The cell death response to gamma-radiation in MCF-7 cells is enhanced by a neuroleptic drug, pimozide

The antipsychotic drug pimozide promotes apoptosis through the RAF/ERK pathway and enhances autophagy in breast cancer cells

The antipsychotic drug pimozide has been demonstrated to inhibit cancer. However, the precise anti-cancer mechanism of pimozide remains unclear. The purpose of this study was to investigate the effects of pimozide on human MCF-7 and MDA-MB-231 breast cancer cell lines, and the potential involvement in the RAF/ERK signaling. The effects of pimozide on cells were examined by 4,5-dimethylthiazol-2-yl-3,5-diphenylformazan, wound healing, colony formation, transwell assays, and caspase activity assay. Flow cytometry and acridine orange and ethidium bromide staining were performed to assess changes in cells. Transmission electron microscopy and monodansylcadaverine staining were used to observe autophagosomes. The cyclic adenosine monophosphate was evaluated using the FRET system. Immunohistochemistry, immunofluorescence, RNA interference, and western blot investigated the expression of proteins. Mechanistically, we focus on the RAF1/ERK signaling. We detected pimozide was docked to RAF1 by Schrodinger software. Pimozide down-regulated the phosphorylation of RAF1, ERK 1/2, Bcl-2, and Bcl-xl, up-regulated Bax, and cleaved caspase-9 to induce apoptosis. Pimozide might promote autophagy by up-regulating cAMP. The enhancement of autophagy increased the conversion of LC3-I to LC3-II and down-regulated p62 expression. But mTOR signaling was not involved in promoting autophagy. The knockdown of RAF1 expression induced autophagy and apoptosis in breast cancer cells, consistent with the results of pimozide or sorafenib alone. Blocked autophagy by chloroquine resulted in the impairment of pimozide-induced apoptosis. These data showed that pimozide inhibits breast cancer by regulating the RAF/ERK signaling pathway and might activate cAMP-induced autophagy to promote apoptosis and it may be a potential drug for breast cancer treatment.

Role of autophagy in modulating tumor cell radiosensitivity: Exploring pharmacological interventions for glioblastoma multiforme treatment

Autophagy is an innate cellular process characterized by self-digestion, wherein cells degrade or recycle aged proteins, misfolded proteins, and damaged organelles via lysosomal pathways. Its crucial role in maintaining cellular homeostasis, ensuring development and survival is well established. In the context of cancer therapy, autophagy's importance is firmly recognized, given its critical impact on treatment efficacy. Following radiotherapy, several factors can modulate autophagy including parameters related to radiation type and delivery methods. The concomitant use of chemotherapy with radiotherapy further influences autophagy, potentially either enhancing radiosensitivity or promoting radioresistance. This review article discusses some pharmacological agents and drugs capable of modulating autophagy levels in conjunction with radiation in tumor cells, with a focus on those identified as potential radiosensitizers in glioblastoma multiforme treatment.

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

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

Multi-targeted drug repurposing approach for breast cancer via integrated functional network analysis

The present study focuses on the interconnected functional network of altered metabolism and EMT (epithelial to mesenchymal transition) signaling in breast cancer. We have interlinked the metabolic and EMT signaling circuits and selected Insulin receptor (IR), Integrin beta 1 (ITGB1), and CD36 as target proteins based on network analysis. Extensive computational approaches discerned the potential drug molecules from the library of 1293 FDA-approved drugs to block all three target proteins. Using molecular docking, molecular dynamics simulation, and MMPBSA binding free energy studies, Capmatinib, Ponatinib, Naldemedine, and Pimozide were identified as potential repurposed drugs to block the function of all three target proteins. Among in silico selected candidate drugs, Pimozide, a known anti-psychotic drug, was further validated using in-vitro studies for its anti-cell proliferative potential on breast cancer cell lines (namely, MCF7, MDAMB231 and MDAMB468). The inhibitory concentration (IC50) values of MCF7, MDAMB231 and MDAMB468 was found to be 16.26 µM, 20.82 µM and 13.10 µM, respectively. The effect of Pimozide on EMT-induced MDAMB231 and MDAMB468 cells was evident from their IC50 values of 7.85 µM and 6.83 µM, respectively. The potent anti-cancer property of Pimozide has opened up avenues for drug repurposing towards 'multi-targeted therapy' in EMT dynamics.

Antidepressants and Antipsychotic Agents as Repurposable Oncological Drug Candidates

Drug repurposing, also known as drug repositioning/reprofiling, is a relatively new strategy for the identification of alternative uses of well-known therapeutics that are outside the scope of their original medical indications. Such an approach might entail a number of advantages compared to standard de novo drug development, including less time needed to introduce the drug to the market, and lower costs. The group of compounds that could be considered as promising candidates for repurposing in oncology include the central nervous system drugs, especially selected antidepressant and antipsychotic agents. In this article, we provide an overview of some antidepressants (citalopram, fluoxetine, paroxetine, sertraline) and antipsychotics (chlorpromazine, pimozide, thioridazine, trifluoperazine) that have the potential to be repurposed as novel chemotherapeutics in cancer treatment, as they have been found to exhibit preventive and/or therapeutic action in cancer patients. Nevertheless, although drug repurposing seems to be an attractive strategy to search for oncological drugs, we would like to clearly indicate that it should not replace the search for new lead structures, but only complement de novo drug development.

Effect of antipsychotics on breast tumors by analysis of the Japanese Adverse Drug Event Report database and cell-based experiments

Background

Since antipsychotics induce hyperprolactinemia via the dopamine D₂ receptor, long-term administration may be a risk factor for developing breast tumors, including breast cancer. On the other hand, some antipsychotic drugs have been reported to suppress the growth of breast cancer cells in vitro. Thus, it is not clear whether the use of antipsychotics actually increases the risk of developing or exacerbating breast tumors. The purpose of this study was to clarify the effects of antipsychotic drugs on the onset and progression of breast tumors by analyzing an adverse event spontaneous reporting database and evaluating the proliferation ability of breast cancer cells.

Methods

Japanese Adverse Drug Event Report database (JADER) reports from April 2004 to April 2019 were obtained from the Pharmaceuticals and Medical Devices Agency (PMDA) website. Reports of females only were analyzed. Adverse events included in the analysis were hyperprolactinemia and 60 breast tumor-related preferred terms. The reporting odds ratio (ROR), proportional reporting ratio (PRR), and information component (IC) were used to detect signals. Furthermore, MCF-7 cells were treated with haloperidol, risperidone, paliperidone, sulpiride, olanzapine and blonanserin, and cell proliferation was evaluated by WST-8 assay.

Results

In the JADER analysis, the IC signals of hyperprolactinemia were detected with sulpiride (IC, 3.73; 95% CI: 1.81–5.65), risperidone (IC, 3.69; 95% CI: 1.71–5.61), and paliperidone (IC, 4.54; 95% CI: 2.96–6.12). However, the IC signal of breast tumors was not observed with any antipsychotics. In cell-based experiments, MCF-7 cells were treated with six antipsychotics at concentrations of 2 and 32 μM, and none of the drugs showed any growth-promoting effects on MCF-7 cells. On the other hand, blonanserin markedly suppressed the growth of MCF-7 cells at a concentration of 32 μM, and the effect was concentration dependent.

Conclusions

Analysis of the JADER using the IC did not show breast tumor signals due to antipsychotic drugs. In in vitro experiments, antipsychotics did not promote MCF-7 cell proliferation whereas blonanserin suppressed MCF-7 cell growth. Further research on the effects of blonanserin on the onset and progression of breast tumor is expected.

Repurposing antipsychotics of the diphenylbutylpiperidine class for cancer therapy

The recent development of high throughput compound screening has allowed drug repurposing to emerge as an effective avenue for discovering novel treatments for cancer. FDA-approved antipsychotic drugs fluspirilene, penfluridol, and pimozide are clinically used for the treatment of psychotic disorders, primarily schizophrenia. These compounds, belong to diphenylbutylpiperidine class of antipsychotic drugs, are the potent inhibitors of dopamine D2 receptor and calcium channel. A correlation has been found that patients treated for schizophrenia have lower incidences of certain types of cancer, such as respiratory, prostate, and bladder cancers. These compounds have also been shown to inhibit cancer proliferation in a variety of cancer cells, including melanoma, lung carcinoma, breast cancer, pancreatic cancer, glioma, and prostate cancer, among others. Antipsychotic drugs induce apoptosis and suppress metastasis in in vitro and in vivo models through mechanisms involving p53, STAT3, STAT5, protein phosphatase 2A, cholesterol homeostasis, integrins, autophagy, USP1, wnt/β-catenin signaling, and DNA repair. Additionally, pre-clinical evidence suggests that penfluridol and pimozide act synergistically with existing chemotherapeutic agents, such as dasatinib, temozolomide, and cisplatin. Some studies have also reported that the cytotoxic activity of the antipsychotics is selective for dividing cells. Based on this growing body of evidence and the availability and previous FDA-approval of the drugs, the compounds appear to be promising anti-cancer agents.

Antipsychotic agent pimozide promotes reversible proliferative suppression by inducing cellular quiescence in liver cancer

The antipsychotic drug pimozide has been found to exhibit anticancer effects. Previously, it was demonstrated that pimozide inhibits hepatocellular carcinoma (HCC) cell growth, but its pharmacodynamic characteristics remain unclear. The aim of the present study was to investigate the reversibility and mechanism of the ability of pimozide to inhibit cell proliferation in liver cancer. Cell viability was determined by Cell Counting Kit‑8 and colony formation assay. The cell cycle distribution was analyzed by flow cytometry with Ki‑67 and PI staining. ROS production of HCC cells was detected with DCFH‑DA and inhibited with NAC treatment. Western blot assay was performed to detect the expression of related signaling molecules in HCC cells. Our results showed that pimozide promoted G0/G1 phase arrest in HCC cell lines without significant cell death. Its anti‑proliferative effects on HCC cells were reversible, consistent with involvement of cell quiescence and reactive oxygen species (ROS) production. Pimozide enhanced inhibition of HCC cell proliferation by sorafenib. In conclusion, elucidation of pimozide's reversible proliferation inhibition in liver cancer and additive activity with a well‑established anticancer drug warrants further exploration of the potential of pimozide as an adjuvant anticancer therapy.

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.

Molecular mechanisms of anti-psychotic drugs for improvement of cancer treatment

Anti-psychotic medications are widely used to treat schizophrenia and bipolar disorder. Besides their medical applications, anti-psychotic drugs have other pharmacological properties which are involved in multiple intracellular functions including metabolism, cell stress, cell-cycle regulation, survival and apoptosis through modulation of cellular signaling pathways such as PI3K/Akt/GSK-3β, STAT3 and wingless (Wnt)-related intracellular signaling. Also, anti-psychotics counteract the growth of tumor cells by stimulating the cellular immune system and natural killer cells. On the other hand, the positive charge and the lipophilicity of anti-psychotics have significant roles in the inhibition of P-gp pumps resulting in accumulation of chemotherapy drugs as well as increasing the cellular susceptibility to chemotherapy, autophagy, angiogenesis inhibition, stem cells differentiation induction and changing the expression of tumor suppressor genes and oncogenes. Overall, anti-psychotics are able to inhibit the proliferation of cancer cells through modulation of different cellular pathways. Anti-psychotics act as anti-cancer drugs and besides can increase the efficacy of anti-cancer agents in cancer cells. In this study, the anti-cancer effects of different anti-psychotic medicines on various malignant tumor cells and their molecular mechanisms have been discussed.

Inhibition of cancer stem cells promoted by Pimozide

Over the past years, studies have described that users of antipsychotics are less likely to develop cancer than the population in general due to cytotoxic properties of this class of drugs on cancer cells. For this reason, Pimozide has been widely studied as a potential anticancer treatment, and satisfactory results in melanoma, central nervous system tumours, osteosarcoma, neuroblastoma, myeloproliferative neoplasms, breast, lung, prostate, ovarian, colorectal, pancreatic, and hepatocellular carcinoma have been showed. Moreover, advantages as clinical use approved by the Food and Drug Administration (FDA), high clinical safety, low side effects, and reasonable price have stimulated the treatment with Pimozide instead of other agents. The action mechanism remains unclear, but three vias associated to cancer stem cell (CSC) hypothesis show that Pimozide: (a) blocks CSC features, as epithelial-to-mesenchymal transition (EMT), through inhibition of Wnt-β/catenin signalling; (b) acts as an inhibitor of signal transducer and activator of transcription (STAT-3 and 5), pathway which is activated and up-regulated in CSCs; (c) inhibits ubiquitine specific protease (USP1) and WD repeat-containing protein 48 (WDR48), that are proteins responsible to inhibit the differentiation and to maintain the cell in an undifferentiated state. Based on this perspective, the aim of this manuscript is to review the antineoplastic role of Pimozide during tumorigenesis and its potential to revert the process of undifferentiation and proliferation of CSC through different vias.

The nervous system: a new target in the fight against cancer

During cancer progression, tumor cells interact with the neighboring environment, including neuronal tissue. The important influence of the nervous system on growth and metastasis of cancer is now widely accepted. As such, using medications that traditionally target the nervous system may be an avenue toward treating cancer. The focus of this review is to detail how several classes of medications, traditionally used to treat nervous system disorders, impact cancer. Specifically, we review the preclinical and clinical evidence that support the use of anti-β-adrenergic, anticholinergic, antipsychotic, and antidepressant medications to treat some cancers. In addition, we discuss the use of ablative modalities, such as physical and chemical denervation, to treat cancer or protect against cancer development. Using the medications that target the nervous system to treat cancer is a promising addition to an existing therapy or an alternative treatment strategy. Furthermore, rapidly expanding basic science research in this area will likely yield novel cancer therapies that work by targeting the nervous system.

Study on the role of transient receptor potential C6 channels in esophageal squamous cell carcinoma radiosensitivity

Background

To study the effect of transient receptor potential C6 (TRPC6) channels on esophageal squamous cell carcinoma (ESCC) cell lines Eca109 cell cycle and to confirm whether TRPC6 channel is candidate radiosensitivity in vitro and in vivo.

Methods

We chose Eca109 cell line with a strong TRPC6 channels expression. Cell cycle was investigated after TRPC6 channel inhibitor SKF96365 treated with a 5 µM concentration. According to the results of cell cycle, radiation was performed. CCK-8 test was used to test the cell proliferation. Then we performed the same study in vivo. Total of 40 male nude mice were randomly divided into four groups as follows: SKF96365, radio, combined radio-SKF96365 and control. In SKF96365 group, 20 mg/kg 5 µM SKF96365 was injected into the abdominal cavity of the nude mice at day 5-11. In radiation group, the nude mice received radiotherapy 2 Gy per day at day 7-11. In combined radio-SKF96365 group, 20 mg/kg 5 µM SKF96365 was injected into the abdominal cavity of the nude mice at day 5-11 and 2 Gy radiotherapy was delivered to the tumor site at day 7-11. In control group, nude mice were injected saline into the abdominal cavity at day 5-11. General states of health were observed, the tumor size in volume was measured with calipers two times every week. Six weeks after seeding, mice were sacrificed by neck-break. The tumor size was measured in volume with caliper and in weigh with scale.

Results

Treatment with SKF96365 substantially increased the percentage of Eca109 cells in the G2/M phase and reduced that in G0/G1 phase in a time-dependent manner. Most of the cells (85.26%), 24 h after SKF96365 treatment were arrested in the G2/M phase. CCK-8 test showed that Eca109 ESCC cells received both SKF96365 and radiation showed the worst ability of cell proliferation. The same result was obtained in vivo. Nude mice received combined radio-SKF96365 showed the smallest tumor size and volume.

Conclusions

TRPC6 plays an important role in development of esophageal cancer, and SKF96365 may increase the sensitivity of radiotherapy. TRPC6 may become a new radiotherapy target in esophageal cancer.

The neuroleptic drug pimozide inhibits stem-like cell maintenance and tumorigenicity in hepatocellular carcinoma

Drug repurposing is currently an important approach for accelerating drug discovery and development for clinical use. Hepatocellular carcinoma (HCC) presents drug resistance to chemotherapy, and the prognosis is poor due to the existence of liver cancer stem-like cells. In this study, we investigated the effect of the neuroleptic agent pimozide to inhibit stem-like cell maintenance and tumorigenicity in HCC. Our results showed that pimozide functioned as an anti-cancer drug in HCC cells or stem-like cells. Pimozide inhibited cell proliferation and sphere formation capacities in HCC cells by inducing G0/G1 phase cell cycle arrest, as well as inhibited HCC cell migration. Surprisingly, pimozide inhibited the maintenance and tumorigenicity of HCC stem-like cells, particularly the side population (SP) or CD133-positive cells, as evaluated by colony formation, sphere formation and transwell migration assays. Furthermore, pimozide was found to suppress STAT3 activity in HCC cells by attenuating STAT3-dependent luciferase activity and down-regulating the transcription levels of downstream genes of STAT3 signaling. Moreover, pimozide reversed the stem-like cell tumorigenic phenotypes induced by IL-6 treatment in HCC cells. Further, the antitumor effect of pimozide was also proved in the nude mice HCC xenograft model. In short, the anti-psychotic agent pimozide may act as a novel potential anti-tumor agent in treating advanced HCC.

Repurposing antipsychotics as glioblastoma therapeutics: Potentials and challenges

Glioblastoma multiforme (GBM) is the most common and most lethal primary brain tumor, with tragically little therapeutic progress over the last 30 years. Surgery provides a modest benefit, and GBM cells are resistant to radiation and chemotherapy. Despite significant development of the molecularly targeting strategies, the clinical outcome of GBM patients remains dismal. The challenges inherent in developing effective GBM treatments have become increasingly clear, and include resistance to standard treatments, the blood-brain barrier, resistance of GBM stem-like cells, and the genetic complexity and molecular adaptability of GBM. Recent studies have collectively suggested that certain antipsychotics harbor antitumor effects and have potential utilities as anti-GBM therapeutics. In the present review, the anti-tumorigenic effects and putative mechanisms of antipsychotics, and the challenges for the potential use of antipsychotic drugs as anti-GBM therapeutics are reviewed.

Inhibition of T-type Ca²⁺ channels by endostatin attenuates human glioblastoma cell proliferation and migration

BACKGROUND AND PURPOSE

Endostatin (ES) is a c-terminal proteolytic fragment of collagen XVIII with promising antitumour properties in several tumour models, including human glioblastoma. We hypothesized that this peptide could interact with plasma membrane ion channels and modulate their functions.

EXPERIMENTAL APPROACH

Using cell proliferation and migration assays, patch clamp and Western blot analysis, we studied the effects of ES on the proliferation and migration of human glioblastoma U87 cells, mediated by T-type Ca²⁺ channels.

KEY RESULTS

Extracellular application of ES reversibly inhibited T-type Ca²⁺ channel currents (T-currents) in U87 cells, whereas L-type Ca²⁺ currents were not affected. This inhibitory effect was associated with a hyperpolarizing shift in the voltage-dependence of inactivation but was independent of G-protein and protein tyrosine kinase-mediated pathways. All three α₁ subunits of T-type Ca²⁺ channels (Ca(V) 3), α(1G) (Ca(V) 3.1), α(1H) (Ca(V) 3.2) and α(1I) (Ca(V) 3.3), were endogenously expressed in U87 cells. Using transfected HEK293 or CHO cells, we showed that only Ca(V) 3.1 and Ca(V) 3.2, but not Ca(V) 3.3 or Ca(V) 1.2 (L-type), channel currents were significantly inhibited. More interestingly, ES inhibited the proliferation and migration of U87 cells in a dose-dependent manner. Pretreatment of the cells with the specific T-type Ca²⁺ channel blocker mibefradil occluded these inhibitory effects of ES.

CONCLUSION AND IMPLICATIONS

This study provides the first evidence that the antitumour effects of ES on glioblastoma cells is through direct inhibition of T-type Ca²⁺ channels and gives new insights into the future development of a new class of antiglioblastoma agents that target the proliferation and migration of these cells.

Integrating constitutive gene expression and chemoactivity: mining the NCI60 anticancer screen

Studies into the genetic origins of tumor cell chemoactivity pose significant challenges to bioinformatic mining efforts. Connections between measures of gene expression and chemoactivity have the potential to identify clinical biomarkers of compound response, cellular pathways important to efficacy and potential toxicities; all vital to anticancer drug development. An investigation has been conducted that jointly explores tumor-cell constitutive NCI60 gene expression profiles and small-molecule NCI60 growth inhibition chemoactivity profiles, viewed from novel applications of self-organizing maps (SOMs) and pathway-centric analyses of gene expressions, to identify subsets of over- and under-expressed pathway genes that discriminate chemo-sensitive and chemo-insensitive tumor cell types. Linear Discriminant Analysis (LDA) is used to quantify the accuracy of discriminating genes to predict tumor cell chemoactivity. LDA results find 15% higher prediction accuracies, using ∼30% fewer genes, for pathway-derived discriminating genes when compared to genes derived using conventional gene expression-chemoactivity correlations. The proposed pathway-centric data mining procedure was used to derive discriminating genes for ten well-known compounds. Discriminating genes were further evaluated using gene set enrichment analysis (GSEA) to reveal a cellular genetic landscape, comprised of small numbers of key over and under expressed on- and off-target pathway genes, as important for a compound’s tumor cell chemoactivity. Literature-based validations are provided as support for chemo-important pathways derived from this procedure. Qualitatively similar results are found when using gene expression measurements derived from different microarray platforms. The data used in this analysis is available at http://pubchem.ncbi.nlm.nih.gov/andhttp://www.ncbi.nlm.nih.gov/projects/geo (GPL96, GSE32474).

Antipsychotic drugs: pro-cancer or anti-cancer? A systematic review

INTRODUCTION

Important data was recently published on the potential genotoxic or carcinogenic effects of antipsychotics, as well as on their cytotoxic properties on cancer cells, that must be considered by psychiatrists in the benefit/risk ratio of their prescriptions.

AIM OF THE STUDY

To answer whether or not antipsychotics, as a class or only some specific molecules, may influence cancer risk among treated patients. METHODS ELIGIBILITY CRITERIA: All studies (in vitro, animal studies and human studies) concerning effects of antipsychotic drugs on cancer development were included. The search paradigm [neoplasms AND (antipsychotic agents OR neuroleptic OR phenothiazine)] was applied to Medline (1966-present) and Web of Science (1975-present).

RESULTS

Ninety-three studies were included in the qualitative synthesis. Results can be summarized as follows: (1) patients with schizophrenia may be less likely to develop cancer than the general population, (2) antipsychotics as a class cannot be considered at the moment as at risk for cancer, even if some antipsychotics have shown carcinogenic properties among rodents, (3) phenothiazines seem to have antiproliferative properties that may be useful in multidrug augmentation strategies in various cancer treatments, but their bad tolerance may decrease usage amongst non-psychotic patients, and (4) clozapine appears to have a separate status given that this molecule shows antiproliferative effects implied in agranulocytosis as well as a potential increased risk for leukemia.

CONCLUSION

Benefit/risk ratio regarding cancer risk is in favor of treating patients with schizophrenia with antipsychotic drugs. The practicing clinician should be reassuring on the subject of cancer risk due to antipsychotic drugs.

Cytotoxic effects of antipsychotic drugs implicate cholesterol homeostasis as a novel chemotherapeutic target

The reported reduction in cancer risk in those suffering from schizophrenia may be because antipsychotic medications have antineoplastic effects. In this study, 6 antipsychotic agents with a range of structural and pharmacological properties (reserpine, chlorpromazine, haloperidol, pimozide, risperidone and olanzapine), were screened for their effect on the viability of cell lines derived from lymphoblastoma, neuroblastoma, non-small cell lung cancer and breast adenocarcinoma. We aimed to determine if antipsychotic drugs in general possess cancer-specific cytotoxic potential, and whether it can be attributed to a common mode of action. With the exception of risperidone, all drugs tested displayed selective inhibition of the viability of cancer cell lines compared with normal cells. Using Affymetrix expression microarrays and quantitative real-time polymerase chain reaction, we found that for the antipsychotic drugs, olanzapine and pimozide, cytotoxicity appeared to be mediated via effects on cholesterol homeostasis. The role of cholesterol metabolism in the selective cytotoxicity of these drugs was supported by demonstration of their increased lethality when coadministered with a cholesterol synthesis inhibitor, mevastatin. Also, pimozide and olanzapine showed accelerating cytotoxic effects from 12 to 48 hr in time course studies, mirroring the time-dependent onset of cytotoxicity induced by the amphiphile, U18666A. On the basis of these results, we concluded that the Class II cationic amphiphilic properties of antipsychotic drugs contribute to their cytotoxic effects by acting on cholesterol homeostasis and altering the biophysical properties of cellular membranes, and that drugs affecting membrane-related cholesterol pathways warrant further investigation as potential augmentors of standard cancer chemotherapy.

Hydroxychloroquine, chloroquine, and all-trans retinoic acid regulate growth, survival, and histone acetylation in breast cancer cells

The antimalarial drugs chloroquine (CQ) and hydroxychloroquine (HCQ) have potential applications in cancer treatment. The growth of MCF-7 and MDA-MB-231 human breast cancer cells in vitro was inhibited by CQ and HCQ and these cells were more sensitive than nontumorigenic MCF-10A breast epithelial cells. Furthermore, all-trans retinoic acid (ATRA) augmented the anticancer effects of CQ and HCQ as evidenced by significant reductions in Ki67-positive cancer cells and clonogenicity compared with cells treated with CQ or HCQ in the absence of ATRA. As an earlier study suggested that CQ, HCQ, and ATRA are breast cancer cell differentiation agents, these agents were screened in cell-free histone deacetylase (HDAC) and histone acetyltransferase (HAT) assays. ATRA, but not CQ or HCQ, inhibited HDAC activity in HeLa nuclear extracts. Growth inhibitory concentrations of HCQ and ATRA stimulated purified p300/CBP-associated factor, where CBP is the cAMP-response element binding protein, HAT activity. To investigate whether growth inhibitory concentrations of these agents influenced protein acetylation in cells, gel-purified histone H3 and histone H4 were analyzed using mass spectrometry. HCQ alone and HCQ+ATRA treatments altered the acetylation status in the N-terminal lysines of histones H3 and H4 compared with dimethyl sulfoxide (DMSO) controls. The results indicated that HCQ and ATRA regulate protein acetylation events in MCF-7 breast cancer cells, and identify a potential mechanism for their effects on breast cancer cell growth and differentiation.

T-type Ca2+ channel blockers suppress the growth of human cancer cells

In order to further clarify the role of T-type Ca(2+) channels in cell proliferation, we have measured the growth inhibition of human cancer cells by using our potent T-type Ca(2+) channel blockers. As a result, KYS05090, a most potent T-type Ca(2+) channel blocker, was found to be as potent as doxorubicin against some human cancer cells without acute toxicity. Therefore, this letter provides the biological results that T-type calcium channel is important in regulating the important cellular phenotype transition leading to cell proliferation, and thus novel T-type Ca(2+) channel blocker presents new prospects for cancer treatment.

Geometry-dependent behavior of fibroblast cells in three-dimensional silicon microstructures

understanding the relationship between the cell and the substrate in microenvironments is a critical issue in cell biology research. In this paper, we report the response of HS68 normal human foreskin fibroblast cells to three-dimensional silicon microstructures, which are designed and fabricated using a single-mask fabrication technique. Our device composed of a network of microfluidic channels and microchambers with different widths and depths. Our results show that human fibroblast cells do not tend to go inside microchambers having isotropic cross sections and curved sidewalls, and moreover, their growth rate decreases as the depth increases. The growth rate decline has been utilized as a new method to create patterned cell culture.

T-type Ca2+ channel expression in human esophageal carcinomas: a functional role in proliferation

In the present study the role of T-type Ca(2+) channels in cancer cell proliferation was examined. Seventeen human esophageal cancer cell lines were screened for T-type channels using RT-PCR and voltage-clamp recordings. mRNAs for all three T-type channel alpha(1)-subunits (alpha(1G), alpha(1H), and alpha(1I)) were detected in all 17 cell lines: either alpha(1H) alone, alpha(1H) and alpha(1G), or all three T-type alpha(1)-subunits. Eleven cell lines were further subjected to voltage-clamp recordings: one, i.e. the TE8 cell line, was found to exhibit a typical T-type current while others exhibited a minimal or no T-type current. Cell proliferation assays were performed in the presence or absence of T-type channel blocker mibefradil in KYSE150, KYSE180 and TE1 cells expressing mRNA for T-type channel alpha(1)-subunits but lacking T-type current, and TE8 cells exhibiting T-type current. Only TE8 cell proliferation was reduced by mibefradil. Silencing the alpha(1G)-gene that encodes functional T-type Ca(2+) channels in TE8 cells with type-specific shRNA transduction also significantly decreased TE8 cell proliferation. The reduction of cell proliferation in TE8 cells was found to be associated with an up-regulation of p21(CIP1). Moreover, p53 silencing nearly abolished the up-regulation of p21(CIP1) resulting from mibefradil T-type channel blockade. Together, these findings suggest a functional role of T-type channels in certain esophageal carcinomas, and that inhibition of T-type channels reduces cell proliferation via a p53-dependent p21(CIP1) pathway.

The Ca(2+) channel antagonists mibefradil and pimozide inhibit cell growth via different cytotoxic mechanisms

We show that mitogenic cells expressing T-type Ca(2+) channels (T-channels) are more sensitive to the antiproliferative effects of the drugs pimozide and mibefradil than cells without significant T-channel expression. The growth of Y79 and WERI-Rb1 retinoblastoma cells, as well as MCF7 breast cancer epithelial cells, all of which express T-channel current and mRNA for T-channel subunits, is inhibited by pimozide and mibefradil with IC(50) values between 0.6 and 1.5 microM. Proliferation of glioma C6 cells, which show little T-channel expression, is less sensitive to these drugs (IC(50) = 8 and 5 microM for pimozide and mibefradil, respectively). Neither drug seems to alter cell cycle or the expression of cyclins. Although this strong correlation between T-channel expression and growth inhibition exists, the following results suggest that the drugs inhibit cell growth via different cytotoxic pathways: 1) pimozide and mibefradil have additive effects on T-channel current inhibition, whereas the antiproliferative activity of the drugs together is synergistic; 2) an increase in the number of apoptotic Y79 and MCF7 cells and a decrease in the mRNA for the antiapoptotic gene Bcl-2 is detected only in pimozide-treated cells, whereas in mibefradil-treated cells, the toxicity is primarily necrotic; and 3) growth inhibition by mibefradil is reduced in Y79 cells transfected with T-channel antisense and in differentiated Y79 cells (which have decreased T-channel expression), but growth inhibition by pimozide is affected to a lesser extent. These results suggest that pimozide and mibefradil inhibit cell proliferation via different cytotoxic pathways and that in the case of pimozide, it is unlikely that this effect is mediated solely by T-channel inhibition.

T-Type calcium channel alpha1G and alpha1H subunits in human retinoblastoma cells and their loss after differentiation

Human retinoblastoma cells are multipotent retinal precursor cells capable of differentiating into photoreceptors, neurons, and glia. The current-voltage relation of the undifferentiated cells is dominated by a transient inward current that disappears shortly after differentiation. In 20 mM Ba(2+)-containing bath solutions, the current has an activation midpoint near -25 mV and appears to be fully inactivated at -20 mV. Sr(2+) and Ca(2+) are preferred charge carriers relative to Ba(2+), and the current vanishes in the absence of these divalent cations. Cd(2+) blocks the current with an IC(50) of 160 microM, and Ni(2+) blocks in a biphasic manner with IC(50)s of 22 and 352 microM. The current is unaffected when sodium is replaced with other monovalent cations, and it is insensitive to nifedipine, omega-conotoxin GVIA, omega-agatoxin IVA, and omega-conotoxin MVIIC. RT-PCR revealed the presence of alpha 1G and alpha 1H mRNA in undifferentiated cells, but following differentiation, a striking reduction of both alpha 1G and alpha 1H mRNA was found, and this was paralleled by the loss of T-type Ca channel currents. alpha 1I subunit mRNA levels were low in undifferentiated and differentiated cells. These results suggest that T-type Ca channels could play a role in undifferentiated retinoblastoma cell physiology since alpha 1G and alpha 1H Ca channel subunit expression is reduced in cells that have differentiated and exited the cell cycle.

Potassium channel antagonists influence porcine granulosa cell proliferation, differentiation, and apoptosis

This investigation determined the effects of K(+) channel antagonists on proliferation, differentiation, and apoptosis of porcine granulosa cells. The drugs screened for functional effects included the class III antiarrhythmic agents MK-499 and clofilium, the chromanol I(Ks) antagonist 293B, the benzodiazepine I(Ks) antagonists L-735,821 and L-768,673, and the peptidyl toxins charybdotoxin (CTX) and margatoxin (MTX). Granulosa cell proliferation and differentiation were assessed by serial measurements of cell number and progesterone accumulation in the culture media, respectively. Granulosa cell apoptosis was evaluated using flow cytometry. Additional information about drug effects was obtained by immunoblotting to detect expression of proliferating cell nuclear antigen, p27(kip1) and the caspase-3 substrate poly(ADP-ribose) polymerase. The ERG channel antagonist MK-499 had no functional effects on cultured granulosa cells. However, the broad spectrum K(+) channel antagonist clofilium decreased, in a concentration-dependent fashion, the number of viable granulosa cells cultured, and these effects were associated with induction of apoptosis. All three I(Ks) antagonists (293B, L-735,821, and L-768,673) increased basal, but not FSH-enhanced progesterone accumulation on Day 1 after treatment without affecting the number of viable cells in culture, an effect that was blocked by pimozide. In contrast, CTX and MTX increased the number of viable cells in FSH-stimulated cultures on Day 3 after treatment without affecting progesterone output per cell. These data demonstrate that selective antagonism of granulosa cell K(+) channels with distinct molecular correlates, electrophysiological properties, and expression patterns can influence differential granulosa cell proliferation, steroidogenic capability, and apoptosis. Thus, K(+) channels may represent pharmacological targets for affecting Granulosa cell function and oocyte maturation, in vivo or in vitro.

Growth arrest and cell death in the breast tumor cell in response to ionizing radiation and chemotherapeutic agents which induce DNA damage

Breast tumor cells are relatively refractory to apoptosis in response to modalities which induce DNA damage such as ionizing radiation and the topoisomerase II inhibitor, adriamycin. Various factors which may modulate the apoptotic response to DNA damage include the p53 status of the cell, levels and activity of the Bax and Bcl-2 families of proteins, activation of NF-kappa B, relative levels of insulin like growth factor and insulin-like growth factor binding proteins, activation of MAP kinases and PI3/Akt kinases, (the absence of) ceramide generation and the CD95 (APO1/Fas) signaling pathway. Prolonged growth arrest associated with replicative senescence may represent an alternative and reciprocal response to DNA-damage induced apoptosis that is p53 and/or p21waf1/cip1 dependent while delayed apoptosis may occur in p53 mutant breast tumor cells which fail to maintain the growth-arrested state. Clearly, the absence of an immediate apoptotic response to DNA damage does not eliminate other avenues leading to cell death and loss of self-renewal capacity in the breast tumor cell. Nevertheless, prolonged growth arrest (even if ultimately succeeded by apoptotic or necrotic cell death) could provide an opportunity for subpopulations of breast tumor cells to recover proliferative capacity and to develop resistance to subsequent clinical intervention.

Co-culture with human fibroblasts increases the radiosensitivity of MCF-7 mammary carcinoma cells in collagen gels

The growth and differentiation of normal and neoplastic epithelial cells may be regulated by the presence of adjacent normal tissues and cells, particularly stromal fibroblasts. However, the influence of normal fibroblast-tumor cell interactions on the response of malignant epithelial cells to radiation has not been adequately investigated nor has the possible role played by a 3-D environment in such modulation. We addressed this question by embedding MCF-7 mammary carcinoma cells into a collagen lattice, alone or mixed with HSF human dermal fibroblasts, and kept the gels anchored to the plastic surface or suspended in the culture medium. Some gels served as controls and others were irradiated with 6 MV photons fractionated into 3 daily doses totaling 5 or 10 Gy. After 2 or 7 days from the last treatment (7 or 12 days in culture, respectively), gels were processed in 1 of 2 ways: overall cell survival was determined by the MTT assay, while the survival of MCF-7 cells was selectively detected by a clonogenicity assay. Under these experimental conditions, we found that, in the presence of HSF fibroblasts, the growth of MCF-7 cells was restrained and radiosensitivity increased compared with MCF-7 cells cultured alone. For example, while the average number of MCF-7 foci/gel recovered from control gels with MCF-7 cells alone was 2,460 on day 7 and 3, 290 on day 12 of culture, it was 4 to 5 times lower (p < 0.001) in control gels with mixed MCF-7 and HSF cells. Radiation affected severely the survival of MCF-7 cells in all experimental groups but not sufficiently to mask the differences. For example, following exposure to the low dose of 5 Gy, the average number of MCF-7 foci/gel recovered from MCF-7-containing gels was 590 on day 7 and 329 on day 12 of culture, whereas numbers from the gels containing mixed MCF-7 and HSF cells were only 218 and 73, respectively (p < 0. 003 in both cases). HSF fibroblasts did not grow in our system, but they contracted strongly anchored and floating gels.