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11.
Tadi K Chang Y Ashok BT Chen Y Moscatello A Schaefer SD Schantz SP Policastro AJ Geliebter J Tiwari RK 《Biochemical and biophysical research communications》2005,337(3):1019-1025
Considerable epidemiological evidence exists to link thyroid disease with differing patterns of dietary consumption, in particular, cruciferous vegetables. We have been studying the anti-thyroid cancer (TCa) activity of indole-3-carbinol (I3C) found in cruciferous vegetables and its acid catalyzed dimer, 3,3'-diindolylmethane (DIM). There are no studies as yet to elucidate the effect of these compounds on the altered proliferative patterns in goiter or thyroid neoplasia. In this study, we tested the anti-proliferative effects of I3C and DIM on four different thyroid cancer cell lines representative of papillary (B-CPAP and 8505-C) and follicular carcinoma of the thyroid (CGTH-W-1 and ML-1), and primary human goiter cells. Cell survival and IC50 values for I3C and DIM were calculated by the XTT assay and cell cycle distribution analysis was done by flow cytometry. DIM was found to be a better anti-proliferative agent than I3C in both papillary and follicular TCa resulting in a greater cytotoxic effect at a concentration over three fold lower than predicted by the molar ratio of DIM and I3C. The anti-proliferative activity of DIM in follicular TCa was mediated by a G1 arrest followed by induction of apoptosis. DIM also inhibited the growth of primary goiter cells by 70% compared to untreated controls. Contrary to traditional belief that cruciferous vegetables are "goitrogenic", DIM has anti-proliferative effects in glandular thyroid proliferative disease. Our preclinical studies provide a strong rationale for the clinical exploration of DIM as an adjuvant to surgery in thyroid proliferative disease. 相似文献
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Catrin Albrecht Ad M Knaapen Andrea Becker Doris H?hr Petra Haberzettl Frederik J van Schooten Paul JA Borm Roel PF Schins 《Respiratory research》2005,6(1):129
Persistent inflammation and associated excessive oxidative stress have been crucially implicated in quartz-induced pulmonary diseases, including fibrosis and cancer. We have investigated the significance of the particle surface reactivity of respirable quartz dust in relation to the in vivo generation of reactive oxygen and nitrogen species (ROS/RNS) and the associated induction of oxidative stress responses in the lung. Therefore, rats were intratracheally instilled with 2 mg quartz (DQ12) or quartz whose surface was modified by either polyvinylpyridine-N-oxide (PVNO) or aluminium lactate (AL). Seven days after instillation, the bronchoalveolar lavage fluid (BALF) was analysed for markers of inflammation (total/differential cell counts), levels of pulmonary oxidants (H2O2, nitrite), antioxidant status (trolox equivalent antioxidant capacity), as well as for markers of lung tissue damage, e.g. total protein, lactate dehydrogenase and alkaline phosphatase. Lung homogenates as well as sections were investigated regarding the induction of the oxidative DNA-lesion/oxidative stress marker 8-hydroxy-2''-deoxyguanosine (8-OHdG) using HPLC/ECD analysis and immunohistochemistry, respectively. Homogenates and sections were also investigated for the expression of the bifunctional apurinic/apyrimidinic endonuclease/redox factor-1 (APE/Ref-1) by Western blotting and immunohistochemistry. Significantly increased levels of H2O2 and nitrite were observed in rats treated with non-coated quartz, when compared to rats that were treated with either saline or the surface-modified quartz preparations. In the BALF, there was a strong correlation between the number of macrophages and ROS, as well as total cells and RNS. Although enhanced oxidant generation in non-coated DQ12-treated rats was paralleled with an increased total antioxidant capacity in the BALF, these animals also showed significantly enhanced lung tissue damage. Remarkably however, elevated ROS levels were not associated with an increase in 8-OHdG, whereas the lung tissue expression of APE/Ref-1 protein was clearly up-regulated. The present data provide further in vivo evidence for the crucial role of particle surface properties in quartz dust-induced ROS/RNS generation by recruited inflammatory phagocytes. Our results also demonstrate that quartz dust can fail to show steady-state enhanced oxidative DNA damage in the respiratory tract, in conditions were it elicits a marked and persistent inflammation with associated generation of ROS/RNS, and indicate that this may relate to compensatory induction of APE/Ref-1 mediated base excision repair. 相似文献
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A defined minimal medium has been developed which is either restrictive or permissive for the production of ochratoxin A byPenicillium verrucosum simply by changing the nitrogen and carbon source. The combination of ammonium/glycerin promoted, whereas the combination nitrate/glucose repressed ochratoxin production.In parallel mutants ofP verrucosum have been constructed by restriction endonuclease mediated integration, which were not able to produce ochratoxin. Different types of transformants, which either produce no detectable amounts of ochratoxin A but ochratoxin α, strains which produce only ochratoxin B and strains which produces none of these secondary metabolites, have been observed. 相似文献
16.
Structural comparison of fibroblast growth factor-specific heparan sulfates derived from a growing or differentiating neuroepithelial cell line 总被引:3,自引:1,他引:2
Brickman YG; Nurcombe V; Ford MD; Gallagher JT; Bartlett PF; Turnbull JE 《Glycobiology》1998,8(5):463-471
Heparan sulfate (HS) glycosaminoglycans are essential modulators of
fibroblast growth factor (FGF) activity both in vivo and in vitro, and
appear to act by cross-linking particular forms of FGF to appropriate FGF
receptors. We have recently isolated and characterized two separate HS
pools derived from immortalized embryonic day 10 mouse neuroepithelial 2.3D
cells: one from cells in log growth phase, which greatly potentiates the
activity of FGF-2, and the other from cells undergoing contact-inhibition
and differentiation, which preferentially activates FGF-1. These two pools
of HS have very similar functional activities to those species isolated
from primary neuroepithelial cells at corresponding stages of active
proliferation or differentiation. We present here a structural comparison
between these cell line HS species to establish the nature of the changes
that occur in the biosynthesis of HS. A combination of chemical and
enzymatic cleavage, low pressure chromatography and strong anion-exchange
HPLC were used to generate full chain models of each species. Overall, the
HS pools synthesized in the dividing cell line pools possessed less complex
sulfation than those derived from more differentiated, growth arrested
cells.
相似文献
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Heterologous expression of an engineered truncated form of human Lewis fucosyltransferase (Fuc-TIII) by the methylotrophic yeast Pichia pastoris 总被引:1,自引:0,他引:1
Gallet PF; Vaujour H; Petit JM; Maftah A; Oulmouden A; Oriol R; Le Narvor C; Guilloton M; Julien R 《Glycobiology》1998,8(9):919-925
A stable GS115 Pichia pastoris recombinant strain was constructed to
secrete a truncated form of the human alpha(1,3/4) fucosyltransferase
(amino acids 45-361). Enzyme production resulted from a secretory pathway
based on the pre-pro- alpha mating factor signal sequence of the yeast
Saccharomyces cerevisiae . Following its transit through the Golgi
apparatus, the enzyme accumulated in the periplasmic space before its
release in the culture broth (about 30 mg/l). Cell-enclosed enzyme (
approximately 0.16%) proved to be fairly stable for many freezing and
thawing cycles and could be used several times as an immobilized catalyst.
Soluble enzyme (>99.8%) representing the main protein of the culture
broth (10%) has been characterized by Western-blotting, substrate
specificities and kinetic parameters. The two forms (cell- enclosed and
soluble) of recombinant enzyme may be used for in vitro synthesis of
Lewisadeterminants.
相似文献
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Cotransmission of divergent relapsing fever spirochetes by artificially infected Ornithodoros hermsi
The soft tick Ornithodoros hermsi, which ranges in specific arboreal zones of western North America, acts as a vector for the relapsing fever spirochete Borrelia hermsii. Two genomic groups (genomic group I [GGI] and GGII) of B. hermsii are differentiated by multilocus sequence typing yet are codistributed in much of the vector's range. To test whether the tick vector can be infected via immersion, noninfected, colony-derived O. hermsi larvae were exposed to reduced-humidity conditions before immersion in culture suspensions of several GGI and GGII isolates. We tested for spirochetes in ticks by immunofluorescence microscopy and in mouse blood by quantitative PCR of the vtp locus to differentiate spirochete genotypes. The immersed larval ticks were capable of spirochete transmission to mice at the first nymphal feeding. Tick infection with mixed cultures of isolates DAH (vtp-6) (GGI) and MTW-2 (vtp-5) (GGII) resulted in ticks that caused spirochetemias in mice consisting of MTW-2 or both DAH and MTW-2. These findings show that this soft tick species can acquire B. hermsii by immersion in spirochete suspensions, that GGI and GGII isolates can coinfect the tick vector by this method, and that these spirochetes can be cotransmitted to a rodent host. 相似文献
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IL Ibañez C Bracalente C Notcovich I Tropper BL Molinari LL Policastro H Durán 《PloS one》2012,7(9):e44502
The Cyclin-dependent kinase inhibitor 1B (p27Kip1) is a key protein in the decision between proliferation and cell cycle exit. Quiescent cells show nuclear p27Kip1, but this protein is exported to the cytoplasm in response to proliferating signals. We recently reported that catalase treatment increases the levels of p27Kip1 in vitro and in vivo in a murine model. In order to characterize and broaden these findings, we evaluated the regulation of p27Kip1 by hydrogen peroxide (H(2)O(2)) in human melanoma cells and melanocytes. We observed a high percentage of p27Kip1 positive nuclei in melanoma cells overexpressing or treated with exogenous catalase, while non-treated controls showed a cytoplasmic localization of p27Kip1. Then we studied the levels of p27Kip1 phosphorylated (p27p) at serine 10 (S10) and at threonine 198 (T198) because phosphorylation at these sites enables nuclear exportation of this protein, leading to accumulation and stabilization of p27pT198 in the cytoplasm. We demonstrated by western blot a decrease in p27pS10 and p27pT198 levels in response to H(2)O(2) removal in melanoma cells, associated with nuclear p27Kip1. Melanocytes also exhibited nuclear p27Kip1 and lower levels of p27pS10 and p27pT198 than melanoma cells, which showed cytoplasmic p27Kip1. We also showed that the addition of H(2)O(2) (0.1 μM) to melanoma cells arrested in G1 by serum starvation induces proliferation and increases the levels of p27pS10 and p27pT198 leading to cytoplasmic localization of p27Kip1. Nuclear localization and post-translational modifications of p27Kip1 were also demonstrated by catalase treatment of colorectal carcinoma and neuroblastoma cells, extending our findings to these other human cancer types. In conclusion, we showed in the present work that H(2)O(2) scavenging prevents nuclear exportation of p27Kip1, allowing cell cycle arrest, suggesting that cancer cells take advantage of their intrinsic pro-oxidant state to favor cytoplasmic localization of p27Kip1. 相似文献