Activation of Dopamine Receptor 2 Prompts Transcriptomic and Metabolic Plasticity in Glioblastoma

Domperidone Induces Apoptosis through Suppression of STAT3 Signaling in Human Renal Cancer Caki-2 Cells

Renal cancer continues to offer a great challenge for its successful therapy today, thus underscoring the need for effective chemotherapeutic agents. In the current study, we explored the anticancer effects of domperidone, a dopamine D2 receptor (DRD2) antagonist, in renal cancer Caki-2 cells. Domperidone induced dose and time-dependent cytotoxic effects in Caki-2 cells, triggering intrinsic apoptosis via the stimulation of the caspase cascade and PARP cleavage. The cytotoxic effect of domperidone was found to be partially DRD2-dependent. Domperidone treatment markedly augmented the production of intracellular reactive oxygen species which induced the cell death of Caki-2 cells. In addition, domperidone suppressed Janus kinase 2 and STAT3 phosphorylation, leading to inhibition of survival and proliferation of these cells. Hence, domperidone can be considered a promising candidate for renal cancer treatment.

Changes in adrenoceptor expression level contribute to the cellular plasticity of glioblastoma cells

Glioblastoma cells are known to regulate their cellular plasticity in response to their surrounding microenvironment, but it is not fully understood what factors contribute to the cells' changing plasticity. Here, we found that glioblastoma cells alter the expression level of adrenoreceptors depending on their differentiation stage. Catecholamines are abundant in the central nervous system, and we found that noradrenaline, in particular, enhances the stemness of glioblastoma cells and promotes the dedifferentiation potential of already differentiated glioblastoma cells. Antagonist and RNAi experiments revealed that signaling through α1D-adrenoreceptor is important for noradrenaline action on glioblastoma cells. We also found that high α1D-adrenoreceptor expression was associated with poor prognosis in patients with gliomas. These data suggest that glioblastoma cells increase the expression level of their own adrenoreceptors to alter the surrounding tumor microenvironment favorably for survival. We believe that our findings will contribute to the development of new therapeutic strategies for glioblastoma.

Amino acid metabolism in glioblastoma pathogenesis, immune evasion, and treatment resistance

Glioblastoma (GBM) ranks among the most lethal primary tumors of the central nervous system. This is partly due to its complex intracellular metabolism and interactions with the surrounding tumor microenvironment (TME). Compelling evidence represents that altered amino acids (AAs) metabolism plays a crucial role in both areas. The role of AAs and their metabolites in glioma biology is an emerging topic. Therefore, this review was conducted to summarize the current knowledge about the molecular mechanisms by which AAs participate in the GBM pathogenesis. AAs can directly influence tumor progression by affecting tumor cell metabolism or indirectly by releasing bioactive agents through particular metabolic pathways. This review begins by examining the metabolic pathways of essential AAs, such as tryptophan, tyrosine, and phenylalanine, which contribute to synthesizing critical neurotransmitters and shape tumor metabolism signatures. We explore how these pathways impact tumor growth and immune modulation, focusing on how AAs and their metabolites can promote malignant properties in GBM cells. AAs also play a pivotal role in reprogramming the TME, contributing to immune evasion and resistance to therapy. The review further discusses how tumor metabolism signatures, influenced by AA metabolism, can enhance the immunosuppressive microenvironment, providing new avenues for targeted immunotherapies. Finally, we outline potential therapeutic strategies to modulate AA metabolism and emphasize critical opportunities for future research to improve GBM management.

Synergistic combination of perphenazine and temozolomide suppresses patient-derived glioblastoma tumorspheres

BACKGROUND

Glioblastoma (GBM), a primary malignant brain tumor, has a poor prognosis, even with standard treatments such as radiotherapy and chemotherapy. In this study, we explored the anticancer effects of the synergistic combination of perphenazine (PER), a dopamine receptor D2/3 (DRD2/3) antagonist, and temozolomide (TMZ), a standard treatment for GBM, in patient-derived human GBM tumorspheres (TSs).

METHODS

The biological effects of the combination of PER and TMZ in GBM TSs were assessed by measuring cell viability, ATP, stemness, invasiveness, and apoptosis. Changes in protein and mRNA expression were analyzed using western blotting and RNA sequencing. Co-administration of PER and TMZ was evaluated in vivo using a mouse orthotopic xenograft model.

RESULTS

The Severance dataset showed that DRD2 and DRD3 expressions were higher in tumor tissues than in the tumor-free cortex of patients with GBM. DRD2/3 knockout by CRISPR/Cas9 in patient-derived human GBM TSs inhibited cell growth and ATP production. The combined treatment with PER and TMZ resulted in superior effects on cell viability and ATP assays compared to those in single treatment groups. Flow cytometry, western blotting, and RNA sequencing confirmed elevated apoptosis in GBM TSs following combination treatment. Additionally, the combination of PER and TMZ downregulated the expression of protein and mRNA associated with stemness and invasiveness. In vivo evaluation showed that combining PER and TMZ extended the survival period of the mouse orthotopic xenograft model.

CONCLUSIONS

The synergistic combination of PER and TMZ has potential as a novel combination treatment strategy for GBM.

Tumor-nerve interactions in cancer regulation and progression

Tumor-nerve interactions play a critical role in tumor progression, metastasis, and treatment resistance, redefining our understanding of the tumor microenvironment. This review provides a comprehensive analysis of how the peripheral and central nervous systems contribute to cancer biology, focusing on mechanisms of neural invasion, immune evasion, and tumor adaptation. It has highlighted the emerging potential of repurposing nervous system-targeted drugs originally developed for neurodegenerative and autoimmune diseases as innovative cancer therapies. The review also addresses key challenges, including the limitations of current experimental models and the complexity of translating preclinical findings to clinical applications. By bridging the gap between neuroscience and oncology, this interdisciplinary study aims to discover novel therapeutic strategies to improve outcomes for cancer patients.

Neurotransmitter-Mimicking Nanovesicles Facilitate Postoperative Glioblastoma Stem Cell-Specific Treatment for Preventing Tumor Recurrence

Survival quality of glioblastoma (GBM) patients remains undesirable despite the aggressive multimodal treatment methods implemented, which are strongly associated with tumor recurrence after surgical resection. Self-renewal and strong tumourigenic capacity of glioblastoma stem cells (GSCs) at the narrow margin of the incision are essential factors driving tumor secondary strikes. Currently, the challenges in treating postoperative residual GSCs are mainly due to the lack of materials for incision and GSCs targeting. In this study, a neurotransmitter-mimicking nanovesicle (PMVS-P) based on platelet membrane-derived vesicle (PMV) with anti-GSC drug salinomycin (SAL)-loading and polydopamine (PDA)-surface is synthesized. PMVS-P exhibits surgical incision targeting ability and specifically identified GSCs with highly expressed D2 dopamine receptor (D2DR), a central nervous system neurotransmitter receptor, thus suppressing GBM recurrence. This neurotransmitter-mimicking nanovesicle primed GSC-specific tumoricidal treatment with broadened applications for preventing tumor recurrence.

Novel strategies to overcome chemoresistance in human glioblastoma

Temozolomide (TMZ) is currently the first-line chemotherapeutic agent for the treatment of glioblastoma multiforme (GBM). However, the inherent heterogeneity of GBM often results in suboptimal outcomes, particularly due to varying degrees of resistance to TMZ. Over the past several decades, O6-methylguanine-DNA methyltransferase (MGMT)-mediated DNA repair pathway has been extensively investigated as a target to overcome TMZ resistance. Nonetheless, the combination of small molecule covalent MGMT inhibitors with TMZ and other chemotherapeutic agents has frequently led to adverse clinical effects. Recently, additional mechanisms contributing to TMZ resistance have been identified, including epidermal growth factor receptor (EGFR) mutations, overactivation of intracellular signalling pathways, energy metabolism reprogramming or survival autophagy, and changes in tumor microenvironment (TME). These findings suggest that novel therapeutic strategies targeting these mechanisms hold promise for overcoming TMZ resistance in GBM patients. In this review, we summarize the latest advancements in understanding the mechanisms underlying intrinsic and acquired TMZ resistance. Additionally, we compile various small-molecule compounds with potential to mitigate chemoresistance in GBM. These mechanism-based compounds may enhance the sensitivity of GBM to TMZ and related chemotherapeutic agents, thereby improving overall survival rates in clinical practice.

The Impact of Brain Tumors on Emotional and Behavioral Functioning

While the physical manifestations of brain tumors are well-documented, their impact on the emotional and psychological landscape of patients is of equal importance. Patients frequently experience a range of challenges from depression, apathy, and increased aggression to personality changes. The complexity of these changes and their effects on emotional functioning are shaped by tumor characteristics, including location, growth rate, and the corresponding hormonal imbalances. These challenges may ripple outward, affecting not only the patients themselves but also their caregivers. This review aims to examine the diverse emotional experiences associated with various brain tumor types and locations, through understanding the neurobiological mechanisms underlying these changes. The impact of psychosocial factors on emotional distress and coping strategies is also explored, focusing on the critical role of social support and resilience. The need for integrated care that addresses both the physical and psychological aspects of brain tumors is essential for improving the quality of life (QoL) for patients and their families. The close relationship between emotional and cognitive difficulties is analyzed, stressing how these challenges can mutually reinforce each other, creating a convoluted and challenging situation for brain tumor patients. By understanding and addressing these issues, healthcare providers can better support patients and improve their overall QoL. This review seeks to consolidate the current understanding of this complicated relationship, drawing from an array of studies, reviews, and meta-analyses.

High-throughput identification of repurposable neuroactive drugs with potent anti-glioblastoma activity

Glioblastoma, the most aggressive primary brain cancer, has a dismal prognosis, yet systemic treatment is limited to DNA-alkylating chemotherapies. New therapeutic strategies may emerge from exploring neurodevelopmental and neurophysiological vulnerabilities of glioblastoma. To this end, we systematically screened repurposable neuroactive drugs in glioblastoma patient surgery material using a clinically concordant and single-cell resolved platform. Profiling more than 2,500 ex vivo drug responses across 27 patients and 132 drugs identified class-diverse neuroactive drugs with potent anti-glioblastoma efficacy that were validated across model systems. Interpretable molecular machine learning of drug-target networks revealed neuroactive convergence on AP-1/BTG-driven glioblastoma suppression, enabling expanded in silico screening of more than 1 million compounds with high patient validation accuracy. Deep multimodal profiling confirmed Ca2+-driven AP-1/BTG-pathway induction as a neuro-oncological glioblastoma vulnerability, epitomized by the anti-depressant vortioxetine synergizing with current standard-of-care chemotherapies in vivo. These findings establish an actionable framework for glioblastoma treatment rooted in its neural etiology.

Navigating glioblastoma complexity: the interplay of neurotransmitters and chromatin

Glioblastoma is the most aggressive brain cancer with an unfavorable prognosis for patient survival. Glioma stem cells, a subpopulation of cancer cells, drive tumor initiation, self-renewal, and resistance to therapy and, together with the microenvironment, play a crucial role in glioblastoma maintenance and progression. Neurotransmitters such as noradrenaline, dopamine, and serotonin have contrasting effects on glioblastoma development, stimulating or inhibiting its progression depending on the cellular context and through their action on glioma stem cells, perhaps changing the epigenetic landscape. Recent studies have revealed that serotonin and dopamine induce chromatin modifications related to transcriptional plasticity in the mammalian brain and possibly in glioblastoma; however, this topic still needs to be explored because of its potential implications for glioblastoma treatment. Also, it is essential to consider that neurotransmitters' effects depend on the tumor's microenvironment since it can significantly influence the response and behavior of cancer cells. This review examines the possible role of neurotransmitters as regulators of glioblastoma development, focusing on their impact on the chromatin of glioma stem cells.

ARF4-mediated retrograde trafficking as a driver of chemoresistance in glioblastoma

BACKGROUND

Cellular functions hinge on the meticulous orchestration of protein transport, both spatially and temporally. Central to this process is retrograde trafficking, responsible for targeting proteins to the nucleus. Despite its link to many diseases, the implications of retrograde trafficking in glioblastoma (GBM) are still unclear.

METHODS

To identify genetic drivers of TMZ resistance, we conducted comprehensive CRISPR-knockout screening, revealing ADP-ribosylation factor 4 (ARF4), a regulator of retrograde trafficking, as a major contributor.

RESULTS

Suppressing ARF4 significantly enhanced TMZ sensitivity in GBM patient-derived xenograft (PDX) models, leading to improved survival rates (P < .01) in both primary and recurrent lines. We also observed that TMZ exposure stimulates ARF4-mediated retrograde trafficking. Proteomics analysis of GBM cells with varying levels of ARF4 unveiled the influence of this pathway on EGFR signaling, with increased nuclear trafficking of EGFR observed in cells with ARF4 overexpression and TMZ treatment. Additionally, spatially resolved RNA-sequencing of GBM patient tissues revealed substantial correlations between ARF4 and crucial nuclear EGFR (nEGFR) downstream targets, such as MYC, STAT1, and DNA-PK. Decreased activity of DNA-PK, a DNA repair protein downstream of nEGFR signaling that contributes to TMZ resistance, was observed in cells with suppressed ARF4 levels. Notably, treatment with DNA-PK inhibitor, KU-57788, in mice with a recurrent PDX line resulted in prolonged survival (P < .01), highlighting the promising therapeutic implications of targeting proteins reliant on ARF4-mediated retrograde trafficking.

CONCLUSIONS

Our findings demonstrate that ARF4-mediated retrograde trafficking contributes to the development of TMZ resistance, cementing this pathway as a viable strategy to overcome chemoresistance in GBM.

Exploring neuroadaptive cellular pathways in chronic morphine exposure: An in-vitro analysis of cabergoline and Mdivi-1 co-treatment effects on the autophagy-apoptosis axis

The complex impacts of prolonged morphine exposure continue to be a significant focus in the expanding area of addiction studies. This research investigates the effectiveness of a combined treatment using Cabergoline and Mdivi-1 to counteract the neuroadaptive changes caused by in vitro morphine treatment. The impact of Methadone, Cabergoline, and a combination of Cabergoline and Mdivi-1 on the cellular and molecular responses associated with Morphine-induced changes was studied in human Neuroblastoma (SK-N-MC) and Glioblastoma (U87-MG) cell lines that were exposed to prolong Morphine treatment. Cabergoline and Mdivi-1 combined treatment effectively influenced the molecular alterations associated with neuroadaptation in chronic morphine-exposed neural cells. This combination therapy normalized autophagy and reduced oxidative stress by enhancing total-antioxidant capacity, mitigating apoptosis, restoring BDNF expression, and balancing apoptotic elements. Our research outlines morphine's dual role in modulating mitochondrial dynamics via the dysregulation of the autophagy-apoptosis axis. This emphasizes the significant involvement of DRP1 activity in neurological adaptation processes, as well as disturbances in the dopaminergic pathway during in vitro chronic exposure to morphine in neural cells. This study proposes a novel approach by recommending the potential effectiveness of combining Cabergoline and Mdivi-1 to modulate the neuroadaptations caused by morphine. Additionally, we identified BDNF and PCNA in neural cells as potential neuroprotective markers for assessing the effectiveness of drugs against opioid toxicity, emphasizing the need for further validation. The study uncovers diverse effects observed in pretreated morphine glioblastoma cells under treatment with Cabergoline and methadone. This highlights the potential for new treatments in the DRD2 pathway and underscores the importance of investigating the interplay between autophagy and apoptosis to advance research in managing cancer-related pain. The study necessitates an in-depth investigation into the relationship between autophagy and apoptosis, with a specific emphasis on protein interactions and the dynamics of cell signaling.

Understanding the Significance of Hypoxia-Inducible Factors (HIFs) in Glioblastoma: A Systematic Review

BACKGROUND

The study aims to investigate the role of hypoxia-inducible factors (HIFs) in the development, progression, and therapeutic potential of glioblastomas.

METHODOLOGY

The study, following PRISMA guidelines, systematically examined hypoxia and HIFs in glioblastoma using MEDLINE (PubMed), Web of Science, and Scopus. A total of 104 relevant studies underwent data extraction.

RESULTS

Among the 104 studies, global contributions were diverse, with China leading at 23.1%. The most productive year was 2019, accounting for 11.5%. Hypoxia-inducible factor 1 alpha (HIF1α) was frequently studied, followed by hypoxia-inducible factor 2 alpha (HIF2α), osteopontin, and cavolin-1. Commonly associated factors and pathways include glucose transporter 1 (GLUT1) and glucose transporter 3 (GLUT3) receptors, vascular endothelial growth factor (VEGF), phosphoinositide 3-kinase (PI3K)-Akt-mechanistic target of rapamycin (mTOR) pathway, and reactive oxygen species (ROS). HIF expression correlates with various glioblastoma hallmarks, including progression, survival, neovascularization, glucose metabolism, migration, and invasion.

CONCLUSION

Overcoming challenges such as treatment resistance and the absence of biomarkers is critical for the effective integration of HIF-related therapies into the treatment of glioblastoma with the aim of optimizing patient outcomes.

Iloperidone and Temozolomide Synergistically Inhibit Growth, Migration and Enhance Apoptosis in Glioblastoma Cells

Glioblastoma (GBM) is a fatal astrocytic glioma with poor prognosis and treatment resistance. Repurposing potential FDA-approved drugs like anti-psychotics can address the concerns in a timely and cost-effective manner. Epidemiological studies have shown that patients with schizophrenic using anti-psychotics have a low incidence of GBM. Therefore, we aimed to investigate the therapeutic potential of atypical anti-psychotic Iloperidone (ILO) alone and in combination with Temozolomide (TMZ) against GBM. The study assessed the growth inhibitory effect of ILO, TMZ, and their combination (ILO + TMZ) on U-87MG and T-98G cell lines using an MTT assay. The drug interaction coefficient (CDI) was determined, and doses with synergistic effects were used for subsequent experiments, including migratory, invasion, and TUNEL assays. The expressions of DRD2, β-catenin, Dvl2, Twist, and Slug were assessed by RTq-PCR, whereas the β-catenin protein expression was also determined by immunocytochemistry. ILO (p < 0.05) and TMZ (p < 0.01) significantly inhibited the growth of U-87MG cells at all tested doses. The combination of 60 µM of both drugs showed synergistic activity with CDI < 1. The inhibition of migration and apoptosis was more pronounced in the case of combination treatment (p < 0.001). Inhibition of the invading cells was also found to be significant in ILO- and combination-treated groups (p < 0.001). ILO and combination treatment also significantly downregulated the expression of DRD2, while TMZ upregulated the expression (p < 0.001). The expressions of β-catenin (p < 0.001), Dvl2 (p < 0.001), Twist (p < 0.001), and Slug (p < 0.001) were also significantly downregulated in all treatment groups as compared to the vehicle control. The data suggest that ILO possesses strong growth inhibitory activity, possibly due to its effect on DRD2 and β-catenin expression and has the potential to be repurposed against GBM.

Glioma induces atypical depression-like behaviors in mice through the 5-HT and glutamatergic synapse pathways

Glioma patients often undertake psychiatric disorders such as depression and anxiety. There are several clinical epidemiological studies on glioma-associated depression, but basic research and corresponding animal experiments are still lacking. Here, we observed that glioma-bearing mice exhibited atypical depression-like behaviors in orthotopic glioma mouse models. The concentrations of monoamine neurotransmitters were detected by enzyme-linked immunosorbent assay (ELISA), revealing a decrease in 5-hydroxytryptamine (5-HT) levels in para-glioma tissues. The related gene expression levels also altered, detected by quantitative RT-PCR. Then, we developed a glioma-depression comorbidity mouse model. Through sucrose preference test (SPT), forced swimming test (FST), tail suspension test (TST) and other tests, we found that the occurrence of glioma could lead to changes in depression-like behaviors in a chronic unpredictable mild stress (CUMS) mouse model. The results of RNA sequencing (RNA-seq) indicated that the altered expression of glutamatergic synapse related genes in the paratumor tissues might be one of the main molecular features of the comorbidity model. Our findings suggested that the presence of glioma caused and altered depression-like behaviors, which was potentially related to the 5-HT and glutamatergic synapse pathways.

A longitudinal single-cell and spatial multiomic atlas of pediatric high-grade glioma

Pediatric high-grade glioma (pHGG) is an incurable central nervous system malignancy that is a leading cause of pediatric cancer death. While pHGG shares many similarities to adult glioma, it is increasingly recognized as a molecularly distinct, yet highly heterogeneous disease. In this study, we longitudinally profiled a molecularly diverse cohort of 16 pHGG patients before and after standard therapy through single-nucleus RNA and ATAC sequencing, whole-genome sequencing, and CODEX spatial proteomics to capture the evolution of the tumor microenvironment during progression following treatment. We found that the canonical neoplastic cell phenotypes of adult glioblastoma are insufficient to capture the range of tumor cell states in a pediatric cohort and observed differential tumor-myeloid interactions between malignant cell states. We identified key transcriptional regulators of pHGG cell states and did not observe the marked proneural to mesenchymal shift characteristic of adult glioblastoma. We showed that essential neuromodulators and the interferon response are upregulated post-therapy along with an increase in non-neoplastic oligodendrocytes. Through in vitro pharmacological perturbation, we demonstrated novel malignant cell-intrinsic targets. This multiomic atlas of longitudinal pHGG captures the key features of therapy response that support distinction from its adult counterpart and suggests therapeutic strategies which are targeted to pediatric gliomas.

Crosstalk between glioblastoma and tumor microenvironment drives proneural-mesenchymal transition through ligand-receptor interactions

Glioblastoma (GBM) is the most common intrinsic and aggressive primary brain tumor in adults, with a median survival of approximately 15 months. GBM heterogeneity is considered responsible for the treatment resistance and unfavorable prognosis. Proneural-mesenchymal transition (PMT) represents GBM malignant progression and recurrence, which might be a breakthrough to understand GBM heterogeneity and overcome treatment resistance. PMT is a complicated process influenced by crosstalk between GBM and tumor microenvironment, depending on intricate ligand-receptor interactions. In this review, we summarize the autocrine and paracrine pathways in the GBM microenvironment and related ligand-receptor interactions inducing PMT. We also discuss the current therapies targeting the PMT-related autocrine and paracrine pathways. Together, this review offers a comprehensive understanding of the failure of GBM-targeted therapy and ideas for future tendencies of GBM treatment.

Efficacy and safety of chlorpromazine as an adjuvant therapy for glioblastoma in patients with unmethylated MGMT gene promoter: RACTAC, a phase II multicenter trial

Introduction

Drug repurposing is a promising strategy to develop new treatments for glioblastoma. In this phase II clinical trial, we evaluated the addition of chlorpromazine to temozolomide in the adjuvant phase of the standard first-line therapeutic protocol in patients with unmethylated MGMT gene promoter.

Methods

This was a multicenter phase II single-arm clinical trial. The experimental procedure involved the combination of CPZ with standard treatment with TMZ in the adjuvant phase of the Stupp protocol in newly-diagnosed GBM patients carrying an unmethylated MGMT gene promoter. Progression-free survival was the primary endpoint. Secondary endpoints were overall survival and toxicity.

Results

Forty-one patients were evaluated. Twenty patients (48.7%) completed 6 cycles of treatment with TMZ+CPZ. At 6 months, 27 patients (65.8%) were without progression, achieving the primary endpoint. Median PFS was 8.0 months (95% CI: 7.0-9.0). Median OS was 15.0 months (95% CI: 13.1-16.9). Adverse events led to reduction or interruption of CPZ dosage in 4 patients (9.7%).

Discussion

The addition of CPZ to standard TMZ in the first-line treatment of GBM patients with unmethylated MGMT gene promoter was safe and led to a longer PFS than expected in this population of patients. These findings provide proof-of-concept for the potential of adding CPZ to standard TMZ treatment in GBM patients with unmethylated MGMT gene promoter.

Clinical trial registration

https://clinicaltrials.gov/study/NCT04224441, identifier NCT04224441.

Spatial transcriptomics in glioblastoma: is knowing the right zip code the key to the next therapeutic breakthrough?

Spatial transcriptomics, the technology of visualizing cellular gene expression landscape in a cells native tissue location, has emerged as a powerful tool that allows us to address scientific questions that were elusive just a few years ago. This technological advance is a decisive jump in the technological evolution that is revolutionizing studies of tissue structure and function in health and disease through the introduction of an entirely new dimension of data, spatial context. Perhaps the organ within the body that relies most on spatial organization is the brain. The central nervous system's complex microenvironmental and spatial architecture is tightly regulated during development, is maintained in health, and is detrimental when disturbed by pathologies. This inherent spatial complexity of the central nervous system makes it an exciting organ to study using spatial transcriptomics for pathologies primarily affecting the brain, of which Glioblastoma is one of the worst. Glioblastoma is a hyper-aggressive, incurable, neoplasm and has been hypothesized to not only integrate into the spatial architecture of the surrounding brain, but also possess an architecture of its own that might be actively remodeling the surrounding brain. In this review we will examine the current landscape of spatial transcriptomics in glioblastoma, outline novel findings emerging from the rising use of spatial transcriptomics, and discuss future directions and ultimate clinical/translational avenues.

Novel small molecules inhibit proteotoxicity and inflammation: Mechanistic and therapeutic implications for Alzheimer's Disease, healthspan and lifespan- Aging as a consequence of glycolysis

Inflammation drives many age-related, especially neurological, diseases, and likely mediates age-related proteotoxicity. For example, dementia due to Alzheimer's Disease (AD), cerebral vascular disease, many other neurodegenerative conditions is increasingly among the most devastating burdens on the American (and world) health system and threatens to bankrupt the American health system as the population ages unless effective treatments are developed. Dementia due to either AD or cerebral vascular disease, and plausibly many other neurodegenerative and even psychiatric conditions, is driven by increased age-related inflammation, which in turn appears to mediate Abeta and related proteotoxic processes. The functional significance of inflammation during aging is also supported by the fact that Humira, which is simply an antibody to the pro-inflammatory cytokine TNF-a, is the best-selling drug in the world by revenue. These observations led us to develop parallel high-throughput screens to discover small molecules which inhibit age-related Abeta proteotoxicity in a C. elegans model of AD AND LPS-induced microglial TNF-a. In the initial screen of 2560 compounds (Microsource Spectrum library) to delay Abeta proteotoxicity, the most protective compounds were, in order, phenylbutyrate, methicillin, and quetiapine, which belong to drug classes (HDAC inhibitors, beta lactam antibiotics, and tricyclic antipsychotics, respectably) already robustly implicated as promising to protect in neurodegenerative diseases, especially AD. RNAi and chemical screens indicated that the protective effects of HDAC inhibitors to reduce Abeta proteotoxicity are mediated by inhibition of HDAC2, also implicated in human AD, dependent on the HAT Creb binding protein (Cbp), which is also required for the protective effects of both dietary restriction and the daf-2 mutation (inactivation of IGF-1 signaling) during aging. In addition to methicillin, several other beta lactam antibiotics also delayed Abeta proteotoxicity and reduced microglial TNF-a. In addition to quetiapine, several other tricyclic antipsychotic drugs also delayed age-related Abeta proteotoxicity and increased microglial TNF-a, leading to the synthesis of a novel congener, GM310, which delays Abeta as well as Huntingtin proteotoxicity, inhibits LPS-induced mouse and human microglial and monocyte TNF-a, is highly concentrated in brain after oral delivery with no apparent toxicity, increases lifespan, and produces molecular responses highly similar to those produced by dietary restriction, including induction of Cbp inhibition of inhibitors of Cbp, and genes promoting a shift away from glycolysis and toward metabolism of alternate (e.g., lipid) substrates. GM310, as well as FDA-approved tricyclic congeners, prevented functional impairments and associated increase in TNF-a in a mouse model of stroke. Robust reduction of glycolysis by GM310 was functionally corroborated by flux analysis, and the glycolytic inhibitor 2-DG inhibited microglial TNF-a and other markers of inflammation, delayed Abeta proteotoxicity, and increased lifespan. These results support the value of phenotypic screens to discover drugs to treat age-related, especially neurological and even psychiatric diseases, including AD and stroke, and to clarify novel mechanisms driving neurodegeneration (e.g., increased microglial glycolysis drives neuroinflammation and subsequent neurotoxicity) suggesting novel treatments (selective inhibitors of microglial glycolysis).

The DRD2 Antagonist Haloperidol Mediates Autophagy-Induced Ferroptosis to Increase Temozolomide Sensitivity by Promoting Endoplasmic Reticulum Stress in Glioblastoma

PURPOSE

Temozolomide resistance remains a major obstacle in the treatment of glioblastoma (GBM). The combination of temozolomide with another agent could offer an improved treatment option if it could overcome chemoresistance and prevent side effects. Here, we determined the critical drug that cause ferroptosis in GBM cells and elucidated the possible mechanism by which drug combination overcomes chemoresistance.

EXPERIMENTAL DESIGN

Haloperidol/temozolomide synergism was assessed in GBM cell lines with different dopamine D2 receptor (DRD2) expression in vitro and in vivo. Inhibitors of ferroptosis, autophagy, endoplasmic reticulum (ER) stress and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) were used to validate the specific mechanisms by which haloperidol and temozolomide induce ferroptosis in GBM cells.

RESULTS

In the present work, we demonstrate that the DRD2 level is increased by temozolomide in a time-dependent manner and is inversely correlated with temozolomide sensitivity in GBM. The DRD2 antagonist haloperidol, a butylbenzene antipsychotic, markedly induces ferroptosis and effectively enhances temozolomide efficacy in vivo and in vitro. Mechanistically, haloperidol suppressed the effect of temozolomide on cAMP by antagonizing DRD2 receptor activity, and the increases in cAMP/PKA triggered ER stress, which led to autophagy and ferroptosis. Furthermore, elevated autophagy mediates downregulation of FTH1 expression at the posttranslational level in an autophagy-dependent manner and ultimately leads to ferroptosis.

CONCLUSIONS

Our results provide experimental evidence for repurposing haloperidol as an effective adjunct therapy to inhibit adaptive temozolomide resistance to enhance the efficacy of chemoradiotherapy in GBM, a strategy that may have broad prospects for clinical application.

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

Dopamine receptor D2 regulates glioblastoma survival and death through MET and death receptor 4/5

Recent studies indicate that signaling molecules traditionally associated with central nervous system function play critical roles in cancer. Dopamine receptor signaling is implicated in various cancers including glioblastoma (GBM) and it is a recognized therapeutic target, as evidenced by recent clinical trials with a selective dopamine receptor D2 (DRD2) inhibitor ONC201. Understanding the molecular mechanism(s) of the dopamine receptor signaling will be critical for development of potent therapeutic options. Using the human GBM patient-derived tumors treated with dopamine receptor agonists and antagonists, we identified the proteins that interact with DRD2. DRD2 signaling promotes glioblastoma (GBM) stem-like cells and GBM growth by activating MET. In contrast, pharmacological inhibition of DRD2 induces DRD2-TRAIL receptor interaction and subsequent cell death. Thus, our findings demonstrate a molecular circuitry of oncogenic DRD2 signaling in which MET and TRAIL receptors, critical factors for tumor cell survival and cell death, respectively, govern GBM survival and death. Finally, tumor-derived dopamine and expression of dopamine biosynthesis enzymes in a subset of GBM may guide patient stratification for DRD2 targeting therapy.

Swimming training and herbal nanoformulations as natural remedies to improve sensory-motor impairment in rat midbrain tumor models: system biology, behavioral test, and experimental validation

Motor impairment worsens health-related quality of life in patients with primary and metastatic midbrain tumors. Here, 56-male-Wistar rats were divided into eight groups: Normal group, Midbrain Tomur Model group, Model + Exe group, Model + Lipo, Model + Extract, Model + Lipo-Extract, Model + Extract-Exe, Model + Lipo-Extract + Exe. According to the aim, mid-brain tumor models were conducted by injections of the C6 glioma cell line (5 × 105 cell suspension) and stereotaxic techniques in the substantia nigra area. Furthermore, consumption of nanoformulation of herbals extract (100 mg/kg/day), crude extract (100 mg/kg/day), and swimming training (30 min, 3 days/week) as interventional protocols were performed for 6 weeks. In addition, we evaluated the effect of polyherbal nanoliposomes containing four plant extracts and swimming training on the GABArα1/TRKB/DRD2/DRD1a/TH network in the substantia nigra of the midbrain tumor rat model. Data emphasized that DRD2 might be a druggable protein with the network's highest significance cut-point effect that could modulate sensory-motor impairment. Furthermore, we found Quercetin, Ginsenosides, Curcumin, and Rutin, as bioactive compounds present in Ginseng, Matthiola incana, Turmeric, and Green-Tea extracts, could bind over the DRD2 protein with approved binding affinity scores. Based on our data, swimming training, and nanoliposome-enriched combined supplements could consider effective complementary medicine for motor impairment recovery induced by the midbrain tumor in the substantia nigra area. Hence, regular swimming training and natural medicines rich in polyphenolic bioactive components and antioxidative effects could modify and improve the dopamine receptors' function.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03574-3.

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.

Joint EANM/SIOPE/RAPNO practice guidelines/SNMMI procedure standards for imaging of paediatric gliomas using PET with radiolabelled amino acids and [18F]FDG: version 1.0

Positron emission tomography (PET) has been widely used in paediatric oncology. 2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is the most commonly used radiopharmaceutical for PET imaging. For oncological brain imaging, different amino acid PET radiopharmaceuticals have been introduced in the last years. The purpose of this document is to provide imaging specialists and clinicians guidelines for indication, acquisition, and interpretation of [18F]FDG and radiolabelled amino acid PET in paediatric patients affected by brain gliomas. There is no high level of evidence for all recommendations suggested in this paper. These recommendations represent instead the consensus opinion of experienced leaders in the field. Further studies are needed to reach evidence-based recommendations for the applications of [18F]FDG and radiolabelled amino acid PET in paediatric neuro-oncology. These recommendations are not intended to be a substitute for national and international legal or regulatory provisions and should be considered in the context of good practice in nuclear medicine. The present guidelines/standards were developed collaboratively by the EANM and SNMMI with the European Society for Paediatric Oncology (SIOPE) Brain Tumour Group and the Response Assessment in Paediatric Neuro-Oncology (RAPNO) working group. They summarize also the views of the Neuroimaging and Oncology and Theranostics Committees of the EANM and reflect recommendations for which the EANM and other societies cannot be held responsible.

Anticancer efficacy of endo- and exogenous potent ligands acting at dopaminergic receptor-expressing cancer cells

Cancer is one of the most common and dreaded diseases affecting the vastness of society. Unfortunately, still some people die especially when cancer is not diagnosed and thus caught early enough. On the other hand, using available chemo- or radiotherapy may result in serious side effects. Therefore, cancer-specific medications seem to be the most desired and safe therapy. Knowing that some cancers are characterized by overexpression of specific receptors on the cell surface, target-mediated drugs could serve as a unique and effective form of therapy. In line with this, recently dopaminergic receptors were presented important in cancer therapy as several dopaminergic ligands revealed their efficacy in tumor growth reduction as well as in apoptosis mediation. Unfortunately, the indication of whether DA receptor agonists or antagonists are the best choices in cancer treatment is quite difficult, since both of them may exert either pro- or anticancer effects. In this review, we analyze the therapeutic efficacy of compounds, both of exogenous and endogenous origin, targeting dopaminergic receptor-expressing cancers.

Treatment of cancer with antipsychotic medications: Pushing the boundaries of schizophrenia and cancer

Over a century ago, the phenothiazine dye, methylene blue, was discovered to have both antipsychotic and anti-cancer effects. In the 20th-century, the first phenothiazine antipsychotic, chlorpromazine, was found to inhibit cancer. During the years of elucidating the pharmacology of the phenothiazines, reserpine, an antipsychotic with a long historical background, was likewise discovered to have anti-cancer properties. Research on the effects of antipsychotics on cancer continued slowly until the 21st century when efforts to repurpose antipsychotics for cancer treatment accelerated. This review examines the history of these developments, and identifies which antipsychotics might treat cancer, and which cancers might be treated by antipsychotics. The review also describes the molecular mechanisms through which antipsychotics may inhibit cancer. Although the overlap of molecular pathways between schizophrenia and cancer have been known or suspected for many years, no comprehensive review of the subject has appeared in the psychiatric literature to assess the significance of these similarities. This review fills that gap and discusses what, if any, significance the similarities have regarding the etiology of schizophrenia.

Iron commensalism of mesenchymal glioblastoma promotes ferroptosis susceptibility upon dopamine treatment

The heterogeneity of glioblastoma multiforme (GBM) leads to poor patient prognosis. Here, we aim to investigate the mechanism through which GBM heterogeneity is coordinated to promote tumor progression. We find that proneural (PN)-GBM stem cells (GSCs) secreted dopamine (DA) and transferrin (TF), inducing the proliferation of mesenchymal (MES)-GSCs and enhancing their susceptibility toward ferroptosis. PN-GSC-derived TF stimulates MES-GSC proliferation in an iron-dependent manner. DA acts in an autocrine on PN-GSC growth in a DA receptor D1-dependent manner, while in a paracrine it induces TF receptor 1 expression in MES-GSCs to assist iron uptake and thus enhance ferroptotic vulnerability. Analysis of public datasets reveals worse prognosis of patients with heterogeneous GBM with high iron uptake than those with other GBM subtypes. Collectively, the findings here provide evidence of commensalism symbiosis that causes MES-GSCs to become iron-addicted, which in turn provides a rationale for targeting ferroptosis to treat resistant MES GBM.

Glioblastoma stem-cell derived mesenchymal cells become reliant on iron but vulnerable to ferroptosis and within patients of heterogeneous glioblastoma multiforme prognosis for those with high iron uptake is poorer than other subtypes.

Prognostic Neurotransmitter Receptors Genes Are Associated with Immune Response, Inflammation and Cancer Hallmarks in Brain Tumors

Glioblastoma multiforme (GBM) is one of the most aggressive forms of cancer. Neurotransmitters (NTs) have recently been linked with the uncontrolled proliferation of cancer cells, but the role of NTs in the progression of human gliomas is still largely unexplored. Here, we investigate the genes encoding for neurotransmitter receptors (NTRs) by analyzing public transcriptomic data from GBM and LGG (low-grade glioma) samples. Our results showed that 50 out of the 98 tested NTR genes were dysregulated in brain cancer tissue. Next, we identified and validated NTR-associated prognostic gene signatures for both LGG and GBM. A subset of 10 NTR genes (DRD1, HTR1E, HTR3B, GABRA1, GABRA4, GABRB2, GABRG2, GRIN1, GRM7, and ADRA1B) predicted a positive prognosis in LGG and a negative prognosis in GBM. These genes were progressively downregulated across glioma grades and exhibited a strong negative correlation with genes associated with immune response, inflammasomes, and established cancer hallmarks genes in lower grade gliomas, suggesting a putative role in inhibiting cancer progression. This study might have implications for the development of novel therapeutics and preventive strategies that target regulatory networks associated with the link between the autonomic nervous system, cancer cells, and the tumor microenvironment.

Perphenazine and prochlorperazine decrease glioblastoma U‑87 MG cell migration and invasion: Analysis of the ABCB1 and ABCG2 transporters, E‑cadherin, α‑tubulin and integrins (α3, α5, and β1) levels

Glioblastoma multiforme is the most frequent type of malignant brain tumor, and is one of the most lethal and untreatable human tumors with a very poor survival rate. Therefore, novel and effective strategies of treatment are required. Integrins play a crucial role in the regulation of cellular adhesion and invasion. Integrins and α-tubulin are very important in cell migration, whereas E-cadherin plays a main role in tumor metastasis. Notably, drugs serve a crucial role in glioblastoma treatment; however, they have to penetrate the blood-brain barrier (BBB) to be effective. ABC transporters, including ATP binding cassette subfamily B member 1 (ABCB1) and ATP binding cassette subfamily G member 2 (ABCG2), are localized in the brain endothelial capillaries of the BBB, have a crucial role in the development of multidrug resistance and are modulated by phenothiazine derivatives. The impact of perphenazine and prochlorperazine on the motility of human Uppsala 87 malignant glioma (U87-MG) cells was evaluated using a wound-healing assay, cellular migration and invasion were assessed by Transwell assay, and the protein expression levels of ABCB1, ABCG2, E-cadherin, α-tubulin and integrins were determined by western blotting. The present study explored the effects of perphenazine and prochlorperazine on the levels of ABCB1, ABCG2, E-cadherin, α-tubulin and integrins (α3, α5, and β1), as well as on the migratory and invasive ability of U87-MG cells. The results suggested that perphenazine and prochlorperazine may modulate the expression levels of multidrug resistance proteins (they decreased ABCB1 and increased ABCG2 expression), E-cadherin, α-tubulin and integrins, and could impair the migration and invasion of U-87 MG cells. In conclusion, the decrease in migratory and invasive ability following treatment with phenothiazine derivatives due to the increase in ABCG2 and E-cadherin expression, and decrease in α-tubulin and integrins expression, may suggest that research on perphenazine and prochlorperazine in the treatment of glioblastoma is worth continuing.

Review: Neurological Complications From Therapies for Pediatric Brain Tumors

Surgery, chemotherapy and radiation have been the mainstay of pediatric brain tumor treatment over the past decades. Recently, new treatment modalities have emerged for the management of pediatric brain tumors. These therapies range from novel radiotherapy techniques and targeted immunotherapies to checkpoint inhibitors and T cell transfer therapies. These treatments are currently investigated with the goal of improving survival and decreasing morbidity. However, compared to traditional therapies, these novel modalities are not as well elucidated and similarly has the potential to cause significant short and long-term sequelae, impacting quality of life. Treatment complications are commonly mediated through direct drug toxicity or vascular, infectious, or autoimmune mechanisms, ranging from immune effector cell associated neurotoxicity syndrome with CART-cells to neuropathy with checkpoint inhibitors. Addressing treatment-induced complications is the focus of new trials, specifically improving neurocognitive outcomes. The aim of this review is to explore the pathophysiology underlying treatment related neurologic side effects, highlight associated complications, and describe the future direction of brain tumor protocols. Increasing awareness of these neurologic complications from novel therapies underscores the need for quality-of-life metrics and considerations in clinical trials to decrease associated treatment-induced morbidity.

Neural Signaling in Cancer

Nervous system activity regulates development, homeostasis, and plasticity of the brain as well as other organs in the body. These mechanisms are subverted in cancer to propel malignant growth. In turn, cancers modulate neural structure and function to augment growth-promoting neural signaling in the tumor microenvironment. Approaching cancer biology from a neuroscience perspective will elucidate new therapeutic strategies for presently lethal forms of cancer. In this review, we highlight the neural signaling mechanisms recapitulated in primary brain tumors, brain metastases, and solid tumors throughout the body that regulate cancer progression. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Tackling the Behavior of Cancer Cells: Molecular Bases for Repurposing Antipsychotic Drugs in the Treatment of Glioblastoma

Glioblastoma (GBM) is associated with a very dismal prognosis, and current therapeutic options still retain an overall unsatisfactorily efficacy in clinical practice. Therefore, novel therapeutic approaches and effective medications are highly needed. Since the development of new drugs is an extremely long, complex and expensive process, researchers and clinicians are increasingly considering drug repositioning/repurposing as a valid alternative to the standard research process. Drug repurposing is also under active investigation in GBM therapy, since a wide range of noncancer and cancer therapeutics have been proposed or investigated in clinical trials. Among these, a remarkable role is played by the antipsychotic drugs, thanks to some still partially unexplored, interesting features of these agents. Indeed, antipsychotic drugs have been described to interfere at variable incisiveness with most hallmarks of cancer. In this review, we analyze the effects of antipsychotics in oncology and how these drugs can interfere with the hallmarks of cancer in GBM. Overall, according to available evidence, mostly at the preclinical level, it is possible to speculate that repurposing of antipsychotics in GBM therapy might contribute to providing potentially effective and inexpensive therapies for patients with this disease.

Repurposing Antipsychotics for Cancer Treatment

Cancer is a leading cause of death worldwide, with approximately 19 million new cases each year. Lately, several novel chemotherapeutic drugs have been introduced, efficiently inhibiting tumor growth and proliferation. However, developing a new drug is a time- and money-consuming process, requiring around 1 billion dollars and nearly ten years, with only a minority of the initially effective anti-cancer drugs experimentally finally being efficient in human clinical trials. Drug repurposing for cancer treatment is an optimal alternative as the safety of these drugs has been previously tested, and thus, in case of successful preclinical studies, can be introduced faster and with a lower cost into phase 3 clinical trials. Antipsychotic drugs are associated with anti-cancer properties and, lately, there has been an increasing interest in their role in cancer treatment. In the present review, we discussed in detail the in-vitro and in-vivo properties of the most common typical and atypical antipsychotics, along with their mechanism of action.

Pharmacological Characterization of the Imipridone Anticancer Drug ONC201 Reveals a Negative Allosteric Mechanism of Action at the D2 Dopamine Receptor

ONC201 is a first-in-class imipridone compound that is in clinical trials for the treatment of high-grade gliomas and other advanced cancers. Recent studies identified that ONC201 antagonizes D2-like dopamine receptors at therapeutically relevant concentrations. In the current study, characterization of ONC201 using radioligand binding and multiple functional assays revealed that it was a full antagonist of the D2 and D3 receptors (D2R and D3R) with low micromolar potencies, similar to its potency for antiproliferative effects. Curve-shift experiments using D2R-mediated β-arrestin recruitment and cAMP assays revealed that ONC201 exhibited a mixed form of antagonism. An operational model of allostery was used to analyze these data, which suggested that the predominant modulatory effect of ONC201 was on dopamine efficacy with little to no effect on dopamine affinity. To investigate how ONC201 binds to the D2R, we employed scanning mutagenesis coupled with a D2R-mediated calcium efflux assay. Eight residues were identified as being important for ONC201's functional antagonism of the D2R. Mutation of these residues followed by assessing ONC201 antagonism in multiple signaling assays highlighted specific residues involved in ONC201 binding. Together with computational modeling and simulation studies, our results suggest that ONC201 interacts with the D2R in a bitopic manner where the imipridone core of the molecule protrudes into the orthosteric binding site, but does not compete with dopamine, whereas a secondary phenyl ring engages an allosteric binding pocket that may be associated with negative modulation of receptor activity. SIGNIFICANCE STATEMENT: ONC201 is a novel antagonist of the D2 dopamine receptor with demonstrated efficacy in the treatment of various cancers, especially high-grade glioma. This study demonstrates that ONC201 antagonizes the D2 receptor with novel bitopic and negative allosteric mechanisms of action, which may explain its high selectivity and some of its clinical anticancer properties that are distinct from other D2 receptor antagonists widely used for the treatment of schizophrenia and other neuropsychiatric disorders.

X-Linked Tumor Suppressor Genes Act as Presumed Contributors in the Sex Chromosome-Autosome Crosstalk in Cancers

Since the human genome contains about 6% of tumor suppressor genes (TSGs) and the X chromosome alone holds a substantial share (2%), herein, we have discussed exclusively the relative contribution of X-linked human TSGs that appear to be primarily involved in 32 different cancer types. Our analysis showed that, (a) the majority of X-linked TSGs are primarily involved in the dysregulation of breast cancer, followed by prostate cancer, (b) Despite being escaped from X chromosome inactivation (XCI), a clear pattern of altered promoter methylation linked to the mutational burden was observed among them. (c) X-linked TSGs (mainly on the q-arm) maintain spatial and genetic interactions with certain autosomal loci. Corroborating our previous findings that loss/gain of entire sex chromosomes (in XO and XXY syndromes) can profoundly affect the epigenetic status of autosomes we herein suggest that X-linked TSGs alone can also contribute significantly in the dynamics this sex chromosome-autosome crosstalk to restructure the cancer genome.

Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy

G-protein-coupled receptors (GPCRs) are increasingly being considered as possible therapeutic targets in cancers. Activation of GPCR on tumors can have prominent growth effects, and GPCRs are frequently over-/ectopically expressed on tumors and thus can be used for targeted therapy. CNS/neural tumors are receiving increasing attention using this approach. Gliomas are the most frequent primary malignant brain/CNS tumor with glioblastoma having a 10-year survival <1%; neuroblastomas are the most common extracranial solid tumor in children with long-term survival<40%, and medulloblastomas are less common, but one subgroup has a 5-year survival <60%. Thus, there is an increased need for more effective treatments of these tumors. The Bombesin-receptor family (BnRs) is one of the GPCRs that are most frequently over/ectopically expressed by common tumors and is receiving particular attention as a possible therapeutic target in several tumors, particularly in prostate, breast, and lung cancer. We review in this paper evidence suggesting why a similar approach in some CNS/neural tumors (gliomas, neuroblastomas, medulloblastomas) should also be considered.

Electrotherapies for Glioblastoma

Non-thermal, intermediate frequency (100-500 kHz) electrotherapies present a unique therapeutic strategy to treat malignant neoplasms. Here, pulsed electric fields (PEFs) which induce reversible or irreversible electroporation (IRE) and tumour-treating fields (TTFs) are reviewed highlighting the foundations, advances, and considerations of each method when applied to glioblastoma (GBM). Several biological aspects of GBM that contribute to treatment complexity (heterogeneity, recurrence, resistance, and blood-brain barrier(BBB)) and electrophysiological traits which are suggested to promote glioma progression are described. Particularly, the biological responses at the cellular and molecular level to specific parameters of the electrical stimuli are discussed offering ways to compare these parameters despite the lack of a universally adopted physical description. Reviewing the literature, a disconnect is found between electrotherapy techniques and how they target the biological complexities of GBM that make treatment difficult in the first place. An attempt is made to bridge the interdisciplinary gap by mapping biological characteristics to different methods of electrotherapy, suggesting important future research topics and directions in both understanding and treating GBM. To the authors' knowledge, this is the first paper that attempts an in-tandem assessment of the biological effects of different aspects of intermediate frequency electrotherapy methods, thus offering possible strategies toward GBM treatment.

Paliperidone Inhibits Glioblastoma Growth in Mouse Brain Tumor Model and Reduces PD-L1 Expression

Simple Summary

The present study showed that a prescribed psychotropic medicine paliperidone inhibits GBM growth and prolongs survival in mouse brain tumor model and decreased the programmed death ligand 1 expression. Using the 3D co-culture also found that dopamine receptor D2 regulates the interaction of GBM-macrophage-induced PD-L1 expression in GBMs. In addition, the expression of DRD2 and PD-L1 in GBM modulates tumor-associated macrophage polarization. Our results also indicated that there is a contact-independent mechanism of PD-L1 induction in GBM upon interaction between GBM and monocytes. The present study also found that the interaction of GBM-macrophage-enhanced PD-L1 expression in GBM occurred by modulating the ERK and STAT3 signaling pathways. In addition, the inhibition of DRD2 reduces the upregulation of PD-1 expression, and it is regulating signaling in GBM.

Abstract

A previous study from our group reported that monocyte adhesion to glioblastoma (GBM) promoted tumor growth and invasion activity and increased tumor-associated macrophages (TAMs) proliferation and inflammatory mediator secretion as well. The present study showed that prescribed psychotropic medicine paliperidone reduced GBM growth and immune checkpoint protein programmed death ligand (PD-L)1 expression and increased survival in an intracranial xenograft mouse model. An analysis of the database of patients with glioma showed that the levels of PD-L1 and dopamine receptor D (DRD)2 were higher in the GBM group than in the low grade astrocytoma and non-tumor groups. In addition, GFP expressing GBM (GBM-GFP) cells co-cultured with monocytes-differentiated macrophage enhanced PD-L1 expression in GBM cells. The enhancement of PD-L1 in GBM was antagonized by paliperidone and risperidone as well as DRD2 selective inhibitor L741426. The expression of CD206 (M2 phenotype marker) was observed to be markedly increased in bone marrow-derived macrophages (BMDMs) co-cultured with GBM. Importantly, treatment with paliperidone effectively decreased CD206 and also dramatically increased CD80 (M1 phenotype marker) in BMDMs. We have previously established a PD-L1 GBM-GFP cell line that stably expresses PD-L1. Experiments showed that the expressions of CD206 was increased and CD80 was mildly decreased in the BMDMs co-cultured with PD-L1 GBM-GFP cells. On the other hands, knockdown of DRD2 expression in GBM cells dramatically decreased the expression of CD206 but markedly increased CD80 expressions in BMDMs. The present study suggests that DRD2 may be involved in regulating the PD-L1 expression in GBM and the microenvironment of GBM. Our results provide a valuable therapeutic strategy and indicate that treatments combining DRD2 antagonist paliperidone with standard immunotherapy may be beneficial for GBM treatment.

Effects of the DRD2/3 antagonist ONC201 and radiation in glioblastoma

BACKGROUND

Glioblastoma (GBM) is the deadliest of all brain cancers in adults. The current standard-of-care is surgery followed by radiotherapy and temozolomide, leading to a median survival time of only 15 months. GBM are organized hierarchically with a small number of glioma-initiating cells (GICs), responsible for therapy resistance and tumor recurrence, suggesting that targeting GICs could improve treatment response. ONC201 is a first-in-class anti-tumor agent with clinical efficacy in some forms of high-grade gliomas. Here we test its efficacy against GBM in combination with radiation.

METHODS

Using patient-derived GBM lines and mouse models of GBM we test the effects of radiation and ONC201 on GBM self-renewalin vitro and survivalin vivo.A possible resistance mechanism is investigated using RNA-Sequencing.

RESULTS

Treatment of GBM cells with ONC201 reduced self-renewal, clonogenicity and cell viabilityin vitro. ONC201 exhibited anti-tumor effects on radioresistant GBM cells indicated by reduced self-renewal in secondary and tertiary glioma spheres. Combined treatment of ONC201 and radiation prolonged survival in syngeneic and patient-derived orthotopic xenograft mouse models of GBM. Subsequent transcriptome analyses after combined treatment revealed shifts in gene expression signatures related to quiescent GBM populations, GBM plasticity, and GBM stem cells.

CONCLUSIONS

Our findings suggest that combined treatment with the DRD2/3 antagonist ONC201 and radiation improves the efficacy of radiation against GBMin vitroandin vivothrough suppression of GICs without increasing toxicity in mouse models of GBM. A clinical assessment of this novel combination therapy against GBM is further warranted.

Novel dopamine receptor 3 antagonists inhibit the growth of primary and temozolomide resistant glioblastoma cells

Treatment for the lethal primary adult brain tumor glioblastoma (GBM) includes the chemotherapy temozolomide (TMZ), but TMZ resistance is common and correlates with promoter methylation of the DNA repair enzyme O-6-methylguanine-DNA methyltransferase (MGMT). To improve treatment of GBMs, including those resistant to TMZ, we explored the potential of targeting dopamine receptor signaling. We found that dopamine receptor 3 (DRD3) is expressed in GBM and is also a previously unexplored target for therapy. We identified novel antagonists of DRD3 that decreased the growth of GBM xenograft-derived neurosphere cultures with minimal toxicity against human astrocytes and/or induced pluripotent stem cell-derived neurons. Among a set of DRD3 antagonists, we identified two compounds, SRI-21979 and SRI-30052, that were brain penetrant and displayed a favorable therapeutic window analysis of The Cancer Genome Atlas data demonstrated that higher levels of DRD3 (but not DRD2 or DRD4) were associated with worse prognosis in primary, MGMT unmethylated tumors. These data suggested that DRD3 antagonists may remain efficacious in TMZ-resistant GBMs. Indeed, SRI-21979, but not haloperidol, significantly reduced the growth of TMZ-resistant GBM cells. Together our data suggest that DRD3 antagonist-based therapies may provide a novel therapeutic option for the treatment of GBM.

Rediscovering potential molecular targets for glioma therapy through the analysis of the cell of origin, microenvironment, and metabolism

Gliomas are the most common type of malignant brain tumors. Despite significant medical advances, gliomas remain incurable and are associated with high mortality. Although numerous biomarkers of diagnostic value have been identified and significant progress in the prognosis of the outcome has been made, the treatment has not been parallelly improved during the last three decades. This review summarizes and discusses three aspects of recent discoveries related to glioma, with the objective to highlight the advantages of glioma-specific drugs targeting the cell of origin, microenvironment, and metabolism. Given the heterogeneous nature of gliomas, various cell populations have been implicated as likely sources of the tumor. Depending on the mutation(s) acquired by the cells, it is believed that neuronal stem/progenitor cells, oligodendrocyte progenitor cells, mature neurons, and glial cells can initiate cell transformation into a malignant phenotype. The level of tumorigenicity appears to be inversely correlated with the maturation of a given cell population. The microenvironment of gliomas includes non-cancer cells such as immune cells, fibroblasts, and cells of blood vessels, as well as secreted molecules and the extracellular matrix, and all these components play a vital role during tumor initiation and progression. We will discuss in detail how the tumor microenvironment can stimulate and drive the transformation of non-tumor cell populations into tumor-supporting cells or glioma cells. Metabolic reprogramming is a key feature of gliomas and is thought to reflect the adaptation to the increased nutritional requirements of tumor cell proliferation, growth, and survival. Mutations in the IDH gene can shape metabolic reprogramming and may generate some vulnerabilities in glioma cells, such as abnormal lipid metabolism and sensitivity to endoplasmic reticulum stress (ERS). We will analyze the prominent metabolic features of malignant gliomas and the key pathways regulating glioma metabolism. This review is intended to provide a conceptual background for the development of glioma therapies based on the properties of tumor cell populations, microenvironment, and metabolism.

Epidermal growth factor receptor as a molecular determinant of glioblastoma response to dopamine receptor D2 inhibitors

BACKGROUND

There are ongoing clinical trials exploring the efficacy of dopamine receptor D2 (DRD2) inhibition against glioblastomas, the most common primary brain tumor. Here we examine potential molecular determinants of this efficacy.

METHODS

The Cancer Genome Atlas glioblastoma database and other published mRNA profiles were used to analyze the DRD2 and epidermal growth factor receptor (EGFR) expression pattern. In vitro and in vivo responses to DRD2 inhibitors were determined using patient-derived xenograft (PDX) glioblastoma models. Immunohistochemical studies were performed on clinically annotated glioblastoma samples derived from patients treated with ONC201.

RESULTS

Analysis of clinical glioblastoma specimens derived from independent patient cohorts revealed an inverse correlation between EGFR and DRD2 mRNA expression, with implication that signaling mediated by these proteins shares overlapping functions. In independent panels of PDX glioblastoma lines, high EGFR expression was associated with poor in vitro and in vivo response to DRD2 inhibitors, including haloperidol and ONC201. Moreover, ectopic expression of a constitutively active EGFR, variant (v)III, suppressed glioblastoma sensitivity to ONC201. DRD2 expression positively correlated with expression of rate-limiting enzymes for dopamine synthesis as well as dopamine secretion, suggesting contribution of autocrine DRD2 signaling. Analysis of specimens from patients treated with ONC201 (n = 15) showed an inverse correlation between the intensity of EGFR staining and clinical response. The median overall survival for patients with high and low EGFR staining was 162 and 373 days, respectively (0.037).

CONCLUSIONS

High EGFR expression is a determinant of poor glioblastoma response to DRD2. This finding should inform future clinical trial designs.

De novo purine biosynthesis is a major driver of chemoresistance in glioblastoma

Glioblastoma is a primary brain cancer with a near 100% recurrence rate. Upon recurrence, the tumour is resistant to all conventional therapies, and because of this, 5-year survival is dismal. One of the major drivers of this high recurrence rate is the ability of glioblastoma cells to adapt to complex changes within the tumour microenvironment. To elucidate this adaptation's molecular mechanisms, specifically during temozolomide chemotherapy, we used chromatin immunoprecipitation followed by sequencing and gene expression analysis. We identified a molecular circuit in which the expression of ciliary protein ADP-ribosylation factor-like protein 13B (ARL13B) is epigenetically regulated to promote adaptation to chemotherapy. Immuno-precipitation combined with liquid chromatography-mass spectrometry binding partner analysis revealed that that ARL13B interacts with the purine biosynthetic enzyme inosine-5'-monophosphate dehydrogenase 2 (IMPDH2). Further, radioisotope tracing revealed that this interaction functions as a negative regulator for purine salvaging. Inhibition of the ARL13B-IMPDH2 interaction enhances temozolomide-induced DNA damage by forcing glioblastoma cells to rely on the purine salvage pathway. Targeting the ARLI3B-IMPDH2 circuit can be achieved using the Food and Drug Administration-approved drug, mycophenolate mofetil, which can block IMPDH2 activity and enhance the therapeutic efficacy of temozolomide. Our results suggest and support clinical evaluation of MMF in combination with temozolomide treatment in glioma patients.

Involvement of the Catecholamine Pathway in Glioblastoma Development

Glioblastoma (GBM) is the most aggressive tumor of the central nervous system (CNS). The standard of care improves the overall survival of patients only by a few months. Explorations of new therapeutic targets related to molecular properties of the tumor are under way. Even though neurotransmitters and their receptors normally function as mediators of interneuronal communication, growing data suggest that these molecules are also involved in modulating the development and growth of GBM by acting on neuronal and glioblastoma stem cells. In our previous DNA CpG methylation studies, gene ontology analyses revealed the involvement of the monoamine pathway in sequential GBM. In this follow-up study, we quantitated the expression levels of four selected catecholamine pathway markers (alpha 1D adrenergic receptor-ADRA1D; adrenergic beta receptor kinase 1 or G protein-coupled receptor kinase 2-ADRBK1/GRK2; dopamine receptor D2-DRD2; and synaptic vesicle monoamine transporter-SLC18A2) by immunohistochemistry, and compared the histological scores with the methylation levels within the promoters + genes of these markers in 21 pairs of sequential GBM and in controls. Subsequently, we also determined the promoter and gene methylation levels of the same markers in an independent database cohort of sequential GBM pairs. These analyses revealed partial inverse correlations between the catecholamine protein expression and promoter + gene methylation levels, when the tumor and control samples were compared. However, we found no differences in the promoter + gene methylation levels of these markers in either our own or in the database primary-recurrent GBM pairs, despite the higher protein expression of all markers in the primary samples. This observation suggests that regulation of catecholamine expression is only partially related to CpG methylation within the promoter + gene regions, and additional mechanisms may also influence the expression of these markers in progressive GBM. These analyses underscore the involvement of certain catecholamine pathway markers in GBM development and suggest that these molecules mediating or modulating tumor growth merit further exploration.

Anticancer Properties of the Antipsychotic Drug Chlorpromazine and Its Synergism With Temozolomide in Restraining Human Glioblastoma Proliferation In Vitro

The extremely poor prognosis of patients affected by glioblastoma (GBM, grade IV glioma) prompts the search for new and more effective therapies. In this regard, drug repurposing or repositioning can represent a safe, swift, and inexpensive way to bring novel pharmacological approaches from bench to bedside. Chlorpromazine, a medication used since six decades for the therapy of psychiatric disorders, shows in vitro several features that make it eligible for repositioning in cancer therapy. Using six GBM cell lines, three of which growing as patient-derived neurospheres and displaying stem-like properties, we found that chlorpromazine was able to inhibit viability in an apoptosis-independent way, induce hyperdiploidy, reduce cloning efficiency as well as neurosphere formation and downregulate the expression of stemness genes in all these cell lines. Notably, chlorpromazine synergized with temozolomide, the first-line therapeutic in GBM patients, in hindering GBM cell viability, and both drugs strongly cooperated in reducing cloning efficiency and inducing cell death in vitro for all the GBM cell lines assayed. These results prompted us to start a Phase II clinical trial on GBM patients (EudraCT # 2019-001988-75; ClinicalTrials.gov Identifier: NCT04224441) by adding chlorpromazine to temozolomide in the adjuvant phase of the standard first-line therapeutic protocol.

Biological activity of weekly ONC201 in adult recurrent glioblastoma patients

BACKGROUND

ONC201 is a dopamine receptor D2 (DRD2) antagonist that penetrates the blood-brain barrier. ONC201 efficacy has been shown in glioblastoma animal models and is inversely correlated with dopamine receptor DRD5 expression. ONC201 is well tolerated in adult recurrent glioblastoma patients with dosing every 3 weeks and has achieved an objective radiographic response in a patient harboring the H3 K27M mutation.

METHODS

In a window-of-opportunity arm, 6 adult subjects initiated ONC201 prior to re-resection of recurrent glioblastoma with intratumoral concentrations as the primary endpoint. An additional 20 adults with recurrent glioblastoma received single agent weekly oral ONC201 at 625 mg, with progression-free survival at 6 months (PFS6) by Response Assessment in Neuro-Oncology (RANO) criteria as the primary endpoint.

RESULTS

The window-of-opportunity arm achieved its primary endpoint with intratumoral ONC201 concentrations at ~24 hours following the second weekly dose ranging from 600 nM to 9.3 µM. Intratumoral pharmacodynamics assessed by activating transcriptional factor 4, death receptor 5, and apoptosis induction relative to archival samples were observed with the strongest intensity and uniformity among patients with low DRD5 tumor expression. The primary endpoint of PFS6 by RANO was not achieved at 5% in this molecularly unselected cohort; however, 1 of 3 patients enrolled with the H3 K27M mutation had a complete regression of enhancing multifocal lesions that remained durable for >1.5 years. No treatment modifications or discontinuations due to toxicity were observed, including in those who underwent re-resection.

CONCLUSIONS

Weekly ONC201 is well tolerated, and meaningful intratumoral concentrations were achieved. ONC201 may be biologically active in a subset of adult patients with recurrent glioblastoma.

Dopamine Receptor Antagonists, Radiation, and Cholesterol Biosynthesis in Mouse Models of Glioblastoma

BACKGROUND

Glioblastoma is the deadliest brain tumor in adults, and the standard of care consists of surgery followed by radiation and treatment with temozolomide. Overall survival times for patients suffering from glioblastoma are unacceptably low indicating an unmet need for novel treatment options.

METHODS

Using patient-derived HK-157, HK-308, HK-374, and HK-382 glioblastoma lines, the GL261 orthotopic mouse models of glioblastoma, and HK-374 patient-derived orthotopic xenografts, we tested the effect of radiation and the dopamine receptor antagonist quetiapine on glioblastoma self-renewal in vitro and survival in vivo. A possible resistance mechanism was investigated using RNA-sequencing. The blood-brain-barrier-penetrating statin atorvastatin was used to overcome this resistance mechanism. All statistical tests were 2-sided.

RESULTS

Treatment of glioma cells with the dopamine receptor antagonist quetiapine reduced glioma cell self-renewal in vitro, and combined treatment of mice with quetiapine and radiation prolonged the survival of glioma-bearing mice. The combined treatment induced the expression of genes involved in cholesterol biosynthesis. This rendered GL261 and HK-374 orthotopic tumors vulnerable to simultaneous treatment with atorvastatin and further statistically significantly prolonged the survival of C57BL/6 (n = 10 to 16 mice per group; median survival not reached; log-rank test, P < .001) and NOD Scid gamma mice (n = 8 to 21 mice per group; hazard ratio = 3.96, 95% confidence interval = 0.29 to 12.40; log-rank test, P < .001), respectively.

CONCLUSIONS

Our results indicate promising therapeutic efficacy with the triple combination of quetiapine, atorvastatin, and radiation treatment against glioblastoma without increasing the toxicity of radiation. With both drugs readily available for clinical use, our study could be rapidly translated into a clinical trial.