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Sample records for growth inhibition caused

  1. Bacterial Ammonia Causes Significant Plant Growth Inhibition

    PubMed Central

    Weise, Teresa; Kai, Marco; Piechulla, Birgit

    2013-01-01

    Many and complex plant-bacteria inter-relationships are found in the rhizosphere, since plants release a variety of photosynthetic exudates from their roots and rhizobacteria produce multifaceted specialized compounds including rich mixtures of volatiles, e.g., the bouquet of Serratia odorifera 4Rx13 is composed of up to 100 volatile organic and inorganic compounds. Here we show that when growing on peptone-rich nutrient medium S. odorifera 4Rx13 and six other rhizobacteria emit high levels of ammonia, which during co-cultivation in compartmented Petri dishes caused alkalization of the neighboring plant medium and subsequently reduced the growth of A. thaliana. It is argued that in nature high-protein resource degradations (carcasses, whey, manure and compost) are also accompanied by bacterial ammonia emission which alters the pH of the rhizosphere and thereby influences organismal diversity and plant-microbe interactions. Consequently, bacterial ammonia emission may be more relevant for plant colonization and growth development than previously thought. PMID:23691060

  2. Decreased growth-induced water potential: A primary cause of growth inhibition at low water potentials

    SciTech Connect

    Nonami, Hiroshi; Wu, Yajun; Boyer, J.S.

    1997-06-01

    Cell enlargement depends on a growth-induced difference in water potential to move water into the cells. Water deficits decrease this potential difference and inhibit growth. To investigate whether the decrease causes the growth inhibition, pressure was applied to the roots of soybean seedlings and the growth and potential difference were monitored in the stems. In water-limited plants, the inhibited stem growth increased when the roots were pressurized and it reverted to the previous rate when the pressure was released. The pressure around the roots was perceived as an increased turgor in the stem in small cells next to the xylem, but not in outlying cortical cells. This local effect implied that water transport was impeded by the small cells. The diffusivity for water was much less in the small cells than in the outlying cells. The small cells thus were a barrier that caused the growth-induced potential difference to be large during rapid growth, but to reverse locally during the early part of a water deficit. Such a barrier may be a frequent property of meristems. Because stem growth responded to the pressure-induced recovery of the potential difference across this barrier, we conclude that a decrease in the growth-induced potential difference was a primary cause of the inhibition.

  3. Direct inhibition of Retinoblastoma phosphorylation by Nimbolide causes cell cycle arrest and suppresses glioblastoma growth

    PubMed Central

    Anderson, Jane; Liu, Xiaona; Henry, Heather; Gasilina, Anjelika; Nassar, Nicholas; Ghosh, Jayeeta; Clark, Jason P; Kumar, Ashish; Pauletti, Giovanni M.; Ghosh, Pradip K; Dasgupta, Biplab

    2013-01-01

    Purpose Classical pharmacology allows the use and development of conventional phytomedicine faster and more economically than conventional drugs. This approach should be tested for their efficacy in terms of complementarity and disease control. The purpose of this study was to determine the molecular mechanisms by which nimbolide, a triterpenoid found in the well-known medicinal plant Azadirachta indica controls glioblastoma (GBM) growth. Experimental Design Using in vitro signaling, anchorage-independent growth, kinase assays, and xenograft models, we investigated the mechanisms of its growth inhibition in glioblastoma. Results We show that nimbolide or an ethanol soluble fraction of A. indica leaves (Azt) that contains nimbolide as the principal cytotoxic agent is highly cytotoxic against GBM in vitro and in vivo. Azt caused cell cycle arrest, most prominently at the G1-S stage in GBM cells expressing EGFRvIII, an oncogene present in about 20-25% of GBMs. Azt/nimbolide directly inhibited CDK4/CDK6 kinase activity leading to hypophosphorylation of the retinoblastoma (RB) protein, cell cycle arrest at G1-S and cell death. Independent of RB hypophosphorylation, Azt also significantly reduced proliferative and survival advantage of GBM cells in vitro and in tumor xenografts by downregulating Bcl2 and blocking growth factor induced phosphorylation of Akt, Erk1/2 and STAT3. These effects were specific since Azt did not affect mTOR or other cell cycle regulators. In vivo, Azt completely prevented initiation and inhibited progression of GBM growth. Conclusions Our preclinical findings demonstrate Nimbolide as a potent anti-glioma agent that blocks cell cycle and inhibits glioma growth in vitro and in vivo. PMID:24170547

  4. Gefitinib causes growth arrest and inhibition of metastasis in human chondrosarcoma cells.

    PubMed

    Song, Jian; Zhu, Jiaxue; Zhao, Qiang; Tian, Baofang

    2015-01-01

    Chondrosarcomas are primary malignant cartilage-forming tumors of bone which are not responsive either to chemotherapy or radiation treatment and display potent capacity to invade locally and cause distant metastasis. Epidermal growth factor receptor (EGFR) pathway plays an important role in the development and progression of many cancers. However, the effect of EGFR inhibitor gefitinib on cell growth and metastasis in human chondrosarcoma cells is largely unknown. Features of the protein expression of EGFR in 3 human chondrosarcoma cell lines JJ2012, SW1353 and OUMS27 were analyzed. The inhibitory effects of EGFR inhibitor gefitinib on cell proliferation, cell cycle and metastasis were assessed by using MTS, flow cytometry and migration assays, respectively. The expression of metastasis-related proteins was evaluated by western blotting. All the three human chondrosarcoma cell lines expressed EGFR protein. Gefitinib significantly inhibited the growth, induced cell cycle arrest and decreased the migra- tion ability of human chondrosarcoma cells. In addition, gefitinib also reduced the expression of metastasis-related proteins, basic fibroblast growth factor (bFGF), matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9). The discovery that gefitinib inhibited the proliferation and reduced the metastatic capacity of chondrosarcoma cells may help increase the understanding of the mechanism underlying human chondrosarcoma growth and metastasis. Thus, gefitinib may represent a promising agent for controlling chondrosarcoma proliferation and metastasis.

  5. Polydatin inhibits growth of lung cancer cells by inducing apoptosis and causing cell cycle arrest.

    PubMed

    Zhang, Yusong; Zhuang, Zhixiang; Meng, Qinghui; Jiao, Yang; Xu, Jiaying; Fan, Saijun

    2014-01-01

    Polydatin (PD), a small natural compound from Polygonum cuspidatum, has a number of biological functions. However, the anticancer activity of PD has been poorly investigated. In the present study, thiazolyl blue tetrazolium bromide assay was used to evaluate the inhibitory effect of PD on cell growth. Cell cycle distribution and apoptosis were investigated by flow cytometry. In addition, the expression of several proteins associated with apoptosis and cell cycle were analyzed by western blot analysis. The results demonstrated that PD significantly inhibits the proliferation of A549 and NCI-H1975 lung cancer cell lines and causes dose-dependent apoptosis. Cell cycle analysis revealed that PD induces S phase cell cycle arrest. Western blot analysis showed that the expression of Bcl-2 decreased as that of Bax increased, and the expression of cyclin D1 was also suppressed. The results suggest that PD has potential therapeutic applications in the treatment of lung cancer.

  6. Polydatin inhibits growth of lung cancer cells by inducing apoptosis and causing cell cycle arrest

    PubMed Central

    ZHANG, YUSONG; ZHUANG, ZHIXIANG; MENG, QINGHUI; JIAO, YANG; XU, JIAYING; FAN, SAIJUN

    2014-01-01

    Polydatin (PD), a small natural compound from Polygonum cuspidatum, has a number of biological functions. However, the anticancer activity of PD has been poorly investigated. In the present study, thiazolyl blue tetrazolium bromide assay was used to evaluate the inhibitory effect of PD on cell growth. Cell cycle distribution and apoptosis were investigated by flow cytometry. In addition, the expression of several proteins associated with apoptosis and cell cycle were analyzed by western blot analysis. The results demonstrated that PD significantly inhibits the proliferation of A549 and NCI-H1975 lung cancer cell lines and causes dose-dependent apoptosis. Cell cycle analysis revealed that PD induces S phase cell cycle arrest. Western blot analysis showed that the expression of Bcl-2 decreased as that of Bax increased, and the expression of cyclin D1 was also suppressed. The results suggest that PD has potential therapeutic applications in the treatment of lung cancer. PMID:24348867

  7. Allelochemical stress causes inhibition of growth and oxidative damage in Lycopersicon esculentum Mill.

    PubMed

    Lara-Nuñez, Aurora; Romero-Romero, Teresa; Ventura, José Luis; Blancas, Vania; Anaya, Ana Luisa; Cruz-Ortega, Rocio

    2006-11-01

    The aim of this study was to analyse the effect of allelochemical stress on Lycopersicon esculentum growth. Our results showed that allelochemical stress caused by Sicyos deppei aqueous leachate inhibited root growth but not germination, and produced an imbalance in the oxidative status of cells in both ungerminated seeds and in primary roots. We observed changes in activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR) and the plasma membrane NADPH oxidase, as well as in the levels of H(2)O(2) and O(2) (*-) in seeds at 12 and 24 h, and in primary roots at 48 and 72 h of treatment, which could account for the oxidative imbalance. There were changes in levels of expression of the mentioned enzymes, but without a correlation with their respective activities. Higher levels of membrane lipid peroxidation were observed in primary roots at 48 and 72 h of treatment. No effect on the expression of metacaspase and the PR1 was observed as indicators of cell death or induction of plant defence. This paper contributes to the understanding of plant-plant interactions through the phytotoxic allelochemicals released in an aqueous leachate of the weed S. deppei, which cause a negative effect on other plants.

  8. Neutral sphingomyelinase (SMPD3) deficiency disrupts the Golgi secretory pathway and causes growth inhibition

    PubMed Central

    Stoffel, Wilhelm; Hammels, Ina; Jenke, Bitta; Binczek, Erika; Schmidt-Soltau, Inga; Brodesser, Susanne; Schauss, Astrid; Etich, Julia; Heilig, Juliane; Zaucke, Frank

    2016-01-01

    Systemic loss of neutral sphingomyelinase (SMPD3) in mice leads to a novel form of systemic, juvenile hypoplasia (dwarfism). SMPD3 deficiency in mainly two growth regulating cell types contributes to the phenotype, in chondrocytes of skeletal growth zones to skeletal malformation and chondrodysplasia, and in hypothalamic neurosecretory neurons to systemic hypothalamus–pituitary–somatotropic hypoplasia. The unbiased smpd3−/− mouse mutant and derived smpd3−/− primary chondrocytes were instrumental in defining the enigmatic role underlying the systemic and cell autonomous role of SMPD3 in the Golgi compartment. Here we describe the unprecedented role of SMPD3. SMPD3 deficiency disrupts homeostasis of sphingomyelin (SM), ceramide (Cer) and diacylglycerol (DAG) in the Golgi SMPD3-SMS1 (SM-synthase1) cycle. Cer and DAG, two fusogenic intermediates, modify the membrane lipid bilayer for the initiation of vesicle formation and transport. Dysproteostasis, unfolded protein response, endoplasmic reticulum stress and apoptosis perturb the Golgi secretory pathway in the smpd3−/− mouse. Secretion of extracellular matrix proteins is arrested in chondrocytes and causes skeletal malformation and chondrodysplasia. Similarly, retarded secretion of proteo-hormones in hypothalamic neurosecretory neurons leads to hypothalamus induced combined pituitary hormone deficiency. SMPD3 in the regulation of the protein vesicular secretory pathway may become a diagnostic target in the etiology of unknown forms of juvenile growth and developmental inhibition. PMID:27882938

  9. Prevention of 5-Fluorouracil-Caused Growth Inhibition in Sordaria fimicola

    PubMed Central

    Schoen, Howard F.; Berech, John

    1977-01-01

    Growth (dry weight accumulation) of Sordaria fimicola in standing liquid culture (sucrose-nitrate-salts-vitamins) is inhibited by the presence of 5 μM 5-fluorouracil in the medium. This inhibition is completely prevented by uracil, deoxyuridine, and 5-bromouracil, partly prevented (40 to 90% of growth observed without 5-fluorouracil) by uridine, thymidine, and 5-bromodeoxyuridine, and slightly prevented by trifluorothymine, cytosine, cytidine, deoxycytidine, and 5-methylcytosine (all at 0.5 to 1 mM). Thymidine and thymine riboside were without any apparent effect. Growth is also inhibited by 0.2 mM 6-azauracil, and this inhibition was completely prevented by uracil and uridine, partly prevented by deoxyuridine, 5-bromouracil, cytidine, and 5-methylcytosine, and slightly prevented by thymine, thymidine, 5-bromodeoxyuridine, cytosine, and deoxycytidine. The data suggest that the observed inhibition of growth by 5-fluorouracil is due to inhibition of both ribonucleic acid and deoxyribonucleic acid synthesis. The data also allow inferences concerning pyrimidine interconversions in S. fimicola; i.e., thymine can be anabolized to thymidylic acid without first being demethylated, although demethylation appears to occur also. PMID:848926

  10. Prevention of 5-fluorouracil-caused growth inhibition in Sordaria fimicola.

    PubMed

    Schoen, H F; Berech, J

    1977-02-01

    Growth (dry weight accumulation) of Sordaria fimicola in standing liquid culture (sucrose-nitrate-salts-vitamins) is inhibited by the presence of 5 muM 5-fluorouracil in the medium. This inhibition is completely prevented by uracil, deoxyuridine, and 5-bromouracil, partly prevented (40 to 90% of growth observed without 5-fluorouracil) by uridine, thymidine, and 5-bromodeoxyuridine, and slightly prevented by trifluorothymine, cytosine, cytidine, deoxycytidine, and 5-methylcytosine (all at 0.5 to 1 mM). Thymidine and thymine riboside were without any apparent effect. Growth is also inhibited by 0.2 mM 6-azauracil, and this inhibition was completely prevented by uracil and uridine, partly prevented by deoxyuridine, 5-bromouracil, cytidine, and 5-methylcytosine, and slightly prevented by thymine, thymidine, 5-bromodeoxyuridine, cytosine, and deoxycytidine. The data suggest that the observed inhibition of growth by 5-fluorouracil is due to inhibition of both ribonucleic acid and deoxyribonucleic acid synthesis. The data also allow inferences concerning pyrimidine interconversions in S. fimicola; i.e., thymine can be anabolized to thymidylic acid without first being demethylated, although demethylation appears to occur also.

  11. Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings 1

    PubMed Central

    Creelman, Robert A.; Mason, Hugh S.; Bensen, Robert J.; Boyer, John S.; Mullet, John E.

    1990-01-01

    Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite. Images Figure 6 Figure 7 PMID:16667248

  12. Parafibromin inhibits cancer cell growth and causes G1 phase arrest

    SciTech Connect

    Zhang Chun; Kong Dong; Tan, M.-H.; Pappas, Donald L.; Wang, P.-F.; Chen, Jindong; Farber, Leslie; Zhang Nian; Koo, H.-M.; Weinreich, Michael; Williams, Bart O.; Teh, B.T. . E-mail: bin.teh@vai.org

    2006-11-10

    The HRPT2 (hereditary hyperparathyroidism type 2) tumor suppressor gene encodes a ubiquitously expressed 531 amino acid protein termed parafibromin. Inactivation of parafibromin predisposes one to the development of HPT-JT syndrome. To date, the role of parafibromin in tumorigenesis is largely unknown. Here, we report that parafibromin is a nuclear protein that possesses anti-proliferative properties. We show that overexpression of parafibromin inhibits colony formation and cellular proliferation, and induces cell cycle arrest in the G1 phase. Moreover, HPT-JT syndrome-derived mutations in HRPT2 behave in a dominant-negative manner by abolishing the ability of parafibromin to suppress cell proliferation. These findings suggest that parafibromin has a critical role in cell growth, and mutations in HRPT2 can directly inhibit this role.

  13. Enhanced Lignin Monomer Production Caused by Cinnamic Acid and Its Hydroxylated Derivatives Inhibits Soybean Root Growth

    PubMed Central

    Lima, Rogério Barbosa; Salvador, Victor Hugo; dos Santos, Wanderley Dantas; Bubna, Gisele Adriana; Finger-Teixeira, Aline; Soares, Anderson Ricardo; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids) are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway) in a growth chamber for 24 h. In general, the results showed that 1) cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2) cinnamic and p-coumaric acids increased p-hydroxyphenyl (H) monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G) content, and sinapic acid increased sinapyl (S) content; 3) when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H), cinnamic acid reduced H, G and S contents; and 4) when applied in conjunction with 3,4-(methylenedioxy)cinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL), p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth. PMID:24312480

  14. Enhanced lignin monomer production caused by cinnamic Acid and its hydroxylated derivatives inhibits soybean root growth.

    PubMed

    Lima, Rogério Barbosa; Salvador, Victor Hugo; dos Santos, Wanderley Dantas; Bubna, Gisele Adriana; Finger-Teixeira, Aline; Soares, Anderson Ricardo; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids) are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway) in a growth chamber for 24 h. In general, the results showed that 1) cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2) cinnamic and p-coumaric acids increased p-hydroxyphenyl (H) monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G) content, and sinapic acid increased sinapyl (S) content; 3) when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H), cinnamic acid reduced H, G and S contents; and 4) when applied in conjunction with 3,4-(methylenedioxy)cinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL), p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth.

  15. Simulated coal spill causes mortality and growth inhibition in tropical marine organisms

    NASA Astrophysics Data System (ADS)

    Berry, Kathryn L. E.; Hoogenboom, Mia O.; Flores, Florita; Negri, Andrew P.

    2016-05-01

    Coal is a principal fossil fuel driving economic and social development, and increases in global coal shipments have paralleled expansion of the industry. To identify the potential harm associated with chronic marine coal contamination, three taxa abundant in tropical marine ecosystems (the coral Acropora tenuis, the reef fish Acanthochromis polyacanthus and the seagrass Halodule uninervis) were exposed to five concentrations (0–275 mg coal l‑1) of suspended coal dust (<63 μm) over 28 d. Results demonstrate that chronic coal exposure can cause considerable lethal effects on corals, and reductions in seagrass and fish growth rates. Coral survivorship and seagrass growth rates were inversely related to increasing coal concentrations (≥38 mg coal l‑1) and effects increased between 14 and 28 d, whereas fish growth rates were similarly depressed at all coal concentrations tested. This investigation provides novel insights into direct coal impacts on key tropical taxa for application in the assessment of risks posed by increasing coal shipments in globally threatened marine ecosystems.

  16. Simulated coal spill causes mortality and growth inhibition in tropical marine organisms

    PubMed Central

    Berry, Kathryn L. E.; Hoogenboom, Mia O.; Flores, Florita; Negri, Andrew P.

    2016-01-01

    Coal is a principal fossil fuel driving economic and social development, and increases in global coal shipments have paralleled expansion of the industry. To identify the potential harm associated with chronic marine coal contamination, three taxa abundant in tropical marine ecosystems (the coral Acropora tenuis, the reef fish Acanthochromis polyacanthus and the seagrass Halodule uninervis) were exposed to five concentrations (0–275 mg coal l−1) of suspended coal dust (<63 μm) over 28 d. Results demonstrate that chronic coal exposure can cause considerable lethal effects on corals, and reductions in seagrass and fish growth rates. Coral survivorship and seagrass growth rates were inversely related to increasing coal concentrations (≥38 mg coal l−1) and effects increased between 14 and 28 d, whereas fish growth rates were similarly depressed at all coal concentrations tested. This investigation provides novel insights into direct coal impacts on key tropical taxa for application in the assessment of risks posed by increasing coal shipments in globally threatened marine ecosystems. PMID:27174014

  17. Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings : Analysis of Growth, Sugar Accumulation, and Gene Expression.

    PubMed

    Creelman, R A; Mason, H S; Bensen, R J; Boyer, J S; Mullet, J E

    1990-01-01

    Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite.

  18. In vitro growth inhibition of mastitis causing bacteria by phenolics and metal chelators

    SciTech Connect

    Chew, B.P.; Tjoelker, L.W.; Tanaka, T.S.

    1985-11-01

    Antimicrobial activities of three phenolic compounds and four metal chelators were tested at 0, 250, 500, and 1000 ppm in vitro against four major mastitis-causing bacteria, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pnuemoniae, and Escherichia coli. Overall, butylated hydroxyanisole and tert-butylhydroquinone showed the greatest antimicrobial activity. These phenolics were bactericidal at 250 to 500 ppm against all four bacteria tested. The butylated hydroxytoluene was bactericidal against the gram-positive bacteria but was ineffective against the coliforms. At 250 ppm, disodium ethylenediaminetetraacetic acid was bactericidal against the gram-positive bacteria but much less effective against the gram-negatives. However, diethylene-triaminepentaacetic acid was more growth inhibitory than ethylenediaminetetraacetic acid against the gram-negative bacteria and especially against Escherichia coli. All other compounds were generally much less effective or ineffective against all four microorganisms. Therefore, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid may have practical implications in the prevention or treatment of bovine mastitis.

  19. Inhibition of root growth by narciclasine is caused by DNA damage-induced cell cycle arrest in lettuce seedlings.

    PubMed

    Hu, Yanfeng; Li, Jiaolong; Yang, Lijing; Nan, Wenbin; Cao, Xiaoping; Bi, Yurong

    2014-09-01

    Narciclasine (NCS) is an Amaryllidaceae alkaloid isolated from Narcissus tazetta bulbs. Its phytotoxic effects on plant growth were examined in lettuce (Lactuca sativa L.) seedlings. Results showed that high concentrations (0.5-5 μM) of NCS restricted the growth of lettuce roots in a dose-dependent manner. In NCS-treated lettuce seedlings, the following changes were detected: reduction of mitotic cells and cell elongation in the mature region, inhibition of proliferation of meristematic cells, and cell cycle. Moreover, comet assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay indicated that higher levels NCS (0.5-5 μM) induced DNA damage in root cells of lettuce. The decrease in meristematic cells and increase in DNA damage signals in lettuce roots in responses to NCS are in a dose-dependent manner. NCS-induced reactive oxygen species accumulation may explain an increase in DNA damage in lettuce roots. Thus, the restraint of root growth is due to cell cycle arrest which is caused by NCS-induced DNA damage. In addition, it was also found that NCS (0.5-5 μM) inhibited the root hair development of lettuce seedlings. Further investigations on the underlying mechanism revealed that both auxin and ethylene signaling pathways are involved in the response of root hairs to NCS.

  20. Hexavalent chromium reduction in Desulfovibrio vulgaris Hildenborough causes transitory inhibition of sulfate reduction and cell growth.

    PubMed

    Klonowska, A; Clark, M E; Thieman, S B; Giles, B J; Wall, J D; Fields, M W

    2008-04-01

    Desulfovibrio vulgaris Hildenborough is a well-studied sulfate reducer that can reduce heavy metals and radionuclides [e.g., Cr(VI) and U(VI)]. Cultures grown in a defined medium had a lag period of approximately 30 h when exposed to 0.05 mM Cr(VI). Substrate analyses revealed that although Cr(VI) was reduced within the first 5 h, growth was not observed for an additional 20 h. The growth lag could be explained by a decline in cell viability; however, during this time small amounts of lactate were still utilized without sulfate reduction or acetate formation. Approximately 40 h after Cr exposure (0.05 mM), sulfate reduction occurred concurrently with the accumulation of acetate. Similar amounts of hydrogen were produced by Cr-exposed cells compared to control cells, and lactate was not converted to glycogen during non-growth conditions. D. vulgaris cells treated with a reducing agent and then exposed to Cr(VI) still experienced a growth lag, but the addition of ascorbate at the time of Cr(VI) addition prevented the lag period. In addition, cells grown on pyruvate displayed more tolerance to Cr(VI) compared to lactate-grown cells. These results indicated that D. vulgaris utilized lactate during Cr(VI) exposure without the reduction of sulfate or production of acetate, and that ascorbate and pyruvate could protect D. vulgaris cells from Cr(VI)/Cr(III) toxicity.

  1. Expression of interferon-inducible recombinant human RNase L causes RNA degradation and inhibition of cell growth in Escherichia coli.

    PubMed

    Pandey, Mitali; Rath, Pramod C

    2004-04-30

    Interferon-inducible ribonuclease L (RNase L) is a unique ankyrin-repeat containing endoribonuclease activated by 2',5'-oligoadenylate (2-5A) cofactor leading to RNA degradation and apoptosis during antiviral response in mammalian cells. We report that expression of recombinant human RNase L (1-741 a.a.) caused RNA degradation and inhibition of cell growth in Escherichia coli in absence of exogenous 2-5A. On the contrary, expression of a homologous but dominant negative form of murine RNase L (1-656 a.a.), lacking the RNA binding and ribonuclease domain, did not show RNA degradation, rather it stimulated cell growth. Upon computational analysis by pBLAST search, a putative transcription factor (yahD, F64758, and NP_414852) from the E. coli genome showed highest homology (E value=1e(-17)) with 90-259 a.a. region of human RNase L due to ankyrin repeats with conserved GKT motifs. Ankyrin repeats 6-9 of RNase L are involved in 2-5A binding, dimerization, and activation of the ribonuclease. Thus, a biochemically active human RNase L in E. coli strongly suggests for a prokaryotic cell growth-inhibitory mechanism possibly through ankyrin-ankyrin interaction of YahD and RNase L leading to RNA degradation. The mammalian interferon-inducible RNase L and E. coli yahD protein may have common origin for the ankyrin repeats with 2-5A binding sites. Thus, RNA degradation and cell growth inhibition by recombinant human RNase L biochemically reconstituted mammalian cellular response to interferon in E. coli. RNase L has prokaryotic evolutionary history, it is not only an antiviral but also an antibacterial gene.

  2. Chronic Embolic Pulmonary Hypertension Caused by Pulmonary Embolism and Vascular Endothelial Growth Factor Inhibition.

    PubMed

    Neto-Neves, Evandro M; Brown, Mary B; Zaretskaia, Maria V; Rezania, Samin; Goodwill, Adam G; McCarthy, Brian P; Persohn, Scott A; Territo, Paul R; Kline, Jeffrey A

    2017-04-01

    Our understanding of the pathophysiological basis of chronic thromboembolic pulmonary hypertension (CTEPH) will be accelerated by an animal model that replicates the phenotype of human CTEPH. Sprague-Dawley rats were administered a combination of a single dose each of plastic microspheres and vascular endothelial growth factor receptor antagonist in polystyrene microspheres (PE) + tyrosine kinase inhibitor SU5416 (SU) group. Shams received volume-matched saline; PE and SU groups received only microspheres or SU5416, respectively. PE + SU rats exhibited sustained pulmonary hypertension (62 ± 13 and 53 ± 14 mmHg at 3 and 6 weeks, respectively) with reduction of the ventriculoarterial coupling in vivo coincident with a large decrement in peak rate of oxygen consumption during aerobic exercise, respectively. PE + SU produced right ventricular hypokinesis, dilation, and hypertrophy observed on echocardiography, and 40% reduction in right ventricular contractile function in isolated perfused hearts. High-resolution computed tomographic pulmonary angiography and Ki-67 immunohistochemistry revealed abundant lung neovascularization and cellular proliferation in PE that was distinctly absent in the PE + SU group. We present a novel rodent model to reproduce much of the known phenotype of CTEPH, including the pivotal pathophysiological role of impaired vascular endothelial growth factor-dependent vascular remodeling. This model may reveal a better pathophysiological understanding of how PE transitions to CTEPH in human treatments.

  3. Peptoids successfully inhibit the growth of gram negative E. coli causing substantial membrane damage

    PubMed Central

    Mojsoska, Biljana; Carretero, Gustavo; Larsen, Sylvester; Mateiu, Ramona Valentina; Jenssen, Håvard

    2017-01-01

    Peptoids are an alternative approach to antimicrobial peptides that offer higher stability towards enzymatic degradation. It is essential when developing new types of peptoids, that mimic the function of antimicrobial peptides, to understand their mechanism of action. Few studies on the specific mechanism of action of antimicrobial peptoids have been described in the literature, despite the plethora of studies on the mode of action of antimicrobial peptides. Here, we investigate the mechanism of action of two short cationic peptoids, rich in lysine and tryptophan side chain functionalities. We demonstrate that both peptoids are able to cause loss of viability in E. coli susceptible cells at their MIC (16–32 μg/ml) concentrations. Dye leakage assays demonstrate slow and low membrane permeabilization for peptoid 1, that is still higher for lipid compositions mimicking bacterial membranes than lipid compositions containing Cholesterol. At concentrations of 4 × MIC (64–128 μg/ml), pore formation, leakage of cytoplasmic content and filamentation were the most commonly observed morphological changes seen by SEM in E. coli treated with both peptoids. Flow cytometry data supports the increase of cell size as observed in the quantification analysis from the SEM images and suggests overall decrease of DNA per cell mass over time. PMID:28195195

  4. Expression of a TGF-beta1 inducible gene, TSC-36, causes growth inhibition in human lung cancer cell lines.

    PubMed

    Sumitomo, K; Kurisaki, A; Yamakawa, N; Tsuchida, K; Shimizu, E; Sone, S; Sugino, H

    2000-07-03

    TSC-36 (TGF-beta1-stimulated clone 36) is a TGF-beta1 inducible gene whose product is an extracellular glycoprotein that contains a single follistatin module. TSC-36 is highly expressed in the lung, but its physiological function is unknown. In an attempt to elucidate it, we investigated the effect of TSC-36 on proliferation of human lung cancer cell lines. We found a correlation between expression of TSC-36 and cell growth: TSC-36 mRNA was not detected in cells derived from small cell lung cancer (SCLC) cells, a highly aggressive neoplasm, but was detected in some non-small cell lung cancer (NSCLC) cells, a moderately aggressive neoplasm. This suggested an antiproliferative function for TSC-36. To address this question, NSCLC PC-14 cells, which express very low level of TSC-36 protein, were transfected with TSC-36 cDNA and the proliferative capacity of stable transfectants was determined by measuring the doubling time, colony forming activity in soft agar and the level of incorporation of (3)H-thymidine into DNA. Under normal culture conditions, the transfected cells showed a longer doubling time, lower plating efficiency and lower rate of DNA synthesis than the parental cells and the control neo transfectant cells. These findings suggested that expression of TSC-36 caused growth inhibition in human lung cancer cells.

  5. MicroRNA-16 inhibits feto-maternal angiogenesis and causes recurrent spontaneous abortion by targeting vascular endothelial growth factor

    PubMed Central

    Zhu, Yongsheng; Lu, Hong; Huo, Zhenghao; Ma, Zhanbin; Dang, Jie; Dang, Wei; Pan, Lin; Chen, Jing; Zhong, Huijun

    2016-01-01

    Recurrent spontaneous abortion (RSA) is a common health problem that affects women of reproductive age. Recent studies have indicated that microRNAs are important factors in miscarriage. This study investigated the role of miR-16 in regulating vascular endothelial growth factor (VEGF) expression and the pathogenesis of RSA. In this report, clinical samples revealed that miR-16 expression was significantly elevated in the villi and decidua of RSA patients. In vitro, miR-16 upregulation inhibited human umbilical vein endothelial cell proliferation, migration and tube formation. Conversely, the downregulation of miR-16 reversed these effects. In vivo, we demonstrated that abnormal miR-16 levels affect the weights of the placenta and embryo and the number of progeny and microvascular density, as well as cause recurrent abortions by controlling VEGF expression in pregnant mice. VEGF, a potential target gene of miR-16, was inversely correlated with miR-16 expression in the decidua of clinical samples. Furthermore, the luciferase reporter system demonstrated that miR-16 was found to directly downregulate the expression of VEGF by binding a specific sequence of its 3′-untranslated region (3′UTR). Collectively, these data strongly suggest that miR-16 regulates placental angiogenesis and development by targeting VEGF expression and is involved in the pathogenesis of RSA. PMID:27748453

  6. MicroRNA-16 inhibits feto-maternal angiogenesis and causes recurrent spontaneous abortion by targeting vascular endothelial growth factor.

    PubMed

    Zhu, Yongsheng; Lu, Hong; Huo, Zhenghao; Ma, Zhanbin; Dang, Jie; Dang, Wei; Pan, Lin; Chen, Jing; Zhong, Huijun

    2016-10-17

    Recurrent spontaneous abortion (RSA) is a common health problem that affects women of reproductive age. Recent studies have indicated that microRNAs are important factors in miscarriage. This study investigated the role of miR-16 in regulating vascular endothelial growth factor (VEGF) expression and the pathogenesis of RSA. In this report, clinical samples revealed that miR-16 expression was significantly elevated in the villi and decidua of RSA patients. In vitro, miR-16 upregulation inhibited human umbilical vein endothelial cell proliferation, migration and tube formation. Conversely, the downregulation of miR-16 reversed these effects. In vivo, we demonstrated that abnormal miR-16 levels affect the weights of the placenta and embryo and the number of progeny and microvascular density, as well as cause recurrent abortions by controlling VEGF expression in pregnant mice. VEGF, a potential target gene of miR-16, was inversely correlated with miR-16 expression in the decidua of clinical samples. Furthermore, the luciferase reporter system demonstrated that miR-16 was found to directly downregulate the expression of VEGF by binding a specific sequence of its 3'-untranslated region (3'UTR). Collectively, these data strongly suggest that miR-16 regulates placental angiogenesis and development by targeting VEGF expression and is involved in the pathogenesis of RSA.

  7. Vizantin inhibits bacterial adhesion without affecting bacterial growth and causes Streptococcus mutans biofilm to detach by altering its internal architecture.

    PubMed

    Takenaka, Shoji; Oda, Masataka; Domon, Hisanori; Ohsumi, Tatsuya; Suzuki, Yuki; Ohshima, Hayato; Yamamoto, Hirofumi; Terao, Yutaka; Noiri, Yuichiro

    2016-11-11

    An ideal antibiofilm strategy is to control both in the quality and quantity of biofilm while maintaining the benefits derived from resident microflora. Vizantin, a recently developed immunostimulating compound, has also been found to have antibiofilm property. This study evaluated the influence on biofilm formation of Streptococcus mutans in the presence of sulfated vizantin and biofilm development following bacterial adhesion on a hydroxyapatite disc coated with sulfated vizantin. Supplementation with sulfated vizantin up to 50 μM did not affect either bacterial growth or biofilm formation, whereas 50 μM sulfated vizantin caused the biofilm to readily detach from the surface. Sulfated vizantin at the concentration of 50 μM upregulated the expression of the gtfB and gtfC genes, but downregulated the expression of the gtfD gene, suggesting altered architecture in the biofilm. Biofilm development on the surface coated with sulfated vizantin was inhibited depending on the concentration, suggesting prevention from bacterial adhesion. Among eight genes related to bacterial adherence in S. mutans, expression of gtfB and gtfC was significantly upregulated, whereas the expression of gtfD, GbpA and GbpC was downregulated according to the concentration of vizantin, especially with 50 μM vizantin by 0.8-, 0.4-, and 0.4-fold, respectively. These findings suggest that sulfated vizantin may cause structural degradation as a result of changing gene regulation related to bacterial adhesion and glucan production of S. mutans. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Transforming Growth Factor β Blocks Tec Kinase Phosphorylation, Ca2+ Influx, and NFATc Translocation Causing Inhibition of T Cell Differentiation

    PubMed Central

    Chen, Chang-Hung; Seguin-Devaux, Carole; Burke, Nancy A.; Oriss, Timothy B.; Watkins, Simon C.; Clipstone, Neil; Ray, Anuradha

    2003-01-01

    Transforming growth factor (TGF)-β inhibits T cell proliferation and differentiation. TGF-β has been shown to inhibit the expression of transcription factors such as GATA-3 and T-bet that play important roles in T cell differentiation. Here we show that TGF-β inhibits T cell differentiation at a more proximal step. An early event during T cell activation is increased intracellular calcium levels. Calcium influx in activated T cells and the subsequent activation of transcription factors such as NFATc, events essential for T cell differentiation, are modulated by the Tec kinases that are downstream of the T cell receptor and CD28. We show that in stimulated CD4+ T cells, TGF-β inhibits phosphorylation and activation of the Tec kinase Itk, increase in intracellular Ca2+ levels, NFATc translocation, and activation of the mitogen-activated protein kinase ERK that together regulate T cell differentiation. Our studies suggest that by inhibiting Itk, and consequently Ca2+ influx, TGF-β limits T cell differentiation along both the Th1 and Th2 lineages. PMID:12810687

  9. Secreted phosphoprotein 24 kD (Spp24) inhibits growth of human pancreatic cancer cells caused by BMP-2

    SciTech Connect

    Li, Chen-Shuang; Tian, Haijun; Zou, Min; Zhao, Ke-Wei; Li, Yawei; Lao, Lifeng; Brochmann, Elsa J.; Duarte, M. Eugenia L.; Daubs, Michael D.; Zhou, Yan-Heng; Murray, Samuel S.; Wang, Jeffrey C.

    2015-10-16

    The emerging role of bone morphogenetic proteins (BMPs) in the initiation and progression of multiple cancers has drawn great attention in cancer research. In this study, we report that BMP-2 can promote the proliferation of the pancreatic tumor cell line, PANC-1. Secreted phosphoprotein 24 kD (Spp24), a BMP binding protein, did not affect the proliferation of the cells but promoted the apoptosis of the cells in vitro. In a xeneograft tumor model using PANC-1 cells, BMP-2 dramatically promoted tumor growth, while Spp24 not only abolished the effect of BMP-2, but also dramatically induced tumor shrinking when used alone. Activation of Smad1/5/8 participated in this process as demonstrated by immunohistochemical staining of phosphorylated Smad 1/5/8. We conclude that Spp24 can be developed into a therapeutic agent that could be employed in clinical situations where the inhibition of BMPs and related proteins is advantageous. - Highlights: • Spp24 effectively inhibited the in vivo tumor growth of PANC-1. • BMP-2 dramatically promoted tumor growth by promoting PANC-1 proliferation. • Spp24 abolished the tumor growth effect of BMP-2 by promoting PANC-1 apoptosis. • Spp24 may be a candidate as a therapeutic agent of pancreatic cancer.

  10. Methanolic extracts of Aloe secundiflora Engl. inhibits in vitro growth of tuberculosis and diarrhea-causing bacteria

    PubMed Central

    Mariita, Richard M.; Orodho, John A.; Okemo, Paul O.; Kirimuhuzya, Claude; Otieno, Joseph N.; Magadula, Joseph J.

    2011-01-01

    Background: The emergence of resistance to antimicrobials by pathogens has reached crisis levels, calling for identification of alternative means to combat diseases. Objective: To determine antimicrobial activity of crude methanolic extract of Aloe secundiflora Engl. from Lake Victoria region of Kenya. Materials and Methods: Extract was tested against four strains of mycobacteria (Mycobacterium tuberculosis, M. kansasii, M. fortuitum and M. smegmatis), Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and a fungus Candida albicans. activity of the extract was determined using BACTEC™ MGIT™ 960 system. General antibacterial and antifungal activity was determined using standard procedures: zones of inhibition, Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal/Fungicidal Concentrations (MBCs/MFCs). Results: The extract was potent against M. fortuitum, M. smegmatis and M. kansasii where it completely inhibited growth (Zero growth units (GUs)) in all the extract concentrations used. It gave strong antimycobacterial activity (157 GUs) against M. tuberculosis. It showed strong antimicrobial activity (P≤0.05), giving inhibition zones ≥9.00 mm against most microorganisms, such as P. aeruginosa (MIC 9.375 mg mL-1 and MBC of 18.75 mg mL-1), E. coli (both MIC and MBC of 18.75 mg mL-1), S. aureus and S. typhi (both with MIC and MBC of 37.5 mg mL-1). Preliminary phytochemistry revealed presence of terpenoids, flavonoids and tannins. Conclusion: The data suggests that Aloe secundiflora could be a rich source of antimicrobial agents. The result gives scientific backing to its use by the local people of Lake Victoria region of Kenya, in the management of conditions associated with the tested microorganisms. PMID:21772752

  11. Overexpression of protein kinase C in HT29 colon cancer cells causes growth inhibition and tumor suppression.

    PubMed Central

    Choi, P M; Tchou-Wong, K M; Weinstein, I B

    1990-01-01

    By using a retrovirus-derived vector system, we generated derivatives of the human colon cancer cell line HT29 that stably overexpress a full-length cDNA encoding the beta 1 isoform of rat protein kinase C (PKC). Two of these cell lines, PKC6 and PKC7, displayed an 11- to 15-fold increase in PKC activity when compared with the C1 control cell line that carries the vector lacking the PKC cDNA insert. Both of the overexpresser cell lines exhibited striking alterations in morphology when exposed to the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Following exposure to TPA, PKC6 and PKC7 cells displayed increased doubling time, decreased saturation density, and loss of anchorage-independent growth in soft agar; but these effects were not seen with the C1 cells. Also, in contrast to the control cells, the PKC-overproducing cells failed to display evidence of differentiation, as measured by alkaline phosphatase activity, when exposed to sodium butyrate. In addition, the PKC-overexpresser cells displayed decreased tumorigenicity in nude mice, even in the absence of treatment with TPA. These results provide the first direct evidence that PKC can inhibit tumor cell growth. Thus, in some tumors, PKC might act as a growth-suppressor gene. Images PMID:2388620

  12. Exposure of breast cancer cells to a subcytotoxic dose of apigenin causes growth inhibition, oxidative stress, and hypophosphorylation of Akt.

    PubMed

    Harrison, Megan E; Power Coombs, Melanie R; Delaney, Leanne M; Hoskin, David W

    2014-10-01

    Epidemiological studies show that fruit- and vegetable-rich diets are associated with a reduced risk of developing certain forms of cancer, including breast cancer. In this study we demonstrate that a subcytotoxic concentration of apigenin, which is a flavone found at high concentrations in parsley, onions, grapefruit, oranges, and chamomile tea, inhibited DNA synthesis in a panel of human breast cancer cell lines (MDA-MB-231, MBA-MB-468, MCF-7, SK-BR-3). Decreased proliferation of MDA-MB-468 cells in the presence of apigenin was associated with G2/M phase cell cycle arrest and the production of reactive oxygen species. Apigenin-treated MDA-MB-468 cells also showed reduced phosphorylation of Akt (protein kinase B), which is an essential effector serine/threonine kinase in the phosphatidylinositide 3-kinase pathway that promotes tumor growth and progression. However, exposure to the antioxidant reduced glutathione failed to reverse apigenin-mediated inhibition of Akt phosphorylation and cell proliferation, indicating that these effects were not due to oxidative stress. Taken together, these findings suggest that low-dose apigenin has the potential to slow or prevent breast cancer progression.

  13. Elongation Factor 1A Is the Target of Growth Inhibition in Yeast Caused by Legionella pneumophila Glucosyltransferase Lgt1*

    PubMed Central

    Belyi, Yury; Tartakovskaya, Dina; Tais, Arlette; Fitzke, Edith; Tzivelekidis, Tina; Jank, Thomas; Rospert, Sabine; Aktories, Klaus

    2012-01-01

    Legionella is a pathogenic Gram-negative bacterium that can multiply inside of eukaryotic cells. It translocates numerous bacterial effector proteins into target cells to transform host phagocytes into a niche for replication. One effector of Legionella pneumophila is the glucosyltransferase Lgt1, which modifies serine 53 in mammalian elongation factor 1A (eEF1A), resulting in inhibition of protein synthesis and cell death. Here, we demonstrate that similar to mammalian cells, Lgt1 was severely toxic when produced in yeast and effectively inhibited in vitro protein synthesis. Saccharomyces cerevisiae strains, which were deleted of endogenous eEF1A but harbored a mutant eEF1A not glucosylated by Lgt1, were resistant toward the bacterial effector. In contrast, deletion of Hbs1, which is also an in vitro substrate of the glucosyltransferase, did not influence the toxic effects of Lgt1. Serial mutagenesis in yeast showed that Phe54, Tyr56 and Trp58, located immediately downstream of serine 53 of eEF1A, are essential for the function of the elongation factor. Replacement of serine 53 by glutamic acid, mimicking phosphorylation, produced a non-functional eEF1A, which failed to support growth of S. cerevisiae. Our data indicate that Lgt1-induced lethal effect in yeast depends solely on eEF1A. The region of eEF1A encompassing serine 53 plays a critical role in functioning of the elongation factor. PMID:22685293

  14. Inhibiting Polo-like kinase 1 causes growth reduction and apoptosis in pediatric acute lymphoblastic leukemia cells.

    PubMed

    Hartsink-Segers, Stefanie A; Exalto, Carla; Allen, Matthew; Williamson, Daniel; Clifford, Steven C; Horstmann, Martin; Caron, Huib N; Pieters, Rob; Den Boer, Monique L

    2013-10-01

    This study investigated Polo-like kinase 1, a mitotic regulator often over-expressed in solid tumors and adult hematopoietic malignancies, as a potential new target in the treatment of pediatric acute lymphoblastic leukemia. Polo-like kinase 1 protein and Thr210 phosphorylation levels were higher in pediatric acute lymphoblastic leukemia (n=172) than in normal bone marrow mononuclear cells (n=10) (P<0.0001). High Polo-like kinase 1 protein phosphorylation, but not expression, was associated with a lower probability of event-free survival (P=0.042) and was a borderline significant prognostic factor (P=0.065) in a multivariate analysis including age and initial white blood cell count. Polo-like kinase 1 was necessary for leukemic cell survival, since short hairpin-mediated Polo-like kinase 1 knockdown in acute lymphoblastic leukemia cell lines inhibited cell proliferation by G2/M cell cycle arrest and induced apoptosis through caspase-3 and poly (ADP-ribose) polymerase cleavage. Primary patient cells with a high Polo-like kinase 1 protein expression were sensitive to the Polo-like kinase 1-specific inhibitor NMS-P937 in vitro, whereas cells with a low expression and normal bone marrow cells were resistant. This sensitivity was likely not caused by Polo-like kinase 1 mutations, since only one new mutation (Ser335Arg) was found by 454-sequencing of 38 pediatric acute lymphoblastic leukemia cases. This mutation did not affect Polo-like kinase 1 expression or NMS-P937 sensitivity. Together, these results indicate a pivotal role for Polo-like kinase 1 in pediatric acute lymphoblastic leukemia and show potential for Polo-like kinase 1-inhibiting drugs as an addition to current treatment strategies for cases expressing high Polo-like kinase 1 levels.

  15. Inhibition of placental ornithine decarboxylase by DL-alpha-difluoro-methyl ornithine causes fetal growth restriction in rat.

    PubMed

    Ishida, Makoto; Hiramatsu, Yuji; Masuyama, Hisashi; Mizutani, Yasushi; Kudo, Takafumi

    2002-02-08

    The roles of polyamines in intrauterine growth restriction (IUGR) is studied. The DL-alpha-difluoromethyl ornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC) which is a rate limiting enzyme of polyamine synthesis was administrated to pregnant rats so that we obtained rat fetuses with IUGR. The changes of maternal nutrition, damage of the placenta, and the direct effect of DFMO on the fetus were examined in this IUGR model. Administration of DFMO did not induced changes of maternal nutrition except for triglyceride and the fetal metabolic state. But the placental weight, ODC activity, and DNA in the placenta were decreased significantly. The ODC activity in the total placenta decreased to less than 10% of that of the control. Depression of ODC activity in the placenta may be the major cause of IUGR induced by DFMO administration, and polyamines play important roles to carry pregnancy.

  16. Small molecule inhibition of polo-like kinase 1 by volasertib (BI 6727) causes significant melanoma growth delay and regression in vivo.

    PubMed

    Cholewa, Brian D; Ndiaye, Mary A; Huang, Wei; Liu, Xiaoqi; Ahmad, Nihal

    2017-01-28

    The objective of this study was to determine the therapeutic potential of polo-like kinase 1 (Plk1) inhibition in melanoma, in vivo. Employing Vectra technology, we assessed the Plk1 expression profile in benign nevi, malignant (stages I-IV) and metastatic melanomas. We found a significant elevation of Plk1 immunostaining in melanoma tissues. Further, a second generation small molecule Plk1 inhibitor, BI 6727, resulted in reductions in growth, viability and clonogenic survival, as well as an increase in apoptosis of A375 and Hs 294T melanoma cells. BI 6727 treatment also resulted in a G2/M-as well as S-phase cell cycle arrest in melanoma cells. Importantly, BI 6727 (intravenous injection; 10 and 25 mg/kg body weight) treatment resulted in significant tumor growth delay and regression in vivo in A375-and Hs 294T-implanted xenografts in athymic nude mice. These anti-melanoma effects were accompanied with a decreased cellular proliferation (Ki-67 staining) and induction of apoptosis (caspase 3 activation). In addition, BI 6727 treatment caused a marked induction of p53 and p21 in vitro as well as in vivo. Overall, we suggest that Plk1 inhibition may be a useful approach as a monotherapy as well as in combination with other existing therapeutics, for melanoma management. Published by Elsevier Ireland Ltd.

  17. Reduced allelopathic inhibition of lettuce (Lactuca sativa) growth caused by velvet bean (Mucuna pruriens) under 3D-clinorotation.

    PubMed

    Tomita-Yokotani, Kaori; Fujii, Yoshiharu; Hashimoto, Hirofumi; Yamashita, Masamichi

    2003-06-01

    Allelopathy between Mucuna pruriens (velvet bean) and Lactuca sativa (lettuce) was studied under 3D-clinorotation. Growth of both roots and shoots of lettuce seedlings was suppressed by the presence of velvet bean. The degree of suppression was less on the clinostat compared to the normal static earth gravity. L-DOPA (L-3, 4-dihydroxyphenylalanine) is known to be a major substance in allelopathy of velvet bean. Amount of L-DOPA diffused out from a sintered filter paper into agar medium was compared between clinorotation and control group, and found no significant difference. It was concluded that some factors related to release, transport, and sensing phenomena of allelopathic substances may be responsible to the new findings in this study.

  18. Carvone and perillaldehyde interfere with the serum-induced formation of filamentous structures in Candida albicans at substantially lower concentrations than those causing significant inhibition of growth.

    PubMed

    McGeady, Paul; Wansley, Daniel L; Logan, David A

    2002-07-01

    Carvone and perillaldehyde were shown to inhibit the transformation of Candida albicans to a filamentous form at concentrations far lower and more biologically relevant than the concentrations necessary to inhibit growth. This morphological transformation is associated with C. albicans pathogenicity; hence these naturally occurring monoterpenes are potential lead compounds in the development of therapeutic agents against C. albicans infection.

  19. Biochemical effects and growth inhibition in MCF-7 cells caused by novel sulphonamido oxa-polyamine derivatives.

    PubMed

    Pavlov, V; Lin, P Kong Thoo; Rodilla, V

    2002-04-01

    The novel polyamine derivatives sulphonamido oxa-spermine (oxa-Spm) and sulphonamido oxa-spermidine (oxa-Spd) exhibited rapid cytotoxic action towards MCF-7 human breast cancer cells with IC50 values of 4.35 and 6.47 pM, respectively, after 24-h drug exposure. Neither compound is a substrate of serum amine oxidase. Both oxa-Spm and oxa-Spd caused cell shrinkage, as determined by phase-contrast microscopy. After incubation with 10 microM of either compound for 8 h, the cells underwent chromatin condensation and nuclear fragmentation. However, no clear DNA ladder was obtained by electrophoresis. The sulphonamido oxa-polyamine derivatives and especially oxa-Spd enhanced the activity of polyamine oxidase (PAO), an enzyme capable of oxidising N1-acetylated spermine and spermidine to spermidine and putrescine, respectively, generating cytotoxic H2O2 and 3-acetamidopropanal as by-products. The intracellular polyamine content was only marginally reduced in response to drug treatment. In conclusion, our data show that these novel sulphonamido oxa-polyamine derivatives possess high cytotoxic activity against MCF-7 cells and indicate that induction of PAO may mediate their cytotoxicity via apoptosis.

  20. Growth Inhibition by External Potassium of Escherichia coli Lacking PtsN (EIIANtr) Is Caused by Potassium Limitation Mediated by YcgO

    PubMed Central

    Sharma, Ravish; Shimada, Tomohiro; Mishra, Vinod K.; Upreti, Suchitra

    2016-01-01

    ABSTRACT The absence of PtsN, the terminal phosphoacceptor of the phosphotransferase system comprising PtsP-PtsO-PtsN, in Escherichia coli confers a potassium-sensitive (Ks) phenotype as the external K+ concentration ([K+]e) is increased above 5 mM. A growth-inhibitory increase in intracellular K+ content, resulting from hyperactivated Trk-mediated K+ uptake, is thought to cause this Ks. We provide evidence that the Ks of the ΔptsN mutant is associated with K+ limitation. Accordingly, the moderate Ks displayed by the ΔptsN mutant was exacerbated in the absence of the Trk and Kup K+ uptake transporters and was associated with reduced cellular K+ content. Conversely, overproduction of multiple K+ uptake proteins suppressed the Ks. Expression of PtsN variants bearing the H73A, H73D, and H73E substitutions of the phosphorylation site histidine of PtsN complemented the Ks. Absence of the predicted inner membrane protein YcgO (also called CvrA) suppressed the Ks, which was correlated with elevated cellular K+ content in the ΔptsN mutant, but the ΔptsN mutation did not alter YcgO levels. Heterologous overexpression of ycgO also led to Ks that was associated with reduced cellular K+ content, exacerbated by the absence of Trk and Kup and alleviated by overproduction of Kup. Our findings are compatible with a model that postulates that Ks in the ΔptsN mutant occurs due to K+ limitation resulting from activation of K+ efflux mediated by YcgO, which may be additionally stimulated by [K+]e, implicating a role for PtsN (possibly its dephosphorylated form) as an inhibitor of YcgO activity. IMPORTANCE This study examines the physiological link between the phosphotransferase system comprising PtsP-PtsO-PtsN and K+ ion metabolism in E. coli. Studies on the physiological defect that renders an E. coli mutant lacking PtsN to be growth inhibited by external K+ indicate that growth impairment results from cellular K+ limitation that is mediated by YcgO, a predicted inner membrane

  1. Menaquinone Analogs Inhibit Growth of Bacterial Pathogens

    PubMed Central

    Merriman, Joseph A.; Salgado-Pabón, Wilmara; Mueller, Elizabeth A.; Spaulding, Adam R.; Vu, Bao G.; Chuang-Smith, Olivia N.; Kohler, Petra L.; Kirby, John R.

    2013-01-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents. PMID:23959313

  2. Menaquinone analogs inhibit growth of bacterial pathogens.

    PubMed

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  3. A polyphenolic fraction from grape seeds causes irreversible growth inhibition of breast carcinoma MDA-MB468 cells by inhibiting mitogen-activated protein kinases activation and inducing G1 arrest and differentiation.

    PubMed

    Agarwal, C; Sharma, Y; Zhao, J; Agarwal, R

    2000-07-01

    In recent years, significant emphasis is being placed on identifying naturally occurring cancer preventive and interventive agents. In this regard, a polyphenolic fraction isolated from grape seeds (hereafter referred as GSP) has recently been shown by us and others to prevent tumorigenesis in mouse skin models. Chemical analysis of GSP has shown that it is largely constituted with procyanidins that are strong antioxidants. Breast cancer is the most common invasive malignancy and the second leading cause of cancer-related deaths in United States women. Accordingly, here we investigated the effect of GSP on mitogenic signaling and regulators of cell cycle and apoptosis as molecular targets for the growth arrest, apoptotic death, and/or differentiation of estrogen-independent MDA-MB468 human breast carcinoma cells. Treatment of cells with GSP (at 25-, 50-, and 75-microg/ml doses for 1-3 days) resulted in a highly significant inhibition (90% to complete, P < 0.001) of constitutive activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase1/2 in a dose-dependent manner after 72 h of treatment. Whereas GSP treatment of cells did not show a conclusive effect on MAPK/ JNK1 activation, a moderate to highly significant inhibition (15-70%, P < 0.1-0.001) of constitutive activation of MAPK/p38 was also observed in a dose-dependent manner as early as 24 h of GSP treatment. GSP-treated cells also showed a strong induction (1.7-2.7 fold, P < 0.001) of cyclin-dependent kinase inhibitor Cip1/p21 and a decrease (10-50%, P < 0.1-0.001) in cyclin-dependent kinase 4. Consistent with these findings, GSP-treated cells resulted in their accumulation in G1 phase of the cell cycle in a dose-dependent manner. An irreversible growth inhibition (44-88%, P < 0.001) was also observed in 50 and 75 microg/ml GSP-treated cells in a time-dependent manner. Additional studies assessing the biological fate of GSP-treated cells showed that they do not undergo

  4. Human lysozyme expressed in the mammary gland of transgenic dairy goats can inhibit the growth of bacteria that cause mastitis and the cold-spoilage of milk.

    PubMed

    Maga, Elizabeth A; Cullor, James S; Smith, Wayne; Anderson, Gary B; Murray, James D

    2006-01-01

    The addition of human milk components with intrinsic antimicrobial activity to livestock milk by genetic engineering has the potential to benefit milk safety and production as well as the health of the lactating animal. As a model for the dairy cow, we generated transgenic goats that expressed human lysozyme in their milk at 68% of the levels found in human milk. Milk from these transgenic animals had a bacteriostatic effect on both in vitro and in vivo growth of several microorganisms important to the dairy industry. In vitro, milk from transgenic animals was capable of slowing the growth of mastitis-causing strains of Escherichia coli (P < 0.02) and Staphylococcus aureus (P < 0.05) as well as the cold-spoilage organism Pseudomonas fragi (P < 0.02). The growth of an organism involved in cheese-making, Lactococcus lactis, was not affected by the presence of lysozyme in milk. The supplementation of control milk with purified lysozyme did not achieve the same inhibitory effect as milk from transgenic animals. In vivo, milk from transgenic animals supported less bacterial growth than control milk. This transgenic model demonstrates the possibilities offered by genetic engineering to enhance the antimicrobial nature of milk and the udder.

  5. Suppression of S-adenosylmethionine decarboxylase activity is a major cause for high-temperature inhibition of pollen germination and tube growth in tomato (Lycopersicon esculentum Mill.).

    PubMed

    Song, Jianjun; Nada, Kazuyoshi; Tachibana, Shoji

    2002-06-01

    Possible involvement of impaired polyamine biosynthesis in the poor performance of tomato pollen (Lycopersicon esculentum Mill.) at high temperatures was investigated. Incubation of pollen at 38 degrees C suppressed the increase of S-adenosylmethionine decarboxylase (SAMDC) activity in germinating pollen with little influence on arginine decarboxylase activity. Consequently, spermidine and spermine content in the pollen did not increase at 38 degrees C, while putrescine content increased at both 25 degrees C and 38 degrees C. High-temperature inhibition of pollen germination was alleviated by the addition of spermidine or spermine but not of putrescine to the germination medium. Cycloheximide inhibited SAMDC activity in parallel with pollen germination at 25 degrees C, whereas actinomycin D had no effect on either of them, indicating that enhanced SAMDC activity is associated with de novo protein synthesis. Incubation of crude enzyme extracts at 40 degrees C for 1 h did not affect SAMDC. In addition, high temperatures did not enhance protease activity in germinating pollen. These results indicate that low activity of SAMDC, probably due to impaired protein synthesis or functional enzyme formation, is a major cause for the poor performance of tomato pollen at high temperatures.

  6. Well having inhibited microbial growth

    DOEpatents

    Lee, Brady D.; Dooley, Kirk J.

    2006-08-15

    The invention includes methods of inhibiting microbial growth in a well. A packing material containing a mixture of a first material and an antimicrobial agent is provided to at least partially fill a well bore. One or more access tubes are provided in an annular space around a casing within the well bore. The access tubes have a first terminal opening located at or above a ground surface and have a length that extends from the first terminal opening at least part of the depth of the well bore. The access tubes have a second terminal opening located within the well bore. An antimicrobial material is supplied into the well bore through the first terminal opening of the access tubes. The invention also includes well constructs.

  7. A mutation in GDP-mannose pyrophosphorylase causes conditional hypersensitivity to ammonium, resulting in Arabidopsis root growth inhibition, altered ammonium metabolism, and hormone homeostasis.

    PubMed

    Barth, Carina; Gouzd, Zachary A; Steele, Hilary P; Imperio, Ryan M

    2010-01-01

    Ascorbic acid (AA) is an antioxidant fulfilling a multitude of cellular functions. Given its pivotal role in maintaining the rate of cell growth and division in the quiescent centre of the root, it was hypothesized that the AA-deficient Arabidopsis thaliana mutants vtc1-1, vtc2-1, vtc3-1, and vtc4-1 have altered root growth. To test this hypothesis, root development was studied in the wild type and vtc mutants grown on Murashige and Skoog medium. It was discovered, however, that only the vtc1-1 mutant has strongly retarded root growth, while the other vtc mutants exhibit a wild-type root phenotype. It is demonstrated that the short-root phenotype in vtc1-1 is independent of AA deficiency and oxidative stress. Instead, vtc1-1 is conditionally hypersensitive to ammonium (NH(4)(+)). To provide new insights into the mechanism of NH(4)(+) sensitivity in vtc1-1, root development, NH(4)(+) content, glutamine synthetase (GS) activity, glutamate dehydrogenase activity, and glutamine content were assessed in wild-type and vtc1-1 mutant plants grown in the presence and absence of high NH(4)(+) and the GS inhibitor MSO. Since VTC1 encodes a GDP-mannose pyrophosphorylase, an enzyme generating GDP-mannose for AA biosynthesis and protein N-glycosylation, it was also tested whether protein N-glycosylation is affected in vtc1-1. Furthermore, since root development requires the action of a variety of hormones, it was investigated whether hormone homeostasis is linked to NH(4)(+) sensitivity in vtc1-1. Our data suggest that NH(4)(+) hypersensitivity in vtc1-1 is caused by disturbed N-glycosylation and that it is associated with auxin and ethylene homeostasis and/or nitric oxide signalling.

  8. A mutation in GDP-mannose pyrophosphorylase causes conditional hypersensitivity to ammonium, resulting in Arabidopsis root growth inhibition, altered ammonium metabolism, and hormone homeostasis

    PubMed Central

    Barth, Carina; Gouzd, Zachary A.; Steele, Hilary P.; Imperio, Ryan M.

    2010-01-01

    Ascorbic acid (AA) is an antioxidant fulfilling a multitude of cellular functions. Given its pivotal role in maintaining the rate of cell growth and division in the quiescent centre of the root, it was hypothesized that the AA-deficient Arabidopsis thaliana mutants vtc1-1, vtc2-1, vtc3-1, and vtc4-1 have altered root growth. To test this hypothesis, root development was studied in the wild type and vtc mutants grown on Murashige and Skoog medium. It was discovered, however, that only the vtc1-1 mutant has strongly retarded root growth, while the other vtc mutants exhibit a wild-type root phenotype. It is demonstrated that the short-root phenotype in vtc1-1 is independent of AA deficiency and oxidative stress. Instead, vtc1-1 is conditionally hypersensitive to ammonium (NH4+). To provide new insights into the mechanism of NH4+ sensitivity in vtc1-1, root development, NH4+ content, glutamine synthetase (GS) activity, glutamate dehydrogenase activity, and glutamine content were assessed in wild-type and vtc1-1 mutant plants grown in the presence and absence of high NH4+ and the GS inhibitor MSO. Since VTC1 encodes a GDP-mannose pyrophosphorylase, an enzyme generating GDP-mannose for AA biosynthesis and protein N-glycosylation, it was also tested whether protein N-glycosylation is affected in vtc1-1. Furthermore, since root development requires the action of a variety of hormones, it was investigated whether hormone homeostasis is linked to NH4+ sensitivity in vtc1-1. Our data suggest that NH4+ hypersensitivity in vtc1-1 is caused by disturbed N-glycosylation and that it is associated with auxin and ethylene homeostasis and/or nitric oxide signalling. PMID:20007685

  9. Timing of growth inhibition following shoot inversion in Pharbitis nil

    NASA Technical Reports Server (NTRS)

    Abdel-Rahman, A. M.; Cline, M. G.

    1989-01-01

    Shoot inversion in Pharbitis nil results in the enhancement of ethylene production and in the inhibition of elongation in the growth zone of the inverted shoot. The initial increase in ethylene production previously was detected within 2 to 2.75 hours after inversion. In the present study, the initial inhibition of shoot elongation was detected within 1.5 to 4 hours with a weighted mean of 2.4 hours. Ethylene treatment of upright shoots inhibited elongation in 1.5 hours. A cause and effect relationship between shoot inversion-enhanced ethylene production and inhibition of elongation cannot be excluded.

  10. Improvement of Parameter Estimations in Tumor Growth Inhibition Models on Xenografted Animals: Handling Sacrifice Censoring and Error Caused by Experimental Measurement on Larger Tumor Sizes.

    PubMed

    Pierrillas, Philippe B; Tod, Michel; Amiel, Magali; Chenel, Marylore; Henin, Emilie

    2016-09-01

    The purpose of this study was to explore the impact of censoring due to animal sacrifice on parameter estimates and tumor volume calculated from two diameters in larger tumors during tumor growth experiments in preclinical studies. The type of measurement error that can be expected was also investigated. Different scenarios were challenged using the stochastic simulation and estimation process. One thousand datasets were simulated under the design of a typical tumor growth study in xenografted mice, and then, eight approaches were used for parameter estimation with the simulated datasets. The distribution of estimates and simulation-based diagnostics were computed for comparison. The different approaches were robust regarding the choice of residual error and gave equivalent results. However, by not considering missing data induced by sacrificing the animal, parameter estimates were biased and led to false inferences in terms of compound potency; the threshold concentration for tumor eradication when ignoring censoring was 581 ng.ml(-1), but the true value was 240 ng.ml(-1).

  11. Fractionation of grape seed extract and identification of gallic acid as one of the major active constituents causing growth inhibition and apoptotic death of DU145 human prostate carcinoma cells.

    PubMed

    Veluri, Ravikanth; Singh, Rana P; Liu, Zhengjie; Thompson, John A; Agarwal, Rajesh; Agarwal, Chapla

    2006-07-01

    The anti-cancer efficacy of grape seed extract (GSE) against prostate cancer (PCA) via its anti-proliferative, pro-apoptotic and anti-angiogenic activities in both cell culture and animal models have recently been described by us. GSE is a complex mixture containing gallic acid (GA), catechin (C), epicatechin (EC) and several oligomers (procyanidins) of C and/or EC, some of which are esterified to GA. To determine which components are most active against PCA, an ethyl acetate extract of GSE was separated by reverse-phase high-performance liquid chromatography (HPLC) into three fractions. Fraction 1 was far more effective than others in causing growth inhibition and apoptotic death of human PCA DU145 cells. Of the components in this fraction, GA showed a very strong dose- and time-dependent growth inhibition and apoptotic death of DU145 cells, but C and procyanidins B1 (EC-C dimer), B2 (EC-EC dimer) and B3 (C-C dimer) were nearly ineffective. Mechanistic studies demonstrated a strong caspase-9, caspase-3 and poly (ADP-ribose) polymerase (PARP) cleavages by GA in DU145 cells. Procyanidin oligomers eluting in HPLC Fractions 2 and 3 were obtained in larger quantities by separating GSE into eight fractions (I-VIII) on a gel filtration column. All fractions were analyzed by HPLC-UV and negative-ion electrospray mass spectrometry. Fractions I-III contained the active compound GA and inactive components C, EC, B1 and B2. Fraction IV contained other dimers and a dimer-GA ester and was also less active than GSE in DU145 cells. Fractions V-VIII, however, caused significant growth inhibition and apoptosis with the highest activity present in the later fractions that contained procyanidin trimers and GA esters of dimers and trimers. Together, these observations identify GA as one of the major active constituents in GSE. Several procyanidins, however, and especially the gallate esters of dimers and trimers also may be efficacious against PCA and merit further investigation.

  12. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice

    PubMed Central

    Kim, Sung-Il; Song, Jong Tae; Jeong, Jin-Yong; Seo, Hak Soo

    2016-01-01

    Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects. PMID:26879887

  13. Growth suppression caused by corticosteroid eye drops.

    PubMed

    Wolthers, Ole D

    2011-01-01

    Scarce data on systemic activity of corticosteroid eye drops are available in children. Two weeks treatment with fluorometholone eye drops in a case series of five children caused growth suppression detected by knemometry. The suppression had no impact on height growth during the following year.

  14. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

    SciTech Connect

    Chang, Cheng-Yi; Kuan, Yu-Hsiang; Ou, Yen-Chuan; Li, Jian-Ri; Wu, Chih-Cheng; Pan, Pin-Ho; Chen, Wen-Ying; Huang, Hsuan-Yi; Chen, Chun-Jung

    2014-09-10

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK.

  15. A novel vitamin D3 analog, 22-oxa-1,25-dihydroxyvitamin D3, inhibits the growth of human breast cancer in vitro and in vivo without causing hypercalcemia.

    PubMed

    Abe, J; Nakano, T; Nishii, Y; Matsumoto, T; Ogata, E; Ikeda, K

    1991-08-01

    Although 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] has been shown to inhibit the growth of certain malignant cells, its hypercalcemic effect has prevented clinical application. We have recently developed a novel vitamin D3 analog, 22-oxa-1,25-(OH)2D3 (OCT), that is capable of promoting differentiation and inhibiting proliferation without inducing hypercalcemia. The present study was undertaken to determine whether OCT could be applied for the treatment of breast cancer with or without estrogen receptor (ER). OCT inhibited the proliferation of both ER-positive (MCF-7, T-47D, and ZR-75-1) and ER-negative breast cancer cells (MDA-MB-231 and BT-20) in vitro in a time- and dose-dependent manner, as determined by cell number and [3H]thymidine uptake. The antiproliferative effect was observed with a concentration as low as 10(-11) M OCT, and treatment of MCF-7 cells with 10(-8) M OCT for 8 days caused more than a 50% reduction in cell number compared with that of vehicle-treated cells. OCT was approximately 1 order of magnitude more potent than 1,25-(OH)2D3 in inhibiting the proliferation of MCF-7 cells. The in vivo effect of OCT was examined in athymic mice implanted with ER-negative MX-1 tumor, which was established as the xenograft derived from human breast carcinoma. Intratumor administration of OCT three times a week remarkably delayed the growth of MX-1 tumor in a time- and dose-dependent manner. The antitumor effect of 1 microgram/kg BW OCT was greater than that of 500 microgram/kg BW adriamycin, and the relative tumor weights in each group on day 26 were 29.7% and 50.5% of that in the vehicle-treated group, respectively. The effects of OCT and adriamycin were additive, and the relative tumor weight after 26 days of combined treatment was 21.7% of that in the vehicle-treated group. Oral administration of OCT was also effective, and the relative tumor weight in the OCT-treated group (1 microgram/kg BW) was 54.6 +/- 0.1% (mean +/- SEM) of that in the vehicle

  16. Inhibition of granulation tissue growth by histamine.

    PubMed

    Saeki, K; Yokoyama, J; Wake, K

    1975-06-01

    Granulomas were induced in rats by subcutaneous implantation of formalin-soaked filter-paper disks. Daily subcutaneous injection of histamine at doses of two times 0.05 mg/kg and above inhibited the growth of granulation tissue as measured by a marked decrease in the dry-defatted granuloma weight and of the hydroxyproline and hexosamine content. Histological observations of granulation tissue indicated that histamine inhibited the proliferation of fibroblasts and the formation of capillaries. Inhibitory effects were also observed with the histamine releaser, sinomenine, and the histaminase inhibitor, aminoguanidine. These histamine effects seem not to be mediated by glucocorticoid release, since an effective dose level of histamine produced no change in growth or thymus weight. Prednisolone was less potent than histamine in inhibiting Prednisolone was ineffective at the dose tested. Subcutaneous injection of the H2-receptor antagonist, burimamide, blocked these histamine effects and also of sinomeinine and aminoguanidine. The H1-receptor antagonist, mepyramine, did not block these histamine effects. Burimamide alone enhanced the growth of granuloma. These results indicate that granulation-tissue growth in inflammation is affected by the inhibitory effect of endogenous histamine acting through H2-receptors.

  17. Bacterial contact-dependent growth inhibition (CDI)

    PubMed Central

    Ruhe, Zachary C.; Low, David A.; Hayes, Christopher S.

    2013-01-01

    Bacteria cooperate to form multicellular communities and compete against one another for environmental resources. Here, we review recent advances in our understanding of bacterial competition mediated by contact-dependent growth inhibition (CDI) systems. Different CDI+ bacteria deploy a variety of toxins to inhibit neighboring cells and protect themselves from autoinhibition by producing specific immunity proteins. The genes encoding CDI toxin–immunity pairs appear to be exchanged between cdi loci and are often associated with other toxin-delivery systems in diverse bacteria. CDI also appears to facilitate cooperative behavior between kin, suggesting that these systems may have other roles beyond competition. PMID:23473845

  18. Hydroxyapatite growth inhibition by osteopontin hexapeptide sequences.

    PubMed

    Silverman, L D; Saadia, M; Ishal, J S; Tishbi, N; Leiderman, E; Kuyunov, I; Recca, B; Reitblat, C; Viswanathan, R

    2010-06-15

    The effects of three acidic hexapeptides on in vitro hydroxyapatite growth were characterized by pH-stat kinetic studies, adsorption isotherms, and molecular modeling. The three peptides, pSDEpSDE, SDESDE, and DDDDDD, are equal-length model compounds for the acidic sequences in osteopontin, a protein that inhibits mineral formation in both calcified and noncalcified tissues. Growth rates from 1.67 mM calcium and 1.00 mM phosphate solution were measured at pH 7.4 and 37 degrees C in 150 mM NaCl. pSDEpSDE was a strong growth inhibitor when preadsorbed onto hydroxyapatite (HA) seeds from > or = 0.67 mM solutions, concentrations where adsorption isotherms showed relatively complete surface coverage. The nonphosphorylated SDESDE control showed no growth inhibition. Although it adsorbed to almost the same extent as pSDEpSDE, it rapidly desorbed under the pH-stat growth conditions while pSDEpSDE did not. DDDDDD exhibited weak inhibition as its concentration was increased and similar adsorption/desorption behavior to pSDEpSDE. Molecular modeling yielded binding energy trends based on simple adsorption of peptides on the [100] surface that were consistent with observed inhibition, but not for the [001] surface. The relatively unfavorable binding energies for peptides on the [001] surface suggest that their absorption will be primarily on the [100] face. The kinetic and adsorption data are consistent with phosphorylation of osteopontin acting to control mineral formation.

  19. Inhibition of estrogen biosynthesis enhances lymphoma growth in mice.

    PubMed

    Talaber, Gergely; Yakimchuk, Konstantin; Guan, Jiyu; Inzunza, Jose; Okret, Sam

    2016-04-12

    Most lymphomas show higher incidence and poorer prognosis in males compared to females. However, the endocrine contribution to this gender difference is not entirely known. Here we show that castration accelerates lymphoma growth in C57BL6 male mice grafted with murine EG7 T cell lymphoma cells. However, the androgen receptor antagonist Bicalutamide did not affect lymphoma growth, suggesting no impact of androgen receptor signaling on lymphoma progression. In contrast, inhibition of androgen-to-estrogen conversion by the aromatase inhibitor (AI) Letrozole induced faster lymphoma growth in mice, suggesting that androgens impact lymphoma growth through its conversion to estrogens. This was supported by the inability of dihydrotestosterone, which is not converted to estrogens by aromatase, to influence lymphoma growth in castrated male mice. Lymphoma growth was also stimulated in immunocompromised mice grafted with human B cell lymphoma (Granta-519) and treated with either reversible or irreversible AIs, showing that the blockage of estrogen synthesis caused enhanced growth of both murine T and human B cell lymphomas and with different AIs. Additionally, AI-treated EG7 lymphomas showed accelerated growth not only in male but also in intact female mice. Altogether, our results demonstrate that aromatase inhibition accelerates lymphoma growth but not androgens per se, highlighting a protective role of estrogens in lymphoma pathogenesis. These results also raise concern that the use of AIs in women with breast cancer might enhance lymphoma progression.

  20. Inhibition of estrogen biosynthesis enhances lymphoma growth in mice

    PubMed Central

    Talaber, Gergely; Yakimchuk, Konstantin; Guan, Jiyu; Inzunza, Jose; Okret, Sam

    2016-01-01

    Most lymphomas show higher incidence and poorer prognosis in males compared to females. However, the endocrine contribution to this gender difference is not entirely known. Here we show that castration accelerates lymphoma growth in C57BL6 male mice grafted with murine EG7 T cell lymphoma cells. However, the androgen receptor antagonist Bicalutamide did not affect lymphoma growth, suggesting no impact of androgen receptor signaling on lymphoma progression. In contrast, inhibition of androgen-to-estrogen conversion by the aromatase inhibitor (AI) Letrozole induced faster lymphoma growth in mice, suggesting that androgens impact lymphoma growth through its conversion to estrogens. This was supported by the inability of dihydrotestosterone, which is not converted to estrogens by aromatase, to influence lymphoma growth in castrated male mice. Lymphoma growth was also stimulated in immunocompromised mice grafted with human B cell lymphoma (Granta-519) and treated with either reversible or irreversible AIs, showing that the blockage of estrogen synthesis caused enhanced growth of both murine T and human B cell lymphomas and with different AIs. Additionally, AI-treated EG7 lymphomas showed accelerated growth not only in male but also in intact female mice. Altogether, our results demonstrate that aromatase inhibition accelerates lymphoma growth but not androgens per se, highlighting a protective role of estrogens in lymphoma pathogenesis. These results also raise concern that the use of AIs in women with breast cancer might enhance lymphoma progression. PMID:26943574

  1. Fluoxetine regulates cell growth inhibition of interferon-α.

    PubMed

    Lin, Yu-Min; Yu, Bu-Chin; Chiu, Wen-Tai; Sun, Hung-Yu; Chien, Yu-Chieh; Su, Hui-Chen; Yen, Shu-Yang; Lai, Hsin-Wen; Bai, Chyi-Huey; Young, Kung-Chia; Tsao, Chiung-Wen

    2016-10-01

    Fluoxetine, a well-known anti-depression agent, may act as a chemosensitizer to assist and promote cancer therapy. However, how fluoxetine regulates cellular signaling to enhance cellular responses against tumor cell growth remains unclear. In the present study, addition of fluoxetine promoted growth inhibition of interferon-alpha (IFN-α) in human bladder carcinoma cells but not in normal uroepithelial cells through lessening the IFN-α-induced apoptosis but switching to cause G1 arrest, and maintaining the IFN-α-mediated reduction in G2/M phase. Activations and signal transducer and transactivator (STAT)-1 and peroxisome proliferator-activated receptor alpha (PPAR-α) were involved in this process. Chemical inhibitions of STAT-1 or PPAR-α partially rescued bladder carcinoma cells from IFN-α-mediated growth inhibition via blockades of G1 arrest, cyclin D1 reduction, p53 downregulation and p27 upregulation in the presence of fluoxetine. However, the functions of both proteins were not involved in the control of fluoxetine over apoptosis and maintained the declined G2/M phase of IFN-α. These results indicated that activation of PPAR-α and STAT-1 participated, at least in part, in growth inhibition of IFN-α in the presence of fluoxetine.

  2. Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans

    PubMed Central

    Vediyappan, Govindsamy; Dumontet, Vincent; Pelissier, Franck; d’Enfert, Christophe

    2013-01-01

    Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine. PMID:24040201

  3. Gymnemic acids inhibit hyphal growth and virulence in Candida albicans.

    PubMed

    Vediyappan, Govindsamy; Dumontet, Vincent; Pelissier, Franck; d'Enfert, Christophe

    2013-01-01

    Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine.

  4. Inhibition of green algae growth by corrole-based photosensitizers.

    PubMed

    Pohl, J; Saltsman, I; Mahammed, A; Gross, Z; Röder, B

    2015-02-01

    This study was performed to examine the potential of photodynamic inactivation for growth inhibition of green algae through generation of singlet oxygen. Two cationic and two anionic corroles were investigated according to their photoinhibitive effect on two strains of green algae using visible light for photoexcitation. The development of biomass over the experimental period of 18 days was followed using absorptive properties of the algae samples. The anionic photosensitizers showed no significant phototoxicity, whereas the cationic photosensitizers caused a drastic reduction of biomass on a short time scale and also displayed long-term inhibition of algae growth. In general, it was proven that photodynamic inactivation of green algae is possible. Concluding from the results of this study, cationic photosensitizers are favourable for this task, while anionic photosensitizers are not suited. Phototrophic biofilms are an important factor in biofouling and biodeterioration of building materials, causing great damage to historic and contemporary constructions. Growth inhibition of phototrophic organisms using photodynamic inactivation could pose an alternative to the use of biocides. To this end, successful application of this approach on green algae is a vital step in the development of suitable photosensitizers. © 2014 The Society for Applied Microbiology.

  5. Simulating cholinesterase inhibition in birds caused by dietary insecticide exposure

    USGS Publications Warehouse

    Corson, M.S.; Mora, M.A.; Grant, W.E.

    1998-01-01

    We describe a stochastic simulation model that simulates avian foraging in an agricultural landscape to evaluate factors affecting dietary insecticide exposure and to predict post-exposure cholinesterase (ChE) inhibition. To evaluate the model, we simulated published field studies and found that model predictions of insecticide decay and ChE inhibition reasonably approximated most observed results. Sensitivity analysis suggested that foraging location usually influenced ChE inhibition more than diet preferences or daily intake rate. Although organophosphorus insecticides usually caused greater inhibition than carbamate insecticides, insecticide toxicity appeared only moderately important. When we simulated impact of heavy insecticide applications during breeding seasons of 15 wild bird species, mean maximum ChE inhibition in most species exceeded 20% at some point. At this level of inhibition, birds may experience nausea and/or may exhibit minor behavioral changes. Simulated risk peaked in April-May and August-September and was lowest in July. ChE inhibition increased with proportion of vegetation in the diet. This model, and ones like it, may help predict insecticide exposure of and sublethal ChE inhibition in grassland animals, thereby reducing dependence of ecological risk assessments on field studies alone.

  6. Inhibition of growth and aflatoxin production in Aspergillus parasiticus by essential oils of selected plant materials.

    PubMed

    Tantaoui-Elaraki, A; Beraoud, L

    1994-01-01

    We studied the effect of 13 chemically different essential oils (EO) on the mycelial growth of and aflatoxin synthesis by Aspergillus parasiticus. Cinnamon, thyme, oregano, and cumin EO were able to stop mycelial growth at only 0.1% in the medium, while curcumin, ginger, lemon, and orange EO were unable to inhibit totally the growth even at 1% concentration. Coriander, black pepper, mugwort, bay, and rosemary EO caused the growth to stop at concentrations between 0.2 and 1%. The EO most active upon mycelial growth were also the most active against aflatoxinogenesis. However, aflatoxin synthesis was inhibited by all the EO at higher extent than the mycelial growth.

  7. Selective inhibition of Klebsiella aerogenes growth on pentoses by pentitols.

    PubMed Central

    Izumori, K; Yamanaka, K

    1978-01-01

    Selective inhibition of growth by pentitols was observed when Klebsiella aerogenes M-7 which could not utilize pentitols was grown on pentoses. D-Arabitol inhibited the growth on D-arabinose as a sole carbon source, but had no effect on the growth on L-arabinose, D-xylose, and D-ribose. Similarly, L-arabitol inhibited the growth on D-arabinose and L-arabinose, ribitol inhibited the growth on D-arabinose and L-arabinose, and xylitol inhibited the growth on D-xylose. From the following reasons, we postulated that the selective growth inhibition by pentitols was due to the competitive inhibition of pentose isomerase reaction by the cell by pentitols. (i) D-Arabinose transport activity was not inhibited by pentitols. (ii) Induction of D-arabinose and L-arabinose isomerases was not inhibited by D- and L-arabitol, respectively. (iii) The specificity of growth inhibition by pentitols was the same as that of competitive inhibition of pentose isomerases by pentitols. PMID:350845

  8. Inhibition of growth of Trichophyton tonsurans by Lactobacillus reuteri.

    PubMed

    Guo, J; Mauch, A; Galle, S; Murphy, P; Arendt, E K; Coffey, A

    2011-08-01

    The aims of this study were to identify antifungal lactic acid bacteria (LAB) and characterize their activity against the dermatophyte Trichophyton tonsurans. A total of 165 different LAB were isolated and initially screened for anti-Penicillium expansum activity. Five strains, which exhibited strong inhibitory activity, were then tested against the dermatophyte T. tonsurans DSM12285, where they also caused inhibition as observed by large fungal clearing on agar surface. The strongest inhibition was seen with Lactobacillus reuteri R2. When freeze-dried cell-free supernatant powder from this strain was incorporated in culture medium at concentrations >1%, growth of fungal colony was inhibited. Conidia germination was also inhibited under these conditions as determined by microscopy. The anti-T. tonsurans activity of Lact. reuteri R2 was not affected neither by heat treatment nor by proteolytic treatment using pronase E and proteinase K, indicating that the responsible agent(s) were nonproteinaceous in nature. Lactobacillus reuteri R2 was identified as having strong inhibitory activity against the dermatophyte T. tonsurans DSMZ12285. LAB are naturally associated with many foods and are well recognized for their biopreservative properties. The use of these and/or their products may well provide alternative safe approaches for the inhibition of dermatophytic fungi. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  9. Telmisartan inhibits human urological cancer cell growth through early apoptosis

    PubMed Central

    MATSUYAMA, MASAHIDE; FUNAO, KIYOAKI; KURATSUKURI, KATSUYUKI; TANAKA, TOMOAKI; KAWAHITO, YUTAKA; SANO, HAJIME; CHARGUI, JAMEL; TOURAINE, JEAN-LOUIS; YOSHIMURA, NORIO; YOSHIMURA, RIKIO

    2010-01-01

    Angiotensin II receptor blockers (ARBs) are widely used as hypertensive therapeutic agents. In addition, studies have provided evidence that ARBs have the potential to inhibit the growth of several types of cancer cells. It was reported that telmisartan (a type of ARB) has peroxisome proliferator-activated receptor (PPAR)-γ activation activity. We previously reported that the PPAR-γ ligand induces growth arrest in human urological cancer cells through apoptosis. In this study, we evaluated the effects of telmisartan and other ARBs on cell proliferation in renal cell carcinoma (RCC), bladder cancer (BC), prostate cancer (PC) and testicular cancer (TC) cell lines. The inhibitory effects of telmisartan and other ARBs (candesartan, valsartan, irbesartan and losartan) on the growth of the RCC, BC, PC and TC cell lines was investigated using an MTT assay. Flow cytometry and Hoechst staining were used to determine whether the ARBs induced apoptosis. Telmisartan caused marked growth inhibition in the urological cancer cells in a dose- and time-dependent manner. Urological cancer cells treated with 100 μM telmisartan underwent early apoptosis and DNA fragmentation. However, the other ARBs had no effect on cell proliferation in any of the urological cancer cell lines. Telmisartan may mediate potent anti-proliferative effects in urological cancer cells through PPAR-γ. Thus, telmisartan is a potent target for the prevention and treatment of human urological cancer. PMID:22993542

  10. Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

    PubMed Central

    Williams, Christopher S; Goldman, Angela P; Sheng, Hongmiao; Morrow, Jason D; DuBois, Raymond N

    1999-01-01

    Abstract Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID) sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice. PMID:10933052

  11. FNC efficiently inhibits mantle cell lymphoma growth.

    PubMed

    Zhang, Yan; Zhang, Rong; Ding, Xixi; Peng, Bangan; Wang, Ning; Ma, Fang; Peng, Youmei; Wang, Qingduan; Chang, Junbiao

    2017-01-01

    FNC, 2'-deoxy-2'-β-fluoro-4'-azidocytidine, is a novel cytidine analogue, that has shown strong antiproliferative activity in human lymphoma, lung adenocarcinoma and acute myeloid leukemia. In this study, we investigated the effects of FNC on mantle cell lymphoma (MCL) and the underlying mechanisms. In in vitro experiments, cell viability was detected by the CCK8 assay, and cell cycle progression and apoptosis were assessed by flow cytometry, and the expression of relative apoptosis proteins were detected by Western Blot. The in vivo antitumor effect of FNC was investigated in a SCID xenograft model. Finally, the mechanisms of action of FNC were assessed using a whole human genome expression profile chip. The data showed that FNC inhibited cell growth in a dose- and time-dependent manner, and FNC could induce apoptosis by the death recepter pathways in JeKo-1 cells and arrest the cell cycle in the G1/S or G2/M phase. Notably, FNC showed in vivo efficacy in mice bearing JeKo-1 xenograft tumors. Gene expression profile analysis revealed that the differentially expressed genes were mainly focused on the immune system process, cellular process and death. These findings implied that FNC may be a valuable therapeutic in mantle cell lymphoma and provided an experimental basis for the early clinical application of FNC.

  12. FNC efficiently inhibits mantle cell lymphoma growth

    PubMed Central

    Ding, Xixi; Peng, Bangan; Wang, Ning; Ma, Fang; Peng, Youmei; Wang, Qingduan; Chang, Junbiao

    2017-01-01

    FNC, 2'-deoxy-2'-β-fluoro-4'-azidocytidine, is a novel cytidine analogue, that has shown strong antiproliferative activity in human lymphoma, lung adenocarcinoma and acute myeloid leukemia. In this study, we investigated the effects of FNC on mantle cell lymphoma (MCL) and the underlying mechanisms. In in vitro experiments, cell viability was detected by the CCK8 assay, and cell cycle progression and apoptosis were assessed by flow cytometry, and the expression of relative apoptosis proteins were detected by Western Blot. The in vivo antitumor effect of FNC was investigated in a SCID xenograft model. Finally, the mechanisms of action of FNC were assessed using a whole human genome expression profile chip. The data showed that FNC inhibited cell growth in a dose- and time-dependent manner, and FNC could induce apoptosis by the death recepter pathways in JeKo-1 cells and arrest the cell cycle in the G1/S or G2/M phase. Notably, FNC showed in vivo efficacy in mice bearing JeKo-1 xenograft tumors. Gene expression profile analysis revealed that the differentially expressed genes were mainly focused on the immune system process, cellular process and death. These findings implied that FNC may be a valuable therapeutic in mantle cell lymphoma and provided an experimental basis for the early clinical application of FNC. PMID:28333959

  13. Conditioned medium from neural stem cells inhibits glioma cell growth.

    PubMed

    Li, Z; Zhong, Q; Liu, H; Liu, P; Wu, J; Ma, D; Chen, X; Yang, X

    2016-10-31

    Malignant glioma is one of the most common brain tumors in the central nervous system. Although the significant progress has been made in recent years, the mortality is still high and 5-year survival rate is still very low. One of the leading causes to the high mortality for glioma patients is metastasis and invasion. An efficient method to control the tumor metastasis is a promising way to treat the glioma. Previous reports indicated that neural stem cells (NSCs) were served as a delivery vector to the anti-glioma therapy. Here, we used the conditioned medium from rat NSCs (NSC-CM) to culture the human glioblastoma cell lines. We found that NSC-CM could inhibit the glioma cell growth, invasion and migration in vitro and attenuate the tumor growth in vivo. Furthermore, this anti-glioma effect was mediated by the inactivation of mitogen activated protein kinase (MAPK) pathway. Above all, this study provided the direct evidence to put forward a simple and efficient method in the inhibition of glioma cells/tumor growth, potentially advancing the anti-glioma therapy.

  14. Exogenous ethylene inhibits sprout growth in onion bulbs

    PubMed Central

    Bufler, Gebhard

    2009-01-01

    Background and Aims Exogenous ethylene has recently gained commercial interest as a sprouting inhibitor of onion bulbs. The role of ethylene in dormancy and sprouting of onions, however, is not known. Methods A cultivar (Allium cepa ‘Copra’) with a true period of dormancy was used. Dormant and sprouting states of onion bulbs were treated with supposedly saturating doses of ethylene or with the ethylene-action inhibitor 1-methylcyclopropene (1-MCP). Initial sprouting was determined during storage at 18 °C by monitoring leaf blade elongation in a specific size class of leaf sheaths. Changes in ATP content and sucrose synthase activity in the sprout leaves, indicators of the sprouting state, were determined. CO2 and ethylene production of onion bulbs during storage were recorded. Key results Exogenous ethylene suppressed sprout growth of both dormant and already sprouting onion bulbs by inhibiting leaf blade elongation. In contrast to this growth-inhibiting effect, ethylene stimulated CO2 production by the bulbs about 2-fold. The duration of dormancy was not significantly affected by exogenous ethylene. However, treatment of dormant bulbs with 1-MCP caused premature sprouting. Conclusions Exogenous ethylene proved to be a powerful inhibitor of sprout growth in onion bulbs. The dormancy breaking effect of 1-MCP indicates a regulatory role of endogenous ethylene in onion bulb dormancy. PMID:18940850

  15. Repression of PES1 expression inhibits growth of gastric cancer.

    PubMed

    Li, Jieping; Zhou, Xiaodong; Lan, Xiaopeng; Zeng, Guobin; Jiang, Xuping; Huang, Zongming

    2016-03-01

    Gastric cancer is one of the leading causes of cancer death worldwide. However, precise molecular mechanisms underlining its development are far from clear. We recently reported that PES1 promoted development of breast cancer and ovarian cancer as an oncogene. In this study, we reported that ablation of endogenous PES1 resulted in significant suppression of cell proliferation and growth and led to cell cycle arrest in G2 or G1 phase, respectively, in two gastric cancer cell lines (AGS and N87) in vitro. Meanwhile, silencing of PES1 obviously decreased expressions of cyclin D1, HIF-1α, and vascular endothelial growth factor (VEGF) expressions and increased p21WAF1 expression. Re-expression of PES1 in these two kinds of PES1 knockdown cells rescued these effects. In vivo, repression of endogenous PES1 expression suppressed gastric tumor growth in nude mice. In addition, 40.7 % (24/59) of gastric cancer tissues showed PES1 expression via immunohistochemical (IHC) staining. However, there were not any positive PES1 stainings in matched adjacent tissues. Our results demonstrated that repression of PES1 changed expressions of some cell proliferation- and angiogenesis-related genes and inhibited gastric cancer growth, and PES1 expression increased in gastric cancer tissues. These results suggest that PES1 may play an important role in development of gastric cancer. PES1 may be a potential target for gastric cancer therapy.

  16. Kinetic model of particle-inhibited grain growth

    NASA Astrophysics Data System (ADS)

    Thompson, Gary Scott

    The effects of second phase particles on matrix grain growth kinetics were investigated using Al2O3-SiC as a model system. In particular, the validity of the conclusion drawn from a previous kinetic analysis that the kinetics of particle-inhibited grain growth in Al2 O3-SiC samples with an intermediate volume fraction of second phase could be well quantified by a modified-Zener model was investigated. A critical analysis of assumptions made during the previous kinetic analysis revealed oversimplifications which affect the validity of the conclusion. Specifically, the degree of interaction between particles and grain boundaries was assumed to be independent of the mean second phase particle size and size distribution. In contrast, current measurements indicate that the degree of interaction in Al2O3-SiC is dependent on these parameters. An improved kinetic model for particle-inhibited grain growth in Al 2O3-SiC was developed using a modified-Zener approach. The comparison of model predictions with experimental grain growth data indicated that significant discrepancies (as much as 4--5 orders of magnitude) existed. Based on this, it was concluded that particles had a much more significant effect on grain growth kinetics than that caused by a simple reduction of the boundary driving force due to the removal of boundary area. Consequently, it was also concluded that the conclusion drawn from the earlier kinetic analysis regarding the validity of a modified-Zener model was incorrect. Discrepancies between model and experiment were found to be the result of a significant decrease in experimental growth rate constant not predicted by the model. Possible physical mechanisms for such a decrease were investigated. The investigation of a small amount of SiO2 on grain growth in Al2O3 indicated that the decrease was not the result of a decrease in grain boundary mobility due to impurity contamination by particles. By process of elimination and based on previous observations

  17. Alpha1-antitrypsin inhibits angiogenesis and tumor growth.

    PubMed

    Huang, Hanhua; Campbell, Steven C; Nelius, Thomas; Bedford, Dhugal F; Veliceasa, Dorina; Bouck, Noel P; Volpert, Olga V

    2004-12-20

    Disturbances of the ratio between angiogenic inducers and inhibitors in tumor microenvironment are the driving force behind angiogenic switch critical for tumor progression. Angiogenic inhibitors may vary depending on organismal age and the tissue of origin. We showed that alpha(1)-antitrypsin (AAT), a serine protease inhibitor (serpin) is an inhibitor of angiogenesis, which induced apoptosis and inhibited chemotaxis of endothelial cells. S- and Z-type mutations that cause abnormal folding and defective serpin activity abrogated AAT antiangiogenic activity. Removal of the C-terminal reactive site loop had no effect on its angiostatic activity. Both native AAT and AAT truncated on C-terminus (AATDelta) inhibited neovascularization in the rat cornea and delayed the growth of subcutaneous tumors in mice. Treatment with native AAT and truncated AATDelta, but not control vehicle reduced tumor microvessel density, while increasing apoptosis within tumor endothelium. Comparative analysis of the human tumors and normal tissues of origin showed correlation between reduced local alpha(1)-antitrypsin expression and more aggressive tumor growth.

  18. Bee venom inhibits growth of human cervical tumors in mice

    PubMed Central

    Kim, Tae Myoung; Jung, Yu Yeon; Park, Mi Hee; Oh, Sang Hyun; Yun, Hye Seok; Jun, Hyung Ok; Yoo, Hwan Soo; Han, Sang-Bae; Lee, Ung Soo; Yoon, Joo Hee; Song, Min Jong; Hong, Jin Tae

    2015-01-01

    We studied whether bee venom (BV) inhibits cervical tumor growth through enhancement of death receptor (DR) expressions and inactivation of nuclear factor kappa B (NF-κB) in mice. In vivo study showed that BV (1 mg/kg) inhibited tumor growth. Similar inhibitory effects of BV on cancer growth in primary human cervical cancer cells were also found. BV (1–5 μg/ml) also inhibited the growth of cancer cells, Ca Ski and C33Aby the induction of apoptotic cell death in a dose dependent manner. Agreed with cancer cell growth inhibition, expression of death receptors; FAS, DR3 and DR6, and DR downstream pro-apoptotic proteins including caspase-3 and Bax was concomitantly increased, but the NF-κB activity and the expression of Bcl-2 were inhibited by treatment with BV in tumor mice, human cancer cell and human tumor samples as well as cultured cancer cells. In addition, deletion of FAS, DR3 and DR6 by small interfering RNA significantly reversed BV-induced cell growth inhibitory effects as well as NF-κB inactivation. These results suggest that BV inhibits cervical tumor growth through enhancement of FAS, DR3 and DR6 expression via inhibition of NF-κB pathway. PMID:25730901

  19. A chemical pollen suppressant inhibits auxin-induced growth in maize coleoptile sections

    SciTech Connect

    Vesper, M.J. ); Cross, J.W. )

    1990-05-01

    Chemical inhibitors of pollen development having a phenylcinnoline carboxylate structure were found to inhibit IAA- and 1-NAA-induced growth in maize coleoptile sections. The inhibitor (100 {mu}M) used in these experiments caused approx. 35% reduction in auxin-induced growth over the auxin concentration range of 0.3 to 100 {mu}M. Growth inhibition was noted as a lengthening of the latent period and a decrease in the rate of an auxin-induced growth response. An acid growth response to pH 5 buffer in abraded sections was not impaired. The velocity of basipetal transport of ({sup 3}H)IAA through the coleoptile sections also was not inhibited by the compound, nor was uptake of ({sup 3}H)IAA. Similarly, the inhibitor does not appear to alter auxin-induced H{sup +} secretion. We suggest that the agent targets some other process necessary for auxin-dependent growth.

  20. Proteasomal inhibition causes loss of nigral tyrosine hydroxylase neurons.

    PubMed

    Schapira, Anthony H V; Cleeter, Michael W J; Muddle, John R; Workman, Jane M; Cooper, J Mark; King, Rosalind H M

    2006-08-01

    Dysfunction of the ubiquitin-proteasomal system (UPS) has been implicated in the pathogenesis of Parkinson's disease. The systemic administration of UPS inhibitors has been reported to induce nigrostriatal cell death and model Parkinson's disease pathology in rodents. We administered a synthetic, specific UPS inhibitor (PSI) subcutaneously to rats and quantified substantia nigral tyrosine hydroxylase-positive dopaminergic neurons by stereology. PSI caused a 15% decrease in UPS activity at 2 weeks and a 42% reduction in substantia nigra pars compacta tyrosine hydroxylase-positive neurons at 8 weeks. Systemic inhibition of the UPS warrants further evaluation as a means to model Parkinson's disease.

  1. Hydrogen peroxide inhibits the growth of cyanobacteria.

    PubMed

    Samuilov, V D; Bezryadnov, D V; Gusev, M V; Kitashov, A V; Fedorenko, T A

    1999-01-01

    H2O2 at concentrations of 10(-5)-10(-4) M suppresses phototrophic growth of Anacystis nidulans and Anabaena variabilis in dialysis culture. The growth of the cyanobacteria resumed after a long adaptation period. In batch cultures, the growth of A. nidulans and A. variabilis was suppressed after one-time addition of 10(-2)and 10(-3)-10(-2) M H2O2, respectively. Inducing intracellular H2O2 formation by adding methylviologen, vitamin K3, or phenazine methosulfate suppresses the growth of both cyanobacteria. The catalase inhibitor salicylic acid suppresses the growth of A. nidulans and A. variabilis at a concentration of 5.10(-3) M. The data suggest an inhibitory effect of H2O2 on the growth of the cyanobacteria. H2O2 is unlikely to serve as an electron donor during photosynthesis.

  2. Calcite crystal growth rate inhibition by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  3. Schlafen-1 causes a cell cycle arrest by inhibiting induction of cyclin D1.

    PubMed

    Brady, Gareth; Boggan, Louise; Bowie, Andrew; O'Neill, Luke A J

    2005-09-02

    Schlafen-1 (Slfn-1), the prototypic member of the Schlafen family of proteins, was described as an inducer of growth arrest in T-lymphocytes and causes a cell cycle arrest in NIH3T3 fibroblasts prior to the G1/S transition. How Slfn-1 exerts its effects on the cell cycle is not currently known. We report that synchronized murine fibroblasts expressing Slfn-1 do not exit G1 when stimulated with fetal calf serum, platelet-derived growth factor BB (PDGF-BB) or epidermal growth factor (EGF). The induction of cyclin D1 by these stimuli was blocked in the presence of Slfn-1 as were all downstream cell cycle processes. Overexpression of cyclin D1 in growth-arrested, Slfn-1-expressing cells induced an increase in cell growth consistent with this protein being the biological target of Slfn-1. Activation of the mitogen-activated protein kinase pathway by EGF or phorbol 12-myristate 13-acetate was unaffected by Slfn-1 expression. PDGF signaling was, however, almost completely blocked. This was due to a lack of PDGF receptor expression in Slfn-1-expressing cells consistent with Slfn-1 blocking the cell cycle in G1 where PDGF receptor expression is normally down-regulated. Finally, overexpression of Slfn-1 inhibited the activation of the cyclin D1 promoter. Slfn-1 therefore causes a cell cycle arrest during G1 by inhibiting induction of cyclin D1 by mitogens.

  4. College-Student Personal-Growth and Attributions of Cause

    ERIC Educational Resources Information Center

    Anderson, W. P., Jr.; Lopez-Baez, Sandra I.

    2012-01-01

    Little is known about levels of personal growth attributed by students to typical college life experiences. This paper documents two studies of student self-reported and posttraumatic growth and compares growth levels across populations. Both studies measure student attributions of cause to academic and non-academic experiences, respectively. It…

  5. Di(2-ethylhexyl) phthalate inhibits antral follicle growth, induces atresia, and inhibits steroid hormone production in cultured mouse antral follicles

    SciTech Connect

    Hannon, Patrick R. Brannick, Katherine E. Wang, Wei Gupta, Rupesh K. Flaws, Jodi A.

    2015-04-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental toxicant found in consumer products that causes ovarian toxicity. Antral follicles are the functional ovarian units and must undergo growth, survival from atresia, and proper regulation of steroidogenesis to ovulate and produce hormones. Previous studies have determined that DEHP inhibits antral follicle growth and decreases estradiol levels in vitro; however, the mechanism by which DEHP elicits these effects is unknown. The present study tested the hypothesis that DEHP directly alters regulators of the cell cycle, apoptosis, and steroidogenesis to inhibit antral follicle functionality. Antral follicles from adult CD-1 mice were cultured with vehicle control or DEHP (1–100 μg/ml) for 24–96 h to establish the temporal effects of DEHP on the follicle. Following 24–96 h of culture, antral follicles were subjected to gene expression analysis, and media were subjected to measurements of hormone levels. DEHP increased the mRNA levels of cyclin D2, cyclin dependent kinase 4, cyclin E1, cyclin A2, and cyclin B1 and decreased the levels of cyclin-dependent kinase inhibitor 1A prior to growth inhibition. Additionally, DEHP increased the mRNA levels of BCL2-associated agonist of cell death, BCL2-associated X protein, BCL2-related ovarian killer protein, B-cell leukemia/lymphoma 2, and Bcl2-like 10, leading to an increase in atresia. Further, DEHP decreased the levels of progesterone, androstenedione, and testosterone prior to the decrease in estradiol levels, with decreased mRNA levels of side-chain cleavage, 17α-hydroxylase-17,20-desmolase, 17β-hydroxysteroid dehydrogenase, and aromatase. Collectively, DEHP directly alters antral follicle functionality by inhibiting growth, inducing atresia, and inhibiting steroidogenesis. - Highlights: • DEHP inhibits antral follicle growth by dysregulating cell cycle regulators. • DEHP induces antral follicle atresia by dysregulating apoptosis regulators. • DEHP

  6. Two genetically separable phases of growth inhibition induced by blue light in Arabidopsis seedlings

    NASA Technical Reports Server (NTRS)

    Parks, B. M.; Cho, M. H.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

    1998-01-01

    High fluence-rate blue light (BL) rapidly inhibits hypocotyl growth in Arabidopsis, as in other species, after a lag time of 30 s. This growth inhibition is always preceded by the activation of anion channels. The membrane depolarization that results from the activation of anion channels by BL was only 30% of the wild-type magnitude in hy4, a mutant lacking the HY4 BL receptor. High-resolution measurements of growth made with a computer-linked displacement transducer or digitized images revealed that BL caused a rapid inhibition of growth in wild-type and hy4 seedlings. This inhibition persisted in wild-type seedlings during more than 40 h of continuous BL. By contrast, hy4 escaped from the initial inhibition after approximately 1 h of BL and grew faster than wild type for approximately 30 h. Wild-type seedlings treated with 5-nitro-2-(3-phenylpropylamino)-benzoic acid, a potent blocker of the BL-activated anion channel, displayed rapid growth inhibition, but, similar to hy4, these seedlings escaped from inhibition after approximately 1 h of BL and phenocopied the mutant for at least 2.5 h. The effects of 5-nitro-2-(3-phenylpropylamino)-benzoic acid and the HY4 mutation were not additive. Taken together, the results indicate that BL acts through HY4 to activate anion channels at the plasma membrane, causing growth inhibition that begins after approximately 1 h. Neither HY4 nor anion channels appear to participate greatly in the initial phase of inhibition.

  7. Human milk oligosaccharides inhibit growth of group B Streptococcus.

    PubMed

    Lin, Ann E; Autran, Chloe A; Szyszka, Alexandra; Escajadillo, Tamara; Huang, Mia; Godula, Kamil; Prudden, Anthony R; Boons, Geert-Jan; Lewis, Amanda L; Doran, Kelly S; Nizet, Victor; Bode, Lars

    2017-07-07

    Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of invasive bacterial infections in newborns, typically acquired vertically during childbirth secondary to maternal vaginal colonization. Human milk oligosaccharides (HMOs) have important nutritional and biological activities that guide the development of the immune system of the infant and shape the composition of normal gut microbiota. In this manner, HMOs help protect against pathogen colonization and reduce the risk of infection. In the course of our studies of HMO-microbial interactions, we unexpectedly uncovered a novel HMO property to directly inhibit the growth of GBS independent of host immunity. By separating different HMO fractions through multidimensional chromatography, we found the bacteriostatic activity to be confined to specific non-sialylated HMOs and synergistic with a number of conventional antibiotic agents. Phenotypic screening of a GBS transposon insertion library identified a mutation within a GBS-specific gene encoding a putative glycosyltransferase that confers resistance to HMOs, suggesting that HMOs may function as an alternative substrate to modify a GBS component in a manner that impairs growth kinetics. Our study uncovers a unique antibacterial role for HMOs against a leading neonatal pathogen and expands the potential therapeutic utility of these versatile molecules. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Further evidence that naphthoquinone inhibits Toxoplasma gondii growth in vitro.

    PubMed

    da Silva, Luciana Lemos Rangel; Portes, Juliana de Araujo; de Araújo, Marlon Heggdorne; Silva, Jéssica Lays Sant'ana; Rennó, Magdalena Nascimento; Netto, Chaquip Daher; da Silva, Alcides José Monteiro; Costa, Paulo Roberto Ribeiro; De Souza, Wanderley; Seabra, Sergio Henrique; DaMatta, Renato Augusto

    2015-12-01

    Toxoplasmosis is a widely disseminated disease caused by Toxoplasma gondii, an intracellular protozoan parasite. Standard treatment causes many side effects, such as depletion of bone marrow cells, skin rashes and gastrointestinal implications. Therefore, it is necessary to find chemotherapeutic alternatives for the treatment of this disease. It was shown that a naphthoquinone derivative compound is active against T. gondii, RH strain, with an IC50 around 2.5 μM. Here, three different naphthoquinone derivative compounds with activity against leukemia cells and breast carcinoma cell were tested against T. gondii (RH strain) infected LLC-MK2 cell line. All the compounds were able to inhibit parasite growth in vitro, but one of them showed an IC50 activity below 1 μM after 48 h of treatment. The compounds showed low toxicity to the host cell. In addition, these compounds were able to induce tachyzoite-bradyzoite conversion confirmed by morphological changes, Dolichus biflorus lectin cyst wall labeling and characterization of amylopectin granules in the parasites by electron microscopy analysis using the Thierry technique. Furthermore, the compounds induced alterations on the ultrastructure of the parasite. Taken together, our results point to the naphthoquinone derivative (LQB 151) as a potential compound for the development of new drugs for the treatment of toxoplasmosis.

  9. Protein kinase C activators inhibit capillary endothelial cell growth

    SciTech Connect

    Doctrow, S.R.

    1986-05-01

    Phorbol 12,13-dibutyrate (PDBu) binds specifically to bovine capillary endothelial (BCE) cells (K/sub d/ = 8nM) and inhibits the proliferation (K/sub 50/ = 6 +/- 4 nM). Under similar conditions, PDBu does not inhibit the growth of bovine aortic endothelial or smooth muscle cells. PDBu markedly attenuates the response of BCE cells to purified human hepatoma-derived growth factor which, in the absence of PDBu, stimulates BCE cell growth by about 3-fold. Several observations suggest that the inhibition of BCE cell growth by PDBu is mediated by protein kinase C: (1) different phorbol compounds inhibit BCE cell growth according to the relative potencies as protein kinase C activators (12-tetradecanoylphorbol 13-acetate > PDBu >> phorbol 12,13-diacetate >>>..beta..-phorbol; ..cap alpha..-phorbol 12,13-didecanoate). (2) Specific binding of PDBu to BCE cells is displaced by sn-1,2-dioctanoylglycerol (diC/sub 8/), a protein kinase C activator and an analog of the putative second messenger activating this kinase in vivo. The weak protein kinase C activator, sn-1,2-dibutyrylglycerol, does not affect PDBu binding. (3) A cytosolic extract from BCE cells contains a Ca/sup 2 +//phosphatidylserine-dependent kinase that is activated by diC/sub 8/ and PDBu, but not by ..beta..-phorbol. These results support a role for protein kinase C in suppressing capillary endothelial cell growth and may therefore have implications in the intracellular regulation of angiogenesis.

  10. Spectroscopic analysis of urinary calculi and inhibition of their growth

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Durrer, William; Govani, Jayesh; Reza, Layra; Pinales, Luis

    2009-10-01

    We present here a study of kidney stone formation and growth inhibition based on a traditional medicine approach with Aquatica Lour (RAL) herbal extracts. Kidney stone material systems were synthesized in vitro using a simplified single diffusion gel growth technique. With the objective of revealing the mechanism of inhibition of calculi formation by RAL extracts, samples prepared without the presence of extract, and with the presence of extract, were analyzed using Raman, photoluminescence, and XPS. The unexpected presence of Zn revealed by XPS in a sample prepared with RAL provides an explanation for the inhibition process, and also explains the dramatic reflectance of incident light observed in attempts to obtain infrared transmission data. Raman data are consistent with the binding of the inhibitor to the oxygen of the kidney stone. Photoluminescence data corroborate with the other results to provide additional evidence of Zn-related inhibition.

  11. Characterization of growth inhibition of oral bacteria by sophorolipid using a microplate-format assay

    USDA-ARS?s Scientific Manuscript database

    Sophorolipid (SL) is a class of glycolipid biosurfactant produced by yeast and has potent antimicrobial activity against many microorganisms. In this paper, a microplate-based method was developed to characterize the growth inhibition by SL on five representative species of caries-causing oral bact...

  12. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth.

    PubMed

    Ahmad, Zulfiqar; Laughlin, Thomas F; Kady, Ismail O

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase.

  13. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth

    PubMed Central

    Ahmad, Zulfiqar; Laughlin, Thomas F.; Kady, Ismail O.

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase. PMID:25996607

  14. UV-B Inhibits Leaf Growth through Changes in Growth Regulating Factors and Gibberellin Levels1[OPEN

    PubMed Central

    Fina, Julieta; AbdElgawad, Hamada; Prinsen, Els

    2017-01-01

    Ultraviolet-B (UV-B) radiation affects leaf growth in a wide range of species. In this work, we demonstrate that UV-B levels present in solar radiation inhibit maize (Zea mays) leaf growth without causing any other visible stress symptoms, including the accumulation of DNA damage. We conducted kinematic analyses of cell division and expansion to understand the impact of UV-B radiation on these cellular processes. Our results demonstrate that the decrease in leaf growth in UV-B-irradiated leaves is a consequence of a reduction in cell production and a shortened growth zone (GZ). To determine the molecular pathways involved in UV-B inhibition of leaf growth, we performed RNA sequencing on isolated GZ tissues of control and UV-B-exposed plants. Our results show a link between the observed leaf growth inhibition and the expression of specific cell cycle and developmental genes, including growth-regulating factors (GRFs) and transcripts for proteins participating in different hormone pathways. Interestingly, the decrease in the GZ size correlates with a decrease in the concentration of GA19, the immediate precursor of the active gibberellin, GA1, by UV-B in this zone, which is regulated, at least in part, by the expression of GRF1 and possibly other transcription factors of the GRF family. PMID:28400494

  15. Ponicidin Inhibits Monocytic Leukemia Cell Growth by Induction of Apoptosis

    PubMed Central

    Liu, Jia-Jun; Zhang, Yong; Guang, Wei-Bin; Yang, Hong-Zhi; Lin, Dong-Jun; Xiao, Ruo-Zhi

    2008-01-01

    In this study two monocytic leukemia cell lines, U937 and THP-1 cells, were used to investigate the anti-proliferation effects caused by ponicidin. Cell viability was measured by an MTT assay. Cell apoptosis was assessed by flow cytometry as well as DNA fragmentation analysis. Cell morphology was observed using an inverted microscope and Hoechst 33258 staining. RT-PCR and Western blot analysis were used to detect survivin as well as Bax and Bcl-2 expressions after the cells were treated with different concentrations of ponicidin. The results revealed that ponicidin could inhibit the growth of U937 and THP-1 cells significantly by induction of apoptosis. The suppression was in both time- and dose-dependent manner. Marked morphological changes of cell apoptosis were observed clearly after the cells were treated with ponicidin for 48∼72 h. RT-PCR and Western blot analysis demonstrated that both survivin and Bcl-2 expressions were down-regulated remarkably while Bax expression remained constant before and after apoptosis occurred. We therefore conclude that ponicidin has significant anti-proliferation effects by inducing apoptosis on leukemia cells in vitro, downregulation of survivin as well as Bcl-2 expressions may be the important apoptosis inducing mechanisms. The results suggest that ponicidin may serve as potential therapeutic agent for leukemia. PMID:19330074

  16. Growth Inhibition of Caenorhabditis elegans and Panagrellus redivivus by Selected Mammalian and Insect Hormones

    PubMed Central

    Dropkin, V. H.; Lower, W. R.; Acedo, J.

    1971-01-01

    Caenorhabditis elegans and Panagrellus redivivus were cultured in axenic medium in microwells. The addition of selected steroids and terpenoids to the medium caused quantitative inhibition of numbers of offspring produced per well. Three out of 14 vertebrate sex hormones and analogs, and seven out of 10 insect juvenile hormones and analogs inhibited growth at 25 or 50 micrograms per ml. In addition, two insecticide synergists which mimic juvenile hormones, propyl 2-propynyl phenyl phosphonate and piperonyl butoxide, inhibited growth at 7 μg/ml. Total lipids from Panagrellus and from Nematospiroides dubius were inhibitory. Separation by silicic acid column chromatography yielded active and inactive portions. We concluded that the inhibition observed was non-specific. PMID:19322390

  17. Inhibition of breast cancer growth and metastasis by a biomimetic peptide.

    PubMed

    Lee, Esak; Lee, Seung Jae; Koskimaki, Jacob E; Han, Zheyi; Pandey, Niranjan B; Popel, Aleksander S

    2014-11-20

    Metastasis is the main cause of mortality in cancer patients. Though there are many anti-cancer drugs targeting primary tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression, particularly, lymphangiogenesis is pivotal for metastasis in breast cancer. Here we report that a novel collagen IV derived biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis. The peptide inhibits blood and lymphatic endothelial cell viability, migration, adhesion, and tube formation by targeting IGF1R and Met signals. The peptide blocks MDA-MB-231 tumor growth by inhibiting tumor angiogenesis in vivo. Moreover, the peptide inhibits lymphangiogenesis in primary tumors. MDA-MB-231 tumor conditioned media (TCM) was employed to accelerate spontaneous metastasis in tumor xenografts, and the anti-metastatic activity of the peptide was tested in this model. The peptide prevents metastasis to the lungs and lymph nodes by inhibiting TCM-induced lymphangiogenesis and angiogenesis in the pre-metastatic organs. In summary, a novel biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis in the pre-metastatic organs as well as primary tumors.

  18. Inhibition of breast cancer growth and metastasis by a biomimetic peptide

    PubMed Central

    Lee, Esak; Lee, Seung Jae; Koskimaki, Jacob E.; Han, Zheyi; Pandey, Niranjan B.; Popel, Aleksander S.

    2014-01-01

    Metastasis is the main cause of mortality in cancer patients. Though there are many anti-cancer drugs targeting primary tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression, particularly, lymphangiogenesis is pivotal for metastasis in breast cancer. Here we report that a novel collagen IV derived biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis. The peptide inhibits blood and lymphatic endothelial cell viability, migration, adhesion, and tube formation by targeting IGF1R and Met signals. The peptide blocks MDA-MB-231 tumor growth by inhibiting tumor angiogenesis in vivo. Moreover, the peptide inhibits lymphangiogenesis in primary tumors. MDA-MB-231 tumor conditioned media (TCM) was employed to accelerate spontaneous metastasis in tumor xenografts, and the anti-metastatic activity of the peptide was tested in this model. The peptide prevents metastasis to the lungs and lymph nodes by inhibiting TCM-induced lymphangiogenesis and angiogenesis in the pre-metastatic organs. In summary, a novel biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis in the pre-metastatic organs as well as primary tumors. PMID:25409905

  19. The thioamides methimazole and thiourea inhibit growth of M. avium Subspecies paratuberculosis in culture.

    PubMed

    Greenstein, Robert J; Su, Liya; Brown, Sheldon T

    2010-06-14

    Thyrotoxicosis is conceptualized as an "autoimmune" disease with no accepted infectious etiology. There are increasingly compelling data that another "autoimmune" affliction, Crohn disease, may be caused by Mycobacterium avium subspecies paratuberculosis (MAP). Like M. tb, MAP is systemic. We hypothesized that some cases of thyrotoxicosis may be initiated by a MAP infection. Because other thioamides treat tuberculosis, leprosy and M. avium complex, we hypothesized that a mode of action of some thioamide anti-thyrotoxicosis medications may include MAP growth inhibition. The effect of the thioamides, thiourea, methimazole and 6-propo-2-thiouracil (6-PTU) were studied in radiometric Bactec culture, on ten strains of three mycobacterial species (six of MAP, two of M. avium and two of M. tb. complex). Data are presented as "cumulative growth index," (cGI) or "percent decrease in cumulative GI" (%-DeltacGI). Methimazole was the most effective thioamide at inhibiting MAP growth. At 128microg/ml: MAP UCF-4; 65%-DeltacGI & MAP ATCC 19698; 90%-DeltacGI. Thiourea inhibited MAP "Ben" maximally; 70%-DeltacGI. Neither methimazole nor thiourea inhibited M. avium or M. tb. at the doses tested. 6-PTU has no inhibition on any strain studied, although a structurally analogous control, 5-PTU, was the most inhibitory thioamide tested. We show inhibition of MAP growth by the thioamides, thiourea and methimazole in culture. These data are compatible with the hypothesis that these thioamides may have anti-prokaryotic in addition to their well-established eukaryotic actions in thyrotoxic individuals.

  20. [Inhibition of growth of microscopic fungi with organic acids].

    PubMed

    Conková, E; Para, L; Kocisová, A

    1993-01-01

    Fungicidal effects of five selected organic acids (lactic, acetic, formic, oxalic, and propionic) in concentrations 3, 5, 10, 20 and 50 ml/l on nine selected species of moulds were tested. Lactic and oxalic acids did not prove the satisfactory fungicidal activity in any of the chosen concentrations. The antifungal effect of the other three acids, manifested by the growth inhibition of the tested moulds is shown in Tab. I and it can be expressed by sequence: propionic acid, formic acid, and acetic acid. These acids also had effects only in concentrations 20 ml/l and 50 ml/l. Propionic acid in concentration 20 ml/l inhibited the growth of five moulds (Penicillium glabrum, Aspergillus niger, Fusarium moniliforme, Aspergillus fumigatus, Cladosporium sphaerospermum). In testing of concentration 50 ml/l, the lower fungicidal ability was ascertained only in growth suppression of Aspergillus flavus. The fungicidal activity of formic acid was registered in concentration 20 ml/l in two cases and in concentration 50 ml/l in six cases. Acetic acid inhibited the growth in concentration 50 ml/l only in two cases. Tab. II shows the percentual evaluation of propionic acid and formic acid with regard to their inhibition abilities. The fungicidal efficiency of propionic acid resulting from the experiment is 88.9%.

  1. Plasmodium falciparum Choline Kinase Inhibition Leads to a Major Decrease in Phosphatidylethanolamine Causing Parasite Death

    PubMed Central

    Serrán-Aguilera, Lucía; Denton, Helen; Rubio-Ruiz, Belén; López-Gutiérrez, Borja; Entrena, Antonio; Izquierdo, Luis; Smith, Terry K.; Conejo-García, Ana; Hurtado-Guerrero, Ramon

    2016-01-01

    Malaria is a life-threatening disease caused by different species of the protozoan parasite Plasmodium, with P. falciparum being the deadliest. Increasing parasitic resistance to existing antimalarials makes the necessity of novel avenues to treat this disease an urgent priority. The enzymes responsible for the synthesis of phosphatidylcholine and phosphatidylethanolamine are attractive drug targets to treat malaria as their selective inhibition leads to an arrest of the parasite’s growth and cures malaria in a mouse model. We present here a detailed study that reveals a mode of action for two P. falciparum choline kinase inhibitors both in vitro and in vivo. The compounds present distinct binding modes to the choline/ethanolamine-binding site of P. falciparum choline kinase, reflecting different types of inhibition. Strikingly, these compounds primarily inhibit the ethanolamine kinase activity of the P. falciparum choline kinase, leading to a severe decrease in the phosphatidylethanolamine levels within P. falciparum, which explains the resulting growth phenotype and the parasites death. These studies provide an understanding of the mode of action, and act as a springboard for continued antimalarial development efforts selectively targeting P. falciparum choline kinase. PMID:27616047

  2. Cell growth inhibition by sequence-specific RNA minihelices.

    PubMed

    Hipps, D; Schimmel, P

    1995-08-15

    RNA minihelices which reconstruct the 12 base pair acceptor-T psi C domains of transfer RNAs interact with their cognate tRNA synthetases. These substrates lack the anticodons of the genetic code and, therefore, cannot participate in steps of protein synthesis subsequent to aminoacylation. We report here that expression in Escherichia coli of either of two minihelices, each specific for a different amino acid, inhibited cell growth. Inhibition appears to be due to direct competition between the minihelix and its related tRNA for binding to their common synthetase. This competition, in turn, sharply lowers the pool of the specific charged tRNA for protein synthesis. Inhibition is relieved by single nucleotide changes which disrupt the minihelix-synthetase interaction. The results suggest that sequence-specific RNA minihelix substrates bind to cognate synthetases in vivo and can, in principle, act as cell growth regulators. Naturally occurring non-tRNA substrates for aminoacylation may serve a similar purpose.

  3. Troglitazone inhibits vascular smooth muscle cell growth and intimal hyperplasia.

    PubMed Central

    Law, R E; Meehan, W P; Xi, X P; Graf, K; Wuthrich, D A; Coats, W; Faxon, D; Hsueh, W A

    1996-01-01

    Vascular smooth muscle cell (VSMC) proliferation and migration are responses to arterial injury that are highly important to the processes of restenosis and atherosclerosis. In the arterial balloon injury model in the rat, platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) are induced in the vessel wall and regulate these VSMC activities. Novel insulin sensitizing agents, thiazolidinediones, have been demonstrated to inhibit insulin and epidermal growth factor-induced growth of VSMCs. We hypothesized that these agents might also inhibit the effect of PDGF and bFGF on cultured VSMCs and intimal hyperplasia in vivo. Troglitazone (1 microM), a member of the thiazolidinedione class, produced a near complete inhibition of both bFGF-induced DNA synthesis as measured by bromodeoxyuridine incorporation (6.5+/-3.9 vs. 17.6+/-4.3% cells labeled, P < 0.05) and c-fos induction. This effect was associated with an inhibition (by 73+/-4%, P < 0.01) by troglitazone of the transactivation of the serum response element, which regulates c-fos expression. Inhibition of c-fos induction by troglitazone appeared to occur via a blockade of the MAP kinase pathway at a point downstream of MAP kinase activation by MAP kinase kinase. At this dose, troglitazone also inhibited PDGF-BB-directed migration of VSMC (by 70+/-6%, P < 0.01). These in vitro effects were operative in vivo. Quantitative image analysis revealed that troglitazone-treated rats had 62% (P < 0.001) less neointima/media area ratio 14 d after balloon injury of the aorta compared with injured rats that received no troglitazone. These results suggest troglitazone is a potent inhibitor of VSMC proliferation and migration and, thus, may be a useful agent to prevent restenosis and possibly atherosclerosis. PMID:8878442

  4. Short stature caused by a natural growth hormone antagonist.

    PubMed

    Chihara, K; Takahashi, Y; Kaji, H; Goji, K; Okimura, Y; Abe, H

    1998-01-01

    Severe short stature in a male child due to a single mutation in the GH-1 gene was first reported in 1996 by Takahashi et al. [N Engl J Med 1996;334:432-436]. This missense mutation was predicted to convert codon 77 from arginine (R) to cysteine (C). The child's chronological age was 4 years and 11 months, and his bone age 2 years and 6 months, i.e., equal to only 51% of his chronological age. Body proportions were normal except for the prominent forehead and saddle nose. Pituitary size was normal on magnetic resonance imaging examinations. Serum IGF-1, IGFBP-3 and GHBP were all decreased or at the lower limit of the normal range. Nocturnal urinary growth hormone (GH) excretion was high. Isoelectric focusing analysis revealed the presence of an abnormal GH peak in addition to the normal one. The R77C mutant GH possessed a 6 times greater affinity to GHBP than the wild-type GH, and inhibited tyrosine phosphorylation in IM-9 cells 10 times more potently than the wild-type GH, showing an antagonistic or a dominant negative action. In agreement with the antagonistic property of the mutant GH exhibited, the child did not show any increase in serum IGF-1 levels after exogenous hGH administration. It should be noted that the child in this study is not a typical case of Kowarski syndrome in which endogenous GH is found to be simply bioinactive, as in the patient we recently described elsewhere. Therefore, this patient's condition should be categorized as a new syndrome of short stature caused by a natural GH antagonist.

  5. Suppression of glycolate oxidase causes glyoxylate accumulation that inhibits photosynthesis through deactivating Rubisco in rice.

    PubMed

    Lu, Yusheng; Li, Yong; Yang, Qiaosong; Zhang, Zhisheng; Chen, Yan; Zhang, Sheng; Peng, Xin-Xiang

    2014-03-01

    Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with the deactivated Rubisco is likely involved in the regulation. Using isolated Rubisco and chloroplasts, it has been found that only glyoxylate can effectively inactivate Rubisco and meanwhile inhibit photosynthesis, but little in vivo evidence has been acquired and reported. In this study, we have generated the transgenic rice (Oryza sativa) plants with GLO being constitutively silenced, and conducted the physiological and biochemical analyses on these plants to explore the regulatory mechanism. When GLO was downregulated, the net photosynthetic rate (Pn) was reduced and the plant growth was correspondingly stunted. Surprisingly, glyoxylate, as a product of the GLO catalysis, was accumulated in response to the GLO suppression, like its substrate glycolate. Furthermore, the glyoxylate content was found to be inversely proportional to the Pn while the Pn is directly proportional to the Rubisco activation state in the GLO-suppressed plants. A mathematical fitting equation using least square method also demonstrated that the Rubisco activation state was inversely proportional to the glyoxylate content. Despite that the further analyses we have conducted failed to reveal how glyoxylate was accumulated in response to the GLO suppression, the current results do strongly suggest that there may exist an unidentified, alternative pathway to produce glyoxylate, and that the accumulated glyoxylate inhibits photosynthesis by deactivating Rubisco, and causes the photorespiratory phenotype in the GLO-suppressed rice plants. © 2013 Scandinavian Plant Physiology Society.

  6. Di(2-ethylhexyl) phthalate inhibits antral follicle growth, induces atresia, and inhibits steroid hormone production in cultured mouse antral follicles

    PubMed Central

    Hannon, Patrick R.; Brannick, Katherine E.; Wang, Wei; Gupta, Rupesh K.; Flaws, Jodi A.

    2015-01-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental toxicant found in consumer products that causes ovarian toxicity. Antral follicles are the functional ovarian units and must undergo growth, survival from atresia, and proper regulation of steroidogenesis to ovulate and produce hormones. Previous studies have determined that DEHP inhibits antral follicle growth and decreases estradiol levels in vitro; however, the mechanism by which DEHP elicits these effects is unknown. The present study tested the hypothesis that DEHP directly alters regulators of the cell cycle, apoptosis, and steroidogenesis to inhibit antral follicle functionality. Antral follicles from adult CD-1 mice were cultured with vehicle control or DEHP (1-100μg/ml) for 24-96 hr to establish the temporal effects of DEHP on the follicle. Following 24-96 hr of culture, antral follicles were subjected to gene expression analysis, and media were subjected to measurements of hormone levels. DEHP increased the mRNA levels of cyclin D2, cyclin dependent kinase 4, cyclin E1, cyclin A2, and cyclin B1 and decreased the levels of cyclin-dependent kinase inhibitor 1A prior to growth inhibition. Additionally, DEHP increased the mRNA levels of BCL2-associated agonist of cell death, BCL2-associated X protein, BCL2-related ovarian killer protein, B-cell leukemia/lymphoma 2, and Bcl2-like 10, leading to an increase in atresia. Further, DEHP decreased the levels of progesterone, androstenedione, and testosterone prior to the decrease in estradiol levels, with decreased mRNA levels of side-chain cleavage, 17α-hydorxylase-17,20-desmolase, 17β-hydroxysteroid dehydrogenase, and aromatase. Collectively, DEHP directly alters antral follicle functionality by inhibiting growth, inducing atresia, and inhibiting steroidogenesis. PMID:25701202

  7. Targeting fibroblast growth factor receptor signaling inhibits prostate cancer progression

    PubMed Central

    Feng, Shu; Shao, Longjiang; Yu, Wendong; Gavine, Paul; Ittmann, Michael

    2015-01-01

    Purpose Extensive correlative studies in human prostate cancer (PCa) as well as studies in vitro and in mouse models indicate that FGF receptor (FGFR) signaling plays an important role in PCa progression. In this study, we employed a probe compound for an FGFR inhibitor which potently inhibits FGFR1-3 and significantly inhibits FGFR-4. The purpose of this study is to determine if targeting FGFR signaling from all four FGFRs will have in vitro activities consistent with inhibition of tumor progression and will inhibit tumor progression in vivo. Experimental Design Effects of AZ8010 on FGFR signaling and invasion were analyzed using immortalized normal prostate epithelial (PNT1a) cells and PNT1a overexpressing FGFR-1 or FGFR-4. The effect of AZ8010 on invasion and proliferation in vitro was also evaluated in PCa cell lines. Finally, the impact of AZ8010 on tumor progression in vivo was evaluated using a VCaP xenograft model. Results AZ8010 completely inhibits FGFR-1 and significantly inhibits FGFR-4 signaling at 100 nM, which is an achievable in vivo concentration. These results in marked inhibition of ERK phosphorylation and invasion in PNT1a cells expressing FGFR-1 and FGFR-4 and all PCa cell lines tested. Treatment in vivo completely inhibited VCaP tumor growth and significantly inhibited angiogenesis and proliferation and increased cell death in treated tumors. This was associated with marked inhibition of ERK phosphorylation in treated tumors. Conclusions Targeting FGFR signaling is a promising new approach to treating aggressive PCa. PMID:22573348

  8. Amphiphilic suramin dissolves Matrigel, causing an 'inhibition' artefact within in vitro angiogenesis assays.

    PubMed

    Prigozhina, Natalie L; Heisel, Andrew J; Seldeen, Jordan R; Cosford, Nicholas D P; Price, Jeffrey H

    2013-12-01

    The field of study concerning promotion and/or inhibition of angiogenesis has gathered much attention in the scientific community. A great deal of work has been invested towards defining reproducible assays to gauge for promotion or inhibition of angiogenesis in response to drug treatments or growth conditions. Two common components of these assays were noted by our group to have an unexpected and previously unreported interaction. Suramin is a commercially available compound, commonly used as a positive control for in vitro angiogenic inhibition assays. Matrigel is a popular extracellular substrate that supports angiogenic network formation when endothelial cells are cultured on its surface. However, our group demonstrated that suramin alone (without the presence of cells) will actively dissolve Matrigel, causing the extracellular matrix to transition from the gel-like physical state to a more liquid state. This causes cells on the Matrigel to congregate and sink to the bottom of the well. Therefore, previous observations of inhibition of endothelial cell angiogenesis through the incubation with suramin (including previous observations made by our group) are, largely, an artefact caused by suramin and matrix interaction rather than suramin and cells interaction, as previously reported. Our results suggest that the presence of sulphate groups and amphiphilic properties of suramin are likely responsible for the disruption of the matrix layer. We believe that this information is of prime importance to anyone using similar in vitro models, or employing suramin in any therapy or drug development assays. © 2013 The Authors. International Journal of Experimental Pathology © 2013 International Journal of Experimental Pathology.

  9. The effect of polyamine biosynthesis inhibition on growth and differentiation of the phytopathogenic fungus Sclerotinia sclerotiorum.

    PubMed

    Pieckenstain, F L; Gárriz, A; Chornomaz, E M; Sánchez, D H; Ruiz, O A

    2001-12-01

    We studied the effects of several polyamine biosynthesis inhibitors on growth, differentiation, free polyamine levels and in vivo and in vitro activity of polyamine biosynthesis enzymes in Sclerotinia sclerotiorum. Alpha-Difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA) were potent inhibitors of mycelial growth. The effect of DFMO was due to inhibition of ornithine decarboxylase (ODC). No evidence for the existence of an arginine decarboxylase (ADC) pathway was found. The effect of DFMA was partly due to inhibition of ODC, presumably after its conversion into DFMO by mycelial arginase, as suggested by the high activity of this enzyme detected both in intact mycelium and mycelial extracts. In addition, toxic effects of DFMA on cellular processes other than polyamine metabolism might have occurred. Cyclohexylamine (CHA) slightly inhibited mycelial growth and caused an important decrease of free spermidine associated with a drastic increase of free putrescine concentration. Methylglyoxal bis-[guanyl hydrazone] (MGBG) had no effect on mycelial growth. Excepting MGBG, all the inhibitors strongly decreased sclerotial formation. Results demonstrate that sclerotial development is much more sensitive to polyamine biosynthesis inhibition than mycelial growth. Our results suggest that mycelial growth can be supported either by spermidine or putrescine, while spermidine (or the putrescine/spermidine ratio) is important for sclerotial formation to occur. Ascospore germination was completely insensitive to the inhibitors.

  10. Saccharin and cyclamate inhibit binding of epidermal growth factor.

    PubMed Central

    Lee, L S

    1981-01-01

    The binding of 125I-labeled mouse epidermal growth factor (EGF) to 18 cell lines, including HeLa (human carcinoma), MDCK (dog kidney cells), HTC (rat hepatoma), K22 (rat liver), HF (human foreskin), GM17 (human skin fibroblasts), XP (human xeroderma pigmentosum fibroblasts), and 3T3-L1 (mouse fibroblasts), was inhibited by saccharin and cyclamate. The human cells were more sensitive to inhibition by these sweeteners than mouse or rat cells. EGF at doses far above the physiological levels reversed the inhibition in rodent cells but not in HeLa cells. In HeLa cells, the doses of saccharin and cyclamate needed for 50% inhibition were 3.5 and 9.3 mg/ml, respectively. Glucose, 2-deoxyglucose, sucrose, and xylitol did not inhibit EGF binding. Previous studies have shown that phorbol esters, strongly potent tumor promoters, also inhibit EGF binding to tissue culture cells. To explain the EGF binding inhibition by such greatly dissimilar molecules as phorbol esters, saccharin, and cyclamate, it is suggested that they operate through the activation of a hormone response control unit. PMID:6262753

  11. Saccharin and Cyclamate Inhibit Binding of Epidermal Growth Factor

    NASA Astrophysics Data System (ADS)

    Lee, L. S.

    1981-02-01

    The binding of 125I-labeled mouse epidermal growth factor (EGF) to 18 cell lines, including HeLa (human carcinoma), MDCK (dog kidney cells), HTC (rat hepatoma), K22 (rat liver), HF (human foreskin), GM17 (human skin fibroblasts), XP (human xeroderma pigmentosum fibroblasts), and 3T3-L1 (mouse fibroblasts), was inhibited by saccharin and cyclamate. The human cells were more sensitive to inhibition by these sweeteners than mouse or rat cells. EGF at doses far above the physiological levels reversed the inhibition in rodent cells but not in HeLa cells. In HeLa cells, the doses of saccharin and cyclamate needed for 50% inhibition were 3.5 and 9.3 mg/ml, respectively. Glucose, 2-deoxyglucose, sucrose, and xylitol did not inhibit EGF binding. Previous studies have shown that phorbol esters, strongly potent tumor promoters, also inhibit EGF binding to tissue culture cells. To explain the EGF binding inhibition by such greatly dissimilar molecules as phorbol esters, saccharin, and cyclamate, it is suggested that they operate through the activation of a hormone response control unit.

  12. The role of nitric oxide in the coronary vasoconstriction caused by growth hormone in anaesthetized pigs.

    PubMed

    Molinari, C; Battaglia, A; Bona, G; Grossini, E; Mary, D A; Vacca, G

    2000-03-01

    Intravenous injection of growth hormone in anaesthetized pigs has been shown to cause coronary vasoconstriction by antagonizing the vasodilatory effects of 2-adrenergic receptors. Because nitric oxide is believed to modulate or mediate 2-adrenergic effects, the present study was undertaken in the same experimental model to determine the role of nitric oxide in the above response to growth hormone. In fourteen pigs anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary blood flow caused by intravenous injection of 0.05 i.u. kg-1 of growth hormone at constant heart rate and arterial blood pressure were assessed using electromagnetic flowmeters. In a first control group of six pigs, growth hormone caused a decrease in coronary blood flow which averaged 13.1 % of the baseline values. In a second group of eight pigs, intravenous administration of N-nitro-L-arginine methyl ester (L-NAME) was used to block the endothelial release of nitric oxide. In these pigs, the subsequent injection of growth hormone did not cause any significant changes in coronary blood flow, even when performed after reversing the increase in arterial blood pressure and coronary vascular resistance caused by L-NAME with continuous intravenous infusion of papaverine. These results indicated that the coronary vasoconstricting effect of growth hormone, known to involve antagonism of 2-adrenergic vasodilatory effect, was mediated by inhibition of nitric oxide release.

  13. Gradient microfluidics enables rapid bacterial growth inhibition testing.

    PubMed

    Li, Bing; Qiu, Yong; Glidle, Andrew; McIlvenna, David; Luo, Qian; Cooper, Jon; Shi, Han-Chang; Yin, Huabing

    2014-03-18

    Bacterial growth inhibition tests have become a standard measure of the adverse effects of inhibitors for a wide range of applications, such as toxicity testing in the medical and environmental sciences. However, conventional well-plate formats for these tests are laborious and provide limited information (often being restricted to an end-point assay). In this study, we have developed a microfluidic system that enables fast quantification of the effect of an inhibitor on bacteria growth and survival, within a single experiment. This format offers a unique combination of advantages, including long-term continuous flow culture, generation of concentration gradients, and single cell morphology tracking. Using Escherichia coli and the inhibitor amoxicillin as one model system, we show excellent agreement between an on-chip single cell-based assay and conventional methods to obtain quantitative measures of antibiotic inhibition (for example, minimum inhibition concentration). Furthermore, we show that our methods can provide additional information, over and above that of the standard well-plate assay, including kinetic information on growth inhibition and measurements of bacterial morphological dynamics over a wide range of inhibitor concentrations. Finally, using a second model system, we show that this chip-based systems does not require the bacteria to be labeled and is well suited for the study of naturally occurring species. We illustrate this using Nitrosomonas europaea, an environmentally important bacteria, and show that the chip system can lead to a significant reduction in the period required for growth and inhibition measurements (<4 days, compared to weeks in a culture flask).

  14. FX11 inhibits aerobic glycolysis and growth of neuroblastoma cells.

    PubMed

    Rellinger, Eric J; Craig, Brian T; Alvarez, Alexandra L; Dusek, Haley L; Kim, Kwang W; Qiao, Jingbo; Chung, Dai H

    2017-03-01

    The MYC family of proteins promotes neuroblastoma tumorigenesis at least in part through the induction of aerobic glycolysis by promoting the transcription of key glycolytic enzymes, such as LDHA. FX11 is a selective inhibitor of LDHA that has demonstrated preclinical efficacy in adult cancers. Herein, we hypothesized that FX11 would inhibit aerobic glycolysis and block growth of neuroblastoma cells. We surveyed 3 MYCN-single copy and 5 MYCN-amplified neuroblastoma cell lines to correlate C-MYC/N-MYC protein levels with LDHA expression. Cell viability was measured with FX11 using a tetrazolium-based assay. Cell cycle analysis using propidium iodide with flow cytometry was performed to evaluate for growth arrest. Immunoblotting demonstrated PARP and Caspase 3 cleavage as evidence of apoptosis. LDHA is frequently expressed in both MYCN--amplified and MYCN-single copy cell lines. N-MYC and C-MYC protein levels did not correlate with LDHA protein expression. FX11 inhibits aerobic glycolysis and growth in three MYCN-amplified and one MYCN-single copy neuroblastoma cell lines. FX11 induces modest G1 cell cycle arrest with selective induction of apoptosis. Small molecule LDHA inhibition is capable of blocking aerobic glycolysis and growth of neuroblastoma cell lines in vitro and merits further in vivo evaluation of its preclinical efficacy in neuroblastomas. Copyright © 2016. Published by Elsevier Inc.

  15. A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity.

    PubMed

    Aquea, Felipe; Federici, Fernan; Moscoso, Cristian; Vega, Andrea; Jullian, Pastor; Haseloff, Jim; Arce-Johnson, Patricio

    2012-04-01

    Boron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We show that application of BA reduces the size of root meristems, correlating with the inhibition of root growth. The decrease in meristem size is caused by a reduction of cell division. Mitotic cell number significantly decreases and the expression level of key core cell cycle regulators is modulated. The modulation of the cell cycle does not appear to act through cytokinin and auxin signalling. A global expression analysis reveals that boron toxicity induces the expression of genes related with abscisic acid (ABA) signalling, ABA response and cell wall modifications, and represses genes that code for water transporters. These results suggest that boron toxicity produces a reduction of water and BA uptake, triggering a hydric stress response that produces root growth inhibition.

  16. Midazolam Induces Cellular Apoptosis in Human Cancer Cells and Inhibits Tumor Growth in Xenograft Mice

    PubMed Central

    Mishra, Siddhartha Kumar; Kang, Ju-Hee; Lee, Chang Woo; Oh, Seung Hyun; Ryu, Jun Sun; Bae, Yun Soo; Kim, Hwan Mook

    2013-01-01

    Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosis-inducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties. PMID:24008365

  17. A novel anticancer agent SNG1153 inhibits growth of lung cancer stem/progenitor cells

    PubMed Central

    Wang, Jing; Zhu, Hai; Han, Yuqing; Jin, Mingji; Wang, Jun; Zhou, Congya; Ma, Junfeng; Lin, Qingcong; Wang, Zhaoyi; Meng, Kun; Fu, Xueqi

    2016-01-01

    Lung cancer is the leading cause of cancer-related death in both men and women. Lung cancer contains a small population of cancer cells with stem-like features known as cancer stem cells (CSCs). CSCs are often more resistant to current therapeutic treatments. Thus, it is urgent to develop a novel agent that is able to inhibit CSCs growth. In this study, we examined the ability of SNG1153, a novel chemical agent to inhibit the growth of lung CSCs. We found that SNG1153 inhibited growth and induced apoptosis in established lung cancer cells. We also found that SNG1153 inhibited the tumorsphere formation and decreased CD133-positive (lung CSC marker) cancer cells. SNG1153 was able to attenuate tumor formation in NOD/SCID (non-obese diabetic/severe combined immunodeficient) mice injected with lung tumorsphere cells. We further demonstrated that SNG1153 induced β-catenin phosphorylation and down-regulated β-catenin. Our results thus demonstrate that SNG1153 effectively inhibits the growth of lung CSCs and suggest that SNG1153 may be a novel therapeutic agent to treat human lung cancer. PMID:27281614

  18. Tamoxifen inhibits mitochondrial membrane damage caused by disulfiram.

    PubMed

    Pavón, Natalia; Buelna-Chontal, Mabel; Correa, Francisco; Yoval-Sánchez, Belem; Belmont, Javier; Hernández-Esquivel, Luz; Rodríguez-Zavala, José S; Chávez, Edmundo

    2017-10-01

    In this work, we studied the protective effects of tamoxifen (TAM) on disulfiram (Dis)-induced mitochondrial membrane insult. The results indicate that TAM circumvents the inner membrane leakiness manifested as Ca(2+) release, mitochondrial swelling, and collapse of the transmembrane electric gradient. Furthermore, it was found that TAM prevents inactivation of the mitochondrial enzyme aconitase and detachment of cytochrome c from the inner membrane. Interestingly, TAM also inhibited Dis-promoted generation of hydrogen peroxide. Given that TAM is an antioxidant molecule, it is plausible that its protection may be due to the inhibition of Dis-induced oxidative stress.

  19. Safranal and its analogs inhibit Escherichia coli ATP synthase and cell growth.

    PubMed

    Liu, Mason; Amini, Amon; Ahmad, Zulfiqar

    2017-02-01

    Safranal, a dominant component of saffron, is known to have antitumor, cytotoxic, and antibacterial properties. In this study, we examined safranal and its structural analogs-thymol, carvacrol, damascenone, cuminol, 2,6,6-trimethyl-2-cyclohexene-1,4-dione (TMCHD), 4-isopropylbenzyl bromide (IPBB), and 4-tert-butylphenol (TBP) induced inhibition of Escherichia coli membrane bound F1Fo ATP synthase. Safranal and its analogs inhibited wild-type enzyme to variable degrees. While safranal caused 100% inhibition of wild-type F1Fo ATP synthase, only about 50% inhibition occurred for αR283D mutant ATP synthase. Moreover, safranal, thymol, carvacrol, damascenone, cuminol, TMCHD, IPBB, and TBP all fully abrogated the growth of wild-type E. coli cells and had partial or no effect on the growth of null and mutant E. coli strains. Therefore, the antimicrobial properties of safranal, thymol, carvacrol, damascenone, cuminol, TMCHD, IPBB, and TBP can be linked to their binding and inhibition of ATP synthase. Total loss of growth in wild-type and partial or no growth loss in null or mutant E. coli strains demonstrates that ATP synthase is a molecular target for safranal and its structural analogs. Partial inhibition of the αArg-283 mutant enzyme establishes that αArg-283 residue is required in the polyphenol binding pocket of ATP synthase for the binding of safranal. Furthermore, partial growth loss for the null and mutant strains in the presence of inhibitors also suggests the role of other targets and residues in the process of inhibition.

  20. Vascular endothelial-derived semaphorin 3 inhibits sympathetic axon growth.

    PubMed

    Damon, Deborah H

    2006-03-01

    Vascular sympathetic innervation is an important determinant of blood pressure and blood flow. The mechanisms that determine vascular sympathetic innervation are not well understood. Recent studies indicate that vascular endothelial cells (EC) express semaphorin 3A, a repulsive axon guidance cue. This suggests that EC would inhibit the growth of axons to blood vessels. The present study tests this hypothesis. RT-PCR and Western analyses confirmed that rat aortic vascular ECs expressed semaphorin 3A as well as other class 3 semaphorins (sema 3s). To determine the effects of EC-derived sema 3 on sympathetic axons, axon outgrowth was assessed in cultures of neonatal sympathetic ganglia grown for 72 h in the absence and presence of vascular EC. Nerve growth factor-induced axon growth in the presence of ECs was 50 +/- 4% (P < 0.05) of growth in the absence of ECs. ECs did not inhibit axon growth in the presence of an antibody that neutralized the activity of sema 3 (P > 0.05). RT-PCR and Western analyses also indicated that sema 3s were expressed in ECs of intact arteries. To assess the function of sema 3s in arteries, sympathetic ganglia were grown in the presence of arteries for 72 h, and the percentage of axons that grew toward the artery was determined: 44 +/- 4% of axons grew toward neonatal carotid arteries. Neutralization of sema 3s or removal of EC increased the percentage of axons that grew toward the artery (71 +/- 8% and 72 +/- 8%, respectively). These data indicate that vascular EC-derived sema 3s inhibit sympathetic axon growth and may thus be a determinant of vascular sympathetic innervation.

  1. The rhizobacterium Arthrobacter agilis produces dimethylhexadecylamine, a compound that inhibits growth of phytopathogenic fungi in vitro.

    PubMed

    Velázquez-Becerra, Crisanto; Macías-Rodríguez, Lourdes I; López-Bucio, José; Flores-Cortez, Idolina; Santoyo, Gustavo; Hernández-Soberano, Christian; Valencia-Cantero, Eduardo

    2013-12-01

    Plant diseases caused by fungal pathogens such as Botrytis cinerea and the oomycete Phytophthora cinnamomi affect agricultural production worldwide. Control of these pests can be done by the use of fungicides such as captan, which may have deleterious effects on human health. This study demonstrates that the rhizobacterium Arthrobacter agilis UMCV2 produces volatile organic compounds that inhibit the growth of B. cinerea in vitro. A single compound from the volatile blends, namely dimethylhexadecylamine (DMHDA), could inhibit the growth of both B. cinerea and P. cinnamomi when supplied to the growth medium in low concentrations. DMHDA also inhibited the growth of beneficial fungi Trichoderma virens and Trichoderma atroviride but at much higher concentrations. DMHDA-related aminolipids containing 4, 8, 10, 12, and 14 carbons in the alkyl chain were tested for their inhibitory effect on the growth of the pathogens. The results show that the most active compound from those tested was dimethyldodecylamine. This effect correlates with a decrease in the number of membrane lipids present in the mycelium of the pathogen including eicosanoic acid, (Z)-9-hexadecenoic acid, methyl ester, and (Z)-9-octadecenoic acid, methyl ester. Strawberry leaflets treated with DMHDA were not injured by the compound. These data indicate that DMHDA and related compounds, which can be produced by microorganisms may effectively inhibit the proliferation of certain plant pathogens.

  2. Growth of antarctic cyanobacteria under ultraviolet radiation: UVA counteracts UVB inhibition

    SciTech Connect

    Quesada, A. |; Mouget, J.L.; Vincent, W.F.

    1995-04-01

    A mat-forming cyanobacterium (Phormidium murayi West and West) isolated from an ice-shelf pond in Antarctica was grown under white light combined with a range of UVA and UVB irradiance. The 4-day growth rate decreased under increasing ultraviolet (UV) radiation, with a ninefold greater response to UVB relative to UVA. In vivo absorbance spectra showed that UVA and to a greater extent UVB caused a decrease in phycocyanin/chlorophyll a and an increase in carotenoids/chlorophyll a. The phycocyanin/chlorophyll a ratio was closely and positively correlated to the UVB-inhibited growth rate. Under fixed spectral gradients of UV radiation, the growth inhibition effect was dominated by UVB. However, at specific UVB irradiances the inhibition of growth depended on the ratio of UVB to UVA, and growth rates increased linearly with increasing UVA. These results are consistent with the view that UVB inhibition represents the balance between damage and repair processes that are each controlled by separate wavebands. They also underscore the need to consider UV spectral balance in laboratory and field assays of UVB toxicity. 49 refs., 6 figs.

  3. Di (2-ethylhexyl) phthalate inhibits growth of ovarian antral follicles through an oxidative stress pathway

    PubMed Central

    Wang, Wei; Craig, Zelieann R.; Basavarajappa, Mallikarjuna S.; Gupta, Rupesh; Flaws, Jodi A.

    2011-01-01

    Di (2-ethylhexyl) phthalate (DEHP) is a plasticizer that has been shown to inhibit growth of mouse antral follicles, however, little is known about the mechanisms by which DEHP does so. Oxidative stress has been linked to follicle growth inhibition as well as phthalate-induced toxicity in non-ovarian tissues. Thus, we hypothesized that DEHP causes oxidative stress and that this leads to inhibition of the growth of antral follicles. To test this hypothesis, antral follicles isolated from CD-1 mice (age 32–35 days) were cultured with vehicle control (dimethylsulfoxide [DMSO]) or DEHP (1–100μg/ml) ± N-acetyl cysteine (NAC, an antioxidant at 0.25–1mM). During culture, follicles were measured daily. At the end of culture, follicles were collected and processed for in vitro reactive oxygen species (ROS) assays to measure the presence of free radicals or for measurement of the expression and activity of various key antioxidant enzymes: Cu/Zn superoxide dismutase (SOD1), glutathione peroxidase (GPX) and catalase (CAT). The results indicate that DEHP inhibits the growth of follicles compared to DMSO control and that NAC (0.25–1mM) blocks the ability of DEHP to inhibit follicle growth. Furthermore, DEHP (10μg/ml) significantly increases ROS levels and reduces the expression and activity of SOD1 compared to DMSO controls, whereas NAC (0.5mM) rescues the effects of DEHP on ROS levels and SOD1. However, the expression and activity of GPX and CAT were not affected by DEHP treatment. Collectively, these data suggest that DEHP inhibits follicle growth by inducing production of ROS and by decreasing the expression and activity of SOD1. PMID:22155089

  4. Pentamidine Inhibition of Group I Intron Splicing in Candida albicans Correlates with Growth Inhibition

    PubMed Central

    Miletti, Karl E.; Leibowitz, Michael J.

    2000-01-01

    We previously demonstrated that pentamidine, which has been clinically used against Pneumocystis carinii, inhibits in vitro a group I intron ribozyme from that organism. Another fungal pathogen, Candida albicans, also harbors a group I intron ribozyme (Ca.LSU) in the essential rRNA genes in almost half of the clinical isolates analyzed. To determine whether pentamidine inhibits Ca.LSU in vitro and in cells, phylogenetically closely related intron-containing (4-1) and intronless (62-1) strains were studied. Splicing in vitro of the Ca.LSU group I intron ribozyme was completely inhibited by pentamidine at 200 μM. On rich glucose medium, the intron-containing strain was more sensitive to growth inhibition by pentamidine than was the intronless strain, as measured by disk or broth microdilution assays. On rich glycerol medium, they were equally susceptible to pentamidine. At pentamidine levels selectively inhibiting the intron-containing strain (1 μM) in glucose liquid cultures, inhibition of splicing and rRNA maturation was detected by quantitative reverse transcription-PCR within 1 min with a 10- to 15-fold accumulation of precursor rRNA. No comparable effect was seen in the intronless strain. These results correlate the cellular splicing inhibition of Ca.LSU with the growth inhibition of strain 4-1 harboring Ca.LSU. Broth microdilution assays of 13 Candida strains showed that intron-containing strains were generally more susceptible to pentamidine than the intronless strains. Our data suggest that ribozymes found in pathogenic microorganisms but absent in mammals may be targets for antimicrobial therapy. PMID:10722497

  5. Cerium relieves the inhibition of nitrogen metabolism of spinach caused by magnesium deficiency.

    PubMed

    Yin, Sitao; Ze, Yuguan; Liu, Chao; Li, Na; Zhou, Min; Duan, Yanmei; Hong, Fashui

    2009-12-01

    Magnesium is one of the essential elements for plant growth and cerium is a beneficial element for plant growth. However, the effects of the fact that cerium improves the nitrogen metabolism of plants under magnesium deficiency is poorly understood. The main aim of the study was to determine the role of cerium in the amelioration of magnesium-deficiency effects in spinach plants. Spinach plants were cultivated in Hoagland's solution. They were subjected to magnesium deficiency and to cerium chloride administered in the magnesium-present media and magnesium-deficient media. Spinach plants grown in the magnesium-present media and magnesium-deficient media were measured for key enzyme activities involved in nitrogen metabolism such as nitrate reductase, nitrite reductase, glutamate dehydrogenase, glutamate synthase, urease, glutamic–pyruvic transaminase, and glutamic–oxaloace protease transaminase. As the nitrogen metabolism in spinach was significantly inhibited by magnesium deficiency, it caused a significant reduction of spinach plant weight, leaf turning chlorosis. However, cerium treatment grown in magnesium-deficiency media significantly promoted the activities of the key enzymes as well as the contents of the free amino acids, chlorophyll, soluble protein, and spinach growth. It implied that Ce3+ could partly substitute for magnesium to facilitate the transformation from inorganic nitrogen to organic nitrogen, leading to the improvement of spinach growth, although the metabolism needs to be investigated further.

  6. Lime-amended growing medium causes seedling growth distortions

    Treesearch

    R. Kasten Dumroese; Gale Thompson; David L. Wenny

    1990-01-01

    Although a commercial growing medium with incorporated agricultural lime had been successfully used for years, it caused growth distortion of coniferous and deciduous seedlings during 1988. Seedlings grown in the amended medium were stunted and chlorotic, often with disfigured needles and multiple tops. Seedlings grown in the same medium without incorporated lime grew...

  7. Proteasome Inhibition by Fellutamide B Induces Nerve Growth Factor Synthesis

    PubMed Central

    Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M.

    2008-01-01

    SUMMARY Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High resolution structural information obtained from co-crystallization of the 20S proteasome reveals novel aspects regarding β-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

  8. Phytotoxicity of coloured substances: is Lemna duckweed an alternative to the algal growth inhibition test?

    PubMed

    Cleuvers, Michael; Ratte, Hans-Toni

    2002-10-01

    Coloured substances cause problems when interpreting algal tests, because effects due to light absorption can interact with potential toxicity. The Lemna Duckweed growth inhibition test can complement the algal test, on condition that the test is performed on a black, not reflecting surface. On white surfaces, test solution colour can strongly impact Lemna growth. For example, average control sample growth rate of is much higher on white surfaces (0.362 d(-1)) than on black surfaces (0.284 d(-1)). We found that 10 mg l(-1) of the dyestuff "Brilliant Blue R spezial" inhibited average Lemna growth rate about 22% on white surfaces but did not inhibit growth on black surfaces. The reason for this difference stems from the difference in amount of light reflected from below the test beakers. With Brilliant Blue on white surfaces, the test solution colour reduces utilizable light and causes a deterioration of light conditions, whereas on a black surfaces, reflected light is absent a priori, and thus no inhibiting effect was measured. Of particular importance is the choice of test parameter. With Brilliant Blue, a LOEC for average growth rate, based on frond numbers, of 320 mg l(-1) was determined. However, when average growth rate was calculated using dry weights of the plants, the LOEC decreased clearly to 1.0 mg l(-1). In this study, the Lemna test was much more sensitive than the algal test. We recommend Lemna tests be used in addition to algal tests, because doing so may significantly improve the assessment of phytotoxicity of chemicals and sewage.

  9. Fucoidan Inhibits the Growth of Hepatocellular Carcinoma Independent of Angiogenesis

    PubMed Central

    Zhu, Cong; Cao, Rui; Zhang, Shuang-Xia; Man, Ya-Nan; Wu, Xiong-Zhi

    2013-01-01

    Some sulphated polysaccharides can bind bFGF but are unable to present bFGF to its high-affinity receptors. Fucoidan, a sulphated polysaccharide purified from brown algae, which has been used as an anticancer drug in traditional Chinese medicine for hundreds of years, exhibits a variety of anticancer effects, including the induction of the apoptosis and autophagy of cancer cells, the inhibition of the growth of cancer cells, the induction of angiogenesis, and the improvement of antitumour immunity. Our research shows that fucoidan dose not inhibit the expressions of VEGF, bFGF, IL-8, and heparanase in HCC cells and/or tumour tissues. Moreover, fucoidan exhibited low affinity for bFGF and could not block the binding of bFGF to heparan sulphated. Although fucoidan had no effect on angiogenesis and apoptosis in vivo, this drug significantly inhibited the tumour growth and the expression of PCNA. These results suggest that fucoidan exhibits an anticancer effect in vivo at least partly through inhibition of the proliferation of HCC cells, although it is unable to suppress the angiogenesis induced by HCC. PMID:23737842

  10. 3-Bromopyruvate inhibits human gastric cancer tumor growth in nude mice via the inhibition of glycolysis.

    PubMed

    Xian, Shu-Lin; Cao, Wei; Zhang, Xiao-Dong; Lu, Yun-Fei

    2015-02-01

    Tumor cells primarily depend upon glycolysis in order to gain energy. Therefore, the inhibition of glycolysis may inhibit tumor growth. Our previous study demonstrated that 3-bromopyruvate (3-BrPA) inhibited gastric cancer cell proliferation in vitro. However, the ability of 3-BrPA to suppress tumor growth in vivo, and its underlying mechanism, have yet to be elucidated. The aim of the present study was to investigate the inhibitory effect of 3-BrPA in an animal model of gastric cancer. It was identified that 3-BrPA exhibited strong inhibitory effects upon xenograft tumor growth in nude mice. In addition, the antitumor function of 3-BrPA exhibited a dose-effect association, which was similar to that of the chemotherapeutic agent, 5-fluorouracil. Furthermore, 3-BrPA exhibited low toxicity in the blood, liver and kidneys of the nude mice. The present study hypothesized that the inhibitory effect of 3-BrPA is achieved through the inhibition of hexokinase activity, which leads to the downregulation of B-cell lymphoma 2 (Bcl-2) expression, the upregulation of Bcl-2-associated X protein expression and the subsequent activation of caspase-3. These data suggest that 3-BrPA may be a novel therapy for the treatment of gastric cancer.

  11. Targeting GIPC/synectin in pancreatic cancer inhibits tumor growth.

    PubMed

    Muders, Michael H; Vohra, Pawan K; Dutta, Shamit K; Wang, Enfeng; Ikeda, Yasuhiro; Wang, Ling; Udugamasooriya, D Gomika; Memic, Adnan; Rupasinghe, Chamila N; Rupashinghe, Chamila N; Baretton, Gustavo B; Aust, Daniela E; Langer, Silke; Datta, Kaustubh; Simons, Michael; Spaller, Mark R; Mukhopadhyay, Debabrata

    2009-06-15

    Various studies have shown the importance of the GAIP interacting protein, COOH-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth-promoting receptors such as insulin-like growth factor receptor I (IGF-IR) and integrins. These interactions were mediated through its PDZ domain. GIPC/Synectin has been shown to be overexpressed in pancreatic and breast cancer. The goal of this study was to show the importance of GIPC/Synectin in pancreatic cancer growth and to evaluate a possible therapeutic strategy by using a GIPC-PDZ domain inhibitor. Furthermore, the effect of targeting GIPC on the IGF-I receptor as one of its associated receptors was tested. The in vivo effects of GIPC/Synectin knockdown were studied after lentiviral transduction of luciferase-expressing pancreatic cancer cells with short hairpin RNA against GIPC/Synectin. Additionally, a GIPC-PDZ--targeting peptide was designed. This peptide was tested for its influence on pancreatic cancer growth in vitro and in vivo. Knockdown of GIPC/Synectin led to a significant inhibition of pancreatic adenocarcinoma growth in an orthotopic mouse model. Additionally, a cell-permeable GIPC-PDZ inhibitor was able to block tumor growth significantly without showing toxicity in a mouse model. Targeting GIPC was accompanied by a significant reduction in IGF-IR expression in pancreatic cancer cells. Our findings show that targeting GIPC/Synectin and its PDZ domain inhibits pancreatic carcinoma growth and is a potential strategy for therapeutic intervention of pancreatic cancer.

  12. Equol inhibits growth, induces atresia, and inhibits steroidogenesis of mouse antral follicles in vitro

    PubMed Central

    Mahalingam, Sharada; Gao, Liying; Gonnering, Marni; Helferich, William; Flaws, Jodi A.

    2016-01-01

    Equol is a non-steroidal estrogen metabolite produced by microbial conversion of daidzein, a major soy isoflavone, in the gut of some humans and many animal species. Isoflavones and their metabolites can affect endogenous estradiol production, action, and metabolism, potentially influencing ovarian follicle function. However, no studies have examined the effects of equol on intact ovarian antral follicles, which are responsible for sex steroid synthesis and further development into ovulatory follicles. Thus, the present study tested the hypothesis that equol inhibits antral follicle growth, increases follicle atresia, and inhibits steroidogenesis in the adult mouse ovary. To test this hypothesis, antral follicles isolated from adult CD-1 mice were cultured with vehicle control (dimethyl sulfoxide; DMSO) or equol (600 nM, 6 μM, 36 μM, 100 μM) for 48 and 96 h. Every 24 h, follicle diameters were measured to monitor growth. At 48 and 96 h, the culture medium was subjected to measurement of hormone levels, and the cultured follicles were subjected to gene expression analysis. Additionally, follicles were histologically evaluated for signs of atresia after 96 h of culture. The results indicate that equol (100 μM) inhibited follicle growth, altered the mRNA levels of bcl2-associated X protein and B cell leukemia/lymphoma 2, and induced follicle atresia. Further, equol decreased the levels of estradiol, testosterone, androstenedione, and progesterone, and it decreased mRNA levels of cholesterol side-chain cleavage, steroid 17-α-hydroxalase, and aromatase. Collectively, these data indicate that equol inhibits growth, increases atresia, and inhibits steroidogenesis of cultured mouse antral follicles. PMID:26876617

  13. CI-988 Inhibits EGFR Transactivation and Proliferation Caused by Addition of CCK/Gastrin to Lung Cancer Cells.

    PubMed

    Moody, Terry W; Nuche-Berenguer, Bernardo; Moreno, Paola; Jensen, Robert T

    2015-07-01

    Cholecystokinin (CCK) receptors are G-protein coupled receptors (GPCR) which are present on lung cancer cells. CCK-8 stimulates the proliferation of lung cancer cells, whereas the CCK2R receptor antagonist CI-988 inhibits proliferation. GPCR for some gastrointestinal hormones/neurotransmitters mediate lung cancer growth by causing epidermal growth factor receptor (EGFR) transactivation. Here, the role of CCK/gastrin and CI-988 on EGFR transactivation and lung cancer proliferation was investigated. Addition of CCK-8 or gastrin-17 (100 nM) to NCI-H727 human lung cancer cells increased EGFR Tyr(1068) phosphorylation after 2 min. The ability of CCK-8 to cause EGFR tyrosine phosphorylation was blocked by CI-988, gefitinib (EGFR tyrosine kinase inhibitor), PP2 (Src inhibitor), GM6001 (matrix metalloprotease inhibitor), and tiron (superoxide scavenger). CCK-8 nonsulfated and gastrin-17 caused EGFR transactivation and bound with high affinity to NCI-H727 cells, suggesting that the CCK2R is present. CI-988 inhibited the ability of CCK-8 to cause ERK phosphorylation and elevate cytosolic Ca(2+). CI-988 or gefitinib inhibited the basal growth of NCI-H727 cells or that stimulated by CCK-8. The results indicate that CCK/gastrin may increase lung cancer proliferation in an EGFR-dependent manner.

  14. Inhibition of platelet-derived growth factor signaling prevents muscle fiber growth during skeletal muscle hypertrophy.

    PubMed

    Sugg, Kristoffer B; Korn, Michael A; Sarver, Dylan C; Markworth, James F; Mendias, Christopher L

    2017-03-01

    The platelet-derived growth factor receptors alpha and beta (PDGFRα and PDGFRβ) mark fibroadipogenic progenitor cells/fibroblasts and pericytes in skeletal muscle, respectively. While the role that these cells play in muscle growth and development has been evaluated, it was not known whether the PDGF receptors activate signaling pathways that control transcriptional and functional changes during skeletal muscle hypertrophy. To evaluate this, we inhibited PDGFR signaling in mice subjected to a synergist ablation muscle growth procedure, and performed analyses 3 and 10 days after induction of hypertrophy. The results from this study indicate that PDGF signaling is required for fiber hypertrophy, extracellular matrix production, and angiogenesis that occur during muscle growth.

  15. Inhibition of Mycoplasma pneumoniae growth by FDA-approved anticancer and antiviral nucleoside and nucleobase analogs

    PubMed Central

    2013-01-01

    Background Mycoplasma pneumoniae (Mpn) is a human pathogen that causes acute and chronic respiratory diseases and has been linked to many extrapulmonary diseases. Due to the lack of cell wall, Mpn is resistant to antibiotics targeting cell wall synthesis such as penicillin. During the last 10 years macrolide-resistant Mpn strains have been frequently reported in Asian countries and have been spreading to Europe and the United States. Therefore, new antibiotics are needed. In this study, 30 FDA-approved anticancer or antiviral drugs were screened for inhibitory effects on Mpn growth and selected analogs were further characterized by inhibition of target enzymes and metabolism of radiolabeled substrates. Results Sixteen drugs showed varying inhibitory effects and seven showed strong inhibition of Mpn growth. The anticancer drug 6-thioguanine had a MIC (minimum inhibitory concentration required to cause 90% of growth inhibition) value of 0.20 μg ml-1, whereas trifluorothymidine, gemcitabine and dipyridamole had MIC values of approximately 2 μg ml-1. In wild type Mpn culture the presence of 6-thioguanine and dipyridamole strongly inhibited the uptake and metabolism of hypoxanthine and guanine while gemcitabine inhibited the uptake and metabolism of all nucleobases and thymidine. Trifluorothymidine and 5-fluorodeoxyuridine, however, stimulated the uptake and incorporation of radiolabeled thymidine and this stimulation was due to induction of thymidine kinase activity. Furthermore, Mpn hypoxanthine guanine phosphoribosyl transferase (HPRT) was cloned, expressed, and characterized. The 6-thioguanine, but not other purine analogs, strongly inhibited HPRT, which may in part explain the observed growth inhibition. Trifluorothymidine and 5-fluorodeoxyuridine were shown to be good substrates and inhibitors for thymidine kinase from human and Mycoplasma sources. Conclusion We have shown that several anticancer and antiviral nucleoside and nucleobase analogs are potent

  16. Inhibition of Nb2 T-lymphoma cell growth by transforming growth factor-beta.

    PubMed Central

    Rayhel, E J; Prentice, D A; Tabor, P S; Flurkey, W H; Geib, R W; Laherty, R F; Schnitzer, S B; Chen, R; Hughes, J P

    1988-01-01

    Transforming growth factor-beta (TGF-beta) inhibits proliferation of Nb2 cells, a rat T lymphoma, in response to lactogens and interleukin-2. Prostaglandins may play an important role in the pathway through which TGF-beta exerts its inhibitory actions, because prostaglandin E2 also inhibits proliferation of Nb2 cells, and indomethacin, an inhibitor of prostaglandin synthesis, reverses the inhibitory effects of TGF-beta on Nb2 cell proliferation. PMID:3262338

  17. Hydroxyapatite Growth Inhibition Effect of Pellicle Statherin Peptides.

    PubMed

    Xiao, Y; Karttunen, M; Jalkanen, J; Mussi, M C M; Liao, Y; Grohe, B; Lagugné-Labarthet, F; Siqueira, W L

    2015-08-01

    In our recent studies, we have shown that in vivo-acquired enamel pellicle is a sophisticated biological structure containing a significant portion of naturally occurring salivary peptides. From a functional aspect, the identification of peptides in the acquired enamel pellicle is of interest because many salivary proteins exhibit functional domains that maintain the activities of the native protein. Among the in vivo-acquired enamel pellicle peptides that have been newly identified, 5 peptides are derived from statherin. Here, we assessed the ability of these statherin pellicle peptides to inhibit hydroxyapatite crystal growth. In addition, atomistic molecular dynamics (MD) simulations were performed to better understand the underlying physical mechanisms of hydroxyapatite growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite growth. Statherin protein, 5 statherin-derived peptides, and a peptide lacking phosphate at residues 2 and 3 were analyzed. Statherin peptide phosphorylated on residues 2 and 3 indicated a significant inhibitory effect when compared with the 5 other peptides (P < 0.05). MD simulations showed a strong affinity and fast adsorption to hydroxyapatite for phosphopeptides, whereas unphosphorylated peptides interacted weakly with the hydroxyapatite. Our data suggest that the presence of a covalently linked phosphate group (at residues 2 and 3) in statherin peptides modulates the effect of hydroxyapatite growth inhibition. This study provides a mechanism to account for the composition and function of acquired enamel pellicle statherin peptides that will contribute as a base for the development of biologically stable and functional synthetic peptides for therapeutic use against dental caries and/or periodontal disease.

  18. Multi-targeted inhibition of tumor growth and lung metastasis by redox-sensitive shell crosslinked micelles loading disulfiram

    NASA Astrophysics Data System (ADS)

    Duan, Xiaopin; Xiao, Jisheng; Yin, Qi; Zhang, Zhiwen; Yu, Haijun; Mao, Shirui; Li, Yaping

    2014-03-01

    Metastasis, the main cause of cancer related deaths, remains the greatest challenge in cancer treatment. Disulfiram (DSF), which has multi-targeted anti-tumor activity, was encapsulated into redox-sensitive shell crosslinked micelles to achieve intracellular targeted delivery and finally inhibit tumor growth and metastasis. The crosslinked micelles demonstrated good stability in circulation and specifically released DSF under a reductive environment that mimicked the intracellular conditions of tumor cells. As a result, the DSF-loaded redox-sensitive shell crosslinked micelles (DCMs) dramatically inhibited cell proliferation, induced cell apoptosis and suppressed cell invasion, as well as impairing tube formation of HMEC-1 cells. In addition, the DCMs could accumulate in tumor tissue and stay there for a long time, thereby causing significant inhibition of 4T1 tumor growth and marked prevention in lung metastasis of 4T1 tumors. These results suggested that DCMs could be a promising delivery system in inhibiting the growth and metastasis of breast cancer.

  19. Endophytic bacteria improve seedling growth of sunflower under water stress, produce salicylic acid, and inhibit growth of pathogenic fungi.

    PubMed

    Forchetti, Gabriela; Masciarelli, Oscar; Izaguirre, María J; Alemano, Sergio; Alvarez, Daniel; Abdala, Guillermina

    2010-12-01

    Endophytic bacterial strains SF2 (99.9% homology with Achromobacter xylosoxidans), and SF3 and SF4 (99.9% homology with Bacillus pumilus) isolated from sunflower grown under irrigation or drought were selected on the basis of plant growth-promoting bacteria (PGPB) characteristics. Aims of the study were to examine effects of inoculation with SF2, SF3, and SF4 on sunflower cultivated under water stress, to evaluate salicylic acid (SA) production by these strains in control medium or at Ψa = -2.03 MPa, and to analyze effects of exogenously applied SA, jasmonic acid (JA), bacterial pellets, and bacterial supernatants on growth of pathogenic fungi Alternaria sp., Sclerotinia sp., and Verticillum sp. Growth response to bacterial inoculation was studied in two inbred lines (water stress-sensitive B59 and water stress-tolerant B71) and commercial hybrid Paraiso 24. Under both water stress and normal conditions, plant growth following inoculation was more strongly enhanced for Paraiso 24 and B71 than for B59. All three strains produced SA in control medium; levels for SF3 and SF4 were higher than for SF2. SA production was dramatically higher at Ψa = -2.03 MPa. Exogenously applied SA or JA caused a significant reduction of growth for Sclerotinia and a lesser reduction for Alternaria and Verticillum. Fungal growth was more strongly inhibited by bacterial pellets than by bacterial supernatants. Our findings indicate that these endophytic bacteria enhance growth of sunflower seedlings under water stress, produce SA, and inhibit growth of pathogenic fungi. These characteristics are useful for formulation of inoculants to improve growth and yield of sunflower crops.

  20. CH5137291, an androgen receptor nuclear translocation-inhibiting compound, inhibits the growth of castration-resistant prostate cancer cells.

    PubMed

    Ishikura, Nobuyuki; Kawata, Hiromitsu; Nishimoto, Ayako; Nakamura, Ryo; Tsunenari, Toshiaki; Watanabe, Miho; Tachibana, Kazutaka; Shiraishi, Takuya; Yoshino, Hitoshi; Honma, Akie; Emura, Takashi; Ohta, Masateru; Nakagawa, Toshito; Houjo, Takao; Corey, Eva; Vessella, Robert L; Aoki, Yuko; Sato, Haruhiko

    2015-04-01

    Resistance of prostate cancer to castration is currently an unavoidable problem. The major mechanisms underlying such resistance are androgen receptor (AR) overexpression, androgen-independent activation of AR, and AR mutation. To address this problem, we developed an AR pure antagonist, CH5137291, with AR nuclear translocation-inhibiting activity, and compared its activity and characteristics with that of bicalutamide. Cell lines corresponding to the mechanisms of castration resistance were used: LNCaP-BC2 having AR overexpression and LNCaP-CS10 having androgen-independent AR activation. VCaP and LNCaP were used as hormone-sensitive prostate cancer cells. In vitro functional assay clearly showed that CH5137291 inhibited the nuclear translocation of wild-type ARs as well as W741C- and T877A-mutant ARs. In addition, it acted as a pure antagonist on the transcriptional activity of these types of ARs. In contrast, bicalutamide did not inhibit the nuclear translocation of these ARs, and showed a partial/full agonistic effect on the transcriptional activity. CH5137291 inhibited cell growth more strongly than bicalutamide in VCaP and LNCaP cells as well as in LNCaP-BC2 and LNCaP-CS10 cells in vitro. In xenograft models, CH5137291 strongly inhibited the tumor growth of LNCaP, LNCaP-BC2, and LNCaP-CS10, whereas bicalutamide showed a weaker effect in LNCaP and almost no effect in LNCaP-BC2 and LNCaP-CS10 xenografts. Levels of prostate-specific antigen (PSA) in plasma correlated well with the antitumor effect of both agents. CH5137291 inhibited the growth of LNCaP tumors that had become resistant to bicalutamide treatment. A docking model suggested that CH5137291 intensively collided with the M895 residue of helix 12, and therefore strongly inhibited the folding of helix 12, a cause of AR agonist activity, in wild-type and W741C-mutant ARs. In cynomolgus monkeys, the serum concentration of CH5137291 increased dose-dependently and PSA level decreased 80% at 100 mg/kg. CH

  1. Hugl-1 inhibits glioma cell growth in intracranial model.

    PubMed

    Liu, Xuejiao; Lu, Dong; Ma, Peng; Liu, Huaqiang; Cao, Yuewen; Sang, Ben; Zhu, Xianlong; Shi, Qiong; Hu, Jinxia; Yu, Rutong; Zhou, Xiuping

    2015-10-01

    Drosophila lethal (2) giant larvae (lgl) has been reported as a tumor suppressor and could regulate the Drosophila hippo signaling. Human giant larvae-1(Hugl-1), one human homologue of Drosophila lgl, also has been reported to be involved in the development of some human cancers. However, whether Hugl-1 is associated with the pathogenesis of malignant gliomas remains poorly understood. In the present work, we examined the effect of Hugl-1 on glioma cell growth both in vitro and in vivo. Firstly, we found that Hugl-1 protein levels decreased in the human glioma tissues, suggesting that Hugl-1 is involved in glioma progression. Unfortunately, either stably or transiently over-expressing Hugl-1 did not affect glioma cell proliferation in vitro. In addition, Hugl-1 over-expression did not regulate hippo signaling pathway. Interestingly, over-expression of Hugl-1 not only inhibited gliomagenesis but also markedly inhibited cell proliferation and promoted the apoptosis of U251 cells in an orthotopic model of nude mice. Taken together, this study provides the evidence that Hugl-1 inhibits glioma cell growth in intracranial model of nude mice, suggesting that Hugl-1 might be a potential tumor target for glioma therapy.

  2. Cell growth inhibition by sequence-specific RNA minihelices.

    PubMed Central

    Hipps, D; Schimmel, P

    1995-01-01

    RNA minihelices which reconstruct the 12 base pair acceptor-T psi C domains of transfer RNAs interact with their cognate tRNA synthetases. These substrates lack the anticodons of the genetic code and, therefore, cannot participate in steps of protein synthesis subsequent to aminoacylation. We report here that expression in Escherichia coli of either of two minihelices, each specific for a different amino acid, inhibited cell growth. Inhibition appears to be due to direct competition between the minihelix and its related tRNA for binding to their common synthetase. This competition, in turn, sharply lowers the pool of the specific charged tRNA for protein synthesis. Inhibition is relieved by single nucleotide changes which disrupt the minihelix-synthetase interaction. The results suggest that sequence-specific RNA minihelix substrates bind to cognate synthetases in vivo and can, in principle, act as cell growth regulators. Naturally occurring non-tRNA substrates for aminoacylation may serve a similar purpose. Images PMID:7664744

  3. Phytotoxicity of nanoparticles: inhibition of seed germination and root growth.

    PubMed

    Lin, Daohui; Xing, Baoshan

    2007-11-01

    Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC50) of nano-Zn and nano-ZnO were estimated to be near 50mg/L for radish, and about 20mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles.

  4. Colloidal Aggregation Causes Inhibition of G Protein-Coupled Receptors

    PubMed Central

    2013-01-01

    Colloidal aggregation is the dominant mechanism for artifactual inhibition of soluble proteins, and controls against it are now widely deployed. Conversely, investigating this mechanism for membrane-bound receptors has proven difficult. Here we investigate the activity of four well-characterized aggregators against three G protein-coupled receptors (GPCRs) recognizing peptide and protein ligands. Each of the aggregators was active at micromolar concentrations against the three GPCRs in cell-based assays. This activity could be attenuated by either centrifugation of the inhibitor stock solution or by addition of Tween-80 detergent. In the absence of agonist, the aggregators acted as inverse agonists, consistent with a direct receptor interaction. Meanwhile, several literature GPCR ligands that resemble aggregators themselves formed colloids, by both physical and enzymological tests. These observations suggest that some GPCRs may be artifactually antagonized by colloidal aggregates, an effect that merits the attention of investigators in this field. PMID:23437772

  5. Di (2-ethylhexyl) phthalate inhibits growth of mouse ovarian antral follicles through an oxidative stress pathway

    SciTech Connect

    Wang, Wei Craig, Zelieann R. Basavarajappa, Mallikarjuna S. Gupta, Rupesh K. Flaws, Jodi A.

    2012-01-15

    Di (2-ethylhexyl) phthalate (DEHP) is a plasticizer that has been shown to inhibit growth of mouse antral follicles, however, little is known about the mechanisms by which DEHP does so. Oxidative stress has been linked to follicle growth inhibition as well as phthalate-induced toxicity in non-ovarian tissues. Thus, we hypothesized that DEHP causes oxidative stress and that this leads to inhibition of the growth of antral follicles. To test this hypothesis, antral follicles isolated from CD-1 mice (age 31–35 days) were cultured with vehicle control (dimethylsulfoxide [DMSO]) or DEHP (1–100 μg/ml) ± N-acetyl cysteine (NAC, an antioxidant at 0.25–1 mM). During culture, follicles were measured daily. At the end of culture, follicles were collected and processed for in vitro reactive oxygen species (ROS) assays to measure the presence of free radicals or for measurement of the expression and activity of various key antioxidant enzymes: Cu/Zn superoxide dismutase (SOD1), glutathione peroxidase (GPX) and catalase (CAT). The results indicate that DEHP inhibits the growth of follicles compared to DMSO control and that NAC (0.25–1 mM) blocks the ability of DEHP to inhibit follicle growth. Furthermore, DEHP (10 μg/ml) significantly increases ROS levels and reduces the expression and activity of SOD1 compared to DMSO controls, whereas NAC (0.5 mM) rescues the effects of DEHP on ROS levels and SOD1. However, the expression and activity of GPX and CAT were not affected by DEHP treatment. Collectively, these data suggest that DEHP inhibits follicle growth by inducing production of ROS and by decreasing the expression and activity of SOD1. -- Highlights: ► DEHP inhibits growth and increases reactive oxygen species in ovarian antral follicles in vitro. ► NAC rescues the effects of DEHP on the growth and reactive oxygen species levels in follicles. ► DEHP decreases the expression and activity of Cu/Zn superoxide dismutase, which can be rescued by NAC, in antral

  6. Involvement of allelopathy in inhibition of understory growth in red pine forests.

    PubMed

    Kato-Noguchi, Hisashi; Kimura, Fukiko; Ohno, Osamu; Suenaga, Kiyotake

    2017-07-12

    Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests are characterized by sparse understory vegetation although sunlight intensity on the forest floor is sufficient for undergrowth. The possible involvement of pine allelopathy in the establishment of the sparse understory vegetation was investigated. The soil of the red pine forest floor had growth inhibitory activity on six test plant species including Lolium multiflorum, which was observed at the edge of the forest but not in the forest. Two growth inhibitory substances were isolated from the soil and characterized to be 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid. Those compounds are probably formed by degradation process of resin acids. Resin acids are produced by pine and delivered into the soil under the pine trees through balsam and defoliation. Threshold concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid for the growth inhibition of L. multiflorum were 30 and 10μM, respectively. The concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid in the soil were 312 and 397μM, respectively, which are sufficient concentrations to cause the growth inhibition because of the threshold. These results suggest that those compounds are able to work as allelopathic agents and may prevent from the invasion of herbaceous plants into the forests by inhibiting their growth. Therefore, allelopathy of red pine may be involved in the formation of the sparse understory vegetation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. Dephosphorylation is the mechanism of fibroblast growth factor inhibition of guanylyl cyclase-B.

    PubMed

    Robinson, Jerid W; Egbert, Jeremy R; Davydova, Julia; Schmidt, Hannes; Jaffe, Laurinda A; Potter, Lincoln R

    2017-09-28

    Activating mutations in fibroblast growth factor receptor 3 (FGFR3) and inactivating mutations of guanylyl cyclase-B (GC-B, also called NPRB or NPR2) cause dwarfism. FGF exposure inhibits GC-B activity in a chondrocyte cell line, but the mechanism of the inactivation is not known. Here, we report that FGF exposure causes dephosphorylation of GC-B in rat chondrosarcoma cells, which correlates with a rapid, potent and reversible inhibition of C-type natriuretic peptide-dependent activation of GC-B. Cells expressing a phosphomimetic mutant of GC-B that cannot be inactivated by dephosphorylation because it contains glutamate substitutions for all known phosphorylation sites showed no decrease in GC-B activity in response to FGF. We conclude that FGF rapidly inactivates GC-B by a reversible dephosphorylation mechanism, which may contribute to the signaling network by which activated FGFR3 causes dwarfism. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Pharmacologic inhibition of JAK-STAT signaling promotes hair growth.

    PubMed

    Harel, Sivan; Higgins, Claire A; Cerise, Jane E; Dai, Zhenpeng; Chen, James C; Clynes, Raphael; Christiano, Angela M

    2015-10-01

    Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells.

  9. Targeting Btk with ibrutinib inhibit gastric carcinoma cells growth

    PubMed Central

    Wang, Jin Dao; Chen, Xiao Ying; Ji, Ke Wei; Tao, Feng

    2016-01-01

    Bruton’s tyrosine kinase (Btk) is a member of the Tec-family non-receptor tyrosine kinases family. It has previously been reported to be expressed in B cells and has an important role in B-cell malignancies. While the roles of Btk in the pathogenesis of certain B-cell malignancies are well established, the functions of Btk in gastric carcinoma have never been investigated. Herein, we found that Btk is over-expressed in gastric carcinoma tissues and gastric cancer cells. Knockdown of Btk expression selectively inhibits the growth of gastric cancer cells, but not that of the normal gastric mucosa epithelial cell, which express very little Btk. Inhibition of Btk by its inhibitor ibrutinib has an additive inhibitory effect on gastric cancer cell growth. Treatment of gastric cancer cells, but not immortalized breast epithelial cells with ibrutinib results in effective cell killing, accompanied by the attenuation of Btk signals. Ibrutinib also induces apoptosis in gastric carcinoma cells as well as is a chemo-sensitizer for docetaxel (DTX), a standard of care for gastric carcinoma patients. Finally, ibrutinib markedly reduces tumor growth and increases tumor cell apoptosis in the tumors formed in mice inoculated with the gastric carcinoma cells. Given these promising preclinical results for ibrutinib in gastric carcinoma, a strategy combining Btk inhibitor warrants attention in gastric cancer. PMID:27508020

  10. Pharmacologic inhibition of JAK-STAT signaling promotes hair growth

    PubMed Central

    Harel, Sivan; Higgins, Claire A.; Cerise, Jane E.; Dai, Zhenpeng; Chen, James C.; Clynes, Raphael; Christiano, Angela M.

    2015-01-01

    Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells. PMID:26601320

  11. LIM kinase inhibition reduces breast cancer growth and invasiveness but systemic inhibition does not reduce metastasis in mice.

    PubMed

    Li, Rong; Doherty, Judy; Antonipillai, Juliana; Chen, Sheng; Devlin, Mark; Visser, Kathryn; Baell, Jonathan; Street, Ian; Anderson, Robin L; Bernard, Ora

    2013-04-01

    Metastasis is the major cause of morbidity and mortality in cancer patients. An understanding of the genes that regulate metastasis and development of therapies to target these genes is needed urgently. Since members of the LIM kinase (LIMK) family are key regulators of the actin cytoskeleton and are involved in cell motility and invasion, LIMK is considered to be a good therapeutic target for metastatic disease. Here we investigated the consequences of LIMK inhibition on growth and metastasis of human and mouse mammary tumors. LIMK activity was reduced in tumor cells by expression of dominant-negative LIMK1, by RNA interference or with a selective LIMK inhibitor. The extent of phosphorylation of the LIMK substrate, cofilin, of proliferation and invasion in 2D and 3D culture and of tumor growth and metastasis in mice were assessed. Inhibition of LIMK activity efficiently reduced the pro-invasive properties of tumor cells in vitro. Tumors expressing dominant-negative LIMK1 grew more slowly and were less metastatic in mice. However, systemic administration of a LIMK inhibitor did not reduce either primary tumor growth or spontaneous metastasis. Surprisingly, metastasis to the liver was increased after administration of the inhibitor. These data raise a concern about the use of systemic LIMK inhibitors for the treatment of metastatic breast cancer.

  12. Lovastatin inhibited the growth of gastric cancer cells.

    PubMed

    Cheng-Qian, Yang; Xin-Jing, Wei; Wei-Xinbing; Zhuang-Lei, Gao; Hong-Peng, Zhao; Songde, Xu; Pei-Lin, Wang

    2014-01-01

    Gastric cancer cells required large amount of cholesterol to grow and proliferate. The objective of this study was to examine whether the growth of gastric cancer cells was inhibited in vivo by using lovastatin, an effective cholesterol-lowing drug. The mice models for gastric cancer cells MKN45 were divided into two groups, the control and experimental group. Lovastatin was administered orally to the experimental group, while saline given to the control group. We measured the volume and weight of tumors, and calculated RTV (relative tumor volume), T/C (relative added value of tumor) and the inhibition rate. Then the expression levels of PCNA in gastric cancer tissues were examined immunohistochemically. The volume of tumors in the control and experimental groups was 3.801 +/- 1.078 and 3.325 +/- 0.745, respectively (p > 0.05), while RTV was 49.684 +/- 12.250 and 42.506 +/- 10.515, respectively (p > 0.05). T/C, an indication of antitumor, was 85.55%. The weight of tumors of the mice in control and experimental group was 3.23 +/- 0.43 and 2.65 +/- 0.58, respectively (p < 0.05). The inhibition rate was 20.48%. The PCNA index in the lovastatin group was 32.35 +/- 6.43%, while in the control group was 91.24 +/- 6.59%. The PCNA index of lovastatin group was much lower (P < 0.01). Lovastatin inhibited the growth of gastric cancer cells.

  13. The 'antimutagenic' effect of cinnamaldehyde is due to a transient growth inhibition.

    PubMed

    Rutten, B; Gocke, E

    1988-09-01

    Addition of cinnamaldehyde to the selective medium causes a reduction in the number of revertant colonies of S. typhimurium or E. coli when the cells have been mutagenized with 4NQO but not when they have been mutagenized with MNNG. Toxicity of the cinnamaldehyde exposure depends largely on the status of growth and/or nutrient supply of the cells. We present evidence that simple growth inhibition due to lack of nutrients mimics the effect of cinnamaldehyde in 4NQO- and MNNG-treated cells. This argues that the reduction of mutant colonies is due to a transient growth retardation caused by cinnamaldehyde exposure, which presumably allows the cells to repair 4NQO-induced damage--but not MNNG-induced damage--via a more error-free pathway.

  14. Feeding inhibition explains effects of imidacloprid on the growth, maturation, reproduction, and survival of Daphnia magna.

    PubMed

    Agatz, Annika; Cole, Tabatha A; Preuss, Thomas G; Zimmer, Elke; Brown, Colin D

    2013-03-19

    Effects of some xenobiotics on aquatic organisms might not be caused directly by the compound but rather arise from acclimation of the organism to stress invoked by feeding inhibition during exposure. Experiments were conducted to identify effects of imidacloprid on individual performance (feeding, growth, maturation, reproduction, and survival) of Daphnia magna under surplus and reduced food availability. Concentrations inhibiting feeding by 5, 50, and 95% after one day of exposure were 0.19, 1.83, and 8.70 mg/L, respectively. Exposure with imidacloprid at ≥ 3.7 mg/L reduced growth by up to 53 ± 11% within one week. Surplus food availability after inhibition allowed recovery from this growth inhibition, whereas limited food supply eliminated the potential for recovery in growth even for exposure at 0.15 mg/L. A shift in the distribution of individual energy reserves toward reproduction rather than growth resulted in increased reproduction after exposure to concentrations ≤ 0.4 mg/L. Exposure to imidacloprid at ≥ 4.0 mg/L overwhelmed this adaptive response and reduced reproduction by up to 57%. We used the individual based Daphnia magna population model IDamP as a virtual laboratory to demonstrate that only feeding was affected by imidacloprid, and that in turn this caused the other impacts on individual performance. Consideration of end points individually would have led to a different interpretation of the effects. Thus, we demonstrate how multiple lines of evidence linked by understanding the ecology of the organism are necessary to elucidate xenobiotic impacts along the effect cascade.

  15. The Thioamides Methimazole and Thiourea Inhibit Growth of M. avium Subspecies paratuberculosis in Culture

    PubMed Central

    Greenstein, Robert J.; Su, Liya; Brown, Sheldon T.

    2010-01-01

    Background Thyrotoxicosis is conceptualized as an “autoimmune” disease with no accepted infectious etiology. There are increasingly compelling data that another “autoimmune” affliction, Crohn disease, may be caused by Mycobacterium avium subspecies paratuberculosis (MAP). Like M. tb, MAP is systemic. We hypothesized that some cases of thyrotoxicosis may be initiated by a MAP infection. Because other thioamides treat tuberculosis, leprosy and M. avium complex, we hypothesized that a mode of action of some thioamide anti-thyrotoxicosis medications may include MAP growth inhibition. Methods The effect of the thioamides, thiourea, methimazole and 6-propo-2-thiouracil (6-PTU) were studied in radiometric Bactec® culture, on ten strains of three mycobacterial species (six of MAP, two of M. avium and two of M. tb. complex). Data are presented as “cumulative growth index,” (cGI) or “percent decrease in cumulative GI” (%-ΔcGI). Principal Findings Methimazole was the most effective thioamide at inhibiting MAP growth. At 128µg/ml: MAP UCF-4; 65%-ΔcGI & MAP ATCC 19698; 90%-ΔcGI. Thiourea inhibited MAP “Ben” maximally; 70%-ΔcGI. Neither methimazole nor thiourea inhibited M. avium or M. tb. at the doses tested. 6-PTU has no inhibition on any strain studied, although a structurally analogous control, 5-PTU, was the most inhibitory thioamide tested. Significance We show inhibition of MAP growth by the thioamides, thiourea and methimazole in culture. These data are compatible with the hypothesis that these thioamides may have anti-prokaryotic in addition to their well-established eukaryotic actions in thyrotoxic individuals. PMID:20559419

  16. Genetically enhanced growth causes increased mortality in hypoxic environments.

    PubMed

    Sundt-Hansen, L; Sundström, L F; Einum, S; Hindar, K; Fleming, I A; Devlin, R H

    2007-04-22

    Rapid growth and development are associated with several fitness-related benefits. Yet, organisms usually grow more slowly than their physiological maximum, suggesting that rapid growth may carry costs. Here we use coho salmon (Oncorhynchus kisutch) eggs of wild and transgenic genotypes to test whether rapid growth causes reduced tolerance to low levels of oxygen (hypoxia). Eggs were exposed to four different durations of hypoxia, and survival and growth were recorded until the end of the larval stage. Survival rates decreased with increasing duration of hypoxia, but this decrease was most pronounced for the transgenic group. Larval mass was also negatively affected by hypoxia; however, transgenic genotypes were significantly larger than wild genotypes at the end of the larval stage. Oxygen can be a limiting factor for survival and development in a wide range of organisms, particularly during the egg stage. Thus, the reduced ability of fast-growing genotypes to cope with low oxygen levels identified in the present study may represent a general constraint on evolution of rapid growth across taxa.

  17. Catechin-incorporated dental copolymers inhibit growth of Streptococcus mutans

    PubMed Central

    MANKOVSKAIA, Alexandra; LÉVESQUE, Céline M.; PRAKKI, Anuradha

    2013-01-01

    Objective: To test the inhibitory growth activity of green tea catechin incorporated into dental resins compared to resins containing the broad-spectrum antimicrobial compound chlorhexidine against Streptococcus mutans in vitro. Material and Methods: The minimum inhibitory concentrations (MICs) of epigallocatechin-gallate (EGCg) and chlorhexidine (CHX) were determined according to the microdilution method. Resin discs (5 mm x 3 mm) were prepared from Bis-GMA/TEGDMA (R1) and Bis-GMA/CH3Bis-GMA (R2) comonomers (n=9) containing: a) no drug, b) EGCg, c) CHX. Two concentrations of each drug (0.5x MIC and 1x MIC) were incorporated into the resin discs. Samples were individually immersed in a bacterial culture and incubated for 24 h at 37º C under constant agitation. Cell viability was assessed by counting the number of colonies on replica agar plates. Statistical analysis was performed using one-way ANOVA, Tukey and Student t-tests (α=0.05). Results: Both resins containing EGCg and CHX showed a significant inhibition of bacterial growth at both concentrations tested (p<0.05). A significantly higher inhibition was observed in response to resins containing CHX at 0.5x MIC and 1x MIC, and EGCg at 1x MIC when compared to EGCg at 0.5x MIC. Also, EGCg at 0.5x MIC in R1 had a significantly higher growth inhibition than in R2. Conclusions: Both EGCg and CHX retained their antibacterial activity when incorporated into the resin matrix. EGCg at 1x MIC in R1 and R2 resins significantly reduced S. mutans survival at a level similar to CHX. The data generated from this study will provide advances in the field of bioactive dental materials with the potential of improving the lifespan of resin-based restorations. PMID:23739855

  18. Inhibition of transforming growth factor β signaling promotes epiblast formation in mouse embryos.

    PubMed

    Ghimire, Sabitri; Heindryckx, Björn; Van der Jeught, Margot; Neupane, Jitesh; O'Leary, Thomas; Lierman, Sylvie; De Vos, Winnok H; Chuva de Sousa Lopes, Susana; Deroo, Tom; De Sutter, Petra

    2015-02-15

    Early lineage segregation in preimplantation embryos and maintenance of pluripotency in embryonic stem cells (ESCs) are both regulated by specific signaling pathways. Small molecules have been shown to modulate these signaling pathways. We examined the influence of several small molecules and growth factors on second-lineage segregation of the inner cell mass toward hypoblast and epiblast lineage during mouse embryonic preimplantation development. We found that the second-lineage segregation is influenced by activation or inhibition of the transforming growth factor (TGF)β pathway. Inhibition of the TGFβ pathway from the two-cell, four-cell, and morula stages onward up to the blastocyst stage significantly increased the epiblast cell proliferation. The epiblast formed in the embryos in which TGFβ signaling was inhibited was fully functional as demonstrated by the potential of these epiblast cells to give rise to pluripotent ESCs. Conversely, activating the TGFβ pathway reduced epiblast formation. Inhibition of the glycogen synthase kinase (GSK)3 pathway and activation of bone morphogenetic protein 4 signaling reduced the formation of both epiblast and hypoblast cells. Activation of the protein kinase A pathway and of the Janus kinase/signal transducer and activator of transcription 3 pathway did not influence the second-lineage segregation in mouse embryos. The simultaneous inhibition of three pathways--TGFβ, GSK3β, and the fibroblast growth factor (FGF)/extracellular signal-regulated kinases (Erk)--significantly enhanced the proliferation of epiblast cells than that caused by inhibition of either TGFβ pathway alone or by combined inhibition of the GSK3β and FGF/Erk pathways only.

  19. Statistical inference for tumor growth inhibition T/C ratio.

    PubMed

    Wu, Jianrong

    2010-09-01

    The tumor growth inhibition T/C ratio is commonly used to quantify treatment effects in drug screening tumor xenograft experiments. The T/C ratio is converted to an antitumor activity rating using an arbitrary cutoff point and often without any formal statistical inference. Here, we applied a nonparametric bootstrap method and a small sample likelihood ratio statistic to make a statistical inference of the T/C ratio, including both hypothesis testing and a confidence interval estimate. Furthermore, sample size and power are also discussed for statistical design of tumor xenograft experiments. Tumor xenograft data from an actual experiment were analyzed to illustrate the application.

  20. Clopidogrel inhibits angiogenesis of gastric ulcer healing via downregulation of vascular endothelial growth factor receptor 2.

    PubMed

    Luo, Jiing-Chyuan; Peng, Yen-Ling; Chen, Tseng-Shing; Huo, Teh-Ia; Hou, Ming-Chih; Huang, Hui-Chun; Lin, Han-Chieh; Lee, Fa-Yauh

    2016-09-01

    Although clopidogrel does not cause gastric mucosal injury, it does not prevent peptic ulcer recurrence in high-risk patients. We explored whether clopidogrel delays gastric ulcer healing via inhibiting angiogenesis and to elucidate the possible mechanisms. Gastric ulcers were induced in Sprague Dawley rats, and ulcer healing and angiogenesis of ulcer margin were compared between clopidogrel-treated rats and controls. The expressions of the proangiogenic growth factors and their receptors including basic fibroblast growth factor (bFGF), bFGF receptor (FGFR), vascular endothelial growth factor (VEGF), VEGFR1, VEGFR2, platelet-derived growth factor (PDGF)A, PDGFB, PDGFR A, PDGFR B, and phosphorylated form of mitogenic activated protein kinase pathways over the ulcer margin were compared via western blot and reverse transcription polymerase chain reaction. In vitro, human umbilical vein endothelial cells (HUVECs) were used to elucidate how clopidogrel inhibited growth factors-stimulated HUVEC proliferation. The ulcer sizes were significantly larger and the angiogenesis of ulcer margin was significantly diminished in the clopidogrel (2 and 10 mg/kg/d) treated groups. Ulcer induction markedly increased the expression of phosphorylated form of extracellular signal-regulated kinase (pERK), FGFR2, VEGF, VEGFR2, and PDGFRA when compared with those of normal mucosa. Clopidogrel treatment significantly decreased pERK, FGFR2, VEGF, VEGFR2, and PDGFRA expression at the ulcer margin when compared with those of the respective control group. In vitro, clopidogrel (10(-6)M) inhibited VEGF-stimulated (20 ng/mL) HUVEC proliferation, at least, via downregulation of VEGFR2 and pERK. Clopidogrel inhibits the angiogenesis of gastric ulcer healing at least partially by the inhibition of the VEGF-VEGFR2-ERK signal transduction pathway. Copyright © 2015. Published by Elsevier B.V.

  1. Slow and sustained nitric oxide releasing compounds inhibit multipotent vascular stem cell proliferation and differentiation without causing cell death

    SciTech Connect

    Curtis, Brandon M.; Leix, Kyle Alexander; Ji, Yajing; Glaves, Richard Samuel Elliot; Ash, David E.; Mohanty, Dillip K.

    2014-07-18

    Highlights: • Multipotent vascular stem cells (MVSCs) proliferate and differentiate. • Nitric oxide inhibits proliferation of MVSCs. • Nitric oxide inhibits MVSC differentiation to mesenchymal-like stem cells (MSCs). • Smooth muscle cells (SMCs) neither de-differentiate nor proliferate. - Abstract: Atherosclerosis is the leading cause of cerebral and myocardial infarction. It is believed that neointimal growth common in the later stages of atherosclerosis is a result of vascular smooth muscle cell (SMC) de-differentiation in response to endothelial injury. However, the claims of the SMC de-differentiation theory have not been substantiated by monitoring the fate of mature SMCs in response to such injuries. A recent study suggests that atherosclerosis is a consequence of multipotent vascular stem cell (MVSC) differentiation. Nitric oxide (NO) is a well-known mediator against atherosclerosis, in part because of its inhibitory effect on SMC proliferation. Using three different NO-donors, we have investigated the effects of NO on MVSC proliferation. Results indicate that NO inhibits MVSC proliferation in a concentration dependent manner. A slow and sustained delivery of NO proved to inhibit proliferation without causing cell death. On the other hand, larger, single-burst NO concentrations, inhibits proliferation, with concurrent significant cell death. Furthermore, our results indicate that endogenously produced NO inhibits MVSC differentiation to mesenchymal-like stem cells (MSCs) and subsequently to SMC as well.

  2. Aerosolized 3-bromopyruvate inhibits lung tumorigenesis without causing liver toxicity.

    PubMed

    Zhang, Qi; Pan, Jing; North, Paula E; Yang, Shoua; Lubet, Ronald A; Wang, Yian; You, Ming

    2012-05-01

    3-Bromopyruvate, an alkylating agent and a well-known inhibitor of energy metabolism, has been proposed as a specific anticancer agent. However, the chemopreventive effect of 3-bromopyruvate in lung tumorigenesis has not been tested. In this study, we investigated the chemopreventive activity of 3-bromopyruvate in a mouse lung tumor model. Benzo(a)pyrene was used to induce lung tumors, and 3-bromopyruvate was administered by oral gavage to female A/J mice. We found that 3-bromopyruvate significantly decreased tumor multiplicity and tumor load by 58% and 83%, respectively, at a dose of 20 mg/kg body weight by gavage. Due to the known liver toxicity of 3-bromopyruvate in animal models given large doses of 3-bromopyruvate, confirmed in this study, we decided to test the chemopreventive activity of aerosolized 3-bromopyruvate in the same lung tumor model. As expected, aerosolized 3-bromopyruvate similarly significantly decreased tumor multiplicity and tumor load by 49% and 80%, respectively, at a dose of 10 mg/mL by inhalation. Interestingly, the efficacy of aerosolized 3-bromopyruvate did not accompany any liver toxicity indicating that it is a safer route of administering this compound. Treatment with 3-bromopyruvate increased immunohistochemical staining for cleaved caspase-3, suggesting that the lung tumor inhibitory effects of 3-bromopyruvate were through induction of apoptosis. 3-Bromopyruvate also dissociated hexokinase II from mitochondria, reduced hexokinase activity, and blocked energy metabolism in cancer cells, finally triggered cancer cell death and induced apoptosis through caspase-3, and PARP in human lung cancer cell line. The ability of 3-bromopyruvate to inhibit mouse lung tumorigenesis, in part through induction of apoptosis, merits further investigation of this compound as a chemopreventive agent for human lung cancer.

  3. Targeting GIPC/Synectin in Pancreatic Cancer Inhibits Tumor Growth

    PubMed Central

    Muders, Michael H.; Vohra, Pawan K.; Dutta, Shamit K; Wang, Enfeng; Ikeda, Yasuhiro; Wang, Ling; Udugamasooriya, D. Gomika; Memic, Adnan; Rupashinghe, Chamila N.; Baretton, Gustavo B.; Aust, Daniela E.; Langer, Silke; Datta, Kaustubh; Simons, Michael; Spaller, Mark R.; Mukhopadhyay, Debabrata

    2009-01-01

    Translational Relevance The five year survival rate in patients with ductal adenocarcinoma of the pancreas is less than 4%. Accordingly, new targets for the treatment of this deadly disease are urgently needed. In this study, we show that targeting GAIP interacting protein C-terminal (GIPC, also known as Synectin) and its PDZ-domain reduces pancreatic cancer growth significantly in vitro and in vivo. Additionally, the blockage of GIPC/Synectin was accompanied by a reduction of IGF-1R protein levels. In summary, the use of a GIPC-PDZ domain inhibitor may be a viable option in the treatment of pancreatic adenocarcinoma in future. Purpose Various studies have demonstrated the importance of GAIP interacting protein, C-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth promoting receptors like IGF-1R and integrins. These interactions were mediated through its PDZ domain. GIPC/Synectin has been shown to be overexpressed in pancreatic and breast cancer. The goal of this study was to demonstrate the importance of GIPC/Synectin in pancreatic cancer growth and to evaluate a possible therapeutic strategy by using a GIPC-PDZ domain inhibitor. Furthermore, the effect of targeting GIPC on the IGF-1 receptor as one of its associated receptors was tested. Experimental Design In vivo effects of GIPC/Synectin knockdown were studied after lentiviral transduction of luciferase-expressing pancreatic cancer cells with shRNA against GIPC/Synectin. Additionally, a GIPC-PDZ-targeting peptide was designed. This peptide was tested for its influence on pancreatic cancer growth in vitro and in vivo. Results Knockdown of GIPC/Synectin led to a significant inhibition of pancreatic adenocarcinoma growth in an orthotopic mouse model. Additionally, a cell-permeable GIPC-PDZ inhibitor was able to block tumor growth significantly without showing

  4. Piperlongumine inhibits lung tumor growth via inhibition of nuclear factor kappa B signaling pathway

    PubMed Central

    Zheng, Jie; Son, Dong Ju; Gu, Sun Mi; Woo, Ju Rang; Ham, Young Wan; Lee, Hee Pom; Kim, Wun Jae; Jung, Jae Kyung; Hong, Jin Tae

    2016-01-01

    Piperlongumine has anti-cancer activity in numerous cancer cell lines via various signaling pathways. But there has been no study regarding the mechanisms of PL on the lung cancer yet. Thus, we evaluated the anti-cancer effects and possible mechanisms of PL on non-small cell lung cancer (NSCLC) cells in vivo and in vitro. Our findings showed that PL induced apoptotic cell death and suppressed the DNA binding activity of NF-κB in a concentration dependent manner (0–15 μM) in NSCLC cells. Docking model and pull down assay showed that PL directly binds to the DNA binding site of nuclear factor-κB (NF-κB) p50 subunit, and surface plasmon resonance (SPR) analysis showed that PL binds to p50 concentration-dependently. Moreover, co-treatment of PL with NF-κB inhibitor phenylarsine oxide (0.1 μM) or p50 siRNA (100 nM) augmented PL-induced inhibitory effect on cell growth and activation of Fas and DR4. Notably, co-treatment of PL with p50 mutant plasmid (C62S) partially abolished PL-induced cell growth inhibition and decreased the enhanced expression of Fas and DR4. In xenograft mice model, PL (2.5–5 mg/kg) suppressed tumor growth of NSCLC dose-dependently. Therefore, these results indicated that PL could inhibit lung cancer cell growth via inhibition of NF-κB signaling pathway in vitro and in vivo. PMID:27198178

  5. FH535 inhibited migration and growth of breast cancer cells.

    PubMed

    Iida, Joji; Dorchak, Jesse; Lehman, John R; Clancy, Rebecca; Luo, Chunqing; Chen, Yaqin; Somiari, Stella; Ellsworth, Rachel E; Hu, Hai; Mural, Richard J; Shriver, Craig D

    2012-01-01

    There is substantial evidence indicating that the WNT signaling pathway is activated in various cancer cell types including breast cancer. Previous studies reported that FH535, a small molecule inhibitor of the WNT signaling pathway, decreased growth of cancer cells but not normal fibroblasts, suggesting this pathway plays a role in tumor progression and metastasis. In this study, we tested FH535 as a potential inhibitor for malignant phenotypes of breast cancer cells including migration, invasion, and growth. FH535 significantly inhibited growth, migration, and invasion of triple negative (TN) breast cancer cell lines (MDA-MB231 and HCC38) in vitro. We demonstrate that FH535 was a potent growth inhibitor for TN breast cancer cell lines (HCC38 and MDA-MB-231) but not for other, non-TN breast cancer cell lines (MCF-7, T47D or SK-Br3) when cultured in three dimensional (3D) type I collagen gels. Western blotting analyses suggest that treatment of MDA-MB-231 cells with FH535 markedly inhibited the expression of NEDD9 but not activations of FAK, Src, or downstream targets such as p38 and Erk1/2. We demonstrated that NEDD9 was specifically associated with CSPG4 but not with β1 integrin or CD44 in MDA-MB-231 cells. Analyses of gene expression profiles in breast cancer tissues suggest that CSPG4 expression is higher in Basal-type breast cancers, many of which are TN, than any other subtypes. These results suggest not only a mechanism for migration and invasion involving the canonical WNT-signaling pathways but also novel strategies for treating patients who develop TN breast cancer.

  6. Mo polyoxometalate nanoparticles inhibit tumor growth and vascular endothelial growth factor induced angiogenesis

    NASA Astrophysics Data System (ADS)

    Zheng, Wenjing; Yang, Licong; Liu, Ying; Qin, Xiuying; Zhou, Yanhui; Zhou, Yunshan; Liu, Jie

    2014-06-01

    Tumor growth depends on angiogenesis, which can furnish the oxygen and nutrients that proliferate tumor cells. Thus, blocking angiogenesis can be an effective strategy to inhibit tumor growth. In this work, three typical nanoparticles based on polyoxometalates (POMs) have been prepared; we investigated their capability as antitumor and anti-angiogenesis agents. We found that Mo POM nanoparticles, especially complex 3, inhibited the growth of human hepatocellular liver carcinoma cells (HepG2) through cellular reactive oxygen species levels’ elevation and mitochondrial membrane potential damage. Complex 3 also suppressed the proliferation, migration, and tube formation of endothelial cells in vitro and chicken chorioallantoic membrane development ex vivo. Furthermore, western blot analysis of cell signaling molecules indicated that Mo POMs blocked the vascular endothelial growth factor receptor 2-mediated ERK1/2 and AKT signaling pathways in endothelial cells. Using transmission electron microscopy, we demonstrated their cellular uptake and localization within the cytoplasm of HepG2 cells. These results indicate that, owing to the extraordinary physical and chemical properties, Mo POM nanoparticles can significantly inhibit tumor growth and angiogenesis, which makes them potential drug candidates in anticancer and anti-angiogenesis therapies.

  7. Pu-erh Tea Inhibits Tumor Cell Growth by Down-Regulating Mutant p53

    PubMed Central

    Zhao, Lanjun; Jia, Shuting; Tang, Wenru; Sheng, Jun; Luo, Ying

    2011-01-01

    Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms’ metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects. PMID:22174618

  8. Pu-erh tea inhibits tumor cell growth by down-regulating mutant p53.

    PubMed

    Zhao, Lanjun; Jia, Shuting; Tang, Wenru; Sheng, Jun; Luo, Ying

    2011-01-01

    Pu-erh tea is a kind of fermented tea with the incorporation of microorganisms' metabolites. Unlike green tea, the chemical characteristics and bioactivities of Pu-erh tea are still not well understood. Using water extracts of Pu-erh tea, we analyzed the tumor cell growth inhibition activities on several genetically engineered mouse tumor cell lines. We found that at the concentration that did not affect wild type mouse embryo fibroblasts (MEFs) growth, Pu-erh tea extracts could inhibit tumor cell growth by down-regulated S phase and cause G1 or G2 arrest. Further study showed that Pu-erh tea extracts down-regulated the expression of mutant p53 in tumor cells at the protein level as well as mRNA level. The same concentration of Pu-erh tea solution did not cause p53 stabilization or activation of its downstream pathways in wild type cells. We also found that Pu-erh tea treatment could slightly down-regulate both HSP70 and HSP90 protein levels in tumor cells. These data revealed the action of Pu-erh tea on tumor cells and provided the possible mechanism for Pu-erh tea action, which explained its selectivity in inhibiting tumor cells without affecting wild type cells. Our data sheds light on the application of Pu-erh tea as an anti-tumor agent with low side effects.

  9. Cinnamic Acid Increases Lignin Production and Inhibits Soybean Root Growth

    PubMed Central

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth. PMID:23922685

  10. Herbicide glufosinate inhibits yeast growth and extends longevity during wine fermentation.

    PubMed

    Vallejo, Beatriz; Picazo, Cecilia; Orozco, Helena; Matallana, Emilia; Aranda, Agustín

    2017-09-29

    Glufosinate ammonium (GA) is a widely used herbicide that inhibits glutamine synthetase. This inhibition leads to internal amino acid starvation which, in turn, causes the activation of different nutrient sensing pathways. GA also inhibits the enzyme of the yeast Saccharomyces cerevisiae in such a way that, although it is not used as a fungicide, it may alter yeast performance in industrial processes like winemaking. We describe herein how GA indeed inhibits the yeast growth of a wine strain during the fermentation of grape juice. In turn, GA extends longevity in a variety of growth media. The biochemical analysis indicates that GA partially inhibits the nutrient sensing TORC1 pathway, which may explain these phenotypes. The GCN2 kinase mutant is hypersensitive to GA. Hence the control of translation and amino acid biosynthesis is required to also deal with the damaging effects of this pesticide. A global metabolomics analysis under winemaking conditions indicated that an increase in amino acid and in polyamines occurred. In conclusion, GA affects many different biochemical processes during winemaking, which provides us with some insights into both the effect of this herbicide on yeast physiology and into the relevance of the metabolic step for connecting nitrogen and carbon metabolism.

  11. Estrogen receptor beta inhibits angiogenesis and growth of T47D breast cancer xenografts.

    PubMed

    Hartman, Johan; Lindberg, Karolina; Morani, Andrea; Inzunza, José; Ström, Anders; Gustafsson, Jan-Ake

    2006-12-01

    Estrogens, which are stimulators of growth of both the normal breast and malignant breast, mediate their effects through two estrogen receptors (ER), namely ERalpha and ERbeta. ERalpha mediates the proliferative effect of estrogen in breast cancer cells, whereas ERbeta seems to be antiproliferative. We engineered ERalpha-positive T47D breast cancer cells to express ERbeta in a Tet-Off-regulated manner. These cells were then injected orthotopically into severe combined immunodeficient mice, and the growth of the resulting tumors was compared with tumors resulting from injecting the parental T47D cells that do not express ERbeta. The presence of ERbeta resulted in a reduction in tumor growth. Comparison of the ERbeta-expressing and non-ERbeta-expressing tumors revealed that the expression of ERbeta caused a reduction in the number of intratumoral blood vessels and a decrease in expression of the proangiogenic factors vascular endothelial growth factor (VEGF) and platelet-derived growth factor beta (PDGFbeta). In cell culture, with the Tet-Off-regulated ERbeta-expressing cells, expression of ERbeta decreased expression of VEGF and PDGFbeta mRNA under normoxic as well as hypoxic conditions and reduced secreted VEGF and PDGFbeta proteins in cell culture medium. Transient transfection assays with 1,026 bp VEGF and 1,006 bp PDGFbeta promoter constructs revealed a repressive effect of ERbeta at the promoter level of these genes. Taken together, these data show that introduction of ERbeta into malignant cells inhibits their growth and prevents tumor expansion by inhibiting angiogenesis.

  12. The inhibition of crystal growth of mirabilite in aqueous solutions in the presence of phosphonates

    NASA Astrophysics Data System (ADS)

    Vavouraki, A. I.; Koutsoukos, P. G.

    2016-02-01

    The formation of sodium sulfate decahydrate (Mirabilite) has been known to cause serious damages to structural materials both of modern and of historical buildings. Methods which can retard or completely suppress the development of mirabilte crystals are urgently needed especially as remedies or preventive measures for the preservation of the built cultural heritage. In the present work we present results on the effect of the presence of phosphonate compounds on the kinetics of crystal growth from aqueous supersaturated solutions at 18 °C using the seeded growth technique. The phosphonate compounds tested differed with respect to the number of ionizable phosphonate groups and with respect to the number of amino groups in the respective molecules. The crystal growth process was monitored by the temperature changes during the exothermic crystallization of mirabilite in the stirred supersaturated solutions. The crystal growth of mirabilite in the presence of: (1-hydroxyethylidene)-1, 1-diphosphonic acid (HEDP), amino tri (methylene phosphonic acid) (ATMP), hexamethylenediaminetetra (methylene)phosphonic acid (HTDMP), and diethylene triamine penta(methylene phosphonic acid)(DETPMP) over a range of concentrations between 0.1-5% w/w resulted in significant decrease of the rates of mirabilite crystal growth. All phosphonic compounds tested reduced the crystallization rates up to 60% in comparison with additive-free solutions. The presence of the test compounds did not cause changes of the mechanism of crystal growth which was surface diffusion controlled, as shown by the second order dependence of the rates of mirabilite crystal growth on the relative supersaturation. The excellent fit of the measured rates to a kinetic Langmuir-type model suggested that the activity of the tested inhibitors could be attributed to the adsorption and subsequent reduction of the active crystal growth sites of the seed crystals. In all cases, the inhibitory activity was reduced with

  13. Cancer growth and its inhibition in terms of coherence.

    PubMed

    Popp, Fritz-Albert

    2009-01-01

    It is shown that a molecular origin for growth inhibition is rather unlikely because the cross-sectional area of inhibitory forces in a cell population cannot exceed more than about 10(-8) Dalton. A model of the time dependence of cell number N(t), where t is the time, is based on biophotons and explains without any contradiction to known experimental results growth regulation in terms of the factor a = 1/T, which stimulates the cell division rate dN/dt and the factor b = dT/dN(1/T(2)), which inhibits cell division. It accounts for the total cell division rate dN/dt = aN(t) - bN(2)(t). For adults, T is the coherence time of about 10(6) s, corresponding to the longest lifetime of cell organelles in men, while dT/dN = 10(-7) s corresponds to the resolution time of the cell population which is always the average time interval between two cell loss events. Our model follows a stringently holistic approach to describing a cell population as an entity, regulated by a fully coherent (biophoton) field.

  14. Human astrocytes inhibit Cryptococcus neoformans growth by a nitric oxide-mediated mechanism

    PubMed Central

    1994-01-01

    Cryptococcus neoformans is an opportunistic fungus that causes life- threatening meningoencephalitis in 5-10% of patients with acquired immune deficiency syndrome. Cryptococcal meningoencephalitis is characterized by a lymphohistiocytic infiltrate, accumulation of encapsulated forms of C. neoformans, and varying degrees of glial reaction. Little is known about the contribution of endogenous central nervous system cells to the pathogenesis of cryptococcal infections. In this study, we investigated the role of astrocytes as potential effector cells against C. neoformans. Primary cultures of human fetal astrocytes, activated with interleukin 1 beta plus interferon gamma inhibited the growth of C. neoformans. The inhibition of C. neoformans growth was paralleled by production of nitrite, and reversed by the inhibitors of nitric oxide (NO.) synthase, NG-methyl-mono-arginine and NG-nitro-arginine methyl ester. The results suggest a novel function for human astrocytes in host defence and provide a precedent for the use of NO. as an antimicrobial effector molecule by human cells. PMID:8006595

  15. Deletion of Prepl Causes Growth Impairment and Hypotonia in Mice

    PubMed Central

    Lone, Anna Mari; Leidl, Mathias; McFedries, Amanda K.; Horner, James W.; Creemers, John; Saghatelian, Alan

    2014-01-01

    Genetic studies of rare diseases can identify genes of unknown function that strongly impact human physiology. Prolyl endopeptidase-like (PREPL) is an uncharacterized member of the prolyl peptidase family that was discovered because of its deletion in humans with hypotonia-cystinuria syndrome (HCS). HCS is characterized by a number of physiological changes including diminished growth and neonatal hypotonia or low muscle tone. HCS patients have deletions in other genes as well, making it difficult to tease apart the specific role of PREPL. Here, we develop a PREPL null (PREPL−/−) mouse model to address the physiological role of this enzyme. Deletion of exon 11 from the Prepl gene, which encodes key catalytic amino acids, leads to a loss of PREPL protein as well as lower Prepl mRNA levels. PREPL−/− mice have a pronounced growth phenotype, being significantly shorter and lighter than their wild type (PREPL+/+) counterparts. A righting assay revealed that PREPL−/− pups took significantly longer than PREPL+/+ pups to right themselves when placed on their backs. This deficit indicates that PREPL−/− mice suffer from neonatal hypotonia. According to these results, PREPL regulates growth and neonatal hypotonia in mice, which supports the idea that PREPL causes diminished growth and neonatal hypotonia in humans with HCS. These animals provide a valuable asset in deciphering the underlying biochemical, cellular and physiological pathways that link PREPL to HCS, and this may eventually lead to new insights in the treatment of this disease. PMID:24586561

  16. Glyphosate and AMPA inhibit cancer cell growth through inhibiting intracellular glycine synthesis

    PubMed Central

    Li, Qingli; Lambrechts, Mark J; Zhang, Qiuyang; Liu, Sen; Ge, Dongxia; Yin, Rutie; Xi, Mingrong; You, Zongbing

    2013-01-01

    Glycine is a nonessential amino acid that is reversibly converted from serine intracellularly by serine hydroxymethyltransferase. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), are analogs to glycine, thus they may inhibit serine hydroxymethyltransferase to decrease intracellular glycine synthesis. In this study, we found that glyphosate and AMPA inhibited cell growth in eight human cancer cell lines but not in two immortalized human normal prostatic epithelial cell lines. AMPA arrested C4-2B and PC-3 cancer cells in the G1/G0 phase and inhibited entry into the S phase of the cell cycle. AMPA also promoted apoptosis in C4-2B and PC-3 cancer cell lines. AMPA upregulated p53 and p21 protein levels as well as procaspase 9 protein levels in C4-2B cells, whereas it downregulated cyclin D3 protein levels. AMPA also activated caspase 3 and induced cleavage of poly (adenosine diphosphate [ADP]-ribose) polymerase. This study provides the first evidence that glyphosate and AMPA can inhibit proliferation and promote apoptosis of cancer cells but not normal cells, suggesting that they have potentials to be developed into a new anticancer therapy. PMID:23983455

  17. Piperine inhibits the growth and motility of triple-negative breast cancer cells.

    PubMed

    Greenshields, Anna L; Doucette, Carolyn D; Sutton, Kimberly M; Madera, Laurence; Annan, Henry; Yaffe, Paul B; Knickle, Allison F; Dong, Zhongmin; Hoskin, David W

    2015-02-01

    Piperine, an alkaloid from black pepper, is reported to have anticancer activities. In this study, we investigated the effect of piperine on the growth and motility of triple-negative breast cancer (TNBC) cells. Piperine inhibited the in vitro growth of TNBC cells, as well as hormone-dependent breast cancer cells, without affecting normal mammary epithelial cell growth. Exposure to piperine decreased the percentage of TNBC cells in the G2 phase of the cell cycle. In addition, G1- and G2-associated protein expression was decreased and p21(Waf1/Cip1) expression was increased in piperine-treated TNBC cells. Piperine also inhibited survival-promoting Akt activation in TNBC cells and caused caspase-dependent apoptosis via the mitochondrial pathway. Interestingly, combined treatment with piperine and γ radiation was more cytotoxic for TNBC cells than γ radiation alone. The in vitro migration of piperine-treated TNBC cells was impaired and expression of matrix metalloproteinase-2 and -9 mRNA was decreased, suggesting an antimetastatic effect by piperine. Finally, intratumoral administration of piperine inhibited the growth of TNBC xenografts in immune-deficient mice. Taken together, these findings suggest that piperine may be useful in the treatment of TNBC. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. PPARγ ligands inhibit primary tumor growth and metastasis by inhibiting angiogenesis

    PubMed Central

    Panigrahy, Dipak; Singer, Samuel; Shen, Lucy Q.; Butterfield, Catherine E.; Freedman, Deborah A.; Chen, Emy J.; Moses, Marsha A.; Kilroy, Susan; Duensing, Stefan; Fletcher, Christopher; Fletcher, Jonathan A.; Hlatky, Lynn; Hahnfeldt, Philip; Folkman, Judah; Kaipainen, Arja

    2002-01-01

    Several drugs approved for a variety of indications have been shown to exhibit antiangiogenic effects. Our study focuses on the PPARγ ligand rosiglitazone, a compound widely used in the treatment of type 2 diabetes. We demonstrate, for the first time to our knowledge, that PPARγ is highly expressed in tumor endothelium and is activated by rosiglitazone in cultured endothelial cells. Furthermore, we show that rosiglitazone suppresses primary tumor growth and metastasis by both direct and indirect antiangiogenic effects. Rosiglitazone inhibits bovine capillary endothelial cell but not tumor cell proliferation at low doses in vitro and decreases VEGF production by tumor cells. In our in vivo studies, rosiglitazone suppresses angiogenesis in the chick chorioallantoic membrane, in the avascular cornea, and in a variety of primary tumors. These results suggest that PPARγ ligands may be useful in treating angiogenic diseases such as cancer by inhibiting angiogenesis. PMID:12370270

  19. Simultaneous Assessment of Acidogenesis-Mitigation and Specific Bacterial Growth-Inhibition by Dentifrices

    PubMed Central

    Forbes, Sarah; Latimer, Joe; Sreenivasan, Prem K.; McBain, Andrew J.

    2016-01-01

    Dentifrices can augment oral hygiene by inactivating bacteria and at sub-lethal concentrations may affect bacterial metabolism, potentially inhibiting acidogenesis, the main cause of caries. Reported herein is the development of a rapid method to simultaneously measure group-specific bactericidal and acidogenesis-mitigation effects of dentifrices on oral bacteria. Saliva was incubated aerobically and anaerobically in Tryptone Soya Broth, Wilkins-Chalgren Broth with mucin, or artificial saliva and was exposed to dentifrices containing triclosan/copolymer (TD); sodium fluoride (FD); stannous fluoride and zinc lactate (SFD1); or stannous fluoride, zinc lactate and stannous chloride (SFD2). Minimum inhibitory concentrations (MIC) were determined turbidometrically whilst group-specific minimum bactericidal concentrations (MBC) were assessed using growth media and conditions selective for total aerobes, total anaerobes, streptococci and Gram-negative anaerobes. Minimum acid neutralization concentration (MNC) was defined as the lowest concentration of dentifrice at which acidification was inhibited. Differences between MIC and MNC were calculated and normalized with respect to MIC to derive the combined inhibitory and neutralizing capacity (CINC), a cumulative measure of acidogenesis-mitigation and growth inhibition. The overall rank order for growth inhibition potency (MIC) under aerobic and anaerobic conditions was: TD> SFD2> SFD1> FD. Acidogenesis-mitigation (MNC) was ordered; TD> FD> SFD2> SFD1. CINC was ordered TD> FD> SFD2> SFD1 aerobically and TD> FD> SFD1> SFD2 anaerobically. With respect to group-specific bactericidal activity, TD generally exhibited the greatest potency, particularly against total aerobes, total anaerobes and streptococci. This approach enables the rapid simultaneous evaluation of acidity mitigation, growth inhibition and specific antimicrobial activity by dentifrices. PMID:26882309

  20. Simultaneous Assessment of Acidogenesis-Mitigation and Specific Bacterial Growth-Inhibition by Dentifrices.

    PubMed

    Forbes, Sarah; Latimer, Joe; Sreenivasan, Prem K; McBain, Andrew J

    2016-01-01

    Dentifrices can augment oral hygiene by inactivating bacteria and at sub-lethal concentrations may affect bacterial metabolism, potentially inhibiting acidogenesis, the main cause of caries. Reported herein is the development of a rapid method to simultaneously measure group-specific bactericidal and acidogenesis-mitigation effects of dentifrices on oral bacteria. Saliva was incubated aerobically and anaerobically in Tryptone Soya Broth, Wilkins-Chalgren Broth with mucin, or artificial saliva and was exposed to dentifrices containing triclosan/copolymer (TD); sodium fluoride (FD); stannous fluoride and zinc lactate (SFD1); or stannous fluoride, zinc lactate and stannous chloride (SFD2). Minimum inhibitory concentrations (MIC) were determined turbidometrically whilst group-specific minimum bactericidal concentrations (MBC) were assessed using growth media and conditions selective for total aerobes, total anaerobes, streptococci and Gram-negative anaerobes. Minimum acid neutralization concentration (MNC) was defined as the lowest concentration of dentifrice at which acidification was inhibited. Differences between MIC and MNC were calculated and normalized with respect to MIC to derive the combined inhibitory and neutralizing capacity (CINC), a cumulative measure of acidogenesis-mitigation and growth inhibition. The overall rank order for growth inhibition potency (MIC) under aerobic and anaerobic conditions was: TD> SFD2> SFD1> FD. Acidogenesis-mitigation (MNC) was ordered; TD> FD> SFD2> SFD1. CINC was ordered TD> FD> SFD2> SFD1 aerobically and TD> FD> SFD1> SFD2 anaerobically. With respect to group-specific bactericidal activity, TD generally exhibited the greatest potency, particularly against total aerobes, total anaerobes and streptococci. This approach enables the rapid simultaneous evaluation of acidity mitigation, growth inhibition and specific antimicrobial activity by dentifrices.

  1. Dynamic light scattering study of inhibition of nucleation and growth of hydroxyapatite crystals by osteopontin.

    PubMed

    de Bruyn, John R; Goiko, Maria; Mozaffari, Maryam; Bator, Daniel; Dauphinee, Ron L; Liao, Yinyin; Flemming, Roberta L; Bramble, Michael S; Hunter, Graeme K; Goldberg, Harvey A

    2013-01-01

    We study the effect of isoforms of osteopontin (OPN) on the nucleation and growth of crystals from a supersaturated solution of calcium and phosphate ions. Dynamic light scattering is used to monitor the size of the precipitating particles and to provide information about their concentration. At the ion concentrations studied, immediate precipitation was observed in control experiments with no osteopontin in the solution, and the size of the precipitating particles increased steadily with time. The precipitate was identified as hydroxyapatite by X-ray diffraction. Addition of native osteopontin (nOPN) extracted from rat bone caused a delay in the onset of precipitation and reduced the number of particles that formed, but the few particles that did form grew to a larger size than in the absence of the protein. Recombinant osteopontin (rOPN), which lacks phosphorylation, caused no delay in initial calcium phosphate precipitation but severely slowed crystal growth, suggesting that rOPN inhibits growth but not nucleation. rOPN treated with protein kinase CK2 to phosphorylate the molecule (p-rOPN) produced an effect similar to that of nOPN, but at higher protein concentrations and to a lesser extent. These results suggest that phosphorylations are critical to OPN's ability to inhibit nucleation, whereas the growth of the hydroxyapatite crystals is effectively controlled by the highly acidic OPN polypeptide. This work also demonstrates that dynamic light scattering can be a powerful tool for delineating the mechanism of protein modulation of mineral formation.

  2. Dynamic Light Scattering Study of Inhibition of Nucleation and Growth of Hydroxyapatite Crystals by Osteopontin

    PubMed Central

    de Bruyn, John R.; Goiko, Maria; Mozaffari, Maryam; Bator, Daniel; Dauphinee, Ron L.; Liao, Yinyin; Flemming, Roberta L.; Bramble, Michael S.; Hunter, Graeme K.; Goldberg, Harvey A.

    2013-01-01

    We study the effect of isoforms of osteopontin (OPN) on the nucleation and growth of crystals from a supersaturated solution of calcium and phosphate ions. Dynamic light scattering is used to monitor the size of the precipitating particles and to provide information about their concentration. At the ion concentrations studied, immediate precipitation was observed in control experiments with no osteopontin in the solution, and the size of the precipitating particles increased steadily with time. The precipitate was identified as hydroxyapatite by X-ray diffraction. Addition of native osteopontin (nOPN) extracted from rat bone caused a delay in the onset of precipitation and reduced the number of particles that formed, but the few particles that did form grew to a larger size than in the absence of the protein. Recombinant osteopontin (rOPN), which lacks phosphorylation, caused no delay in initial calcium phosphate precipitation but severely slowed crystal growth, suggesting that rOPN inhibits growth but not nucleation. rOPN treated with protein kinase CK2 to phosphorylate the molecule (p-rOPN) produced an effect similar to that of nOPN, but at higher protein concentrations and to a lesser extent. These results suggest that phosphorylations are critical to OPN’s ability to inhibit nucleation, whereas the growth of the hydroxyapatite crystals is effectively controlled by the highly acidic OPN polypeptide. This work also demonstrates that dynamic light scattering can be a powerful tool for delineating the mechanism of protein modulation of mineral formation. PMID:23457612

  3. Fetal calf serum-mediated inhibition of neurite growth from ciliary ganglion neurons in vitro.

    PubMed

    Davis, G E; Skaper, S D; Manthorpe, M; Moonen, G; Varon, S

    1984-01-01

    Embryonic chick ciliary ganglion (CG) neurons cultured in fetal calf serum-containing medium have been previously reported to extend neurites on polyornithine (PORN) substrata precoated with a neurite-promoting factor (PNPF) from rat schwannoma-conditioned medium. On PORN substrata alone, however, no neuritic growth occurred. This was interpreted as evidence that PORN was an incompetent substratum for ciliary neuritic growth. In this study, we now find that an untreated PORN substratum allows neuritic growth in serum-free defined medium. When PNPF was added to PORN, a more rapid and extensive neuritic response occurred. After 5 hr of culture, a 60% neuritic response occurred on PNPF/PORN, whereas no neurons initiated neurites until 10-12 hr on PORN. The inhibitory effect of fetal calf serum noted above on PORN could be obtained in part by pretreating the substratum with serum for 1 hr. Maximal inhibitory effects in the PORN pretreatment were achieved after 30 min and were not further improved by treatments up to 4 hr. Bovine serum albumin was also found to inhibit neurite growth on PORN to about 60% of the inhibition obtained by an equivalent amount of serum protein. Fetal calf serum was shown to cause a 15% reduction in the percentage of neurons bearing neurites after its addition to 18-hr serum-free PORN cultures and to cause statistically significant reductions in neurite lengths measured 2 hr later.

  4. The flavonoid quercetin inhibits pancreatic cancer growth in vitro and in vivo

    PubMed Central

    Angst, Eliane; Park, Jenny L.; Moro, Aune; Lu, Qing-Yi; Lu, Xuyang; Li, Gang; King, Jonathan; Chen, Monica; Reber, Howard A.; Go, Vay Liang W.; Eibl, Guido; Hines, Oscar J.

    2012-01-01

    Objectives The flavonoid quercetin holds promise as an anti-tumor agent in several preclinical animal models. However, the efficacy of oral administration of quercetin in a pancreatic cancer mouse model is unknown. Methods The anti-proliferative effects of quercetin alone or in combination with gemcitabine were tested in two human pancreatic cancer cell lines using cell count and MTT assays. Apoptosis was evaluated by flow cytometry. Tumor growth in vivo was investigated in an orthotopic pancreatic cancer animal model using bioluminescence. Quercetin was administered orally in the diet. Results Quercetin inhibited the growth of pancreatic cancer cell lines, which was caused by an induction of apoptosis. In addition, dietary supplementation of quercetin attenuated the growth of orthotopically transplanted pancreatic xenografts. The combination of gemcitabine and quercetin had no additional effect compared to quercetin alone. In vivo quercetin caused significant apoptosis and reduced tumor cell proliferation. Conclusions Our data provide evidence that oral administration of quercetin was capable of inhibiting growth of orthotopic pancreatic tumors in a nude mouse model. These data suggest a possible benefit of quercetin in patients with pancreatic cancer. PMID:23000892

  5. Blockade of nonhormonal fibroblast growth factors by FP-1039 inhibits growth of multiple types of cancer.

    PubMed

    Harding, Thomas C; Long, Li; Palencia, Servando; Zhang, Hongbing; Sadra, Ali; Hestir, Kevin; Patil, Namrata; Levin, Anita; Hsu, Amy W; Charych, Deborah; Brennan, Thomas; Zanghi, James; Halenbeck, Robert; Marshall, Shannon A; Qin, Minmin; Doberstein, Stephen K; Hollenbaugh, Diane; Kavanaugh, W Michael; Williams, Lewis T; Baker, Kevin P

    2013-03-27

    The fibroblast growth factor (FGF) pathway promotes tumor growth and angiogenesis in many solid tumors. Although there has long been interest in FGF pathway inhibitors, development has been complicated: An effective FGF inhibitor must block the activity of multiple mitogenic FGF ligands but must spare the metabolic hormone FGFs (FGF-19, FGF-21, and FGF-23) to avoid unacceptable toxicity. To achieve these design requirements, we engineered a soluble FGF receptor 1 Fc fusion protein, FP-1039. FP-1039 binds tightly to all of the mitogenic FGF ligands, inhibits FGF-stimulated cell proliferation in vitro, blocks FGF- and vascular endothelial growth factor (VEGF)-induced angiogenesis in vivo, and inhibits in vivo growth of a broad range of tumor types. FP-1039 antitumor response is positively correlated with RNA levels of FGF2, FGF18, FGFR1c, FGFR3c, and ETV4; models with genetic aberrations in the FGF pathway, including FGFR1-amplified lung cancer and FGFR2-mutated endometrial cancer, are particularly sensitive to FP-1039-mediated tumor inhibition. FP-1039 does not appreciably bind the hormonal FGFs, because these ligands require a cell surface co-receptor, klotho or β-klotho, for high-affinity binding and signaling. Serum calcium and phosphate levels, which are regulated by FGF-23, are not altered by administration of FP-1039. By selectively blocking nonhormonal FGFs, FP-1039 treatment confers antitumor efficacy without the toxicities associated with other FGF pathway inhibitors.

  6. Autocrine growth inhibition by transforming growth factor β-1 (TGFβ-1) in human neuroendocrine tumour cells

    PubMed Central

    Wimmel, A; Wiedenmann, B; Rosewicz, S

    2003-01-01

    Background and aim: The role of transforming growth factor β-1 (TGFβ-1) in neuroendocrine tumour biology is currently unknown. We therefore examined the expression and biological significance of TGFβ signalling components in neuroendocrine tumours (NETs) of the gastroenteropancreatic (GEP) tract. Methods: Expression of TGFβ-1 and its receptors, Smads and Smad regulated proteins, was examined in surgically resected NET specimens and human NET cell lines by immunohistochemistry, reverse transcriptase-polymerase chain reaction, immunoblotting, and ELISA. Activation of TGFβ-1 dependent promoters was tested by transactivation assays. Growth regulation was evaluated by cell numbers, soft agar assays, and cell cycle analysis using flow cytometry. The role of endogenous TGFβ was assessed by a TGFβ neutralising antibody and stable transfection of a dominant negative TGFβR II receptor construct. Results: Coexpression of TGFβ-1 and its receptors TGFβR I and TGFβR II was detected in 67% of human NETs and in all three NET cell lines examined. NET cell lines expressed the TGFβ signal transducers Smad 2, 3, and 4. In two of the three cell lines, TGFβ-1 treatment resulted in transactivation of a TGFβ responsive reporter construct as well as inhibition of c-myc and induction of p21(WAF1) expression. TGFβ-1 inhibited anchorage dependent and independent growth in a time and dose dependent manner in TGFβ-1 responsive cell lines. TGFβ-1 mediated growth inhibition was due to G1 arrest without evidence of induction of apoptosis. Functional inactivation of endogenous TGFβ revealed the existence of an autocrine antiproliferative loop in NET cells. Conclusions: Neuroendocrine tumour cells of the gastroenteropancreatic tract are subject to paracrine and autocrine growth inhibition by TGFβ-1, which may account in part for the low proliferative index of this tumour entity. PMID:12912863

  7. Transforming growth factor-beta inhibition of proteasomal activity: a potential mechanism of growth arrest.

    PubMed

    Tadlock, Laura; Yamagiwa, Yoko; Hawker, James; Marienfeld, Carla; Patel, Tushar

    2003-08-01

    Although the proteasome plays a critical role in the controlled degradation of proteins involved in cell cycle control, the direct modulation of proteasomal function by growth regulatory signaling has not yet been demonstrated. We assessed the effect of transforming growth factor (TGF)-beta, a potent inhibitor of cell growth, on proteasomal function. TGF-beta selectively decreased hydrolysis of the proteasomal substrate Cbz-Leu-Leu-Leu-7-amido-4-methyl-coumarin (z-LLL-AMC) in a concentration-dependent manner but did not inhibit hydrolysis of other substrates Suc-Leu-Leu-Val-Tyr-AMC (suc-LLVY-AMC) or Cbz-Leu-Leu-Glu-AMC (z-LLE-AMC). An increase in intracellular oxidative injury occurred during incubation with TGF-beta. Furthermore, in vitro hydrolysis of z-LLL-AMC, but not suc-LLVY-AMC, was decreased by hydrogen peroxide. TGF-beta did not increase cellular expression of heat shock protein (HSP)90, a potent inhibitor of z-LLL-AMC hydrolysis in vitro. The physiological relevance of TGF-beta inhibition of proteasomal activity was studied by assessing the role of z-LLL-AMC hydrolysis on cyclin-dependent kinase inhibitor expression and cell growth. TGF-beta increased expression of p27KIP1 but did not alter expression of p21WAF1 or p16INK4A. The peptide aldehyde Cbz-Leu-Leu-leucinal (LLL-CHO or MG132) potently inhibited z-LLL-AMC hydrolysis in cell extracts as well as increasing p27KIP1 and decreasing cell proliferation. Thus growth inhibition by TGF-beta decreases a specific proteasomal activity via an HSP90-independent mechanism that may involve oxidative inactivation or modulation of proteasomal subunit composition and results in altered cellular expression of key cell cycle regulatory proteins such as p27KIP1.

  8. Receptor tyrosine kinase inhibition by regorafenib/sorafenib inhibits growth and invasion of meningioma cells.

    PubMed

    Tuchen, Marcus; Wilisch-Neumann, Annette; Daniel, Evelyn A; Baldauf, Lisa; Pachow, Doreen; Scholz, Johannes; Angenstein, Frank; Stork, Oliver; Kirches, Elmar; Mawrin, Christian

    2017-03-01

    Systemic chemotherapeutic treatment for unresectable and/or aggressive meningiomas is still unsatisfying. PDGF receptor (PDGFR)-mediated activation of mitogenic signalling has been shown to be active in meningiomas. Therefore, we evaluate in vitro and in vivo the effects of inhibiting PDGFR using the clinically well-characterised tyrosine kinase inhibitors sorafenib or regorafenib in meningioma models. IOMM-Lee meningioma cells were used to assess cytotoxic effects, inhibition of proliferation, induction of apoptosis, as well as inhibition of migration and motility by sorafenib and regorafenib. Using an orthotopic mouse xenograft model, growth inhibition as monitored by magnetic resonance imaging, and overall survival of sorafenib- or regorafenib-treated mice compared with control animals was determined. Treatment of malignant IOMM-Lee cells resulted in significantly reduced cell survival and induction of apoptosis following regorafenib and sorafenib treatment. Western blots showed that both drugs target phosphorylation of p44/42 ERK via downregulation of the PDGFR. Both drugs additionally showed significant inhibition of cell motility and invasion. In vivo, mice with orthotopic meningioma xenografts showed a reduced volume (n.s.) of signal enhancement in MRI (mainly tumour) following sorafenib and regorafenib treatment. This was translated in a significantly increased overall survival time (p ≤ 0.05) for regorafenib-treated mice. Analyses of in vivo-grown tumours demonstrated again reduced PDGFR expression and expression/phosphorylation of p44/42. Sorafenib and regorafenib show antitumour activity in vitro and in vivo by targeting PDGFR and p44/42 ERK signalling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. MicroRNA-375 inhibits colorectal cancer growth by targeting PIK3CA

    SciTech Connect

    Wang, Yihui; Tang, Qingchao; Li, Mingqi; Jiang, Shixiong; Wang, Xishan

    2014-02-07

    Highlights: • miR-375 is downregulated in colorectal cancer cell lines and tissues. • miR-375 inhibits colorectal cancer cell growth by targeting PIK3CA. • miR-375 inhibits colorectal cancer cell growth in xenograft nude mice model. - Abstract: Colorectal cancer (CRC) is the second most common cause of death from cancer. MicroRNAs (miRNAs) represent a class of small non-coding RNAs that control gene expression by triggering RNA degradation or interfering with translation. Aberrant miRNA expression is involved in human disease including cancer. Herein, we showed that miR-375 was frequently down-regulated in human colorectal cancer cell lines and tissues when compared to normal human colon tissues. PIK3CA was identified as a potential miR-375 target by bioinformatics. Overexpression of miR-375 in SW480 and HCT15 cells reduced PIK3CA protein expression. Subsequently, using reporter constructs, we showed that the PIK3CA untranslated region (3′-UTR) carries the directly binding site of miR-375. Additionally, miR-375 suppressed CRC cell proliferation and colony formation and led to cell cycle arrest. Furthermore, miR-375 overexpression resulted in inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. SiRNA-mediated silencing of PIK3CA blocked the inhibitory effect of miR-375 on CRC cell growth. Lastly, we found overexpressed miR-375 effectively repressed tumor growth in xenograft animal experiments. Taken together, we propose that overexpression of miR-375 may provide a selective growth inhibition for CRC cells by targeting PI3K/Akt signaling pathway.

  10. Inhibition of Glioblastoma Growth by the Thiadiazolidinone Compound TDZD-8

    PubMed Central

    Sanz-SanCristobal, Marina; Garcia-Cabezas, Miguel Angel; Santos, Angel; Perez-Castillo, Ana

    2010-01-01

    Background Thiadiazolidinones (TDZD) are small heterocyclic compounds first described as non-ATP competitive inhibitors of glycogen synthase kinase 3β (GSK-3β). In this study, we analyzed the effects of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), on murine GL261 cells growth in vitro and on the growth of established intracerebral murine gliomas in vivo. Methodology/Principal Findings Our data show that TDZD-8 decreased proliferation and induced apoptosis of GL261 glioblastoma cells in vitro, delayed tumor growth in vivo, and augmented animal survival. These effects were associated with an early activation of extracellular signal-regulated kinase (ERK) pathway and increased expression of EGR-1 and p21 genes. Also, we observed a sustained activation of the ERK pathway, a concomitant phosphorylation and activation of ribosomal S6 kinase (p90RSK) and an inactivation of GSK-3β by phosphorylation at Ser 9. Finally, treatment of glioblastoma stem cells with TDZD-8 resulted in an inhibition of proliferation and self-renewal of these cells. Conclusions/Significance Our results suggest that TDZD-8 uses a novel mechanism to target glioblastoma cells, and that malignant progenitor population could be a target of this compound. PMID:21079728

  11. Telomerase inhibition impairs tumor growth in glioblastoma xenografts.

    PubMed

    Falchetti, Maria Laura; Fiorenzo, Paolo; Mongiardi, Maria Patrizia; Petrucci, Giovanna; Montano, Nicola; Maira, Giulio; Pierconti, Francesco; Larocca, Luigi Maria; Levi, Andrea; Pallini, Roberto

    2006-07-01

    Telomerase is a specialized DNA polymerase that is required to replicate the ends of linear chromosomes, the telomeres. The majority of human cancers express high levels of telomerase activity that is permissive for tumor growth because it provides cells with an extended proliferative potential. Additionally, telomerase exerts cell growth promoting functions and favors cell survival. Human glioblastoma multiforme (GBM) cells express high level of telomerase activity owing to the overexpression of human telomerase reverse transcriptase (hTERT), the limiting subunit of the enzyme. Here we used retroviral mediated RNA interference to dampen down telomerase activity in two distinct human GBM cell lines, U87MG and TB10. Substantial decrease of hTERT mRNA and telomerase activity had only minimal effects on telomere length maintenance, cell growth and survival in vitro. On the contrary, development of tumors upon subcutaneously grafting of U87MG and TB10 cells and intracranial implantation of U87MG cells in nude athymic mice was strongly reduced by telomerase inhibition.

  12. Large plasma-membrane depolarization precedes rapid blue-light-induced growth inhibition in cucumber

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1989-01-01

    Blue-light (BL)-induced suppression of elongation of etiolated Cucumis sativus L. hypocotyls began after a 30-s lag time, which was halved by increasing the fluence rate from 10 to 100 micromoles m-2 s-1. Prior to the growth suppression, the plasma-membrane of the irradiated cells depolarized by as much as 100 mV, then returned within 2-3 min to near its initial value. The potential difference measured with surface electrodes changed with an identical time course but opposite polarity. The lag time for the change in surface potential showed an inverse dependence on fluence rate, similar to the lag for the growth inhibition. Green light and red light caused neither the electrical response nor the rapid inhibition of growth. The depolarization by BL did not propagate to nonirradiated regions and exhibited a refractory period of about 10 min following a BL pulse. Fluence-response relationships for the electrical and growth responses provide correlational evidence that the plasma-membrane depolarization reflects an event in the transduction chain of this light-growth response.

  13. Large plasma-membrane depolarization precedes rapid blue-light-induced growth inhibition in cucumber

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1989-01-01

    Blue-light (BL)-induced suppression of elongation of etiolated Cucumis sativus L. hypocotyls began after a 30-s lag time, which was halved by increasing the fluence rate from 10 to 100 micromoles m-2 s-1. Prior to the growth suppression, the plasma-membrane of the irradiated cells depolarized by as much as 100 mV, then returned within 2-3 min to near its initial value. The potential difference measured with surface electrodes changed with an identical time course but opposite polarity. The lag time for the change in surface potential showed an inverse dependence on fluence rate, similar to the lag for the growth inhibition. Green light and red light caused neither the electrical response nor the rapid inhibition of growth. The depolarization by BL did not propagate to nonirradiated regions and exhibited a refractory period of about 10 min following a BL pulse. Fluence-response relationships for the electrical and growth responses provide correlational evidence that the plasma-membrane depolarization reflects an event in the transduction chain of this light-growth response.

  14. Blocking Fibroblast Growth Factor Receptor Signaling Inhibits Tumor Growth, Lymphangiogenesis, and Metastasis

    PubMed Central

    Larrieu-Lahargue, Frédéric; Welm, Alana L.; Bouchecareilh, Marion; Alitalo, Kari; Li, Dean Y.; Bikfalvi, Andreas; Auguste, Patrick

    2012-01-01

    Fibroblast Growth Factor receptor (FGFR) activity plays crucial roles in tumor growth and patient survival. However, FGF (Fibroblast Growth Factor) signaling as a target for cancer therapy has been under-investigated compared to other receptor tyrosine kinases. Here, we studied the effect of FGFR signaling inhibition on tumor growth, metastasis and lymphangiogenesis by expressing a dominant negative FGFR (FGFR-2DN) in an orthotopic mouse mammary 66c14 carcinoma model. We show that FGFR-2DN-expressing 66c14 cells proliferate in vitro slower than controls. 66c14 tumor outgrowth and lung metastatic foci are reduced in mice implanted with FGFR-2DN-expressing cells, which also exhibited better overall survival. We found 66c14 cells in the lumen of tumor lymphatic vessels and in lymph nodes. FGFR-2DN-expressing tumors exhibited a decrease in VEGFR-3 (Vascular Endothelial Growth Factor Receptor-3) or podoplanin-positive lymphatic vessels, an increase in isolated intratumoral lymphatic endothelial cells and a reduction in VEGF-C (Vascular Endothelial Growth Factor-C) mRNA expression. FGFs may act in an autocrine manner as the inhibition of FGFR signaling in tumor cells suppresses VEGF-C expression in a COX-2 (cyclooxygenase-2) or HIF1-α (hypoxia-inducible factor-1 α) independent manner. FGFs may also act in a paracrine manner on tumor lymphatics by inducing expression of pro-lymphangiogenic molecules such as VEGFR-3, integrin α9, prox1 and netrin-1. Finally, in vitro lymphangiogenesis is impeded in the presence of FGFR-2DN 66c14 cells. These data confirm that both FGF and VEGF signaling are necessary for the maintenance of vascular morphogenesis and provide evidence that targeting FGFR signaling may be an interesting approach to inhibit tumor lymphangiogenesis and metastatic spread. PMID:22761819

  15. Gene Transposition Causing Natural Variation for Growth in Arabidopsis thaliana

    PubMed Central

    Vlad, Daniela; Rappaport, Fabrice; Simon, Matthieu; Loudet, Olivier

    2010-01-01

    A major challenge in biology is to identify molecular polymorphisms responsible for variation in complex traits of evolutionary and agricultural interest. Using the advantages of Arabidopsis thaliana as a model species, we sought to identify new genes and genetic mechanisms underlying natural variation for shoot growth using quantitative genetic strategies. More quantitative trait loci (QTL) still need be resolved to draw a general picture as to how and where in the pathways adaptation is shaping natural variation and the type of molecular variation involved. Phenotypic variation for shoot growth in the Bur-0 × Col-0 recombinant inbred line set was decomposed into several QTLs. Nearly-isogenic lines generated from the residual heterozygosity segregating among lines revealed an even more complex picture, with major variation controlled by opposite linked loci and masked by the segregation bias due to the defective phenotype of SG3 (Shoot Growth-3), as well as epistasis with SG3i (SG3-interactor). Using principally a fine-mapping strategy, we have identified the underlying gene causing phenotypic variation at SG3: At4g30720 codes for a new chloroplast-located protein essential to ensure a correct electron flow through the photosynthetic chain and, hence, photosynthesis efficiency and normal growth. The SG3/SG3i interaction is the result of a structural polymorphism originating from the duplication of the gene followed by divergent paralogue's loss between parental accessions. Species-wide, our results illustrate the very dynamic rate of duplication/transposition, even over short periods of time, resulting in several divergent—but still functional—combinations of alleles fixed in different backgrounds. In predominantly selfing species like Arabidopsis, this variation remains hidden in wild populations but is potentially revealed when divergent individuals outcross. This work highlights the need for improved tools and algorithms to resolve structural variation

  16. Gigantism caused by growth hormone secreting pituitary adenoma.

    PubMed

    Rhee, Noorisaem; Jeong, Kumi; Yang, Eun Mi; Kim, Chan Jong

    2014-06-01

    Gigantism indicates excessive secretion of growth hormones (GH) during childhood when open epiphyseal growth plates allow for excessive linear growth. Case one involved a 14.7-year-old boy presented with extreme tall stature. His random serum GH level was 38.4 ng/mL, and failure of GH suppression was noted during an oral glucose tolerance test (OGTT; nadir serum GH, 22.7 ng/mL). Magnetic resonance imaging (MRI) of the brain revealed a 12-mm-sized pituitary adenoma. Transsphenoidal surgery was performed and a pituitary adenoma displaying positive immunohistochemical staining for GH was reported. Pituitary MRI scan was performed 4 months after surgery and showed recurrence/residual tumor. Medical treatment with a long-acting somatostatin analogue for six months was unsuccessful. As a result, secondary surgery was performed. Three months after reoperation, the GH level was 0.2 ng/mL and insulin-like growth factor 1 was 205 ng/mL. Case two involved a 14.9-year-old boy, who was referred to our department for his tall stature. His basal GH level was 9.3 ng/mL, and failure of GH suppression was reported during OGTT (nadir GH, 9.0 ng/mL). Pituitary MRI showed a 6-mm-sized pituitary adenoma. Surgery was done and histopathological examination demonstrated a pituitary adenoma with positive staining for GH. Three months after surgery, the GH level was 0.2 ng/mL and nadir GH during OGTT was less than 0.1 ng/mL. Pituitary MRI scans showed no residual tumor. We present two cases of gigantism caused by a GH-secreting pituitary adenoma with clinical and microscopic findings.

  17. Gigantism caused by growth hormone secreting pituitary adenoma

    PubMed Central

    Rhee, Noorisaem; Jeong, Kumi; Yang, Eun Mi

    2014-01-01

    Gigantism indicates excessive secretion of growth hormones (GH) during childhood when open epiphyseal growth plates allow for excessive linear growth. Case one involved a 14.7-year-old boy presented with extreme tall stature. His random serum GH level was 38.4 ng/mL, and failure of GH suppression was noted during an oral glucose tolerance test (OGTT; nadir serum GH, 22.7 ng/mL). Magnetic resonance imaging (MRI) of the brain revealed a 12-mm-sized pituitary adenoma. Transsphenoidal surgery was performed and a pituitary adenoma displaying positive immunohistochemical staining for GH was reported. Pituitary MRI scan was performed 4 months after surgery and showed recurrence/residual tumor. Medical treatment with a long-acting somatostatin analogue for six months was unsuccessful. As a result, secondary surgery was performed. Three months after reoperation, the GH level was 0.2 ng/mL and insulin-like growth factor 1 was 205 ng/mL. Case two involved a 14.9-year-old boy, who was referred to our department for his tall stature. His basal GH level was 9.3 ng/mL, and failure of GH suppression was reported during OGTT (nadir GH, 9.0 ng/mL). Pituitary MRI showed a 6-mm-sized pituitary adenoma. Surgery was done and histopathological examination demonstrated a pituitary adenoma with positive staining for GH. Three months after surgery, the GH level was 0.2 ng/mL and nadir GH during OGTT was less than 0.1 ng/mL. Pituitary MRI scans showed no residual tumor. We present two cases of gigantism caused by a GH-secreting pituitary adenoma with clinical and microscopic findings. PMID:25077093

  18. Ethylenediamine Promotes Cu Nanowire Growth by Inhibiting Oxidation of Cu(111).

    PubMed

    Kim, Myung Jun; Flowers, Patrick F; Stewart, Ian E; Ye, Shengrong; Baek, Seungyeon; Kim, Jae Jeong; Wiley, Benjamin J

    2017-01-11

    The synthesis of metal nanostructures usually requires a capping agent that is generally thought to cause anisotropic growth by blocking the addition of atoms to specific crystal facets. This work uses a series of electrochemical measurements with a quartz crystal microbalance and single-crystal electrodes to elucidate the facet-selective chemistry occurring in the synthesis of Cu nanowires. Contrary to prevailing hypotheses, ethylenediamine, a so-called capping agent in the synthesis of Cu nanowires, causes anisotropic growth by increasing the rate of atomic addition to (111) facets at the end of a growing nanowire relative to (100) facets on the sides of a nanowire. Ethylenediamine increases the reduction rate of Cu(OH)2(-) on a Cu(111) surface relative to Cu(100) by selectively inhibiting the formation of Cu oxide on Cu(111). This work demonstrates how studying facet-selective electrochemistry can improve the understanding of the processes by which atoms assemble to form anisotropic metal nanostructures.

  19. The human asparaginase enzyme (ASPG) inhibits growth in leukemic cells

    PubMed Central

    Belviso, Stefania; Amato, Rosario; Perrotti, Nicola; Menniti, Miranda

    2017-01-01

    The human protein ASPG is an enzyme with a putative antitumor activity. We generated in bacteria and then purified a recombinant GST-ASPG protein that we used to characterize the biochemical and cytotoxic properties of the human ASPG. We demonstrated that ASPG possesses asparaginase and PAF acetylhydrolase activities that depend on a critical threonine residue at position 19. Consistently, ASPG but not its T19A mutant showed cytotoxic activity in K562, NALM-6 and MOLT-4 leukemic cell lines but not in normal cells. Regarding the mechanism of action of ASPG, it was able to induce a significant apoptotic death in K562 cells. Taken together our data suggest that ASPG, combining different enzymatic activities, should be considered a promising anti-cancer agent for inhibiting the growth of leukemia cells. PMID:28542249

  20. Inhibiting action of carbohydrates on the growth of fluorapatite crystals.

    PubMed

    Matsumoto, T; Okazaki, M; Taira, M; Takahashi, J

    2000-01-01

    Hydroxyapatite (HAp) and fluorapatite (FAp) were synthesized in the presence of carbohydrates (glucose, fructose, galactose and sucrose). X-ray diffraction analysis showed that the crystallinity of two FAp groups that were synthesized in the presence of glucose or sucrose decreased with the increase in carbohydrate content. In SEM photographs we found that the size of their crystals was small and the shape changed. However, FAp groups that were snythesized in the presence of fructose or galactose showed little change in their crystallinity and shape. Four carbohydrates had some influence on size, but not on shape or crystallinity when synthesizing HAp. These results suggest that glucose and/or sucrose has a chemical affinity to FAp and inhibits the growth of FAp crystals.

  1. Antibacterial activity of lichen secondary metabolite usnic acid is primarily caused by inhibition of RNA and DNA synthesis.

    PubMed

    Maciąg-Dorszyńska, Monika; Węgrzyn, Grzegorz; Guzow-Krzemińska, Beata

    2014-04-01

    Usnic acid, a compound produced by various lichen species, has been demonstrated previously to inhibit growth of different bacteria and fungi; however, mechanism of its antimicrobial activity remained unknown. In this report, we demonstrate that usnic acid causes rapid and strong inhibition of RNA and DNA synthesis in Gram-positive bacteria, represented by Bacillus subtilis and Staphylococcus aureus, while it does not inhibit production of macromolecules (DNA, RNA, and proteins) in Escherichia coli, which is resistant to even high doses of this compound. However, we also observed slight inhibition of RNA synthesis in a Gram-negative bacterium, Vibrio harveyi. Inhibition of protein synthesis in B. subtilis and S. aureus was delayed, which suggest indirect action (possibly through impairment of transcription) of usnic acid on translation. Interestingly, DNA synthesis was halted rapidly in B. subtilis and S. aureus, suggesting interference of usnic acid with elongation of DNA replication. We propose that inhibition of RNA synthesis may be a general mechanism of antibacterial action of usnic acid, with additional direct mechanisms, such as impairment of DNA replication in B. subtilis and S. aureus.

  2. P2×7 targeting inhibits growth of human mesothelioma

    PubMed Central

    Amoroso, Francesca; Salaro, Erica; Falzoni, Simonetta; Chiozzi, Paola; Giuliani, Anna Lisa; Cavallesco, Giorgio; Maniscalco, Pio; Puozzo, Andrea; Bononi, Ilaria; Martini, Fernanda; Tognon, Mauro; Virgilio, Francesco Di

    2016-01-01

    Malignant pleural mesothelioma (MPM) is an aggressive tumor refractory to anti-blastic therapy. MPM cells show several genetic and biochemical defects, e.g. overexpression of oncogenes, downregulation of onco-suppressor genes, dysregulation of microRNA, or alteration of intracellular Ca2+ homeostasis and of apoptosis. No information is as yet available on purinergic signalling in this tumor. Signalling via the P2×7 (P2RX7 or P2×7R) purinergic receptor is attracting increasing attention as a pathway involved in cancer cell death or proliferation. In this report we show that the P2×7R is expressed by three MPM cell lines established from MPM patients but not by mesothelial cells from healthy subjects (healthy mesothelial cells, HMCs). MPM cell proliferation was inhibited by in vitro incubation in the presence of selective P2×7R antagonists, as well as by stimulation with the P2×7R agonist BzATP. Systemic administration of the selective P2×7R blocker AZ10606120 inhibited in vivo growth of MPM tumors whether implanted subcutaneously (s.c.) or intraperitoneally (i.p.). Our findings suggest that the P2×7R might be a novel target for the therapy of mesothelioma. PMID:27391069

  3. Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems.

    PubMed

    Mercy, Chryslène; Ize, Bérengère; Salcedo, Suzana P; de Bentzmann, Sophie; Bigot, Sarah

    2016-01-01

    Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI- bacteria. CDI+ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the "E. coli"- and "Burkholderia-type". CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae.

  4. Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems

    PubMed Central

    Mercy, Chryslène; Ize, Bérengère; Salcedo, Suzana P.; de Bentzmann, Sophie; Bigot, Sarah

    2016-01-01

    Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI- bacteria. CDI+ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the “E. coli”- and “Burkholderia-type”. CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae. PMID:26808644

  5. Exposure to Asulox Inhibits the Growth of Mosses

    PubMed Central

    ROWNTREE, J. K.; LAWTON, K. F.; RUMSEY, F. J.; SHEFFIELD, E.

    2003-01-01

    Asulox is a herbicide used to control bracken. Its effects on mosses were investigated to ascertain whether exposure proved as detrimental as found in parallel studies on pteridophytes. Mature gametophytes of 18 mosses were exposed to a range of concentrations of Asulox under standard conditions and the effects on growth monitored. Plants were cut to a standard length, exposed to Asulox solution for 24 h, grown for 3 weeks and total elongation (main stem and branches) measured. EC50 values were calculated and species ranked according to sensitivity. The effects of exposure on total elongation were compared with those on main stem elongation alone. Under the conditions tested, the total elongation of all species was inhibited after exposure to Asulox. The amount of elongation observed after exposure was different for different species and inhibition of elongation occurred at different exposure concentrations. A single regression equation was not adequate to describe the dose response curves of all species tested. An ability to produce secondary branches may confer increased tolerance to Asulox exposure. It is concluded that mosses suffer detrimental effects after exposure to Asulox at concentrations similar to those that affect fern gametophytes such as bracken. PMID:12933364

  6. Inhibition of microbial growth on chitosan membranes by plasma treatment.

    PubMed

    de Oliveira Cardoso Macêdo, Marina; de Macêdo, Haroldo Reis Alves; Gomes, Dayanne Lopes; de Freitas Daudt, Natália; Rocha, Hugo Alexandre Oliveira; Alves, Clodomiro

    2013-11-01

    The use of polymeric medical devices has stimulated the development of new sterilization methods. The traditional techniques rely on ethylene oxide, but there are many questions concerning the carcinogenic properties of the ethylene oxide residues adsorbed on the materials after processing. Another common technique is the gamma irradiation process, but it is costly, its safe operation requires an isolated site, and it also affects the bulk properties of the polymers. The use of gas plasma is an elegant alternative sterilization technique. The plasma promotes efficient inactivation of the microorganisms, minimizes damage to the materials, and presents very little danger for personnel and the environment. In this study we used plasma for microbial inhibition of chitosan membranes. The membranes were treated with oxygen, methane, or argon plasma for different time periods (15, 30, 45, or 60 min). For inhibition of microbial growth with oxygen plasma, the time needed was 60 min. For the methane plasma, samples were successfully treated after 30, 45, and 60 min. For argon plasma, all treatment periods were effective. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  7. Argos inhibits epidermal growth factor receptor signalling by ligand sequestration.

    PubMed

    Klein, Daryl E; Nappi, Valerie M; Reeves, Gregory T; Shvartsman, Stanislav Y; Lemmon, Mark A

    2004-08-26

    The epidermal growth factor receptor (EGFR) has critical functions in development and in many human cancers. During development, the spatial extent of EGFR signalling is regulated by feedback loops comprising both well-understood activators and less well-characterized inhibitors. In Drosophila melanogaster the secreted protein Argos functions as the only known extracellular inhibitor of EGFR, with clearly identified roles in multiple stages of development. Argos is only expressed when the Drosophila EGFR (DER) is activated at high levels, and downregulates further DER signalling. Although there is ample genetic evidence that Argos inhibits DER activation, the biochemical mechanism has not been established. Here we show that Argos inhibits DER signalling without interacting directly with the receptor, but instead by sequestering the DER-activating ligand Spitz. Argos binds tightly to the EGF motif of Spitz and forms a 1:1 (Spitz:Argos) complex that does not bind DER in vitro or at the cell surface. Our results provide an insight into the mechanism of Argos function, and suggest new strategies for EGFR inhibitor design.

  8. Isoproterenol inhibits fibroblast growth factor-2-induced growth of renal epithelial cells.

    PubMed

    Izevbigie, E B; Gutkind, J S; Ray, P E

    2000-08-01

    The signal transduction pathways modulating bFGF effects in renal tubular epithelial cells (RTEc) are not completely understood. Since the cAMP and the mitogen-activated protein kinase (MAPK) pathways can modulate the growth of RTEc, we studied whether two cAMP elevating agents, isoproterenol and 8-bromo-cAMP, would modulate basic fibroblast growth factor (bFGF) induction of MAPK activity (ERK-2) and cell proliferation in human renal proximal tubular epithelial cells (RPTEc) and Madin-Darby canine kidney cells (MDCK clone EI1). Isoproterenol, but not bFGF, stimulated cAMP production in RPTEc and MDCKEI1 cells. bFGF, isoproterenol, and 8-bromo-cAMP alone increased ERK-2 activity in both cell types. However, isoproterenol and 8-bromo-cAMP partially inhibited the bFGF induction of ERK-2 activity, but only isoproterenol inhibited the proliferation of both cell types. PD098059 (25 microM), an inhibitor of MAPK kinase (MEK 1/2), blocked the bFGF mitogenic effects, but did not affect the 8-bromo-cAMP-induced mitogenic effects in MDCKEI1 cells. These findings suggest that activation of ERK-2 is required but not sufficient for mitogenesis in RTEc. We conclude that isoproterenol inhibits the growth-promoting effects of bFGF in RTEc via MEK-dependent and -independent pathways.

  9. Magnetic fluid hyperthermia inhibits the growth of breast carcinoma and downregulates vascular endothelial growth factor expression.

    PubMed

    Wang, Guihua; Xu, Derong; Chai, Qin; Tan, Xiaolang; Zhang, Yu; Gu, Ning; Tang, Jintian

    2014-05-01

    The application of magnetic fluid hyperthermia (MFH) with nanoparticles has been shown to inhibit tumor growth in several animal models. However, the feasibility of using MFH in vivo to treat breast cancer is uncertain, and the mechanism is unclear. In the present study, it was observed that the intratumoral administration of MFH induced hyperthermia significantly in rats with Walker-265 breast carcinomas. The hyperthermia treatment with magnetic nanoparticles inhibited tumor growth in vivo and promoted the survival of the tumor-bearing rats. Furthermore, it was found that MFH treatment downregulated the protein expression of vascular endothelial growth factor (VEGF) in the tumor tissue, as observed by immunohistochemistry. MFH treatment also decreased the gene expression of VEGF and its receptors, VEGF receptor 1 and 2, and inhibited angiogenesis in the tumor tissues. Taken together, these results indicate that the application of MFH with nanoparticles is feasible for the treatment of breast carcinoma. The MFH-induced downregulation of angiogenesis may also contribute to the induction of an anti-tumor effect.

  10. Growth Impairment Caused by Raw Linseed Consumption: Can Trypsin Inhibitors Be Harmful for Health?

    PubMed

    Anaya, Katya; Cruz, Ana C B; Cunha, Dayse C S; Monteiro, Sandra M N; Dos Santos, Elizeu A

    2015-09-01

    Linseed (Linun usitatissimum L.) is an important oilseed whose nutritional value can be impaired due to presence of antinutritional factors and low protein digestibility. Protein fractions from raw linseed meal were extracted, isolated and analyzed in vitro and in vivo. Globulins, the major protein fraction of linseed, showed low in vitro susceptibility to trypsin and chymotrypsin, but its in vivo digestibility was 93.2 %. Albumin fraction had high trypsin inhibition activity (5250 Inhibition Units g(-1)) and presented low molecular mass protein bands, similar to known trypsin inhibitors. Raw linseed consumption caused negative effects on rat growth and reduction of intestinal villi. Results indicate that raw linseed meal must not be used as an exclusive source of protein regardless of the major proteins have high digestibility; digestive enzymes inhibitors in raw linseed probably reduces the protein utilization.

  11. Kaempferol inhibits Entamoeba histolytica growth by altering cytoskeletal functions.

    PubMed

    Bolaños, Verónica; Díaz-Martínez, Alfredo; Soto, Jacqueline; Marchat, Laurence A; Sanchez-Monroy, Virginia; Ramírez-Moreno, Esther

    2015-11-01

    The flavonoid kaempferol obtained from Helianthemum glomeratum, an endemic Mexican medicinal herb used to treat gastrointestinal disorders, has been shown to inhibit growth of Entamoeba histolytica trophozoites in vitro; however, the mechanisms associated with this activity have not been documented. Several works reported that kaempferol affects cytoskeleton in mammalian cells. In order to gain insights into the action mechanisms involved in the anti-amoebic effect of kaempferol, here we evaluated the effect of this compound on the pathogenic events driven by the cytoskeleton during E. histolytica infection. We also carried out a two dimensional gel-based proteomic analysis to evidence modulated proteins that could explain the phenotypical changes observed in trophozoites. Our results showed that kaempferol produces a dose-dependent effect on trophozoites growth and viability with optimal concentration being 27.7 μM. Kaempferol also decreased adhesion, it increased migration and phagocytic activity, but it did not affect erythrocyte binding nor cytolytic capacity of E. histolytica. Congruently, proteomic analysis revealed that the cytoskeleton proteins actin, myosin II heavy chain and cortexillin II were up-regulated in response to kaempferol treatment. In conclusion, kaempferol anti-amoebic effects were associated with deregulation of proteins related with cytoskeleton, which altered invasion mechanisms.

  12. Aristolochic Acid I Causes Testis Toxicity by Inhibiting Akt and ERK1/2 Phosphorylation.

    PubMed

    Kwak, Dong Hoon; Lee, Seoul

    2016-01-19

    Aristolochic acid (AA) is a natural bioactive substance found in Chinese herbs that induce toxicity during ovarian maturation of animals and humans. Apoptosis is induced by various types of damage and governs the progression of biological cell removal that controls the equilibrium between cell growth and death. However, the AA toxicity mechanism during testis maturation in mouse has not been elucidated and was thus the focus of the present study. This study used TM4 Sertoli cells and an ICR mouse model, both of which were injected with aristolochic acid I (AAI) for 4 weeks. Testis dimensions and weight were surveyed to define AAI cytotoxicity in the mice testis. The MTT assay was used to analyze the cytotoxicity of AAI in TM4 Sertoli cells. An apoptosis expression mediator was analyzed through Western blotting, while the measure of apoptosis-induced cell death of TM4 Sertoli cells and testis tissues was analyzed by the TUNEL assay. We found that AAI strongly inhibits survival in TM4 cells and that AAI significantly activated apoptosis-induced cell death in TM4 Sertoli cells and mice testis tissue. In addition, AAI suppressed the expression of B-cell lymphoma 2 (Bcl-2), a factor related to anti-apoptosis. It markedly improved pro-apoptotic protein expression, including Bcl-2-associated X protein, poly(ADP-ribose) polymerase, and caspase-3 and -9. Furthermore, we observed that AAI significantly reduced the size and weight of mouse testis. Moreover, germ cells and somatic cells in testis were markedly damaged by AAI. In addition, we found that AAI significantly inhibits ERK1/2 and Akt activation in TM4 Sertoli cells and testis tissue. The data obtained in this study indicate that AAI causes severe injury for the period of testis development by impeding apoptosis related to the Akt and ERK1/2 pathway.

  13. Selective inhibition of tumoral cells growth by low power millimeter waves.

    PubMed

    Chidichimo, Giuseppe; Beneduci, Amerigo; Nicoletta, Maria; Critelli, Maria; De Rose, Renata; Tkatchenko, Yury; Abonante, Sergio; Tripepi, Sandro; Perrotta, Enrico

    2002-01-01

    The effects of low power millimetric wave (MMW) radiation on the growth of tumor and healthy cells were studied. A wide-band frequency range between 53.57-78.33 GHz with a radiation density power of 27 x 10(-17) watt/Hz were used. The radiating energy was low enough not to increase the temperature of the cellular samples (cold irradiation). One hour of radiation treatment given every other day to three tumoral human stable cell lines, produced a noticeable inhibition of the cellular growth. The analogous treatment given to two healthy cell lines gave a weak growth stimulation. A scanning electron microscopy study of MCF-7-and K562-irradiated cells revealed that MMW irradiation induced profound morphological changes of the membrane. Finally, we also provided a mechanistic indication, based on millimeter wave spectroscopy of the cells: water is the primary absorber of these electromagnetic waves. Our work provides interesting evidence that wide band low power MMW irradiation, in the appropriate frequency range, could be used in the future as a cold means to cause selective inhibition of tumor cell growth.

  14. Amygdalin inhibits the growth of renal cell carcinoma cells in vitro.

    PubMed

    Juengel, Eva; Thomas, Anita; Rutz, Jochen; Makarevic, Jasmina; Tsaur, Igor; Nelson, Karen; Haferkamp, Axel; Blaheta, Roman A

    2016-02-01

    Although amygdalin is used by many cancer patients as an antitumor agent, there is a lack of information on the efficacy and toxicity of this natural compound. In the present study, the inhibitory effect of amygdalin on the growth of renal cell carcinoma (RCC) cells was examined. Amygdalin (10 mg/ml) was applied to the RCC cell lines, Caki-1, KTC-26 and A498, for 24 h or 2 weeks. Untreated cells served as controls. Tumor cell growth and proliferation were determined using MTT and BrdU tests, and cell cycle phases were evaluated. Expression of the cell cycle activating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1 and D3 as well as of the cell cycle inhibiting proteins p19 and p27 was examined by western blot analysis. Surface expression of the differentiation markers E- and N-cadherin was also investigated. Functional blockade by siRNA was used to determine the impact of several proteins on tumor cell growth. Amygdalin treatment caused a significant reduction in RCC cell growth and proliferation. This effect was correlated with a reduced percentage of G2/M-phase RCC cells and an increased percentage of cells in the G0/1-phase (Caki-1 and A498) or cell cycle arrest in the S-phase (KTC-26). Furthermore, amygdalin induced a marked decrease in cell cycle activating proteins, in particular cdk1 and cyclin B. Functional blocking of cdk1 and cyclin B resulted in significantly diminished tumor cell growth in all three RCC cell lines. Aside from its inhibitory effects on growth, amygdalin also modulated the differentiation markers, E- and N-cadherin. Hence, exposing RCC cells to amygdalin inhibited cell cycle progression and tumor cell growth by impairing cdk1 and cyclin B expression. Moreover, we noted that amygdalin affected differentiation markers. Thus, we suggest that amygdalin exerted RCC antitumor effects in vitro.

  15. Involvement of insulin-like growth factor binding protein-3 in peroxisome proliferator-activated receptor gamma-mediated inhibition of breast cancer cell growth.

    PubMed

    Pon, Cindy K; Firth, Sue M; Baxter, Robert C

    2015-01-05

    We have previously reported that insulin-like growth factor binding protein-3 (IGFBP-3), a protein with dichotomous effects on both cell proliferation and cell survival, interacts with peroxisome proliferator-activated receptor gamma (PPARγ) and inhibits adipogenic PPARγ signaling. We now show that IGFBP-3 and PPARγ interact in breast cancer cells, through amino- and carboxyl-terminal residues of IGFBP-3. IGFBP-3 and the PPARγ ligands, rosiglitazone or 15-deoxy-Δ(12,14)-prostaglandin J2, separately inhibited the proliferation of MCF-7, MDA-MB-231 and MDA-MB-468 breast cancer cells. However, growth inhibition by IGFBP-3 and PPARγ ligand combined was greater than by either alone. Two IGFBP-3 mutants with reduced PPARγ binding caused no growth inhibition when used alone and abolished the inhibitory effect of rosiglitazone when used in combination with PPARγ ligand. Cell growth inhibition by PPARγ ligands was substantially blocked by IGFBP-3 siRNA and restored by exogenous IGFBP-3. We conclude that the interaction between IGFBP-3 and PPARγ is important for the growth-inhibitory effect of PPARγ ligands in human breast cancer cells, suggesting that IGFBP-3 expression by breast tumors may regulate their sensitivity toward PPARγ ligands. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Quantitative Analysis of the Modes of Growth Inhibition by Weak Organic Acids in Saccharomyces cerevisiae

    PubMed Central

    Ullah, Azmat; Orij, Rick; Brul, Stanley

    2012-01-01

    Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pHi, was a determinant for growth inhibition. This pHi recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHi upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport. PMID:23001666

  17. Quantitative analysis of the modes of growth inhibition by weak organic acids in Saccharomyces cerevisiae.

    PubMed

    Ullah, Azmat; Orij, Rick; Brul, Stanley; Smits, Gertien J

    2012-12-01

    Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pH(i)) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pH(i), was a determinant for growth inhibition. This pH(i) recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pH(i), and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pH(i) upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport.

  18. Growth inhibition of Streptococcus mutans by cellular extracts of human intestinal lactic acid bacteria.

    PubMed Central

    Ishihara, K; Miyakawa, H; Hasegawa, A; Takazoe, I; Kawai, Y

    1985-01-01

    The in vitro growth of Streptococcus mutans was completely inhibited by water-soluble extracts from cells of various intestinal lactic acid bacteria identified as Streptococcus faecium, Streptococcus equinus, Lactobacillus fermentum, and Lactobacillus salivarius. The growth inhibition was dependent on the concentrations of the extracts. In contrast, the extracts did not inhibit the growth of the major indigenous intestinal lactic acid bacteria isolated from humans. These lactic acid bacteria were not acutely toxic in mice. PMID:4030098

  19. Heparin Inhibits Hepatocyte Growth Factor Induced Motility and Invasion of Hepatocellular Carcinoma Cells through Early Growth Response Protein 1

    PubMed Central

    Ozen, Evin; Gozukizil, Aysim; Erdal, Esra; Uren, Aykut; Bottaro, Donald P.; Atabey, Nese

    2012-01-01

    The Hepatocyte Growth Factor (HGF)/c-Met signaling pathway regulates hepatocyte proliferation, and pathway aberrations are implicated in the invasive and metastatic behaviors of hepatocellular carcinoma (HCC). In addition to c-Met, heparin acts as a co-receptor to modulate pathway activity. Recently, anti-metastatic and anti-cancer effects of heparin have been reported. However, the role of heparin in the regulation of HGF signaling remains controversial and the effects of heparin on HGF-induced biological responses during hepatocarcinogenesis is not yet defined. In this study we determined the effects of heparin on HGF-induced activities of HCC cells and the underlying molecular mechanisms. Here, we report for the first time that heparin inhibits HGF-induced adhesion, motility and invasion of HCC cells. In addition, heparin reduced HGF-induced activation of c-Met and MAPK in a dose-dependent manner, as well as decreased transcriptional activation and expression of Early growth response factor 1 (Egr1). HGF-induced MMP-2 and MMP-9 activation, and MT1-MMP expression, also were inhibited by heparin. Stable knockdown of Egr1 caused a significant decrease in HGF-induced invasion, as well as the activation and expression of MMPs. Parallel to these findings, the overexpression of Egr1 increased the invasiveness of HCC cells. Our results suggest that Egr1 activates HGF-induced cell invasion through the regulation of MMPs in HCC cells and heparin inhibits HGF-induced cellular invasion via the downregulation of Egr1. Therefore, heparin treatment might be a therapeutic approach to inhibit invasion and metastasis of HCC, especially for patients with active HGF/c-Met signaling. PMID:22912725

  20. Host-induced gene silencing inhibits the biotrophic pathogen causing downy mildew of lettuce.

    PubMed

    Govindarajulu, Manjula; Epstein, Lynn; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-09-01

    Host-induced gene silencing (HIGS) is an RNA interference-based approach in which small interfering RNAs (siRNAs) are produced in the host plant and subsequently move into the pathogen to silence pathogen genes. As a proof-of-concept, we generated stable transgenic lettuce plants expressing siRNAs targeting potentially vital genes of Bremia lactucae, a biotrophic oomycete that causes downy mildew, the most important disease of lettuce worldwide. Transgenic plants, expressing inverted repeats of fragments of either the Highly Abundant Message #34 (HAM34) or Cellulose Synthase (CES1) genes of B. lactucae, specifically suppressed expression of these genes, resulting in greatly reduced growth and inhibition of sporulation of B. lactucae. This demonstrates that HIGS can provide effective control of B. lactucae in lettuce; such control does not rely on ephemeral resistance conferred by major resistance genes and therefore offers new opportunities for durable control of diverse diseases in numerous crops. © 2014 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Stunted Growth Caused by Blast Disease in Rice Seedlings Is Associated with Changes in Phytohormone Signaling Pathways.

    PubMed

    Jiang, Chang-Jie; Liu, Xiao-Long; Liu, Xin-Qiong; Zhang, Hui; Yu, Ying-Jie; Liang, Zheng-Wei

    2017-01-01

    In response to pathogen attack, plants prioritize defense reactions generally at the expense of plant growth. In this work, we report that changes in phytohormone signaling pathways are associated with the stunted plant growth caused by blast disease in rice seedlings. Infection of rice seedlings with blast fungus Magnaporthe oryzae (race 007.0) at the four-leaf stage (three true leaves) resulted in considerable inhibition of the growth of the upper uninfected distal leaves; the length of leaf blade and leaf sheath of the sixth and seventh leaf was reduced by 27 and 82%, and 88 and 72%, respectively, compared to that in the uninoculated plant control. Interestingly, cutting off the blast-infected fourth leaf blade within 2 days post inoculation (dpi) significantly rescued the inhibition of leaf growth, implying that an inhibitory substance(s) and/or signal was generated in the blast-infected leaves (fourth leaf) and transmitted to the upper distal leaves (sixth and seventh) during the 2-dpi period that induced growth inhibition. Expression analysis of marker genes for phytohormone pathways revealed acute activation of the jasmonate (JA) and abscisic acid (ABA) signaling pathways, and repression of auxin, gibberellic acid (GA) and salicylic acid (SA) signaling pathways, in the sixth leaf. The genes related to cell wall expansion were also significantly downregulated. In the blast-infected fourth leaf, JA pathway was activated within 2 dpi, followed by activation of ABA pathway 3 dpi. Further, leaf inhibition caused by blast infection was partially rescued in the rice mutant line coleoptile photomorphogenesis 2 (cpm2), which is defective in the gene encoding allene oxide cyclase (OsAOC). These results indicate that the JA signaling pathway is at least partly involved in the growth inhibition processes. Collectively, our data suggest that, upon pathogen attack, rice seedlings prioritize defense reactions against the infecting pathogen by temporarily ceasing plant

  2. The L-type Ca2+ Channel Blocker Nifedipine Inhibits Mycelial Growth, Sporulation, and Virulence of Phytophthora capsici

    PubMed Central

    Liu, Peiqing; Gong, Jie; Ding, Xueling; Jiang, Yue; Chen, Guoliang; Li, Benjin; Weng, Qiyong; Chen, Qinghe

    2016-01-01

    The oomycete vegetable pathogen Phytophthora capsici causes significant losses of important vegetable crops worldwide. Calcium and other plant nutrients have been used in disease management of oomycete pathogens. Calcium homeostasis and signaling is essential for numerous biological processes, and Ca2+ channel blockers prevent excessive Ca2+ influx into the fungal cell. However, it is not known whether voltage-gated Ca2+ channel blockers improve control over oomycete pathogens. In the present study, we compared the inhibitory effects of CaCl2 and the extracellular Ca2+ chelator EDTA on mycelial growth and found that calcium assimilation plays a key role in P. capsici mycelial growth. Next, we involved the voltage-gated Ca2+ channel blockers verapamil (VP) and nifedipine (NFD) to analyze the effect of Ca2+ channel blockers on mycelial growth and sporulation; the results suggested that NFD, but not VP, caused significant inhibition. Ion rescue in an NFD-induced inhibition assay suggested that NFD-induced inhibition is calcium-dependent. In addition, NFD increased P. capsici sensitivity to H2O2 in a calcium-dependent manner, and extracellular calcium rescued it. Furthermore, NFD inhibited the virulence and gene expression related to its pathogenicity. These results suggest that NFD inhibits mycelial growth, sporulation, and virulence of P. capsici. PMID:27540377

  3. α-Pinene Inhibits Growth and Induces Oxidative Stress in Roots

    PubMed Central

    SINGH, HARMINDER P.; BATISH, DAIZY R.; KAUR, SHALINDER; ARORA, KOMAL; KOHLI, RAVINDER K.

    2006-01-01

    • Background and Aims Determining the mode of action of allelochemicals is one of the challenging aspects in allelopathic studies. Recently, allelochemicals have been proposed to cause oxidative stress in target tissue and induce an antioxidant mechanism. α-Pinene, one of the common monoterpenoids emitted from several aromatic plants including forest trees, is known for its growth-inhibitory activity. However, its mechanism of action remains unexplored. The aim of the present study was to determine the inhibitory effect of α-pinene on root growth and generation of reactive oxygen species, as indicators of oxidative stress and changes in activities of antioxidant enzymes. • Methods Effects of α-pinene on early root growth were studied in five test species, Cassia occidentalis, Amaranthus viridis, Triticum aestivum, Pisum sativum and Cicer arietinum. Electrolyte leakage, lipid peroxidation, hydrogen peroxide generation, proline accumulation, and activities of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR) were studied in roots of C. occidentalis. • Key Results α-Pinene inhibited the radicle growth of all the test species. Exposure of C. occidentalis roots to α-pinene enhanced solute leakage, and increased levels of malondialdehyde, proline and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, GPX, APX and GR were significantly elevated, thereby indicating the enhanced generation of reactive oxygen species (ROS) upon α-pinene exposure. Increased levels of scavenging enzymes indicates their induction as a secondary defence mechanism in response to α-pinene. • Conclusions It is concluded that α-pinene inhibits early root growth and causes oxidative damage in root tissue through enhanced generation of ROS, as indicated by increased lipid peroxidation, disruption of membrane

  4. Inhibition of crystallization caused by Proteus mirabilis during the development of infectious urolithiasis by various phenolic substances.

    PubMed

    Torzewska, Agnieszka; Rozalski, Antoni

    2014-01-01

    Infectious urolithiasis is a consequence of persistent urinary tract infections caused by urease producing bacteria e.g. Proteus mirabilis. These stones are composed of struvite and carbonate apatite. Their rapid growth and high recurrence indicate that so far appropriate methods of treatment have not been found. In the present study, the inhibitory effect of phenolic compounds was investigated in vitro against formation of struvite/apatite crystals. The impact of these substances with different chemical structures on crystallization caused by clinical isolates of P. mirabilis was tested spectrophotometrically using a microdilution method. Among the 11 tested compounds resveratrol, epigallocatechin gallate, peralgonidin, vanillic and coffee acids at the concentrations 250-1000 μg/ml inhibited P. mirabilis urease activity and crystallization. However, only vanillic acid had such an effect on all tested strains of P. mirabilis. Therefore, using an in vitro model, bacterial growth, crystallization, urease activity and pH were examined for 24h in synthetic urine with vanillic acid. Effect of vanillic acid was compared with that of other known struvite/apatite crystallization inhibitors (acetohydroxamic acid, pyrophosphate) and it was shown that vanillic acid strongly inhibited bacterial growth and the formation of crystals. It can be assumed that this compound, after further studies, can be used in the treatment or prophylaxis of infectious urolithiasis.

  5. Combined MET inhibition and topoisomerase I inhibition block cell growth of small cell lung cancer.

    PubMed

    Rolle, Cleo E; Kanteti, Rajani; Surati, Mosmi; Nandi, Suvobroto; Dhanasingh, Immanuel; Yala, Soheil; Tretiakova, Maria; Arif, Qudsia; Hembrough, Todd; Brand, Toni M; Wheeler, Deric L; Husain, Aliya N; Vokes, Everett E; Bharti, Ajit; Salgia, Ravi

    2014-03-01

    Small cell lung cancer (SCLC) is a devastating disease, and current therapies have not greatly improved the 5-year survival rates. Topoisomerase (Top) inhibition is a treatment modality for SCLC; however, the response is short lived. Consequently, our research has focused on improving SCLC therapeutics through the identification of novel targets. Previously, we identified MNNG HOS transforming gene (MET) to be overexpressed and functional in SCLC. Herein, we investigated the therapeutic potential of combinatorial targeting of MET using SU11274 and Top1 using 7-ethyl-10-hydroxycamptothecin (SN-38). MET and TOP1 gene copy numbers and protein expression were determined in 29 patients with limited (n = 11) and extensive (n = 18) disease. MET gene copy number was significantly increased (>6 copies) in extensive disease compared with limited disease (P = 0.015). Similar TOP1 gene copy numbers were detected in limited and extensive disease. Immunohistochemical staining revealed a significantly higher Top1 nuclear expression in extensive (0.93) versus limited (0.15) disease (P = 0.04). Interestingly, a significant positive correlation was detected between MET gene copy number and Top1 nuclear expression (r = 0.5). In vitro stimulation of H82 cells revealed hepatocyte growth factor (HGF)-induced nuclear colocalization of p-MET and Top1. Furthermore, activation of the HGF/MET axis enhanced Top1 activity, which was abrogated by SU11274. Combination of SN-38 with SU11274 dramatically decreased SCLC growth as compared with either drug alone. Collectively, these findings suggest that the combinatorial inhibition of MET and Top1 is a potentially efficacious treatment strategy for SCLC. ©2013 AACR.

  6. Inhibition of endoglin-GIPC interaction inhibits pancreatic cancer cell growth

    PubMed Central

    Pal, Krishnendu; Pletnev, Alexandre A.; Dutta, Shamit K.; Wang, Enfeng; Zhao, Ruizhi; Baral, Aradhita; Yadav, Vinod Kumar; Aggarwal, Suruchi; Krishnaswamy, Soundararajan; Alkharfy, Khalid M.; Chowdhury, Shantanu; Spaller, Mark R.; Mukhopadhyay, Debabrata

    2014-01-01

    Endoglin, a 180 kDa disulfide-linked homodimeric, transmembrane receptor protein mostly expressed in tumor-associated endothelial cells, is an endogenous binding partner of GAIP-interacting protein, C terminus (GIPC). Endoglin functions as a co-receptor of TβRII that binds Transforming Growth Factor-β (TGF-β) and is important for vascular development, and consequently has become a compelling target for anti-angiogenic therapies. A few recent studies in Gastrointestinal Stromal Tumor (GIST), breast cancer and ovarian cancer, however, suggest that endoglin is upregulated in tumor cells and is associated with poor prognosis. These findings indicate a broader role of endoglin in tumor biology, beyond anti-angiogenic effects. The goal of our current study is to evaluate the effects of targeting endoglin in pancreatic cancer both in vitro and in vivo. We analyzed the anti-proliferative effect of both RNAi-based and peptide ligand-based inhibition of endoglin in pancreatic cancer cell lines, the latter yielding a GIPC PDZ domain-targeting lipopeptide with notable anti-proliferative activity. We further demonstrated that endoglin inhibition induced a differentiation phenotype in the pancreatic cancer cells and sensitized them against conventional chemotherapeutic drug gemcitabine. Most importantly, we have demonstrated the anti-tumor effect of both RNAi based and competitive inhibitor based blocking of endoglin in pancreatic cancer xenograft models in vivo. To our knowledge, this is the first report exploring the effect of targeting endoglin in pancreatic cancer cells. PMID:25125675

  7. Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation.

    PubMed

    Bennett, Darin C; Leung, Gigi; Wang, Eddy; Ma, Sam; Lo, Blanche K K; McElwee, Kevin J; Cheng, Kimberly M

    2015-09-01

    Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51×faster), ostrich oil (1.46×faster), and rhea oil (1.64×faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35×slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions.

  8. Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation

    PubMed Central

    Bennett, Darin C.; Leung, Gigi; Wang, Eddy; Ma, Sam; Lo, Blanche K. K.; McElwee, Kevin J.; Cheng, Kimberly M.

    2015-01-01

    Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51 × faster), ostrich oil (1.46 × faster), and rhea oil (1.64 × faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35 × slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions. PMID:26217022

  9. Mutation of a single lytic transglycosylase causes aberrant septation and inhibits cell separation of Neisseria gonorrhoeae.

    PubMed

    Cloud, Karen A; Dillard, Joseph P

    2004-11-01

    The function of lytic peptidoglycan transglycosylases is poorly understood. Single lytic transglycosylase mutants of Escherichia coli have no growth phenotype. By contrast, mutation of Neisseria gonorrhoeae ltgC inhibited cell separation without affecting peptidoglycan monomer production. Thus, LtgC has a dedicated function in gonococcal cell division.

  10. Benzylidene Acylhydrazides Inhibit Chlamydial Growth in a Type III Secretion- and Iron Chelation-Independent Manner

    PubMed Central

    Bao, Xiaofeng; Gylfe, Åsa; Sturdevant, Gail L.; Gong, Zheng; Xu, Shuang; Caldwell, Harlan D.; Elofsson, Mikael

    2014-01-01

    Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection. However, these inhibitors also have the capacity to chelate iron, and it is possible that their antichlamydial effects are caused by iron starvation. Therefore, we have explored the modification of salicylidene acylhydrazides with the goal to uncouple the antichlamydial effect from iron starvation. We discovered that benzylidene acylhydrazides, which cannot chelate iron, inhibit chlamydial growth. Biochemical and genetic analyses suggest that the derivative compounds inhibit chlamydiae through a T3SS-independent mechanism. Four single nucleotide polymorphisms were identified in a Chlamydia muridarum variant resistant to benzylidene acylhydrazides, but it may be necessary to segregate the mutations to differentiate their roles in the resistance phenotype. Benzylidene acylhydrazides are well tolerated by host cells and probiotic vaginal Lactobacillus species and are therefore of potential therapeutic value. PMID:24914180

  11. Suppression of polymorphonuclear (PMN) and monocyte-mediated inhibition of Candida albicans growth by delta-9-tetrahydrocannabinol

    SciTech Connect

    Djeu, J.Y.; Parapanios, A.; Halkias, D.; Friedman, H.

    1986-03-05

    This study was an in vitro attempt to identify the effector cells responsible for growth inhibition of the opportunistic fungus, candida albicans, and to determine if THC or another marijuana derivatives, 11-hydroxyTHC, would adversely affect their function. Using a 24h radiolabel assay, the authors found that growth inhibition of C. albicans was primarily mediated by PMN and monocytes that could be isolated normal human peripheral blood. Both effector cell types caused almost complete inhibition of Candida growth at effector/target ratio of 300/1 and inhibition was often still seen at 30/1-. Incubation of PMN, PBL, or monocytes for 1 hr at 37C with THC or 11-hydroxyTHC caused a marked suppression of function in all 3 cell populations. Maximal suppression was obtained with 7.5-10..mu..g/ml of the drugs in medium containing 10% fetal bovine serum (FBS) or with 2-4..mu..g/ml in 1% FBS. These drug concentrations did not affect lymphoid cell viability or candida growth in the absence of lymphoid effector cells. Marijuana derivatives, therefore, are doubly dangerous in that opportunistic fungi such as C. albicans can grow in their presence while the effector cells that control fungal growth are readily inactivated.

  12. Quercetin inhibits angiogenesis-mediated human retinoblastoma growth by targeting vascular endothelial growth factor receptor.

    PubMed

    Song, Wei; Zhao, Xiaofei; Xu, Jiarui; Zhang, Han

    2017-09-01

    Retinoblastoma (RB) is the most common malignant intraocular cancer in teenagers, occurrence of which depends on the mutation of multiple genes. Among all the signaling pathways involved in the oncogenesis of RB, the process of angiogenesis has been demonstrated to be associated with the local invasive growth and metastasis of this cancer type. Quercetin (Que) is a typical flavonoid and has been reported to inhibit angiogenesis in various types of tumors. In the present study, the effect of Que on RB cells and angiogenesis of RB was evaluated. The human RB Y79 cell line was subjected to treatment with Que of various concentrations. Viability, invasion and migration ability and apoptosis of Y79 cells were subsequently measured to assess the effect of Que on RB cells. In addition, the expression of vascular endothelial growth factor receptor (VEGFR) was also quantified. It was revealed that Que inhibited RB cell growth and invasion in vitro in a dose-dependent manner, with 100 µM Que exhibiting the strongest inhibitory effect. In addition, Que downregulated the expression of VEGFR, which was an indicator of the blockade of angiogenesis in RB by targeting VEGF. The effect of Que on angiogenesis was also observed to be dose-dependent. The results of the present study indicated that Que may be a potential anti-RB therapy due to its anti-angiogenesis effect.

  13. MECHANISMS OF FLUID SHEAR-INDUCED INHIBITION OF POPULATION GROWTH IN A RED-TIDE DINOFLAGELLATE

    EPA Science Inventory

    Net population growth of some dinoflagellates is inhibited by fluid shear at shear stresses comparable with those generated during oceanic turbulence. Decreased net growth may occur through lowered cell division, increased mortality, or both. The dominant mechanism under various ...

  14. MECHANISMS OF FLUID SHEAR-INDUCED INHIBITION OF POPULATION GROWTH IN A RED-TIDE DINOFLAGELLATE

    EPA Science Inventory

    Net population growth of some dinoflagellates is inhibited by fluid shear at shear stresses comparable with those generated during oceanic turbulence. Decreased net growth may occur through lowered cell division, increased mortality, or both. The dominant mechanism under various ...

  15. Growth kinetics and inhibition of growth of chemical vapor deposited thin tungsten films on silicon from tungsten hexafluoride

    NASA Astrophysics Data System (ADS)

    Leusink, G. J.; Kleijn, C. R.; Oosterlaken, T. G. M.; Janssen, G. C. A. M.; Radelaar, S.

    1992-07-01

    The growth kinetics and inhibition of growth of chemical vapor deposited thin W films on Si(100) from WF6 was studied with in situ growth stress and reflectivity measurements and ex situ weight gain measurements. A systematic series of experiments at varying WF6 flow, total pressure, and temperature show that the thickening kinetics and inhibition of the growth are controlled by two processes: WF6 diffusion through the gas phase and Si diffusion through the thickening columnar film. The steady state growth kinetics are controlled by WF6 diffusion in the gas phase whereas inhibition of the growth occurs at the transition from WF6 gas diffusion limited to Si solid state diffusion limited growth. A simple model based on WF6 gas phase diffusion and Si solid state diffusion is presented which gives a quantitative description of the experimental results.

  16. Methyl-donor nutrients inhibit breast cancer cell growth.

    PubMed

    Park, Chung S; Cho, Kyongshin; Bae, Dong R; Joo, Nam E; Kim, Hyung H; Mabasa, Lawrence; Fowler, Andrea W

    2008-01-01

    Lipotropes (methyl group containing nutrients, including methionine, choline, folate, and vitamin B(12)) are dietary methyl donors and cofactors that are involved in one-carbon metabolism, which is important for genomic DNA methylation reactions and nucleic acid synthesis. One-carbon metabolism provides methyl groups for all biological methylation pathways and is highly dependent on dietary supplementation of methyl nutrients. Nutrition is an important determinant of breast cancer risk and tumor behavior, and dietary intervention may be an effective approach to prevent breast cancer. Apoptosis is important for the regulation of homeostasis and tumorigenesis. The anti-apoptotic protein Bcl-2 may be a regulatory target in cancer therapy; controlling or modulating its expression may be a therapeutic strategy against breast cancer. In this study, the effects of lipotrope supplementation on the growth and death of human breast cancer cell lines T47D and MCF-7 were examined and found to inhibit growth of both T47D and MCF-7 cells. Furthermore, the ratios of apoptotic cells to the total number of cells were approximately 44% and 34% higher in the lipotrope-supplemented treatments of T47D and MCF-7 cancer cells, respectively, compared with the control treatments. More importantly, Bcl-2 protein expression was decreased by approximately 25% from lipotrope supplementation in T47D cells, suggesting that lipotropes can induce breast cancer cell death by direct downregulation of Bcl-2 protein expression. Cancer treatment failure is often correlated with Bcl-2 protein upregulation. These data may be useful in the development of effective nutritional strategies to prevent and reduce breast cancer in humans.

  17. AP-2α inhibits hepatocellular carcinoma cell growth and migration.

    PubMed

    Huang, Wenhuan; Chen, Cheng; Liang, Zhongheng; Qiu, Junlu; Li, Xinxin; Hu, Xiang; Xiang, Shuanglin; Ding, Xiaofeng; Zhang, Jian

    2016-03-01

    Transcription factor AP-2α is involved in many types of human cancers, but its role in hepatocellular carcinogenesis is largely unknown. In this study, we found that expression of AP-2α was low in 40% of human hepatocellular cancers compared with adjacent normal tissues by immunohistochemical analysis. Moreover, AP-2α expression was low or absent in hepatocellular cancer cell lines (HepG2, Hep3B, SMMC-7721 and MHHC 97-H). Human liver cancer cell lines SMMC-7721 and Hep3B stably overexpressing AP-2α were established by lentiviral infection and puromycin screening, and the ectopic expression of AP-2α was able to inhibit hepatocellular cancer cell growth and proliferation by cell viability, MTT assay and liquid colony formation in vitro and in vivo. Furthermore, AP-2α overexpression decreased liver cancer cell migration and invasion as assessed by wound healing and Transwell assays, increasing the sensitivity of liver cancer cells to cisplatin analyzed by MTT assays. Also AP-2α overexpression suppressed the sphere formation and renewed the ability of cancer stem cells. Finally, we found that AP-2α is epigenetically modified and modulates the levels of phosphorylated extracellular signal-regulated protein kinase (ERK), β-catenin, p53, EMT, and CD133 expression in liver cancer cell lines. These results suggested that AP-2α expression is low in human hepatocellular cancers by regulating multiple signaling to affect hepatocellular cancer cell growth and migration. Therefore, AP-2α might represent a novel potential target in human hepatocellular cancer therapy.

  18. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes

    PubMed Central

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration. PMID:28184354

  19. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes.

    PubMed

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration.

  20. A Novel Sulindac Derivative That Does Not Inhibit Cyclooxygenases but Potently Inhibits Colon Tumor Cell Growth and Induces Apoptosis with Antitumor Activity

    PubMed Central

    Piazza, Gary A.; Keeton, Adam B.; Tinsley, Heather N.; Gary, Bernard D.; Whitt, Jason D.; Mathew, Bini; Thaiparambil, Jose; Coward, Lori; Gorman, Gregory; Li, Yonghe; Sani, Brahma; Hobrath, Judith V.; Maxuitenko, Yulia Y.; Reynolds, Robert C.

    2011-01-01

    Nonsteroidal anti-inflammatory drugs such as sulindac have shown promising antineoplastic activity, although toxicity from cyclooxygenase (COX) inhibition and the suppression of prostaglandin synthesis limits their use for chemoprevention. Previous studies have concluded that the mechanism responsible for their antineoplastic activity may be COX independent. To selectively design out the COX inhibitory activity of sulindac sulfide (SS), in silico modeling studies were done that revealed the crucial role of the carboxylate moiety for COX-1 and COX-2 binding. These studies prompted the synthesis of a series of SS derivatives with carboxylate modifications that were screened for tumor cell growth and COX inhibitory activity. A SS amide (SSA) with a N,N-dimethylethyl amine substitution was found to lack COX-1 and COX-2 inhibitory activity, yet potently inhibit the growth of human colon tumor cell lines, HT-29, SW480, and HCT116 with IC50 values of 2 to 5 µmol/L compared with 73 to 85 µmol/L for SS. The mechanism of growth inhibition involved the suppression of DNA synthesis and apoptosis induction. Oral administration of SSA was well-tolerated in mice and generated plasma levels that exceeded its in vitro IC50 for tumor growth inhibition. In the human HT-29 colon tumor xenograft mouse model, SSA significantly inhibited tumor growth at a dosage of 250 mg/kg. Combined treatment of SSA with the chemotherapeutic drug, Camptosar, caused a more sustained suppression of tumor growth compared with Camptosar treatment alone. These results indicate that SSA has potential safety and efficacy advantages for colon cancer chemoprevention as well as utility for treating malignant disease if combined with chemotherapy. PMID:19470791

  1. A novel sulindac derivative that does not inhibit cyclooxygenases but potently inhibits colon tumor cell growth and induces apoptosis with antitumor activity.

    PubMed

    Piazza, Gary A; Keeton, Adam B; Tinsley, Heather N; Gary, Bernard D; Whitt, Jason D; Mathew, Bini; Thaiparambil, Jose; Coward, Lori; Gorman, Gregory; Li, Yonghe; Sani, Brahma; Hobrath, Judith V; Maxuitenko, Yulia Y; Reynolds, Robert C

    2009-06-01

    Nonsteroidal anti-inflammatory drugs such as sulindac have shown promising antineoplastic activity, although toxicity from cyclooxygenase (COX) inhibition and the suppression of prostaglandin synthesis limits their use for chemoprevention. Previous studies have concluded that the mechanism responsible for their antineoplastic activity may be COX independent. To selectively design out the COX inhibitory activity of sulindac sulfide (SS), in silico modeling studies were done that revealed the crucial role of the carboxylate moiety for COX-1 and COX-2 binding. These studies prompted the synthesis of a series of SS derivatives with carboxylate modifications that were screened for tumor cell growth and COX inhibitory activity. A SS amide (SSA) with a N,N-dimethylethyl amine substitution was found to lack COX-1 and COX-2 inhibitory activity, yet potently inhibit the growth of human colon tumor cell lines, HT-29, SW480, and HCT116 with IC(50) values of 2 to 5 micromol/L compared with 73 to 85 micromol/L for SS. The mechanism of growth inhibition involved the suppression of DNA synthesis and apoptosis induction. Oral administration of SSA was well-tolerated in mice and generated plasma levels that exceeded its in vitro IC(50) for tumor growth inhibition. In the human HT-29 colon tumor xenograft mouse model, SSA significantly inhibited tumor growth at a dosage of 250 mg/kg. Combined treatment of SSA with the chemotherapeutic drug, Camptosar, caused a more sustained suppression of tumor growth compared with Camptosar treatment alone. These results indicate that SSA has potential safety and efficacy advantages for colon cancer chemoprevention as well as utility for treating malignant disease if combined with chemotherapy.

  2. Growth of Streptomyces Hygroscopicus in Rotating-Wall Bioreactor Under Simulated Microgravity Inhibits Rapamycin Production

    NASA Technical Reports Server (NTRS)

    Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.

    2000-01-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  3. Growth of Steptomyces hygroscopicus in rotating-wall bioreactor under simulated microgravity inhibits rapamycin production.

    PubMed

    Fang, A; Pierson, D L; Mishra, S K; Demain, A L

    2000-07-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin, in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  4. Growth of Steptomyces hygroscopicus in rotating-wall bioreactor under simulated microgravity inhibits rapamycin production

    NASA Technical Reports Server (NTRS)

    Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.

    2000-01-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin, in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  5. Growth of Steptomyces hygroscopicus in rotating-wall bioreactor under simulated microgravity inhibits rapamycin production

    NASA Technical Reports Server (NTRS)

    Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.

    2000-01-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin, in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  6. Characterization of growth inhibition of oral bacteria by sophorolipid using a microplate-format assay.

    PubMed

    Solaiman, Daniel K Y; Ashby, Richard D; Uknalis, Joseph

    2017-05-01

    Sophorolipid (SL) is a class of glycolipid biosurfactant produced by yeast and has potent antimicrobial activity against many microorganisms. In this paper, a microplate-based method was developed to characterize the growth inhibition by SL on five representative species of caries-causing oral bacteria. Bacterial growth on microplate in the absence and presence of varying concentrations of SL was continuously monitored by recording the absorbance at 600nm of the cultures using a microplate reader. The results showed that SL completely inhibited the growth of the Lactobacilli at ≥1mg/ml and the Streptococci at much lower concentrations of ≥50μg/ml. More importantly, we further defined the mechanism of antimicrobial activity of SL by analyzing the pattern of the cell growth curves. SL at sublethal concentrations (<1mg/ml) is bactericidal towards the Lactobacilli; it lengthens the apparent cell-doubling time (Td) and decreases the final cell density (as indicated by A600nm) in a concentration-dependent manner. Against the oral Streptococci, on the other hand, SL at sublethal concentrations (<50μg/ml) is bacteriostatic; it delays the onset of cell growth in a concentration-dependent fashion, but once the cell growth is commenced there is no noticeable adverse effect on Td and the final A600nm. Scanning electron microscopic (SEM) study of L. acidophilus grown in sublethal concentration of SL reveals extensive structural damage to the cells. S. mutans grown in sublethal level of SL did not show morphological damage to the cells, but numerous protruding structures could be seen on the cell surface. At the respective lethal levels of SL, L. acidophilus cells were lysed (at 1mg/ml SL) and the cell surface structure of S. mutans (at 130μg/ml SL) was extensively deformed. In summary, this paper presents the first report on a detailed analysis of the effects of SL on Lactobacilli and Streptococci important to oral health and hygiene.

  7. Trophosome of the Deep-Sea Tubeworm Riftia pachyptila Inhibits Bacterial Growth

    PubMed Central

    Klose, Julia; Aistleitner, Karin; Horn, Matthias; Krenn, Liselotte; Dirsch, Verena; Zehl, Martin; Bright, Monika

    2016-01-01

    The giant tubeworm Riftia pachyptila lives in symbiosis with the chemoautotrophic gammaproteobacterium Cand. Endoriftia persephone. Symbionts are released back into the environment upon host death in high-pressure experiments, while microbial fouling is not involved in trophosome degradation. Therefore, we examined the antimicrobial effect of the tubeworm’s trophosome and skin. The growth of all four tested Gram-positive, but only of one of the tested Gram-negative bacterial strains was inhibited by freshly fixed and degrading trophosome (incubated up to ten days at either warm or cold temperature), while no effect on Saccharomyces cerevisiae was observed. The skin did not show antimicrobial effects. A liquid chromatography-mass spectrometric analysis of the ethanol supernatant of fixed trophosomes lead to the tentative identification of the phospholipids 1-palmitoleyl-2-lyso-phosphatidylethanolamine, 2-palmitoleyl-1-lyso-phosphatidylethanolamine and the free fatty acids palmitoleic, palmitic and oleic acid, which are known to have an antimicrobial effect. As a result of tissue autolysis, the abundance of the free fatty acids increased with longer incubation time of trophosome samples. This correlated with an increasing growth inhibition of Bacillus subtilis and Listeria welshimeri, but not of the other bacterial strains. Therefore, the free fatty acids produced upon host degradation could be the cause of inhibition of at least these two bacterial strains. PMID:26730960

  8. Silencing of ATF2 inhibits growth of pancreatic cancer cells and enhances sensitivity to chemotherapy.

    PubMed

    Li, Mu; Wu, Xingda; Liu, Ning; Li, Xiaoying; Meng, Fanbin; Song, Shaowei

    2017-03-20

    Pancreatic cancer is one of the leading causes of cancer-related death worldwide. Activating transcription factor 2 (ATF2) is a multifunctional transcription factor, and is implicated in tumor progress, yet its role in pancreatic cancer remains unclear. In the present study, the level of ATF2 in pancreatic cancer tissues and the adjacent non-tumorous tissues was detected by quantitative real-time PCR and western blot. The roles of ATF2 in the proliferation, cell cycle, and apoptosis of pancreatic cancer cells were investigated through ATF2 silencing, and the effect of ATF2 shRNA on the sensitivity of pancreatic cancer cells to gemcitabine, an anti-tumor drug, was explored. The results of our study showed that the ATF2 level in the pancreatic cancer tissues was higher than that in the adjacent non-tumorous tissues. Silencing of ATF2 was found to inhibit proliferation, arrest cell cycle at G1 phase and induce apoptosis in pancreatic cancer cells. Moreover, ATF2 silencing enhanced gemcitabine-induced growth-inhibition and apoptosis-induction effects in pancreatic cancer cells. In summary, silencing of ATF2 inhibited the growth of pancreatic cancer cells and enhanced the anti-tumor effects of gemcitabine, suggesting that ATF2 plays a pro-survival role in pancreatic cancer. Our results also propose that a high level of ATF2 may serve as a potential biomarker of pancreatic cancer, and that ATF2 may become a potential target for anti-tumor therapy.

  9. Trophosome of the Deep-Sea Tubeworm Riftia pachyptila Inhibits Bacterial Growth.

    PubMed

    Klose, Julia; Aistleitner, Karin; Horn, Matthias; Krenn, Liselotte; Dirsch, Verena; Zehl, Martin; Bright, Monika

    2016-01-01

    The giant tubeworm Riftia pachyptila lives in symbiosis with the chemoautotrophic gammaproteobacterium Cand. Endoriftia persephone. Symbionts are released back into the environment upon host death in high-pressure experiments, while microbial fouling is not involved in trophosome degradation. Therefore, we examined the antimicrobial effect of the tubeworm's trophosome and skin. The growth of all four tested Gram-positive, but only of one of the tested Gram-negative bacterial strains was inhibited by freshly fixed and degrading trophosome (incubated up to ten days at either warm or cold temperature), while no effect on Saccharomyces cerevisiae was observed. The skin did not show antimicrobial effects. A liquid chromatography-mass spectrometric analysis of the ethanol supernatant of fixed trophosomes lead to the tentative identification of the phospholipids 1-palmitoleyl-2-lyso-phosphatidylethanolamine, 2-palmitoleyl-1-lyso-phosphatidylethanolamine and the free fatty acids palmitoleic, palmitic and oleic acid, which are known to have an antimicrobial effect. As a result of tissue autolysis, the abundance of the free fatty acids increased with longer incubation time of trophosome samples. This correlated with an increasing growth inhibition of Bacillus subtilis and Listeria welshimeri, but not of the other bacterial strains. Therefore, the free fatty acids produced upon host degradation could be the cause of inhibition of at least these two bacterial strains.

  10. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    NASA Astrophysics Data System (ADS)

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; Dewitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-10-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models.

  11. Triiodothyronine inhibits transcription from the human growth hormone promoter.

    PubMed

    Morin, A; Louette, J; Voz, M L; Tixier-Vidal, A; Belayew, A; Martial, J A

    1990-07-09

    Three DNA constructs, the natural human growth hormone gene (hGH-hGH) its 500 bp promoter linked to the chloramphenicol acetyl transferase reporter gene (hGH-CAT), and its structural part linked to the herpes virus thymidine kinase promoter (TK-hGH) were introduced into rat pituitary GC cells by DEAE-dextran transfection. Transient expression was followed as a function of triiodothyronine (T3) concentration. The hGH-CAT expression was specifically inhibited by T3 following a typical dose-response curve while hGH-GH gene expression was not significantly modified. The transient expression of TK-hGH increased as a function of T3 concentration. These results indicate that T3 exerts two opposite effects on hGH gene expression. First, it down-regulates expression by acting on the promoter; second, it up-regulates expression by acting on the structural part of the gene. These action could be due to regulation of transcription and mRNA stabilization, respectively.

  12. Soaking salted eggs in gambier liquid waste inhibit bacterial growth.

    PubMed

    Novia, Deni; Juliyarsi, Indri; Sandra, Afriani; Dan, Yuherman; Muhammad, Rifki

    2014-02-01

    Gambier liquid waste containing tannin compounds were quite high and serves as an antimicrobial agent that will tanning salted eggs so that closed the pores of the egg shell and egg to be durable. This study aims to see the effect of soaking salted eggs in gambier liquid waste remaining effective in improving the quality of salted eggs. This study used a randomized block design with three replicates and ten treatments. The treatment were, A: control (no soaking), B: Immersion 49 h with a gambier liquid waste : distilled water (1:2), C: 25 h (1:2), D: 1 h (1:2), E: 49 h (1:1), F:25 h (1:1), G: 1 h (1:1), H: 49 h (1:0), I: 25 h (1:0), J: 1 h (1:0). The variables used were water content, bacterial colony forming and shelf life. Results of this study showed a significant (p < 0.05) on water content, bacterial colony forming and shelf life. The best treatment inhibiting bacterial growth for longer was salted eggs soaking in gambier liquid waste : water (1:0) 1 h and 25 h with a water content of 62.67%, bacterial colony forming 0.99 x 1 (0)5 CFU (g-1) and a shelf life 63 days.

  13. Short photoperiod inhibits winter growth of subtropical grasses.

    PubMed

    Sinclair, T R; Mislevy, P; Ray, J D

    2001-07-01

    Grass development is influenced by length of photoperiod, but no direct measurements under natural conditions exist on mass accumulation in response to photoperiod by subtropical grass species. Grasslands of the subtropics are a major resource, but their growth is inhibited substantially during the short-photoperiod months. This research was designed to examine the consequences on grass production under field conditions when the limitation of short photoperiod is artificially removed. Lights, which extended the daylength to 15 h, were placed over plots of four subtropical forage grasses representing three species (Paspalum notatum Flugge; Cynodon dactylon L.; Cynodon nlemfuensis Vanderyst) to measure their mass accumulation in response to extended photoperiod in a 2-year experiment. Forage yields in all grasses at 5-week harvests during the time of shortest daylength were increased up to 6.2-fold more than the yield under the natural daylength. For the 4.5-month period of shortest daylength in each year, forage yields were increased for all grasses with one grass having a yield increase of 3.6-fold under the extended photoperiod as compared to natural daylength. These results demonstrated that selection of grasses that are insensitive to photoperiod could substantially increase forage yield of subtropical grasslands to benefit animal production and enhance carbon sequestration.

  14. Self-inhibiting growth of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Langen, P. L.; Solgaard, A. M.; Hvidberg, C. S.

    2012-04-01

    The build-up of the Greenland Ice Sheet from ice free conditions is studied in an ice sheet model (ISM) driven by fields from an atmospheric general circulation model (GCM). Experiments where the two are coupled offline are performed and augmented by one where an intermediate ice sheet configuration, taken as a snap shot during the regrowth in the ISM, is coupled back to the GCM. It is found that several open questions regarding reversibility or irreversibility of a disintegration of the Greenland Ice Sheet may be reconciled with these experiments. Running the ISM with GCM fields corresponding to a present day ice sheet configuration leads to regrowth, while considerations of the GCM's snow accumulation in an ice free run point to irreversibility. Forcing the ISM with the GCM fields corresponding to the ice free state leads to extensive regrowth which, however, is halted when an intermediate recoupling step is included. This inhibition of further growth is believed to be due to a Föhn effect of moist air parcels being lifted over the intermediate ice sheet and arriving in the Greenland interior with high temperatures.

  15. Self-inhibiting growth of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Langen, P. L.; Solgaard, A. M.; Hvidberg, C. S.

    2012-06-01

    The build-up of the Greenland Ice Sheet (GrIS) from ice-free conditions is studied in an ice sheet model (ISM) driven by fields from an atmospheric general circulation model (GCM) to demonstrate the importance of coupling between the two components. Experiments where the two are coupled off-line are augmented by one where an intermediate ice sheet configuration is coupled back to the GCM. Forcing the ISM with GCM fields corresponding to the ice-free state leads to extensive regrowth which, however, is halted when the intermediate recoupling step is included. This inhibition of further growth is due to a Föhn effect of moist air parcels being lifted over the intermediate ice sheet and arriving in the low-lying Greenland interior with high temperatures. This demonstrates that two-way coupling between the atmosphere and the ice sheet is essential for understanding the dynamics and that large scale conditions cooler than those of today may be necessary for the GrIS to regrow to the present volume.

  16. Growth Hormone Inhibits Hepatic De Novo Lipogenesis in Adult Mice

    PubMed Central

    Cordoba-Chacon, Jose; Majumdar, Neena; List, Edward O.; Diaz-Ruiz, Alberto; Frank, Stuart J.; Manzano, Anna; Bartrons, Ramon; Puchowicz, Michelle; Kopchick, John J.

    2015-01-01

    Patients with nonalcoholic fatty liver disease (NAFLD) are reported to have low growth hormone (GH) production and/or hepatic GH resistance. GH replacement can resolve the fatty liver condition in diet-induced obese rodents and in GH-deficient patients. However, it remains to be determined whether this inhibitory action of GH is due to direct regulation of hepatic lipid metabolism. Therefore, an adult-onset, hepatocyte-specific, GH receptor (GHR) knockdown (aLivGHRkd) mouse was developed to model hepatic GH resistance in humans that may occur after sexual maturation. Just 7 days after aLivGHRkd, hepatic de novo lipogenesis (DNL) was increased in male and female chow-fed mice, compared with GHR-intact littermate controls. However, hepatosteatosis developed only in male and ovariectomized female aLivGHRkd mice. The increase in DNL observed in aLivGHRkd mice was not associated with hyperactivation of the pathway by which insulin is classically considered to regulate DNL. However, glucokinase mRNA and protein levels as well as fructose-2,6-bisphosphate levels were increased in aLivGHRkd mice, suggesting that enhanced glycolysis drives DNL in the GH-resistant liver. These results demonstrate that hepatic GH actions normally serve to inhibit DNL, where loss of this inhibitory signal may explain, in part, the inappropriate increase in hepatic DNL observed in NAFLD patients. PMID:26015548

  17. Chinese medicinal herbs inhibit growth of murine renal cell carcinoma.

    PubMed

    Lau, B H; Ruckle, H C; Botolazzo, T; Lui, P D

    1994-01-01

    Tumors are known to produce factors suppressing immune functions. We previously showed that a murine renal cell carcinoma (Renca) suppressed macrophage function in vitro and that this suppression was abolished by co-incubation with extracts of two Chinese medicinal herbs. We now report that these phytochemicals are capable of inhibiting growth of Renca in vivo. BALB/c mice were transplanted intraperitoneally (IP) with 1-2 x 10(5) Renca cells. One day after tumor transplant, mice were randomized into two groups. One group was treated IP, daily for 10 days, with 100 microliters of phytochemicals containing 500 micrograms each of Astragalus membranaceus and Ligustrum lucidum, while the other group received saline as controls. A cure rate of 57% was obtained with these phytochemicals when the initial tumor load was 2 x 10(5), and 100% when the initial tumor load was 1 x 10(5). Additional experiments were performed to investigate the mechanisms involved in this protection. Splenic macrophages from tumor-bearing mice were shown to have depressed chemiluminescent oxidative burst activity, and this depression was restored with phytochemical treatment. Splenocytes from mice transplanted with Renca responded less favorably to interleukin-2 (IL-2) in generating lymphokine-activated killer (LAK) cells; again this depression was restored with phytochemical treatment. Our data suggest that these phytochemicals may have exerted their antitumor effects via augmentation of phagocyte and LAK cell activities.

  18. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth.

    PubMed

    Sano, Michael B; Arena, Christopher B; Bittleman, Katelyn R; DeWitt, Matthew R; Cho, Hyung J; Szot, Christopher S; Saur, Dieter; Cissell, James M; Robertson, John; Lee, Yong W; Davalos, Rafael V

    2015-10-13

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models.

  19. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    PubMed Central

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; DeWitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-01-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models. PMID:26459930

  20. WISP1/CCN4: A Potential Target for Inhibiting Prostate Cancer Growth and Spread to Bone

    PubMed Central

    Sonn, Robert; Kilts, Tina M.; de Castro, Luis F.; Maeda, Azusa; Fisher, Larry W.; Robey, Pamela G.; Berendsen, Agnes D.; Li, Li; McCartney-Francis, Nancy; Brown, Aaron C.; Crawford, Nigel P. S.; Molinolo, Alfredo; Jain, Alka; Fedarko, Neal S.; Young, Marian F.

    2013-01-01

    Prostate cancer (PC) is a leading cause of death in men however the factors that regulate its progression and eventual metastasis to bone remain unclear. Here we show that WISP1/CCN4 expression in prostate cancer tissues was up-regulated in early stages of the disease and, further, that it correlated with increased circulating levels of WISP1 in the sera of patients at early stages of the disease. WISP1 was also elevated in the mouse prostate cancer model TRAMP in the hypoplastic diseased tissue that develops prior to advanced carcinoma formation. When the ability of anti-WISP1 antibodies to reduce the spread of PC3-Luc cells to distant sites was tested it showed that twice weekly injections of anti-WISP1 antibodies reduced the number and overall size of distant tumors developed after intracardiac (IC) injection of PC3-Luc cells in mice. The ability of antibodies against WISP1 to inhibit growth of PC3-Luc cancer cells in mice was also evaluated and showed that twice weekly injections of anti-WISP1 antibodies reduced local tumor growth when examined in xenografts. To better understand the mechanism of action, the migration of PC3-Luc cells through membranes with or without a Matrigel™ barrier showed the cells were attracted to WISP1, and that this attraction was inhibited by treatment with anti-WISP1 antibodies. We also show the expression of WISP1 at the bone-tumor interface and in the stroma of early grade cancers suggested WISP1 expression is well placed to play roles in both fostering growth of the cancer and its spread to bone. In summary, the up-regulation of WISP1 in the early stages of cancer development coupled with its ability to inhibit spread and growth of prostate cancer cells makes it both a potential target and an accessible diagnostic marker for prostate cancer. PMID:23977121

  1. Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions

    PubMed Central

    Vergnano, Marta; Wan, Chris

    2017-01-01

    ABSTRACT We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR) inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection. PMID:28743817

  2. Inhibition of tomato shoot growth by over-irrigation is linked to nitrogen deficiency and ethylene.

    PubMed

    Fiebig, Antje; Dodd, Ian C

    2016-01-01

    Although physiological effects of acute flooding have been well studied, chronic effects of suboptimal soil aeration caused by over-irrigation of containerized plants have not, despite its likely commercial significance. By automatically scheduling irrigation according to soil moisture thresholds, effects of over-irrigation on soil properties (oxygen concentration, temperature and moisture), leaf growth, gas exchange, phytohormone [abscisic acid (ABA) and ethylene] relations and nutrient status of tomato (Solanum lycopersicum Mill. cv. Ailsa Craig) were studied. Over-irrigation slowly increased soil moisture and decreased soil oxygen concentration by 4%. Soil temperature was approximately 1°C lower in the over-irrigated substrate. Over-irrigating tomato plants for 2 weeks significantly reduced shoot height (by 25%) and fresh weight and total leaf area (by 60-70%) compared with well-drained plants. Over-irrigation did not alter stomatal conductance, leaf water potential or foliar ABA concentrations, suggesting that growth inhibition was not hydraulically regulated or dependent on stomatal closure or changes in ABA. However, over-irrigation significantly increased foliar ethylene emission. Ethylene seemed to inhibit growth, as the partially ethylene-insensitive genotype Never ripe (Nr) was much less sensitive to over-irrigation than the wild type. Over-irrigation induced significant foliar nitrogen deficiency and daily supplementation of small volumes of 10 mM Ca(NO3 )2 to over-irrigated soil restored foliar nitrogen concentrations, ethylene emission and shoot fresh weight of over-irrigated plants to control levels. Thus reduced nitrogen uptake plays an important role in inhibiting growth of over-irrigated plants, in part by stimulating foliar ethylene emission.

  3. Grape seed extract inhibits in vitro and in vivo growth of human colorectal carcinoma cells.

    PubMed

    Kaur, Manjinder; Singh, Rana P; Gu, Mallikarjuna; Agarwal, Rajesh; Agarwal, Chapla

    2006-10-15

    Accumulating evidences suggest the beneficial effects of fruit-and-vegetable consumption in lowering the risk of various cancers, including colorectal cancer. Herein, we investigated the in vitro and in vivo anticancer effects and associated mechanisms of grape seed extract (GSE), a rich source of proanthocyanidins, against colorectal cancer. Effects of GSE were examined on human colorectal cancer HT29 and LoVo cells in culture for proliferation, cell cycle progression, and apoptosis. The in vivo effect of oral GSE was examined on HT29 tumor xenograft growth in athymic nude mice. Xenografts were analyzed by immunohistochemistry for proliferation and apoptosis. The molecular changes associated with the biological effects of GSE were analyzed by Western blot analysis. GSE (25-100 microg/mL) causes a significant dose- and time-dependent inhibition of cell growth with concomitant increase in cell death. GSE induced G1 phase cell cycle arrest along with a marked increase in Cip1/p21 protein level and a decrease in G1 phase-associated cyclins and cyclin-dependent kinases. GSE-induced cell death was apoptotic and accompanied by caspase-3 activation. GSE feeding to mice at 200 mg/kg dose showed time-dependent inhibition of tumor growth without any toxicity and accounted for 44% decrease in tumor volume per mouse after 8 weeks of treatment. GSE inhibited cell proliferation but increased apoptotic cell death in tumors. GSE-treated tumors also showed enhanced Cip1/p21 protein levels and poly(ADP-ribose) polymerase cleavage. GSE may be an effective chemopreventive agent against colorectal cancer, and that growth inhibitory and apoptotic effects of GSE against colorectal cancer could be mediated via an up-regulation of Cip1/p21.

  4. The resveratrol analogue trimethoxystilbene inhibits cancer cell growth by inducing multipolar cell mitosis.

    PubMed

    Traversi, Gianandrea; Fiore, Mario; Percario, Zulema; Degrassi, Francesca; Cozzi, Renata

    2017-03-01

    Natural compounds are extensively studied for their potential use in traditional and non-traditional medicine. Several natural and synthetic Resveratrol analogues have shown interesting biological activities in the field of cancer chemoprevention. In the present study, we have focused on the ability of Resveratrol and two methoxylated derivatives (Trimethoxystilbene and Pterostilbene) to inhibit human cancer cell growth particularly analyzing their ability to interfere with tubulin dynamics at mitosis. We show that Trimethoxystilbene, differently from Resveratrol and Pterostilbene, alters microtubule polymerization dynamics in HeLa cells specifically inducing multipolar spindles and mitotic arrest coupled to a reduction of cell growth and an increase in apoptotic death by mitotic catastrophe. This work demonstrates that the structural modification of Rsv causes substantial changes in the mechanism of action of the derivatives. The presence of three extra methyl groups renders Trimethoxy very efficient in impairing cell proliferation by inducing mitotic catastrophe in cancer cells. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Growth inhibition of Erwinia amylovora and related Erwinia species by neutralized short‑chain fatty acids.

    PubMed

    Konecki, Katrin; Gernold, Marina; Wensing, Annette; Geider, Klaus

    2013-11-01

    Short-chain fatty acids (SCFAs) are used to preserve food and could be a tool for control of fire blight caused by Erwinia amylovora on apple, pear and related rosaceous plants. Neutralized acids were added to buffered growth media at 0.5–75 mM and tested at pHs ranging from 6.8 to 5.5. Particularly at low pH, SCFAs with a chain length exceeding that of acetic acid such as propionic acid were effective growth inhibitors of E. amylovora possibly due to uptake of free acid and its intracellular accumulation. We also observed high inhibition with monochloroacetic acid. An E. billingiae strain was as sensitive to the acids as E. amylovora or E. tasmaniensis. Fire blight symptoms on pear slices were reduced when the slices were pretreated with neutralized propionic acid. Propionic acid is well water soluble and could be applied in orchards as a control agent for fire blight.

  6. Components in aqueous Hibiscus rosa-sinensis flower extract inhibit in vitro melanoma cell growth.

    PubMed

    Goldberg, Karina H; Yin, Ariel C; Mupparapu, Archana; Retzbach, Edward P; Goldberg, Gary S; Yang, Catherine F

    2017-01-01

    Skin cancer is extremely common, and melanoma causes about 80% of skin cancer deaths. In fact, melanoma kills over 50 thousand people around the world each year, and these numbers are rising. Clearly, standard treatments are not effectively treating melanoma, and alternative therapies are needed to address this problem. Hibiscus tea has been noted to have medicinal properties, including anticancer effects. Extracts from Hibiscus have been shown to inhibit the growth of a variety of cancer cells. In particular, recent studies found that polyphenols extracted from Hibiscus sabdariffa by organic solvents can inhibit melanoma cell growth. However, effects of aqueous extracts from Hibiscus rosa-sinesis flowers, which are commonly used to make traditional medicinal beverages, have not been examined on melanoma cells. Here, we report that aqueous H. rosa-sinesis flower extract contains compounds that inhibit melanoma cell growth in a dose dependent manner at concentrations that did not affect the growth of nontransformed cells. In addition, these extracts contain low molecular weight growth inhibitory compounds below 3 kD in size that combine with larger compounds to more effectively inhibit melanoma cell growth. Future work should identify these compounds, and evaluate their potential to prevent and treat melanoma and other cancers.

  7. Mechanisms of growth inhibition of Phytomonas serpens by the alkaloids tomatine and tomatidine

    PubMed Central

    Medina, Jorge Mansur; Rodrigues, Juliany Cola Fernandes; Moreira, Otacilio C; Atella, Geórgia; de Souza, Wanderley; Barrabin, Hector

    2015-01-01

    Phytomonas serpens are flagellates in the family Trypanosomatidae that parasitise the tomato plant (Solanum lycopersicum L.), which results in fruits with low commercial value. The tomato glycoalkaloid tomatine and its aglycone tomatidine inhibit the growth of P. serpens in axenic cultures. Tomatine, like many other saponins, induces permeabilisation of the cell membrane and a loss of cell content, including the cytosolic enzyme pyruvate kinase. In contrast, tomatidine does not cause permeabilisation of membranes, but instead provokes morphological changes, including vacuolisation. Phytomonas treated with tomatidine show an increased accumulation of labelled neutral lipids (BODYPY-palmitic), a notable decrease in the amount of C24-alkylated sterols and an increase in zymosterol content. These results are consistent with the inhibition of 24-sterol methyltransferase (SMT), which is an important enzyme that is responsible for the methylation of sterols at the 24 position. We propose that the main target of tomatidine is the sterols biosynthetic pathway, specifically, inhibition of the 24-SMT. Altogether, the results obtained in the present paper suggest a more general effect of alkaloids in trypanosomatids, which opens potential therapeutic possibilities for the treatment of the diseases caused by these pathogens. PMID:25742263

  8. Mechanisms of growth inhibition of Phytomonas serpens by the alkaloids tomatine and tomatidine.

    PubMed

    Medina, Jorge Mansur; Rodrigues, Juliany Cola Fernandes; Moreira, Otacilio C; Atella, Geórgia; Souza, Wanderley de; Barrabin, Hector

    2015-02-01

    Phytomonas serpens are flagellates in the family Trypanosomatidae that parasitise the tomato plant (Solanum lycopersicum L.), which results in fruits with low commercial value. The tomato glycoalkaloid tomatine and its aglycone tomatidine inhibit the growth of P. serpens in axenic cultures. Tomatine, like many other saponins, induces permeabilisation of the cell membrane and a loss of cell content, including the cytosolic enzyme pyruvate kinase. In contrast, tomatidine does not cause permeabilisation of membranes, but instead provokes morphological changes, including vacuolisation. Phytomonas treated with tomatidine show an increased accumulation of labelled neutral lipids (BODYPY-palmitic), a notable decrease in the amount of C24-alkylated sterols and an increase in zymosterol content. These results are consistent with the inhibition of 24-sterol methyltransferase (SMT), which is an important enzyme that is responsible for the methylation of sterols at the 24 position. We propose that the main target of tomatidine is the sterols biosynthetic pathway, specifically, inhibition of the 24-SMT. Altogether, the results obtained in the present paper suggest a more general effect of alkaloids in trypanosomatids, which opens potential therapeutic possibilities for the treatment of the diseases caused by these pathogens.

  9. Mechanisms of growth inhibition of Phytomonas serpens by the alkaloids tomatine and tomatidine.

    PubMed

    Medina, Jorge Mansur; Rodrigues, Juliany Cola Fernandes; Moreira, Otacilio C; Atella, Geórgia; Souza, Wanderley de; Barrabin, Hector

    2015-02-13

    Phytomonas serpens are flagellates in the family Trypanosomatidae that parasitise the tomato plant (Solanum lycopersicum L.), which results in fruits with low commercial value. The tomato glycoalkaloid tomatine and its aglycone tomatidine inhibit the growth of P. serpens in axenic cultures. Tomatine, like many other saponins, induces permeabilisation of the cell membrane and a loss of cell content, including the cytosolic enzyme pyruvate kinase. In contrast, tomatidine does not cause permeabilisation of membranes, but instead provokes morphological changes, including vacuolisation. Phytomonas treated with tomatidine show an increased accumulation of labelled neutral lipids (BODYPY-palmitic), a notable decrease in the amount of C24-alkylated sterols and an increase in zymosterol content. These results are consistent with the inhibition of 24-sterol methyltransferase (SMT), which is an important enzyme that is responsible for the methylation of sterols at the 24 position. We propose that the main target of tomatidine is the sterols biosynthetic pathway, specifically, inhibition of the 24-SMT. Altogether, the results obtained in the present paper suggest a more general effect of alkaloids in trypanosomatids, which opens potential therapeutic possibilities for the treatment of the diseases caused by these pathogens.

  10. Lycobetaine acts as a selective topoisomerase IIβ poison and inhibits the growth of human tumour cells

    PubMed Central

    Barthelmes, H U; Niederberger, E; Roth, T; Schulte, K; Tang, W C; Boege, F; Fiebig, H-H; Eisenbrand, G; Marko, D

    2001-01-01

    The phenanthridine alkaloid lycobetaine is a minor constituent of Amaryllidaceae. Inhibition of cell growth was studied in the clonogenic assay on 21 human tumour xenografts (mean IC 50 = 0.8 μM). The growth of human leukaemia cell lines was also potently inhibited (mean IC 50 = 1.3 μM). Athymic nude mice, carrying s.c. implanted human gastric tumour xenograft GXF251, were treated i.p. with lycobetaine for 4 weeks, resulting in a marked tumour growth delay. Lycobetaine was found to act as a specific topoisomerase IIβ poison. In the presence of calf thymus DNA, pure recombinant human topoisomerase IIβ protein was selectively depleted from SDS-gels, whereas no depletion of topoisomerase IIα protein was observed. In A431 cells immunoband-depletion of topoisomerase IIβ was induced, suggesting stabilization of the covalent catalytic DNA-intermediate in living cells. It is reasonable to assume that this mechanism will cause or at least contribute significantly to the antitumour activity. © 2001 Cancer Research Campaign   http://www.bjcancer.com PMID:11720449

  11. Depleting Tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC.

    PubMed

    Madajewski, Brian; Boatman, Michael A; Chakrabarti, Gaurab; Boothman, David A; Bey, Erik A

    2016-01-01

    The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cytoprotective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization, and decreased three-dimensional tumor spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a protumor survival role, because its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors because NQO1 depletion significantly decreased the percentage of ALDH((high)) cancer cells within the tumor population. Loss of tumor-NQO1 expression inhibits tumor growth and suggests that novel therapeutics directed at tumor-NQO1 may have clinical benefit. ©2015 American Association for Cancer Research.

  12. Inhibition of growth and alteration of host cell interactions of Pasteurella multocida with natural byproducts.

    PubMed

    Salaheen, S; Almario, J A; Biswas, D

    2014-06-01

    Pasteurella multocida is a leading cause of fowl cholera in both free-range pasture and conventional/commercially raised poultry. Its infection is a serious threat to poultry health and overall flock viability. Organic poultry is comparatively more vulnerable to this pathogen. It is a significant cause of production loss and price increase of poultry products, specifically organic poultry products. Some plant products are well documented as sources of natural antimicrobials such as polyphenols found in different berry pomaces and citrus oil. Pomace, a byproduct (primarily of seeds and skins) of fruits used for juice and wine production, and citrus oil, the byproduct of citrus juice production, show promising antimicrobial activity against various pathogens. Here, we showed for the first time that blackberry and blueberry pomace extracts and citrus oil inhibited P. multocida growth. Minimum bactericidal concentrations were determined as 0.3 and 0.4 mg/mL gallic acid equivalent for blackberry and blueberry pomace extracts, respectively. Similarly, only 0.05% citrus oil (vol/vol) completely inhibited P. multocida growth. Under shaking conditions, the antimicrobial activity of both pomace extracts and citrus oil was more intensive. Even citrus oil vapor also significantly reduced the growth of P. multocida. In addition, cell surface hydrophobicity of P. multocida was increased by 2- to 3-fold and its adherence to chicken fibroblast (DF1) and bovine mammary gland (MacT) cells was reduced significantly in the presence of pomace extracts only. This study indicates that these natural products might be good alternatives to conventional antimicrobial agents, and hence, may be used as feed or water supplements to control fowl cholera and reduce production loss caused by P. multocida.

  13. Rapid Population Growth-Cause or Result of Global Problems?

    ERIC Educational Resources Information Center

    Schwartz, Richard H.

    Explosive population growth is a symptom of the world's unjust and inequitable social, political, and economic conditions. The current rate of growth is staggering, particularly in the cities of the underdeveloped countries. While some progress has been made in slowing population growth, several factors still contribute to its momentum. One of…

  14. Flavanols and procyanidins of cocoa and chocolate inhibit growth and polyamine biosynthesis of human colonic cancer cells.

    PubMed

    Carnésecchi, Stéphanie; Schneider, Yann; Lazarus, Sheryl A; Coehlo, David; Gossé, Francine; Raul, Francis

    2002-01-25

    The effects of cocoa powder and extracts with different amounts of flavanols and related procyanidin oligomers were investigated on the growth of Caco-2 cells. Treatment of the cells with 50 microg/ml of procyanidin-enriched (PE) extracts caused a 70% growth inhibition with a blockade of the cell cycle at the G2/M phase. PE extracts caused a significant decrease of ornithine decarboxylase and S-adenosylmethionine decarboxylase activities, two key enzymes of polyamine biosynthesis. This led to a decrease in the intracellular pool of the polyamines. These observations indicate that polyamine metabolism might be an important target in the anti-proliferative effects of cocoa polyphenols.

  15. Chemotherapy Agents and the Inhibition of Neuronal Birthing in the Brain - The Cause of Chemo Brain

    DTIC Science & Technology

    2006-11-01

    of Neuronal Birthing in the Brain – The Cause of “Chemo Brain” PRINCIPAL INVESTIGATOR: Robert A Gross, M.D., Ph.D...Chemotherapy Agents and the Inhibition of Neuronal Birthing in the Brain – The 5a. CONTRACT NUMBER Cause of “Chemo Brain” 5b. GRANT NUMBER DAMD17-03-1...agents that do not (Adriamycin and Taxol) with respect to their ability to impair the birthing of new neurons in the hippocampus of adult mice. By

  16. Compounds in a particular production lot of tryptic soy broth inhibit Staphylococcus aureus cell growth.

    PubMed

    Ishii, Masaki; Matsumoto, Yasuhiko; Sekimizu, Kazuhisa

    2015-06-01

    Staphylococcus aureus Newman strain and several methicillin-resistant S. aureus (MRSA) clinical isolates were grown on agar plates prepared with conventional lots of tryptic soy broth (TSB). Cell growth of these strains was inhibited on agar plates containing TSB of a particular product lot (lot A), whereas the cell growth of S. aureus RN4220 strain and several other MRSA clinical isolates was not inhibited. The cell growth of a strain of S. epidermidis was also inhibited on agar plates containing TSB of lot A, whereas the cell growth of Bacillus subtilis, Lactococcus lactis, Klebsiella pneumonia, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, and Escherichia coli was not inhibited. Although cell growth of the Newman strain was inhibited on agar plates containing TSB of lot A that was autoclaved in stainless steel or glass containers, cell growth inhibition was not observed when the medium was autoclaved in polypropylene containers. Compounds that inhibited the cell growth of the Newman strain were extracted from a polypropylene tube that was preincubated with liquid medium prepared from TSB of lot A. These findings suggest that polypropylene-binding compounds in TSB of lot A inhibited the cell growth of S. aureus Newman strain, some MRSA clinical isolates, and S. epidermidis.

  17. Inhibition does not always cause emotional devaluation: no evidence for retrieval-induced devaluation.

    PubMed

    Janczyk, Markus; Wühr, Peter

    2012-01-01

    Retrieval practice for some memory items from a given category can impair subsequent retrieval of unpracticed items from the same category (retrieval-induced forgetting, RIF). Inhibition of these items has been invoked as an explanation, and inhibition has also been proposed to cause stimulus devaluation. The present experiments investigated whether a similar devaluation effect can be observed in a RIF experiment for the unpracticed and presumably inhibited items. We report two experiments using the RIF paradigm, and both experiments yielded a RIF effect. At the same time, affective ratings of the very same items did not show signs of devaluation. These results run counter the idea that both RIF and devaluation effects are caused by a (similar) inhibitory mechanism, or at least they suggest differences between the mechanisms involved in external perceptual and internal memory selection.

  18. Environmental estrogens inhibit growth of rainbow trout (Oncorhynchus mykiss) by modulating the growth hormone-insulin-like growth factor system.

    PubMed

    Hanson, Andrea M; Kittilson, Jeffrey D; Martin, Lincoln E; Sheridan, Mark A

    2014-01-15

    Although environmental estrogens (EE) have been found to disrupt a wide variety of developmental and reproductive processes in vertebrates, there is a paucity of information concerning their effects on organismal growth, particularly postembryonic growth. In this study, we exposed juvenile rainbow trout (Oncorhynchus mykiss) to 17β-estradiol (E2) β-sitosterol (βS), or 4-n-nonylphenol (NP) to assess the effects of EE on overall organismal growth and on the growth hormone-insulin-like-growth factor (GH-IGF) system. EE treatment significantly reduced food conversion, body condition, and body growth. EE-inhibited growth resulted from alterations in peripheral elements of the GH-IGF system, which includes multiple GH receptors (GHRs), IGFs, and IGF receptors (IGFRs). In general, E2, βS, and NP reduced the expression of GHRs, IGFs, and IGFRs; however, the effects varied in an EE-, tissue-, element type-specific manner. For example, in liver, E2 was more efficacious than either βS, and NP in reducing GHR expression, and the effect of E2 was greater on GHR 1 than GHR2 mRNA. By contrast, in gill, all EEs affected GHR expression in a similar manner and there was no difference in the effect on GHR1 and GHR 2 mRNA. With regard to IGF expression, all EEs reduced hepatic IGF1 and IGF2 mRNA levels, whereas as in gill, only E2 and NP significantly reduced IGF1 and IGF2 expression. Lastly, E2 and NP reduced the expression of IGFR1A and IGFR1B mRNA expression similarly in gill and red and white muscle, whereas βS had no effect on expression of IGFR mRNAs. These findings indicate that EEs disrupt post-embryonic growth by reducing GH sensitivity, IGF production, and IGF sensitivity. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Inhibition of solid tumor growth by gene transfer of VEGF receptor-1 mutants.

    PubMed

    Heidenreich, Regina; Machein, Marcia; Nicolaus, Anke; Hilbig, Andreas; Wild, Carola; Clauss, Matthias; Plate, Karl H; Breier, Georg

    2004-09-01

    Vascular endothelial growth factor (VEGF) and the high-affinity VEGF receptor Flk-1/KDR (VEGFR-2) are key regulators of tumor angiogenesis. Strategies to block VEGF/VEGFR-2 signaling were successfully used to inhibit experimental tumor growth and indicated that VEGFR-2 is the main signaling VEGF receptor in proliferating tumor endothelium. Here, we investigated the role of the VEGF receptor-1 (VEGFR-1/Flt-1) in the vascularization of 2 different experimental tumors in vivo. VEGFR-1 mutants were generated that lack the intracellular tyrosine kinase domain. Retrovirus-mediated gene transfer of the VEGFR-1 mutants led to a strong reduction of tumor growth and angiogenesis in xenografted C6 glioma and in syngeneic BFS-1 fibrosarcoma. Histological analysis of the inhibited fibrosarcoma revealed reduced vascular density, decreased tumor cell proliferation as well as increased tumor cell apoptosis and the formation of necrosis. The retroviral gene transfer of the full length VEGFR-1 also caused a significant reduction of tumor growth in both models. The inhibitory effects of the VEGFR-1 mutants and the full length VEGFR-1 in BFS-1 fibrosarcoma were mediated through host tumor endothelial cells because the BFS-1 fibrosarcoma cells were not infected by the retrovirus. The formation of heterodimers between VEGFR-2 and full length or truncated VEGFR-1 was observed in vitro and might contribute to the growth inhibitory effect by modulating distinct signal transduction pathways. The results of our study underline the central role of the VEGF/VEGFR-1 signaling system in tumor angiogenesis and demonstrate that VEGFR-1 can serve as a target for anti-angiogenic gene therapy.

  20. Manganese Toxicity Inhibited Root Growth by Disrupting Auxin Biosynthesis and Transport in Arabidopsis

    PubMed Central

    Zhao, Jingjing; Wang, Wenying; Zhou, Huakun; Wang, Ruling; Zhang, Ping; Wang, Huichun; Pan, Xiangliang; Xu, Jin

    2017-01-01

    Mn toxicity inhibits both primary root (PR) growth and lateral root development. However, the mechanism underlying Mn-mediated root growth inhibition remains to be further elucidated. Here, we investigated the role of auxin in Mn-mediated inhibition of PR growth in Arabidopsis using physiological and genetic approaches. Mn toxicity inhibits PR elongation by reducing meristematic cell division potential. Mn toxicity also reduced auxin levels in root tips by reducing IAA biosynthesis and down-regulating the expression of auxin efflux carriers PIN4 and PIN7. Loss of function pin4 and pin7 mutants showed less inhibition of root growth than col-0 seedlings. These results indicated that this inhibitory effect of Mn toxicity on PR growth was mediated by affecting auxin biosynthesis and the expression of auxin efflux transporters PIN4 and PIN7. PMID:28316607

  1. Manganese Toxicity Inhibited Root Growth by Disrupting Auxin Biosynthesis and Transport in Arabidopsis.

    PubMed

    Zhao, Jingjing; Wang, Wenying; Zhou, Huakun; Wang, Ruling; Zhang, Ping; Wang, Huichun; Pan, Xiangliang; Xu, Jin

    2017-01-01

    Mn toxicity inhibits both primary root (PR) growth and lateral root development. However, the mechanism underlying Mn-mediated root growth inhibition remains to be further elucidated. Here, we investigated the role of auxin in Mn-mediated inhibition of PR growth in Arabidopsis using physiological and genetic approaches. Mn toxicity inhibits PR elongation by reducing meristematic cell division potential. Mn toxicity also reduced auxin levels in root tips by reducing IAA biosynthesis and down-regulating the expression of auxin efflux carriers PIN4 and PIN7. Loss of function pin4 and pin7 mutants showed less inhibition of root growth than col-0 seedlings. These results indicated that this inhibitory effect of Mn toxicity on PR growth was mediated by affecting auxin biosynthesis and the expression of auxin efflux transporters PIN4 and PIN7.

  2. [Inhibition of tumor growth by a peptide fusion protein binding to vascular endothelial growth factor receptor Flt-1].

    PubMed

    Lei, Hetian; Shou, Chengchao; Wu, Jian; Liu, Xiaoying; He, Luowen; Liu, Meisheng; Guo, Qi; Jiang, Beihai

    2002-10-10

    Investigating the bio-activities of peptides selected from phage display peptide library with vascular endothelial growth factor receptor Flt-1. Activities of DHFR-F56/F90 binding to human ubilial vein endothelial cells were detected by immunocytochemistry, and the activity of antiangiogenesis was determined with chick embryo chorioallantoric membrane (CAM) assay. Balb/c nude mice were used as model to detect the activity of DHFR-F56/F90 on inhibiting tumor growth, and immunohistochemistry was employed to determine the localization of the DHFR-F56/F90 in tumor. DHFR-F56/F90 can bind to HUVEC, and DHFR-F56 inhibite angiogenesis in CAM. Meanwhile DHFR-F56 can bind with tumor cells, induce tumor necrosis and inhibit tumor growth in vivo. The peptide F56 is an effective antagonist of VEGF binding to Flt-1 and has a potent utility in antiangiogenesis and inhibiting tumor growth.

  3. Catalytically Active Guanylyl Cyclase B Requires Endoplasmic Reticulum-mediated Glycosylation, and Mutations That Inhibit This Process Cause Dwarfism.

    PubMed

    Dickey, Deborah M; Edmund, Aaron B; Otto, Neil M; Chaffee, Thomas S; Robinson, Jerid W; Potter, Lincoln R

    2016-05-20

    C-type natriuretic peptide activation of guanylyl cyclase B (GC-B), also known as natriuretic peptide receptor B or NPR2, stimulates long bone growth, and missense mutations in GC-B cause dwarfism. Four such mutants (L658F, Y708C, R776W, and G959A) bound (125)I-C-type natriuretic peptide on the surface of cells but failed to synthesize cGMP in membrane GC assays. Immunofluorescence microscopy also indicated that the mutant receptors were on the cell surface. All mutant proteins were dephosphorylated and incompletely glycosylated, but dephosphorylation did not explain the inactivation because the mutations inactivated a "constitutively phosphorylated" enzyme. Tunicamycin inhibition of glycosylation in the endoplasmic reticulum or mutation of the Asn-24 glycosylation site decreased GC activity, but neither inhibition of glycosylation in the Golgi by N-acetylglucosaminyltransferase I gene inactivation nor PNGase F deglycosylation of fully processed GC-B reduced GC activity. We conclude that endoplasmic reticulum-mediated glycosylation is required for the formation of an active catalytic, but not ligand-binding domain, and that mutations that inhibit this process cause dwarfism.

  4. Catalytically Active Guanylyl Cyclase B Requires Endoplasmic Reticulum-mediated Glycosylation, and Mutations That Inhibit This Process Cause Dwarfism*

    PubMed Central

    Dickey, Deborah M.; Edmund, Aaron B.; Otto, Neil M.; Chaffee, Thomas S.; Robinson, Jerid W.; Potter, Lincoln R.

    2016-01-01

    C-type natriuretic peptide activation of guanylyl cyclase B (GC-B), also known as natriuretic peptide receptor B or NPR2, stimulates long bone growth, and missense mutations in GC-B cause dwarfism. Four such mutants (L658F, Y708C, R776W, and G959A) bound 125I-C-type natriuretic peptide on the surface of cells but failed to synthesize cGMP in membrane GC assays. Immunofluorescence microscopy also indicated that the mutant receptors were on the cell surface. All mutant proteins were dephosphorylated and incompletely glycosylated, but dephosphorylation did not explain the inactivation because the mutations inactivated a “constitutively phosphorylated” enzyme. Tunicamycin inhibition of glycosylation in the endoplasmic reticulum or mutation of the Asn-24 glycosylation site decreased GC activity, but neither inhibition of glycosylation in the Golgi by N-acetylglucosaminyltransferase I gene inactivation nor PNGase F deglycosylation of fully processed GC-B reduced GC activity. We conclude that endoplasmic reticulum-mediated glycosylation is required for the formation of an active catalytic, but not ligand-binding domain, and that mutations that inhibit this process cause dwarfism. PMID:26980729

  5. Tracing and inhibiting growth of Staphylococcus aureus in barbecue cheese production after product recall.

    PubMed

    Johler, S; Zurfluh, K; Stephan, R

    2016-05-01

    Staphylococcal food poisoning is one of the most prevalent causes of foodborne intoxication worldwide. It is caused by ingestion of enterotoxins formed by Staphylococcus aureus during growth in the food matrix. Following a recall of barbecue cheese due to the detection of staphylococcal enterotoxins in Switzerland in July 2015, we analyzed the production process of the respective dairy. Although most cheese-making processes involve acidification to inhibit the growth of pathogenic bacteria, barbecue cheese has to maintain a pH >6.0 to prevent undesired melting of the cheese. In addition, the dairy decided to retain the traditional manual production process of the barbecue cheese. In this study, therefore, we aimed to (1) trace Staph. aureus along the barbecue cheese production process, and (2) develop a sustainable strategy to inhibit growth of Staph. aureus and decrease the risk of staphylococcal food poisoning without changing the traditional production process. To this end, we traced Staph. aureus in a step-wise blinded process analysis on 4 different production days using spa (Staphylococcus protein A gene) typing, DNA microarray profiling, and pulsed-field gel electrophoresis analysis. We subsequently selected a new starter culture and used a model cheese production including a challenge test assay to assess its antagonistic effect on Staph. aureus growth, as well as its sensory and technological implications. We detected Staph. aureus in 30% (37/124) of the collected samples taken from the barbecue cheese production at the dairy. This included detection of Staph. aureus in the final product on all 4 production days, either after enrichment or using quantitative detection. We traced 2 enterotoxigenic Staph. aureus strains (t073/CC45 and t282/CC45) colonizing the nasal cavity and the forearms of the cheesemakers to the final product. In the challenge test assay, we were able to show that the new starter culture inhibited growth of Staph. aureus while meeting

  6. Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions.

    PubMed

    Hesketh, Andy; Vergnano, Marta; Wan, Chris; Oliver, Stephen G

    2017-07-25

    We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR) inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection.IMPORTANCE During infections, pathogenic bacteria can release nucleotides into the cells of their eukaryotic hosts. These nucleotides are recognized as signals that contribute to the initiation of defensive immune responses that help the infected cells

  7. Genotoxicity and growth inhibition effects of aniline on wheat.

    PubMed

    Tao, Nan; Liu, Guanyi; Bai, Lu; Tang, Lu; Guo, Changhong

    2017-02-01

    Aniline is a synthetic compound widely used in industrial and pesticide production, which can lead to environmental pollution. Its high concentration in rivers and lakes is hazardous to aquatic species. Although the mechanism of aniline toxicity has been studied extensively in animals and algae, little is known about its genotoxicity in plants. In this study, we investigated the genotoxicity effects of aniline on wheat root tip cells. The mitotic index of wheat root tip cells decreased when the aniline test concentration was higher than 10 mg L(-1). The frequency of micronucleus and chromosomal aberrations increased at aniline concentrations ranging between 5 and 100 mg L(-1), and reached 23.3‰ ± 0.3‰ and 8.9‰ ± 0.68‰, respectively, at an aniline concentration of 100 mg L(-1). These values were sevenfold higher than those in the control group. The wheat seedlings showed various growth toxicity effects under different concentrations of aniline. The shoot height, root length, fresh weight, and dry weight of wheat seedlings decreased at aniline test concentrations ranging between 25 and 200 mg L(-1). At 200 mg L(-1) aniline, the dry weight was only one-third that of the control group. Overall, the findings of this study provide evidence that aniline is a serious environmental pollutant causing deleterious genotoxic effects on wheat root tip cells and growth toxic effects on wheat seedlings. However, understanding the mechanisms that underlie aniline genotoxicity in plants needs further study.

  8. Turbulence induces metabolically costly behaviors and inhibits food capture in oyster larvae, causing net energy loss.

    PubMed

    Fuchs, Heidi L; Specht, Jaclyn A; Adams, Diane K; Christman, Adam J

    2017-10-01

    Planktotrophic invertebrate larvae require energy to develop, disperse and settle successfully, and it is unknown how their energetics are impacted by turbulence. Ciliated larvae gain metabolic energy from their phytoplankton food to offset the energetic costs of growth, development and ciliary activity for swimming and feeding. Turbulence may affect the energetic balance by inducing behaviors that alter the metabolic costs and efficiency of swimming, by raising the encounter rate with food particles and by inhibiting food capture. We used experiments and an empirical model to quantify the net rate of energy gain, swimming efficiency and food capture efficiency for eyed oyster larvae (Crassostrea virginica) in turbulence. At dissipation rates representative of coastal waters, larvae lost energy even when food concentrations were very high. Both feeding activity and turbulence-induced behaviors incurred high metabolic costs. Swimming efficiency was concave up versus dissipation rate, suggesting that ciliary activity for food handling became more costly while swimming became more efficient with turbulence intensity. Though counter-intuitive, swimming may have become more efficient in turbulence because vorticity-induced rotation caused larvae to swim more horizontally, which requires less effort than swimming vertically against the pull of gravity. Overall, however, larvae failed to offset high activity costs with food energy gains because turbulence reduced food capture efficiency more than it enhanced food encounter rates. Younger, smaller larvae may have some energetic advantages, but competent larvae would lose energy at turbulence intensities they experience frequently, suggesting that turbulence-induced starvation may account for much of oysters' high larval mortality. © 2017. Published by The Company of Biologists Ltd.

  9. Neutral pH hydrogen-enriched electrolyzed water achieves tumor-preferential clonal growth inhibition over normal cells and tumor invasion inhibition concurrently with intracellular oxidant repression.

    PubMed

    Saitoh, Yasukazu; Okayasu, Hajime; Xiao, Li; Harata, Yoshikazu; Miwa, Nobuhiko

    2008-01-01

    The properties and effects of neutral pH hydrogen-enriched electrolyzed water (NHE water) on tumor cells were examined. NHE water diminished hydroxyl radicals as demonstrated by ESR in a cell-free system. Human tongue carcinoma cells HSC-4 were inhibited for either colony formation efficiencies or colony sizes by NHE water without significant inhibition to normal human tongue epithelial-like cells DOK. Furthermore, NHE water caused growth inhibition, cell degeneration, and inhibition of invasion through the reconstituted basement membrane to human fibrosarcoma cells HT-1080. Intracellular oxidants such as hydroperoxides and hydrogen peroxides were scavenged in HSC-4 or HT-1080 cells by NHE water. In the human oral cavity, a dissolved hydrogen concentrations (DH) of NHE water was drastically declined from 1.1 to 0.5 ppm, but settled to 0.3-0.4 ppm until 180 s, upon static holding without gargling. Thus, NHE water was shown to achieve tumor-preferential growth inhibition and tumor invasion together with scavenging of intracellular oxidants, and is expected as a preventive material against tumor progression and invasion.

  10. Immunomodulatory role of bitter melon extract in inhibition of head and neck squamous cell carcinoma growth

    PubMed Central

    Bhattacharya, Sourav; Muhammad, Naoshad; Steele, Robert; Peng, Guangyong; Ray, Ratna B.

    2016-01-01

    Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer and leading cause of cancer related mortality worldwide. Despite the advancement in treatment procedures the overall survival rate of patients has not considerably enhanced in the past few decades. Therefore, new strategies to achieve a favorable response for the improvement in the prognosis of HNSCC are urgently needed. In this study, we examined the role of bitter melon extract (BME) in HNSCC tumor microenvironment. Mouse head and neck cancer (SCCVII) cells were subcutaneously injected into the flanks of syngeneic mice. We observed that oral gavage of BME significantly inhibits the tumor growth in mice as compared to control group. Further study suggested that BME inhibits cell proliferation as evident from low expression of proliferating cell nuclear antigen (PCNA) and c-Myc in the tumors of BME fed mice as compared to that of control group. We next investigated the role of BME as an immunomodulator in HNSCC model. Forkhead box protein P3+ (FoxP3+) T cells suppress tumor immunity. Our data suggested that BME treatment decreases the infiltrating regulatory T (Treg) cells by inhibiting FoxP3+ populations in the tumors and in spleens. Additionally, BME treatment reduces Th17 cell population in the tumor. However, BME treatment did not alter Th1 and Th2 cell populations. Together, our findings offer a new insight into how bitter melon extract inhibits head and neck tumor growth by modulating cell proliferation and Treg populations, with implications for how to control tumor-infiltrating lymphocytes and tumor progression. PMID:27120805

  11. Growth inhibitive effect of betulinic acid combined with tripterine on MSB-1 cells and its mechanism.

    PubMed

    An, N; Li, H Y; Zhang, X M

    2015-12-01

    Marek's disease (MD), a highly infectious lymphoproliferative disease in chickens, is caused by a cell-associated oncogenic herpesvirus, Marek's disease virus (MDV). MSB-1 is a MD-derived lymphoblastoid cell line and can induce tumors when inoculated into susceptible chickens. Betulinic acid, which is present as one of the major effective components in many traditional Chinese medicines, has recently been reported to inhibit growth of cancer cells and employed as a potential anticancer agent. Tripterine, a major active compound extracted from the Chinese herb Tripterygium wilfordii Hook F, has now also shown anti-tumor activities in various cancers. The aim of this study was to investigate the synergistic growth-inhibitive effect of betulinic acid combined with tripterine on MSB-1 cells and its mechanism. Viability of MSB-1 cells was assessed by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) method. Cell apoptotic analysis was performed by fluorescence detection. NF-κB transcription activity was detected by measuring luciferase activity. Western blotting was used to analyze the expression of p65, IκB and Meq. Our results showed that the proliferation in the combination group was significantly decreased as compared with that of monotherapy using betulinic acid or tripterine, accompanied by an induction of apoptosis, inhibition of NF-κB transcriptional activity and its targeting oncogenic gene Meq. The results suggest that the combination of betulinic acid and tripterine at lower concentration may produce a synergistic inhibitive effect on MSB-1 cells that warrants further investigation for its potential clinical applications.

  12. Grape seed extract inhibits angiogenesis via suppression of the vascular endothelial growth factor receptor signaling pathway.

    PubMed

    Wen, Wei; Lu, Jianming; Zhang, Keqiang; Chen, Shiuan

    2008-12-01

    Blockade of angiogenesis is an important approach for cancer treatment and prevention. Vascular endothelial growth factor (VEGF) is one of the most critical factors that induce angiogenesis and has thus become an attractive target for antiangiogenesis treatment. However, most current anti-VEGF agents often cause some side effects when given chronically. Identification of naturally occurring VEGF inhibitors derived from diet would be one alternative approach with an advantage of known safety. Grape seed extract (GSE), a widely used dietary supplement, is known to have antitumor activity. In this study, we have explored the activity of GSE on VEGF receptor and angiogenesis. We found that GSE could directly inhibit the kinase activity of purified VEGF receptor 2, a novel activity of GSE that has not been characterized. GSE could also inhibit the VEGF receptor/mitogen-activated protein kinase-mediated signaling pathway in endothelial cells. As a result, GSE could inhibit VEGF-induced endothelial cell proliferation and migration as well as sprout formation from aorta ring. In vivo assay further showed that GSE could inhibit tumor growth and tumor angiogenesis of MDA-MB-231 breast cancer cells in mice. Consistent with the in vitro data, GSE treatment of tumor-bearing mice led to concomitant reduction of blood vessel density and phosphorylation of mitogen-activated protein kinase. Depletion of polyphenol with polyvinylpyrrolidone abolished the antiangiogenic activity of GSE, suggesting a water-soluble fraction of polyphenol in GSE is responsible for the antiangiogenic activity. Taken together, this study indicates that GSE is a well-tolerated and inexpensive natural VEGF inhibitor and could potentially be useful in cancer prevention or treatment.

  13. The novel Aryl hydrocarbon receptor inhibitor biseugenol inhibits gastric tumor growth and peritoneal dissemination

    PubMed Central

    Lai, De-Wei; Karlsson, Anna Isabella; Wang, Keh-Bin; Chen, Yi-Ching; Shen, Chin-Chang; Wu, Sheng-Mao; Liu, Chia-Yu; Tien, Hsing-Ru; Peng, Yen-Chun; Jan, Yee-Jee; Chao, Te-Hsin; Lan, Keng-Hsin; Arbiser, Jack L.; Sheu, Meei-Ling

    2014-01-01

    Biseugenol (Eug) is known to antiproliferative of cancer cells; however, to date, the antiperitoneal dissemination effects have not been studied in any mouse cancer model. In this study, Aryl hydrocarbon receptor (AhR) expression was associated with lymph node and distant metastasis in patients with gastric cancer and was correlated with clinicolpathological pattern. We evaluated the antiperitoneal dissemination potential of knockdown AhR and Biseugenol in cancer mouse model and assessed mesenchymal characteristics. Our results demonstrate that tumor growth, peritoneal dissemination and peritoneum or organ metastasis implanted MKN45 cells were significantly decreased in shAhR and Biseugenol-treated mice and that endoplasmic reticulum (ER) stress was caused. Biseugenol-exposure tumors showed acquired epithelial features such as phosphorylation of E-cadherin, cytokeratin-18 and loss mesenchymal signature Snail, but not vimentin regulation. Snail expression, through AhR activation, is an epithelial-to-mesenchymal transition (EMT) determinant. Moreover, Biseugenol enhanced Calpain-10 (Calp-10) and AhR interaction resulted in Snail downregulation. The effect of shCalpain-10 in cancer cells was associated with inactivation of AhR/Snail promoter binding activity. Inhibition of Calpain-10 in gastric cancer cells by short hairpin RNA or pharmacological inhibitor was found to effectively reduced growth ability and vessel density in vivo. Importantly, knockdown of AhR completed abrogated peritoneal dissemination. Herein, Biseugenol targeting ER stress provokes Calpain-10 activity, sequentially induces reversal of EMT and apoptosis via AhR may involve the paralleling processes. Taken together, these data suggest that Calpain-10 activation and AhR inhibition by Biseugenol impedes both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT. PMID:25226618

  14. Pharmacological inhibition of fibroblast growth factor (FGF) receptor signaling ameliorates FGF23-mediated hypophosphatemic rickets.

    PubMed

    Wöhrle, Simon; Henninger, Christine; Bonny, Olivier; Thuery, Anne; Beluch, Noemie; Hynes, Nancy E; Guagnano, Vito; Sellers, William R; Hofmann, Francesco; Kneissel, Michaela; Graus Porta, Diana

    2013-04-01

    Fibroblast growth factor 23 (FGF23) is a circulating factor secreted by osteocytes that is essential for phosphate homeostasis. In kidney proximal tubular cells FGF23 inhibits phosphate reabsorption and leads to decreased synthesis and enhanced catabolism of 1,25-dihydroxyvitamin D3 (1,25[OH]2 D3 ). Excess levels of FGF23 cause renal phosphate wasting and suppression of circulating 1,25(OH)2 D3 levels and are associated with several hereditary hypophosphatemic disorders with skeletal abnormalities, including X-linked hypophosphatemic rickets (XLH) and autosomal recessive hypophosphatemic rickets (ARHR). Currently, therapeutic approaches to these diseases are limited to treatment with activated vitamin D analogues and phosphate supplementation, often merely resulting in partial correction of the skeletal aberrations. In this study, we evaluate the use of FGFR inhibitors for the treatment of FGF23-mediated hypophosphatemic disorders using NVP-BGJ398, a novel selective, pan-specific FGFR inhibitor currently in Phase I clinical trials for cancer therapy. In two different hypophosphatemic mouse models, Hyp and Dmp1-null mice, resembling the human diseases XLH and ARHR, we find that pharmacological inhibition of FGFRs efficiently abrogates aberrant FGF23 signaling and normalizes the hypophosphatemic and hypocalcemic conditions of these mice. Correspondingly, long-term FGFR inhibition in Hyp mice leads to enhanced bone growth, increased mineralization, and reorganization of the disturbed growth plate structure. We therefore propose NVP-BGJ398 treatment as a novel approach for the therapy of FGF23-mediated hypophosphatemic diseases. Copyright © 2013 American Society for Bone and Mineral Research.

  15. AP-2γ Induces p21 Expression, Arrests Cell Cycle, and Inhibits the Tumor Growth of Human Carcinoma Cells1

    PubMed Central

    Li, Hualei; Goswami, Prabhat C; Domann, Frederick E

    2006-01-01

    Abstract Activating enhancer-binding protein 2γ (AP-2γ) is a member of the developmentally regulated AP-2 transcription factor family that regulates the expression of many downstream genes. Whereas the effects of AP-2α overexpression on cell growth are fairly well established, the cellular effects of AP-2γ overexpression are less well studied. Our new findings show that AP-2γ significantly upregulates p21 mRNA and proteins, inhibits cell growth, and decreases clonogenic survival. Cell cycle analysis revealed that forced AP-2γ expression induced G1-phase arrest, decreased DNA synthesis, and decreased the fraction of cells in S phase. AP-2γ expression also led to cyclin D1 repression, decreased Rb phosphorylation, and decreased E2F activity in breast carcinoma cells. AP-2γ binding to the p21 promoter was observed in vivo, and the absence of growth inhibition in response to AP-2γ expression in p21 (-/-) cells demonstrated that p21 caused, at least in part, AP-2-induced cell cycle arrest. Finally, the tumor growth of human breast carcinoma cells in vivo was inhibited by the expression of AP-2γ relative to empty vector-infected cells, suggesting that AP-2γ acts as a tumor suppressor. In summary, expression of either AP-2γ or AP-2α inhibited breast carcinoma cell growth; thus, these genes may be therapeutic targets for breast cancer. PMID:16867219

  16. Bacteria Isolated from Bats Inhibit the Growth of Pseudogymnoascus destructans, the Causative Agent of White-Nose Syndrome

    PubMed Central

    Hoyt, Joseph R.; Cheng, Tina L.; Langwig, Kate E.; Hee, Mallory M.; Frick, Winifred F.; Kilpatrick, A. Marm

    2015-01-01

    Emerging infectious diseases are a key threat to wildlife. Several fungal skin pathogens have recently emerged and caused widespread mortality in several vertebrate groups, including amphibians, bats, rattlesnakes and humans. White-nose syndrome, caused by the fungal skin pathogen Pseudogymnoascus destructans, threatens several hibernating bat species with extinction and there are few effective treatment strategies. The skin microbiome is increasingly understood to play a large role in determining disease outcome. We isolated bacteria from the skin of four bat species, and co-cultured these isolates with P. destructans to identify bacteria that might inhibit or kill P. destructans. We then conducted two reciprocal challenge experiments in vitro with six bacterial isolates (all in the genus Pseudomonas) to quantify the effect of these bacteria on the growth of P. destructans. All six Pseudomonas isolates significantly inhibited growth of P. destructans compared to non-inhibitory control bacteria, and two isolates performed significantly better than others in suppressing P. destructans growth for at least 35 days. In both challenge experiments, the extent of suppression of P. destructans growth was dependent on the initial concentration of P. destructans and the initial concentration of the bacterial isolate. These results show that bacteria found naturally occurring on bats can inhibit the growth of P. destructans in vitro and should be studied further as a possible probiotic to protect bats from white-nose syndrome. In addition, the presence of these bacteria may influence disease outcomes among individuals, populations, and species. PMID:25853558

  17. Bacteria isolated from bats inhibit the growth of Pseudogymnoascus destructans, the causative agent of white-nose syndrome.

    PubMed

    Hoyt, Joseph R; Cheng, Tina L; Langwig, Kate E; Hee, Mallory M; Frick, Winifred F; Kilpatrick, A Marm

    2015-01-01

    Emerging infectious diseases are a key threat to wildlife. Several fungal skin pathogens have recently emerged and caused widespread mortality in several vertebrate groups, including amphibians, bats, rattlesnakes and humans. White-nose syndrome, caused by the fungal skin pathogen Pseudogymnoascus destructans, threatens several hibernating bat species with extinction and there are few effective treatment strategies. The skin microbiome is increasingly understood to play a large role in determining disease outcome. We isolated bacteria from the skin of four bat species, and co-cultured these isolates with P. destructans to identify bacteria that might inhibit or kill P. destructans. We then conducted two reciprocal challenge experiments in vitro with six bacterial isolates (all in the genus Pseudomonas) to quantify the effect of these bacteria on the growth of P. destructans. All six Pseudomonas isolates significantly inhibited growth of P. destructans compared to non-inhibitory control bacteria, and two isolates performed significantly better than others in suppressing P. destructans growth for at least 35 days. In both challenge experiments, the extent of suppression of P. destructans growth was dependent on the initial concentration of P. destructans and the initial concentration of the bacterial isolate. These results show that bacteria found naturally occurring on bats can inhibit the growth of P. destructans in vitro and should be studied further as a possible probiotic to protect bats from white-nose syndrome. In addition, the presence of these bacteria may influence disease outcomes among individuals, populations, and species.

  18. Local Transcriptional Control of YUCCA Regulates Auxin Promoted Root-Growth Inhibition in Response to Aluminium Stress in Arabidopsis.

    PubMed

    Liu, Guangchao; Gao, Shan; Tian, Huiyu; Wu, Wenwen; Robert, Hélène S; Ding, Zhaojun

    2016-10-01

    Auxin is necessary for the inhibition of root growth induced by aluminium (Al) stress, however the molecular mechanism controlling this is largely unknown. Here, we report that YUCCA (YUC), which encodes flavin monooxygenase-like proteins, regulates local auxin biosynthesis in the root apex transition zone (TZ) in response to Al stress. Al stress up-regulates YUC3/5/7/8/9 in the root-apex TZ, which we show results in the accumulation of auxin in the root-apex TZ and root-growth inhibition during the Al stress response. These Al-dependent changes in the regulation of YUCs in the root-apex TZ and YUC-regulated root growth inhibition are dependent on ethylene signalling. Increasing or disruption of ethylene signalling caused either enhanced or reduced up-regulation, respectively, of YUCs in root-apex TZ in response to Al stress. In addition, ethylene enhanced root growth inhibition under Al stress was strongly alleviated in yuc mutants or by co-treatment with yucasin, an inhibitor of YUC activity, suggesting a downstream role of YUCs in this process. Moreover, ethylene-insensitive 3 (EIN3) is involved into the direct regulation of YUC9 transcription in this process. Furthermore, we demonstrated that PHYTOCHROME INTERACTING FACTOR4 (PIF4) functions as a transcriptional activator for YUC5/8/9. PIF4 promotes Al-inhibited primary root growth by regulating the local expression of YUCs and auxin signal in the root-apex TZ. The Al-induced expression of PIF4 in root TZ acts downstream of ethylene signalling. Taken together, our results highlight a regulatory cascade for YUCs-regulated local auxin biosynthesis in the root-apex TZ mediating root growth inhibition in response to Al stress.

  19. Local Transcriptional Control of YUCCA Regulates Auxin Promoted Root-Growth Inhibition in Response to Aluminium Stress in Arabidopsis

    PubMed Central

    Tian, Huiyu; Wu, Wenwen; Ding, Zhaojun

    2016-01-01

    Auxin is necessary for the inhibition of root growth induced by aluminium (Al) stress, however the molecular mechanism controlling this is largely unknown. Here, we report that YUCCA (YUC), which encodes flavin monooxygenase-like proteins, regulates local auxin biosynthesis in the root apex transition zone (TZ) in response to Al stress. Al stress up-regulates YUC3/5/7/8/9 in the root-apex TZ, which we show results in the accumulation of auxin in the root-apex TZ and root-growth inhibition during the Al stress response. These Al-dependent changes in the regulation of YUCs in the root-apex TZ and YUC-regulated root growth inhibition are dependent on ethylene signalling. Increasing or disruption of ethylene signalling caused either enhanced or reduced up-regulation, respectively, of YUCs in root-apex TZ in response to Al stress. In addition, ethylene enhanced root growth inhibition under Al stress was strongly alleviated in yuc mutants or by co-treatment with yucasin, an inhibitor of YUC activity, suggesting a downstream role of YUCs in this process. Moreover, ethylene-insensitive 3 (EIN3) is involved into the direct regulation of YUC9 transcription in this process. Furthermore, we demonstrated that PHYTOCHROME INTERACTING FACTOR4 (PIF4) functions as a transcriptional activator for YUC5/8/9. PIF4 promotes Al-inhibited primary root growth by regulating the local expression of YUCs and auxin signal in the root-apex TZ. The Al–induced expression of PIF4 in root TZ acts downstream of ethylene signalling. Taken together, our results highlight a regulatory cascade for YUCs-regulated local auxin biosynthesis in the root-apex TZ mediating root growth inhibition in response to Al stress. PMID:27716807

  20. Growth inhibition and chromosomal instability of cultured marsupial (opossum) cells after treatment with DNA polymerase α inhibitor.

    PubMed

    Takemura, Masaharu; Kazama, Tomoko; Sakuma, Kurumi; Mizushina, Yoshiyuki; Oshima, Teruyoshi

    2011-01-01

    The DNA replication mechanism has been well established for eutherian mammals (placental mammals such as humans, mice, and cattle), but not, to date, for metatherian mammals (marsupials such as kangaroos, koalas, and opossums). In this study, we found that dehydroaltenusin, a selective inhibitor of mammalian (eutherian) DNA polymerase α, clearly suppressed the growth of metatherian (opossum and rat kangaroo) cultured cells. In cultured opossum (OK) cells, dehydroaltenusin also suppressed the progression of DNA replication. These results suggest that dehydroaltenusin inhibits metatherian as well as eutherian DNA replication. Dehydroaltenusin treatment of OK cells engendered fluctuations in the numbers of chromosomes in the OK cells as well as inhibition of cell growth and DNA replication. This suggests that partial inhibition of DNA replication by dehydroaltenusin causes chromosomal instability in cultured cells.

  1. Organophosphorus Flame Retardants Inhibit Specific Liver Carboxylesterases and Cause Serum Hypertriglyceridemia

    PubMed Central

    2015-01-01

    Humans are prevalently exposed to organophosphorus flame retardants (OPFRs) contained in consumer products and electronics, though their toxicological effects and mechanisms remain poorly understood. We show here that OPFRs inhibit specific liver carboxylesterases (Ces) and cause altered hepatic lipid metabolism. Ablation of the OPFR target Ces1g has been previously linked to dyslipidemia in mice. Consistent with OPFR inhibition of Ces1g, we also observe OPFR-induced serum hypertriglyceridemia in mice. Our findings suggest novel toxicities that may arise from OPFR exposure and highlight the utility of chemoproteomic and metabolomic platforms in the toxicological characterization of environmental chemicals. PMID:24597639

  2. Teroxirone inhibited growth of human non-small cell lung cancer cells by activating p53

    SciTech Connect

    Wang, Jing-Ping; Lin, Kai-Han; Liu, Chun-Yen; Yu, Ya-Chu; Wu, Pei-Tsun; Chiu, Chien-Chih; Su, Chun-Li; Chen, Kwun-Min; Fang, Kang

    2013-11-15

    In this work, we demonstrated that the growth of human non-small-cell-lung-cancer cells H460 and A549 cells can be inhibited by low concentrations of an epoxide derivative, teroxirone, in both in vitro and in vivo models. The cytotoxicity was mediated by apoptotic cell death through DNA damage. The onset of ultimate apoptosis is dependent on the status of p53. Teroxirone caused transient elevation of p53 that activates downstream p21 and procaspase-3 cleavage. The presence of caspase-3 inhibitor reverted apoptotic phenotype. Furthermore, we showed the cytotoxicity of teroxirone in H1299 cells with stable ectopic expression of p53, but not those of mutant p53. A siRNA-mediated knockdown of p53 expression attenuated drug sensitivity. The in vivo experiments demonstrated that teroxirone suppressed growth of xenograft tumors in nude mice. Being a potential therapeutic agent by restraining cell growth through apoptotic death at low concentrations, teroxirone provides a feasible perspective in reversing tumorigenic phenotype of human lung cancer cells. - Highlights: • Teroxirone repressed tumor cell growth in nude mice of human lung cancer cells. • The apoptotic cell death reverted by caspase-3 inhibitor is related to p53 status. • Teroxirone provides a good candidate for lung cancer treatment.

  3. Synergistic inhibition of human cancer cell growth by cytotoxic drugs and mixed backbone antisense oligonucleotide targeting protein kinase A

    PubMed Central

    Tortora, Giampaolo; Caputo, Rosa; Damiano, Vincenzo; Bianco, Roberto; Pepe, Stefano; Bianco, A. Raffaele; Jiang, Zhiwei; Agrawal, Sudhir; Ciardiello, Fortunato

    1997-01-01

    Protein kinase A type I plays a key role in neoplastic transformation, conveying mitogenic signals of different growth factors and oncogenes. Inhibition of protein kinase A type I by antisense oligonucleotides targeting its RIα regulatory subunit results in cancer cell growth inhibition in vitro and in vivo. A novel mixed backbone oligonucleotide HYB 190 and its mismatched control HYB 239 were tested on soft agar growth of several human cancer cell types. HYB 190 demonstrated a dose-dependent inhibition of colony formation in all cell lines whereas the HYB 239 at the same doses caused a modest or no growth inhibition. A noninhibitory dose of each mixed backbone oligonucleotide was used in OVCAR-3 ovarian and GEO colon cancer cells to study whether any cooperative effect may occur between the antisense and a series of cytotoxic drugs acting by different mechanisms. Treatment with HYB 190 resulted in an additive growth inhibitory effect with several cytotoxic drugs when measured by soft agar colony formation. A synergistic growth inhibition, which correlated with increased apoptosis, was observed when HYB 190 was added to cancer cells treated with taxanes, platinum-based compounds, and topoisomerase II selective drugs. This synergistic effect was also observed in breast cancer cells and was obtained with other related drugs such as docetaxel and carboplatin. Combination of HYB 190 and paclitaxel resulted in an accumulation of cells in late S-G2 phases of cell cycle and marked induction of apoptosis. A cooperative effect of HYB 190 and paclitaxel was also obtained in vivo in nude mice bearing human GEO colon cancer xenografts. These results are the first report of a cooperative growth inhibitory effect obtained in a variety of human cancer cell lines by antisense mixed backbone oligonucleotide targeting protein kinase A type I-mediated mitogenic signals and specific cytotoxic drugs. PMID:9356493

  4. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

    PubMed Central

    Sackett, Tara E.; Thomas, Sean C.

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)–gas chromatography–mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  5. Aluminum stress inhibits root growth and alters physiological and metabolic responses in chickpea (Cicer arietinum L.).

    PubMed

    Choudhury, Shuvasish; Sharma, Parul

    2014-12-01

    Chickpea (Cicer arietinum L.) roots were treated with aluminum (Al3+) in calcium chloride (CaCl2) solution (pH 4.7) and growth responses along with physiological and metabolic changes were investigated. Al3+ treatment for 7d resulted in a dose dependent decline of seed germination and inhibition of root growth. A significant (p ≤ 0.05) decline in fresh and dry biomass were observed after 7d of Al3+ stress.The root growth (length) was inhibited after 24 and 48 h of stress imposition. The hydrogen peroxide (H2O2) levels increased significantly (p ≤ 0.05) with respect to control in Al3+ treated roots. The hematoxylin and Evans blue assay indicated significant (p ≤ 0.05) accumulation of Al3+ in the roots and loss of plasma membrane integrity respectively. The time-course evaluation of lipid peroxidation showed increase in malondialdehyde (MDA) after 12, 24 and 48 h of stress imposition. Al3+ treatment did not alter the MDA levels after 2 or 4 h of stress, however, a minor increase was observed after 6 and 10 h of treatment. The proton (1H) nuclear magnetic resonance (NMR) spectrum of the perchloric acid extracts showed variation in the abundance of metabolites and suggested a major metabolic shift in chickpea root during Al3+ stress. The key differences that were observed include changes in energy metabolites. Accumulation of phenolic compounds suggested its possible role in Al3+ exclusion in roots during stress. The results suggested that Al3+ alters growth pattern in chickpea and induces reactive oxygen species (ROS) production that causes physiological and metabolic changes.

  6. Inhibition of human breast cancer xenograft growth by cruciferous vegetable constituent benzyl isothiocyanate.

    PubMed

    Warin, Renaud; Xiao, Dong; Arlotti, Julie A; Bommareddy, Ajay; Singh, Shivendra V

    2010-05-01

    Benzyl isothiocyanate (BITC), a constituent of cruciferous vegetables such as garden cress, inhibits growth of human breast cancer cell lines in culture. The present study was undertaken to determine in vivo efficacy of BITC against MDA-MB-231 human breast cancer xenografts. The BITC administration retarded growth of MDA-MB-231 cells subcutaneously implanted in female nude mice without causing weight loss or any other side effects. The BITC-mediated suppression of MDA-MB-231 xenograft growth correlated with reduced cell proliferation as revealed by immunohistochemical analysis for Ki-67 expression. Analysis of the vasculature in the tumors from BITC-treated mice indicated smaller vessel area compared with control tumors based on immunohistochemistry for angiogenesis marker CD31. The BITC-mediated inhibition of angiogenesis in vivo correlated with downregulation of vascular endothelial growth factor (VEGF) receptor 2 protein levels in the tumor. Consistent with these results, BITC treatment suppressed VEGF secretion and VEGF receptor 2 protein levels in cultured MDA-MB-231 cells. Moreover, the BITC-treated MDA-MB-231 cells exhibited reduced capacity for migration compared with vehicle-treated control cells. In contrast to cellular data, BITC administration failed to elicit apoptotic response as judged by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. In conclusion, the present study demonstrates in vivo anti-cancer efficacy of BITC against MDA-MB-231 xenografts in association with reduced cell proliferation and suppression of neovascularization. These preclinical observations merit clinical investigation to determine efficacy of BITC against human breast cancers. (c) 2010 Wiley-Liss, Inc.

  7. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds.

    PubMed

    Gale, Nigel V; Sackett, Tara E; Thomas, Sean C

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  8. UV photolysis for relieved inhibition of sulfadiazine (SD) to biomass growth.

    PubMed

    Pan, Shihui; Yan, Ning; Zhang, Yongming; Rittmann, Bruce E

    2015-05-01

    UV photolysis was used to relieve inhibition of biomass growth by sulfadiazine (SD), a broad-spectrum anti-microbial. To investigate the effects of SD on biomass growth, three substrates-glucose alone (G), glucose plus sulfadiazine (G+SD), and glucose plus photolyzed SD (G+PSD)-were used to culture the bacteria acclimated to glucose. The biomass was strongly inhibited when SD was added into the glucose solution, but inhibition was relieved to a significant degree when the SD was treated with UV irradiation as a pretreatment. The biomass growth kinetics were described well by the Monod model when glucose was used as a substrate alone, but the kinetics followed a hybrid Aiba model for non-competitive inhibition when SD was added to the solution. When photolyzed SD was added to glucose solution to replace original SD, the growth still followed Aiba inhibition, but inhibition was significantly relieved: the maximum specific growth rate (μ max) increased by 17 %, and the Aiba inhibition concentration increased by 60 %. Aniline, a major product of UV photolysis, supported the growth of the glucose-biodegrading bacteria. Thus, UV photolysis of SD significantly relieved inhibition by lowering the SD concentration and by generating a biodegradable product.

  9. Simultaneous inhibition of key growth pathways in melanoma cells and tumor regression by a designed bidentate constrained helical peptide.

    PubMed

    Dhar, Amlanjyoti; Mallick, Shampa; Ghosh, Piya; Maiti, Atanu; Ahmed, Israr; Bhattacharya, Seemana; Mandal, Tapashi; Manna, Asit; Roy, Koushik; Singh, Sandeep; Nayak, Dipak Kumar; Wilder, Paul T; Markowitz, Joseph; Weber, David; Ghosh, Mrinal K; Chattopadhyay, Samit; Guha, Rajdeep; Konar, Aditya; Bandyopadhyay, Santu; Roy, Siddhartha

    2014-07-01

    Protein-protein interactions are part of a large number of signaling networks and potential targets for drug development. However, discovering molecules that can specifically inhibit such interactions is a major challenge. S100B, a calcium-regulated protein, plays a crucial role in the proliferation of melanoma cells through protein-protein interactions. In this article, we report the design and development of a bidentate conformationally constrained peptide against dimeric S100B based on a natural tight-binding peptide, TRTK-12. The helical conformation of the peptide was constrained by the substitution of α-amino isobutyric acid--an amino acid having high helical propensity--in positions which do not interact with S100B. A branched bidentate version of the peptide was bound to S100B tightly with a dissociation constant of 8 nM. When conjugated to a cell-penetrating peptide, it caused growth inhibition and rapid apoptosis in melanoma cells. The molecule exerts antiproliferative action through simultaneous inhibition of key growth pathways, including reactivation of wild-type p53 and inhibition of Akt and STAT3 phosphorylation. The apoptosis induced by the bidentate constrained helix is caused by direct migration of p53 to mitochondria. At moderate intravenous dose, the peptide completely inhibits melanoma growth in a mouse model without any significant observable toxicity. The specificity was shown by lack of ability of a double mutant peptide to cause tumor regression at the same dose level. The methodology described here for direct protein-protein interaction inhibition may be effective for rapid development of inhibitors against relatively weak protein-protein interactions for de novo drug development.

  10. Cell growth inhibition and DNA incorporation of mitomycin C in cell culture.

    PubMed

    Takahashi, N; Murayama, T; Oda, M; Miyakoshi, M

    1998-01-01

    The present study was performed to clarify the effects of a 4-min exposure of mitomycin C (MMC) on cell growth, the cell cycle and MMC dose incorporated into DNA, using Chang's cultured human conjunctival cells. A low dose of MMC ranging from 0.00025 to 0.004% showed dose-dependent cytotoxicity when cell growth was active. Fifty percent cell viability was found when cells were treated with 0.001% MMC. A flow cytometer showed that 0.001% MMC inhibited the DNA synthetic phase. After 0.04% MMC was exposed to 3 x 10(6) cells and immediately rinsed, DNA was isolated to measure the dose of MMC detected from DNA. The total amount of DNA was 7 micrograms from which 3 micrograms of MMC was detected by high performance liquid chromatography. The above results revealed that the lowest concentration of MMC which caused 50% cell viability and cell cycle inhibition was 0.001% and that MMC was rapidly incorporated into DNA.

  11. Alphaxalone inhibits growth, migration and invasion of rat C6 malignant glioma cells.

    PubMed

    Sun, Huawei; Zheng, Xiaoke; Zhou, Yuehan; Zhu, Wenbo; Ou, Yanqiu; Shu, Minfeng; Gao, Xiuren; Leng, Tiandong; Qiu, Pengxin; Yan, Guangmei

    2013-10-01

    Malignant gliomas are the most devastating and aggressive brain tumors affecting the central nervous system. The insidious growth and infiltration are the most prominent characteristics of malignant gliomas, which render the current therapies for malignant gliomas including surgery, radiation and chemotherapy unsuccessful. Inhibition of infiltration as well as proliferation in combination with surgery might be more effective in the treatment of malignant gliomas. In the current study, we demonstrate the alphaxalone (3-hydroxypregnane-11,20-dione) could effectively inhibit the proliferation of C6 glioma cells in a concentration dependent manner. Moreover, this compound could also suppress the migration and invasion of C6 glioma cells at a concentration without causing significant cytotoxicity. Except the in vitro anti-glioma activity, alphaxalone effectively delayed the growth of rat C6 malignant glioma xenografts in vivo. Together, these findings suggest alphaxalone might be a promising candidate for the treatment of malignant gliomas and may also provide helpful clues for anti-glioma drugs development in future.

  12. Local Anesthetics Inhibit the Growth of Human Hepatocellular Carcinoma Cells.

    PubMed

    Le Gac, Grégoire; Angenard, Gaëlle; Clément, Bruno; Laviolle, Bruno; Coulouarn, Cédric; Beloeil, Hélène

    2017-08-29

    Hepatocellular carcinoma (HCC) is an aggressive cancer with limited therapeutic options. Retrospective studies have shown that the administration of local anesthetics (LAs) during cancer surgery could reduce cancer recurrence. Besides, experimental studies reported that LAs could inhibit the growth of cancer cells. Thus, the purpose of this study was to investigate the effects of LAs on human HCC cells. The effects of 2 LAs (lidocaine and ropivacaine) (10 to 10 M) were studied after an incubation of 48 hours on 2 HCC cell lines, namely HuH7 and HepaRG. Cell viability, cell cycle analysis, and apoptosis and senescence tests were performed together with unsupervised genome-wide expression profiling and quantitative real-time polymerase chain reaction for relevant genes. We showed that LAs decreased viability and proliferation of HuH7 cells (from 92% [P < .001] at 5 × 10 M to 40% [P = .02] at 10 M with ropivacaine and from 87% [P < .001] to 37% [P = .02] with lidocaine) and HepaRG progenitor cells (from 58% at 5 × 10 M [P < .001] to 29% at 10 M [P = .04] with lidocaine and 59% [P < .001] with ropivacaine 5 × 10 M) in concentration-dependent manner. LAs have no effect on well-differentiated HepaRG. Ropivacaine decreased the mRNA level of key cell cycle regulators, namely cyclin A2, cyclin B1, cyclin B2, and cyclin-dependent kinase 1, and the expression of the nuclear marker of cell proliferation MKI67. Lidocaine had no specific effect on cell cycle but increased by 10× the mRNA level of adenomatous polyposis coli (P < .01), which acts as an antagonist of the Wnt/β-catenin pathway. Both LAs increased apoptosis in Huh7 and HepaRG progenitor cells (P < .01). The data demonstrate that LAs induced profound modifications in gene expression profiles of tumor cells, including modulations in the expression of cell cycle-related genes that result in a cytostatic effect and induction of apoptosis.

  13. Inhibition of corneal neovascularization by vascular endothelia growth inhibitor gene

    PubMed Central

    Wang, Hong; Wang, Bing; Zhang, Zhen-Hai

    2010-01-01

    AIM To evaluate the effect of Effectene™ lipofectine mediated plasmids encoding human pcDNA4-vascular endothelia growth inhibitor (pcDNA4-VEGI) gene on corneal neovascularization (CNV). METHODS Forty New Zealand albino rabbits were sutured by 5-0 silk on the superior cornea to establish the animal model and divided into 4 random group, ten per each group: group A: transfected by pcDNA4-VEGI gene mediated by Effectene™ lipofectine transfection, group B: by Plasmid pcDNA4, group C: by Effectene™, and group D: by normal saline. Length and area of CNV were measured under slit lamp every day after transfection, immunohistochemistry was used to detected the expression of VEGI protein in cornea at 3, 7, 14 and 21 days. RESULTS Average occurrence of CNV in the pcDNA4-VEGI gene transfected group (group A) was 6.3 days, in plasmid pcDNA4 control group (group B) was 3.1 days, in Effectene™ lipofectine control group (group C) was 3.2 days, in normal saline control group (group D) was 3.2 days. Differences between groups A and B, C, D were statistically significant (P<0.01), while differences in groups B, C and D were meaningless (P>0.05). Lenth and average area of CNV in each period in group A was meaningful different from that in groups B, C, and D (P<0.01), while differences in group B, C and D were meaningless (P>0.05). Immunohistochemistry result: VEGI positive cells could be seen in epithelium, stroma, endothelium and the cliff of CNV in group A at 3 days after transfection. VEGI cells changed with the decrease of CNV. None positive cells were in the control groups (groups B, C and D) all the time. CONCLUSION Effectene™ lipofectine transfection technique can be effectively used in transfecting pcDNA4-VEGI gene into rabbit cornea and the lenth and areas of CNV can be inhibited by VEGI gene. PMID:22553552

  14. Inhibition of Fusarium graminearum growth in flour gel cultures by hexane-soluble compounds from oat (Avena sativa L.) flour.

    PubMed

    Doehlert, Douglas C; Rayas-Duarte, Patricia; McMullen, Michael S

    2011-12-01

    Fusarium head blight, incited by the fungus Fusarium graminearum, primarily affects wheat (Triticum aestivum) and barley (Hordeum vulgarum), while oat (Avena sativa) appears to be more resistant. Although this has generally been attributed to the open panicle of oats, we hypothesized that a chemical component of oats might contribute to this resistance. To test this hypothesis, we created culture media made of wheat, barley, and oat flour gels (6 g of flour in 20 ml of water, gelled by autoclaving) and inoculated these with plugs of F. graminearum from actively growing cultures. Fusarium growth was measured from the diameter of the fungal plaque. Plaque diameter was significantly smaller on oat flour cultures than on wheat or barley cultures after 40 to 80 h of growth. Ergosterol concentration was also significantly lower in oat cultures than in wheat cultures after growth. A hexane extract from oats added to wheat flour also inhibited Fusarium growth, and Fusarium grew better on hexane-defatted oat flour. The growth of Fusarium on oat flour was significantly and negatively affected by the oil concentration in the oat, in a linear relationship. A hexane-soluble chemical in oat flour appears to inhibit Fusarium growth and might contribute to oat's resistance to Fusarium head blight. Oxygenated fatty acids, including hydroxy, dihydroxy, and epoxy fatty acids, were identified in the hexane extracts and are likely candidates for causing the inhibition.

  15. Combination oral antiangiogenic therapy with thalidomide and sulindac inhibits tumour growth in rabbits

    PubMed Central

    Verheul, H M W; Panigrahy, D; Yuan, J; D'Amato, R J

    1999-01-01

    Neovascularization facilitates tumour growth and metastasis formation. In our laboratory, we attempt to identify clinically available oral efficacious drugs for antiangiogenic activity. Here, we report which non-steroidal anti-inflammatory drugs (NSAIDs) can inhibit corneal neovascularization, induced by basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF). This antiangiogenic activity may contribute to the known effects of NSAIDs on gastric ulcers, polyps and tumours. We found that sulindac was one of the most potent antiangiogenic NSAIDs, inhibiting bFGF-induced neovascularization by 50% and VEGF-induced neovascularization by 55%. Previously, we reported that thalidomide inhibited growth factor-induced corneal neovascularization. When we combined sulindac with thalidomide, we found a significantly increased inhibition of bFGF- or VEGF-induced corneal neovascularization (by 63% or 74% respectively) compared with either agent alone (P< 0.01). Because of this strong antiangiogenic effect, we tested the oral combination of thalidomide and sulindac for its ability to inhibit the growth of V2 carcinoma in rabbits. Oral treatment of thalidomide or sulindac alone inhibited tumour growth by 55% and 35% respectively. When given together, the growth of the V2 carcinoma was inhibited by 75%. Our results indicated that oral antiangiogenic combination therapy with thalidomide and sulindac may be a useful non-toxic treatment for cancer. © 1999 Cancer Research Campaign PMID:10408702

  16. Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro

    PubMed Central

    Jeong, Clara H.; Gao, Liying; Dettro, Tyler; Wagner, Elizabeth D.; Ricke, William A.; Plewa, Michael J.; Flaws, Jodi A.

    2016-01-01

    Water disinfection greatly reduced the incidence of waterborne diseases, but the reaction between disinfectants and natural organic matter in water leads to the formation of drinking water disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25–1.00 mM of CAA; 2–15 µM of BAA or IAA) for 48 and 96 h. Follicle growth was measured every 24 h and the media were analyzed for estradiol levels at 96 h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro. PMID:27151372

  17. Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro.

    PubMed

    Jeong, Clara H; Gao, Liying; Dettro, Tyler; Wagner, Elizabeth D; Ricke, William A; Plewa, Michael J; Flaws, Jodi A

    2016-07-01

    Water disinfection greatly reduced the incidence of waterborne diseases, but the reaction between disinfectants and natural organic matter in water leads to the formation of drinking water disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25-1.00mM of CAA; 2-15μM of BAA or IAA) for 48 and 96h. Follicle growth was measured every 24h and the media were analyzed for estradiol levels at 96h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro.

  18. IPP5 inhibits neurite growth in primary sensory neurons by maintaining TGF-β/Smad signaling.

    PubMed

    Han, Qing-Jian; Gao, Nan-Nan; Guo-QiangMa; Zhang, Zhen-Ning; Yu, Wen-Hui; Pan, Jing; Wang, Qiong; Zhang, Xu; Bao, Lan

    2013-01-15

    During nerve regeneration, neurite growth is regulated by both intrinsic molecules and extracellular factors. Here, we found that inhibitor 5 of protein phosphatase 1 (IPP5), a newly identified inhibitory subunit of protein phosphatase 1 (PP1), inhibited neurite growth in primary sensory neurons as an intrinsic regulator. IPP5 was highly expressed in the primary sensory neurons of rat dorsal root ganglion (DRG) and was downregulated after sciatic nerve axotomy. Knocking down IPP5 with specific shRNA increased the length of the longest neurite, the total neurite length and the number of neurite ends in cultured rat DRG neurons. Mutation of the PP1-docking motif K(8)IQF(11) or the PP1-inhibiting motif at Thr(34) eliminated the IPP5-induced inhibition of neurite growth. Furthermore, biochemical experiments showed that IPP5 interacted with type I transforming growth factor-β receptor (TβRI) and PP1 and enhanced transforming growth factor-β (TGF-β)/Smad signaling in a PP1-dependent manner. Overexpressing IPP5 in DRG neurons aggravated TGF-β-induced inhibition of neurite growth, which was abolished by blocking PP1 or IPP5 binding to PP1. Blockage of TGF-β signaling with the TβRI inhibitor SB431542 or Smad2 shRNA attenuated the IPP5-induced inhibition of neurite growth. Thus, these data indicate that selectively expressed IPP5 inhibits neurite growth by maintaining TGF-β signaling in primary sensory neurons.

  19. Galactose inhibits auxin-induced growth of Avena coleoptiles by two mechanisms

    NASA Technical Reports Server (NTRS)

    Cheung, S. P.; Cleland, R. E.

    1991-01-01

    Galactose inhibits auxin-induced growth of Avena coleoptiles by at least two mechanisms. First, it inhibits auxin-induced H(+)-excretion needed for the initiation of rapid elongation. Galactose cannot be doing so by directly interfering with the ATPase since fusicoccin-induced H(+)-excretion is not affected. Secondly, galactose inhibits long-term auxin-induced growth, even in an acidic (pH 4.5) solution. This may be due to an inhibition of cell wall synthesis. However, galactose does not reduce the capacity of walls to be loosened by H+, given exogenously or excreted in response to fusicoccin.

  20. Galactose inhibits auxin-induced growth of Avena coleoptiles by two mechanisms

    NASA Technical Reports Server (NTRS)

    Cheung, S. P.; Cleland, R. E.

    1991-01-01

    Galactose inhibits auxin-induced growth of Avena coleoptiles by at least two mechanisms. First, it inhibits auxin-induced H(+)-excretion needed for the initiation of rapid elongation. Galactose cannot be doing so by directly interfering with the ATPase since fusicoccin-induced H(+)-excretion is not affected. Secondly, galactose inhibits long-term auxin-induced growth, even in an acidic (pH 4.5) solution. This may be due to an inhibition of cell wall synthesis. However, galactose does not reduce the capacity of walls to be loosened by H+, given exogenously or excreted in response to fusicoccin.

  1. Inhibition of histone deacetylase in utero causes sociability deficits in postnatal mice.

    PubMed

    Moldrich, Randal X; Leanage, Gayeshika; She, David; Dolan-Evans, Elliot; Nelson, Michael; Reza, Nargis; Reutens, David C

    2013-11-15

    Exposure to sodium valproate (VPA) in utero increases the risk of language impairment and a diagnosis of autism spectrum disorder (ASD). Mice exposed to VPA while in utero have also shown postnatal social deficits. Inhibition of histone deacetylase (HDAC) is one of VPA's many biological effects. The main objective of this study was to test the hypothesis that HDAC inhibition causes these behavioral outcomes following prenatal VPA exposure in mice. We exposed embryonic mice to VPA, the HDAC inhibitor trichostatin A (TSA), or vehicle controls. TSA (1mg/kg) inhibited HDAC in embryonic tissue at a level comparable to 600 mg/kg VPA, resulting in significant increases in histone H3 and H4 acetylation, and histone H3 lysine 4 tri-methylation. Postnatally, decreases in ultrasonic vocalization, olfactory motivation and sociability were observed in TSA and VPA-exposed pups. Treated mice exhibited elevated digging and grooming suggestive of mild restrictive and repetitive behaviors. Olfactory social preference, social novelty and habituation were normal. Together, these data indicate that embryonic HDAC inhibition alone can cause abnormal social behaviors in mice. This result serves as a molecular understanding of infant outcomes following mild VPA exposure in utero.

  2. Paradoxical Inhibition of Glycolysis by Pioglitazone Opposes the Mitochondriopathy Caused by AIF Deficiency.

    PubMed

    Bénit, Paule; Pelhaître, Alice; Saunier, Elise; Bortoli, Sylvie; Coulibaly, Assetou; Rak, Malgorzata; Schiff, Manuel; Kroemer, Guido; Zeviani, Massimo; Rustin, Pierre

    2017-03-01

    Mice with the hypomorphic AIF-Harlequin mutation exhibit a highly heterogeneous mitochondriopathy that mostly affects respiratory chain complex I, causing a cerebral pathology that resembles that found in patients with AIF loss-of-function mutations. Here we describe that the antidiabetic drug pioglitazone (PIO) can improve the phenotype of a mouse Harlequin (Hq) subgroup, presumably due to an inhibition of glycolysis that causes an increase in blood glucose levels. This glycolysis-inhibitory PIO effect was observed in cultured astrocytes from Hq mice, as well as in human skin fibroblasts from patients with AIF mutation. Glycolysis inhibition by PIO resulted from direct competitive inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Moreover, GAPDH protein levels were reduced in the cerebellum and in the muscle from Hq mice that exhibited an improved phenotype upon PIO treatment. Altogether, our results suggest that excessive glycolysis participates to the pathogenesis of mitochondriopathies and that pharmacological inhibition of glycolysis may have beneficial effects in this condition. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Resveratrol compounds inhibit human holocarboxylase synthetase and cause a lean phenotype in Drosophila melanogaster

    PubMed Central

    Cordonier, Elizabeth L.; Adjam, Riem; Camara Teixeira, Daniel; Onur, Simone; Zbasnik, Richard; Read, Paul E.; Döring, Frank; Schlegel, Vicki L.; Zempleni, Janos

    2015-01-01

    Holocarboxylase synthetase (HLCS) is the sole protein-biotin ligase in the human proteome. HLCS has key regulatory functions in intermediary metabolism, including fatty acid metabolism, and in gene repression through epigenetic mechanisms. The objective of this study was to identify foodborne inhibitors of HLCS that alter HLCS-dependent pathways in metabolism and gene regulation. When libraries of extracts from natural products and chemically pure compounds were screened for HLCS inhibitor activity, resveratrol compounds in grape materials caused an HLCS inhibition of >98% in vitro. The potency of these compounds was piceatannol > resveratrol > piceid. Grape-borne compounds other than resveratrol metabolites also contributed toward HLCS inhibition, e.g., p-coumaric acid and cyanidin chloride. HLCS inhibitors had meaningful effects on body fat mass. When Drosophila melanogaster brummer mutants, which are genetically predisposed to storing excess amounts of lipids, were fed diets enriched with grape leaf extracts and piceid, body fat mass decreased by more than 30% in males and females. However, Drosophila responded to inhibitor treatment with an increase in the expression of HLCS, which elicited an increase in the abundance of biotinylated carboxylases in vivo. We conclude that mechanisms other than inhibition of HLCS cause body fat loss in flies. We propose that the primary candidate is the inhibition of the insulin receptor/Akt signaling pathway. PMID:26303405

  4. Polo-like kinase 1 inhibition diminishes acquired resistance to epidermal growth factor receptor inhibition in non-small cell lung cancer with T790M mutations

    PubMed Central

    Wang, Liguang; Nilsson, Monique; Goonatilake, Ruchitha; Tong, Pan; Li, Lerong; Giri, Uma; Villalobos, Pamela; Mino, Barbara; Rodriguez-Canales, Jaime; Wistuba, Ignacio; Wang, Jing; Heymach, John V.; Johnson, Faye M.

    2016-01-01

    Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective against non-small cell lung cancer (NSCLC) with activating EGFR mutations, but resistance is inevitable. Mechanisms of acquired resistance include T790M mutations and epithelial–mesenchymal transition (EMT). One potential strategy for overcoming this resistance is the inhibition of polo-like kinase 1 (PLK1) based on our previous studies showing that mesenchymal NSCLC cell lines are more sensitive to PLK1 inhibition than epithelial cell lines. To determine the extent to which PLK1 inhibition overcomes EGFR TKI resistance we measured the effects of the PLK1 inhibitor volasertib alone and in combination with the EGFR inhibitor erlotinib in vitro and in vivo in EGFR mutant NSCLC cell lines with acquired resistance to erlotinib. Two erlotinib-resistant cell lines that underwent EMT had higher sensitivity to volasertib, which caused G2/M arrest and apoptosis, than their parental cells. In all NSCLC cell lines with T790M mutations, volasertib markedly reduced erlotinib resistance. All erlotinib-resistant NSCLC cell lines with T790M mutations had higher sensitivity to erlotinib plus volasertib than to erlotinib alone, and the combination treatment caused G2/M arrest and apoptosis. Compared with either agent alone, the combination treatment also caused significantly more DNA damage and greater reductions in tumor size. Our results suggest that PLK1 inhibition is clinically effective against NSCLC that becomes resistant to EGFR inhibition through EMT or the acquisition of a T790M mutation. These results uncover new functions of PLK1 inhibition in the treatment of NSCLC with acquired resistance to EGFR TKIs. PMID:27384992

  5. Prevention of VEGF-induced growth and tube formation in human retinal endothelial cell by aldose reductase inhibition

    PubMed Central

    Yadav, Umesh CS; Srivastava, SK; Ramana, KV

    2012-01-01

    Objective Since diabetes-induced vascular endothelial growth factor (VEGF) is implicated in retinal angiogenesis, we aimed to examine the role of aldose reductase (AR) in VEGF–induced human retinal endothelial cell (HREC) growth and tube formation. Materials and Methods HREC were stimulated with VEGF and cell-growth was determined by MTT assay. AR inhibitor, fidarestat, to block the enzyme activity and AR siRNA to ablate AR gene expression in HREC were used to investigate the role of AR in neovascularization using cell-migration and tube formation assays. Various signaling intermediates and angiogenesis markers were assessed by Western blot analysis. Immuno-histochemical analysis of diabetic rat eyes was performed to examine VEGF expression in the retinal layer. Results Stimulation of primary HREC with VEGF caused increased cell growth and migration, and AR inhibition with fidarestat or ablation with siRNA significantly prevented it. VEGF-induced tube formation in HREC was also significantly prevented by fidarestat. Treatment of HREC with VEGF also increased the expression of VCAM, AR, and phosphorylation and activation of Akt and p38-MAP kinase, which were prevented by fidarestat. VEGF-induced expression of VEGFRII in HREC was also prevented by AR inhibition or ablation. Conclusions Our results indicate that inhibition of AR in HREC prevents tube formation by inhibiting the VEGF-induced activation of the Akt and p38-MAPK pathway and suggest a mediatory role of AR in ocular neovascularization generally implicated in retinopathy and AMD. PMID:22658411

  6. Plant Lectin Can Target Receptors Containing Sialic Acid, Exemplified by Podoplanin, to Inhibit Transformed Cell Growth and Migration

    PubMed Central

    Shen, Yongquan; Acharya, Nimish K.; Han, Min; McNulty, Dean E.; Hasegawa, Hitoki; Hyodo, Toshinori; Senga, Takeshi; Geng, Jian-Guo; Kosciuk, Mary; Shin, Seung S.; Goydos, James S.; Temiakov, Dmitry; Nagele, Robert G.; Goldberg, Gary S.

    2012-01-01

    Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth. PMID:22844530

  7. Plant lectin can target receptors containing sialic acid, exemplified by podoplanin, to inhibit transformed cell growth and migration.

    PubMed

    Ochoa-Alvarez, Jhon Alberto; Krishnan, Harini; Shen, Yongquan; Acharya, Nimish K; Han, Min; McNulty, Dean E; Hasegawa, Hitoki; Hyodo, Toshinori; Senga, Takeshi; Geng, Jian-Guo; Kosciuk, Mary; Shin, Seung S; Goydos, James S; Temiakov, Dmitry; Nagele, Robert G; Goldberg, Gary S

    2012-01-01

    Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth.

  8. Increased Expression of FoxM1 Transcription Factor in Respiratory Epithelium Inhibits Lung Sacculation and Causes Clara Cell Hyperplasia

    PubMed Central

    Wang, I-Ching; Zhang, Yufang; Snyder, Jonathan; Sutherland, Mardi J.; Burhans, Michael S.; Shannon, John M.; Park, Hyun Jung; Whitsett, Jeffrey A.; Kalinichenko, Vladimir V.

    2010-01-01

    Foxm1 is a member of the Forkhead Box (Fox) family of transcription factors. Foxm1 (previously called Foxm1b, HFH-11B, Trident, Win, or MPP2) is expressed in multiple cell types and plays important roles in cellular proliferation, differentiation and tumorigenesis. Genetic deletion of Foxm1 from mouse respiratory epithelium during initial stages of lung development inhibits lung maturation and causes respiratory failure after birth. However, the role of Foxm1 during postnatal lung morphogenesis remains unknown. In the present study, Foxm1 expression was detected in epithelial cells of conducting and peripheral airways and changing dynamically with lung maturation. To discern the biological role of Foxm1 in the prenatal and postnatal lung, a novel transgenic mouse line that expresses a constitutively active form of FoxM1 (FoxM1 N-terminal deletion mutant or FoxM1-ΔN) under the control of lung epithelial-specific SPC promoter was produced. Expression of the FoxM1-ΔN transgene during embryogenesis caused epithelial hyperplasia, inhibited lung sacculation and expression of the type II epithelial marker, pro-SPC. Expression of FoxM1-ΔN mutant during the postnatal period did not influence alveologenesis but caused focal airway hyperplasia and increased proliferation of Clara cells. Likewise, expression of FoxM1-ΔN mutant in conducting airways with Scgb1a1 promoter was sufficient to induce Clara cell hyperplasia. Furthermore, FoxM1-ΔN cooperated with activated K-Ras to induce lung tumor growth in vivo. Increased activity of Foxm1 altered lung sacculation, induced proliferation in the respiratory epithelium and accelerated lung tumor growth, indicating that precise regulation of Foxm1 is critical for normal lung morphogenesis and development of lung cancer. PMID:20816795

  9. Stability and inhibition of anaerobic processes caused by insufficiency or excess of ammonia nitrogen.

    PubMed

    Procházka, Jindřich; Dolejš, Petr; Máca, Josef; Dohányos, Michal

    2012-01-01

    Ammonia increases buffer capacity of methanogenic medium in mesophilic anaerobic reactor thus increasing the stability of anaerobic digestion process. Optimal ammonia concentration ensures sufficient buffer capacity while not inhibiting the process. It was found out in this paper that this optimum depends on the quality of anaerobic sludge under investigation. The optimal concentrations for methanogens were 2.1, 2.6 and 3.1 g/L of ammonia nitrogen in dependence on inoculum origin. High ammonia nitrogen concentration (4.0 g/L) inhibited methane production, while low ammonia nitrogen concentration (0.5 g/L) caused low methane yield, loss of biomass (as VSS) and loss of the aceticlastic methanogenic activity. It was found out that negative effect of low ammonia nitrogen concentration on biomass is caused not only by low buffer capacity but also by insufficiency of nitrogen as nutrient. It was also found out that anaerobic sludge with higher ammonia nitrogen concentration (4.2 g/L) tolerates even concentration of volatile fatty acids (160 mmol/L) which causes inhibition of the process with low ammonia nitrogen concentration (0.2 g/L).

  10. Bismuth(III) deferiprone effectively inhibits growth of Desulfovibrio desulfuricans ATCC 27774.

    PubMed

    Barton, Larry L; Lyle, Daniel A; Ritz, Nathaniel L; Granat, Alex S; Khurshid, Ali N; Kherbik, Nada; Hider, Robert; Lin, Henry C

    2016-04-01

    Sulfate-reducing bacteria have been implicated in inflammatory bowel diseases and ulcerative colitis in humans and there is an interest in inhibiting the growth of these sulfide-producing bacteria. This research explores the use of several chelators of bismuth to determine the most effective chelator to inhibit the growth of sulfate-reducing bacteria. For our studies, Desulfovibrio desulfuricans ATCC 27774 was grown with nitrate as the electron acceptor and chelated bismuth compounds were added to test for inhibition of growth. Varying levels of inhibition were attributed to bismuth chelated with subsalicylate or citrate but the most effective inhibition of growth by D. desulfuricans was with bismuth chelated by deferiprone, 3-hydroxy-1,2-dimethyl-4(1H)-pyridone. Growth of D. desulfuricans was inhibited by 10 μM bismuth as deferiprone:bismuth with either nitrate or sulfate respiration. Our studies indicate deferiprone:bismuth has bacteriostatic activity on D. desulfuricans because the inhibition can be reversed following exposure to 1 mM bismuth for 1 h at 32 °C. We suggest that deferiprone is an appropriate chelator for bismuth to control growth of sulfate-reducing bacteria because deferiprone is relatively nontoxic to animals, including humans, and has been used for many years to bind Fe(III) in the treatment of β-thalassemia.

  11. MITF suppression by CH5552074 inhibits cell growth in melanoma cells.

    PubMed

    Aida, Satoshi; Sonobe, Yukiko; Yuhki, Munehiro; Sakata, Kiyoaki; Fujii, Toshihiko; Sakamoto, Hiroshi; Mizuno, Takakazu

    2017-06-01

    Although treatment of melanoma with BRAF inhibitors and immune checkpoint inhibitors achieves a high response rate, a subset of melanoma patients with intrinsic and acquired resistance are insensitive to these therapeutics, so to improve melanoma therapy other target molecules need to be found. Here, we screened our chemical library to identify an anti-melanoma agent and examined its action mechanisms to show cell growth inhibition activity. We screened a chemical library against multiple skin cancer cell lines and conducted ingenuity pathway analysis (IPA) to investigate the mechanisms of CH5552074 activity. Suppression of microphthalmia-associated transcription factor (MITF) expression levels was determined in melanoma cells treated with CH5552074. Cell growth inhibition activity of CH5552074 was evaluated in MITF-dependent melanoma cell lines. We identified an anti-melanoma compound, CH5552074, which showed remarkable cell growth inhibition activity in melanoma cell lines. The IPA results suggested that CH5552074-sensitive cell lines had activated MITF. In further in vitro studies in the melanoma cell lines, a knockdown of MITF with siRNA resulted in cell growth inhibition, which showed that CH5552074 inhibited cell growth by reducing the expression level of MITF protein. These results suggest that CH5552074 can inhibit cell growth in melanoma cells by reducing the protein level of MITF. MITF inhibition by CH5552074 would be an attractive option for melanoma treatment.

  12. Metformin inhibits growth of lung adenocarcinoma cells by inducing apoptosis via the mitochondria-mediated pathway

    PubMed Central

    WANG, JUNLING; GAO, QIULING; WANG, DECUI; WANG, ZHIQIANG; HU, CHUN

    2015-01-01

    Metformin is commonly used to treat type II diabetes, although it may also reduce the risk of cancer and improve the associated prognosis. However, its mode of action in cancer remains unclear. The present study evaluated the effects of metformin on lung adenocarcinoma A549 cells and identified molecular mechanisms of metformin activity. The A549 cells were treated with metformin at different concentrations and cell viability was assayed by using an MTT assay. The cell cycle and the apoptosis rate were assayed by flow cytometry. Nude mice were transplanted with A549 cells and the tumor growth inhibition rate was detected. Once the A549 cells had been treated with 20 mM metformin for 48 h, the cell cycle was arrested in the G0/Gl phase and the apoptosis rate was 20.57±3.16%. The expression of the B-cell lymphoma (Bcl)-2 and Bcl-extra large proteins was downregulated following metformin treatment, while Bax protein expression was significantly increased. Tumor size in the high-dose metformin and cisplatin plus metformin groups was significantly smaller, and the inhibition rates were 41.3 and 72.9%, respectively, compared with the control group. These results indicated that metformin displays anticancer activity against lung adenocarcinoma by causing G1 arrest of the cell cycle and subsequent cell apoptosis through the mitochondria-dependent pathway in A549 cells. Furthermore, it was found that metformin dramatically inhibited lung adenocarcinoma tumor growth in vivo. These data suggest that metformin may become a potential cytotoxic drug in the prevention and treatment of lung adenocarcinoma. PMID:26622674

  13. A chrysin derivative suppresses skin cancer growth by inhibiting cyclin-dependent kinases.

    PubMed

    Liu, Haidan; Liu, Kangdong; Huang, Zunnan; Park, Chan-Mi; Thimmegowda, N R; Jang, Jae-Hyuk; Ryoo, In-Ja; He, Long; Kim, Sun-Ok; Oi, Naomi; Lee, Ki Won; Soung, Nak-Kyun; Bode, Ann M; Yang, Yifeng; Zhou, Xinmin; Erikson, Raymond L; Ahn, Jong-Seog; Hwang, Joonsung; Kim, Kyoon Eon; Dong, Zigang; Kim, Bo-Yeon

    2013-09-06

    Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P(+) cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P(+) cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency.

  14. A Chrysin Derivative Suppresses Skin Cancer Growth by Inhibiting Cyclin-dependent Kinases*

    PubMed Central

    Liu, Haidan; Liu, Kangdong; Huang, Zunnan; Park, Chan-Mi; Thimmegowda, N. R.; Jang, Jae-Hyuk; Ryoo, In-Ja; He, Long; Kim, Sun-Ok; Oi, Naomi; Lee, Ki Won; Soung, Nak-Kyun; Bode, Ann M.; Yang, Yifeng; Zhou, Xinmin; Erikson, Raymond L.; Ahn, Jong-Seog; Hwang, Joonsung; Kim, Kyoon Eon; Dong, Zigang; Kim, Bo-Yeon

    2013-01-01

    Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P+ cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P+ cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency. PMID:23888052

  15. Synergistic action of auxin and ethylene on root elongation inhibition is caused by a reduction of epidermal cell length.

    PubMed

    Alarcón, M Victoria; Lloret, Pedro G; Salguero, Julio

    2014-01-01

    Auxin and ethylene have been largely reported to reduce root elongation in maize primary root. However the effects of auxin are greater than those caused by ethylene. Although auxin stimulates ethylene biosynthesis through the specific increase of ACC synthase, the auxin inhibitory effect on root elongation is not mediated by the auxin-induced increase of ethylene production. Recently it has been demonstrated that root inhibition by the application of the synthetic auxin NAA (1-naphtalenacetic acid) is increased if combined with the ethylene precursor ACC (1-aminocyclopropane-1-carboxilic acid) when both compounds are applied at very low concentrations.   Root elongation is basically the result of two processes: a) cell divisions in the meristem where meristematic cells continuously generate new cells and b) subsequently polarized growth by elongation along the root axis as cells leave the meristem and enter the root elongation zone. Our results indicate that exogenous auxin reduced both root elongation and epidermal cell length. In a different way, ethylene at very low concentrations only inhibited root elongation without affecting significantly epidermal cell length. However, these concentrations of ethylene increased the inhibitory effect of auxin on root elongation and cell length. Consequently the results support the hypothesis that ethylene acts synergistically with auxin in the regulation of root elongation and that inhibition by both hormones is due, at least partially, to the reduction of cell length in the epidermal layer.

  16. Synergistic action of auxin and ethylene on root elongation inhibition is caused by a reduction of epidermal cell length

    PubMed Central

    Alarcón, M Victoria; Lloret, Pedro G; Salguero, Julio

    2014-01-01

    Auxin and ethylene have been largely reported to reduce root elongation in maize primary root. However the effects of auxin are greater than those caused by ethylene. Although auxin stimulates ethylene biosynthesis through the specific increase of ACC synthase, the auxin inhibitory effect on root elongation is not mediated by the auxin-induced increase of ethylene production. Recently it has been demonstrated that root inhibition by the application of the synthetic auxin NAA (1-naphtalenacetic acid) is increased if combined with the ethylene precursor ACC (1-aminocyclopropane-1-carboxilic acid) when both compounds are applied at very low concentrations. Root elongation is basically the result of two processes: a) cell divisions in the meristem where meristematic cells continuously generate new cells and b) subsequently polarized growth by elongation along the root axis as cells leave the meristem and enter the root elongation zone. Our results indicate that exogenous auxin reduced both root elongation and epidermal cell length. In a different way, ethylene at very low concentrations only inhibited root elongation without affecting significantly epidermal cell length. However, these concentrations of ethylene increased the inhibitory effect of auxin on root elongation and cell length. Consequently the results support the hypothesis that ethylene acts synergistically with auxin in the regulation of root elongation and that inhibition by both hormones is due, at least partially, to the reduction of cell length in the epidermal layer. PMID:24598313

  17. Inhibition of the in-vitro growth of Mycobacterium tuberculosis by a phytosiderophore.

    PubMed

    Rajiv, J; Dam, T; Kumar, S; Bose, M; Aggarwal, K K; Babu, C R

    2001-10-01

    Non-compliance by patients and poor clinical management due to the use of incorrect regimens are the main reasons for the development of drug resistance by mycobacterial strains. New strategies for the control of multi-drug-resistant mycobacterial strains have become a necessity for proper management of tuberculosis, which, according to the WHO report (1997), is estimated to remain among the top 10 mortality-causing diseases of the twenty-first century. One of the strategies is the use of iron-sequestering agents like siderophores as active therapeutic agents in the treatment of tuberculosis. This report describes for the first time the inhibition of the growth of Mycobacterium tuberculosis H37Ra in vitro by a phytosiderophore isolated from the root washings of Tephrosia purpurea. This finding may help in the establishment of a new drug regimen which will be more effective in the treatment of tuberculosis.

  18. Drought causes reduced growth of trembling aspen in western Canada.

    PubMed

    Chen, Lei; Huang, Jian-Guo; Alam, Syed Ashraful; Zhai, Lihong; Dawson, Andria; Stadt, Kenneth J; Comeau, Philip G

    2017-07-01

    Adequate and advance knowledge of the response of forest ecosystems to temperature-induced drought is critical for a comprehensive understanding of the impacts of global climate change on forest ecosystem structure and function. Recent massive decline in aspen-dominated forests and an increased aspen mortality in boreal forests have been associated with global warming, but it is still uncertain whether the decline and mortality are driven by drought. We used a series of ring-width chronologies from 40 trembling aspen (Populus tremuloides Michx.) sites along a latitudinal gradient (from 52° to 58°N) in western Canada, in an attempt to clarify the impacts of drought on aspen growth by using Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). Results indicated that prolonged and large-scale droughts had a strong negative impact on trembling aspen growth. Furthermore, the spatiotemporal variability of drought indices is useful for explaining the spatial heterogeneity in the radial growth of trembling aspen. Due to ongoing global warming and rising temperatures, it is likely that severer droughts with a higher frequency will occur in western Canada. As trembling aspen is sensitive to drought, we suggest that drought indices could be applied to monitor the potential effects of increased drought stress on aspen trees growth, achieve classification of eco-regions and develop effective mitigation strategies to maintain western Canadian boreal forests. © 2017 John Wiley & Sons Ltd.

  19. Inhibition of established subcutaneous murine tumour growth with topical Melaleuca alternifolia (tea tree) oil.

    PubMed

    Greay, Sara J; Ireland, Demelza J; Kissick, Haydn T; Heenan, Peter J; Carson, Christine F; Riley, Thomas V; Beilharz, Manfred W

    2010-11-01

    Systemic toxicity coupled with long treatment regimes of approved topical chemotherapeutic agents such as imiquimod and 5-fluorouracil (5-FU) are limiting. There is now more focus on the potential use of topical terpene agents as skin cancer treatments. Here, we show for the first time that topical Melaleuca alternifolia (tea tree) oil (TTO), abundant in terpenes, has in vivo antitumour activity. Topical TTO formulations applied to immunocompetent tumour-bearing mice were assessed for antitumour efficacy by monitoring tumour growth and by histological analysis following treatment. Four, daily, topical treatments of 10% TTO/DMSO regressed subcutaneous AE17 mesotheliomas in mice for a period of 10 days and significantly retarded the growth of subcutaneous B16-F10 melanomas. The antitumour effect of topical 10% TTO/DMSO was accompanied by skin irritation similar to other topical chemotherapeutic agents, but unlike other approved topical agents, quickly and completely resolved. Furthermore, we show that topical 10% TTO/DMSO caused an influx of neutrophils and other immune effector cells in the treated area, with no evidence of systemic toxicity. TTO combined with an effective carrier significantly inhibited the growth of aggressive, subcutaneous, chemo-resistant tumours in immunocompetent mice. Taken together, these findings highlight the potential of topical TTO as an alternative topical antitumour treatment.

  20. Inhibition of metastasis, angiogenesis, and tumor growth by Chinese herbal cocktail Tien-Hsien Liquid

    PubMed Central

    2010-01-01

    , our results show that THL inhibited the growth of human MDA-MB-231 breast cancer xenografts in NOD-SCID mice. This suppression of tumor growth was associated with decreased microvessel formation and increased apoptosis caused by THL. Conclusion Our data demonstrate that THL had broad-spectra anti-cancer activities and merits further evaluation for its use in cancer therapy. PMID:20429953

  1. Fei-Liu-Ping ointment inhibits lung cancer growth and invasion by suppressing tumor inflammatory microenvironment

    PubMed Central

    2014-01-01

    Background Lung cancer is one of the leading causes of cancer-related mortality worldwide. Conventional chemotherapy and radiotherapy are the primary therapeutic methods for lung cancer with the use of combination therapies gaining popularity. The frequency and duration of treatment, as well as, managing lung cancer by targeting multiple aspects of cancer biology is often limited by toxicity to the patient. There are many naturally occurring anticancer agents that have a high degree of efficacy and low toxicity, offering a viable and safe approach for the treatment of lung cancer. The herbs traditionally used in Chinese medicine for anticancer treatment offer great potential to enhance the efficacy of conventional therapy. In this study, we evaluated the synergistic effects of Fei-Liu-Ping (FLP) ointment in treating lung cancer; a known anticancer Chinese herbal based formula. Methods In this study, A549 human lung carcinoma cell line and Lewis lung carcinoma xenograft mouse model were used. In addition, we utilized an in vitro co-culture system to simulate the tumor microenvironment in order to evaluate the molecular mechanisms of FLP treatment. Results FLP treatment significantly inhibited tumor growth in the Lewis lung xenograft by 40 percent, compared to that of cyclophosphamide (CTX) of 62.02 percent. Moreover, combining FLP and CTX inhibited tumor growth by 83.23 percent. Upon evaluation, we found that FLP treatment reduced the concentration of serum pro-inflammatory cytokines IL-6, TNF-α, and IL-1β. In addition, we also found an improvement in E-cadherin expression and inhibition of N-cadherin and MMP9. We found similar findings in vitro when we co-cultured A549 cells with macrophages. FLP treatment inhibited A549 cell growth, invasion and metastasis, in part, through the regulation of NF-κB and altering the expression of E-cadherin, N-cadherin, MMP2 and MMP9. Conclusions FLP exerts anti-inflammatory properties in the tumor microenvironment, which may

  2. Ice Growth Inhibition in Antifreeze Polypeptide Solution by Short-Time Solution Preheating

    PubMed Central

    Nishi, Naoto; Miyamoto, Takuya; Waku, Tomonori; Tanaka, Naoki; Hagiwara, Yoshimichi

    2016-01-01

    The objective of this study is to enhance the inhibition of ice growth in the aqueous solution of a polypeptide, which is inspired by winter flounder antifreeze protein. We carried out measurements on unidirectional freezing of the polypeptide solution. The thickness of the solution was 0.02 mm, and the concentration of polypeptide was varied from 0 to 2 mg/mL. We captured successive microscopic images of ice/solution interfaces, and measured the interface velocity from the locations of tips of the pectinate interface in the images. We also simultaneously measured the temperature by using a small thermocouple. The ice/solution interface temperature was defined by the temperature at the tips. It was found that the interface temperature was decreased with an increasing concentration of polypeptide. To try varying the activity of the polypeptide, we preheated the polypeptide solution and cooled it before carrying out the measurements. Preheating for 1–5 hours was found to cause a further decrease in the interface temperature. Furthermore, wider regions of solution and ice with inclined interfaces in the pectinate interface structure were observed, compared with the case where the solution was not preheated. Thus, the ice growth inhibition was enhanced by this preheating. To investigate the reason for this enhancement, we measured the conformation and aggregates of polypeptide in the solution. We also measured the local concentration of polypeptide. It was found that the polypeptide aggregates became larger as a result of preheating, although the polypeptide conformation was unchanged. These large aggregates caused both adsorption to the interface and the wide regions of supercooled solution in the pectinate interface structure. PMID:27152720

  3. Ice Growth Inhibition in Antifreeze Polypeptide Solution by Short-Time Solution Preheating.

    PubMed

    Nishi, Naoto; Miyamoto, Takuya; Waku, Tomonori; Tanaka, Naoki; Hagiwara, Yoshimichi

    2016-01-01

    The objective of this study is to enhance the inhibition of ice growth in the aqueous solution of a polypeptide, which is inspired by winter flounder antifreeze protein. We carried out measurements on unidirectional freezing of the polypeptide solution. The thickness of the solution was 0.02 mm, and the concentration of polypeptide was varied from 0 to 2 mg/mL. We captured successive microscopic images of ice/solution interfaces, and measured the interface velocity from the locations of tips of the pectinate interface in the images. We also simultaneously measured the temperature by using a small thermocouple. The ice/solution interface temperature was defined by the temperature at the tips. It was found that the interface temperature was decreased with an increasing concentration of polypeptide. To try varying the activity of the polypeptide, we preheated the polypeptide solution and cooled it before carrying out the measurements. Preheating for 1-5 hours was found to cause a further decrease in the interface temperature. Furthermore, wider regions of solution and ice with inclined interfaces in the pectinate interface structure were observed, compared with the case where the solution was not preheated. Thus, the ice growth inhibition was enhanced by this preheating. To investigate the reason for this enhancement, we measured the conformation and aggregates of polypeptide in the solution. We also measured the local concentration of polypeptide. It was found that the polypeptide aggregates became larger as a result of preheating, although the polypeptide conformation was unchanged. These large aggregates caused both adsorption to the interface and the wide regions of supercooled solution in the pectinate interface structure.

  4. Role of duty cycle on Pseudomonas aeruginosa growth inhibition mechanisms by positive electric pulses.

    PubMed

    Ali, Fadel M; Elgebaly, Reem H; Elneklawi, Mona S; Othman, Amal S

    2016-08-12

    P. aeruginosa considered as a notoriously difficult organism to be controlled by antibiotics or disinfectants. The potential use of alternative means as an aid to avoid the wide use of antibiotics against bacteria pathogen has been recently arisen remarkably. Effect of extremely low frequency positive electric pulse with different duty cycles on Pseudomonas aeruginosa (ATCC: 27853) growth by constructed and implemented exposure device was investigated in this study. The exposure device was applied to give extremely low frequency in the range of 0.1 up to 20 Hz with the capability to control the duty cycle of each pulse with variation from 10% up to 100%. Growth curves of Pseudomonas aeruginosa were investigated before and after exposure to different frequencies (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 Hz) through measuring the optical density and cell count. Exposures to selected frequencies in the whole ranges of duty cycles were done. These studies were followed by DNA fragmentation, transmission electron microscope (TEM), antibiotic susceptibility tests, and dielectric measurements. Findings revealed inhibition effect by 48.56% and 47.4% together with change in the DNA structural properties for samples exposed to 0.5 Hz and 0.7 Hz respectively. Moreover the data indicated important role of duty cycle on the inhibition mechanism. It is concluded that there are two different mechanisms of interaction between positive electric pulse and microorganism occurred; 0.5 Hz caused rupture in cell wall while 0.7 Hz caused denaturation of the inner consistent of the cell.

  5. Inhibition of ROMK blocks macula densa tubuloglomerular feedback yet causes renal vasoconstriction in anesthetized rats.

    PubMed

    Araujo, Magali; Welch, William J; Zhou, Xiaoyan; Sullivan, Kathleen; Walsh, Shawn; Pasternak, Alexander; Wilcox, Christopher S

    2017-06-01

    The Na(+)-K(+)-2Cl(-) cotransporter (NKCC2) on the loop of Henle is the site of action of furosemide. Because outer medullary potassium channel (ROMK) inhibitors prevent reabsorption by NKCC2, we tested the hypothesis that ROMK inhibition with a novel selective ROMK inhibitor (compound C) blocks tubuloglomerular feedback (TGF) and reduces vascular resistance. Loop perfusion of either ROMK inhibitor or furosemide caused dose-dependent blunting of TGF, but the response to furosemide was 10-fold more sensitive (IC50 = 10(-6) M for furosemide and IC50 = 10(-5) M for compound C). During systemic infusion, both diuretics inhibited TGF, but ROMK inhibitor was 10-fold more sensitive (compound C: 63% inhibition; furosemide: 32% inhibition). Despite blockade of TGF, 1 h of constant systemic infusion of both diuretics reduced the glomerular filtration rate (GFR) and renal blood flow (RBF) by 40-60% and increased renal vascular resistance (RVR) by 100-200%. Neither diuretic altered blood pressure or hematocrit. Proximal tubule hydrostatic pressures (PPT) increased transiently with both diuretics (compound C: 56% increase; furosemide: 70% increase) but returned to baseline. ROMK inhibitor caused more natriuresis (3,400 vs. 1,600% increase) and calciuresis (1,200 vs. 800% increase) but less kaliuresis (33 vs. 167% increase) than furosemide. In conclusion, blockade of ROMK or Na(+)-K(+)-2Cl(-) transport inhibits TGF yet increases renal vascular resistance. The renal vasoconstriction was independent of volume depletion, blood pressure, TGF, or PPT. Copyright © 2017 the American Physiological Society.

  6. The Rac Inhibitor EHop-016 Inhibits Mammary Tumor Growth and Metastasis in a Nude Mouse Model

    PubMed Central

    Castillo-Pichardo, Linette; Humphries-Bickley, Tessa; De La Parra, Columba; Forestier-Roman, Ingrid; Martinez-Ferrer, Magaly; Hernandez, Eliud; Vlaar, Cornelis; Ferrer-Acosta, Yancy; Washington, Anthony V.; Cubano, Luis A.; Rodriguez-Orengo, Jose; Dharmawardhane, Suranganie

    2014-01-01

    Metastatic disease still lacks effective treatments, and remains the primary cause of cancer mortality. Therefore, there is a critical need to develop better strategies to inhibit metastatic cancer. The Rho family GTPase Rac is an ideal target for anti-metastatic cancer therapy, because Rac is a key molecular switch that is activated by a myriad of cell surface receptors to promote cancer cell migration/invasion and survival. Previously, we reported the design and development of EHop-016, a small molecule compound, which inhibits Rac activity of metastatic cancer cells with an IC50 of 1 μM. EHop-016 also inhibits the activity of the Rac downstream effector p21-activated kinase (PAK), lamellipodia extension, and cell migration in metastatic cancer cells. Herein, we tested the efficacy of EHop-016 in a nude mouse model of experimental metastasis, where EHop-016 administration at 25 mg/kg body weight (BW) significantly reduced mammary fat pad tumor growth, metastasis, and angiogenesis. As quantified by UPLC MS/MS, EHop-016 was detectable in the plasma of nude mice at 17 to 23 ng/ml levels at 12 h following intraperitoneal (i.p.) administration of 10 to 25 mg/kg BW EHop-016. The EHop-016 mediated inhibition of angiogenesis In Vivo was confirmed by immunohistochemistry of excised tumors and by In Vitro tube formation assays of endothelial cells. Moreover, EHop-016 affected cell viability by down-regulating Akt and Jun kinase activities and c-Myc and Cyclin D expression, as well as increasing caspase 3/7 activities in metastatic cancer cells. In conclusion, EHop-016 has potential as an anticancer compound to block cancer progression via multiple Rac-directed mechanisms. PMID:25389450

  7. Protein Expression Signatures for Inhibition of Epidermal Growth Factor Receptor-mediated Signaling*

    PubMed Central

    Myers, Matthew V.; Manning, H. Charles; Coffey, Robert J.; Liebler, Daniel C.

    2012-01-01

    Analysis of cellular signaling networks typically involves targeted measurements of phosphorylated protein intermediates. However, phosphoproteomic analyses usually require affinity enrichment of phosphopeptides and can be complicated by artifactual changes in phosphorylation caused by uncontrolled preanalytical variables, particularly in the analysis of tissue specimens. We asked whether changes in protein expression, which are more stable and easily analyzed, could reflect network stimulation and inhibition. We employed this approach to analyze stimulation and inhibition of the epidermal growth factor receptor (EGFR) by EGF and selective EGFR inhibitors. Shotgun analysis of proteomes from proliferating A431 cells, EGF-stimulated cells, and cells co-treated with the EGFR inhibitors cetuximab or gefitinib identified groups of differentially expressed proteins. Comparisons of these protein groups identified 13 proteins whose EGF-induced expression changes were reversed by both EGFR inhibitors. Targeted multiple reaction monitoring analysis verified differential expression of 12 of these proteins, which comprise a candidate EGFR inhibition signature. We then tested these 12 proteins by multiple reaction monitoring analysis in three other models: 1) a comparison of DiFi (EGFR inhibitor-sensitive) and HCT116 (EGFR-insensitive) cell lines, 2) in formalin-fixed, paraffin-embedded mouse xenograft DiFi and HCT116 tumors, and 3) in tissue biopsies from a patient with the gastric hyperproliferative disorder Ménétrier's disease who was treated with cetuximab. Of the proteins in the candidate signature, a core group, including c-Jun, Jagged-1, and Claudin 4, were decreased by EGFR inhibitors in all three models. Although the goal of these studies was not to validate a clinically useful EGFR inhibition signature, the results confirm the hypothesis that clinically used EGFR inhibitors generate characteristic protein expression changes. This work further outlines a prototypical

  8. The Rac Inhibitor EHop-016 Inhibits Mammary Tumor Growth and Metastasis in a Nude Mouse Model.

    PubMed

    Castillo-Pichardo, Linette; Humphries-Bickley, Tessa; De La Parra, Columba; Forestier-Roman, Ingrid; Martinez-Ferrer, Magaly; Hernandez, Eliud; Vlaar, Cornelis; Ferrer-Acosta, Yancy; Washington, Anthony V; Cubano, Luis A; Rodriguez-Orengo, Jose; Dharmawardhane, Suranganie

    2014-10-01

    Metastatic disease still lacks effective treatments, and remains the primary cause of cancer mortality. Therefore, there is a critical need to develop better strategies to inhibit metastatic cancer. The Rho family GTPase Rac is an ideal target for anti-metastatic cancer therapy, because Rac is a key molecular switch that is activated by a myriad of cell surface receptors to promote cancer cell migration/invasion and survival. Previously, we reported the design and development of EHop-016, a small molecule compound, which inhibits Rac activity of metastatic cancer cells with an IC50 of 1 μM. EHop-016 also inhibits the activity of the Rac downstream effector p21-activated kinase (PAK), lamellipodia extension, and cell migration in metastatic cancer cells. Herein, we tested the efficacy of EHop-016 in a nude mouse model of experimental metastasis, where EHop-016 administration at 25 mg/kg body weight (BW) significantly reduced mammary fat pad tumor growth, metastasis, and angiogenesis. As quantified by UPLC MS/MS, EHop-016 was detectable in the plasma of nude mice at 17 to 23 ng/ml levels at 12 h following intraperitoneal (i.p.) administration of 10 to 25 mg/kg BW EHop-016. The EHop-016 mediated inhibition of angiogenesis In Vivo was confirmed by immunohistochemistry of excised tumors and by In Vitro tube formation assays of endothelial cells. Moreover, EHop-016 affected cell viability by down-regulating Akt and Jun kinase activities and c-Myc and Cyclin D expression, as well as increasing caspase 3/7 activities in metastatic cancer cells. In conclusion, EHop-016 has potential as an anticancer compound to block cancer progression via multiple Rac-directed mechanisms.

  9. Suramin inhibits growth and transforming growth factor-beta 1 (TGF-beta 1) binding in osteosarcoma cell lines.

    PubMed

    Kloen, P; Jennings, C L; Gebhardt, M C; Springfield, D S; Mankin, H J

    1994-01-01

    Autocrine production of growth factors has been shown to be involved in the multistep process of tumorigenesis. The ability of suramin, a polyanionic anti-parasitic drug, to block growth factor-induced cell proliferation makes it a potential antineoplastic drug. We studied the effects of suramin on seven osteosarcoma cell lines. Using clinically achievable concentrations of suramin (50-400 micrograms/ml), we found a time- and dose-dependent inhibition of [3H]thymidine incorporation. We also showed that suramin is able, dose-dependently, to prevent binding of transforming growth factor (TGF)-beta 1 to its receptors. DNA synthesis inhibition by suramin was attenuated by TGF-beta 1 in some cell lines. Two cell lines that were inhibited by TGF-beta 1 were affected similarly by suramin as cell lines that were stimulated by TGF-beta 1. In conclusion, in five out of seven osteosarcoma cell lines, we showed a correlation between inhibition of growth factor-stimulated mitogenesis and binding of TGF-beta 1 to its receptor. Similar effects in TGF-beta 1-inhibited osteosarcoma cell lines suggest involvement of other mechanisms and/or growth factors. However, suramin proves to be a potent inhibitor of osteosarcoma cell proliferation in vitro.

  10. Aflatoxin exposure in utero causes growth faltering in Gambian infants.

    PubMed

    Turner, Paul C; Collinson, Andrew C; Cheung, Yin Bun; Gong, Yunyun; Hall, Andrew J; Prentice, Andrew M; Wild, Christopher P

    2007-10-01

    Growth faltering in West African children has previously been associated with dietary exposure to aflatoxins, particularly upon weaning. However, in animal studies in utero exposure to low levels of aflatoxin also results in growth faltering. This study investigated the effect of in utero aflatoxin exposure on infant growth in the first year of life in The Gambia. Height and weight were measured for 138 infants at birth and at regular monthly intervals for one year. Aflatoxin-albumin (AF-alb) adduct level was measured in maternal blood during pregnancy, in cord blood and in infants at age 16 weeks. The geometric mean AF-alb levels were 40.4 pg/mg (range 4.8-260.8 pg/mg), 10.1 pg/mg (range 5.0-189.6 pg/mg) and 8.7 pg/mg (range 5.0-30.2 pg/mg) in maternal, cord and infant blood, respectively. AF-alb in maternal blood was a strong predictor of both weight (P = 0.012) and height (P = 0.044) gain, with lower gain in those with higher exposure. A reduction of maternal AF-alb from 110 pg/mg to 10 pg/mg would lead to a 0.8 kg increase in weight and 2 cm increase in height within the first year of life. This study shows a strong effect of maternal aflatoxin exposure during pregnancy on growth in the first year of life and thus extends earlier observations of an association between aflatoxin exposure during infancy and growth faltering. The findings imply value in targeting intervention strategies at early life exposures.

  11. Histone deacetylase 6 promotes growth of glioblastoma through inhibition of SMAD2 signaling.

    PubMed

    Li, Shun; Liu, Xiao; Chen, Xiangrong; Zhang, Liu; Wang, Xiangyu

    2015-12-01

    Histone deacetylases (HDACs) play a role in the tumorigenesis of glioblastoma multiforme (GBM), whereas the underlying mechanism has not been elucidated. Here, we reported significantly higher HDAC6 levels in GBM from the patients. GBM cell growth was significantly inhibited by ACY-1215, a specific HDAC6 inhibitor. Further analyses show that HDAC6 may promote growth of GBM cells through inhibition of SMAD2 phosphorylation to downregulate p21. Thus, our data demonstrate a previously unrecognized regulation pathway in that HDAC6 increases GBM growth through attenuating transforming growth factor β (TGFβ) receptor signaling.

  12. Cathepsin Inhibition Prevents Autophagic Protein Turnover and Downregulates Insulin Growth Factor-1 Receptor-Mediated Signaling in Neuroblastoma.

    PubMed

    Soori, Mehrnoosh; Lu, Guizhen; Mason, Robert W

    2016-02-01

    Inhibition of the major lysosomal proteases, cathepsins B, D, and L, impairs growth of several cell types but leads to apoptosis in neuroblastoma. The goal of this study was to examine the mechanisms by which enzyme inhibition could cause cell death. Cathepsin inhibition caused cellular accumulation of fragments of the insulin growth factor 1 (IGF-1) receptor. The fragments were located in dense organelles that were characterized as autophagosomes. This novel discovery provides the first clear link between lysosomal function, autophagy, and IGF-1- mediated cell proliferation. A more in-depth analysis of the IGF1 signaling pathway revealed that the mitogen-activated protein kinase (MAPK) cell-proliferation pathway was impaired in inhibitor treated cells, whereas the Akt cell survival pathway remained functional. Shc, an adapter protein that transmits IGF-1 signaling through the MAPK pathway, was sequestered in autophagosomes; whereas IRS-2, an adapter protein that transmits IGF-1 signaling through the Akt pathway, was unaffected by cathepsin inhibition. Furthermore, Shc was sequestered in autophagosomes as its active form, indicating that autophagy is a key mechanism for downregulating IGF-1-induced cell proliferation. Cathepsin inhibition had a greater effect on autophagic sequestration of the neuronal specific adapter protein, Shc-C, than ubiquitously expressed Shc-A, providing mechanistic support for the enhanced sensitivity of neuronally derived tumor cells. We also observed impaired activation of MAPK by epidermal growth factor treatment in inhibitor-treated cells. The Shc adapter proteins are central to transducing proliferation signaling by a range of receptor tyrosine kinases; consequently, cathepsin inhibition may become an important therapeutic approach for treating neuroblastoma and other tumors of neuronal origin.

  13. Cathepsin Inhibition Prevents Autophagic Protein Turnover and Downregulates Insulin Growth Factor-1 Receptor–Mediated Signaling in Neuroblastoma

    PubMed Central

    Soori, Mehrnoosh; Lu, Guizhen

    2016-01-01

    Inhibition of the major lysosomal proteases, cathepsins B, D, and L, impairs growth of several cell types but leads to apoptosis in neuroblastoma. The goal of this study was to examine the mechanisms by which enzyme inhibition could cause cell death. Cathepsin inhibition caused cellular accumulation of fragments of the insulin growth factor 1 (IGF-1) receptor. The fragments were located in dense organelles that were characterized as autophagosomes. This novel discovery provides the first clear link between lysosomal function, autophagy, and IGF-1– mediated cell proliferation. A more in-depth analysis of the IGF1 signaling pathway revealed that the mitogen-activated protein kinase (MAPK) cell-proliferation pathway was impaired in inhibitor treated cells, whereas the Akt cell survival pathway remained functional. Shc, an adapter protein that transmits IGF-1 signaling through the MAPK pathway, was sequestered in autophagosomes; whereas IRS-2, an adapter protein that transmits IGF-1 signaling through the Akt pathway, was unaffected by cathepsin inhibition. Furthermore, Shc was sequestered in autophagosomes as its active form, indicating that autophagy is a key mechanism for downregulating IGF-1-induced cell proliferation. Cathepsin inhibition had a greater effect on autophagic sequestration of the neuronal specific adapter protein, Shc-C, than ubiquitously expressed Shc-A, providing mechanistic support for the enhanced sensitivity of neuronally derived tumor cells. We also observed impaired activation of MAPK by epidermal growth factor treatment in inhibitor-treated cells. The Shc adapter proteins are central to transducing proliferation signaling by a range of receptor tyrosine kinases; consequently, cathepsin inhibition may become an important therapeutic approach for treating neuroblastoma and other tumors of neuronal origin. PMID:26660229

  14. Growth Inhibition and Apoptosis Induced by Osthole, A Natural Coumarin, in Hepatocellular Carcinoma

    PubMed Central

    Zhang, Lurong; Jiang, Guorong; Yao, Fei; He, Yan; Liang, Guoqiang; Zhang, Yinsheng; Hu, Bo; Wu, Yan; Li, Yunsen; Liu, Haiyan

    2012-01-01

    Background Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed tumors worldwide and is known to be resistant to conventional chemotherapy. New therapeutic strategies are urgently needed for treating HCC. Osthole, a natural coumarin derivative, has been shown to have anti-tumor activity. However, the effects of osthole on HCC have not yet been reported. Methods and Findings HCC cell lines were treated with osthole at various concentrations for 24, 48 and 72 hours. The proliferations of the HCC cells were measured by MTT assays. Cell cycle distribution and apoptosis were determined by flow cytometry. HCC tumor models were established in mice by subcutaneously injection of SMMC-7721 or Hepa1-6 cells and the effect of osthole on tumor growths in vivo and the drug toxicity were studied. NF-κB activity after osthole treatment was determined by electrophoretic mobility shift assays and the expression of caspase-3 was measured by western blotting. The expression levels of other apoptosis-related genes were also determined by real-time PCR (PCR array) assays. Osthole displayed a dose- and time-dependent inhibition of the HCC cell proliferations in vitro. It also induced apoptosis and caused cell accumulation in G2 phase. Osthole could significantly suppress HCC tumor growth in vivo with no toxicity at the dose we used. NF-κB activity was significantly suppressed by osthole at the dose- and time-dependent manner. The cleaved caspase-3 was also increased by osthole treatment. The expression levels of some apoptosis-related genes that belong to TNF ligand family, TNF receptor family, Bcl-2 family, caspase family, TRAF family, death domain family, CIDE domain and death effector domain family and CARD family were all increased with osthole treatment. Conclusion Osthole could significantly inhibit HCC growth in vitro and in vivo through cell cycle arrest and inducing apoptosis by suppressing NF-κB activity and promoting the expressions of apoptosis

  15. Flavonoids inhibit cell growth and induce apoptosis in B16 melanoma 4A5 cells.

    PubMed

    Iwashita, K; Kobori, M; Yamaki, K; Tsushida, T

    2000-09-01

    We investigated the growth inhibitory activity of several flavonoids, including apigenin, luteolin, kaempherol, quercetin, butein, isoliquiritigenin, naringenin, genistein, and daizein against B16 mouse melanoma 4A5 cells. Isoliquiritigenin and butein, belonging to the chalcone group, markedly suppressed the growth of B16 melanoma cells and induced cell death. The other flavonoids tested showed little growth inhibitory activity and scarcely caused cell death. In cells treated with isoliquiritigenin or butein, condensation of nuclei and fragmentation of nuclear DNA, which are typical phenomena of apoptosis, were observed by Hoechst 33258 staining and by agarose gel electrophoresis of DNA. Flowcytometric analysis showed that isoliquiritigenin and butein increased the proportion of hypodiploid cells in the population of B16 melanoma cells. These results demonstrate that isoliquiritigenin and butein inhibit cell proliferation and induce apoptosis in B16 melanoma cells. Extracellular glucose decreased the proportion of hypodiploid cells that appeared as a result of isoliquiritigenin treatment. p53 was not detected in cells treated with either of these chalcones, however, protein of the Bcl-2 family were detected. The level of expression of Bax in cells treated with either of these chalcones was markedly elevated and the level of Bcl-XL decreased slightly. Isoliquiritigenin did not affect Bcl-2 expression, but butein down-regulated Bcl-2 expression. From these results, it seems that the pathway by which the chalcones induce apoptosis may be independent of p53 and dependent on proteins of the Bcl-2 family. It was supposed that isoliquiritigenin induces apoptosis in B16 cells by a mechanism involving inhibition of glucose transmembrane transport and promotion of Bax expression. On the other hand, it was suggested that butein induces apoptosis via down-regulation of Bcl-2 expression and promotion of Bax expression. This mechanism differs from the isoliquiritigenin induction

  16. An alternative inhibitor overcomes resistance caused by a mutation of the epidermal growth factor receptor.

    PubMed

    Kobayashi, Susumu; Ji, Hongbin; Yuza, Yuki; Meyerson, Matthew; Wong, Kwok-Kin; Tenen, Daniel G; Halmos, Balázs

    2005-08-15

    Mutations of the epidermal growth factor receptor (EGFR) gene have been identified in non-small cell lung cancer specimens from patients responding to anilinoquinazoline EGFR inhibitors. However, clinical resistance to EGFR inhibitor therapy is commonly observed. Previously, we showed that such resistance can be caused by a second mutation of the EGFR gene, leading to a T790M amino acid change in the EGFR tyrosine kinase domain and also found that CL-387,785, a specific and irreversible anilinoquinazoline EGFR inhibitor, was able to overcome this resistance on the biochemical level. Here, we present the successful establishment of a stable Ba/F3 cell line model system for the study of oncogenic EGFR signaling and the functional consequences of the EGFR T790M resistance mutation. We show the ability of gefitinib to induce growth arrest and apoptosis in cells transfected with wild-type or L858R EGFR, whereas the T790M mutation leads to high-level functional resistance against gefitinib and erlotinib. In addition, CL-387,785 is able to overcome resistance caused by the T790M mutation on a functional level, correlating with effective inhibition of downstream signaling pathways. Similar data was also obtained with the use of the gefitinib-resistant H1975 lung cancer cell line. The systems established by us should prove useful for the large-scale screening of alternative EGFR inhibitor compounds against the T790M or other EGFR mutations. These data also support the notion that clinical investigations of compounds similar to CL-387,785 may be useful as a treatment strategy for patients with resistance to EGFR inhibitor therapy caused by the T790M mutation.

  17. Miniaturized Growth Inhibition Assay to Assess the Anti-blood Stage Activity of Antibodies.

    PubMed

    Duncan, Elizabeth H; Bergmann-Leitner, Elke S

    2015-01-01

    While no immune correlate for blood-stage specific immunity against Plasmodium falciparum malaria has been identified, there is strong evidence that antibodies directed to various malarial antigens play a crucial role. In an effort to evaluate the role of antibodies in inhibiting growth and/or invasion of erythrocytic stages of the malaria parasite it will be necessary to test large sample sets from Phase 2a/b trials as well as epidemiological studies. The major constraints for such analyses are (1) availability of sufficient sample quantities (especially from infants and small children) and (2) the throughput of standard growth inhibition assays. The method described here assesses growth- and invasion inhibition by measuring the metabolic activity and viability of the parasite (by using a parasite lactate dehydrogenase-specific substrate) in a 384-microtiter plate format. This culture method can be extended beyond the described detection system to accommodate other techniques commonly used for growth/invasion-inhibition.

  18. Inhibition of prostate cancer growth by muscadine grapeskin extract and resveratrol through distinct mechanisms

    USDA-ARS?s Scientific Manuscript database

    Phytochemicals are naturally occurring compounds with demonstrated anti-tumor activities. The phytochemical resveratrol, contained in red grapes, has been shown to inhibit prostate cancer cell growth, potentially through its anti-oxidant activity. Muscadine grapes contain different phytochemical con...

  19. Ability of Cecal Cultures to Inhibit Growth of Salmonella Typhimurium during Aerobic Incubation

    USDA-ARS?s Scientific Manuscript database

    Introduction: Poultry can serve as reservoirs for Salmonella; however, chicks provided cultures of cecal bacteria develop resistance to colonization by Salmonella. Research has indicated that cecal bacteria metabolize organic acids to produce substances that inhibit Salmonella growth. Purpose: The...

  20. Imatinib mesylate inhibits platelet derived growth factor stimulated proliferation of rheumatoid synovial fibroblasts

    SciTech Connect

    Sandler, Charlotta; Joutsiniemi, Saima; Lindstedt, Ken A.; Juutilainen, Timo; Kovanen, Petri T.; Eklund, Kari K. . E-mail: kari.eklund@hus.fi

    2006-08-18

    Synovial fibroblast is the key cell type in the growth of the pathological synovial tissue in arthritis. Here, we show that platelet-derived growth factor (PDGF) is a potent mitogen for synovial fibroblasts isolated from patients with rheumatoid arthritis. Inhibition of PDGF-receptor signalling by imatinib mesylate (1 {mu}M) completely abrogated the PDGF-stimulated proliferation and inhibited approximately 70% of serum-stimulated proliferation of synovial fibroblasts. Similar extent of inhibition was observed when PDGF was neutralized with anti-PDGF antibodies, suggesting that imatinib mesylate does not inhibit pathways other than those mediated by PDGF-receptors. No signs of apoptosis were detected in synovial fibroblasts cultured in the presence of imatinib. These results suggest that imatinib mesylate specifically inhibits PDGF-stimulated proliferation of synovial fibroblasts, and that inhibition of PDGF-receptors could represent a feasible target for novel antirheumatic therapies.

  1. CDK2 Inhibition Causes Anaphase Catastrophe in Lung Cancer through the Centrosomal Protein CP110

    PubMed Central

    Hu, Shanhu; Danilov, Alexey V.; Godek, Kristina; Orr, Bernardo; Tafe, Laura J.; Rodriguez-Canales, Jaime; Behrens, Carmen; Mino, Barbara; Moran, Cesar A.; Memoli, Vincent A.; Mustachio, Lisa Maria; Galimberti, Fabrizio; Ravi, Saranya; DeCastro, Andrew; Lu, Yun; Sekula, David; Andrew, Angeline S; Wistuba, Ignacio I.; Freemantle, Sarah; Compton, Duane A.; Dmitrovsky, Ethan

    2015-01-01

    Aneuploidy is frequently detected in human cancers and is implicated in carcinogenesis. Pharmacological targeting of aneuploidy is an attractive therapeutic strategy as this would preferentially eliminate malignant over normal cells. We previously discovered that CDK2 inhibition causes lung cancer cells with more than two centrosomes to undergo multipolar cell division leading to apoptosis, defined as anaphase catastrophe. Cells with activating KRAS mutations were especially sensitive to CDK2 inhibition. Mechanisms of CDK2-mediated anaphase catastrophe and how activated KRAS enhances this effect were investigated. Live-cell imaging provided direct evidence that following CDK2 inhibition, lung cancer cells develop multipolar anaphase and undergo multipolar cell division with the resulting progeny apoptotic. Small interfering RNA (siRNA)-mediated repression of the CDK2 target and centrosome protein CP110 induced anaphase catastrophe of lung cancer cells. In contrast, CP110 overexpression antagonized CDK2 inhibitor-mediated anaphase catastrophe. Furthermore, activated KRAS mutations sensitized lung cancer cells to CDK2 inhibition by deregulating CP110 expression. Thus, CP110 is a critical mediator of CDK2-inhibition-driven anaphase catastrophe. Independent examination of murine and human paired normal-malignant lung tissues revealed marked upregulation of CP110 in malignant versus normal lung. Human lung cancers with KRAS mutations had significantly lower CP110 expression as compared to KRAS wild-type cancers. Thus, a direct link was found between CP110 and CDK2 inhibitor antineoplastic response. CP110 plays a mechanistic role in response of lung cancer cells to CDK2 inhibition, especially in the presence of activated KRAS mutations. PMID:25808870

  2. Di-(2-ethylhexyl) phthalate and mono-(2-ethylhexyl) phthalate inhibit growth and reduce estradiol levels of antral follicles in vitro

    SciTech Connect

    Gupta, Rupesh K.; Singh, Jeffery M.; Leslie, Tracie C.; Meachum, Sharon; Flaws, Jodi A.; Yao, Humphrey H-C

    2010-01-15

    Any insult that affects survival of ovarian antral follicles can cause abnormal estradiol production and fertility problems. Phthalate esters (PEs) are plasticizers used in a wide range of consumer and industrial products. Exposure to these chemicals has been linked to reduced fertility in humans and animal models. Di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) decrease serum estradiol levels and aromatase (Arom) expression, prolong estrous cycles, and cause anovulation in animal and culture models. These observations suggest PEs directly target antral follicles. We therefore tested the hypothesis that DEHP (1-100 mug/ml) and MEHP (0.1-10 mug/ml) directly inhibit antral follicular growth and estradiol production. Antral follicles from adult mice were cultured with DEHP or MEHP, and/or estradiol for 96 h. During culture, follicle size was measured every 24 h as a measurement of follicle growth. After culture, media were collected for measurement of estradiol levels and follicles were subjected to measurement of cylin-D-2 (Ccnd2), cyclin-dependant-kinase-4 (Cdk4), and Arom. We found that DEHP and MEHP inhibited growth of follicles and decreased estradiol production compared to controls at the highest doses. DEHP and MEHP also decreased mRNA expression of Ccnd2, Cdk4, and Arom at the highest dose. Addition of estradiol to the culture medium prevented the follicles from DEHP- and MEHP-induced inhibition of growth, reduction in estradiol levels, and decreased Ccnd2 and Cdk4 expression. Collectively, our results indicate that DEHP and MEHP may directly inhibit antral follicle growth via a mechanism that partially includes reduction in levels of estradiol production and decreased expression of cell cycle regulators.

  3. Rottlerin inhibits cell growth and invasion via down-regulation of Cdc20 in glioma cells

    PubMed Central

    Wang, Lixia; Hou, Yingying; Yin, Xuyuan; Su, Jingna; Zhao, Zhe; Ye, Xiantao; Zhou, Xiuxia; Zhou, Li; Wang, Zhiwei

    2016-01-01

    Rottlerin, isolated from a medicinal plant Mallotus phillippinensis, has been demonstrated to inhibit cellular growth and induce cytoxicity in glioblastoma cell lines through inhibition of calmodulin-dependent protein kinase III. Emerging evidence suggests that rottlerin exerts its antitumor activity as a protein kinase C inhibitor. Although further studies revealed that rottlerin regulated multiple signaling pathways to suppress tumor cell growth, the exact molecular insight on rottlerin-mediated tumor inhibition is not fully elucidated. In the current study, we determine the function of rottlerin on glioma cell growth, apoptosis, cell cycle, migration and invasion. We found that rottlerin inhibited cell growth, migration, invasion, but induced apoptosis and cell cycle arrest. Mechanistically, the expression of Cdc20 oncoprotein was measured by the RT-PCR and Western blot analysis in glioma cells treated with rottlerin. We observed that rottlerin significantly inhibited the expression of Cdc20 in glioma cells, implying that Cdc20 could be a novel target of rottlerin. In line with this, over-expression of Cdc20 decreased rottlerin-induced cell growth inhibition and apoptosis, whereas down-regulation of Cdc20 by its shRNA promotes rottlerin-induced anti-tumor activity. Our findings indicted that rottlerin could exert its tumor suppressive function by inhibiting Cdc20 pathway which is constitutively active in glioma cells. Therefore, down-regulation of Cdc20 by rottlerin could be a promising therapeutic strategy for the treatment of glioma. PMID:27626499

  4. Volatile Fatty Acids and the Inhibition of Escherichia coli Growth by Rumen Fluid1

    PubMed Central

    Wolin, Meyer J.

    1969-01-01

    Concentrations of volatile fatty acids (VFA) normally found in bovine rumen fluid inhibited growth of Escherichia coli in Antibiotic Medium 3. Acetic, propionic, and butyric acids each produced growth inhibition which was markedly pH-dependent. Little inhibition was observed at pH 7.0, and inhibition increased with decreasing pH. A combination of 60 μmoles of acetate, 20 μmoles of propionate, and 15 μmoles of butyrate per ml gave 96, 69, and 2% inhibition at pH 6.0, 6.5, and 7.0, respectively. Rumen fluid (50%) gave 89 and 48% inhibition at pH 6.0 and 6.5, respectively, and growth stimulation (22%) at pH 7.0. Rumen fluid inhibitory activity was heat-stable, was not precipitated by 63% ethyl alcohol, and was lost by dialysis and by treatment with anion-exchange resins but not with cation-exchange resins. These results are consistent with the idea that VFA are the inhibitory substances in rumen fluid. Previous results which indicated that rumen fluid VFA did not inhibit E. coli growth were due to lack of careful control of the final pH of the growth medium. The E. coli strain used does not grow in rumen fluid alone at pH 7.0. PMID:4886864

  5. Nicotine-induced retardation of chondrogenesis through down-regulation of IGF-1 signaling pathway to inhibit matrix synthesis of growth plate chondrocytes in fetal rats

    SciTech Connect

    Deng, Yu; Cao, Hong; Cu, Fenglong; Xu, Dan; Lei, Youying; Tan, Yang; Magdalou, Jacques; Wang, Hui; Chen, Liaobin

    2013-05-15

    Previous studies have confirmed that maternal tobacco smoking causes intrauterine growth retardation (IUGR) and skeletal growth retardation. Among a multitude of chemicals associated with cigarette smoking, nicotine is one of the leading candidates for causing low birth weights. However, the possible mechanism of delayed chondrogenesis by prenatal nicotine exposure remains unclear. We investigated the effects of nicotine on fetal growth plate chondrocytes in vivo and in vitro. Rats were given 2.0 mg/kg·d of nicotine subcutaneously from gestational days 11 to 20. Prenatal nicotine exposure increased the levels of fetal blood corticosterone and resulted in fetal skeletal growth retardation. Moreover, nicotine exposure induced the inhibition of matrix synthesis and down-regulation of insulin-like growth factor 1 (IGF-1) signaling in fetal growth plates. The effects of nicotine on growth plates were studied in vitro by exposing fetal growth plate chondrocytes to 0, 1, 10, or 100 μM of nicotine for 10 days. Nicotine inhibited matrix synthesis and down-regulated IGF-1 signaling in chondrocytes in a concentration-dependent manner. These results suggest that prenatal nicotine exposure induces delayed chondrogenesis and that the mechanism may involve the down-regulation of IGF-1 signaling and the inhibition of matrix synthesis by growth plate chondrocytes. The present study aids in the characterization of delayed chondrogenesis caused by prenatal nicotine exposure, which might suggest a candidate mechanism for intrauterine origins of osteoporosis and osteoarthritis. - Highlights: ► Prenatal nicotine-exposure could induce delayed chondrogenesis in fetal rats. ► Nicotine inhibits matrix synthesis of fetal growth plate chondrocytes. ► Nicotine inhibits IGF-1 signaling pathway in fetal growth plate chondrocytes.

  6. Mechanisms of Chinese Red Yeast Rice Inhibition of Prostate Cancer Growth

    DTIC Science & Technology

    2009-04-01

    cou- pled with a model 490E Programmable Multiwavelength UV detector (Waters Corp., Milford, MA) with conditions as follows: column, Phenomenex...5.93 M MK, and this led to 47% and 77% inhibition of LNCaP and 62% and 65% inhibition of LNCaP-AR cell growth in 48 and 72 hours of treatments

  7. Mechanisms of Chinese Red Yeast Rice Inhibition of Prostate Cancer Growth

    DTIC Science & Technology

    2009-10-01

    extract onto a Prep-LC 4000 system cou- pled with a model 490E Programmable Multiwavelength UV detector (Waters Corp., Milford, MA) with conditions as...mL RYR provides a concentration of 5.93 M MK, and this led to 47% and 77% inhibition of LNCaP and 62% and 65% inhibition of LNCaP-AR cell growth in

  8. Inhibition of Growth of Salmonella by Native Flora of Broiler Chickens

    USDA-ARS?s Scientific Manuscript database

    Introduction Some bacteria in the cecal microflora of broilers can inhibit colonization of chicks by Salmonella. Beneficial cecal bacteria may reduce Salmonella colonization by competing for nutrients and attachment sites or by producing metabolites that inhibit Salmonella growth. The purpose of th...

  9. The non-steroidal anti-inflammatory drug niflumic acid inhibits Candida albicans growth.

    PubMed

    Baker, Andrew; Northrop, Frederick D; Miedema, Hendrik; Devine, Gary R; Davies, Julia M

    2002-01-01

    The non-steroidal anti-inflammatory drug niflumic acid was found to inhibit growth of the yeast form of Candida albicans. Niflumic acid inhibited respiratory oxygen uptake and it is hypothesised that this was achieved by cytosolic acidification and block of glycolysis. Inhibitory concentrations are compatible with current practice of topical application.

  10. Receptor tyrosine kinase inhibition causes simultaneous bone loss and excess bone formation within growing bone in rats

    SciTech Connect

    Nurmio, Mirja; Joki, Henna; Kallio, Jenny; Maeaettae, Jorma A.; Vaeaenaenen, H. Kalervo; Toppari, Jorma; Jahnukainen, Kirsi; Laitala-Leinonen, Tiina

    2011-08-01

    During postnatal skeletal growth, adaptation to mechanical loading leads to cellular activities at the growth plate. It has recently become evident that bone forming and bone resorbing cells are affected by the receptor tyrosine kinase (RTK) inhibitor imatinib mesylate (STI571, Gleevec (registered)) . Imatinib targets PDGF, ABL-related gene, c-Abl, c-Kit and c-Fms receptors, many of which have multiple functions in the bone microenvironment. We therefore studied the effects of imatinib in growing bone. Young rats were exposed to imatinib (150 mg/kg on postnatal days 5-7, or 100 mg/kg on postnatal days 5-13), and the effects of RTK inhibition on bone physiology were studied after 8 and 70 days (3-day treatment), or after 14 days (9-day treatment). X-ray imaging, computer tomography, histomorphometry, RNA analysis and immunohistochemistry were used to evaluate bone modeling and remodeling in vivo. Imatinib treatment eliminated osteoclasts from the metaphyseal osteochondral junction at 8 and 14 days. This led to a resorption arrest at the growth plate, but also increased bone apposition by osteoblasts, thus resulting in local osteopetrosis at the osteochondral junction. The impaired bone remodelation observed on day 8 remained significant until adulthood. Within the same bone, increased osteoclast activity, leading to bone loss, was observed at distal bone trabeculae on days 8 and 14. Peripheral quantitative computer tomography (pQCT) and micro-CT analysis confirmed that, at the osteochondral junction, imatinib shifted the balance from bone resorption towards bone formation, thereby altering bone modeling. At distal trabecular bone, in turn, the balance was turned towards bone resorption, leading to bone loss. - Research Highlights: > 3-Day imatinib treatment. > Causes growth plate anomalies in young rats. > Causes biomechanical changes and significant bone loss at distal trabecular bone. > Results in loss of osteoclasts at osteochondral junction.

  11. Inhibition of mycobacterial growth in vitro following primary but not secondary vaccination with Mycobacterium bovis BCG.

    PubMed

    Fletcher, Helen A; Tanner, Rachel; Wallis, Robert S; Meyer, Joel; Manjaly, Zita-Rose; Harris, Stephanie; Satti, Iman; Silver, Richard F; Hoft, Dan; Kampmann, Beate; Walker, K Barry; Dockrell, Hazel M; Fruth, Uli; Barker, Lew; Brennan, Michael J; McShane, Helen

    2013-11-01

    Despite the widespread use of the Mycobacterium bovis BCG vaccine, there are more than 9 million new cases of tuberculosis (TB) every year, and there is an urgent need for better TB vaccines. TB vaccine candidates are selected for evaluation based in part on the detection of an antigen-specific gamma interferon (IFN-γ) response. The measurement of mycobacterial growth in blood specimens obtained from subjects immunized with investigational TB vaccines may be a better in vitro correlate of in vivo vaccine efficacy. We performed a clinical study with 30 United Kingdom adults who were followed for 6 months to evaluate the abilities of both a whole-blood- and a novel peripheral blood mononuclear cell (PBMC)-based mycobacterial growth inhibition assay to measure a response to primary vaccination and revaccination with BCG. Using cryopreserved PBMCs, we observed a significant improvement in mycobacterial growth inhibition following primary vaccination but no improvement in growth inhibition following revaccination with BCG (P < 0.05). Mycobacterial growth inhibition following primary BCG vaccination was not correlated with purified protein derivative (PPD) antigen-specific IFN-γ enzyme-linked immunospot (ELISPOT) responses. We demonstrate that a mycobacterial growth inhibition assay can detect improved capacity to control growth following primary immunization, but not revaccination, with BCG. This is the first study to demonstrate that an in vitro growth inhibition assay can identify a difference in vaccine responses by comparing both primary and secondary BCG vaccinations, suggesting that in vitro growth inhibition assays may serve as better surrogates of clinical efficacy than the assays currently used for the assessment of candidate TB vaccines.

  12. ABD56 causes osteoclast apoptosis by inhibiting the NF{kappa}B and ERK pathways

    SciTech Connect

    Idris, Aymen; Mrak, Emanuela; Greig, Iain; Guidobono, Francesca; Ralston, Stuart H.; Hof, Rob van 't

    2008-06-20

    We have previously shown that the biphenylcarboxylic acid butanediol ester (ABD56) inhibits osteoclast formation and activity in vitro and in vivo. However, the mechanism of action of this compound is unknown. ABD56 inhibited osteoclast formation and caused osteoclast apoptosis, but had no effects on osteoblasts or macrophages. As the NF{kappa}B and MAPK pathways are essential for osteoclast formation and survival, we studied the effects of ABD56 on these pathways. ABD56 caused phosphorylation of p38, JNK and nuclear translocation of c-jun in osteoclasts. ABD56-induced apoptosis was prevented by the caspase inhibitor zVAD-fmk but was not prevented by the p38- or JNK-inhibitors. ABD56 completely abolished RANKL-induced I{kappa}B and ERK1/2 phosphorylation. Increasing the amount of RANKL partially rescued ABD56-induced apoptosis, indicating that the apoptosis is most probably due to the inhibition of survival signals such as ERK and NF{kappa}B, rather than activation of the p38 or Jnk MAPK pathways.

  13. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia

    PubMed Central

    Bohnert, Kyle R.; Gallot, Yann S.; Sato, Shuichi; Xiong, Guangyan; Hindi, Sajedah M.; Kumar, Ashok

    2016-01-01

    Cachexia is a devastating syndrome that causes morbidity and mortality in a large number of patients with cancer. However, the mechanisms of cancer cachexia remain poorly understood. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes stress. The ER responds to this stress through activating certain pathways commonly known as the unfolding protein response (UPR). The main function of UPR is to restore homeostasis, but excessive or prolonged activation of UPR can lead to pathologic conditions. In this study, we examined the role of ER stress and UPR in regulation of skeletal muscle mass in naïve conditions and during cancer cachexia. Our results demonstrate that multiple markers of ER stress are highly activated in skeletal muscle of Lewis lung carcinoma (LLC) and ApcMin/+ mouse models of cancer cachexia. Treatment of mice with 4-phenylbutyrate (4-PBA), a chemical chaperon and a potent inhibitor of ER stress, significantly reduced skeletal muscle strength and mass in both control and LLC-bearing mice. Blocking the UPR also increased the proportion of fast-type fibers in soleus muscle of both control and LLC-bearing mice. Inhibition of UPR reduced the activity of Akt/mTOR pathway and increased the expression of the components of the ubiquitin–proteasome system and autophagy in LLC-bearing mice. Moreover, we found that the inhibition of UPR causes severe atrophy in cultured myotubes. Our study provides initial evidence that ER stress and UPR pathways are essential for maintaining skeletal muscle mass and strength and for protection against cancer cachexia.—Bohnert, K. R., Gallot, Y. S., Sato, S., Xiong, G., Hindi, S. M., Kumar, A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia. PMID:27206451

  14. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia.

    PubMed

    Bohnert, Kyle R; Gallot, Yann S; Sato, Shuichi; Xiong, Guangyan; Hindi, Sajedah M; Kumar, Ashok

    2016-09-01

    Cachexia is a devastating syndrome that causes morbidity and mortality in a large number of patients with cancer. However, the mechanisms of cancer cachexia remain poorly understood. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes stress. The ER responds to this stress through activating certain pathways commonly known as the unfolding protein response (UPR). The main function of UPR is to restore homeostasis, but excessive or prolonged activation of UPR can lead to pathologic conditions. In this study, we examined the role of ER stress and UPR in regulation of skeletal muscle mass in naïve conditions and during cancer cachexia. Our results demonstrate that multiple markers of ER stress are highly activated in skeletal muscle of Lewis lung carcinoma (LLC) and Apc(Min/+) mouse models of cancer cachexia. Treatment of mice with 4-phenylbutyrate (4-PBA), a chemical chaperon and a potent inhibitor of ER stress, significantly reduced skeletal muscle strength and mass in both control and LLC-bearing mice. Blocking the UPR also increased the proportion of fast-type fibers in soleus muscle of both control and LLC-bearing mice. Inhibition of UPR reduced the activity of Akt/mTOR pathway and increased the expression of the components of the ubiquitin-proteasome system and autophagy in LLC-bearing mice. Moreover, we found that the inhibition of UPR causes severe atrophy in cultured myotubes. Our study provides initial evidence that ER stress and UPR pathways are essential for maintaining skeletal muscle mass and strength and for protection against cancer cachexia.-Bohnert, K. R., Gallot, Y. S., Sato, S., Xiong, G., Hindi, S. M., Kumar, A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia. © FASEB.

  15. Impaired plant growth and development caused by human immunodeficiency virus type 1 Tat.

    PubMed

    Cueno, Marni E; Hibi, Yurina; Imai, Kenichi; Laurena, Antonio C; Okamoto, Takashi

    2010-10-01

    Previous attempts to express the human immunodeficiency virus 1 (HIV-1) Tat (trans-activator of transcription) protein in plants resulted in a number of physiological abnormalities, such as stunted growth and absence of seed formation, that could not be explained. In the study reported here, we expressed Tat in tomato and observed phenotypic abnormalities, including stunted growth, absence of root formation, chlorosis, and plant death, as a result of reduced cytokinin levels. These reduced levels were ascribed to a differentially expressed CKO35 in Tat-bombarded tomato. Of the two CKO isoforms that are naturally expressed in tomato, CKO43 and CKO37, only the expression of CKO37 was affected by Tat. Our analysis of the Tat confirmed that the Arg-rich and RGD motifs of Tat have functional relevance in tomato and that independent mutations at these motifs caused inhibition of the differentially expressed CKO isoform and the extracellular secretion of the Tat protein, respectively, in our Tat-bombarded tomato samples.

  16. In vitro Plasmodium falciparum drug sensitivity assay: inhibition of parasite growth by incorporation of stomatocytogenic amphiphiles into the erythrocyte membrane.

    PubMed

    Ziegler, Hanne L; Staerk, Dan; Christensen, Jette; Hviid, Lars; Hägerstrand, Henry; Jaroszewski, Jerzy W

    2002-05-01

    Lupeol, which shows in vitro inhibitory activity against Plasmodium falciparum 3D7 strain with a 50% inhibitory concentration (IC50) of 27.7 +/- 0.5 microM, was shown to cause a transformation of the human erythrocyte shape toward that of stomatocytes. Good correlation between the IC50 value and the membrane curvature changes caused by lupeol was observed. Preincubation of erythrocytes with lupeol, followed by extensive washing, made the cells unsuitable for parasite growth, suggesting that the compound incorporates into erythrocyte membrane irreversibly. On the other hand, lupeol-treated parasite culture continued to grow well in untreated erythrocytes. Thus, the antiplasmodial activity of lupeol appears to be indirect, being due to stomatocytic transformation of the host cell membrane and not to toxic effects via action on a drug target within the parasite. A number of amphiphiles that cause stomatocyte formation, but not those causing echinocyte formation, were shown to inhibit growth of the parasites, apparently via a mechanism similar to that of lupeol. Since antiplasmodial agents that inhibit parasite growth through erythrocyte membrane modifications must be regarded as unsuitable as leads for development of new antimalarial drugs, care must be exercised in the interpretation of results of screening of plant extracts and natural product libraries by an in vitro Plasmodium toxicity assay.

  17. Aspergillus flavus growth inhibition by Lactobacillus strains isolated from traditional fermented Kenyan milk and maize products.

    PubMed

    Ahlberg, Sara; Joutsjoki, Vesa; Laurikkala, Sini; Varmanen, Pekka; Korhonen, Hannu

    2017-04-01

    Certain strains of lactic acid bacteria have been reported to inhibit fungal growth and may so be potential as biocontrol agents. In this study, 171 LAB strains were isolated from traditional fermented Kenyan milk and maize products and tested against aflatoxin-producing A. flavus fungi. The three LAB strains showing highest antifungal activity were identified as Lactobacillus plantarum. None of the strains were able to completely inhibit fungal growth under conditions favorable for fungi and suboptimal for LAB. These conditions probably reduced the growth and metabolic activity of some LAB isolates, as several growth-related aspects like production of antifungal biomolecules and other metabolites contribute to the inhibiting activity. The results suggest that certain LAB strains could be employed in food to control the growth of aflatoxigenic fungi. Further studies to establish the efficacy of the potential LAB strains in fermented products are in progress.

  18. (-)-Anonaine induces DNA damage and inhibits growth and migration of human lung carcinoma h1299 cells.

    PubMed

    Chen, Bing-Hung; Chang, Hsueh-Wei; Huang, Hsuan-Min; Chong, Inn-Wen; Chen, Jia-Shing; Chen, Chung-Yi; Wang, Hui-Min

    2011-03-23

    The anticancer effects of (-)-anonaine were investigated in this current study. (-)-Anonaine at concentration ranges of 50-200 μM exhibited significant inhibition to cell growth and migration activities on human lung cancer H1299 cells at 24 h, albeit cell cycle analyses showed that (-)-anonaine at the above concentration ranges did not cause any significant changes in cell-cycle distributions. Significant nuclear damages of H1299 cells were observed with 10-200 μM (-)-anonaine treatment in a comet assay, whereas higher concentrations (6 and 30 mM) of (-)-anonaine concentrations were required to cause DNA damages in an in vitro plasmid cleavage assay. In summary, our results demonstrated that (-)-anonaine exhibited dose-dependent antiproliferatory, antimigratory, and DNA-damaging effects on H1299 cells. We inferred that (-)-anonaine can cause cell-cycle arrest and DNA damage to hamper the physiological behavior of cancer cells at 72 h, and therefore, it can be useful as one of the potential herbal supplements for chemoprevention of human lung cancer.

  19. Enhancing chemotherapeutic drug inhibition on tumor growth by ultrasound: an in vivo experiment.

    PubMed

    Zhao, Ying-Zheng; Lu, Cui-Tao; Zhou, Zhi-Cai; Jin, Zhuo; Zhang, Lu; Sun, Chang-Zheng; Xu, Yan-Yan; Gao, Hui-Sheng; Tian, Ji-Lai; Gao, Feng-Hou; Tang, Qin-Qin; Li, Wei; Xiang, Qi; Li, Xiao-Kun; Li, Wen-Feng

    2011-02-01

    An in vivo study on enhancing epirubicin hydrochloride (EPI) inhibition on tumor growth by ultrasound (US) was reported. Five-week-old male nude mice were used and HL-60 cells were s.c. (subcutaneous injection) inoculated in axilla of these mice. Six groups were designed and five consecutive treatments were applied to investigate the inhibition on tumor growth and body weight growth. US applied locally to the tumor resulted in a substantially increased drug uptake in tumor cells. The inhibition on tumor growth depended on the position of drug injection and phospholipid-based microbubble (PMB) application. Tumor growth rate under group 1 (PMB+US) was similar to that of blank control. The order of the inhibition on tumor volume growth was: group 4 (s.c. EPI+PMB+US) > group 5 intraperitoneal (i.p. EPI+PMB+US) > group 2 (i.p. EPI) > group 3 (s.c. EPI+US) > group 1 (PMB+US). Similar conclusion was obtained from experimental measurements of tumor weight change. The order of animal survival status for EPI administration groups was: group 4 > group 5 > group 2 > group 3. Chemotherapeutic drug inhibition on tumor growth could be enhanced by local US combined with PMB, which might provide a potential application for US-mediated chemotherapy.

  20. Hyaluronic acid inhibits the adherence and growth of monolayer keratinocytes but does not affect the growth of keratinocyte epithelium.

    PubMed

    Harvima, Ilkka T; Heikura, Hanna; Hyttinen, Mika; Naukkarinen, Anita

    2006-10-01

    Hyaluronic acid (HA) is involved in epidermal biology but evidence for its functional significance is sparse. In this study, low-calcium monolayer and high-calcium epithelium cultures of human keratinocytes were used to study the effect of up to four different HA preparations on keratinocyte growth and on the adherence of proliferating keratinocytes onto the plastic surface coated with different matrix proteins. In suboptimally growing monolayer culture, up to 1,000 microg/ml rooster comb HA and streptococcus equi HA inhibited keratinocyte growth. Instead, all HA preparations tested did not affect the growth and migration of keratinocyte epithelium using optimal or suboptimal growth conditions. In the cell adherence assays, up to 1,000 microg/ml rooster comb HA and streptococcus equi HA inhibited the keratinocyte adherence onto the fibronectin- and collagen-coated substratum. In contrast to other HA preparations, HA from human umbilical cord did not affect the growth of monolayer keratinocytes and it increased markedly the cell adherence onto the collagen-coated substratum. This increase, however, can be attributed to chonroitin sulphate proteoglycan contaminant present in this HA preparation. In conclusion, HA can inhibit the growth and adherence of proliferating monolayer keratinocytes, but it has no apparent effect on the growth and migration of keratinocyte epithelium.

  1. The slowdown in population growth: causes and consequences.

    PubMed

    Willmann, H; Hoyt, S

    1989-01-01

    U.S. population trends are projected using data from the Bureau of the Census. The focus is on the economic consequences of these trends. The authors conclude that the economic impact will be relatively slight up to the year 2000. "After 2000, the changes to the economic outlook will be more significant. The aging of the population will accelerate and the pace of economic growth is likely to slow even further. More resources will be devoted to caring for the elderly, while public and private pension systems will need to draw down savings to provide for the retirement of the baby-boom generation." excerpt

  2. Replication-induced DNA damage after PARP inhibition causes G2 delay, and cell line-dependent apoptosis, necrosis and multinucleation

    PubMed Central

    Dale Rein, Idun; Solberg Landsverk, Kirsti; Micci, Francesca; Patzke, Sebastian; Stokke, Trond

    2015-01-01

    PARP inhibitors have been approved for treatment of tumors with mutations in or loss of BRCA1/2. The molecular mechanisms and particularly the cellular phenotypes resulting in synthetic lethality are not well understood and varying clinical responses have been observed. We have investigated the dose- and time-dependency of cell growth, cell death and cell cycle traverse of 4 malignant lymphocyte cell lines treated with the PARP inhibitor Olaparib. PARP inhibition induced a severe growth inhibition in this cell line panel and increased the levels of phosphorylated H2AX-associated DNA damage in S phase. Repair of the remaining replication related damage caused a G2 phase delay before entry into mitosis. The G2 delay, and the growth inhibition, was more pronounced in the absence of functional ATM. Further, Olaparib treated Reh and Granta-519 cells died by apoptosis, while U698 and JVM-2 cells proceeded through mitosis with aberrant chromosomes, skipped cytokinesis, and eventually died by necrosis. The TP53-deficient U698 cells went through several rounds of DNA replication and mitosis without cytokinesis, ending up as multinucleated cells with DNA contents of up to 16c before dying. In summary, we report here for the first time cell cycle-resolved DNA damage induction, and cell line-dependent differences in the mode of cell death caused by PARP inhibition. PMID:26312527

  3. Lupeol, a dietary triterpene, inhibited growth, and induced apoptosis through down-regulation of DR3 in SMMC7721 cells.

    PubMed

    Zhang, Lin; Zhang, Youcheng; Zhang, Lingyi; Yang, Xiaojun; Lv, Zhicheng

    2009-02-01

    Lupeol (Lup-20(29)-en-3H-ol), a novel dietary triterpene, was found in fruits, vegetables, and several medicinal plants. Here, we investigated its growth-inhibitory effect and associated mechanisms in hepatocellular carcinoma SMMC7721 cells. Lupeol treatment resulted in significant inhibition of cell viability in a dose-dependent manner and caused apoptotic death of this cell line with activation of caspase3 expression. Caspase8 inhibitor pretreatment was found to partially block the apoptosis induced by Lupeol. Moreover, Lupeol specifically caused a significant decrease in the expression of Death receptor 3 (DR3) mRNA and protein and a significant elevated expression of FADD mRNA whereas Fas mRNA and protein expression was not detectable. Further more, knockdown of DR3 by small interfering RNA inhibited the growth and induced apoptosis of hepatocellular carcinoma cell. These results suggested that Lupeol treatment induced growth inhibition and apoptosis in SMMC7721 cells, the mechanism is due to down-regulation of DR3 expression. We demonstrated that Lupeol appears to be a promising chemopreventive agent for treating hepatocellular carcinoma, and DR3 may be an important target for liver cancer therapy.

  4. Boric Acid Inhibition of Trichophyton rubrum Growth and Conidia Formation.

    PubMed

    Schmidt, Martin

    2017-04-08

    Trichophyton rubrum is a common human dermatophyte that is the causative agent of 80-93% of fungal infections of the skin and nails. While dermatophyte infections in healthy people are easily treatable with over-the-counter medications, such infections pose a higher risk for patients with compromised immune function and impaired regenerative potential. The efficacy of boric acid (BA) for the treatment of vaginal yeast infections prompted an investigation of the effect of BA on growth and morphology of T. rubrum. This is of particular interest since BA facilitates wound healing, raising the possibility that treating athlete's foot with BA, either alone or in combination with other antifungal drugs, would combine the benefits of antimicrobial activity and tissue regeneration to accelerate healing of infected skin. The data presented here show that BA represses T. rubrum growth at a concentration reported to be beneficial for host tissue regeneration. Oxygen exposure increases BA toxicity, and mycelia growing under BA stress avoid colonizing the surface of the growth surface, which leads to a suppression of aerial mycelium growth and surface conidia formation. BA penetrates into solid agar matrices, but the relative lack of oxygen below the substrate surface limits the effectiveness of BA in suppressing growth of embedded T. rubrum cells.

  5. Ivermectin Inhibits Growth of Chlamydia trachomatis in Epithelial Cells

    PubMed Central

    Pettengill, Matthew A.; Lam, Verissa W.; Ollawa, Ikechukwu; Marques-da-Silva, Camila; Ojcius, David M.

    2012-01-01

    Ivermectin is currently approved for treatment of both clinical and veterinary infections by nematodes, including Onchocerca cervicalis in horses and Onchocerca volvulus in humans. However, ivermectin has never been shown to be effective against bacterial pathogens. Here we show that ivermectin also inhibits infection of epithelial cells by the bacterial pathogen, Chlamydia trachomatis, at doses that could be envisioned clinically for sexually-transmitted or ocular infections by Chlamydia. PMID:23119027

  6. Inhibition of Streptococcus mutans Growth and Biofilm Formation by Probiotics in vitro.

    PubMed

    Schwendicke, Falk; Korte, Franziska; Dörfer, Christof E; Kneist, Susanne; Fawzy El-Sayed, Karim; Paris, Sebastian

    2017-01-01

    To exert anticaries effects, probiotics are described to inhibit growth and biofilm formation of cariogenic bacteria such as Streptococcus mutans (SM). We screened 8 probiotics and assessed how SM growth or biofilm formation inhibition affects cariogenicity of probiotic-SM mixed-species biofilms in vitro. Growth inhibition was assessed by cocultivating probiotics and 2 SM strains (ATCC 20532/25175) on agar. Probiotics were either precultured before SM cultivation (exclusion), or SM precultured prior to probiotic cultivation (displacement). Inhibition of SM culture growth was assessed visually. Inhibition of SM biofilm formation on bovine enamel was assessed using a continuous-flow short-term biofilm model, again in exclusion or displacement mode. The cariogenicity of mixed-species biofilms of SM with the most promising growth and biofilm formation inhibiting probiotic strains was assessed using an artificial mouth model, and enamel mineral loss (ΔZ) was measured microradiographically. We found limited differences in SM growth inhibition in exclusion versus displacement mode, and in inhibition of SM 20532 versus 25175. Results were therefore pooled. Lactobacillus acidophilus LA-5 inhibited significantly more SM culture growth than most other probiotics. L. casei LC-11 inhibited SM biofilm formation similarly to other alternatives but showed the highest retention of probiotics in the biofilms (p < 0.05). Mineral loss from SM monospecies biofilms (ΔZ = 9,772, 25th/75th percentiles: 6,277/13,558 vol% × µm) was significantly lower than from mixed-species SM × LA-5 biofilms (ΔZ = 24,578, 25th/75th percentiles: 19,081/28,768 vol% × µm; p < 0.01) but significantly higher than from SM × LC-11 biofilms (ΔZ = 4,835, 25th/75th percentiles: 263/7,865 vol% × µm; p < 0.05). Probiotics inhibiting SM culture growth do not necessarily reduce the cariogenicity of SM-probiotic biofilms. Nevertheless, SM biofilm formation inhibition may be relevant in the reduction of

  7. Niclosamide Prevents the Formation of Large Ubiquitin-Containing Aggregates Caused by Proteasome Inhibition

    PubMed Central

    Winget, Jason M.; Brack, Maria; Rotblat, Barak; Novoa, Carolina Arias; Balgi, Aruna D.; Sorensen, Poul H.; Roberge, Michel; Mayor, Thibault

    2010-01-01

    Background Protein aggregation is a hallmark of many neurodegenerative diseases and has been linked to the failure to degrade misfolded and damaged proteins. In the cell, aberrant proteins are degraded by the ubiquitin proteasome system that mainly targets short-lived proteins, or by the lysosomes that mostly clear long-lived and poorly soluble proteins. Both systems are interconnected and, in some instances, autophagy can redirect proteasome substrates to the lysosomes. Principal Findings To better understand the interplay between these two systems, we established a neuroblastoma cell population stably expressing the GFP-ubiquitin fusion protein. We show that inhibition of the proteasome leads to the formation of large ubiquitin-containing inclusions accompanied by lower solubility of the ubiquitin conjugates. Strikingly, the formation of the ubiquitin-containing aggregates does not require ectopic expression of disease-specific proteins. Moreover, formation of these focused inclusions caused by proteasome inhibition requires the lysine 63 (K63) of ubiquitin. We then assessed selected compounds that stimulate autophagy and found that the antihelmintic chemical niclosamide prevents large aggregate formation induced by proteasome inhibition, while the prototypical mTORC1 inhibitor rapamycin had no apparent effect. Niclosamide also precludes the accumulation of poly-ubiquitinated proteins and of p62 upon proteasome inhibition. Moreover, niclosamide induces a change in lysosome distribution in the cell that, in the absence of proteasome activity, may favor the uptake into lysosomes of ubiquitinated proteins before they form large aggregates. Conclusions Our results indicate that proteasome inhibition provokes the formation of large ubiquitin containing aggregates in tissue culture cells, even in the absence of disease specific proteins. Furthermore our study suggests that the autophagy-inducing compound niclosamide may promote the selective clearance of ubiquitinated

  8. Lack of reproducible growth inhibition by Schlafen1 and Schlafen2 in vitro.

    PubMed

    Zhao, Liang; Neumann, Brent; Murphy, Kathleen; Silke, John; Gonda, Thomas J

    2008-01-01

    The Schlafen gene family has been implicated in lymphoid and myeloid maturation and differentiation as well as inflammation. However, little is known about the functions of this gene family except that anti-proliferative activities, particularly for Schlafen1, the prototype member of the family, have been reported. This was shown mainly by ectopic expression of Schlafen1 in murine fibroblasts resulting in growth inhibition and a G1 cell cycle arrest apparently via repression of Cyclin D1 expression. However, we have been unable to reproduce these findings. Schlafen1 and Schlafen2 failed to inhibit cell proliferation, cause G1 cell cycle arrest, or affect Cyclin D1 level in murine fibroblasts. This was regardless of whether overexpression was constitutive, induced or from transient transfections. Moreover, in our hands, Schlafen1 and -2 do not appear to regulate the activity of Cyclin D1 promoter. Importantly, we also showed that Schlafen1 and -2 do not play anti-proliferative roles in more physiologically-relevant myeloid cell lines. We therefore suggest that Schlafen1 and Schlafen2 might not have obligatory anti-proliferative activities, at least in vitro, and that efforts to explore their functions should be directed to other aspects, such as haemopoietic development and immune response.

  9. Graphene oxide inhibits malaria parasite invasion and delays parasitic growth in vitro.

    PubMed

    Kenry; Lim, Ying Bena; Nai, Mui Hoon; Cao, Jianshu; Loh, Kian Ping; Lim, Chwee Teck

    2017-09-28

    The interactions between graphene oxide (GO) and various biological entities have been actively investigated in recent years, resulting in numerous potential bioapplications of these nanomaterials. Despite this, the biological interactions between GO and disease-causing protozoan parasites have not been well elucidated and remain relatively unexplored. Here, we investigate the in vitro interactions between GO nanosheets and a particular species of malaria parasites, Plasmodium falciparum (P. falciparum). We hypothesize that GO nanosheets may exhibit antimalarial characteristic via action mechanisms of physical obstruction of P. falciparum parasites as well as nutrient depletion. To ascertain this, we characterize the physical interactions between GO nanosheets, red blood cells (RBCs), and malarial parasites as well as the adsorption of several biomolecules necessary for parasitic survival and growth on GO nanosheets. Subsequent to establishing the origin of this antimalarial behavior of GO nanosheets, their efficiency in inhibiting parasite invasion is evaluated. We observe that GO nanosheets at various tested concentrations significantly inhibit the invasion of malaria parasites into RBCs. Furthermore, GO nanosheets delay parasite progression from the ring to the trophozoite stage. Overall, this study may further shed light on the graphene-parasite interactions and potentially facilitate the development of nanomaterial-based strategies for combating malaria.

  10. Chitosan inhibits enterotoxigenic Clostridium perfringens type A in growth medium and chicken meat.

    PubMed

    Alnoman, Maryam; Udompijitkul, Pathima; Sarker, Mahfuzur R

    2017-06-01

    Clostridium perfringens is a spore-forming bacterium and a major cause of bacterial food-borne illness. In this study, we evaluated the inhibitory effects of chitosan against spore germination, spore outgrowth and vegetative growth of C. perfringens food poisoning (FP) isolates. Chitosan of differing molecular weights inhibited germination of spores of all tested FP isolates in a KCl germinant solution containing 0.1 mg/ml chitosan at pH 4.5. However, higher level (0.25 mg/ml) of chitosan was required to effectively arrest outgrowth of the germinated C. perfringens spores in Tripticase-yeast extract-glucose (TGY) medium. Furthermore, chitosan (1.0 mg/ml) was bacteriostatic against vegetative cells of C. perfringens in TGY medium. Although chitosan showed strong inhibitory activities against C. perfringens in laboratory medium, higher levels (2.0 mg/g) were required to achieve similar inhibition of spores inoculated into chicken meat. In summary, the inhibitory effects of chitosan against C. perfringens FP isolates was concentration dependent, and no major difference was observed when using different molecule weight chitosan as an inhibitor. Our results contribute to a better understanding on the potential application of chitosan in cooked meat products to control C. perfringens-associated disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Sulforaphane, a natural component of broccoli, inhibits vestibular schwannoma growth in vitro and in vivo

    PubMed Central

    Kim, Bo Gyung; Fujita, Takeshi; Stankovic, Konstantina M.; Welling, D. Bradley; Moon, In Seok; Choi, Jae Young; Yun, Jieun; Kang, Jong Soon; Lee, Jong Dae

    2016-01-01

    Vestibular schwannoma (VS) is an intracranial tumor that causes significant morbidity, including hearing loss, tinnitus, dizziness, and possibly even death from brainstem compression. However, FDA-approved pharmacologic treatments for VS do not exist. Sulforaphane (SFN) is a naturally occurring isothiocyanate found in cruciferous vegetables, such as broccoli, with potent chemoprotective effects in several cell types. Our objective was to determine whether SFN is effective against VS in vitro and in vivo. Human primary VS cells, HEI-193 schwannoma cells, and SC4 Nf2−/− Schwann cells were used to investigate the inhibitory effects of SFN in vitro. Cell proliferation was assessed by bromodeoxyuridine (BrdU) incorporation, and cell viability and metabolic activity was calculated by MTT assay. Apoptosis was measured by flow cytometry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and Western blot for cleaved caspases. A mouse model with a murine schwannoma allograft was also used to examine the antitumor activity of SFN. SFN exhibited significant antiproliferative activity in schwannoma cells in vitro, via the inhibition of HDAC activity and the activation of ERK. SFN treatment induced apoptosis and cell cycle arrest at the G2/M phase. SFN also significantly inhibited schwannoma growth in vivo. Our preclinical studies motivate a future prospective clinical study of SFN for the treatment of VS. PMID:27805058

  12. Macelignan inhibits bee pathogenic fungi Ascophaera apis growth through HOG1 pathway

    PubMed Central

    Shin, Y.K.; Kim, K.Y.

    2016-01-01

    Ascosphaera apis is a bee pathogen that causes bee larvae infection disease, to which treatment is not yet well investigated. The aim of this study was to investigate antifungal susceptibility in vitro against A. apis and to identify a new antifungal agent for this pathogen through minimal inhibitory concentration (MIC) assay and western blot analysis. Macelignan had 1.56 and 3.125 μg/mL MIC against A. apis after 24 and 48 h, respectively, exhibiting the strongest growth inhibition against A. apis among the tested compounds (corosolic acid, dehydrocostus lactone, loganic acid, tracheloside, fangchinoline and emodin-8-O-β-D-glucopyranoside). Furthermore, macelignan showed a narrow-ranged spectrum against various fungal strains without any mammalian cell cytotoxicity. In spite of miconazole having powerful broad-ranged anti-fungal activity including A. apis, it demonstrated strong cytotoxicity. Therefore, even if macelignan alone was effective as an antifungal agent to treat A. apis, combined treatment with miconazole was more useful to overcome toxicity, drug resistance occurrence and cost effectiveness. Finally, HOG1 was revealed as a target molecule of macelignan in the anti-A. apis activity by inhibiting phosphorylation using S. cerevisiae as a model system. Based on our results, macelignan, a food-grade antimicrobial compound, would be an effective antifungal agent against A. apis infection in bees. PMID:27383123

  13. Local acting Sticky-trap inhibits vascular endothelial growth factor dependent pathological angiogenesis in the eye

    PubMed Central

    Michael, Iacovos P; Westenskow, Peter D; Hacibekiroglu, Sabiha; Greenwald, Alissa Cohen; Ballios, Brian G; Kurihara, Toshihide; Li, Zhijie; Warren, Carmen M; Zhang, Puzheng; Aguilar, Edith; Donaldson, Laura; Marchetti, Valentina; Baba, Takeshi; Hussein, Samer M; Sung, Hoon-Ki; Iruela-Arispe, M Luisa; Rini, James M; van der Kooy, Derek; Friedlander, Martin; Nagy, Andras

    2014-01-01

    Current therapeutic antiangiogenic biologics used for the treatment of pathological ocular angiogenesis could have serious side effects due to their interference with normal blood vessel physiology. Here, we report the generation of novel antivascular endothelial growth factor-A (VEGF) biologics, termed VEGF “Sticky-traps,” with unique properties that allow for local inhibition of angiogenesis without detectable systemic side effects. Using genetic and pharmacological approaches, we demonstrated that Sticky-traps could locally inhibit angiogenesis to at least the same extent as the original VEGF-trap that also gains whole-body access. Sticky-traps did not cause systemic effects, as shown by uncompromised wound healing and normal tracheal vessel density. Moreover, if injected intravitreally, recombinant Sticky-trap remained localized to various regions of the eye, such as the inner-limiting membrane and ciliary body, for prolonged time periods, without gaining access either to the photoreceptors/choriocapillaris area or the circulation. These unique pharmacological characteristics of Sticky-trap could allow for safe treatment of pathological angiogenesis in patients with diabetic retinopathy and retinopathy of pre-maturity. PMID:24705878

  14. Sildenafil inhibits the growth of human colorectal cancer in vitro and in vivo

    PubMed Central

    Mei, Xiao-Long; Yang, Yang; Zhang, Yao-Jun; Li, Yong; Zhao, Jin-Ming; Qiu, Jian-Ge; Zhang, Wen-Ji; Jiang, Qi-Wei; Xue, You-Qiu; Zheng, Di-Wei; Chen, Yao; Qin, Wu-Ming; Wei, Meng-Ning; Shi, Zhi

    2015-01-01

    Colorectal cancer is the third most common human cancer with frequent overexpression of the cGMP-specific phosphodiesterase 5 (PDE5). In the present study, we investigated that the anticancer effect of sildenafil on human colorectal cancer in vitro and in vivo, which is a potent and selective inhibitor of PDE5 for the treatment of erectile dysfunction and pulmonary arterial hypertension in the clinic. Sildenafil significantly induced cell growth inhibition, cell cycle arrest and apoptosis of human colorectal cancer with increased intracellular reactive oxidative specie (ROS) levels, which were accompanied by obvious alterations of related proteins such as CDKs, Cyclins and PARP etc. Pretreatment with ROS scavenger N-acetyl-L-cysteine could reverse sildenafil-induced ROS accumulation and cell apoptosis. Inhibition of the activity of protein kinase G with KT-5823 could enhance sildenafil-induced apoptosis. Furthermore, sildenafil caused the reduction of xenograft models of human colorectal cancer in nude mice. Overall, these findings suggest that sildenafil has the potential to be used for treatment of human colorectal cancer. PMID:26807313

  15. Growth inhibition and apoptosis induced by 6-fluoro-3-formylchromone in hepatocellular carcinoma

    PubMed Central

    2014-01-01

    Background Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent cancers in human population. The 6-fluoro-3-formylchromone (FCC) has been shown to have anti-tumor activity against various tumor cells. However, the effects of FCC on HCC cell lines have not yet been reported. This study aims to research the effects of FCC on HCC and advance the understanding of the molecular mechanism. Methods HCC cell line SMMC-7721 was treated with FCC at various concentrations (0, 2, 5, 10, and 20 μg/ml) for 24, 48 and 72 h, respectively. The proliferations of SMMC-7721 cells were measured by MTT assays. After cultured 24 hours, cell cycle distribution and apoptosis were determined by flow cytometry. However, the expression levels of PCNA, Bax and Bcl-2 were measured by western blotting after 48 hours. Results FCC displayed a dose- and time-dependent inhibition of the SMMC-7721 cell proliferations in vitro. It also induced apoptosis with 45.4% and caused cell accumulation in G0/G1 phase with 21.5%. PCNA and Bcl-2 expression was significantly suppressed by FCC in a dose-dependent manner (P < 0.05), while Bax expression was increased. Conclusions FCC could significantly inhibit HCC cell growth in vitro through cell cycle arrest and inducing apoptosis by suppressing PCNA expression and modulating the Bax/Bcl-2 ratio. PMID:24708487

  16. Benzylidene acylhydrazides inhibit chlamydial growth in a type III secretion- and iron chelation-independent manner.

    PubMed

    Bao, Xiaofeng; Gylfe, Asa; Sturdevant, Gail L; Gong, Zheng; Xu, Shuang; Caldwell, Harlan D; Elofsson, Mikael; Fan, Huizhou

    2014-08-15

    Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection. However, these inhibitors also have the capacity to chelate iron, and it is possible that their antichlamydial effects are caused by iron starvation. Therefore, we have explored the modification of salicylidene acylhydrazides with the goal to uncouple the antichlamydial effect from iron starvation. We discovered that benzylidene acylhydrazides, which cannot chelate iron, inhibit chlamydial growth. Biochemical and genetic analyses suggest that the derivative compounds inhibit chlamydiae through a T3SS-independent mechanism. Four single nucleotide polymorphisms were identified in a Chlamydia muridarum variant resistant to benzylidene acylhydrazides, but it may be necessary to segregate the mutations to differentiate their roles in the resistance phenotype. Benzylidene acylhydrazides are well tolerated by host cells and probiotic vaginal Lactobacillus species and are therefore of potential therapeutic value. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  17. Influence of Polymers on the Crystal Growth Rate of Felodipine: Correlating Adsorbed Polymer Surface Coverage to Solution Crystal Growth Inhibition.

    PubMed

    Schram, Caitlin J; Taylor, Lynne S; Beaudoin, Stephen P

    2015-10-20

    The bioavailability of orally administered drugs that exhibit poor aqueous solubility can be enhanced with the use of supersaturating dosage forms. Stabilization of these forms by preventing or inhibiting crystallization in solution is an important area of study. Polymers can be used to stabilize supersaturated systems; however, the properties that impact their effectiveness as crystal growth rate inhibitors are not yet fully understood. In this study, the impact of various polymers on the crystal growth rate of felodipine and the conformation of these polymers adsorbed to crystalline felodipine was investigated in order to gain a mechanistic understanding of crystal growth inhibition. It was determined that polymer hydrophobicity impacted polymer adsorption as well as adsorbed polymer conformation. Polymer conformation impacts its surface coverage, which was shown to directly correlate to the polymer's effectiveness as a growth rate inhibitor. By modeling this correlation, it is possible to predict polymer effectiveness given the surface coverage of the polymer.

  18. A novel peptide sansalvamide analogue inhibits pancreatic cancer cell growth through G0/G1 cell-cycle arrest

    SciTech Connect

    Ujiki, Michael B. |; Milam, Ben; Ding Xianzhong |; Roginsky, Alexandra B.; Salabat, M. Reza; Talamonti, Mark S.; Bell, Richard H. |; Gu Wenxin; Silverman, Richard B. ||; Adrian, Thomas E. |. E-mail: tadrian@northwestern.edu

    2006-02-24

    Patients with pancreatic cancer have little hope for cure because no effective therapies are available. Sansalvamide A is a cyclic depsipeptide produced by a marine fungus. We investigated the effect of a novel sansalvamide A analogue on growth, cell-cycle phases, and induction of apoptosis in human pancreatic cancer cells in vitro. The sansalvamide analogue caused marked time- and concentration-dependent inhibition of DNA synthesis and cell proliferation of two human pancreatic cancer cell lines (AsPC-1 and S2-013). The analogue induced G0/G1 phase cell-cycle arrest and morphological changes suggesting induction of apoptosis. Apoptosis was confirmed by annexin V binding. This novel sansalvamide analogue inhibits growth of pancreatic cancer cells through G0/G1 arrest and induces apoptosis. Sansalvamide analogues may be valuable for the treatment of pancreatic cancer.

  19. Enhancement or inhibition of tumor growth by interferon: dependence on treatment protocol.

    PubMed

    Murasko, D M; Fresa, K; Mark, R

    1983-12-15

    MSC cells are tumor cells originally induced in BALB/c mice by Moloney sarcoma virus. In these studies we demonstrated that, although these tumor cells are sensitive in vitro both to lysis by NK or NK-like cells and to the growth-inhibitory effect of murine L-cell interferon (IFN), the growth of the tumor in vivo could be either inhibited or enhanced by IFN. The outcome of in vivo IFN treatment was dependent on the timing and route of IFN administration relative to tumor challenge. IFN given systematically at the same time as tumor challenge resulted in enhancement of primary tumor formation, rate of tumor growth and subsequent progressive tumor growth. In contrast, IFN administered at the site of tumor inoculation on days 1-3 after tumor challenge inhibited tumor formation and growth. Histopathology of tissue sections obtained from the site of tumor challenge confirmed these results. Similar studies performed in mice given 450 rads of X-irradiation showed that IFN could still inhibit tumor growth when administered at the site of tumor inoculation on days 1-3 after tumor challenge. IFN administered simultaneously with tumor challenge, however, did not enhance tumor growth in irradiated mice. These results are consistent with the interpretation that 1) inhibition of MSC-induced tumor growth by IFN has a radioresistant component and 2) the enhancement of MSC-induced tumor formation by IFN is dependent on interaction with a radiosensitive population of cells, possibly lymphoid cells.

  20. THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN

    EPA Science Inventory

    THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN.
    Harland and Liburdy (1) reported that 1.2-uT, 60-Hz magnetic fields could significantly block the inhibitory action of pharmacological levels of tamoxifen (10-7 M) on the growth of MCF-7 human br...

  1. THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN

    EPA Science Inventory

    THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN.
    Harland and Liburdy (1) reported that 1.2-uT, 60-Hz magnetic fields could significantly block the inhibitory action of pharmacological levels of tamoxifen (10-7 M) on the growth of MCF-7 human br...

  2. Bestatin inhibits cell growth, cell division, and spore cell differentiation in Dictyostelium discoideum.

    PubMed

    Poloz, Yekaterina; Catalano, Andrew; O'Day, Danton H

    2012-04-01

    Bestatin methyl ester (BME) is an inhibitor of Zn(2+)-binding aminopeptidases that inhibits cell proliferation and induces apoptosis in normal and cancer cells. We have used Dictyostelium as a model organism to study the effects of BME. Only two Zn(2+)-binding aminopeptidases have been identified in Dictyostelium to date, puromycin-sensitive aminopeptidase A and B (PsaA and PsaB). PSA from other organisms is known to regulate cell division and differentiation. Here we show that PsaA is differentially expressed throughout growth and development of Dictyostelium, and its expression is regulated by developmental morphogens. We present evidence that BME specifically interacts with PsaA and inhibits its aminopeptidase activity. Treatment of cells with BME inhibited the rate of cell growth and the frequency of cell division in growing cells and inhibited spore cell differentiation during late development. Overexpression of PsaA-GFP (where GFP is green fluorescent protein) also inhibited spore cell differentiation but did not affect growth. Using chimeras, we have identified that nuclear versus cytoplasmic localization of PsaA affects the choice between stalk or spore cell differentiation pathway. Cells that overexpressed PsaA-GFP (primarily nuclear) differentiated into stalk cells, while cells that overexpressed PsaAΔNLS2-GFP (cytoplasmic) differentiated into spores. In conclusion, we have identified that BME inhibits cell growth, division, and differentiation in Dictyostelium likely through inhibition of PsaA.

  3. Effects of methylmercury on primary cultured rat hepatocytes: Cell injury and inhibition of growth factor stimulated DNA synthesis

    SciTech Connect

    Tanno, Keiichi; Fukazawa, Toshiyuki; Tajima, Shizuko; Fujiki, Motoo )

    1992-08-01

    Many more studies deal with the toxicity of methylmercury on nervous tissue than on its toxicity to the liver. Methylmercury accumulates in the liver in higher concentrations than brain and the liver has the primary function of detoxifying methylmercury. According to recent studies, hepatocyte mitochondrial membranes are destroyed by methylmercury and DNA synthesis is inhibited by methylmercury during hepatocyte regeneration. Methylmercury alters the membrane ion permeability of isolate skate hepatocytes, and inhibits the metal-sensitive alcohol dehydrogenase and glutathione reductase of primary cultured rat hepatocytes. However, little is known about the effect of methylmercury on hepatocyte proliferation in primary cultured rat hepatocytes. We therefore used the primary cultured rat hepatocytes to investigate the effects of methylmercury on cell injury and growth factor stimulate DNA synthesis. The primary effect of methylmercury is to inhibit hepatocyte proliferation rather than to cause direct cell injury. 16 refs., 4 figs.

  4. Zafirlukast Inhibits Complexation of Lsr2 with DNA and Growth of Mycobacterium tuberculosis

    PubMed Central

    Pinault, Lucile; Han, Jeong-Sun; Kang, Choong-Min; Franco, Jimmy

    2013-01-01

    The mycobacterial nucleoid-associated protein Lsr2 is a DNA-bridging protein that plays a role in condensation and structural organization of the genome and acts as a global repressor of gene transcription. Here we describe experiments demonstrating that zafirlukast inhibits the complexation between Lsr2 and DNA in vitro. Zafirlukast is shown to inhibit growth in two different species of mycobacteria tested but exhibits no growth inhibition of Escherichia coli. The Lsr2 inhibitory activity is reflected in vivo as determined by monitoring of transcription levels in Mycobacterium tuberculosis. These data suggest that zafirlukast inhibits Lsr2 function in vivo, promoting dysregulation of the expression of an array of genes typically bound by Lsr2 and hindering growth. Since zafirlukast likely operates by a mechanism distinct from current M. tuberculosis drugs and is currently used as a prophylactic treatment for asthma, it offers an intriguing lead for development of new treatments for tuberculosis. PMID:23439641

  5. Inhibition of in Vitro Pollen Tube Growth by Isolated S-Glycoproteins of Nicotiana alata.

    PubMed Central

    Jahnen, W.; Lush, W. M.; Clarke, A. E.

    1989-01-01

    Pollen from three S-genotypes of Nicotiana alata was grown in vitro in the presence of S-glycoproteins isolated from styles of the same three genotypes. Pollen germination was not affected by the presence of the S-glycoproteins, but pollen tube growth of all genotypes was inhibited. S2 pollen was preferentially inhibited by the S2-glycoprotein and S3 pollen by the S3-glycoprotein. The S6-glycoprotein preferentially inhibited growth of both S2 and S6 pollen over S3 pollen. Heat treatment dramatically increased the inhibitory activity of the S-glycoproteins as inhibitors both of pollen germination and tube growth; after heat treatment, S-allele specificity of pollen tube inhibition was not detected. PMID:12359898

  6. Dietary fiber enhances TGF-β signaling and growth inhibition in the gut

    PubMed Central

    Cao, Yanna; Gao, Xuxia; Zhang, Weili; Zhang, Guohua; Nguyen, Anthony K.; Liu, Xianghua; Jimenez, Fernando; Cox, Charles S.; Townsend, Courtney M.

    2011-01-01

    Dietary fiber intake links to decreased risk of colorectal cancers. The underlying mechanisms remain unclear. Recently, we found that butyrate, a short-chain fatty acid produced in gut by bacterial fermentation of dietary fiber, enhances TGF-β signaling in rat intestinal epithelial cells (RIE-1). Furthermore, TGF-β represses inhibitors of differentiation (Ids), leading to apoptosis. We hypothesized that dietary fiber enhances TGF-β's growth inhibitory effects on gut epithelium via inhibition of Id2. In this study, Balb/c and DBA/2N mice were fed with a regular rodent chow or supplemented with a dietary fiber (20% pectin) and Smad3 level in gut epithelium was measured. In vitro, RIE-1 cells were treated with butyrate and TGF-β1, and cell functions were evaluated. Furthermore, the role of Ids in butyrate- and TGF-β-induced growth inhibition was investigated. We found that pectin feeding increased Smad3 protein levels in the jejunum (1.47 ± 0.26-fold, P = 0.045, in Balb/c mice; 1.49 ± 0.19-fold, P = 0.016, in DBA/2N mice), and phospho-Smad3 levels (1.92 ± 0.27-fold, P = 0.009, in Balb/c mice; 1.83 ± 0.28-fold, P = 0.022, in DBA/2N mice). Butyrate or TGF-β alone inhibited cell growth and induced cell cycle arrest. The combined treatment of butyrate and TGF-β synergistically induced cell cycle arrest and apoptosis in RIE-1 cells and repressed Id2 and Id3 levels. Furthermore, knockdown of Id2 gene expression by use of small interfering RNA caused cell cycle arrest and apoptosis. We conclude that dietary fiber pectin enhanced Smad3 expression and activation in the gut. Butyrate and TGF-β induced cell cycle arrest and apoptosis, which may be mediated by repression of Id2. Our results implicate a novel mechanism of dietary fiber in reducing the risk of colorectal cancer development. PMID:21454444

  7. Fifteen Days Microgravity Causes Growth in Calvaria of Mice

    PubMed Central

    Cory, Esther; Bhattacharya, Roshmi; Sah, Robert; Hargens, Alan R

    2014-01-01

    Bone remodeling may occur in spaceflight as a response to skeletal unloading and head-ward fluid shifts. While unloading causes significant loss of bone mass and density in legs of animals exposed to microgravity, increased blood and interstitial fluid flows accompanying microgravity-induced fluid redistribution may elicit an opposite effect in the head. Seven C57BL/6 mice were randomly chosen for exposure to 15 days of microgravity on the STS-131 mission, while eight littermates served as ground controls. Upon mission completion, all 15 mice calvariae were imaged on a micro-computed tomography scanner. A standardized rectangular volume was placed on the parietal bones of each calvaria for analyses, and three parameters were determined to measure increased parietal bone volume: bone volume (BV), cross-sectional thickness (CsTh), and tissue mineral density (TMD). Microgravity exposure caused a statistically significant increase in BV of the space flight (SF) group compared to the ground control (GC) group – the mean ± SD for SF group was 10.48 ± 0.47 %, compared to 9.64 ± 0.79 % for GC group (p<0.05). CsTh demonstrated a trend of increase from 0.099 ±0.006 mm in the GC group to 0.104 ±0.005 mm in the SF group (p=0.12). TMD was similar between the two groups with 0.878 ±0.029 g/cc for GC and 0.893 ± 0.028 g/cc for SF (p=0.31). Our results indicate that microgravity causes adaptive changes in calvarial bones that do not normally bear weight. These findings suggest that fluid shifts alone accompanying microgravity may initiate bone remodeling independent of skeletal loading by tissue. PMID:23791778

  8. Targeting PDK1 with dichloroacetophenone to inhibit acute myeloid leukemia (AML) cell growth.

    PubMed

    Qin, Lijun; Tian, Yun; Yu, Zhenlong; Shi, Dingbo; Wang, Jingshu; Zhang, Changlin; Peng, Ruoyu; Chen, Xuezhen; Liu, Congcong; Chen, Yiming; Huang, Wenlin; Deng, Wuguo

    2016-01-12

    Pyruvate dehydrogenase kinase-1 (PDK1), a key metabolic enzyme involved in aerobic glycolysis, is highly expressed in many solid tumors. Small molecule compound DAP (2,2-dichloroacetophenone) is a potent inhibitor of PDK1. Whether targeting PDK1 with DAP can inhibit acute myeloid leukemia (AML) and how it works remains unknown. In this study, we evaluated the effect of inhibition of PDK1 with DAP on cell growth, apoptosis and survival in AML cells and identified the underlying mechanisms. We found that treatment with DAP significantly inhibited cell proliferation, increased apoptosis induction and suppressed autophagy in AML cells in vitro, and inhibited tumor growth in an AML mouse model in vivo. We also showed that inhibition of PDK1 with DAP increased the cleavage of pro-apoptotic proteins (PARP and Caspase 3) and decreased the expression of the anti-apoptotic proteins (BCL-xL and BCL-2) and autophagy regulators (ULK1, Beclin-1 and Atg). In addition, we found that DAP inhibited the PI3K/Akt signaling pathway. Furthermore, we demonstrated that PDK1 interacted with ULK1, BCL-xL and E3 ligase CBL-b in AML cells, and DPA treatment could inhibit the interactions. Collectively, our results indicated that targeting PDK1 with DAP inhibited AML cell growth via multiple signaling pathways and suggest that targeting PDK1 may be a promising therapeutic strategy for AMLs.

  9. [Preliminary examination of a LB-H2O2 substance that inhibit Neisseria gonorrhea growth].

    PubMed

    Zheng, H; Cao, J; Jin, H; Wang, J

    1999-10-01

    To study the possible mechanism of H2O2-producing lactobacilli inhibited neisseria gonorrhoeae growth. H2O2-producing lactobacilli were coincubated with neisseria gonorrhoeae in vitro, LB+ cell were disrupted by sonication, the protein in the lactobacilli lysate was separated by filtration through different MW sizes membranes and was examined for the ability to inhibit N. gonorrhoeae catalase activity. When coincubation medium was at pH 5.0, there was a significant decrease in the gonococcal catalase activity, the lysates of LB+ also effectively inhibited gonococcal catalase activity. This inhibition was retained upon heating of lysate to 100 degrees C for 15 minutes but was lost with proteinase K treatment. The LB+ may inhibit growth of gonococci by production of catalase inhibitors.

  10. In vitro growth inhibition of mastitis pathogens by bovine teat skin normal flora.

    PubMed

    Woodward, W D; Besser, T E; Ward, A C; Corbeil, L B

    1987-01-01

    One factor contributing to differences in the susceptibility of cows to mastitis may be differences in the teat skin normal flora, which could inhibit or enhance the growth of pathogenic bacteria. Using in vitro cross-streaking methods, we found that 25% of the isolates of teat normal flora of non-lactating heifers inhibited the growth of selected mastitis pathogens, but enhancers were not detected. Gram-positive pathogens were inhibited to a greater extent than Gram-negative pathogens. Inhibition was not a characteristic of specific genera or species of normal flora, but rather a property of certain variants within a species. This phenomenon of inhibition of mastitis pathogens in vitro by normal flora may be useful as an in vivo biological control method to reduce the incidence of mastitis.

  11. Terpenoids inhibit Candida albicans growth by affecting membrane integrity and arrest of cell cycle.

    PubMed

    Zore, Gajanan B; Thakre, Archana D; Jadhav, Sitaram; Karuppayil, S Mohan

    2011-10-15

    Anti-Candida potential of six terpenoids were evaluated in this study against various isolates of Candida albicans (n=39) and non-C. albicans (n=9) that are differentially susceptible to fluconazole. All the six terpenoids tested, showed excellent activity and were equally effective against isolates of Candida sps., tested in this study. Linalool and citral were the most effective ones, inhibiting all the isolates at ≤0.064% (v/v). Five among the six terpenoids tested were fungicidal. Time dependent kill curve assay showed that MFCs of linalool and eugenol were highly toxic to C. albicans, killing 99.9% inoculum within seven min of exposure, while that of citronellal, linalyl acetate and citral required 15min, 1h and 2h, respectively. FIC index values (Linalool - 0.140, benzyl benzoate - 0.156, eugenol - 0.265, citral - 0.281 and 0.312 for linalyl acetate and citronellal) and isobologram obtained by checker board assay showed that all the six terpenoids tested exhibit excellent synergistic activity with fluconazole against a fluconazole resistant strain of C. albicans. Terpenoids tested arrested C. albicans cells at different phases of the cell cycle i.e. linalool and LA at G1, citral and citronellal at S phase and benzyl benzoate at G2-M phase and induced apoptosis. Linalool, citral, citronellal and benzyl benzoate caused more than 50% inhibition of germ tube induction at 0.008%, while eugenol and LA required 0.032 and 0.016% (v/v) concentrations, respectively. MICs of all the terpenoids for the C. albicans growth were non toxic to HeLa cells. Terpenoids tested exhibited excellent activity against C. albicans yeast and hyphal form growth at the concentrations that are non toxic to HeLa cells. Terpenoids tested in this study may find use in antifungal chemotherapy, not only as antifungal agents but also as synergistic agents along with conventional drugs like fluconazole.

  12. Inhibition of aquaporin-1 dependent angiogenesis impairs tumour growth in a mouse model of melanoma.

    PubMed

    Nicchia, Grazia P; Stigliano, Cinzia; Sparaneo, Angelo; Rossi, Andrea; Frigeri, Antonio; Svelto, Maria

    2013-05-01

    Prohibiting angiogenesis is an important therapeutic approach for fighting cancer and other angiogenic related diseases. Research focused on proteins that regulate abnormal angiogenesis has attracted intense interest in both academia and industry. Such proteins are able to target several angiogenic factors concurrently, thereby increasing the possibility of therapeutic success. Aquaporin-1 (AQP1) is a water channel membrane protein that promotes tumour angiogenesis by allowing faster endothelial cell migration. In this study we test the hypothesis that AQP1 inhibition impairs tumour growth in a mouse model of melanoma. After validating the inhibitor efficacy of two different AQP1 specific siRNAs in cell cultures, RNA interference experiments were performed by intratumoural injections of AQP1 siRNAs in mice. After 6 days of treatment, AQP1 siRNA treated tumours showed a 75 % reduction in volume when compared to controls. AQP1 protein level, in AQP1 knockdown tumours, was around 75 % that of the controls and was associated with a significant 40 % reduced expression of the endothelial marker, Factor VIII. Immunofluorescence analysis of AQP1 siRNA treated tumours showed a significantly lower microvessel density. Time course experiments demonstrated that repeated injections of AQP1 siRNA over time are effective in sustaining the inhibition of tumour growth. Finally, we have confirmed the role of AQP1 in sustaining an active endothelium during angiogenesis and we have shown that AQP1 reduction causes an increase in VEGF levels. In conclusion, this study validates AQP1 as a pro-angiogenic protein, relevant for the therapy of cancer and other angiogenic-related diseases such as psoriasis, endometriosis, arthritis and atherosclerosis.

  13. The lactic acid bacteria metabolite phenyllactic acid inhibits both radial growth and sporulation of filamentous fungi

    PubMed Central

    2013-01-01

    Background Food spoilage caused by molds is a severe problem. In food and feed, e.g. dairy products, sourdough bread and silage, lactic acid bacteria are used as starter cultures. Besides lactic and acetic acid, some strains produce other low molecular weight compounds with antifungal activities. One of these metabolites is phenyllactic acid (PLA), well known for its antifungal effect. The inhibitory effect of PLA has only partially been investigated, and the objective of this study was to elucidate in detail the antifungal properties of PLA. Results We investigated the outgrowth of individual conidia from Aspergillus niger, Cladosporium cladosporioides and Penicillium roqueforti, and observed the morphologies of resulting colonies on solid media using different acid concentrations. We found that PLA inhibits molds similar to weak acid preservatives. Furthermore, it has an additional activity: at sub-inhibitory concentrations, fungal colonies displayed slower radial growth and inhibited sporulation. The L isoform of PLA is a more potent inhibitor than the D form. Increased expression of phiA was observed during PLA treatment. This gene was initially identified as being induced by Streptomyces-produced macrolide antibiotics, and is shown to be a structural protein in developed cells. This suggests that PhiA may act as a general stress protectant in fungi. Conclusion From a food protection perspective, the results of this study support the usage of lactic acid bacteria strains synthesizing PLA as starter cultures in food and feed. Such starter cultures could inhibit spore synthesis, which would be beneficial as many food borne fungi are spread by airborne spores. PMID:24229396

  14. The lactic acid bacteria metabolite phenyllactic acid inhibits both radial growth and sporulation of filamentous fungi.

    PubMed

    Svanström, Åsa; Boveri, Silvio; Boström, Emma; Melin, Petter

    2013-11-14

    Food spoilage caused by molds is a severe problem. In food and feed, e.g. dairy products, sourdough bread and silage, lactic acid bacteria are used as starter cultures. Besides lactic and acetic acid, some strains produce other low molecular weight compounds with antifungal activities. One of these metabolites is phenyllactic acid (PLA), well known for its antifungal effect. The inhibitory effect of PLA has only partially been investigated, and the objective of this study was to elucidate in detail the antifungal properties of PLA. We investigated the outgrowth of individual conidia from Aspergillus niger, Cladosporium cladosporioides and Penicillium roqueforti, and observed the morphologies of resulting colonies on solid media using different acid concentrations. We found that PLA inhibits molds similar to weak acid preservatives. Furthermore, it has an additional activity: at sub-inhibitory concentrations, fungal colonies displayed slower radial growth and inhibited sporulation. The L isoform of PLA is a more potent inhibitor than the D form. Increased expression of phiA was observed during PLA treatment. This gene was initially identified as being induced by Streptomyces-produced macrolide antibiotics, and is shown to be a structural protein in developed cells. This suggests that PhiA may act as a general stress protectant in fungi. From a food protection perspective, the results of this study support the usage of lactic acid bacteria strains synthesizing PLA as starter cultures in food and feed. Such starter cultures could inhibit spore synthesis, which would be beneficial as many food borne fungi are spread by airborne spores.

  15. Interleukin 2 inhibits in vitro growth of human T cell lines carrying retrovirus.

    PubMed

    Sugamura, K; Nakai, S; Fujii, M; Hinuma, Y

    1985-05-01

    Four human T cell lines, TL-Mor, TL-Su, TL-TerI, and TL-OmI, carrying human T cell leukemia virus (HTLV), were established previously. TL-Mor, TL-Su, and TL-TerI were derived from interleukin 2 (IL-2)-dependent parental cell lines cloned from peripheral blood leukocytes (PBL) of three healthy HTLV carriers, while TL-OmI was directly established from PBL of a patient with adult T cell leukemia. These four TL cell lines grow autonomously without IL-2. When they were cultured in the presence of IL-2, their growth was inhibited after a few days. This growth inhibition depended on the dose of IL-2, and the effective dose significantly promoted growth of their parental IL-2-dependent cell lines. The growth inhibition is demonstrated to be due to specific binding of IL-2 to receptors on the TL cells.

  16. Stachytarpheta cayennensis extract inhibits promastigote and amastigote growth in Leishmania amazonensis via parasite arginase inhibition.

    PubMed

    Maquiaveli, Claudia do Carmo; Oliveira E Sá, Amanda Maria; Vieira, Paulo Cezar; da Silva, Edson Roberto

    2016-11-04

    Stachytarpheta cayennensis is a plant that is traditionally used to treat tegumentary leishmaniasis and as an anti-inflammatory agent. This study aimed to evaluate the action of S. cayennensis extracts on the Leishmania (Leishmania) amazonensis arginase enzyme. S. cayennensis was collected from the Brazilian Amazon region. Aqueous extracts were fractionated with n-butanol. The leishmanicidal effects of the n-butanolic fraction (BUF) were evaluated in L. (L.) amazonensis promastigotes and amastigotes. BUF was tested against recombinant arginase from both L. (L.) amazonensis and macrophage arginase. Promastigote cultures and infected macrophage cultures were supplemented with L-ornithine to verify arginase inhibition. NMR analysis was used to identify the major components of BUF. BUF showed an EC50 of 51 and 32µg/mL against promastigotes and amastigotes of L. (L.) amazonensis, respectively. BUF contains a mixture of verbascoside and isoverbascoside (7:3 ratio) and is a potent L. (L.) amazonensis arginase inhibitor (IC50=1.2µg/mL), while macrophage arginase was weakly inhibited (IC50>1000µg/mL). The inhibition of arginase by BUF in promastigotes and amastigotes could be demonstrated by culture media supplementation with L-ornithine, a product of the hydrolysis of L-arginine by arginase. Leishmanicidal effects of the S. cayennensis BUF fraction on L. (L.) amazonensis are associated with selective parasite arginase inhibition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Lipoteichoic acid synthesis inhibition in combination with antibiotics abrogates growth of multidrug-resistant Enterococcus faecium.

    PubMed

    Paganelli, Fernanda L; van de Kamer, Tim; Brouwer, Ellen C; Leavis, Helen L; Woodford, Neil; Bonten, Marc J M; Willems, Rob J L; Hendrickx, Antoni P A

    2017-03-01

    Enterococcus faecium is a multidrug-resistant (MDR) nosocomial pathogen causing significant morbidity in debilitated patients. New antimicrobials are needed to treat antibiotic-resistant E. faecium infections in hospitalised patients. E. faecium incorporates lipoteichoic acid (LTA) (1,3-polyglycerol-phosphate linked to glycolipid) in its cell wall. The small-molecule inhibitor 1771 [2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate] specifically blocks the activity of Staphylococcus aureus LtaS synthase, which polymerises 1,3-glycerolphosphate into LTA polymers. Here we characterised the effects of the small-molecule inhibitor 1771 on the growth of E. faecium isolates, alone (28 strains) or in combination with the antibiotics vancomycin, daptomycin, ampicillin, gentamicin or linezolid (15 strains), and on biofilm formation (16 strains). Inhibition of LTA synthesis at the surface of the cell by compound 1771 in combination with current antibiotic therapy abrogates enterococcal growth in vitro but does not affect mature E. faecium biofilms. Targeting LTA synthesis may provide new possibilities to treat MDR E. faecium infections.

  18. Growth inhibition and effect on photosystem by three imidazolium chloride ionic liquids in rice seedlings.

    PubMed

    Liu, Huijun; Zhang, Shuxian; Zhang, Xiaoqiang; Chen, Caidong

    2015-04-09

    The effects of three imidazolium chloride ionic liquids (ILs) including 1-octyl-3-methylimidazolium chloride ionic liquid ([OMIM]Cl), 1-decyl-3-methylimidazolium chloride ionic liquid ([DMIM]Cl) and 1-dodecyl-3-methylimidazolium chloride ionic liquid ([C12MIM]Cl) were studied in hydroponically grown rice seedlings. The growth inhibition rate increased and the Hill reaction activity of isolated rice chloroplasts decreased with increasing ILs concentrations. The IC50,5d for stem length was 0.70 mg/L of [OMIM]Cl, 0.15 mg/L of [DMIM]Cl, and 0.055 mg/L of [C12MIM]Cl, respectively. The SOD, POD and CAT activities of chloroplast exhibited initial increases followed by decreases in activity with increasing ILs concentrations. Chlorophyll fluorescence parameters such as the maximum effective quantum yield of PSII(Fv/Fm), the potential activity of PSII(Fv/F0), the yield of photochemical quantum [Y(II)], the photochemical quenching coefficient (qP), the non-photochemical quenching coefficient (NPQ) and the relative electron transport ratio (rETR) were affected, showing that ILs will damage the PSII. The results demonstrated that imidazolium chloride ILs are phytotoxic to rice growth and their photosystem, the toxicity increased as the alkyl chain length increased with the following order: [OMIM]Cl<[DMIM]Cl<[C12MIM]Cl. The results will help to better understand the possible role of the defense mechanism in rice caused by ILs exposure.

  19. Spartin Regulates Synaptic Growth and Neuronal Survival by Inhibiting BMP-Mediated Microtubule Stabilization

    PubMed Central

    Nahm, Minyeop; Lee, Min-Jung; Parkinson, William; Lee, Mihye; Kim, Haeran; Kim, Yoon-Jung; Kim, Sungdae; Cho, Yi Sul; Min, Byung-Moo; Bae, Yong Chul; Broadie, Kendal; Lee, Seungbok

    2013-01-01

    SUMMARY Troyer syndrome is a hereditary spastic paraplegia caused by human spartin (SPG20) gene mutations. We have generated a Drosophila disease model showing that Spartin functions presynaptically with endocytic adaptor Eps15 to regulate synaptic growth and function. Spartin inhibits bone morphogenetic protein (BMP) signaling by promoting endocytic degradation of BMP receptor wishful thinking (Wit). Drosophila fragile X mental retardation protein (dFMRP) and Futsch/MAP1B are downstream effectors of Spartin and BMP signaling in regulating microtubule stability and synaptic growth. Loss of Spartin or elevation of BMP signaling induces age-dependent progressive defects resembling hereditary spastic paraplegias, including motor dysfunction and brain neurodegeneration. Null spartin phenotypes are prevented by administration of the microtubule-destabilizing drug vinblastine. Together, these results demonstrate that Spartin regulates both synaptic development and neuronal survival by controlling microtubule stability via the BMP-dFMRP-Futsch pathway, suggesting that impaired regulation of microtubule stability is a core pathogenic component in Troyer syndrome. PMID:23439121

  20. Spartin regulates synaptic growth and neuronal survival by inhibiting BMP-mediated microtubule stabilization.

    PubMed

    Nahm, Minyeop; Lee, Min-Jung; Parkinson, William; Lee, Mihye; Kim, Haeran; Kim, Yoon-Jung; Kim, Sungdae; Cho, Yi Sul; Min, Byung-Moo; Bae, Yong Chul; Broadie, Kendal; Lee, Seungbok

    2013-02-20

    Troyer syndrome is a hereditary spastic paraplegia caused by human spartin (SPG20) gene mutations. We have generated a Drosophila disease model showing that Spartin functions presynaptically with endocytic adaptor Eps15 to regulate synaptic growth and function. Spartin inhibits bone morphogenetic protein (BMP) signaling by promoting endocytic degradation of BMP receptor wishful thinking (Wit). Drosophila fragile X mental retardation protein (dFMRP) and Futsch/MAP1B are downstream effectors of Spartin and BMP signaling in regulating microtubule stability and synaptic growth. Loss of Spartin or elevation of BMP signaling induces age-dependent progressive defects resembling hereditary spastic paraplegias, including motor dysfunction and brain neurodegeneration. Null spartin phenotypes are prevented by administration of the microtubule-destabilizing drug vinblastine. Together, these results demonstrate that Spartin regulates both synaptic development and neuronal survival by controlling microtubule stability via the BMP-dFMRP-Futsch pathway, suggesting that impaired regulation of microtubule stability is a core pathogenic component in Troyer syndrome.

  1. Depleting tumor-NQO1 Potentiates Anoikis and Inhibits Growth of NSCLC

    PubMed Central

    Chakrabarti, Gaurab; Boothman, David A.; Bey, Erik A.

    2015-01-01

    The fundamental role that NAD(P)H/quinone oxidoreductase 1 (NQO1) plays, in normal cells, as a cyto-protective enzyme guarding against stress induced by reactive oxygen species (ROS) is well documented. However, what is not known is whether the observed overexpression of NQO1 in neoplastic cells contributes to their survival. The current study discovered that depleting NQO1 expression in A549 and H292 lung adenocarcinoma cells caused an increase in ROS formation, inhibited anchorage-independent growth, increased anoikis sensitization and decreased 3-D tumor-spheroid invasion. These in vivo data further implicate tumor-NQO1 expression in a pro-tumor survival role, since its depletion suppressed cell proliferation and decreased lung tumor xenograft growth. Finally, these data reveal an exploitable link between tumor-NQO1 expression and the survival of lung tumors since NQO1 depletion significantly decreased the percentage of ALDH(high) cancer cells within the tumor population. PMID:26553038

  2. Excitation, inhibition, local oscillations, or large-scale loops: what causes the symptoms of schizophrenia?

    PubMed Central

    Lisman, John

    2011-01-01

    What causes the positive, negative, and cognitive symptoms of schizophrenia? The importance of circuits is underscored by the finding that no single gene contributes strongly to the disease. Thus, some circuit abnormality to which many proteins can contribute is the likely cause. There are several major hypotheses regarding the circuitry involved: 1) a change in the balance of excitation/inhibition in the PFC; 2) abnormal EEG oscillations in the gamma range; 3) an increase in theta/delta EEG power related to changes in the thalamus (particularly midline nuclei); 4) hyperactivity in the hippocampus and consequent dopamine hyperfunction; or 5) deficits in corollary discharge. Evidence for these hypotheses will be reviewed. PMID:22079494

  3. Excitation, inhibition, local oscillations, or large-scale loops: what causes the symptoms of schizophrenia?

    PubMed

    Lisman, John

    2012-06-01

    What causes the positive, negative, and cognitive symptoms of schizophrenia? The importance of circuits is underscored by the finding that no single gene contributes strongly to the disease. Thus, some circuit abnormality to which many proteins can contribute is the likely cause. There are several major hypotheses regarding the circuitry involved: first, a change in the balance of excitation/inhibition in the prefrontal cortex (PFC); second, abnormal EEG oscillations in the gamma range; third, an increase in theta/delta EEG power related to changes in the thalamus (particularly midline nuclei); fourth, hyperactivity in the hippocampus and consequent dopamine hyperfunction; and fifth, deficits in corollary discharge. Evidence for these hypotheses will be reviewed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Dimethylthiourea inhibits heart weight and hematocrit changes caused by dietary copper deficiency

    SciTech Connect

    Saari, J.T. )

    1991-03-11

    Feeding antioxidants to rats in a copper (Cu)-deficient diet can partially inhibit the cardiac enlargement and anemia caused by Cu deficiency. This study was done to determine whether an antioxidant which bypassed the gastrointestinal tract was also protective and whether an agent more potent than previously used was more effective in this inhibition. Male, weanling rats were fed diets deficient or sufficient in Cu for 4 wks. Dimethylthiourea (DMTU) or saline was injected (ip) 4 times a week; minimum amount of DMTU retained during the experiment was estimated to be 250 mg/kg. Unlike other antioxidants, DMTU completely prevented the increase in heart wt/body wt ratio; like the other agents, it only partially inhibited the anemia of Cu deficiency. DMTU did not affect plasma or liver Cu content of CuD rats; however, heart copper of CuD rats was significantly increased by DMTU. The effects of DMTU on heart size and hematocrit (Hct) may be attributed to its antioxidant function, but the possibility of altered mineral status must also be considered.

  5. Ruxolitinib found to cause eyelash growth: a case report.

    PubMed

    Song, Julia; Song, Alice; Palmares, Trisa; Song, Michael; Song, Harold

    2017-07-12

    Hypereosinophilic syndrome is a hematologic disorder in which the eosinophils proliferate. Oral Janus kinase inhibitors are known to be effective treating hypereosinophilic syndrome. Janus kinase inhibitors have also demonstrated efficacy in alopecia. Madarosis is a condition in which the eyelashes are missing or absent and can been seen in alopecia patients. We present the case of a 77-year-old Asian man who was diagnosed with hypereosinophilic syndrome, refractive to all medications except ruxolitinib. He responded well. It was noted unexpectedly that his eyelashes grew much longer than they were normally. Previous studies have demonstrated an improvement in alopecia areata, with increased hair growth on the head and eyebrows. This study demonstrates that longer eyelashes may be another effect of oral Janus kinase inhibitors. We report the first case of eyelash elongation and thickening in a patient taking ruxolitinib. Physicians and patients should be aware of the side effect of these Janus kinase inhibitors. Further investigation is needed to ascertain whether ruxolitinib or other interleukin inhibitors can aid in the treatment of madarosis.

  6. Inhibition of telomerase activity by dominant-negative hTERT retards the growth of breast cancer cells.

    PubMed

    Rao, Yaojian; Xiong, Wei; Liu, Huijuan; Jia, Chunxia; Zhang, Hongxing; Cui, Zesheng; Zhang, Ya; Cui, Jiawei

    2016-03-01

    Telomerase, a ribonucleoprotein enzyme mainly consisted of a catalytic protein subunit human telomerase reverse transcriptase (hTERT) and a human telomerase RNA component, is responsible for maintaining telomeres. Telomerase over-expression correlates significantly with tumors and is a prognostic marker. However, telomerase over-expression in breast cancers and the effect of telomerase inhibition as a candidate cancer therapy are unknown. We used the dominant-negative mutant of hTERT (DN-hTERT) to inhibit telomerase activity on human breast adenocarcinoma cell line MCF-7 by transfection. Telomeric repeat amplification protocol assays and real-time quantitative RT-PCR were performed to investigate telomerase activity as well as expression of hTERT. Telomere length was measured by the flow-fluorescence in situ hybridization assay. Cell proliferation was assessed by the WST-8 assay, and apoptosis was evaluated by flow cytometry. The tumor formation ability of MCF-7 cells was investigated by transplanting cells subcutaneously into BALB/c nude mice. Ectopic expression of DN-hTERT caused dramatically inhibition of telomerase activity and reduction of telomere length. Telomerase inhibition induced growth arrest and apoptosis of MCF7 cells in vitro and loss of tumorigenic properties in vivo. This study shows that telomerase inhibition by DN-hTERT can effectively inhibit the cell viability and tumorigenicity of MCF7 cells and is an attractive approach for breast cancer therapy.

  7. Inhibition of intracellular growth of Listeria monocytogenes by antibiotics.

    PubMed Central

    Michelet, C; Avril, J L; Cartier, F; Berche, P

    1994-01-01

    We studied the activities of 15 antibiotics on the intracellular growth of Listeria monocytogenes in a HeLa cell line. After 24 h of contact with the infected cells, the antibiotics most effective against the intracellular growth of the 10 strains tested were amoxicillin, temafloxacin, and sparfloxacin, which nevertheless failed to totally eliminate the intracellular bacteria. Rifampin and co-trimoxazole had variable effects, depending on the isolates studied. The most active combinations were amoxicillin-sparfloxacin, co-trimoxazole-gentamicin, and sparfloxacin-co-trimoxazole. The results suggest the value of using a cell culture technique to study the activities of antibiotics against certain bacteria with intracellular sites of multiplication. PMID:8203836

  8. Jasmonic Acid Enhances Al-Induced Root Growth Inhibition1[OPEN

    PubMed Central

    Yang, Zhong-Bao; Ma, Yanqi

    2017-01-01

    Phytohormones such as ethylene and auxin are involved in the regulation of the aluminum (Al)-induced root growth inhibition. Although jasmonate (JA) has been reported to play a crucial role in the regulation of root growth and development in response to environmental stresses through interplay with ethylene and auxin, its role in the regulation of root growth response to Al stress is not yet known. In an attempt to elucidate the role of JA, we found that exogenous application of JA enhanced the Al-induced root growth inhibition. Furthermore, phenotype analysis with mutants defective in either JA biosynthesis or signaling suggests that JA is involved in the regulation of Al-induced root growth inhibition. The expression of the JA receptor CORONATINE INSENSITIVE1 (COI1) and the key JA signaling regulator MYC2 was up-regulated in response to Al stress in the root tips. This process together with COI1-mediated Al-induced root growth inhibition under Al stress was controlled by ethylene but not auxin. Transcriptomic analysis revealed that many responsive genes under Al stress were regulated by JA signaling. The differential responsive of microtubule organization-related genes between the wild-type and coi1-2 mutant is consistent with the changed depolymerization of cortical microtubules in coi1 under Al stress. In addition, ALMT-mediated malate exudation and thus Al exclusion from roots in response to Al stress was also regulated by COI1-mediated JA signaling. Together, this study suggests that root growth inhibition is regulated by COI1-mediated JA signaling independent from auxin signaling and provides novel insights into the phytohormone-mediated root growth inhibition in response to Al stress. PMID:27932419

  9. Leaf Litter Inhibits Growth of an Amphibian Fungal Pathogen.

    PubMed

    Stoler, Aaron B; Berven, Keith A; Raffel, Thomas R

    2016-06-01

    Past studies have found a heterogeneous distribution of the amphibian chytrid fungal pathogen, Batrachochytrium dendrobatidis (Bd). Recent studies have accounted for some of this heterogeneity through a positive association between canopy cover and Bd abundance, which is attributed to the cooling effect of canopy cover. We questioned whether leaf litter inputs that are also associated with canopy cover might also alter Bd growth. Leaf litter inputs exhibit tremendous interspecific chemical variation, and we hypothesized that Bd growth varies with leachate chemistry. We also hypothesized that Bd uses leaf litter as a growth substrate. To test these hypotheses, we conducted laboratory trials in which we exposed cultures of Bd to leachate of 12 temperate leaf litter species at varying dilutions. Using a subset of those 12 litter species, we also exposed Bd to pre-leached litter substrate. We found that exposure to litter leachate and substrate reduced Bd spore and sporangia densities, although there was substantial variation among treatments. In particular, Bd densities were inversely correlated with concentrations of phenolic acids. We conducted a field survey of phenolic concentrations in natural wetlands which verified that the leachate concentrations in our lab study are ecologically relevant. Our study reinforces prior indications that positive associations between canopy cover and Bd abundance are likely mediated by water temperature effects, but this phenomenon might be counteracted by changes in aquatic chemistry from leaf litter inputs.

  10. Transcription factor LSF (TFCP2) inhibits melanoma growth

    PubMed Central

    Goto, Yuji; Yajima, Ichiro; Kumasaka, Mayuko; Ohgami, Nobutaka; Tanaka, Asami; Tsuzuki, Toyonori; Inoue, Yuji; Fukushima, Satoshi; Ihn, Hironobu; Kyoya, Mikiko; Ohashi, Hiroyuki; Kawakami, Tamihiro; Bennett, Dorothy C.; Kato, Masashi

    2016-01-01

    Late SV40 factor 3 (LSF), a transcription factor, contributes to human hepatocellular carcinoma (HCC). However, decreased expression level of LSF in skin melanoma compared to that in benign melanocytic tumors and nevi in mice and humans was found in this study. Anchorage-dependent and -independent growth of melanoma cells was suppressed by LSF overexpression through an increased percentage of G1 phase cells and an increased p21CIP1 expression level in vitro and in vivo. Anchorage-dependent growth in LSF-overexpressed melanoma cells was promoted by depletion of LSF in the LSF-overexpressed cells. Integrated results of our EMSA and chromatin immunoprecipitation assays showed binding of LSF within a 150-bp upstream region of the transcription start site of p21CIP1 in melanoma cells. Taken together, our results suggest potential roles of LSF as a growth regulator through control of the transcription of p21CIP1 in melanocytes and melanoma cells as well as a biomarker for nevus. PMID:26506241

  11. TGF beta-induced growth inhibition in primary fibroblasts requires the retinoblastoma protein.

    PubMed

    Herrera, R E; Mäkelä, T P; Weinberg, R A

    1996-09-01

    Transforming growth factor beta (TGF beta) inhibits cell proliferation by inducing a G1 cell-cycle arrest. Cyclin/CDK complexes have been implicated in this arrest, because TGF beta treatment leads to inhibition of cyclin/CDK activity. We have investigated the role of the retinoblastoma protein (pRb) in TGF beta-induced growth arrest by using RB+/+ and RB-/- primary mouse embryo fibroblasts. In both of these cell types, TGF beta inhibits CDK4-associated kinase activity. However, whereas CDK2-associated kinase activity was completely inhibited by TGF beta in the wild-type cells, it was reduced only slightly in the RB mutant cells. In addition, at high-cell density the growth-inhibitory effects of TGF beta are no longer observed in the RB-/- cells; on the contrary, TGF beta treatment promotes the growth of these mutant fibroblasts. Thus, under certain cellular growth conditions, elimination of pRb transforms the growth-inhibitory effects of TGF beta into growth-stimulatory effects. These observations could help to explain why TGF beta is often found to enhance tumorigenicity in vivo and why inactivation of the RB gene leads to tumorigenesis.

  12. Inhibition of ice crystal growth in ice cream mix by gelatin hydrolysate.

    PubMed

    Damodaran, Srinivasan

    2007-12-26

    The inhibition of ice crystal growth in ice cream mix by gelatin hydrolysate produced by papain action was studied. The ice crystal growth was monitored by thermal cycling between -14 and -12 degrees C at a rate of one cycle per 3 min. It is shown that the hydrolysate fraction containing peptides in the molecular weight range of about 2000-5000 Da exhibited the highest inhibitory activity on ice crystal growth in ice cream mix, whereas fractions containing peptides greater than 7000 Da did not inhibit ice crystal growth. The size distribution of gelatin peptides formed in the hydrolysate was influenced by the pH of hydrolysis. The optimum hydrolysis conditions for producing peptides with maximum ice crystal growth inhibitory activity was pH 7 at 37 degrees C for 10 min at a papain to gelatin ratio of 1:100. However, this may depend on the type and source of gelatin. The possible mechanism of ice crystal growth inhibition by peptides from gelatin is discussed. Molecular modeling of model gelatin peptides revealed that they form an oxygen triad plane at the C-terminus with oxygen-oxygen distances similar to those found in ice nuclei. Binding of this oxygen triad plane to the prism face of ice nuclei via hydrogen bonding appears to be the mechanism by which gelatin hydrolysate might be inhibiting ice crystal growth in ice cream mix.

  13. Lentivirus-mediated RNAi knockdown of insulin-like growth factor-1 receptor inhibits the growth and invasion of hepatocellular carcinoma via down-regulating midkine expression

    PubMed Central

    Huang, Qiu Yan; Tang, Hui Jun; Wang, Min; Cao, Guo Li; Yi, Ting Zhuang; Wu, Sheng Lan; Xu, Wei Jie; Tang, Shao Hui

    2016-01-01

    The insulin-like growth factor-1 receptor (IGF-1R) overexpression contributes to the development of a variety of cancers. The present study explored the role of IGF-1R in the development and progression of hepatocellular carcinoma (HCC) and the possibility of IGF-1R silencing by lentivirus-mediated RNA interference (RNAi) as a therapeutic target for HCC. We showed that IGF-1R mRNA was up-regulated in Huh7 and Hep3B cells and human HCC tissues, and that IGF-1R knockdown by RNAi led to decreased proliferation, apoptosis induction, and decreased migration and invasion of Huh7 and Hep3B cells. Further, the in vivo study indicated that IGF-1R knockdown markedly diminished the tumorigenesis and metastasis of Huh7 xenograft. Moreover, the intratumoral administration of lentivirus-IGF-1R siRNA led to significant tumor growth inhibition in an established Huh7 xenograft model. Mechanistic investigations showed that midkine was found to be the most significantly down-regulated protein in Huh7 cells with IGF-1R knockdown, and ectopic overexpression of midkine significantly rescued inhibition of Huh7 cell proliferation, migration, and invasion caused by IGF-1R suppression. Collectively, these data suggest that IGF-1R inhibition by RNAi can significantly suppress HCC growth and invasion at least partially through down-regulating midkine expression, and IGF-1R is a potential target for HCC gene therapy. PMID:27813495

  14. Genetic knockout and pharmacologic inhibition of NCX2 cause natriuresis and hypercalciuria.

    PubMed

    Gotoh, Yusuke; Kita, Satomi; Fujii, Makoto; Tagashira, Hideaki; Horie, Ichiro; Arai, Yuji; Uchida, Shinichi; Iwamoto, Takahiro

    2015-01-09

    The Na(+)/Ca(2+) exchanger (NCX) is a bidirectional transporter that is controlled by membrane potential and transmembrane gradients of Na(+) and Ca(2+). Although two isoforms of NCX1 and NCX2 are coexpressed on the basolateral membrane of the distal nephron, the functional significance of these isoforms is not entirely clear. Therefore, we used NCX1- and NCX2-heterozygote knockout mice (KO) and their double KO, as well as isoform-selective NCX inhibitors, to determine the roles of NCX isoforms in urine formation and electrolyte excretion in mice. NCX inhibitors, particularly NCX2-sensitive inhibitors, caused a dose-dependent natriuresis and in a higher dose, moreover, hypercalciuria. Consistently, NCX1-KO possessed normal renal function similar to wild-type mice (WT), whereas NCX2-KO and double KO exhibited moderate natriuresis and hypercalciuria. Notably, renal responses to YM-244769 were equivalently observed in NCX1-KO and WT, but disappeared in NCX2-KO and double KO. Thus, functional inhibition of NCX2 initially causes natriuresis, and further inhibition of NCX2 produces hypercalciuria, suggesting that the functional significance of NCX2 lies in Na(+) and Ca(2+) reabsorption of the kidney.

  15. Molecular cloning of genetic determinants for inhibition of fungal growth by a fluorescent pseudomonad.

    PubMed Central

    Gutterson, N I; Layton, T J; Ziegle, J S; Warren, G J

    1986-01-01

    Pseudomonas fluorescens HV37a inhibits growth of the fungus Pythium ultimum in vitro. Optimal inhibition is observed on potato dextrose agar, a rich medium. Mutations eliminating fungal inhibition were obtained after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Mutants were classified by cosynthesis and three groups were distinguished, indicating that a minimum of three genes are required for fungal inhibition. Cosmids that contain wild-type alleles of the genes were identified in an HV37a genomic library by complementation of the respective mutants. This analysis indicated that three distinct genomic regions were required for fungal inhibition. The cosmids containing these loci were mapped by transposon insertion mutagenesis. Two of the cosmids were found to contain at least two genes each. Therefore, at least five genes in HV37a function as determinants of fungal inhibition. Images PMID:3005234

  16. [The causes of the biological action of electrochemically activated solutions by changes in the growth of Escherichia coli cells].

    PubMed

    Miroshnikov, A I

    2004-01-01

    To study the causes of the biological effect of electrochemically activated solutions, nutrient growth media M 9 were prepared using catholyte and anolyte solutions containing separate components of the nutrient medium, such as distilled water, phosphate buffer, phosphate buffer with chlorides (NaCl, NH4Cl), and chlorides. The biological activity of different nutrient media was assessed by a comparison with the stimulation or inhibition of the growth of Escherichia coli cells in the catholyte and anolyte of the complete nutrient medium M 9. It was shown that medium M 9 prepared on the catholytes of different initial solutions acquired the stimulating properties only if the initial solution contained salts containing chlorine. The stimulating effect of the initial solution was 18-24%. Electrochemical treatment of solutions containing no chlorides (distilled water, phosphate buffer) and subsequent addition of the components of nutrient medium to exposed solutions had neither a stimulating nor the inhibiting effect on cell growth. The cultivation of cells in a nutrient medium based on the catholyte of preliminarily treated hydrochloric acid showed that it is the presence of chlorine ions in solution during electrolysis that causes the stimulating effect of the nutrient medium based on the catholyte. The formation of oxidizers and the inhibitory effect of the anolyte described previously was also observed if the solution contained chlorine ions during electrolysis. Possible mechanisms of the biological effect of catholytes containing chlorides during electrolysis were discussed.

  17. Inhibition of acid formation by epidermal growth factor in the isolated rabbit gastric glands.

    PubMed Central

    Dembiński, A; Drozdowicz, D; Gregory, H; Konturek, S J; Warzecha, Z

    1986-01-01

    The effects of epidermal growth factor (EGF) on basal and stimulated (with histamine, dibutyryl cyclic AMP, and high concentrations of K+) acid formation have been studied in isolated glands from the rabbit gastric mucosa. The changes in the accumulation of [14C]aminopyrine [14C]AP have been used as an indirect measurement of acid production in the glands. Unstimulated gastric glands accumulated [14C]AP indicating the existence of basal acid production in these glands, and EGF caused a small but significant reduction in basal [14C]AP uptake. A similar reduction of basal [14C]AP uptake was observed after exposure to omeprazole but not after ranitidine or prostaglandin E2 (PGE2). Histamine, dibutyryl cyclic AMP and K+ caused a strong and dose-dependent stimulation of acid formation by the glands. EGF, like omeprazole, reduced dose-dependently the [14C]AP accumulation stimulated by both histamine and dibutyryl cyclic AMP, while ranitidine and PGE2 reduced histamine- but not dibutyryl-cyclic-AMP-stimulated accumulation of [14C]AP. In the absence of other external stimuli, an increased K+ concentration enhanced [14C]AP accumulation to levels similar to those produced by histamine and this effect was not changed by EGF, ranitidine or PGE2 but was inhibited by omeprazole. We conclude that EGF interferes with the final steps of acid production between cyclic nucleotides and proton pump of the parietal cells. PMID:3025433

  18. Inhibition of the growth of yeasts in fermented salads.

    PubMed

    Bonestroo, M H; de Wit, J C; Kusters, B J; Rombouts, F M

    1993-02-01

    Salads composed of vegetables and/or meat in an oil-in-water emulsion were prepared by fermentation for 7 h at 42 degrees C or 45 degrees C with strains of Lactobacillus spp. Their stability towards spoilage yeasts was studied using Saccharomyces cerevisiae, Saccharomyces exiguus and Torulaspora delbrueckii, isolated from salads, as well as Pichia membranaefaciens and Zygosaccharomyces bailii. Salads fermented with good lactic starters usually had pH values of < or = 4.2 and lactic acid concentrations of 0.28 to 0.43% (w/w). High numbers of spoilage yeasts (and production of large volumes of CO2) were not attained in these salads, provided the initial concentration of spoilage yeasts was sufficiently low (< or = 100 CFU/g). Inhibition of spoilage yeasts in lactic fermented salads is probably due to lactic acid, the low storage temperature and the low residual oxygen concentration.

  19. Androglobin knockdown inhibits growth of glioma cell lines

    PubMed Central

    Huang, Bo; Lu, Yi-Sheng; Li, Xia; Zhu, Zhi-Chuan; Li, Kui; Liu, Ji-Wei; Zheng, Jing; Hu, Ze-Lan

    2014-01-01

    Globin family was famous for oxygen supply function of its members such as hemoglobin and myoglobin. With the progress of research, several members of this protein family have been proven to play roles in tumors including glioma. Androglobin (ADGB) is a recently identified member of globin family with very few studies about its function. In the present study, we show that ADGB plays an oncogene role in glioma. Lentiviral vector mediated ADGB knockdown inhibited the proliferation of glioma cell lines determined by MTT assay and colony formation assay. ADGB knockdown also increased the apoptosis of glioma cell line U251 assessed by flow cytometry. In addition, western blot showed that ADGB knockdown altered levels of several proteins related to proliferation, survival or apoptosis in U251 cells. These findings suggest ADGB is involved in the progression of glioma in vitro. PMID:24966926

  20. Aurora kinase B/C inhibition impairs malignant glioma growth in vivo.

    PubMed

    Diaz, Roberto Jose; Golbourn, Brian; Shekarforoush, Maryam; Smith, Christian A; Rutka, James T

    2012-07-01

    Inhibition of Aurora kinase B has been evaluated as a therapy to block solid tumor growth in breast cancer, hepatocellular carcinoma, lung adenocarcinoma, and colorectal cancer models. Aurora kinase inhibitors are in early clinical trials for the treatment of leukemia. We hypothesized that Aurora B inhibition would reduce malignant glioma cell viability and result in impaired tumor growth in vivo. Aurora B expression is greater in cultured malignant glioma U251 cells compared to proliferating normal human astrocytes, and expression is maintained in U251 flank xenografts. Aurora B inhibition with AZD1152-HQPA blocked cell division in four different p53-mutant glioma cell lines (U251, T98G, U373, and U118). AZD1152-HQPA also inhibited Aurora C activation loop threonine autophosphorylation at the effective antiproliferative concentrations in vitro. Reduction in cell viability of U251 (p53(R273H)) cells was secondary to cytokinesis blockade and apoptosis induction following endoreplication. AZD1152-HQPA inhibited the growth of U251 tumor xenografts and resulted in an increase in tumor cell apoptosis both in vitro and in vivo. Subcutaneous administration of AZD1152-HQPA (25 mg/kg/day × 4 days; 2 cycles spaced 7 days apart) resulted in a prolongation in median survival after intracranial inoculation of U251 cells in mice (P = 0.025). This is the first demonstration that an Aurora kinase inhibitor can inhibit malignant glioma growth in vivo at drug doses that are clinically relevant.

  1. Acetylsalicylic acid inhibits cell proliferation by involving transforming growth factor-beta.

    PubMed

    Redondo, Santiago; Santos-Gallego, Carlos G; Ganado, Patricia; García, Marta; Rico, Laura; Del Rio, Marcela; Tejerina, Teresa

    2003-02-04

    Acetylsalicylic acid (ASA) inhibits cell proliferation. This may be mediated by transforming growth factor-beta (TGF-beta). TGF-beta directly stops cell proliferation, restrains cells in G(0), and inhibits the uptake of platelet-derived growth factor and insulin-like growth factor. These effects are identical to those observed with ASA treatment. We cultured rat thoracic aorta vascular smooth muscle cells and measured cytotoxicity, cell proliferation, cell cycle, transcription of TGF-beta1, and concentration of TGF-beta1 in supernatant medium. ASA dose-dependently restrained cells in G(0) phase with no cytotoxic effect and inhibited cell proliferation by 30.86%. Anti-TGF-beta1 reversed this inhibition by 30.21%. However, ASA treatment decreased TGF-beta1 transcription and had no significant effect on TGF-beta1 concentration. TGF-beta seems to play an important role in ASA-mediated inhibition of cell proliferation. Therefore, treatment with ASA prevents coronary disease not only by means of its antiplatelet properties but also by an important inhibition of plaque growth. This relationship between ASA and TGF-beta explains many other effects, such as cancer chemoprevention, immunomodulation, and wound healing. The aim of this study was to demonstrate this link.

  2. Fractionation of high molecular weight tannins in grape seed extract and identification of procyanidin B2-3,3'-di-O-gallate as a major active constituent causing growth inhibition and apoptotic death of DU145 human prostate carcinoma cells.

    PubMed

    Agarwal, Chapla; Veluri, Ravikanth; Kaur, Manjinder; Chou, Shen-Chieh; Thompson, John A; Agarwal, Rajesh

    2007-07-01

    Several studies have documented the anticancer and chemopreventive efficacy of grape seed extract (GSE) against various malignancies including prostate cancer (PCA). GSE is a complex mixture of polyphenols including gallic acid (GA), catechin (Cat), epicatechin (Epi) and procyanidins-oligomers of Cat and Epi, some of which are esterified with GA. Initial studies to identify the GSE components cytotoxic to human prostate carcinoma (DU145) cells demonstrated that GA and several crude chromatographic fractions containing procyanidin dimers and trimers were biologically active. The focus of the present work was to purify 14 procyanidins from the fractions and to identify those with highest activity toward growth inhibition, cell death and apoptosis in DU145 cells. The most active procyanidin was identified by mass spectrometry and enzymatic hydrolysis as the 3,3'-di-O-gallate ester of procyanidin dimer B2 (Epi-Epi). B2-digallate exhibited dose-dependent effects on DU145 cells over the range 25-100 microM, whereas GA exhibited comparable activity at lower doses but was highly lethal at 100 microM. Structure-activity studies demonstrated that all three hydroxyl groups of GA are necessary for activity, but a free carboxylic acid group is not required even though esterification reduced the activity of GA. These data, and the fact that non-esterified B2 exhibited little or no activity, suggest that the galloyl groups of B2-digallate are primarily responsible for its effects on DU145 cells. Taken together, these data identify procyanidin B2-3,3'-di-O-gallate as a novel biologically active agent in GSE that should be studied in greater detail to determine its effects against PCA.

  3. Dual effect of metformin on growth inhibition and oestradiol production in breast cancer cells.

    PubMed

    Rice, S; Pellat, L; Ahmetaga, A; Bano, G; Mason, H D; Whitehead, S A

    2015-04-01

    Evidence has been accumulating for a role for metformin in reducing breast cancer risk in post-menopausal women. It inhibits growth of breast cancer cells via several mechanisms, primarily the AMPK/mTOR signalling pathway. Another possible protective mechanism may be the ability of metformin to inhibit aromatase activity. In the present study, we investigated the effects of metformin on the basal growth of MCF-7 cells, after oestradiol (E2) stimulation and after the inhibition of mTOR by rapamycin. Secondly, we investigated the effects of metformin on the activity of a number of steroidogenic enzymes and the mRNA expression of aromatase and steroid sulphatase (STS). High doses of metformin significantly inhibited both basal and oestrogen-stimulated cell division. Low-dose rapamycin (10-10 M) did not inhibit growth, but the addition of metformin induced a significant reduction in growth. High-dose rapamycin (10-8 M) inhibited growth, and this was further attenuated by the addition of metformin. Exposure to low (10-7 M) and high (10-4 M) doses of metformin for 7-10 days significantly reduced the conversion of androstenedione (ANDRO) and testosterone (TESTO) (both requiring aromatase), but not the conversion of oestrone or oestrone sulphate (ES) via 17β-hydroxysteroid dehydrogenase/sulphatase to E2. This attenuation was via a downregulation in the expression of to