- 3-Chlorodiphenylamine activates cardiac troponin by a mechanism distinct from bepridil or TFP. [Journal Article]
- JGJ Gen Physiol 2018 Nov 15
- Despite extensive efforts spanning multiple decades, the development of highly effective Ca2+ sensitizers for the heart remains an elusive goal. Existing Ca2+ sensitizers have other targets in additi...
Despite extensive efforts spanning multiple decades, the development of highly effective Ca2+ sensitizers for the heart remains an elusive goal. Existing Ca2+ sensitizers have other targets in addition to cardiac troponin (cTn), which can lead to adverse side effects, such as hypotension or arrhythmias. Thus, there is a need to design Ca2+-sensitizing drugs with higher affinity and selectivity for cTn. Previously, we determined that many compounds based on diphenylamine (DPA) were able to bind to a cTnC-cTnI chimera with moderate affinity (Kd ∼10-120 µM). Of these compounds, 3-chlorodiphenylamine (3-Cl-DPA) bound most tightly (Kd of 10 µM). Here, we investigate 3-Cl-DPA further and find that it increases the Ca2+ sensitivity of force development in skinned cardiac muscle. Using NMR, we show that, like the known Ca2+ sensitizers, trifluoperazine (TFP) and bepridil, 3-Cl-DPA is able to bind to the isolated N-terminal domain (N-domain) of cTnC (Kd of 6 µM). However, while the bulky molecules of TFP and bepridil stabilize the open state of the N-domain of cTnC, the small and flexible 3-Cl-DPA molecule is able to bind without stabilizing this open state. Thus, unlike TFP, which drastically slows the rate of Ca2+ dissociation from the N-domain of isolated cTnC in a dose-dependent manner, 3-Cl-DPA has no effect on the rate of Ca2+ dissociation. On the other hand, the affinity of 3-Cl-DPA for a cTnC-TnI chimera is at least an order of magnitude higher than that of TFP or bepridil, likely because 3-Cl-DPA is less disruptive of cTnI binding to cTnC. Therefore, 3-Cl-DPA has a bigger effect on the rate of Ca2+ dissociation from the entire cTn complex than TFP and bepridil. Our data suggest that 3-Cl-DPA activates the cTn complex via a unique mechanism and could be a suitable scaffold for the development of novel treatments for systolic heart failure.
- Role of Overexpressed Transcription Factor FOXO1 in Fatal Cardiovascular Septal Defects in Patau Syndrome: Molecular and Therapeutic Strategies. [Journal Article]
- IJInt J Mol Sci 2018 Nov 10; 19(11)
- Patau Syndrome (PS), characterized as a lethal disease, allows less than 15% survival over the first year of life. Most deaths owe to brain and heart disorders, more so due to septal defects because ...
Patau Syndrome (PS), characterized as a lethal disease, allows less than 15% survival over the first year of life. Most deaths owe to brain and heart disorders, more so due to septal defects because of altered gene regulations. We ascertained the cytogenetic basis of PS first, followed by molecular analysis and docking studies. Thirty-seven PS cases were referred from the Department of Pediatrics, King Abdulaziz University Hospital to the Center of Excellence in Genomic Medicine Research, Jeddah during 2008 to 2018. Cytogenetic analyses were performed by standard G-band method and trisomy13 were found in all the PS cases. Studies have suggested that genes of chromosome 13 and other chromosomes are associated with PS. We, therefore, did molecular pathway analysis, gene interaction, and ontology studies to identify their associations. Genomic analysis revealed important chr13 genes such as FOXO1, Col4A1, HMGBB1, FLT1, EFNB2, EDNRB, GAS6, TNFSF1, STARD13, TRPC4, TUBA3C, and TUBA3D, and their regulatory partners on other chromosomes associated with cardiovascular disorders, atrial and ventricular septal defects. There is strong indication of involving FOXO1 (Forkhead Box O1) gene-a strong transcription factor present on chr13, interacting with many septal defects link genes. The study was extended using molecular docking to find a potential drug lead for overexpressed FOXO1 inhibition. The phenothiazine and trifluoperazine showed efficiency to inhibit overexpressed FOXO1 protein, and could be potential drugs for PS/trisomy13 after validation.
- Effects of Phenothiazines on Aldehyde Oxidase Activity Towards Aldehydes and N-Heterocycles: an In Vitro and In Silico Study. [Journal Article]
- EJEur J Drug Metab Pharmacokinet 2018 Oct 31
- CONCLUSIONS: The five studied phenothiazine drugs showed dual inhibitory effects on AOX activity towards aldehydes and N-heterocycles as two major classes of enzyme substrates. Most of the interactions between the phenothiazine-related drugs and AOX in the binding pocket showed a hydrophobic nature.
- Photochemical and Pharmacokinetic Characterization of Orally Administered Chemicals to Evaluate Phototoxic Risk. [Journal Article]
- JPJ Pharm Sci 2018 Oct 16
- This study aimed to verify the applicability of a proposed photosafety screening system based on a reactive oxygen species (ROS) assay and a cassette-dosing pharmacokinetic (PK) study to chemicals wi...
This study aimed to verify the applicability of a proposed photosafety screening system based on a reactive oxygen species (ROS) assay and a cassette-dosing pharmacokinetic (PK) study to chemicals with wide structural diversity. The orally taken chemicals, erythromycin, gatifloxacin, 8-methoxypsoralen (MOP), pirfenidone (PFD), trifluoperazine (TFP), and voriconazole (VRZ), were selected as test compounds. The ROS assay was conducted to evaluate their photoreactivity, and all test compounds excluding erythromycin generated significant ROS under simulated sunlight exposure. According to the ROS data, TFP had potent photoreactivity, and the photoreactivity of 4 other compounds was judged to be moderate. Regarding the oral cassette-dosing PK test in rats, the skin deposition of MOP, PFD, and VRZ was relatively high, and gatifloxacin and TFP exhibited moderate skin deposition properties. Based on the ROS and PK data of test compounds, PFD and TFP were judged to be potent phototoxic compounds, and MOP and VRZ were deduced to have phototoxic risk. The predicted phototoxic risk of test compounds by proposed screening was mostly in agreement with observed in vivo phototoxicity in the rat skin. The proposed screening system could provide reliable photosafety information on orally administered compounds with wide structural diversity.
- Trifluoperazine prevents FOXO1 nuclear excretion and reverses doxorubicin-resistance in the SHG44/DOX drug-resistant glioma cell line. [Journal Article]
- IJInt J Mol Med 2018; 42(6):3300-3308
- As a tumor suppressor, Forkhead box O1 (FOXO1) is located in the nucleus where it regulates gene expression and inhibits tumor progression. However, the antitumor effects of FOXO1 are attenuated in s...
As a tumor suppressor, Forkhead box O1 (FOXO1) is located in the nucleus where it regulates gene expression and inhibits tumor progression. However, the antitumor effects of FOXO1 are attenuated in several tumors due to its translocation from the nucleus to the cytoplasm. Trifluoperazine (TFP) is able to reverse tumor drug resistance by inhibiting multidrug resistance (MDR), however, the detailed molecular mechanisms by which this occurs remain to be fully elucidated. In the present study, the doxorubicin (DOX)‑resistant SHG44/DOX glioma cell line was established. The results showed that TFP promoted DOX‑induced cytotoxicity, cell cycle arrest and early apoptosis using a Cell Counting Kit‑8 and flow cytometry. In vivo experiments also demonstrated that DOX combined with TFP reduced tumor volumes and proliferation indices, and led to higher protein levels of FOXO1. In addition, TFP inhibited the nuclear exclusion of FOXO1, contributing toward the downregulation of MDR genes and an increase in intracellular DOX concentrations by reverse transcription‑quantitative polymerase chain reaction, western blot analysis, immunofluorescence and spectrophotometer analysis. Therefore, TFP may inhibit DOX resistance by stimulating FOXO1 nuclear translocation and suppressing MDF genes in SHG44/DOX cells, contributing to promising clinical prospects for tumor chemotherapy.
- The antipsychotic agent trifluoperazine hydrochloride suppresses triple-negative breast cancer tumor growth and brain metastasis by inducing G0/G1 arrest and apoptosis. [Journal Article]
- CDCell Death Dis 2018 Sep 26; 9(10):1006
- Women with aggressive triple-negative breast cancer (TNBC) are at high risk of brain metastasis, which has no effective therapeutic option partially due to the poor penetration of drugs across the bl...
Women with aggressive triple-negative breast cancer (TNBC) are at high risk of brain metastasis, which has no effective therapeutic option partially due to the poor penetration of drugs across the blood-brain barrier. Trifluoperazine (TFP) is an approved antipsychotic drug with good bioavailability in brain and had shown anticancer effect in several types of cancer. It drives us to investigate its activities to suppress TNBC, especially the brain metastasis. In this study, we chose three TNBC cell lines MDA-MB-468, MDA-MB-231, and 4T1 to assess its anticancer activities along with the possible mechanisms. In vitro, it induced G0/G1 cell cycle arrest via decreasing the expression of both cyclinD1/CDK4 and cyclinE/CDK2, and stimulated mitochondria-mediated apoptosis. In vivo, TFP suppressed the growth of subcutaneous xenograft tumor and brain metastasis without causing detectable side effects. Importantly, it prolonged the survival of mice bearing brain metastasis. Immunohistochemical analysis of Ki67 and cleaved caspase-3 indicated TFP could suppress the growth and induce apoptosis of cancer cells in vivo. Taken together, TFP might be a potential available drug for treating TNBC with brain metastasis, which urgently needs novel treatment options.
- Elucidation of the crystal structure of FabD from the multidrug-resistant bacterium Acinetobacter baumannii. [Journal Article]
- BBBiochem Biophys Res Commun 2018 Oct 20; 505(1):208-214
- Bacterial fatty acid synthesis (FAS) has been extensively studied as a potential target of antimicrobials. In FAS, FabD mediates transacylation of the malonyl group from malonyl-CoA to acyl-carrier p...
Bacterial fatty acid synthesis (FAS) has been extensively studied as a potential target of antimicrobials. In FAS, FabD mediates transacylation of the malonyl group from malonyl-CoA to acyl-carrier protein (ACP). The mounting threat of nosocomial infection by multidrug-resistant Acinetobacter baumannii warrants a deeper understanding of its essential cellular mechanisms, which could lead to effective control of this highly competent pathogen. The molecular mechanisms involved in A. baumannii FAS are poorly understood, and recent research has suggested that Pseudomonas aeruginosa, a closely related nosocomial pathogen of A. baumannii, utilizes FAS to produce virulence factors. In this study, we solved the crystal structure of A. baumannii FabD (AbFabD) to provide a platform for the development of new antibacterial agents. Analysis of the structure of AbFabD confirmed the presence of highly conserved active site residues among bacterial homologs. Binding constants between AbFabD variants and A. baumannii ACP (AbACP) revealed critical conserved residues Lys195 and Lys200 involved in AbACP binding. Computational docking of a potential inhibitor, trifluoperazine, revealed a unique inhibitor-binding pocket near the substrate-binding site. The structural study presented herein will be useful for the structure-based design of potent AbFabD inhibitors.
- Role of ATP during the initiation of microvascularization: acceleration of an autocrine sensing mechanism facilitating chemotaxis by inorganic polyphosphate. [Journal Article]
- BJBiochem J 2018 Oct 31; 475(20):3255-3273
- The in vitro tube formation assay with human umbilical vein endothelial cells (HUVEC) was applied to identify the extra- and intracellular sources of metabolic energy/ATP required for cell migration ...
The in vitro tube formation assay with human umbilical vein endothelial cells (HUVEC) was applied to identify the extra- and intracellular sources of metabolic energy/ATP required for cell migration during the initial stage of microvascularization. Extracellularly, the physiological energy-rich polymer, inorganic polyphosphate (polyP), applied as biomimetic amorphous calcium polyP microparticles (Ca-polyP-MP), is functioning as a substrate for ATP generation most likely via the combined action of the alkaline phosphatase (ALP) and the adenylate kinase (AK). The linear Ca-polyP-MP with a size of 40 phosphate units, close to the polyP in the acidocalcisomes in the blood platelets, were found to increase endothelial cell tube formation, as well as the intracellular ATP levels. Depletion of extracellular ATP with apyrase suppressed tube formation during the initial incubation period. Inhibition experiments revealed that inhibitors (levamisole and Ap5A) of the enzymes involved in extracellular ATP generation strongly reduce the Ca-polyP-MP-induced tube formation. The stimulatory effect of Ca-polyP-MP was also diminished by the glycolysis inhibitor oxamate and trifluoperazine which blocks endocytosis, as well as by MRS2211, an antagonist of the P2Y13 receptor. Oligomycin, an inhibitor of the mitochondrial F0F1-ATP synthase, displayed no effect at lower concentrations on tube formation. Electron microscopic data revealed that after cellular uptake, the Ca-polyP-MP accumulate close to the cell membrane. We conclude that in HUVEC exposed to polyP, ATP is formed extracellularly via the coupled ALP-AK reaction, and intracellularly during glycolysis. The results suggest an autocrine signaling pathway of ATP with polyP as an extracellular store of metabolic energy for endothelial cell migration during the initial vascularization process.
- StatPearls [BOOK]
- BOOKStatPearls Publishing: Treasure Island (FL)
- First-generation antipsychotics are dopamine receptor antagonists (DRA) and are known as typical antipsychotics. They include phenothiazines (trifluoperazine, perphenazine, prochlorperazine, acetophe...
First-generation antipsychotics are dopamine receptor antagonists (DRA) and are known as typical antipsychotics. They include phenothiazines (trifluoperazine, perphenazine, prochlorperazine, acetophenazine, triflupromazine, mesoridazine), butyrophenones (Haloperidol), thioxanthenes (thiothixene, chlorprothixene), dibenzoxazepines (loxapine), dihydroindole (molindone), and diphenylbutylpiperidines (pimozide).
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- Interaction of calmodulin with poly(acrylic acid) brushes: Effects of high pressure, pH-value and ligand binding. [Journal Article]
- CSColloids Surf B Biointerfaces 2018 Nov 01; 171:478-484
- Poly(acrylic acid) (PAA) brushes are well-known to interact with proteins in an ionic strength-dependent way. Moreover, they provide a native-like environment that largely maintains the secondary str...
Poly(acrylic acid) (PAA) brushes are well-known to interact with proteins in an ionic strength-dependent way. Moreover, they provide a native-like environment that largely maintains the secondary structure and biological activity of adsorbed proteins. Recently, it has been shown that the application of high pressure can lead to a reduced protein adsorption at a PAA brush in the case of a positively charged protein. Here, we analyze the effect of pressure on the interactions between a protein and a PAA brush in more detail. We use calmodulin as model protein that has a negative net charge at neutral pH-value and determine the degree of adsorption at a planar PAA brush applying total internal reflection fluorescence (TIRF) spectroscopy. Remarkably, the degree of calmodulin adsorption at a PAA brush is increasing with increasing pressure, when the protein is negatively charged. However, at low pH-value, where calmodulin is positively charged, high pressure leads to a partial desorption of the protein. Moreover, in the presence of trifluoperazine, which binds to calmodulin as a ligand, the pressure effect is diminished. The results of this study indicate that protein adsorption at a PAA brush at the "wrong" side of the isoelectric point, i.e. under net electrostatic repulsion, can involve a volume reduction that is favored under high pressure. It is suggested that this volume reduction is related to a hydration of counterions that are released from the PAA chains and the protein surface. In contrast, at pH-values close to the isoelectric point, the obtained data are consistent with a charge regulation mechanism that involves a volume increase. Thus, the application of high pressure in combination with pH-variation, as carried out in this study, provides the volume changes of adsorption that need to be consistent with any proposed mechanism of protein interaction with a PAA brush.