bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein kinase A inhibitors enhance radiation‐induced apoptosis
Authors: Findik Duygu , Song Qizhong , Hidaka Hiroyoshi , Lavin Martin 
Published: May 2005

AbstractIn addition to a role for de novo protein synthesis in apoptosis we have previously shown that activation of a protein phosphatase or loss of activity of a kinase is also important in radiation‐induced apoptosis in human cells [Baxter, and Lavin (1992): J Immunol 148:149–1954]. We show here that some inhibitors of protein kinases exacerbate radiation‐induced apoptosis in the human cell line BM13674. The specific protein kinase A inhibitor isoquinoline sulfonamide (20 μM) gave rise to significantly increased levels of apoptosis at 2–6 h postirradiation compared to values after radiation exposure only. The same concentration of isoquinolinesulfonamide, which was effective in increasing apoptosis, reduced activity markedly. A 66% inhibition of cyclic AMP‐dependent protein kinase A activity occurred in unirradiated cells at this concentration of H89 and activity was reduced to 58% in irradiated cells. Calphostin C, a specific inhibitor of protein kinase C, at a concentration of 0.1 μM, which caused 68% inhibition of enzyme activity in irradiated cells, failed to enhance the level of radiation‐induced apoptosis. Other kinase inhibitors did not lead to an additional increase in apoptosis over and above that observed after irradiation. The results obtained here provide further support for an important role for modification of existing proteins during radiation‐induced apoptosis.
Characterization of an endooligopeptidase A‐like protein in PC12 cells: Activity modulation by cAMP but not by basic fibroblast growth factor
Authors: Ferro Emer S. , Tambourgy Denise V. , Abreu Patricia A. E. , Camargo Antonio C. M. , Raw Isaias , Ho Paulo L. 
Published: May 2005

AbstractEndooligopeptidase A is a putative neuropeptide‐metabolizing enzyme. It converts small enkephalin‐containing peptides into the corresponding enkephalins and inactivates biopeptides such as bradykinin and neurotensin in vitro. We investigated the presence of endooligopeptidase A in PC12 cells. This cell line was derived from a rat pheochromocytoma tumor and resembles fetal chromaffin cell. Depending on the supplements added to the cell culture, this cell line can be differentiated into mature chromaffin cell or sympathetic neuron‐like cell. Endooligopeptidase A activity was measured in soluble cellular extracts using a specific fluorogenic substrate QF‐ERP7. The PC12 endooligopeptidase A‐like activity shared similar but not identical biochemical properties with rabbit brain endooligopeptidase A. Similarly to rabbit brain endooligopeptidase A, the PC12 endooligopeptidase A‐like activity was enhanced by DTT, totally inhibited by DTNB and 1‐10 Phenanthroline, partially inhibited by cFP‐AAF‐pAb, and not affected by PMSF. Furthermore, the PC12 endooligopeptidase A‐like activity displayed identical elution profile as rabbit brain endooligopeptidase A in gel filtration and anion‐exchange chromatography. In addition, an antiserum raised against rabbit brain endooligopeptidase A cross‐reacted with a 71 kDa component from PC12 cell extracts in Western blotting and was also able to partially neutralize the PC12 endooligopeptidase A‐like activity. Treatment of PC12 cells with basic fibroblast growth factor (bFGF), a neurotrophic factor for this cell line, did not modify the specific activity of this enzyme. However, cAMP analogs decreased the specific activity of the enzyme. These results indicate the presence of an endooligopeptidase A‐like activity in PC12 cells which is modulated by cAMP but not by bFGF.
Calcium transport in epithelial cells of the intestine and kidney
Authors: Kumar Rajiv 
Published: May 2005

AbstractThe central role of 1α,25‐dihydroxyvitamin D3 in the regulation of calcium balance is well established. By increasing the absorption of calcium in the intestine and the reabsorption of filtered calcium in the kidney tubule, the hormone maintains an appropriate calcium balance. The cellular mechanisms that underlie the increase in calcium transport in epithelial cells in response to 1α,25‐dihydroxyvitamin D3 are beginning to be defined. These events include an increase in the movement of calcium across the apical membrane of the cell, an increase in the movement of calcium across the cell, and an increase in the extrusion of calcium at the basolateral portion of the cell. In this Prospects article, I will discuss the nature of the various processes and proteins involved in transcellular calcium movement, and I will attempt to highlight various future areas of research.
Differential heme oxygenase induction by stannous and stannic ions in the heart
Authors: Neil Teresa K. , Abraham Nader G. , Levere Richard D. , Kappas Attallah 
Published: May 2005

AbstractHeme oxygenase is the rate‐limiting enzyme in heme catabolism, and is induced by oxidative stress, foreign and endogenous chemicals, and many trace elements and heavy metals. This study examined the effect of the oxidative state of the heavy metal tin, on heme oxygenase‐1 induction in cardiac tissue. Subcutaneous administration of stannous and stannic chloride failed to induce the enzyme in this tissue. Atomic absorption spectroscopy revealed the absence of tin in the heart cells. Investigation of several metal formulations showed that both stannous and stannic citrate were able to enter the bloodstream from the injection site and into heart tissue. Northern blot analysis revealed that heme oxygenase‐1 mRNA was elevated several‐fold in rat hearts from animals which received either stannous or stannic citrate, and that mRNA levels corresponded with the increase in enzyme activity. The presence of citrate facilitated the transport of the tin ion into the blood stream and possibly across cardiac cell membrane. The stannous ion was more potent as an inducer of heme oxygenase than was the stannic ion.
Domains of the human androgen receptor and glucocorticoid receptor involved in binding to the nuclear matrix
Authors: van Steensel Bas , Jenster Guido , Damm Klaus , Brinkmann Albert O. , van Driel Roel 
Published: May 2005

AbstractSteroid receptors have been reported to bind to the nuclear matrix. The nuclear matrix is operationally defined as the residual nuclear structure that remains after extraction of most of the chromatin and all soluble and loosely bound componnets. To obtain insight in the molecular mechanism of the interaction of steroid receptors with the nuclear matrix, we studied the binding of several deletion mutants of the human androgen receptor (hAR) and the human glucocorticoid receptor (hGR) to the nuclear matrix. Receptor binding was tested for two different nuclear matrix preparations: complete matrices, in which most matrix proteins are retained during the isolation procedure, and depleted matrices, which consist of only a subset of these proteins. The results show that the C‐terminal domain of the hAR binds tightly to both depleted and complete matrices. In addition, at least one other domain of the hAR binds to complete matrices but not to depleted matrices. In contrast to the hAR, the hGR binds only to complete matrices. For this interaction both the DNA‐binding domain and the C‐terminal domain of the hGR are required, whereas the N‐terminal domain is not. We conclude that specific protein domains of the hAR and the hGR are involved in binding to the nuclear matrix. In addition, our results indicate that the hAR and the hGR are attached to the nuclear matrix through different molecular interactions.
Malignant transformation by H‐ras results in aberrant regulation of ribonucleotide reductase gene expression by transforming growth factor‐β1
Authors: Hurta Robert A. R. , Wright Jim A. 
Published: May 2005

AbstractRibonucleotide reductase is a key rate‐limiting and regulatory step in DNA synthesis and plays a crucial role in the coordination of DNA synthesis, DNA repair, and cell proliferation. The present study demonstrates a link between alterations in TGF‐β1 regulation during malignant conversion and the expression of ribonucleotide reductase. H‐ras‐transformed mouse 10T1/2 cell lines exhibiting malignant potential were examined for possible TGF‐β1‐mediated alterations in ribonucleotide reductase expression. Selective induction of ribonucleotide reductase gene expression occurred, since only H‐ras‐transformed highly metastatic cells exhibited marked elevations in ribonucleotide reductase expression, whereas nontransformed normal 10T1/2 cells were unaffected by TGF‐β1 treatment. These changes occurred without any detectable modifications in DNA synthesis rates, suggesting that these changes were regulated by a novel mechanism independent of the S‐phase of the cell cycle. Furthermore, this TGF‐β1‐mediated regulation of ribonucleotide reductase expression was shown to occur through an autocrine mechanism. TGF‐β1‐modulated regulation of ribonucleotide reductase expression requires de novo protein synthesis and involves, at least in part, transcriptional and post‐transcriptional events. Furthermore, evidence is presented to suggest a possible role for protein kinase C‐mediated events, protein phosphatases, and G‐protein‐coupled events in the TGF‐β1‐mediated regulation of ribonucleotide reductase expression in H‐ras‐transformed malignant cells. TGF‐β1 regulation of ribonucleotide reductase in highly malignant cells appears to be complex and multifaceted and constitutes an integral part of an altered growth regulatory program.
Suppression of collagenase gene expression by all‐trans and 9‐cis retinoic acid is ligand dependent and requires both RARs and RXRs
Authors: Pan Luying , Eckhoff Christian , Brinckerhoff Constance E. 
Published: May 2005

AbstractRetinoic acids (RA) are active metabolites of vitamin A which affect the expression of many genes involved in embryonic development, cell differentiation, and homeostasis. One important target gene for RA is matrix metalloproteinase (MMP‐1, collagenase), the only enzyme active at neutral pH that can degrade interstitial collagen, a major component of extracellular matrix. Using a cell line of normal rabbit synovial fibroblasts, HIG82 cells, as a model, we report that both all‐trans‐ and 9‐cis‐RA inhibit collagenase synthesis. This inhition occurs at a transcriptional level and is ligand‐dependent. Constitutive levels of retinoic acid receptor (RAR) mRNA levels are low, but are increased by all‐trans and by 9‐cis RA. In contrast, consitutive levels of retinoid X receptor (RXR) mRNA are higher and are not affected by RA. To measure DNA/protein interactions, we used a gel mobility shift assay with oligonucleotides containing either an AP‐1 site or a 40 bp region between −182/ −141, nuclear extracts from RT‐treated cells, and antibodies to RARs and RXRs. We found that both RARs and RXRs interact with these regions of the collagenase promoter, perhaps as part of a complex with other proteins. Our results suggest that heterodimers between RARs and RXRs mediate suppression of the collagenase gene by RA, and that RAR is a limiting factor in this negative regulation.
Post‐translational abnormality of the type II cyclic AMP‐dependent protein kinase in psoriasis: Modulation by retinoic acid
Authors: Tournier Sylvie , Gerbaud Pascale , Anderson Wayne B. , Lohmann Suzane M. , Evain‐Brion Danièle , Raynaud Françoise 
Published: May 2005

AbstractPreviously, we have reported a decrease in the binding of a cAMP analog to the regulatory subunits of cAMP‐dependent protein kinase (cAMP‐PK), as well as a decrease in cAMP‐PK activities, in psoriatic cells. Retinoic acid (RA) treatment of these cells can induce an increase in cAMP‐PK toward normal levels. To better define the effect of retinoic acid on the cAMP‐PK system in psoriatic fibroblasts, Western blot analysis using an RIIα specific antibody and in vivo phosphorylation experiments were carried out to determine possible changes in the RII regulatory subunit. Our results indicate a decrease in the binding of the cAMP analog 8‐azido‐[32P]‐cAMP with no change in the level of RII protein in psoriatic fibroblasts. In addition, by two‐dimensional gel electrophoresis we observed the presence of a phosphorylated form of RII unique to psoriatic cells which is suppressed by RA treatment. This study suggests an altered posttranslational modification of the cAMP‐PKII in psoriatic fibrobiasts which can be reversed by exposure of these cells to RA.
POU‐domain gene expression in the gastrointestinal tract
Authors: Fuller Peter J. , Beveridge Dianne J. , Taylor Russell G. 
Published: May 2005

AbstractThe process of self‐renewal which occurs in the gastrointestinal epithelium is greatly amplified and accelerated during the intestinal adaptation which occurs in the residual ileum after massive small bowel resection (MSBR). As with growth and development, these processes must involve the coordinated regulation of many genes. Several families of nuclear proteins are known to be involved in the control of gene expression during development including the POU‐domain genes; their expression has not been characterized in the gastrointestinal tract during normal cellular renewal or adaptation, and POU‐domain encoding cDNAs were cloned from ileal RNA. Three known genes were cloned: Oct‐1, Brn‐1 and Tst‐1 but no novel members of this gene family were identified. The encoded sequence for rat Oct‐1 differs from that previously reported. Oct‐1 is relatively ubiquitously expressed with increased expression during both development and adaptation. Minimal expression of Tst‐1 was observed. Brn‐1 exhibits limited expression in the adult gastrointestinal tract. but may play a role in the fetal gastrointestinal tract.
Mouse uterus peptidylarginine deiminase is expressed in decidual cells during pregnancy
Authors: Arai Tomoji , Kusubata Masashi , Kohsaka Tetsuya , Shiraiwa Masakazu , Sugawara Kiyoshi , Takahara Hidenari 
Published: May 2005

AbstractPeptidylarginine deiminase is localized in the cytosol of the luminal and glandular epithelia of the nonpregnant murine uterus and its expression is regulated by sex hormones [Takahara et al., [1989]: J Biol Chem 264, 13361–13368; Takahara et al. [1992]: J Biol Chem 267,520–525]. Here, we demonstrate that changes occur in the enzyme level in the mouse uterus during pregnancy and parturition. After a rapid decrease in enzymatic activity from day 1 to day 5 of pregnancy, the activity sharply increased during the middle stage of pregnancy (day 8 to day 10) and then gradually decreased during late pregnancy. Expression of the enzyme occurred only in the decidual cells that had differentiated from endometrial stroma cells surrounding the implantation site. The immunochemical properties of the enzyme expressed in the decidualized cells was indistinguishable from those in the uterine epithelia. These results suggest that peptidylarginine deiminase has important roles in decidual cells and not just in the epithelia. These results suggest that peptidylarginine deiminase has important roles in decidual cells and not just in the epithelia of the nonpregnant uterus. Moreover, the level of enzyme activity increased slightly just before parturition (day 17), and then decreased during the 12 h period after parturition. The tissue localization of the enzyme expressed around the time of parturition changed from decidua to the luminal and glandular epithelia. Semiquantitative analyses of the enzyme mRNA content in the pregnant uteri showed a remarkable increase from day 7 leading to the onset of the enzyme synthesis in the decidual cells. After reaching the maximal level at day 12, small peaks in the mRNA level were observed at two times during late pregnancy. Since these serial changes in the mRNA level did not correlate with changes in sex hormones, the expression of decidual peptidylarginine deiminase seemed to be controlled by factors other than sex hormones.
Induction of tissue inhibitor and matrix metalloproteinase by serum in human heart‐derived fibroblast and endomyocardial endothelial cells
Authors: Tyagi Suresh C. , Kumar G. Suresh , Glover Geraldine 
Published: May 2005

AbstractTo understand the regulatory mechanisms of extracellular matrix (ECM) turnover and proteinase expression in human cardiovascular tissue, we have isolated and characterized human heart fibroblast (HHF) and human heart endothelial (HHE) cells from endomyocardial biopsy specimens. HHE cell in culture exhibited the typical cobblestone growth pattern and positive immunofluorescent staining for factor Vlll related antigen. HHF demonstrated the typical spindle shape during culture and were positive for vimentin. Both cell types were negative for a‐actin, indicating that these cells were of nonmuscle origin. Cell growth studies revealed significant growth when maintained in limiting serum concentration, suggesting mitogenic activity of these cells, and demonstrated growth inhibitory activity when grown in serum‐free medium. Serum‐dependent matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression was measured by zymography, immunoblot, and Northern blot analysis. Results indicated that serum induces both the MMP and TlMP expression at the mRNA and protein levels in a dose‐dependent manner. This induction was inhibited by actinomycin D and cycloheximide, suggesting transcriptional and translational regulation of MMP and TIMP. Indirect immunofluorescence labeling indicated expression of MMP and TlMP in HHF and HHE cells. These results suggested that the serum induces proliferation as well as expression of MMP and TlMP in HHE and HHF cells. The growth inhibitory activity of these cell cultures will enable us to explore further the nature of this response and compare this phenomenon with other growth inhibitors and growth promoters identified in other normal and transformed cells.
Melatonin administration prevents lipopolysaccharide‐induced oxidative damage in phenobarbital‐treated animals
Authors: Sewerynek Ewa , Abe Mitsushi , Reiter Russel J. , Barlow‐Walden Lornell R. , Chen Lidun , McCabe Timothy J. , Roman Linda J. , Diaz‐Lopez Beatriz 
Published: May 2005

AbstractThe protective effect of melatonin on lipopolysaccharide (LPS)‐induced oxidative damage in phenobarbital‐treated rats was measured using the following parameters: changes in total glutathione (tGSH) concentration, levels of oxidized glutathione (GSSG), the activity of the antioxidant enzyme glutathione peroxidase (GSH‐PX) in both brain and liver, and the content of cytochrome P450 reductase in liver. Melatonin was injected intraperitoneally (ip, 4mg/kg BW) every hour for 4 h after LPS administration; control animals received 4 injections of diluent. LPS was given (ip, 4 mg/kg) 6 h before the animals were killed. Prior to the LPS injection, animals were pretreated with phenobarbital (PB), a stimulator of cytochrome P450 reductase, at a dose 80 mg/kg BW ip for 3 consecutive days. One group of animals received LPS together with Nw‐nitro‐L‐arginine methyl ester (L‐NAME), a blocker of nitric oxide synthase (NOS) (for 4 days given in drinking water at a concentration of 50 mM). In liver, PB, in all groups, increased significantly both the concentration of tGSH and the activity of GSH‐PX. When the animals were injected with LPS the levels of tGSH and GSSG were significantly higher compared with other groups while melatonin and L‐NAME significantly enhanced tGSH when compared with that in the LPS‐treated rats. Melatonin alone reduced GSSG levels and enhanced the activity of GSH‐PX in LPS‐treated animals. Additionally, LPS diminished the content of cytochrome P450 reductase with this effect being largely prevented by L‐NAME administration. Melatonin did not change the content of P450 either in PB‐ or LPS‐treated animals. In brain, melatonin and L‐NAME increased both tGSH levels and the activity of GSH‐PX in LPS‐treated animals. The results suggest that melatonin protects against LPS‐induced oxidative toxicity in PB‐treated animals in both liver and brain, and the findings are consistent with previously published observations related to the antioxidant activity of the pineal hormone.
Metabolism of 3H‐1α,25‐dihydroxyvitamin D3 in cultured human keratinocytes
Authors: Ray Swapna , Ray Rahul , Holick Michael F. 
Published: May 2005

AbstractIn the present investigation we studied the metabolism of 1α,25‐dihydroxy‐[1β‐3H] vitamin D3 (3H‐1,25(OH)2D3) in culture‐grown human keratinocytes (CHK). Our results showed that the cellular uptake of 3H‐1,25(OH)2D3, upon incubation with CHK, occurred very rapidly; and it paralleled a decrease in the concentration of 3H‐1,25(OH)2D3 in the medium. The amount of 3H‐calcitroic acid, on the other hand, increased slowly in the medium, while the concentration of 3H‐calcitroic acid in the cell remained undetectable during the whole period of incubation. When the cells were preincubated with 1,25(OH)2D3 (10−8M), conversion of 3H‐1,25(OH)2D3 to 3H‐calcitroic acid increased almost twofold, indicating that 1,25(OH)2D3 catalyzed its own catabolism. © 1995 Wiley‐Liss, Inc.
Association of protein kinase FA/GSK‐3α (a proline‐directed kinase and a regulator of protooncogenes) with human cervical carcinoma dedifferentiation/progression
Authors: Yang Shiaw‐Der , Yu Jau‐Song , Lee Tsong‐Tze , Ni Mei‐Hui , Yang Chuan‐Ching , Ho Yat‐Sen , Tsen Tze‐Zen 
Published: May 2005

AbstractComputer analysis of protein phosphorylation‐sites sequence revealed that most transcriptional factors and viral oncoproteins are prime targets for regulation of proline‐directed protein phosphorylation, suggesting an association of proline‐directed protein kinase (PDPK) family with neoplastic transformation and tumorigenesis. In this report, an immunoprecipitate activity assay of protein kinase FA/glycogen synthase kinase‐3α (kinase FA/GSK‐3α) (a particular member of PDPK family) has been optimized for human cervical tissue and used to demonstrate for the first time significantly increased (P < 0.001) activity in poorly differentiated cervical carcinoma (82.8 ± 6.6 U/mg of protein), moderately differentiated carcinoma (36.2 ± 3.4 U/mg of protein), and well‐differentiated carcinoma (18.3 ± 2.4 U/mg of protein) from 36 human cervical carcinoma samples when compared to 12 normal controls (4.9 ± 0.6 U/mg of protein). Immunoblotting analysis further revealed that increased activity of kinase FA/GSK‐3α in cervical carcinoma is due to overexpression of protein synthesis of the kinase. Taken together, the results provide initial evidence that overexpression of protein synthesis of the kinase. Taken together, the results provide initial evidence that overexpression of protein synthesis and cellular activity of kinase FA/GSK‐3α may be involved in human cervical carcinoma dedifferentiation/progression, supporting an association of proline‐directed protein kinase with neoplastic transformation and tumorigenesis. Since protein kinase FA/GSK‐3α may function as a possible regulator of transcription factors/proto‐oncogenes, the results further suggest that kinase FA/GSK‐3α may play a potential role in human cervical carcinogenesis, especially in its dedifferentiation and progression. © 1995 Wiley‐Liss, Inc.