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Sample records for kinase enhance prodrug

  1. Prodrugs of herpes simplex thymidine kinase inhibitors.

    Science.gov (United States)

    Yanachkova, Milka; Xu, Wei-Chu; Dvoskin, Sofya; Dix, Edward J; Yanachkov, Ivan B; Focher, Federico; Savi, Lida; Sanchez, M Dulfary; Foster, Timothy P; Wright, George E

    2015-04-01

    Because guanine-based herpes simplex virus thymidine kinase inhibitors are not orally available, we synthesized various 6-deoxy prodrugs of these compounds and evaluated them with regard to solubility in water, oral bioavailability, and efficacy to prevent herpes simplex virus-1 reactivation from latency in a mouse model. Organic synthesis was used to prepare compounds, High Performance Liquid Chromatography (HPLC) to analyze hydrolytic conversion, Mass Spectrometry (MS) to measure oral bioavailability, and mouse latent infection and induced reactivation to evaluate the efficacy of a specific prodrug. Aqueous solubilities of prodrugs were improved, oxidation of prodrugs by animal cytosols occurred in vitro, and oral absorption of the optimal prodrug sacrovir™ (6-deoxy-mCF3PG) in the presence of the aqueous adjuvant Soluplus® and conversion to active compound N(2)-[3-(trifluoromethyl)pheny])guanine (mCF3PG) were accomplished in mice. Treatment of herpes simplex virus-1 latent mice with sacrovir™ in 1% Soluplus in drinking water significantly suppressed herpes simplex virus-1 reactivation and viral genomic replication. Ad libitum oral delivery of sacrovir™ was effective in suppressing herpes simplex virus-1 reactivation in ocularly infected latent mice as measured by the numbers of mice shedding infectious virus at the ocular surface, numbers of trigeminal ganglia positive for infectious virus, number of corneas that had detectable infectious virus, and herpes simplex virus-1 genome copy numbers in trigeminal ganglia following reactivation. These results demonstrate the statistically significant effect of the prodrug on suppressing herpes simplex virus-1 reactivation in vivo. © The Author(s) 2015.

  2. Photoactivatable Caged Prodrugs of VEGFR-2 Kinase Inhibitors

    OpenAIRE

    Boris Pinchuk; Rebecca Horbert; Alexander Döbber; Lydia Kuhl; Christian Peifer

    2016-01-01

    In this study, we report on the design, synthesis, photokinetic properties and in vitro evaluation of photoactivatable caged prodrugs for the receptor tyrosine kinase VEGFR-2. Highly potent VEGFR-2 inhibitors 1 and 3 were caged by introduction of a photoremovable protecting group (PPG) to yield the caged prodrugs 4 and 5. As expected, enzymatic and cellular proliferation assays showed dramatically diminished efficacy of caged prodrugs in vitro. Upon ultraviolet (UV) irradiation of the prodrug...

  3. Photoactivatable Caged Prodrugs of VEGFR-2 Kinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Boris Pinchuk

    2016-04-01

    Full Text Available In this study, we report on the design, synthesis, photokinetic properties and in vitro evaluation of photoactivatable caged prodrugs for the receptor tyrosine kinase VEGFR-2. Highly potent VEGFR-2 inhibitors 1 and 3 were caged by introduction of a photoremovable protecting group (PPG to yield the caged prodrugs 4 and 5. As expected, enzymatic and cellular proliferation assays showed dramatically diminished efficacy of caged prodrugs in vitro. Upon ultraviolet (UV irradiation of the prodrugs original inhibitory activity was completely restored and even distinctly reinforced, as was the case for the prodrug 4. The presented results are a further evidence for caging technique being an interesting approach in the protein kinase field. It could enable spatial and temporal control for the inhibition of VEGFR-2. The described photoactivatable prodrugs might be highly useful as biological probes for studying the VEGFR-2 signal transduction.

  4. Evaluation of diclofenac prodrugs for enhancing transdermal delivery.

    Science.gov (United States)

    Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

    2014-03-01

    Abstract Objective: The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD) and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in the Franz diffusion cell were determined on DA-, MD-, ED-, GD- and PD-saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery.

  5. Evaluation of Diclofenac Prodrugs for Enhancing Transdermal Delivery

    Science.gov (United States)

    Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

    2016-01-01

    The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD), and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates, and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in Franz diffusion cell were determined on DA, MD, ED, GD, and PD saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Overall, diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery. PMID:24517636

  6. Evaluation of Diclofenac Prodrugs for Enhancing Transdermal Delivery

    OpenAIRE

    Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

    2013-01-01

    The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD), and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates, and bioconversion rates. ...

  7. Slow self-activation enhances the potency of viridin prodrugs.

    Science.gov (United States)

    Blois, Joseph; Yuan, Hushan; Smith, Adam; Pacold, Michael E; Weissleder, Ralph; Cantley, Lewis C; Josephson, Lee

    2008-08-14

    When the viridin wortmannin (Wm) is modified by reaction with certain nucleophiles at the C20 position, the compounds obtained exhibit an improved antiproliferative activity even though a covalent reaction between C20 and a lysine in the active site of PI3 kinase is essential to Wm's ability to inhibit this enzyme. Here we show that this improved potency results from an intramolecular attack by the C6 hydroxyl group that slowly converts these inactive prodrugs to the active species Wm over the 48 h duration of the antiproliferative assay. Our results provide a guide for selecting Wm-like compounds to maximize kinase inhibition with the variety of protocols used to assess the role of PI3 kinase in biological systems, or for achieving optimal therapeutic effects in vivo . In addition, the slow self-activation of WmC20 derivatives provides a mechanism that can be exploited to obtain kinase inhibitors endowed with physical and pharmacokinetic properties far different from man-made kinase inhibitors because they do not bind to kinase active sites.

  8. Dominant negative selection of vaccinia virus using a thymidine kinase/thymidylate kinase fusion gene and the prodrug azidothymidine

    International Nuclear Information System (INIS)

    Holzer, Georg W.; Mayrhofer, Josef; Gritschenberger, Werner; Falkner, Falko G.

    2005-01-01

    The Escherichia coli thymidine kinase/thymidylate kinase (tk/tmk) fusion gene encodes an enzyme that efficiently converts the prodrug 3'-azido-2',3'-dideoxythymidine (AZT) into its toxic triphosphate derivative, a substance which stops DNA chain elongation. Integration of this marker gene into vaccinia virus that normally is not inhibited by AZT allowed the establishment of a powerful selection procedure for recombinant viruses. In contrast to the conventional vaccinia thymidine kinase (tk) selection that is performed in tk-negative cell lines, AZT selection can be performed in normal (tk-positive) cell lines. The technique is especially useful for the generation of replication-deficient vaccinia viruses and may also be used for gene knock-out studies of essential vaccinia genes

  9. Enhancing the intestinal membrane permeability of zanamivir: a carrier mediated prodrug approach.

    Science.gov (United States)

    Gupta, Sheeba Varghese; Gupta, Deepak; Sun, Jing; Dahan, Arik; Tsume, Yasuhiro; Hilfinger, John; Lee, Kyung-Dall; Amidon, Gordon L

    2011-12-05

    The purpose of this study was to improve the membrane permeability and oral absorption of the poorly permeable anti-influenza agent, zanamivir. The poor oral bioavailability is attributed to the high polarity (cLogP ∼ -5) resulting from the polar and zwitterionic nature of zanamivir. In order to improve the permeability of zanamivir, prodrugs with amino acids were developed to target the intestinal membrane transporter, hPepT1. Several acyloxy ester prodrugs of zanamivir conjugated with amino acids were synthesized and characterized. The prodrugs were evaluated for their chemical stability in buffers at various pHs and for their transport and tissue activation by enzymes. The acyloxy ester prodrugs of zanamivir were shown to competitively inhibit [(3)H]Gly-Sar uptake in Caco-2 cells (IC(50): 1.19 ± 0.33 mM for L-valyl prodrug of zanamivir). The L-valyl prodrug of zanamivir exhibited ∼3-fold higher uptake in transfected HeLa/hPepT1 cells compared to wild type HeLa cells, suggesting, at least in part, carrier mediated transport by the hPepT1 transporter. Further, enhanced transcellular permeability of prodrugs across Caco-2 monolayer compared to the parent drug (P(app) = 2.24 × 10(-6) ± 1.33 × 10(-7) cm/s for L-valyl prodrug of zanamivir), with only parent zanamivir appearing in the receiver compartment, indicates that the prodrugs exhibited both enhanced transport and activation in intestinal mucosal cells. Most significantly, several of these prodrugs exhibited high intestinal jejunal membrane permeability, similar to metoprolol, in the in situ rat intestinal perfusion system, a system highly correlated with human jejunal permeability. In summary, this mechanistic targeted prodrug strategy, to enhance oral absorption via intestinal membrane carriers such as hPepT1, followed by activation to parent drug (active pharmaceutical ingredient or API) in the mucosal cell, significantly improves the intestinal epithelial cell permeability of zanamivir and has the

  10. Transdermal Delivery and Cutaneous Targeting of Antivirals using a Penetration Enhancer and Lysolipid Prodrugs

    Czech Academy of Sciences Publication Activity Database

    Diblíková, D.; Kopečná, M.; Školová, B.; Krečmerová, Marcela; Roh, J.; Hrabálek, A.; Vávrová, K.

    2014-01-01

    Roč. 31, č. 4 (2014), s. 1071-1081 ISSN 0724-8741 Grant - others:GA ČR(CZ) GAP207/11/0365 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonate antivirals * lysolipid prodrug * penetration enhancer * skin absorption * transdermal drug delivery Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 3.420, year: 2014

  11. The development of orally administrable gemcitabine prodrugs with D-enantiomer amino acids: enhanced membrane permeability and enzymatic stability.

    Science.gov (United States)

    Tsume, Yasuhiro; Incecayir, Tuba; Song, Xueqin; Hilfinger, John M; Amidon, Gordon L

    2014-04-01

    Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3-17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2-10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of d-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gemcitabine prodrugs. In general, the 5'-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5'-D-valyl-gemcitabine and 5'-D-phenylalanyl-gemcitabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients. Copyright © 2014. Published by Elsevier B.V.

  12. Transdermal delivery and cutaneous targeting of antivirals using a penetration enhancer and lysolipid prodrugs.

    Science.gov (United States)

    Diblíková, Denisa; Kopečná, Monika; Školová, Barbora; Krečmerová, Marcela; Roh, Jaroslav; Hrabálek, Alexandr; Vávrová, Kateřina

    2014-04-01

    In this work, we investigate prodrug and enhancer approaches for transdermal and topical delivery of antiviral drugs belonging to the 2,6-diaminopurine acyclic nucleoside phosphonate (ANP) group. Our question was whether we can differentiate between transdermal and topical delivery, i.e., to control the delivery of a given drug towards either systemic absorption or retention in the skin. The in vitro transdermal delivery and skin concentrations of seven antivirals, including (R)- and (S)-9-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine (PMPDAP), (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine ((S)-HPMPDAP), its 8-aza analog, and their cyclic and hexadecyloxypropyl (HDP) prodrugs, was investigated with and without the penetration enhancer dodecyl-6-(dimethylamino)hexanoate (DDAK) using human skin. The ability of ANPs to cross the human skin barrier was very low (0.5-1.4 nmol/cm(2)/h), and the majority of the compounds were found in the stratum corneum, the uppermost skin layer. The combination of antivirals and the penetration enhancer DDAK proved to be a viable approach for transdermal delivery, especially in case of (R)-PMPDAP, an anti-HIV effective drug (30.2 ± 2.3 nmol/cm(2)/h). On the other hand, lysophospholipid-like HDP prodrugs, e.g., HDP-(S)-HPMPDAP, reached high concentrations in viable epidermis without significant systemic absorption. By using penetration enhancers or lysolipid prodrugs, it is possible to effectively target systemic diseases by the transdermal route or to target cutaneous pathologies by topical delivery.

  13. Identification of a Potent Phosphoinositide 3-Kinase Pan Inhibitor Displaying a Strategic Carboxylic Acid Group and Development of Its Prodrugs.

    Science.gov (United States)

    Pirali, Tracey; Ciraolo, Elisa; Aprile, Silvio; Massarotti, Alberto; Berndt, Alex; Griglio, Alessia; Serafini, Marta; Mercalli, Valentina; Landoni, Clarissa; Campa, Carlo Cosimo; Margaria, Jean Piero; Silva, Rangel L; Grosa, Giorgio; Sorba, Giovanni; Williams, Roger; Hirsch, Emilio; Tron, Gian Cesare

    2017-09-21

    Activation of the phosphoinositide 3-kinase (PI3K) pathway is a key signaling event in cancer, inflammation, and other proliferative diseases. PI3K inhibitors are already approved for some specific clinical indications, but their systemic on-target toxicity limits their larger use. In particular, whereas toxicity is tolerable in acute treatment of life-threatening diseases, this is less acceptable in chronic conditions. In the past, the strategy to overcome this drawback was to block selected isoforms mainly expressed in leukocytes, but redundancy within the PI3K family members challenges the effectiveness of this approach. On the other hand, decreasing exposure to selected target cells represents a so-far unexplored alternative to circumvent systemic toxicity. In this manuscript, we describe the generation of a library of triazolylquinolones and the development of the first prodrug pan-PI3K inhibitor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Enhanced Absorption and Growth Inhibition with Amino Acid Monoester Prodrugs of Floxuridine by Targeting hPEPT1 Transporters

    Directory of Open Access Journals (Sweden)

    Gordon L. Amidon

    2008-06-01

    Full Text Available A series of amino acid monoester prodrugs of floxuridine was synthesized and evaluated for the improvement of oral bioavailability and the feasibility of target drug delivery via oligopeptide transporters. All floxuridine 5′-amino acid monoester prodrugs exhibited PEPT1 affinity, with inhibition coefficients of Gly-Sar uptake (IC50 ranging from 0.7 – 2.3 mM in Caco-2 and 2.0 – 4.8 mM in AsPC-1 cells, while that of floxuridine was 7.3 mM and 6.3 mM, respectively. Caco-2 membrane permeabilities of floxuridine prodrugs (1.01 – 5.31 x 10-6 cm/sec and floxuridine (0.48 x 10-6 cm/sec were much higher than that of 5-FU (0.038 x 10-6 cm/sec. MDCK cells stably transfected with the human oligopeptide transporter PEPT1 (MDCK/hPEPT1 exhibited enhanced cell growth inhibition in the presence of the prodrugs. This prodrug strategy offers great potential, not only for increased drug absorption but also for improved tumor selectivity and drug efficacy.

  15. Enhanced absorption and growth inhibition with amino acid monoester prodrugs of floxuridine by targeting hPEPT1 transporters.

    Science.gov (United States)

    Tsume, Yasuhiro; Vig, Balvinder S; Sun, Jing; Landowski, Christopher P; Hilfinger, John M; Ramachandran, Chandrasekharan; Amidon, Gordon L

    2008-06-28

    A series of amino acid monoester prodrugs of floxuridine was synthesized and evaluated for the improvement of oral bioavailability and the feasibility of target drug delivery via oligopeptide transporters. All floxuridine 5'-amino acid monoester prodrugs exhibited PEPT1 affinity, with inhibition coefficients of Gly-Sar uptake (IC50) ranging from 0.7 - 2.3 mM in Caco-2 and 2.0 - 4.8 mM in AsPC-1 cells, while that of floxuridine was 7.3 mM and 6.3 mM, respectively. Caco-2 membrane permeabilities of floxuridine prodrugs (1.01 - 5.31 x 10(-6 )cm/sec) and floxuridine (0.48 x 10(-6 )cm/sec) were much higher than that of 5-FU (0.038 x 10(-6) cm/sec). MDCK cells stably transfected with the human oligopeptide transporter PEPT1 (MDCK/hPEPT1) exhibited enhanced cell growth inhibition in the presence of the prodrugs. This prodrug strategy offers great potential, not only for increased drug absorption but also for improved tumor selectivity and drug efficacy.

  16. Enhancement of hypoxia-activated prodrug TH-302 anti-tumor activity by Chk1 inhibition.

    Science.gov (United States)

    Meng, Fanying; Bhupathi, Deepthi; Sun, Jessica D; Liu, Qian; Ahluwalia, Dharmendra; Wang, Yan; Matteucci, Mark D; Hart, Charles P

    2015-05-21

    The hypoxia-activated prodrug TH-302 is reduced at its nitroimidazole group and selectively under hypoxic conditions releases the DNA cross-linker bromo-isophosphoramide mustard (Br-IPM). Here, we have explored the effect of Chk1 inhibition on TH-302-mediated pharmacological activities. We employed in vitro cell viability, DNA damage, cellular signaling assays and the in vivo HT29 human tumor xenograft model to study the effect of Chk1inhibition on TH-302 antitumor activities. TH-302 cytotoxicity is greatly enhanced by Chk1 inhibition in p53-deficient but not in p53-proficient human cancer cell lines. Chk1 inhibitors reduced TH-302-induced cell cycle arrest via blocking TH-302-induced decrease of phosphorylation of histone H3 and increasing Cdc2-Y15 phosphorylation. Employing the single-cell gel electrophoresis (comet) assay, we observed a potentiation of the TH-302 dependent tail moment. TH-302 induced γH2AX and apoptosis were also increased upon the addition of Chk1 inhibitor. Potentiation of TH-302 cytotoxicity by Chk1 inhibitor was only observed in cell lines proficient in, but not deficient in homology-directed DNA repair. We also show that combination treatment led to lowering of Rad51 expression levels as compared to either agent alone. In vivo data demonstrate that Chk1 inhibitor enhances TH-302 anti-tumor activity in p53 mutant HT-29 human tumor xenografts, supporting the hypothesis that these in vitro results can translate to enhanced in vivo efficacy of the combination. TH-302-mediated in vitro and in vivo anti-tumor activities were greatly enhanced by the addition of Chk1 inhibitors. The preclinical data presented in this study support a new approach for the treatment of p53-deficient hypoxic cancers by combining Chk1 inhibitors with the hypoxia-activated prodrug TH-302.

  17. Prodrugs in Cardiovascular Therapy

    Directory of Open Access Journals (Sweden)

    Maryam Tabrizian

    2008-05-01

    Full Text Available Prodrugs are biologically inactive derivatives of an active drug intended to solve certain problems of the parent drug such as toxicity, instability, minimal solubility and non-targeting capabilities. The majority of drugs for cardiovascular diseases undergo firstpass metabolism, resulting in drug inactivation and generation of toxic metabolites, which makes them appealing targets for prodrug design. Since prodrugs undergo a chemical reaction to form the parent drug once inside the body, this makes them very effective in controlling the release of a variety of compounds to the targeted site. This review will provide the reader with an insight on the latest developments of prodrugs that are available for treating a variety of cardiovascular diseases. In addition, we will focus on several drug delivery methodologies that have merged with the prodrug approach to provide enhanced target specificity and controlled drug release with minimal side effects.

  18. Design of cellulose ether-based macromolecular prodrugs of ciprofloxacin for extended release and enhanced bioavailability.

    Science.gov (United States)

    Amin, Muhammad; Abbas, Nazia Shahana; Hussain, Muhammad Ajaz; Sher, Muhammad; Edgar, Kevin J

    2018-07-01

    The present study reveals the syntheses of hydroxypropylcellulose‑(HPC) and hydroxyethylcellulose‑(HEC) based macromolecular prodrugs (MPDs) of ciprofloxacin (CIP) using homogeneous reaction methodology. Covalently loaded drug content (DC) of each prodrug was quantified using UV-Vis spectrophotometry to determine degree of substitution (DS). HPC-ciprofloxacin (HPC-CIP) conjugates showed DS of CIP in the range 0.87-1.15 whereas HEC-ciprofloxacin (HEC-CIP) conjugates showed DS range 0.51-0.75. Transmission electron microscopy revealed that HPC-CIP conjugate 2 and HEC-CIP conjugate 6 self-assembled into nanoparticles of 150-300 and 180-250nm, respectively. Size exclusion chromatography revealed HPC-CIP conjugate 2 and HEC-CIP conjugate 6 as monodisperse systems. In vitro drug release studies indicated 15 and 43% CIP release from HPC-CIP conjugate 2 after 6h in simulated gastric and simulated intestinal fluids (SGF and SIF), respectively. HEC-CIP conjugate 6 showed 16% and 46% release after 6h in SGF and SIF, respectively. HPC-CIP conjugate 2 and HEC-CIP conjugate 6 exhibited half-lives of 10.87 and 11.71h, respectively with area under the curve values of 164 and 175hμgmL -1 , respectively, indicating enhanced bioavailability and improved pharmacokinetic profiles in animal model. Equal antibacterial activities to that of unmodified CIP confirmed their competitive efficacies. Cytotoxicity studies supported their non-toxic nature and biocompatibility. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Comparison of two self-assembled macromolecular prodrug micelles with different conjugate positions of SN38 for enhancing antitumor activity

    Directory of Open Access Journals (Sweden)

    Liu Y

    2015-03-01

    Full Text Available Yi Liu,1 Hongyu Piao,1 Ying Gao,1 Caihong Xu,2 Ye Tian,1 Lihong Wang,1 Jinwen Liu,1 Bo Tang,1 Meijuan Zou,1 Gang Cheng1 1Department of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, People’s Republic of China; 2Department of Food Science, Shenyang Normal University, Shenyang, Liaoning Province, People’s Republic of China Abstract: 7-Ethyl-10-hydroxycamptothecin (SN38, an active metabolite of irinotecan (CPT-11, is a remarkably potent antitumor agent. The clinical application of SN38 has been extremely restricted by its insolubility in water. In this study, we successfully synthesized two macromolecular prodrugs of SN38 with different conjugate positions (chitosan-(C10-OHSN38 and chitosan-(C20-OHSN38 to improve the water solubility and antitumor activity of SN38. These prodrugs can self-assemble into micelles in aqueous medium. The particle size, morphology, zeta potential, and in vitro drug release of SN38 and its derivatives, as well as their cytotoxicity, pharmacokinetics, and in vivo antitumor activity in a xenograft BALB/c mouse model were studied. In vitro, chitosan-(C10-OHSN38 (CS-(10sSN38 and chitosan-(C20-OHSN38 (CS-(20sSN38 were 13.3- and 25.9-fold more potent than CPT-11 in the murine colon adenocarcinoma cell line CT26, respectively. The area under the curve (AUC0–24 of SN38 after intravenously administering CS-(10sSN38 and CS-(20sSN38 to Sprague Dawley rats was greatly improved when compared with CPT-11 (both P<0.01. A larger AUC0–24 of CS-(20sSN38 was observed when compared to CS-(10sSN38 (P<0.05. Both of the novel self-assembled chitosan-SN38 prodrugs demonstrated superior anticancer activity to CPT-11 in the CT26 xenograft BALB/c mouse model. We have also investigated the differences between these macromolecular prodrug micelles with regards to enhancing the antitumor activity of SN38. CS-(20sSN38 exhibited better in vivo antitumor activity than CS-(10sSN38 at a dose of 2.5 mg/kg (P<0

  20. Enhancement of Curcumin Bioavailability Via the Prodrug Approach: Challenges and Prospects.

    Science.gov (United States)

    Ratnatilaka Na Bhuket, Pahweenvaj; El-Magboub, Asma; Haworth, Ian S; Rojsitthisak, Pornchai

    2017-06-01

    Curcumin is a natural product with many interesting pharmacological properties. However, these are offset by the particularly poor biopharmaceutical properties. The oral bioavailability of curcumin in humans is very low, mainly due to low solubility, poor stability, and extensive metabolism. This has led to multiple approaches to improve bioavailability, including administration of curcumin with metabolism inhibitors, formulation into nanoparticles, modification of the curcumin structure, and development of curcumin prodrugs. In this paper, we focus on the pharmacokinetic outcomes of these approaches. Pharmacokinetic parameters of curcumin after release from prodrugs are dependent on the linker between curcumin and the promoiety, and the release itself may depend on the physiological and enzymatic environment at the site of cleavage. This is an area in which more data are required for rational design of improved linkers. Cytotoxicity of curcumin prodrugs seems to correlate well with cellular uptake in vitro, but the in vivo relevance is uncertain. We conclude that improved experimental and theoretical models of absorption of curcumin prodrugs, development of accurate analytical methods for simultaneous measurement of plasma levels of prodrug and released curcumin, and acquisition of more pharmacokinetic data in animal models for dose prediction in humans are required to facilitate movement of curcumin prodrugs into clinical trials.

  1. Dendrimer Prodrugs

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    Soraya da Silva Santos

    2016-05-01

    Full Text Available The main objective of this review is to describe the importance of dendrimer prodrugs in the design of new drugs, presenting numerous applications of these nanocomposites in the pharmaceutical field. Therefore, the use of dendrimer prodrugs as carrier for drug delivery, to improve pharmacokinetic properties of prototype, to promote drug sustained-release, to increase selectivity and, consequently, to decrease toxicity, are just some examples of topics that have been extensively reported in the literature, especially in the last decade. The examples discussed here give a panel of the growing interest dendrimer prodrugs have been evoking in the scientific community.

  2. Comparative pharmacokinetics of two prodrugs of zidovudine in rabbits: enhanced levels of zidovudine in brain tissue.

    Science.gov (United States)

    Lupia, R H; Ferencz, N; Lertora, J J; Aggarwal, S K; George, W J; Agrawal, K C

    1993-04-01

    The pharmacokinetics of two prodrugs of zidovudine (AZT), 1,4-dihydro-1-methyl-3-[(pyridylcarbonyl)oxy] ester and isoleucinyl ester (DPAZT and IAZT, respectively), were investigated in a rabbit model to determine their potential utility as drugs against human immunodeficiency virus. Drugs were administered by intravenous infusion over 5 min at doses equal to 10 mg of AZT per kg of body weight. The levels of the prodrugs and of released AZT in plasma, cerebrospinal fluid (CSF), and brain were determined by high-performance liquid chromatography analysis. DPAZT disappeared rapidly from plasma, whereas IAZT maintained a sustained level in plasma for up to 4 h. The levels in plasma of AZT released from DPAZT were consistently lower than the levels of AZT released from IAZT or AZT itself. At 75 min after infusion of AZT, DPAZT, and IAZT, the CSF plasma AZT ratios were 0.23, 0.30, and 0.25, while the brain/CSF AZT ratios were 0.32, 0.63, and 0.64, respectively. These results indicate that the administration of each of the prodrugs produced a higher concentration of AZT in the brain than did the direct administration of AZT. Both prodrugs therefore may be superior to AZT itself with respect to achieving anti-human immunodeficiency virus concentrations within the central nervous system.

  3. JS-K, a Nitric Oxide Prodrug, Has Enhanced Cytotoxicity in Colon Cancer Cells with Knockdown of Thioredoxin Reductase 1

    Science.gov (United States)

    Edes, Kornelia; Cassidy, Pamela; Shami, Paul J.; Moos, Philip J.

    2010-01-01

    Background The selenoenzyme thioredoxin reductase 1 has a complex role relating to cell growth. It is induced as a component of the cellular response to potentially mutagenic oxidants, but also appears to provide growth advantages to transformed cells by inhibiting apoptosis. In addition, selenocysteine-deficient or alkylated forms of thioredoxin reductase 1 have also demonstrated oxidative, pro-apoptotic activity. Therefore, a greater understanding of the role of thioredoxin reductase in redox initiated apoptotic processes is warranted. Methodology The role of thioredoxin reductase 1 in RKO cells was evaluated by attenuating endogenous thioredoxin reductase 1 expression with siRNA and then either inducing a selenium-deficient thioredoxin reductase or treatment with distinct redox challenges including, hydrogen peroxide, an oxidized lipid, 4-hydroxy-2-nonenol, and a nitric oxide donating prodrug. Thioredoxin redox status, cellular viability, and effector caspase activity were measured. Conclusions/Significance In cells with attenuated endogenous thioredoxin reductase 1, a stably integrated selenocysteine-deficient form of the enzyme was induced but did not alter either the thioredoxin redox status or the cellular growth kinetics. The oxidized lipid and the nitric oxide donor demonstrated enhanced cytotoxicity when thioredoxin reductase 1 was knocked-down; however, the effect was more pronounced with the nitric oxide prodrug. These results are consistent with the hypothesis that attenuation of the thioredoxin-system can promote apoptosis in a nitric oxide-dependent manner. PMID:20098717

  4. Enhancing the intestinal absorption of molecules containing the polar guanidino functionality: a double-targeted prodrug approach.

    Science.gov (United States)

    Sun, Jing; Dahan, Arik; Amidon, Gordon L

    2010-01-28

    A prodrug strategy was applied to guanidino-containing analogues to increase oral absorption via hPEPT1 and hVACVase. l-Valine, l-isoleucine, and l-phenylalanine esters of [3-(hydroxymethyl)phenyl]guanidine (3-HPG) were synthesized and evaluated for transport and activation. In HeLa/hPEPT1 cells, Val-3-HPG and Ile-3-HPG exhibited high affinity to hPEPT1 (IC(50): 0.65 and 0.63 mM, respectively), and all three l-amino acid esters showed higher uptake (2.6- to 9-fold) than the parent compound 3-HPG. Val-3-HPG and Ile-3-HPG demonstrated remarkable Caco-2 permeability enhancement, and Val-3-HPG exhibited comparable permeability to valacyclovir. In rat perfusion studies, Val-3-HPG and Ile-3-HPG permeabilities were significantly higher than 3-HPG and exceeded/matched the high-permeability standard metoprolol, respectively. All the l-amino acid 3-HPG esters were effectively activated in HeLa and Caco-2 cell homogenates and were found to be good substrates of hVACVase (k(cat)/K(m) in mM(-1) x s(-1): Val-3-HPG, 3370; Ile-3-HPG, 1580; Phe-3-HPG, 1660). In conclusion, a prodrug strategy is effective at increasing the intestinal permeability of polar guanidino analogues via targeting hPEPT1 for transport and hVACVase for activation.

  5. Biotin-Pt (IV)-indomethacin hybrid: A targeting anticancer prodrug providing enhanced cancer cellular uptake and reversing cisplatin resistance.

    Science.gov (United States)

    Hu, Weiwei; Fang, Lei; Hua, Wuyang; Gou, Shaohua

    2017-10-01

    A Pt(IV) prodrug (2) composed of cancer-targeting biotin and nonsteroidal anti-inflammatory drug indomethacin in the axial positions of the six-coordinated octahedral geometry derived from cisplatin was developed, which could be highly accumulated in cancer cells more than normal ones and activated by endogenous reducing molecules to release cisplatin and indomethacin moieties simultaneously to inhibit tumor progression synergistically. In vitro assays revealed that 2 exhibited significantly selective inhibition to the tested cancer cell lines and sensitivity to cisplatin resistant cancer cells. Moreover, 2 presented cyclooxygenases inhibition properties to reduce tumor-associated inflammation, reduced the invasiveness of the highly aggressive PC-3 cells, and disrupted capillary-like tube formation in EA.hy926 cells. In all, this study offers a new strategy to enhance sensitivity and reduce toxicity of cisplatin. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Antiparkinson Prodrugs

    Directory of Open Access Journals (Sweden)

    Laura Serafina Cerasa

    2008-01-01

    Full Text Available Parkinson`s disease (PD is a progressive, neurodegenerative disorder whichinvolves the loss of dopaminergic neurons of the substantia nigra pars compacta. Currenttherapy is essentially symptomatic, and L-Dopa (LD, the direct precursor of dopamine(DA, is the treatment of choice in more advanced stages of the disease. Substitutiontherapy with LD is, however, associated with a number of acute problems. The peripheralconversion of LD by amino acid decarboxylase (AADC to DA is responsible for thetypical gastrointestinal (nausea, emesis and cardiovascular (arrhythmia, hypotension sideeffects. To minimize the conversion to DA outside the central nervous system (CNS LD isusually given in combination with peripheral inhibitors of AADC (carbidopa andbenserazide. In spite of that, other central nervous side effects such as dyskinesia, on-offphenomenon and end-of-dose deterioration still remain. The main factors responsible forthe poor bioavailability and the wide range of inter- and intra-patient variations of plasmalevels are the drug’s physical-chemical properties: low water and lipid solubility, resultingin unfavourable partition, and the high susceptibility to chemical and enzymaticdegradation. In order to improve the bioavailability, the prodrug approach appeared to bethe most promising and some LD prodrugs have been prepared in an effort to solve theseproblems. We report here a review of progress in antiparkinson prodrugs, focusing onchemical structures mainly related to LD, DA and dopaminergic agonists.

  7. Drosophila deoxyribonucleoside kinase mutants with enhanced ability to phosphorylate purine analogs

    DEFF Research Database (Denmark)

    Knecht, Wolfgang; Rozpedowska, E.; Le Breton, C.

    2007-01-01

    Transduced deoxyribonucleoside kinases (dNK) can be used to kill recipient cells in combination with nucleoside prodrugs. The Drosophila melanogaster multisubstrate dNK (Dm-dNK) displays a superior turnover rate and has a great plasticity regarding its substrates. We used directed evolution...

  8. Tailoring acyclovir prodrugs with enhanced antiviral activity: rational design, synthesis, human plasma stability and in vitro evaluation.

    Science.gov (United States)

    Chayrov, Radoslav L; Stylos, Evgenios K; Chatziathanasiadou, Maria V; Chuchkov, Kiril N; Tencheva, Aleksandra I; Kostagianni, Androniki D; Milkova, Tsenka S; Angelova, Assia L; Galabov, Angel S; Shishkov, Stoyan A; Todorov, Daniel G; Tzakos, Andreas G; Stankova, Ivanka G

    2018-05-19

    Bile acid prodrugs have served as a viable strategy for refining the pharmaceutical profile of parent drugs through utilizing bile acid transporters. A series of three ester prodrugs of the antiherpetic drug acyclovir (ACV) with the bile acids cholic, chenodeoxycholic and deoxycholic were synthesized and evaluated along with valacyclovir for their in vitro antiviral activity against herpes simplex viruses type 1 and type 2 (HSV-1, HSV-2). The in vitro antiviral activity of the three bile acid prodrugs was also evaluated against Epstein-Barr virus (EBV). Plasma stability assays, utilizing ultra-high performance liquid chromatography coupled with tandem mass spectrometry, in vitro cytotoxicity and inhibitory experiments were conducted in order to establish the biological profile of ACV prodrugs. The antiviral assays demonstrated that ACV-cholate had slightly better antiviral activity than ACV against HSV-1, while it presented an eight-fold higher activity with respect to ACV against HSV-2. ACV-chenodeoxycholate presented a six-fold higher antiviral activity against HSV-2 with respect to ACV. Concerning EBV, the highest antiviral effect was demonstrated by ACV-chenodeoxycholate. Human plasma stability assays revealed that ACV-deoxycholate was more stable than the other two prodrugs. These results suggest that decorating the core structure of ACV with bile acids could deliver prodrugs with amplified antiviral activity.

  9. Catalase-loaded cisplatin-prodrug-constructed liposomes to overcome tumor hypoxia for enhanced chemo-radiotherapy of cancer.

    Science.gov (United States)

    Zhang, Rui; Song, Xuejiao; Liang, Chao; Yi, Xuan; Song, Guosheng; Chao, Yu; Yang, Yu; Yang, Kai; Feng, Liangzhu; Liu, Zhuang

    2017-09-01

    Aiming at improved therapeutic efficacies, the combination of chemotherapy and radiotherapy (chemo-radiotherapy) has been widely studied and applied in clinic. However, the hostile characteristics of tumor microenvironment such as hypoxia often limit the efficacies in both types of cancer therapies. Herein, catalase (CAT), an antioxidant enzyme, is encapsulated inside liposomes constituted by cisplatin (IV)-prodrug-conjugated phospholipid, forming CAT@Pt (IV)-liposome for enhanced chemo-radiotherapy of cancer. After being loaded inside liposomes, CAT within CAT@Pt (IV)-liposome shows retained and well-protected enzyme activity, and is able to trigger decomposition of H 2 O 2 produced by tumor cells, so as to produce additional oxygen for hypoxia relief. As the result, treatment of CAT@Pt (IV)-liposome induces the highest level of DNA damage in cancer cells after X-ray radiation compared to the control groups. In vivo tumor treatment further demonstrates a remarkably improved therapeutic outcome in chemo-radiotherapy with such CAT@Pt (IV)-liposome nanoparticles. Hence, an exquisite type of liposome-based nanoparticles is developed in this work by integrating cisplatin-based chemotherapy and catalase-induced tumor hypoxia relief together for combined chemo-radiotherapy with great synergistic efficacy, promising for clinical translation in cancer treatment. Copyright © 2017. Published by Elsevier Ltd.

  10. Enhanced Brain Delivery of 2-(Phosphonomethyl)pentanedioic Acid Following Intranasal Administration of Its gamma-Substituted Ester Prodrugs

    Czech Academy of Sciences Publication Activity Database

    Nedelcovych, M.; Dash, R. P.; Tenora, Lukáš; Zimmermann, S. C.; Gadiano, A. J.; Garrett, C.; Alt, J.; Hollinger, K. R.; Pommier, E.; Jančařík, Andrej; Rojas, C.; Thomas, A. G.; Wu, Y.; Wozniak, K.; Majer, Pavel; Slusher, B. S.; Rais, R.

    2017-01-01

    Roč. 14, č. 10 (2017), s. 3248-3257 ISSN 1543-8384 Institutional support: RVO:61388963 Keywords : 2-PMPA * glutamate carboxypeptidase II * neurological disease * intranasal * pharmacokinetics * prodrugs Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 4.440, year: 2016

  11. Modern Prodrug Design for Targeted Oral Drug Delivery

    Directory of Open Access Journals (Sweden)

    Arik Dahan

    2014-10-01

    Full Text Available The molecular information that became available over the past two decades significantly influenced the field of drug design and delivery at large, and the prodrug approach in particular. While the traditional prodrug approach was aimed at altering various physiochemical parameters, e.g., lipophilicity and charge state, the modern approach to prodrug design considers molecular/cellular factors, e.g., membrane influx/efflux transporters and cellular protein expression and distribution. This novel targeted-prodrug approach is aimed to exploit carrier-mediated transport for enhanced intestinal permeability, as well as specific enzymes to promote activation of the prodrug and liberation of the free parent drug. The purpose of this article is to provide a concise overview of this modern prodrug approach, with useful successful examples for its utilization. In the past the prodrug approach used to be viewed as a last option strategy, after all other possible solutions were exhausted; nowadays this is no longer the case, and in fact, the prodrug approach should be considered already in the very earliest development stages. Indeed, the prodrug approach becomes more and more popular and successful. A mechanistic prodrug design that aims to allow intestinal permeability by specific transporters, as well as activation by specific enzymes, may greatly improve the prodrug efficiency, and allow for novel oral treatment options.

  12. Enhanced casein kinase II activity in human tumour cell cultures

    DEFF Research Database (Denmark)

    Prowald, K; Fischer, H; Issinger, O G

    1984-01-01

    Casein kinase II (CKII) activity is enhanced as much as 2-3 fold in established and 4-5-fold in transformed human cell lines when compared to that of fibroblasts and primary human tumour cell cultures where CKII activity never exceeded a basic level. The high activity of CKII in transformed cells...

  13. Targeted enzyme prodrug therapies.

    Science.gov (United States)

    Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

    2010-09-01

    The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

  14. Potential Development of Tumor-Targeted Oral Anti-Cancer Prodrugs: Amino Acid and Dipeptide Monoester Prodrugs of Gemcitabine.

    Science.gov (United States)

    Tsume, Yasuhiro; Drelich, Adam J; Smith, David E; Amidon, Gordon L

    2017-08-10

    One of the main obstacles for cancer therapies is to deliver medicines effectively to target sites. Since stroma cells are developed around tumors, chemotherapeutic agents have to go through stroma cells in order to reach tumors. As a method to improve drug delivery to the tumor site, a prodrug approach for gemcitabine was adopted. Amino acid and dipeptide monoester prodrugs of gemcitabine were synthesized and their chemical stability in buffers, resistance to thymidine phosphorylase and cytidine deaminase, antiproliferative activity, and uptake/permeability in HFF cells as a surrogate to stroma cells were determined and compared to their parent drug, gemcitabine. The activation of all gemcitabine prodrugs was faster in pancreatic cell homogenates than their hydrolysis in buffer, suggesting enzymatic action. All prodrugs exhibited great stability in HFF cell homogenate, enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase, and deamination by cytidine deaminase compared to their parent drug. All gemcitabine prodrugs exhibited higher uptake in HFF cells and better permeability across HFF monolayers than gemcitabine, suggesting a better delivery to tumor sites. Cell antiproliferative assays in Panc-1 and Capan-2 pancreatic ductal cell lines indicated that the gemcitabine prodrugs were more potent than their parent drug gemcitabine. The transport and enzymatic profiles of gemcitabine prodrugs suggest their potential for delayed enzymatic bioconversion and enhanced resistance to metabolic enzymes, as well as for enhanced drug delivery to tumor sites, and cytotoxic activity in cancer cells. These attributes would facilitate the prolonged systemic circulation and improved therapeutic efficacy of gemcitabine prodrugs.

  15. Prodrugs of Pyrazolo[3,4-d]pyrimidines: From Library Synthesis to Evaluation as Potential Anticancer Agents in an Orthotopic Glioblastoma Model.

    Science.gov (United States)

    Vignaroli, Giulia; Iovenitti, Giulia; Zamperini, Claudio; Coniglio, Federica; Calandro, Pierpaolo; Molinari, Alessio; Fallacara, Anna Lucia; Sartucci, Andrea; Calgani, Alessia; Colecchia, David; Mancini, Andrea; Festuccia, Claudio; Dreassi, Elena; Valoti, Massimo; Musumeci, Francesca; Chiariello, Mario; Angelucci, Adriano; Botta, Maurizio; Schenone, Silvia

    2017-07-27

    Pyrazolo[3,4-d]pyrimidines are potent protein kinase inhibitors with promising antitumor activity but suboptimal aqueous solubility, consequently worth being further optimized. Herein, we present the one-pot two-step procedure for the synthesis of a set of pyrazolo[3,4-d]pyrimidine prodrugs (1a-8a and 9a-e) with higher aqueous solubility and enhanced pharmacokinetic and therapeutic properties. ADME studies demonstrated for the most promising prodrugs a better aqueous solubility, a favorable hydrolysis in human and murine serum, and an increased ability to cross cell membranes with respect to the parental drugs, explaining their better 24 h in vitro cytotoxicity against human glioblastoma U87 cell line. Finally, the 4-4a couple of drug/prodrug was also evaluated in vivo, revealing a profitable pharmacokinetic profile of the prodrug associated with a good efficacy. The application of the prodrug approach demonstrated to be a successful strategy for improving aqueous solubility of the parental drugs, determining a positive impact also in their biological efficacy.

  16. Gene Directed Enzyme Prodrug Therapy Using Rabbit Cytochrome P450 4B1 in Murine Colon Adenocarcinoma

    International Nuclear Information System (INIS)

    Kim, Sung Joo; Kang, Joo Hyun; Lee, Tae Sup; Kim, Kyeong Min; Woo, Kwang Sun; Chung, Wee Sup; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo

    2007-01-01

    The conventional cancer therapy is chemotherapy, surgical resection and/or radiotherapy. Chemotherapy using cytotoxic drug has some problems with lack of tumor selectivity resulting in toxicity to normal tissues. To enhance the tumor selectivity of cytotoxic drug, the application of suicidal gene therapy technology was designed. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a non-toxic prodrug into a cytotoxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1- tk) and cytosine deaminase (cd). Recently, a new prodrug-converting enzyme based on rabbit cytochrome P450 4B1 gene (cyp4B1) has been reported for therapy of experimental brain tumor. This enzyme activates the prodrugs such as 4-ipomeanol (4-IM) and 2- aminoanthracene (2-AA) to highly reactive furane epoxide and unsaturated dialdehyde intermediate, respectively. DNA alkylation seems to be the main mechanism of cytotoxicity of these activated drugs. In this study, we isolated cyp4B1 cDNA from rabbit lung, transduced cyp4B1 expression vector into murine colon cancer cell, and then analyzed the cytotoxic properties of cyp4b1-activated 2-AA in cyp4B1 transduced cells to verify the cyp4B1 enzyme system for gene directed enzyme prodrug therapy

  17. Gene Directed Enzyme Prodrug Therapy Using Rabbit Cytochrome P450 4B1 in Murine Colon Adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Joo; Kang, Joo Hyun; Lee, Tae Sup; Kim, Kyeong Min; Woo, Kwang Sun; Chung, Wee Sup; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2007-07-01

    The conventional cancer therapy is chemotherapy, surgical resection and/or radiotherapy. Chemotherapy using cytotoxic drug has some problems with lack of tumor selectivity resulting in toxicity to normal tissues. To enhance the tumor selectivity of cytotoxic drug, the application of suicidal gene therapy technology was designed. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a non-toxic prodrug into a cytotoxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1- tk) and cytosine deaminase (cd). Recently, a new prodrug-converting enzyme based on rabbit cytochrome P450 4B1 gene (cyp4B1) has been reported for therapy of experimental brain tumor. This enzyme activates the prodrugs such as 4-ipomeanol (4-IM) and 2- aminoanthracene (2-AA) to highly reactive furane epoxide and unsaturated dialdehyde intermediate, respectively. DNA alkylation seems to be the main mechanism of cytotoxicity of these activated drugs. In this study, we isolated cyp4B1 cDNA from rabbit lung, transduced cyp4B1 expression vector into murine colon cancer cell, and then analyzed the cytotoxic properties of cyp4b1-activated 2-AA in cyp4B1 transduced cells to verify the cyp4B1 enzyme system for gene directed enzyme prodrug therapy.

  18. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Directory of Open Access Journals (Sweden)

    Yoichi Takakusagi

    Full Text Available BACKGROUND: TH-302 is a hypoxia-activated prodrug (HAP of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. METHODOLOGY/RESULTS: The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2, with minimal effect under aerobic conditions (21% O2. Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3. Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3, significantly delayed tumor growth. CONCLUSIONS/SIGNIFICANCE: Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the

  19. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Takakusagi, Yoichi; Matsumoto, Shingo; Saito, Keita; Matsuo, Masayuki; Kishimoto, Shun; Wojtkowiak, Jonathan W; DeGraff, William; Kesarwala, Aparna H; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Munasinghe, Jeeva P; Gillies, Robert J; Mitchell, James B; Hart, Charles P; Krishna, Murali C

    2014-01-01

    TH-302 is a hypoxia-activated prodrug (HAP) of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR) oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2), with minimal effect under aerobic conditions (21% O2). Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3). Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3)), significantly delayed tumor growth. Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the appropriate tumor size and oxygen concentration.

  20. JS-K, a GST-activated nitric oxide donor prodrug, enhances chemo-sensitivity in renal carcinoma cells and prevents cardiac myocytes toxicity induced by Doxorubicin.

    Science.gov (United States)

    Qiu, Mingning; Ke, Longzhi; Zhang, Sai; Zeng, Xin; Fang, Zesong; Liu, Jianjun

    2017-08-01

    Doxorubicin, a highly effective and widely used anthracycline antibiotic in multiple chemotherapy regimens, has been limited by its cardiotoxicity. The aim of this study is to investigate the effect of nitric oxide donor prodrug JS-K on proliferation and apoptosis in renal carcinoma cells and cardiac myocytes toxicity induced by Doxorubicin and to explore possible p53-related mechanism in renal carcinoma cells. The effect of JS-K on anti-cancer activity of Doxorubicin was investigated in renal carcinoma cells via detecting cell proliferation, cytotoxicity, cell death and apoptosis and expressions of apoptotic-related proteins. Effect of p53 on the combination of JS-K and Doxorubicin was determined using p53 inhibitor Pifithrin-α and p53 activator III. Furthermore, the effect of JS-K on cardiac myocytes toxicity of Doxorubicin was investigated in H9c2 (2-1) cardiac myocytes via measuring cell growth, cell death and apoptosis, expressions of proteins involved in apoptosis and intracellular reactive oxygen species. We demonstrated that JS-K could increase Doxorubicin-induced renal carcinoma cell growth suppression and apoptosis and could increase expressions of proteins that are involved in apoptosis. Additionally, Pifithrin-α reversed the promoting effect of JS-K on Doxorubicin-induced renal carcinoma cell apoptosis; conversely, the p53 activator III exacerbated the promoting effect of JS-K on Doxorubicin-induced renal carcinoma cell apoptosis. Furthermore, JS-K protected H9c2 (2-1) cardiac myocytes against Doxorubicin-induced toxicity and decreased Doxorubicin-induced reactive oxygen species production. JS-K enhances the anti-cancer activity of Doxorubicin in renal carcinoma cells by upregulating p53 expression and prevents cardiac myocytes toxicity of Doxorubicin by decreasing oxidative stress.

  1. Adenoviral delivery of pan-caspase inhibitor p35 enhances bystander killing by P450 gene-directed enzyme prodrug therapy using cyclophosphamide+

    International Nuclear Information System (INIS)

    Doloff, Joshua C; Su, Ting; Waxman, David J

    2010-01-01

    Cytochrome P450-based suicide gene therapy for cancer using prodrugs such as cyclophosphamide (CPA) increases anti-tumor activity, both directly and via a bystander killing mechanism. Bystander cell killing is essential for the clinical success of this treatment strategy, given the difficulty of achieving 100% efficient gene delivery in vivo using current technologies. Previous studies have shown that the pan-caspase inhibitor p35 significantly increases CPA-induced bystander killing by tumor cells that stably express P450 enzyme CYP2B6 (Schwartz et al, (2002) Cancer Res. 62: 6928-37). To further develop this approach, we constructed and characterized a replication-defective adenovirus, Adeno-2B6/p35, which expresses p35 in combination with CYP2B6 and its electron transfer partner, P450 reductase. The expression of p35 in Adeno-2B6/p35-infected tumor cells inhibited caspase activation, delaying the death of the CYP2B6 'factory' cells that produce active CPA metabolites, and increased bystander tumor cell killing compared to that achieved in the absence of p35. Tumor cells infected with Adeno-2B6/p35 were readily killed by cisplatin and doxorubicin, indicating that p35 expression is not associated with acquisition of general drug resistance. Finally, p35 did not inhibit viral release when the replication-competent adenovirus ONYX-017 was used as a helper virus to facilitate co-replication and spread of Adeno-2B6/p35 and further increase CPA-induced bystander cell killing. The introduction of p35 into gene therapeutic regimens constitutes an effective approach to increase bystander killing by cytochrome P450 gene therapy. This strategy may also be used to enhance other bystander cytotoxic therapies, including those involving the production of tumor cell toxic protein products

  2. Activity of the hypoxia-activated pro-drug TH-302 in hypoxic and perivascular regions of solid tumors and its potential to enhance therapeutic effects of chemotherapy.

    Science.gov (United States)

    Saggar, Jasdeep K; Tannock, Ian F

    2014-06-01

    Many chemotherapy drugs have poor therapeutic activity in regions distant from tumor blood vessels because of poor tissue penetration and low cytotoxic activity against slowly-proliferating cells. The hypoxia-activated pro-drug TH-302 may have selective toxicity for hypoxic and neighboring cells in tumors. Here we characterize the spatial distribution and ability of TH-302 to selectively target hypoxic regions and complement the effect of doxorubicin and docetaxel by modifying biomarker distribution. Athymic nude mice bearing human breast MCF-7 or prostate PC-3 tumors were treated with doxorubicin or docetaxel respectively and TH-302 alone or in combination. Biomarkers of drug effect including γH2aX (a marker of DNA damage), cleaved caspase-3 or -6 (markers of apoptosis) and reduction in Ki-67 (a marker of cell proliferation) were quantified in tumor sections in relation to functional blood vessels (recognized by DiOC7) and hypoxia (recognized by EF5) using immunohistochemistry. γH2aX expression at 10 min and cleaved caspase-3 or -6 at 24 hr after doxorubicin or docetaxel decreased with increasing distance from tumor blood vessels, with minimal expression in hypoxic regions; maximum reduction in Ki67 levels was observed in regions closest to vasculature at 24 hr. TH-302 induced maximal cell damage in hypoxic and neighboring regions, but was also active in tumor regions closer to blood vessels. TH-302 given 4 hr before doxorubicin or docetaxel increased DNA damage and apoptosis throughout the tumor compared to chemotherapy alone. When given with doxorubicin or docetaxel, TH-302 complements and enhances anticancer effects in both perivascular and hypoxic regions but also increases toxicity. © 2013 UICC.

  3. Enhanced expression of a calcium-dependent protein kinase

    Indian Academy of Sciences (India)

    Among the downstream targets of calcium in plants, calcium-dependent protein kinases (CDPKs) form an interesting class of kinases which are activated by calcium binding. They have been implicated in a diverse array of responses to hormonal and environmental stimuli. In order to dissect the role of CDPKs in the moss ...

  4. Bystander or No Bystander for Gene Directed Enzyme Prodrug Therapy

    Directory of Open Access Journals (Sweden)

    Adam V. Patterson

    2009-11-01

    Full Text Available Gene directed enzyme prodrug therapy (GDEPT of cancer aims to improve the selectivity of chemotherapy by gene transfer, thus enabling target cells to convert nontoxic prodrugs to cytotoxic drugs. A zone of cell kill around gene-modified cells due to transfer of toxic metabolites, known as the bystander effect, leads to tumour regression. Here we discuss the implications of either striving for a strong bystander effect to overcome poor gene transfer, or avoiding the bystander effect to reduce potential systemic effects, with the aid of three successful GDEPT systems. This review concentrates on bystander effects and drug development with regard to these enzyme prodrug combinations, namely herpes simplex virus thymidine kinase (HSV-TK with ganciclovir (GCV, cytosine deaminase (CD from bacteria or yeast with 5-fluorocytodine (5-FC, and bacterial nitroreductase (NfsB with 5-(azaridin-1-yl-2,4-dinitrobenzamide (CB1954, and their respective derivatives.

  5. The Effect of 5-Aminolevulinic Acid on Cytochrome P450-Mediated Prodrug Activation.

    Directory of Open Access Journals (Sweden)

    Mai Miura

    Full Text Available Of late, numerous prodrugs are widely used for therapy. The hemeprotein cytochrome P450 (CYP catalyzes the activation of prodrugs to form active metabolites. Therefore, the activation of CYP function might allow the use of lower doses of prodrugs and decrease toxicity. We hypothesized that the addition of 5-aminolevulinic acid (ALA, a precursor in the porphyrin biosynthetic pathway, enhances the synthesis of heme, leading to the up-regulation of CYP activity. To test this hypothesis, we treated a human gastric cancer cell line with ALA and determined the effect on CYP-dependent prodrug activation. For this purpose, we focused on the anticancer prodrug tegafur, which is converted to its active metabolite 5-fluorouracil (5-FU mainly by CYP2A6. We show here that ALA increased CYP2A6-dependent tegafur activation, suggesting that ALA elevated CYP activity and potentiated the activation of the prodrug.

  6. Allergic sensitization enhances the contribution of Rho-kinase to airway smooth muscle contraction

    NARCIS (Netherlands)

    Schaafsma, D.; Gosens, Reinout; Bos, I.S.T.; Meurs, Herman; Zaagsma, Hans; Nelemans, Herman

    2004-01-01

    1 Repeated allergen challenge has been shown to increase the role of Rho-kinase in airway smooth muscle (ASM) contraction. We considered the possibility that active allergic sensitization by itself, that is, without subsequent allergen exposure, could be sufficient to enhance Rho-kinase-mediated ASM

  7. Synthesis, characterization and pharmacological evaluation of amide prodrugs of Flurbiprofen

    International Nuclear Information System (INIS)

    Mishra, Ashutosh; Veerasamy, Ravichandran; Jain, Prateek Kumar; Dixit, Vinod Kumar; Agrawal, Ram Kishor

    2008-01-01

    Flurbiprofen (FB) suffers from the general side effects of NSAIDs, owing to presence of free carboxylic acid group. The study was aimed to retard the adverse effects of gastrointestinal origin. Ten prodrugs of FB were synthesized by amidation with ethyl esters of amino acids, namely, glycine, L-phenylalanine, L-tryptophan, L-valine, L-isoleucine, L-alanine, L-leucine, L-glutamic acid, L-aspartic acid and β alanine. Purified synthesized prodrugs were characterized by m.p., TLC, solubility, partition coefficients, elemental analyses, UV, FTIR, NMR and MS. Synthesized prodrugs were subjected for bioavailability studies, analgesic, anti-inflammatory activities and ulcerogenic index. Marked reduction of ulcerogenic index and comparable analgesic, antiinflammatory activities were obtained in all cases as compared to FB. Among synthesized prodrugs AR-9, AR-10 and AR-2 showing excellent pharmacological response and encouraging hydrolysis rate both in (Simulated Intestinal Fluid) SIF and in 80% human plasma. Prodrugs with increased aliphatic side chain length or introduction of aromatic substituent resulted in enhanced partition coefficient but diminished dissolution and hydrolysis rate. Such prodrugs can be considered for sustained release purpose. (author)

  8. Synthesis, characterization and pharmacological evaluation of amide prodrugs of Flurbiprofen

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Ashutosh; Veerasamy, Ravichandran; Jain, Prateek Kumar; Dixit, Vinod Kumar; Agrawal, Ram Kishor [Dr. H. S. Gour Vishwavidyalaya, Sagar (India). Dept. of Pharmaceutical Sciences. Pharmaceutical Chemistry Research Lab.]. E-mail: dragrawal2001@yahoo.co.in

    2008-07-01

    Flurbiprofen (FB) suffers from the general side effects of NSAIDs, owing to presence of free carboxylic acid group. The study was aimed to retard the adverse effects of gastrointestinal origin. Ten prodrugs of FB were synthesized by amidation with ethyl esters of amino acids, namely, glycine, L-phenylalanine, L-tryptophan, L-valine, L-isoleucine, L-alanine, L-leucine, L-glutamic acid, L-aspartic acid and {beta} alanine. Purified synthesized prodrugs were characterized by m.p., TLC, solubility, partition coefficients, elemental analyses, UV, FTIR, NMR and MS. Synthesized prodrugs were subjected for bioavailability studies, analgesic, anti-inflammatory activities and ulcerogenic index. Marked reduction of ulcerogenic index and comparable analgesic, antiinflammatory activities were obtained in all cases as compared to FB. Among synthesized prodrugs AR-9, AR-10 and AR-2 showing excellent pharmacological response and encouraging hydrolysis rate both in (Simulated Intestinal Fluid) SIF and in 80% human plasma. Prodrugs with increased aliphatic side chain length or introduction of aromatic substituent resulted in enhanced partition coefficient but diminished dissolution and hydrolysis rate. Such prodrugs can be considered for sustained release purpose. (author)

  9. Dual-therapeutic reporter genes fusion for enhanced cancer gene therapy and imaging.

    Science.gov (United States)

    Sekar, T V; Foygel, K; Willmann, J K; Paulmurugan, R

    2013-05-01

    Two of the successful gene-directed enzyme prodrug therapies include herpes simplex virus-thymidine kinase (HSV1-TK) enzyme-ganciclovir prodrug and the Escherichia coli nitroreductase (NTR) enzyme-CB1954 prodrug strategies; these enzyme-prodrug combinations produce activated cytotoxic metabolites of the prodrugs capable of tumor cell death by inhibiting DNA synthesis and killing quiescent cells, respectively. Both these strategies also affect significant bystander cell killing of neighboring tumor cells that do not express these enzymes. We have developed a dual-combination gene strategy, where we identified HSV1-TK and NTR fused in a particular orientation can effectively kill tumor cells when the tumor cells are treated with a fusion HSV1-TK-NTR gene- along with a prodrug combination of GCV and CB1954. In order to determine whether the dual-system demonstrate superior therapeutic efficacy than either HSV1-TK or NTR systems alone, we conducted both in vitro and in vivo tumor xenograft studies using triple negative SUM159 breast cancer cells, by evaluating the efficacy of cell death by apoptosis and necrosis upon treatment with the dual HSV1-TK genes-GCV-CB1954 prodrugs system, and compared the efficiency to HSV1-TK-GCV and NTR-CB1954. Our cell-based studies, tumor regression studies in xenograft mice, histological analyses of treated tumors and bystander studies indicate that the dual HSV1-TK-NTR-prodrug system is two times more efficient even with half the doses of both prodrugs than the respective single gene-prodrug system, as evidenced by enhanced apoptosis and necrosis of tumor cells in vitro in culture and xenograft of tumor tissues in animals.

  10. Prodrug Strategies for Paclitaxel

    Directory of Open Access Journals (Sweden)

    Ziyuan Meng

    2016-05-01

    Full Text Available Paclitaxel is an anti-tumor agent with remarkable anti-tumor activity and wide clinical uses. However, it is also faced with various challenges especially for its poor water solubility and low selectivity for the target. To overcome these disadvantages of paclitaxel, approaches using small molecule modifications and macromolecule modifications have been developed by many research groups from all over the world. In this review, we discuss the different strategies especially prodrug strategies that are currently used to make paclitaxel more effective.

  11. Amino Acid Prodrugs: An Approach to Improve the Absorption of HIV-1 Protease Inhibitor, Lopinavir

    Directory of Open Access Journals (Sweden)

    Mitesh Patel

    2014-04-01

    Full Text Available Poor systemic concentrations of lopinavir (LPV following oral administration occur due to high cellular efflux by P-glycoprotein (P-gp and multidrug resistance-associated proteins (MRPs and extensive metabolism by CYP3A4 enzymes. In this study, amino acid prodrugs of LPV were designed and investigated for their potential to circumvent efflux processes and first pass effects. Three amino acid prodrugs were synthesized by conjugating isoleucine, tryptophan and methionine to LPV. Prodrug formation was confirmed by the LCMS/MS and NMR technique. Interaction of LPV prodrugs with efflux proteins were carried out in P-gp (MDCK-MDR1 and MRP2 (MDCK-MRP2 transfected cells. Aqueous solubility studies demonstrated that prodrugs generate higher solubility relative to LPV. Prodrugs displayed higher stability under acidic conditions and degraded significantly with rise in pH. Uptake and transport data suggested that prodrugs carry significantly lower affinity towards P-gp and MRP2 relative to LPV. Moreover, prodrugs exhibited higher liver microsomal stability relative to LPV. Hence, amino acid prodrug modification might be a viable approach for enhancing LPV absorption across intestinal epithelial and brain endothelial cells which expresses high levels of P-gp and MRP2.

  12. Cytomegalovirus protease targeted prodrug development.

    Science.gov (United States)

    Sabit, Hairat; Dahan, Arik; Sun, Jing; Provoda, Chester J; Lee, Kyung-Dall; Hilfinger, John H; Amidon, Gordon L

    2013-04-01

    Human cytomegalovirus (HCMV) is a prevalent virus that infects up to 90% of the population. The goal of this research is to determine if small molecular prodrug substrates can be developed for a specific HCMV encoded protease and thus achieve site-specific activation. HCMV encodes a 256 amino acid serine protease that is responsible for capsid assembly, an essential process for herpes virus production. The esterase activity of the more stable HCMV A143T/A144T protease mutant was evaluated with model p-nitrophenol (ONp) esters, Boc-Xaa-ONp (Ala, Leu, Ile, Val, Gln, Phe at the Xaa position). We demonstrate that the A143T/A144T mutant has esterase activity toward specific small ester compounds, e.g., Boc-L-Ala-ONp. Mono amino acid and dipeptide prodrugs of ganciclovir (GCV) were also synthesized and evaluated for hydrolysis by the A143T/A144T protease mutant in solution. Hydrolysis of these prodrugs was also evaluated in Caco-2 cell homogenates, human liver microsomes (HLMs), and rat and human plasma. For the selectivity potential of the prodrugs, the hydrolysis ratio was evaluated as a percentage of prodrug hydrolyzed by the HCMV protease over the percentages of prodrug hydrolyses by Caco-2 cell homogenates, HLMs, and human/rat plasma. A dipeptide prodrug of ganciclovir, Ac-l-Gln-l-Ala-GCV, emerged as a potential selective prodrug candidate. The results of this research demonstrate that targeting prodrugs for activation by a specific protease encoded by the infectious HCMV pathogen may be achievable.

  13. Ketobemidone prodrugs for buccal delivery

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    1992-01-01

    As part of studies aiming at developing a ketobemidone prodrug suitable for buccal or sublingual administration, the potential impact of saliva enzyme-catalyzed hydrolysis of various ester prodrugs was assessed. The hydrolysis of three ketobemidone esters in human whole saliva, obtained under con...... in the mouth and their rate of disintegration were shown to have some influence on the rate of saliva secretion and hence on saliva esterase activity but not to an extent compromising the efficient buccal or sublingual delivery of the ketobemidone prodrugs....

  14. Potential of amino acid/dipeptide monoester prodrugs of floxuridine in facilitating enhanced delivery of active drug to interior sites of tumors: a two-tier monolayer in vitro study.

    Science.gov (United States)

    Tsume, Yasuhiro; Hilfinger, John M; Amidon, Gordon L

    2011-10-01

    To evaluate the advantages of amino acid/dipeptide monoester prodrugs for cancer treatments by assessing the uptake and cytotoxic effects of floxuridine prodrugs in a secondary cancer cell monolayer following permeation across a primary cancer cell monolayer. The first Capan-2 monolayer was grown on membrane transwell inserts; the second monolayer was grown at the bottom of a plate. The permeation of floxuridine and its prodrugs across the first monolayer and the uptake and cell proliferation assay on secondary layer were sequentially determined. All floxuridine prodrugs exhibited greater permeation across the first Capan-2 monolayer than the parent drug. The correlation between uptake and growth inhibition in the second monolayer with intact prodrug permeating the first monolayer suggests that permeability and enzymatic stability are essential for sustained action of prodrugs in deeper layers of tumors. The correlation of uptake and growth inhibition were vastly superior for dipeptide prodrugs to those obtained with mono amino acid prodrugs. Although a tentative general overall correlation between intact prodrug and uptake or cytotoxic action was obtained, it appears that a mixture of floxuridine prodrugs with varying beneficial characteristics may be more effective in treating tumors.

  15. Stimuli-responsive PEGylated prodrugs for targeted doxorubicin delivery

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Minghui; Qian, Junmin, E-mail: jmqian@mail.xjtu.edu.cn; Liu, Xuefeng; Liu, Ting; Wang, Hongjie

    2015-05-01

    In recent years, stimuli-sensitive prodrugs have been extensively studied for the rapid “burst” release of antitumor drugs to enhance chemotherapeutic efficiency. In this study, a novel stimuli-sensitive prodrug containing galactosamine as a targeting moiety, poly(ethylene glycol)–doxorubicin (PEG–DOX) conjugate, was developed for targeting HepG2 human liver cancer cells. To obtain the PEG–DOX conjugate, both galactosamine-decorated poly(ethylene glycol) aldehyde (Gal-PEG-CHO) and methoxy poly(ethylene glycol) aldehyde (mPEG-CHO) were firstly synthesized and functionalized with dithiodipropionate dihydrazide (TPH) through direct reductive amination via Schiff's base formation, and then DOX molecules were chemically conjugated to the hydrazide end groups of TPH-functionalized Gal-/m-PEG chains via pH-sensitive hydrazone linkages. The chemical structures of TPH-functionalized PEG and PEG–DOX prodrug were confirmed by {sup 1}H NMR analysis. The PEG–DOX conjugate could self-assemble into spherical nanomicelles with a mean diameter of 140 nm, as indicated by transmission electron microscopy and dynamic light scattering. The drug loading content and loading efficiency in the prodrug nanomicelles were as high as 20 wt.% and 75 wt.%, respectively. In vitro drug release studies showed that DOX was released rapidly from the prodrug nanomicelles at the intracellular levels of pH and reducing agent. Cellular uptake and MTT experiments demonstrated that the galactosamine-decorated prodrug nanomicelles were more efficiently internalized into HepG2 cells via a receptor-mediated endocytosis process and exhibited a higher toxicity, compared with pristine prodrug nanomicelles. These results suggest that the novel Gal-PEG–DOX prodrug nanomicelles have tremendous potential for targeted liver cancer therapy. - Highlights: • A novel stimuli-responsive PEGylated prodrugs is synthesized. • PEGylated prodrugs can self-assemble into spherical nanoparticles (140 nm

  16. Leveraging Hypoxia-Activated Prodrugs to Prevent Drug Resistance in Solid Tumors.

    Directory of Open Access Journals (Sweden)

    Danika Lindsay

    2016-08-01

    Full Text Available Experimental studies have shown that one key factor in driving the emergence of drug resistance in solid tumors is tumor hypoxia, which leads to the formation of localized environmental niches where drug-resistant cell populations can evolve and survive. Hypoxia-activated prodrugs (HAPs are compounds designed to penetrate to hypoxic regions of a tumor and release cytotoxic or cytostatic agents; several of these HAPs are currently in clinical trial. However, preliminary results have not shown a survival benefit in several of these trials. We hypothesize that the efficacy of treatments involving these prodrugs depends heavily on identifying the correct treatment schedule, and that mathematical modeling can be used to help design potential therapeutic strategies combining HAPs with standard therapies to achieve long-term tumor control or eradication. We develop this framework in the specific context of EGFR-driven non-small cell lung cancer, which is commonly treated with the tyrosine kinase inhibitor erlotinib. We develop a stochastic mathematical model, parametrized using clinical and experimental data, to explore a spectrum of treatment regimens combining a HAP, evofosfamide, with erlotinib. We design combination toxicity constraint models and optimize treatment strategies over the space of tolerated schedules to identify specific combination schedules that lead to optimal tumor control. We find that (i combining these therapies delays resistance longer than any monotherapy schedule with either evofosfamide or erlotinib alone, (ii sequentially alternating single doses of each drug leads to minimal tumor burden and maximal reduction in probability of developing resistance, and (iii strategies minimizing the length of time after an evofosfamide dose and before erlotinib confer further benefits in reduction of tumor burden. These results provide insights into how hypoxia-activated prodrugs may be used to enhance therapeutic effectiveness in the

  17. Prodrug Strategy in Drug Development

    Directory of Open Access Journals (Sweden)

    Hajnal Kelemen

    2016-09-01

    Full Text Available Prodrugs are chemically modified derivatives introduced in therapy due to their advantageous physico-chemical properties (greater stability, improved solubility, increased permeability, used in inactive form. Biological effect is exerted by the active derivatives formed in organism through chemical transformation (biotransformation. Currently, 10% of pharmaceutical products are used as prodrugs, nearly half of them being converted to active form by hydrolysis, mainly by ester hydrolysis. The use of prodrugs aims to improve the bioavailability of compounds in order to resolve some unfavorable characteristics and to reduce first-pass metabolism. Other objectives are to increase drug absorption, to extend duration of action or to achieve a better tissue/organ selective transport in case of non-oral drug delivery forms. Prodrugs can be characterized by chemical structure, activation mechanism or through the presence of certain functional groups suitable for their preparation. Currently we distinguish in therapy traditional prodrugs prepared by chemical derivatisation, bioprecursors and targeted delivery systems. The present article is a review regarding the introduction and applications of prodrug design in various areas of drug development.

  18. Prodrugs as self-assembled hydrogels: a new paradigm for biomaterials.

    Science.gov (United States)

    Vemula, Praveen Kumar; Wiradharma, Nikken; Ankrum, James A; Miranda, Oscar R; John, George; Karp, Jeffrey M

    2013-12-01

    Prodrug-based self-assembled hydrogels represent a new class of active biomaterials that can be harnessed for medical applications, in particular the design of stimuli responsive drug delivery devices. In this approach, a promoiety is chemically conjugated to a known-drug to generate an amphiphilic prodrug that is capable of forming self-assembled hydrogels. Prodrug-based self-assembled hydrogels are advantageous as they alter the solubility of the drug, enhance drug loading, and eliminate the use of harmful excipients. In addition, self-assembled prodrug hydrogels can be designed to undergo controlled drug release or tailored degradation in response to biological cues. Herein we review the development of prodrug-based self-assembled hydrogels as an emerging class of biomaterials that overcome several common limitations encountered in conventional drug delivery. Published by Elsevier Ltd.

  19. The Dipeptide Monoester Prodrugs of Floxuridine and Gemcitabine—Feasibility of Orally Administrable Nucleoside Analogs

    Directory of Open Access Journals (Sweden)

    Yasuhiro Tsume

    2014-01-01

    Full Text Available Dipeptide monoester prodrugs of floxuridine and gemcitabine were synthesized. Their chemical stability in buffers, enzymatic stability in cell homogenates, permeability in mouse intestinal membrane along with drug concentration in mouse plasma, and anti-proliferative activity in cancer cells were determined and compared to their parent drugs. Floxuridine prodrug was more enzymatically stable than floxuridine and the degradation from prodrug to parent drug works as the rate-limiting step. On the other hand, gemcitabine prodrug was less enzymatically stable than gemcitabine. Those dipeptide monoester prodrugs exhibited 2.4- to 48.7-fold higher uptake than their parent drugs in Caco-2, Panc-1, and AsPC-1 cells. Floxuridine and gemcitabine prodrugs showed superior permeability in mouse jejunum to their parent drugs and exhibited the higher drug concentration in plasma after in situ mouse perfusion. Cell proliferation assays in ductal pancreatic cancer cells, AsPC-1 and Panc-1, indicated that dipeptide prodrugs of floxuridine and gemcitabine were more potent than their parent drugs. The enhanced potency of nucleoside analogs was attributed to their improved membrane permeability. The prodrug forms of 5¢-L-phenylalanyl-l-tyrosyl-floxuridine and 5¢-L-phenylalanyl-L-tyrosyl-gemcitabine appeared in mouse plasma after the permeation of intestinal membrane and the first-pass effect, suggesting their potential for the development of oral dosage form for anti-cancer agents.

  20. The dipeptide monoester prodrugs of floxuridine and gemcitabine-feasibility of orally administrable nucleoside analogs.

    Science.gov (United States)

    Tsume, Yasuhiro; Borras Bermejo, Blanca; Amidon, Gordon L

    2014-01-27

    Dipeptide monoester prodrugs of floxuridine and gemcitabine were synthesized. Their chemical stability in buffers, enzymatic stability in cell homogenates, permeability in mouse intestinal membrane along with drug concentration in mouse plasma, and anti-proliferative activity in cancer cells were determined and compared to their parent drugs. Floxuridine prodrug was more enzymatically stable than floxuridine and the degradation from prodrug to parent drug works as the rate-limiting step. On the other hand, gemcitabine prodrug was less enzymatically stable than gemcitabine. Those dipeptide monoester prodrugs exhibited 2.4- to 48.7-fold higher uptake than their parent drugs in Caco-2, Panc-1, and AsPC-1 cells. Floxuridine and gemcitabine prodrugs showed superior permeability in mouse jejunum to their parent drugs and exhibited the higher drug concentration in plasma after in situ mouse perfusion. Cell proliferation assays in ductal pancreatic cancer cells, AsPC-1 and Panc-1, indicated that dipeptide prodrugs of floxuridine and gemcitabine were more potent than their parent drugs. The enhanced potency of nucleoside analogs was attributed to their improved membrane permeability. The prodrug forms of 5¢-L-phenylalanyl-l-tyrosyl-floxuridine and 5¢-L-phenylalanyl-L-tyrosyl-gemcitabine appeared in mouse plasma after the permeation of intestinal membrane and the first-pass effect, suggesting their potential for the development of oral dosage form for anti-cancer agents.

  1. The Dipeptide Monoester Prodrugs of Floxuridine and Gemcitabine—Feasibility of Orally Administrable Nucleoside Analogs

    Science.gov (United States)

    Tsume, Yasuhiro; Bermejo, Blanca Borras; Amidon, Gordon L.

    2014-01-01

    Dipeptide monoester prodrugs of floxuridine and gemcitabine were synthesized. Their chemical stability in buffers, enzymatic stability in cell homogenates, permeability in mouse intestinal membrane along with drug concentration in mouse plasma, and anti-proliferative activity in cancer cells were determined and compared to their parent drugs. Floxuridine prodrug was more enzymatically stable than floxuridine and the degradation from prodrug to parent drug works as the rate-limiting step. On the other hand, gemcitabine prodrug was less enzymatically stable than gemcitabine. Those dipeptide monoester prodrugs exhibited 2.4- to 48.7-fold higher uptake than their parent drugs in Caco-2, Panc-1, and AsPC-1 cells. Floxuridine and gemcitabine prodrugs showed superior permeability in mouse jejunum to their parent drugs and exhibited the higher drug concentration in plasma after in situ mouse perfusion. Cell proliferation assays in ductal pancreatic cancer cells, AsPC-1 and Panc-1, indicated that dipeptide prodrugs of floxuridine and gemcitabine were more potent than their parent drugs. The enhanced potency of nucleoside analogs was attributed to their improved membrane permeability. The prodrug forms of 5′-l-phenylalanyl-l-tyrosyl-floxuridine and 5′-l-phenylalanyl-l-tyrosyl-gemcitabine appeared in mouse plasma after the permeation of intestinal membrane and the first-pass effect, suggesting their potential for the development of oral dosage form for anti-cancer agents. PMID:24473270

  2. Preclinical studies of dendrimer prodrugs.

    Science.gov (United States)

    Kojima, Chie

    2015-01-01

    Dendrimers are synthetic macromolecules with well-defined structures bearing a wide variety of functional groups on their periphery. These groups can be used to conjugate bioactive molecules such as drugs, ligands and imaging agents. Dendrimer prodrugs can be used to improve the water solubility and pharmacokinetic properties of the corresponding free drugs. This article summarizes preclinical studies pertaining to the use of drug-dendrimer conjugates as dendrimer prodrugs for the treatments of various diseases, including cancer and inflammatory diseases. A wide range of anticancer drugs have been conjugated to dendrimers via biodegradable linkers. The side effects of the parent drugs can be markedly reduced using dendrimer prodrugs, with some drugs showing improved efficacy. Anti-inflammatory agents have also been conjugated to dendrimers and used to treat a number of inflammatory diseases. Drug-dendrimer conjugates are preferable to drug-dendrimer complexes, where the use of degradable linkers is critical to the release of the drug. Polyethylene glycol and/or ligands can be added to a dendrimer prodrug, which is useful for the targeting of affected tissues. Imaging probes can also be incorporated into dendrimer prodrugs for the simultaneous delivery of therapeutic and diagnostic agents as 'theranostics.'

  3. Substrate mediated enzyme prodrug therapy.

    Directory of Open Access Journals (Sweden)

    Betina Fejerskov

    Full Text Available In this report, we detail Substrate Mediated Enzyme Prodrug Therapy (SMEPT as a novel approach in drug delivery which relies on enzyme-functionalized cell culture substrates to achieve a localized conversion of benign prodrug(s into active therapeutics with subsequent delivery to adhering cells or adjacent tissues. For proof-of-concept SMEPT, we use surface adhered micro-structured physical hydrogels based on poly(vinyl alcohol, β-glucuronidase enzyme and glucuronide prodrugs. We demonstrate enzymatic activity mediated by the assembled hydrogel samples and illustrate arms of control over rate of release of model fluorescent cargo. SMEPT was not impaired by adhering cells and afforded facile time - and dose - dependent uptake of the in situ generated fluorescent cargo by hepatic cells, HepG2. With the use of a glucuronide derivative of an anticancer drug, SN-38, SMEPT afforded a decrease in cell viability to a level similar to that achieved using parent drug. Finally, dose response was achieved using SMEPT and administration of judiciously chosen concentration of SN-38 glucuronide prodrug thus revealing external control over drug delivery using drug eluting surface. We believe that this highly adaptable concept will find use in diverse biomedical applications, specifically surface mediated drug delivery and tissue engineering.

  4. Substrate-Competitive Activity-Based Profiling of Ester Prodrug Activating Enzymes.

    Science.gov (United States)

    Xu, Hao; Majmudar, Jaimeen D; Davda, Dahvid; Ghanakota, Phani; Kim, Ki H; Carlson, Heather A; Showalter, Hollis D; Martin, Brent R; Amidon, Gordon L

    2015-09-08

    Understanding the mechanistic basis of prodrug delivery and activation is critical for establishing species-specific prodrug sensitivities necessary for evaluating preclinical animal models and potential drug-drug interactions. Despite significant adoption of prodrug methodologies for enhanced pharmacokinetics, functional annotation of prodrug activating enzymes is laborious and often unaddressed. Activity-based protein profiling (ABPP) describes an emerging chemoproteomic approach to assay active site occupancy within a mechanistically similar enzyme class in native proteomes. The serine hydrolase enzyme family is broadly reactive with reporter-linked fluorophosphonates, which have shown to provide a mechanism-based covalent labeling strategy to assay the activation state and active site occupancy of cellular serine amidases, esterases, and thioesterases. Here we describe a modified ABPP approach using direct substrate competition to identify activating enzymes for an ethyl ester prodrug, the influenza neuraminidase inhibitor oseltamivir. Substrate-competitive ABPP analysis identified carboxylesterase 1 (CES1) as an oseltamivir-activating enzyme in intestinal cell homogenates. Saturating concentrations of oseltamivir lead to a four-fold reduction in the observed rate constant for CES1 inactivation by fluorophosphonates. WWL50, a reported carbamate inhibitor of mouse CES1, blocked oseltamivir hydrolysis activity in human cell homogenates, confirming CES1 is the primary prodrug activating enzyme for oseltamivir in human liver and intestinal cell lines. The related carbamate inhibitor WWL79 inhibited mouse but not human CES1, providing a series of probes for analyzing prodrug activation mechanisms in different preclinical models. Overall, we present a substrate-competitive activity-based profiling approach for broadly surveying candidate prodrug hydrolyzing enzymes and outline the kinetic parameters for activating enzyme discovery, ester prodrug design, and

  5. Substrate mediated enzyme prodrug therapy

    DEFF Research Database (Denmark)

    Fejerskov, Betina; Jarlstad Olesen, Morten T; Zelikin, Alexander N

    2017-01-01

    Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug administra......Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug...

  6. Pim kinases are upregulated during Epstein-Barr virus infection and enhance EBNA2 activity

    International Nuclear Information System (INIS)

    Rainio, Eeva-Marja; Ahlfors, Helena; Carter, Kara L.; Ruuska, Marja; Matikainen, Sampsa; Kieff, Elliott; Koskinen, Paeivi J.

    2005-01-01

    Latent Epstein-Barr virus (EBV) infection is strongly associated with B-cell proliferative diseases such as Burkitt's lymphoma. Here we show that the oncogenic serine/threonine kinases Pim-1 and Pim-2 enhance the activity of the viral transcriptional activator EBNA2. During EBV infection of primary B-lymphocytes, the mRNA expression levels of pim genes, especially of pim-2, are upregulated and remain elevated in latently infected B-cell lines. Thus, EBV-induced upregulation of Pim kinases and Pim-stimulated EBNA2 transcriptional activity may contribute to the ability of EBV to immortalize B-cells and predispose them to malignant growth

  7. Recent advances in macromolecular prodrugs

    DEFF Research Database (Denmark)

    Riber, Camilla Frich; Zelikin, Alexander N.

    2017-01-01

    Macromolecular prodrugs (MP) are high molar mass conjugates, typically carrying several copies of a drug or a drug combination, designed to optimize delivery of the drug, that is — its pharmacokinetics. From its advent several decades ago, design of MP has undergone significant development and es...

  8. Akt kinase C-terminal modifications control activation loop dephosphorylation and enhance insulin response.

    Science.gov (United States)

    Chan, Tung O; Zhang, Jin; Tiegs, Brian C; Blumhof, Brian; Yan, Linda; Keny, Nikhil; Penny, Morgan; Li, Xue; Pascal, John M; Armen, Roger S; Rodeck, Ulrich; Penn, Raymond B

    2015-10-01

    The Akt protein kinase, also known as protein kinase B, plays key roles in insulin receptor signalling and regulates cell growth, survival and metabolism. Recently, we described a mechanism to enhance Akt phosphorylation that restricts access of cellular phosphatases to the Akt activation loop (Thr(308) in Akt1 or protein kinase B isoform alpha) in an ATP-dependent manner. In the present paper, we describe a distinct mechanism to control Thr(308) dephosphorylation and thus Akt deactivation that depends on intramolecular interactions of Akt C-terminal sequences with its kinase domain. Modifications of amino acids surrounding the Akt1 C-terminal mTORC2 (mammalian target of rapamycin complex 2) phosphorylation site (Ser(473)) increased phosphatase resistance of the phosphorylated activation loop (pThr(308)) and amplified Akt phosphorylation. Furthermore, the phosphatase-resistant Akt was refractory to ceramide-dependent dephosphorylation and amplified insulin-dependent Thr(308) phosphorylation in a regulated fashion. Collectively, these results suggest that the Akt C-terminal hydrophobic groove is a target for the development of agents that enhance Akt phosphorylation by insulin. © 2015 Authors; published by Portland Press Limited.

  9. Trichinella spiralis infection enhances protein kinase C phosphorylation in guinea pig alveolar macrophages.

    Science.gov (United States)

    Dzik, J M; Zieliński, Z; Cieśla, J; Wałajtys-Rode, E

    2010-03-01

    To learn more about the signalling pathways involved in superoxide anion production in guinea pig alveolar macrophages, triggered by Trichinella spiralis infection, protein level and phosphorylation of mitogen activated protein (MAP) kinases and protein kinase C (PKC) were investigated. Infection with T. spiralis, the nematode having 'lung phase' during colonization of the host, enhances PKC phosphorylation in guinea pig alveolar macrophages. Isoenzymes beta and delta of PKC have been found significantly phosphorylated, although their location was not changed as a consequence of T. spiralis infection. Neither in macrophages from T. spiralis-infected guinea pig nor in platelet-activating factor (PAF)-stimulated macrophages from uninfected animals, participation of MAP kinases in respiratory burst activation was statistically significant. The parasite antigens seem to act through macrophage PAF receptors, transducing a signal for enhanced NADPH oxidase activity, as stimulating effect of newborn larvae homogenate on respiratory burst was abolished by specific PAF receptor antagonist CV 6209. A suppressive action of T. spiralis larvae on host alveolar macrophage innate immunological response was reflected by diminished protein level of ERK2 kinase and suppressed superoxide anion production, in spite of high level of PKC phosphorylation.

  10. Development and characterization of nanoparticulate formulation of a water soluble prodrug of dexamethasone by HIP complexation.

    Science.gov (United States)

    Gaudana, Ripal; Parenky, Ashwin; Vaishya, Ravi; Samanta, Swapan K; Mitra, Ashim K

    2011-01-01

    The objective of this study was to develop and characterize a nanoparticulate-based sustained release formulation of a water soluble dipeptide prodrug of dexamethasone, valine-valine-dexamethasone (VVD). Being hydrophilic in nature, it readily leaches out in the external aqueous medium and hence partitions poorly into the polymeric matrix resulting in minimal entrapment in nanoparticles. Hence, hydrophobic ion pairing (HIP) complexation of the prodrug was employed with dextran sulphate as a complexing polymer. A novel, solid in oil in water emulsion method was employed to encapsulate the prodrug in HIP complex form in poly(lactic-co-glycolic acid) matrix. Nanoparticles were characterized with respect to size, zeta potential, crystallinity of entrapped drug and surface morphology. A significant enhancement in the entrapment of the prodrug in nanoparticles was achieved. Finally, a simple yet novel method was developed which can also be applicable to encapsulate other charged hydrophilic molecules, such as peptides and proteins.

  11. In vitro evaluation of dendrimer prodrugs for oral drug delivery.

    Science.gov (United States)

    Najlah, Mohammad; Freeman, Sally; Attwood, David; D'Emanuele, Antony

    2007-05-04

    Dendrimer-based prodrugs were used to enhance the transepithelial permeability of naproxen, a low solubility model drug. The stability of the dendrimer-naproxen link was assessed. Naproxen was conjugated to G0 polyamidoamine (PAMAM) dendrimers either by an amide bond or an ester bond. The stability of G0 prodrugs was evaluated in 80% human plasma and 50% rat liver homogenate. The cytotoxicity of conjugates towards Caco-2 cells was determined and the transport of the conjugates across Caco-2 monolayers (37 degrees C) was reported. In addition, one lauroyl chain (L) was attached to the surface group of G0 PAMAM dendrimer of the diethylene glycol ester conjugate (G0-deg-NAP) to enhance permeability. The lactic ester conjugate, G0-lact-NAP, hydrolyzed slowly in 80% human plasma and in 50% rat liver homogenate (t(1/2)=180 min). G0-deg-NAP was hydrolyzed more rapidly in 80% human plasma (t(1/2)=51 min) and was rapidly cleaved in 50% liver homogenate (t(1/2)=4.7 min). The conjugates were non-toxic when exposed to Caco-2 cells for 3h. Permeability studies showed a significant enhancement in the transport of naproxen when conjugated to dendrimers; L-G0-deg-NAP yielding the highest permeability. Dendrimer-based prodrugs with appropriate linkers have potential as carriers for the oral delivery of low solubility drugs such as naproxen.

  12. Enhancement of myocardial regeneration through genetic engineering of cardiac progenitor cells expressing Pim-1 kinase.

    Science.gov (United States)

    Fischer, Kimberlee M; Cottage, Christopher T; Wu, Weitao; Din, Shabana; Gude, Natalie A; Avitabile, Daniele; Quijada, Pearl; Collins, Brett L; Fransioli, Jenna; Sussman, Mark A

    2009-11-24

    Despite numerous studies demonstrating the efficacy of cellular adoptive transfer for therapeutic myocardial regeneration, problems remain for donated cells with regard to survival, persistence, engraftment, and long-term benefits. This study redresses these concerns by enhancing the regenerative potential of adoptively transferred cardiac progenitor cells (CPCs) via genetic engineering to overexpress Pim-1, a cardioprotective kinase that enhances cell survival and proliferation. Intramyocardial injections of CPCs overexpressing Pim-1 were given to infarcted female mice. Animals were monitored over 4, 12, and 32 weeks to assess cardiac function and engraftment of Pim-1 CPCs with echocardiography, in vivo hemodynamics, and confocal imagery. CPCs overexpressing Pim-1 showed increased proliferation and expression of markers consistent with cardiogenic lineage commitment after dexamethasone exposure in vitro. Animals that received CPCs overexpressing Pim-1 also produced greater levels of cellular engraftment, persistence, and functional improvement relative to control CPCs up to 32 weeks after delivery. Salutary effects include reduction of infarct size, greater number of c-kit(+) cells, and increased vasculature in the damaged region. Myocardial repair is significantly enhanced by genetic engineering of CPCs with Pim-1 kinase. Ex vivo gene delivery to enhance cellular survival, proliferation, and regeneration may overcome current limitations of stem cell-based therapeutic approaches.

  13. PTP1B Inhibition Causes Rac1 Activation by Enhancing Receptor Tyrosine Kinase Signaling

    Directory of Open Access Journals (Sweden)

    Ayako Tsuchiya

    2014-04-01

    Full Text Available Background/Aims: The present study investigated the signaling pathway underlying Rac1 activation induced by the linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl-cyclopropyl]-octanoic acid (DCP-LA. Methods: Activity of protein tyrosine phosphatase 1B (PTP1B was assayed under cell-free conditions. Western blot was carried out to quantify phosphorylation of insulin receptor substrate-1 (IRS-1 and Akt in PC-12 cells. Rac1 activity was monitored in the föerster resonance energy transfer (FRET analysis using living and fixed PC-12 cells. Results: DCP-LA markedly suppressed PTP1B activity in a concentration (100 pM-100 µM-dependent manner. In the DCP-LA binding assay, fluorescein-conjugated DCP-LA produced a single fluorescent signal band at 60 kDa, corresponding to the molecule of PTP1B, and the signal was attenuated or abolished by co-treatment or pretreatment with non-conjugated DCP-LA. DCP-LA significantly enhanced nerve growth factor (NGF-stimulated phosphorylation of IRS-1 at Tyr1222 and Akt1/2 at Thr308/309 and Ser473/474 in PC-12 cells. In the FRET analysis, DCP-LA significantly enhanced NGF-stimulated Rac1 activation, which is abrogated by the phosphatidylinositol 3 kinase (PI3K inhibitor wortmannin, the 3-phosphoinositide-dependent protein kinase-1 (PDK1 inhibitor BX912, or the Akt inhibitor MK2206. Conclusion: The results of the present study show that DCP-LA-induced PTP1B inhibition, possibly through its direct binding, causes Rac1 activation by enhancing a pathway along a receptor tyrosine kinase (RTK/IRS-1/PI3K/Akt/Rac1 axis.

  14. SRC family kinase inhibitor SU6656 enhances antiangiogenic effect of irradiation

    International Nuclear Information System (INIS)

    Cuneo, Kyle C.; Geng Ling; Tan Jiahuai; Brousal, Jeffrey; Shinohara, Eric T.; Osusky, Katherine; Fu, Allie; Shyr, Yu; Wu Huiyun; Hallahan, Dennis E.

    2006-01-01

    Purpose: Src family kinases (SFK) have been identified as molecular targets. SU6656 is a small-molecule indolinone that specifically inhibits this family of kinases. Methods and Materials: Human umbilical vein endothelial cells were used to study the effects of SFK inhibition. Western blot analysis was performed to determine the effect of SFK inhibition on the PI3K/Akt pathway and caspase cleavage. Apoptosis was studied by propidium iodide staining of nuclei. Angiogenesis was examined using capillary tubule formation in Matrigel. Tumor response was further studied in vivo using Lewis lung carcinoma cells implanted into the dorsal skin fold of mice in the window model and in the hind limb in the tumor volume model. Results: Clonogenic survival of endothelial cells was decreased after the combined therapy of SU6656 and radiation compared with radiotherapy alone. Furthermore, SFK inhibition by SU6656 attenuated radiation-induced Akt phosphorylation and increased radiation-induced apoptosis and vascular endothelium destruction. In vivo, SU6656 administered before irradiation significantly enhanced radiation-induced destruction of blood vessels within the tumor windows and enhanced tumor growth delay when administered during fractionated irradiation. Conclusions: This study demonstrates the potential use of SFK inhibition to enhance the effects of ionizing radiation during radiotherapy

  15. The inhibitors of cyclin-dependent kinases and GSK-3β enhance osteoclastogenesis

    Directory of Open Access Journals (Sweden)

    Yosuke Akiba

    2016-03-01

    Full Text Available Osteoclasts are multinucleated cells with bone resorption activity that is crucial for bone remodeling. RANK‐RANKL (receptor activator of nuclear factor κB ligand signaling has been shown as a main signal pathway for osteoclast differentiation. However, the molecular mechanism and the factors regulating osteoclastogenesis remain to be fully understood. In this study, we performed a chemical genetic screen, and identified a Cdks/GSK-3β (cyclin-dependent kinases/glycogen synthase kinase 3β inhibitor, kenpaullone, and two Cdks inhibitors, olomoucine and roscovitine, all of which significantly enhance osteoclastogenesis of RAW264.7 cells by upregulating NFATc1 (nuclear factor of activated T cells, cytoplasmic 1 levels. We also determined that the all three compounds increase the number of osteoclast differentiated from murine bone marrow cells. Furthermore, the three inhibitors, especially kenpaullone, promoted maturation of cathepsin K, suggesting that the resorption activity of the resultant osteoclasts is also activated. Our findings indicate that inhibition of GSK-3β and/or Cdks enhance osteoclastogenesis by modulating the RANK–RANKL signaling pathway.

  16. Increasing oral absorption of polar neuraminidase inhibitors: a prodrug transporter approach applied to oseltamivir analogue.

    Science.gov (United States)

    Gupta, Deepak; Varghese Gupta, Sheeba; Dahan, Arik; Tsume, Yasuhiro; Hilfinger, John; Lee, Kyung-Dall; Amidon, Gordon L

    2013-02-04

    Poor oral absorption is one of the limiting factors in utilizing the full potential of polar antiviral agents. The neuraminidase target site requires a polar chemical structure for high affinity binding, thus limiting oral efficacy of many high affinity ligands. The aim of this study was to overcome this poor oral absorption barrier, utilizing prodrug to target the apical brush border peptide transporter 1 (PEPT1). Guanidine oseltamivir carboxylate (GOCarb) is a highly active polar antiviral agent with insufficient oral bioavailability (4%) to be an effective therapeutic agent. In this report we utilize a carrier-mediated targeted prodrug approach to improve the oral absorption of GOCarb. Acyloxy(alkyl) ester based amino acid linked prodrugs were synthesized and evaluated as potential substrates of mucosal transporters, e.g., PEPT1. Prodrugs were also evaluated for their chemical and enzymatic stability. PEPT1 transport studies included [(3)H]Gly-Sar uptake inhibition in Caco-2 cells and cellular uptake experiments using HeLa cells overexpressing PEPT1. The intestinal membrane permeabilities of the selected prodrugs and the parent drug were then evaluated for epithelial cell transport across Caco-2 monolayers, and in the in situ rat intestinal jejunal perfusion model. Prodrugs exhibited a pH dependent stability with higher stability at acidic pHs. Significant inhibition of uptake (IC(50) 30-fold increase in affinity compared to GOCarb. The l-valyl prodrug exhibited significant enhancement of uptake in PEPT1/HeLa cells and compared favorably with the well-absorbed valacyclovir. Transepithelial permeability across Caco-2 monolayers showed that these amino acid prodrugs have a 2-5-fold increase in permeability as compared to the parent drug and showed that the l-valyl prodrug (P(app) = 1.7 × 10(-6) cm/s) has the potential to be rapidly transported across the epithelial cell apical membrane. Significantly, only the parent drug (GOCarb) appeared in the basolateral

  17. A theranostic prodrug delivery system based on Pt(IV) conjugated nano-graphene oxide with synergistic effect to enhance the therapeutic efficacy of Pt drug.

    Science.gov (United States)

    Li, Jingwen; Lyv, Zhonglin; Li, Yanli; Liu, Huan; Wang, Jinkui; Zhan, Wenjun; Chen, Hong; Chen, Huabing; Li, Xinming

    2015-05-01

    Due to their high NIR-optical absorption and high specific surface area, graphene oxide and graphene oxide-based nanocomposites have great potential in both drug delivery and photothermal therapy. In the work reported herein we successfully integrate a Pt(IV) complex (c,c,t-[Pt(NH3)2Cl2(OH)2]), PEGylated nano-graphene oxide (PEG-NGO), and a cell apoptosis sensor into a single platform to generate a multifunctional nanocomposite (PEG-NGO-Pt) which shows potential for targeted drug delivery and combined photothermal-chemotherapy under near infrared laser irradiation (NIR), and real-time monitoring of its therapeutic efficacy. Non-invasive imaging using a fluorescent probe immobilized on the GO shows an enhanced therapeutic effect of PEG-NGO-Pt in cancer treatment via apoptosis and cell death. Due to the enhanced cytotoxicity of cisplatin and the highly specific tumor targeting of PEG-NGO-Pt at elevated temperatures, this nanocomposite displays a synergistic effect in improving the therapeutic efficacy of the Pt drug with complete destruction of tumors, no tumor recurrence and minimal systemic toxicity in comparison with chemotherapy or photothermal treatment alone, highlighting the advantageous effects of integrating Pt(IV) with GO for anticancer treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Contribution of canonical nonhomologous end joining to chromosomal rearrangements is enhanced by ATM kinase deficiency.

    Science.gov (United States)

    Bhargava, Ragini; Carson, Caree R; Lee, Gabriella; Stark, Jeremy M

    2017-01-24

    A likely mechanism of chromosomal rearrangement formation involves joining the ends from two different chromosomal double-strand breaks (DSBs). These events could potentially be mediated by either of two end-joining (EJ) repair pathways [canonical nonhomologous end joining (C-NHEJ) or alternative end joining (ALT-EJ)], which cause distinct rearrangement junction patterns. The relative role of these EJ pathways during rearrangement formation has remained controversial. Along these lines, we have tested whether the DNA damage response mediated by the Ataxia Telangiectasia Mutated (ATM) kinase may affect the relative influence of C-NHEJ vs. ALT-EJ on rearrangement formation. We developed a reporter in mouse cells for a 0.4-Mbp deletion rearrangement that is formed by EJ between two DSBs induced by the Cas9 endonuclease. We found that disruption of the ATM kinase causes an increase in the frequency of the rearrangement as well as a shift toward rearrangement junctions that show hallmarks of C-NHEJ. Furthermore, ATM suppresses rearrangement formation in an experimental condition, in which C-NHEJ is the predominant EJ repair event (i.e., expression of the 3' exonuclease Trex2). Finally, several C-NHEJ factors are required for the increase in rearrangement frequency caused by inhibition of the ATM kinase. We also examined ATM effectors and found that H2AX shows a similar influence as ATM, whereas the influence of ATM on this rearrangement seems independent of 53BP1. We suggest that the contribution of the C-NHEJ pathway to the formation of a 0.4-Mbp deletion rearrangement is enhanced in ATM-deficient cells.

  19. Enzastaurin (LY317615), a Protein Kinase C Beta Selective Inhibitor, Enhances Antiangiogenic Effect of Radiation

    International Nuclear Information System (INIS)

    Willey, Christopher D.; Xiao Dakai; Tu Tianxiang; Kim, Kwang Woon; Moretti, Luigi; Niermann, Kenneth J.; Tawtawy, Mohammed N.; Quarles, Chad C. Ph.D.; Lu Bo

    2010-01-01

    Purpose: Angiogenesis has generated interest in oncology because of its important role in cancer growth and progression, particularly when combined with cytotoxic therapies, such as radiotherapy. Among the numerous pathways influencing vascular growth and stability, inhibition of protein kinase B(Akt) or protein kinase C(PKC) can influence tumor blood vessels within tumor microvasculature. Therefore, we wanted to determine whether PKC inhibition could sensitize lung tumors to radiation. Methods and Materials: The combination of the selective PKCβ inhibitor Enzastaurin (ENZ, LY317615) and ionizing radiation were used in cell culture and a mouse model of lung cancer. Lung cancer cell lines and human umbilical vascular endothelial cells (HUVEC) were examined using immunoblotting, cytotoxic assays including cell proliferation and clonogenic assays, and Matrigel endothelial tubule formation. In vivo, H460 lung cancer xenografts were examined for tumor vasculature and proliferation using immunohistochemistry. Results: ENZ effectively radiosensitizes HUVEC within in vitro models. Furthermore, concurrent ENZ treatment of lung cancer xenografts enhanced radiation-induced destruction of tumor vasculature and proliferation by IHC. However, tumor growth delay was not enhanced with combination treatment compared with either treatment alone. Analysis of downstream effectors revealed that HUVEC and the lung cancer cell lines differed in their response to ENZ and radiation such that only HUVEC demonstrate phosphorylated S6 suppression, which is downstream of mTOR. When ENZ was combined with the mTOR inhibitor, rapamycin, in H460 lung cancer cells, radiosensitization was observed. Conclusion: PKC appears to be crucial for angiogenesis, and its inhibition by ENZ has potential to enhance radiotherapy in vivo.

  20. Poly(ethylene glycol-Prodrug Conjugates: Concept, Design, and Applications

    Directory of Open Access Journals (Sweden)

    Shashwat S. Banerjee

    2012-01-01

    Full Text Available Poly(ethylene glycol (PEG is the most widely used polymer in delivering anticancer drugs clinically. PEGylation (i.e., the covalent attachment of PEG of peptides proteins, drugs, and bioactives is known to enhance the aqueous solubility of hydrophobic drugs, prolong circulation time, minimize nonspecific uptake, and achieve specific tumor targetability through the enhanced permeability and retention effect. Numerous PEG-based therapeutics have been developed, and several have received market approval. A vast amount of clinical experience has been gained which has helped to design PEG prodrug conjugates with improved therapeutic efficacy and reduced systemic toxicity. However, more efforts in designing PEG-based prodrug conjugates are anticipated. In light of this, the current paper highlights the synthetic advances in PEG prodrug conjugation methodologies with varied bioactive components of clinical relevance. In addition, this paper discusses FDA-approved PEGylated delivery systems, their intended clinical applications, and formulations under clinical trials.

  1. Model prodrugs for the intestinal oligopeptide transporter

    DEFF Research Database (Denmark)

    Nielsen, C U; Andersen, R; Brodin, Birger

    2001-01-01

    The human intestinal di/tri-peptide carrier, hPepT1, has been suggested as a target for increasing intestinal transport of low permeability compounds by creating prodrugs designed for the transporter. Model ester prodrugs using the stabilized dipeptides D-Glu-Ala and D-Asp-Ala as pro...... with a pH of approximately 6.0, but still release the model drug at the intercellular and blood pH of approximately 7.4. Even though benzyl alcohol is not a low molecular weight drug molecule, these results indicate that the dipeptide prodrug principle is a promising drug delivery concept. However......, the physico-chemical properties such as electronegativity, solubility, and log P of the drug molecule may also have an influence on the potential of these kinds of prodrugs. The purpose of the present study is to investigate whether the model drug electronegativity, estimated as Taft substitution parameter...

  2. Inhibition of apoptosis signal-regulating kinase 1 alters the wound epidermis and enhances auricular cartilage regeneration.

    Directory of Open Access Journals (Sweden)

    Qian-Shi Zhang

    Full Text Available Why regeneration does not occur in mammals remains elusive. In lower vertebrates, epimorphic regeneration of the limb is directed by the wound epidermis, which controls blastema formation to promote regrowth of the appendage. Herein, we report that knockout (KO or inhibition of Apoptosis Signal-regulated Kinase-1 (ASK1, also known as mitogen-activated protein kinase kinase kinase 5 (MAP3K5, after full thickness ear punch in mice prolongs keratinocyte activation within the wound epidermis and promotes regeneration of auricular cartilage. Histological analysis showed the ASK1 KO ears displayed enhanced protein markers associated with blastema formation, hole closure and regeneration of auricular cartilage. At seven days after punch, the wound epidermis morphology was markedly different in the KO, showing a thickened stratum corneum with rounded cell morphology and a reduction of both the granular cell layer and decreased expression of filament aggregating protein. In addition, cytokeratin 6 was expressed in the stratum spinosum and granulosum. Topical application of inhibitors of ASK1 (NQDI-1, the upstream ASK1 activator, calcium activated mitogen kinase 2 (KN93, or the downstream target, c-Jun N-terminal kinase (SP600125 also resulted in enhanced regeneration; whereas inhibition of the other downstream target, the p38 α/β isoforms, (SB203580 had no effect. The results of this investigation indicate ASK1 inhibition prolongs keratinocyte and blastemal cell activation leading to ear regeneration.

  3. Inhibition of apoptosis signal-regulating kinase 1 alters the wound epidermis and enhances auricular cartilage regeneration

    Science.gov (United States)

    Zhang, Qian-Shi; Kurpad, Deepa S.; Mahoney, My G.; Steinbeck, Marla J.

    2017-01-01

    Why regeneration does not occur in mammals remains elusive. In lower vertebrates, epimorphic regeneration of the limb is directed by the wound epidermis, which controls blastema formation to promote regrowth of the appendage. Herein, we report that knockout (KO) or inhibition of Apoptosis Signal-regulated Kinase-1 (ASK1), also known as mitogen-activated protein kinase kinase kinase 5 (MAP3K5), after full thickness ear punch in mice prolongs keratinocyte activation within the wound epidermis and promotes regeneration of auricular cartilage. Histological analysis showed the ASK1 KO ears displayed enhanced protein markers associated with blastema formation, hole closure and regeneration of auricular cartilage. At seven days after punch, the wound epidermis morphology was markedly different in the KO, showing a thickened stratum corneum with rounded cell morphology and a reduction of both the granular cell layer and decreased expression of filament aggregating protein. In addition, cytokeratin 6 was expressed in the stratum spinosum and granulosum. Topical application of inhibitors of ASK1 (NQDI-1), the upstream ASK1 activator, calcium activated mitogen kinase 2 (KN93), or the downstream target, c-Jun N-terminal kinase (SP600125) also resulted in enhanced regeneration; whereas inhibition of the other downstream target, the p38 α/β isoforms, (SB203580) had no effect. The results of this investigation indicate ASK1 inhibition prolongs keratinocyte and blastemal cell activation leading to ear regeneration. PMID:29045420

  4. Anticancer activities of emetine prodrugs that are proteolytically activated by the prostate specific antigen (PSA) and evaluation of in vivo toxicity of emetine derivatives.

    Science.gov (United States)

    Akinboye, Emmanuel S; Rosen, Marc D; Bakare, Oladapo; Denmeade, Samuel R

    2017-12-15

    Emetine is a small molecule protein synthesis inhibitor that is toxic to all cell types and therefore suitable for complete killing of all types of heterogeneous cancer cells within a tumor. It becomes significantly inactive (non-toxic) when derivatized at its N-2' secondary amine. This provides a strategy for targeting emetine to cancerous tumor without killing normal cells. In this report, PSA activatable peptide prodrugs of emetine were synthesized. To overcome steric hindrances and enhance protease specific cleavage, a 2-stage prodrug activation process was needed to release emetine in cancer cells. In this 2-stage process, emetine prodrug intermediates are coupled to PSA peptide substrate (Ac-His-Ser-Ser-Lys-Leu-Gln) to obtain the full prodrug. Both prodrug intermediates 10 (Ala-Pro-PABC-Emetine) and 14 (Ser-Leu-PABC-Emetine) were evaluated for kinetics of hydrolysis to emetine and potency [Where PABC = p-aminobenzyloxycarbonyl]. While both intermediates quantitatively liberate emetine when incubated under appropriate conditions, upon coupling of PSA substrate to give the full prodrugs, only prodrug 16, the prodrug obtained from 14 was hydrolyzable by PSA. Cytotoxicity studies in PSA producing LNCaP and CWR22Rv1 confirm the activation of the prodrug by PSA with an IC 50 of 75 nM and 59 nM respectively. The cytotoxicity of 16 is significantly reduced in cell lines that do not produce PSA. Further, in vivo toxicity studies are done on these prodrugs and other derivatives of emetine. The results show the significance of conformational modulation in obtaining safe emetine prodrugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Nanostructured nanoparticles of self-assembled lipid pro-drugs as a route to improved chemotherapeutic agents

    Energy Technology Data Exchange (ETDEWEB)

    Sagnella, Sharon M.; Gong, Xiaojuan; Moghaddam, Minoo J.; Conn, Charlotte E.; Kimpton, Kathleen; Waddington, Lynne J.; Krodkiewska, Irena; Drummond, Calum J. (CSIRO/MSE); (CSIRO/LW)

    2014-09-24

    We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.

  6. Differentiation and fiber type-specific activity of a muscle creatine kinase intronic enhancer

    Directory of Open Access Journals (Sweden)

    Tai Phillip WL

    2011-07-01

    Full Text Available Abstract Background Hundreds of genes, including muscle creatine kinase (MCK, are differentially expressed in fast- and slow-twitch muscle fibers, but the fiber type-specific regulatory mechanisms are not well understood. Results Modulatory region 1 (MR1 is a 1-kb regulatory region within MCK intron 1 that is highly active in terminally differentiating skeletal myocytes in vitro. A MCK small intronic enhancer (MCK-SIE containing a paired E-box/myocyte enhancer factor 2 (MEF2 regulatory motif resides within MR1. The SIE's transcriptional activity equals that of the extensively characterized 206-bp MCK 5'-enhancer, but the MCK-SIE is flanked by regions that can repress its activity via the individual and combined effects of about 15 different but highly conserved 9- to 24-bp sequences. ChIP and ChIP-Seq analyses indicate that the SIE and the MCK 5'-enhancer are occupied by MyoD, myogenin and MEF2. Many other E-boxes located within or immediately adjacent to intron 1 are not occupied by MyoD or myogenin. Transgenic analysis of a 6.5-kb MCK genomic fragment containing the 5'-enhancer and proximal promoter plus the 3.2-kb intron 1, with and without MR1, indicates that MR1 is critical for MCK expression in slow- and intermediate-twitch muscle fibers (types I and IIa, respectively, but is not required for expression in fast-twitch muscle fibers (types IIb and IId. Conclusions In this study, we discovered that MR1 is critical for MCK expression in slow- and intermediate-twitch muscle fibers and that MR1's positive transcriptional activity depends on a paired E-box MEF2 site motif within a SIE. This is the first study to delineate the DNA controls for MCK expression in different skeletal muscle fiber types.

  7. Pharmacological Inhibition of Protein Kinase G1 Enhances Bone Formation by Human Skeletal Stem Cells Through Activation of RhoA-Akt Signaling

    DEFF Research Database (Denmark)

    Kermani, Abbas Jafari; Siersbaek, Majken S; Chen, Li

    2015-01-01

    for several malignant and nonmalignant conditions. We screened a library of kinase inhibitors to identify small molecules that enhance bone formation by human skeletal (stromal or mesenchymal) stem cells (hMSC). We identified H-8 (known to inhibit protein kinases A, C, and G) as a potent enhancer of ex vivo......Development of novel approaches to enhance bone regeneration is needed for efficient treatment of bone defects. Protein kinases play a key role in regulation of intracellular signal transduction pathways, and pharmacological targeting of protein kinases has led to development of novel treatments...

  8. Targeted Delivery of Deoxycytidine Kinase to Her2-Positive Cells Enhances the Efficacy of the Nucleoside Analog Fludarabine.

    Directory of Open Access Journals (Sweden)

    Sujatha P Koduvayur

    Full Text Available Cytotoxic drugs, such as nucleoside analogs and toxins, commonly suffer from off-target effects. One approach to mitigate this problem is to deliver the cytotoxic drug selectively to the intended site. While for toxins this can be achieved by conjugating the cell-killing moiety to a targeting moiety, it is not an option for nucleoside analogs, which rely on intracellular enzymes to convert them to their active triphosphorylated form. To overcome this limitation, and achieve site-targeted activation of nucleoside analogs, we fused the coding region of a prodrug-activating enzyme, deoxycytidine kinase (dCK, to affinity reagents that bind to the Her2 cell surface protein. We evaluated dCK fusions to an anti-Her2 affibody and Designed Ankyrin Repeat Protein (DARPin for their ability to kill cancer cells by promoting the activation of the nucleoside analog fludarabine. Cell staining and flow cytometry experiments with three Her2 positive cancer cell lines (BT-474-JB, JIMT-1 and SK-OV-3 indicate dCK fusions binding and cellular internalization. In contrast, these reagents bind only weakly to the Her2 negative cell line, MCF-7. Cell proliferation assays indicate that SK-OV-3 and BT-474-JB cell lines exhibit significantly reduced proliferation rates when treated with targeting-module fused dCK and fludarabine, compared to fludarabine alone. These findings demonstrate that we have succeeded in delivering active dCK into the Her2-positive cells, thereby increasing the activation of fludarabine, which ultimately reduces the dose of nucleoside analog needed for cell killing. This strategy may help establish the therapeutic index required to differentiate between healthy tissues and cancer cells.

  9. Ocular Pharmacokinetics of Acyclovir Amino Acid Ester Prodrugs in the Anterior Chamber: Evaluation of Their Utility in Treating Ocular HSV Infections

    Science.gov (United States)

    Katragadda, Suresh; Gunda, Sriram; Hariharan, Sudharshan; Mitra, Ashim K.

    2008-01-01

    Purpose To evaluate in vivo corneal absorption of the amino acid prodrugs of acyclovir (ACV) using a topical well model and microdialysis in rabbits. Methods Stability of L-Alanine-ACV (AACV), L-Serine-ACV (SACV), L-Isoleucine-ACV (IACV), γ-Glutamate-ACV (EACV) and L-Valine-ACV (VACV) prodrugs was evaluated in various ocular tissues. Dose dependent toxicity of these prodrugs was also examined in rabbit primary corneal epithelial cell culture (rPCEC) using 96-well based cell proliferation assay. In vivo ocular bioavailability of these compounds was also evaluated with a combination of topical well infusion and aqueous humor microdialysis techniques. Results Among the amino acid ester prodrugs, SACV was most stable in aqueous humor. Enzymatic degradation of EACV was the least compared to all other prodrugs. Cellular toxicity of all the prodrugs was significantly less compared to trifluorothymidine (TFT) at 5mM. Absorption rate constants of all the compounds were found to be lower than the elimination rate constants. All the prodrugs showed similar terminal elimination rate constants (λz). SACV and VACV exhibited approximately two fold increase in area under the curve (AUC) relative to ACV (p cornea at varying rates (ka) thereby leading to varying extents (AUC). The amino acid ester prodrug, SACV owing to its enhanced stability, comparable AUC, and high concentration at last time point (Clast) seems to be a promising candidate for the treatment of ocular HSV infections. PMID:18472234

  10. Hypoxia-targeting antitumor prodrugs and photosensitizers

    International Nuclear Information System (INIS)

    Zhang Zhouen; Nishimoto, S.I.

    2006-01-01

    Tumor hypoxia has been identified as a key subject for tumor therapy, since hypoxic tumor cells show resistance to treatment of tumor tissues by radiotherapy, chemotherapy and phototherapy. For improvement of tumor radiotherapy, we have proposed a series of radiation-activated prodrugs that could selectively release antitumor agent 5-fluorouracil or 5-fluorodeoxyuridine under hypoxic conditions. Recently, we attempted to develop two families of novel hypoxia-targeting antitumor agents, considering that tumor-hypoxic environment is favorable to biological and photochemical reductions. The first family of prodrugs was derived from camptothecin as a potent topoisomerase I inhibitor and several bioreductive motifs. These prodrugs could be activated by NADPH-cytochrome P450 reductase or DT-diaphorase to release free camptothecin, and thereby showed hypoxia-selective cytotoxictiy towards tumor cells. These prodrugs were also applicable to the real-time monitoring of activation and antitumor effect by fluorometry. Furthermore, the camptothecin-bioreductive motif conjugates was confirmed to show an oxygen-independent DAN photocleaving activity, which could overcome a drawback of back electron transfer occurring in the photosensitized one-electron oxidation of DNA. Thus, these camptothecin derivatives could be useful to both chemotherapy and phototherapy for hypoxic tumor cells. The second family of prodrugs harnessed UV light for cancer therapy, incorporating the antitumor agent 5-fluorourcil and the photolabile 2-nitrobenzyl chromophores. The attachment of a tumor-homing cyclic peptide CNGRC was also employed to construct the prototype of tumor-targeting photoactiaved antitumor prodrug. These novel prodrugs released high yield of 5-fluorourcil upon UV irradiation at λ ex =365 nm, while being quite stable in the dark. The photoactivation mechanism was also clarified by means of nanosecond laser flash photolysis. (authors)

  11. Enhanced Arabidopsis pattern-triggered immunity by overexpression of cysteine-rich receptor-like kinases.

    Science.gov (United States)

    Yeh, Yu-Hung; Chang, Yu-Hsien; Huang, Pin-Yao; Huang, Jing-Bo; Zimmerli, Laurent

    2015-01-01

    Upon recognition of microbe-associated molecular patterns (MAMPs) such as the bacterial flagellin (or the derived peptide flg22) by pattern-recognition receptors (PRRs) such as the FLAGELLIN SENSING2 (FLS2), plants activate the pattern-triggered immunity (PTI) response. The L-type lectin receptor kinase-VI.2 (LecRK-VI.2) is a positive regulator of Arabidopsis thaliana PTI. Cysteine-rich receptor-like kinases (CRKs) possess two copies of the C-X8-C-X2-C (DUF26) motif in their extracellular domains and are thought to be involved in plant stress resistance, but data about CRK functions are scarce. Here, we show that Arabidopsis overexpressing the LecRK-VI.2-responsive CRK4, CRK6, and CRK36 demonstrated an enhanced PTI response and were resistant to virulent bacteria Pseudomonas syringae pv. tomato DC3000. Notably, the flg22-triggered oxidative burst was primed in CRK4, CRK6, and CRK36 transgenics and up-regulation of the PTI-responsive gene FLG22-INDUCED RECEPTOR-LIKE 1 (FRK1) was potentiated upon flg22 treatment in CRK4 and CRK6 overexpression lines or constitutively increased by CRK36 overexpression. PTI-mediated callose deposition was not affected by overexpression of CRK4 and CRK6, while CRK36 overexpression lines demonstrated constitutive accumulation of callose. In addition, Pst DC3000-mediated stomatal reopening was blocked in CRK4 and CRK36 overexpression lines, while overexpression of CRK6 induced constitutive stomatal closure suggesting a strengthening of stomatal immunity. Finally, bimolecular fluorescence complementation and co-immunoprecipitation analyses in Arabidopsis protoplasts suggested that the plasma membrane localized CRK4, CRK6, and CRK36 associate with the PRR FLS2. Association with FLS2 and the observation that overexpression of CRK4, CRK6, and CRK36 boosts specific PTI outputs and resistance to bacteria suggest a role for these CRKs in Arabidopsis innate immunity.

  12. Enhanced transdermal delivery of ketobemidone with prodrugs

    DEFF Research Database (Denmark)

    Hansen, L.B.; Fullerton, A.; Christrup, Lona Louring

    1992-01-01

    were observed for the ketobemidone esters from 20% w/v solutions in ethanol and ethanol-water (3:1 and 1:1 v/v) vehicles. The esters were rapidly hydrolyzed to the parent drug in the presence of skin enzymes and only from ketobemidone was detected in the receptor phase. The study demonstrates...

  13. Redox-responsive core cross-linked prodrug micelles prepared by click chemistry for pH-triggered doxorubicin delivery

    Directory of Open Access Journals (Sweden)

    X. T. Cao

    2017-10-01

    Full Text Available A pH-triggered drug delivery system of degradable core cross-linked (CCL prodrug micelles was prepared by click chemistry. Doxorubicin conjugated block copolymers of azido functional poly(ethylene oxide-b-poly(glycidyl methacrylate were synthesized by the combination of RAFT polymerization, epoxide ring-opening reaction, and acid-cleavable hydrazone linkages. The CCL prodrug micelles were produced by the reaction of dipropargyl 3,3′-dithiodipropionate and dipropargyl adipate cross-linking agents with the azido groups of the micellar core via alkyne-azide click reaction, which were denoted as CCL/SS and CCL/noSS, respectively. The TEM images of CCL/SS prodrug micelles showed a spherical shape with the average diameter of 61.0 nm from water, and the shape was maintained with an increased diameter upon dilution with 5-fold DMF. The high DOX conjugation efficiency was 88.4%. In contrast to a very slow DOX release from CCL/SS prodrug micelles under the physiological condition (pH 7.4, the drug release is much faster (90% at pH 5.0 and 10 mM of GSH after 96 h. The cytotoxicity test and confocal laser scanning microscopy analysis revealed that CCL/SS prodrug micelles had much enhanced intracellular drug release capability in HepG2 cells than CCL/noSS prodrug micelles.

  14. [In vitro metabolism of fenbendazole prodrug].

    Science.gov (United States)

    Wen, Ai-Dan; Duan, Li-Ping; Liu, Cong-Shan; Tao, Yi; Xue, Jian; Wu, Ning-Bo; Jiang, Bin; Zhang, Hao-Bing

    2013-02-01

    Synthesized fenbendazole prodrug N-methoxycarbonyl-N'-(2-nitro-4-phenylthiophenyl) thiourea (MPT) was analyzed in vitro in artificial gastric juice, intestinal juice and mouse liver homogenate model by using HPLC method, and metabolic curve was then generated. MPT was tested against Echinococcus granulosus protoscolices in vitro. The result showed that MPT could be metabolized in the three biological media, and to the active compound fenbendazole in liver homogenate, with a metabolic rate of 7.92%. Besides, the prodrug showed a weak activity against E. granulosus protoscolices with a mortality of 45.9%.

  15. Troxacitabine prodrugs for pancreatic cancer

    NARCIS (Netherlands)

    Adema, A. D.; Radi, M.; Daft, J.; Narayanasamy, J.; Hoebe, E. K.; Alexander, L. E.; Chu, C. K.; Peters, G. J.

    2007-01-01

    Troxacitabine is a cytotoxic deoxycytidine analogue with an unnatural L-configuration, which is activated by deoxycytidine kinase (dCK). The configuration is responsible for differences in the uptake and metabolism of troxacitabine compared to other deoxynucleoside analogues. The main drawback in

  16. Long-Acting Diclofenac Ester Prodrugs for Joint Injection

    DEFF Research Database (Denmark)

    Mertz, Nina; Larsen, Susan Weng; Kristensen, Jesper

    2016-01-01

    A prodrug approach for local and sustained diclofenac action after injection into joints based on ester prodrugs having a pH-dependent solubility is presented. Inherent ester prodrug properties influencing the duration of action include their pH-dependent solubility and charge state, as well...... as susceptibility to undergo esterase facilitated hydrolysis. In this study, physicochemical properties and pH rate profiles of 3 diclofenac ester prodrugs differing with respect to the spacer carbon chain length between the drug and the imidazole-based promoiety were determined and a rate equation for prodrug...... degradation in aqueous solution in the pH range 1-10 was derived. In the pH range 6-10, the prodrugs were subject to parallel degradation to yield diclofenac and an indolinone derivative. The prodrug degradation was found to be about 6-fold faster in 80% (vol/vol) human plasma as compared to 80% (vol...

  17. Exchange Protein Activated by cAMP Enhances Long-Term Memory Formation Independent of Protein Kinase A

    Science.gov (United States)

    Ma, Nan; Abel, Ted; Hernandez, Pepe J.

    2009-01-01

    It is well established that cAMP signaling within neurons plays a major role in the formation of long-term memories--signaling thought to proceed through protein kinase A (PKA). However, here we show that exchange protein activated by cAMP (Epac) is able to enhance the formation of long-term memory in the hippocampus and appears to do so…

  18. Protein kinase A activation enhances β-catenin transcriptional activity through nuclear localization to PML bodies.

    Directory of Open Access Journals (Sweden)

    Mei Zhang

    Full Text Available The Protein Kinase A (PKA and Wnt signaling cascades are fundamental pathways involved in cellular development and maintenance. In the osteoblast lineage, these pathways have been demonstrated functionally to be essential for the production of mineralized bone. Evidence for PKA-Wnt crosstalk has been reported both during tumorigenesis and during organogenesis, and the nature of the interaction is thought to rely on tissue and cell context. In this manuscript, we analyzed bone tumors arising from mice with activated PKA caused by mutation of the PKA regulatory subunit Prkar1a. In primary cells from these tumors, we observed relocalization of β-catenin to intranuclear punctuate structures, which were identified as PML bodies. Cellular redistribution of β-catenin could be recapitulated by pharmacologic activation of PKA. Using 3T3-E1 pre-osteoblasts as a model system, we found that PKA phosphorylation sites on β-catenin were required for nuclear re-localization. Further, β-catenin's transport to the nucleus was accompanied by an increase in canonical Wnt-dependent transcription, which also required the PKA sites. PKA-Wnt crosstalk in the cells was bi-directional, including enhanced interactions between β-catenin and the cAMP-responsive element binding protein (CREB and transcriptional crosstalk between the Wnt and PKA signaling pathways. Increases in canonical Wnt/β-catenin signaling were associated with a decrease in the activity of the non-canonical Wnt/Ror2 pathway, which has been shown to antagonize canonical Wnt signaling. Taken together, this study provides a new understanding of the complex regulation of the subcellular distribution of β-catenin and its differential protein-protein interaction that can be modulated by PKA signaling.

  19. Overexpression of a novel endogenous NADH kinase in Aspergillus nidulans enhances growth

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Grotkjær, Thomas; Hofmann, Gerald

    2009-01-01

    .7.1.86) has been identified. The enzyme has a predicted molecular weight of 49 kDa. We characterised the role of this NADH kinase by genomic integration of the putative gene AN8837.2 under a strong constitutive promoter. The physiological effects of overexpressed NADH kinase in combination with different...... yield on glucose and the maximum specific growth rate increased from 0.47 g/g and 0.22 h(-1) (wild type) to 0.54 g/g and 0.26 h(-1) (NADH kinase overexpressed), respectively. The results suggest that overexpression of NADH kinase improves the growth efficiency of the cell by increasing the access...

  20. Inducible Activation of ERK5 MAP Kinase Enhances Adult Neurogenesis in the Olfactory Bulb and Improves Olfactory Function

    Science.gov (United States)

    Wang, Wenbin; Lu, Song; Li, Tan; Pan, Yung-Wei; Zou, Junhui; Abel, Glen M.; Xu, Lihong; Storm, Daniel R.

    2015-01-01

    Recent discoveries have suggested that adult neurogenesis in the subventricular zone (SVZ) and olfactory bulb (OB) may be required for at least some forms of olfactory behavior in mice. However, it is unclear whether conditional and selective enhancement of adult neurogenesis by genetic approaches is sufficient to improve olfactory function under physiological conditions or after injury. Furthermore, specific signaling mechanisms regulating adult neurogenesis in the SVZ/OB are not fully defined. We previously reported that ERK5, a MAP kinase selectively expressed in the neurogenic regions of the adult brain, plays a critical role in adult neurogenesis in the SVZ/OB. Using a site-specific knock-in mouse model, we report here that inducible and targeted activation of the endogenous ERK5 in adult neural stem/progenitor cells enhances adult neurogenesis in the OB by increasing cell survival and neuronal differentiation. This conditional ERK5 activation also improves short-term olfactory memory and odor-cued associative olfactory learning under normal physiological conditions. Furthermore, these mice show enhanced recovery of olfactory function and have more adult-born neurons after a zinc sulfate-induced lesion of the main olfactory epithelium. We conclude that ERK5 MAP kinase is an important endogenous signaling pathway regulating adult neurogenesis in the SVZ/OB, and that conditional activation of endogenous ERK5 is sufficient to enhance adult neurogenesis in the OB thereby improving olfactory function both under normal conditions and after injury. PMID:25995470

  1. Improvement of buccal delivery of morphine using the prodrug approach

    DEFF Research Database (Denmark)

    Christrup, Lona Louring; Jørgensen, A.; Christensen, C.B.

    1997-01-01

    relationship to the lipophilicity of the compounds. In the in vitro studies the optimal permeation was achieved for the prodrug morphine-3-propionate having a log P value of approximately 0.7. In contrast to that optimal in vivo absorption was obtained for the prodrug morphine-3-acetate having a log P value...... Improved by using ester prodrugs with higher lipophilicity than morphine itself. However, the enzymatic stability of the prodrugs in saliva also play an important role for the overall improvement in absorption properties....

  2. Insulin resistance enhances the mitogen-activated protein kinase signaling pathway in ovarian granulosa cells.

    Directory of Open Access Journals (Sweden)

    Linghui Kong

    Full Text Available The ovary is the main regulator of female fertility. Granulosa cell dysfunction may be involved in various reproductive endocrine disorders. Here we investigated the effect of insulin resistance on the metabolism and function of ovarian granulosa cells, and dissected the functional status of the mitogen-activated protein kinase signaling pathway in these cells. Our data showed that dexamethasone-induced insulin resistance in mouse granulosa cells reduced insulin sensitivity, accompanied with an increase in phosphorylation of p44/42 mitogen-activated protein kinase. Furthermore, up-regulation of cytochrome P450 subfamily 17 and testosterone and down-regulation of progesterone were observed in insulin-resistant mouse granulosa cells. Inhibition of p44/42 mitogen-activated protein kinase after induction of insulin resistance in mouse granulosa cells decreased phosphorylation of p44/42 mitogen-activated protein kinase, downregulated cytochrome P450 subfamily 17 and lowered progesterone production. This insulin resistance cell model can successfully demonstrate certain mechanisms such as hyperandrogenism, which may inspire a new strategy for treating reproductive endocrine disorders by regulating cell signaling pathways.

  3. Combining the pan-aurora kinase inhibitor AMG 900 with histone deacetylase inhibitors enhances antitumor activity in prostate cancer

    International Nuclear Information System (INIS)

    Paller, Channing J; Wissing, Michel D; Mendonca, Janet; Sharma, Anup; Kim, Eugene; Kim, Hea-Soo; Kortenhorst, Madeleine S Q; Gerber, Stephanie; Rosen, Marc; Shaikh, Faraz; Zahurak, Marianna L; Rudek, Michelle A; Hammers, Hans; Rudin, Charles M; Carducci, Michael A; Kachhap, Sushant K

    2014-01-01

    Histone deacetylase inhibitors (HDACIs) are being tested in clinical trials for the treatment of solid tumors. While most studies have focused on the reexpression of silenced tumor suppressor genes, a number of genes/pathways are downregulated by HDACIs. This provides opportunities for combination therapy: agents that further disable these pathways through inhibition of residual gene function are speculated to enhance cell death in combination with HDACIs. A previous study from our group indicated that mitotic checkpoint kinases such as PLK1 and Aurora A are downregulated by HDACIs. We used in vitro and in vivo xenograft models of prostate cancer (PCA) to test whether combination of HDACIs with the pan-aurora kinase inhibitor AMG 900 can synergistically or additively kill PCA cells. AMG 900 and HDACIs synergistically decreased cell proliferation activity and clonogenic survival in DU-145, LNCaP, and PC3 PCA cell lines compared to single-agent treatment. Cellular senescence, polyploidy, and apoptosis was significantly increased in all cell lines after combination treatment. In vivo xenograft studies indicated decreased tumor growth and decreased aurora B kinase activity in mice treated with low-dose AMG 900 and vorinostat compared to either agent alone. Pharmacodynamics was assessed by scoring for phosphorylated histone H3 through immunofluorescence. Our results indicate that combination treatment with low doses of AMG 900 and HDACIs could be a promising therapy for future clinical trials against PCA

  4. Effective gene silencing activity of prodrug-type 2'-O-methyldithiomethyl siRNA compared with non-prodrug-type 2'-O-methyl siRNA.

    Science.gov (United States)

    Hayashi, Junsuke; Nishigaki, Misa; Ochi, Yosuke; Wada, Shun-Ichi; Wada, Fumito; Nakagawa, Osamu; Obika, Satoshi; Harada-Shiba, Mariko; Urata, Hidehito

    2018-07-01

    Small interfering RNAs (siRNAs) are an active agent to induce gene silencing and they have been studied for becoming a biological and therapeutic tool. Various 2'-O-modified RNAs have been extensively studied to improve the nuclease resistance. However, the 2'-O-modified siRNA activities were often decreased by modification, since the bulky 2'-O-modifications inhibit to form a RNA-induced silencing complex (RISC). We developed novel prodrug-type 2'-O-methyldithiomethyl (MDTM) siRNA, which is converted into natural siRNA in an intracellular reducing environment. Prodrug-type 2'-O-MDTM siRNAs modified at the 5'-end side including 5'-end nucleotide and the seed region of the antisense strand exhibited much stronger gene silencing effect than non-prodrug-type 2'-O-methyl (2'-O-Me) siRNAs. Furthermore, the resistances for nuclease digestion of siRNAs were actually enhanced by 2'-O-MDTM modifications. Our results indicate that 2'-O-MDTM modifications improve the stability of siRNA in serum and they are able to be introduced at any positions of siRNA. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. The Design and Evaluation of an l-Dopa–Lazabemide Prodrug for the Treatment of Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Monique Hoon

    2017-11-01

    Full Text Available l-Dopa, the metabolic precursor of dopamine, is the treatment of choice for the symptomatic relief of the advanced stages of Parkinson’s disease. The oral bioavailability of l-dopa, however, is only about 10% to 30%, and less than 1% of the oral dose is estimated to reach the brain unchanged. l-Dopa’s physicochemical properties are responsible for its poor bioavailability, short half-life and the wide range of inter- and intrapatient variations of plasma levels. An l-dopa–lazabemide prodrug is proposed to overcome the problems associated with l-dopa absorption. Lazabemide is a monoamine oxidase (MAO-B inhibitor, a class of compounds that slows the depletion of dopamine stores in Parkinson’s disease and elevates dopamine levels produced by exogenously administered l-dopa. l-Dopa was linked at the carboxylate with the primary aminyl functional group of lazabemide via an amide, a strategy which is anticipated to protect l-dopa against peripheral decarboxylation and possibly also enhance the membrane permeability of the prodrug. Selected physicochemical and biochemical properties of the prodrug were determined and included lipophilicity (logD, solubility, passive diffusion permeability, pKa, chemical and metabolic stability as well as cytotoxicity. Although oral and i.p. treatment of mice with the prodrug did not result in enhanced striatal dopamine levels, 3,4-dihydroxyphenylacetic acid (DOPAC levels were significantly depressed compared to saline, l-dopa and carbidopa/l-dopa treatment. Based on the results, further preclinical evaluation of the l-dopa–lazabemide prodrug should be undertaken with the aim of discovering prodrugs that may be advanced to the clinical stages of development.

  6. Tomato thymidine kinase is subject to inefficient TTP feedback regulation

    DEFF Research Database (Denmark)

    Larsen, Nicolai Balle; Munch-Petersen, Birgitte; Piskur, Jure

    2014-01-01

    A promising suicide gene therapy system to treat gliomas has been reported: the thymidine kinase 1 from tomato (toTK1) combined with the nucleoside analog pro-drug zidovudine (azidothymidine, AZT), which is known to penetrate the blood–brain barrier. Transduction with toTK1 has been found to effi...

  7. Two weeks of metformin treatment enhances mitochondrial respiration in skeletal muscle of AMPK kinase dead but not wild type mice

    DEFF Research Database (Denmark)

    Kristensen, Jonas Møller; Larsen, Steen; Helge, Jørn Wulff

    2013-01-01

    signaling. We investigated this by two weeks of oral metformin treatment of muscle specific kinase dead a(2) (KD) AMPK mice and wild type (WT) littermates. We measured mitochondrial respiration and protein activity and expressions of key enzymes involved in mitochondrial carbohydrate and fat metabolism...... and oxidative phosphorylation. Mitochondrial respiration, HAD and CS activity, PDH and complex I-V and cytochrome c protein expression were all reduced in AMPK KD compared to WT tibialis anterior muscles. Surprisingly, metformin treatment only enhanced respiration in AMPK KD mice and thereby rescued...... the respiration defect compared to the WT mice. Metformin did not influence protein activities or expressions in either WT or AMPK KD mice.We conclude that two weeks of in vivo metformin treatment enhances mitochondrial respiration in the mitochondrial deficient AMPK KD but not WT mice. The improvement seems...

  8. Inducible activation of ERK5 MAP kinase enhances adult neurogenesis in the olfactory bulb and improves olfactory function.

    Science.gov (United States)

    Wang, Wenbin; Lu, Song; Li, Tan; Pan, Yung-Wei; Zou, Junhui; Abel, Glen M; Xu, Lihong; Storm, Daniel R; Xia, Zhengui

    2015-05-20

    Recent discoveries have suggested that adult neurogenesis in the subventricular zone (SVZ) and olfactory bulb (OB) may be required for at least some forms of olfactory behavior in mice. However, it is unclear whether conditional and selective enhancement of adult neurogenesis by genetic approaches is sufficient to improve olfactory function under physiological conditions or after injury. Furthermore, specific signaling mechanisms regulating adult neurogenesis in the SVZ/OB are not fully defined. We previously reported that ERK5, a MAP kinase selectively expressed in the neurogenic regions of the adult brain, plays a critical role in adult neurogenesis in the SVZ/OB. Using a site-specific knock-in mouse model, we report here that inducible and targeted activation of the endogenous ERK5 in adult neural stem/progenitor cells enhances adult neurogenesis in the OB by increasing cell survival and neuronal differentiation. This conditional ERK5 activation also improves short-term olfactory memory and odor-cued associative olfactory learning under normal physiological conditions. Furthermore, these mice show enhanced recovery of olfactory function and have more adult-born neurons after a zinc sulfate-induced lesion of the main olfactory epithelium. We conclude that ERK5 MAP kinase is an important endogenous signaling pathway regulating adult neurogenesis in the SVZ/OB, and that conditional activation of endogenous ERK5 is sufficient to enhance adult neurogenesis in the OB thereby improving olfactory function both under normal conditions and after injury. Copyright © 2015 the authors 0270-6474/15/357833-17$15.00/0.

  9. Blocking the eIF2α kinase (PKR) enhances positive and negative forms of cortex-dependent taste memory.

    Science.gov (United States)

    Stern, Elad; Chinnakkaruppan, Adaikkan; David, Orit; Sonenberg, Nahum; Rosenblum, Kobi

    2013-02-06

    Age-associated memory deterioration (and the decline in ability to acquire new information) is one of the major diseases of our era. Cognitive enhancement can be achieved by using psycho-stimulants, such as caffeine or nicotine, but very little is known about drugs that can enhance the consolidation phase of memories in the cortex, the brain structure considered to store, at least partially, long-term memories. We used cortex-dependent taste-learning paradigms to test the hypothesis that pharmacological manipulation of the translation initiation eIF2α, which plays a role in hippocampus-dependent memory, can enhance positive or negative forms of taste memories. We found that dephosphorylation (Ser51) of eIF2α, specifically in the cortex, is both correlated with and necessary for normal memory consolidation. To reduce eIF2α phosphorylation and improve memory consolidation, we pharmacologically inhibited one of the eIF2α kinases, PKR, which is known to be involved in brain aging and Alzheimer's disease. Systemic or local microinjection of PKR inhibitor to the gustatory cortex enhanced both positive and negative forms of taste memory in rats and mice. Our results provide clear evidence that PKR plays a major role in cortex-dependent memory consolidation and, therefore, that pharmacological inhibition of PKR is a potential target for drugs to enhance cognition.

  10. Prodrugs for the Treatment of Neglected Diseases

    Directory of Open Access Journals (Sweden)

    Lorena Blau

    2007-03-01

    Full Text Available Recently, World Health Organization (WHO and Medicins San Frontieres (MSF proposed a classification of diseases as global, neglected and extremely neglected. Global diseases, such as cancer, cardiovascular and mental (CNS diseases represent the targets of the majority of the R&D efforts of pharmaceutical companies. Neglected diseases affect millions of people in the world yet existing drug therapy is limited and often inappropriate. Furthermore, extremely neglected diseases affect people living under miserable conditions who barely have access to the bare necessities for survival. Most of these diseases are excluded from the goals of the R&D programs in the pharmaceutical industry and therefore fall outside the pharmaceutical market. About 14 million people, mainly in developing countries, die each year from infectious diseases. From 1975 to 1999, 1393 new drugs were approved yet only 1% were for the treatment of neglected diseases [3]. These numbers have not changed until now, so in those countries there is an urgent need for the design and synthesis of new drugs and in this area the prodrug approach is a very interesting field. It provides, among other effects, activity improvements and toxicity decreases for current and new drugs, improving market availability. It is worth noting that it is essential in drug design to save time and money, and prodrug approaches can be considered of high interest in this respect. The present review covers 20 years of research on the design of prodrugs for the treatment of neglected and extremely neglected diseases such as Chagas’ disease (American trypanosomiasis, sleeping sickness (African trypanosomiasis, malaria, sickle cell disease, tuberculosis, leishmaniasis and schistosomiasis.

  11. All-trans-retinoic acid enhances apoptosis induction by tyrosine kinase inhibitors in the eosinophilic leukemia-derived EoL-1 cell line.

    Science.gov (United States)

    Robert, Carine; Apàti, Agota; Chomienne, Christine; Papp, Béla

    2008-02-01

    Imatinib and retinoids induce apoptosis in FIP1L1/PDGFRalpha-positive EoL-1 leukemia cells. Although imatinib induces complete remission in most FIP1L1/PDGFRalpha-positive patients, response to imatinib is sometimes suboptimal. In order to enhance the potency of the molecularly targeted therapy of eosinophilic leukemia, we investigated the effect of retinoids combined with tyrosine kinase inhibitors on EoL-1 cells. We demonstrate that retinoids combined with tyrosine kinase inhibitors lead to enhanced apoptosis induction in EoL-1 cells. Our results suggest that tyrosine kinase inhibitors combined with retinoids may constitute a valuable therapeutic approach for sensitive neoplasias that may display enhanced anti-leukemic potency when compared to single drug treatments.

  12. Targeting Polo-Like Kinase 1 Enhances Radiation Efficacy for Head-and-Neck Squamous Cell Carcinoma

    International Nuclear Information System (INIS)

    Gerster, Kate; Shi Wei; Ng, Benjamin; Yue Shijun; Ito, Emma; Waldron, John; Gilbert, Ralph; Liu Feifei

    2010-01-01

    Purpose: To investigate the efficacy of targeting polo-like kinase 1 (Plk1) combined with ionizing radiotherapy (RT) for head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Polo-like kinase 1 messenger ribonucleic acid (mRNA) was targeted by small interfering RNA (siRNA) transfection into the FaDu HNSCC cell line; reduction was confirmed using quantitative real-time polymerase chain reaction. The cellular effects were assessed using [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl) -2-(4-sulfophenyl)-2H-tetrazolium], clonogenic, flow cytometric, and caspase assays. In vivo efficacy of siPlk1 was evaluated using mouse xenograft models. Results: Small interfering Plk1 significantly decreased Plk1 mRNA expression, while also increasing cyclin B1 and p21(Waf1/CIP1) mRNA levels after 24 h. This depletion resulted in a time-dependent increase in FaDu cytotoxicity, which was enhanced by the addition of RT. Flow cytometric and caspase assays demonstrated progressive apoptosis, DNA double-strand breaks (γ-H2AX), G2/M arrest, and activation of caspases 3 and 7. Implantation of siPlk1-treated FaDu cells in severe combined immunodeficient mice delayed tumor formation, and systemic administration of siPlk1 inhibited tumor growth enhanced by RT. Conclusions: These data demonstrate the suitability of Plk1 as a potential therapeutic target for HNSCC, because Plk1 depletion resulted in significant cytotoxicity in vitro and abrogated tumor-forming potential in vivo. The effects of Plk1 depletion were enhanced with the addition of RT, indicating that Plk1 represents an important potential radiation sensitizer for HNSCC.

  13. Effect of Simvastatin Prodrug on Experimental Periodontitis.

    Science.gov (United States)

    Bradley, Aaron D; Zhang, Yijia; Jia, Zhenshan; Zhao, Gang; Wang, Xiaobei; Pranke, Laura; Schmid, Marian J; Wang, Dong; Reinhardt, Richard A

    2016-05-01

    Local application of statins has shown potential in preventing and regenerating bone loss associated with experimental periodontitis. This study evaluates the effect of a novel simvastatin (SIM) prodrug (capable of delivering high doses to periodontitis inflammatory lesion and cells) on experimental periodontitis bone loss and inflammation. Forty mature female Sprague Dawley rats were subjected to ligature-induced experimental periodontitis between maxillary first and second molars (M1-M2). Equal groups were treated with three weekly doses of: 1) prodrug carrier alone (mPEG); 2) 0.5 mg SIM dose equivalent in carrier (SIM/SIM-mPEG); 3) 1.0 mg SIM/SIM-mPEG; 4) 1.5 mg SIM/SIM-mPEG; or 5) ligature alone. Contralateral molars served as unmanipulated controls. Four weeks after initiation of periodontitis, animals were euthanized, the M1-M2 interproximal was evaluated with microcomputed tomography and histology, and data were analyzed with one-way analysis of variance. Ligature alone caused a mean bone loss of 1.01 ± 0.06 mm from the cemento-enamel junction, whereas all doses of SIM/SIM-mPEG reduced bone loss, especially 1.5 mg SIM/SIM-mPEG (0.68 ± 0.05 mm, P periodontitis bone loss and inflammation in rats.

  14. Enhancement of radioresponse by combined treatment with flavopiridol, a cycline dependent kinase (CDK) inhibitor, in oral cancer cells

    International Nuclear Information System (INIS)

    Mihara, Mariko; Mano, Takamitsu; Ueyama, Yoshiya; Shintani, Satoru; Li, Syunnann; Klosek, S.; Hamakawa, Hiroyuki

    2005-01-01

    Cyclin dependent kinases (CDKs) play a pivotal role in cell cycle regulation. Flavopiridol is known to potently inhibit such CDKs as CDK1, CDK2, CDK4, CDK7. We already reported that flavopiridol inhibited the growth of oral squamous cell carcinoma (OSCC) cells and induced apoptosis in OSCC cells. In the present study, we investigated whether the treatment with flavopiridol improves the response to radiosensitivity in OSCC cell lines. In an in vitro study, there was a cooperative antiproliferative effect of combined treatment with flavopiridol and radiation in OSCC cell lines. Tumor xenograft studies demonstrated that the combination of flavopiridol and radiation caused growth inhibition and tumor regression of well-established OSCC tumor in athymic mice. Overall, we concluded that flavopiridol enhances tumor radioresponse and it is considered a suitable candidate drug in the treatment of oral cancer. (author)

  15. Photo-triggered fluorescent theranostic prodrugs as DNA alkylating agents for mechlorethamine release and spatiotemporal monitoring.

    Science.gov (United States)

    Cao, Yanting; Pan, Rong; Xuan, Weimin; Wei, Yongyi; Liu, Kejian; Zhou, Jiahong; Wang, Wei

    2015-06-28

    We describe a new theranostic strategy for selective delivery and spatiotemporal monitoring of mechlorethamine, a DNA alkylating agent. A photo-responsive prodrug is designed and composed of a photolabile o-nitrophenylethyl group, a DNA alkylating mechlorethamine drug and a coumarin fluorophore. Masking of the "N" in mechlorethamine in a positively charged state in the prodrug renders it inactive, non-toxic, selective and non-fluorescent. Indeed, the stable prodrug shows negligible cytotoxicity towards normal cells with and without UV activation and is completely non-fluorescent. However, upon photo-irradiation, the active mechlorethamine is released and induces efficient DNA cross-links, accompanied by a strong fluorescence enhancement (152 fold). Furthermore, DNA cross-linking activity from the release can be transformed into anticancer activity observed in in vitro studies of tumor cells. Importantly, the drug release progress and the movement can be conveniently monitored by fluorescence spectroscopy. The mechanistic study proves that the DNA cross-linking activity is mainly due to the release of DNA alkylating mechlorethamine. Altogether, the studies show the power of the theranostic strategy for efficient therapy in cancer treatment.

  16. In Vitro and In Vivo Evaluation of Microparticulate Drug Delivery Systems Composed of Macromolecular Prodrugs

    Directory of Open Access Journals (Sweden)

    Yoshiharu Machida

    2008-08-01

    Full Text Available Macromolecular prodrugs are very useful systems for achieving controlled drug release and drug targeting. In particular, various macromolecule-antitumor drug conjugates enhance the effectiveness and improve the toxic side effects. Also, polymeric micro- and nanoparticles have been actively examined and their in vivo behaviors elucidated, and it has been realized that their particle characteristics are very useful to control drug behavior. Recently, researches based on the combination of the concepts of macromolecular prodrugs and micro- or nanoparticles have been reported, although they are limited. Macromolecular prodrugs enable drugs to be released at a certain controlled release rate based on the features of the macromolecule-drug linkage. Micro- and nanoparticles can control in vivo behavior based on their size, surface charge and surface structure. These merits are expected for systems produced by the combination of each concept. In this review, several micro- or nanoparticles composed of macromolecule-drug conjugates are described for their preparation, in vitro properties and/or in vivo behavior.

  17. Activated Integrin-Linked Kinase Negatively Regulates Muscle Cell Enhancement Factor 2C in C2C12 Cells

    Directory of Open Access Journals (Sweden)

    Zhenguo Dong

    2015-01-01

    Full Text Available Our previous study reported that muscle cell enhancement factor 2C (MEF2C was fully activated after inhibition of the phosphorylation activity of integrin-linked kinase (ILK in the skeletal muscle cells of goats. It enhanced the binding of promoter or enhancer of transcription factor related to proliferation of muscle cells and then regulated the expression of these genes. In the present investigation, we explored whether ILK activation depended on PI3K to regulate the phosphorylation and transcriptional activity of MEF2C during C2C12 cell proliferation. We inhibited PI3K activity in C2C12 with LY294002 and then found that ILK phosphorylation levels and MEF2C phosphorylation were decreased and that MCK mRNA expression was suppressed significantly. After inhibiting ILK phosphorylation activity with Cpd22 and ILK-shRNA, we found MEF2C phosphorylation activity and MCK mRNA expression were increased extremely significantly. In the presence of Cpd22, PI3K activity inhibition increased MEF2C phosphorylation and MCK mRNA expression indistinctively. We conclude that ILK negatively and independently of PI3K regulated MEF2C phosphorylation activity and MCK mRNA expression in C2C12 cells. The results provide new ideas for the study of classical signaling pathway of PI3K-ILK-related proteins and transcription factors.

  18. Dipeptidyl peptidase IV as a potential target for selective prodrug activation and chemotherapeutic action in cancers.

    Science.gov (United States)

    Dahan, Arik; Wolk, Omri; Yang, Peihua; Mittal, Sachin; Wu, Zhiqian; Landowski, Christopher P; Amidon, Gordon L

    2014-12-01

    The efficacy of chemotherapeutic drugs is often offset by severe side effects attributable to poor selectivity and toxicity to normal cells. Recently, the enzyme dipeptidyl peptidase IV (DPPIV) was considered as a potential target for the delivery of chemotherapeutic drugs. The purpose of this study was to investigate the feasibility of targeting chemotherapeutic drugs to DPPIV as a strategy to enhance their specificity. The expression profile of DPPIV was obtained for seven cancer cell lines using DNA microarray data from the DTP database, and was validated by RT-PCR. A prodrug was then synthesized by linking the cytotoxic drug melphalan to a proline-glycine dipeptide moiety, followed by hydrolysis studies in the seven cell lines with a standard substrate, as well as the glycyl-prolyl-melphalan (GP-Mel). Lastly, cell proliferation studies were carried out to demonstrate enzyme-dependent activation of the candidate prodrug. The relative RT-PCR expression levels of DPPIV in the cancer cell lines exhibited linear correlation with U95Av2 Affymetrix data (r(2) = 0.94), and with specific activity of a standard substrate, glycine-proline-p-nitroanilide (r(2) = 0.96). The significantly higher antiproliferative activity of GP-Mel in Caco-2 cells (GI₅₀ = 261 μM) compared to that in SK-MEL-5 cells (GI₅₀ = 807 μM) was consistent with the 9-fold higher specific activity of the prodrug in Caco-2 cells (5.14 pmol/min/μg protein) compared to SK-MEL-5 cells (0.68 pmol/min/μg protein) and with DPPIV expression levels in these cells. Our results demonstrate the great potential to exploit DPPIV as a prodrug activating enzyme for efficient chemotherapeutic drug targeting.

  19. Small Molecules Targeting Ataxia Telangiectasia and Rad3-Related (ATR) Kinase: An Emerging way to Enhance Existing Cancer Therapy

    Czech Academy of Sciences Publication Activity Database

    Andrs, M.; Korábečný, J.; Nepovimova, E.; Jun, D.; Hodný, Zdeněk; Kuca, K.

    2016-01-01

    Roč. 16, č. 3 (2016), s. 200-208 ISSN 1568-0096 Institutional support: RVO:68378050 Keywords : Ataxia telangiectasia and Rad3-related kinase (ATR) * cancer * chemosensitization * DNA damage response * phosphatidylinositol 3-kinase-related protein kinases (PIKK) * radiosensitization * synthetic lethality Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.992, year: 2016

  20. Phosphoglycerate kinase enhanced immunity of the whole cell of Streptococcus agalactiae in tilapia, Oreochromis niloticus.

    Science.gov (United States)

    Wang, Yi-Ting; Huang, Hsing-Yen; Tsai, Ming-An; Wang, Pei-Chi; Jiang, Bo-Huang; Chen, Shih-Chu

    2014-12-01

    Streptococcus agalactiae is a Gram-positive bacterium and a severe aquaculture pathogen that can infect a wide range of warmwater fish species. The outer-surface proteins in bacterial pathogens play an important role in pathogenesis. We evaluated the immunogenicity of two of the identified surface proteins namely phosphoglycerate kinase (PGK) and ornithine carbamoyl-transferase (OCT). PGK and OCT were over-expressed and purified from Escherichia coli and used as the subunit vaccines in tilapia. Tilapia immunized with the S. agalactiae modified bacteria vaccine (whole cell preparations with recombinant PGK and OCT proteins) individually were tested for the efficacy. OCT and PGK combined with WC had a higher survival rate. A high-level protection and significant specific antibody responses against S. agalactiae challenge was observed upon the vaccinated tilapia with the purified PGK protein and S. agalactiae whole cells. The specific antibody titer against S. agalactiae antigen suggested that increased antibody titers were correlated with post-challenge survival rate. Il-1β expression profile was higher in PGK + WC-treated group. Tnf-α expression in the PGK + WC group was significantly increased. Taken together, our results suggested the combinations of recombinant protein and whole cell may elicit immune responses that reach greater protection than that of individual S. agalactiae components. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Interaction of dipeptide prodrugs of saquinavir with multidrug resistance protein-2 (MRP-2): evasion of MRP-2 mediated efflux.

    Science.gov (United States)

    Jain, Ritesh; Agarwal, Sheetal; Mandava, Nanda Kishore; Sheng, Ye; Mitra, Ashim K

    2008-10-01

    Saquinavir (SQV), the first protease inhibitor approved by FDA to treat HIV-1 infection. This drug is a well-known substrate for multidrug resistance protein-2 (MRP-2). The objective of this study was to investigate whether derivatization of SQV to dipeptide prodrugs, valine-valine-saquinavir (Val-Val-SQV) and glycine-valine-saquinavir (Gly-Val-SQV), targeting peptide transporter can circumvent MRP-2 mediated efflux. Uptake and transport studies were carried out across MDCKII-MRP2 cell monolayers to investigate the interaction of SQV and its prodrugs with MRP-2. In situ single pass intestinal perfusion experiments in rat jejunum were performed to calculate intestinal absorption rate constants and permeabilities of SQV, Val-Val-SQV and Gly-Val-SQV. Uptake studies demonstrated that the prodrugs have significantly lower interaction with MRP-2 relative to SQV. Transepithelial transport of Val-Val-SQV and Gly-Val-SQV across MDCKII-MRP2 cells exhibited an enhanced absorptive flux and reduced secretory flux as compared to SQV. Intestinal perfusion studies revealed that synthesized prodrugs have higher intestinal permeabilities relative to SQV. Enhanced absorption of Val-Val-SQV and Gly-Val-SQV relative to SQV can be attributed to their translocation by the peptide transporter in the jejunum. In the presence of MK-571, a MRP family inhibitor, there was a significant increase in the permeabilities of SQV and Gly-Val-SQV indicating that these compounds are probably substrates for MRP-2. However, there was no change in the permeability of Val-Val-SQV with MK-571 indicating lack of any interaction of Val-Val-SQV with MRP-2. In conclusion, peptide transporter targeted prodrug modification of MRP-2 substrates may lead to shielding of these drug molecules from MRP-2 efflux pumps.

  2. Novel Polymeric Prodrugs of Valproic Acid as Anti- Epilepsy Drugs ...

    African Journals Online (AJOL)

    Epilepsy Drugs: Synthesis, Characterization and In-vitro ... The release of VPA from polymeric prodrugs was studied using cellophane ... pharmacokinetics and accessibility in market [8]. ..... between the drug and polymer chain can affect.

  3. HTLV-1 Tax protein recruitment into IKKε and TBK1 kinase complexes enhances IFN-I expression.

    Science.gov (United States)

    Diani, Erica; Avesani, Francesca; Bergamo, Elisa; Cremonese, Giorgia; Bertazzoni, Umberto; Romanelli, Maria Grazia

    2015-02-01

    The Tax protein expressed by human T-cell leukemia virus type 1 (HTLV-1) plays a pivotal role in the deregulation of cellular pathways involved in the immune response, inflammation, cell survival, and cancer. Many of these effects derive from Tax multiple interactions with host factors, including the subunits of the IKK-complex that are required for NF-κB activation. IKKɛ and TBK1 are two IKK-related kinases that allow the phosphorylation of interferon regulatory factors that trigger IFN type I gene expression. We observed that IKKɛ and TBK1 recruit Tax into cellular immunocomplexes. We also found that TRAF3, which regulates cell receptor signaling effectors, forms complexes with Tax. Transactivation analyses revealed that expression of Tax, in presence of IKKɛ and TBK1, enhances IFN-β promoter activity, whereas the activation of NF-κB promoter is not modified. We propose that Tax may be recruited into the TBK1/IKKɛ complexes as a scaffolding-adaptor protein that enhances IFN-I gene expression. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Brain-derived neurotrophic factor is produced by skeletal muscle cells in response to contraction and enhances fat oxidation via activation of AMP-activated protein kinase

    DEFF Research Database (Denmark)

    Matthews, V B; Åström, Maj-Brit; Chan, M H S

    2009-01-01

    C12 skeletal muscle cells were electrically stimulated to mimic contraction. L6 myotubes and isolated rat extensor digitorum longus muscles were treated with BDNF and phosphorylation of the proteins AMP-activated protein kinase (AMPK) (Thr(172)) and acetyl coenzyme A carboxylase beta (ACCbeta) (Ser...... kinase (p44/42 Thr(202)/Tyr(204)) phosphorylation in these muscles. In addition, phosphorylation of ACCbeta was markedly elevated in the Bdnf electroporated muscles. CONCLUSIONS/INTERPRETATION: These data identify BDNF as a contraction-inducible protein in skeletal muscle that is capable of enhancing...

  5. Effects of vehicles and prodrug properties and their interactions on the delivery of 6-mercaptopurine through skin: bisacyloxymethyl-6-mercaptopurine prodrugs.

    Science.gov (United States)

    Waranis, R P; Sloan, K B

    1987-08-01

    A series of S6,9-bisacyloxymethyl-6-mercaptopurine (6,9-bis-6-MP) prodrug derivatives was synthesized and characterized. The solubilities of the derivatives in solvents (vehicles), which exhibited a wide range of polarities from water to oleic acid, were measured. The abilities of the prodrugs to deliver 6-mercaptopurine (6-MP) from the vehicles have also been determined, and experimental fluxes and permeability coefficients (Kp) have been calculated for a large number of prodrug: vehicle combinations. Generally the best prodrugs of the series in terms of delivering 6-MP, regardless of the vehicle, were the first two members--the bisacetyl- and the bispropionyloxymethyl-6-mercaptopurine prodrugs. This result has been attributed mainly to the increased water solubility of these two prodrugs compared with that of 6-MP and the other prodrugs, since all of the prodrugs are much more lipid soluble than 6-MP. For three vehicles--isopropyl myristate, propylene glycol, and water--there was a good correlation between log experimental Kp for the delivery of 6-MP by the prodrugs from those vehicles and the theoretical solubility parameters of the prodrugs. The stabilities of the bisacetyl-(2), bisproprionyl-(3), and bisbutyryloxymethyl-6-mercaptopurine (4) derivatives were determined in buffer and in buffer containing enzymes leached from the dermis. Prodrug 2 was more stable than 3 or 4 in the buffer containing the enzymes, while 4 was more stable than 2 or 3 in the plain buffer.

  6. Inhibition of Glycogen Synthase Kinase-3ß Enhances Cognitive Recovery after Stroke: The Role of TAK1

    Science.gov (United States)

    Venna, Venugopal Reddy; Benashski, Sharon E.; Chauhan, Anjali; McCullough, Louise D.

    2015-01-01

    Memory deficits are common among stroke survivors. Identifying neuroprotective agents that can prevent memory impairment or improve memory recovery is a vital area of research. Glycogen synthase kinase-3ß (GSK-3ß) is involved in several essential intracellular signaling pathways. Unlike many other kinases, GSK-3ß is active only when…

  7. Prodrugs activated by reactive oxygen species for use in the treatment of inflammatory diseases and cancer

    DEFF Research Database (Denmark)

    2018-01-01

    Prodrugs activated predominantly or exclusively in inflammatory tissue, more particularly prodrugs of methotrexate and derivatives thereof, which are selectively activated by Reactive Oxygen Species (ROS) in inflammatory tissues associated with cancer and inflammatory diseases, as well as method...

  8. 1-Arylsulfonyl-2-(Pyridylmethylsulfinyl) Benzimidazoles as New Proton Pump Inhibitor Prodrugs

    Science.gov (United States)

    Shin, Jai Moo; Sachs, George; Cho, Young-moon; Garst, Michael

    2010-01-01

    New arylsulfonyl proton pump inhibitor (PPI) prodrug forms were synthesized. These prodrugs provided longer residence time of an effective PPI plasma concentration, resulting in better gastric acid inhibition. PMID:20032890

  9. Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor.

    Science.gov (United States)

    Ojeda, Norma B; Royals, Thomas P; Alexander, Barbara T

    2013-04-01

    This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg(-1)·min(-1)) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats.

  10. Nicotine shifts the temporal activation of hippocampal protein kinase A and extracellular signal-regulated kinase 1/2 to enhance long-term, but not short-term, hippocampus-dependent memory.

    Science.gov (United States)

    Gould, Thomas J; Wilkinson, Derek S; Yildirim, Emre; Poole, Rachel L F; Leach, Prescott T; Simmons, Steven J

    2014-03-01

    Acute nicotine enhances hippocampus-dependent learning through nicotine binding to β2-containing nicotinic acetylcholine receptors (nAChRs), but it is unclear if nicotine is targeting processes involved in short-term memory (STM) leading to a strong long-term memory (LTM) or directly targeting LTM. In addition, the molecular mechanisms involved in the effects of nicotine on learning are unknown. Previous research indicates that protein kinase A (PKA), extracellular signal-regulated kinase 1/2 (ERK1/2), and protein synthesis are crucial for LTM. Therefore, the present study examined the effects of nicotine on STM and LTM and the involvement of PKA, ERK1/2, and protein synthesis in the nicotine-induced enhancement of hippocampus-dependent contextual learning in C57BL/6J mice. The protein synthesis inhibitor anisomycin impaired contextual conditioning assessed at 4 h but not 2 h post-training, delineating time points for STM (2 h) and LTM (4 h and beyond). Nicotine enhanced contextual conditioning at 4, 8, and 24 h but not 2 h post-training, indicating nicotine specifically enhances LTM but not STM. Furthermore, nicotine did not rescue deficits in contextual conditioning produced by anisomycin, suggesting that the nicotine enhancement of contextual conditioning occurs through a protein synthesis-dependent mechanism. In addition, inhibition of dorsal hippocampal PKA activity blocked the effect of acute nicotine on learning, and nicotine shifted the timing of learning-related PKA and ERK1/2 activity in the dorsal and ventral hippocampus. Thus, the present results suggest that nicotine specifically enhances LTM through altering the timing of PKA and ERK1/2 signaling in the hippocampus, and suggests that the timing of PKA and ERK1/2 activity could contribute to the strength of memories. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Colon-specific prodrugs of 5-radioiodo-2'-deoxyuridine

    International Nuclear Information System (INIS)

    Baranowska-Kortylewicz, J.; Kortylewicz, Z.P.; Hoffman, D.; Winoto, A.; Lai, J.; Dalrymple, G.V.

    1996-01-01

    Two glycoside-based prodrugs, 125 IUdR-5'-β-D-glucopyranoside and 125 IUdR-5'-β-D-galactopyranoside, were synthesized. This selection was dictated by the abundance of appropriate enzymes in the GI tract of mice and similar levels of β-D-glycosidases in human and rodent large intestine. Studies to establish the ability of colonic microflora to release 125 IUdR were conducted in vitro and in Swiss Webster mice. Both prodrugs released 125 IUdR in the presence of the corresponding enzymes or the GI content homogenates in vitro, and in vivo. Luminal enzymes in the proximal and distal small intestine in mice degraded less than 10% of each prodrug whereas enzymes from the colonic/caecal lumen of mice released nearly 100% of 125 IUdR. 125 IUdR freed by bacterial glycosidases was stable in the GI content. No significant amounts of other metabolites or deiodination products were observed. Total radioactivity recovered as by-products was less than 10%. The efflux of prodrugs from the GI tract after oral administration in mice was slow and limited. Unlike 125 IUdR, prodrugs were not dehalogenated in vivo as indicated by biodistribution and imaging studies. (orig.)

  12. Mechanism of action for the cytotoxic effects of the nitric oxide prodrug JS-K in murine erythroleukemia cells.

    Science.gov (United States)

    Kaczmarek, Monika Z; Holland, Ryan J; Lavanier, Stephen A; Troxler, Jami A; Fesenkova, Valentyna I; Hanson, Charlotte A; Cmarik, Joan L; Saavedra, Joseph E; Keefer, Larry K; Ruscetti, Sandra K

    2014-03-01

    The nitric oxide (NO) prodrug JS-K, a promising anti-cancer agent, consists of a diazeniumdiolate group necessary for the release of NO as well as an arylating ring. In this study, we research the mechanism by which JS-K kills a murine erythroleukemia cell line and determine the roles of NO and arylation in the process. Our studies indicate that JS-K inhibits the PI 3-kinase/Akt and MAP kinase pathways. This correlates with the activation of the tumor suppressor FoxO3a and increased expression of various caspases, leading to apoptosis. The arylating capability of JS-K appears to be sufficient for inducing these biological effects. Overall, these data suggest that JS-K kills tumor cells by arylating and inactivating signaling molecules that block the activation of a tumor suppressor. Published by Elsevier Ltd.

  13. Dysregulated miR34a/diacylglycerol kinase ζ interaction enhances T-cell activation in acquired aplastic anemia.

    Science.gov (United States)

    Sun, Yuan-Xin; Li, Hui; Feng, Qi; Li, Xin; Yu, Ying-Yi; Zhou, Li-Wei; Gao, Yan; Li, Guo-Sheng; Ren, Juan; Ma, Chun-Hong; Gao, Cheng-Jiang; Peng, Jun

    2017-01-24

    Acquired aplastic anemia is an idiopathic paradigm of human bone marrow failure syndrome, which involves active destruction of hematopoietic stem cells and progenitors by cytotoxic T cells in the bone marrow. Aberrant expression of microRNAs in T cells has been shown to lead to development of certain autoimmune diseases. In the present study, we performed a microarray analysis of miRNA expression in bone marrow CD3+ T cells from patients with aplastic anemia and healthy controls. Overexpression of miR34a and underexpression of its target gene diacylglycerol kinase (DGK) ζ in bone marrow mononuclear cells were validated in 41 patients and associated with the severity of aplastic anemia. Further, the level of miR34a was higher in naïve T cells from patients than from controls. The role of miR34a and DGKζ in aplastic anemia was investigated in a murine model of immune-mediated bone marrow failure using miR34a-/- mice. After T-cell receptor stimulation in vitro, lymph node T cells from miR34a-/- mice demonstrated reduced activation and proliferation accompanied with a less profound down-regulation of DGKζ expression and decreased ERK phosphorylation compared to those from wild-type C57BL6 control mice. Infusion of 5 × 106 miR34a-/- lymph node T cells into sublethally irradiated CB6F1 recipients led to increased Lin-Sca1+CD117+ cells and less vigorous expansion of CD8+ T cells than injection of same number of wild-type lymph node cells. Our study demonstrates that the miR34a/DGKζ dysregulation enhances T-cell activation in aplastic anemia and targeting miR34a may represent a novel molecular therapeutic approach for patients with aplastic anemia.

  14. Enhanced casein kinase II activity during mouse embryogenesis. Identification of a 110-kDa phosphoprotein as the major phosphorylation product in mouse embryos and Krebs II mouse ascites tumor cells

    DEFF Research Database (Denmark)

    Schneider, H R; Reichert, G H; Issinger, O G

    1986-01-01

    Mouse embryos at various stages of development were used to study the relationship of protein kinase activities with normal embryogenesis. Casein kinase II (CKII) activity in developing mouse embryos shows a 3-4-fold activity increase at day 12 of gestation. Together with the CKII activity...... mouse tumour cells also show an enhanced CKII activity. Here too, a 110-kDa phosphoprotein was the major phosphoryl acceptor. Partial proteolytic digestion shows that both proteins are identical. Other protein kinases tested (cAMP- and cGMP-dependent protein kinases) only show a basal level of enzyme...

  15. The Prodrug Approach: A Successful Tool for Improving Drug Solubility

    Directory of Open Access Journals (Sweden)

    Daniela Hartmann Jornada

    2015-12-01

    Full Text Available Prodrug design is a widely known molecular modification strategy that aims to optimize the physicochemical and pharmacological properties of drugs to improve their solubility and pharmacokinetic features and decrease their toxicity. A lack of solubility is one of the main obstacles to drug development. This review aims to describe recent advances in the improvement of solubility via the prodrug approach. The main chemical carriers and examples of successful strategies will be discussed, highlighting the advances of this field in the last ten years.

  16. Clickable prodrugs bearing potent and hydrolytically cleavable nicotinamide phosphoribosyltransferase inhibitors

    Directory of Open Access Journals (Sweden)

    Sadrerafi K

    2018-04-01

    Full Text Available Keivan Sadrerafi, Emilia O Mason, Mark W Lee Jr Department of Chemistry, University of Missouri, Columbia, MO, USA Purpose: Our previous study indicated that carborane containing small-molecule 1-(hydroxymethyl-7-(4′-(trans-3″-(3‴-pyridylacrylamidobutyl-1,7-dicarbadodecaborane (hm-MC4-PPEA, was a potent inhibitor of nicotinamide phosphoribosyltransferase (Nampt. Nampt has been shown to be upregulated in most cancers and is a promising target for the treatment of many different types of cancers, including breast cancers. Patients and methods: To increase the selectivity of hm-MC4-PPEA toward cancer cells, three prodrugs were synthesized with different hydrolyzable linkers: ester, carbonate, and carbamate. Using click chemistry a fluorophore was attached to these prodrugs to act as a model for our conjugation strategy and to serve as an aid for prodrug stability studies. The stabilities of these drug conjugates were tested in phosphate-buffered saline (PBS at normothermia (37°C using three different pH levels, 5.5, 7.5, and 9.5, as well as in horse serum at physiological pH. The stability of each was monitored using reversed-phase HPLC equipped with both diode array and fluorescence detection. The inhibitory activity of hm-MC4-PPEA was also measured using a commercially available colorimetric assay. The biological activities of the drug conjugates as well as those of the free drug (hm-MC4-PPEA, were evaluated using the MTT assay against the human breast cancer cell lines T47D and MCF7, as well as the noncancerous, transformed, Nampt-dependent human breast epithelium cell line 184A1.Results: hm-MC4-PPEA showed to be a potent inhibitor of recombinant Nampt activity, exhibiting an IC50 concentration of 6.8 nM. The prodrugs showed great stability towards hydrolytic degradation under neutral, mildly acidic and mildly basic conditions. The carbamate prodrug also showed to be stable in rat serum. However, the carbonate and the ester prodrug

  17. A paclitaxel prodrug with bifunctional folate and albumin binding moieties for both passive and active targeted cancer therapy.

    Science.gov (United States)

    Shan, Lingling; Zhuo, Xin; Zhang, Fuwu; Dai, Yunlu; Zhu, Guizhi; Yung, Bryant C; Fan, Wenpei; Zhai, Kefeng; Jacobson, Orit; Kiesewetter, Dale O; Ma, Ying; Gao, Guizhen; Chen, Xiaoyuan

    2018-01-01

    Folate receptor (FR) has proven to be a valuable target for chemotherapy using folic acid (FA) conjugates. However, FA-conjugated chemotherapeutics still have low therapeutic efficacy accompanied with side effects, resulting from complications such as short circulation half-life, limited tumor delivery, as well as high kidney accumulation. Herein, we present a novel FA-conjugated paclitaxel (PTX) prodrug which was additionally conjugated with an Evans blue (EB) derivative for albumin binding. The resulting bifunctional prodrug prolonged blood circulation, enhanced tumor accumulation, and consequently improved tumor therapeutic efficacy. Methods: Fmoc-Cys(Trt)-OH was coupled onto PTX at the 7'-OH position for further synthesis of ester prodrug FA-PTX-EB. The targeting ability was investigated using confocal microscopy and flow cytometry. The pharmacokinetics of this bifunctional compound was also studied. Meanwhile, cell viability was evaluated in normal cells and three cancer cell lines by MTT assay. In vivo therapeutic effect was tested on FR-α overexpressing MDA-MB-231 tumor model. Results: Compared with free PTX, the FA-PTX, PTX-EB and FA-PTX-EB prodrugs increased circulation half-life in mice from 2.19 to 3.82, 4.41, and 7.51 h, respectively. Pharmacokinetics studies showed that the FA-PTX-EB delivered more PTX to tumors than FA-PTX and free PTX. In vitro and in vivo studies demonstrated that FA-EB-conjugated PTX induced potent antitumor activity. Conclusion: FA-PTX-EB showed prolonged blood circulation, enhanced drug accumulation in tumors, higher therapeutic index, and lower side effects than either free PTX or monofunctional FA-PTX and EB-PTX. The results support the potential of using EB for the development of long-acting therapeutics.

  18. Increased diacylglycerol kinase ζ expression in human metastatic colon cancer cells augments Rho GTPase activity and contributes to enhanced invasion

    International Nuclear Information System (INIS)

    Cai, Kun; Mulatz, Kirk; Ard, Ryan; Nguyen, Thanh; Gee, Stephen H

    2014-01-01

    Unraveling the signaling pathways responsible for the establishment of a metastatic phenotype in carcinoma cells is critically important for understanding the pathology of cancer. The acquisition of cell motility is a key property of metastatic tumor cells and is a prerequisite for invasion. Rho GTPases regulate actin cytoskeleton reorganization and the cellular responses required for cell motility and invasion. Diacylglycerol kinase ζ (DGKζ), an enzyme that phosphorylates diacylglycerol to yield phosphatidic acid, regulates the activity of the Rho GTPases Rac1 and RhoA. DGKζ mRNA is highly expressed in several different colon cancer cell lines, as well as in colon cancer tissue relative to normal colonic epithelium, and thus may contribute to the metastatic process. To investigate potential roles of DGKζ in cancer metastasis, a cellular, isogenic model of human colorectal cancer metastatic transition was used. DGKζ protein levels, Rac1 and RhoA activity, and PAK phosphorylation were measured in the non-metastatic SW480 adenocarcinoma cell line and its highly metastatic variant, the SW620 line. The effect of DGKζ silencing on Rho GTPase activity and invasion through Matrigel-coated Transwell inserts was studied in SW620 cells. Invasiveness was also measured in PC-3 prostate cancer and MDA-MB-231 breast cancer cells depleted of DGKζ. DGKζ protein levels were elevated approximately 3-fold in SW620 cells compared to SW480 cells. There was a concomitant increase in active Rac1 in SW620 cells, as well as substantial increases in the expression and phosphorylation of the Rac1 effector PAK1. Similarly, RhoA activity and expression were increased in SW620 cells. Knockdown of DGKζ expression in SW620 cells by shRNA-mediated silencing significantly reduced Rac1 and RhoA activity and attenuated the invasiveness of SW620 cells in vitro. DGKζ silencing in highly metastatic MDA-MB-231 breast cancer cells and PC-3 prostate cancer cells also significantly attenuated

  19. PRODRUGS OF NON- STEROID ANTI - INFLAMMATORY AGENTS (NSAIDS)

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to novel depot formulations (prodrugs) comprising an immobility promoting unit linked via an ester to an active pharmaceutical ingredient, i.a. common NSAIDs. The novel depot formulations are suitable for intra-articular injections and are soluble at slightly acidic p...

  20. Amino Acid Ester Prodrugs of Nucleoside and Nucleotide Antivirals

    Czech Academy of Sciences Publication Activity Database

    Krečmerová, Marcela

    2017-01-01

    Roč. 17, č. 10 (2017), s. 818-833 ISSN 1389-5575 Grant - others:AV ČR(CZ) M200551201 Institutional support: RVO:61388963 Keywords : acyclic nucleoside analogues * antiherpetics * antiretrovirals * cidofovir * peptidomimetics * prodrugs Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 2.661, year: 2016

  1. Antiviral acyclic nucleoside phosphonates: New structures and prodrugs

    Czech Academy of Sciences Publication Activity Database

    Krečmerová, Marcela; Tichý, Tomáš; Pomeisl, Karel; Andrei, G.; Balzarini, J.; Snoeck, R.

    2016-01-01

    Roč. 1, č. 2 (2016), s. 37 [PharmaMed-2016. International Conference on Medicinal and Pharmaceutical Chemistry . 05.12.2016-07.12.2016, Dubai] R&D Projects: GA ČR(CZ) GA14-00522S Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * prodrugs * antivirals * 5-azacytosine Subject RIV: CC - Organic Chemistry

  2. Novel Polymeric Prodrugs of Valproic Acid as Anti- Epilepsy Drugs ...

    African Journals Online (AJOL)

    The release of VPA from polymeric prodrugs was studied using cellophane membrane dialysis bags containing aqueous buffer solutions (pH 1, 7 and 10) at 37 oC. The quantity of released drug was detected by ultraviolet (UV) spectroscopy. Results: 1H-NMR and elemental analyses data for calculating mole composition of ...

  3. Degradation kinetics of metronidazole and its mutual prodrug with ...

    African Journals Online (AJOL)

    Dr Renu Chadha

    degradation of the drug and prodrug as a function of concentration, pH and temperature. In terms of enthalpy of ... Keywords: Calorimetry, stability studies, degradation kinetics, ciprofloxacin, metronidazole. ... action of ciprofloxacin to form a broad spectrum ...... Stability testing of pharmaceutical by isothermal heat conduction.

  4. Hypoxia-Activated Prodrug TH-302 Targets Hypoxic Bone Marrow Niches in Preclinical Leukemia Models.

    Science.gov (United States)

    Benito, Juliana; Ramirez, Marc S; Millward, Niki Zacharias; Velez, Juliana; Harutyunyan, Karine G; Lu, Hongbo; Shi, Yue-Xi; Matre, Polina; Jacamo, Rodrigo; Ma, Helen; Konoplev, Sergej; McQueen, Teresa; Volgin, Andrei; Protopopova, Marina; Mu, Hong; Lee, Jaehyuk; Bhattacharya, Pratip K; Marszalek, Joseph R; Davis, R Eric; Bankson, James A; Cortes, Jorge E; Hart, Charles P; Andreeff, Michael; Konopleva, Marina

    2016-04-01

    To characterize the prevalence of hypoxia in the leukemic bone marrow, its association with metabolic and transcriptional changes in the leukemic blasts and the utility of hypoxia-activated prodrug TH-302 in leukemia models. Hyperpolarized magnetic resonance spectroscopy was utilized to interrogate the pyruvate metabolism of the bone marrow in the murine acute myeloid leukemia (AML) model. Nanostring technology was used to evaluate a gene set defining a hypoxia signature in leukemic blasts and normal donors. The efficacy of the hypoxia-activated prodrug TH-302 was examined in the in vitro and in vivo leukemia models. Metabolic imaging has demonstrated increased glycolysis in the femur of leukemic mice compared with healthy control mice, suggesting metabolic reprogramming of hypoxic bone marrow niches. Primary leukemic blasts in samples from AML patients overexpressed genes defining a "hypoxia index" compared with samples from normal donors. TH-302 depleted hypoxic cells, prolonged survival of xenograft leukemia models, and reduced the leukemia stem cell pool in vivo In the aggressive FLT3/ITD MOLM-13 model, combination of TH-302 with tyrosine kinase inhibitor sorafenib had greater antileukemia effects than either drug alone. Importantly, residual leukemic bone marrow cells in a syngeneic AML model remain hypoxic after chemotherapy. In turn, administration of TH-302 following chemotherapy treatment to mice with residual disease prolonged survival, suggesting that this approach may be suitable for eliminating chemotherapy-resistant leukemia cells. These findings implicate a pathogenic role of hypoxia in leukemia maintenance and chemoresistance and demonstrate the feasibility of targeting hypoxic cells by hypoxia cytotoxins. ©2015 American Association for Cancer Research.

  5. Hypoxia-Inducible Regulation of a Prodrug-Activating Enzyme for Tumor-Specific Gene Therapy

    Directory of Open Access Journals (Sweden)

    Toru Shibata

    2002-01-01

    Full Text Available Previous studies have suggested that tumor hypoxia could be exploited for cancer gene therapy. Using hypoxia-responsive elements derived from the human vascular endothelial growth factor gene, we have generated vectors expressing a bacterial nitroreductase. (20NTR gene that can activate the anticancer prodrug CB1954. Stable transfectants of human HT1080 tumor cells with hypoxia-inducible vectors were established with G418 selection. Hypoxic induction of NTR protein correlated with increased sensitivity to in vitro exposure of HT 1080 cells to the prodrug. Growth delay assays were performed with established tumor xenografts derived from the same cells to detect the in vivo efficacy of CB1954 conversion to its cytotoxic form. Significant antitumor effects were achieved with intraperitoneal injections of CB1954 both in tumors that express NTR constitutively or with a hypoxia-inducible promoter. In addition, respiration of 10% O2 increased tumor hypoxia in vivo and enhanced the antitumor effects. Taken together, these results demonstrate that hypoxia-inducible vectors may be useful for tumor-selective gene therapy, although the problem of delivery of the vector to the tumors, particularly to the hypoxic cells in the tumors, is not addressed by these studies.

  6. Metformin and Its Sulfenamide Prodrugs Inhibit Human Cholinesterase Activity

    Directory of Open Access Journals (Sweden)

    Magdalena Markowicz-Piasecka

    2017-01-01

    Full Text Available The results of epidemiological and pathophysiological studies suggest that type 2 diabetes mellitus (T2DM may predispose to Alzheimer’s disease (AD. The two conditions present similar glucose levels, insulin resistance, and biochemical etiologies such as inflammation and oxidative stress. The diabetic state also contributes to increased acetylcholinesterase (AChE activity, which is one of the factors leading to neurodegeneration in AD. The aim of this study was to assess in vitro the effects of metformin, phenformin, and metformin sulfenamide prodrugs on the activity of human AChE and butyrylcholinesterase (BuChE and establish the type of inhibition. Metformin inhibited 50% of the AChE activity at micromolar concentrations (2.35 μmol/mL, mixed type of inhibition and seemed to be selective towards AChE since it presented low anti-BuChE activity. The tested metformin prodrugs inhibited cholinesterases (ChE at nanomolar range and thus were more active than metformin or phenformin. The cyclohexyl sulfenamide prodrug demonstrated the highest activity towards both AChE (IC50 = 890 nmol/mL, noncompetitive inhibition and BuChE (IC50 = 28 nmol/mL, mixed type inhibition, while the octyl sulfenamide prodrug did not present anti-AChE activity, but exhibited mixed inhibition towards BuChE (IC50 = 184 nmol/mL. Therefore, these two bulkier prodrugs were concluded to be the most selective compounds for BuChE over AChE. In conclusion, it was demonstrated that biguanides present a novel class of inhibitors for AChE and BuChE and encourages further studies of these compounds for developing both selective and nonselective inhibitors of ChEs in the future.

  7. Amphipathic dextran-doxorubicin prodrug micelles for solid tumor therapy.

    Science.gov (United States)

    Jin, Rong; Guo, Xuelian; Dong, Lingli; Xie, Enyuan; Cao, Aoneng

    2017-10-01

    A group of micelles self-assembled from deoxycholic acid-doxorubicin-conjugated dextran (denoted as Dex-DCA-DOX) prodrugs were designed and prepared for pH-triggered drug release and cancer chemotherapy. These prodrugs could be successfully produced by chemically coupling hydrophobic deoxycholic acid (DCA) to dextran hydrazine (denoted as Dex-NHNH 2 ) and hydrazone linker formation between doxorubicin (DOX) and Dex-NHNH 2 . These Dex-DCA-DOX prodrugs self-assembled to form micelles under physiological conditions with varied particle sizes depending on molecular weight of dextran, degree of substitution (DS) of DCA and DOX. After optimization, Dex10k-DCA9-DOX5.5 conjugate comprising dextran of 10kDa, DCA of DS 9 and DOX loading content of 5.5wt%, formed the micelles with the smallest size (110nm). These prodrug micelles could slowly liberate DOX under physiological conditions but efficiently released the drug at an acidified endosomal pH by the hydrolysis of acid-labile hydrazone linker. In vitro cytotoxicity experiment indicated that Dex10k-DCA9-DOX5.5 micelles exerted marked antitumor activity against MCF-7 and SKOV-3 cancer cells. Besides, intravenous administration of the micelles afforded growth inhibition of SKOV-3 tumor bearing in nude mice at a dosage of 2.5mg per kg with anti-cancer efficacy comparable to free DOX-chemotherapy but low systemic toxicity. This study highlights the feasibility of bio-safe and efficient dextran-based prodrug micelles designed for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Activation of multiple chemotherapeutic prodrugs by the natural enzymolome of tumour-localised probiotic bacteria.

    Science.gov (United States)

    Lehouritis, Panos; Stanton, Michael; McCarthy, Florence O; Jeavons, Matthieu; Tangney, Mark

    2016-01-28

    Some chemotherapeutic drugs (prodrugs) require activation by an enzyme for efficacy. We and others have demonstrated the ability of probiotic bacteria to grow specifically within solid tumours following systemic administration, and we hypothesised that the natural enzymatic activity of these tumour-localised bacteria may be suitable for activation of certain such chemotherapeutic drugs. Several wild-type probiotic bacteria; Escherichia coli Nissle, Bifidobacterium breve, Lactococcus lactis and Lactobacillus species, were screened against a panel of popular prodrugs. All strains were capable of activating at least one prodrug. E. coli Nissle 1917 was selected for further studies because of its ability to activate numerous prodrugs and its resistance to prodrug toxicity. HPLC data confirmed biochemical transformation of prodrugs to their toxic counterparts. Further analysis demonstrated that different enzymes can complement prodrug activation, while simultaneous activation of multiple prodrugs (CB1954, 5-FC, AQ4N and Fludarabine phosphate) by E. coli was confirmed, resulting in significant efficacy improvement. Experiments in mice harbouring murine tumours validated in vitro findings, with significant reduction in tumour growth and increase in survival of mice treated with probiotic bacteria and a combination of prodrugs. These findings demonstrate the ability of probiotic bacteria, without the requirement for genetic modification, to enable high-level activation of multiple prodrugs specifically at the site of action. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance

    Science.gov (United States)

    Lu, Kai; Liang, Shan; Wu, Zhen; Bi, Chao; Yu, Yong-Tao; Wang, Xiao-Fang; Zhang, Da-Peng

    2016-01-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana. Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 K372E with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. PMID:27406784

  10. The pkI gene encoding pyruvate kinase I links to the luxZ gene which enhances bioluminescence of the lux operon from Photobacterium leiognathi.

    Science.gov (United States)

    Lin, J W; Lu, H C; Chen, H Y; Weng, S F

    1997-10-09

    Partial 3'-end nucleotide sequence of the pkI gene (GenBank accession No. AF019143) from Photobacterium leiognathi ATCC 25521 has been determined, and the encoded pyruvate kinase I is deduced. Pyruvate kinase I is the key enzyme of glycolysis, which converts phosphoenol pyruvate to pyruvate. Alignment and comparison of pyruvate kinase Is from P. leiognathi, E. coli and Salmonella typhimurium show that they are homologous. Nucleotide sequence reveals that the pkI gene is linked to the luxZ gene that enhances bioluminescence of the lux operon from P. leiognathi. The gene order of the pkI and luxZ genes is-pk1-ter-->-R&R"-luxZ-ter"-->, whereas ter is transcriptional terminator for the pkI and related genes, and R&R" is the regulatory region and ter" is transcriptional terminator for the luxZ gene. It clearly elicits that the pkI gene and luxZ gene are divided to two operons. Functional analysis confirms that the potential hairpin loop omega T is the transcriptional terminator for the pkI and related genes. It infers that the pkI and related genes are simply linked to the luxZ gene in P. leiognathi genome.

  11. Expression of the Grb2-related protein of the lymphoid system in B cell subsets enhances B cell antigen receptor signaling through mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yankee, Thomas M; Solow, Sasha A; Draves, Kevin D; Clark, Edward A

    2003-01-01

    Adapter proteins play a critical role in regulating signals triggered by Ag receptor cross-linking. These small molecules link receptor proximal events with downstream signaling pathways. In this study, we explore the expression and function of the Grb2-related protein of the lymphoid system (GrpL)/Grb2-related adaptor downstream of Shc adapter protein in human B cells. GrpL is expressed in naive B cells and is down-regulated following B cell Ag receptor ligation. By contrast, germinal center and memory B cells express little or no GrpL. Using human B cell lines, we detected constitutive interactions between GrpL and B cell linker protein, Src homology (SH)2 domain-containing leukocyte protein of 76 kDa, hemopoietic progenitor kinase 1, and c-Cbl. The N-terminal SH3 domain of GrpL binds c-Cbl while the C-terminal SH3 domain binds B cell linker protein and SH2 domain-containing leukocyte protein of 76 kDa. Exogenous expression of GrpL in a GrpL-negative B cell line leads to enhanced Ag receptor-induced extracellular signal-related kinase and p38 mitogen-activated protein kinase phosphorylation. Thus, GrpL expression in human B cell subsets appears to regulate Ag receptor-mediated signaling events.

  12. Tamm-Horsfall Glycoprotein Enhances PMN Phagocytosis by Binding to Cell Surface-Expressed Lactoferrin and Cathepsin G That Activates MAP Kinase Pathway

    Directory of Open Access Journals (Sweden)

    Chia-Li Yu

    2011-03-01

    Full Text Available The molecular basis of polymorphonuclear neutrophil (PMN phagocytosis-enhancing activity (PEA by human purified urinary Tamm-Horsfall glyco- protein (THP has not been elucidated. In this study, we found human THP bound to lactoferrin (LF and cathepsin G (CG expressed on the surface of PMN, identified by a proteomic study with MALDI-TOF- LC/LC/mass spectrometric analysis. Pre-incubation of 10% SDS-PAGE electrophoresed PMN lysates with monoclonal anti-LF or anti-CG antibody reduced the binding with THP. To elucidate the signaling pathway of THP on PMN activation, we found THP enhanced ERK1/2 phosphorylation, reduced p38 MAP kinase phosphorylation, but had no effect on DNA binding of the five NF-kB family members in PMN. To further clarify whether the carbohydrate-side chains or protein-core structure in THP molecule is responsible for THP-PEA, THP was cleaved by different degrading enzymes with carbohydrate specificity (neuraminidase and β-galactosidase, protein specificity (V8 protease and proteinase K or glycoconjugate specificity (carboxylpeptidase Y and O-sialoglycoprotein endopeptidase. We clearly demonstrated that the intact protein-core structure in THP molecule was more important for THP-PEA than carbohydrate-side chains. Putting these results together, we conclude that THP adheres to surface-expressed LF and CG on PMN and transduces signaling via the MAP kinase pathway to enhance PMN phagocytosis.

  13. pH- and NIR Light-Responsive Polymeric Prodrug Micelles for Hyperthermia-Assisted Site-Specific Chemotherapy to Reverse Drug Resistance in Cancer Treatment.

    Science.gov (United States)

    Li, Zuhong; Wang, Haibo; Chen, Yangjun; Wang, Yin; Li, Huan; Han, Haijie; Chen, Tingting; Jin, Qiao; Ji, Jian

    2016-05-01

    Despite the exciting advances in cancer chemotherapy over past decades, drug resistance in cancer treatment remains one of the primary reasons for therapeutic failure. IR-780 loaded pH-responsive polymeric prodrug micelles with near infrared (NIR) photothermal effect are developed to circumvent the drug resistance in cancer treatment. The polymeric prodrug micelles are stable in physiological environment, while exhibit fast doxorubicin (DOX) release in acidic condition and significant temperature elevation under NIR laser irradiation. Phosphorylcholine-based biomimetic micellar shell and acid-sensitive drug conjugation endow them with prolonged circulation time and reduced premature drug release during circulation to conduct tumor site-specific chemotherapy. The polymeric prodrug micelles combined with NIR laser irradiation could significantly enhance intracellular DOX accumulation and synergistically induce the cell apoptosis in DOX-resistant MCF-7/ADR cells. Meanwhile, the tumor site-specific chemotherapy combined with hyperthermia effect induces significant inhibition of MCF-7/ADR tumor growth in tumor-bearing mice. These results demonstrate that the well-designed IR-780 loaded polymeric prodrug micelles for hyperthermia-assisted site-specific chemotherapy present an effective approach to reverse drug resistance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Utilization of prodrugs to enhance the transdermal absorption of morphine

    DEFF Research Database (Denmark)

    Drustrup, J.; Fullerton, A.; Christrup, Lona Louring

    1991-01-01

    . The esters showed generally a higher water and lipid solubility than morphine and were also much more lipophilic than the parent drug in terms of octanol-buffer partition coefficients. Diffusion experiments in vitro using human skin samples showed that whereas morphine did not penetrate the skin to any...

  15. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    DEFF Research Database (Denmark)

    Christiansen, Louise Slot; Egeblad, Louise; Munch-Petersen, Birgitte

    2015-01-01

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been t...

  16. GPS 2.1: enhanced prediction of kinase-specific phosphorylation sites with an algorithm of motif length selection.

    Science.gov (United States)

    Xue, Yu; Liu, Zexian; Cao, Jun; Ma, Qian; Gao, Xinjiao; Wang, Qingqi; Jin, Changjiang; Zhou, Yanhong; Wen, Longping; Ren, Jian

    2011-03-01

    As the most important post-translational modification of proteins, phosphorylation plays essential roles in all aspects of biological processes. Besides experimental approaches, computational prediction of phosphorylated proteins with their kinase-specific phosphorylation sites has also emerged as a popular strategy, for its low-cost, fast-speed and convenience. In this work, we developed a kinase-specific phosphorylation sites predictor of GPS 2.1 (Group-based Prediction System), with a novel but simple approach of motif length selection (MLS). By this approach, the robustness of the prediction system was greatly improved. All algorithms in GPS old versions were also reserved and integrated in GPS 2.1. The online service and local packages of GPS 2.1 were implemented in JAVA 1.5 (J2SE 5.0) and freely available for academic researches at: http://gps.biocuckoo.org.

  17. Long-Acting Diclofenac Ester Prodrugs for Joint Injection: Kinetics, Mechanism of Degradation, and In Vitro Release From Prodrug Suspension.

    Science.gov (United States)

    Mertz, Nina; Larsen, Susan Weng; Kristensen, Jesper; Østergaard, Jesper; Larsen, Claus

    2016-10-01

    A prodrug approach for local and sustained diclofenac action after injection into joints based on ester prodrugs having a pH-dependent solubility is presented. Inherent ester prodrug properties influencing the duration of action include their pH-dependent solubility and charge state, as well as susceptibility to undergo esterase facilitated hydrolysis. In this study, physicochemical properties and pH rate profiles of 3 diclofenac ester prodrugs differing with respect to the spacer carbon chain length between the drug and the imidazole-based promoiety were determined and a rate equation for prodrug degradation in aqueous solution in the pH range 1-10 was derived. In the pH range 6-10, the prodrugs were subject to parallel degradation to yield diclofenac and an indolinone derivative. The prodrug degradation was found to be about 6-fold faster in 80% (vol/vol) human plasma as compared to 80% (vol/vol) human synovial fluid with 2-(1-methyl-1H-imidazol-2-yl)ethyl 2-(2-(2,6 dichlorophenyl)amino)phenylacetate being the poorest substrate toward enzymatic cleavage. The conversion and release of parent diclofenac from prodrug suspensions in vitro were studied using the rotating dialysis model. The results suggest that it is possible to alter and control dissolution and reconversion behavior of the diclofenac prodrugs, thus making the prodrug approach feasible for local and sustained diclofenac action after joint injection. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  18. Genistein, a tyrosine kinase inhibitor, enhanced radiosensitivity in human esophageal cancer cell lines in vitro: Possible involvement of inhibition of survival signal transduction pathways

    International Nuclear Information System (INIS)

    Akimoto, Tetsuo; Nonaka, Tetsuo; Ishikawa, Hitoshi; Sakurai, Hideyuki; Saitoh, Jun-ichi; Takahashi, Takeo; Mitsuhashi, Norio

    2001-01-01

    Purpose: The effect of genistein, a tyrosine kinase inhibitor, on radiosensitivity was examined, especially focusing on 'survival signal transduction pathways'. Methods and Materials: Two human esophageal squamous cell cancer cell lines, TE-1 (p53, mutant) and TE-2 (p53, wild), were used. Radiosensitivity was determined by clonogenic assay, and activation of survival signals was examined by Western blot. Results: Genistein (30 μM) greatly enhanced radiosensitivity in these cell lines by suppressing radiation-induced activation of survival signals, p42/p44 extracellular signal-regulated kinase and AKT/PKB. Significant increase in the percentage of apoptotic cells and increased poly[ADP-ribose] polymerase cleavage were observed in TE-2, but not in TE-1 even after combination of genistein with irradiation. In terms of changes in expression of p53-related proteins, increase in expression of Bax and decrease in that of Bcl-2 were observed in TE-2 but not in TE-1, suggesting that the main mode of cell death induced by genistein in a cell line with wild type p53 differed from that with mutant p53. Conclusions: This study suggested that survival signals, including p42/p44 ERK and AKT/PKB, may be involved in determining radiosensitivity, and genistein would be a potent therapeutic agent that has an enhancing effect on radiation

  19. Pharmacological Evaluation and Preliminary Pharmacokinetics Studies of a New Diclofenac Prodrug without Gastric Ulceration Effect

    OpenAIRE

    dos Santos, Jean Leandro [UNESP; Moreira, Vanessa; Campos, Michel Leandro [UNESP; Chelucci, Rafael Consolin [UNESP; Barbieri, Karina Pereira [UNESP; Maggio de Castro Souto, Pollyana Cristina; Matsubara, Marcio Hideki; Teixeira, Catarina; Bosquesi, Priscila Longhin [UNESP; Peccinini, Rosangela Goncalves [UNESP; Chin, Chung Man [UNESP

    2012-01-01

    Long-term nonsteroidal anti-inflammatory drugs (NSAIDs) therapy has been associated with several adverse effects such as gastric ulceration and cardiovascular events. Among the molecular modifications strategies, the prodrug approach is a useful tool to discover new safe NSAIDs. The 1-(2,6-dichlorophenyl)indolin-2-one is a diclofenac prodrug which demonstrated relevant anti-inflammatory properties without gastro ulceration effect. In addition, the prodrug decreases PGE(2) levels, COX-2 expres...

  20. Application of Prodrugs to Inflammatory Diseases of the Gut

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Ebersole

    2008-02-01

    Full Text Available Oral delivery is the most common and preferred route of drug administrationalthough the digestive tract exhibits several obstacles to drug delivery including motilityand intraluminal pH profiles. The gut milieu represents the largest mucosal surfaceexposed to microorganisms with 1010-12 colony forming bacteria/g of colonic content.Approximately, one third of fecal dry matter is made of bacteria/ bacterial components.Indeed, the normal gut microbiota is responsible for healthy digestion of dietary fibers(polysaccharides and fermentation of short chain fatty acids such as acetate and butyratethat provide carbon sources (fuel for these bacteria. Inflammatory bowel disease (IBDresults in breakage of the mucosal barrier, an altered microbiota and dysregulated gutimmunity. Prodrugs that are chemically constructed to target colonic release or aredegraded specifically by colonic bacteria, can be useful in the treatment of IBD. Thisreview describes the progress in digestive tract prodrug design and delivery in light of gutmetabolic activities.

  1. Saliva-catalyzed hydrolysis of a ketobemidone ester prodrug

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    1992-01-01

    Saliva enzyme-catalysed hydrolysis of ester prodrugs or drugs containing sensitive ester groups may be a limiting factor for the buccal absorption of such compounds. Using the isopropyl carbonate ester of ketobemidone as a model substance of a hydrolysis-sensitive prodrug the esterase activity...... of human saliva has been characterized as a function of various factors. The esterase activity was found to decrease rapidly upon storage of the saliva at 37°C. The activity increased with increasing pH in the range 4.5-7.4 and with increasing salivation flow rate up to a rate of 0.9 ml min. Under resting...... conditions, the flow rate was about 0.2 ml min which implied a greatly decreased esterase activity. The activity was highest after fasting and decreased after intake of a meal. The intraindividual variation in the saliva esterase activity was small whereas a larger interindividual variation was found....

  2. Tyrosine kinases in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Kobayashi Akiko

    2011-08-01

    Full Text Available Abstract Rheumatoid arthritis (RA is an inflammatory, polyarticular joint disease. A number of cellular responses are involved in the pathogenesis of rheumatoid arthritis, including activation of inflammatory cells and cytokine expression. The cellular responses involved in each of these processes depends on the specific signaling pathways that are activated; many of which include protein tyrosine kinases. These pathways include the mitogen-activated protein kinase pathway, Janus kinases/signal transducers and activators transcription pathway, spleen tyrosine kinase signaling, and the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Many drugs are in development to target tyrosine kinases for the treatment of RA. Based on the number of recently published studies, this manuscript reviews the role of tyrosine kinases in the pathogenesis of RA and the potential role of kinase inhibitors as new therapeutic strategies of RA.

  3. Puromycin-sensitive aminopeptidase: an antiviral prodrug activating enzyme.

    Science.gov (United States)

    Tehler, Ulrika; Nelson, Cara H; Peterson, Larryn W; Provoda, Chester J; Hilfinger, John M; Lee, Kyung-Dall; McKenna, Charles E; Amidon, Gordon L

    2010-03-01

    Cidofovir (HPMPC) is a broad-spectrum antiviral agent, currently used to treat AIDS-related human cytomegalovirus retinitis. Cidofovir has recognized therapeutic potential for orthopox virus infections, although its use is hampered by its inherent low oral bioavailability. Val-Ser-cyclic HPMPC (Val-Ser-cHPMPC) is a promising peptide prodrug which has previously been shown by us to improve the permeability and bioavailability of the parent compound in rodent models (Eriksson et al., 2008. Molecular Pharmaceutics 5, 598-609). Puromycin-sensitive aminopeptidase was partially purified from Caco-2 cell homogenates and identified as a prodrug activating enzyme for Val-Ser-cHPMPC. The prodrug activation process initially involves an enzymatic step where the l-Valine residue is removed by puromycin-sensitive aminopeptidase, a step that is bestatin-sensitive. Subsequent chemical hydrolysis results in the generation of cHPMPC. A recombinant puromycin-sensitive aminopeptidase was generated and its substrate specificity investigated. The k(cat) for Val-pNA was significantly lower than that for Ala-pNA, suggesting that some amino acids are preferred over others. Furthermore, the three-fold higher k(cat) for Val-Ser-cHPMPC as compared to Val-pNA suggests that the leaving group may play an important role in determining hydrolytic activity. In addition to its ability to hydrolyze a variety of substrates, these observations strongly suggest that puromycin-sensitive aminopeptidase is an important enzyme for activating Val-Ser-cHPMPC in vivo. Taken together, our data suggest that puromycin-sensitive aminopeptidase makes an attractive target for future prodrug design.

  4. Chronic Hypoxia Enhances Expression and Activity of Mitochondrial Creatine Kinase and Hexokinase in the Rat Ventricular Myocardium

    Czech Academy of Sciences Publication Activity Database

    Wasková-Arnoštová, P.; Kašparová, D.; Elsnicová, B.; Novotný, J.; Neckář, Jan; Kolář, František; Žurmanová, J.

    2014-01-01

    Roč. 33, č. 2 (2014), s. 310-320 ISSN 1015-8987 R&D Projects: GA AV ČR(CZ) IAAX01110901; GA ČR(CZ) GAP303/12/1162 Grant - others:Univerzita Karlova(CZ) 349211; GA AV ČR(CZ) IAA601110908 Institutional support: RVO:67985823 Keywords : creatine kinase * hexokinase * normobaric hypoxia * left ventricle * right ventricle * mitochondria co-localization Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 2.875, year: 2014

  5. Cholesterylbutyrate Solid Lipid Nanoparticles as a Butyric Acid Prodrug

    Directory of Open Access Journals (Sweden)

    Alessandro Mauro

    2008-02-01

    Full Text Available Cholesterylbutyrate (Chol-but was chosen as a prodrug of butyric acid.Butyrate is not often used in vivo because its half-life is very short and therefore too largeamounts of the drug would be necessary for its efficacy. In the last few years butyric acid'santi-inflammatory properties and its inhibitory activity towards histone deacetylases havebeen widely studied, mainly in vitro. Solid Lipid Nanoparticles (SLNs, whose lipid matrixis Chol-but, were prepared to evaluate the delivery system of Chol-but as a prodrug and totest its efficacy in vitro and in vivo. Chol-but SLNs were prepared using the microemulsionmethod; their average diameter is on the order of 100-150 nm and their shape is spherical.The antineoplastic effects of Chol-but SLNs were assessed in vitro on different cancer celllines and in vivo on a rat intracerebral glioma model. The anti-inflammatory activity wasevaluated on adhesion of polymorphonuclear cells to vascular endothelial cells. In thereview we will present data on Chol-but SLNs in vitro and in vivo experiments, discussingthe possible utilisation of nanoparticles for the delivery of prodrugs for neoplastic andchronic inflammatory diseases.

  6. Synthesis and evaluation of water-soluble poly(vinyl alcohol)-paclitaxel conjugate as a macromolecular prodrug

    International Nuclear Information System (INIS)

    Kakinoki, Atsufumi; Kaneo, Yoshiharu; Tanaka, Tetsuro; Hosokawa, Yoshitsugu

    2008-01-01

    Paclitaxel (PTX) is an antitumor agent for the treatment of various human cancers. Cremophor EL and ethanol are used to formulate PTX in commercial injection solutions, because of its poor solubility in water. However, these agents cause severe allergic reaction upon intravenous administration. The aim of this study is to synthesize water-soluble macromolecular prodrugs of PTX for enhancing the therapeutic efficacy. Poly (vinyl alcohol) (PVA, 80 kDa), water-soluble synthetic polymer, was used as a drug carrier which is safe and stable in the body. The 2'-hydroxyl group of PTX was reacted with succinic anhydride and then carboxylic group of the succinyl spacer was coupled to PVA via ethylene diamine spacer, resulting the water-soluble prodrug of poly (vinyl alcohol)-paclitaxel conjugate (PVA-SPTX). The solubility of PTX was greatly enhanced by the conjugation to PVA. The release of PTX from the conjugate was accelerated at the neutral to basic conditions in in vitro release experiment. [ 125 I]-labeled PVA-SPTX was retained in the blood circulation for several days and was gradually distributed into the tumorous tissue after intravenous injection to the tumor-bearing mice. PVA-SPTX inhibited the growth of sarcoma 180 cells subcutaneously inoculated in mice. It was suggested that the water-solubility of PTX was markedly enhanced by the conjugation to PVA, and PVA-SPTX effectively delivered PTX to the tumorous tissue due to the enhanced permeability and retention (EPR) effect. (author)

  7. Toxicology and Biodistribution Studies for MGH2.1, an Oncolytic Virus that Expresses Two Prodrug-activating Genes, in Combination with Prodrugs

    Directory of Open Access Journals (Sweden)

    Kazue Kasai

    2013-01-01

    Full Text Available MGH2.1 is a herpes simplex virus type 1 (HSV1 oncolytic virus that expresses two prodrug-activating transgenes: the cyclophosphamide (CPA-activating cytochrome P4502B1 (CYP2B1 and the CPT11-activating secreted human intestinal carboxylesterase (shiCE. Toxicology and biodistribution of MGH2.1 in the presence/absence of prodrugs was evaluated in mice. MGH2.1 ± prodrugs was cytotoxic to human glioma cells, but not to normal cells. Pharmacokinetically, intracranial MGH2.1 did not significantly alter the metabolism of intraperitoneally (i.p. administered prodrugs in mouse plasma, brain, or liver. MGH2.1 did not induce an acute inflammatory reaction. MGH2.1 DNA was detected in brains of mice inoculated with 108 pfus for up to 60 days. However, only one animal showed evidence of viral gene expression at this time. Expression of virally encoded genes was restricted to brain. Intracranial inoculation of MGH2.1 did not induce lethality at 108 pfus in the absence of prodrugs and at 106 pfus in the presence of prodrugs. This study provides safety and toxicology data justifying a possible clinical trial of intratumoral injection of MGH2.1 with peripheral administration of CPA and/or CPT11 prodrugs in humans with malignant gliomas.

  8. Inhibition of glycogen synthase kinase-3 enhances the differentiation and reduces the proliferation of adult human olfactory epithelium neural precursors

    Energy Technology Data Exchange (ETDEWEB)

    Manceur, Aziza P. [Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, Toronto, Ontario (Canada); Donnelly Centre, University of Toronto, Toronto, Ontario (Canada); Tseng, Michael [Laboratory of Cellular and Molecular Pathophysiology, Centre for Addiction and Mental Health (CAMH), University of Toronto, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada); Holowacz, Tamara [Donnelly Centre, University of Toronto, Toronto, Ontario (Canada); Witterick, Ian [Institute of Medical Science, University of Toronto, Toronto, ON (Canada); Department of Otolaryngology, Head and Neck Surgery, University of Toronto, ON (Canada); Weksberg, Rosanna [Institute of Medical Science, University of Toronto, Toronto, ON (Canada); The Hospital for Sick Children, Research Institute, Program in Genetics and Genomic Biology, Toronto, Ontario Canada (Canada); McCurdy, Richard D. [The Hospital for Sick Children, Research Institute, Program in Genetics and Genomic Biology, Toronto, Ontario Canada (Canada); Warsh, Jerry J. [Laboratory of Cellular and Molecular Pathophysiology, Centre for Addiction and Mental Health (CAMH), University of Toronto, Toronto, Ontario (Canada); Department of Psychiatry, University of Toronto, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada); Audet, Julie, E-mail: julie.audet@utoronto.ca [Institute of Biomaterials and Biomedical Engineering (IBBME), University of Toronto, Toronto, Ontario (Canada); Donnelly Centre, University of Toronto, Toronto, Ontario (Canada)

    2011-09-10

    The olfactory epithelium (OE) contains neural precursor cells which can be easily harvested from a minimally invasive nasal biopsy, making them a valuable cell source to study human neural cell lineages in health and disease. Glycogen synthase kinase-3 (GSK-3) has been implicated in the etiology and treatment of neuropsychiatric disorders and also in the regulation of murine neural precursor cell fate in vitro and in vivo. In this study, we examined the impact of decreased GSK-3 activity on the fate of adult human OE neural precursors in vitro. GSK-3 inhibition was achieved using ATP-competitive (6-bromoindirubin-3'-oxime and CHIR99021) or substrate-competitive (TAT-eIF2B) inhibitors to eliminate potential confounding effects on cell fate due to off-target kinase inhibition. GSK-3 inhibitors decreased the number of neural precursor cells in OE cell cultures through a reduction in proliferation. Decreased proliferation was not associated with a reduction in cell survival but was accompanied by a reduction in nestin expression and a substantial increase in the expression of the neuronal differentiation markers MAP1B and neurofilament (NF-M) after 10 days in culture. Taken together, these results suggest that GSK-3 inhibition promotes the early stages of neuronal differentiation in cultures of adult human neural precursors and provide insights into the mechanisms by which alterations in GSK-3 signaling affect adult human neurogenesis, a cellular process strongly suspected to play a role in the etiology of neuropsychiatric disorders.

  9. Inhibition of glycogen synthase kinase-3 enhances the differentiation and reduces the proliferation of adult human olfactory epithelium neural precursors

    International Nuclear Information System (INIS)

    Manceur, Aziza P.; Tseng, Michael; Holowacz, Tamara; Witterick, Ian; Weksberg, Rosanna; McCurdy, Richard D.; Warsh, Jerry J.; Audet, Julie

    2011-01-01

    The olfactory epithelium (OE) contains neural precursor cells which can be easily harvested from a minimally invasive nasal biopsy, making them a valuable cell source to study human neural cell lineages in health and disease. Glycogen synthase kinase-3 (GSK-3) has been implicated in the etiology and treatment of neuropsychiatric disorders and also in the regulation of murine neural precursor cell fate in vitro and in vivo. In this study, we examined the impact of decreased GSK-3 activity on the fate of adult human OE neural precursors in vitro. GSK-3 inhibition was achieved using ATP-competitive (6-bromoindirubin-3'-oxime and CHIR99021) or substrate-competitive (TAT-eIF2B) inhibitors to eliminate potential confounding effects on cell fate due to off-target kinase inhibition. GSK-3 inhibitors decreased the number of neural precursor cells in OE cell cultures through a reduction in proliferation. Decreased proliferation was not associated with a reduction in cell survival but was accompanied by a reduction in nestin expression and a substantial increase in the expression of the neuronal differentiation markers MAP1B and neurofilament (NF-M) after 10 days in culture. Taken together, these results suggest that GSK-3 inhibition promotes the early stages of neuronal differentiation in cultures of adult human neural precursors and provide insights into the mechanisms by which alterations in GSK-3 signaling affect adult human neurogenesis, a cellular process strongly suspected to play a role in the etiology of neuropsychiatric disorders.

  10. Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance.

    Science.gov (United States)

    Lu, Kai; Liang, Shan; Wu, Zhen; Bi, Chao; Yu, Yong-Tao; Wang, Xiao-Fang; Zhang, Da-Peng

    2016-09-01

    Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 (K372E) with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  11. Thiazolidinone prodrugs activated by reactive oxygen species for use in the treatment of inflammatory diseases and cancer

    DEFF Research Database (Denmark)

    2018-01-01

    Prodrugs activated predominantly or exclusively in inflammatory tissue, more particularly prodrugs of methotrexate and derivatives thereof, which are selectively activated by Reactive Oxygen Species (ROS) in inflammatory tissues associated with cancer and inflammatory diseases, as well as method...

  12. Chemical and enzymatic stability of amino acid prodrugs containing methoxy, ethoxy and propylene glycol linkers.

    Science.gov (United States)

    Gupta, Deepak; Gupta, Sheeba Varghese; Lee, Kyung-Dall; Amidon, Gordon L

    2009-01-01

    We evaluated the chemical and enzymatic stabilities of prodrugs containing methoxy, ethoxy and propylene glycol linkers in order to find a suitable linker for prodrugs of carboxylic acids with amino acids. l-Valine and l-phenylalanine prodrugs of model compounds (benzoic acid and phenyl acetic acid) containing methoxy, ethoxy and propylene glycol linkers were synthesized. The hydrolysis rate profile of each compound was studied at physiologically relevant pHs (1.2, 4, 6 and 7.4). Enzymatic hydrolysis of propylene glycol containing compounds was studied using Caco-2 homogenate as well as purified enzyme valacyclovirase. It was observed that the stability of the prodrugs increases with the linker length (propyl > ethyl > methyl). The model prodrugs were stable at acidic pH as compared to basic pH. It was observed that the prodrug with the aliphatic amino acid promoiety was more stable compared to its aromatic counterpart. The comparison between benzyl and the phenyl model compounds revealed that the amino acid side chain is significant in determining the stability of the prodrug whereas the benzyl or phenyl carboxylic acid had little or no effect on the stability. The enzymatic activation studies of propylene glycol linker prodrug in the presence of valacyclovirase and cell homogenate showed faster generation of the parent drug at pH 7.4. The half-life of prodrugs at pH 7.4 was more than 12 h, whereas in the presence of cell homogenate the half-lives were less than 1 h. Hydrolysis by Caco-2 homogenate generated the parent compound in two steps, where the prodrug was first converted to the intermediate, propylene glycol benzoate, which was then converted to the parent compound (benzoic acid). Enzymatic hydrolysis of propylene glycol containing prodrugs by valacyclovirase showed hydrolysis of the amino acid ester part to generate the propylene glycol ester of model compound (propylene glycol benzoate) as the major product. The amino acid prodrugs containing methoxy

  13. Synthesis, Bioevaluation and Molecular Dynamic Simulation Studies of Dexibuprofen–Antioxidant Mutual Prodrugs

    Directory of Open Access Journals (Sweden)

    Zaman Ashraf

    2016-12-01

    Full Text Available Dexibuprofen–antioxidant conjugates were synthesized with the aim to reduce its gastrointestinal effects. The esters analogs of dexibuprofen 5a–c were obtained by reacting its –COOH group with chloroacetyl derivatives 3a–c. The in vitro hydrolysis data confirmed that synthesized prodrugs 5a–c were stable in stomach while undergo significant hydrolysis in 80% human plasma and thus release free dexibuprofen. The minimum reversion was observed at pH 1.2 suggesting that prodrugs are less irritating to stomach than dexibuprofen. The anti-inflammatory activity of 5c (p < 0.001 is more significant than the parent dexibuprofen. The prodrug 5c produced maximum inhibition (42.06% of paw-edema against egg-albumin induced inflammation in mice. Anti-pyretic effects in mice indicated that prodrugs 5a and 5b showed significant inhibition of pyrexia (p < 0.001. The analgesic activity of 5a is more pronounced compared to other synthesized prodrugs. The mean percent inhibition indicated that the prodrug 5a was more active in decreasing the number of writhes induced by acetic acid than standard dexibuprofen. The ulcerogenic activity results assured that synthesized prodrugs produce less gastrointestinal adverse effects than dexibuprofen. The ex vivo antiplatelet aggregation activity results also confirmed that synthesized prodrugs are less irritant to gastrointestinal mucosa than the parent dexibuprofen. Molecular docking analysis showed that the prodrugs 5a–c interacts with the residues present in active binding sites of target protein. The stability of drug–target complexes is verified by molecular dynamic simulation study. It exhibited that synthesized prodrugs formed stable complexes with the COX-2 protein thus support our wet lab results. It is therefore concluded that the synthesized prodrugs have promising pharmacological activities with reduced gastrointestinal adverse effects than the parent drug.

  14. Telmisartan enhances mitochondrial activity and alters cellular functions in human coronary artery endothelial cells via AMP-activated protein kinase pathway.

    Science.gov (United States)

    Kurokawa, Hirofumi; Sugiyama, Seigo; Nozaki, Toshimitsu; Sugamura, Koichi; Toyama, Kensuke; Matsubara, Junichi; Fujisue, Koichiro; Ohba, Keisuke; Maeda, Hirofumi; Konishi, Masaaki; Akiyama, Eiichi; Sumida, Hitoshi; Izumiya, Yasuhiro; Yasuda, Osamu; Kim-Mitsuyama, Shokei; Ogawa, Hisao

    2015-04-01

    Mitochondrial dysfunction plays an important role in cellular senescence and impaired function of vascular endothelium, resulted in cardiovascular diseases. Telmisartan is a unique angiotensin II type I receptor blocker that has been shown to prevent cardiovascular events in high risk patients. AMP-activated protein kinase (AMPK) plays a critical role in mitochondrial biogenesis and endothelial function. This study assessed whether telmisartan enhances mitochondrial function and alters cellular functions via AMPK in human coronary artery endothelial cells (HCAECs). In cultured HCAECs, telmisartan significantly enhanced mitochondrial activity assessed by mitochondrial reductase activity and intracellular ATP production and increased the expression of mitochondria related genes. Telmisartan prevented cellular senescence and exhibited the anti-apoptotic and pro-angiogenic properties. The expression of genes related anti-oxidant and pro-angiogenic properties were increased by telmisartan. Telmisartan increased endothelial NO synthase and AMPK phosphorylation. Peroxisome proliferator-activated receptor gamma signaling was not involved in telmisartan-induced improvement of mitochondrial function. All of these effects were abolished by inhibition of AMPK. Telmisartan enhanced mitochondrial activity and exhibited anti-senescence effects and improving endothelial function through AMPK in HCAECs. Telmisartan could provide beneficial effects on vascular diseases via enhancement of mitochondrial activity and modulating endothelial function through AMPK activation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Protein kinase A-dependent Neuronal Nitric Oxide Synthase Activation Mediates the Enhancement of Baroreflex Response by Adrenomedullin in the Nucleus Tractus Solitarii of Rats

    Directory of Open Access Journals (Sweden)

    Ho I-Chun

    2011-05-01

    Full Text Available Abstract Background Adrenomedullin (ADM exerts its biological functions through the receptor-mediated enzymatic mechanisms that involve protein kinase A (PKA, or neuronal nitric oxide synthase (nNOS. We previously demonstrated that the receptor-mediated cAMP/PKA pathway involves in ADM-enhanced baroreceptor reflex (BRR response. It remains unclear whether ADM may enhance BRR response via activation of nNOS-dependent mechanism in the nucleus tractus solitarii (NTS. Methods Intravenous injection of phenylephrine was administered to evoke the BRR before and at 10, 30, and 60 min after microinjection of the test agents into NTS of Sprague-Dawley rats. Western blotting analysis was used to measure the level and phosphorylation of proteins that involved in BRR-enhancing effects of ADM (0.2 pmol in NTS. The colocalization of PKA and nNOS was examined by immunohistochemical staining and observed with a laser confocal microscope. Results We found that ADM-induced enhancement of BRR response was blunted by microinjection of NPLA or Rp-8-Br-cGMP, a selective inhibitor of nNOS or protein kinase G (PKG respectively, into NTS. Western blot analysis further revealed that ADM induced an increase in the protein level of PKG-I which could be attenuated by co-microinjection with the ADM receptor antagonist ADM22-52 or NPLA. Moreover, we observed an increase in phosphorylation at Ser1416 of nNOS at 10, 30, and 60 min after intra-NTS administration of ADM. As such, nNOS/PKG signaling may also account for the enhancing effect of ADM on BRR response. Interestingly, biochemical evidence further showed that ADM-induced increase of nNOS phosphorylation was prevented by co-microinjection with Rp-8-Br-cAMP, a PKA inhibitor. The possibility of PKA-dependent nNOS activation was substantiated by immunohistochemical demonstration of co-localization of PKA and nNOS in putative NTS neurons. Conclusions The novel finding of this study is that the signal transduction cascade that

  16. Overexpression of Protein Kinase Mζ in the Hippocampus Enhances Long-Term Potentiation and Long-Term Contextual But Not Cued Fear Memory in Rats.

    Science.gov (United States)

    Schuette, Sven R M; Fernández-Fernández, Diego; Lamla, Thorsten; Rosenbrock, Holger; Hobson, Scott

    2016-04-13

    The persistently active protein kinase Mζ (PKMζ) has been found to be involved in the formation and maintenance of long-term memory. Most of the studies investigating PKMζ, however, have used either putatively unselective inhibitors or conventional knock-out animal models in which compensatory mechanisms may occur. Here, we overexpressed an active form of PKMζ in rat hippocampus, a structure highly involved in memory formation, and embedded in several neural networks. We investigated PKMζ's influence on synaptic plasticity using electrophysiological recordings of basal transmission, paired pulse facilitation, and LTP and combined this with behavioral cognitive experiments addressing formation and retention of both contextual memory during aversive conditioning and spatial memory during spontaneous exploration. We demonstrate that hippocampal slices overexpressing PKMζ show enhanced basal transmission, suggesting a potential role of PKMζ in postsynaptic AMPAR trafficking. Moreover, the PKMζ-overexpressing slices augmented LTP and this effect was not abolished by protein-synthesis blockers, indicating that PKMζ induces enhanced LTP formation in a protein-synthesis-independent manner. In addition, we found selectively enhanced long-term memory for contextual but not cued fear memory, underlining the theory of the hippocampus' involvement in the contextual aspect of aversive reinforced tasks. Memory for spatial orientation during spontaneous exploration remained unaltered, suggesting that PKMζ may not affect the neural circuits underlying spontaneous tasks that are different from aversive tasks. In this study, using an overexpression strategy as opposed to an inhibitor-based approach, we demonstrate an important modulatory role of PKMζ in synaptic plasticity and selective memory processing. Most of the literature investigating protein kinase Mζ (PKMζ) used inhibitors with selectivity that has been called into question or conventional knock-out animal

  17. Protein kinase D1 stimulates proliferation and enhances tumorigenesis of MCF-7 human breast cancer cells through a MEK/ERK-dependent signaling pathway

    International Nuclear Information System (INIS)

    Karam, Manale; Legay, Christine; Auclair, Christian; Ricort, Jean-Marc

    2012-01-01

    Protein kinase D1, PKD1, is a novel serine/threonine kinase whose altered expression and dysregulation in many tumors as well as its activation by several mitogens suggest that this protein could regulate proliferation and tumorigenesis. Nevertheless, the precise signaling pathways used are still unclear and the potential direct role of PKD1 in tumor development and progression has not been yet investigated. In order to clarify the role of PKD1 in cell proliferation and tumorigenesis, we studied the effects of PKD1 overexpression in a human adenocarcinoma breast cancer cell line, MCF-7 cells. We demonstrated that overexpression of PKD1 specifically promotes MCF-7 cell proliferation through accelerating G0/G1 to S phase transition of the cell cycle. Moreover, inhibition of endogenous PKD1 significantly reduced cell proliferation. Taken together, these results clearly strengthen the regulatory role of PKD1 in cell growth. We also demonstrated that overexpression of PKD1 specifically diminished serum- and anchorage-dependence for proliferation and survival in vitro and allowed MCF-7 cells to form tumors in vivo. Thus, all these data highlight the central role of PKD1 in biological processes which are hallmarks of malignant transformation. Analysis of two major signaling pathways implicated in MCF-7 cell proliferation showed that PKD1 overexpression significantly increased ERK1/2 phosphorylation state without affecting Akt phosphorylation. Moreover, PKD1 overexpression-stimulated cell proliferation and anchorage-independent growth were totally impaired by inhibition of the MEK/ERK kinase cascade. However, neither of these effects was affected by blocking the PI 3-kinase/Akt signaling pathway. Thus, the MEK/ERK signaling appears to be a determining pathway mediating the biological effects of PKD1 in MCF-7 cells. Taken together, all these data demonstrate that PKD1 overexpression increases the aggressiveness of MCF-7 breast cancer cells through enhancing their oncogenic

  18. Pharmacokinetics of intravitreal 5-flurouracil prodrugs in silicone oil. Experimental studies in pigs

    DEFF Research Database (Denmark)

    Laugesen, Caroline S; Steffansen, Bente; Scherfig, Erik

    2005-01-01

    PURPOSE: To examine the in vivo pharmacokinetics of intravitreal 5-Fluorouracil (5-FU) following tamponade with 5-FU prodrug silicone oil formulations. METHOD: Two different alkoxycarbonyl 5-FU prodrugs denoted C12 and C18 were synthesized and formulated as silicone oil suspensions. A total of 26...

  19. The efficacy of the anthracycline prodrug daunorubicin-GA3 in human ovarian cancer xenografts

    NARCIS (Netherlands)

    Houba, PHJ; Boven, E; Erkelens, CAM; Leenders, RGG; Scheeren, JW; Pinedo, HM; Haisma, HJ

    1998-01-01

    The prodrug N-[4-(daunorubicin-N-carbonyl-oxymethyl)phenyl] O-beta-glucuronyl carbamate (DNR-GA3) was synthesized for specific activation by human beta-glucuronidase, released in necrotic areas of tumour lesions. In vitro, DNR-GA3 was 18 times less toxic than daunorubicin (DNR) and the prodrug was

  20. Paclitaxel prodrugs, method for preparation as well as their use in selective chemotherapy

    NARCIS (Netherlands)

    de Bont, Hendricus BA; Leenders, Ruben GG; Scheeren, Johan W; Haisma, Hidde J; de Vos, Dick

    1998-01-01

    A paclitaxel prodrug has a paclitaxel portion coupled to a cleavable N-(aliphatic or aromatic)-O-glycosyl carbamate spacer group, and can be administered orally, topically or by injection to provide an anti-tumor effect, the prodrug being activated by a hydrolizing enzyme, an endogeneous enzyme or

  1. Pharmacological evaluation and preliminary pharmacokinetics studies of a new diclofenac prodrug without gastric ulceration effect.

    Science.gov (United States)

    Santos, Jean Leandro Dos; Moreira, Vanessa; Campos, Michel Leandro; Chelucci, Rafael Consolin; Barbieri, Karina Pereira; de Castro Souto, Pollyana Cristina Maggio; Matsubara, Márcio Hideki; Teixeira, Catarina; Bosquesi, Priscila Longhin; Peccinini, Rosângela Gonçalves; Chin, Chung Man

    2012-11-19

    Long-term nonsteroidal anti-inflammatory drugs (NSAIDs) therapy has been associated with several adverse effects such as gastric ulceration and cardiovascular events. Among the molecular modifications strategies, the prodrug approach is a useful tool to discover new safe NSAIDs. The 1-(2,6-dichlorophenyl)indolin-2-one is a diclofenac prodrug which demonstrated relevant anti-inflammatory properties without gastro ulceration effect. In addition, the prodrug decreases PGE(2) levels, COX-2 expression and cellular influx into peritoneal cavity induced by carrageenan treatment. Preliminary pharmacokinetic studies have shown in vivo bioconversion of prodrug to diclofenac. This prodrug is a new nonulcerogenic NSAID useful to treat inflammatory events by long-term therapy.

  2. Pharmacological Evaluation and Preliminary Pharmacokinetics Studies of a New Diclofenac Prodrug without Gastric Ulceration Effect

    Directory of Open Access Journals (Sweden)

    Chung Man Chin

    2012-11-01

    Full Text Available Long-term nonsteroidal anti-inflammatory drugs (NSAIDs therapy has been associated with several adverse effects such as gastric ulceration and cardiovascular events. Among the molecular modifications strategies, the prodrug approach is a useful tool to discover new safe NSAIDs. The 1-(2,6-dichlorophenylindolin-2-one is a diclofenac prodrug which demonstrated relevant anti-inflammatory properties without gastro ulceration effect. In addition, the prodrug decreases PGE2 levels, COX-2 expression and cellular influx into peritoneal cavity induced by carrageenan treatment. Preliminary pharmacokinetic studies have shown in vivo bioconversion of prodrug to diclofenac. This prodrug is a new nonulcerogenic NSAID useful to treat inflammatory events by long-term therapy.

  3. Chronic Ca2+ influx through voltage-dependent Ca2+ channels enhance delayed rectifier K+ currents via activating Src family tyrosine kinase in rat hippocampal neurons.

    Science.gov (United States)

    Yang, Yoon-Sil; Jeon, Sang-Chan; Kim, Dong-Kwan; Eun, Su-Yong; Jung, Sung-Cherl

    2017-03-01

    Excessive influx and the subsequent rapid cytosolic elevation of Ca 2+ in neurons is the major cause to induce hyperexcitability and irreversible cell damage although it is an essential ion for cellular signalings. Therefore, most neurons exhibit several cellular mechanisms to homeostatically regulate cytosolic Ca 2+ level in normal as well as pathological conditions. Delayed rectifier K + channels (I DR channels) play a role to suppress membrane excitability by inducing K + outflow in various conditions, indicating their potential role in preventing pathogenic conditions and cell damage under Ca 2+ -mediated excitotoxic conditions. In the present study, we electrophysiologically evaluated the response of I DR channels to hyperexcitable conditions induced by high Ca 2+ pretreatment (3.6 mM, for 24 hours) in cultured hippocampal neurons. In results, high Ca 2+ -treatment significantly increased the amplitude of I DR without changes of gating kinetics. Nimodipine but not APV blocked Ca 2+ -induced I DR enhancement, confirming that the change of I DR might be targeted by Ca 2+ influx through voltage-dependent Ca 2+ channels (VDCCs) rather than NMDA receptors (NMDARs). The VDCC-mediated I DR enhancement was not affected by either Ca 2+ -induced Ca 2+ release (CICR) or small conductance Ca 2+ -activated K + channels (SK channels). Furthermore, PP2 but not H89 completely abolished I DR enhancement under high Ca 2+ condition, indicating that the activation of Src family tyrosine kinases (SFKs) is required for Ca 2+ -mediated I DR enhancement. Thus, SFKs may be sensitive to excessive Ca 2+ influx through VDCCs and enhance I DR to activate a neuroprotective mechanism against Ca 2+ -mediated hyperexcitability in neurons.

  4. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A.

    1995-01-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs

  5. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A. [Henry Ford Hospital, Detroit, MI (United States)] [and others

    1995-11-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 {mu}g/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 {plus_minus} 0.1 and 1.3 {plus_minus} 0.1, respectively. Exposure of cells to 10 {mu}g/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 {plus_minus} 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs.

  6. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Jae, Ho Kim; Sang, Hie Kim; Kolozsvary, Andrew; Brown, Stephen L.; Ok, Bae Kim; Freytag, Svend O.

    1995-01-01

    Purpose: To demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Methods and Materials: Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses of irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. Results: The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. Conclusion: An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors

  7. Heat shock protein 90β stabilizes focal adhesion kinase and enhances cell migration and invasion in breast cancer cells

    International Nuclear Information System (INIS)

    Xiong, Xiangyang; Wang, Yao; Liu, Chengmei; Lu, Quqin; Liu, Tao; Chen, Guoan; Rao, Hai; Luo, Shiwen

    2014-01-01

    Focal adhesion kinase (FAK) acts as a regulator of cellular signaling and may promote cell spreading, motility, invasion and survival in malignancy. Elevated expression and activity of FAK frequently correlate with tumor cell metastasis and poor prognosis in breast cancer. However, the mechanisms by which the turnover of FAK is regulated remain elusive. Here we report that heat shock protein 90β (HSP90β) interacts with FAK and the middle domain (amino acids 233–620) of HSP90β is mainly responsible for this interaction. Furthermore, we found that HSP90β regulates FAK stability since HSP90β inhibitor 17-AAG triggers FAK ubiquitylation and subsequent proteasome-dependent degradation. Moreover, disrupted FAK-HSP90β interaction induced by 17-AAG contributes to attenuation of tumor cell growth, migration, and invasion. Together, our results reveal how HSP90β regulates FAK stability and identifies a potential therapeutic strategy to breast cancer. - Highlights: • HSP90β protects FAK from degradation by the ubiquitin-proteasome pathway. • Inhibition of HSP90β or FAK attenuates tumorigenesis of breast cancer cells. • Genetic repression of HSP90β or FAK inhibits tumor cell migration and proliferation. • Inhibition of HSP90β or FAK interferes cell invasion and cytoskeleton

  8. Aurora kinase inhibitors attached to iron oxide nanoparticles enhances inhibition of the growth of liver cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiquan [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Xie, Li [Southeast University, Zhongda Hospital, School of Medicine (China); Zheng, Ming; Yao, Juan [Jiangsu Chai Tai Tianqing Pharmaceutical Co. Ltd. (China); Song, Lina [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Chang, Weiwei [Jiangsu Chai Tai Tianqing Pharmaceutical Co. Ltd. (China); Zhang, Yu; Ji, Min, E-mail: minji888@hotmail.com; Gu, Ning, E-mail: guning@seu.edu.cn [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Zhan, Xi, E-mail: zhan01@gmail.com [University of Maryland School of Medicine, The Center of Vascular and Inflammatory Diseases, The Department of Pathology (United States)

    2015-06-15

    We have developed a novel Aurora kinase inhibitor (AKI) AM-005, an analogue of pan-AKI AT-9283. To improve the intracellular efficacy of AM-005 and AT-9283, we utilized magnetite nanoparticles (NPs) to deliver AM-005 and AT-9283 into human SMMC-7721 and HepG2 liver cancer cells. The drug-loaded NPs were prepared through quasi-emulsion solvent diffusion of magnetite NPs with AM-005 or AT-9283. The encapsulated drugs were readily released from NPs, preferentially at low pHs. Upon exposure, cancer cells effectively internalized drug-loaded NPs into lysosome-like vesicles, which triggered a series of cellular changes, including the formation of enlarged cytoplasm, the significant increase of membrane permeability, and the generation of reactive oxygen species (ROS). The increased ROS synthesis sustained over 72 h, whereas that in the cells treated with free-form drugs declined rapidly after 48 h. However, chemical sequestration of the iron core of NPs had a minor influence on the generation of intracellular ROS. On the other hand, uncoupling of AM-005 uptake with NP internalization into cells failed to induce ROS synthesis. Overall, our approach achieved two-fold increase in suppressing the viability of tumor cells in vitro and the growth of tumors in vivo. We conclude that magnetite NPs can be used as pH responsive nanocarriers that are able to improve the efficacy of AKIs.

  9. Heat shock protein 90β stabilizes focal adhesion kinase and enhances cell migration and invasion in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Xiangyang [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi 330006 (China); State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Wang, Yao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Liu, Chengmei [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Lu, Quqin [Department of Biostatistics and Epidemiology, School of Public Health, Nanchang University, Nanchang, Jiangxi 330006 (China); Liu, Tao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Chen, Guoan [Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006 (China); Rao, Hai [Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, TX 78229 (United States); Luo, Shiwen, E-mail: shiwenluo@ncu.edu.cn [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China)

    2014-08-01

    Focal adhesion kinase (FAK) acts as a regulator of cellular signaling and may promote cell spreading, motility, invasion and survival in malignancy. Elevated expression and activity of FAK frequently correlate with tumor cell metastasis and poor prognosis in breast cancer. However, the mechanisms by which the turnover of FAK is regulated remain elusive. Here we report that heat shock protein 90β (HSP90β) interacts with FAK and the middle domain (amino acids 233–620) of HSP90β is mainly responsible for this interaction. Furthermore, we found that HSP90β regulates FAK stability since HSP90β inhibitor 17-AAG triggers FAK ubiquitylation and subsequent proteasome-dependent degradation. Moreover, disrupted FAK-HSP90β interaction induced by 17-AAG contributes to attenuation of tumor cell growth, migration, and invasion. Together, our results reveal how HSP90β regulates FAK stability and identifies a potential therapeutic strategy to breast cancer. - Highlights: • HSP90β protects FAK from degradation by the ubiquitin-proteasome pathway. • Inhibition of HSP90β or FAK attenuates tumorigenesis of breast cancer cells. • Genetic repression of HSP90β or FAK inhibits tumor cell migration and proliferation. • Inhibition of HSP90β or FAK interferes cell invasion and cytoskeleton.

  10. The Flavin Reductase MsuE Is a Novel Nitroreductase that Can Efficiently Activate Two Promising Next-Generation Prodrugs for Gene-Directed Enzyme Prodrug Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Green, Laura K.; Storey, Mathew A. [School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington 6140 (New Zealand); Williams, Elsie M. [School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington 6140 (New Zealand); Victoria University Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Patterson, Adam V.; Smaill, Jeff B. [Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1142 (New Zealand); Auckland Cancer Society Research Centre, University of Auckland, Grafton, Auckland 1142 (New Zealand); Copp, Janine N.; Ackerley, David F., E-mail: david.ackerley@vuw.ac.nz [School of Biological Sciences, Victoria University of Wellington, Kelburn Parade, Wellington 6140 (New Zealand); Victoria University Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of Auckland, Auckland 1142 (New Zealand)

    2013-08-08

    Bacterial nitroreductase enzymes that can efficiently catalyse the oxygen-independent reduction of prodrugs originally developed to target tumour hypoxia offer great potential for expanding the therapeutic range of these molecules to aerobic tumour regions, via the emerging cancer strategy of gene-directed enzyme prodrug therapy (GDEPT). Two promising hypoxia prodrugs for GDEPT are the dinitrobenzamide mustard PR-104A, and the nitrochloromethylbenzindoline prodrug nitro-CBI-DEI. We describe here use of a nitro-quenched fluorogenic probe to identify MsuE from Pseudomonas aeruginosa as a novel nitroreductase candidate for GDEPT. In SOS and bacteria-delivered enzyme prodrug cytotoxicity assays MsuE was less effective at activating CB1954 (a first-generation GDEPT prodrug) than the “gold standard” nitroreductases NfsA and NfsB from Escherichia coli. However, MsuE exhibited comparable levels of activity with PR-104A and nitro-CBI-DEI, and is the first nitroreductase outside of the NfsA and NfsB enzyme families to do so. These in vitro findings suggest that MsuE is worthy of further evaluation in in vivo models of GDEPT.

  11. The Flavin Reductase MsuE Is a Novel Nitroreductase that Can Efficiently Activate Two Promising Next-Generation Prodrugs for Gene-Directed Enzyme Prodrug Therapy

    International Nuclear Information System (INIS)

    Green, Laura K.; Storey, Mathew A.; Williams, Elsie M.; Patterson, Adam V.; Smaill, Jeff B.; Copp, Janine N.; Ackerley, David F.

    2013-01-01

    Bacterial nitroreductase enzymes that can efficiently catalyse the oxygen-independent reduction of prodrugs originally developed to target tumour hypoxia offer great potential for expanding the therapeutic range of these molecules to aerobic tumour regions, via the emerging cancer strategy of gene-directed enzyme prodrug therapy (GDEPT). Two promising hypoxia prodrugs for GDEPT are the dinitrobenzamide mustard PR-104A, and the nitrochloromethylbenzindoline prodrug nitro-CBI-DEI. We describe here use of a nitro-quenched fluorogenic probe to identify MsuE from Pseudomonas aeruginosa as a novel nitroreductase candidate for GDEPT. In SOS and bacteria-delivered enzyme prodrug cytotoxicity assays MsuE was less effective at activating CB1954 (a first-generation GDEPT prodrug) than the “gold standard” nitroreductases NfsA and NfsB from Escherichia coli. However, MsuE exhibited comparable levels of activity with PR-104A and nitro-CBI-DEI, and is the first nitroreductase outside of the NfsA and NfsB enzyme families to do so. These in vitro findings suggest that MsuE is worthy of further evaluation in in vivo models of GDEPT

  12. Carrier-Mediated Prodrug Uptake to Improve the Oral Bioavailability of Polar Drugs: An Application to an Oseltamivir Analogue.

    Science.gov (United States)

    Incecayir, Tuba; Sun, Jing; Tsume, Yasuhiro; Xu, Hao; Gose, Tomoka; Nakanishi, Takeo; Tamai, Ikumi; Hilfinger, John; Lipka, Elke; Amidon, Gordon L

    2016-02-01

    The goal of this study was to improve the intestinal mucosal cell membrane permeability of the poorly absorbed guanidino analogue of a neuraminidase inhibitor, oseltamivir carboxylate (GOC) using a carrier-mediated strategy. Valyl amino acid prodrug of GOC with isopropyl-methylene-dioxy linker (GOC-ISP-Val) was evaluated as the potential substrate for intestinal oligopeptide transporter, hPEPT1 in Xenopus laevis oocytes heterologously expressing hPEPT1, and an intestinal mouse perfusion system. The diastereomers of GOC-ISP-Val were assessed for chemical and metabolic stability. Permeability of GOC-ISP-Val was determined in Caco-2 cells and mice. Diastereomer 2 was about 2 times more stable than diastereomer 1 in simulated intestinal fluid and rapidly hydrolyzed to the parent drug in cell homogenates. The prodrug had a 9 times-enhanced apparent permeability (P(app)) in Caco-2 cells compared with the parent drug. Both diastereomer exhibited high effective permeability (P(eff)) in mice, 6.32 ± 3.12 and 5.20 ± 2.81 × 10(-5) cm/s for diastereomer 1 and 2, respectively. GOC-ISP-Val was found to be a substrate of hPEPT1. Overall, this study indicates that the prodrug, GOC-ISP-Val, seems to be a promising oral anti-influenza agent that has sufficient stability at physiologically relevant pHs before absorption, significantly improved permeability via hPEPT1 and potentially rapid activation in the intestinal cells. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  13. Thapsigargin, origin, chemistry, structure-activity relationships and prodrug development

    DEFF Research Database (Denmark)

    Doan, Thi Quynh Nhu; Christensen, Søren Brøgger

    2015-01-01

    Thapsigargin was originally isolated from the roots of the Mediterranean umbelliferous plant Thapsia garganica in order to characterize the skin irritant principle. The biological activity was related to the subnanomolar affinity for the sarco-endoplasmic reticulum calcium ATPase. Prolonged......) targeted against prostate cancer. Conjugation to a peptide, which only is a substrate for prostate specific membrane antigen enabled development of a prodrug (G202), which is targeted towards a number of cancer diseases including hepatocellular carcinoma. G202 has under the name of mipsagargin in clinical...

  14. Supramolecular curcumin-barium prodrugs for formulating with ceramic particles.

    Science.gov (United States)

    Kamalasanan, Kaladhar; Anupriya; Deepa, M K; Sharma, Chandra P

    2014-10-01

    A simple and stable curcumin-ceramic combined formulation was developed with an aim to improve curcumin stability and release profile in the presence of reactive ceramic particles for potential dental and orthopedic applications. For that, curcumin was complexed with barium (Ba(2+)) to prepare curcumin-barium (BaCur) complex. Upon removal of the unbound curcumin and Ba(2+) by dialysis, a water-soluble BaCur complex was obtained. The complex was showing [M+1](+) peak at 10,000-20,000 with multiple fractionation peaks of MALDI-TOF-MS studies, showed that the complex was a supramolecular multimer. The (1)H NMR and FTIR studies revealed that, divalent Ba(2+) interacted predominantly through di-phenolic groups of curcumin to form an end-to-end complex resulted in supramolecular multimer. The overall crystallinity of the BaCur was lower than curcumin as per XRD analysis. The complexation of Ba(2+) to curcumin did not degrade curcumin as per HPLC studies. The fluorescence spectrum was blue shifted upon Ba(2+) complexation with curcumin. Monodisperse nanoparticles with size less than 200dnm was formed, out of the supramolecular complex upon dialysis, as per DLS, and upon loading into pluronic micelles the size was remaining in similar order of magnitude as per DLS and AFM studies. Stability of the curcumin was improved greater than 50% after complexation with Ba(2+) as per UV/Vis spectroscopy. Loading of the supramloecular nanoparticles into pluronic micelles had further improved the stability of curcumin to approx. 70% in water. These BaCur supramolecule nanoparticles can be considered as a new class of prodrugs with improved solubility and stability. Subsequently, ceramic nanoparticles with varying chemical composition were prepared for changing the material surface reactivity in terms of the increase in, degradability, surface pH and protein adsorption. Further, these ceramic particles were combined with curcumin prodrug formulations and optimized the curcumin release

  15. Polo-like kinase 1 (PLK1) inhibition suppresses cell growth and enhances radiation sensitivity in medulloblastoma cells

    International Nuclear Information System (INIS)

    Harris, Peter S; Foreman, Nicholas K; Vibhakar, Rajeev; Venkataraman, Sujatha; Alimova, Irina; Birks, Diane K; Donson, Andrew M; Knipstein, Jeffrey; Dubuc, Adrian; Taylor, Michael D; Handler, Michael H

    2012-01-01

    Medulloblastoma is the most common malignant brain tumor in children and remains a therapeutic challenge due to its significant therapy-related morbidity. Polo-like kinase 1 (PLK1) is highly expressed in many cancers and regulates critical steps in mitotic progression. Recent studies suggest that targeting PLK1 with small molecule inhibitors is a promising approach to tumor therapy. We examined the expression of PLK1 mRNA in medulloblastoma tumor samples using microarray analysis. The impact of PLK1 on cell proliferation was evaluated by depleting expression with RNA interference (RNAi) or by inhibiting function with the small molecule inhibitor BI 2536. Colony formation studies were performed to examine the impact of BI 2536 on medulloblastoma cell radiosensitivity. In addition, the impact of depleting PLK1 mRNA on tumor-initiating cells was evaluated using tumor sphere assays. Analysis of gene expression in two independent cohorts revealed that PLK1 mRNA is overexpressed in some, but not all, medulloblastoma patient samples when compared to normal cerebellum. Inhibition of PLK1 by RNAi significantly decreased medulloblastoma cell proliferation and clonogenic potential and increased cell apoptosis. Similarly, a low nanomolar concentration of BI 2536, a small molecule inhibitor of PLK1, potently inhibited cell growth, strongly suppressed the colony-forming ability, and increased cellular apoptosis of medulloblastoma cells. Furthermore, BI 2536 pretreatment sensitized medulloblastoma cells to ionizing radiation. Inhibition of PLK1 impaired tumor sphere formation of medulloblastoma cells and decreased the expression of SRY (sex determining region Y)-box 2 (SOX2) mRNA in tumor spheres indicating a possible role in targeting tumor inititiating cells. Our data suggest that targeting PLK1 with small molecule inhibitors, in combination with radiation therapy, is a novel strategy in the treatment of medulloblastoma that warrants further investigation

  16. Advanced Prodrug Strategies in Nucleoside and Non-Nucleoside Antiviral Agents: A Review of the Recent Five Years

    Directory of Open Access Journals (Sweden)

    Hanadi Sinokrot

    2017-10-01

    Full Text Available Background: Poor pharmacokinetic profiles and resistance are the main two drawbacks from which currently used antiviral agents suffer, thus make them excellent targets for research, especially in the presence of viral pandemics such as HIV and hepatitis C. Methods: The strategies employed in the studies covered in this review were sorted by the type of drug synthesized into ester prodrugs, targeted delivery prodrugs, macromolecular prodrugs, other nucleoside conjugates, and non-nucleoside drugs. Results: Utilizing the ester prodrug approach a novel isopropyl ester prodrug was found to be potent HIV integrase inhibitor. Further, employing the targeted delivery prodrug zanamivir and valine ester prodrug was made and shown a sole delivery of zanamivir. Additionally, VivaGel, a dendrimer macromolecular prodrug, was found to be very efficient and is now undergoing clinical trials. Conclusions: Of all the strategies employed (ester, targeted delivery, macromolecular, protides and nucleoside analogues, and non-nucleoside analogues prodrugs, the most promising are nucleoside analogues and macromolecular prodrugs. The macromolecular prodrug VivaGel works by two mechanisms: envelope mediated and receptor mediated disruption. Nucleotide analogues have witnessed productive era in the recent past few years. The era of non-interferon based treatment of hepatitis (through direct inhibitors of NS5A has dawned.

  17. Focal Adhesion Kinase Inhibitors in Combination with Erlotinib Demonstrate Enhanced Anti-Tumor Activity in Non-Small Cell Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Grant A Howe

    Full Text Available Blockade of epidermal growth factor receptor (EGFR activity has been a primary therapeutic target for non-small cell lung cancers (NSCLC. As patients with wild-type EGFR have demonstrated only modest benefit from EGFR tyrosine kinase inhibitors (TKIs, there is a need for additional therapeutic approaches in patients with wild-type EGFR. As a key component of downstream integrin signalling and known receptor cross-talk with EGFR, we hypothesized that targeting focal adhesion kinase (FAK activity, which has also been shown to correlate with aggressive stage in NSCLC, would lead to enhanced activity of EGFR TKIs. As such, EGFR TKI-resistant NSCLC cells (A549, H1299, H1975 were treated with the EGFR TKI erlotinib and FAK inhibitors (PF-573,228 or PF-562,271 both as single agents and in combination. We determined cell viability, apoptosis and 3-dimensional growth in vitro and assessed tumor growth in vivo. Treatment of EGFR TKI-resistant NSCLC cells with FAK inhibitor alone effectively inhibited cell viability in all cell lines tested; however, its use in combination with the EGFR TKI erlotinib was more effective at reducing cell viability than either treatment alone when tested in both 2- and 3-dimensional assays in vitro, with enhanced benefit seen in A549 cells. This increased efficacy may be due in part to the observed inhibition of Akt phosphorylation when the drugs were used in combination, where again A549 cells demonstrated the most inhibition following treatment with the drug combination. Combining erlotinib with FAK inhibitor was also potent in vivo as evidenced by reduced tumor growth in the A549 mouse xenograft model. We further ascertained that the enhanced sensitivity was irrespective of the LKB1 mutational status. In summary, we demonstrate the effectiveness of combining erlotinib and FAK inhibitors for use in known EGFR wild-type, EGFR TKI resistant cells, with the potential that a subset of cell types, which includes A549, could be

  18. Skeletal Muscle-specific G Protein-coupled Receptor Kinase 2 Ablation Alters Isolated Skeletal Muscle Mechanics and Enhances Clenbuterol-stimulated Hypertrophy.

    Science.gov (United States)

    Woodall, Benjamin P; Woodall, Meryl C; Luongo, Timothy S; Grisanti, Laurel A; Tilley, Douglas G; Elrod, John W; Koch, Walter J

    2016-10-14

    GRK2, a G protein-coupled receptor kinase, plays a critical role in cardiac physiology. Adrenergic receptors are the primary target for GRK2 activity in the heart; phosphorylation by GRK2 leads to desensitization of these receptors. As such, levels of GRK2 activity in the heart directly correlate with cardiac contractile function. Furthermore, increased expression of GRK2 after cardiac insult exacerbates injury and speeds progression to heart failure. Despite the importance of this kinase in both the physiology and pathophysiology of the heart, relatively little is known about the role of GRK2 in skeletal muscle function and disease. In this study we generated a novel skeletal muscle-specific GRK2 knock-out (KO) mouse (MLC-Cre:GRK2 fl/fl ) to gain a better understanding of the role of GRK2 in skeletal muscle physiology. In isolated muscle mechanics testing, GRK2 ablation caused a significant decrease in the specific force of contraction of the fast-twitch extensor digitorum longus muscle yet had no effect on the slow-twitch soleus muscle. Despite these effects in isolated muscle, exercise capacity was not altered in MLC-Cre:GRK2 fl/fl mice compared with wild-type controls. Skeletal muscle hypertrophy stimulated by clenbuterol, a β 2 -adrenergic receptor (β 2 AR) agonist, was significantly enhanced in MLC-Cre:GRK2 fl/fl mice; mechanistically, this seems to be due to increased clenbuterol-stimulated pro-hypertrophic Akt signaling in the GRK2 KO skeletal muscle. In summary, our study provides the first insights into the role of GRK2 in skeletal muscle physiology and points to a role for GRK2 as a modulator of contractile properties in skeletal muscle as well as β 2 AR-induced hypertrophy. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Skeletal Muscle-specific G Protein-coupled Receptor Kinase 2 Ablation Alters Isolated Skeletal Muscle Mechanics and Enhances Clenbuterol-stimulated Hypertrophy*

    Science.gov (United States)

    Woodall, Benjamin P.; Woodall, Meryl C.; Luongo, Timothy S.; Grisanti, Laurel A.; Tilley, Douglas G.; Elrod, John W.; Koch, Walter J.

    2016-01-01

    GRK2, a G protein-coupled receptor kinase, plays a critical role in cardiac physiology. Adrenergic receptors are the primary target for GRK2 activity in the heart; phosphorylation by GRK2 leads to desensitization of these receptors. As such, levels of GRK2 activity in the heart directly correlate with cardiac contractile function. Furthermore, increased expression of GRK2 after cardiac insult exacerbates injury and speeds progression to heart failure. Despite the importance of this kinase in both the physiology and pathophysiology of the heart, relatively little is known about the role of GRK2 in skeletal muscle function and disease. In this study we generated a novel skeletal muscle-specific GRK2 knock-out (KO) mouse (MLC-Cre:GRK2fl/fl) to gain a better understanding of the role of GRK2 in skeletal muscle physiology. In isolated muscle mechanics testing, GRK2 ablation caused a significant decrease in the specific force of contraction of the fast-twitch extensor digitorum longus muscle yet had no effect on the slow-twitch soleus muscle. Despite these effects in isolated muscle, exercise capacity was not altered in MLC-Cre:GRK2fl/fl mice compared with wild-type controls. Skeletal muscle hypertrophy stimulated by clenbuterol, a β2-adrenergic receptor (β2AR) agonist, was significantly enhanced in MLC-Cre:GRK2fl/fl mice; mechanistically, this seems to be due to increased clenbuterol-stimulated pro-hypertrophic Akt signaling in the GRK2 KO skeletal muscle. In summary, our study provides the first insights into the role of GRK2 in skeletal muscle physiology and points to a role for GRK2 as a modulator of contractile properties in skeletal muscle as well as β2AR-induced hypertrophy. PMID:27566547

  20. Concurrent Inhibition of Pim and FLT3 Kinases Enhances Apoptosis of FLT3-ITD Acute Myeloid Leukemia Cells through Increased Mcl-1 Proteasomal Degradation.

    Science.gov (United States)

    Kapoor, Shivani; Natarajan, Karthika; Baldwin, Patrick R; Doshi, Kshama A; Lapidus, Rena G; Mathias, Trevor J; Scarpa, Mario; Trotta, Rossana; Davila, Eduardo; Kraus, Manfred; Huszar, Dennis; Tron, Adriana E; Perrotti, Danilo; Baer, Maria R

    2018-01-01

    Purpose: fms -like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) is present in 30% of acute myeloid leukemia (AML), and these patients have short disease-free survival. FLT3 inhibitors have limited and transient clinical activity, and concurrent treatment with inhibitors of parallel or downstream signaling may improve responses. The oncogenic serine/threonine kinase Pim-1 is upregulated downstream of FLT3-ITD and also promotes its signaling in a positive feedback loop, suggesting benefit of combined Pim and FLT3 inhibition. Experimental Design: Combinations of clinically active Pim and FLT3 inhibitors were studied in vitro and in vivo Results: Concurrent treatment with the pan-Pim inhibitor AZD1208 and FLT3 inhibitors at clinically applicable concentrations abrogated in vitro growth of FLT3-ITD, but not wild-type FLT3 (FLT3-WT), cell lines. AZD1208 cotreatment increased FLT3 inhibitor-induced apoptosis of FLT3-ITD, but not FLT3-WT, cells measured by sub-G 1 fraction, annexin V labeling, mitochondrial membrane potential, and PARP and caspase-3 cleavage. Concurrent treatment with AZD1208 and the FLT3 inhibitor quizartinib decreased growth of MV4-11 cells, with FLT3-ITD, in mouse xenografts, and prolonged survival, enhanced apoptosis of FLT3-ITD primary AML blasts, but not FLT3-WT blasts or remission marrow cells, and decreased FLT3-ITD AML blast colony formation. Mechanistically, AZD1208 and quizartinib cotreatment decreased expression of the antiapoptotic protein Mcl-1. Decrease in Mcl-1 protein expression was abrogated by treatment with the proteasome inhibitor MG132, and was preceded by downregulation of the Mcl-1 deubiquitinase USP9X, a novel mechanism of Mcl-1 regulation in AML. Conclusions: The data support clinical testing of Pim and FLT3 inhibitor combination therapy for FLT3-ITD AML. Clin Cancer Res; 24(1); 234-47. ©2017 AACR . ©2017 American Association for Cancer Research.

  1. HCV NS5A protein containing potential ligands for both Src homology 2 and 3 domains enhances autophosphorylation of Src family kinase Fyn in B cells.

    Science.gov (United States)

    Nakashima, Kenji; Takeuchi, Kenji; Chihara, Kazuyasu; Horiguchi, Tomoko; Sun, Xuedong; Deng, Lin; Shoji, Ikuo; Hotta, Hak; Sada, Kiyonao

    2012-01-01

    Hepatitis C virus (HCV) infects B lymphocytes and induces mixed cryoglobulinemia and B cell non-Hodgkin's lymphoma. The molecular mechanism for the pathogenesis of HCV infection-mediated B cell disorders remains obscure. To identify the possible role for HCV nonstructural 5A (NS5A) protein in B cells, we generated the stable B cell lines expressing Myc-His tagged NS5A. Immunoprecipitation study in the presence or absence of pervanadate (PV) implied that NS5A was tyrosine phosphorylated by pervanadate (PV) treatment of the cells. Therefore we examined pull-down assay by using glutathione S-transferase (GST)-fusion proteins of various Src homology 2 (SH2) domains, which associates with phosphotyrosine within a specific amino acid sequence. The results showed that NS5A specifically bound to SH2 domain of Fyn from PV-treated B cells in addition to Src homology 3 (SH3) domain. Substitution of Arg(176) to Lys in the SH2 domain of Fyn abrogated this interaction. Deletion mutational analysis demonstrated that N-terminal region of NS5A was not required for the interaction with the SH2 domain of Fyn. Tyr(334) was identified as a tyrosine phosphorylation site in NS5A. Far-western analysis revealed that SH2 domain of Fyn directly bound to NS5A. Fyn and NS5A were colocalized in the lipid raft. These results suggest that NS5A directly binds to the SH2 domain of Fyn in a tyrosine phosphorylation-dependent manner. Lastly, we showed that the expression of NS5A in B cells increased phosphorylation of activation loop tyrosine in the kinase domain of Fyn. NS5A containing ligand for both SH2 and SH3 domains enhances an aberrant autophosphorylation and kinase activity of Fyn in B cells.

  2. HCV NS5A protein containing potential ligands for both Src homology 2 and 3 domains enhances autophosphorylation of Src family kinase Fyn in B cells.

    Directory of Open Access Journals (Sweden)

    Kenji Nakashima

    Full Text Available Hepatitis C virus (HCV infects B lymphocytes and induces mixed cryoglobulinemia and B cell non-Hodgkin's lymphoma. The molecular mechanism for the pathogenesis of HCV infection-mediated B cell disorders remains obscure. To identify the possible role for HCV nonstructural 5A (NS5A protein in B cells, we generated the stable B cell lines expressing Myc-His tagged NS5A. Immunoprecipitation study in the presence or absence of pervanadate (PV implied that NS5A was tyrosine phosphorylated by pervanadate (PV treatment of the cells. Therefore we examined pull-down assay by using glutathione S-transferase (GST-fusion proteins of various Src homology 2 (SH2 domains, which associates with phosphotyrosine within a specific amino acid sequence. The results showed that NS5A specifically bound to SH2 domain of Fyn from PV-treated B cells in addition to Src homology 3 (SH3 domain. Substitution of Arg(176 to Lys in the SH2 domain of Fyn abrogated this interaction. Deletion mutational analysis demonstrated that N-terminal region of NS5A was not required for the interaction with the SH2 domain of Fyn. Tyr(334 was identified as a tyrosine phosphorylation site in NS5A. Far-western analysis revealed that SH2 domain of Fyn directly bound to NS5A. Fyn and NS5A were colocalized in the lipid raft. These results suggest that NS5A directly binds to the SH2 domain of Fyn in a tyrosine phosphorylation-dependent manner. Lastly, we showed that the expression of NS5A in B cells increased phosphorylation of activation loop tyrosine in the kinase domain of Fyn. NS5A containing ligand for both SH2 and SH3 domains enhances an aberrant autophosphorylation and kinase activity of Fyn in B cells.

  3. Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) enhances IL-10 production through the activation of Bruton's tyrosine kinase and STAT3.

    Science.gov (United States)

    Incrocci, Ryan; Barse, Levi; Stone, Amanda; Vagvala, Sai; Montesano, Michael; Subramaniam, Vijay; Swanson-Mungerson, Michelle

    2017-01-01

    Previous data demonstrate that Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) enhances IL-10 to promote the survival of LMP2A-expressing B cell lymphomas. Since STAT3 is an important regulator of IL-10 production, we hypothesized that LMP2A activates a signal transduction cascade that increases STAT3 phosphorylation to enhance IL-10. Using LMP2A-negative and -positive B cell lines, the data indicate that LMP2A requires the early signaling molecules of the Syk/RAS/PI3K pathway to increase IL-10. Additional studies indicate that the PI3K-regulated kinase, BTK, is responsible for phosphorylating STAT3, which ultimately mediates the LMP2A-dependent increase in IL-10. These data are the first to show that LMP2A signaling results in STAT3 phosphorylation in B cells through a PI3K/BTK-dependent pathway. With the use of BTK and STAT3 inhibitors to treat B cell lymphomas in clinical trials, these findings highlight the possibility of using new pharmaceutical approaches to treat EBV-associated lymphomas that express LMP2A. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Monoclonal antibody Zt/g4 targeting RON receptor tyrosine kinase enhances chemosensitivity of bladder cancer cells to Epirubicin by promoting G1/S arrest and apoptosis.

    Science.gov (United States)

    Chen, Jun-Feng; Yu, Bi-Xia; Yu, Rui; Ma, Liang; Lv, Xiu-Yi; Cheng, Yue; Ma, Qi

    2017-02-01

    Epirubicin (EPI) is one of the most used intravesical chemotherapy agents after transurethral resection to non-muscle invasive bladder tumors (NMIBC) to prevent cancer recurrence and progression. However, even after resection of bladder tumors and intravesical chemotherapy, half of them will recur and progress. RON is a membrane tyrosine kinase receptor usually overexpressed in bladder cancer cells and associated with poor pathological features. This study aims to investigate the effects of anti-RON monoclonal antibody Zt/g4 on the chemosensitivity of bladder cells to EPI. After Zt/g4 treatment, cell cytotoxicity was significantly increased and cell invasion was markedly suppressed in EPI-treated bladder cancer cells. Further investigation indicated that combing Zt/g4 with EPI promoted cell G1/S-phase arrest and apoptosis, which are the potential mechanisms that RON signaling inhibition enhances chemosensitivity of EPI. Thus, combing antibody-based RON targeted therapy enhances the therapeutic effects of intravesical chemotherapy, which provides new strategy for further improvement of NMIBC patient outcomes.

  5. Hyperinsulinemia enhances interleukin-17-induced inflammation to promote prostate cancer development in obese mice through inhibiting glycogen synthase kinase 3-mediated phosphorylation and degradation of interleukin-17 receptor

    Science.gov (United States)

    Chen, Chong; Ge, Dongxia; Qu, Yine; Chen, Rongyi; Fan, Yi-Ming; Li, Nan; Tang, Wendell W.; Zhang, Wensheng; Zhang, Kun; Wang, Alun R.; Rowan, Brian G.; Hill, Steven M.; Sartor, Oliver; Abdel, Asim B.; Myers, Leann; Lin, Qishan; You, Zongbing

    2016-01-01

    Interleukin-17 (IL-17) plays important roles in inflammation, autoimmune diseases, and some cancers. Obese people are in a chronic inflammatory state with increased serum levels of IL-17, insulin, and insulin-like growth factor 1 (IGF1). How these factors contribute to the chronic inflammatory status that promotes development of aggressive prostate cancer in obese men is largely unknown. We found that, in obese mice, hyperinsulinemia enhanced IL-17-induced expression of downstream proinflammatory genes with increased levels of IL-17 receptor A (IL-17RA), resulting in development of more invasive prostate cancer. Glycogen synthase kinase 3 (GSK3) constitutively bound to and phosphorylated IL-17RA at T780, leading to ubiquitination and proteasome-mediated degradation of IL-17RA, thus inhibiting IL-17-mediated inflammation. IL-17RA phosphorylation was reduced, while the IL-17RA levels were increased in the proliferative human prostate cancer cells compared to the normal cells. Insulin and IGF1 enhanced IL-17-induced inflammatory responses through suppressing GSK3, which was shown in the cultured cell lines in vitro and obese mouse models of prostate cancer in vivo. These findings reveal a mechanism underlying the intensified inflammation in obesity and obesity-associated development of aggressive prostate cancer, suggesting that targeting GSK3 may be a potential therapeutic approach to suppress IL-17-mediated inflammation in the prevention and treatment of prostate cancer, particularly in obese men. PMID:26871944

  6. Hydrogen sulfide potentiates interleukin-1β-induced nitric oxide production via enhancement of extracellular signal-regulated kinase activation in rat vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Jeong, Sun-Oh; Pae, Hyun-Ock; Oh, Gi-Su; Jeong, Gil-Saeng; Lee, Bok-Soo; Lee, Seoul; Kim, Du Yong; Rhew, Hyun Yul; Lee, Kang-Min; Chung, Hun-Taeg

    2006-01-01

    Hydrogen sulfide (H 2 S) and nitric oxide (NO) are endogenously synthesized from L-cysteine and L-arginine, respectively. They might constitute a cooperative network to regulate their effects. In this study, we investigated whether H 2 S could affect NO production in rat vascular smooth muscle cells (VSMCs) stimulated with interleukin-1β (IL-1β). Although H 2 S by itself showed no effect on NO production, it augmented IL-β-induced NO production and this effect was associated with increased expression of inducible NO synthase (iNOS) and activation of nuclear factor (NF)-κB. IL-1β activated the extracellular signal-regulated kinase 1/2 (ERK1/2), and this activation was also enhanced by H 2 S. Inhibition of ERK1/2 activation by the selective inhibitor U0126 inhibited IL-1β-induced NF-κB activation, iNOS expression, and NO production either in the absence or presence of H 2 S. Our findings suggest that H 2 S enhances NO production and iNOS expression by potentiating IL-1β-induced NF-κB activation through a mechanism involving ERK1/2 signaling cascade in rat VSMCs

  7. The tyrosine kinase receptor Tyro3 enhances lifespan and neuropeptide Y (Npy neuron survival in the mouse anorexia (anx mutation

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    Dennis Y. Kim

    2017-05-01

    Full Text Available Severe appetite and weight loss define the eating disorder anorexia nervosa, and can also accompany the progression of some neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS. Although acute loss of hypothalamic neurons that produce appetite-stimulating neuropeptide Y (Npy and agouti-related peptide (Agrp in adult mice or in mice homozygous for the anorexia (anx mutation causes aphagia, our understanding of the factors that help maintain appetite regulatory circuitry is limited. Here we identify a mutation (C19T that converts an arginine to a tryptophan (R7W in the TYRO3 protein tyrosine kinase 3 (Tyro3 gene, which resides within the anx critical interval, as contributing to the severity of anx phenotypes. Our observation that, like Tyro3−/− mice, anx/anx mice exhibit abnormal secondary platelet aggregation suggested that the C19T Tyro3 variant might have functional consequences. Tyro3 is expressed in the hypothalamus and other brain regions affected by the anx mutation, and its mRNA localization appeared abnormal in anx/anx brains by postnatal day 19 (P19. The presence of wild-type Tyro3 transgenes, but not an R7W-Tyro3 transgene, doubled the weight and lifespans of anx/anx mice and near-normal numbers of hypothalamic Npy-expressing neurons were present in Tyro3-transgenic anx/anx mice at P19. Although no differences in R7W-Tyro3 signal sequence function or protein localization were discernible in vitro, distribution of R7W-Tyro3 protein differed from that of Tyro3 protein in the cerebellum of transgenic wild-type mice. Thus, R7W-Tyro3 protein localization deficits are only detectable in vivo. Further analyses revealed that the C19T Tyro3 mutation is present in a few other mouse strains, and hence is not the causative anx mutation, but rather an anx modifier. Our work shows that Tyro3 has prosurvival roles in the appetite regulatory circuitry and could also provide useful insights towards the development of interventions

  8. Specificity of a prodrug-activating enzyme hVACVase: the leaving group effect.

    Science.gov (United States)

    Sun, Jing; Dahan, Arik; Walls, Zachary F; Lai, Longsheng; Lee, Kyung-Dall; Amidon, Gordon L

    2010-12-06

    Human valacyclovirase (hVACVase) is a prodrug-activating enzyme for amino acid prodrugs including the antiviral drugs valacyclovir and valganciclovir. In hVACVase-catalyzed reactions, the leaving group of the substrate corresponds to the drug moiety of the prodrug, making the leaving group effect essential for the rational design of new prodrugs targeting hVACVase activation. In this study, a series of valine esters, phenylalanine esters, and a valine amide were characterized for the effect of the leaving group on the efficiency of hVACVase-mediated prodrug activation. Except for phenylalanine methyl and ethyl esters, all of the ester substrates exhibited a relatively high specificity constant (k(cat)/K(m)), ranging from 850 to 9490 mM(-1)·s(-1). The valine amide Val-3-APG exhibited significantly higher K(m) and lower k(cat) values compared to the corresponding ester Val-3-HPG, indicating poor specificity for hVACVase. In conclusion, the substrate leaving group has been shown to affect both binding and specific activity of hVACVase-catalyzed activation. It is proposed that hVACVase is an ideal target for α-amino acid ester prodrugs with relatively labile leaving groups while it is relatively inactivate toward amide prodrugs.

  9. Identification of novel nitroreductases from Bacillus cereus and their interaction with the CB1954 prodrug.

    Science.gov (United States)

    Gwenin, Vanessa V; Poornima, Paramasivan; Halliwell, Jennifer; Ball, Patrick; Robinson, George; Gwenin, Chris D

    2015-12-01

    Directed enzyme prodrug therapy is a form of cancer chemotherapy in which bacterial prodrug-activating enzymes, or their encoding genes, are directed to the tumour before administration of a prodrug. The prodrug can then be activated into a toxic drug at the tumour site, reducing off-target effects. The bacterial nitroreductases are a class of enzymes used in this therapeutic approach and although very promising, the low turnover rate of prodrug by the most studied nitroreductase enzyme, NfnB from Escherichia coli (NfnB_Ec), is a major limit to this technology. There is a continual search for enzymes with greater efficiency, and as part of the search for more efficient bacterial nitroreductase enzymes, two novel enzymes from Bacillus cereus (strain ATCC 14579) have been identified and shown to reduce the CB1954 (5-(aziridin-1-yl)-2,4-dinitrobenzamide) prodrug to its respective 2'-and 4'-hydroxylamine products. Both enzymes shared features characteristic of the nitro-FMN-reductase superfamily including non-covalently associated FMN, requirement for the NAD(P)H cofactor, homodimeric, could be inhibited by Dicoumarol (3,3'-methylenebis(4-hydroxy-2H-chromen-2-one)), and displayed ping pong bi bi kinetics. Based on the biochemical characteristics and nucleotide alignment with other nitroreductase enzymes, one enzyme was named YdgI_Bc and the other YfkO_Bc. Both B. cereus enzymes had greater turnover for the CB1954 prodrug compared with NfnB_Ec, and in the presence of added NADPH cofactor, YfkO_Bc had superior cell killing ability, and produced mainly the 4'-hydroxylamine product at low prodrug concentration. The YfkO_Bc was identified as a promising candidate for future enzyme prodrug therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Regulation of Pancreatic β Cell Mass by Cross-Interaction between CCAAT Enhancer Binding Protein β Induced by Endoplasmic Reticulum Stress and AMP-Activated Protein Kinase Activity.

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    Tomokazu Matsuda

    Full Text Available During the development of type 2 diabetes, endoplasmic reticulum (ER stress leads to not only insulin resistance but also to pancreatic beta cell failure. Conversely, cell function under various stressed conditions can be restored by reducing ER stress by activating AMP-activated protein kinase (AMPK. However, the details of this mechanism are still obscure. Therefore, the current study aims to elucidate the role of AMPK activity during ER stress-associated pancreatic beta cell failure. MIN6 cells were loaded with 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide (AICAR and metformin to assess the relationship between AMPK activity and CCAAT enhancer binding protein β (C/EBPβ expression levels. The effect of C/EBPβ phosphorylation on expression levels was also investigated. Vildagliptin and metformin were administered to pancreatic beta cell-specific C/EBPβ transgenic mice to investigate the relationship between C/EBPβ expression levels and AMPK activity in the pancreatic islets. When pancreatic beta cells are exposed to ER stress, the accumulation of the transcription factor C/EBPβ lowers the AMP/ATP ratio, thereby decreasing AMPK activity. In an opposite manner, incubation of MIN6 cells with AICAR or metformin activated AMPK, which suppressed C/EBPβ expression. In addition, administration of the dipeptidyl peptidase-4 inhibitor vildagliptin and metformin to pancreatic beta cell-specific C/EBPβ transgenic mice decreased C/EBPβ expression levels and enhanced pancreatic beta cell mass in proportion to the recovery of AMPK activity. Enhanced C/EBPβ expression and decreased AMPK activity act synergistically to induce ER stress-associated pancreatic beta cell failure.

  11. Engineering of lipid prodrug-based, hyaluronic acid-decorated nanostructured lipid carriers platform for 5-fluorouracil and cisplatin combination gastric cancer therapy

    Directory of Open Access Journals (Sweden)

    Qu CY

    2015-06-01

    Full Text Available Chun-Ying Qu,1,* Min Zhou,1,* Ying-wei Chen,2 Mei-mei Chen,3 Feng Shen,1 Lei-Ming Xu11Digestive Endoscopic Diagnosis and Treatment Center, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People’s Republic of China; 2Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, People’s Republic of China; 3Digestive Department, Xinhua Hospital, School of medicine, Shanghai Jiaotong University, Shanghai, People’s Republic of China*These authors contributed equally to this workPurpose: The first-line chemotherapy treatment protocol for gastric cancer is combination chemotherapy of 5-fluorouracil (5-FU and cisplatin (CDDP. The aim of this study was to engineer prodrug-based nanostructured lipid carriers (NLC platform for codelivery of 5-FU and CDDP to enhance therapy and decrease toxicity.Methods: First, 5-FU-stearic acid lipid conjugate was synthesized by two steps. Second, 5-FU-stearic acid prodrug and CDDP were loaded in NLC. Finally, hyaluronic acid (HA was coated onto NLC surface. Average size, zeta potential, and drug loading capacity of NLC were evaluated. Human gastric cancer cell line BGC823 (BGC823 cells was used for the testing of in vitro cytotoxicity assays. In vivo antitumor activity of NLC was evaluated in mice bearing BGC823 cells model.Results: HA-coated 5-FU-stearic acid prodrug and CDDP-loaded NLC (HA-FU/C-NLC showed a synergistic effect in combination therapy and displayed the greatest antitumor activity than all of the free drugs or uncoated NLC in vitro and in vivo.Conclusion: This work reveals that HA-coated NLC could be used as a novel carrier to codeliver 5-FU and CDDP for gastric cancer therapy. HA-FU/C-NLC could be a promising targeted and combinational therapy in nanomedicine.Keywords: gastric cancer, nanostructured lipid carriers, hyaluronic acid, combination chemotherapy, lipid prodrug

  12. Polychlorinated biphenyls (PCBs enhance metastatic properties of breast cancer cells by activating Rho-associated kinase (ROCK.

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    Sijin Liu

    Full Text Available BACKGROUND: Polychlorinated biphenyls (PCBs are a family of structurally related chlorinated aromatic hydrocarbons. Numerous studies have documented a wide spectrum of biological effects of PCBs on human health, such as immunotoxicity, neurotoxicity, estrogenic or antiestrogenic activity, and carcinogenesis. The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo, animal and epidemiologic studies. A number of investigations indicated that higher levels of PCBs in mammary tissues or sera correlated to breast cancer risk, and PCBs might be implicated in advancing breast cancer progression. METHODOLOGY/PRINCIPAL FINDINGS: In the current study, we for the first time report that PCBs greatly promote the ROCK activity and therefore increase cell motility for both non-metastatic and metastatic human breast cancer cells in vitro. In the in vivo study, PCBs significantly advance disease progression, leading to enhanced capability of metastatic breast cancer cells to metastasize to bone, lung and liver. Additionally, PCBs robustly induce the production of intracellular reactive oxygen species (ROS in breast cancer cells; ROS mechanistically elevate ROCK activity. CONCLUSIONS/SIGNIFICANCE: PCBs enhance the metastatic propensity of breast cancer cells by activating the ROCK signaling, which is dependent on ROS induced by PCBs. Inhibition of ROCK may stand for a unique way to restrain metastases in breast cancer upon PCB exposure.

  13. Celecoxib coupled to dextran via a glutamic acid linker yields a polymeric prodrug suitable for colonic delivery.

    Science.gov (United States)

    Lee, Yonghyun; Kim, Jungyun; Kim, Wooseong; Nam, Joon; Jeong, Seongkeun; Lee, Sunyoung; Yoo, Jin-Wook; Kim, Min-Soo; Jung, Yunjin

    2015-01-01

    Celecoxib, a selective cyclooxygenase-2 inhibitor, is potentially useful for the treatment of colonic diseases such as colorectal cancer and colitis. However, the cardiovascular toxicity of celecoxib limits its routine use in the clinic. Generally, colon-specific delivery of a drug both increases the therapeutic availability in the large intestine and decreases the systemic absorption of the drug, most likely resulting in enhanced therapeutic effects against colonic diseases such as colitis and reduced systemic side effects. To develop a colon-specific prodrug of celecoxib that could reduce its cardiovascular toxicity and improve its therapeutic activity, dextran-glutamic acid-celecoxib conjugate (glutam-1-yl celecoxib-dextran ester [G1CD]) was prepared and evaluated. While stable in pH 1.2 and 6.8 buffer solutions and small-intestinal contents, G1CD efficiently released celecoxib in cecal contents. Oral administration of G1CD to rats delivered a larger amount of celecoxib to the large intestine than free celecoxib. G1CD prevented the systemic absorption of celecoxib and did not decrease the serum level of 6-ketoprostaglandin F1α, an inverse indicator of cardiovascular toxicity of celecoxib. Collectively, G1CD may be a polymeric colon-specific celecoxib prodrug with therapeutic and toxicological advantages.

  14. T-Cell-Specific Loss of the PI-3-Kinase p110α Catalytic Subunit Results in Enhanced Cytokine Production and Antitumor Response

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    Laura Aragoneses-Fenoll

    2018-02-01

    Full Text Available Class IA phosphatidylinositol 3-kinase (PI3K catalytic subunits p110α and p110δ are targets in cancer therapy expressed at high levels in T lymphocytes. The role of p110δ PI3K in normal or pathological immune responses is well established, yet the importance of p110α subunits in T cell-dependent immune responses is not clear. To address this problem, mice with p110α conditionally deleted in CD4+ and CD8+ T lymphocytes (p110α−/−ΔT were used. p110α−/−ΔT mice show normal development of T cell subsets, but slightly reduced numbers of CD4+ T cells in the spleen. “In vitro,” TCR/CD3 plus CD28 activation of naive CD4+ and CD8+ p110α−/−ΔT T cells showed enhanced effector function, particularly IFN-γ secretion, T-bet induction, and Akt, Erk, or P38 activation. Tfh derived from p110α−/−ΔT cells also have enhanced responses when compared to normal mice, and IL-2 expanded p110α−/−ΔT CD8+ T cells had enhanced levels of LAMP-1 and Granzyme B. By contrast, the expansion of p110α−/−ΔT iTreg cells was diminished. Also, p110α−/−ΔT mice had enhanced anti-keyhole limpet hemocyanin (KLH IFN-γ, or IL-4 responses and IgG1 and IgG2b anti-KLH antibodies, using CFA or Alum as adjuvant, respectively. When compared to WT mice, p110α−/−ΔT mice inoculated with B16.F10 melanoma showed delayed tumor progression. The percentage of CD8+ T lymphocytes was higher and the percentage of Treg cells lower in the spleen of tumor-bearing p110α−/−ΔT mice. Also, IFN-γ production in tumor antigen-activated spleen cells was enhanced. Thus, PI3K p110α plays a significant role in antigen activation and differentiation of CD4+ and CD8+ T lymphocytes modulating antitumor immunity.

  15. Testin, a novel binding partner of the calcium-sensing receptor, enhances receptor-mediated Rho-kinase signalling

    International Nuclear Information System (INIS)

    Magno, Aaron L.; Ingley, Evan; Brown, Suzanne J.; Conigrave, Arthur D.; Ratajczak, Thomas; Ward, Bryan K.

    2011-01-01

    Highlights: → A yeast two-hybrid screen revealed testin bound to the calcium-sensing receptor. → The second zinc finger of LIM domain 1 of testin is critical for interaction. → Testin bound to a region of the receptor tail important for cell signalling. → Testin and receptor interaction was confirmed in mammalian (HEK293) cells. → Overexpression of testin enhanced receptor-mediated Rho signalling in HEK293 cells. -- Abstract: The calcium-sensing receptor (CaR) plays an integral role in calcium homeostasis and the regulation of other cellular functions including cell proliferation and cytoskeletal organisation. The multifunctional nature of the CaR is manifested through ligand-dependent stimulation of different signalling pathways that are also regulated by partner binding proteins. Following a yeast two-hybrid library screen using the intracellular tail of the CaR as bait, we identified several novel binding partners including the focal adhesion protein, testin. Testin has not previously been shown to interact with cell surface receptors. The sites of interaction between the CaR and testin were mapped to the membrane proximal region of the receptor tail and the second zinc-finger of LIM domain 1 of testin, the integrity of which was found to be critical for the CaR-testin interaction. The CaR-testin association was confirmed in HEK293 cells by coimmunoprecipitation and confocal microscopy studies. Ectopic expression of testin in HEK293 cells stably expressing the CaR enhanced CaR-stimulated Rho activity but had no effect on CaR-stimulated ERK signalling. These results suggest an interplay between the CaR and testin in the regulation of CaR-mediated Rho signalling with possible effects on the cytoskeleton.

  16. Abrogation of Antibody-Induced Arthritis in Mice by a Self-Activating Viridin Prodrug and Association With Impaired Neutrophil and Endothelial Cell Function

    Science.gov (United States)

    Stangenberg, Lars; Ellson, Chris; Cortez-Retamozo, Virna; Ortiz-Lopez, Adriana; Yuan, Hushan; Blois, Joseph; Smith, Ralph A.; Yaffe, Michael B.; Weissleder, Ralph; Benoist, Christophe; Mathis, Diane; Josephson, Lee; Mahmood, Umar

    2009-01-01

    Objective To test a novel self-activating viridin (SAV) prodrug that slowly releases wortmannin, a potent phosphoinositide 3-kinase inhibitor, in a model of antibody-mediated inflammatory arthritis. Methods The SAV prodrug was administered to K/BxN mice or to C57BL/6 (B6) mice that had been injected with K/BxN serum. Ankle thickness was measured, and histologic changes were scored after a 10-day disease course (serum-transfer arthritis). Protease activity was measured by a near-infrared imaging approach using a cleavable cathepsin–selective probe. Further near-infrared imaging techniques were used to analyze early changes in vascular permeability after serum injection, as well as neutrophil–endothelial cell interactions. Neutrophil functions were assessed using an oxidative burst assay as well as a degranulation assay. Results SAV prevented ankle swelling in mice with serum-transfer arthritis in a dose-dependent manner. It also markedly reduced the extent of other features of arthritis, such as protease activity and histology scores for inflammation and joint erosion. Moreover, SAV was an effective therapeutic agent. The underlying mechanisms for the antiinflammatory activity were manifold. Endothelial permeability after serum injection was reduced, as was firm neutrophil attachment to endothelial cells. Endothelial cell activation by tumor necrosis factor α was impeded by SAV, as measured by the expression of vascular cell adhesion molecule. Crucial neutrophil functions, such as generation of reactive oxygen species and degranulation of protease-laden vesicles, were decreased by SAV administration. Conclusion A novel SAV prodrug proved strongly antiinflammatory in a murine model of antibody-induced inflammatory arthritis. Its activity could be attributed, at least in part, to the inhibition of neutrophil and endothelial cell functions. PMID:19644878

  17. Human glutathione transferases catalyzing the bioactivation of anticancer thiopurine prodrugs.

    Science.gov (United States)

    Eklund, Birgitta I; Gunnarsdottir, Sjofn; Elfarra, Adnan A; Mannervik, Bengt

    2007-06-01

    cis-6-(2-Acetylvinylthio)purine (cAVTP) and trans-6-(2-acetylvinylthio)guanine (tAVTG) are thiopurine prodrugs provisionally inactivated by an alpha,beta-unsaturated substituent on the sulfur of the parental thiopurines 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG). The active thiopurines are liberated intracellularly by glutathione (GSH) in reactions catalyzed by glutathione transferases (GSTs) (EC 2.5.1.18). Catalytic activities of 13 human GSTs representing seven distinct classes of soluble GSTs have been determined. The bioactivation of cAVTP and tAVTG occurs via a transient addition of GSH to the activated double bond of the S-substituent of the prodrug, followed by elimination of the thiopurine. The first of these consecutive reactions is rate-limiting for thiopurine release, but GST-activation of this first addition is shifting the rate limitation to the subsequent elimination. Highly active GSTs reveal the transient intermediate, which is detectable by UV spectroscopy and HPLC analysis. LC/MS analysis of the reaction products demonstrates that the primary GSH conjugate, 4-glutathionylbuten-2-one, can react with a second GSH molecule to form the 4-(bis-glutathionyl)butan-2-one. GST M1-1 and GST A4-4 were the most efficient enzymes with tAVTG, and GST M1-1 and GST M2-2 had highest activity with cAVTP. The highly efficient GST M1-1 is polymorphic and is absent in approximately half of the human population. GST P1-1, which is overexpressed in many cancer cells, had no detectable activity with cAVTP and only minor activity with tAVTG. Other GST-activated prodrugs have targeted GST P1-1-expressing cancer cells. Tumors expressing high levels of GST M1-1 or GST A4-4 can be predicted to be particularly vulnerable to chemotherapy with cAVTP or tAVTG.

  18. Hypoxia-activated prodrug TH-302 decreased survival rate of canine lymphoma cells under hypoxic condition.

    Science.gov (United States)

    Yamazaki, Hiroki; Lai, Yu-Chang; Tateno, Morihiro; Setoguchi, Asuka; Goto-Koshino, Yuko; Endo, Yasuyuki; Nakaichi, Munekazu; Tsujimoto, Hajime; Miura, Naoki

    2017-01-01

    We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

  19. Ocular disposition of the hemiglutarate ester prodrug of ∆⁹-Tetrahydrocannabinol from various ophthalmic formulations.

    Science.gov (United States)

    Hingorani, Tushar; Adelli, Goutham R; Punyamurthula, Nagendra; Gul, Waseem; Elsohly, Mahmoud A; Repka, Michael A; Majumdar, Soumyajit

    2013-08-01

    The overall goal of this project is to enhance ocular delivery of ∆(9)-Tetrahydrocannabinol (THC) through the topical route. Solubility, stability and in vitro transcorneal permeability of the relatively hydrophilic hemiglutarate ester derivative, THC-HG, was studied in the presence of surfactants. The solutions were characterized with respect to micelle size, zeta potential and solution viscosity. In vivo studies were carried out in New Zealand albino rabbits. A previously reported promising THC-HG ion-pair formulation was also studied in vivo. Aqueous solubility and stability and in vitro transcorneal permeability of THC-HG was enhanced significantly in the presence of surfactants. THC levels in the ocular tissues (except cornea) were found to be below detection limits from mineral oil, surfactant or emulsion based formulations containing THC. In contrast, micellar and ion pair based THC-HG formulations produced significantly higher total THC concentrations in the anterior ocular chamber. In this study, although delivery of THC to the anterior chamber ocular tissues could be significantly increased through the prodrug and formulation approaches tested, further studies are needed to increase penetration to the back-of-the eye.

  20. Quantitative and Label-Free Detection of Protein Kinase A Activity Based on Surface-Enhanced Raman Spectroscopy with Gold Nanostars.

    Science.gov (United States)

    He, Shuai; Kyaw, Yi Mon Ei; Tan, Eddie Khay Ming; Bekale, Laurent; Kang, Malvin Wei Cherng; Kim, Susana Soo-Yeon; Tan, Ivan; Lam, Kong-Peng; Kah, James Chen Yong

    2018-04-26

    The activity of extracellular protein kinase A (PKA) is known to be a biomarker for cancer. However, conventional PKA assays based on colorimetric, radioactive, and fluorometric techniques suffer from intensive labeling-related preparations, background interference, photobleaching, and safety concerns. While surface-enhanced Raman spectroscopy (SERS)-based assays have been developed for various enzymes to address these limitations, their use in probing PKA activity is limited due to subtle changes in the Raman spectrum with phosphorylation. Here, we developed a robust colloidal SERS-based scheme for label-free quantitative measurement of PKA activity using gold nanostars (AuNS) as a SERS substrate functionalized with bovine serum albumin (BSA)-kemptide (Kem) bioconjugate (AuNS-BSA-Kem), where BSA conferred colloidal stability and Kem is a high-affinity peptide substrate for PKA. By performing principle component analysis (PCA) on the SERS spectrum, we identified two Raman peaks at 725 and 1395 cm -1 , whose ratiometric intensity change provided a quantitative measure of Kem phosphorylation by PKA in vitro and allowed us to distinguish MDA-MB-231 and MCF-7 breast cancer cells known to overexpress extracellular PKA catalytic subunits from noncancerous human umbilical vein endothelial cells (HUVEC) based on their PKA activity in cell culture supernatant. The outcome demonstrated potential application of AuNS-BSA-Kem as a SERS probe for cancer screening based on PKA activity.

  1. A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

    Science.gov (United States)

    Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

    2014-12-01

    Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  2. Tanshinone IIA increases the bystander effect of herpes simplex virus thymidine kinase/ganciclovir gene therapy via enhanced gap junctional intercellular communication.

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    Jianyong Xiao

    Full Text Available The bystander effect is an intriguing phenomenon by which adjacent cells become sensitized to drug treatment during gene therapy with herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV. This effect is reported to be mediated by gap junctional intercellular communication (GJIC, and therefore, we postulated that upregulation of genes that facilitate GJIC may enhance the HSV-tk/GCV bystander effect. Previous findings have shown Tanshinone IIA (Tan IIA, a chemical substance derived from a Chinese medicine herb, promotes the upregulation of the connexins Cx26 and Cx43 in B16 cells. Because gap junctions are formed by connexins, we hypothesized that Tan IIA might increase GJIC. Our results show that Tan IIA increased GJIC in B16 melanoma cells, leading to more efficient GCV-induced bystander killing in cells stably expressing HSV-tk. Additionally, in vivo experiments demonstrated that tumors in mice with 10% HSV-tk positive B16 cells and 90% wild-type B16 cells became smaller following treatment with the combination of GCV and Tan IIA as compared to GCV or Tan IIA alone. These data demonstrate that Tan IIA can augment the bystander effect of HSV-tk/GCV system through increased gap junction coupling, which adds strength to the promising strategy that develops connexins inducer to potentiate the effects of suicide gene therapy.

  3. Phosphoinositide 3-kinase accelerates postoperative tumor growth by inhibiting apoptosis and enhancing resistance to chemotherapy-induced apoptosis. Novel role for an old enemy.

    LENUS (Irish Health Repository)

    Coffey, J Calvin

    2012-02-03

    Tumor removal remains the principal treatment modality in the management of solid tumors. The process of tumor removal may potentiate the resurgent growth of residual neoplastic tissue. Herein, we describe a novel murine model in which flank tumor cytoreduction is followed by accelerated local tumor recurrence. This model held for primary and recurrent tumors generated using a panel of human and murine (LS174T, DU145, SW480, SW640, and 3LL) cell lines and replicated accelerated tumor growth following excisional surgery. In investigating this further, epithelial cells were purified from LS174T primary and corresponding recurrent tumors for comparison. Baseline as well as tumor necrosis factor apoptosis-inducing ligand (TRAIL)-induced apoptosis were significantly reduced in recurrent tumor epithelia. Primary and recurrent tumor gene expression profiles were then compared. This identified an increase and reduction in the expression of p110gamma and p85alpha class Ia phosphoinositide 3-kinase (PI3K) subunits in recurrent tumor epithelia. These changes were further confirmed at the protein level. The targeting of PI3K ex vivo, using LY294002, restored sensitivity to TRAIL in recurrent tumor epithelia. In vivo, adjuvant LY294002 prolonged survival and significantly attenuated recurrent tumor growth by greatly enhancing apoptosis levels. Hence, PI3K plays a role in generating the antiapoptotic and chemoresistant phenotype associated with accelerated local tumor recurrence.

  4. Casein kinases

    DEFF Research Database (Denmark)

    Issinger, O G

    1993-01-01

    The present review on casein kinases focuses mainly on the possible metabolic role of CK-2, with special emphasis on its behavior in pathological tissues. From these data at least three ways to regulate CK-2 activity emerge: (i) CK-2 activity changes during embryogenesis, being high at certain...

  5. Vitamin E Phosphate Nucleoside Prodrugs: A Platform for Intracellular Delivery of Monophosphorylated Nucleosides

    Directory of Open Access Journals (Sweden)

    Richard Daifuku

    2018-02-01

    Full Text Available Vitamin E phosphate (VEP nucleoside prodrugs are designed to bypass two mechanisms of tumor resistance to therapeutic nucleosides: nucleoside transport and kinase downregulation. Certain isoforms of vitamin E (VE have shown activity against solid and hematologic tumors and result in chemosensitization. Because gemcitabine is one of the most common chemotherapeutics for the treatment of cancer, it was used to demonstrate the constructs utility. Four different VE isoforms were conjugated with gemcitabine at the 5′ position. Two of these were δ-tocopherol-monophosphate (MP gemcitabine (NUC050 and δ-tocotrienol-MP gemcitabine (NUC052. NUC050 was shown to be able to deliver gemcitabine-MP intracellularly by a nucleoside transport independent mechanism. Its half-life administered IV in mice was 3.9 h. In a mouse xenograft model of non-small cell lung cancer (NSCLC NCI-H460, NUC050 at a dose of 40 mg/kg IV qwk × 4 resulted in significant inhibition to tumor growth on days 11–31 (p < 0.05 compared to saline control (SC. Median survival was 33 days (NUC050 vs. 25.5 days (SC ((hazard ratio HR = 0.24, p = 0.017. Further, NUC050 significantly inhibited tumor growth compared to historic data with gemcitabine at 135 mg/kg IV q5d × 3 on days 14–41 (p < 0.05. NUC052 was administered at a dose of 40 mg/kg IV qwk × 2 followed by 50 mg/kg qwk × 2. NUC052 resulted in inhibition to tumor growth on days 14–27 (p < 0.05 and median survival was 34 days (HR = 0.27, p = 0.033. NUC050 and NUC052 have been shown to be safe and effective in a mouse xenograft of NSCLC.

  6. Astaxanthin down-regulates Rad51 expression via inactivation of AKT kinase to enhance mitomycin C-induced cytotoxicity in human non-small cell lung cancer cells.

    Science.gov (United States)

    Ko, Jen-Chung; Chen, Jyh-Cheng; Wang, Tai-Jing; Zheng, Hao-Yu; Chen, Wen-Ching; Chang, Po-Yuan; Lin, Yun-Wei

    2016-04-01

    Astaxanthin has been demonstrated to exhibit a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. However, the molecular mechanism of astaxanthin-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination, and studies show that chemo-resistant carcinomas exhibit high levels of Rad51 expression. In this study, astaxanthin treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1703. Astaxanthin treatment (2.5-20 μM) decreased Rad51 expression and phospho-AKT(Ser473) protein level in a time and dose-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vector rescued the decreased Rad51 mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 or wortmannin) further decreased the Rad51 expression in astaxanthin-exposed A549 and H1703 cells. Knockdown of Rad51 expression by transfection with si-Rad51 RNA or cotreatment with LY294002 further enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Additionally, mitomycin C (MMC) as an anti-tumor antibiotic is widely used in clinical NSCLC chemotherapy. Combination of MMC and astaxanthin synergistically resulted in cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced phospho-AKT(Ser473) level and Rad51 expression. Overexpression of AKT-CA or Flag-tagged Rad51 reversed the astaxanthin and MMC-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in astaxanthin and MMC co-treated cells. In conclusion, astaxanthin enhances MMC-induced cytotoxicity by decreasing Rad51 expression and AKT activation. These findings may provide rationale to combine astaxanthin with MMC for the treatment of NSCLC. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Enhancing chemosensitivity to gemcitabine via RNA interference targeting the catalytic subunits of protein kinase CK2 in human pancreatic cancer cells

    International Nuclear Information System (INIS)

    Kreutzer, Jan N; Ruzzene, Maria; Guerra, Barbara

    2010-01-01

    Pancreatic cancer is a complex genetic disorder that is characterized by rapid progression, invasiveness, resistance to treatment and high molecular heterogeneity. Various agents have been used in clinical trials showing only modest improvements with respect to gemcitabine-based chemotherapy, which continues to be the standard first-line treatment for this disease. However, owing to the overwhelming molecular alterations that have been reported in pancreatic cancer, there is increasing focus on targeting molecular pathways and networks, rather than individual genes or gene-products with a combination of novel chemotherapeutic agents. Cells were transfected with small interfering RNAs (siRNAs) targeting the individual CK2 subunits. The CK2 protein expression levels were determined and the effect of its down-regulation on chemosensitization of pancreatic cancer cells was investigated. The present study examined the impact on cell death following depletion of the individual protein kinase CK2 catalytic subunits alone or in combination with gemcitabine and the molecular mechanisms by which this effect is achieved. Depletion of the CK2α or -α' subunits in combination with gemcitabine resulted in marked apoptotic and necrotic cell death in PANC-1 cells. We show that the mechanism of cell death is associated with deregulation of distinct survival signaling pathways. Cellular depletion of CK2α leads to phosphorylation and activation of MKK4/JNK while down-regulation of CK2α' exerts major effects on the PI3K/AKT pathway. Results reported here show that the two catalytic subunits of CK2 contribute differently to enhance gemcitabine-induced cell death, the reduced level of CK2α' being the most effective and that simultaneous reduction in the expression of CK2 and other survival factors might be an effective therapeutic strategy for enhancing the sensitivity of human pancreatic cancer towards chemotherapeutic agents

  8. Prodrug strategy for cancer cell-specific targeting: A recent overview.

    Science.gov (United States)

    Zhang, Xian; Li, Xiang; You, Qidong; Zhang, Xiaojin

    2017-10-20

    The increasing development of targeted cancer therapy provides extensive possibilities in clinical trials, and numerous strategies have been explored. The prodrug is one of the most promising strategies in targeted cancer therapy to improve the selectivity and efficacy of cytotoxic compounds. Compared with normal tissues, cancer cells are characterized by unique aberrant markers, thus inactive prodrugs targeting these markers are excellent therapeutics to release active drugs, killing cancer cells without damaging normal tissues. In this review, we explore an integrated view of potential prodrugs applied in targeted cancer therapy based on aberrant cancer specific markers and some examples are provided for inspiring new ideas of prodrug strategy for cancer cell-specific targeting. Copyright © 2017. Published by Elsevier Masson SAS.

  9. Esterase-sensitive sulfur dioxide prodrugs inspired by modified Julia olefination.

    Science.gov (United States)

    Wang, Wenyi; Wang, Binghe

    2017-09-12

    Sulfur dioxide (SO 2 ) is an endogenously produced gaseous molecule, and is emerging as a potential gasotransmitter. Herein, we describe the first series of esterase-sensitive prodrugs inspired by modified Julia olefination as SO 2 donors.

  10. Kinases and Cancer

    OpenAIRE

    Jonas Cicenas; Egle Zalyte; Amos Bairoch; Pascale Gaudet

    2018-01-01

    Protein kinases are a large family of enzymes catalyzing protein phosphorylation. The human genome contains 518 protein kinase genes, 478 of which belong to the classical protein kinase family and 40 are atypical protein kinases [...

  11. Synthesis and antimalarial evaluation of prodrugs of novel fosmidomycin analogues.

    Science.gov (United States)

    Faísca Phillips, Ana Maria; Nogueira, Fátima; Murtinheira, Fernanda; Barros, Maria Teresa

    2015-01-01

    The continuous development of drug resistance by Plasmodium falciparum, the agent responsible for the most severe forms of malaria, creates the need for the development of novel drugs to fight this disease. Fosmidomycin is an effective antimalarial and potent antibiotic, known to act by inhibiting the enzyme 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), essential for the synthesis of isoprenoids in eubacteria and plasmodia, but not in humans. In this study, novel constrained cyclic prodrug analogues of fosmidomycin were synthesized. One, in which the hydroxamate function is incorporated into a six-membered ring, was found have higher antimalarial activity than fosmidomycin against the chloroquine and mefloquine resistant P. falciparum Dd2 strain. In addition, it showed very low cytotoxicity against cultured human cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Phosphorylation of protein kinase C sites Ser42/44 decreases Ca2+-sensitivity and blunts enhanced length-dependent activation in response to protein kinase A in human cardiomyocytes

    NARCIS (Netherlands)

    Wijnker, P.J.M.; Sequeira Oliveira, V.; Witjas-Paalberends, E.R.; Foster, D.B.; dos Remedios, C.G.; Murphy, A.M.; Stienen, G.J.M.; van der Velden, J.

    2014-01-01

    Protein kinase C (PKC)-mediated phosphorylation of troponin I (cTnI) at Ser42/44 is increased in heart failure. While studies in rodents demonstrated that PKC-mediated Ser42/44 phosphorylation decreases maximal force and ATPase activity, PKC incubation of human cardiomyocytes did not affect maximal

  13. Preparation, characterization and in vitro evaluation of a new nucleotide analogue prodrug cyclodextrin inclusion complexes.

    OpenAIRE

    Diab , Roudayna; Jordheim , Lars P; Degobert , Ghania; Peyrottes , Suzanne; Périgaud , Christian; Dumontet , Charles; Fessi , Hatem

    2009-01-01

    International audience; Bis(tbutyl-S-acyl-2-thioethyl)-cytidine monophosophate is a new cytotoxic mononucleotide prodrug which have been developed to reverse the cellular resistance to nucleoside analogues. Unfortunately, its in vivo utilisation was hampered by its poor water solubility, raising the need of a molecular vector capable to mask its physicochemical characteristics although without affecting its cytotoxic activity. Hydroxypropyl-beta-cyclodextrin was used to prepare the prodrug in...

  14. Synthesis, characterization and in vitro release performance of the pegylated valnemulin prodrug

    Science.gov (United States)

    DONG, Xinrui; SHU, Xueye; WANG, Yingnan; NIU, Zhaohuan; XU, Shixia; ZHANG, Yue; ZHAO, Shuchun

    2017-01-01

    Valnemulin, successfully developed by Sandoz in 1984, is a new generation derivative of pleuromutilin related to tiamulin. Valnemulin has low water-solubility, a short half-life period, low bioavailability, and instability. The application of valnemulin was restricted. Therefore, finding a more moderate delivery system is necessary to improve the shortcomings of valnemulin. The purpose of the study was to improve the strong stability and the irritation caused by of valnemulin hydrochloride power through pegylated-valnemulin prodrug mode. The prepared pegylated-valnemulin prodrug was characterized and evaluated by in vitro release performance under buffer solutions with pH levels of 7.4 and 3.6. The loading rate of valnemulin in PEG-succinic-valnemulin prodrug was determined by ultraviolet spectrophotometer and high performance liquid chromatography (HPLC). HPLC with evaporative light scattering detector was applied to determine the amount of PEG-succinic acid. The loading rate of valnemulin in PEG-succinic-valnemulin prodrug was 6.46%. PEG-succinic-valnemulin prodrug demonstrated a satisfactory solubility of valnemulin with 523 mg·ml−1 and excellent stability verified by the stability experiment. The result of the in vitro release test showed that the prepared PEG-valnemulin prodrug has controlled release ability and the release rate of valnemulin from PEG-valnemulin prodrug with a pH of 7.4 was 64.98%, which was higher than that of pH3.6 with release rate of 31.90%. Therefore, the prepared PEG-succinic-valnemulin prodrug has great application potential. PMID:29187697

  15. Pt(IV) complexes as prodrugs for cisplatin.

    Science.gov (United States)

    Shi, Yi; Liu, Shu-An; Kerwood, Deborah J; Goodisman, Jerry; Dabrowiak, James C

    2012-02-01

    The antitumor effects of platinum(IV) complexes, considered prodrugs for cisplatin, are believed to be due to biological reduction of Pt(IV) to Pt(II), with the reduction products binding to DNA and other cellular targets. In this work we used pBR322 DNA to capture the products of reduction of oxoplatin, c,t,c-[PtCl(2)(OH)(2)(NH(3))(2)], 3, and a carboxylate-modified analog, c,t,c-[PtCl(2)(OH)(O(2)CCH(2)CH(2)CO(2)H)(NH(3))(2)], 4, by ascorbic acid (AsA) or glutathione (GSH). Since carbonate plays a significant role in the speciation of platinum complexes in solution, we also investigated the effects of carbonate on the reduction/DNA-binding process. In pH 7.4 buffer in the absence of carbonate, both 3 and 4 are reduced by AsA to cisplatin (confirmed using ((195))Pt NMR), which binds to and unwinds closed circular DNA in a manner consistent with the formation of the well-known 1, 2 intrastrand DNA crosslink. However, when GSH is used as the reducing agent for 3 and 4, ((195))Pt NMR shows that cisplatin is not produced in the reaction medium. Although the Pt(II) products bind to closed circular DNA, their effect on the mobility of Form I DNA is different from that produced by cisplatin. When physiological carbonate is present in the reduction medium, ((13))C NMR shows that Pt(II) carbonato complexes form which block or impede platinum binding to DNA. The results of the study vis-à-vis the ability of the Pt(IV) complexes to act as prodrugs for cisplatin are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Synthesis and biological evaluation of S-acyl-3-thiopropyl prodrugs of N-phosphonoacetyl-L-aspartate (PALA).

    Science.gov (United States)

    Gagnard, Valérie; Leydet, Alain; Le Mellay, Véronique; Aubenque, Marielle; Morère, Alain; Montero, Jean-Louis

    2003-10-01

    The synthesis of new prodrugs of PALA characterised by the presence of S-acyl-3-thiopropyl, as enzyme-labile groups on the phosphonate moiety of PALA, is reported. The cytotoxic activities of PALA prodrugs were determined against human cell line (SW1573 lung carcinoma cells). A number of prodrugs bearing S-pivaloyl as acyl groups displayed cytotoxic activity in the same order of magnitude of PALA.

  17. Drug Delivery by an Enzyme-Mediated Cyclization of a Lipid Prodrug with Unique Bilayer-Formation Properties

    DEFF Research Database (Denmark)

    Linderoth, Lars; Peters, Günther H.j.; Madsen, Robert

    2009-01-01

    Special delivery: Liposomal drug-delivery systems in which prodrugs are activated specifically by disease-associated enzymes have great potential for the treatment of severe diseases, such as cancer. A new type of phospholipid-based prodrug has the ability to form stable small unilamellar vesicle...... (see picture). Activation of the prodrug vesicles by the enzyme sPLA2 initiates a cyclization reaction, which leads to the release of the drug....

  18. Electrospun poly-l-lactide scaffold for the controlled and targeted delivery of a synthetically obtained Diclofenac prodrug to treat actinic keratosis.

    Science.gov (United States)

    Piccirillo, Germano; Bochicchio, Brigida; Pepe, Antonietta; Schenke-Layland, Katja; Hinderer, Svenja

    2017-04-01

    Actinic Keratosis' (AKs) are small skin lesions that are related to a prolonged sun-damage, which can develop into invasive squamous cell carcinoma (SCC) when left untreated. Effective, specific and well tolerable therapies to cure AKs are still of great interest. Diclofenac (DCF) is the current gold standard for the local treatment of AKs in terms of costs, effectiveness, side effects and tolerability. In this work, an electrospun polylactic acid (PLA) scaffold loaded with a synthetic DCF prodrug was developed and characterized. Specifically, the prodrug was successfully synthetized by binding DCF to a glycine residue via solid phase peptide synthesis (SPPS) and then incorporated in an electrospun PLA scaffold. The drug encapsulation was verified using multiphoton microscopy (MPM) and its scaffold release was spectrophotometrically monitored and confirmed with MPM. The scaffold was further characterized with scanning electron microscopy (SEM), tensile testing and contact angle measurements. Its biocompatibility was verified by performing a cell proliferation assay and compared to PLA scaffolds containing the same amount of DCF sodium salt (DCFONa). Finally, the effect of the electrospun scaffolds on human dermal fibroblasts (HDFs) morphology and metabolism was investigated by combining MPM with fluorescence lifetime imaging microscopy (FLIM). The obtained results suggest that the obtained scaffold could be suitable for the controlled and targeted delivery of the synthesized prodrug for the treatment of AKs. Electrospun scaffolds are of growing interest as materials for a controlled drug delivery. In this work, an electrospun polylactic acid scaffold containing a synthetically obtained Diclofenac prodrug is proposed as a novel substrate for the topical treatment of actinic keratosis. A controlled drug delivery targeted to the area of interest could enhance the efficacy of the therapy and favor the healing process. The prodrug was synthesized via solid phase

  19. Improved Protease-Targeting and Biopharmaceutical Properties of Novel Prodrugs of Ganciclovir.

    Science.gov (United States)

    Sun, Kefeng; Xu, Hao; Hilfinger, John L; Lee, Kyung-Dall; Provoda, Chester J; Sabit, Hairat; Amidon, Gordon L

    2018-02-05

    The prodrug strategy has been frequently employed as a chemical approach for overcoming the disadvantages of existing parent drugs. In this report, we synthesized four monoester prodrugs of ganciclovir, an anticytomegalovirus drug, and demonstrated their potential advantages in protease-targeted activation and biopharmaceutical profiles over the parent compound. We demonstrated that these four prodrugs of ganciclovir, i.e., N-benzyloxycarbonyl-(L)-alanine-ganciclovir (CbzAlaGCV), N-benzyloxycarbonyl-(α,l)-aminobutyric acid-ganciclovir (CbzAbuGCV), N-acetyl-(l)-phenylalanine-(l)-alanine-ganciclovir (AcPheAlaGCV), and N-acetyl-(l)-phenylalanine-(α,l)-aminobutyric acid-ganciclovir (AcPheAbuGCV), are hydrolytically activated by the protease of human cytomegalovirus (hCMV), a serine protease that possesses intrinsic esterase activities. CbzAlaGCV and AcPheAlaGCV were found to be activated at a higher rate by the hCMV protease than CbzAbuGCV and AcPheAbuGCV. These ganciclovir prodrugs could potentially be targeted to selective activation by the hCMV protease which is only present at the viral infection sites, thereby achieving higher efficacy and lower systemic toxicity. The tissue stability, cellular uptake, and trans-epithelial transport of these ganciclovir prodrugs were also characterized. The N-acetylated dipeptide prodrugs of ganciclovir were found to be generally more stable than Cbz-amino acid prodrugs in various tissue matrices. Among the four prodrug candidates, AcPheAbuGCV was the most stable in human cell homogenates, plasma, and pooled liver microsomes. AcPheAbuGCV also possessed a superior cellular uptake profile and permeability across epithelial cell monolayers. Since the targeting and selective activation of a prodrug is determined by not only its rate of hydrolysis catalyzed by the hCMV protease target but also its biopharmaceutical properties, i.e., oral absorption and systemic availability, AcPheAbuGCV is considered the best overall candidate among

  20. Synthesis and Biological Evaluation of Liguzinediol Mono- and Dual Ester Prodrugs as Promising Inotropic Agents

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2014-11-01

    Full Text Available The potent positive inotropic effect, together with the relatively low safety risk of liguzinediol (LZDO, relative to currently available inotropic drugs, has prompted us to intensively research and develop LZDO as a potent positive inotropic agent. In this study, to obtain LZDO alternatives for oral chronic administration, a series of long-chain fatty carboxylic mono- and dual-esters of LZDO were synthesized, and preliminarily evaluated for physicochemical properties and bioconversion. Enhanced lipophilic properties and decreased solubility of the prodrugs were observed as the side chain length increased. All esters showed conspicuous chemical stability in phosphate buffer (pH 7.4. Moreover, the enzymatic hydrolysis of esters in human plasma and human liver microsomes confirmed that the majority of esters were converted to LZDO, with release profiles that varied due to the size and structure of the side chain. In vivo pharmacokinetic studies following oral administration of monopivaloyl (M5, monodecyl (M10 and monododecyl (M12 esters demonstrated the evidently extended half-lives relative to LZDO dosed alone. In particular the monopivaloyl ester M5 exhibited an optimal pharmacokinetic profile with appropriate physiochemical characteristics.

  1. Molecular Basis of Prodrug Activation by Human Valacyclovirase, an [alpha]-Amino Acid Ester Hydrolase

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Longsheng; Xu, Zhaohui; Zhou, Jiahai; Lee, Kyung-Dall; Amidon, Gordon L. (Michigan)

    2008-07-08

    Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of {alpha}-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar to tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific {alpha}-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.

  2. The phosphoinositide 3-kinase α selective inhibitor BYL719 enhances the effect of the protein kinase C inhibitor AEB071 in GNAQ/GNA11-mutant uveal melanoma cells.

    Science.gov (United States)

    Musi, Elgilda; Ambrosini, Grazia; de Stanchina, Elisa; Schwartz, Gary K

    2014-05-01

    G-protein mutations are one of the most common mutations occurring in uveal melanoma activating the protein kinase C (PKC)/mitogen-activated protein kinase and phosphoinositide 3-kinase (PI3K)/AKT pathways. In this study, we described the effect of dual pathway inhibition in uveal melanoma harboring GNAQ and GNA11 mutations via PKC inhibition with AEB071 (sotrastaurin) and PI3K/AKT inhibition with BYL719, a selective PI3Kα inhibitor. Growth inhibition was observed in GNAQ/GNA11-mutant cells with AEB071 versus no activity in wild-type cells. In the GNAQ-mutant cells, AEB071 decreased phosphorylation of myristoylated alanine-rich C-kinase substrate, a substrate of PKC, along with ERK1/2 and ribosomal S6, but persistent AKT activation was present. BYL719 had minimal antiproliferative activity in all uveal melanoma cell lines, and inhibited phosphorylation of AKT in most cell lines. In the GNA11-mutant cell line, similar effects were observed with ERK1/2 inhibition, mostly inhibited by BYL719. With the combination treatment, both GNAQ- and GNA11-mutant cell lines showed synergistic inhibition of cell proliferation and apoptotic cell death. In vivo studies correlated with in vitro findings showing reduced xenograft tumor growth with the combination therapy in a GNAQ-mutant model. These findings suggest a new therapy treatment option for G-protein-mutant uveal melanoma with a focus on specific targeting of multiple downstream pathways as part of combination therapy.

  3. IL-6 stabilizes Twist and enhances tumor cell motility in head and neck cancer cells through activation of casein kinase 2.

    Directory of Open Access Journals (Sweden)

    Ying-Wen Su

    Full Text Available BACKGROUND: Squamous cell carcinoma of the head and neck (SCCHN is the seventh most common cancer worldwide. Unfortunately, the survival of patients with SCCHN has not improved in the last 40 years, and thus new targets for therapy are needed. Recently, elevations in serum level of interleukin 6 (IL-6 and expression of Twist in tumor samples were found to be associated with poor clinical outcomes in multiple types of cancer, including SCCHN. Although Twist has been proposed as a master regulator of epithelial-mesenchymal transition and metastasis in cancers, the mechanisms by which Twist levels are regulated post-translationally are not completely understood. Tumor progression is characterized by the involvement of cytokines and growth factors and Twist induction has been connected with a number of these signaling pathways including IL-6. Since many of the effects of IL-6 are mediated through activation of protein phosphorylation cascades, this implies that Twist expression must be under a tight control at the post-translational level in order to respond in a timely manner to external stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Our data show that IL-6 increases Twist expression via a transcription-independent mechanism in many SCCHN cell lines. Further investigation revealed that IL-6 stabilizes Twist in SCCHN cell lines through casein kinase 2 (CK2 phosphorylation of Twist residues S18 and S20, and that this phosphorylation inhibits degradation of Twist. Twist phosphorylation not only increases its stability but also enhances cell motility. Thus, post-translational modulation of Twist contributes to its tumor-promoting properties. CONCLUSIONS/SIGNIFICANCE: Our study shows Twist expression can be regulated at the post-translational level through phosphorylation by CK2, which increases Twist stability in response to IL-6 stimulation. Our findings not only provide novel mechanistic insights into post-translational regulation of Twist but also suggest

  4. TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.

    Science.gov (United States)

    Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

    2013-08-01

    Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat.

  5. The Phosphoinositide 3-Kinaseα Selective Inhibitor, BYL719, Enhances the Effect of the Protein Kinase C Inhibitor, AEB071, in GNAQ/GNA11 Mutant Uveal Melanoma Cells

    Science.gov (United States)

    Musi, Elgilda; Ambrosini, Grazia; de Stanchina, Elisa; Schwartz, Gary K.

    2014-01-01

    G-protein mutations are one of the most common mutations occurring in uveal melanoma activating the protein kinase C (PKC)/mitogen-activated protein kinase (MAPK) and phosphoinositide 3-Kinase (PI3K)/AKT pathways. In this study, we described the effect of dual pathway inhibition in uveal melanoma harboring GNAQ and GNA11 mutations via PKC inhibition with AEB071 (Sotrastaurin) and PI3k/AKT inhibition with BYL719, a selective PI3Kα inhibitor. Growth inhibition was observed in GNAQ/GNA11 mutant cells with AEB071 versus no activity in WT cells. In the GNAQ-mutant cells, AEB071 decreased phosphorylation of MARCKS, a substrate of PKC, along with ERK1/2 and ribosomal S6, but persistent AKT activation was present. BYL719 had minimal anti-proliferative activity in all uveal melanoma cell lines, and inhibited phosphorylation of AKT in most cell lines. In the GNA11 mutant cell line, similar effects were observed with ERK1/2 inhibition, mostly inhibited by BYL719. With the combination treatment, both GNAQ and GNA11 mutant cell lines showed synergistic inhibition of cell proliferation and apoptotic cell death. In vivo studies correlated with in vitro findings showing reduced xenograft tumor growth with the combination therapy in a GNAQ mutant model. These findings suggest a new therapy treatment option for G-protein mutant uveal melanoma with a focus on specific targeting of multiple downstream pathways as part of combination therapy. PMID:24563540

  6. Selection of suitable prodrug candidates for in vivo studies via in vitro studies; the correlation of prodrug stability in between cell culture homogenates and human tissue homogenates.

    Science.gov (United States)

    Tsume, Yasuhiro; Amidon, Gordon L

    2012-01-01

    To determine the correlations/discrepancies of drug stabilities between in the homogenates of human culture cells and of human tissues. Amino acid/dipeptide monoester prodrugs of floxuridine were chosen as the model drugs. The stabilities (half-lives) of floxuridine prodrugs in human tissues (pancreas, liver, and small intestine) homogenates were obtained and compared with ones in cell culture homogenates (AcPC-1, Capan-2, and Caco-2 cells) as well as human liver microsomes. The correlations of prodrug stability in human small bowel tissue homogenate vs. Caco-2 cell homogenate, human liver tissue homogenate vs. human liver microsomes, and human pancreatic tissue homogenate vs. pancreatic cell, AsPC-1 and Capan-2, homogenates were examined. The stabilities of floxuridine prodrugs in human small bowel homogenate exhibited the great correlation to ones in Caco-2 cell homogenate (slope = 1.0-1.3, r2 = 0.79-0.98). The stability of those prodrugs in human pancreas tissue homogenate also exhibited the good correlations to ones in AsPC-1 and Capan-2 cells homogenates (slope = 0.5-0.8, r2 = 0.58-0.79). However, the correlations of prodrug stabilities between in human liver tissue homogenates and in human liver microsomes were weaker than others (slope = 1.3-1.9, r2 = 0.07-0.24). The correlations of drug stabilities in cultured cell homogenates and in human tissue homogenates were compared. Those results exhibited wide range of correlations between in cell homogenate and in human tissue homogenate (r2 = 0.07 - 0.98). Those in vitro studies in cell homogenates would be good tools to predict drug stabilities in vivo and to select drug candidates for further developments. In the series of experiments, 5'-O-D-valyl-floxuridine and 5'-O-L-phenylalanyl-L-tyrosyl-floxuridine would be selected as candidates of oral drug targeting delivery for cancer chemotherapy due to their relatively good stabilities compared to other tested prodrugs.

  7. Utilizing native fluorescence imaging, modeling and simulation to examine pharmacokinetics and therapeutic regimen of a novel anticancer prodrug

    International Nuclear Information System (INIS)

    Wang, Jing-Hung; Endsley, Aaron N.; Green, Carol E.; Matin, A. C.

    2016-01-01

    Success of cancer prodrugs relying on a foreign gene requires specific delivery of the gene to the cancer, and improvements such as higher level gene transfer and expression. Attaining these objectives will be facilitated in preclinical studies using our newly discovered CNOB-GDEPT, consisting of the produrg: 6-chloro-9-nitro-5-oxo-5H-benzo-(a)-phenoxazine (CNOB) and its activating enzyme ChrR6, which generates the cytotoxic product 9-amino-6-chloro-5H-benzo[a]phenoxazine-5-one (MCHB). MCHB is fluorescent and can be noninvasively imaged in mice, and here we investigated whether MCHB fluorescence quantitatively reflects its concentration, as this would enhance its reporter value in further development of the CNOB-GDEPT therapeutic regimen. PK parameters were estimated and used to predict more effective CNOB administration schedules. CNOB (3.3 mg/kg) was injected iv in mice implanted with humanized ChrR6 (HChrR6)-expressing 4T1 tumors. Fluorescence was imaged in live mice using IVIS Spectrum, and quantified by Living Image 3.2 software. MCHB and CNOB were quantified also by LC/MS/MS analysis. We used non-compartmental model to estimate PK parameters. Phoenix WinNonlin software was used for simulations to predict a more effective CNOB dosage regimen. CNOB administration significantly prolonged mice survival. MCHB fluorescence quantitatively reflected its exposure levels to the tumor and the plasma, as verified by LC/MS/MS analysis at various time points, including at a low concentration of 2 ng/g tumor. The LC/MS/MS data were used to estimate peak plasma concentrations, exposure (AUC 0-24 ), volume of distribution, clearance and half-life in plasma and the tumor. Simulations suggested that the CNOB-GDEPT can be a successful therapy without large increases in the prodrug dosage. MCHB fluorescence quantifies this drug, and CNOB can be effective at relatively low doses. MCHB fluorescence characteristics will expedite further development of CNOB-GDEPT by, for example

  8. Stabilization of the nitric oxide (NO) prodrugs and anticancer leads, PABA/NO and Double JS-K, through incorporation into PEG-protected nanoparticles.

    Science.gov (United States)

    Kumar, Varun; Hong, Sam Y; Maciag, Anna E; Saavedra, Joseph E; Adamson, Douglas H; Prud'homme, Robert K; Keefer, Larry K; Chakrapani, Harinath

    2010-02-01

    We report the stabilization of the nitric oxide (NO) prodrugs and anticancer lead compounds, PABA/NO (O(2)-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and "Double JS-K" 1,5-bis-{1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato}-2,4-dinitrobenzene, through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO are protected from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit.

  9. Preparation, characterization and in vitro evaluation of a new nucleotide analogue prodrug cyclodextrin inclusion complexes.

    Science.gov (United States)

    Diab, Roudayna; Jordheim, Lars P; Degobert, Ghania; Peyrottes, Suzanne; Périgaud, Christian; Dumontet, Charles; Fessi, Hatem

    2009-01-01

    Bis(tbutyl-S-acyl-2-thioethyl)-cytidine monophosophate is a new cytotoxic mononucleotide prodrug which have been developed to reverse the cellular resistance to nucleoside analogues. Unfortunately, its in vivo utilisation was hampered by its poor water solubility, raising the need of a molecular vector capable to mask its physicochemical characteristics although without affecting its cytotoxic activity. Hydroxypropyl-beta-cyclodextrin was used to prepare the prodrug inclusion complexes, allowing it to be solubilized in water and hence to be used for in vitro and in vivo experiments. A molar ratio of the cyclodextrin: prodrug of 3 was sufficient to obtain complete solubilization of the prodrug. The inclusion complex was characterized by differential scanning calorimetry, which revealed the disappearance of the melting peak of the prodrug suggesting the formation of inclusion complex. Proton Nuclear Magnetic Resonance spectroscopy provided a definitive proof of the inclusion complex formation, which was evidenced by the large chemical shift displacements observed for protons located in the interior of the hydrophobic cyclodextrin cavity. The complex retained its cytotoxic activity as shown by in vitro cell survival assays on murine leukemia cells. These results provided a basis for potential therapeutic applications of co-formulation of this new nucleotide analogue with hydroxypropyl-beta-CD in cancer therapy.

  10. Formulation and evaluation of co-prodrug of flurbiprofen and methocarbamol

    Directory of Open Access Journals (Sweden)

    Neela Bhatia

    2016-06-01

    Full Text Available The current work envisages synthesis of an ester prodrug of flurbiprofen whereby its carboxylic group was condensed with a skeletal muscle relaxant methocarbamol, with the aim of synergistic activity of two drugs, avoid flurbiprofen mediated gastro-intestinal damage and minimize the ulceration tendency of flurbiprofen. The synthesized prodrug was characterized and confirmed by physicochemical and spectroscopic studies. Solubility and partition coefficient studies indicated an increased lipophilicity and thus better suitability for oral administration than the parent drugs and the protein binding studies revealed a low protein binding capacity of the mutual prodrug. Subsequently, in-vitro hydrolysis was studied in different pH, simulated gastric fluid, simulated intestinal fluid and plasma and quantitative evaluation was performed by high performance liquid chromatography. It was found that the prodrug remained unhydrolyzed in the stomach after absorption however, underwent rapid cleavage by the esterases in blood to give the parent drug. Furthermore, the mutual ester prodrug was evaluated for its anti-inflammatory, analgesic, skeletal muscle relaxation, ulcerogenic and total acid content activity and was found to possess comparable activity with that of the parent drugs. Microscopic structures of the stomach tissues revealed significant reduction in gastric ulcer formation of mice gastric mucosa as compared to parent carboxylic acid drug.

  11. Delivery of Gemcitabine Prodrugs Employing Mesoporous Silica Nanoparticles

    Directory of Open Access Journals (Sweden)

    Alessio Malfanti

    2016-04-01

    Full Text Available In this paper, mesoporous silica nanoparticles (MSNs were studied as vehicles for the delivery of the antitumoral drug gemcitabine (GEM and of its 4-(N-acyl derivatives, (4-(N-valeroyl-(C5GEM, 4-(N-lauroyl-(C12GEM and 4-(N-stearoyl-gemcitabine (C18GEM. The loading of the GEM lipophilic prodrugs on MSNs was explored with the aim to obtain both a physical and a chemical protection of GEM from rapid plasmatic metabolization. For this purpose, MSNs as such or with grafted aminopropyl and carboxyethyl groups were prepared and characterized. Then, their different drug loading capacity in relation to the nature of the functional group was evaluated. In our experimental conditions, GEM was not loaded in any MSNs, while C12GEM was the most efficiently encapsulated and employed for further evaluation. The results showed that loading capacity increased with the presence of functional groups on the nanoparticles; similarly, the presence of functional groups on MSNs’ surface influenced the drug release profile. Finally, the cytotoxicity of the different preparations was evaluated and data showed that C12GEM loaded MSNs are less cytotoxic than the free drug with an activity that increased with the incubating time, indicating that all these systems are able to release the drug in a controlled manner. Altogether, the results demonstrate that these MSNs could be an interesting system for the delivery of anticancer drugs.

  12. Myosin light chain kinase is necessary for post-shock mesenteric lymph drainage enhancement of vascular reactivity and calcium sensitivity in hemorrhagic-shocked rats

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.P.; Niu, C.Y.; Zhao, Z.G.; Zhang, L.M.; Si, Y.H. [Institute of Microcirculation, Hebei North University, Hebei (China)

    2013-08-10

    Vascular hyporeactivity is an important factor in irreversible shock, and post-shock mesenteric lymph (PSML) blockade improves vascular reactivity after hemorrhagic shock. This study explored the possible involvement of myosin light chain kinase (MLCK) in PSML-mediated vascular hyporeactivity and calcium desensitization. Rats were divided into sham (n=12), shock (n=18), and shock+drainage (n=18) groups. A hemorrhagic shock model (40±2 mmHg, 3 h) was established in the shock and shock+drainage groups. PSML drainage was performed from 1 to 3 h from start of hypotension in shock+drainage rats. Levels of phospho-MLCK (p-MLCK) were determined in superior mesenteric artery (SMA) tissue, and the vascular reactivity to norepinephrine (NE) and sensitivity to Ca{sup 2+} were observed in SMA rings in an isolated organ perfusion system. p-MLCK was significantly decreased in the shock group compared with the sham group, but increased in the shock+drainage group compared with the shock group. Substance P (1 nM), an agonist of MLCK, significantly elevated the decreased contractile response of SMA rings to both NE and Ca{sup 2+} at various concentrations. Maximum contractility (E{sub max}) in the shock group increased with NE (from 0.179±0.038 to 0.440±0.177 g/mg, P<0.05) and Ca{sup 2+} (from 0.515±0.043 to 0.646±0.096 g/mg, P<0.05). ML-7 (0.1 nM), an inhibitor of MLCK, reduced the increased vascular response to NE and Ca{sup 2+} at various concentrations in the shock+drainage group (from 0.744±0.187 to 0.570±0.143 g/mg in E{sub max} for NE and from 0.729±0.037 to 0.645±0.056 g/mg in E{sub max} for Ca{sup 2+}, P<0.05). We conclude that MLCK is an important contributor to PSML drainage, enhancing vascular reactivity and calcium sensitivity in rats with hemorrhagic shock.

  13. Flurbiprofen–antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling

    Science.gov (United States)

    Ashraf, Zaman; Alamgeer; Kanwal, Munazza; Hassan, Mubashir; Abdullah, Sahar; Waheed, Mamuna; Ahsan, Haseeb; Kim, Song Ja

    2016-01-01

    Flurbiprofen–antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (–COOH) was temporarily masked by esterification with phenolic –OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (Pflurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer’s yeast-induced pyrexia model, and significant (Pflurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug. PMID:27555750

  14. Flurbiprofen-antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling.

    Science.gov (United States)

    Ashraf, Zaman; Alamgeer; Kanwal, Munazza; Hassan, Mubashir; Abdullah, Sahar; Waheed, Mamuna; Ahsan, Haseeb; Kim, Song Ja

    2016-01-01

    Flurbiprofen-antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (-COOH) was temporarily masked by esterification with phenolic -OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (Pflurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer's yeast-induced pyrexia model, and significant (Pflurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug.

  15. A prodrug approach involving in situ depot formation to achieve localized and sustained action of diclofenac after joint injection.

    Science.gov (United States)

    Thing, Mette; Ågårdh, Li; Larsen, Susan; Rasmussen, Rune; Pallesen, Jakob; Mertz, Nina; Kristensen, Jesper; Hansen, Martin; Østergaard, Jesper; Larsen, Claus Selch

    2014-12-01

    Long-acting nonsteroidal anti-inflammatory drug formulations for intra-articular injection might be effective in the management of joint pain and inflammation associated sports injuries and osteoarthritis. In this study, a prodrug-based delivery system was evaluated. The synthesized diclofenac ester prodrug, a weak base (pKa 7.52), has relatively high solubility at low pH (6.5 mg mL(-1) at pH 4) and much lower solubility at physiological pH (4.5 μg mL(-1) at pH 7.4) at 37°C. In biological media including 80% (v/v) human synovial fluid (SF), the prodrug was cleaved to diclofenac mediated by esterases. In situ precipitation of the prodrug was observed upon addition of a concentrated slightly acidic prodrug solution to phosphate buffer or SF at pH 7.4. The degree of supersaturation accompanying the precipitation process was more pronounced in SF than in phosphate buffer. In the rotating dialysis cell model, a slightly acidic prodrug solution was added to the donor cell containing 80% SF resulting in a continuous appearance of diclofenac in the acceptor phase for more than 43 h after an initial lag period of 8 h. Detectable amounts of prodrug were found in the rat joint up to 8 days after knee injection of the acidic prodrug solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. Distribution and pharmacokinetics of the prodrug daunorubicin-GA3 in nude mice bearing human ovarian cancer xenografts

    NARCIS (Netherlands)

    Houba, PHJ; Boven, E; van der Meulen-Muileman, IH; Leenders, RGG; Scheeren, JW; Pinedo, HM; Haisma, HJ

    1999-01-01

    N-[4-daunorubicin-N-carbonyl (oxymethyl)phenyl] O-beta-glucuronyl carbamate (DNR-GA3) is a glucuronide prodrug of daunorubicin (DNR) which induced a better tumor growth delay than DNR when studied at equitoxic doses in three human ovarian cancer xenografts. These results suggested that the prodrug

  17. Synthesis, In Vitro and In Vivo Evaluation of the N-ethoxycarbonylmorpholine Ester of Diclofenac as a Prodrug

    Directory of Open Access Journals (Sweden)

    Jamal A. Jilani

    2014-04-01

    Full Text Available The N-ethoxycarbonylmorpholine moiety was evaluated as a novel prodrug moiety for carboxylic acid containing drugs represented by diclofenac (1. Compound 2, the N-ethoxycarbonylmorpholine ester of diclofenac was synthesized and evaluated as a potential prodrug. The stability of the synthesized prodrug was evaluated in solutions of pH 1 and 7.4, and in plasma. The ester’s half lives were found to be 8 h, 47 h and 21 min in pH 1, pH 7.4 and plasma, respectively. Equimolar doses of diclofenac sodium and its synthesized prodrug were administered orally to a group of rabbits in a crossover study to evaluate their pharmacokinetic parameters. The prodrug 2 shows a similar rate and extent of absorption as the parent drug (1. The ulcerogenicity of the prepared prodrug was evaluated and compared with the parent drug. The prodrug showed less ulcerogenicity as detected by fewer number and smaller size of ulcers. In conclusion, the newly synthesized N-ethoxycarbonylmorpholine ester of diclofenac prodrug showed appropriate stability properties at different pHs, similar pharmacokinetic profile, and much less ulcerogenecity at the GIT compared to the parent drug diclofenac.

  18. Click polymerization for the synthesis of reduction-responsive polymeric prodrug

    Science.gov (United States)

    Zhang, Xiaojin; Wang, Hongquan; Dai, Yu

    2018-05-01

    Click polymerization is a powerful polymerization technique for the construction of new macromolecules with well-defined structures and multifaceted functionalities. Here, we synthesize reduction-responsive polymeric prodrug PEG- b-(PSS- g-MTX)- b-PEG containing disulfide bonds and pendant methotrexate (MTX) via two-step click polymerization followed by conjugating MTX to pendant hydroxyl. MTX content in polymeric prodrug is 13.5%. Polymeric prodrug is able to form polymeric micelles by self-assembly in aqueous solution. Polymeric micelles are spherical nanoparticles with tens of nanometers in size. Of note, polymeric micelles are reduction-responsive due to disulfide bonds in the backbone of PEG- b-(PSS- g-MTX)- b-PEG and could release pendant drugs in the presence of the reducing agents such as dl-dithiothreitol (DTT).

  19. N,N'-dihydroxyamidines: a new prodrug principle to improve the oral bioavailability of amidines.

    Science.gov (United States)

    Reeh, Christiane; Wundt, Judith; Clement, Bernd

    2007-12-27

    N, N'-dihydroxybenzamdine represents a model compound for a new prodrug principle to improve the oral bioavailability of drugs containing amidine functions. The activation of the prodrug could be demonstrated in vitro by porcine and human subcellular enzyme fractions, the mitochondrial benzamidoxime reducing system, and porcine hepatocytes. In vivo, the bioavailability of benzamidine after oral application of N, N'-dihydroxybenzamidine was about 91% and exceeded that of benzamidine after oral application of benzamidoxime, being about 74% (Liu, L.; Ling, Y.; Havel, C.; Bashnick, L.; Young, W.; Rai, R.; Vijaykumar, D.; Riggs, J. R.; Ton, T.; Shaghafi, M.; Graupe, D.; Mordenti, J.; Sukbuntherng, J. Species comparison of in vitro and in vivo conversion of five N-hydroxyamidine prodrugs of fVIIA inhibitors to their corresponding active amidines. Presented at the 13th North America ISSX Meeting, Maui, HI, 2005).

  20. Lipid conjugated prodrugs for enzyme-triggered liposomal drug delivery to tumors

    DEFF Research Database (Denmark)

    Clausen, Mads Hartvig

    2011-01-01

    For some time we have been developing novel enzyme-triggered prodrugs for drug delivery targeting cancer. The liposomal prodrugs take advantage of the EPR effect to localize to tumors and of the local over-expression of secretory phospholipase A2 in tumors. Compared to conventional liposomal drug...... delivery systems, our prodrug-lipid conjugates have two main advantages: 1) the drugs are covalently linked to the lipids and thus leakage is circumvented and 2) the lipophilic bilayer of the formulated liposomes effectively shields the drugs from the aqueous environment in vivo. Consequently, the strategy...... targeting nuclear receptors and structural proteins. The presentation will highlight various strategies and recent progress towards improved systems, including chemical synthesis, enzyme activity and cytotoxicity....

  1. N-(Pivaloyloxy)alkoxy-carbonyl Prodrugs of the Glutamine Antagonist 6-Diazo-5-oxo-l-norleucine (DON) as a Potential Treatment for HIV Associated Neurocognitive Disorders.

    Science.gov (United States)

    Nedelcovych, Michael T; Tenora, Lukáš; Kim, Boe-Hyun; Kelschenbach, Jennifer; Chao, Wei; Hadas, Eran; Jančařík, Andrej; Prchalová, Eva; Zimmermann, Sarah C; Dash, Ranjeet P; Gadiano, Alexandra J; Garrett, Caroline; Furtmüller, Georg; Oh, Byoungchol; Brandacher, Gerald; Alt, Jesse; Majer, Pavel; Volsky, David J; Rais, Rana; Slusher, Barbara S

    2017-08-24

    Aberrant excitatory neurotransmission associated with overproduction of glutamate has been implicated in the development of HIV-associated neurocognitive disorders (HAND). The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON, 14) attenuates glutamate synthesis in HIV-infected microglia/macrophages, offering therapeutic potential for HAND. We show that 14 prevents manifestation of spatial memory deficits in chimeric EcoHIV-infected mice, a model of HAND. 14 is not clinically available, however, because its development was hampered by peripheral toxicities. We describe the synthesis of several substituted N-(pivaloyloxy)alkoxy-carbonyl prodrugs of 14 designed to circulate inert in plasma and be taken up and biotransformed to 14 in the brain. The lead prodrug, isopropyl 6-diazo-5-oxo-2-(((phenyl(pivaloyloxy)methoxy)carbonyl)amino)hexanoate (13d), was stable in swine and human plasma but liberated 14 in swine brain homogenate. When dosed systemically in swine, 13d provided a 15-fold enhanced CSF-to-plasma ratio and a 9-fold enhanced brain-to-plasma ratio relative to 14, opening a possible clinical path for the treatment of HAND.

  2. TRASTUZUMAB EMTANSINE Tumor-Activated Prodrug (TAP) Immunoconjugate Oncolytic

    DEFF Research Database (Denmark)

    Kümler, Iben; Nielsen, Dorte Lisbet; Mortensen, C Ehlers

    2011-01-01

    Trastuzumub emtansine (T-DM1) is a novel antibody-drug conjugate. The conjugate is comprised of the antibody trastuzurnab, which is directed against the receptor tyrosine-protein kinase erbB-2 (HERZ), a derivative of the cytostatic agent maytansinoid DM1(mertansine), and a linker that covalently ...

  3. Activity of the hypoxia-activated prodrug, TH-302, in preclinical human acute myeloid leukemia models.

    Science.gov (United States)

    Portwood, Scott; Lal, Deepika; Hsu, Yung-Chun; Vargas, Rodrigo; Johnson, Megan K; Wetzler, Meir; Hart, Charles P; Wang, Eunice S

    2013-12-01

    Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm. Recent evidence has shown the bone marrow microenvironment in patients with AML to be intrinsically hypoxic. Adaptive cellular responses by leukemia cells to survive under low oxygenation also confer chemoresistance. We therefore asked whether therapeutic exploitation of marrow hypoxia via the hypoxia-activated nitrogen mustard prodrug, TH-302, could effectively inhibit AML growth. We assessed the effects of hypoxia and TH-302 on human AML cells, primary samples, and systemic xenograft models. We observed that human AML cells and primary AML colonies cultured under chronic hypoxia (1% O2, 72 hours) exhibited reduced sensitivity to cytarabine-induced apoptosis as compared with normoxic controls. TH-302 treatment resulted in dose- and hypoxia-dependent apoptosis and cell death in diverse AML cells. TH-302 preferentially decreased proliferation, reduced HIF-1α expression, induced cell-cycle arrest, and enhanced double-stranded DNA breaks in hypoxic AML cells. Hypoxia-induced reactive oxygen species by AML cells were also diminished. In systemic human AML xenografts (HEL, HL60), TH-302 [50 mg/kg intraperitoneally (i.p.) 5 times per week] inhibited disease progression and prolonged overall survival. TH-302 treatment reduced the number of hypoxic cells within leukemic bone marrows and was not associated with hematologic toxicities in nonleukemic or leukemic mice. Later initiation of TH-302 treatment in advanced AML disease was as effective as earlier TH-302 treatment in xenograft models. Our results establish the preclinical activity of TH-302 in AML and provide the rationale for further clinical studies of this and other hypoxia-activated agents for leukemia therapy. ©2013 AACR.

  4. Manipulation of P450 gene expression in tumours; a novel approach for targeted activation of bioreductive prodrugs

    International Nuclear Information System (INIS)

    Robson, T.; Yakkundi, A.; McCarthy, H.; McErlane, V.; Hughes, C.M.; Hirst, D.G.; McKeown, S.R.; Patterson, L.H.

    2003-01-01

    We are developing a gene-directed enzyme prodrug therapy (GDEPT) strategy to enhance the metabolism of a novel bioreductive drug, AQ4N. Bioreductive drugs are metabolically activated in the hypoxic cell environment allowing effective targeting of hypoxic radioresistant tumour regions. We aim to achieve additional layers of selectivity by using an X-ray inducible promoter linked to our therapeutic gene (cytochrome P450s). This strategy would enhance metabolism of the drug only within the radiation field. Furthermore, normal tissue would be unaffected as the bioreductive drug is only activated in hypoxic conditions. We have identified several human cytochrome P450s which are important for AQ4N prodrug activation, these include CYP3A4, 1A1 and 2B6. RIF1 murine tumour cells transfected with cDNA from any one of these CYPs displayed increased DNA damage and clonogenic cell kill following treatment with AQ4N under hypoxia compared to controls. We are presently testing the ability of these transfectants to enhance anti-tumour effectiveness of AQ4N in combination with radiation in vivo. We have shown that a single CYP3A4 injection using a simple non-optimized approach can increase metabolism of AQ4N and when used in combination with radiation 3 out of 4 tumours are locally controlled for > 60 days (McCarthy et al., 2002). This result is remarkable considering the large enhancement of the radiation effect achieved by adding AQ4N alone. This implies that the bioreduction of AQ4N by CYPs in this tumour system is sub-optimal and this strategy could therefore be very promising for clinical use where CYP levels are known to be variable. We are now exploring the CYP/AQ4N GDEPT strategy in combination with cyclophosphamide, which is also metabolised by CYPs and aim to link these CYPs to the radiation and hypoxia inducible WAF1 promoter for selective activation in vivo

  5. Click and Release: A Chemical Strategy toward Developing Gasotransmitter Prodrugs by Using an Intramolecular Diels-Alder Reaction.

    Science.gov (United States)

    Ji, Xingyue; Zhou, Cheng; Ji, Kaili; Aghoghovbia, Robert E; Pan, Zhixiang; Chittavong, Vayou; Ke, Bowen; Wang, Binghe

    2016-12-19

    Prodrug strategies have been proven to be a very effective way of addressing delivery problems. Much of the chemistry in prodrug development relies on the ability to mask an appropriate functional group, which can be removed under appropriate conditions. However, developing organic prodrugs of gasotransmitters represent unique challenges. This is especially true with carbon monoxide, which does not have an easy "handle" for bioreversible derivatization. By taking advantage of an intramolecular Diels-Alder reaction, we have developed a prodrug strategy for preparations of organic CO prodrugs that are stable during synthesis and storage, and yet readily release CO with tunable release rates under near physiological conditions. The effectiveness of the CO prodrug system in delivering a sufficient quantity of CO for possible therapeutic applications has been studied using a cell culture anti-inflammatory assay and a colitis animal model. These studies fully demonstrate the proof of concept, and lay a strong foundation for further medicinal chemistry work in developing organic CO prodrugs. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Structural coupling of SH2-kinase domains links Fes and Abl substrate recognition and kinase activation.

    Science.gov (United States)

    Filippakopoulos, Panagis; Kofler, Michael; Hantschel, Oliver; Gish, Gerald D; Grebien, Florian; Salah, Eidarus; Neudecker, Philipp; Kay, Lewis E; Turk, Benjamin E; Superti-Furga, Giulio; Pawson, Tony; Knapp, Stefan

    2008-09-05

    The SH2 domain of cytoplasmic tyrosine kinases can enhance catalytic activity and substrate recognition, but the molecular mechanisms by which this is achieved are poorly understood. We have solved the structure of the prototypic SH2-kinase unit of the human Fes tyrosine kinase, which appears specialized for positive signaling. In its active conformation, the SH2 domain tightly interacts with the kinase N-terminal lobe and positions the kinase alphaC helix in an active configuration through essential packing and electrostatic interactions. This interaction is stabilized by ligand binding to the SH2 domain. Our data indicate that Fes kinase activation is closely coupled to substrate recognition through cooperative SH2-kinase-substrate interactions. Similarly, we find that the SH2 domain of the active Abl kinase stimulates catalytic activity and substrate phosphorylation through a distinct SH2-kinase interface. Thus, the SH2 and catalytic domains of active Fes and Abl pro-oncogenic kinases form integrated structures essential for effective tyrosine kinase signaling.

  7. Cationic polymeric gene delivery of beta-glucuronidase for doxorubicin prodrug therapy

    NARCIS (Netherlands)

    Fonseca, MJ; Storm, G; Hennink, WE; Gerritsen, WR; Haisma, HJ

    1999-01-01

    Background An approach to improve current chemotherapy is the selective transduction of tumor cells with suicide genes to sensitize these cells to prodrugs of cytostatic agents; Methods In this study, gene transfer was accomplished with the cationic polymer poly(2-(dimethylamino)ethyl methacrylate)

  8. Selective transfer of a lipophilic prodrug of 5-fluorodeoxyuridine from immunoliposomes to colon cancer cells

    NARCIS (Netherlands)

    Koning, GA; Morselt, HWM; Donga, J; Gorter, A; Allen, TM; Zalipsky, S; Kamps, JAAM; Scherphof, GL

    1999-01-01

    A monoclonal antibody against the rat colon carcinoma CC531 was covalently coupled to liposomes containing a dipalmitoylated derivative of the anticancer drug FUdR as a prodrug in their bilayers. We investigated the in vitro interaction of these liposomes with CC531 target cells and the mechanism by

  9. Prodrug and nanomedicine approaches for the delivery of the camptothecin analogue SN38.

    Science.gov (United States)

    Bala, Vaskor; Rao, Shasha; Boyd, Ben J; Prestidge, Clive A

    2013-11-28

    SN38 (7-ethyl-10-hydroxy camptothecin) is a prominent and efficacious anticancer agent. It is poorly soluble in both water and pharmaceutically approved solvents; therefore, the direct formulation of SN38 in solution form is limited. Currently, the water soluble prodrug of SN38, irinotecan (CPT-11), is formulated as a low pH solution and is approved for chemotherapy. However, CPT-11, along with most other water-soluble prodrugs shows unpredictable inter-patient conversion to SN38 in vivo, instability in the physiological environment and variable dose-related toxicities. More recently, macromolecular prodrugs (i.e. EZN-2208, IMMU-130) and nanomedicine formulations (i.e. nanoemulsions, polymeric micelles, lipid nanocapsule/nanoparticle, and liposomes) of SN38 have been investigated for improved delivery to cancer cells and tissues. Specifically, these carriers can take advantage of the EPR effect to direct drug preferentially to tumour tissues, thereby substantially improving efficacy and minimising side effects. Furthermore, oral delivery has been shown to be possible in preclinical results using nanomedicine formulations (i.e. dendrimers, lipid nanocapsules, polymeric micelles). This review summarizes the recent advances for the delivery of SN38 with a focus on macromolecular prodrugs and nanomedicines. © 2013 Elsevier B.V. All rights reserved.

  10. Prodrugs available on the Brazilian pharmaceutical market and their corresponding bioactivation pathways

    Directory of Open Access Journals (Sweden)

    Roberto Parise Filho

    2010-09-01

    Full Text Available The aim of this paper was to emphasize the importance of prodrug design to therapy, by examining examples available on the Brazilian pharmaceutical market. The principles of prodrug design are briefly discussed herein. Examples of prodrugs from many important therapeutic classes are shown and their advantages relative to the drugs they are derived from are also discussed. Considering the importance of these therapeutic classes, from both therapy and economic standpoints, prodrug design is a very valuable aspect in the research of new drugs and for the pharmaceutical industry as a whole.O objetivo do trabalho foi ressaltar a importância do planejamento de pró-fármacos para a terapia, por meio de exemplos disponíveis no mercado farmacêutico brasileiro. Os princípios da latenciação são sucintamente discutidos. Apresentam-se exemplos de pró-fármacos de muitas classes terapêuticas importantes e as vantagens relativas aos fármacos dos quais derivam são, também, discutidas. Considerando-se a importância dessas classes terapêuticas, tanto do aspecto terapêutico quanto do econômico, o planejamento de pró-fármacos representa aspecto de grande valor na busca de novos fármacos e na indústria farmacêutica como um todo.

  11. Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy.

    Science.gov (United States)

    Mistry, Ishna N; Thomas, Matthew; Calder, Ewen D D; Conway, Stuart J; Hammond, Ester M

    2017-08-01

    With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiation therapy and bioreductive drugs presents an attractive opportunity for synergistic effects, because the HAP targets the radiation-resistant hypoxic cells. Hypoxia-activated prodrugs have typically been precursors of DNA-damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiation therapy and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Lysosome-Targeting Amplifiers of Reactive Oxygen Species as Anticancer Prodrugs

    Czech Academy of Sciences Publication Activity Database

    Daum, S.; Reshetnikov, M.S.V.; Šíša, Miroslav; Dumych, T.; Lootsik, M. D.; Bilyy, R.; Bila, E.; Janko, C.; Alexiou, C.; Herrmann, M.; Sellner, L.; Mokhir, A.

    2017-01-01

    Roč. 56, č. 49 (2017), s. 15545-15549 ISSN 1433-7851 Institutional support: RVO:61389030 Keywords : aminoferrocene * cancer * lysosomes * prodrugs * reactive oxygen species Subject RIV: ED - Physiology OBOR OECD: Organic chemistry Impact factor: 11.994, year: 2016

  13. Chemotherapeutic potential of diazeniumdiolate-based aspirin prodrugs in breast cancer.

    Science.gov (United States)

    Basudhar, Debashree; Cheng, Robert C; Bharadwaj, Gaurav; Ridnour, Lisa A; Wink, David A; Miranda, Katrina M

    2015-06-01

    Diazeniumdiolate-based aspirin prodrugs have previously been shown to retain the anti-inflammatory properties of aspirin while protecting against the common side effect of stomach ulceration. Initial analysis of two new prodrugs of aspirin that also release either nitroxyl (HNO) or nitric oxide (NO) demonstrated increased cytotoxicity toward human lung carcinoma cells compared to either aspirin or the parent nitrogen oxide donor. In addition, cytotoxicity was significantly lower in endothelial cells, suggesting cancer-specific sensitivity. To assess the chemotherapeutic potential of these new prodrugs in treatment of breast cancer, we studied their effect both in cultured cells and in a nude mouse model. Both prodrugs reduced growth of breast adenocarcinoma cells more effectively than the parent compounds while not being appreciably cytotoxic in a related nontumorigenic cell line (MCF-10A). The HNO donor also was more cytotoxic than the related NO donor. The basis for the observed specificity was investigated in terms of impact on metabolism, DNA damage and repair, apoptosis, angiogenesis and metastasis. The results suggest a significant pharmacological potential for treatment of breast cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Improved Synthesis of N-Benzylaminoferrocene-Based Prodrugs and Evaluation of Their Toxicity and Antileukemic Activity

    NARCIS (Netherlands)

    Daum, Steffen; Chekhun, Vasiliy F; Todor, Igor N; Lukianova, Natalia Yu; Shvets, Yulia V; Sellner, Leopold; Putzker, Kerstin; Lewis, Joe; Zenz, Thorsten; de Graaf, Inge A M; Groothuis, Geny M M; Casini, Angela; Zozulia, Oleksii; Hampel, Frank; Mokhir, Andriy

    2015-01-01

    We report on an improved method of synthesis of N-benzylaminoferrocene-based prodrugs and demonstrate its applicability by preparing nine new aminoferrocenes. Their effect on the viability of selected cancer cells having different p53 status was studied. The obtained data are in agreement with the

  15. Stepwise-activable multifunctional peptide-guided prodrug micelles for cancerous cells intracellular drug release

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing, E-mail: zhangjing@zjut.edu.cn; Li, Mengfei [Zhejiang University of Technology, College of Materials Science and Engineering (China); Yuan, Zhefan [Zhejiang University, Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemical and Biological Engineering (China); Wu, Dan; Chen, Jia-da; Feng, Jie, E-mail: fengjie@zjut.edu.cn [Zhejiang University of Technology, College of Materials Science and Engineering (China)

    2016-10-15

    A novel type of stepwise-activable multifunctional peptide-guided prodrug micelles (MPPM) was fabricated for cancerous cells intracellular drug release. Deca-lysine sequence (K{sub 10}), a type of cell-penetrating peptide, was synthesized and terminated with azido-glycine. Then a new kind of molecule, alkyne modified doxorubicin (DOX) connecting through disulfide bond (DOX-SS-alkyne), was synthesized. After coupling via Cu-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry reaction, reduction-sensitive peptide-guided prodrug was obtained. Due to the amphiphilic property of the prodrug, it can assemble to form micelles. To prevent the nanocarriers from unspecific cellular uptake, the prodrug micelles were subsequently modified with 2,3-dimethyl maleic anhydride to obtain MPPM with a negatively charged outer shell. In vitro studies showed that MPPM could be shielded from cells under psychological environment. However, when arriving at mild acidic tumor site, the cell-penetrating capacity of MPPM would be activated by charge reversal of the micelles via hydrolysis of acid-labile β-carboxylic amides and regeneration of K{sub 10}, which enabled efficient internalization of MPPM by tumor cells as well as following glutathione- and protease-induced drug release inside the cancerous cells. Furthermore, since the guide peptide sequences can be accurately designed and synthesized, it can be easily changed for various functions, such as targeting peptide, apoptotic peptide, even aptamers, only need to be terminated with azido-glycine. This method can be used as a template for reduction-sensitive peptide-guided prodrug for cancer therapy.Graphical abstractA novel type of stepwise-activable multifunctional peptide-guided prodrug micelles (MPPM) was fabricated for selective drug delivery in cancerous cells. MPPM could be shielded from cells under psychological environment. However, when arriving at mild acidic tumor site, the cell-penetrating capacity of MPPM would

  16. Can primary reducing radicals be recruited for prodrug activation in tissue?

    International Nuclear Information System (INIS)

    Kriste, A.G.; Ferry, D.M.; Anderson, R.F.; Wilson, W.R.

    2003-01-01

    We have previously demonstrated that the nitroarylmethyl quaternary ammonium (NMQ) prodrugs of mechlorethamine (HN2) can be activated under anoxia by ionizing radiation (Kriste et al. Radiation Research, 158, 753 - 762, 2002). The HN2 released by these model compounds, however, is insufficiently potent for the prodrugs to be therapeutically useful. To address this concern, NMQ trigger units (4-nitroimidazole, 2-nitropyrrole and 3-nitrothiophene; all demonstrate one-electron release of HN2) were tethered to the DNA intercalator, AMAC (IC 50 values of 1.3 to 66 nM against human and rodent tumour cells). We now report whether AMAC can be radiolytically released from NMQ-AMAC prodrugs in a hypoxic tissue-like environment. Initially radiolysis was investigated in anoxic 0.1 M Formate buffer. Here, the G value for AMAC release was 0.33 ± 0.02μmol/J. In anoxic human plasma, radiolytic release was half as efficient (G(AMAC)= 0.18 ± 0.03μmol/J). To investigate AMAC release in tissue, V79-171b rodent tumour cells were seeded onto Millicell-CM cell culture inserts and grown to 10 - 20 cell diameters. These multicellular layers (MCLs) were equilibrated with prodrug (1μM, 4 hours), and transferred to a gassing chamber (95% nitrogen or oxygen, 2 minutes). MCLs were irradiated (high dose linear accelerator, 0 - 800 Gy, 35 Gy/pulse) and lysed. HPLC analysis indicated that each prodrug was taken up intracellularly to ca. 50 μM. Furthermore, AMAC release was linear with radiation dose and was inhibited under oxia. In this tissue, G values spanned a range from 9.0 to 15 nmol/J. These low values, ca. 5 % of the plasma value, are interpreted as reflecting unfavourable prodrug localization into acidic intracellular endosomes, with no clear E(1) dependance. Whether radiolytic reduction occurs via e aq - or H . abstraction to generate carbon-centred radicals is unknown. MCL studies with NMQ prodrugs that release alternate amine containing cytotoxins are currently in progress

  17. Targeted theranostic platinum(IV) prodrug with a built-in aggregation-induced emission light-up apoptosis sensor for noninvasive early evaluation of its therapeutic responses in situ.

    Science.gov (United States)

    Yuan, Youyong; Kwok, Ryan T K; Tang, Ben Zhong; Liu, Bin

    2014-02-12

    Targeted drug delivery to tumor cells with minimized side effects and real-time in situ monitoring of drug efficacy is highly desirable for personalized medicine. In this work, we report the synthesis and biological evaluation of a chemotherapeutic Pt(IV) prodrug whose two axial positions are functionalized with a cyclic arginine-glycine-aspartic acid (cRGD) tripeptide for targeting integrin αvβ3 overexpressed cancer cells and an apoptosis sensor which is composed of tetraphenylsilole (TPS) fluorophore with aggregation-induced emission (AIE) characteristics and a caspase-3 enzyme specific Asp-Glu-Val-Asp (DEVD) peptide. The targeted Pt(IV) prodrug can selectively bind to αvβ3 integrin overexpressed cancer cells to facilitate cellular uptake. In addition, the Pt(IV) prodrug can be reduced to active Pt(II) drug in cells and release the apoptosis sensor TPS-DEVD simultaneously. The reduced Pt(II) drug can induce the cell apoptosis and activate caspase-3 enzyme to cleave the DEVD peptide sequence. Due to free rotation of the phenylene rings, TPS-DEVD is nonemissive in aqueous media. The specific cleavage of DEVD by caspase-3 generates the hydrophobic TPS residue, which tends to aggregate, resulting in restriction of intramolecular rotations of the phenyl rings and ultimately leading to fluorescence enhancement. Such noninvasive and real-time imaging of drug-induced apoptosis in situ can be used as an indicator for early evaluation of the therapeutic responses of a specific anticancer drug.

  18. Flurbiprofen–antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling

    Directory of Open Access Journals (Sweden)

    Ashraf Z

    2016-07-01

    Full Text Available Zaman Ashraf,1,2 Alamgeer,3 Munazza Kanwal,1 Mubashir Hassan,2 Sahar Abdullah,3 Mamuna Waheed,3 Haseeb Ahsan,3 Song Ja Kim2 1Department of Chemistry, Allama Iqbal Open University, Islamabad, Pakistan; 2Department of Biological Sciences, College of Natural Sciences, Kongju National University, Gongju, Republic of Korea; 3Department of Pharmacology, Faculty of Pharmacy, University of Sargodha, Sargodha, Pakistan Abstract: Flurbiprofen–antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (–COOH was temporarily masked by esterification with phenolic –OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, ­suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (P<0.001 reduced the inflammation against carrageenan and egg albumin-induced paw edema at 4 hours of study. The reduction in the size of the inflamed paw showed that most of the compounds inhibited the later phase of inflammation. The prodrug 2-oxo-2H-chromen-7-yl-2-(2-fluorobiphenyl-4-ylpropanoate (4b showed significant reduction in paw licking with percentage inhibition of 58%. It also exhibited higher analgesic activity, reducing the number of writhes with a percentage of 75%, whereas flurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer’s yeast-induced pyrexia model, and significant (P<0.001 reduction in rectal temperature was shown by all

  19. Synthesis, In Vitro and In Vivo Evaluation of the N-ethoxycarbonylmorpholine Ester of Diclofenac as a Prodrug

    OpenAIRE

    Jilani, Jamal; Idkaidek, Nasir; Alzoubi, Karem

    2014-01-01

    The N-ethoxycarbonylmorpholine moiety was evaluated as a novel prodrug moiety for carboxylic acid containing drugs represented by diclofenac (1). Compound 2, the N-ethoxycarbonylmorpholine ester of diclofenac was synthesized and evaluated as a potential prodrug. The stability of the synthesized prodrug was evaluated in solutions of pH 1 and 7.4, and in plasma. The ester’s half lives were found to be 8 h, 47 h and 21 min in pH 1, pH 7.4 and plasma, respectively. Equimolar doses of diclofenac...

  20. Synthesis and Evaluation of Hydrogen Peroxide Sensitive Prodrugs of Methotrexate and Aminopterin for the Treatment of Rheumatoid Arthritis

    DEFF Research Database (Denmark)

    Peiró Cadahía, Jorge; Bondebjerg, Jon; Hansen, Christian A.

    2018-01-01

    A series of novel hydrogen peroxide sensitive prodrugs of methotrexate (MTX) and aminopterin (AMT) were synthesized and evaluated for therapeutic efficacy in mice with collagen induced arthritis (CIA) as a model of chronic rheumatoid arthritis (RA). The prodrug strategy selected is based on ROS...... assays. Selected candidates showed moderate to good solubility, high chemical and enzymatic stability, and therapeutic efficacy comparable to the parent drugs in the CIA model. Importantly, the prodrugs displayed the expected safer toxicity profile and increased therapeutic window compared to MTX and AMT...

  1. Pharmacokinetics of Curcumin Diethyl Disuccinate, a Prodrug of Curcumin, in Wistar Rats.

    Science.gov (United States)

    Bangphumi, Kunan; Kittiviriyakul, Chuleeporn; Towiwat, Pasarapa; Rojsitthisak, Pornchai; Khemawoot, Phisit

    2016-12-01

    Curcumin is the major bioactive component of turmeric, but has poor oral bioavailability that limits its clinical applications. To improve the in vitro solubility and alkaline stability, we developed a prodrug of curcumin by succinylation to obtain curcumin diethyl disuccinate, with the goal of improving the oral bioavailability of curcumin. The in vivo pharmacokinetic profile of curcumin diethyl disuccinate was compared with that of curcumin in male Wistar rats. Doses of curcumin 20 mg/kg intravenous or 40 mg/kg oral were used as standard regimens for comparison with the prodrug at equivalent doses in healthy adult rats. Blood, tissues, urine, and faeces were collected from time zero to 48 h after dosing to determine the prodrug level, curcumin level and a major metabolite by liquid chromatography-tandem spectrometry. The absolute oral bioavailability of curcumin diethyl disuccinate was not significantly improved compared with curcumin, with both compounds having oral bioavailability of curcumin less than 1 %. The major metabolic pathway of the prodrug was rapid hydrolysis to obtain curcumin, followed by glucuronidation. Interestingly, curcumin diethyl disuccinate gave superior tissue distribution with higher tissue to plasma ratio of curcumin and curcumin glucuronide in several organs after intravenous dosing at 1 and 4 h. The primary elimination route of curcumin glucuronide occurred via biliary and faecal excretion, with evidence of an entry into the enterohepatic circulation. Curcumin diethyl disuccinate did not significantly improve the oral bioavailability of curcumin due to first pass metabolism in the gastrointestinal tract. Further studies on reduction of first pass metabolism are required to optimise delivery of curcumin using a prodrug approach.

  2. Design of optimized hypoxia-activated prodrugs using pharmacokinetic/pharmacodynamic modeling

    Directory of Open Access Journals (Sweden)

    Annika Bettina Foehrenbacher

    2013-12-01

    Full Text Available Hypoxia contributes to resistance of tumors to some cytotoxic drugs and to radiotherapy, but can in principle be exploited with hypoxia-activated prodrugs (HAP. HAP in clinical development fall into two broad groups. Class I HAP (like the benzotriazine N-oxides tirapazamine and SN30000, are activated under relatively mild hypoxia. In contrast, Class II HAP (such as the nitro compounds PR-104A or TH-302 are maximally activated only under extreme hypoxia, but their active metabolites (effectors diffuse to cells at intermediate O2 and thus also eliminate moderately hypoxic cells. Here, we use a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD model to compare these two strategies and to identify the features required in an optimal Class II HAP. The model uses a Green’s function approach to calculate spatial and longitudinal gradients of O2, prodrug and effector concentrations, and resulting killing in a digitized 3D tumor microregion to estimate activity as monotherapy and in combination with radiotherapy. An analogous model for a normal tissue with mild hypoxia and short intervesssel distances (based on a cremaster muscle microvessel network was used to estimate tumor selectivity of cell killing. This showed that Class II HAP offer advantages over Class I including higher tumor selectivity and greater freedom to vary prodrug diffusibility and rate of metabolic activation. The model suggests that the largest gains in class II HAP antitumor activity could be realized by optimizing effector stability and prodrug activation rates. We also use the model to show that diffusion of effector into blood vessels is unlikely to materially increase systemic exposure for realistic tumor burdens and effector clearances. However, we show that the tumor selectivity achievable by hypoxia-dependent prodrug activation alone is limited if dose-limiting normal tissues are even mildly hypoxic

  3. Comparative plasma disposition kinetics of albendazole and its new benzimidazol prodrug in dog.

    Science.gov (United States)

    Khalil, Z; El Karbane, M; Faouzi, M E A; Ansar, M; Azougagh, M; El Harti, J; Taoufik, J

    2016-01-01

    The comparative pharmacokinetic behavior of albendazole (ABZ) and its new benzimidazol prodrug [1-tert-butyloxycarbonyl-5-propylthio-1-H-benzimidazol-2ylcarbamate of methyl] (ABZBoc), following their oral administration (10mg/kg) to healthy dogs was explored. Blood samples were obtained serially over a 24h period after treatment, then the plasma was analyzed by high-performance liquid chromatography (HPLC) to search the albendazole metabolites (ABZSO and ABZSO2). However, the albendazole parent drug was not detectable at any time after both treatments (ABZ and ABZBoc). By albendazole metabolites (ABZSO and ABZSO2) were the analytes recovered in the plasma after oral administration of ABZ and ABZBoc. Furthermore, some amounts of ABZBoc were also available in the plasma samples treated with this new produg. The plasma profile of each analyte followed a similar pattern after both treatments, the active metabolite (ABZSO) was the major analyte recovered in plasma (between 1 and 24h post-treatment). The pharmacokinetic parameters of both groups were calculated (Cmax, Tmax, t1/2, AUC0-›∞), and analyzed using the Student's t-test, Palbendazole metabolites (ABZSO, ABZSO2) between the group treated with albendazole (group A) and that treated with ABZBoc prodrug (group B). Hence, the levels of the various pharmacokinetics parameters were low in the group treated with prodrug, as well they did not reach equivalent concentrations to that of albendazole. These differences between albendazole and its new prodrug may be explained by the fact that ABZBoc prodrug was not effectively reduced in the intestine of dogs. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

  4. Allosteric inhibition enhances the efficacy of ABL kinase inhibitors to target unmutated BCR-ABL and BCR-ABL-T315I

    Directory of Open Access Journals (Sweden)

    Mian Afsar

    2012-09-01

    Full Text Available Abstract Background Chronic myelogenous leukemia (CML and Philadelphia chromosome-positive (Ph+ acute lymphatic leukemia (Ph + ALL are caused by the t(9;22, which fuses BCR to ABL resulting in deregulated ABL-tyrosine kinase activity. The constitutively activated BCR/ABL-kinase “escapes” the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. The ABL-kinase inhibitors (AKIs Imatinib, Nilotinib or Dasatinib, which target the ATP-binding site, are effective in Ph + leukemia. Another molecular therapy approach targeting BCR/ABL restores allosteric inhibition. Given the fact that all AKIs fail to inhibit BCR/ABL harboring the ‘gatekeeper’ mutation T315I, we investigated the effects of AKIs in combination with the allosteric inhibitor GNF2 in Ph + leukemia. Methods The efficacy of this approach on the leukemogenic potential of BCR/ABL was studied in Ba/F3 cells, primary murine bone marrow cells, and untransformed Rat-1 fibroblasts expressing BCR/ABL or BCR/ABL-T315I as well as in patient-derived long-term cultures (PDLTC from Ph + ALL-patients. Results Here, we show that GNF-2 increased the effects of AKIs on unmutated BCR/ABL. Interestingly, the combination of Dasatinib and GNF-2 overcame resistance of BCR/ABL-T315I in all models used in a synergistic manner. Conclusions Our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants using a combination of AKIs and allosteric inhibitors.

  5. The Feasibility of Enzyme Targeted Activation for Amino Acid/Dipeptide Monoester Prodrugs of Floxuridine; Cathepsin D as a Potential Targeted Enzyme

    Directory of Open Access Journals (Sweden)

    Gordon L. Amidon

    2012-03-01

    Full Text Available The improvement of therapeutic efficacy for cancer agents has been a big challenge which includes the increase of tumor selectivity and the reduction of adverse effects at non-tumor sites. In order to achieve those goals, prodrug approaches have been extensively investigated. In this report, the potential activation enzymes for 5¢-amino acid/dipeptide monoester floxuridine prodrugs in pancreatic cancer cells were selected and the feasibility of enzyme specific activation of prodrugs was evaluated. All prodrugs exhibited the range of 3.0–105.7 min of half life in Capan-2 cell homogenate with the presence and the absence of selective enzyme inhibitors. 5¢-O-L-Phenylalanyl-L-tyrosyl-floxuridine exhibited longer half life only with the presence of pepstatin A. Human cathepsin B and D selectively hydrolized 5¢-O-L-phenylalanyl-L-tyrosylfloxuridine and 5¢-O-L-phenylalanyl-L-glycylfloxuridine compared to the other tested prodrugs. The wide range of growth inhibitory effect by floxuridine prodrugs in Capan-2 cells was observed due to the different affinities of prodrug promoieties to enyzmes. In conclusion, it is feasible to design prodrugs which are activated by specific enzymes. Cathepsin D might be a good candidate as a target enzyme for prodrug activation and 5¢-O-L-phenylalanyl-L-tyrosylfloxuridine may be the best candidate among the tested floxuridine prodrugs.

  6. The feasibility of enzyme targeted activation for amino acid/dipeptide monoester prodrugs of floxuridine; cathepsin D as a potential targeted enzyme.

    Science.gov (United States)

    Tsume, Yasuhiro; Amidon, Gordon L

    2012-03-26

    The improvement of therapeutic efficacy for cancer agents has been a big challenge which includes the increase of tumor selectivity and the reduction of adverse effects at non-tumor sites. In order to achieve those goals, prodrug approaches have been extensively investigated. In this report, the potential activation enzymes for 5'-amino acid/dipeptide monoester floxuridine prodrugs in pancreatic cancer cells were selected and the feasibility of enzyme specific activation of prodrugs was evaluated. All prodrugs exhibited the range of 3.0-105.7 min of half life in Capan-2 cell homogenate with the presence and the absence of selective enzyme inhibitors. 5'-O-L-Phenylalanyl-L-tyrosyl-floxuridine exhibited longer half life only with the presence of pepstatin A. Human cathepsin B and D selectively hydrolized 5'-O-L-phenylalanyl-L-tyrosylfloxuridine and 5'-O-L-phenylalanyl-L-glycylfloxuridine compared to the other tested prodrugs. The wide range of growth inhibitory effect by floxuridine prodrugs in Capan-2 cells was observed due to the different affinities of prodrug promoieties to enzymes. In conclusion, it is feasible to design prodrugs which are activated by specific enzymes. Cathepsin D might be a good candidate as a target enzyme for prodrug activation and 5'-O-L-phenylalanyl-L-tyrosylfloxuridine may be the best candidate among the tested floxuridine prodrugs.

  7. Dual delivery systems based on polyamine analog BENSpm as prodrug and gene delivery vectors

    Science.gov (United States)

    Zhu, Yu

    -SS-BEN) capable of intracellular release of BENSpm using thiolytically sensitive dithiobenzyl carbamate linker. Similar activity on SSAT enzyme induction by Lipo-SS-BEN compared with BENSpm free drug verified the success of this prodrug design. Biodegradability of Lipo-SS-BEN contributed to decreased toxicity compared with nondegradable control LipoBEN. However, decreased enhancement of TRAIL activity was observed for Lipo-SS-BEN when compared with BENSpm, indicating that the lipid-related toxicity diminished the synergism. In addition, compared with LipoBEN and DOTAP, decreased transfection efficiency of Lipo-SS-BEN demonstrated instability of Lipo-SS-BEN in extracellular environment. In order to design a dual delivery vector with reduced vector toxicity and improved linker stability, we employed dendritic polyglycerol (PG) as a safe carrier backbone, onto which BENSpm was conjugated through carbamate linkage (PG-BEN). Polymers with norspermine (PG-Nor) shell and amine-terminated PG (PG-NH2) were synthesized as controls. The BENSpm dual vector PG-BEN demonstrated superior gene delivery function, and showed decreased toxicity compared with the control polymers. However, compared with BENSpm, which depleted all natural polyamines, PG-BEN only down-regulated intracellular putrescine levels. In addition, no free BENSpm was detected in PG-BEN treated cells. These results suggested that in order to take full advantage of BENSpm anticancer activity, alternative linker chemistry needs to be further explored. We then incorporated bis(2-hydroxyethyl) disulfide as a self-immolative linker to synthesize polymer prodrugs of BENSpm (DSS-BEN). The proposed mechanism of BENSpm release from DSS-BEN contains two steps: disulfide bond is first cleaved in the reducing intracellular space, then the intermediate further undergoes slow intramolecular cyclization to release free BENSpm. Cell line-dependent BENSpm release after DSS-BEN treatment was observed using HPLC analysis, demonstrating the

  8. Effect of alcohol on skin permeation and metabolism of an ester-type prodrug in Yucatan micropig skin.

    Science.gov (United States)

    Fujii, Makiko; Ohara, Rieko; Matsumi, Azusa; Ohura, Kayoko; Koizumi, Naoya; Imai, Teruko; Watanabe, Yoshiteru

    2017-11-15

    We studied the effect that three alcohols, ethanol (EA), propanol (PA), and isopropanol (IPA), have on the skin permeation of p-hydroxy benzoic acid methyl ester (HBM), a model ester-type prodrug. HBM was applied to Yucatan micropig skin in a saturated phosphate buffered solution with or without 10% alcohol, and HBM and related materials in receptor fluid and skin were determined with HPLC. In the absence of alcohol, p-hydroxy benzoic acid (HBA), a metabolite of HBM, permeated the skin the most. The three alcohols enhanced the penetration of HBM at almost the same extent. The addition of 10% EA or PA to the HBM solution led to trans-esterification into the ethyl ester or propyl ester of HBA, and these esters permeated skin as well as HBA and HBM did. In contrast, the addition of 10% IPA promoted very little trans-esterification. Both hydrolysis and trans-esterification in the skin S9 fraction were inhibited by BNPP, an inhibitor of carboxylesterase (CES). Western blot and native PAGE showed the abundant expression of CES in micropig skin. Both hydrolysis and trans-esterification was simultaneously catalyzed by CES during skin permeation. Our data indicate that the alcohol used in dermal drug preparations should be selected not only for its ability to enhance the solubility and permeation of the drug, but also for the effect on metabolism of the drug in the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Cinnamon Extract Enhances Glucose Uptake in 3T3-L1 Adipocytes and C2C12 Myocytes by Inducing LKB1-AMP-Activated Protein Kinase Signaling

    Science.gov (United States)

    Shen, Yan; Honma, Natsumi; Kobayashi, Katsuya; Jia, Liu Nan; Hosono, Takashi; Shindo, Kazutoshi; Ariga, Toyohiko; Seki, Taiichiro

    2014-01-01

    We previously demonstrated that cinnamon extract (CE) ameliorates type 1 diabetes induced by streptozotocin in rats through the up-regulation of glucose transporter 4 (GLUT4) translocation in both muscle and adipose tissues. This present study was aimed at clarifying the detailed mechanism(s) with which CE increases the glucose uptake in vivo and in cell culture systems using 3T3-L1 adipocytes and C2C12 myotubes in vitro. Specific inhibitors of key enzymes in insulin signaling and AMP-activated protein kinase (AMPK) signaling pathways, as well as small interference RNA, were used to examine the role of these kinases in the CE-induced glucose uptake. The results showed that CE stimulated the phosphorylation of AMPK and acetyl-CoA carboxylase. An AMPK inhibitor and LKB1 siRNA blocked the CE-induced glucose uptake. We also found for the first time that insulin suppressed AMPK activation in the adipocyte. To investigate the effect of CE on type 2 diabetes in vivo, we further performed oral glucose tolerance tests and insulin tolerance tests in type 2 diabetes model rats administered with CE. The CE improved glucose tolerance in oral glucose tolerance tests, but not insulin sensitivity in insulin tolerance test. In summary, these results indicate that CE ameliorates type 2 diabetes by inducing GLUT4 translocation via the AMPK signaling pathway. We also found insulin antagonistically regulates the activation of AMPK. PMID:24551069

  10. Tyrosine kinase inhibition increases the cell surface localization of FLT3-ITD and enhances FLT3-directed immunotherapy of acute myeloid leukemia.

    Science.gov (United States)

    Reiter, K; Polzer, H; Krupka, C; Maiser, A; Vick, B; Rothenberg-Thurley, M; Metzeler, K H; Dörfel, D; Salih, H R; Jung, G; Nößner, E; Jeremias, I; Hiddemann, W; Leonhardt, H; Spiekermann, K; Subklewe, M; Greif, P A

    2018-02-01

    The fms-related tyrosine kinase 3 (FLT3) receptor has been extensively studied over the past two decades with regard to oncogenic alterations that do not only serve as prognostic markers but also as therapeutic targets in acute myeloid leukemia (AML). Internal tandem duplications (ITDs) became of special interest in this setting as they are associated with unfavorable prognosis. Because of sequence-dependent protein conformational changes FLT3-ITD tends to autophosphorylate and displays a constitutive intracellular localization. Here, we analyzed the effect of tyrosine kinase inhibitors (TKIs) on the localization of the FLT3 receptor and its mutants. TKI treatment increased the surface expression through upregulation of FLT3 and glycosylation of FLT3-ITD and FLT3-D835Y mutants. In T cell-mediated cytotoxicity (TCMC) assays, using a bispecific FLT3 × CD3 antibody construct, the combination with TKI treatment increased TCMC in the FLT3-ITD-positive AML cell lines MOLM-13 and MV4-11, patient-derived xenograft cells and primary patient samples. Our findings provide the basis for rational combination of TKI and FLT3-directed immunotherapy with potential benefit for FLT3-ITD-positive AML patients.

  11. Discovery of Orally Available Prodrugs of the Glutamate Carboxypeptidase II (GCPII) Inhibitor 2-Phosphonomethylpentanedioic Acid (2-PMPA)

    Czech Academy of Sciences Publication Activity Database

    Majer, Pavel; Jančařík, Andrej; Krečmerová, Marcela; Tichý, Tomáš; Tenora, Lukáš; Wozniak, K.; Wu, Y.; Pommier, E.; Ferraris, D.; Rais, R.; Slusher, B. S.

    2016-01-01

    Roč. 59, č. 6 (2016), s. 2810-2819 ISSN 0022-2623 Institutional support: RVO:61388963 Keywords : glutamate carboxypeptidase II * glutamate * 2-PMPA * prodrug Subject RIV: CC - Organic Chemistry Impact factor: 6.259, year: 2016

  12. High glucose enhances cAMP level and extracellular signal-regulated kinase phosphorylation in Chinese hamster ovary cell: Usage of Br-cAMP in foreign protein β-galactosidase expression.

    Science.gov (United States)

    Lin, Hsiao-Hsien; Lee, Tsung-Yih; Liu, Ting-Wei; Tseng, Ching-Ping

    2017-07-01

    Glucose is a carbon source for Chinese hamster ovary (CHO) cell growth, while low growth rate is considered to enhance the production of recombinant proteins. The present study reveals that glucose concentrations higher than 1 g/L reduce the growth rate and substantially increase in cAMP (∼300%) at a high glucose concentration (10 g/L). High glucose also enhances the phosphorylation of extracellular signal-regulated kinase (ERK) and p27 kip by Western blot analysis. To determine whether the phosphorylation of ERK is involved in the mechanism, a cyclic-AMP dependent protein kinase A (PKA) inhibitor (H-8) or MEK (MAPKK) inhibitor (PD98059) was added to block ERK phosphorylation. We show that both the high glucose-induced ERK phosphorylation and growth rate return to baseline levels. These results suggest that the cAMP/PKA and MAP signaling pathways are involved in the abovementioned mechanism. Interestingly, the direct addition of 8-bromo-cAMP (Br-cAMP), a membrane-permeable cAMP analog, can mimic the similar effects produced by high glucose. Subsequently Br-cAMP could induce β-galactosidase (β-Gal) recombinant protein expression by 1.6-fold. Furthermore, Br-cAMP can additionally enhance the β-Gal production (from 2.8- to 4.5-fold) when CHO cells were stimulated with glycerol, thymidine, dimethyl sulfoxide, pentanoic acid, or sodium butyrate. Thus, Br-cAMP may be used as an alternative agent in promoting foreign protein expression for CHO cells. Copyright © 2017. Published by Elsevier B.V.

  13. Inhibition of protein kinase CK2 reduces CYP24A1 expression and enhances 1,25-dihydroxyvitamin D3 anti-tumor activity in human prostate cancer cells

    Science.gov (United States)

    Luo, Wei; Yu, Wei-Dong; Ma, Yingyu; Chernov, Mikhail; Trump, Donald L.; Johnson, Candace S.

    2013-01-01

    Vitamin D has broad range of physiological functions and anti-tumor effects. 24-hydroxylase, encoded by the CYP24A1 gene, is the key enzyme for degrading many forms of vitamin D including the most active form, 1,25D3. Inhibition of CYP24A1 enhances 1,25D3 anti-tumor activity. In order to isolate regulators of CYP24A1 expression in prostate cancer cells, we established a stable prostate cancer cell line PC3 with CYP24A1 promoter driving luciferase expression to screen a small molecular library for compounds that inhibit CYP24A1 promoter activity. From this screening, we identified, 4,5,6,7-tetrabromobenzimidazole (TBBz), a protein kinase CK2 selective inhibitor as a disruptor of CYP24A1 promoter activity. We show that TBBz inhibits CYP24A1 promoter activity induced by 1,25D3 in prostate cancer cells. In addition, TBBz downregulates endogenous CYP24A1 mRNA level in TBBz treated PC3 cells. Furthermore, siRNA-mediated CK2 knockdown reduces 1,25D3 induced CYP24A1 mRNA expression in PC3 cells. These results suggest that CK2 contributes to 1,25D3 mediated target gene expression. Lastly, inhibition of CK2 by TBBz or CK2 siRNA significantly enhanced 1,25D3 mediated anti-proliferative effect in vitro and in vivo in a xenograft model. In summary, our findings reveal that protein kinase CK2 is involved in the regulation of CYP24A1 expression by 1,25D3 and CK2 inhibitor enhances 1,25D3 mediated anti-tumor effect. PMID:23358686

  14. Dinitrobenzamide mustard prodrugs - hypoxic cytotoxins and dual substrates for E.coli nitroreductase

    International Nuclear Information System (INIS)

    Patterson, A.V.; Hogg, A.; Pullen, S.; Degenkolbe, A.; Li, D.; Chappell, A.; Ying, S.; Atwell, G.J.; Denny, W.A.; Anderson, R.F.; Wilson, W.R.

    2003-01-01

    Conditional replicating adenoviral vectors (CRAds) have received considerable attention as therapeutic tools in combination with radiotherapy. Viral distribution and micro-regional geometry are likely to be important issues in the treatment of human solid tumours with gene therapy, particularly following intravenous virus administration. The use of CRAds that are 'armed' with enzyme/prodrug systems may overcome some of the perceived limitations; CRAds can redistribute and self-amplify in a cytolytic fashion whilst prodrug metabolites may elicit a local bystander effect. Either or both of these cytotoxic properties could have favourable interactions with radiotherapy (IR). Nevertheless, they may be insufficient to avoid pockets of vector-naive tumour cells beyond the diffusion limits of cytotoxic prodrug metabolites, such as when perivascular seeding occurs. Under such circumstances hypoxic tumour cells may represent the least accessible compartment for vector transfection; the same tumour subpopulation that is likely to be radioresistant. E.coli nitroreductase (NTR) can bioactivate dinitrobenzamide mustards (DNBMs) and is a promising enzyme/prodrug system for 'arming' CRAds. Notably DNMBs can also be activated by endogenous human reductases under low oxygen conditions providing an opportunity to identify dual hypoxic cytotoxins/NTR substrates that may circumvent some of the geometry issues and provide complementarity with IR. To identify a prodrug for NTR that is also active as a hypoxic cytotoxin in vivo. From a set of 164 DNB prodrugs, 19 with favourable activity in vitro against a panel of four NTR-expressing cancer cells were selected and screened for activity as hypoxic cytotoxins in vitro. Measured E17 values ranged from -444 to -366 mV. Seven DNBMs possessed acceptable hypoxic selectivity against the human NSCLC cell line A549WT or clones engineered to overexpress either a human single-electron reductase, cytochrome P450 reductase (A549P450R), or oxic

  15. Synthesis of mutual azo prodrugs of anti-inflammatory agents and peptides facilitated by α-aminoisobutyric acid.

    Science.gov (United States)

    Kennedy, David A; Vembu, Nagarajan; Fronczek, Frank R; Devocelle, Marc

    2011-12-02

    Reported is the synthesis of azo mutual prodrugs of the nonsteroidal anti-inflammatory agents (NSAIDs) 4-aminophenylacetic acid (4-APAA) or 5-aminosalicylic acid (5-ASA) with peptides, including an antibiotic peptide temporin analogue modified at the amino terminal by an α-aminoisobutyric acid (Aib) residue. These prodrugs are designed for colonic delivery of two agents to treat infection and inflammation by the bacterial pathogen Clostridium difficile . © 2011 American Chemical Society

  16. Thymidine kinases in archaea

    DEFF Research Database (Denmark)

    Clausen, A.R.; Matakos, A.; Sandrini, Michael

    2006-01-01

    Twenty-six fully sequenced archaeal genomes were searched for genes coding for putative deoxyribonucleoside kinases (dNKs). We identified only 5 human-like thymidine kinase 1 genes (TK1s) and none for non-TK1 kinases. Four TK1s were identified in the Euryarchaea and one was found in the Crenarcha...

  17. Prodrugs of purine and pyrimidine analogues for the intestinal di/tri-peptide transporter PepT1

    DEFF Research Database (Denmark)

    Thomsen, Anne Engelbrecht; Friedrichsen, Gerda Marie; Sørensen, Arne Hagsten

    2003-01-01

    , novel L-Glu-Sar and D-Glu-Ala ester prodrugs of acyclovir and 1-(2-hydroxyethyl)-linked thymine were synthesized and their affinities for hPepT1 in Caco-2 cells were determined. Furthermore, the degradation of the prodrugs was investigated in various aqueous and biological media and compared...... to the corresponding hydrolysis of the prodrug valaciclovir. Affinity studies showed that the L-Glu-Sar prodrugs had high affinity for hPepT1 (K(i) approximately 0.2-0.3 mM), whereas the D-Glu-Ala prodrugs had poor affinity (K(i) approximately 50 mM). The pH-rate profiles of the prodrugs D-Glu[1-(2-hydroxyethyl......)thymine]-Ala and L-Glu[acyclovir]-Sar showed specific base catalyzed degradation at pH above 4.5 and 5.5, respectively. This implicates that the degradation rates at pH approximately 7.4 (t(1/2) approximately 3.5 and 5.5 h) are approximately 25 times faster than at upper small intestinal pH approximately 6.0. In 10...

  18. Novel L-Dopa and dopamine prodrugs containing a 2-phenyl-imidazopyridine moiety.

    Science.gov (United States)

    Denora, Nunzio; Laquintana, Valentino; Lopedota, Angela; Serra, Mariangela; Dazzi, Laura; Biggio, Giovanni; Pal, Dhananjay; Mitra, Ashim K; Latrofa, Andrea; Trapani, Giuseppe; Liso, Gaetano

    2007-07-01

    The aim of this study was to gain insight into the feasibility of enhancing the delivery of L-Dopa and dopamine to the brain by linking these neurotransmitters and L-Dopa ethyl ester to 2-phenyl-3-carboxymethyl-imidazopyridine compounds giving rise to the so-called Dopimid compounds. A number of Dopimid compounds were synthesized and both stability and binding studies to dopaminergic and benzodiazepine receptors were performed. To evaluate whether Dopimid compounds are P-gp substrates, [(3)H]ritonavir uptake experiments and bi-directional transport studies on confluent MDCKII-MDR1 monolayers were carried out. The brain penetration properties of Dopimid compounds were estimated by the Clark's computational model and evaluated by investigation of their transport across BBMECs monolayers. The dopamine levels following the intraperitoneal administration of the selected Dopimid compounds were measured in vivo by using brain microdialysis in rat. Tested compounds were adequately stable in solution buffered at pH 7.4 but undergo faster cleavage in dilute rat serum at 37 degrees C. Receptor binding studies showed that Dopimid compounds are essentially devoid of affinity for dopaminergic and benzodiazepine receptors. [(3)H]ritonavir uptake experiments indicated that selected Dopimid compounds, like L-Dopa and dopamine hydrochloride, are not substrates of P-gp and it was also confirmed by bi-directional transport experiments across MDCKII-MDR1 monolayers. By Clark's model a significant brain penetration was deduced for L-Dopa ethyl ester and dopamine derivatives. Transport studies involving BBMECs monolayers indicated that some of these compounds should be able to cross the BBB. Interestingly, the rank order of apparent permeability (P (app)) values observed in these assays parallels that calculated by the computational approach. Brain microdialysis experiments in rat showed that intraperitoneal acute administration of some Dopimid compounds induced a dose-dependent increase

  19. Copper-free click-chemistry platform to functionalize cisplatin prodrugs.

    Science.gov (United States)

    Pathak, Rakesh K; McNitt, Christopher D; Popik, Vladimir V; Dhar, Shanta

    2014-06-02

    The ability to rationally design and construct a platform technology to develop new platinum(IV) [Pt(IV)] prodrugs with functionalities for installation of targeting moieties, delivery systems, fluorescent reporters from a single precursor with the ability to release biologically active cisplatin by using well-defined chemistry is critical for discovering new platinum-based therapeutics. With limited numbers of possibilities considering the sensitivity of Pt(IV) centers, we used a strain-promoted azide-alkyne cycloaddition approach to provide a platform, in which new functionalities can easily be installed on cisplatin prodrugs from a single Pt(IV) precursor. The ability of this platform to be incorporated in nanodelivery vehicle and conjugation to fluorescent reporters were also investigated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Acyclovir prodrug for the intestinal di/tri-peptide transporter PEPT1

    DEFF Research Database (Denmark)

    Thomsen, Anne Engelbrecht; Christensen, Michael Søberg; Bagger, Morten Aavad

    2004-01-01

    It has previously been shown that the prodrug Glu(acyclovir)-Sar has a high affinity for PEPT1 in Caco-2 cells. However, affinity does not necessarily lead to translocation by the transporter which is necessary for achieving an increased oral bioavailability. Therefore i.v. and p.o. doses of Glu......(acyclovir)-Sar, acyclovir and valacyclovir were given to rats and the collected blood samples were analysed via LC-MS-MS. Furthermore, Caco-2 cell monolayers were exposed apically to Glu(acyclovir)-Sar, acyclovir, and valacyclovir and the concentration of drug and prodrugs in the cell extracts were determined and taken...... as a measure for intracellular accumulation. In addition, bi-directional transport studies of Glu(acyclovir)-Sar across Caco-2 cell monolayers and in vitro metabolism studies of Glu(acyclovir)-Sar in various media of rat origin were performed. For these purposes HPLC-UV analysis was applied. Oral...

  1. Pharmacokinetics of penciclovir after oral administration of its prodrug famciclovir to horses.

    Science.gov (United States)

    Tsujimura, Koji; Yamada, Masayuki; Nagata, Shun-ichi; Yamanaka, Takashi; Nemoto, Manabu; Kondo, Takashi; Kurosawa, Masahiko; Matsumura, Tomio

    2010-03-01

    We investigated the pharmacokinetics of penciclovir after oral administration of its prodrug famciclovir to horses. Following an oral dose of famciclovir at 20 mg/kg, maximum plasma concentrations of penciclovir occurred between 0.75 and 1.5 hr (mean 0.94 + or - 0.38 hr) after dosing and were in the range 2.22 to 3.56 microg/ml (mean 2.87 + or - 0.61 microg/ml). The concentrations of penciclovir declined in a biphasic manner after the peak concentration was attained. The mean half-life of the rapid elimination phase was 1.73 + or - 0.34 hr whereas that of the slow elimination phase was 34.34 + or - 13.93 hr. These pharmacokinetic profiles observed were similar to those of another antiherpesvirus drug, acyclovir, previously reported in horses following oral dosing of its prodrug valacyclovir.

  2. Fabrication of Reductive-Responsive Prodrug Nanoparticles with Superior Structural Stability by Polymerization-Induced Self-Assembly and Functional Nanoscopic Platform for Drug Delivery.

    Science.gov (United States)

    Zhang, Wen-Jian; Hong, Chun-Yan; Pan, Cai-Yuan

    2016-09-12

    A highly efficient strategy, polymerization-induced self-assembly (PISA) for fabrication of the polymeric drug delivery systems in cancer chemotherapy is reported. Diblock prodrug copolymer, PEG-b-P(MEO2MA-co-CPTM) was used as the macro-RAFT agent to fabricate prodrug nanoparticles through PISA. The advantages of fabricating intelligent drug delivery system via this approach are as following: (1) Simultaneous fulfillment of polymerization, self-assembly, and drug encapsulation in one-pot at relatively high concentration (100 mg/mL); (2) Almost complete monomer conversion allows direct application of the resultant prodrug nanoparticles without further purification; (3) Robust structures of the resultant prodrug nanoparticles, because the cross-linker was used as the comonomer, resulted in core-cross-linking simultaneously with the formation of the prodrug nanoparticles; (4) The drug content in the resultant prodrug nanoparticles can be accurately modulated just via adjusting the feed molar ratio of MEO2MA/CPTM in the synthesis of PEG-b-P(MEO2MA-co-CPTM). The prodrug nanoparticles with similar diameters but various drug contents were obtained using different prodrug macro-CTA. In consideration of the long-term biological toxicity, the prodrug nanoparticles with higher drug content exhibit more excellent anticancer efficiency due to that lower dosage of them are enough for effectively killing HeLa cells.

  3. HDAC inhibition amplifies gap junction communication in neural progenitors: Potential for cell-mediated enzyme prodrug therapy

    International Nuclear Information System (INIS)

    Khan, Zahidul; Akhtar, Monira; Asklund, Thomas; Juliusson, Bengt; Almqvist, Per M.; Ekstroem, Tomas J.

    2007-01-01

    Enzyme prodrug therapy using neural progenitor cells (NPCs) as delivery vehicles has been applied in animal models of gliomas and relies on gap junction communication (GJC) between delivery and target cells. This study investigated the effects of histone deacetylase (HDAC) inhibitors on GJC for the purpose of facilitating transfer of therapeutic molecules from recombinant NPCs. We studied a novel immortalized midbrain cell line, NGC-407 of embryonic human origin having neural precursor characteristics, as a potential delivery vehicle. The expression of gap junction protein connexin 43 (C x 43) was analyzed by western blot and immunocytochemistry. While C x 43 levels were decreased in untreated differentiating NGC-407 cells, the HDAC inhibitor 4-phenylbutyrate (4-PB) increased C x 43 expression along with increased membranous deposition in both proliferating and differentiating cells. Simultaneously, Ser 279/282-phosphorylated form of C x 43 was declined in both culture conditions by 4-PB. The 4-PB effect in NGC-407 cells was verified by using HNSC.100 human neural progenitors and Trichostatin A. Improved functional GJC is of imperative importance for therapeutic strategies involving intercellular transport of low molecular-weight compounds. We show here an enhancement by 4-PB, of the functional GJC among NGC-407 cells, as well as between NGC-407 and human glioma cells, as indicated by increased fluorescent dye transfer

  4. Two-step polymer- and liposome-enzyme prodrug therapies for cancer: PDEPT and PELT concepts and future perspectives.

    Science.gov (United States)

    Scomparin, Anna; Florindo, Helena F; Tiram, Galia; Ferguson, Elaine L; Satchi-Fainaro, Ronit

    2017-09-01

    Polymer-directed enzyme prodrug therapy (PDEPT) and polymer enzyme liposome therapy (PELT) are two-step therapies developed to provide anticancer drugs site-selective intratumoral accumulation and release. Nanomedicines, such as polymer-drug conjugates and liposomal drugs, accumulate in the tumor site due to extravasation-dependent mechanism (enhanced permeability and retention - EPR - effect), and further need to cross the cellular membrane and release their payload in the intracellular compartment. The subsequent administration of a polymer-enzyme conjugate able to accumulate in the tumor tissue and to trigger the extracellular release of the active drug showed promising preclinical results. The development of polymer-enzyme, polymer-drug conjugates and liposomal drugs had undergone a vast advancement over the past decades. Several examples of enzyme mimics for in vivo therapy can be found in the literature. Moreover, polymer therapeutics often present an enzyme-sensitive mechanism of drug release. These nanomedicines can thus be optimal substrates for PDEPT and this review aims to provide new insights and stimuli toward the future perspectives of this promising combination. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Strategy for Imidazotetrazine Prodrugs with Anticancer Activity Independent of MGMT and MMR

    Science.gov (United States)

    2012-01-01

    The imidazotetrazine ring is an acid-stable precursor and prodrug of highly reactive alkyl diazonium ions. We have shown that this reactivity can be managed productively in an aqueous system for the generation of aziridinium ions with 96% efficiency. The new compounds are potent DNA alkylators and have antitumor activity independent of the O6-methylguanine-DNA methyltransferase and DNA mismatch repair constraints that limit the use of Temozolomide. PMID:24900418

  6. Construction and cellular uptake behavior of redox-sensitive docetaxel prodrug-loaded liposomes.

    Science.gov (United States)

    Ren, Guolian; Jiang, Mengjuan; Guo, Weiling; Sun, Bingjun; Lian, He; Wang, Yongjun; He, Zhonggui

    2018-01-01

    A redox-responsive docetaxel (DTX) prodrug consisting of a disulfide linkage between DTX and vitamin E (DTX-SS-VE) was synthesized in our laboratory and was successfully formulated into liposomes. The aim of this study was to optimize the formulation and investigate the cellular uptake of DTX prodrug-loaded liposomes (DPLs). The content of DTX-SS-VE was determined by ultrahigh-performance liquid chromatography (UPLC). The formulation and process were optimized using entrapment efficiency (EE), drug-loading (DL), particle size and polydispersity index (PDI) as the evaluation indices. The optimal formulation was as follows: drug/lipid ratio of 1:12, cholesterol/lipid ratio of 1:10, hydration temperature of 40 °C, sonication power and time of 400 W and 5 min. The EE, DL and particle size of the optimized DPLs were 97.60 ± 0.03%, 7.09 ± 0.22% and 93.06 ± 0.72 nm, respectively. DPLs had good dilution stability under the physiological conditions over 24 h. In addition, DPLs were found to enter tumor cells via different pathways and released DTX from the prodrug to induce apoptosis. Taken together, the optimized formulation and process were found to be a simple, stable and applicable method for the preparation of DPLs that could successfully escape from lysosomes.

  7. Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications.

    Science.gov (United States)

    Massaro, M; Amorati, R; Cavallaro, G; Guernelli, S; Lazzara, G; Milioto, S; Noto, R; Poma, P; Riela, S

    2016-04-01

    Covalently functionalized halloysite nanotubes (HNTs) were successfully employed as dual-responsive nanocarriers for curcumin (Cur). Particularly, we synthesized HNT-Cur prodrug with a controlled curcumin release on dependence of both intracellular glutathione (GSH) and pH conditions. In order to obtain HNT-Cur produgs, halloysite was firstly functionalized with cysteamine through disulphide linkage. Afterwards, curcumin molecules were chemically conjugated to the amino end groups of halloysite via Schiff's base formation. The successful functionalization of halloysite was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and scanning electron microscopy. Experimental data confirmed the presence of curcumin on HNT external surface. Moreover, we investigated the kinetics of curcumin release by UV-vis spectroscopy, which highlighted that HNT-Cur prodrug possesses dual stimuli-responsive ability upon exposure to GSH-rich or acidic environment. In vitro antiproliferative and antioxidant properties of HNT-Cur prodrug were studied with the aim to explore their potential applications in pharmaceutics. This work puts forward an efficient strategy to prepare halloysite based nanocarriers with controlled drug delivery capacity through direct chemical grafting with stimuli-responsive linkage. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Synthesis and biological evaluation of novel 10-substituted-7-ethyl-10-hydroxycamptothecin (SN-38) prodrugs.

    Science.gov (United States)

    Zhou, Mo; Liu, Meixia; He, Xinhua; Yu, Hong; Wu, Di; Yao, Yishan; Fan, Shiyong; Zhang, Ping; Shi, Weiguo; Zhong, Bohua

    2014-11-27

    In an attempt to improve the antitumor activity and reduce the side effects of irinotecan (2), novel prodrugs of SN-38 (3) were prepared by conjugating amino acids or dipeptides to the 10-hydroxyl group of SN-38 via a carbamate linkage. The synthesized compounds completely generated SN-38 in pH 7.4 buffer or in human plasma, while remaining stable under acidic conditions. All prodrug compounds demonstrated much greater in vitro antitumor activities against HeLa cells and SGC-7901 cells than irinotecan. The most active compounds, 5h, 7c, 7d, and 7f, exhibited IC50 values that were 1000 times lower against HeLa cells and 30 times lower against SGC-7901 cells than those of irinotecan, and the inhibitory activities of these prodrugs against acetylcholinesterase (AchE) were significantly reduced, with IC50 values more than 6.8 times greater than that of irinotecan. In addition, compound 5e exhibited the same level of tumor growth inhibitory activity as irinotecan (CPT-11) in a human colon xenograft model in vivo.

  9. Synthesis and Biological Evaluation of Novel 10-Substituted-7-ethyl-10-hydroxycamptothecin (SN-38 Prodrugs

    Directory of Open Access Journals (Sweden)

    Mo Zhou

    2014-11-01

    Full Text Available In an attempt to improve the antitumor activity and reduce the side effects of irinotecan (2, novel prodrugs of SN-38 (3 were prepared by conjugating amino acids or dipeptides to the 10-hydroxyl group of SN-38 via a carbamate linkage. The synthesized compounds completely generated SN-38 in pH 7.4 buffer or in human plasma, while remaining stable under acidic conditions. All prodrug compounds demonstrated much greater in vitro antitumor activities against HeLa cells and SGC-7901 cells than irinotecan. The most active compounds, 5h, 7c, 7d, and 7f, exhibited IC50 values that were 1000 times lower against HeLa cells and 30 times lower against SGC-7901 cells than those of irinotecan, and the inhibitory activities of these prodrugs against acetylcholinesterase (AchE were significantly reduced, with IC50 values more than 6.8 times greater than that of irinotecan. In addition, compound 5e exhibited the same level of tumor growth inhibitory activity as irinotecan (CPT-11 in a human colon xenograft model in vivo.

  10. A prodrug-doped cellular Trojan Horse for the potential treatment of prostate cancer.

    Science.gov (United States)

    Levy, Oren; Brennen, W Nathaniel; Han, Edward; Rosen, David Marc; Musabeyezu, Juliet; Safaee, Helia; Ranganath, Sudhir; Ngai, Jessica; Heinelt, Martina; Milton, Yuka; Wang, Hao; Bhagchandani, Sachin H; Joshi, Nitin; Bhowmick, Neil; Denmeade, Samuel R; Isaacs, John T; Karp, Jeffrey M

    2016-06-01

    Despite considerable advances in prostate cancer research, there is a major need for a systemic delivery platform that efficiently targets anti-cancer drugs to sites of disseminated prostate cancer while minimizing host toxicity. In this proof-of-principle study, human mesenchymal stem cells (MSCs) were loaded with poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) that encapsulate the macromolecule G114, a thapsigargin-based prostate specific antigen (PSA)-activated prodrug. G114-particles (∼950 nm in size) were internalized by MSCs, followed by the release of G114 as an intact prodrug from loaded cells. Moreover, G114 released from G114 MP-loaded MSCs selectively induced death of the PSA-secreting PCa cell line, LNCaP. Finally, G114 MP-loaded MSCs inhibited tumor growth when used in proof-of-concept co-inoculation studies with CWR22 PCa xenografts, suggesting that cell-based delivery of G114 did not compromise the potency of this pro-drug in-vitro or in-vivo. This study demonstrates a potentially promising approach to assemble a cell-based drug delivery platform, which inhibits cancer growth in-vivo without the need of genetic engineering. We envision that upon achieving efficient homing of systemically infused MSCs to cancer sites, this MSC-based platform may be developed into an effective, systemic 'Trojan Horse' therapy for targeted delivery of therapeutic agents to sites of metastatic PCa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. The antiproliferative cytostatic effects of a self-activating viridin prodrug

    Science.gov (United States)

    Smith, Adam; Blois, Joseph; Yuan, Hushan; Aikawa, Elena; Ellson, Christian; Figueiredo, Jose-Luiz; Weissleder, Ralph; Kohler, Rainer; Yaffe, Michael B.; Cantley, Lewis C.; Josephson, Lee

    2009-01-01

    Although viridins like wortmannin (Wm) have long been examined as anticancer agents, their ability to self-activate has only recently been recognized. Here, we describe the cytostatic effects of a self-activating viridin (SAV), which is an inactive, polymeric prodrug. SAV self-activates to generate a bioactive, fluorescent viridin NBD-Wm with a half-time of 9.2 hours. With cultured A549 cells, 10 µmol/L SAV caused growth arrest without inducing apoptosis or cell death, a cytostatic action markedly different from other chemotherapeutic agents (vinblastine, camptothecin, and paclitaxel). In vivo, a SAV dosing of 1 mg/kg once in 48 hours (i.p.) resulted in growth arrest of an A549 tumor xenograft, with growth resuming when dosing ceased. With a peak serum concentration of SAV of 2.36 µmol/L (at 2 hours post i.p. injection), the concentration of bioactive NBD-Wm was 41 nmol/L based on the partial inhibition of neutrophil respiratory burst. Therefore, SAV was present as an inactive prodrug in serum (peak = 2.36 µmol/L), which generated low concentrations of active viridin (41 nmol/L). SAV is a prodrug, the slowrelease and cytostatic activities of which suggest that it might be useful as a component of metronomic-based chemotherapeutic strategies. PMID:19509266

  12. Improved synthesis of N-benzylaminoferrocene-based prodrugs and evaluation of their toxicity and antileukemic activity.

    Science.gov (United States)

    Daum, Steffen; Chekhun, Vasiliy F; Todor, Igor N; Lukianova, Natalia Yu; Shvets, Yulia V; Sellner, Leopold; Putzker, Kerstin; Lewis, Joe; Zenz, Thorsten; de Graaf, Inge A M; Groothuis, Geny M M; Casini, Angela; Zozulia, Oleksii; Hampel, Frank; Mokhir, Andriy

    2015-02-26

    We report on an improved method of synthesis of N-benzylaminoferrocene-based prodrugs and demonstrate its applicability by preparing nine new aminoferrocenes. Their effect on the viability of selected cancer cells having different p53 status was studied. The obtained data are in agreement with the hypothesis that the toxicity of aminoferrocenes is not dependent upon p53 status. Subsequently the toxicity of a selected prodrug (4) was investigated ex vivo using rat precision cut liver slices and in vivo on hybrid male mice BDF1. In both experiments no toxicity was observed: ex vivo, up to 10 μM; in vivo, up to 6 mg/kg. Finally, prodrug 4 was shown to extend the survival of BDF1 mice carrying L1210 leukemia from 13.7 ± 0.6 days to 17.5 ± 0.7 days when injected daily 6 times at a dose of 26 μg/kg starting from the second day after injection of L1210 cells.

  13. A unique highly hydrophobic anticancer prodrug self-assembled nanomedicine for cancer therapy.

    Science.gov (United States)

    Ren, Guolian; Jiang, Mengjuan; Xue, Peng; Wang, Jing; Wang, Yongjun; Chen, Bo; He, Zhonggui

    2016-11-01

    In contrast with common thought, we generated highly hydrophobic anticancer prodrug self-assembled nanoparticles without the aid of surface active substances, based on the conjugation of docetaxel to d-α-tocopherol succinate. The reduction-sensitive prodrug was synthesized with a disulfide bond inserted into the linker and was compared with a control reduction-insensitive prodrug. The morphology and stability of self-assembled nanoparticles were investigated. Cytotoxicity and apoptosis assays showed that the reduction-sensitive nanoparticles had higher anticancer activity than the reduction-insensitive nanoparticles. The reduction-sensitive nanoparticles exhibited favorable in vivo antitumor activity and tolerance compared with docetaxel Tween80-containing formulation and the reduction-insensitive nanoparticles. Taken together, the unique nanomedicine demonstrated a number of advantages: (i) ease and reproducibility of preparation, (ii) high drug payload, (iii) superior stability, (iv) prolonged circulation, and (v) improved therapeutic effect. This highly reproducible molecular assembly strategy should motivate the development of new nanomedicines. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Whey protein concentrate enhances intestinal integrity and influences transforming growth factor-β1 and mitogen-activated protein kinase signalling pathways in piglets after lipopolysaccharide challenge.

    Science.gov (United States)

    Xiao, Kan; Jiao, Lefei; Cao, Shuting; Song, Zehe; Hu, Caihong; Han, Xinyan

    2016-03-28

    Whey protein concentrate (WPC) has been reported to have protective effects on the intestinal barrier. However, the molecular mechanisms involved are not fully elucidated. Transforming growth factor-β1 (TGF-β1) is an important component in the WPC, but whether TGF-β1 plays a role in these processes is not clear. The aim of this study was to investigate the protective effects of WPC on the intestinal epithelial barrier as well as whether TGF-β1 is involved in these protection processes in a piglet model after lipopolysaccharide (LPS) challenge. In total, eighteen weanling pigs were randomly allocated to one of the following three treatment groups: (1) non-challenged control and control diet; (2) LPS-challenged control and control diet; (3) LPS+5 %WPC diet. After 19 d of feeding with control or 5 %WPC diets, pigs were injected with LPS or saline. At 4 h after injection, pigs were killed to harvest jejunal samples. The results showed that WPC improved (Pprotein, phosphorylated-Smad2 expression and Smad4 and Smad7 mRNA expressions and decreased (Pprotein kinase signalling pathways.

  15. CyclinG1 Amplification Enhances Aurora Kinase Inhibitor-Induced Polyploid Resistance and Inhibition of Bcl-2 Pathway Reverses the Resistance

    Directory of Open Access Journals (Sweden)

    Wenfeng Zhang

    2017-08-01

    Full Text Available Background/Aims: CyclinG1 (CycG1 is frequently overexpressed in solid tumors and overexpression of CycG1 promotes cell survival upon paclitaxel exposure by inducing polyploidy. Whether and how CycG1 regulates polyploidization caused by small molecular targeted inhibitors remains unclear. Methods: Immunohistochemistry and immunoblotting were utilized to examine protein expression. Cell proliferation was measured by ATPlite assay, and cell cycle distribution and apoptosis were measured by flow cytometry and/or DNA fragmentation assays. Results: Overexpression of CycG1 in breast cancer cells caused apoptosis-resistant polyploidy upon treatment with Aurora kinase inhibitor, ZM447439 (ZM. Addition of ABT-263, a small-molecule BH3 mimetic, to ZM, produced a synergistic loss of cell viability with greater sustained tumor growth inhibition in breast cancer cell lines. Decrease of Mcl-1 and increase of NOXA caused by ZM treatment, were responsible for the synergy. Furthermore, CycG1 was highly expressed in Triple-Negative-Breast-Cancer patients treated with paclitaxel and was paralleled by decreased cell survival. Conclusion: CycG1 is a crucial factor in ZM-induced polyploidy resistance, and ABT-263/ZM combination hold therapeutic utility in the CycG1-amplified subset of breast cancer and CycG1, thus, is a promising target in breast cancer.

  16. Sodium Phenylbutyrate Enhances Astrocytic Neurotrophin Synthesis via Protein Kinase C (PKC)-mediated Activation of cAMP-response Element-binding Protein (CREB)

    Science.gov (United States)

    Corbett, Grant T.; Roy, Avik; Pahan, Kalipada

    2013-01-01

    Neurotrophins, such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), are believed to be genuine molecular mediators of neuronal growth and homeostatic synapse activity. However, levels of these neurotrophic factors decrease in different brain regions of patients with Alzheimer disease (AD). Induction of astrocytic neurotrophin synthesis is a poorly understood phenomenon but represents a plausible therapeutic target because neuronal neurotrophin production is aberrant in AD and other neurodegenerative diseases. Here, we delineate that sodium phenylbutyrate (NaPB), a Food and Drug Administration-approved oral medication for hyperammonemia, induces astrocytic BDNF and NT-3 expression via the protein kinase C (PKC)-cAMP-response element-binding protein (CREB) pathway. NaPB treatment increased the direct association between PKC and CREB followed by phosphorylation of CREB (Ser133) and induction of DNA binding and transcriptional activation of CREB. Up-regulation of markers for synaptic function and plasticity in cultured hippocampal neurons by NaPB-treated astroglial supernatants and its abrogation by anti-TrkB blocking antibody suggest that NaPB-induced astroglial neurotrophins are functionally active. Moreover, oral administration of NaPB increased the levels of BDNF and NT-3 in the CNS and improved spatial learning and memory in a mouse model of AD. Our results highlight a novel neurotrophic property of NaPB that may be used to augment neurotrophins in the CNS and improve synaptic function in disease states such as AD. PMID:23404502

  17. The Phytochemical Bergenin Enhances T Helper 1 Responses and Anti-Mycobacterial Immunity by Activating the MAP Kinase Pathway in Macrophages

    Directory of Open Access Journals (Sweden)

    Debprasad Chattopadhyay

    2017-05-01

    Full Text Available Tuberculosis (TB remains one of the greatest health concerns worldwide, which has hindered socioeconomic development in certain parts of the world for many centuries. Although current TB therapy, “Directly Observed Treatment Short-course,” is effective, it is associated with unwanted side effects and the risk for the generation of drug-resistant organisms. The majority of infected individuals successfully confine the mycobacterial organisms and remain asymptotic unless immune responses are perturbed. Thus, host immunity can protect against TB and immunomodulation is therefore an attractive therapeutic option. Previous studies have shown that TNF-α and Nitric Oxide (NO in conjunction with IFN-γ-producing T helper 1 (Th1 cells play critical roles in host protection against TB. Here, we show that bergenin, a phytochemical isolated from tender leaves of Shorea robusta, activates the MAP kinase and ERK pathways and induces TNF-α, NO and IL-12 production in infected macrophages. We further show that bergenin induces Th1 immune responses and potently inhibits bacillary growth in a murine model of Mycobacterium tuberculosis infection. These findings identify bergenin as a potential adjunct to TB therapy.

  18. A conserved p38 MAP kinase pathway in Caenorhabditis elegans innate immunity.

    Science.gov (United States)

    Kim, Dennis H; Feinbaum, Rhonda; Alloing, Geneviève; Emerson, Fred E; Garsin, Danielle A; Inoue, Hideki; Tanaka-Hino, Miho; Hisamoto, Naoki; Matsumoto, Kunihiro; Tan, Man-Wah; Ausubel, Frederick M

    2002-07-26

    A genetic screen for Caenorhabditis elegans mutants with enhanced susceptibility to killing by Pseudomonas aeruginosa led to the identification of two genes required for pathogen resistance: sek-1, which encodes a mitogen-activated protein (MAP) kinase kinase, and nsy-1, which encodes a MAP kinase kinase kinase. RNA interference assays and biochemical analysis established that a p38 ortholog, pmk-1, functions as the downstream MAP kinase required for pathogen defense. These data suggest that this MAP kinase signaling cassette represents an ancient feature of innate immune responses in evolutionarily diverse species.

  19. Prodrugs designed to discriminate pathological (tumour) and physiological (normal tissue) hypoxia

    International Nuclear Information System (INIS)

    Wilson, W.R.; Patterson, A.V.

    2003-01-01

    There is now abundant evidence that hypoxic contributes to treatment failure in radiation therapy. As a target for therapeutic intervention, hypoxia is especially attractive because it is a common feature of most human tumours and therefore a potential 'pan target' across many tumour types. However, attempts to exploit hypoxia face the problem that oxygen concentrations in some normal tissues are also heterogeneous and that O 2 distributions in tumours and normal tissues overlap. Simply adjusting the K value (O 2 concentration for 50% inhibition of activation) does not provide a satisfactory solution. Bioreductive drugs like tirapazamine with high K values are activated significantly in several normal tissues, while nitro compounds and quinones with low K values spare the hypoxic tumour cells at 'intermediate' O 2 tensions (1-10 mM O 2 ) which are considered to be major contributors to tumour radioresistance. A potential strategy for overcoming this dilemma is to design prodrugs that are activated only at very low K values, but give relatively stable cytotoxic metabolites capable of diffusing to cells at higher O 2 concentrations. This approach redefines the therapeutic target as cells adjacent to zones of pathological hypoxia ( 2 ), providing discrimination from physiological hypoxia in normal tissues. Detecting bioreductive prodrugs capable of providing bystander killing of this kind is not straightforward. We have adapted a multicellular layer (MCL) co-culture model for quantifying bystander effects in GDEPT (Wilson et al., Cancer Res., 62: 1425-1432, 2002), and have used this to measure bystander effects of hypoxia-activated prodrugs. This model uses differences in metabolic activation of bioreductive drugs between A459 cell lines with low and high cytochrome P450 reductase activity, rather than O 2 gradients, to effect localised prodrug activation. It shows that TPZ and the nitroimidazole RSU-1069 have little or no bystander effect, but that dinitrobenzamide

  20. Loss of the receptor tyrosine kinase Axl leads to enhanced inflammation in the CNS and delayed removal of myelin debris during Experimental Autoimmune Encephalomyelitis

    Directory of Open Access Journals (Sweden)

    Prieto Anne L

    2011-05-01

    Full Text Available Abstract Background Axl, together with Tyro3 and Mer, constitute the TAM family of receptor tyrosine kinases. In the nervous system, Axl and its ligand Growth-arrest-specific protein 6 (Gas6 are expressed on multiple cell types. Axl functions in dampening the immune response, regulating cytokine secretion, clearing apoptotic cells and debris, and maintaining cell survival. Axl is upregulated in various disease states, such as in the cuprizone toxicity-induced model of demyelination and in multiple sclerosis (MS lesions, suggesting that it plays a role in disease pathogenesis. To test for this, we studied the susceptibility of Axl-/- mice to experimental autoimmune encephalomyelitis (EAE, an animal model for multiple sclerosis. Methods WT and Axl-/- mice were immunized with myelin oligodendrocyte glycoprotein (MOG35-55 peptide emulsified in complete Freund's adjuvant and injected with pertussis toxin on day 0 and day 2. Mice were monitored daily for clinical signs of disease and analyzed for pathology during the acute phase of disease. Immunological responses were monitored by flow cytometry, cytokine analysis and proliferation assays. Results Axl-/- mice had a significantly more severe acute phase of EAE than WT mice. Axl-/- mice had more spinal cord lesions with larger inflammatory cuffs, more demyelination, and more axonal damage than WT mice during EAE. Strikingly, lesions in Axl-/- mice had more intense Oil-Red-O staining indicative of inefficient clearance of myelin debris. Fewer activated microglia/macrophages (Iba1+ were found in and/or surrounding lesions in Axl-/- mice relative to WT mice. In contrast, no significant differences were noted in immune cell responses between naïve and sensitized animals. Conclusions These data show that Axl alleviates EAE disease progression and suggests that in EAE Axl functions in the recruitment of microglia/macrophages and in the clearance of debris following demyelination. In addition, these data

  1. Platinum(iv) prodrug conjugated Pd@Au nanoplates for chemotherapy and photothermal therapy

    Science.gov (United States)

    Shi, Saige; Chen, Xiaolan; Wei, Jingping; Huang, Yizhuan; Weng, Jian; Zheng, Nanfeng

    2016-03-01

    Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The prepared Pd@Au-PEG-Pt nanocomposite showed excellent stability in physiological solutions and efficient Pt(iv) prodrug loading. Once injected into biological tissue, the Pt(iv) prodrug was easily reduced by physiological reductants (e.g. ascorbic acid or glutathione) into its cytotoxic and hydrophilic Pt(ii) form and released from the original nanocomposite, and the NIR laser irradiation could accelerate the release of Pt(ii) species. More importantly, Pd@Au-PEG-Pt has high tumor accumulation (29%ID per g), which makes excellent therapeutic efficiency at relatively low power density possible. The in vivo results suggested that, compared with single therapy the combined thermo-chemotherapy treatment with Pd@Au-PEG-Pt resulted in complete destruction of the tumor tissue without recurrence, while chemotherapy using Pd@Au-PEG-Pt without irradiation or photothermal treatment using Pd@Au-PEG alone did not. Our work highlights the prospects of a feasible drug delivery strategy of the Pt prodrug by using 2D Pd@Au nanoplates as drug delivery carriers for multimode cancer treatment.Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The

  2. Critical determinant of intestinal permeability and oral bioavailability of pegylated all trans-retinoic acid prodrug-based nanomicelles: Chain length of poly (ethylene glycol) corona.

    Science.gov (United States)

    Li, Zhenbao; Han, Xiaopeng; Zhai, Yinglei; Lian, He; Zhang, Dong; Zhang, Wenjuan; Wang, Yongjun; He, Zhonggui; Liu, Zheng; Sun, Jin

    2015-06-01

    Pegylation method is widely used to prolong the blood circulation time of proteins and nanoparticles after intravenous administration, but the effect of surface poly (ethylene glycol) (PEG) chain length on oral absorption of the pegylated nanoparticles is poorly reported. The aim of our study was to investigate the influence of PEG corona chain length on membrane permeability and oral bioavailability of the amphiphilic pegylated prodrug-based nanomicelles, taking all trans-retinoic acid (ATRA) as a model drug. The amphiphilic ATRA-PEG conjugates were synthesized by esterification reaction between all trans-retinoic acid and mPEGs (mPEG500, mPEG1000, mPEG2000, and mPEG5000). The conjugates could self-assemble in aqueous medium to form nanomicelles by emulsion-solvent evaporation method. The resultant nanomicelles were in spherical shape with an average diameter of 13-20 nm. The drug loading efficiency of ATRA-PEG500, ATRA-PEG1000, ATRA-PEG2000, and ATRA-PEG5000 was about 38.4, 26.6, 13.1, and 5.68 wt%, respectively. With PEG chain length ranging from 500 to 5000, ATRA-PEG nanomicelles exhibited a bell shape of chemical stability in different pH buffers, intestinal homogenate and plasma. More importantly, they were all rapidly hydrolyzed into the parent drug in hepatic homogenate, with the half-time values being 0.3-0.4h. In comparison to ATRA solution and ATRA prodrug-based nanomicelles, ATRA-PEG1000 showed the highest intestinal permeability. After oral administration, ATRA-PEG2000 and ATRA-PEG5000 nanomicelles were not nearly absorbed, while the oral bioavailability of ATRA-PEG500 and ATRA-PEG1000 demonstrated about 1.2- and 2.0-fold higher than ATRA solution. Our results indicated that PEG1000 chain length of ATRA-PEG prodrug nanomicelles has the optimal oral bioavailability probably due to improved stability and balanced mucus penetration capability and cell binding, and that the PEG chain length on a surface of nanoparticles cannot exceed a key threshold with

  3. Suppression of inflammation in a mouse model of rheumatoid arthritis using targeted lipase-labile fumagillin prodrug nanoparticles.

    Science.gov (United States)

    Zhou, Hui-Fang; Yan, Huimin; Senpan, Angana; Wickline, Samuel A; Pan, Dipanjan; Lanza, Gregory M; Pham, Christine T N

    2012-11-01

    Nanoparticle-based therapeutics are emerging technologies that have the potential to greatly impact the treatment of many human diseases. However, drug instability and premature release from the nanoparticles during circulation currently preclude clinical translation. Herein, we use a lipase-labile (Sn 2) fumagillin prodrug platform coupled with a unique lipid surface-to-surface targeted delivery mechanism, termed contact-facilitated drug delivery, to counter the premature drug release and overcome the inherent photo-instability of fumagillin, an established anti-angiogenic agent. We show that α(v)β(3)-integrin targeted fumagillin prodrug nanoparticles, administered at 0.3 mg of fumagillin prodrug/kg of body weight suppress the clinical disease indices of KRN serum-mediated arthritis in a dose-dependent manner when compared to treatment with the control nanoparticles with no drug. This study demonstrates the effectiveness of this lipase-labile prodrug nanocarrier in a relevant preclinical model that approximates human rheumatoid arthritis. The lipase-labile prodrug paradigm offers a translatable approach that is broadly applicable to many targeted nanosystems and increases the translational potential of this platform for many diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Design, Synthesis and Biological Evaluation of Brain-Targeted Thiamine Disulfide Prodrugs of Ampakine Compound LCX001

    Directory of Open Access Journals (Sweden)

    Dian Xiao

    2016-04-01

    Full Text Available Ampakine compounds have been shown to reverse opiate-induced respiratory depression by activation of amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA glutamate receptors. However, their pharmacological exploitations are hindered by low blood-brain barrier (BBB permeability and limited brain distribution. Here, we explored whether thiamine disulfide prodrugs with the ability of “lock-in” can be used to solve these problems. A series of thiamine disulfide prodrugs 7a–7f of ampakine compound LCX001 was synthesized and evaluated. The trials in vitro showed that prodrugs 7e, 7d, 7f possessed a certain stability in plasma and quickly decomposed in brain homogenate by the disulfide reductase. In vivo, prodrug 7e decreased the peripheral distribution of LCX001 and significantly increased brain distribution of LCX001 after i.v. administration. This compound showed 2.23- and 3.29-fold greater increases in the AUC0-t and MRT0-t of LCX001 in brain, respectively, than did LCX001 itself. A preliminary pharmacodynamic study indicated that the required molar dose of prodrug 7e was only one eighth that of LCX001 required to achieve the same effect in mice. These findings provide an important reference to evaluate the clinical outlook of ampakine compounds.

  5. Chronic voluntary oral methamphetamine induces deficits in spatial learning and hippocampal protein kinase Mzeta with enhanced astrogliosis and cyclooxygenase-2 levels

    Directory of Open Access Journals (Sweden)

    Jorge A. Avila

    2018-02-01

    Full Text Available Methamphetamine (MA is an addictive drug with neurotoxic effects on the brain producing cognitive impairment and increasing the risk for neurodegenerative disease. Research has focused largely on examining the neurochemical and behavioral deficits induced by injecting relatively high doses of MA [30 mg/kg of body weight (bw] identifying the upper limits of MA-induced neurotoxicity. Accordingly, we have developed an appetitive mouse model of voluntary oral MA administration (VOMA based on the consumption of a palatable sweetened oatmeal mash containing a known amount of MA. This VOMA model is useful for determining the lower limits necessary to produce neurotoxicity in the short-term and long-term as it progresses over time. We show that mice consumed on average 1.743 mg/kg bw/hour during 3 hours, and an average of 5.23 mg/kg bw/day over 28 consecutive days on a VOMA schedule. Since this consumption rate is much lower than the neurotoxic doses typically injected, we assessed the effects of long-term chronic VOMA on both spatial memory performance and on the levels of neurotoxicity in the hippocampus. Following 28 days of VOMA, mice exhibited a significant deficit in short-term spatial working memory and spatial reference learning on the radial 8-arm maze (RAM compared to controls. This was accompanied by a significant decrease in memory markers protein kinase Mzeta (PKMζ, calcium impermeable AMPA receptor subunit GluA2, and the post-synaptic density 95 (PSD-95 protein in the hippocampus. Compared to controls, the VOMA paradigm also induced decreases in hippocampal levels of dopamine transporter (DAT and tyrosine hydroxylase (TH, as well as increases in dopamine 1 receptor (D1R, glial fibrillary acidic protein (GFAP and cyclooxygenase-2 (COX-2, with a decrease in prostaglandins E2 (PGE2 and D2 (PGD2. These results demonstrate that chronic VOMA reaching 146 mg/kg bw/28d induces significant hippocampal neurotoxicity. Future studies will evaluate

  6. A receptor-like kinase gene (GbRLK) from Gossypium barbadense enhances salinity and drought-stress tolerance in Arabidopsis.

    Science.gov (United States)

    Zhao, Jun; Gao, Yulong; Zhang, Zhiyuan; Chen, Tianzi; Guo, Wangzhen; Zhang, Tianzhen

    2013-08-06

    Cotton (Gossypium spp.) is widely cultivated due to the important economic value of its fiber. However, extreme environmental degradation impedes cotton growth and production. Receptor-like kinase (RLK) proteins play important roles in signal transduction and participate in a diverse range of processes in response to plant hormones and environmental cues. Here, we introduced an RLK gene (GbRLK) from cotton into Arabidopsis and investigated its role in imparting abiotic stress tolerance. GbRLK transcription was induced by exogenously supplied abscisic acid (ABA), salicylic acid, methyl jasmonate, mock drought conditions and high salinity. We cloned the promoter sequence of this gene via self-formed adaptor PCR. Sequence analysis revealed that the promoter region contains many cis-acting stress-responsive elements such as ABRE, W-Box, MYB-core, W-Box core, TCA-element and others. We constructed a vector containing a 1,890-bp sequence in the 5' region upstream of the initiation codon of this promoter and transformed it into Arabidopsis thaliana. GUS histochemical staining analysis showed that GbRLK was expressed mainly in leaf veins, petioles and roots of transgenic Arabidopsis, but not in the cotyledons or root hairs. GbRLK promoter activity was induced by ABA, PEG, NaCl and Verticillium dahliae. Transgenic Arabidopsis with constitutive overexpression of GbRLK exhibited a reduced rate of water loss in leaves in vitro, along with improved salinity and drought tolerance and increased sensitivity to ABA compared with non-transgenic Col-0 Arabidopsis. Expression analysis of stress-responsive genes in GbRLK Arabidopsis revealed that there was increased expression of genes involved in the ABA-dependent signaling pathway (AtRD20, AtRD22 and AtRD26) and antioxidant genes (AtCAT1, AtCCS, AtCSD2 and AtCSD1) but not ion transporter genes (AtNHX1, AtSOS1). GbRLK is involved in the drought and high salinity stresses pathway by activating or participating in the ABA signaling

  7. Sulfur mustard induced mast cell degranulation in mouse skin is inhibited by a novel anti-inflammatory and anticholinergic bifunctional prodrug.

    Science.gov (United States)

    Joseph, Laurie B; Composto, Gabriella M; Perez, Roberto M; Kim, Hong-Duck; Casillas, Robert P; Heindel, Ned D; Young, Sherri C; Lacey, Carl J; Saxena, Jaya; Guillon, Christophe D; Croutch, Claire R; Laskin, Jeffrey D; Heck, Diane E

    2018-09-01

    Sulfur mustard (SM, bis(2-chloroethyl sulfide) is a potent vesicating agent known to cause skin inflammation, necrosis and blistering. Evidence suggests that inflammatory cells and mediators that they generate are important in the pathogenic responses to SM. In the present studies we investigated the role of mast cells in SM-induced skin injury using a murine vapor cup exposure model. Mast cells, identified by toluidine blue staining, were localized in the dermis, adjacent to dermal appendages and at the dermal/epidermal junction. In control mice, 48-61% of mast cells were degranulated. SM exposure (1.4g/m 3 in air for 6min) resulted in increased numbers of degranulated mast cells 1-14days post-exposure. Treatment of mice topically with an indomethacin choline bioisostere containing prodrug linked by an aromatic ester-carbonate that targets cyclooxygenases (COX) enzymes and acetylcholinesterase (1% in an ointment) 1-14days after SM reduced skin inflammation and injury and enhanced tissue repair. This was associated with a decrease in mast cell degranulation from 90% to 49% 1-3days post SM, and from 84% to 44% 7-14days post SM. These data suggest that reduced inflammation and injury in response to the bifunctional indomethacin prodrug may be due, at least in part, to abrogating mast cell degranulation. The use of inhibitors of mast cell degranulation may be an effective strategy for mitigating skin injury induced by SM. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. A Smart Europium-Ruthenium Complex as Anticancer Prodrug: Controllable Drug Release and Real-Time Monitoring under Different Light Excitations.

    Science.gov (United States)

    Li, Hongguang; Xie, Chen; Lan, Rongfeng; Zha, Shuai; Chan, Chi-Fai; Wong, Wing-Yan; Ho, Ka-Lok; Chan, Brandon Dow; Luo, Yuxia; Zhang, Jing-Xiang; Law, Ga-Lai; Tai, William C S; Bünzli, Jean-Claude G; Wong, Ka-Leung

    2017-11-09

    A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λ irr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

  9. Muscle phosphorylase kinase deficiency

    DEFF Research Database (Denmark)

    Preisler, N; Orngreen, M C; Echaniz-Laguna, A

    2012-01-01

    To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD).......To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD)....

  10. Chlorzoxazone esters of some non-steroidal anti-inflammatory (NSAI) carboxylic acids as mutual prodrugs: design, synthesis, pharmacological investigations and docking studies.

    Science.gov (United States)

    Abdel-Azeem, Ahmed Z; Abdel-Hafez, Atef A; El-Karamany, Gamal S; Farag, Hassan H

    2009-05-15

    The discovery of the inducible isoform of cyclooxygenase enzyme (COX-2) spurred the search for anti-inflammatory agents devoid of the undesirable effects associated with classical NSAIDs. New chlorzoxazone ester prodrugs (6-8) of some acidic NSAIDs (1-3) were designed, synthesized and evaluated as mutual prodrugs with the aim of improving the therapeutic potency and retard the adverse effects of gastrointestinal origin. The structure of the synthesized mutual ester prodrugs (6-8) were confirmed by IR, (1)H NMR, mass spectroscopy (MS) and their purity was ascertained by TLC and elemental analyses. In vitro chemical stability revealed that the synthesized ester prodrugs (6-8) are chemically stable in hydrochloric acid buffer pH 1.2 as a non-enzymatic simulated gastric fluid (SGF) and in phosphate buffer pH 7.4 as non-enzymatic simulated intestinal fluid (SIF). In 80% human plasma, the mutual prodrugs were found to be susceptible to enzymatic hydrolysis at relatively faster rate (t(1/2) approximately 37 and 34 min for prodrugs 6 and 7, respectively). Mutual ester prodrugs (6-8) were evaluated for their anti-inflammatory and muscle relaxation activities. Scanning electromicrographs of the stomach showed that the ester prodrugs induced very little irritancy in the gastric mucosa of rats after oral administration for 4days. In addition, docking of the mutual ester prodrugs (6-8) into COX-2 active site was conducted in order to predict the affinity and orientation of these prodrugs at the enzyme active site.

  11. Circumvention of P-gp and MRP2 mediated efflux of lopinavir by a histidine based dipeptide prodrug.

    Science.gov (United States)

    Mandal, Abhirup; Pal, Dhananjay; Mitra, Ashim K

    2016-10-15

    This study was aimed to develop a novel Histidine-Leucine-Lopinavir (His-Leu-LPV) dipeptide prodrug and evaluate its potential for circumvention of P-gp and MRP2-mediated efflux of lopinavir (LPV) indicated for HIV-1 infection. His-Leu-LPV was synthesized following esterification of hydroxyl group of LPV and was identified by (1)H NMR and LCMS/MS techniques. Aqueous solubility, stability and cell cytotoxicity of prodrug was determined. Uptake and permeability studies were carried out using P-gp (MDCK-MDR1) and MRP2 (MDCK-MRP2) transfected cell lines. To further delineate prodrug uptake, prodrug interaction with influx transporters (PepT1 and PHT1) was determined. Enzymatic hydrolysis and reconversion of His-Leu-LPV to LPV was examined using Caco-2 cell homogenates. Aqueous solubility generated by the prodrug was markedly higher relative to unmodified LPV. Importantly, His-Leu-LPV displayed significantly lower affinity towards P-gp and MRP2 as evident from higher uptake and transport rates. [3H]-GlySar and [3H]-l-His uptake receded to approximately 30% in the presence of His-Leu-LPV supporting the PepT1/PHT1 mediated uptake process. A steady regeneration of LPV and Leu-LPV in Caco-2 cell homogenates indicated His-Leu-LPV undergoes both esterase and peptidase-mediated hydrolysis. Histidine based dipeptide prodrug approach can be an alternative strategy to improve LPV absorption across poorly permeable intestinal barrier. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. The Role of Bystander Effects in the Antitumor Activity of the Hypoxia-Activated Prodrug PR-104

    Science.gov (United States)

    Foehrenbacher, Annika; Patel, Kashyap; Abbattista, Maria R.; Guise, Chris P.; Secomb, Timothy W.; Wilson, William R.; Hicks, Kevin O.

    2013-01-01

    Activation of prodrugs in tumors (e.g., by bioreduction in hypoxic zones) has the potential to generate active metabolites that can diffuse within the tumor microenvironment. Such “bystander effects” may offset spatial heterogeneity in prodrug activation but the relative importance of this effect is not understood. Here, we quantify the contribution of bystander effects to antitumor activity for the first time, by developing a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD) model for PR-104, a phosphate ester pre-prodrug that is converted systemically to the hypoxia-activated prodrug PR-104A. Using Green’s function methods we calculated concentrations of oxygen, PR-104A and its active metabolites, and resultant cell killing, at each point of a mapped three-dimensional tumor microregion. Model parameters were determined in vitro, using single cell suspensions to determine relationships between PR-104A metabolism and clonogenic cell killing, and multicellular layer (MCL) cultures to measure tissue diffusion coefficients. LC-MS/MS detection of active metabolites in the extracellular medium following exposure of anoxic single cell suspensions and MCLs to PR-104A confirmed that metabolites can diffuse out of cells and through a tissue-like environment. The SR-PK/PD model estimated that bystander effects contribute 30 and 50% of PR-104 activity in SiHa and HCT116 tumors, respectively. Testing the model by modulating PR-104A-activating reductases and hypoxia in tumor xenografts showed overall clonogenic killing broadly consistent with model predictions. Overall, our data suggest that bystander effects are important in PR-104 antitumor activity, although their reach may be limited by macroregional heterogeneity in hypoxia and reductase expression in tumors. The reported computational and experimental techniques are broadly applicable to all targeted anticancer prodrugs and could be used to identify strategies for rational prodrug optimization. PMID

  13. Enhanced delivery of ketobemidone through porcine buccal mucosa in vitro via more lipophilic ester prodrugs

    DEFF Research Database (Denmark)

    Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

    1992-01-01

    of permeation relative to ketobemidone, the permeability coefficients being 3-30-times higher than that of ketobemidone. The permeability coefficients increased with increasing lipophilicity, expressed in terms of octanol-buffer (pH 7.4) partition coefficients (P), up to log P values of about 1.5 whereupon...

  14. In vivo evaluation of lipid-based formulations for oral delivery of apomorphine and its diester prodrugs

    DEFF Research Database (Denmark)

    Borkar, Nrupa Nitin; Holm, René; Yang, Mingshi

    2016-01-01

    .05) than after DLA-w/o administration, indicating that triglycerides and surfactants improved the oral absorption of DLA. Similarly, Cmax and AUC after dosing apomorphine-o/w were significantly higher (p≤0.05) than that of aqueous suspension. This suggested that lipids and lipolysis products possibly aided......In the present study, the differences in oral absorption of apomorphine and its diester prodrugs and the effect of lipid-based formulations on the absorption of apomorphine or its prodrugs were investigated. Apomorphine, dilauroyl apomorphine (DLA) and dipalmitoyl apomorphine (DPA) were orally...

  15. Spatiotemporal Control of Doxorubicin Delivery from “Stealth-Like” Prodrug Micelles

    Science.gov (United States)

    Kong, Li; Schneider, Gregory F.; Campbell, Frederick

    2017-01-01

    In the treatment of cancer, targeting of anticancer drugs to the tumor microenvironment is highly desirable. Not only does this imply accurate tumor targeting but also minimal drug release en route to the tumor and maximal drug release once there. Here we describe high-loading, “stealth-like” doxorubicin micelles as a pro-drug delivery system, which upon light activation, leads to burst-like doxorbicin release. Through this approach, we show precise spatiotemporal control of doxorubicin delivery to cells in vitro. PMID:28937592

  16. Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy

    DEFF Research Database (Denmark)

    Denmeade, Samuel R; Mhaka, Annastasiah M; Rosen, D Marc

    2012-01-01

    adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment...... of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host...

  17. Stability and in vitro metabolism of dipeptide model prodrugs with affinity for the oligopeptide transporter

    DEFF Research Database (Denmark)

    Lepist, E I; Kusk, T; Larsen, D H

    2000-01-01

    into the blood circulation and/or by its site of action. In these kinds of prodrugs the ester linkage may be broken by pH dependent and/or enzyme catalyzed hydrolysis. The objective of the present study was to investigate the degradation mechanism and rate of the model compounds Glu(OBzl)-Sar, D...... on buffer concentration, temperature, pH, and ionic strength. In biological media such as 80% human plasma, human gastric juice and intestinal fluid, and 10% rat jejunal homogenate at 37 degrees C, the half-lives were greater than 1 h except for the hydrolysis of Glu(OBzl)-Sar in 10% rat jejunal homogenate...

  18. Supplementation of chitosan alleviates high-fat diet-enhanced lipogenesis in rats via adenosine monophosphate (AMP)-activated protein kinase activation and inhibition of lipogenesis-associated genes.

    Science.gov (United States)

    Chiu, Chen-Yuan; Chan, Im-Lam; Yang, Tsung-Han; Liu, Shing-Hwa; Chiang, Meng-Tsan

    2015-03-25

    This study investigated the role of chitosan in lipogenesis in high-fat diet-induced obese rats. The lipogenesis-associated genes and their upstream regulatory proteins were explored. Diet supplementation of chitosan efficiently decreased the increased weights in body, livers, and adipose tissues in high-fat diet-fed rats. Chitosan supplementation significantly raised the lipolysis rate; attenuated the adipocyte hypertrophy, triglyceride accumulation, and lipoprotein lipase activity in epididymal adipose tissues; and decreased hepatic enzyme activities of lipid biosynthesis. Chitosan supplementation significantly activated adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and attenuated high-fat diet-induced protein expressions of lipogenic transcription factors (PPAR-γ and SREBP1c) in livers and adipose tissues. Moreover, chitosan supplementation significantly inhibited the expressions of downstream lipogenic genes (FAS, HMGCR, FATP1, and FABP4) in livers and adipose tissues of high-fat diet-fed rats. These results demonstrate for the first time that chitosan supplementation alleviates high-fat diet-enhanced lipogenesis in rats via AMPK activation and lipogenesis-associated gene inhibition.

  19. p38 mitogen-activated protein kinase (p38MAPK) upregulates catalase levels in response to low dose H2O2 treatment through enhancement of mRNA stability.

    Science.gov (United States)

    Sen, Prosenjit; Chakraborty, Prabir Kumar; Raha, Sanghamitra

    2005-08-15

    V79 fibroblasts were repetitively stressed through multiple exposures to a low dose (30 microM) H2O2 in culture for 4 weeks. Catalase activity, protein levels and mRNA levels increased markedly (5-6-fold) during this time and these augmentations were inhibited by the simultaneous presence of SB203580, an inhibitor of p38 mitogen-activated protein kinase (p38MAPK). p38MAPK became dually phosphorylated and ATF-2, a p38MAPK substrate also became increasingly phosphorylated over the repetitive stress period. Short interfering RNA that induced effective silencing of p38MAPK, was used to silence p38MAPK in V79 fibroblasts. Silencing of p38MAPK drastically hindered the elevation in catalase (protein and mRNA) levels observed after a single low dose (50 microM) of H2O. The rise in catalase mRNA levels induced by low concentration (single and multiple dose) H2O2 treatment was established to be unconnected with transcriptional upregulation but was brought forth primarily by an enhancement in catalase mRNA stability through the action of p38MAPK. Therefore, our data strongly indicate that activation of p38MAPK is a key controlling step in the upregulation of catalase levels by low dose H2O2 treatment.

  20. Rapid Osteogenic Enhancement of Stem Cells in Human Bone Marrow Using a Glycogen-Synthease-Kinase-3-Beta Inhibitor Improves Osteogenic Efficacy In Vitro and In Vivo.

    Science.gov (United States)

    Clough, Bret H; Zeitouni, Suzanne; Krause, Ulf; Chaput, Christopher D; Cross, Lauren M; Gaharwar, Akhilesh K; Gregory, Carl A

    2018-04-01

    Non-union defects of bone are a major problem in orthopedics, especially for patients with a low healing capacity. Fixation devices and osteoconductive materials are used to provide a stable environment for osteogenesis and an osteogenic component such as autologous human bone marrow (hBM) is then used, but robust bone formation is contingent on the healing capacity of the patients. A safe and rapid procedure for improvement of the osteoanabolic properties of hBM is, therefore, sought after in the field of orthopedics, especially if it can be performed within the temporal limitations of the surgical procedure, with minimal manipulation, and at point-of-care. One way to achieve this goal is to stimulate canonical Wingless (cWnt) signaling in bone marrow-resident human mesenchymal stem cells (hMSCs), the presumptive precursors of osteoblasts in bone marrow. Herein, we report that the effects of cWnt stimulation can be achieved by transient (1-2 hours) exposure of osteoprogenitors to the GSK3β-inhibitor (2'Z,3'E)-6-bromoindirubin-3'-oxime (BIO) at a concentration of 800 nM. Very-rapid-exposure-to-BIO (VRE-BIO) on either hMSCs or whole hBM resulted in the long-term establishment of an osteogenic phenotype associated with accelerated alkaline phosphatase activity and enhanced transcription of the master regulator of osteogenesis, Runx2. When VRE-BIO treated hBM was tested in a rat spinal fusion model, VRE-BIO caused the formation of a denser, stiffer, fusion mass as compared with vehicle treated hBM. Collectively, these data indicate that the VRE-BIO procedure may represent a rapid, safe, and point-of-care strategy for the osteogenic enhancement of autologous hBM for use in clinical orthopedic procedures. Stem Cells Translational Medicine 2018;7:342-353. © 2018 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  1. Apoptosis Signal-Regulating Kinase 1 Is Involved in Brain-Derived Neurotrophic Factor (BDNF)-Enhanced Cell Motility and Matrix Metalloproteinase 1 Expression in Human Chondrosarcoma Cells

    Science.gov (United States)

    Lin, Chih-Yang; Chang, Sunny Li-Yun; Fong, Yi-Chin; Hsu, Chin-Jung; Tang, Chih-Hsin

    2013-01-01

    Chondrosarcoma is the primary malignancy of bone that is characterized by a potent capacity to invade locally and cause distant metastasis, and is therefore associated with poor prognoses. Chondrosarcoma further shows a predilection for metastasis to the lungs. The brain-derived neurotrophic factor (BDNF) is a small molecule in the neurotrophin family of growth factors that is associated with the disease status and outcome of cancers. However, the effect of BDNF on cell motility in human chondrosarcoma cells is mostly unknown. Here, we found that human chondrosarcoma cell lines had significantly higher cell motility and BDNF expression compared to normal chondrocytes. We also found that BDNF increased cell motility and expression of matrix metalloproteinase-1 (MMP-1) in human chondrosarcoma cells. BDNF-mediated cell motility and MMP-1 up-regulation were attenuated by Trk inhibitor (K252a), ASK1 inhibitor (thioredoxin), JNK inhibitor (SP600125), and p38 inhibitor (SB203580). Furthermore, BDNF also promoted Sp1 activation. Our results indicate that BDNF enhances the migration and invasion activity of chondrosarcoma cells by increasing MMP-1 expression through a signal transduction pathway that involves the TrkB receptor, ASK1, JNK/p38, and Sp1. BDNF thus represents a promising new target for treating chondrosarcoma metastasis. PMID:23892595

  2. The secret life of kinases: functions beyond catalysis.

    LENUS (Irish Health Repository)

    Rauch, Jens

    2011-10-28

    Abstract Protein phosphorylation participates in the regulation of all fundamental biological processes, and protein kinases have been intensively studied. However, while the focus was on catalytic activities, accumulating evidence suggests that non-catalytic properties of protein kinases are essential, and in some cases even sufficient for their functions. These non-catalytic functions include the scaffolding of protein complexes, the competition for protein interactions, allosteric effects on other enzymes, subcellular targeting, and DNA binding. This rich repertoire often is used to coordinate phosphorylation events and enhance the specificity of substrate phosphorylation, but also can adopt functions that do not rely on kinase activity. Here, we discuss such kinase independent functions of protein and lipid kinases focussing on kinases that play a role in the regulation of cell proliferation, differentiation, apoptosis, and motility.

  3. MR Imaging Biomarkers to Monitor Early Response to Hypoxia-Activated Prodrug TH-302 in Pancreatic Cancer Xenografts.

    Directory of Open Access Journals (Sweden)

    Xiaomeng Zhang

    Full Text Available TH-302 is a hypoxia-activated prodrug known to activate selectively under the hypoxic conditions commonly found in solid tumors. It is currently being evaluated in clinical trials, including two trials in Pancreatic Ductal Adenocarcinomas (PDAC. The current study was undertaken to evaluate imaging biomarkers for prediction and response monitoring of TH-302 efficacy in xenograft models of PDAC. Dynamic contrast-enhanced (DCE and diffusion weighted (DW magnetic resonance imaging (MRI were used to monitor acute effects on tumor vasculature and cellularity, respectively. Three human PDAC xenografts with known differential responses to TH-302 were imaged prior to, and at 24 h and 48 hours following a single dose of TH-302 or vehicle to determine if imaging changes presaged changes in tumor volumes. DW-MRI was performed at five b-values to generate apparent diffusion coefficient of water (ADC maps. For DCE-MRI, a standard clinically available contrast reagent, Gd-DTPA, was used to determine blood flow into the tumor region of interest. TH-302 induced a dramatic decrease in the DCE transfer constant (Ktrans within 48 hours after treatment in the sensitive tumors, Hs766t and Mia PaCa-2, whereas TH-302 had no effect on the perfusion behavior of resistant SU.86.86 tumors. Tumor cellularity, estimated from ADC, was significantly increased 24 and 48 hours after treatment in Hs766t, but was not observed in the Mia PaCa-2 and SU.86.86 groups. Notably, growth inhibition of Hs766t was observed immediately (day 3 following initiation of treatment, but was not observed in MiaPaCa-2 tumors until 8 days after initiation of treatment. Based on these preclinical findings, DCE-MRI measures of vascular perfusion dynamics and ADC measures of cell density are suggested as potential TH-302 response biomarkers in clinical trials.

  4. Layer-by-layer nanoparticles co-loading gemcitabine and platinum (IV prodrugs for synergistic combination therapy of lung cancer

    Directory of Open Access Journals (Sweden)

    Zhang R

    2017-09-01

    Full Text Available Rongrong Zhang, Yun Ru, Yiping Gao, Jinyin Li, Shilong Mao Department of Pharmacy, Shanghai Xuhui District Central Hospital, Zhongshan Hospital Affiliated to Fudan University Xuhui Hospital, Shanghai, People’s Republic of China Purpose: Cisplatin plus gemcitabine (GEM is a standard regimen for the first-line treatment of advanced non-small cell lung cancer. The aim of this study was to prepare biocompatible and biodegradable polymeric prodrugs and construct nanoparticles (NPs with layer-by-layer (LbL technique. Methods: Platinum (Pt (IV complex with a carboxyl group was conjugated to the amino group of chitosan (CH, resulting in a CH-Pt conjugation with positive charge. GEM with amino group was conjugated to the carboxyl group of hyaluronic acid (HA, resulting in a HA-GEM conjugation with negative charge. Novel LbL NPs consisting of the CH-Pt core and the HA-GEM layer, named as HA-GEM/CH-Pt NPs, were constructed. The physicochemical properties of the HA-GEM/CH-Pt NPs were investigated. In vitro cytotoxicity against human non-small lung cancer cells (NCl-H460 cells was investigated, and in vivo antitumor efficiency was evaluated on mice bearing NCl-H460 cells xenografts. Results: HA-GEM/CH-Pt NPs have a size of about 187 nm, a zeta potential value of -21 mV and high drug encapsulation efficiency of 90%. The drug release of HA-GEM/CH-Pt NPs exhibited a sustained behavior. HA-GEM/CH-Pt NPs could significantly enhance in vitro cytotoxicity and in vivo antitumor effect against lung cancer animal model compared to the single-drug-loaded NPs and free drug solutions. Conclusion: The results demonstrated that the HA-GEM/CH-Pt NPs might be a promising system for the synergetic treatment of lung carcinoma. Keywords: lung cancer, combination chemotherapy, cisplatin, gemcitabine, layer-by-layer technology

  5. Melatonin, a potent agent in antioxidative defense: Actions as a natural food constituent, gastrointestinal factor, drug and prodrug

    Directory of Open Access Journals (Sweden)

    Pandi-Perumal SR

    2005-09-01

    Full Text Available Abstract Melatonin, originally discovered as a hormone of the pineal gland, is also produced in other organs and represents, additionally, a normal food constituent found in yeast and plant material, which can influence the level in the circulation. Compared to the pineal, the gastrointestinal tract contains several hundred times more melatonin, which can be released into the blood in response to food intake and stimuli by nutrients, especially tryptophan. Apart from its use as a commercial food additive, supraphysiological doses have been applied in medical trials and pure preparations are well tolerated by patients. Owing to its amphiphilicity, melatonin can enter any body fluid, cell or cell compartment. Its properties as an antioxidant agent are based on several, highly diverse effects. Apart from direct radical scavenging, it plays a role in upregulation of antioxidant and downregulation of prooxidant enzymes, and damage by free radicals can be reduced by its antiexcitatory actions, and presumably by contributions to appropriate internal circadian phasing, and by its improvement of mitochondrial metabolism, in terms of avoiding electron leakage and enhancing complex I and complex IV activities. Melatonin was shown to potentiate effects of other antioxidants, such as ascorbate and Trolox. Under physiological conditions, direct radical scavenging may only contribute to a minor extent to overall radical detoxification, although melatonin can eliminate several of them in scavenger cascades and potentiates the efficacy of antioxidant vitamins. Melatonin oxidation seems rather important for the production of other biologically active metabolites such as N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK and N1-acetyl-5-methoxykynuramine (AMK, which have been shown to also dispose of protective properties. Thus, melatonin may be regarded as a prodrug, too. AMK interacts with reactive oxygen and nitrogen species, conveys protection to mitochondria

  6. MR Imaging Biomarkers to Monitor Early Response to Hypoxia-Activated Prodrug TH-302 in Pancreatic Cancer Xenografts.

    Science.gov (United States)

    Zhang, Xiaomeng; Wojtkowiak, Jonathan W; Martinez, Gary V; Cornnell, Heather H; Hart, Charles P; Baker, Amanda F; Gillies, Robert

    2016-01-01

    TH-302 is a hypoxia-activated prodrug known to activate selectively under the hypoxic conditions commonly found in solid tumors. It is currently being evaluated in clinical trials, including two trials in Pancreatic Ductal Adenocarcinomas (PDAC). The current study was undertaken to evaluate imaging biomarkers for prediction and response monitoring of TH-302 efficacy in xenograft models of PDAC. Dynamic contrast-enhanced (DCE) and diffusion weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor vasculature and cellularity, respectively. Three human PDAC xenografts with known differential responses to TH-302 were imaged prior to, and at 24 h and 48 hours following a single dose of TH-302 or vehicle to determine if imaging changes presaged changes in tumor volumes. DW-MRI was performed at five b-values to generate apparent diffusion coefficient of water (ADC) maps. For DCE-MRI, a standard clinically available contrast reagent, Gd-DTPA, was used to determine blood flow into the tumor region of interest. TH-302 induced a dramatic decrease in the DCE transfer constant (Ktrans) within 48 hours after treatment in the sensitive tumors, Hs766t and Mia PaCa-2, whereas TH-302 had no effect on the perfusion behavior of resistant SU.86.86 tumors. Tumor cellularity, estimated from ADC, was significantly increased 24 and 48 hours after treatment in Hs766t, but was not observed in the Mia PaCa-2 and SU.86.86 groups. Notably, growth inhibition of Hs766t was observed immediately (day 3) following initiation of treatment, but was not observed in MiaPaCa-2 tumors until 8 days after initiation of treatment. Based on these preclinical findings, DCE-MRI measures of vascular perfusion dynamics and ADC measures of cell density are suggested as potential TH-302 response biomarkers in clinical trials.

  7. Pyruvate kinase blood test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003357.htm Pyruvate kinase blood test To use the sharing features on this page, ... energy when oxygen levels are low. How the Test is Performed A blood sample is needed. In the laboratory, white blood ...

  8. The nitric oxide prodrug JS-K and its structural analogues as cancer therapeutic agents.

    Science.gov (United States)

    Maciag, Anna E; Saavedra, Joseph E; Chakrapani, Harinath

    2009-09-01

    Nitric oxide (NO) prodrugs of the diazeniumdiolate class are routinely used as reliable sources of nitric oxide in chemical and biological laboratory settings. O(2)-(2,4-dinitrophenyl) diazeniumdiolates, which are derivatized forms of ionic diazeniumdiolates, have been found to show potent anti-proliferative activity in a variety of cancer cells, presumably through the effects of NO. One important member of this class of diazeniumdiolates, O(2)-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K), has shown promise as a novel cancer therapeutic agent in a number of animal models. This review describes the developments in chemical and biochemical characterization and structure-activity relationship of JS-K and its analogues. In addition, some molecular mechanistic insights into the observed anti-proliferative activity of JS-K are discussed. Finally, a structural motif is presented for O(2)-(aryl) diazeniumdiolate nitric oxide prodrugs that show potency comparable with that of JS-K.

  9. Mefenamic acid conjugates based on a hydrophilic biopolymer hydroxypropylcellulose: novel prodrug design, characterization and thermal analysis

    International Nuclear Information System (INIS)

    Hussain, M.A.; Kausar, R.; Amin, M.

    2015-01-01

    Macromolecular prodrugs (MPDs) of mefenamic acid were designed onto a cellulose ether derivative hydroxypropylcellulose (HPC) as ester conjugates. Fabrication of HPC-mefenamic acid conjugates was achieved by using p-toluenesulfonyl chloride as carboxylic acid (a functional group in drug) activator at 80 degree C for 24 h under nitrogen atmosphere. Reaction was preceded under homogeneous reaction conditions as HPC was dissolved before use in DMAc solvent. Imidazole was used as a base. Easy workup reactions resulted in good yields (55-65%) and degree of substitution (DS) of drug (0.37-0.99) onto HPC. The DS was calculated by acid-base titration after saponification and UV/Vis spectrophotometry after hydrolysis. DS by both of the methods was found in good agreement with each other. Aqueous and organic soluble novel prodrugs of mefenamic acid were purified and characterized by different spectroscopic and thermal analysis techniques. The initial, maximum and final degradation temperatures of HPC, mefenamic acid and HPC-mefenamic acid conjugates were drawn from thermogravimetric (TG) and derivative TG curves and compared to access relative thermal stability. The TG analysis has indicated that samples obtained were thermally more stable especially with increased stability of mefenamic acid in HPC-mefenamic acid conjugates. These novel MPDs of mefenamic acid (i.e., HPC-mefenamic acid conjugates) may have potential applications in pharmaceutically viable drug design due to wide range of solubility and extra thermal stability imparted after MPD formation. (author)

  10. A prodrug strategy based on chitosan for efficient intracellular anticancer drug delivery

    International Nuclear Information System (INIS)

    Chen, Cheng; Zhou, Jiang-Ling; Han, Xue; Song, Fei; Wang, Xiu-Li; Wang, Yu-Zhong

    2014-01-01

    Doxorubicin (DOX), one of the most widely used anticancer drugs, is restricted in clinical application due to its severe side effects and inefficient cellular uptake. To overcome the drawbacks, herein, an endosomal pH-activated prodrug was designed and fabricated by conjugating DOX with chitosan via an acid-cleavable hydrazone bond. The resulting DOX conjugates can self-assemble into nano-sized particles, which were very stable and presented no burst release of DOX at a neutral pH condition. Notably, the nanoparticles exhibited excellent cell uptake properties and a remarkable drug accumulation in tumor cells. Once internalized into the cells, moreover, DOX can be fast released from the nanoparticles, and the release mechanism changed from the anomalous transport at pH 7.4 to the combination pattern of diffusion- and erosion-controlled release at pH 6.0 or 5.0. The prodrugs showed obvious cytotoxicity for HeLa cells with fairly low IC 50 values, offering a new platform for targeted cancer therapy. (papers)

  11. Aspartic acid based nucleoside phosphoramidate prodrugs as potent inhibitors of hepatitis C virus replication.

    Science.gov (United States)

    Maiti, Munmun; Maiti, Mohitosh; Rozenski, Jef; De Jonghe, Steven; Herdewijn, Piet

    2015-05-14

    In view of a persistent threat to mankind, the development of nucleotide-based prodrugs against hepatitis C virus (HCV) is considered as a constant effort in many medicinal chemistry groups. In an attempt to identify novel nucleoside phosphoramidate analogues for improving the anti-HCV activity, we have explored, for the first time, aspartic acid (Asp) and iminodiacetic acid (IDA) esters as amidate counterparts by considering three 2'-C-methyl containing nucleosides, 2'-C-Me-cytidine, 2'-C-Me-uridine and 2'-C-Me-2'-fluoro-uridine. Synthesis of these analogues required protection for the vicinal diol functionality of the sugar moiety and the amino group of the cytidine nucleoside to regioselectively perform phosphorylation reaction at the 5'-hydroxyl group. Anti-HCV data demonstrate that the Asp-based phosphoramidates are ∼550 fold more potent than the parent nucleosides. The inhibitory activity of the Asp-ProTides was higher than the Ala-ProTides, suggesting that Asp would be a potential amino acid candidate to be considered for developing novel antiviral prodrugs.

  12. Anti-HIV therapy with AZT prodrugs: AZT phosphonate derivatives, current state and prospects.

    Science.gov (United States)

    Khandazhinskaya, Anastasiya; Matyugina, Elena; Shirokova, Elena

    2010-06-01

    AIDS, a disease caused by human immunodeficiency virus, was called 'plague of the twentieth century'. 3'-Azido-3'-deoxythymidine (AZT), the first compound approved for the treatment of HIV, is still a mandatory component of treatment schemes. However, its toxicity stimulated a search for new agents. This review presents the history and current state of the design of AZT prodrugs based on its phosphonate derivatives. Although every effort was made to include as many AZT structures bearing phosphonate residues and demonstrate the variety they offer, we also concentrated on the studies performed in our laboratory. Special attention was also paid to AZT 5'-H-phosphonate (phosphazide, Nikavir) approved in the Russian Federation as a drug for the prevention and treatment of HIV infection. The prodrug strategy applied to AZT phosphonate derivatives enriched chemistry, biology and medicine not only with new knowledge, methods and structures, but also with a new anti-HIV drug Nikavir. Currently, study of another phosphonate, AZT 5'-aminocarbonylphosphonate, is underway. Slow release of AZT following oral administration and penetration into cells, decreased toxicity and the lack of cumulative properties make the compounds of this group promising as extended-release forms of AZT.

  13. Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery.

    Science.gov (United States)

    Pan, Dipanjan; Pham, Christine T N; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

    2016-01-01

    Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a 'magic bullet' to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a 'Grail Quest' by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made 'made the turn' toward meaningful translational success. © 2015 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals, Inc.

  14. Smart activatable and traceable dual-prodrug for image-guided combination photodynamic and chemo-therapy.

    Science.gov (United States)

    Hu, Fang; Yuan, Youyong; Mao, Duo; Wu, Wenbo; Liu, Bin

    2017-11-01

    Activatable photosensitizers (PSs) and chemo-prodrugs are highly desirable for anti-cancer therapy to reduce systemic toxicity. However, it is difficult to integrate both together into a molecular probe for combination therapy due to the complexity of introducing PS, singlet oxygen quencher, chemo-drug, chemo-drug inhibitor and active linker at the same time. To realize activatable PS and chemo-prodrug combination therapy, we develop a smart therapeutic platform in which the chemo-prodrug serves as the singlet oxygen quencher for the PS. Specifically, the photosensitizing activity and fluorescence of the PS (TPEPY-SH) are blocked by the chemo-prodrug (Mitomycin C, MMC) in the probe. Meanwhile, the cytotoxicity of MMC is also inhibited by the electron-withdrawing acyl at the nitrogen position next to the linker. Upon glutathione activation, TPEPY-S-MMC can simultaneously release active PS and MMC for combination therapy. The restored fluorescence of TPEPY-SH is also used to report the activation for both PS and MMC as well as to guide the photodynamic therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Synthesis and properties of a new water-soluble prodrug of the adenosine A 2A receptor antagonist MSX-2.

    Science.gov (United States)

    Vollmann, Karl; Qurishi, Ramatullah; Hockemeyer, Jörg; Müller, Christa E

    2008-02-12

    The compound L-valine-3-{8-[(E)-2-[3-methoxyphenyl)ethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4) was synthesized as an amino acid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to be stable in artificial gastric acid, but readily cleaved by pig liver esterase.

  16. A MONOCLONAL ANTIBODY-BETA-GLUCURONIDASE CONJUGATE AS ACTIVATOR OF THE PRODRUG EPIRUBICIN-GLUCURONIDE FOR SPECIFIC TREATMENT OF CANCER

    NARCIS (Netherlands)

    Haisma, Hidde; BOVEN, E; VANMUIJEN, M; DEJONG, J; VANDERVIJGH, WJF; PINEDO, HM

    The anti-pan carcinoma monoclonal antibody (MAb) 323/A3, linked to E. coli-derived beta-glucuronidase (GUS) was used to study the tumour-site-selective activation of the prodrug Epirubicin-glucuronide (Epi-glu). Epi-glu was isolated from the urine of patients treated with Epirubicin (Epi) by

  17. A Prodrug Approach Involving In Situ Depot Formation to Achieve Localized and Sustained Action of Diclofenac After Joint Injection

    DEFF Research Database (Denmark)

    Thing, Mette; Agårdh, Li; Larsen, Susan

    2014-01-01

    Long-acting nonsteroidal anti-inflammatory drug formulations for intra-articular injection might be effective in the management of joint pain and inflammation associated sports injuries and osteoarthritis. In this study, a prodrug-based delivery system was evaluated. The synthesized diclofenac...

  18. Synthesis and biological properties of prodrugs of (S)-3-(adenin-9-yl)-2-(phosphonomethoxy)propanoic acid

    Czech Academy of Sciences Publication Activity Database

    Kaiser, Martin Maxmilian; Poštová Slavětínská, Lenka; Dračínský, Martin; Lee, Y. J.; Tian, Y.; Janeba, Zlatko

    2016-01-01

    Roč. 108, Jan 27 (2016), s. 374-380 ISSN 0223-5234 R&D Projects: GA MV VG20102015046 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * (S)-CPMEA * antiviral * HCV * prodrugs Subject RIV: CC - Organic Chemistry Impact factor: 4.519, year: 2016

  19. Design and synthesis of brain-targeted prodrugs of the glutamine antagonist 6-Diazo-5-oxo-L-norleucine

    Czech Academy of Sciences Publication Activity Database

    Tenora, Lukáš; Novotná, Kateřina; Monincová, Lenka; Jančařík, Andrej; Nedelcovych, M.; Alt, J.; Rais, R.; Slusher, B. S.; Majer, Pavel

    2017-01-01

    Roč. 284, Suppl 1 (2017), s. 344 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] Institutional support: RVO:61388963 Keywords : 6-Diazo-5-oxo-L-norleucine * prodrugs Subject RIV: CE - Biochemistry

  20. Design and synthesis of brain-targeted prodrugs of the glutamine antagonist 6-Diazo-5-oxo-L-norleucine

    Czech Academy of Sciences Publication Activity Database

    Tenora, Lukáš; Novotná, Kateřina; Monincová, Lenka; Jančařík, Andrej; Gadiano, A. J.; Dash, R.; Rais, R.; Alt, J.; Slusher, B. S.; Majer, Pavel

    2017-01-01

    Roč. 284, Suppl 1 (2017), s. 345 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] Institutional support: RVO:61388963 Keywords : 6-Diazo-5-oxo-L-norleucine * prodrugs Subject RIV: CE - Biochemistry

  1. Lipases as Tools in the Synthesis of Prodrugs from Racemic 9-(2,3-Dihydroxypropyl)adenine

    Czech Academy of Sciences Publication Activity Database

    Brabcová, Jana; Blažek, Jiří; Janská, Lucie; Krečmerová, Marcela; Zarevúcka, Marie

    2012-01-01

    Roč. 17, č. 12 (2012), s. 13813-13824 ISSN 1420-3049 Grant - others:AV ČR(CZ) M200551203 Institutional support: RVO:61388963 Keywords : lipase * transesterification * prodrug * immobilization of enzymes Subject RIV: CC - Organic Chemistry Impact factor: 2.428, year: 2012

  2. Amidate Prodrugs of 9-[2-(Phosphonomethoxy)Ethyl]Adenine as Inhibitors of Adenylate Cyclase Toxin from Bordetella pertussis

    Czech Academy of Sciences Publication Activity Database

    Šmídková, Markéta; Dvořáková, Alexandra; Tloušťová, Eva; Česnek, Michal; Janeba, Zlatko; Mertlíková-Kaiserová, Helena

    2014-01-01

    Roč. 58, č. 2 (2014), s. 664-671 ISSN 0066-4804 R&D Projects: GA MV VG20102015046 Grant - others:OPPC(XE) CZ.2.16/3.1.00/24016 Institutional support: RVO:61388963 Keywords : Bordetella pertussis * adenylate cyclase toxin * ACT * inhibitors * PMEA * amidate prodrugs Subject RIV: CC - Organic Chemistry Impact factor: 4.476, year: 2014

  3. Determination of dopaminergic prodrugs by high-performance liquid chromatography followed by post-column ion-pair extraction

    NARCIS (Netherlands)

    Haas, M; Moolenaar, Frits; Kluppel, A.C A; Dijkstra, D.; Meijer, D.K F; de Zeeuw, D

    1997-01-01

    One possibility to optimize the therapeutic application of dopaminergic compounds with a catechol function is the reversible protection of this moiety using a prodrug approach. Important features in this respect are a proper chemical stability in the gastrointestinal tract, an adequate release rate

  4. Synthesis and Properties of a New Water-Soluble Prodrug of the Adenosine A2A Receptor Antagonist MSX-2

    Directory of Open Access Journals (Sweden)

    Christa E. Müller

    2008-02-01

    Full Text Available The compound L-valine-3-{8-[(E-2-[3-methoxyphenylethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4 was synthesized as an aminoacid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to bestable in artificial gastric acid, but readily cleaved by pig liver esterase.

  5. Model prodrugs for the intestinal peptide transporter. a synthetic approach for coupling of hydroxy-containing compounds to dieptides

    DEFF Research Database (Denmark)

    Friedrichsen, G; Nielsen, Carsten Uhd; Steffansen, Bente

    2001-01-01

    The human peptide transporter, hPepT1, situated in the small intestine, may be exploited to increase absorption of drugs or model drugs by attaching them to a dipeptide, which is recognised by hPepT1. A synthetic protocol for this kind of model prodrugs was developed, in which model drugs...

  6. Targeting (cellular) lysosomal acid ceramidase by B13: design, synthesis and evaluation of novel DMG-B13 ester prodrugs.

    Science.gov (United States)

    Bai, Aiping; Szulc, Zdzislaw M; Bielawski, Jacek; Pierce, Jason S; Rembiesa, Barbara; Terzieva, Silva; Mao, Cungui; Xu, Ruijuan; Wu, Bill; Clarke, Christopher J; Newcomb, Benjamin; Liu, Xiang; Norris, James; Hannun, Yusuf A; Bielawska, Alicja

    2014-12-15

    Acid ceramidase (ACDase) is being recognized as a therapeutic target for cancer. B13 represents a moderate inhibitor of ACDase. The present study concentrates on the lysosomal targeting of B13 via its N,N-dimethylglycine (DMG) esters (DMG-B13 prodrugs). Novel analogs, the isomeric mono-DMG-B13, LCL522 (3-O-DMG-B13·HCl) and LCL596 (1-O-DMG-B13·HCl) and di-DMG-B13, LCL521 (1,3-O, O-DMG-B13·2HCl) conjugates, were designed and synthesized through N,N-dimethyl glycine (DMG) esterification of the hydroxyl groups of B13. In MCF7 cells, DMG-B13 prodrugs were efficiently metabolized to B13. The early inhibitory effect of DMG-B13 prodrugs on cellular ceramidases was ACDase specific by their lysosomal targeting. The corresponding dramatic decrease of cellular Sph (80-97% Control/1h) by DMG-B13 prodrugs was mainly from the inhibition of the lysosomal ACDase. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. The enzymatic degradation and transport of leucine-enkephalin and 4-imidazolidinone enkephalin prodrugs at the blood-brain barrier

    DEFF Research Database (Denmark)

    Lund, L.; Bak, A.; Friis, G.J.

    1998-01-01

    In this study, the stability in and transport across a cell culture model of the blood-brain barrier (BBB) is investigated for leucine-enkephalin (Leu-enkephalin) and four 4-imidazolidinone prodrugs of Leu-enkephalin. The results show that Leu-enkephalin is degraded in the cell culture model...

  8. Enhanced

    Directory of Open Access Journals (Sweden)

    Martin I. Bayala

    2014-06-01

    Full Text Available Land Surface Temperature (LST is a key parameter in the energy balance model. However, the spatial resolution of the retrieved LST from sensors with high temporal resolution is not accurate enough to be used in local-scale studies. To explore the LST–Normalised Difference Vegetation Index relationship potential and obtain thermal images with high spatial resolution, six enhanced image sharpening techniques were assessed: the disaggregation procedure for radiometric surface temperatures (TsHARP, the Dry Edge Quadratic Function, the Difference of Edges (Ts∗DL and three models supported by the relationship of surface temperature and water stress of vegetation (Normalised Difference Water Index, Normalised Difference Infrared Index and Soil wetness index. Energy Balance Station data and in situ measurements were used to validate the enhanced LST images over a mixed agricultural landscape in the sub-humid Pampean Region of Argentina (PRA, during 2006–2010. Landsat Thematic Mapper (TM and Moderate Resolution Imaging Spectroradiometer (EOS-MODIS thermal datasets were assessed for different spatial resolutions (e.g., 960, 720 and 240 m and the performances were compared with global and local TsHARP procedures. Results suggest that the Ts∗DL technique is the most adequate for simulating LST to high spatial resolution over the heterogeneous landscape of a sub-humid region, showing an average root mean square error of less than 1 K.

  9. Modification of concomitant drug release from oil vehicles using drug-prodrug combinations to achieve sustained balanced analgesia after joint installation

    DEFF Research Database (Denmark)

    Thing, Mette; Jensen, Sabrine Smedegaard; Larsen, Claus Selch

    2012-01-01

    Intra-articular injection of two drugs in a sustained drug delivery system combining the use of lipophilic solution with the prodrug approach may provide efficient and prolonged postoperative pain treatment after arthroscopic procedures. In the present study, the concomitant release of N...... using buffer. In both release models, the use of ropivacaine-prodrug combination provided concomitant release from the oil into synovial fluid with ropivacaine being released faster than naproxen. The use of lipophilic prodrugs that are converted fast to the parent drug in synovial fluid seems...

  10. Cargo-free nano-medicine with pH-sensitivity for co-delivery of DOX conjugated prodrug with SN38 to synergistically eradicate breast cancer stem cells.

    Science.gov (United States)

    Sun, Na; Zhao, Chenyang; Cheng, Rui; Liu, Zerong; Li, Xian; Lu, Axin; Tian, Zhongmin; Yang, Zhe

    2018-06-20

    Due to their abilities of transforming into bulk cancer cells and resistance to radiotherapy and chemotherapy, cancer stem cells (CSCs) are currently considered as a major obstacle for cancer treatment. Application of multiple drugs using nano-carriers is a promising approach to simultaneously eliminate non-cancer stem cells (non-CSCs) and CSCs. Herein, to employ the advantages of nano-medicine while avoiding new excipients, pH-responsive pro-drug (PEG-CH=N-DOX) was employed as the surfactant to fabricate cargo-free nano-medicine for co-delivery of DOX conjugated prodrug with SN38 to synergistically eradicate breast cancer stem cells (bCSCs) and non-bCSCs. Through the intermolecular interaction between DOX and SN38, PEG-CH=N-DOX and SN38 were assembled together to form a stable nano-medicine. This nano-medicine not only dramatically enhanced drug accumulation efficiency at the tumor site, but also effectively eliminated bCSCs and non-bCSCs, which resulted in achieving a superior in vivo tumor inhibition activity. Additionally, the biosafety of this nano-medicine was systematically studied through immunohistochemistry, blood bio-chemistry assay, blood routine examination and metabolomics. The results revealed that this nano-medicine significantly reduced the adverse effects of DOX and SN38. Therefore, this simple yet efficient nano-medicine provided a promising strategy for future clinical applications.

  11. Developing a novel dual PI3K–mTOR inhibitor from the prodrug of a metabolite

    Directory of Open Access Journals (Sweden)

    Zhou Y

    2017-10-01

    Full Text Available Yan Zhou,1,2 Genyan Zhang,2 Feng Wang,2 Jin Wang,2 Yanwei Ding,2 Xinyu Li,2 Chongtie Shi,2 Jiakui Li,2 Chengkon Shih,2 Song You1 1The School of Life Science and Biopharmaceutical, Shenyang Pharmaceutical University, Shenyang, 2Department of Project Management, Medicinal Chemistry, Pharmacology, Drug Metabolism, and Pharmacokinetics, Toxicology, Xuanzhu Pharma, Jinan, China Abstract: This study presents a process of developing a novel PI3K–mTOR inhibitor through the prodrug of a metabolite. The lead compound (compound 1 was identified with similar efficacy as that of NVP-BEZ235 in a tumor xenograft model, but the exposure of compound 1 was much lower than that of NVP-BEZ235. After reanalysis of the blood sample, a major metabolite (compound 2 was identified. Compound 2 exerted similar in vitro activity as compound 1, which indicated that compound 2 was an active metabolite and that the in vivo efficacy in the animal model came from compound 2 instead of compound 1. However, compound 1 was metabolized into compound 2 predominantly in the liver microsomes of mouse, but not in the liver microsomes of rat, dog, or human. In order to translate the efficacy in the animal model into clinical development or predict the pharmacokinetic/pharmacodynamic parameters in the clinical study using a preclinical model, we developed the metabolite (compound 2 instead of compound 1. Due to the low bioavailability of compound 2, its prodrug (compound 3 was designed and synthesized to improve the solubility. The prodrug was quickly converted to compound 2 through both intravenous and oral administrations. Because the prodrug (compound 3 did not improve the oral exposure of compound 2, developing compound 3 as an intravenous drug was considered by our team, and the latest results will be reported in the future. Keywords: PI3K, mTOR, NVP-BEZ235, prodrug, metabolite, antitumor

  12. Specific inhibition of Wee1 kinase and Rad51 recombinase: A strategy to enhance the sensitivity of leukemic T-cells to ionizing radiation-induced DNA double-strand breaks

    International Nuclear Information System (INIS)

    Havelek, Radim; Cmielova, Jana; Kralovec, Karel; Bruckova, Lenka; Bilkova, Zuzana; Fousova, Ivana; Sinkorova, Zuzana; Vavrova, Jirina; Rezacova, Martina

    2014-01-01

    Highlights: • Pre-treatment with the inhibitors increased the sensitivity of Jurkat cells to irradiation. • Combining both inhibitors together resulted in a G2 cell cycle arrest abrogation in Jurkat. • Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. • Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction in MOLT-4 cells. • When dosed together, the combination decreased MOLT-4 cell survival. - Abstract: Present-day oncology sees at least two-thirds of cancer patients receiving radiation therapy as a part of their anticancer treatment. The objectives of the current study were to investigate the effects of the small molecule inhibitors of Wee1 kinase II (681641) and Rad51 (RI-1) on cell cycle progression, DNA double-strand breaks repair and apoptosis following ionizing radiation exposure in human leukemic T-cells Jurkat and MOLT-4. Pre-treatment with the Wee1 681641 or Rad51 RI-1 inhibitor alone increased the sensitivity of Jurkat cells to irradiation, however combining both inhibitors together resulted in a further enhancement of apoptosis. Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. MOLT-4 cells were less affected by inhibitors application prior to ionizing radiation exposure. Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction; however Wee1 681641 increased ionizing radiation-induced cell death in MOLT-4 cells

  13. Fabrication of Hyperbranched Block-Statistical Copolymer-Based Prodrug with Dual Sensitivities for Controlled Release.

    Science.gov (United States)

    Zheng, Luping; Wang, Yunfei; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Ji, Xiangling; Wei, Hua

    2018-01-17

    Dendrimer with hyperbranched structure and multivalent surface is regarded as one of the most promising candidates close to the ideal drug delivery systems, but the clinical translation and scale-up production of dendrimer has been hampered significantly by the synthetic difficulties. Therefore, there is considerable scope for the development of novel hyperbranched polymer that can not only address the drawbacks of dendrimer but maintain its advantages. The reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP) technique has enabled facile preparation of segmented hyperbranched polymer (SHP) by using chain transfer monomer (CTM)-based double-head agent during the past decade. Meanwhile, the design and development of block-statistical copolymers has been proven in our recent studies to be a simple yet effective way to address the extracellular stability vs intracellular high delivery efficacy dilemma. To integrate the advantages of both hyperbranched and block-statistical structures, we herein reported the fabrication of hyperbranched block-statistical copolymer-based prodrug with pH and reduction dual sensitivities using RAFT-SCVP and post-polymerization click coupling. The external homo oligo(ethylene glycol methyl ether methacrylate) (OEGMA) block provides sufficient extracellularly colloidal stability for the nanocarriers by steric hindrance, and the interior OEGMA units incorporated by the statistical copolymerization promote intracellular drug release by facilitating the permeation of GSH and H + for the cleavage of the reduction-responsive disulfide bond and pH-liable carbonate link as well as weakening the hydrophobic encapsulation of drug molecules. The delivery efficacy of the target hyperbranched block-statistical copolymer-based prodrug was evaluated in terms of in vitro drug release and cytotoxicity studies, which confirms both acidic pH and reduction-triggered drug release for inhibiting proliferation of He

  14. Identification of MicroRNA-124 as a Major Regulator of Enhanced Endothelial Cell Glycolysis in Pulmonary Arterial Hypertension via PTBP1 (Polypyrimidine Tract Binding Protein) and Pyruvate Kinase M2.

    Science.gov (United States)

    Caruso, Paola; Dunmore, Benjamin J; Schlosser, Kenny; Schoors, Sandra; Dos Santos, Claudia; Perez-Iratxeta, Carol; Lavoie, Jessie R; Zhang, Hui; Long, Lu; Flockton, Amanda R; Frid, Maria G; Upton, Paul D; D'Alessandro, Angelo; Hadinnapola, Charaka; Kiskin, Fedir N; Taha, Mohamad; Hurst, Liam A; Ormiston, Mark L; Hata, Akiko; Stenmark, Kurt R; Carmeliet, Peter; Stewart, Duncan J; Morrell, Nicholas W

    2017-12-19

    Pulmonary arterial hypertension (PAH) is characterized by abnormal growth and enhanced glycolysis of pulmonary artery endothelial cells. However, the mechanisms underlying alterations in energy production have not been identified. Here, we examined the miRNA and proteomic profiles of blood outgrowth endothelial cells (BOECs) from patients with heritable PAH caused by mutations in the bone morphogenetic protein receptor type 2 ( BMPR2 ) gene and patients with idiopathic PAH to determine mechanisms underlying abnormal endothelial glycolysis. We hypothesized that in BOECs from patients with PAH, the downregulation of microRNA-124 (miR-124), determined with a tiered systems biology approach, is responsible for increased expression of the splicing factor PTBP1 (polypyrimidine tract binding protein), resulting in alternative splicing of pyruvate kinase muscle isoforms 1 and 2 (PKM1 and 2) and consequently increased PKM2 expression. We questioned whether this alternative regulation plays a critical role in the hyperglycolytic phenotype of PAH endothelial cells. Heritable PAH and idiopathic PAH BOECs recapitulated the metabolic abnormalities observed in pulmonary artery endothelial cells from patients with idiopathic PAH, confirming a switch from oxidative phosphorylation to aerobic glycolysis. Overexpression of miR-124 or siRNA silencing of PTPB1 restored normal proliferation and glycolysis in heritable PAH BOECs, corrected the dysregulation of glycolytic genes and lactate production, and partially restored mitochondrial respiration. BMPR2 knockdown in control BOECs reduced the expression of miR-124, increased PTPB1 , and enhanced glycolysis. Moreover, we observed reduced miR-124, increased PTPB1 and PKM2 expression, and significant dysregulation of glycolytic genes in the rat SUGEN-hypoxia model of severe PAH, characterized by reduced BMPR2 expression and endothelial hyperproliferation, supporting the relevance of this mechanism in vivo. Pulmonary vascular and

  15. Imaging biomarkers to monitor response to the hypoxia-activated prodrug TH-302 in the MiaPaCa2 flank xenograft model.

    Science.gov (United States)

    Cárdenas-Rodríguez, Julio; Li, Yuguo; Galons, Jean-Philippe; Cornnell, Heather; Gillies, Robert J; Pagel, Mark D; Baker, Amanda F

    2012-09-01

    TH-302, a hypoxia-activated anticancer prodrug, was evaluated for antitumor activity and changes in dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) in a mouse model of pancreatic cancer. TH-302 monotherapy resulted in a significant delay in tumor growth compared to vehicle-treated controls. TH-302 treatment was also associated with a significant decrease in the volume transfer constant (K(trans)) compared to vehicle-treated controls 1 day following the first dose measured using DCE-MRI. This early decrease in K(trans) following the first dose as measured is consistent with selective killing of the hypoxic fraction of cells which are associated with enhanced expression of hypoxia inducible transcription factor-1 alpha that regulates expression of permeability and perfusion factors including vascular endothelial growth factor-A. No changes were observed in DW-MRI following treatment with TH-302, which may indicate that this technique is not sensitive enough to detect changes in small hypoxic fractions of the tumor targeted by TH-302. These results suggest that changes in tumor permeability and/or perfusion may be an early imaging biomarker for response to TH-302 therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Radiochemotherapy of hepatocarcinoma via lentivirus-mediated transfer of human sodium iodide symporter gene and herpes simplex virus thymidine kinase gene

    Energy Technology Data Exchange (ETDEWEB)

    Chen Libo, E-mail: libochen888@hotmail.com [Department of Nuclear Medicine, Shanghai Sixth People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Guo Guoying [Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Liu Tianjing; Guo Lihe [Division of Biochemistry and Cell Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031 (China); Zhu Ruisen [Department of Nuclear Medicine, Shanghai Sixth People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China)

    2011-07-15

    Herpes simplex virus thymidine kinase (HSV-TK) gene/ganciclovir (GCV) system has been widely used as a traditional gene therapy modality, and the sodium/iodide symporter gene (NIS) has been found to be a novel therapeutic gene. Since the therapeutic effects of radioiodine therapy or prodrug chemotherapy on cancers following NIS or HSV-TK gene transfer need to be enhanced, this study was designed to investigate the feasibility of radiochemotherapy for hepatocarcinoma via coexpression of NIS gene and HSV-TK gene. Methods: HepG2 cells were stably transfected with NIS, TK and GFP gene via recombinant lentiviral vector and named HepG2/NTG. Gene expression was examined by reverse transcriptase polymerase chain reaction, fluorescence imaging and iodide uptake. The therapeutic effects were assessed by MTT assay and clonogenic assay. Results: HepG2/NTG cells concentrated {sup 125}I{sup -} up to 76-fold higher than the wild-type cells within 20 min, and the efflux happened with a T{sub 1/2eff} of less than 10 min. The iodide uptake in HepG2/NTG cells was specifically inhibited by sodium perchlorate. Dose-dependent toxicity to HepG2/NTG cells by either GCV or {sup 131}I was revealed by clonogenic assay and MTT assay, respectively. The survival rate of HepG2/NTG cells decreased to 49.7%{+-}2.5%, 43.4%{+-}2.8% and 8.6%{+-}1.2% after exposure to {sup 131}I, GCV and combined therapy, respectively. Conclusion: We demonstrate that radiochemotherapy of hepatocarcinoma via lentiviral-mediated coexpression of NIS gene and HSV-TK gene leads to stronger killing effect than single treatment, and in vivo studies are needed to verify these findings.

  17. Radiochemotherapy of hepatocarcinoma via lentivirus-mediated transfer of human sodium iodide symporter gene and herpes simplex virus thymidine kinase gene

    International Nuclear Information System (INIS)

    Chen Libo; Guo Guoying; Liu Tianjing; Guo Lihe; Zhu Ruisen

    2011-01-01

    Herpes simplex virus thymidine kinase (HSV-TK) gene/ganciclovir (GCV) system has been widely used as a traditional gene therapy modality, and the sodium/iodide symporter gene (NIS) has been found to be a novel therapeutic gene. Since the therapeutic effects of radioiodine therapy or prodrug chemotherapy on cancers following NIS or HSV-TK gene transfer need to be enhanced, this study was designed to investigate the feasibility of radiochemotherapy for hepatocarcinoma via coexpression of NIS gene and HSV-TK gene. Methods: HepG2 cells were stably transfected with NIS, TK and GFP gene via recombinant lentiviral vector and named HepG2/NTG. Gene expression was examined by reverse transcriptase polymerase chain reaction, fluorescence imaging and iodide uptake. The therapeutic effects were assessed by MTT assay and clonogenic assay. Results: HepG2/NTG cells concentrated 125 I - up to 76-fold higher than the wild-type cells within 20 min, and the efflux happened with a T 1/2eff of less than 10 min. The iodide uptake in HepG2/NTG cells was specifically inhibited by sodium perchlorate. Dose-dependent toxicity to HepG2/NTG cells by either GCV or 131 I was revealed by clonogenic assay and MTT assay, respectively. The survival rate of HepG2/NTG cells decreased to 49.7%±2.5%, 43.4%±2.8% and 8.6%±1.2% after exposure to 131 I, GCV and combined therapy, respectively. Conclusion: We demonstrate that radiochemotherapy of hepatocarcinoma via lentiviral-mediated coexpression of NIS gene and HSV-TK gene leads to stronger killing effect than single treatment, and in vivo studies are needed to verify these findings.

  18. Phosphorylation of the Yeast Choline Kinase by Protein Kinase C

    Science.gov (United States)

    Choi, Mal-Gi; Kurnov, Vladlen; Kersting, Michael C.; Sreenivas, Avula; Carman, George M.

    2005-01-01

    The Saccharomyces cerevisiae CKI1-encoded choline kinase catalyzes the committed step in phosphatidylcholine synthesis via the Kennedy pathway. The enzyme is phosphorylated on multiple serine residues, and some of this phosphorylation is mediated by protein kinase A. In this work, we examined the hypothesis that choline kinase is also phosphorylated by protein kinase C. Using choline kinase as a substrate, protein kinase C activity was dose- and time-dependent, and dependent on the concentrations of choline kinase (Km = 27 μg/ml) and ATP (Km = 15 μM). This phosphorylation, which occurred on a serine residue, was accompanied by a 1.6-fold stimulation of choline kinase activity. The synthetic peptide SRSSS25QRRHS (Vmax/Km = 17.5 mM-1 μmol min-1 mg-1) that contains the protein kinase C motif for Ser25 was a substrate for protein kinase C. A Ser25 to Ala (S25A) mutation in choline kinase resulted in a 60% decrease in protein kinase C phosphorylation of the enzyme. Phosphopeptide mapping analysis of the S25A mutant enzyme confirmed that Ser25 was a protein kinase C target site. In vivo, the S25A mutation correlated with a decrease (55%) in phosphatidylcholine synthesis via the Kennedy pathway whereas an S25D phosphorylation site mimic correlated with an increase (44%) in phosphatidylcholine synthesis. Whereas the S25A (protein kinase C site) mutation did not affect the phosphorylation of choline kinase by protein kinase A, the S30A (protein kinase A site) mutation caused a 46% reduction in enzyme phosphorylation by protein kinase C. A choline kinase synthetic peptide (SQRRHS30LTRQ) containing Ser30 was a substrate (Vmax/Km = 3.0 mM−1 μmol min−1 mg−1) for protein kinase C. Comparison of phosphopeptide maps of the wild type and S30A mutant choline kinase enzymes phosphorylated by protein kinase C confirmed that Ser30 was also a target site for protein kinase C. PMID:15919656

  19. Enterococcus faecalis phosphomevalonate kinase

    Science.gov (United States)

    Doun, Stephanie S.; Burgner, John W.; Briggs, Scott D.; Rodwell, Victor W.

    2005-01-01

    The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram-positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic DNA and the polymerase chain reaction were used to clone DNA thought to encode phosphomevalonate kinase into pET28b(+). Double-stranded DNA sequencing verified the sequence of the recombinant gene. The encoded N-terminal hexahistidine-tagged protein was expressed in Escherichia coli with induction by isopropylthiogalactoside and purified by Ni++ affinity chromatography, yield 20 mg protein per liter. Analysis of the purified protein by MALDI-TOF mass spectrometry established it as E. faecalis phosphomevalonate kinase. Analytical ultracentrifugation revealed that the kinase exists in solution primarily as a dimer. Assay for phosphomevalonate kinase activity used pyruvate kinase and lactate dehydrogenase to couple the formation of ADP to the oxidation of NADH. Optimal activity occurred at pH 8.0 and at 37°C. The activation energy was ~5.6 kcal/mol. Activity with Mn++, the preferred cation, was optimal at about 4 mM. Relative rates using different phosphoryl donors were 100 (ATP), 3.6 (GTP), 1.6 (TTP), and 0.4 (CTP). Km values were 0.17 mM for ATP and 0.19 mM for (R,S)-5-phosphomevalonate. The specific activity of the purified enzyme was 3.9 μmol substrate converted per minute per milligram protein. Applications to an immobilized enzyme bioreactor and to drug screening and design are discussed. PMID:15802646

  20. From Phosphosites to Kinases

    DEFF Research Database (Denmark)

    Munk, Stephanie; Refsgaard, Jan C; Olsen, Jesper V

    2016-01-01

    Kinases play a pivotal role in propagating the phosphorylation-mediated signaling networks in living cells. With the overwhelming quantities of phosphoproteomics data being generated, the number of identified phosphorylation sites (phosphosites) is ever increasing. Often, proteomics investigations...... sequence motifs, mostly based on large scale in vivo and in vitro experiments. The context of the kinase and the phosphorylated proteins in a biological system is equally important for predicting association between the enzymes and substrates, an aspect that is also being tackled with available...

  1. Solid lipid nanoparticles by coacervation loaded with a methotrexate prodrug: preliminary study for glioma treatment.

    Science.gov (United States)

    Battaglia, Luigi; Muntoni, Elisabetta; Chirio, Daniela; Peira, Elena; Annovazzi, Laura; Schiffer, Davide; Mellai, Marta; Riganti, Chiara; Salaroglio, Iris Chiara; Lanotte, Michele; Panciani, Pierpaolo; Capucchio, Maria Teresa; Valazza, Alberto; Biasibetti, Elena; Gallarate, Marina

    2017-03-01

    Methotrexate-loaded biocompatible nanoparticles were tested for preliminary efficacy in glioma treatment. Behenic acid nanoparticles, prepared by the coacervation method, were loaded with the ester prodrug didodecylmethotrexate, which was previously tested in vitro against glioblastoma human primary cultures. Nanoparticle conjugation with an ApoE mimicking chimera peptide was performed to obtain active targeting to the brain. Biodistribution studies in healthy rats assessed the superiority of ApoE-conjugated formulation, which was tested on an F98/Fischer glioma model. Differences were observed in tumor growth rate (measured by MRI) between control and treated rats. In vitro tests on F98 cultured cells assessed their susceptibility to treatment, with consequent apoptosis, and allowed us to explain the apoptosis observed in glioma models.

  2. Discovery of an L-alanine ester prodrug of the Hsp90 inhibitor, MPC-3100.

    Science.gov (United States)

    Kim, Se-Ho; Tangallapally, Rajendra; Kim, In Chul; Trovato, Richard; Parker, Daniel; Patton, J Scott; Reeves, Leslie; Bradford, Chad; Wettstein, Daniel; Baichwal, Vijay; Papac, Damon; Bajji, Ashok; Carlson, Robert; Yager, Kraig M

    2015-11-15

    Various types of Hsp90 inhibitors have been and continue to undergo clinical investigation. One development candidate is the purine-based, synthetic Hsp90 inhibitor 1 (MPC-3100), which successfully completed a phase I clinical study. However, further clinical development of 1 was hindered by poor solubility and consequent formulation issues and promoted development of a more water soluble prodrug. Towards this end, numerous pro-moieties were explored in vitro and in vivo. These studies resulted in identification of L-alanine ester mesylate, 2i (MPC-0767), which exhibited improved aqueous solubility, adequate chemical stability, and rapid bioconversion without the need for solubilizing excipients. Based on improved physical characteristics and favorable PK and PD profiles, 2i mesylate was selected for further development. A convergent, scalable, chromatography-free synthesis for 2i mesylate was developed to support further clinical evaluation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy.

    Science.gov (United States)

    Denmeade, Samuel R; Mhaka, Annastasiah M; Rosen, D Marc; Brennen, W Nathaniel; Dalrymple, Susan; Dach, Ingrid; Olesen, Claus; Gurel, Bora; Demarzo, Angelo M; Wilding, George; Carducci, Michael A; Dionne, Craig A; Møller, Jesper V; Nissen, Poul; Christensen, S Brøgger; Isaacs, John T

    2012-06-27

    Heterogeneous expression of drug target proteins within tumor sites is a major mechanism of resistance to anticancer therapies. We describe a strategy to selectively inhibit, within tumor sites, the function of a critical intracellular protein, the sarcoplasmic/endoplasmic reticulum calcium adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host. On the basis of these data, a phase 1 dose-escalation clinical trial has been initiated with G202 in patients with advanced cancer.

  4. Syntheses of prodrug-type phosphotriester oligonucleotides responsive to intracellular reducing environment for improvement of cell membrane permeability and nuclease resistance.

    Science.gov (United States)

    Hayashi, Junsuke; Samezawa, Yusuke; Ochi, Yosuke; Wada, Shun-Ichi; Urata, Hidehito

    2017-07-15

    We synthesized prodrug-type phosphotriester (PTE) oligonucleotides containing the six-membered cyclic disulfide moiety by using phosphoramidite chemistry. Prodrug-type oligonucleotides named "Reducing-Environment-Dependent Uncatalyzed Chemical Transforming (REDUCT) PTE oligonucleotides" were converted into natural oligonucleotides under cytosol-mimetic reductive condition. Furthermore, the REDUCT PTE oligonucleotides were robust to nuclease digestion and exhibited good cell membrane permeability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Identification of oxidized protein hydrolase as a potential prodrug target in prostate cancer

    International Nuclear Information System (INIS)

    McGoldrick, Christopher A; Jiang, Yu-Lin; Paromov, Victor; Brannon, Marianne; Krishnan, Koyamangalath; Stone, William L

    2014-01-01

    Esterases are often overexpressed in cancer cells and can have chiral specificities different from that of the corresponding normal tissues. For this reason, ester prodrugs could be a promising approach in chemotherapy. In this study, we focused on the identification and characterization of differentially expressed esterases between non-tumorigenic and tumorigenic prostate epithelial cells. Cellular lysates from LNCaP, DU 145, and PC3 prostate cancer cell lines, tumorigenic RWPE-2 prostate epithelial cells, and non-tumorigenic RWPE-1 prostate epithelial cells were separated by native polyacrylamide gel electrophoresis (n-PAGE) and the esterase activity bands visualized using α-naphthyl acetate or α-naphthyl-N-acetylalaninate (ANAA) chiral esters and Fast Blue RR salt. The esterases were identified using nanospray LC/MS-MS tandem mass spectrometry and confirmed by Western blotting, native electroblotting, inhibition assays, and activity towards a known specific substrate. The serine protease/esterase oxidized protein hydrolase (OPH) was overexpressed in COS-7 cells to verify our results. The major esterase observed with the ANAA substrates within the n-PAGE activity bands was identified as OPH. OPH (EC 3.4.19.1) is a serine protease/esterase and a member of the prolyl oligopeptidase family. We found that LNCaP lysates contained approximately 40% more OPH compared to RWPE-1 lysates. RWPE-2, DU145 and PC3 cell lysates had similar levels of OPH activity. OPH within all of the cell lysates tested had a chiral preference for the S-isomer of ANAA. LNCaP cells were stained more intensely with ANAA substrates than RWPE-1 cells and COS-7 cells overexpressing OPH were found to have a higher activity towards the ANAA and AcApNA than parent COS-7 cells. These data suggest that prodrug derivatives of ANAA and AcApNA could have potential as chemotherapeutic agents for the treatment of prostate cancer tumors that overexpress OPH

  6. Amino acid derivatives of 5-ASA as novel prodrugs for intestinal drug delivery.

    Science.gov (United States)

    Clerici, C; Gentili, G; Boschetti, E; Santucci, C; Aburbeh, A G; Natalini, B; Pellicciari, R; Morelli, A

    1994-12-01

    In an attempt to obtain site-specific delivery of 5-ASA in the intestinal tract, we have determined the extent of absorption and metabolism of a number of novel 5-ASA derivatives, namely, (N-L-glutamyl)-amino-2-salicylic acid (1), (N-L-aspartyl)-amino-2-salicylic-acid (2), 5-aminosalicyl-L-proline-L-leucine (3), and 5-(N-L-glutamyl)-aminosalicyl-L-proline-L-leucine (4), which are selectively cleaved by intestinal brush border aminopeptidase A and carboxypeptidases. These novel prodrugs, 5-ASA, and sulfasalazine were administered to adult Fisher rats (N = 30) and to animals that had undergone prior colostomy (N = 30). Urine and feces were collected at timed intervals for 48 hr and the metabolites, 5-ASA, and N-acetyl-5-ASA were measured by high-performance liquid chromatography. The absorption and metabolism of all compounds were essentially identical in colostomized and normal animals. 5-ASA exhibited a rapid proximal intestinal absorption as evidenced by the high cumulative urinary excretion (> 65%) and low fecal excretion. Sulfasalazine, as expected, exhibited a lower urinary recovery (metabolite. The novel glutamate and aspartate derivatives (1 and 2) behaved similarly to sulfasalazine, while administration of the proline-leucine derivative (3) resulted in urinary and fecal recovery values intermediate with respect to those observed with 5-ASA and sulfasalazine. 5-(N-L-Glutamyl)-aminosalicyl-L-proline-L-leucine yielded the highest fecal recovery of 5-ASA and its N-acetyl derivative, indicating a more efficient delivery to the distal bowel. Amino acid derivatives of 5-ASA appear to be potentially useful prodrugs for the site-specific delivery of 5-ASA to different regions of the intestinal tract.

  7. Formation Rate-Limited Pharmacokinetics of Biologically Active Epoxy Transformers of Prodrug Treosulfan.

    Science.gov (United States)

    Romański, Michał; Kasprzyk, Anna; Karbownik, Agnieszka; Szałek, Edyta; Główka, Franciszek K

    2016-05-01

    A prodrug treosulfan (TREO) is being evaluated in clinical trials as a myeloablative agent before hematopoietic stem cell transplantation. The active derivatives of TREO, monoepoxide (EBDM), and diepoxide (DEB) are formed in a pH-dependent nonenzymatic reaction. The aim of the study was to investigate pharmacokinetics of the TREO epoxy transformers in a rabbit model and explain the causes of low plasma concentrations of EBDM and DEB observed in patients receiving high-dose TREO before hematopoietic stem cell transplantation. New Zealand white rabbits (n = 5 per cohort) received an intravenous infusion of TREO (group I), injection of DEB (group II), and injection of a solution containing EBDM (group III). When EBDM and DEB were administered to the rabbits, they underwent a very rapid elimination (half-life 0.069 and 0.046 h) associated with a high systemic clearance (10.0 and 14.0 L h(-1) kg(-1)). After administration of TREO, the t1/2 of EBDM was statistically equal to the t1/2 of the prodrug (1.6 h). To conclude, after administration of TREO, its epoxy transformers demonstrate a formation-limited elimination. Then EBDM and DEB have the same elimination half-life as TREO, but the levels of EBDM and DEB in the body, including plasma, are much lower than TREO on account of their inherently high clearance. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  8. Quantitative modeling of the dynamics and intracellular trafficking of far-red light-activatable prodrugs: implications in stimuli-responsive drug delivery system.

    Science.gov (United States)

    Li, Mengjie; Thapa, Pritam; Rajaputra, Pallavi; Bio, Moses; Peer, Cody J; Figg, William D; You, Youngjae; Woo, Sukyung

    2017-12-01

    The combination of photodynamic therapy (PDT) with anti-tumor agents is a complimentary strategy to treat local cancers. We developed a unique photosensitizer (PS)-conjugated paclitaxel (PTX) prodrug in which a PS is excited by near-infrared wavelength light to site-specifically release PTX while generating singlet oxygen (SO) to effectively kill cancer cells with both PTX and SO. The aim of the present study was to identify the determinants influencing the combined efficacy of this light-activatable prodrug, especially the bystander killing effects from released PTX. Using PS-conjugated PTX as a model system, we developed a quantitative mathematical model describing the intracellular trafficking. Dynamics of the prodrug and the model predictions were verified with experimental data using human cancer cells in vitro. The sensitivity analysis suggested that parameters related to extracellular concentration of released PTX, prodrug uptake, target engagement, and target abundance are critical in determining the combined killing efficacy of the prodrug. We found that released PTX cytotoxicity was most sensitive to the retention time of the drug in extracellular space. Modulating drug internalization and conjugating the agents targeted to abundant receptors may provide a new strategy for maximizing the killing capacity of the far-red light-activatable prodrug system. These results provide guidance for the design of the PDT combination study in vivo and have implications for other stimuli-responsive drug delivery systems.

  9. Kinome profiling of Arabidopsis using arrays of kinase consensus substrates

    Directory of Open Access Journals (Sweden)

    Pieterse Corné MJ

    2007-02-01

    Full Text Available Abstract Background Kinome profiling aims at the parallel analysis of kinase activities in a cell. Novel developed arrays containing consensus substrates for kinases are used to assess those kinase activities. The arrays described in this paper were already used to determine kinase activities in mammalian systems, but since substrates from many organisms are present we decided to test these arrays for the determination of kinase activities in the model plant species Arabidopsis thaliana. Results Kinome profiling using Arabidopsis cell extracts resulted in the labelling of many consensus peptides by kinases from the plant, indicating the usefulness of this kinome profiling tool for plants. Method development showed that fresh and frozen plant material could be used to make cell lysates containing active kinases. Dilution of the plant extract increased the signal to noise ratio and non-radioactive ATP enhances full development of spot intensities. Upon infection of Arabidopsis with an avirulent strain of the bacterial pathogen Pseudomonas syringae pv. tomato, we could detect differential kinase activities by measuring phosphorylation of consensus peptides. Conclusion We show that kinome profiling on arrays with consensus substrates can be used to monitor kinase activities in plants. In a case study we show that upon infection with avirulent P. syringae differential kinase activities can be found. The PepChip can for example be used to purify (unknown kinases that play a role in P. syringae infection. This paper shows that kinome profiling using arrays of consensus peptides is a valuable new tool to study signal-transduction in plants. It complements the available methods for genomics and proteomics research.

  10. The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

    Science.gov (United States)

    Quan, Jing; Chen, Zhichun; Han, Chengyou; Lin, Xianfu

    2007-02-15

    A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.

  11. Radiation- and Photo-induced Activation of 5-Fluorouracil Prodrugs as a Strategy for the Selective Treatment of Solid Tumors

    Directory of Open Access Journals (Sweden)

    Sei-ichi Nishimoto

    2008-10-01

    Full Text Available 5-Fluorouracil (5-FU is used widely as an anticancer drug to treat solid cancers, such as colon, breast, rectal, and pancreatic cancers, although its clinical application is limited because 5-FU has gastrointestinal and hematological toxicity. Many groups are searching for prodrugs with functions that are tumor selective in their delivery and can be activated to improve the clinical utility of 5-FU as an important cancer chemotherapeutic agent. UV and ionizing radiation can cause chemical reactions in a localized area of the body, and these have been applied in the development of site-specific drug activation and sensitization. In this review, we describe recent progress in the development of novel 5-FU prodrugs that are activated site specifically by UV light and ionizing radiation in the tumor microenvironment. We also discuss the chemical mechanisms underlying this activation.

  12. Suppression of inflammation in a mouse model of rheumatoid arthritis using targeted lipase-labile fumagillin prodrug nanoparticles

    OpenAIRE

    Zhou, Hui-fang; Yan, Huimin; Senpan, Angana; Wickline, Samuel A.; Pan, Dipanjan; Lanza, Gregory M.; Pham, Christine T.N.

    2012-01-01

    Nanoparticle-based therapeutics are emerging technologies that have the potential to greatly impact the treatment of many human diseases. However, drug instability and premature release from the nanoparticles during circulation currently preclude clinical translation. Herein, we use a lipase-labile (Sn 2) fumagillin prodrug platform coupled with a unique lipid surface-to-surface targeted delivery mechanism, termed contact-facilitated drug delivery, to counter the premature drug release and ov...

  13. Magnetic resonance imaging and spectroscopy of combretastatin A4 prodrug-induced disruption of tumour perfusion and energetic status

    OpenAIRE

    1998-01-01

    The effects of combretastatin A4 prodrug on perfusion and the levels of 31P metabolites in an implanted murine tumour were investigated for 3 h after drug treatment using nuclear magnetic resonance imaging (MRI) and spectroscopy (MRS). The area of regions of low signal intensity in spin-echo images of tumours increased slightly after treatment with the drug. These regions of low signal intensity corresponded to necrosis seen in histological sections, whereas the expanding regions surrounding ...

  14. Synthesis and evaluation of macromolecule-bound derivatives of a peptidyl-1-beta-D-arabinofuranosylcytosine prodrug.

    Science.gov (United States)

    Balajthy, Zoltan

    2008-04-01

    Macromolecule-bound Val-Leu-Lys-ara-C (1) prodrugs were synthesized with spacers (-HN-(CH(2))(x)-CO-; x =1,3,5) between the dextran carrier (T-70) and 1, in order to achieve a sustained-release drug delivery system dextran-NH-(CH(2))(x:1,3,5)-CO-Val-Leu-Lys-ara-C (5, 6 and 7). The conjugation increased the stability of 1 in aqueous buffer solutions by three times (t((1/2)) 53.0 h, pH 7.4). The length of spacer also regulated the rate of hydrolysis of the prodrugs in serum. The shortest spacer (-HN-(CH(2))-CO-, (2)) in 5 provided the best protection of 1 against the hydrolyzing ability of proteinase- alpha(2)-macroglobulin complexes, increasing its half-life approximately 30-fold. The conjugation procedure resulted in a growth arrest ability for macromolecular-bound prodrugs 5, 6 and 7 against L1210 with IC(50) of 0.01 microM in vitro, which is significantly lower than that of other ara-C-macromolecule conjugates. 5 and 6 arrested cell growth in a broader range of concentration, between 1 x 10(-5)-1.0 microM, than ara-C could.

  15. Vital role of protein kinase C-related kinase (PRK1) in the formation and stability of neurites during hypoxia

    OpenAIRE

    Thauerer, Bettina; zur Nedden, Stephanie; Baier-Bitterlich, Gabriele

    2010-01-01

    Exposure of pheochromocytoma (PC12) cells to hypoxia (1% O2) favors differentiation at the expense of cell viability. Additional incubation with nerve growth factor (NGF) and guanosine, a purine nucleoside with neurotrophin characteristics, rescued cell viability and further enhanced the extension of neurites. In parallel, an increase in the activity of protein kinase C-related kinase (PRK1), which is known to be involved in regulation of the actin cytoskeleton, was observed in hypoxic cells....

  16. Ribosomal S6 Kinase Cooperates with Casein Kinase 2 to Modulate the Drosophila Circadian Molecular Oscillator

    Science.gov (United States)

    Akten, Bikem; Tangredi, Michelle M.; Jauch, Eike; Roberts, Mary A.; Ng, Fanny; Raabe, Thomas; Jackson, F. Rob

    2009-01-01

    There is a universal requirement for post-translational regulatory mechanisms in circadian clock systems. Previous work in Drosophila has identified several kinases, phosphatases and an E3 ligase that are critical for determining the nuclear translocation and/or stability of clock proteins. The present study evaluated the function of p90 ribosomal S6 kinase (RSK) in the Drosophila circadian system. In mammals, RSK1 is a light- and clock-regulated kinase known to be activated by the MAPK pathway, but there is no direct evidence that it functions as a component of the circadian system. Here, we show that Drosophila S6KII RNA displays rhythms in abundance, indicative of circadian control. Importantly, an S6KII null mutant exhibits a short-period circadian phenotype that can be rescued by expression of the wild-type gene in clock neurons, indicating a role for S6KII in the molecular oscillator. Peak PER clock protein expression is elevated in the mutant, indicative of enhanced stability, whereas per mRNA level is decreased, consistent with enhanced feedback repression. Gene reporter assays show that decreased S6KII is associated with increased PER repression. Surprisingly, we demonstrate a physical interaction between S6KII and the Casein Kinase 2 regulatory subunit (CK2β), suggesting a functional relationship between the two kinases. In support of such a relationship, there are genetic interactions between S6KII and CK2 mutations, in vivo, which indicate that CK2 activity is required for S6KII action. We propose that the two kinases cooperate within clock neurons to fine-tune circadian period, improving the precision of the clock mechanism. PMID:19144847

  17. Protein kinase substrate identification on functional protein arrays

    Directory of Open Access Journals (Sweden)

    Zhou Fang

    2008-02-01

    Full Text Available Abstract Background Over the last decade, kinases have emerged as attractive therapeutic targets for a number of different diseases, and numerous high throughput screening efforts in the pharmaceutical community are directed towards discovery of compounds that regulate kinase function. The emerging utility of systems biology approaches has necessitated the development of multiplex tools suitable for proteomic-scale experiments to replace lower throughput technologies such as mass spectroscopy for the study of protein phosphorylation. Recently, a new approach for identifying substrates of protein kinases has applied the miniaturized format of functional protein arrays to characterize phosphorylation for thousands of candidate protein substrates in a single experiment. This method involves the addition of protein kinases in solution to arrays of immobilized proteins to identify substrates using highly sensitive radioactive detection and hit identification algorithms. Results To date, the factors required for optimal performance of protein array-based kinase substrate identification have not been described. In the current study, we have carried out a detailed characterization of the protein array-based method for kinase substrate identification, including an examination of the effects of time, buffer compositions, and protein concentration on the results. The protein array approach was compared to standard solution-based assays for assessing substrate phosphorylation, and a correlation of greater than 80% was observed. The results presented here demonstrate how novel substrates for protein kinases can be quickly identified from arrays containing thousands of human proteins to provide new clues to protein kinase function. In addition, a pooling-deconvolution strategy was developed and applied that enhances characterization of specific kinase-substrate relationships and decreases reagent consumption. Conclusion Functional protein microarrays are an

  18. Protein Kinase Mitogen-activated Protein Kinase Kinase Kinase Kinase 4 (MAP4K4) Promotes Obesity-induced Hyperinsulinemia.

    Science.gov (United States)

    Roth Flach, Rachel J; Danai, Laura V; DiStefano, Marina T; Kelly, Mark; Menendez, Lorena Garcia; Jurczyk, Agata; Sharma, Rohit B; Jung, Dae Young; Kim, Jong Hun; Kim, Jason K; Bortell, Rita; Alonso, Laura C; Czech, Michael P

    2016-07-29

    Previous studies revealed a paradox whereby mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) acted as a negative regulator of insulin sensitivity in chronically obese mice, yet systemic deletion of Map4k4 did not improve glucose tolerance. Here, we report markedly reduced glucose-responsive plasma insulin and C-peptide levels in whole body Map4k4-depleted mice (M4K4 iKO) as well as an impaired first phase of insulin secretion from islets derived from M4K4 iKO mice ex vivo After long-term high fat diet (HFD), M4K4 iKO mice pancreata also displayed reduced β cell mass, fewer proliferating β cells and reduced islet-specific gene mRNA expression compared with controls, although insulin content was normal. Interestingly, the reduced plasma insulin in M4K4 iKO mice exposed to chronic (16 weeks) HFD was not observed in response to acute HFD challenge or short term treatment with the insulin receptor antagonist S961. Furthermore, the improved insulin sensitivity in obese M4K4 iKO mice was abrogated by high exogenous insulin over the course of a euglycemic clamp study, indicating that hypoinsulinemia promotes insulin sensitivity in chronically obese M4K4 iKO mice. These results demonstrate that protein kinase Map4k4 drives obesity-induced hyperinsulinemia and insulin resistance in part by promoting insulin secretion from β cells in mice. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Regulation of Autophagy by Kinases

    International Nuclear Information System (INIS)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets

  20. Regulation of Autophagy by Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda, E-mail: alakananda.basu@unthsc.edu [Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-06-09

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  1. Regulation of Autophagy by Kinases

    Science.gov (United States)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets. PMID:24212825

  2. Regulation of Autophagy by Kinases

    Directory of Open Access Journals (Sweden)

    Savitha Sridharan

    2011-06-01

    Full Text Available Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  3. Ghrelin augments murine T-cell proliferation by activation of the phosphatidylinositol-3-kinase, extracellular signal-regulated kinase and protein kinase C signaling pathways

    Science.gov (United States)

    Lee, Jun Ho; Patel, Kalpesh; Tae, Hyun Jin; Lustig, Ana; Kim, Jie Wan; Mattson, Mark P.; Taub, Dennis D.

    2014-01-01

    Thymic atrophy occurs during normal aging, and is accelerated by exposure to chronic stressors that elevate glucocorticoid levelsand impair the naïve T cell output. The orexigenic hormone ghrelin was recently shown to attenuate age-associated thymic atrophy. Here, we report that ghrelin enhances the proliferation of murine CD4+ primary T cells and a CD4+ T-cell line. Ghrelin induced activation of the ERK1/2 and Akt signaling pathways, via upstream activation of phosphatidylinositol-3-kinase and protein kinase C, to enhance T-cell proliferation. Moreover, ghrelin induced expression of the cell cycle proteins cyclin D1, cyclin E, cyclin-dependent kinase 2 (CDK2) and retinoblastoma phosphorylation. Finally, ghrelin activated the above-mentioned signaling pathways and stimulated thymocyte proliferation in young and older mice in vivo. PMID:25447526

  4. Nonaqueous gel for the transdermal delivery of a DTPA penta-ethyl ester prodrug.

    Science.gov (United States)

    Zhang, Yong; Sadgrove, Matthew P; Sueda, Katsuhiko; Yang, Yu-Tsai; Pacyniak, Erik K; Kagel, John R; Braun, Brenda A; Zamboni, William C; Mumper, Russell J; Jay, Michael

    2013-04-01

    Diethylenetriamine pentaacetic acid penta-ethyl ester, designated as C2E5, was successfully incorporated into a nonaqueous gel for transdermal delivery. The thermal and rheological properties of a formulation containing 40% C2E5, 20% ethyl cellulose, and 40% Miglyol 840® prepared using the solvent evaporation method demonstrated that the gel had acceptable content uniformity and flow properties. In vitro studies showed that C2E5 was steadily released from the gel at a rate suitable for transdermal delivery. Topical application of the gel at a 200 mg C2E5/kg dose level in rats achieved significantly higher plasma exposures of several active metabolites compared with neat C2E5 oil at the same dose level. The results suggest that transdermal delivery of a chelator prodrug is an effective radionuclide decorporation strategy by delivering chelators to the circulation with a pharmacokinetic profile that is more consistent with the biokinetic profile of transuranic elements in contaminated individuals.

  5. Design, Synthesis and Hydrolytic Behavior of Mutual Prodrugs of NSAIDs with Gabapentin Using Glycol Spacers

    Directory of Open Access Journals (Sweden)

    Hiba Najeh Alsaad

    2012-10-01

    Full Text Available The free –COOH present in NSAIDs is thought to be responsible for the GI irritation associated with all traditional NSAIDs. Exploitation of mutual prodrugs is an approach wherein the NSAID is covalently bounded to a second pharmacologically active carrier/drug with the ultimate aim of reducing the gastric irritation. In this study some NSAIDs were conjugated with gabapentin via ester bonds using glycol spacers with the expectation of reducing gastric adverse effects and obtaining synergistic analgesic effects. The kinetics of ester hydrolysis were studied in two different non enzymatic buffer solutions at pH 1.2 and 7.4, as well as in 80% human plasma using HPLC with chloroform -methanol as mobile phase. Compounds 9a–c with ethylene glycol spacers showed significant stability at buffer solutions with half lives ranging from about 8–25 h, while the underwent a reasonable plasma hydrolysis (49%–88% in 2 h. Compound 9d with a propylene glycol spacer shows a higher rate of enzymatic hydrolysis than the corresponding ethylene glycol compound 9c. The result of compounds 9a-c indicate that these compounds may be stable during their passage through the GIT until reaching the blood circulation.

  6. para-Aminosalicylic acid is a prodrug targeting dihydrofolate reductase in Mycobacterium tuberculosis.

    Science.gov (United States)

    Zheng, Jun; Rubin, Eric J; Bifani, Pablo; Mathys, Vanessa; Lim, Vivian; Au, Melvin; Jang, Jichan; Nam, Jiyoun; Dick, Thomas; Walker, John R; Pethe, Kevin; Camacho, Luis R

    2013-08-09

    para-Aminosalicylic acid (PAS) is one of the antimycobacterial drugs currently used for multidrug-resistant tuberculosis. Although it has been in clinical use for over 60 years, its mechanism(s) of action remains elusive. Here we report that PAS is a prodrug targeting dihydrofolate reductase (DHFR) through an unusual and novel mechanism of action. We provide evidences that PAS is incorporated into the folate pathway by dihydropteroate synthase (DHPS) and dihydrofolate synthase (DHFS) to generate a hydroxyl dihydrofolate antimetabolite, which in turn inhibits DHFR enzymatic activity. Interestingly, PAS is recognized by DHPS as efficiently as its natural substrate para-amino benzoic acid. Chemical inhibition of DHPS or mutation in DHFS prevents the formation of the antimetabolite, thereby conferring resistance to PAS. In addition, we identified a bifunctional enzyme (riboflavin biosynthesis protein (RibD)), a putative functional analog of DHFR in a knock-out strain. This finding is further supported by the identification of PAS-resistant clinical isolates encoding a RibD overexpression mutation displaying cross-resistance to genuine DHFR inhibitors. Our findings reveal that a metabolite of PAS inhibits DHFR in the folate pathway. RibD was shown to act as a functional analog of DHFR, and as for DHFS, both were shown to be associated in PAS resistance in laboratory strains and clinical isolates.

  7. Tumor-activated prodrug (TAP)-conjugated nanoparticles with cleavable domains for safe doxorubicin delivery.

    Science.gov (United States)

    Guarnieri, Daniela; Biondi, Marco; Yu, Hui; Belli, Valentina; Falanga, Andrea P; Cantisani, Marco; Galdiero, Stefania; Netti, Paolo A

    2015-03-01

    A major issue in chemotherapy is the lack of specificity of many antitumor drugs, which cause severe side effects and an impaired therapeutic response. Here we report on the design and characterization of model tumor activated prodrug-conjugated polystyrene (PS) nanoparticles (TAP-NPs) for the release of doxorubicin (Dox) triggered by matrix metalloprotease-2 (MMP2) enzyme, which is overexpressed in the extracellular matrix of tumors. In particular, TAP-NPs were produced by attaching Dox to poly(ethylene glycol) (PEG) through two MMP2-cleavable enzymes. The resulting adduct was then tethered to PS NPs. Results showed that Dox release was actually triggered by MMP2 cleavage and was dependent on enzyme concentration, with a plateau around 20 nM. Furthermore, significant cell cytotoxicity was observed towards three cell lines only in the presence of MMP2, but not in cells without enzyme pre-treatment, even after NP internalization by cells. These findings indicate the potential of TAP-NPs as suitable nanocarriers for an on demand, tumor--specific delivery of antitumor drugs after the response to an endogenous stimulus. Further advancements will focus on the translation of this production technology to biodegradable systems for the safe transport of cytotoxic drug to tumor tissues. © 2014 Wiley Periodicals, Inc.

  8. Ticlopidine in Its Prodrug Form Is a Selective Inhibitor of Human NTPDase1

    Directory of Open Access Journals (Sweden)

    Joanna Lecka

    2014-01-01

    Full Text Available Nucleoside triphosphate diphosphohydrolase-1 (NTPDase1, like other ectonucleotidases, controls extracellular nucleotide levels and consequently their (pathophysiological responses such as in thrombosis, inflammation, and cancer. Selective NTPDase1 inhibitors would therefore be very useful. We previously observed that ticlopidine in its prodrug form, which does not affect P2 receptor activity, inhibited the recombinant form of human NTPDase1 (Ki=14 μM. Here we tested whether ticlopidine can be used as a selective inhibitor of NTPDase1. We confirmed that ticlopidine inhibits NTPDase1 in different forms and in different assays. The ADPase activity of intact HUVEC as well as of COS-7 cells transfected with human NTPDase1 was strongly inhibited by 100 µM ticlopidine, 99 and 86%, respectively. Ticlopidine (100 µM completely inhibited the ATPase activity of NTPDase1 in situ as shown by enzyme histochemistry with human liver and pancreas sections. Ticlopidine also inhibited the activity of rat and mouse NTPDase1 and of potato apyrase. At 100 µM ticlopidine did not affect the activity of human NTPDase2, NTPDase3, and NTPDase8, nor of NPP1 and NPP3. Weak inhibition (10–20% of NTPDase3 and -8 was observed at 1 mM ticlopidine. These results show that ticlopidine is a specific inhibitor of NTPDase1 that can be used in enzymatic and histochemistry assays.

  9. Manageable cytotoxicity of nanocapsules immobilizing D-amino acid oxidase via exogenous administration of nontoxic prodrug

    Science.gov (United States)

    Zhao, Yang; Zhu, Yingchun; Fu, Jingke

    2014-02-01

    D-Amino acid oxidase (DAO), which could catalyze generation of hydrogen peroxide with strong oxidbility and cytotoxicity, has become of interest as a biocatalyst for therapeutic treatments. Herein we report that amino-functional hollow mesoporous silica with large pore size (10.27 nm) and positively charged surface effectively immobilize DAO with negative charge. The adsorption, activity and stability of DAO are demonstrated to depend mainly on the amino-functionalization of surface. Significant cancer cell killing effect is observed when the cells are treated by the nanocapsules entrapping DAO together with D-alanine, showing distinct dose-dependency on concentration of the nanocapsules entrapping DAO or D-alanine. Nevertheless, the toxicity is completely neutralized by the addition of catalase, and anti-tumor effect is not observed when either the nanocapsules entrapping DAO or D-alanine is applied alone. The results indicate that cytotoxicity of the nanocapsules entrapping DAO could be managed by exogenous administration of nontoxic prodrug to tumor tissue, due to the stereoselectivity of DAO and the scarcity of its substrates in mammalian organisms. Thus, the method might be exploited as a potential treatment for cancer therapy.

  10. Targeting hypoxic microenvironment of pancreatic xenografts with the hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Lohse, Ines; Rasowski, Joanna; Cao, Pinjiang; Pintilie, Melania; Do, Trevor; Tsao, Ming-Sound; Hill, Richard P; Hedley, David W

    2016-06-07

    Previous reports have suggested that the hypoxic microenvironment provides a niche that supports tumor stem cells, and that this might explain clinical observations linking hypoxia to metastasis. To test this, we examined the effects of a hypoxia-activated prodrug, TH-302, on the tumor-initiating cell (TIC) frequency of patient-derived pancreatic xenografts (PDX).The frequencies of TIC, measured by limiting dilution assay, varied widely in 11 PDX models, and were correlated with rapid growth but not with the levels of hypoxia. Treatment with either TH-302 or ionizing radiation (IR), to target hypoxic and well-oxygenated regions, respectively, reduced TIC frequency, and the combination of TH-302 and IR was much more effective in all models tested. The combination was also more effective than TH-302 or IR alone controlling tumor growth, particularly treating the more rapidly-growing/hypoxic models. These findings support the clinical utility of hypoxia targeting in combination with radiotherapy to treat pancreatic cancers, but do not provide strong evidence for a hypoxic stem cell niche.

  11. Menahydroquinone-4 Prodrug: A Promising Candidate Anti-Hepatocellular Carcinoma Agent.

    Science.gov (United States)

    Enjoji, Munechika; Watase, Daisuke; Matsunaga, Kazuhisa; Kusuda, Mariko; Nagata-Akaho, Nami; Karube, Yoshiharu; Takata, Jiro

    2015-07-22

    Recently, new therapeutics have been developed for hepatocellular carcinoma (HCC). However, the overall survival rate of HCC patients is still unsatisfactory; one of the reasons for this is the high frequency of recurrence after radical treatment. Consequently, to improve prognosis, it will be important to develop a novel anti-tumor agent that is especially effective against HCC recurrence. For clinical application, long-term safety, together with high anti-tumor efficacy, is desirable. Recent studies have proposed menahydroquinone-4 1,4-bis- N,N -dimethylglycinate hydrochloride (MKH-DMG), a prodrug of menahydroquinone-4 (MKH), as a promising candidate for HCC treatment including the inhibition of recurrence; MKH-DMG has been shown to achieve good selective accumulation of MKH in tumor cells, resulting in satisfactory inhibition of cell proliferation in des-γ-carboxyl prothrombin (DCP)-positive and DCP-negative HCC cell lines. In a spleen-liver metastasis mouse model, MKH-DMG has been demonstrated to have anti-proliferation and anti-metastatic effects in vivo . The characteristics of MKH-DMG as a novel anti-HCC agent are presented in this review article.

  12. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten

    2010-01-01

    in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by tyrosine......Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... and highlighted their importance in bacterial physiology. Having no orthologues in Eukarya, BY-kinases are receiving a growing attention from the biomedical field, since they represent a particularly promising target for anti-bacterial drug design....

  13. Synergistic induction of apoptosis in multiple myeloma cells by bortezomib and hypoxia-activated prodrug TH-302, in vivo and in vitro.

    Science.gov (United States)

    Hu, Jinsong; Van Valckenborgh, Els; Xu, Dehui; Menu, Eline; De Raeve, Hendrik; De Bruyne, Elke; De Bryune, Elke; Xu, Song; Van Camp, Ben; Handisides, Damian; Hart, Charles P; Vanderkerken, Karin

    2013-09-01

    Recently, we showed that hypoxia is a critical microenvironmental factor in multiple myeloma, and that the hypoxia-activated prodrug TH-302 selectively targets hypoxic multiple myeloma cells and improves multiple disease parameters in vivo. To explore approaches for sensitizing multiple myeloma cells to TH-302, we evaluated in this study the antitumor effect of TH-302 in combination with the clinically used proteasome inhibitor bortezomib. First, we show that TH-302 and bortezomib synergistically induce apoptosis in multiple myeloma cell lines in vitro. Second, we confirm that this synergism is related to the activation of caspase cascades and is mediated by changes of Bcl-2 family proteins. The combination treatment induces enhanced cleavage of caspase-3/8/9 and PARP, and therefore triggers apoptosis and enhances the cleavage of proapoptotic BH3-only protein BAD and BID as well as the antiapoptotic protein Mcl-1. In particular, TH-302 can abrogate the accumulation of antiapoptotic Mcl-1 induced by bortezomib, and decreases the expression of the prosurvival proteins Bcl-2 and Bcl-xL. Furthermore, we found that the induction of the proapoptotic BH3-only proteins PUMA (p53-upregulated modulator of apoptosis) and NOXA is associated with this synergism. In response to the genotoxic and endoplasmic reticulum stresses by TH-302 and bortezomib, the expression of PUMA and NOXA were upregulated in p53-dependent and -independent manners. Finally, in the murine 5T33MMvv model, we showed that the combination of TH-302 and bortezomib can improve multiple disease parameters and significantly prolong the survival of diseased mice. In conclusion, our studies provide a rationale for clinical evaluation of the combination of TH-302 and bortezomib in patients with multiple myeloma.

  14. Growth- and Stress-Induced PASTA Kinase Phosphorylation in Enterococcus faecalis.

    Science.gov (United States)

    Labbe, Benjamin D; Kristich, Christopher J

    2017-11-01

    Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes Such PASTA kinases regulate critical processes, including antibiotic resistance, cell division, toxin production, and virulence, and are essential for viability in certain organisms. Based on in vitro studies with purified extracellular and intracellular fragments of PASTA kinases, a model for signaling has been proposed, in which the extracellular PASTA domains bind currently undefined ligands (typically thought to be peptidoglycan, or fragments thereof) to drive kinase dimerization, which leads to enhanced kinase autophosphorylation and enhanced phosphorylation of substrates. However, this model has not been rigorously tested in vivo Enterococcus faecalis is a Gram-positive intestinal commensal and major antibiotic-resistant opportunistic pathogen. In E. faecalis , the PASTA kinase IreK drives intrinsic resistance to cell wall-active antimicrobials, suggesting that such antimicrobials may trigger IreK signaling. Here we show that IreK responds to cell wall stress in vivo by enhancing its phosphorylation and that of a downstream substrate. This response requires both the extracellular PASTA domains and specific phosphorylatable residues in the kinase domain. Thus, our results provide in vivo evidence, with an intact full-length PASTA kinase in its native physiological environment, that supports the prevailing model of PASTA kinase signaling. In addition, we show that IreK responds to a signal associated with growth and/or cell division, in the absence of cell wall-active antimicrobials. Surprisingly, the ability of IreK to respond to growth and/or division does not require the extracellular PASTA domains, suggesting that IreK monitors multiple parameters for sensory input in vivo IMPORTANCE Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes and regulate critical processes. The

  15. pH-sensitive pHluorins as a molecular sensor for in situ monitoring of enzyme-catalyzed prodrug activation.

    Science.gov (United States)

    Liu, Hui; Cao, Xiaodan; Wang, Ping; Ma, Xingyuan

    2017-07-01

    This work examines the feasibility of using a pH-sensitive fluorescent protein as a molecular reporter for enzyme-catalyzed prodrug activation reaction. Specifically, a ratiometric pHluorins was examined for detection of the activity of horseradish peroxidase (HRP) for the activation of indole-3-acetic acid. The pHluorins and HRP were conjugated chemically, forming a biocatalyst with a self-reporting function. Results showed that the characteristic fluorescence intensity ratio of the conjugate shifted from 1.47 to 1.40 corresponding to the progress of the prodrug activation reaction. The effectiveness of applying the conjugate for inhibition of the growth of Bcap-37 cells was also demonstrated simultaneously with reaction monitoring. The results reveal a very promising approach to realizing in situ monitoring of enzyme activities based on pH shifting for enzyme-based prodrug therapy applications. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  16. Prolonged naproxen joint residence time after intra-articular injection of lipophilic solutions comprising a naproxen glycolamide ester prodrug in the rat

    DEFF Research Database (Denmark)

    Thing, Mette; Lu, Yi; Agårdh, Li

    2013-01-01

    time. Two oils, medium-chain triglycerides and castor oil, differing with respect to viscosity were tested. After intra-articular administration of oil prodrug solutions, a significant increase in the time to maximum naproxen serum concentration from around 40 to 245min, an increase in the MRTj from......Intra-articular injection of oil solutions of lipophilic prodrugs that rapidly degrade to their parent compound in synovial fluid may constitute a feasible approach to increase the joint residence time of non-steroidal anti-inflammatory drugs. In this in vivo study, oil solutions of the N......,N-diethyl glycolamide ester prodrug of naproxen (16mg/ml) were injected into the rat knee joint by dosing 6μl formulation per 100g body weight. The sustained release properties were compared to those of intra-articularly injected aqueous and oil solutions of naproxen by monitoring the naproxen serum concentrations over...

  17. A phase I trial of PR-104, a pre-prodrug of the bioreductive prodrug PR-104A, given weekly to solid tumour patients

    International Nuclear Information System (INIS)

    McKeage, Mark J; Gu, Yongchuan; Wilson, William R; Hill, Andrew; Amies, Karen; Melink, Teresa J; Jameson, Michael B

    2011-01-01

    The phosphate ester PR-104 is rapidly converted in vivo to the alcohol PR-104A, a nitrogen mustard prodrug that is metabolised to hydroxylamine (PR-104H) and amine (PR-104M) DNA crosslinking agents by one-electron reductases in hypoxic cells and by aldo-keto reductase 1C3 independently of oxygen. In a previous phase I study using a q 3 week schedule of PR-104, the maximum tolerated dose (MTD) was 1100 mg/m 2 and fatigue, neutropenic fever and infection were dose-limiting. The primary objective of the current study was to determine the dose-limiting toxicity (DLT) and MTD of weekly PR-104. Patients with advanced solid tumours received PR-104 as a 1-hour intravenous infusion on days 1, 8 and 15 every 28 days with assessment of pharmacokinetics on cycle 1 day 1. Twenty-six patients (pts) were enrolled (16 male/10 female; median age 58 yrs, range 30 to 70 yrs) who had received a median of two prior chemotherapy regimens (range, 0 to 3) for melanoma (8 pts), colorectal or anal cancer (3 pts), NSCLC (3 pts), sarcoma (3 pts), glioblastoma (2 pts), salivary gland tumours (2 pts) or other solid tumours (5 pts). PR-104 was administered at 135 mg/m 2 (3 pts), 270 mg/m 2 (6 pts), 540 mg/m 2 (6 pts), 675 mg/m 2 (7 pts) and 900 mg/m 2 (4 pts) for a median of two treatment cycles (range, 1 to 7 cycles) and five infusions (range, 1 to 18) per patient. Dose-limiting toxicities (DLTs) during cycle one included grade four thrombocytopenia at 540 mg/m 2 (1 of 6 pts) and grade four thrombocytopenia and neutropenia at 900 mg/m 2 (2 of 4 pts). At an intermediate dose of 675 mg/m 2 , there were no DLTs among a total of seven patients given 12 treatment cycles but all experienced moderate to severe (grade 2 to 4) haematological toxicity. Thrombocytopenia was delayed in its onset and nadir, and its recovery was protracted and incomplete in many patients. There were no complete or partial tumour responses. PR-104-induced thrombocytopenia and neutropenia correlated with plasma AUC of PR-104

  18. Hydroxyurea enhances the activity of acyclovir and cidofovir against herpes simplex virus type 1 resistant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes.

    Science.gov (United States)

    Sergerie, Yan; Boivin, Guy

    2008-01-01

    Drug-resistant herpes simplex virus type 1 (HSV-1) recombinant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes were evaluated for their susceptibility to various antivirals in the presence of 25 microg/ml of hydroxyurea (HyU). The latter compound decreased the 50% inhibitory concentrations of acyclovir by 1.5-3.8-fold and that of cidofovir by 2.7-14.4-fold. However, HyU did not affect the susceptibilities of the various recombinant mutants to foscarnet. Hydroxyurea, a ribonucleotide reductase inhibitor, can increase the activity of nucleoside/nucleotide analogues against drug-resistant viruses.

  19. Nuclear localization of Lyn tyrosine kinase mediated by inhibition of its kinase activity

    International Nuclear Information System (INIS)

    Ikeda, Kikuko; Nakayama, Yuji; Togashi, Yuuki; Obata, Yuuki; Kuga, Takahisa; Kasahara, Kousuke; Fukumoto, Yasunori; Yamaguchi, Naoto

    2008-01-01

    Src-family kinases, cytoplasmic enzymes that participate in various signaling events, are found at not only the plasma membrane but also subcellular compartments, such as the nucleus, the Golgi apparatus and late endosomes/lysosomes. Lyn, a member of the Src-family kinases, is known to play a role in DNA damage response and cell cycle control in the nucleus. However, it is still unclear how the localization of Lyn to the nucleus is regulated. Here, we investigated the mechanism of the distribution of Lyn between the cytoplasm and the nucleus in epitheloid HeLa cells and hematopoietic THP-1 cells. Lyn was definitely detected in purified nuclei by immunofluorescence and immunoblotting analyses. Nuclear accumulation of Lyn was enhanced upon treatment of cells with leptomycin B (LMB), an inhibitor of Crm1-mediated nuclear export. Moreover, Lyn mutants lacking the sites for lipid modification were highly accumulated in the nucleus upon LMB treatment. Intriguingly, inhibition of the kinase activity of Lyn by SU6656, Csk overexpression, or point mutation in the ATP-binding site induced an increase in nuclear Lyn levels. These results suggest that Lyn being imported into and rapidly exported from the nucleus preferentially accumulates in the nucleus by inhibition of the kinase activity and lipid modification

  20. Validation and implementation of liquid chromatographic-mass spectrometric (LC-MS) methods for the quantification of tenofovir prodrugs.

    Science.gov (United States)

    Hummert, Pamela; Parsons, Teresa L; Ensign, Laura M; Hoang, Thuy; Marzinke, Mark A

    2018-04-15

    The nucleotide reverse transcriptase inhibitor tenofovir (TFV) is widely administered in a disoproxil prodrug form (tenofovir disoproxil fumarate, TDF) for HIV management and prevention. Recently, novel prodrugs tenofovir alafenamide fumarate (TAF) and hexadecyloxypropyl tenofovir (CMX157) have been pursued for HIV treatment while minimizing adverse effects associated with systemic TFV exposure. Dynamic and sensitive bioanalytical tools are required to characterize the pharmacokinetics of these prodrugs in systemic circulation. Two parallel methods have been developed, one to combinatorially quantify TAF and TFV, and a second method for CMX157 quantification, in plasma. K 2 EDTA plasma was spiked with TAF and TFV, or CMX157. Following the addition of isotopically labeled internal standards and sample extraction via solid phase extraction (TAF and TFV) or protein precipitation (CMX157), samples were subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. For TAF and TFV, separation occurred using a Zorbax Eclipse Plus C18 Narrow Bore RR, 2.1 × 50 mm, 3.5 μm column and analytes were detected on an API5000 mass analyzer; CMX157 was separated using a Kinetex C8, 2.1 × 50 mm, 2.6 μm column and quantified using an API4500 mass spectrometer. Methods were validated according to FDA Bioanalytical Method Validation guidelines. Analytical methods: were optimized for the multiplexed monitoring of TAF and TFV, and CMX157 in plasma. The lower limits of quantification (LLOQs) for TAF, TFV, and CMX157 were 0.03, 1.0, and 0.25 ng/mL, respectively. Calibration curves were generated via weighted linear regression of standards. Intra- and inter-assay precision and accuracy studies demonstrated %CVs ≤ 14.4% and %DEVs ≤ ± 7.95%, respectively. Stability and matrix effects studies were also performed. All results were acceptable and in accordance with the recommended guidelines for bioanalytical methods. Assays were also

  1. Preclinical Evaluation of Promitil, a Radiation-Responsive Liposomal Formulation of Mitomycin C Prodrug, in Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Xi; Warner, Samuel B.; Wagner, Kyle T.; Caster, Joseph M. [Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, Carolina Center for Cancer Nanotechnology Excellence, Carolina Institute of Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Zhang, Tian [Division of Medical Oncology, Department of Medicine, Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina (United States); Ohana, Patricia [Lipomedix Pharmaceuticals, Jerusalem (Israel); Gabizon, Alberto A. [Lipomedix Pharmaceuticals, Jerusalem (Israel); Shaare Zedek Medical Center, Jerusalem (Israel); Wang, Andrew Z., E-mail: zawang@med.unc.edu [Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, Carolina Center for Cancer Nanotechnology Excellence, Carolina Institute of Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States)

    2016-11-01

    Purpose: To examine the effect of radiation on in vitro drug activation and release of Promitil, a pegylated liposomal formulation of a mitomycin C (MMC) lipid-based prodrug; and examine the efficacy and toxicity of Promitil with concurrent radiation in colorectal cancer models. Methods and Materials: Promitil was obtained from Lipomedix Pharmaceuticals (Jerusalem, Israel). We tested the effects of radiation on release of active MMC from Promitil in vitro. We next examined the radiosensitization effect of Promitil in vitro. We further evaluated the toxicity of a single injection of free MMC or Promitil when combined with radiation by assessing the effects on blood counts and in-field skin and hair toxicity. Finally, we compared the efficacy of MMC and Promitil in chemoradiotherapy using mouse xenograft models. Results: Mitomycin C was activated and released from Promitil in a controlled-release profile, and the rate of release was significantly increased in medium from previously irradiated cells. Both Promitil and MMC potently radiosensitized HT-29 cells in vitro. Toxicity of MMC (8.4 mg/kg) was substantially greater than with equivalent doses of Promitil (30 mg/kg). Mice treated with human-equivalent doses of MMC (3.3 mg/kg) experienced comparable levels of toxicity as Promitil-treated mice at 30 mg/kg. Promitil improved the antitumor efficacy of 5-fluorouracil–based chemoradiotherapy in mouse xenograft models of colorectal cancer, while equitoxic doses of MMC did not. Conclusions: We demonstrated that Promitil is an attractive agent for chemoradiotherapy because it demonstrates a radiation-triggered release of active drug. We further demonstrated that Promitil is a well-tolerated and potent radiosensitizer at doses not achievable with free MMC. These results support clinical investigations using Promitil in chemoradiotherapy.

  2. Nitric oxide-releasing prodrug triggers cancer cell death through deregulation of cellular redox balance

    Directory of Open Access Journals (Sweden)

    Anna E. Maciag

    2013-01-01

    Full Text Available JS-K is a nitric oxide (NO-releasing prodrug of the O2-arylated diazeniumdiolate family that has demonstrated pronounced cytotoxicity and antitumor properties in a variety of cancer models both in vitro and in vivo. The current study of the metabolic actions of JS-K was undertaken to investigate mechanisms of its cytotoxicity. Consistent with model chemical reactions, the activating step in the metabolism of JS-K in the cell is the dearylation of the diazeniumdiolate by glutathione (GSH via a nucleophilic aromatic substitution reaction. The resulting product (CEP/NO anion spontaneously hydrolyzes, releasing two equivalents of NO. The GSH/GSSG redox couple is considered to be the major redox buffer of the cell, helping maintain a reducing environment under basal conditions. We have quantified the effects of JS-K on cellular GSH content, and show that JS-K markedly depletes GSH, due to JS-K's rapid uptake and cascading release of NO and reactive nitrogen species. The depletion of GSH results in alterations in the redox potential of the cellular environment, initiating MAPK stress signaling pathways, and inducing apoptosis. Microarray analysis confirmed signaling gene changes at the transcriptional level and revealed alteration in the expression of several genes crucial for maintenance of cellular redox homeostasis, as well as cell proliferation and survival, including MYC. Pre-treating cells with the known GSH precursor and nucleophilic reducing agent N-acetylcysteine prevented the signaling events that lead to apoptosis. These data indicate that multiplicative depletion of the reduced glutathione pool and deregulation of intracellular redox balance are important initial steps in the mechanism of JS-K's cytotoxic action.

  3. Thiopurine Prodrugs Mediate Immunosuppressive Effects by Interfering with Rac1 Protein Function*

    Science.gov (United States)

    Shin, Jin-Young; Wey, Michael; Umutesi, Hope G.; Sun, Xiangle; Simecka, Jerry; Heo, Jongyun

    2016-01-01

    6-Thiopurine (6-TP) prodrugs include 6-thioguanine and azathioprine. Both are widely used to treat autoimmune disorders and certain cancers. This study showed that a 6-thioguanosine triphosphate (6-TGTP), converted in T-cells from 6-TP, targets Rac1 to form a disulfide adduct between 6-TGTP and the redox-sensitive GXXXXGK(S/T)C motif of Rac1. This study also showed that, despite the conservation of the catalytic activity of RhoGAP (Rho-specific GAP) on the 6-TGTP-Rac1 adduct to produce the biologically inactive 6-thioguanosine diphosphate (6-TGDP)-Rac1 adduct, RhoGEF (Rho-specific GEF) cannot exchange the 6-TGDP adducted on Rac1 with free guanine nucleotide. The biologically inactive 6-TGDP-Rac1 adduct accumulates in cells because of the ongoing combined actions of RhoGEF and RhoGAP. Because other Rho GTPases, such as RhoA and Cdc42, also possess the GXXXXGK(S/T)C motif, the proposed mechanism for the inactivation of Rac1 also applies to RhoA and Cdc42. However, previous studies have shown that CD3/CD28-stimulated T-cells contain more activated Rac1 than other Rho GTPases such as RhoA and Cdc42. Accordingly, Rac1 is the main target of 6-TP in activated T-cells. This explains the T-cell-specific Rac1-targeting therapeutic action of 6-TP that suppresses the immune response. This proposed mechanism for the action of 6-TP on Rac1 performs a critical role in demonstrating the capability to design a Rac1-targeting chemotherapeutic agent(s) for autoimmune disorders. Nevertheless, the results also suggest that the targeting action of other Rho GTPases in other organ cells, such as RhoA in vascular cells, may be linked to cytotoxicities because RhoA plays a key role in vasculature functions. PMID:27189938

  4. Hypoxia targeting therapy with prodrug specifically stabilized and activated in hypoxic tumor cells

    International Nuclear Information System (INIS)

    Kondoh, S.K.; Ueda, T.; Harada, H.; Hiraoka, M.; Akagi, K.

    2003-01-01

    Hypoxia fraction in tumors is associated with increased metastasis and poor survival in patients suffering from malignant tumors such as the head and neck, cervical or breast cancers. Hypoxia can be a direct cause of therapeutic resistance because some drugs and radiation require oxygen to be maximally cytotoxic. Recently we have reported a novel hypoxia targeting prodrug, TOP3, which is a fusion protein, composed of HIV TAT protein transduction domain, a part of HIF1 α ODD domain, and Procaspase-3. TOP3 can be transferred into every cell both in vitro and in vivo but becomes stable only in hypoxic cells, in which TOP3 is activated and induces apoptosis. The application of this fusion protein to a tumor-bearing mouse resulted in significant suppression of the tumor growth and even in reduction of the tumor mass without any obvious side effects. The administrations of TOP3 in combination with a low dose of X-ray showed an additive antitumor effect on pancreatic tumor cells. Furthermore, we show that the rodent model of ascites generated by malignant cells provides an excellent platform of testing hypoxia targeting drugs, since it comprises homogeneous fluid with tumor cells surviving and proliferating under hypoxic condition. TOP3 induced apoptosis of AH130, rat ascites hepatoma cells, in vitro only under hypoxic but not normoxic condition. Intraperitoneal administration of TOP3 prolonged life span of the rats with AH130 derived malignant ascites. Sixty percent of the treated rats were cured of ascites without recurrence for more than six months, in contrast all untreated rats died within 20 days after tumor cell inoculation. These results strongly suggest that TOP3 would provide a new strategy for hypoxia targeting therapy and that the combination of TOP3 with radiotherapy or chemotherapy may provide a new strategy for annihilating malignant tumors

  5. Receptor-interacting protein (RIP) kinase family

    OpenAIRE

    Zhang, Duanwu; Lin, Juan; Han, Jiahuai

    2010-01-01

    Receptor-interacting protein (RIP) kinases are a group of threonine/serine protein kinases with a relatively conserved kinase domain but distinct non-kinase regions. A number of different domain structures, such as death and caspase activation and recruitment domain (CARD) domains, were found in different RIP family members, and these domains should be keys in determining the specific function of each RIP kinase. It is known that RIP kinases participate in different biological processes, incl...

  6. TH-302, a hypoxia-activated prodrug with broad in vivo preclinical combination therapy efficacy: optimization of dosing regimens and schedules.

    Science.gov (United States)

    Liu, Qian; Sun, Jessica D; Wang, Jingli; Ahluwalia, Dharmendra; Baker, Amanda F; Cranmer, Lee D; Ferraro, Damien; Wang, Yan; Duan, Jian-Xin; Ammons, W Steve; Curd, John G; Matteucci, Mark D; Hart, Charles P

    2012-06-01

    Subregional hypoxia is a common feature of tumors and is recognized as a limiting factor for the success of radiotherapy and chemotherapy. TH-302, a hypoxia-activated prodrug selectively targeting hypoxic regions of solid tumors, delivers a cytotoxic warhead to the tumor, while maintaining relatively low systemic toxicity. The antitumor activity, different dosing sequences, and dosing regimens of TH-302 in combination with commonly used conventional chemotherapeutics were investigated in human tumor xenograft models. Seven chemotherapeutic drugs (docetaxel, cisplatin, pemetrexed, irinotecan, doxorubicin, gemcitabine, and temozolomide) were tested in combination with TH-302 in eleven human xenograft models, including non-small cell lung cancer (NSCLC), colon cancer, prostate cancer, fibrosarcoma, melanoma, and pancreatic cancer. The antitumor activity of docetaxel, cisplatin, pemetrexed, irinotecan, doxorubicin, gemcitabine, and temozolomide was increased when combined with TH-302 in nine out of eleven models tested. Administration of TH-302 2-8 h prior to the other chemotherapeutics yielded superior efficacy versus other sequences tested. Simultaneous administration of TH-302 and chemotherapeutics increased toxicity versus schedules with dosing separations. In a dosing optimization study, TH-302 administered daily at 50 mg/kg intraperitoneally for 5 days per week in the H460 NSCLC model showed the optimal response with minimal toxicity. TH-302 enhances the activity of a wide range of conventional anti-neoplastic agents in a broad panel of in vivo xenograft models. These data highlight in vivo effects of schedule and order of drug administration in regimen efficacy and toxicity and have relevance to the design of human regimens incorporating TH-302.

  7. Janus Associated Kinases Inhibitors in the Pharmacological Thera

    Directory of Open Access Journals (Sweden)

    Daniela Santos1

    2017-01-01

    Full Text Available Janus associated kinases inhibitors are a new strategy for the treatment of different clinical conditions like immunologic, inflammatory and oncology disorders. The aim of this study was to perform a review of all Janus associated kinases inhibitors available in national and international pharmaceutical market, their therapeutic indications and adverse effects, and the potential indications for investigation of those already available in the pharmaceutical market. It was also performed a review of the main new Janus associated kinases inhibitors that are still in clinical research. A literature review was conducted by consulting the summary of product characteristics of Janus associated kinases inhibitors available in the pharmaceutical market and a research in the bibliographic database PubMed using the terms «JAK inhibitors», «Janus associated kinases inhibitors» and «Janus kinases inhibitors». Ninety-five publications were included in the present review, published from January 2014 to January 2015. Drug databases of the European Medicines Agency and United States Food and Drug Administration were also consulted to search for Janus associated kinases inhibitors authorized in clinical practice. Currently, ruxolitinib and tofacitinib are available in the pharmaceutical market and oclatinib is approved as a veterinary medicinal product. Both drugs approved for human use have major adverse effects at hematological and immunological levels, which enhance the importance of the pharmacist’s role in the monitoring of patients involved in these treatments. However, several molecules are in pre-clinical and clinical studies trying to prove its potential in the treatment of several immunologic, inflammatory and oncology disorders. Thus, it is still necessary to deepen the knowledge in this area in order to overcome the risks of therapy with these agents. These risks weighed against the benefits of its clinical use have compromised the progress of

  8. Gene expression profiling for nitric oxide prodrug JS-K to kill HL-60 myeloid leukemia cells.

    Science.gov (United States)

    Liu, Jie; Malavya, Swati; Wang, Xueqian; Saavedra, Joseph E; Keefer, Larry K; Tokar, Erik; Qu, Wei; Waalkes, Michael P; Shami, Paul J

    2009-07-01

    The nitric oxide (NO) prodrug JS-K is shown to have anticancer activity. To profile the molecular events associated with the anticancer effects of JS-K, HL-60 leukemia cells were treated with JS-K and subjected to microarray and real-time RT-PCR analysis. JS-K induced concentration- and time-dependent gene expression changes in HL-60 cells corresponding to the cytolethality effects. The apoptotic genes (caspases, Bax, and TNF-alpha) were induced, and differentiation-related genes (CD14, ITGAM, and VIM) were increased. For acute phase protein genes, some were increased (TP53, JUN) while others were suppressed (c-myc, cyclin E). The expression of anti-angiogenesis genes THBS1 and CD36 and genes involved in tumor cell migration such as tissue inhibitors of metalloproteinases, were also increased by JS-K. Confocal analysis confirmed key gene changes at the protein levels. Thus, multiple molecular events are associated with JS-K effects in killing HL-60, which could be molecular targets for this novel anticancer NO prodrug.

  9. Mesenchymal stromal cells retrovirally transduced with prodrug-converting genes are suitable vehicles for cancer gene therapy.

    Science.gov (United States)

    Ďuriniková, E; Kučerová, L; Matúšková, M

    2014-01-01

    Mesenchymal stem/stromal cells (MSC) possess a set of several fairly unique properties which make them ideally suitable both for cellular therapies and regenerative medicine. These include: relative ease of isolation, the ability to differentiate along mesenchymal and non-mesenchymal lineages in vitro and the ability to be extensively expanded in culture without a loss of differentiative capacity. MSC are not only hypoimmunogenic, but they mediate immunosuppression upon transplantation, and possess pronounced anti-inflammatory properties. They are able to home to damaged tissues, tumors, and metastases following systemic administration. The ability of homing holds big promise for tumor-targeted delivery of therapeutic agents. Viruses are naturally evolved vehicles efficiently transferring their genes into host cells. This ability made them suitable for engineering vector systems for the delivery of genes of interest. MSC can be retrovirally transduced with genes encoding prodrug-converting genes (suicide genes), which are not toxic per se, but catalyze the formation of highly toxic metabolites following the application of a nontoxic prodrug. The homing ability of MSC holds advantages compared to virus vehicles which display many shortcomings in effective delivery of the therapeutic agents. Gene therapies mediated by viruses are limited by their restricted ability to track cancer cells infiltrating into the surrounding tissue, and by their low migratory capacity towards tumor. Thus combination of cellular therapy and gene delivery is an attractive option - it protects the vector from immune surveillance, and supports targeted delivery of a therapeutic gene/protein to the tumor site.

  10. Efficacy of DA-7218, a new oxazolidinone prodrug, in the treatment of experimental actinomycetoma produced by Nocardia brasiliensis.

    Science.gov (United States)

    Espinoza-González, Nelly Alejandra; Welsh, Oliverio; de Torres, Noemi Waksman; Cavazos-Rocha, Norma; Ocampo-Candiani, Jorge; Said-Fernandez, Salvador; Lozano-Garza, Gerardo; Choi, Sung-Hak; Vera-Cabrera, Lucio

    2008-01-11

    Two recently synthesized oxazolidinones: (R)-3-(4-(2-(2-methyltetrazol-5-yl)-pyridin-5-yl)-3-fluorophenyl)-5-hydroxymethyloxazolidin-2-one (DA-7157) and its corresponding pro-drug (R)-3-(4-(2-(2-methyltetrazol-5-yl)-pyridin-5-yl)-3-fluorophenyl)-2-oxo-5-oxazolidinyl) methyl disodium phosphate (DA-7218), have shown very good activity against several Gram positive bacteria, including Nocardia and Mycobacterium. In the present work we evaluated the therapeutic in vivo effects of DA-7218 on Nocardia brasiliensis. We first determined the plasma concentration of the prodrug in BALB/c mice using several doses and then tested its activity in an in vivo experimental actinomycetoma murine model. At the end of treatment, there was a statistically significant difference between the three drug receiving groups (25, 12.5 and 5 mg/kg) and the control group(saline solution) (p=0.001), proving that DA-7218 is effective for the treatment of experimental murine actinomycetoma. This compound could be a potential option for patients affected with mycetoma by Nocardia brasiliensis.

  11. Efficacy of DA-7218, a New Oxazolidinone Prodrug, in the Treatment of Experimental Actinomycetoma Produced by Nocardia brasiliensis

    Directory of Open Access Journals (Sweden)

    Lucio Vera-Cabrera

    2008-01-01

    Full Text Available Two recently synthesized oxazolidinones: (R-3-(4-(2-(2-methyltetrazol-5-yl-pyridin-5-yl-3-fluorophenyl-5-hydroxymethyloxazolidin-2-one (DA-7157 and itscorresponding pro-drug (R-3-(4-(2-(2-methyltetrazol-5-yl-pyridin-5-yl-3-fluorophenyl-2-oxo-5-oxazolidinyl methyl disodium phosphate (DA-7218, have shown very goodactivity against several Gram positive bacteria, including Nocardia and Mycobacterium. Inthe present work we evaluated the therapeutic in vivo effects of DA-7218 on Nocardiabrasiliensis. We first determined the plasma concentration of the prodrug in BALB/c miceusing several doses and then tested its activity in an in vivo experimental actinomycetomamurine model. At the end of treatment, there was a statistically significant differencebetween the three drug receiving groups (25, 12.5 and 5 mg/kg and the control group(saline solution (p=0.001, proving that DA-7218 is effective for the treatment of experimental murine actinomycetoma. This compound could be a potential option forpatients affected with mycetoma by Nocardia brasiliensis.

  12. Aspirin Augments IgE-Mediated Histamine Release from Human Peripheral Basophils via Syk Kinase Activation

    Directory of Open Access Journals (Sweden)

    Hiroaki Matsuo

    2013-01-01

    Conclusions: Aspirin enhanced histamine release from basophils via increased Syk kinase activation, and that the augmentation of histamine release by NSAIDs or FAs may be one possible cause of worsening symptoms in patients with chronic urticaria and FDEIA.

  13. In vitro optimization of non-small cell lung cancer activity with troxacitabine, L-1,3-dioxolane-cytidine, prodrugs

    NARCIS (Netherlands)

    Radi, Marco; Adema, Auke D.; Daft, Jonathan R.; Cho, Jong H.; Hoebe, Eveline K.; Alexander, Lou-Ella M. M.; Peters, Godefridus J.; Chu, Chung K.

    2007-01-01

    l-1,3-Dioxolane-cytidine, a potent anticancer agent against leukemia, has limited efficacy against solid tumors, perhaps due to its hydrophilicity. Herein, a library of prodrugs were synthesized to optimize in vitro antitumor activity against non-small cell lung cancer. N4-Substituted fatty acid

  14. The Moderating Role of Parental Monitoring on the Influence of Peer Pro-Drug Norms on Alcohol and Cigarette Use among Adolescents in Mexico

    Science.gov (United States)

    Becerra, David; Castillo, Jason T.; Ayón, Cecilia; Blanchard, Kelly N.

    2014-01-01

    This study utilized data drawn from a study of 980 adolescents living in Tijuana, Mexico, in February 2009 to examine whether parental monitoring had a moderating impact on the influence of peer pro-drug norms on lifetime and past-30-day alcohol and cigarette use among a group of adolescents living along the United States-Mexico border. The…

  15. Computational modeling and in-vitro/in-silico correlation of phospholipid-based prodrugs for targeted drug delivery in inflammatory bowel disease

    Science.gov (United States)

    Dahan, Arik; Markovic, Milica; Keinan, Shahar; Kurnikov, Igor; Aponick, Aaron; Zimmermann, Ellen M.; Ben-Shabat, Shimon

    2017-11-01

    Targeting drugs to the inflamed intestinal tissue(s) represents a major advancement in the treatment of inflammatory bowel disease (IBD). In this work we present a powerful in-silico modeling approach to guide the molecular design of novel prodrugs targeting the enzyme PLA2, which is overexpressed in the inflamed tissues of IBD patients. The prodrug consists of the drug moiety bound to the sn-2 position of phospholipid (PL) through a carbonic linker, aiming to allow PLA2 to release the free drug. The linker length dictates the affinity of the PL-drug conjugate to PLA2, and the optimal linker will enable maximal PLA2-mediated activation. Thermodynamic integration and Weighted Histogram Analysis Method (WHAM)/Umbrella Sampling method were used to compute the changes in PLA2 transition state binding free energy of the prodrug molecule (ΔΔGtr) associated with decreasing/increasing linker length. The simulations revealed that 6-carbons linker is the optimal one, whereas shorter or longer linkers resulted in decreased PLA2-mediated activation. These in-silico results were shown to be in excellent correlation with experimental in-vitro data. Overall, this modern computational approach enables optimization of the molecular design of novel prodrugs, which may allow targeting the free drug specifically to the diseased intestinal tissue of IBD patients.

  16. Design and in vitro evaluation of self-assembled indometacin prodrug nanoparticles for sustained/controlled release and reduced normal cell toxicity

    Science.gov (United States)

    Lin, Jinyan; Pan, Zhou; Song, Liang; Zhang, Yanmei; Li, Yang; Hou, Zhenqing; Lin, Changjian

    2017-12-01

    Despite the great efficacy of indomethacin (IND) as an anti-inflammatory agent, its clinical translation has been obstructed by the water insolubility, severe side effects, and exceedingly low bioavailability. Indomethacin prodrug-based nanoparticles (NPs) combining the strengths of both nanotechnology and prodrugs that might overcome this crucial problem are presented. Here, using the carbodiimide-mediated couple reaction, IND was conjugated to clinically approved poly(ethylene glycol) (PEG) polymer via peptide linkage that was cleavaged in the presence of cathepsin B, which was significantly induced after inflammatory. The synthesized IND-PEG-IND conjugate was characterized by UV-vis, FTIR, 1H NMR, XRD, and MALDI-TOF-MS analyses. For its intrinsic amphiphilic property, the IND prodrug self-assembled into NPs in aqueous solution and served two roles-as an anti-inflammatory prodrug and a drug carrier. The constructed IND-PEG-IND NPs had naoscaled particle size of approximately 80 nm, negative surface, spherical shape, good water-dispersity, and high and fixed drug-loading content of 20.1 wt%. In addition, IND-PEG-IND NPs demonstrated sustained and cathepsin B-controlled drug release behavior. More importantly, IND-PEG-IND NPs significantly reduced the acute totoxicity agaist normal osteoblast cells and displayed the more potent anti-inflammatory effect against macrophage cells compared to the free IND. Taken together, the nanoprodrug might exhibit increased potency for nanomedicine-prospective therapeutic use in clinical treatement of implant inflammatory diseases.

  17. Construction of dual-functional polymer nanomaterials with near-infrared fluorescence imaging and polymer prodrug by RAFT-mediated aqueous dispersion polymerization.

    Science.gov (United States)

    Tian, Chun; Niu, Jinyun; Wei, Xuerui; Xu, Yujie; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2018-05-31

    The performance of functional polymer nanomaterials is a vigorously discussed topic in polymer science. We devoted ourselves to investigating polymer nanomaterials based on near-infrared (NIR) fluorescence imaging and polymer prodrug in this study. Aza-boron dipyrromethene (BODIPY) is an important organic dye, having characteristics such as environmental resistance, light resistance, high molar extinction coefficient, and fluorescence quantum yield. We incorporated it into our target monomer, which can be polymerized without changing its parent structure in a polar solvent and copolymerized with water-soluble monomer to improve the solubility of the dye in an aqueous solution. At the same time, the hydrophobic drug camptothecin (CPT) was designed as a prodrug monomer, and the polymeric nanoparticles (NPs) with NIR fluorescence imaging and prodrug were synthesized in situ in reversible addition-fragmentation chain transfer (RAFT)-mediated aqueous dispersion polymerization. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed the final uniform size of the dual-functional polymeric NPs morphology. The dual-functional polymeric NPs had a strong absorption and emission signal in the NIR region (>650 nm) based on the fluorescence tests. In consideration of the long-term biological toxicity, confocal laser scanning microscopy (CLSM) results indicated that the dual-functional NPs with controlled drug content exhibited effective capability of killing HeLa cells. In addition, in vivo imaging of the dual-functional NPs was observed in real time, and the fluorescent signals clearly demonstrated the dynamic process of prodrug transfer.

  18. TRANSDERMAL ADMINISTRATION OF THE DOPAMINE AGONIST N-0437 AND 7 ESTER PRODRUGS - COMPARISON WITH ORAL-ADMINISTRATION IN THE 6-OHDA TURNING MODEL

    NARCIS (Netherlands)

    DENDAAS, [No Value; TEPPER, PG; ROLLEMA, H; HORN, AS

    1990-01-01

    The potent and selective D2-agonist N-0437 [2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin] undergoes considerable first-pass metabolism after oral administration due to glucuronidation of the phenolic group. In an attempt to improve its bioavailability, seven ester prodrugs of N-0437 were

  19. Polymorphs and prodrugs and salts (oh my!: an empirical analysis of "secondary" pharmaceutical patents.

    Directory of Open Access Journals (Sweden)

    Amy Kapczynski

    Full Text Available BACKGROUND: While there has been much discussion by policymakers and stakeholders about the effects of "secondary patents" on the pharmaceutical industry, there is no empirical evidence on their prevalence or determinants. Characterizing the landscape of secondary patents is important in light of recent court decisions in the U.S. that may make them more difficult to obtain, and for developing countries considering restrictions on secondary patents. METHODOLOGY/PRINCIPAL FINDINGS: We read the claims of the 1304 Orange Book listed patents on all new molecular entities approved in the U.S. between 1988 and 2005, and coded the patents as including chemical compound claims (claims covering the active molecule itself and/or one of several types of secondary claims. We distinguish between patents with any secondary claims, and those with only secondary claims and no chemical compound claims ("independent" secondary patents. We find that secondary claims are common in the pharmaceutical industry. We also show that independent secondary patents tend to be filed and issued later than chemical compound patents, and are also more likely to be filed after the drug is approved. When present, independent formulation patents add an average of 6.5 years of patent life (95% C.I.: 5.9 to 7.3 years, independent method of use patents add 7.4 years (95% C.I.: 6.4 to 8.4 years, and independent patents on polymorphs, isomers, prodrug, ester, and/or salt claims add 6.3 years (95% C.I.: 5.3 to 7.3 years. We also provide evidence that late-filed independent secondary patents are more common for higher sales drugs. CONCLUSIONS/SIGNIFICANCE: Policies and court decisions affecting secondary patenting are likely to have a significant impact on the pharmaceutical industry. Secondary patents provide substantial additional patent life in the pharmaceutical industry, at least nominally. Evidence that they are also more common for best-selling drugs is consistent with accounts of

  20. Pyruvate sensitizes pancreatic tumors to hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Wojtkowiak, Jonathan W; Cornnell, Heather C; Matsumoto, Shingo; Saito, Keita; Takakusagi, Yoichi; Dutta, Prasanta; Kim, Munju; Zhang, Xiaomeng; Leos, Rafael; Bailey, Kate M; Martinez, Gary; Lloyd, Mark C; Weber, Craig; Mitchell, James B; Lynch, Ronald M; Baker, Amanda F; Gatenby, Robert A; Rejniak, Katarzyna A; Hart, Charles; Krishna, Murali C; Gillies, Robert J

    2015-01-01

    Hypoxic niches in solid tumors harbor therapy-resistant cells. Hypoxia-activated prodrugs (HAPs) have been designed to overcome this resistance and, to date, have begun to show clinical efficacy. However, clinical HAPs activity could be improved. In this study, we sought to identify non-pharmacological methods to acutely exacerbate tumor hypoxia to increase TH-302 activity in pancreatic ductal adenocarcinoma (PDAC) tumor models. Three human PDAC cell lines with varying sensitivity to TH-302 (Hs766t > MiaPaCa-2 > SU.86.86) were used to establish PDAC xenograft models. PDAC cells were metabolically profiled in vitro and in vivo using the Seahorse XF system and hyperpolarized (13)C pyruvate MRI, respectively, in addition to quantitative immunohistochemistry. The effect of exogenous pyruvate on tumor oxygenation was determined using electroparamagnetic resonance (EPR) oxygen imaging. Hs766t and MiaPaCa-2 cells exhibited a glycolytic phenotype in comparison to TH-302 resistant line SU.86.86. Supporting this observation is a higher lactate/pyruvate ratio in Hs766t and MiaPaCa xenografts as observed during hyperpolarized pyruvate MRI studies in vivo. Coincidentally, response to exogenous pyruvate both in vitro (Seahorse oxygen consumption) and in vivo (EPR oxygen imaging) was greatest in Hs766t and MiaPaCa models, possibly due to a higher mitochondrial reserve capacity. Changes in oxygen consumption and in vivo hypoxic status to pyruvate were limited in the SU.86.86 model. Combination therapy of pyruvate plus TH-302 in vivo significantly decreased tumor growth and increased survival in the MiaPaCa model and improved survival in Hs766t tumors. Using metabolic profiling, functional imaging, and computational modeling, we show improved TH-302 activity by transiently increasing tumor hypoxia metabolically with exogenous pyruvate. Additionally, this work identified a set of biomarkers that may be used clinically to predict which tumors will be most responsive to

  1. Hierarchical modeling of activation mechanisms in the ABL and EGFR kinase domains: thermodynamic and mechanistic catalysts of kinase activation by cancer mutations.

    Directory of Open Access Journals (Sweden)

    Anshuman Dixit

    2009-08-01

    and the enhanced stabilization of the active kinase form. The results of this study reconcile current experimental data with insights from theoretical approaches, pointing to general mechanistic aspects of activating transitions in protein kinases.

  2. Sodium phenylbutyrate enhances astrocytic neurotrophin synthesis via protein kinase C (PKC)-mediated activation of cAMP-response element-binding protein (CREB): implications for Alzheimer disease therapy.

    Science.gov (United States)

    Corbett, Grant T; Roy, Avik; Pahan, Kalipada

    2013-03-22

    Neurotrophins, such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), are believed to be genuine molecular mediators of neuronal growth and homeostatic synapse activity. However, levels of these neurotrophic factors decrease in different brain regions of patients with Alzheimer disease (AD). Induction of astrocytic neurotrophin synthesis is a poorly understood phenomenon but represents a plausible therapeutic target because neuronal neurotrophin production is aberrant in AD and other neurodegenerative diseases. Here, we delineate that sodium phenylbutyrate (NaPB), a Food and Drug Administration-approved oral medication for hyperammonemia, induces astrocytic BDNF and NT-3 expression via the protein kinase C (PKC)-cAMP-response element-binding protein (CREB) pathway. NaPB treatment increased the direct association between PKC and CREB followed by phosphorylation of CREB (Ser(133)) and induction of DNA binding and transcriptional activation of CREB. Up-regulation of markers for synaptic function and plasticity in cultured hippocampal neurons by NaPB-treated astroglial supernatants and its abrogation by anti-TrkB blocking antibody suggest that NaPB-induced astroglial neurotrophins are functionally active. Moreover, oral administration of NaPB increased the levels of BDNF and NT-3 in the CNS and improved spatial learning and memory in a mouse model of AD. Our results highlight a novel neurotrophic property of NaPB that may be used to augment neurotrophins in the CNS and improve synaptic function in disease states such as AD.

  3. [Effect of inhibitors serine/threonine protein kinases and protein phosphatases on mitosis progression of synchronized tobacco by-2 cells].

    Science.gov (United States)

    Sheremet, Ia A; Emets, A I; Azmi, A; Vissenberg, K; Verbelen, J-P; Blium, Ia B

    2012-01-01

    In order to investigate the role of various serine/ threonine protein kinases and protein phosphatases in the regulation of mitosis progression in plant cells the influence of cyclin-dependent (olomoucine) and Ca2+ -calmodulin-dependent (W7) protein kinases inhibitors, as well as protein kinase C inhibitors (H7 and staurosporine) and protein phosphatases inhibitor (okadaic acid) on mitosis progression in synchronized tobacco BY-2 cells has been studied. It was found that BY-2 culture treatment with inhibitors of cyclin dependent protein kinases and protein kinase C causes prophase delay, reduces the mitotic index and displaces of mitotic peak as compare with control cells. Inhibition of Ca2+ -calmodulin dependent protein kinases enhances the cell entry into prophase and delays their exit from mitosis. Meanwhile inhibition of serine/threonine protein phosphatases insignificantly enhances of synchronized BY-2 cells entering into all phases of mitosis.

  4. The progesterone-induced enhancement of object recognition memory consolidation involves activation of the extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR) pathways in the dorsal hippocampus

    Science.gov (United States)

    Orr, Patrick T.; Rubin, Amanda J.; Fan, Lu; Kent, Brianne A.; Frick, Karyn M.

    2012-01-01

    Although much recent work has elucidated the biochemical mechanisms underlying the modulation of memory by 17β-estradiol, little is known about the signaling events through which progesterone (P) regulates memory. We recently demonstrated that immediate post-training infusion of P into the dorsal hippocampus enhances object recognition memory consolidation in young ovariectomized female mice (Orr et al., 2009). The goal of the present study was to identify the biochemical alterations that might underlie this mnemonic enhancement. We hypothesized that the P-induced enhancement of object recognition would be dependent on activation of the ERK and mTOR pathways. In young ovariectomized mice, we found that bilateral dorsal hippocampal infusion of P significantly increased levels of phospho-p42 ERK and the mTOR substrate S6K in the dorsal hippocampus 5 minutes after infusion. Phospho-p42 ERK levels were downregulated 15 minutes after infusion and returned to baseline 30 minutes after infusion, suggesting a biphasic effect of P on ERK activation. Dorsal hippocampal ERK and mTOR activation were necessary for P to facilitate memory consolidation, as suggested by the fact that inhibitors of both pathways infused into the dorsal hippocampus immediately after training blocked the P-induced enhancement of object recognition. Collectively, these data provide the first demonstration that the ability of P to enhance memory consolidation depends on the rapid activation of cell signaling and protein synthesis pathways in the dorsal hippocampus. PMID:22265866

  5. LOK is a major ERM kinase in resting lymphocytes and regulates cytoskeletal rearrangement through ERM phosphorylation.

    Science.gov (United States)

    Belkina, Natalya V; Liu, Yin; Hao, Jian-Jiang; Karasuyama, Hajime; Shaw, Stephen

    2009-03-24

    ERM (ezrin-radixin-moesin) proteins mediate linkage of actin cytoskeleton to plasma membrane in many cells. ERM activity is regulated in part by phosphorylation at a C-terminal threonine, but the identity of ERM kinases is unknown in lymphocytes and incompletely defined in other mammalian cells. Our studies show that lymphocyte-oriented kinase (LOK) is an ERM kinase in vitro and in vivo. Mass spectrometric analysis indicates LOK is abundant at the lymphocyte plasma membrane and immunofluorescence studies show LOK enrichment at the plasma membrane near ERM. In vitro peptide specificity analyses characterize LOK as a basophilic kinase whose optimal substrate sequence resembles the ERM site, including unusual preference for tyrosine at P-2. LOK's activity on moesin peptide and protein was comparable to reported ERM kinases ROCK and PKC but unlike them LOK displayed preferential specificity for moesin compared to traditional basophilic kinase substrates. Two genetic approaches demonstrate a role for LOK in ERM phosphorylation: cell transfection with LOK kinase domain augments ERM phosphorylation and lymphocytes from LOK knockout mice have >50% reduction in ERM phosphorylation. The findings on localization and specificity argue that LOK is a direct ERM kinase. The knockout mice have normal hematopoietic cell development but notably lymphocyte migration and polarization in response to chemokine are enhanced. These functional alterations fit the current understanding of the role of ERM phosphorylation in regulating cortical reorganization. Thus, these studies identify a new ERM kinase of importance in lymphocytes and confirm the role of ERM phosphorylation in regulating cell shape and motility.

  6. JS-K, a nitric oxide prodrug, induces cytochrome c release and caspase activation in HL-60 myeloid leukemia cells.

    Science.gov (United States)

    Udupi, Vidya; Yu, Margaret; Malaviya, Swati; Saavedra, Joseph E; Shami, Paul J

    2006-10-01

    Nitric oxide (NO) induces differentiation and apoptosis in acute myelogenous leukemia (AML) cells. The NO prodrug O2-(2,4-dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate, or JS-K, has potent antileukemic activity. JS-K induces apoptosis in HL-60 cells by a caspase-dependent mechanism. The purpose of this study was to determine the pathway through which JS-K induces apoptosis. We show that JS-K alters mitochondrial membrane potential (DeltaPsim) and induces cytochrome c release from mitochondria into the cytoplasm. Treatment with JS-K resulted in activation of Caspase (Casp) 9, Casp 3 and Casp 8. JS-K constitutes a promising lead for a new class of anti-leukemic agents.

  7. Enhanced expression of WD repeat-containing protein 35 (WDR35 stimulated by domoic acid in rat hippocampus: involvement of reactive oxygen species generation and p38 mitogen-activated protein kinase activation

    Directory of Open Access Journals (Sweden)

    Tsunekawa Koji

    2013-01-01

    Full Text Available Abstract Background Domoic acid (DA is an excitatory amino acid analogue of kainic acid (KA that acts via activation of glutamate receptors to elicit a rapid and potent excitotoxic response, resulting in neuronal cell death. Recently, DA was shown to elicit reactive oxygen species (ROS production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK in vitro. We have reported that WDR35, a WD-repeat protein, may mediate apoptosis in several animal models. In the present study, we administered DA to rats intraperitoneally, then used liquid chromatography/ion trap tandem mass spectrometry (LC-MS/MS to identify and quantify DA in the brains of the rats and performed histological examinations of the hippocampus. We further investigated the potential involvement of glutamate receptors, ROS, p38 MAPK, and WDR35 in DA-induced toxicity in vivo. Results Our results showed that intraperitoneally administered DA was present in the brain and induced neurodegenerative changes including apoptosis in the CA1 region of the hippocampus. DA also increased the expression of WDR35 mRNA and protein in a dose- and time-dependent manner in the hippocampus. In experiments using glutamate receptor antagonists, the AMPA/KA receptor antagonist NBQX significantly attenuated the DA-induced increase in WDR35 protein expression, but the NMDA receptor antagonist MK-801 did not. In addition, the radical scavenger edaravone significantly attenuated the DA-induced increase in WDR35 protein expression. Furthermore, NBQX and edaravone significantly attenuated the DA-induced increase in p38 MAPK phosphorylation. Conclusion In summary, our results indicated that DA activated AMPA/KA receptors and induced ROS production and p38 MAPK phosphorylation, resulting in an increase in the expression of WDR35 in vivo.

  8. Biological and Mechanistic Characterization of Novel Prodrugs of Green Tea Polyphenol Epigallocatechin Gallate Analogs in Human Leiomyoma Cell Lines.

    Science.gov (United States)

    Ahmed, Reda Saber Ibrahim; Liu, Gang; Renzetti, Andrea; Farshi, Pershang; Yang, Huanjie; Soave, Claire; Saed, Ghassan; El-Ghoneimy, Ashraf Ahmed; El-Banna, Hossny Awad; Foldes, Robert; Chan, Tak-Hang; Dou, Q Ping

    2016-10-01

    Uterine fibroids (leiomyomas) are very common benign tumors grown on the smooth muscle layer of the uterus, present in up to 75% of reproductive-age women and causing significant morbidity in a subset of this population. Although the etiology and biology of uterine fibroids are unclear, strong evidence supports that cell proliferation, angiogenesis and fibrosis are involved in their formation and growth. Currently the only cure for uterine fibroids is hysterectomy; the available alternative therapies have limitations. Thus, there is an urgent need for developing a novel strategy for treating this condition. The green tea polyphenol epigallocatechin gallate (EGCG) inhibits the growth of uterine leiomyoma cells in vitro and in vivo, and the use of a green tea extract (containing 45% EGCG) has demonstrated clinical activity without side effects in women with symptomatic uterine fibroids. However, EGCG has a number of shortcomings, including low stability, poor bioavailability, and high metabolic transformations under physiological conditions, presenting challenges for its development as a therapeutic agent. We developed a prodrug of EGCG (Pro-EGCG or 1) which shows increased stability, bioavailability and biological activity in vivo as compared to EGCG. We also synthesized prodrugs of EGCG analogs, compounds 2a and 4a, in order to potentially reduce their susceptibility to methylation/inhibition by catechol-O-methyltransferase. Here, we determined the effect of EGCG, Pro-EGCG, and 2a and 4a on cultured human uterine leiomyoma cells, and found that 2a and 4a have potent antiproliferative, antiangiogenic, and antifibrotic activities. J. Cell. Biochem. 117: 2357-2369, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. Prodrug encapsulated albumin nanoparticles as an alternative approach to manifest anti-proliferative effects of suicide gene therapy

    International Nuclear Information System (INIS)

    Tirkey, Bulbul; Bhushan, Bharat; Uday Kumar, S.; Gopinath, P.

    2017-01-01

    Conventional anticancer agents are associated with limited therapeutic efficacy and substantial nonspecific cytotoxicity. Thus, there is an imminent need for an alternative approach that can specifically annihilate the cancer cells with minimal side effects. Among such alternative approaches, CD::UPRT (cytosine deaminase uracil phosphoribosyl transferase) suicide gene therapy has tremendous potential due to its high efficacy. Prodrug 5-Fluorocytosine (5-FC) used in combination with CD::UPRT suicide gene suffers from limited solubility which subsequently leads to decline in therapeutic efficacy. In order to overcome this, 5-FC encapsulated bovine serum albumin nanoparticles (BSA-5-FC NPs) were prepared in this work by desolvation method. Physico-chemical characterizations studies revealed amorphous nature of BSA-5-FC NPs with uniform spherical morphology. Apart from increase in solubility, encapsulated 5-FC followed slow and sustained release profile. Suicide gene expressing stable clone of L-132 cells were adapted for investigating therapeutic potential of BSA-5-FC NPs. These nanoparticles were readily taken up by the cells in a concentration dependent manner and subsequently manifested apoptosis, which was further confirmed by morphological examination and gene expression analysis. These findings clearly illustrate that CD::UPRT suicide gene therapy can be efficiently utilized in combination with this nanosystem for improved suicide gene therapy and tumor eradication. - Highlights: • In this work, BSA-5-FC NPs has been prepared to achieve its sustained release and also facilitate its uptake by cells. • A protein based system has been realized for the first time to deliver prodrug for cancer therapy. • Physico-chemical characterizations further validate the formation of spherical, monodispersed and stable nanoparticles. • The therapeutic efficacy of BSA-5-FC NPs has been validated against CD::UPRT expressing stable cells.

  10. Prodrug encapsulated albumin nanoparticles as an alternative approach to manifest anti-proliferative effects of suicide gene therapy

    Energy Technology Data Exchange (ETDEWEB)

    Tirkey, Bulbul [Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Bhushan, Bharat; Uday Kumar, S. [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Gopinath, P., E-mail: pgopifnt@iitr.ernet.in [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India)

    2017-04-01

    Conventional anticancer agents are associated with limited therapeutic efficacy and substantial nonspecific cytotoxicity. Thus, there is an imminent need for an alternative approach that can specifically annihilate the cancer cells with minimal side effects. Among such alternative approaches, CD::UPRT (cytosine deaminase uracil phosphoribosyl transferase) suicide gene therapy has tremendous potential due to its high efficacy. Prodrug 5-Fluorocytosine (5-FC) used in combination with CD::UPRT suicide gene suffers from limited solubility which subsequently leads to decline in therapeutic efficacy. In order to overcome this, 5-FC encapsulated bovine serum albumin nanoparticles (BSA-5-FC NPs) were prepared in this work by desolvation method. Physico-chemical characterizations studies revealed amorphous nature of BSA-5-FC NPs with uniform spherical morphology. Apart from increase in solubility, encapsulated 5-FC followed slow and sustained release profile. Suicide gene expressing stable clone of L-132 cells were adapted for investigating therapeutic potential of BSA-5-FC NPs. These nanoparticles were readily taken up by the cells in a concentration dependent manner and subsequently manifested apoptosis, which was further confirmed by morphological examination and gene expression analysis. These findings clearly illustrate that CD::UPRT suicide gene therapy can be efficiently utilized in combination with this nanosystem for improved suicide gene therapy and tumor eradication. - Highlights: • In this work, BSA-5-FC NPs has been prepared to achieve its sustained release and also facilitate its uptake by cells. • A protein based system has been realized for the first time to deliver prodrug for cancer therapy. • Physico-chemical characterizations further validate the formation of spherical, monodispersed and stable nanoparticles. • The therapeutic efficacy of BSA-5-FC NPs has been validated against CD::UPRT expressing stable cells.

  11. The bumetanide prodrug BUM5, but not bumetanide, potentiates the antiseizure effect of phenobarbital in adult epileptic mice.

    Science.gov (United States)

    Erker, Thomas; Brandt, Claudia; Töllner, Kathrin; Schreppel, Philipp; Twele, Friederike; Schidlitzki, Alina; Löscher, Wolfgang

    2016-05-01

    The loop diuretic bumetanide has been reported to potentiate the antiseizure activity of phenobarbital in rodent models of neonatal seizures, most likely as a result of inhibition of the chloride importer Na-K-Cl cotransporter isoform 1 (NKCC1) in the brain. In view of the intractability of neonatal seizures, the preclinical findings prompted a clinical trial in neonates on bumetanide as an add-on to phenobarbital, which, however, had to be terminated because of ototoxicity and lack of efficacy. We have recently shown that bumetanide penetrates only poorly into the brain, so that we developed lipophilic prodrugs such as BUM5, the N,N-dimethylaminoethylester of bumetanide, which penetrate more easily into the brain and are converted to bumetanide. In the present study, we used a new strategy to test whether BUM5 is more potent than bumetanide in potentiating the antiseizure effect of phenobarbital. Adult mice were made epileptic by pilocarpine, and the antiseizure effects of bumetanide, BUM5, and phenobarbital alone or in combination were determined by the maximal electroshock seizure threshold test. In nonepileptic mice, only phenobarbital exerted seizure threshold-increasing activity, and this was not potentiated by the NKCC1 inhibitors. In contrast, a marked potentiation of phenobarbital by BUM5, but not bumetanide, was determined in epileptic mice. Thus, bumetanide is not capable of potentiating phenobarbital's antiseizure effect in an adult mouse model, which, however, can be overcome by using the prodrug BUM5. These data substantiate that BUM5 is a promising tool compound for target validation and proof-of-concept studies on the role of NKCC1 in brain diseases. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  12. L-4F Inhibits Oxidized Low-density Lipoprotein-induced Inflammatory Adipokine Secretion via Cyclic AMP/Protein Kinase A-CCAAT/Enhancer Binding Protein β Signaling Pathway in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Xiang-Zhu Xie

    2016-01-01

    Conclusions: OxLDL induces C/EBPβ protein synthesis in a time-dependent manner and enhances MCP-1 secretion and expression in 3T3-L1 adipocytes. L-4F dose-dependently counterbalances the pro-inflammatory effect of oxLDL, and cyclic AMP/PKA-C/EBPβ signaling pathway may participate in it.

  13. Chitin and stress induced protein kinase activation

    DEFF Research Database (Denmark)

    Kenchappa, Chandra Shekar; Azevedo da Silva, Raquel; Bressendorff, Simon

    2017-01-01

    The assays described here are pertinent to protein kinase studies in any plant. They include an immunoblot phosphorylation/activation assay and an in-gel activity assay for MAP kinases (MPKs) using the general protein kinase substrate myelin basic protein. They also include a novel in-gel peptide...... substrate assay for Snf1-related kinase family 2 members (SnRK2s). This kinase family-specific assay overcomes some limitations of in-gel assays and permits the identification of different types of kinase activities in total protein extracts....

  14. The In-Situ One-Step Synthesis of a PDC Macromolecular Pro-Drug and the Fabrication of a Novel Core-Shell Micell.

    Science.gov (United States)

    Yu, Cui-Yun; Yang, Sa; Li, Zhi-Ping; Huang, Can; Ning, Qian; Huang, Wen; Yang, Wen-Tong; He, Dongxiu; Sun, Lichun

    2016-01-01

    The development of slow release nano-sized carriers for efficient antineoplastic drug delivery with a biocompatible and biodegradable pectin-based macromolecular pro-drug for tumor therapy has been reported in this study. Pectin-doxorubicin conjugates (PDC), a macromolecular pro-drug, were prepared via an amide condensation reaction, and a novel amphiphilic core-shell micell based on a PDC macromolecular pro-drug (PDC-M) was self-assembled in situ, with pectin as the hydrophilic shell and doxorubicin (DOX) as the hydrophobic core. Then the chemical structure of the PDC macromolecular pro-drug was identified by both Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy ((1)H-NMR), and proved that doxorubicin combined well with the pectin and formed macromolecular pro-drug. The PDC-M were observed to have an unregularly spherical shape and were uniform in size by scanning electron microscopy (SEM). The average particle size of PDC-M, further measured by a Zetasizer nanoparticle analyzer (Nano ZS, Malvern Instruments), was about 140 nm. The encapsulation efficiency and drug loading were 57.82% ± 3.7% (n = 3) and 23.852% ±2.3% (n = 3), respectively. The in vitro drug release behaviors of the resulting PDC-M were studied in a simulated tumor environment (pH 5.0), blood (pH 7.4) and a lysosome media (pH 6.8), and showed a prolonged slow release profile. Assays for antiproliferative effects and flow cytometry of the resulting PDC-M in HepG2 cell lines demonstrated greater properties of delayed and slow release as compared to free DOX. A cell viability study against endothelial cells further revealed that the resulting PDC-M possesses excellent cell compatibilities and low cytotoxicities in comparison with that of the free DOX. Hemolysis activity was investigated in rabbits, and the results also demonstrated that the PDC-M has greater compatibility in comparison with free DOX. This shows that the resulting PDC-M can ameliorate the

  15. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    International Nuclear Information System (INIS)

    Slot Christiansen, Louise; Egeblad, Louise; Munch-Petersen, Birgitte; Piškur, Jure; Knecht, Wolfgang

    2015-01-01

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been tested as enzymes for suicide gene therapy. The tomato thymidine kinase 1 (ToTK1) is a dNK that has been selected for its in vitro kinetic properties and then successfully been tested in vivo for the treatment of malignant glioma. We present the selection of two improved variants of ToTK1 generated by random protein engineering for suicide gene therapy with the NA azidothymidine (AZT). We describe their selection, recombinant production and a subsequent kinetic and biochemical characterization. Their improved performance in killing of E. coli KY895 is accompanied by an increase in specificity for the NA AZT over the natural substrate thymidine as well as a decrease in inhibition by dTTP, the end product of the nucleoside salvage pathway for thymidine. The understanding of the enzymatic properties improving the variants efficacy is instrumental to further develop dNKs for use in suicide gene therapy

  16. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    Energy Technology Data Exchange (ETDEWEB)

    Slot Christiansen, Louise [Department of Biology, Lund University, Lund 22362 (Sweden); Lund Protein Production Platform, Lund University, Lund 22362 (Sweden); Egeblad, Louise [Lund Protein Production Platform, Lund University, Lund 22362 (Sweden); Munch-Petersen, Birgitte [Department of Science, Systems and Models, Roskilde University, Roskilde 4000 (Denmark); Piškur, Jure [Department of Biology, Lund University, Lund 22362 (Sweden); Knecht, Wolfgang, E-mail: Louise.Slot_Christiansen@biol.lu.se [Department of Biology, Lund University, Lund 22362 (Sweden); Lund Protein Production Platform, Lund University, Lund 22362 (Sweden)

    2015-06-08

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been tested as enzymes for suicide gene therapy. The tomato thymidine kinase 1 (ToTK1) is a dNK that has been selected for its in vitro kinetic properties and then successfully been tested in vivo for the treatment of malignant glioma. We present the selection of two improved variants of ToTK1 generated by random protein engineering for suicide gene therapy with the NA azidothymidine (AZT). We describe their selection, recombinant production and a subsequent kinetic and biochemical characterization. Their improved performance in killing of E. coli KY895 is accompanied by an increase in specificity for the NA AZT over the natural substrate thymidine as well as a decrease in inhibition by dTTP, the end product of the nucleoside salvage pathway for thymidine. The understanding of the enzymatic properties improving the variants efficacy is instrumental to further develop dNKs for use in suicide gene therapy.

  17. Simple fluorescence-based detection of protein kinase A activity using a molecular beacon probe.

    Science.gov (United States)

    Ma, Changbei; Lv, Xiaoyuan; Wang, Kemin; Jin, Shunxin; Liu, Haisheng; Wu, Kefeng; Zeng, Weimin

    2017-11-02

    Protein kinase A was detected by quantifying the amount of ATP used after a protein kinase reaction. The ATP assay was performed using the T4 DNA ligase and a molecular beacon (MB). In the presence of ATP, DNA ligase catalyzed the ligation of short DNA. The ligation product then hybridized to MB, resulting in a fluorescence enhancement of the MB. This assay was capable of determining protein kinase A in the range of 12.5∼150 nM, with a detection limit of 1.25 nM. Furthermore, this assay could also be used to investigate the effect of genistein on protein kinase A. It was a universal, non-radioisotopic, and homogeneous method for assaying protein kinase A.

  18. Her4 and Her2/neu tyrosine kinase domains dimerize and activate in a reconstituted in vitro system.

    Science.gov (United States)

    Monsey, John; Shen, Wei; Schlesinger, Paul; Bose, Ron

    2010-03-05

    Her4 (ErbB-4) and Her2/neu (ErbB-2) are receptor-tyrosine kinases belonging to the epidermal growth factor receptor (EGFR) family. Crystal structures of EGFR and Her4 kinase domains demonstrate kinase dimerization and activation through an allosteric mechanism. The kinase domains form an asymmetric dimer, where the C-lobe surface of one monomer contacts the N-lobe of the other monomer. EGFR kinase dimerization and activation in vitro was previously reported using a nickel-chelating lipid-liposome system, and we now apply this system to all other members of the EGFR family. Polyhistidine-tagged Her4, Her2/neu, and Her3 kinase domains are bound to these nickel-liposomes and are brought to high local concentration, mimicking what happens to full-length receptors in vivo following ligand binding. Addition of nickel-liposomes to Her4 kinase domain results in 40-fold activation in kinase activity and marked enhancement of C-terminal tail autophosphorylation. Activation of Her4 shows a sigmoidal dependence on kinase concentration, consistent with a cooperative process requiring kinase dimerization. Her2/neu kinase activity is also activated by nickel-liposomes, and is increased further by heterodimerization with Her3 or Her4. The ability of Her3 and Her4 to heterodimerize and activate other family members is studied in vitro. Her3 kinase domain readily activates Her2/neu but is a poor activator of Her4, which differs from the prediction made by the asymmetric dimer model. Mutation of Her3 residues (952)ENI(954) to the corresponding sequence in Her4 enhanced the ability of Her3 to activate Her4, demonstrating that sequence differences on the C-lobe surface influence the heterodimerization and activation of ErbB kinase domains.

  19. Non-Viral Deoxyribonucleoside Kinases

    DEFF Research Database (Denmark)

    Christiansen, Louise Slot; Munch-Petersen, Birgitte; Knecht, Wolfgang

    2015-01-01

    Deoxyribonucleoside kinases (dNKs) phosphorylate deoxyribonucleosides to their corresponding monophosphate compounds. dNks also phosphorylate deoxyribonucleoside analogues that are used in the treatment of cancer or viral infections. The study of the mammalian dNKs has therefore always been of gr...

  20. Activation of GABAB receptors inhibits protein kinase B /Glycogen Synthase Kinase 3 signaling

    Directory of Open Access Journals (Sweden)

    Lu Frances Fangjia

    2012-11-01

    Full Text Available Abstract Accumulated evidence has suggested that potentiation of cortical GABAergic inhibitory neurotransmission may be a key mechanism in the treatment of schizophrenia. However, the downstream molecular mechanisms related to GABA potentiation remain unexplored. Recent studies have suggested that dopamine D2 receptor antagonists, which are used in the clinical treatment of schizophrenia, modulate protein kinase B (Akt/glycogen synthase kinase (GSK-3 signaling. Here we report that activation of GABAB receptors significantly inhibits Akt/GSK-3 signaling in a β-arrestin-dependent pathway. Agonist stimulation of GABAB receptors enhances the phosphorylation of Akt (Thr-308 and enhances the phosphorylation of GSK-3α (Ser-21/β (Ser-9 in both HEK-293T cells expressing GABAB receptors and rat hippocampal slices. Furthermore, knocking down the expression of β-arrestin2 using siRNA abolishes the GABAB receptor-mediated modulation of GSK-3 signaling. Our data may help to identify potentially novel targets through which GABAB receptor agents may exert therapeutic effects in the treatment of schizophrenia.

  1. Glycogen synthase kinase 3β promotes liver innate immune activation by restraining AMP-activated protein kinase activation.

    Science.gov (United States)

    Zhou, Haoming; Wang, Han; Ni, Ming; Yue, Shi; Xia, Yongxiang; Busuttil, Ronald W; Kupiec-Weglinski, Jerzy W; Lu, Ling; Wang, Xuehao; Zhai, Yuan

    2018-02-13

    Glycogen synthase kinase 3β (Gsk3β [Gsk3b]) is a ubiquitously expressed kinase with distinctive functions in different types of cells. Although its roles in regulating innate immune activation and ischaemia and reperfusion injuries (IRIs) have been well documented, the underlying mechanisms remain ambiguous, in part because of the lack of cell-specific tools in vivo. We created a myeloid-specific Gsk3b knockout (KO) strain to study the function of Gsk3β in macrophages in a murine liver partial warm ischaemia model. Compared with controls, myeloid Gsk3b KO mice were protected from IRI, with diminished proinflammatory but enhanced anti-inflammatory immune responses in livers. In bone marrow-derived macrophages, Gsk3β deficiency resulted in an early reduction of Tnf gene transcription but sustained increase of Il10 gene transcription on Toll-like receptor 4 stimulation in vitro. These effects were associated with enhanced AMP-activated protein kinase (AMPK) activation, which led to an accelerated and higher level of induction of the novel innate immune negative regulator small heterodimer partner (SHP [Nr0b2]). The regulatory function of Gsk3β on AMPK activation and SHP induction was confirmed in wild-type bone marrow-derived macrophages with a Gsk3 inhibitor. Furthermore, we found that this immune regulatory mechanism was independent of Gsk3β Ser9 phosphorylation and the phosphoinositide 3-kinase-Akt signalling pathway. In vivo, myeloid Gsk3β deficiency facilitated SHP upregulation by ischaemia-reperfusion in liver macrophages. Treatment of Gsk3b KO mice with either AMPK inhibitor or SHP small interfering RNA before the onset of liver ischaemia restored liver proinflammatory immune activation and IRI in these otherwise protected hosts. Additionally, pharmacological activation of AMPK protected wild-type mice from liver IRI, with reduced proinflammatory immune activation. Inhibition of the AMPK-SHP pathway by liver ischaemia was demonstrated in tumour resection

  2. The presence of the casein kinase II phosphorylation sites of Vpu enhances the CD4+ T cell loss caused by the simian-human immunodeficiency virus SHIVKU-lbMC33 in pig-tailed macaques

    International Nuclear Information System (INIS)

    Singh, Dinesh K.; Griffin, Darcy M.; Pacyniak, Erik; Jackson, Mollie; Werle, Michael J.; Wisdom, Bo; Sun, Francis; Hout, David R.; Pinson, David M.; Gunderson, Robert S.; Powers, Michael F.; Wong, Scott W.; Stephens, Edward B.

    2003-01-01

    reversion of the glycine residues in the vpu sequences isolated from this macaque. These results contrast with those from four macaques inoculated with the parental pathogenic SHIV KU-1bMC33 , all of which developed severe CD4 + T cell loss within 1 month after inoculation. Taken together, these results indicate that casein kinase II phosphorylation sites of Vpu contributes to the pathogenicity of the SHIV KU-1bMC33 and suggest that the SHIV KU-1bMC33 /pig-tailed macaque model will be useful in analyzing amino acids/domains of Vpu that contribute to the pathogenesis of HIV-1

  3. Synthesis of ester prodrugs of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPDAP) as anti-poxvirus agents

    Czech Academy of Sciences Publication Activity Database

    Krečmerová, Marcela; Holý, Antonín; Andrei, G.; Pomeisl, Karel; Tichý, Tomáš; Břehová, Petra; Masojídková, Milena; Dračínský, Martin; Pohl, Radek; Laflamme, G.; Naesens, L.; Hui, H.; Cihlař, T.; Neyts, J.; De Clercq, E.; Balzarini, J.; Snoeck, R.

    2010-01-01

    Roč. 53, č. 19 (2010), s. 6825-6837 ISSN 0022-2623 R&D Projects: GA MŠk 1M0508; GA MŠk(CZ) ME10040 Grant - others:NIH(US) 1UC1 AI062540-01 Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphonates * prodrugs * poxvirus * herpes virus * bioterrorism Subject RIV: CC - Organic Chemistry Impact factor: 5.207, year: 2010

  4. Protein kinase CK2 in human diseases

    DEFF Research Database (Denmark)

    Guerra, Barbara; Issinger, Olaf-Georg

    2008-01-01

    Protein kinase CK2 (formerly referred to as casein kinase II) is an evolutionary conserved, ubiquitous protein kinase. There are two paralog catalytic subunits, i.e. alpha (A1) and alpha' (A2). The alpha and alpha' subunits are linked to two beta subunits to produce a heterotetrameric structure...

  5. Autoregulation of kinase dephosphorylation by ATP binding in AGC protein kinases.

    Science.gov (United States)

    Chan, Tung O; Pascal, John M; Armen, Roger S; Rodeck, Ulrich

    2012-02-01

    AGC kinases, including the three Akt (protein kinase B) isoforms, protein kinase A (PKA) and all protein kinase C (PKC) isoforms, require activation loop phosphorylation (threonine 308 in Akt1) as well as phosphorylation of a C-terminal residue (serine 473 in Akt1) for catalytic activity and phosphorylation of downstream targets. Conversely, phosphatases reverse these phosphorylations. Virtually all cellular processes are affected by AGC kinases, a circumstance that has led to intense scrutiny of the molecular mechanisms that regulate phosphorylation of these kinases. Here, we review a new layer of control of phosphorylation in Akt, PKA and PKC pointing to ATP binding pocket occupancy as a means to decelerate dephosphorylation of these and, potentially, other kinases. This additional level of kinase regulation opens the door to search for new functional motifs for the rational design of non- ATP-competitive kinase inhibitors that discriminate within and between protein kinase families.

  6. Autoregulation of kinase dephosphorylation by ATP binding to AGC protein kinases

    Science.gov (United States)

    Pascal, John M; Armen, Roger S

    2012-01-01

    AGC kinases, including the three Akt (protein kinase B) isoforms, protein kinase A (PKA) and all protein kinase C (PKC) isoforms, require activation loop phosphorylation (threonine 308 in Akt1) as well as phosphorylation of a C-terminal residue (serine 473 in Akt1) for catalytic activity and phosphorylation of downstream targets. Conversely, phosphatases reverse these phosphorylations. Virtually all cellular processes are affected by AGC kinases, a circumstance that has led to intense scrutiny of the molecular mechanisms that regulate phosphorylation of these kinases. Here, we review a new layer of control of phosphorylation in Akt, PKA and PKC pointing to ATP binding pocket occupancy as a means to decelerate dephosphorylation of these and, potentially, other kinases. This additional level of kinase regulation opens the door to search for new functional motifs for the rational design of non-ATP-competitive kinase inhibitors that discriminate within and between protein kinase families. PMID:22262182

  7. Synthesis and evaluation of mutual azo prodrug of 5-aminosalicylic acid linked to 2-phenylbenzoxazole-2-yl-5-acetic acid in ulcerative colitis

    Directory of Open Access Journals (Sweden)

    Jilani JA

    2013-07-01

    Full Text Available Jamal A Jilani,1 Maha Shomaf,2 Karem H Alzoubi3 1Department of Medicinal Chemistry and Pharmacognosy, Jordan University of Science and Technology, Irbid, Jordan; 2Department of Pathology, Jordan University, Amman, Jordan; 3Department of Clinical Pharmacy, Jordan University of Science and Technology, Irbid, Jordan Abstract: In this study, the syntheses of 4-aminophenylbenzoxazol-2-yl-5-acetic acid, (an analogue of a known nonsteroidal anti-inflammatory drug [NSAID] and 5-[4-(benzoxazol-2-yl-5-acetic acidphenylazo]-2-hydroxybenzoic acid (a novel mutual azo prodrug of 5-aminosalicylic acid [5-ASA] are reported. The structures of the synthesized compounds were confirmed using infrared (IR, hydrogen-1 nuclear magnetic resonance (1H NMR, and mass spectrometry (MS spectroscopy. Incubation of the azo compound with rat cecal contents demonstrated the susceptibility of the prepared azo prodrug to bacterial azoreductase enzyme. The azo compound and the 4-aminophenylbenzoxazol-2-yl-5-acetic acid were evaluated for inflammatory bowel diseases, in trinitrobenzenesulfonic acid (TNB-induced colitis in rats. The synthesized diazo compound and the 4-aminophenylbenzoxazol-2-yl-5-acetic acid were found to be as effective as 5-aminosalicylic acid for ulcerative colitis. The results of this work suggest that the 4-aminophenylbenzoxazol-2-yl-5-acetic acid may represent a new lead for treatment of ulcerative colitis. Keywords: benzoxazole acetic acid, azo prodrug, colon drug delivery

  8. Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Reinhard Klein

    2008-01-01

    Full Text Available Gene directed-enzyme prodrug therapy (GDEPT is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1 metabolizes the prodrugs cyclophosphamide (CPA and ifosfamide (IFA to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respective IC50 values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

  9. Acetal-Linked Paclitaxel Polymeric Prodrug Based on Functionalized mPEG-PCL Diblock Polymer for pH-Triggered Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yinglei Zhai

    2017-12-01

    Full Text Available The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX prodrug micelles based on functionalized poly(ethylene glycol-poly(ε-caprolactone (mPEG-PCL diblock polymer with an acid-cleavable acetal (Ace linkage (mPEG-PCL-Ace-PTX. The mPEG-PCL-Ace-PTX5 with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX5 micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX5 micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy.

  10. Src kinase regulation by phosphorylation and dephosphorylation

    International Nuclear Information System (INIS)

    Roskoski, Robert

    2005-01-01

    Src and Src-family protein-tyrosine kinases are regulatory proteins that play key roles in cell differentiation, motility, proliferation, and survival. The initially described phosphorylation sites of Src include an activating phosphotyrosine 416 that results from autophosphorylation, and an inhibiting phosphotyrosine 527 that results from phosphorylation by C-terminal Src kinase (Csk) and Csk homologous kinase. Dephosphorylation of phosphotyrosine 527 increases Src kinase activity. Candidate phosphotyrosine 527 phosphatases include cytoplasmic PTP1B, Shp1 and Shp2, and transmembrane enzymes include CD45, PTPα, PTPε, and PTPλ. Dephosphorylation of phosphotyrosine 416 decreases Src kinase activity. Thus far PTP-BL, the mouse homologue of human PTP-BAS, has been shown to dephosphorylate phosphotyrosine 416 in a regulatory fashion. The platelet-derived growth factor receptor protein-tyrosine kinase mediates the phosphorylation of Src Tyr138; this phosphorylation has no direct effect on Src kinase activity. The platelet-derived growth factor receptor and the ErbB2/HER2 growth factor receptor protein-tyrosine kinases mediate the phosphorylation of Src Tyr213 and activation of Src kinase activity. Src kinase is also a substrate for protein-serine/threonine kinases including protein kinase C (Ser12), protein kinase A (Ser17), and CDK1/cdc2 (Thr34, Thr46, and Ser72). Of the three protein-serine/threonine kinases, only phosphorylation by CDK1/cdc2 has been demonstrated to increase Src kinase activity. Although considerable information on the phosphoprotein phosphatases that catalyze the hydrolysis of Src phosphotyrosine 527 is at hand, the nature of the phosphatases that mediate the hydrolysis of phosphotyrosine 138 and 213, and phosphoserine and phosphothreonine residues has not been determined

  11. Canine osteosarcoma cells exhibit resistance to aurora kinase inhibitors.

    Science.gov (United States)

    Cannon, C M; Pozniak, J; Scott, M C; Ito, D; Gorden, B H; Graef, A J; Modiano, J F

    2015-03-01

    We evaluated the effect of Aurora kinase inhibitors AZD1152 and VX680 on canine osteosarcoma cells. Cytotoxicity was seen in all four cell lines; however, half-maximal inhibitory concentrations were significantly higher than in human leukaemia and canine lymphoma cells. AZD1152 reduced Aurora kinase B phosphorylation, indicating resistance was not because of failure of target recognition. Efflux mediated by ABCB1 and ABCG2 transporters is one known mechanism of resistance against these drugs and verapamil enhanced AZD1152-induced apoptosis; however, these transporters were only expressed by a small percentage of cells in each line and the effects of verapamil were modest, suggesting other mechanisms contribute to resistance. Our results indicate that canine osteosarcoma cells are resistant to Aurora kinase inhibitors and suggest that these compounds are unlikely to be useful as single agents for this disease. Further investigation of these resistance mechanisms and the potential utility of Aurora kinase inhibitors in multi-agent protocols is warranted. © 2013 Blackwell Publishing Ltd.

  12. HIV-1 Nef interaction influences the ATP-binding site of the Src-family kinase, Hck

    Directory of Open Access Journals (Sweden)

    Pene-Dumitrescu Teodora

    2012-03-01

    Full Text Available Abstract Background Nef is an HIV-1 accessory protein essential for viral replication and AIDS progression. Nef interacts with a multitude of host cell signaling partners, including members of the Src kinase family. Nef preferentially activates Hck, a Src-family kinase (SFK strongly expressed in macrophages and other HIV target cells, by binding to its regulatory SH3 domain. Recently, we identified a series of kinase inhibitors that preferentially inhibit Hck in the presence of Nef. These compounds also block Nef-dependent HIV replication, validating the Nef-SFK signaling pathway as an antiretroviral drug target. Our findings also suggested that by binding to the Hck SH3 domain, Nef indirectly affects the conformation of the kinase active site to favor inhibitor association. Results To test this hypothesis, we engineered a "gatekeeper" mutant of Hck with enhanced sensitivity to the pyrazolopyrimidine tyrosine kinase inhibitor, NaPP1. We also modified the RT loop of the Hck SH3 domain to enhance interaction of the kinase with Nef. This modification stabilized Nef:Hck interaction in solution-based kinase assays, as a way to mimic the more stable association that likely occurs at cellular membranes. Introduction of the modified RT loop rendered Hck remarkably more sensitive to activation by Nef, and led to a significant decrease in the Km for ATP as well as enhanced inhibitor potency. Conclusions These observations suggest that stable interaction with Nef may induce Src-family kinase active site conformations amenable to selective inhibitor targeting.

  13. Signaling network of the Btk family kinases.

    Science.gov (United States)

    Qiu, Y; Kung, H J

    2000-11-20

    The Btk family kinases represent new members of non-receptor tyrosine kinases, which include Btk/Atk, Itk/Emt/Tsk, Bmx/Etk, and Tec. They are characterized by having four structural modules: PH (pleckstrin homology) domain, SH3 (Src homology 3) domain, SH2 (Src homology 2) domain and kinase (Src homology 1) domain. Increasing evidence suggests that, like Src-family kinases, Btk family kinases play central but diverse modulatory roles in various cellular processes. They participate in signal transduction in response to virtually all types of extracellular stimuli which are transmitted by growth factor receptors, cytokine receptors, G-protein coupled receptors, antigen-receptors and integrins. They are regulated by many non-receptor tyrosine kinases such as Src, Jak, Syk and FAK family kinases. In turn, they regulate many of major signaling pathways including those of PI3K, PLCgamma and PKC. Both genetic and biochemical approaches have been used to dissect the signaling pathways and elucidate their roles in growth, differentiation and apoptosis. An emerging new role of this family of kinases is cytoskeletal reorganization and cell motility. The physiological importance of these kinases was amply demonstrated by their link to the development of immunodeficiency diseases, due to germ-line mutations. The present article attempts to review the structure and functions of Btk family kinases by summarizing our current knowledge on the interacting partners associated with the different modules of the kinases and the diverse signaling pathways in which they are involved.

  14. Receptor-interacting protein (RIP) kinase family

    Science.gov (United States)

    Zhang, Duanwu; Lin, Juan; Han, Jiahuai

    2010-01-01

    Receptor-interacting protein (RIP) kinases are a group of threonine/serine protein kinases with a relatively conserved kinase domain but distinct non-kinase regions. A number of different domain structures, such as death and caspase activation and recruitment domain (CARD) domains, were found in different RIP family members, and these domains should be keys in determining the specific function of each RIP kinase. It is known that RIP kinases participate in different biological processes, including those in innate immunity, but their downstream substrates are largely unknown. This review will give an overview of the structures and functions of RIP family members, and an update of recent progress in RIP kinase research. PMID:20383176

  15. αvβ3 integrin-targeted micellar mertansine prodrug effectively inhibits triple-negative breast cancer in vivo

    Directory of Open Access Journals (Sweden)

    Zhong P

    2017-10-01

    Full Text Available Ping Zhong,1,2 Xiaolei Gu,1,2 Ru Cheng,1,2 Chao Deng,1,2 Fenghua Meng,1,2 Zhiyuan Zhong1,2 1Biomedical Polymers Laboratory, 2Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China Abstract: Antibody-mertansine (DM1 conjugates (AMCs are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs. Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP can effectively target and deliver DM1 to αvβ3 integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC50 of 0.18 µM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control. The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at

  16. Oncoprotein protein kinase antibody kit

    Science.gov (United States)

    Karin, Michael [San Diego, CA; Hibi, Masahiko [San Diego, CA; Lin, Anning [La Jolla, CA

    2008-12-23

    An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

  17. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  18. Fluorescence Polarization Screening Assays for Small Molecule Allosteric Modulators of ABL Kinase Function.

    Science.gov (United States)

    Grover, Prerna; Shi, Haibin; Baumgartner, Matthew; Camacho, Carlos J; Smithgall, Thomas E

    2015-01-01

    The ABL protein-tyrosine kinase regulates intracellular signaling pathways controlling diverse cellular processes and contributes to several forms of cancer. The kinase activity of ABL is repressed by intramolecular interactions involving its regulatory Ncap, SH3 and SH2 domains. Small molecules that allosterically regulate ABL kinase activity through its non-catalytic domains may represent selective probes of ABL function. Here we report a screening assay for chemical modulators of ABL kinase activity that target the regulatory interaction of the SH3 domain with the SH2-kinase linker. This fluorescence polarization (FP) assay is based on a purified recombinant ABL protein consisting of the N-cap, SH3 and SH2 domains plus the SH2-kinase linker (N32L protein) and a short fluorescein-labeled probe peptide that binds to the SH3 domain. In assay development experiments, we found that the probe peptide binds to the recombinant ABL N32L protein in vitro, producing a robust FP signal that can be competed with an excess of unlabeled peptide. The FP signal is not observed with control N32L proteins bearing either an inactivating mutation in the SH3 domain or enhanced SH3:linker interaction. A pilot screen of 1200 FDA-approved drugs identified four compounds that specifically reduced the FP signal by at least three standard deviations from the untreated controls. Secondary assays showed that one of these hit compounds, the antithrombotic drug dipyridamole, enhances ABL kinase activity in vitro to a greater extent than the previously described ABL agonist, DPH. Docking studies predicted that this compound binds to a pocket formed at the interface of the SH3 domain and the linker, suggesting that it activates ABL by disrupting this regulatory interaction. These results show that screening assays based on the non-catalytic domains of ABL can identify allosteric small molecule regulators of kinase function, providing a new approach to selective drug discovery for this important

  19. A double-mutant collection targeting MAP kinase related genes in Arabidopsis for studying genetic interactions.

    Science.gov (United States)

    Su, Shih-Heng; Krysan, Patrick J

    2016-12-01

    Mitogen-activated protein kinase cascades are conserved in all eukaryotes. In Arabidopsis thaliana there are approximately 80 genes encoding MAP kinase kinase kinases (MAP3K), 10 genes encoding MAP kinase kinases (MAP2K), and 20 genes encoding MAP kinases (MAPK). Reverse genetic analysis has failed to reveal abnormal phenotypes for a majority of these genes. One strategy for uncovering gene function when single-mutant lines do not produce an informative phenotype is to perform a systematic genetic interaction screen whereby double-mutants are created from a large library of single-mutant lines. Here we describe a new collection of 275 double-mutant lines derived from a library of single-mutants targeting genes related to MAP kinase signaling. To facilitate this study, we developed a high-throughput double-mutant generating pipeline using a system for growing Arabidopsis seedlings in 96-well plates. A quantitative root growth assay was used to screen for evidence of genetic interactions in this double-mutant collection. Our screen revealed four genetic interactions, all of which caused synthetic enhancement of the root growth defects observed in a MAP kinase 4 (MPK4) single-mutant line. Seeds for this double-mutant collection are publicly available through the Arabidopsis Biological Resource Center. Scientists interested in diverse biological processes can now screen this double-mutant collection under a wide range of growth conditions in order to search for additional genetic interactions that may provide new insights into MAP kinase signaling. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.