Check out our New Publishers' Select for Free Articles

Biochemical Pharmacology (v.81, #9)

Editorial Advisory Board (pp. iii).

Glycine transporter 1 as a potential therapeutic target for schizophrenia-related symptoms: Evidence from genetically modified mouse models and pharmacological inhibition by Hanns Möhler; Detlev Boison; Philipp Singer; Joram Feldon; Meike Pauly-Evers; Benjamin K. Yee (pp. 1065-1077).

Inhibiting glycine transporters, GlyT1, but not GlyT2, enhances NMDA-receptor-mediated neurotransmission, thus offers an effective strategy against glutamatergic hypofunction implicated in schizophrenia, especially in the genesis of cognitive and negative symptoms.Schizophrenia is characterized by positive symptoms such as hallucinations, negative symptoms such as blunted affect, and symptoms of cognitive deficiency such as deficits in working memory and selective attention. N-methyl-d-aspartate receptor (NMDAR) hypofunction has been implicated in all three pathophysiological aspects of the disease. Due to the severe side effects of direct NMDAR agonists, targeting the modulatory co-agonist glycine-B site of the NMDAR is considered to be a promising strategy to ameliorate NMDAR hypofunction. To assess the antipsychotic and pro-cognitive potential of this approach, we examine the strategies designed to enhance glycine-B site occupancy through glycine transporter 1 (GlyT1) blockade. Among the existing transgenic mouse models with GlyT1 deficits, the one specifically targeting forebrain neuronal GlyT1 has yielded the most promising data on cognitive enhancement. Parallel advances in the pharmacology of GlyT1 inhibition point not only to an enhancement of attention, learning and memory but also include suggestions of mood enhancing effects that might be valuable for treating negative symptoms. Thus, interventions at GlyT1 are highly effective in modifying multiple brain functions, and dissection of their respective mechanisms is expected to further maximize their therapeutic potential for human mental diseases.

Keywords: Antipsychotic; Attention; Cognition; Learning; NMDA

The neurochemical basis for the treatment of autism spectrum disorders and Fragile X Syndrome by David R. Hampson; Daniel C. Adusei; Laura K.K. Pacey (pp. 1078-1086).

Autism spectrum disorders (ASD) and Fragile X Syndrome (FXS) are neurodevelopmental disorders that share overlapping behavioral characteristics. While FXS is known to result from a specific genetic mutation, the causes of the majority of cases of ASD are unknown. Animal models of FXS have revealed new insight into the cellular and biochemical changes that occur in the central nervous system in this disorder, while human genetic studies on individuals with autism have identified sets of genes that may increase susceptibility to the disorder. Together these discoveries suggest overlapping biochemical characteristics and reveal new directions for the potential development of pharmacological therapies that might prove useful in the treatment of both FXS and ASD. In particular, delayed synaptic maturation, abnormal synaptic structure and/or function and alterations in intracellular signaling pathways have been linked to the pathogenesis of FXS and ASD. Aberrations in GABA_A receptor ion channels and the G-protein coupled metabotropic glutamate and GABA_B transmitter systems are also linked to both disorders and these receptors are currently at the forefront of preclinical and clinical research into treatments for both autism and Fragile X Syndrome.

Keywords: Cerebellum; GABA; GABA(A); GABA(B); GTPase; Metabotropic glutamate; mGluR5; Neurodevelopmental; Dendritic spines

EGR1 expression: A calcium and ERK1/2 mediated PPAR_γ-independent event involved in the antiproliferative effect of 15-deoxy-Δ12,14-prostaglandin J2 and thiazolidinediones in breast cancer cells by Sarra Chbicheb; Xiao Yao; Jean-Luc Rodeau; Stéphane Salamone; Michel Boisbrun; Gerald Thiel; Daniel Spohn; Isabelle Grillier-Vuissoz; Yves Chapleur; Stéphane Flament; Sabine Mazerbourg (pp. 1087-1097).

Troglitazone (TGZ) and Δ2-TGZ induce an increase in cytosolic calcium leading to ERK1/2 phosphorylation and EGR1 expression in breast cancer cells, leading to growth inhibition. This event is independent of PPARγ and EGFR activation.Our aim was to get new information about the Peroxisome Proliferator Activated Receptor gamma (PPARγ)-independent pathway involved in the antiproliferative action of PPARγ ligands in breast cancer cells. We investigated the effects of Troglitazone (TGZ), Ciglitazone (CGZ), Rosiglitazone (RGZ) and, 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ₂) on the hormone-dependent breast cancer cell line MCF7. The early transcription factor EGR1 (Early Growth Response gene 1) mRNA and protein levels peaked after 3h of incubation with 25μM TGZ, CGZ or 15d-PGJ₂ and then gradually decreased. RGZ, the most potent activator of PPARγ, did not show this effect. The PPARγ antagonist GW 9662 did not block EGR1 mRNA induction which also still occurred in case of PPARγ silencing as well as in case of treatment with the PPARγ-inactive compound Δ2-TGZ. EGR1 mRNA induction required ERK1/2 phosphorylation which was not blocked by EGF Receptor (EGFR) inhibition. The ERK1/2 pathway was also involved in Δ2-TGZ-induced EGR1 mRNA expression in the hormone-independent breast cancer cell line MDA-MB-231. Using the fluorescent dye Fura2, we showed in MCF7 that TGZ or Δ2-TGZ induced an immediate increase in cytosolic calcium which was required for ERK1/2 phosphorylation and EGR1 mRNA induction as demonstrated by calcium chelation experiments. Furthermore, in MCF7 transfected with siRNA targeting EGR1, Δ2-TGZ inhibited less efficiently cell proliferation.

Keywords: Abbreviations; PPAR; peroxisome proliferator-activated receptor; EGR1; Early Growth Response gene 1; 15d-PGJ; ₂; 15-deoxy-(12,14-prostaglandin J2; TGZ; Troglitazone; CGZ; Ciglitazone; RGZ; Rosiglitazone; EGFR; EGF Receptor; NAB; NGFI-A-binding protein; FCS; fetal calf serum; DMSO; dimethylsulfoxide; DMEM; Dulbecco's modified Eagle's medium; dNTP; deoxynucleotide triphosphate; DTT; dithiothreitol; Ig; Immunoglobulin; MAPK; mitogen activated protein kinase; RPLPO; acidic ribosomal phosphoprotein POThiazolidinedione; Troglitazone; EGR1; Calcium signaling; Breast cancer

Small molecule inhibitors of peptidoglycan synthesis targeting the lipid II precursor by Adeline Derouaux; Samo Turk; Nick K. Olrichs; Stanislav Gobec; Eefjan Breukink; Ana Amoroso; Julien Offant; Julieanne Bostock; Katherine Mariner; Ian Chopra; Thierry Vernet; Astrid Zervosen; Bernard Joris; Jean-Marie Frère; Martine Nguyen-Distèche; Mohammed Terrak (pp. 1098-1105).

Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and represents a validated target for the development of new antibacterials. Application of structure-based virtual screening to the National Cancer Institute library using eHits program and the structure of the glycosyltransferase domain of the Staphylococcus aureus penicillin-binding protein 2 resulted in the identification of two small molecules analogues 5, a 2-[1-[(2-chlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine and 5b, a 2-[1-[(3,4-dichlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine that exhibit antibacterial activity against several Gram-positive bacteria but were less active on Gram-negative bacteria. The two compounds inhibit the activity of five GTs in the micromolar range. Investigation of the mechanism of action shows that the compounds specifically target peptidoglycan synthesis. Unexpectedly, despite the fact that the compounds were predicted to bind to the GT active site, compound 5b was found to interact with the lipid II substrate via the pyrophosphate motif. In addition, this compound showed a negatively charged phospholipid-dependent membrane depolarization and disruption activity. These small molecules are promising leads for the development of more active and specific compounds to target the essential GT step in cell wall synthesis.

Keywords: Abbreviations; PBP; penicillin-binding protein; GT; glycosyltransferase; PG; peptidoglycan; CF; carboxyfluorescein; DOPC; 1,2-dioleoyl-; sn; -glycero-3-phosphocholine; DOPG; 1,2-dioleoyl-; sn; -glycero-3-[phospho-; rac; -(1-glycerol)]; 11-PP; undecaprenylpyrophosphate; 11-P; undecaprenylphosphate; LUV; large unilamellar vesicleGlycosyltransferase; Peptidoglycan; Antibacterial; Lipid II; Penicillin-binding protein

Effects of AZD1152, a selective Aurora B kinase inhibitor, on Burkitt's and Hodgkin's lymphomas by Naoki Mori; Chie Ishikawa; Masachika Senba; Masashi Kimura; Yukio Okano (pp. 1106-1115).

We studied the effects of AZD1152, an Aurora B kinase inhibitor, on Burkitt's lymphoma (BL) and Hodgkin's lymphoma (HL) in human tissues and cell cultures and in a murine xenograft model of lymphoma. Aurora kinase A and B levels were assessed by RT-PCR and immunohistochemistry. They were aberrantly expressed in BL and HL cell lines, and in lymph nodes from patients with BL and HL. Next, activation of the Aurora B promoter was detected by reporter gene assays. The promoter activity of Aurora B kinase was high in BL cell lines and the Aurora B promoter contained a positive regulatory region between −74 and −104 from the transcription initiation site. AZD1152-hQPA had antiproliferative effects in the BL and HL cell lines studied; inhibited the phosphorylation of histone H3 and retinoblastoma proteins, and resulted in cells with >4N DNA content. AZD1152-hQPA induced caspase-dependent apoptosis of some cell lines, demonstrated by loss of mitochondrial membrane potential, activation of caspase-9, followed by activation of caspase-3. This effect was accompanied by the inhibition of survivin expression. In vivo efficacy was determined in NOD/SCID/γc^null mice implanted with the Ramos human BL cell line. AZD1152 had anti-tumour effects in this murine xenograft model. There preclinical data suggest that the inhibition of Aurora B kinase is a potentially useful therapeutic strategy in BL and HL.

Keywords: Aurora B; AZD1152; Burkitt's lymphoma; Hodgkin's lymphoma; Apoptosis

Intramolecular cyclization of N-phenyl N′(2-chloroethyl)ureas leads to active N-phenyl-4,5-dihydrooxazol-2-amines alkylating β-tubulin Glu198 and prohibitin Asp40 by Anna Trzeciakiewicz; Sébastien Fortin; Emmanuel Moreau; René C.-Gaudreault; Jacques Lacroix; Christophe Chambon; Yves Communal; Jean-Michel Chezal; Elisabeth Miot-Noirault; Bernadette Bouchon; Françoise Degoul (pp. 1116-1123).

The cyclization of anticancer drugs into active intermediates has been reported mainly for DNA alkylating molecules including nitrosoureas. We previously defined the original cytotoxic mechanism of anticancerous N-phenyl- N′-(2-chloroethyl)ureas (CEUs) that involves their reactivity towards cellular proteins and not against DNA; two CEU subsets have been shown to alkylate β-tubulin and prohibitin leading to inhibition of cell proliferation by G₂/M or G₁/S cell cycle arrest. In this study, we demonstrated that cyclic derivatives of CEUs, N-phenyl-4,5-dihydrooxazol-2-amines (Oxas) are two- to threefold more active than CEUs and share the same cytotoxic properties in B16F0 melanoma cells. Moreover, the CEU original covalent binding by an ester linkage on β-tubulin Glu198 and prohibitin Asp40 was maintained with Oxas. Surprisingly, we observed that Oxas were spontaneously formed from CEUs in the cell culture medium and were also detected within the cells. Our results suggest that the intramolecular cyclization of CEUs leads to active Oxas that should then be considered as the key intermediates for protein alkylation. These results will be useful for the design of new prodrugs for cancer chemotherapy.

Keywords: N; -Phenyl-; N; ′-(2-chloroethyl)ureas; N; -Phenyl-4,5-dihydrooxazol-2-amines; β-Tubulin; Prohibitin; Alkylation; Cyclization

Acetaminophen-induced differentiation of human breast cancer stem cells and inhibition of tumor xenograft growth in mice by Masaya Takehara; Tatsuya Hoshino; Takushi Namba; Naoki Yamakawa; Tohru Mizushima (pp. 1124-1135).

We searched for drugs that induced a morphological change in breast cancer stem cell-like cells, and found that acetaminophen induces the morphological change through their differentiation.It is now believed that cancer stem cells (CSCs) that are resistant to chemotherapy due to their undifferentiated nature drive tumor growth, metastasis and relapse, so development of drugs that induce differentiation of CSCs should have a profound impact on cancer eradication. In this study, we screened medicines that are already in clinical use for drugs that induce differentiation of CSCs. We used MDA-MB-231, a human breast cancer cell line that contains cancer stem cell-like cells. We found that acetaminophen, an anti-inflammatory, antipyretic and analgesic drug, induces differentiation of MDA-MB-231 cells. Differentiation was assessed by observing alterations in cell shape and expression of differentiated and undifferentiated cell markers, a decrease in cell invasion activity and an increase in susceptibility to anti-tumor drugs. This increased susceptibility seems to involve suppression of expression of multidrug efflux pumps. We also suggest that this induction of differentiation is mediated by inhibition of a Wnt/β-catenin canonical signaling pathway. Treatment of MDA-MB-231 cells with acetaminophen in vitro resulted in the loss of their tumorigenic ability in nude mice. Furthermore, administration of acetaminophen inhibited the growth of tumor xenografts of MDA-MB-231 cells in both the presence and absence of simultaneous administration of doxorubicine, a typical anti-tumor drug for breast cancer. Analysis with various acetaminophen derivatives revealed that o-acetamidophenol has a similar differentiation-inducing activity and a similar inhibitory effect on tumor xenograft growth. These results suggest that acetaminophen may be beneficial for breast cancer chemotherapy by inducing the differentiation of CSCs.

Keywords: Cancer stem cells; Differentiation; Acetaminophen; Anti-cancer drug

A unique P-glycoprotein interacting agent displays anticancer activity against hepatocellular carcinoma through inhibition of GRP78 and mTOR pathways by Ting-Chun Kuo; Po-Cheng Chiang; Chia-Chun Yu; Kyoko Nakagawa-Goto; Kenneth F. Bastow; Kuo-Hsiung Lee; Jih-Hwa Guh (pp. 1136-1144).

P-glycoprotein (P-gp) overexpression has been demonstrated in many malignancies being a predominant mechanism by which cancer cells develop multidrug resistance. Several categories of P-gp inhibitors have been demonstrated to potentiate anticancer effect induced by cancer chemotherapeutic drugs through competitive inhibition of P-gp pumping activity. Few studies show the agent that selectively acts on P-gp and, by itself, causes cell apoptosis while remain P-gp-deficient cells unaffected. KNG-I-322, a desmosdumotin B derivative, displayed a direct interaction with P-gp and demonstrated selective anti-proliferative and apoptotic activities in P-gp overexpressed Hep3B/VIN other than P-gp-deficient Hep3B cells. KNG-I-322 induced an inhibitory effect on the phosphorylation of mTOR^Ser2448, p70S6K^Thr389 and 4E-BP^Thr37/46 in Hep3B/VIN but not Hep3B cells. The inhibition was fully blocked by the knockdown of P-gp using siRNA techniques. Notably, the P-gp inhibitor, verapamil, also directly interacted with P-gp but significantly diminished KNG-I-322-induced anti-proliferative activity. After the mechanism study, the data showed that KNG-I-322 induced a dramatic down-regulation of GRP78 expression, which was significantly inhibited by verapamil and completely diminished by the knockdown of P-gp. The protein profile analysis of detergent resistant membranes showed that upon the stimulation by KNG-I-322, the level of P-gp expression in non-raft fractions was dramatically increased and, concomitantly, the GRP78 expression was significantly decreased. Taken together, the data suggest that KNG-I-322 induces anticancer activity in Hep3B/VIN cells through a direct interaction with P-gp, leading to the inhibition of mTOR pathways and the induction of GRP78 down-regulation. The data support that KNG-I-322 is a selective anticancer agent against P-gp-overexpressed other than P-gp-deficient cancer cells.

Keywords: P-glycoprotein; Multidrug resistance; ATPase activity; mTOR pathways; GRP78

A comparative study on the modes of action of TAK-438, a novel potassium-competitive acid blocker, and lansoprazole in primary cultured rabbit gastric glands by Jun Matsukawa; Yasunobu Hori; Haruyuki Nishida; Masahiro Kajino; Nobuhiro Inatomi (pp. 1145-1151).

TAK-438 is a novel potassium-competitive acid blocker (P-CAB) type antisecretory agent that reversibly inhibits gastric H⁺, K⁺-ATPase. Previously, we showed that TAK-438 has superior efficacy compared to lansoprazole, a proton pump inhibitor, in the inhibition of acid secretion in vivo. In this study, we investigated the differences in the mode of actions of the two drugs using primary cultured rabbit gastric glands. TAK-438 and lansoprazole inhibited gastric acid formation in acutely isolated gastric glands (IC₅₀ values, 0.30 and 0.76μM, respectively). In cultured gastric glands that were preincubated with TAK-438, the inhibitory effect on forskolin-stimulated acid formation was augmented over the incubation period, whereas the inhibitory effect of lansoprazole was not affected by time of incubation. Next, we evaluated the durations of the actions of TAK-438 and lansoprazole after gastric glands were incubated with either drug for 2h followed by washout. Even 8h after the drug washout, TAK-438 at higher concentrations inhibited acid formation, but the inhibitory effect of lansoprazole disappeared immediately after washout. Additionally, only a small amount of [¹⁴C] lansoprazole accumulated in resting glands, and this accumulation was enhanced by treatment with 1μM of forskolin. In contrast, high levels of [¹⁴C] TAK-438 accumulated in both resting and forskolin-treated glands. Furthermore, a 2-h preincubation followed by washout demonstrated a slow clearance of [¹⁴C] TAK-438 from the glands. These findings suggest that TAK-438 exerts a longer and more potent antisecretory effect than lansoprazole as a result of its high accumulation and slow clearance from the gastric glands.

Keywords: TAK-438; Lansoprazole; P-CAB; H; ⁺; , K; ⁺; -ATPase; Gastric glands

EGCG stimulates autophagy and reduces cytoplasmic HMGB1 levels in endotoxin-stimulated macrophages by Wei Li; Shu Zhu; Jianhua Li; Andrei Assa; Arvin Jundoria; Jianying Xu; Saijun Fan; N. Tony Eissa; Kevin J. Tracey; Andrew E. Sama; Haichao Wang (pp. 1152-1163).

Via oxidation, EGCG spontaneously forms aggregation products (e.g. theasinensin), which interact with HMGB1 to form EGCG–HMGB1 complexes. These complexes are engulfed into autophagosomes, and degraded in an autophagy-dependent mechanism.Historically, consumption of Green tea ( Camellia sinensis) has been associated with health benefits against multiple diseases including cancer, atherosclerosis and cardiovascular disorders. Emerging evidence has suggested a pathogenic role for HMGB1, a newly identified “late” mediator of lethal systemic inflammation, in the aforementioned diseases. Here we demonstrated that a major ingredient of Green tea, EGCG, was internalized into HMGB1-containing LC3-positive cytoplasmic vesicles (likely autophagosomes) in macrophages, and induced HMGB1 aggregation in a time-dependent manner. Furthermore, EGCG stimulated LC3-II production and autophagosome formation, and inhibited LPS-induced HMGB1 up-regulation and extracellular release. The EGCG-mediated HMGB1 inhibitory effects were diminished by inhibition of class III phosphatidylinositol-3 kinase (with 3-methyladenine) or knockdown of an essential autophagy-regulating protein, beclin-1. Moreover, the EGCG-mediated protection against lethal sepsis was partly impaired by co-administration of an autophagy inhibitor, chloroquine. Taken together, the present study has suggested a possibility that EGCG inhibits HMGB1 release by stimulating its autophagic degradation.

Keywords: Abbreviations; CLP; cecal ligation and puncture; EGCG; (−)-epigallocatechin-3-gallate; HMGB1; high mobility group box 1; LC3; microtubule-associated protein1 light chain 3; LPS; lipopolysaccharide

Vaccination against nicotine alters the distribution of nicotine delivered via cigarette smoke inhalation to rats by M. Pravetoni; D.E. Keyler; M.D. Raleigh; A.C. Harris; M.G. LeSage; C.K. Mattson; S. Pettersson; P.R. Pentel (pp. 1164-1170).

Distribution to brain of nicotine inhaled in cigarette smoke is reduced by vaccination against nicotine.Preclinical models of nicotine vaccine pharmacology have relied on i.v. or s.c. administration of nicotine. Models using cigarette smoke inhalation might more accurately simulate nicotine exposure in smokers. Nicotine vaccine effects were examined in rats using two cigarette smoke exposure models: a 10min nose-only exposure (NSE) producing serum nicotine levels equivalent to the nicotine boost from 1 cigarette in a smoker, and a 2h whole-body exposure (WBE) producing serum nicotine levels similar to those associated with regular mid-day smoking. Vaccination prior to 10min smoke NSE reduced nicotine distribution to brain by 90%, comparable to its effect on nicotine administered i.v. Vaccination prior to 2h smoke WBE reduced nicotine distribution to brain by 35%. The nicotine concentration in broncheoalveolar lavage (BAL) fluid obtained after 2h WBE was increased by 230% in vaccinated rats but was also increased in rats passively immunized with a nicotine-specific monoclonal antibody, and so was likely due to transfer of antibody from serum rather than local production at the pulmonary mucosa. Nicotine-specific IgA was not detectable in BAL fluid, but titers in serum were appreciable at 21–25% of the IgG titer and could contribute to vaccine efficacy. Both vaccination and passive immunization are effective in reducing nicotine distribution to brain in rats when nicotine is delivered via inhaled cigarette smoke. These data validate results previously obtained in rodents for nicotine vaccines using i.v. or s.c. nicotine dosing and provide a quantitative method for studying aspects of nicotine exposure which are unique to cigarette smoke inhalation.

Keywords: Nicotine; Smoke; Cigarette; Antibody; Immunotherapy; Vaccine; Immunogenicity

Sections

Personal tools

Biochemical Pharmacology (v.81, #9)

Sections

Personal tools

Local resources

Biochemical Pharmacology (v.81, #9)