Fluvoxamine, an anti-depressant, inhibits human glioblastoma invasion by disrupting actin polymerization

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.

Pharmacological treatment of depression in patients with brain tumors

Patients with brain tumors suffer from intense psychosocial distress. Although the prevalence of depressive symptoms in patients with brain tumors is high, the pharmacological antidepressant treatment of those patients is not well defined and results from clinical trials are largely missing. In this review, we describe the current standard of evidence and clinical guidelines for the pharmacological treatment of depression in brain tumor patients. We present specific side effects and interactions that should guide treatment decisions. Furthermore, we provide evidence for the diagnosis, screening and risk factors for depression in brain tumor patients and we elaborate on potential antineoplastic effects of antidepressant drugs and ongoing clinical trials. Antidepressant drugs should not be withheld from patients with brain tumors. Future clinical trials should explore the effectiveness and side effects of antidepressants in this specific patient population.

Antidepressant Sertraline Hydrochloride Inhibits the Growth of HER2+ AU565 Breast Cancer Cell Line through Induction of Apoptosis and Cell Cycle Arrest

BACKGROUND

Drug repurposing in oncology promises benefits to many patients through its ability to provide novel, and fast-tracked treatments. Previous studies have demonstrated that depression may influence tumor progression. Anti-proliferative activity of certain antidepressants, mainly selective serotonin reuptake inhibitors (SSRIs), are reported in the literature.

OBJECTIVE

This study was conducted to repurpose selective serotonin reuptake inhibitors (SSRIs) for the treatment of breast cancers, and it merits further validation and research.

METHODS

Changes in cell morphology were studied using DAPI staining, while the Annexin V/PI method was employed for apoptotic analysis. The expression of specific genes involved in cancer progression was also analyzed via RT-PCR. Caspase-3 activation was measured through fluorometric assay.

RESULTS

We have identified that sertraline hydrochloride significantly inhibited the growth of breast cancer cell in vitro. Preliminary mechanistic studies demonstrated that the cytotoxicity of sertraline hydrochloride was possibly through the induction of apoptosis, as inferred from enhanced nuclear fragmentation, flow cytometric data, and caspase-3/7 activation. Gene expression analysis also showed an increased expression of pro-apoptotic Bax, and a slight decrease in oncogene c-myc in the presence of sertraline hydrochloride.

CONCLUSION

In conclusion, our study suggest that sertraline hydrochloride, an antidepressant drug, can potentially be used for the treatment of breast cancer.

Sigma-1 Receptor Agonist Fluvoxamine Ameliorates Fibrotic Response of Trabecular Meshwork Cells

Primary open-angle glaucoma remains a global issue, lacking a definitive treatment. Increased intraocular pressure (IOP) is considered the primary risk factor of the disease and it can be caused by fibrotic-like changes in the trabecular meshwork (TM) such as increased tissue stiffness and outflow resistance. Previously, we demonstrated that the sigma-1 receptor (S1R) agonist fluvoxamine (FLU) has anti-fibrotic properties in the kidney and lung. In this study, the localization of the S1R in TM cells was determined, and the anti-fibrotic efficacy of FLU was examined in both mouse and human TM cells. Treatment with FLU reduced the F-actin rearrangement, inhibited cell proliferation and migration induced by the platelet-derived growth factor and decreased the levels of fibrotic proteins. The protective role of the S1R in fibrosis was confirmed by a more pronounced increase in alpha smooth muscle actin and F-actin bundle and clump formation in primary mouse S1R knockout TM cells. Furthermore, FLU demonstrated its protective effects by increasing the production of nitric oxide and facilitating the degradation of the extracellular matrix through the elevation of cathepsin K. These findings suggest that the S1R could be a novel target for the development of anti-fibrotic drugs and offer a new therapeutic approach for glaucoma.

Association of antidepressant drug use with outcome of patients with glioblastoma

Depressive symptoms are common among patients with glioblastoma, but patients are often not treated with antidepressants. There is only limited evidence on the association of antidepressant drug use with survival in glioblastoma. We performed a pooled analysis of patients treated within the CENTRIC, CORE, AVAglio and ACT-IV trials to explore the relation of antidepressant drug use with progression-free (PFS) and overall survival (OS) at baseline, at the start of maintenance therapy and at the start of maintenance cycle 4. We further assessed the association of antidepressant drugs with seizure, cognition, fatigue and a diagnosis of depression. Among more than 1700 patients, we found no significant association between the use of antidepressants at baseline or at the start of maintenance therapy and PFS or OS. However, we found OS, but not PFS, to be significantly worse in patients using antidepressants at the start of maintenance cycle 4. After adjustment for antiepileptic drug use and despite showing a trend for increased risk, seizures were not significantly associated with antidepressant drug use, nor was there a change in mini mental state examination (MMSE) scores or fatigue by antidepressant drug use at baseline. However, there was a significant positive association between antidepressant use at the start of maintenance treatment and fatigue during maintenance treatment. The association of antidepressant use at the start of maintenance cycle 4 with inferior OS of glioblastoma patients requires independent confirmation and further study. Further prospective trials should evaluate efficacy, side effects and associations with outcome of antidepressants in glioblastoma.

The dark side of mRNA translation and the translation machinery in glioblastoma

Among the different types of cancer affecting the central nervous system (CNS), glioblastoma (GB) is classified by the World Health Organization (WHO) as the most common and aggressive CNS cancer in adults. GB incidence is more frequent among persons aged 45–55 years old. GB treatments are based on tumor resection, radiation, and chemotherapies. The current development of novel molecular biomarkers (MB) has led to a more accurate prediction of GB progression. Moreover, clinical, epidemiological, and experimental studies have established genetic variants consistently associated with the risk of suffering GB. However, despite the advances in these fields, the survival expectancy of GB patients is still shorter than 2 years. Thus, fundamental processes inducing tumor onset and progression remain to be elucidated. In recent years, mRNA translation has been in the spotlight, as its dysregulation is emerging as a key cause of GB. In particular, the initiation phase of translation is most involved in this process. Among the crucial events, the machinery performing this phase undergoes a reconfiguration under the hypoxic conditions in the tumor microenvironment. In addition, ribosomal proteins (RPs) have been reported to play translation-independent roles in GB development. This review focuses on the research elucidating the tight relationship between translation initiation, the translation machinery, and GB. We also summarize the state-of-the-art drugs targeting the translation machinery to improve patients’ survival. Overall, the recent advances in this field are shedding new light on the dark side of translation in GB.

Fluvoxamine prompts the antitumor immune effect via inhibiting the PD-L1 expression on mice-burdened colon tumor

A colon tumor, one of the digestive tract malignant tumors, is harmful to human health. A potential new treatment still deserves attention. The development of a new drug needs more resources, including time and expense. Therefore, the old drug with new targets has become a current research hotspot. Fluvoxamine, as an antidepressant, could play an effect on inhibiting 5-hydroxytryptamine reuptake. In the present research, the antitumor effects and possible mechanisms of fluvoxamine are validated. The results showed that fluvoxamine significantly suppressed the migration and proliferation of tumor cells, and increased the apoptosis in vitro. Additionally, fluvoxamine significantly delays tumor development, and prompts the apoptosis in tumor tissues of mice-burdened colon tumors in vivo. The tumor suppression might be related with that fluvoxamine inhibits the expression of phosphorylated signal transducer and activator of transcription 3, matrix metalloproteinase 2, and cleaved-caspase 3. Importantly, fluvoxamine significantly reduces the expression level of programmed cell death ligand 1. This could be a possible reason that treatment with fluvoxamine drives the infiltration of T lymphocytes and M1-type macrophages in tumor tissues. Taken together, this research suggests that fluvoxamine might be a promising drug to treat colon cancer by inhibiting the proliferation and migration, inducing apoptosis, and even increasing the immune response of antitumor.

In vitro anti-cancer effects of beauvericin through inhibition of actin polymerization and Src phosphorylation

BACKGROUND

Beauvericin (BEA) is a depsipeptide with antimicrobial, anti-inflammatory, and anti-cancer activities isolated from Beauveria bassiana. However, little is understood on its anti-cancer activities and mechanism.

PURPOSE

Aim of this study was to explore the anti-cancer activity of BEA and its underlying molecular mechanism to provide a theoretical basis for its role as a candidate natural drug in cancer diseases.

STUDY DESIGN

Various cancer cells such as C6 glioma, U251, MDA-MB-231, HeLa, HCT-15, LoVo cells, and HEK293T cells were used to the anti-cancer activity of BEA.

METHODS

To evaluate the anti-cancer activity of BEA, cell viability test (MTT assay), morphological change check, confocal microscopy, actin polymerization assay, flow cytometry, and Western blotting analysis. To check the target enzyme of BEA, overexpression and site-directed mutagenesis was employed.

RESULTS

BEA inhibited the viability of cancer cells including C6, MDA-MB-231, HeLa, HCT-15, LoVo, and U251 cells. Treatment of BEA in C6 glioma cells induced cell membrane blebbing and apoptosis. Caspase-3 and -9 were dose-dependently activated by BEA, and the mRNA expression of Bcl-2 was inhibited by BEA. According to confocal microscopy, actin polymerization and actin-actin interaction were interrupted by BEA in C6 cells. BEA regulated the apoptosis of C6 cells depending on the protein phosphorylation of Src and Signal transducer and activator of transcription (STAT3). Moreover, c-terminal amino acids in Src directly interacted with BEA in C6 cells, and the binding of Src and BEA suppressed the kinase activity of Src.

CONCLUSIONS

These results suggest that BEA may be a critical candidate or substitute drug for cancer treatment via suppression of the Src/STAT3 pathway.

Advances in co-opting anti-depressant drugs in glioma therapy

A study by Chryplewicz et al. demonstrated the efficacy of combining tricyclic antidepressant imipramine and anti-VEGF therapy in treating genetically engineered glioma models. Dual therapy synergistically improved vascular integrity, increased autophagy, and modulated the myeloid and lymphoid compartments in glioma.

Protocadherin 15 suppresses oligodendrocyte progenitor cell proliferation and promotes motility through distinct signalling pathways

Oligodendrocyte progenitor cells (OPCs) express protocadherin 15 (Pcdh15), a member of the cadherin superfamily of transmembrane proteins. Little is known about the function of Pcdh15 in the central nervous system (CNS), however, Pcdh15 expression can predict glioma aggression and promote the separation of embryonic human OPCs immediately following a cell division. Herein, we show that Pcdh15 knockdown significantly increases extracellular signal-related kinase (ERK) phosphorylation and activation to enhance OPC proliferation in vitro. Furthermore, Pcdh15 knockdown elevates Cdc42-Arp2/3 signalling and impairs actin kinetics, reducing the frequency of lamellipodial extrusion and slowing filopodial withdrawal. Pcdh15 knockdown also reduces the number of processes supported by each OPC and new process generation. Our data indicate that Pcdh15 is a critical regulator of OPC proliferation and process motility, behaviours that characterise the function of these cells in the healthy CNS, and provide mechanistic insight into the role that Pcdh15 might play in glioma progression.

Protocadherin 15 promotes lamellipodial and filopodial dynamics in oligodendrocyte progenitor cells by regulating Cdc42-Arp2/3 activity, but also suppresses ERK1/2 phosphorylation to reduce proliferation.

Modernistic and Emerging Developments of Nanotechnology in Glioblastoma-Targeted Theranostic Applications

Brain tumors such as glioblastoma are typically associated with an unstoppable cell proliferation with aggressive infiltration behavior and a shortened life span. Though treatment options such as chemotherapy and radiotherapy are available in combating glioblastoma, satisfactory therapeutics are still not available due to the high impermeability of the blood–brain barrier. To address these concerns, recently, multifarious theranostics based on nanotechnology have been developed, which can deal with diagnosis and therapy together. The multifunctional nanomaterials find a strategic path against glioblastoma by adjoining novel thermal and magnetic therapy approaches. Their convenient combination of specific features such as real-time tracking, in-depth tissue penetration, drug-loading capacity, and contrasting performance is of great demand in the clinical investigation of glioblastoma. The potential benefits of nanomaterials including specificity, surface tunability, biodegradability, non-toxicity, ligand functionalization, and near-infrared (NIR) and photoacoustic (PA) imaging are sufficient in developing effective theranostics. This review discusses the recent developments in nanotechnology toward the diagnosis, drug delivery, and therapy regarding glioblastoma.

Wnt and PI3K/Akt/mTOR Survival Pathways as Therapeutic Targets in Glioblastoma

Glioblastoma (GBM) is a devastating type of brain tumor, and current therapeutic treatments, including surgery, chemotherapy, and radiation, are palliative at best. The design of effective and targeted chemotherapeutic strategies for the treatment of GBM require a thorough analysis of specific signaling pathways to identify those serving as drivers of GBM progression and invasion. The Wnt/β-catenin and PI3K/Akt/mTOR (PAM) signaling pathways are key regulators of important biological functions that include cell proliferation, epithelial–mesenchymal transition (EMT), metabolism, and angiogenesis. Targeting specific regulatory components of the Wnt/β-catenin and PAM pathways has the potential to disrupt critical brain tumor cell functions to achieve critical advancements in alternative GBM treatment strategies to enhance the survival rate of GBM patients. In this review, we emphasize the importance of the Wnt/β-catenin and PAM pathways for GBM invasion into brain tissue and explore their potential as therapeutic targets.

Drug repositioning: Using psychotropic drugs for the treatment of glioma

Psychotropic drugs can penetrate the blood-brain barrier and regulate the levels of neurotransmitters and neuromodulators such as γ-aminobutyric acid, glutamate, serotonin, dopamine, and norepinephrine in the brain, and thus influence neuronal activity. Neuronal activity in the tumor microenvironment can promote the growth and expansion of glioma. There is increasing evidence that in addition to their use in the treatment of mental disorders, antipsychotic, antidepressant, and mood-stabilizing drugs have clinical potential for cancer therapy. These drugs have been shown to inhibit the malignant progression of glioma by targeting signaling pathways related to cell proliferation, apoptosis, or invasion/migration or by increasing the sensitivity of glioma cells to conventional chemotherapy or radiotherapy. In this review, we summarize findings from preclinical and clinical studies investigating the use of antipsychotics, antidepressants, and mood stabilizers in the treatment of various types of cancer, with a focus on glioma; and discuss their presumed antitumor mechanisms. The existing evidence indicates that psychotropic drugs with established pharmacologic and safety profiles can be repurposed as anticancer agents, thus providing new options for the treatment of glioma.

Drug Repurposing for Glioblastoma and Current Advances in Drug Delivery-A Comprehensive Review of the Literature

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults with an extremely poor prognosis. There is a dire need to develop effective therapeutics to overcome the intrinsic and acquired resistance of GBM to current therapies. The process of developing novel anti-neoplastic drugs from bench to bedside can incur significant time and cost implications. Drug repurposing may help overcome that obstacle. A wide range of drugs that are already approved for clinical use for the treatment of other diseases have been found to target GBM-associated signaling pathways and are being repurposed for the treatment of GBM. While many of these drugs are undergoing pre-clinical testing, others are in the clinical trial phase. Since GBM stem cells (GSCs) have been found to be a main source of tumor recurrence after surgery, recent studies have also investigated whether repurposed drugs that target these pathways can be used to counteract tumor recurrence. While several repurposed drugs have shown significant efficacy against GBM cell lines, the blood–brain barrier (BBB) can limit the ability of many of these drugs to reach intratumoral therapeutic concentrations. Localized intracranial delivery may help to achieve therapeutic drug concentration at the site of tumor resection while simultaneously minimizing toxicity and side effects. These strategies can be considered while repurposing drugs for GBM.

Repurposing of Anticancer Stem Cell Drugs in Brain Tumors

Brain tumors in adults may be infrequent when compared with other cancer etiologies, but they remain one of the deadliest with bleak survival rates. Current treatment modalities encompass surgical resection, chemotherapy, and radiotherapy. However, increasing resistance rates are being witnessed, and this has been attributed, in part, to cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells that reside within the tumor bulk and have the capacity for self-renewal and can differentiate and proliferate into multiple cell lineages. Studying those CSCs enables an increasing understanding of carcinogenesis, and targeting CSCs may overcome existing treatment resistance. One approach to weaponize new drugs is to target these CSCs through drug repurposing which entails using drugs, which are Food and Drug Administration-approved and safe for one defined disease, for a new indication. This approach serves to save both time and money that would otherwise be spent in designing a totally new therapy. In this review, we will illustrate drug repurposing strategies that have been used in brain tumors and then further elaborate on how these approaches, specifically those that target the resident CSCs, can help take the field of drug repurposing to a new level.

Repurposing antidepressants for anticancer drug discovery

Drug repurposing is an attractive strategy for identifying new indications for existing drugs. Three approved antidepressants have advanced into clinical trials for cancer therapy. In particular, further medicinal chemistry efforts with tranylcypromine (TCP) have led to the discovery of several TCP-based histone lysine specific demethylase 1 (LSD1) inhibitors that display therapeutic promise for treating cancer in the clinic. Thus repurposing antidepressants could be a promising strategy for cancer treatment. In this review, we illustrate the anticancer mechanisms of action of antidepressants and also discuss the challenges and future directions of repurposing antidepressants for anticancer drug discovery, to provide an overview of approved antidepressant cancer therapies.

Intuitive repositioning of an anti-depressant drug in combination with tivozanib: precision medicine for breast cancer therapy

Despite the existing therapies and lack of receptors such as HER-2, estrogen receptor and progesterone receptor, triple-negative breast cancer is one of the most aggressive subtypes of breast cancer. TNBCs are known for their highly aggressive metastatic behavior and typically migrate to brain and bone for secondary site propagation. Many diseases share similar molecular pathology exposing new avenues in molecular signaling for engendering innovative therapies. Generation of newer therapies and novel drugs are time consuming associated with very high resources. In order to provide personalized or precision medicine, drug repositioning will contribute in a cost-effective manner. In our study, we have repurposed and used a neoteric combination of two drug molecules namely, fluvoxamine and tivozanib, to target triple-negative breast cancer growth and progression. Our combination regime significantly targets two diverse but significant pathways in TNBCs. Subsequent analysis on migratory, invasive, and angiogenic properties showed the significance of our repurposed drug combination. Molecular array data resulted in identifying the specific and key players participating in cancer progression when the drug combination was used. The innovative combination of fluvoxamine and tivozanib reiterates the use of drug repositioning for precision medicine and subsequent companion diagnostic development.

An Alternative Pipeline for Glioblastoma Therapeutics: A Systematic Review of Drug Repurposing in Glioblastoma

Simple Summary

Glioblastoma is a devastating malignancy that has continued to prove resistant to a variety of therapeutics. No new systemic therapy has been approved for use against glioblastoma in almost two decades. This observation is particularly disturbing given the amount of money invested in identifying novel therapies for this disease. A relatively rapid and economical pipeline for identification of novel agents is drug repurposing. Here, a comprehensive review detailing the state of drug repurposing in glioblastoma is provided. We reveal details on studies that have examined agents in vitro, in animal models and in patients. While most agents have not progressed beyond the initial stages, several drugs, from a variety of classes, have demonstrated promising results in early phase clinical trials.

Abstract

The treatment of glioblastoma (GBM) remains a significant challenge, with outcome for most pa-tients remaining poor. Although novel therapies have been developed, several obstacles restrict the incentive of drug developers to continue these efforts including the exorbitant cost, high failure rate and relatively small patient population. Repositioning drugs that have well-characterized mechanistic and safety profiles is an attractive alternative for drug development in GBM. In ad-dition, the relative ease with which repurposed agents can be transitioned to the clinic further supports their potential for examination in patients. Here, a systematic analysis of the literature and clinical trials provides a comprehensive review of primary articles and unpublished trials that use repurposed drugs for the treatment of GBM. The findings demonstrate that numerous drug classes that have a range of initial indications have efficacy against preclinical GBM models and that certain agents have shown significant potential for clinical benefit. With examination in randomized, placebo-controlled trials and the targeting of particular GBM subgroups, it is pos-sible that repurposing can be a cost-effective approach to identify agents for use in multimodal anti-GBM strategies.

Erianthridin suppresses non-small-cell lung cancer cell metastasis through inhibition of Akt/mTOR/p70S6K signaling pathway

Cancer metastasis is a major cause of the high mortality rate in lung cancer patients. The cytoskeletal rearrangement and degradation of extracellular matrix are required to facilitate cell migration and invasion and the suppression of these behaviors is an intriguing approach to minimize cancer metastasis. Even though Erianthridin (ETD), a phenolic compound isolated from the Thai orchid Dendrobium formosum exhibits various biological activities, the molecular mechanism of ETD for anti-cancer activity is unclear. In this study, we found that noncytotoxic concentrations of ETD (≤ 50 μM) were able to significantly inhibit cell migration and invasion via disruption of actin stress fibers and lamellipodia formation. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 was markedly downregulated in a dose-dependent manner after ETD treatment. Mechanistic studies revealed that protein kinase B (Akt) and its downstream effectors mammalian target of rapamycin (mTOR) and p70 S6 kinase (p70^S6K) were strongly attenuated. An in silico study further demonstrated that ETD binds to the protein kinase domain of Akt with both hydrogen bonding and van der Waals interactions. In addition, an in vivo tail vein injection metastasis study demonstrated a significant effect of ETD on the suppression of lung cancer cell metastasis. This study provides preclinical information regarding ETD, which exhibits promising antimetastatic activity against non-small-cell lung cancer through Akt/mTOR/p70^S6K-induced actin reorganization and MMPs expression.

Articular Chondrocyte Phenotype Regulation through the Cytoskeleton and the Signaling Processes That Originate from or Converge on the Cytoskeleton: Towards a Novel Understanding of the Intersection between Actin Dynamics and Chondrogenic Function

Numerous studies have assembled a complex picture, in which extracellular stimuli and intracellular signaling pathways modulate the chondrocyte phenotype. Because many diseases are mechanobiology-related, this review asked to what extent phenotype regulators control chondrocyte function through the cytoskeleton and cytoskeleton-regulating signaling processes. Such information would generate leverage for advanced articular cartilage repair. Serial passaging, pro-inflammatory cytokine signaling (TNF-α, IL-1α, IL-1β, IL-6, and IL-8), growth factors (TGF-α), and osteoarthritis not only induce dedifferentiation but also converge on RhoA/ROCK/Rac1/mDia1/mDia2/Cdc42 to promote actin polymerization/crosslinking for stress fiber (SF) formation. SF formation takes center stage in phenotype control, as both SF formation and SOX9 phosphorylation for COL2 expression are ROCK activity-dependent. Explaining how it is molecularly possible that dedifferentiation induces low COL2 expression but high SF formation, this review theorized that, in chondrocyte SOX9, phosphorylation by ROCK might effectively be sidelined in favor of other SF-promoting ROCK substrates, based on a differential ROCK affinity. In turn, actin depolymerization for redifferentiation would “free-up” ROCK to increase COL2 expression. Moreover, the actin cytoskeleton regulates COL1 expression, modulates COL2/aggrecan fragment generation, and mediates a fibrogenic/catabolic expression profile, highlighting that actin dynamics-regulating processes decisively control the chondrocyte phenotype. This suggests modulating the balance between actin polymerization/depolymerization for therapeutically controlling the chondrocyte phenotype.

Changes in the tumor microenvironment and outcome for TME-targeting therapy in glioblastoma: A pilot study

Glioblastoma (GBM) is a hypervascular and aggressive primary malignant tumor of the central nervous system. Recent investigations showed that traditional therapies along with antiangiogenic therapies failed due to the development of post-therapy resistance and recurrence. Previous investigations showed that there were changes in the cellular and metabolic compositions in the tumor microenvironment (TME). It can be said that tumor cell-directed therapies are ineffective and rethinking is needed how to treat GBM. It is hypothesized that the composition of TME-associated cells will be different based on the therapy and therapeutic agents, and TME-targeting therapy will be better to decrease recurrence and improve survival. Therefore, the purpose of this study is to determine the changes in the TME in respect of T-cell population, M1 and M2 macrophage polarization status, and MDSC population following different treatments in a syngeneic model of GBM. In addition to these parameters, tumor growth and survival were also studied following different treatments. The results showed that changes in the TME-associated cells were dependent on the therapeutic agents, and the TME-targeting therapy improved the survival of the GBM bearing animals. The current GBM therapies should be revisited to add agents to prevent the accumulation of bone marrow-derived cells in the TME or to prevent the effect of immune-suppressive myeloid cells in causing alternative neovascularization, the revival of glioma stem cells, and recurrence. Instead of concurrent therapy, a sequential strategy would be better to target TME-associated cells.

Drug repurposing towards targeting cancer stem cells in pediatric brain tumors

In the pediatric population, brain tumors represent the most commonly diagnosed solid neoplasms and the leading cause of cancer-related deaths globally. They include low-grade gliomas (LGGs), medulloblastomas (MBs), and other embryonal, ependymal, and neuroectodermal tumors. The mainstay of treatment for most brain tumors includes surgical intervention, radiation therapy, and chemotherapy. However, resistance to conventional therapy is widespread, which contributes to the high mortality rates reported and lack of improvement in patient survival despite advancement in therapeutic research. This has been attributed to the presence of a subpopulation of cells, known as cancer stem cells (CSCs), which reside within the tumor bulk and maintain self-renewal and recurrence potential of the tumor. An emerging promising approach that enables identifying novel therapeutic strategies to target CSCs and overcome therapy resistance is drug repurposing or repositioning. This is based on using previously approved drugs with known pharmacokinetic and pharmacodynamic characteristics for indications other than their traditional ones, like cancer. In this review, we provide a synopsis of the drug repurposing methodologies that have been used in pediatric brain tumors, and we argue how this selective compilation of approaches, with a focus on CSC targeting, could elevate drug repurposing to the next level.

Naringenin Sensitizes Resistant C6 Glioma Cells with a Repressive Impact on the Migrating Ability

Background:

Glioma, the most common form of a malignant brain tumour is characterised by a poor prognosis, which is attributable to its resistance against current therapeutic approaches. Temozolomide (TMZ), a DNA alkylating agent, is the first-line drug for glioma treatment. Long-term treatment using TMZ was reported to culminate in the development of resistance with overexpression of multidrug resistance 1 gene coded protein P-glycoprotein, which in turn releases the drugs from the tumour cells.

Purpose:

Thus, to circumvent such resistance issues, the current study attempted to explore the effect of naringenin (a flavanone) with proven antiglial tumour potential, in mitigating the features of TMZ resistance.

Methods:

Colony-forming assay, invasion assay and scratch wound assay were performed among the groups, namely tumour control (C6), vehicle control (V), naringenin (NGEN)-treated, drug-resistant tumour cells (C6R), and drug resistance cells added with NGEN (C6R+NGEN), to examine the impact of NGEN on migration and invasion. The effect of NGEN on filopodia length and density during cell migration was also studied in addition to the matrix metalloproteinases (MMP-2 and MMP-9) and p-ERK levels.

Results and Conclusion:

NGEN and C6R+NGEN groups had shown significant reduction (P < .01) in length and density of filopodia, colony formation, invasion and wound healing. Further, NGEN could also modify the assessed protein levels (P < .001), which were involved in migration and invasion in sensitive and resistant cells. Our study had provided the first evidence on NGEN-induced enhanced sensitivity against TMZ resistance with profound influence as an antimigratory and anti-invasive agent.

Hyperplasia suppressor gene inhibits the proliferation and metastasis of glioma cells by targeting rho family proteins

AIM

To investigate the effect of the hyperplasia suppressor gene (HSG) on human glioma cell invasion and its possible mechanism.

METHODS

Human glioma U251 cells were infected with recombinant viral vectors carrying the HSG gene sequence (HSG overexpression group) and HSG interference sequence (HSG suppression group). The negative control group with no-load virus transcription and a blank control group with only PBS treatment were set up. CCK-8 assay, cell scratch healing test, transwell migration, and invasion test were used to detect the effect of HSG expression on proliferation, migration and invasion of U251 glioma cells. Cell immunofluorescence and cell adhesion test were used to analyze the effect of HSG expression on cytoskeleton formation and adhesion ability of U251 cells. Gene chip technology was employed to preliminarily explore the effect of HSG expression change on the inherent gene expression in U251 cells. The expression of Rho family key molecule mRNA and protein was detected by light quantitative PCR and western blot.

RESULTS

After 24 h of transcription with the recombinant virus vector, the cells showed a green color under an inverted fluorescence microscope. HSG expression increased in the HSG overexpression group (P < 0.01), and decreased in the HSG inhibition group (P < 0.01). Compared with the two control groups, the proliferation, scratch healing rate, migrating cell number, invasive cell number and adhesion cell number in the HSG overexpression group were markedly lower. After HSG overexpression, the morphology of U251 cells changed; filamentous pseudopods shortened and partially flaked. However, after HSG inhibition, the pseudopods grew toward both ends and were arranged axially. The overexpression of HSG inhibited the expression of rho family proteins (RhoA, Rock1, Rock2, Rac1, and Cdc42).

CONCLUSION

The overexpression of HSG inhibits the progression of glioma U251 cells by regulating the expression of rho family proteins.

Emerging therapeutic potential of anti-psychotic drugs in the management of human glioma: A comprehensive review

Despite numerous advancements in the last decade, human gliomas such as astrocytoma and glioblastoma multiforme have the worst prognoses among all cancers. Anti-psychotic drugs are commonly prescribed to treat mental disorders among cancer patients, and growing empirical evidence has revealed their antitumor, anti-metastatic, anti-angiogenic, anti-proliferative, chemo-preventive, and neo-adjuvant efficacies in various in vitro, in vivo, and clinical glioma models. Anti-psychotic drugs have drawn the attention of physicians and researchers owing to their beneficial effects in the prevention and treatment of gliomas. This review highlights data on the therapeutic potential of various anti-psychotic drugs as anti-proliferative, chemopreventive, and anti-angiogenic agents in various glioma models via the modulation of upstream and downstream molecular targets involved in apoptosis, autophagy, oxidative stress, inflammation, and the cell cycle in in vitro and in vivo preclinical and clinical stages among glioma patients. The ability of anti-psychotic drugs to modulate various signaling pathways and multidrug resistance-conferring proteins that enhance the efficacy of chemotherapeutic drugs with low side-effects exemplifies their great potential as neo-adjuvants and potential chemotherapeutics in single or multimodal treatment approach. Moreover, anti-psychotic drugs confer the ability to induce glioma into oligodendrocyte-like cells and neuronal-like phenotype cells with reversal of epigenetic alterations through inhibition of histone deacetylase further rationalize their use in glioma treatment. The improved understanding of anti-psychotic drugs as potential chemotherapeutic drugs or as neo-adjuvants will provide better information for their use globally as affordable, well-tolerated, and effective anticancer agents for human glioma.

Anticancer activity of paroxetine in human colon cancer cells: Involvement of MET and ERBB3

The concept of drug repositioning has recently received considerable attention in the field of oncology. In the present study, we propose that paroxetine can be used as a potent anticancer drug. Paroxetine, one of the selective serotonin reuptake inhibitors (SSRIs), has been widely prescribed for the treatment of depression and anxiety disorders. Recently, SSRIs have been reported to have anticancer activity in various types of cancer cells; however, the underlying mechanisms of their action are not yet known. In this study, we investigated the potential anticancer effect of paroxetine in human colorectal cancer cells, HCT116 and HT‐29. Treatment with paroxetine reduced cell viability, which was associated with marked increase in apoptosis, in both the cell lines. Also, paroxetine effectively inhibited colony formation and 3D spheroid formation. We speculated that the mode of action of paroxetine might be through the inhibition of two major receptor tyrosine kinases – MET and ERBB3 – leading to the suppression of AKT, ERK and p38 activation and induction of JNK and caspase‐3 pathways. Moreover, in vivo experiments revealed that treatment of athymic nude mice bearing HT‐29 cells with paroxetine remarkably suppressed tumour growth. In conclusion, paroxetine is a potential therapeutic option for patients with colorectal cancer.

Challenges in the Treatment of Glioblastoma: Multisystem Mechanisms of Therapeutic Resistance

Glioblastoma is one of the most lethal human cancers, with poor survival despite surgery, radiation treatment, and chemotherapy. Advances in the treatment of this type of brain tumor are limited because of several resistance mechanisms. Such mechanisms involve limited drug entry into the central nervous system compartment by the blood-brain barrier and by actions of the normal brain to counteract tumor-targeting medications. In addition, the vast heterogeneity in glioblastoma contributes to significant therapeutic resistance by preventing adequate control of the entire tumor mass by a single drug and by facilitating escape mechanisms from targeted agents. The stem cell-like characteristics of glioblastoma promote resistance to chemotherapy, radiation, and immunotherapy through upregulation of efflux transporters, promotion of glioblastoma stem cell proliferation in neurogenic zones, and immune suppression, respectively. Metabolic cascades in glioblastoma prevent effective treatments through the optimization of glucose use, the use of alternative nutrient precursors for energy production, and the induction of hypoxia to enhance tumor growth. In the era of precision medicine, an assortment of molecular techniques is being developed to target an individual's unique tumor, with the hope that this personalized strategy will bypass therapeutic resistance. Although each resistance mechanism presents an array of challenges to effective treatment of glioblastoma, as the field recognizes and addresses these difficulties, future treatments may have more efficacy and promise for patients with glioblastoma.

Mechanisms of invasion and motility of high-grade gliomas in the brain

High-grade gliomas are especially difficult tumors to treat due to their invasive behavior. This has led to extensive research focusing on arresting glioma cell migration. Cell migration involves the sensing of a migratory cue, followed by polarization in the direction of the cue, and reorganization of the actin cytoskeleton to allow for a protrusive leading edge and a contractile trailing edge. Transmission of these forces to produce motility also requires adhesive interactions of the cell with the extracellular microenvironment. In glioma cells, transmembrane receptors such as CD44 and integrins bind the cell to the surrounding extracellular matrix that provides a substrate on which the cell can exert the requisite forces for cell motility. These various essential parts of the migratory machinery are potential targets to halt glioma cell invasion. In this review, we discuss the mechanisms of glioma cell migration and how they may be targeted in anti-invasion therapies.

Depression and glioblastoma, complicated concomitant diseases: a systemic review of published literature

Glioblastoma multiforme (GBM) is the most common primary brain cancer. Depression is a common co-morbidity of this condition. Despite this common interaction, relatively little research has been performed on the development of GBM-associated depression. We performed a literary search of the PubMed database for articles published relating to GBM and depression. A total of 85 articles were identified with 46 meeting inclusion criteria. Depression significantly impacts care, decreasing medication compliance, and patient survival. Diagnostically, because depression and GBM share intricate neuro-connectivity in a way that effect functionality, these diseases can be mistaken for alternative psychological or pathological disorders, complicating care. Therapeutically, anti-depressants have anti-tumor properties; yet, some have been shown to interfere with GBM treatment. One reason for this is that the pathophysiological development of depression and GBM share several pathways including altered regulation of the 5-HT receptor, norepinephrine, and 3':5'-cyclic monophosphate. Over time, depression can persist after GBM treatment, affecting patient quality of life. Together, depression and GBM are complicated concomitant diseases. Clinicians must be aware of their co-existence. Because of overlapping molecular pathways involved in both diseases, careful medication selection is imperative to avoid potential adverse interactions. Since GBMs are the most common primary brain cancer, physicians dealing with this disease should be prepared for the development of depression as a potential sequela of this condition, given the related pathophysiology and the known poor outcomes.

Actin, alpha, cardiac muscle 1 (ACTC1) knockdown inhibits the migration of glioblastoma cells in vitro

BACKGROUND

Recurrence is inevitable in glioblastomas (GBMs) and requires multifactorial processes. One of the factors that cause recurrence is the strong migratory capacity of GBM cells. We recently reported that actin, alpha, cardiac muscle 1 (ACTC1) could serve as a marker to detect GBM migration in clinical cases.

OBJECTIVE

This study aimed to clarify whether the knockdown of highly expressed ACTC1 can inhibit the migratory capacity of cells in the GBM cell line.

METHODS

ACTC1 expression was examined using immunocytochemistry and droplet digital polymerase chain reaction. The motility of GBM cells that were either treated with siRNA to knock down ACTC1 or untreated were investigated using a time-lapse study in vitro.

RESULTS

The relatively high ACTC1 expression was confirmed in a GBM cell line, i.e., U87MG. The ACTC1 expression in U87MG cells was significantly inhibited by ACTC1-siRNA (p < 0.05). A cell movement tracking assay using time-lapse imaging demonstrated the inhibition of U87MG cell migration by ACTC1 knockdown. The quantitative cell migration analysis demonstrated that the distance traversed during 72 h was 3607 ± 458 (median ± SD) μm by untreated U87MG cells and 3570 ± 748 μm by negative control siRNA-treated cells. However, the distance migrated by ACTC1-siRNA-treated cells during 72 h was significantly shorter (1265 ± 457 μm, p < 0.01) than the controls.

CONCLUSION

ACTC1 knockdown inhibits U87MG cell migration.

Repurposing drugs for glioblastoma: From bench to bedside

Glioblastoma multiforme is the most common, aggressive and lethal type of brain tumor. It is a stage IV cancer disease with a poor prognosis, as the current therapeutic options (surgery, radiotherapy and chemotherapy) are not able to eradicate tumor cells. The approach to treat glioblastoma has not suffered major changes over the last decade and temozolomide (TMZ) remains the mainstay for chemotherapy. However, resistance mechanisms to TMZ and other chemotherapeutic agents are becoming more frequent. The lack of effective options is a reality that may be counterbalanced by repositioning known and commonly used drugs for other diseases. This approach takes into consideration the available pharmacokinetic, pharmacodynamic, toxicity and safety data, and allows a much faster and less expensive drug and product development process. In this review, an extensive literature search is conducted aiming to list drugs with repurposing usage, based on their preferential damage in glioblastoma cells through various mechanisms. Some of these drugs have already entered clinical trials, exhibiting favorable outcomes, which sparks their potential application in glioblastoma treatment.

Drug Repositioning in Glioblastoma: A Pathway Perspective

Glioblastoma multiforme (GBM) is the most malignant primary adult brain tumor. The current standard of care is surgical resection, radiation, and chemotherapy treatment, which extends life in most cases. Unfortunately, tumor recurrence is nearly universal and patients with recurrent glioblastoma typically survive <1 year. Therefore, new therapies and therapeutic combinations need to be developed that can be quickly approved for use in patients. However, in order to gain approval, therapies need to be safe as well as effective. One possible means of attaining rapid approval is repurposing FDA approved compounds for GBM therapy. However, candidate compounds must be able to penetrate the blood-brain barrier (BBB) and therefore a selection process has to be implemented to identify such compounds that can eliminate GBM tumor expansion. We review here psychiatric and non-psychiatric compounds that may be effective in GBM, as well as potential drugs targeting cell death pathways. We also discuss the potential of data-driven computational approaches to identify compounds that induce cell death in GBM cells, enabled by large reference databases such as the Library of Integrated Network Cell Signatures (LINCS). Finally, we argue that identifying pathways dysregulated in GBM in a patient specific manner is essential for effective repurposing in GBM and other gliomas.

Role of Microenvironment in Glioma Invasion: What We Learned from In Vitro Models

The invasion properties of glioblastoma hamper a radical surgery and are responsible for its recurrence. Understanding the invasion mechanisms is thus critical to devise new therapeutic strategies. Therefore, the creation of in vitro models that enable these mechanisms to be studied represents a crucial step. Since in vitro models represent an over-simplification of the in vivo system, in these years it has been attempted to increase the level of complexity of in vitro assays to create models that could better mimic the behaviour of the cells in vivo. These levels of complexity involved: 1. The dimension of the system, moving from two-dimensional to three-dimensional models; 2. The use of microfluidic systems; 3. The use of mixed cultures of tumour cells and cells of the tumour micro-environment in order to mimic the complex cross-talk between tumour cells and their micro-environment; 4. And the source of cells used in an attempt to move from commercial lines to patient-based models. In this review, we will summarize the evidence obtained exploring these different levels of complexity and highlighting advantages and limitations of each system used.

Tricyclic Antidepressants Modulate Stressed Mitochondria in Glioblastoma Multiforme Cells

A common feature of solid tumors, including glioblastoma multiforme (GBM), is mitochondrial dysfunction. However, it is reported that the current standard of anti-GBM therapies may potentiate mitochondrial damage and, in effect, support the aggressive character of cancer. As mitochondria are implicated in the modulation of cellular drug sensitivity and chemoresistance mechanisms, activation-stressed mitochondria in GBM cells may represent a new target for anti-GBM therapy that is nontoxic for normal cells.

METHODS

As mitochondria are possible targets for antidepressant drugs used as adjuvant therapy in patients with GBM, we examined their influence on mitochondrial volume and activity, reactive oxygen species level, extracellular lactate concentration, and p65 NF-κB gene expression in GBM cells.

RESULTS

Our investigation showed, for the first time, that tricyclic antidepressants, imipramine and amitriptyline, partially reverse GBM abnormalities.

CONCLUSION

In the light of reported studies, the mitochondrial disturbance observed in glioma cells is a dynamic process that can be reversed or silenced. Moreover, imipramine and amitriptyline are attractive cellular metabolic modulators and can potentially be used to restoring a proper function of mitochondria in GBM cells.

Identification of antipsychotic drug fluspirilene as a potential anti-glioma stem cell drug

Glioma stem cell (GSC)-targeted therapy is expected to be one of the most innovative approaches to treat patients with glioblastoma (GBM). A number of the drugs that restrain the signaling pathway essential for GSC maintenance have been under clinical trials. Here, we identified fluspirilene, a traditional antipsychotic drug, as a GSC-targeting agent, selected from thousands of existing drugs, and investigated its therapeutic effects against GBM with the purpose of drug repositioning. To develop novel therapeutics targeting GSCs, we initially screened drug libraries for small-molecule compounds showing a greater efficacy, compared to that of controls, in inhibiting the proliferation and survival of different GSC lines using cell proliferation assay. Drugs already reported to show therapeutic effects against GBM or those under clinical trials were excluded from subsequent screening. Finally, we found three drugs showing remarkable antiproliferative effects on GSCs at low concentrations and investigated their therapeutic effects on GSCs, glioma cell lines, and in a GBM mouse model. Of the three compounds, fluspirilene demonstrated a significant inhibitory effect on the proliferation and invasion of glioma cells as well as in the model mice treated with the drug. These effects were associated with the inactivation of the signal transducer and activator of transcription 3 (STAT3). Redeveloping of fluspirilene is a promising approach for the treatment of GBM.

Fibroblast growth factor 13 regulates glioma cell invasion and is important for bevacizumab-induced glioma invasion

Glioblastoma has the poorest prognosis, and is characterized by excessive invasion and angiogenesis. To determine the invasive mechanisms, we previously used two glioma cell lines (J3T-1 and J3T-2) with different invasive phenotypes. The J3T-1 showed abundant angiogenesis and tumor cell invasion around neovasculature, while J3T-2 showed diffuse cell infiltration into surrounding healthy parenchyma. Microarray analyses were used to identify invasion-related genes in J3T-2 cells, and the expressed genes and their intracellular and intratumoral distribution patterns were evaluated in J3T-2 cell lines, human glioma cell lines, human glioblastoma stem cells and human glioblastoma specimens. To determine the role of the invasion-related genes, invasive activities were evaluated in vitro and in vivo. Fibroblast growth factor 13 (FGF13) was overexpressed in J3T-2 cells compared to J3T-1 cells, and in human glioma cell lines, human glioblastoma stem cells and human glioblastoma specimens, when compared to that of normal human astrocytes. Immunohistochemical staining and the RNA-seq (sequencing) data from the IVY Glioblastoma Atlas Project showed FGF13 expression in glioma cells in the invasive edges of tumor specimens. Also, the intracellular distribution was mainly in the cytoplasm of tumor cells and colocalized with tubulin. Overexpression of FGF13 stabilized tubulin dynamics in vitro and knockdown of FGF13 decreased glioma invasion both in vitro and in vivo and prolonged overall survival of several xenograft models. FGF13 was negatively regulated by hypoxic condition. Silencing of FGF13 also decreased in vivo bevacizumab-induced glioma invasion. In conclusion, FGF13 regulated glioma cell invasion and bevacizumab-induced glioma invasion, and could be a novel target for glioma treatment.

Anti-GD2-ch14.18/CHO coated nanoparticles mediate glioblastoma (GBM)-specific delivery of the aromatase inhibitor, Letrozole, reducing proliferation, migration and chemoresistance in patient-derived GBM tumor cells

Aromatase is a critical enzyme in the irreversible conversion of androgens to oestrogens, with inhibition used clinically in hormone-dependent malignancies. We tested the hypothesis that targeted aromatase inhibition in an aggressive brain cancer called glioblastoma (GBM) may represent a new treatment strategy. In this study, aromatase inhibition was achieved using third generation inhibitor, Letrozole, encapsulated within the core of biodegradable poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs). PLGA-NPs were conjugated to human/mouse chimeric anti-GD2 antibody ch14.18/CHO, enabling specific targeting of GD2-positive GBM cells. Treatment of primary and recurrent patient-derived GBM cells with free-Letrozole (0.1 μM) led to significant decrease in cell proliferation and migration; in addition to reduced spheroid formation. Anti-GD2-ch14.18/CHO-NPs displayed specific targeting of GBM cells in colorectal-glioblastoma co-culture, with subsequent reduction in GBM cell numbers when treated with anti-GD2-ch14.18-PLGA-Let-NPs in combination with temozolomide. As miR-191 is an estrogen responsive microRNA, its expression, fluctuation and role in Letrozole treated GBM cells was evaluated, where treatment with premiR-191 was capable of rescuing the reduced proliferative phenotype induced by aromatase inhibitor. The repurposing and targeted delivery of Letrozole for the treatment of GBM, with the potential role of miR-191 identified, provides novel avenues for target assessment in this aggressive brain cancer.

Knockdown of Collagen Triple Helix Repeat Containing 1 (CTHRC1) Inhibits Epithelial-Mesenchymal Transition and Cellular Migration in Glioblastoma Cells

Collagen triple helix repeat containing 1 (CTHRC1), an extracellular matrix-related protein, has been found to be upregulated in many solid tumors and contributes to tumorigenesis. We found that CTHRC1 is overexpressed in glioblastoma tissues and cells. By using the technique of RNA interference, the expression of CTHRC1 in the human glioblastoma U-87MG cell line was downregulated, and the proliferation and migration of U-87MG cells were examined. The results showed that the knockdown of CTHRC1 exerts inhibitory effects on the proliferation and migration ability of U-87MG cells. Knockdown of CTHRC1 expression in U-87MG cells resulted in upregulation in the expression of E-cadherin and downregulation in the expression of N-cadherin, SNAIL, and Slug, suggesting that CTHRC1 inhibits glioblastoma cell migration by suppressing epithelial–mesenchymal transition (EMT). Knockdown of CTHRC1 led to remarkably decreased β-catenin protein levels in the nucleus. These results indicate that CTHRC1 might play an important role in the development of glioblastoma and offer a candidate molecular target for glioblastoma prevention and therapy.