Fluoxetine, an antidepressant, suppresses glioblastoma by evoking AMPAR-mediated calcium-dependent apoptosis

SKF96365 Inhibits Tumor Proliferation by Inducing Apoptosis and Autophagy in Human Esophageal Squamous Cell Carcinoma

Calcium channel blockers are emerging as a new generation of attractive anticancer drugs. SKF96365, originally thought to be a store-operated calcium entry (SOCE) inhibitor, is now often used as a TRPC channel blocker and is widely used in medical diagnostics. SKF96365 has shown antitumor effects on a variety of cancer cell lines. The objective of this study was to investigate the anticancer effect of SKF96365 on esophageal cancer in vivo and in vitro. Cell Counting Kit-8 (CCK-8) and colony formation were used to test the proliferation inhibition of SKF96365 on cell lines. Western blot and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to detect cell apoptosis rates. In addition, we demonstrated the antitumor effect of SKF96365 in vivo in xenografted mice. As a result, SKF96365 significantly inhibited the proliferation of K510, K30, and EC9706 in vitro. SKF96365 induces apoptosis in three cell lines through the poly(adenosine diphosphate-ribose) polymerase (PARP), caspase-9, and BCL-2 pathways in a dose-dependent and time-dependent manner. Moreover, SKF96365 treatment also induced apoptosis and inhibited tumor growth in nude mice. The calcium channel TRPC1 was significantly downregulated by SKF96365. Autophagy was also induced during the treatment of SKF96365. In summary, SKF96365 induces apoptosis (PARP, caspase-9, and BCL-2) and autophagy (LC3-A/B) by inhibiting TRPC1 in esophageal cancer cells, thereby inhibiting tumor growth.

Beyond Psychotropic: Potential Repurposing of Fluoxetine toward Cancer Therapy

Drug repurposing, rebranding an existing drug for a new therapeutic indication, is deemed a beneficial approach for a quick and cost-effective drug discovery process by skipping preclinical, Phase 1 trials and pharmacokinetic studies. Several psychotropic drugs, including selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), were studied for their potential application in different diseases, especially in cancer therapy. Fluoxetine (FLX) is one of the most prescribed psychotropic agents from the SSRIs class for the treatment of several neuropsychiatric disorders with a favorable safety profile. FLX exhibited different oncolytic effects via mechanisms distinct from its main serotonergic activity. Taking advantage of its ability to rapidly penetrate the blood-brain barrier, FLX could be particularly useful in brain tumors. This was proved by different in vitro and in vivo experiments using FLX as a monotherapy or combination with temozolomide (TMZ) or radiotherapy. In this review of the literature, we summarize the potential pleiotropic oncolytic roles of FLX against different cancers, highlighting the multifaceted activities of FLX and its ability to interrupt cancer proliferation via several molecular mechanisms and even surmount multidrug resistance (MDR). We elaborated on the successful synergistic combinations such as FXR/temozolomide and FXR/raloxifene for the treatment of glioblastoma and breast cancer, respectively. We showcased beneficial pharmaceutical trials to load FLX onto carriers to enhance its safety and efficacy on cancer cells. This is the first review article extensively summarizing all previous FLX repurposing studies for the management of cancer.

Role of Serotonergic System in Regulating Brain Tumor-Associated Neuroinflammatory Responses

Serotonin signaling regulates wide arrays of both neural and extra-neural functions. Serotonin is also found to affect cancer progression directly as well as indirectly by modulating the immune cells. In the brain, serotonin plays a key role in regulating various functions; disturbance of the normal activities of serotonin leads to various mental illnesses, including the neuroinflammatory response in the central nervous system (CNS). The neuroinflammatory response can be initiated in various psychological illnesses and brain cancer. Serotonergic signaling can impact the functions of both glial as well as the immune cells. It can also affect the tumor immune microenvironment and the inflammatory response associated with brain cancers. Apart from this, many drugs used for treatment of psychological illness are known to modulate serotonergic system and can cross the blood-brain barrier. Understanding the role of serotonergic pathways in regulating neuroinflammatory response and brain cancer will provide a new paradigm in modulating the serotonergic components in treating brain cancer and associated inflammation-induced brain damages.

Novel therapeutic strategies in glioma targeting glutamatergic neurotransmission

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

STAC1 is required for glioblastoma cell invasion and survival

Glioblastoma Multiforme (GBM) is a highly malignant brain tumor with poor prognosis. Understanding the molecular mechanisms driving GBM tumorigenesis is crucial for developing effective therapeutic strategies. This study investigates the role of STAC1, a gene belonging to the SH3 and cysteine-rich domain family, in glioblastoma cell invasion and survival. Computational analyses of patient samples reveal that STAC1 expression is elevated in GBM tissues, and higher STAC1 expression is associated with lower overall survival rates. Consistently, we find that overexpression of STAC1 in glioblastoma cells enhances invasion, while knockdown of STAC1 reduces invasion and the expression of genes associated with epithelial-to-mesenchymal transition (EMT). STAC1 depletion also induces apoptosis in glioblastoma cells. Furthermore, we show that STAC1 regulates AKT and calcium channel signaling in glioblastoma cells. Collectively, our study provides valuable insights into the pathogenic roles of STAC1 in GBM and highlights its potential as a promising target for the treatment of high-grade glioblastoma.

Association between Fluoxetine Use and Overall Survival among Patients with Cancer Treated with PD-1/L1 Immunotherapy

Checkpoint inhibitors can be a highly effective antitumor therapy but only to a subset of patients, presumably due to immunotherapy resistance. Fluoxetine was recently revealed to inhibit the NLRP3 inflammasome, and NLRP3 inhibition could serve as a target for immunotherapy resistance. Therefore, we evaluated the overall survival (OS) in patients with cancer receiving checkpoint inhibitors combined with fluoxetine. A cohort study was conducted among patients diagnosed with lung, throat (pharynx or larynx), skin, or kidney/urinary cancer treated with checkpoint inhibitor therapy. Utilizing the Veterans Affairs Informatics and Computing Infrastructure, patients were retrospectively evaluated during the period from October 2015 to June 2021. The primary outcome was overall survival (OS). Patients were followed until death or the end of the study period. There were 2316 patients evaluated, including 34 patients who were exposed to checkpoint inhibitors and fluoxetine. Propensity score weighted Cox proportional hazards demonstrated a better OS in fluoxetine-exposed patients than unexposed (HR: 0.59, 95% CI 0.371-0.936). This cohort study among cancer patients treated with checkpoint inhibitor therapy showed a significant improvement in the OS when fluoxetine was used. Because of this study's potential for selection bias, randomized trials are needed to assess the efficacy of the association of fluoxetine or another anti-NLRP3 drug to checkpoint inhibitor therapy.

The application of antidepressant drugs in cancer treatment

Antidepressants refer to psychotropic drugs which are used to treat mental illness with prominent emotional depression symptoms. It was reported that antidepressants had associated with anti-carcinogenic function which was associated with various signaling pathways and changing of microenvironment. Its mechanism includes cell apoptosis, antiproliferative effects, mitochondria-mediated oxidative stress, DNA damaging, changing of immune response and inflammatory conditions, and acting by inhibiting multidrug resistance of cancer cells. Accumulated studies showed that antidepressants influenced the metabolic pathway of tumor cells. This review summarized recent developments with the impacts and mechanisms of 10 kinds of antidepressants in carcinostasis. Antidepressants are also used in combination therapy with typical anti-tumor drugs which shows a synergic effect in anti-tumor. By contrast, the promotion roles of antidepressants in increasing cancer recurrence risk, mortality, and morbidity are also included. Further clinical experiments and mechanism analyses needed to be achieved. A full understanding of the underlying mechanisms of antidepressants-mediated anticarcinogenic effects may provide new clues for cancer prevention and clinical treatment.

Role of nerves in neurofibromatosis type 1-related nervous system tumors

BACKGROUND

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder that affects nearly 1 in 3000 infants. Neurofibromin inactivation and NF1 gene mutations are involved in various aspects of neuronal function regulation, including neuronal development induction, electrophysiological activity elevation, growth factor expression, and neurotransmitter release. NF1 patients often exhibit a predisposition to tumor development, especially in the nervous system, resulting in the frequent occurrence of peripheral nerve sheath tumors and gliomas. Recent evidence suggests that nerves play a role in the development of multiple tumor types, prompting researchers to investigate the nerve as a vital component in and regulator of the initiation and progression of NF1-related nervous system tumors.

CONCLUSION

In this review, we summarize existing evidence about the specific effects of NF1 mutation on neurons and emerging research on the role of nerves in neurological tumor development, promising a new set of selective and targeted therapies for NF1-related tumors.

Neurotransmitters: Potential Targets in Glioblastoma

Simple Summary

Aiming to discover potential treatments for GBM, this review connects emerging research on the roles of neurotransmitters in the normal neural and the GBM microenvironments and sheds light on the prospects of their application in the neuropharmacology of GBM. Conventional therapy is blamed for its poor effect, especially in inhibiting tumor recurrence and invasion. Facing this dilemma, we focus on neurotransmitters that modulate GBM initiation, progression and invasion, hoping to provide novel therapy targeting GBM. By analyzing research concerning GBM therapy systematically and scientifically, we discover increasing insights into the regulatory effects of neurotransmitters, some of which have already shown great potential in research in vivo or in vitro. After that, we further summarize the potential drugs in correlation with previously published research. In summary, it is worth expecting that targeting neurotransmitters could be a promising novel pharmacological approach for GBM treatment.

Abstract

For decades, glioblastoma multiforme (GBM), a type of the most lethal brain tumor, has remained a formidable challenge in terms of its treatment. Recently, many novel discoveries have underlined the regulatory roles of neurotransmitters in the microenvironment both physiologically and pathologically. By targeting the receptors synaptically or non-synaptically, neurotransmitters activate multiple signaling pathways. Significantly, many ligands acting on neurotransmitter receptors have shown great potential for inhibiting GBM growth and development, requiring further research. Here, we provide an overview of the most novel advances concerning the role of neurotransmitters in the normal neural and the GBM microenvironments, and discuss potential targeted drugs used for GBM treatment.

Drug Repurposing, a Fast-Track Approach to Develop Effective Treatments for Glioblastoma

Glioblastoma (GBM) remains one of the most difficult tumors to treat. The mean overall survival rate of 15 months and the 5-year survival rate of 5% have not significantly changed for almost 2 decades. Despite progress in understanding the pathophysiology of the disease, no new effective treatments to combine with radiation therapy after surgical tumor debulking have become available since the introduction of temozolomide in 1999. One of the main reasons for this is the scarcity of compounds that cross the blood-brain barrier (BBB) and reach the brain tumor tissue in therapeutically effective concentrations. In this review, we focus on the role of the BBB and its importance in developing brain tumor treatments. Moreover, we discuss drug repurposing, a drug discovery approach to identify potential effective candidates with optimal pharmacokinetic profiles for central nervous system (CNS) penetration and that allows rapid implementation in clinical trials. Additionally, we provide an overview of repurposed candidate drug currently being investigated in GBM at the preclinical and clinical levels. Finally, we highlight the importance of phase 0 trials to confirm tumor drug exposure and we discuss emerging drug delivery technologies as an alternative route to maximize therapeutic efficacy of repurposed candidate drug.

Integrative genomic analysis of a novel small nucleolar RNAs prognostic signature in patients with acute myelocytic leukemia

This study mainly used The Cancer Genome Atlas (TCGA) RNA sequencing dataset to screen prognostic snoRNAs of acute myeloid leukemia (AML), and used for the construction of prognostic snoRNAs signature for AML. A total of 130 AML patients with RNA sequencing dataset were used for prognostic snoRNAs screenning. SnoRNAs co-expressed genes and differentially expressed genes (DEGs) were used for functional annotation, as well as gene set enrichment analysis (GSEA). Connectivity Map (CMap) also used for potential targeted drugs screening. Through genome-wide screening, we identified 30 snoRNAs that were significantly associated with the prognosis of AML. Then we used the step function to screen a prognostic signature composed of 14 snoRNAs (SNORD72, SNORD38, U3, SNORA73B, SNORD79, SNORA73, SNORD12B, SNORA74, SNORD116-12, SNORA65, SNORA14, snoU13, SNORA75, SNORA31), which can significantly divide AML patients into high- and low-risk groups. Through GSEA, snoRNAs co-expressed genes and DEGs functional enrichment analysis, we screened a large number of potential functional mechanisms of this prognostic signature in AML, such as phosphatidylinositol 3-kinase-Akt, Wnt, epithelial to mesenchymal transition, T cell receptors, NF-kappa B, mTOR and other classic cancer-related signaling pathways. In the subsequent targeted drug screening using CMap, we also identified six drugs that can be used for AML targeted therapy, they were alimemazine, MG-262, fluoxetine, quipazine, naltrexone and oxybenzone. In conclusion, our current study was constructed an AML prognostic signature based on the 14 prognostic snoRNAs, which may serve as a novel prognostic biomarker for AML.

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.

Opportunities for Drug Repurposing of Serotonin Reuptake Inhibitors: Potential Uses in Inflammation, Infection, Cancer, Neuroprotection, and Alzheimer's Disease Prevention

Serotonin reuptake inhibitors (SRIs) are safe and widely used for a variety of indications including depressive disorders, anxiety, and chronic pain. Besides inhibiting the serotonin transporter, these medications have broad-spectrum properties in many systems. Their roles have been studied in cancer, Alzheimer's disease, and infectious processes. The COVID-19 pandemic highlighted the importance of drug repurposing of medications already in use. We conducted a narrative review of current evidence and ongoing research on drug repurposing of SRIs, with a focus on immunomodulatory, antiproliferative, and neuroprotective activity. SRIs may have clinical use as repurposed agents for a wide variety of conditions including but not limited to COVID-19, Alzheimer's disease, and neoplastic processes. Further research, particularly randomized controlled trials, will be necessary to confirm the utility of SRIs for new indications.

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.

Antitumor Effect of Fluoxetine on Chronic Stress-Promoted Lung Cancer Growth via Suppressing Kynurenine Pathway and Enhancing Cellular Immunity

Background: Chronic stress promotes cancer growth. Antidepressant fluoxetine (FLX) is usually prescribed for cancer patients with comorbid depression. FLX displays inhibition on cancer cell proliferation, however, the in vivo activity has not been investigated.

Methods: We explored the antitumor effect of FLX in subcutaneous transplanted lung cancer cells in a tumor-bearing mouse model. Fifty-six C57BL/6 mice were randomly divided into group A (blank control), group B (tumor-bearing control), group C (tumor-bearing + FLX), group D (CUMS control), group E (CUMS + FLX), group F (tumor-bearing + CUMS), and group G (tumor-bearing + CUMS + FLX). 5-HT, tryptophane (Trp), kynurenine, IFN-γ, TNF-α, IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-17A levels were measured by ELISA. T helper (Th), cytotoxic T (Tc) and regulatory T cells (Tregs) subtype were measured by flow cytometry. The antitumor effects of FLX were evaluated by tumor weight. The expression of kynurenine pathway related genes TDO, IDO1, IDO2, and apoptosis-related genes caspase1, 3, 4, 5, 7, 12 in tumor tissues were measured by western blotting and qRT-PCR. A549 cells were exposed with FLX (15 μmol/L) and its effect on cell proliferation, migration, and clonal formation were detected. Kynurenine pathway and apoptosis related gene expression were also measured.

Results:In vivo, chronic stress promoted tumor growth in C57BL/6 mice. FLX administration not only significantly reversed chronic unpredictable mild stress (CUMS)-induced reduction of 5-HT and Trp, increment of kynurenine, but increased CD4⁺ Th and CD8⁺ Tc cells, and reduced CD25⁺ FOXP3⁺ Tregs. FLX promoted Th to differentiate into Th1 cells and increased IL-2 and IFN-γ, meanwhile inhibited Th differentiate into Th2 and Th17 cells and decreased the concentrations of IL-4, IL-6, IL-10, and IL-17A. Chronic stress obviously up-regulated IDO1 and IDO2 expression, down-regulated caspase 4, 7, and 12 expression, meanwhile FLX administration reversed this regulation. However, there was no significant change in TDO, caspase 1, 3, 5. Similarly, in vitro, FLX administration significantly inhibited the proliferation, migration, and clonal formation of A549 cells and induced cell apoptosis. FLX administration down-regulated the expression of IDO1, IDO2, and up-regulated caspase 4, 5, and 7.

Conclusion: Fluoxetine administration could inhibit tumor growth. The inhibition might be via suppressing kynurenine pathway and enhancing cellular immunity.

Antidepressants with anti-tumor potential in treating glioblastoma: A narrative review

Glioblastoma multiforme (GBM) is known as the deadliest form of brain tumor. In addition, its high treatment resistance, heterogeneity, and invasiveness make it one of the most challenging tumors. Depression is a common psychological disorder among patients with cancer, especially GBM. Due to the high occurrence rates of depression in GBM patients and the overlap of molecular and cellular mechanisms involved in the pathogenesis of these diseases, finding antidepressants with antitumor effects could be considered as an affordable strategy for the treatment of GBM. Antidepressants exert their antitumor properties through different mechanisms. According to available evidence in this regard, some of them can eliminate the adverse effects resulting from chemo-radiotherapy in several cancers along with their synergistic effects caused by chemotherapy. Therefore, providing comprehensive insight into this issue would guide scientists and physicians in developing further preclinical studies and clinical trials, in order to evaluate antidepressants' antitumor potential. Considering that no narrative review has been recently published on this issue, specifically on these classes of drugs, we present this article with the purpose of describing the antitumor cellular mechanisms of three classes of antidepressants as follows: tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAOIs) in GBM.

Systems Toxicology Approach for Assessing Developmental Neurotoxicity in Larval Zebrafish

Adverse outcomes that result from chemical toxicity are rarely caused by dysregulation of individual proteins; rather, they are often caused by system-level perturbations in networks of molecular events. To fully understand the mechanisms of toxicity, it is necessary to recognize the interactions of molecules, pathways, and biological processes within these networks. The developing brain is a prime example of an extremely complex network, which makes developmental neurotoxicity one of the most challenging areas in toxicology. We have developed a systems toxicology method that uses a computable biological network to represent molecular interactions in the developing brain of zebrafish larvae. The network is curated from scientific literature and describes interactions between biological processes, signaling pathways, and adverse outcomes associated with neurotoxicity. This allows us to identify important signaling hubs, pathway interactions, and emergent adverse outcomes, providing a more complete understanding of neurotoxicity. Here, we describe the construction of a zebrafish developmental neurotoxicity network and its validation by integration with publicly available neurotoxicity-related transcriptomic datasets. Our network analysis identified consistent regulation of tumor suppressors p53 and retinoblastoma 1 (Rb1) as well as the oncogene Krüppel-like factor (Klf8) in response to chemically induced developmental neurotoxicity. The developed network can be used to interpret transcriptomic data in a neurotoxicological context.

Neuro-Signals from Gut Microbiota: Perspectives for Brain Glioma

Glioblastoma (GBM) is the most aggressive form of glioma tumor in adult brain. Among the numerous factors responsible for GBM cell proliferation and invasion, neurotransmitters such as dopamine, serotonin and glutamate can play key roles. Studies performed in mice housed in germ-free (GF) conditions demonstrated the relevance of the gut-brain axis in a number of physiological and pathological conditions. The gut-brain communication is made possible by vagal/nervous and blood/lymphatic routes and pave the way for reciprocal modulation of functions. The gut microbiota produces and consumes a wide range of molecules, including neurotransmitters (dopamine, norepinephrine, serotonin, gamma-aminobutyric acid [GABA], and glutamate) that reach their cellular targets through the bloodstream. Growing evidence in animals suggests that modulation of these neurotransmitters by the microbiota impacts host neurophysiology and behavior, and affects neural cell progenitors and glial cells, along with having effects on tumor cell growth. In this review we propose a new perspective connecting neurotransmitter modulation by gut microbiota to glioma progression.

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.

Serotonin Pathway in Cancer

Serotonin (5-hydroxytryptamine, 5-HT) is a biogenic monoamine produced from the essential amino acid tryptophan. Serotonin's role as a neurotransmitter in the central nervous system and a motility mediator in the gastrointestinal tract has been well defined, and its function in tumorigenesis in various cancers (gliomas, carcinoids, and carcinomas) is being studied. Many studies have shown a potential stimulatory effect of serotonin on cancer cell proliferation, invasion, dissemination, and tumor angiogenesis. Although the underlying mechanism is complex, it is proposed that serotonin levels in the tumor and its interaction with specific receptor subtypes are associated with disease progression. This review article describes serotonin's role in cancer pathogenesis and the utility of the serotonin pathway as a potential therapeutic target in cancer treatment. Octreotide, an inhibitor of serotonin release, is used in well-differentiated neuroendocrine cancers, and the tryptophan hydroxylase (TPH) inhibitor, telotristat, is currently being investigated in clinical trials to treat patients with metastatic neuroendocrine tumors and advanced cholangiocarcinoma. Several in vitro studies have shown the anticancer effect of 5-HT receptor antagonists in various cancers such as prostate cancer, breast cancer, urinary bladder, colorectal cancer, carcinoid, and small-cell lung cancer. More in vivo studies are needed to assess serotonin's role in cancer and its potential use as an anticancer therapeutic target. Serotonin is also being evaluated for its immunoregulatory properties, and studies have shown its potential anti-inflammatory effect. Therefore, it would be of interest to explore the combination of serotonin antagonists with immunotherapy in the future.

Histone deacetylase inhibitor MPT0B291 suppresses Glioma Growth in vitro and in vivo partially through acetylation of p53

Background: Histone deacetylase (HDAC) inhibitors have emerged as a new class of anti-tumor agents for various types of tumors, including glioblastoma.

Methods and results: We found that a novel HDAC inhibitor, MPT0B291, significantly reduced the cell viability and increased cell death of human and rat glioma cell lines, but not in normal astrocytes. We also demonstrated that MPT0B291 suppressed proliferation by inducing G1 phase cell cycle arrest and increased apoptosis in human and rat glioma cell lines by flow cytometry and immunocytochemistry. We further investigated the anti-tumor effects of MPT0B291 in xenograft (mouse) and allograft (rat) models. The IVIS200 images and histological analysis indicated MPT0B291 (25 mg/kg, p. o.) reduced tumor volume. Mechanistically, MPT0B291 increased phosphorylation and acetylation/activation of p53 and increased mRNA levels of the apoptosis related genes PUMA, Bax, and Apaf1 as well as increased protein level of PUMA, Apaf1 in C6 cell line. The expression of cell cycle related gene p21 was also increased and Cdk2, Cdk4 were decreased by MPT0B291.

Conclusion: Our study highlights the anti-tumor efficacy of a novel compound MPT0B291 on glioma growth.

Association between selective serotonin reuptake inhibitors and kidney cancer risk: A nationwide population-based cohort study

The association between selective serotonin reuptake inhibitor (SSRI) exposure and cancer incidence has been investigated; however, no epidemiological study has investigated the association between exposure to individual SSRIs and kidney cancer incidence. The aim of this study is to examine whether SSRI use affected the risk of kidney cancer. We conducted a population-based retrospective cohort study using data from Taiwan's National Health Insurance Research Database. After adjusting for sex, age, urbanization level, comorbidity and medication use through propensity score matching, we identified 222 024 SSRI users and 221 361 SSRI nonusers. A robust Cox proportional hazards model was used to examine the associations between use of individual SSRIs and the risk of kidney cancer with 1- and 2-year induction periods. The result showed that SSRI users tended to be associated with a lower risk of kidney cancer with a 2-year induction period than nonusers; however, the association was not statistically significant (adjusted hazards ratio [aHR] = 0.88, 95% confidence interval [CI] = 0.77-1.01). We further examined the effects of individual SSRIs and observed a significantly lower risk of kidney cancer associated with the use of citalopram (aHR = 0.67, 95% CI = 0.47-0.96) and paroxetine (aHR = 0.75, 95% CI = 0.58-0.97) with the 2-year induction period. These findings support that SSRIs are associated with decreased kidney cancer risk and indicate that citalopram and paroxetine have protective effects in depressed patients with kidney cancer.

Antidepressant drug use in glioblastoma patients: an epidemiological view

Background

Antidepressant drugs have shown antitumor activity in preclinical glioblastoma studies. Antidepressant drug use, as well as its association with survival, in glioblastoma patients has not been well characterized on a population level.

Methods

Patient characteristics, including the frequency of antidepressant drug use, were assessed in a glioblastoma cohort diagnosed in a 10-year time frame between 2005 and 2014 in the Canton of Zurich, Switzerland. Cox proportional hazards regression models were applied for multivariate analysis. Kaplan-Meier survival curves were used to estimate overall survival (OS) data and the log-rank test was performed for comparisons.

Results

A total of 404 patients with isocitrate dehydrogenase wild-type glioblastoma were included in this study. Sixty-five patients (16.1%) took antidepressant drugs at some point during the disease course. Patients were most commonly prescribed selective serotonin reuptake inhibitors at any time (N = 46, 70.8%). Nineteen patients (29.2%) were on antidepressant drugs at the time of their tumor diagnosis. No differences were observed in OS between those patients who had taken antidepressants at some point in their disease course and those who had not (P = .356). These data were confirmed in a multivariate analysis including age, Karnofsky Performance Scale (KPS), sex, extent of resection, O⁶-methylguanine DNA methyltransferase (MGMT) promoter methylation status, and first-line treatment as cofounders (P = .315). Also, there was no association of use of drugs modulating voltage-dependent potassium channels (citalopram; escitalopram) with survival (P = .639).

Conclusions

This signal-seeking study does not support the hypothesis that antidepressants have antitumor efficacy in glioblastoma on a population level.

Effect of Comorbid Depression on Surgical Outcomes After Craniotomy for Malignant Brain Tumors: A Nationwide Readmission Database Analysis

OBJECTIVE

Quality of life is paramount in patients with advanced cancer and may be adversely affected by comorbid depression. We hypothesized that comorbid depression is associated with higher rates of postoperative complications, worse functional outcomes, and higher rates of readmission after craniotomy for resection of malignant intracranial tumors.

METHODS

The National Readmissions Database was queried from 2010 to 2014 to identify adult patients undergoing craniotomy for malignant brain tumor resection. The primary psychiatric disease assessed was major depressive disorder (MDD). Outcomes evaluated included neurologic or other major complications, incidence of nonroutine discharge, and unplanned readmission at 30 and 90 days.

RESULTS

Of the 57,621 craniotomies for malignant neoplasms included in the analysis, 11.32% of patients had clinically diagnosed MDD. The presence of MDD was associated with nonroutine discharge (odds ratio, 1.10-125; P < 0.0001) as well as higher rates of neurologic complications (odds ratio, 1.03-1.18; P = 0.003). No association between MDD and 30-day or 90-day readmissions was noted. Patients with major All Patient Refined Diagnosis Related Groups severity and index length of stay >7 days experienced higher rates of 30-day and 90-day readmissions.

CONCLUSIONS

There is a clinically significant rate of comorbid MDD in patients with malignant intracranial tumors, and MDD is associated with worse perioperative outcomes. Given the wealth of behavioral and pharmaceutical therapies available, MDD is a modifiable risk factor in this cohort that clinicians should be vigilant in screening for and initiating appropriate treatment protocols.

Fluoxetine as an antidepressant medicine improves the effects of ionizing radiation for the treatment of glioma

Radiotherapy is a cancer treatment protocol which delivers high dose of ionizing radiation (IR) to tumor. Tumor resistance and side effects induced by IR still are the major challenges in radiotherapy. The purpose of this study was to evaluate the synergistic killing effect of fluoxetine (FL) with IR on glioma cancer cell (U-87 MG), as well as radioprotective effect of FL against cellular toxicity induced by IR on non-malignant human fibroblast cell (HFFF2). Firstly, the inhibitory effects of FL on cell proliferations were evaluated in U-87 MG and HFFF2 cells. The clonogenic and MTT assays were used to evaluate the radiosensitivity and radioprotective effects of FL on cancer and non-malignant cells. The frequencies of apoptotic cells were evaluated by flow cytometry on both cancer and normal cells. Results showed that FL exhibited anti-cancer effect on glioma cells, while cellular toxicity was low in HFFF2 cells treated with FL. FL decreased the viable colonies and enhanced apoptotic cells when U-87 cells were treated with FL prior irradiation. For comparison, FL exhibited radioprotective effect through increasing cellular proliferation rate and reducing apoptosis in HFFF2 cells against IR. The results showed that FL enhanced the IR-induced glioma cancer cell death and apoptosis, whereas it exhibited a radioprotective effect on normal fibroblast cells suggesting that FL administration may improve glioma radiotherapy.

The Association between Selective Serotonin Reuptake Inhibitors (SSRIs) Use and the Risk of Bladder Cancer: A Nationwide Population-Based Cohort Study

Background: Past studies suggest mixed associations between selective serotonin reuptake inhibitor (SSRI) prescription and carcinogenic risk. There is no epidemiological study reporting on the association between SSRI use and the incidence of bladder cancer. The aim of this study is to determine whether SSRI use influences the risk of bladder cancer. Methods: We conducted a nationwide retrospective cohort study by Taiwan’s National Health Insurance Research Database from January 1, 1997 to December 31, 2013. 192,392 SSRI prescribed individuals were randomly matched 1 to 1 with 191,786 individuals who had never received any SSRIs by propensity scores match. The Cox Proportional Hazard models were conducted to examine the risk of bladder cancer between individuals prescribed SSRIs and individuals not prescribed SSRIs. Results: SSRIs were associated with significant reduced risk of bladder cancer with 0.5, 1, and 2 year induction periods (adjusted hazard ratio (aHR) = 0.86, 95% CI (confidence interval) = 0.76–0.98, aHR = 0.85, 95% CI = 0.75–0.97, and aHR = 0.77, 95% CI = 0.66–0.89). When examining the effect of specific SSRI, there was significantly lower risk of bladder cancer in individuals prescribed fluoxetine (6 month induction period: aHR = 0.78, 95% CI = 0.65–0.93; 1 year induction period: aHR = 0.78, 95% CI = 0.65–0.94; 2 year induction period: aHR = 0.73, 95% CI = 0.60–0.89), paroxetine (6 month induction period: aHR = 0.78, 95% CI = 0.61–0.99; 1 year induction period: aHR = 0.79, 95% CI = 0.61–1.01; 2 year induction period: aHR = 0.72, 95% CI = 0.54–0.95), and citalopram (6 month induction period: aHR = 0.74, 95% CI = 0.53–1.03; 1 year induction period: aHR = 0.70, 95% CI = 0.50–0.99; 2 year induction period: aHR = 0.60, 95% CI = 0.41–0.88). Conclusions: Individuals prescribed fluoxetine, paroxetine, or citalopram had a reduced risk of bladder cancer in this large, cross-national database.

Induction of apoptosis through extrinsic/intrinsic pathways and suppression of ERK/NF-κB signalling participate in anti-glioblastoma of imipramine

Glioblastomas are the most aggressive type of brain tumour, with poor prognosis even after standard treatment such as surgical resection, temozolomide and radiation therapy. The overexpression of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in glioblastomas is recognized as an important treatment target. Thus, an urgent need regarding glioblastomas is the development of a new, suitable agent that may show potential for the inhibition of extracellular signal-regulated kinase (ERK)/NF-κB-mediated glioblastoma progression. Imipramine, a tricyclic antidepressant, has anti-inflammatory actions against inflamed glial cells; additionally, imipramine can induce glioblastoma toxicity via the activation of autophagy. However, whether imipramine can suppress glioblastoma progression via the induction of apoptosis and blockage of ERK/NF-κB signalling remains unclear. The main purpose of this study was to investigate the effects of imipramine on apoptotic signalling and ERK/NF-κB-mediated glioblastoma progression by using cell proliferation (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide [MTT] assay), flow cytometry, Western blotting, and cell invasion/migration assay analysis in vitro. The ERK and NF-κB inhibitory capacity of imipramine is detected by NF-κB reporter gene assay and Western blotting. Additionally, a glioblastoma-bearing animal model was used to validate the therapeutic efficacy and general toxicity of imipramine. Our results demonstrated that imipramine successfully triggered apoptosis through extrinsic/intrinsic pathways and suppressed the invasion/migration ability of glioblastoma cells. Furthermore, imipramine effectively suppressed glioblastoma progression in vivo via the inhibition of the ERK/NF-κB pathway. In summary, imipramine is a potential anti-glioblastoma drug which induces apoptosis and has the capacity to inhibit ERK/NF-κB signalling.

Mechanisms of malignancy in glioblastoma cells are linked to mitochondrial Ca2 + uniporter upregulation and higher intracellular Ca2+ levels

Glioblastoma (GBM) is one of the most malignant brain tumours and, despite advances in treatment modalities, it remains largely incurable. Ca²⁺ regulation and dynamics play crucial roles in different aspects of cancer, but they have never been investigated in detail in GBM. Here, we report that spontaneous Ca²⁺ waves in GBM cells cause unusual intracellular Ca²⁺ ([Ca²⁺]_i) elevations (>1 μM), often propagating through tumour microtubes (TMs) connecting adjacent cells. This unusual [Ca²⁺]_i elevation is not associated with the induction of cell death and is concomitant with overexpression of mitochondrial Ca²⁺ uniporter (MCU). We show that MCU silencing decreases proliferation and alters [Ca²⁺]_i dynamics in U87 GBM cells, while MCU overexpression increases [Ca²⁺]_i elevation in human astrocytes (HAs). These results suggest that changes in the expression level of MCU, a protein involved in intracellular Ca²⁺ regulation, influences GBM cell proliferation, contributing to GBM malignancy.This article has an associated First Person interview with the first author of the paper.

Fluoxetine Simultaneously Induces Both Apoptosis and Autophagy in Human Gastric Adenocarcinoma Cells

Fluoxetine is used widely as an antidepressant for the treatment of cancer-related depression, but has been reported to also have anti-cancer activity. In this study, we investigated the cytotoxicity of fluoxetine to human gastric adenocarcinoma cells; as shown by the MTT assay, fluoxetine induced cell death. Subsequently, cells were treated with 10 or 20 µM fluoxetine for 24 h and analyzed. Apoptosis was confirmed by the increased number of early apoptotic cells, shown by Annexin V- propidium iodide staining. Nuclear condensation was visualized by DAPI staining. A significant increase in the expression of cleaved PARP was observed by western blotting. The pan-caspase inhibitor Z-VAD-FMK was used to detect the extent of caspase-dependent cell death. The induction of autophagy was determined by the formation of acidic vesicular organelles (AVOs), which was visualized by acridine orange staining, and the increased expression of autophagy markers, such as LC3B, Beclin 1, and p62/SQSTM 1, observed by western blotting. The expression of upstream proteins, such as p-Akt and p-mTOR, were decreased. Autophagic degradation was evaluated by using bafilomycin, an inhibitor of late-stage autophagy. Bafilomycin did not significantly enhance LC3B expression induced by fluoxetine, which suggested autophagic degradation was impaired. In addition, the co-administration of the autophagy inhibitor 3-methyladenine and fluoxetine significantly increased fluoxetine-induced apoptosis, with decreased p-Akt and markedly increased death receptor 4 and 5 expression. Our results suggested that fluoxetine simultaneously induced both protective autophagy and apoptosis and that the inhibition of autophagy enhanced fluoxetine-induced apoptosis through increased death receptor expression.

A retrospective survival analysis of Glioblastoma patients treated with selective serotonin reuptake inhibitors

Glioblastoma (GBM) is the most common and aggressive form of malignant glioma in adults with a median overall survival (OS) time of 16-18 months and a median age of diagnosis at 64 years old. Recent work has suggested that depression and psychosocial distress are associated with worse outcomes in patients with GBM. We therefore hypothesized that the targeted neutralization of psychosocial distress with selective serotonin reuptake inhibitor (SSRI) antidepressant treatment would be associated with a longer OS among patients with GBM. To address this hypothesis, we retrospectively studied the association between adjuvant SSRI usage and OS in GBM patients treated by Northwestern Medicine-affiliated providers. The medical records of 497 GBM patients were analyzed after extraction from the Northwestern Medicine Enterprise Data Warehouse. Data were retrospectively studied using a multivariable Cox model with SSRI use defined as a time-dependent variable for estimating the association with OS. Of the 497 patients, 315 individuals died, while 182 were censored due to the loss of follow-up or were alive at the end of our study. Of the 497 patients, 151 had a recorded use of SSRI treatment during the disease course. Unexpectedly, SSRI usage was not associated with an OS effect in both naïve (HR = 0.81, 95% CI = 0.64-1.03) and adjusted time-dependent (HR = 1.26, 95% CI = 0.97-1.63) Cox models. Ultimately, we failed to find an association between SSRI treatment and an improved OS of patients with GBM. Additional work is necessary for understanding the potential therapeutic effects of SSRIs when combined with other treatment approaches, and immunotherapies in particular, for subjects with GBM.

Fluoxetine Induces Apoptotic and Oxidative Neuronal Death Associated with The Influx of Copper Ions in Cultured Neuronal Cells

We examined the effect of fluoxetine, a selective serotonin reuptake inhibitor antidepressant, on neuronal viability in mouse cortical near-pure neuronal cultures. Addition of fluoxetine to the media for 24 hours induced neuronal death in a concentration-dependent manner. To delineate the mechanisms of fluoxetine-induced neuronal death, we investigated the effects of trolox, cycloheximide (CHX), BDNF, z-VAD-FMK, and various metal-chelators on fluoxetine-induced neuronal death. Neuronal death was assessed by MTT assay. The addition of 20 µM fluoxetine to the media for 24 hours induced 60–70% neuronal death, which was associated with the hallmarks of apoptosis, chromatin condensation and DNA laddering. Fluoxetine-induced death was significantly attenuated by CHX, BDNF, or z-VAD-FMK. Treatment with antioxidants, trolox and ascorbate, also markedly attenuated fluoxetine-induced death. Interestingly, some divalent cation chelators (EGTA, Ca-EDTA, and Zn-EDTA) also markedly attenuated the neurotoxicity. Fluoxetine-induced reactive oxygen species (ROS) generation was measured using the fluorescent dye 2′,7′-dichlorofluorescin diacetate. Trolox and bathocuproine disulfonic acid (BCPS), a cell membrane impermeable copper ion chelator, markedly attenuated the ROS production and neuronal death. However, deferoxamine, an iron chelator, did not affect ROS generation or neurotoxicity. We examined the changes in intracellular copper concentration using a copper-selective fluorescent dye, Phen Green FL, which is quenched by free copper ions. Fluoxetine quenched the fluorescence in neuronal cells, and the quenching effect of fluoxetine was reversed by co-treatment with BCPS, however, not by deferoxamine. These findings demonstrate that fluoxetine could induce apoptotic and oxidative neuronal death associated with an influx of copper ions.

Targeting Cancer Lysosomes with Good Old Cationic Amphiphilic Drugs

Being originally discovered as cellular recycling bins, lysosomes are today recognized as versatile signaling organelles that control a wide range of cellular functions that are essential not only for the well-being of normal cells but also for malignant transformation and cancer progression. In addition to their core functions in waste disposal and recycling of macromolecules and energy, lysosomes serve as an indispensable support system for malignant phenotype by promoting cell growth, cytoprotective autophagy, drug resistance, pH homeostasis, invasion, metastasis, and genomic integrity. On the other hand, malignant transformation reduces the stability of lysosomal membranes rendering cancer cells sensitive to lysosome-dependent cell death. Notably, many clinically approved cationic amphiphilic drugs widely used for the treatment of other diseases accumulate in lysosomes, interfere with their cancer-promoting and cancer-supporting functions and destabilize their membranes thereby opening intriguing possibilities for cancer therapy. Here, we review the emerging evidence that supports the supplementation of current cancer therapies with lysosome-targeting cationic amphiphilic drugs.

Apoptotic effect of fluoxetine through the endoplasmic reticulum stress pathway in the human gastric cancer cell line AGS

Gastric cancer is the fourth most common cancer in the world. Fluoxetine (FLX), a selective serotonin reuptake inhibitor, can inhibit the growth of cancer cells by inducing apoptotic cell death through various signaling pathways. This study was aimed to determine the mechanism of apoptotic cell death induced by FLX in AGS cells. MTT assay for cell viability test and colony forming assay was performed for detection of cell proliferation. Western blot analysis was conducted for protein expression. Increased fluorescence intensity and chromatin condensation were observed using DAPI staining. Production of reactive oxygen species (ROS) was measured by DCFDA assay. AGS cell proliferation was remarkedly inhibited by FLX in a dose-dependent manner starting at a concentration of 20 μM. The expression of death receptors was increased, which resulted in elevated expression of activated caspases and cleaved PARP, leading to FLX-induced apoptosis. Moreover, FLX significantly increased production of ROS, and N-acetyl cysteine, which scavenges ROS, attenuated the cytotoxic effects of FLX. In addition, treatment with FLX increased the expression of the endoplasmic reticulum (ER) stress marker, CHOP. P53 protein expression in AGS cells also decreased significantly with FLX treatment. Inhibition of ER stress significantly decreased the expressions of death receptor 5 (DR5), cleaved caspase 3, and cleaved PARP, but not to control levels. FLX-induced apoptosis in AGS involved upregulation of death receptors, ROS generation, and activation of ER stress.

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.

The interplay among psychological distress, the immune system, and brain tumor patient outcomes

A malignant brain tumor diagnosis is often accompanied with intense feelings and can be associated with psychosocial conditions including depression, anxiety, and/or increased distress levels. Previous work has highlighted the impact of uncontrolled psychological distress among brain tumor patients. Given the negative impact of maladaptive psychosocial and biobehavioral factors on normal immune system functions, the question remains as to how psychological conditions potentially affect the brain tumor patient anti-tumor immune response. Since immunotherapy has yet to show efficacy at increasing malignant glioma patient survival in all randomized, phase III clinical trials to-date, this review provides new insights into the potential negative effects of chronic distress on brain tumor patient immune functions and outcomes.

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.

Antidepressant use in patients with meningioma: is there an association with tumor recurrence?

OBJECTIVE

With increasing general use of antidepressants (ADs), multiple studies have noted a small protective effect of ADs for patients with glioma, but their impact on meningioma has not been established. This study aims to evaluate the role of ADs in the context of additional clinical factors in relation to long-term risk of meningioma recurrence.

METHODS

One hundred five patients with an intracranial meningioma presenting from 2011–2014 with at least 3 years of follow-up (median 4.2 years) after resection were reviewed. AD use along with demographics, tumor characteristics, and outcomes were recorded. Multivariate logistic regression was used to analyze the association of AD use with tumor recurrence, including other clinical measures significantly associated with recurrence as covariates.

RESULTS

Twenty-nine patients (27.4%) were taking ADs (27 selective serotonin reuptake inhibitors, 2 norepinephrine-dopamine reuptake inhibitors) prior to tumor recurrence. Their tumors largely affected the frontal (31.0%) or parietal lobe (17.2%) and were located in convexity, parasagittal, or falcine (CPF) areas more frequently than skull base areas relative to the tumors of non-AD users (p = 0.035). AD use was found to be an independent predictor of recurrence, in addition to subtotal resection and WHO grade II/III classification (p values < 0.05). The median time from AD prescription to tumor recurrence was 36.6 months (interquartile range [IQR] = 20.9–62.9 months) and median length of AD use was 41.4 months (IQR = 24.7–62.8 months).

CONCLUSIONS

AD use was an independent predictor of meningioma recurrence. This association may be due to mood or affective changes caused by tumor location in CPF regions that may be a sign of early recurrence. The finding calls attention to AD use in the management of patients with meningioma, and warrants further exploration of an underlying relationship.

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.

VDAC1 as Pharmacological Target in Cancer and Neurodegeneration: Focus on Its Role in Apoptosis

Cancer and neurodegeneration are different classes of diseases that share the involvement of mitochondria in their pathogenesis. Whereas the high glycolytic rate (the so-called Warburg metabolism) and the suppression of apoptosis are key elements for the establishment and maintenance of cancer cells, mitochondrial dysfunction and increased cell death mark neurodegeneration. As a main actor in the regulation of cell metabolism and apoptosis, VDAC may represent the common point between these two broad families of pathologies. Located in the outer mitochondrial membrane, VDAC forms channels that control the flux of ions and metabolites across the mitochondrion thus mediating the organelle's cross-talk with the rest of the cell. Furthermore, the interaction with both pro-apoptotic and anti-apoptotic factors makes VDAC a gatekeeper for mitochondria-mediated cell death and survival signaling pathways. Unfortunately, the lack of an evident druggability of this protein, since it has no defined binding or active sites, makes the quest for VDAC interacting molecules a difficult tale. Pharmacologically active molecules of different classes have been proposed to hit cancer and neurodegeneration. In this work, we provide an exhaustive and detailed survey of all the molecules, peptides, and microRNAs that exploit VDAC in the treatment of the two examined classes of pathologies. The mechanism of action and the potential or effectiveness of each compound are discussed.

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.

Medication use and kidney cancer survival: A population-based study

Several studies demonstrate that use of commonly prescribed medications is associated with improved survival in various malignancies. Methods of classifying medication use in many of these studies, however, do not account for intermittent or cumulative use. Moreover, there are limited data in kidney cancer. Therefore, we performed a population-based cohort study utilizing healthcare databases in Ontario, Canada. We identified patients aged ≥65 with an incident diagnosis of kidney cancer between 1997 and 2013 and examined use of nine putative anti-neoplastic medications using prescription claims. Cox proportional hazard models evaluated the association of medication exposure on cancer-specific and overall survival. We conducted three separate analyses: the effect of cumulative duration of exposure to the study medications on outcomes, the effect of current exposure (in a binary nature) and the effect of exposure at diagnosis. During the 16-year study period, we studied 9,124 patients. Increasing cumulative use of angiotensin-converting enzyme inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs) and selective serotonin reuptake inhibitors were associated with markedly improved cancer-specific survival; increasing use of NSAIDs was associated with markedly improved overall survival. These results were generally discordant with analyses evaluating the effect of current use and exposure at diagnosis. In conclusion, pharmacoepidemiology studies may be sensitive to the method of analysis; cumulative use analyses may be the most robust as it accounts for intermittent use and supports a dose-outcome relationship. Prospective studies are needed to confirm whether patients diagnosed with kidney cancer should be started on an angiotensin-converting enzyme inhibitor, NSAID or selective serotonin reuptake inhibitor to improve survival.

Antidepressants, sertraline and paroxetine, increase calcium influx and induce mitochondrial damage-mediated apoptosis of astrocytes

The impacts of antidepressants on the pathogenesis of dementia remain unclear despite depression and dementia are closely related. Antidepressants have been reported may impair serotonin-regulated adaptive processes, increase neurological side-effects and cytotoxicity. An ‘astroglio-centric’ perspective of neurodegenerative diseases proposes astrocyte dysfunction is involved in the impairment of proper central nervous system functioning. Thus, defining whether antidepressants are harmful to astrocytes is an intriguing issue. We used an astrocyte cell line, primary cultured astrocytes and neuron cells, to identify the effects of 11 antidepressants which included selective serotonin reuptake inhibitors, a serotonin-norepinephrine reuptake inhibitor, tricyclic antidepressants, a tetracyclic antidepressant, a monoamine oxide inhibitor, and a serotonin antagonist and reuptake inhibitor. We found that treatment with 10 μM sertraline and 20 μM paroxetine significantly reduced cell viability. We further explored the underlying mechanisms and found induction of the [Ca²⁺]_i level in astrocytes. We also revealed that sertraline and paroxetine induced mitochondrial damage, ROS generation, and astrocyte apoptosis with elevation of cleaved-caspase 3 and cleaved-PARP levels. Ultimately, we validated these mechanisms in primary cultured astrocytes and neuron cells and obtained consistent results. These results suggest that sertraline and paroxetine cause astrocyte dysfunction, and this impairment may be involved in the pathogenesis of neurodegenerative diseases.

Escitalopram oxalate induces apoptosis in U-87MG cells and autophagy in GBM8401 cells

Glioblastoma multiforme (GBM) is recognized as a most aggressive brain cancer with the worst prognosis and survival time. Owing to the anatomic location of gliomas, surgically removing the tumour is very difficult and avoiding damage to vital brain regions during radiotherapy is impossible. Therefore, therapeutic strategies for malignant glioma must urgently be improved. Recent studies have demonstrated that selective serotonin reuptake inhibitors (SSRIs) have cytotoxic effect on certain cancers. Considering as a more superior SSRI, escitalopram oxalate exhibits favourable tolerability and causes generally mild and temporary adverse events. However, limited information is revealed about the influence of escitalopram oxalate on GBM. Therefore, an attempt was made herein to explore the effects of escitalopram oxalate on GBM. The experimental results revealed that escitalopram oxalate significantly inhibits the proliferation and invasive ability of U‐87MG cells and significantly reduced the expressions of cell cycle inhibitors such as Skp2, P57, P21 and P27. Notably, escitalopram oxalate also induced significant apoptotic cascades in U‐87MG cells and autophagy in GBM8401 cells. An animal study indicated that escitalopram oxalate inhibits the proliferation of xenografted glioblastoma in BALB/c nude mice. These findings implied that escitalopram oxalate may have potential in treatment of glioblastomas.

The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload

Selective Serotonin Reuptake Inhibitor antidepressants, such as fluoxetine (Prozac), have been shown to induce cell death in cancer cells, paving the way for their potential use as cancer therapy. These compounds are able to increase cytosolic calcium concentration ([Ca2+]cyt), but the involved mechanisms and their physiological consequences are still not well understood. Here, we show that fluoxetine induces an increase in [Ca2+]cyt by emptying the endoplasmic reticulum (ER) through the translocon, an ER Ca2+ leakage structure. Our data also show that fluoxetine inhibits oxygen consumption and lowers mitochondrial ATP. This latter is essential for Ca2+ reuptake into the ER, and we postulated therefore that the fluoxetine-induced decrease in mitochondrial ATP production results in the emptying of the ER, leading to capacitative calcium entry. Furthermore, Ca2+ quickly accumulated in the mitochondria, leading to mitochondrial Ca2+ overload and cell death. We found that fluoxetine could induce an early necrosis in human peripheral blood lymphocytes and Jurkat cells, and could also induce late apoptosis, especially in the tumor cell line. These results shed light on fluoxetine-induced cell death and its potential use in cancer treatment.