were identified through protein-protein interaction (PPI) and module construction, and 13 hub genes were found using cytoHubba. We constructed co-expression networks and found various target drugs through these hub genes. Functional enrichment analysis revealed that the AMPK pathway, cell cycle, and cellular senescence play important roles in AD and GBM. Our study may provide a potential direction for studying the opposite molecular mechanism of AD and GBM in the future.

Cyclooxygenase-2 Upregulated by Temozolomide in Glioblastoma Cells Is Shuttled In Extracellular Vesicles Modifying Recipient Cell Phenotype

Temozolomide (TMZ) resistance is frequent in patients with glioblastoma (GBM), a tumor characterized by a marked inflammatory microenvironment. Recently, we reported that cyclooxygenase-2 (COX-2) is upregulated in TMZ-resistant GBM cells treated with high TMZ concentrations. Moreover, COX-2 activity inhibition significantly counteracted TMZ-resistance of GBM cells. Extracellular vesicles (EV) are considered crucial mediators in orchestrating GBM drug resistance by modulating the tumor microenvironment (TME) and affecting the surrounding recipient cell phenotype and behavior. This work aimed to verify whether TMZ, at low and clinically relevant doses (5-20 µM), could induce COX-2 overexpression in GBM cells (T98G and U87MG) and explore if secreted EV shuttled COX-2 to recipient cells. The effect of COX-2 inhibitors (COXIB), Celecoxib (CXB), or NS398, alone or TMZ-combined, was also investigated. Our results indicated that TMZ at clinically relevant doses upregulated COX-2 in GBM cells. COXIB treatment significantly counteracted TMZ-induced COX-2 expression, confirming the crucial role of the COX-2/PGE2 system in TMZ-resistance. The COXIB specificity was verified on U251MG, COX-2 null GBM cells. Western blotting of GBM-EV cells showed the COX-2 presence, with the same intracellular trend, increasing in EV derived from TMZ-treated cells and decreasing in those derived from COXIB+TMZ-treated cells. We then evaluated the effect of EV secreted by TMZ-treated cells on U937 and U251MG, used as recipient cells. In human macrophage cell line U937, the internalization of EV derived by TMZ-T98G cells led to a shift versus a pro-tumor M2-like phenotype. On the other hand, EV from TMZ-T98G induced a significant decrease in TMZ sensitivity in U251MG cells. Overall, our results, in confirming the crucial role played by COX-2 in TMZ-resistance, provide the first evidence of the presence and effective functional transfer of this enzyme through EV derived from GBM cells, with multiple potential consequences at the level of TME.