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Oncotarget Jan 2017Cancer stem cells (CSCs) play major roles in cancer initiation, metastasis, recurrence and therapeutic resistance. Targeting CSCs represents a promising strategy for...
Cancer stem cells (CSCs) play major roles in cancer initiation, metastasis, recurrence and therapeutic resistance. Targeting CSCs represents a promising strategy for cancer treatment. The purpose of this study was to identify selective inhibitors of breast CSCs (BCSCs). We carried out a cell-based phenotypic screening with cell viability as a primary endpoint, using a collection of 2,546 FDA-approved drugs and drug-like molecules in spheres formed by malignant human breast gland-derived cells (HMLER-shEcad cells, representing BCSCs) and control immortalized non-tumorigenic human mammary cells (HMLE cells, representing normal stem cells). 19 compounds were identified from screening. The chemically related molecules benztropine mesylate and deptropine citrate were selected for further validation and both potently inhibited sphere formation and self-renewal of BCSCs in vitro. Benztropine mesylate treatment decreased cell subpopulations with high ALDH activity and with a CD44+/CD24- phenotype. In vivo, benztropine mesylate inhibited tumor-initiating potential in a 4T1 mouse model. Functional studies indicated that benztropine mesylate inhibits functions of CSCs via the acetylcholine receptors, dopamine transporters/receptors, and/or histamine receptors. In summary, our findings identify benztropine mesylate as an inhibitor of BCSCs in vitro and in vivo. This study also provides a screening platform for identification of additional anti-CSC agents.
Topics: Animals; Antineoplastic Agents; Antiparkinson Agents; Benztropine; Biomarkers; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Self Renewal; Cell Survival; Disease Models, Animal; Drug Repositioning; Drug Screening Assays, Antitumor; Female; Humans; Immunophenotyping; Mice; Neoplastic Stem Cells; Small Molecule Libraries; Spheroids, Cellular; Tumor Cells, Cultured; Xenograft Model Antitumor Assays
PubMed: 27894093
DOI: 10.18632/oncotarget.13537 -
Human embryonic stem cell-derived cardiomyocyte platform screens inhibitors of SARS-CoV-2 infection.Communications Biology Jul 2021Patients with cardiovascular comorbidities are more susceptible to severe infection with SARS-CoV-2, known to directly cause pathological damage to cardiovascular...
Patients with cardiovascular comorbidities are more susceptible to severe infection with SARS-CoV-2, known to directly cause pathological damage to cardiovascular tissue. We outline a screening platform using human embryonic stem cell-derived cardiomyocytes, confirmed to express the protein machinery critical for SARS-CoV-2 infection, and a SARS-CoV-2 spike-pseudotyped virus system. The method has allowed us to identify benztropine and DX600 as novel inhibitors of SARS-CoV-2 infection in a clinically relevant stem cell-derived cardiomyocyte line. Discovery of new medicines will be critical for protecting the heart in patients with SARS-CoV-2, and for individuals where vaccination is contraindicated.
Topics: Antiviral Agents; Benztropine; Drug Evaluation, Preclinical; Human Embryonic Stem Cells; Humans; Myocytes, Cardiac; Peptides; SARS-CoV-2
PubMed: 34326460
DOI: 10.1038/s42003-021-02453-y -
Journal of Neurochemistry May 2004The different psychomotor-stimulant effects of cocaine, GBR12909, and benztropine may partially stem from their different molecular actions on the dopamine transporter...
The different psychomotor-stimulant effects of cocaine, GBR12909, and benztropine may partially stem from their different molecular actions on the dopamine transporter (DAT). To explore this possibility, we examined binding of these inhibitors to mutated DATs with altered Na(+) dependence of DAT activities and with enhanced binding of a cocaine analog, [(3)H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (CFT). In [(3)H]CFT competition assays with intact cells, the mutation-induced change in the ability of Na(+) to enhance the apparent affinity of CFT, cocaine, GBR12909, and benztropine was inhibitor-independent. Thus, for the four inhibitors, the curve of [Na(+)] versus apparent ligand affinity was steeper at W84L compared with wild type, shallower at D313N, and flat at W84LD313N. At each mutant, the apparent affinity of CFT and cocaine was enhanced regardless of whether Na(+) was present. However, the apparent affinity of GBR12909 and benztropine for W84L was reduced in the absence of Na(+) but near normal in the presence of 130 mm Na(+), and that for D313N and W84LD313N was barely changed. At the single mutants, the alterations in Na(+) dependence and apparent affinity of the four inhibitors were comparable between [(3)H]CFT competition assays and [(3)H]dopamine uptake inhibition assays. These results demonstrate that DAT inhibitors producing different behavioral profiles can respond in an opposite way when residues of the DAT protein are mutated. For GBR12909 and benztropine, their cocaine-like changes in Na(+) dependence suggest that they prefer a DAT state similar to that for cocaine. However, their cocaine-unlike changes in apparent affinity argue that they, likely via their diphenylmethoxy moiety, share DAT binding epitopes that are different from those for cocaine.
Topics: Amino Acid Substitution; Benztropine; Binding, Competitive; Cell Line; Cocaine; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopamine Uptake Inhibitors; Humans; Kidney; Ligands; Membrane Glycoproteins; Membrane Transport Proteins; Muscarinic Antagonists; Mutagenesis, Site-Directed; Nerve Tissue Proteins; Piperazines; Protein Binding; Sodium; Structure-Activity Relationship; Zinc
PubMed: 15140185
DOI: 10.1111/j.1471-4159.2004.02386.x -
The Journal of Pharmacology and... Jul 2013The dopamine transporter (DAT) is a sodium-coupled symporter protein responsible for modulating the concentration of extraneuronal dopamine in the brain. The DAT is a... (Review)
Review
The dopamine transporter (DAT) is a sodium-coupled symporter protein responsible for modulating the concentration of extraneuronal dopamine in the brain. The DAT is a principle target of various psychostimulant, nootropic, and antidepressant drugs, as well as certain drugs used recreationally, including the notoriously addictive stimulant cocaine. DAT ligands have traditionally been divided into two categories: cocaine-like inhibitors and amphetamine-like substrates. Whereas inhibitors block monoamine uptake by the DAT but are not translocated across the membrane, substrates are actively translocated and trigger DAT-mediated release of dopamine by reversal of the translocation cycle. Because both inhibitors and substrates increase extraneuronal dopamine levels, it is often assumed that all DAT ligands possess an addictive liability equivalent to that of cocaine. However, certain recently developed ligands, such as atypical benztropine-like DAT inhibitors with reduced or even a complete lack of cocaine-like rewarding effects, suggest that addictiveness is not a constant property of DAT-affecting compounds. These atypical ligands do not conform to the classic preconception that all DAT inhibitors (or substrates) are functionally and mechanistically alike. Instead, they suggest the possibility that the DAT exhibits some of the ligand-specific pleiotropic functional qualities inherent to G-protein-coupled receptors. That is, ligands with different chemical structures induce specific conformational changes in the transporter protein that can be differentially transduced by the cell, ultimately eliciting unique behavioral and psychological effects. The present overview discusses compounds with conformation-specific activity, useful not only as tools for studying the mechanics of dopamine transport, but also as leads for medication development in addictive disorders.
Topics: Allosteric Regulation; Animals; Biological Transport; Brain; Dopamine; Dopamine Plasma Membrane Transport Proteins; Humans; Ligands; Membrane Transport Modulators; Nerve Tissue Proteins; Neurons; Protein Conformation; Protein Isoforms
PubMed: 23568856
DOI: 10.1124/jpet.111.191056 -
The Journal of Pharmacology and... Sep 2018Atypical dopamine transporter (DAT) inhibitors, despite high DAT affinity, do not produce the psychomotor stimulant and abuse profile of standard DAT inhibitors such as...
Atypical dopamine transporter (DAT) inhibitors, despite high DAT affinity, do not produce the psychomotor stimulant and abuse profile of standard DAT inhibitors such as cocaine. Proposed contributing features for those differences include off-target actions, slow onsets of action, and ligand bias regarding DAT conformation. Several 3-(4',4''-difluoro-diphenylmethoxy)tropanes were examined, including those with the following substitutions: -(indole-3''-ethyl)- (GA1-69), -()-2''-amino-3''-methyl--butyl- (GA2-50), -2''aminoethyl- (GA2-99), and -(cyclopropylmethyl)- (JHW013). These compounds were previously reported to have rapid onset of behavioral effects and were presently evaluated pharmacologically alone or in combination with cocaine. DAT conformational mode was assessed by substituted-cysteine accessibility and molecular dynamics (MD) simulations. As determined by substituted-cysteine alkylation, all BZT analogs except GA2-99 showed bias for a cytoplasmic-facing DAT conformation, whereas cocaine stabilized the extracellular-facing conformation. MD simulations suggested that several analog-DAT complexes formed stable R85-D476 "outer gate" bonds that close the DAT to extracellular space. GA2-99 diverged from this pattern, yet had effects similar to those of other atypical DAT inhibitors. Apparent DAT association rates of the BZT analogs in vivo were slower than that for cocaine. None of the compounds was self-administered or stimulated locomotion, and each blocked those effects of cocaine. The present findings provide more detail on ligand-induced DAT conformations and indicate that aspects of DAT conformation other than "open" versus "closed" may facilitate predictions of the actions of DAT inhibitors and may promote rational design of potential treatments for psychomotor-stimulant abuse.
Topics: Animals; Behavior, Animal; Benztropine; Dopamine Plasma Membrane Transport Proteins; Male; Molecular Dynamics Simulation; Nitrogen; Protein Conformation; Rats; Rats, Sprague-Dawley
PubMed: 29945932
DOI: 10.1124/jpet.118.250498 -
Identification of the benztropine analog [I]GA II 34 binding site on the human dopamine transporter.Neurochemistry International Feb 2019The dopamine transporter (DAT) is a neuronal membrane protein that is responsible for reuptake of dopamine (DA) from the synapse and functions as a major determinant in...
The dopamine transporter (DAT) is a neuronal membrane protein that is responsible for reuptake of dopamine (DA) from the synapse and functions as a major determinant in control of DA neurotransmission. Cocaine and many psychostimulant drugs bind to DAT and block reuptake, inducing DA overflow that forms the neurochemical basis for euphoria and addiction. Paradoxically, however, some ligands such as benztropine (BZT) bind to DAT and inhibit reuptake but do not produce these effects, and it has been hypothesized that differential mechanisms of binding may stabilize specific transporter conformations that affect downstream neurochemical or behavioral outcomes. To investigate the binding mechanisms of BZT on DAT we used the photoaffinity BZT analog [I]N-[n-butyl-4-(4‴-azido-3‴-iodophenyl)]-4',4″-difluoro-3α-(diphenylmethoxy)tropane ([I]GA II 34) to identify the site of cross-linking and predict the binding pose relative to that of previously-examined cocaine photoaffinity analogs. Biochemical findings show that adduction of [I]GA II 34 occurs at residues Asp79 or Leu80 in TM1, with molecular modeling supporting adduction to Leu80 and a pharmacophore pose in the central S1 site similar to that of cocaine and cocaine analogs. Substituted cysteine accessibility method protection analyses verified these findings, but identified some differences in structural stabilization relative to cocaine that may relate to BZT neurochemical outcomes.
Topics: Benztropine; Binding Sites; Cocaine; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopamine Uptake Inhibitors; Humans; Iodine Radioisotopes; Structure-Activity Relationship
PubMed: 30125594
DOI: 10.1016/j.neuint.2018.08.008 -
Canadian Medical Association Journal Apr 1983
Topics: Adult; Benztropine; Body Temperature Regulation; Chlorpromazine; Heat Exhaustion; Humans; Male; Psychotropic Drugs; Schizophrenia; Thermosensing
PubMed: 6831343
DOI: No ID Found -
Cureus Jul 2022In this case report, we describe a rather unique case of a 37-year-old male patient suffering from schizophrenia who presented with a fixed upwards gaze diagnosed as...
In this case report, we describe a rather unique case of a 37-year-old male patient suffering from schizophrenia who presented with a fixed upwards gaze diagnosed as oculogyric crisis (OGC). This presentation was attributed to the effects of risperidone, a second-generation antipsychotic, while concomitantly taking benztropine mesylate. The latter is a medication commonly used to prevent dystonia in this type of patient population. Interestingly, the dose of risperidone was minimal, and side effects were not expected, making this presentation rare and not often cited or represented in the medical literature, given that second-generation antipsychotics are known to have a safer side effect profile when compared to their counterparts. We also aim to provide a review of the literature on this topic and describe the approach to diagnosis and treatment of such.
PubMed: 36035042
DOI: 10.7759/cureus.27217 -
Cureus Feb 2021Although data on the prevalence of anticholinergic misuse is scarce, it has been reported among psychiatric patients. Anticholinergic drugs can act as potent indirect...
Although data on the prevalence of anticholinergic misuse is scarce, it has been reported among psychiatric patients. Anticholinergic drugs can act as potent indirect dopamine agonists in the limbic system, a mechanism that has been hypothesized to explain their misuse potential among patients. In psychiatric practice settings, the use of typical antipsychotics in conjunction with anticholinergics is common, with the latter mainly used to manage extrapyramidal side effects of the former. Haloperidol is a first-generation (typical) antipsychotic with weak anticholinergic properties that may sometimes be potentiated when it is used in combination with other anticholinergic medications. This combination can induce significant gastrointestinal hypomotility, constipation, and rarely even paralytic ileus. We present the case of a 67-year-old African American male with a history of schizophrenia, benign prostatic hyperplasia, and essential hypertension, who abruptly started misusing benztropine, without any prior history of a substance use disorder. This case highlights the importance of obtaining a detailed history when previously stable psychiatric patients develop acute physical symptoms. It also illustrates the importance of care coordination among care providers and the central role of the psychiatrist in the care of patients with medical comorbidities.
PubMed: 33758719
DOI: 10.7759/cureus.13434 -
The Mental Health Clinician Jan 2021Dosing recommendations for paliperidone long-acting injectable antipsychotic (LAIA) do not include oral antipsychotic (OAP) overlap; however, OAPs are often given...
INTRODUCTION
Dosing recommendations for paliperidone long-acting injectable antipsychotic (LAIA) do not include oral antipsychotic (OAP) overlap; however, OAPs are often given concurrently despite limited evidence describing both the risks and benefits of this practice.
METHODS
A retrospective chart review was conducted in patients initiated on paliperidone palmitate (PP) during a psychiatric hospitalization to compare patients who received OAP overlap versus those who did not. The primary outcome is the proportion of patients who receive prescription claims for benztropine, a medication commonly prescribed for extrapyramidal symptoms, at the time of LAIA discontinuation and 6 months postdischarge. Secondary outcomes include prescription claims for beta blockers and diphenhydramine, number of psychiatric emergency visits and hospitalizations, length of stay of the index hospitalization, frequency of LAIA discontinuation and the time to LAIA discontinuation.
RESULTS
There is a significant difference in the proportion of benztropine prescription claims in the OAP overlap group versus the no-overlap group at the time of LAIA discontinuation (30% vs 0%, = .046) but not at 6 months postdischarge. There are also significant differences in the number of psychiatric emergency visits (0.7 vs 0.1, = .02) and psychiatric hospitalizations (0.6 vs 0.1, = .029) at the time of LAIA discontinuation. No other differences are observed in defined secondary outcomes.
DISCUSSION
Patients who receive OAP overlap while receiving PP receive more benztropine and have more psychiatric emergency visits and hospitalizations than those treated without OAP. Larger studies with better control for confounding variables are needed to confirm these results.
PubMed: 33505820
DOI: 10.9740/mhc.2021.01.012