Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:APRD00369 (ROS)
 19,271 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bone metastases of breast cancers produce not only osteolytic but also osteosclerotic lesions. The latter are often observed after androgenic treatment of the tumor. Potential production of osteoblast stimulating activity (ObSA) in breast cancer cell lines, and possible androgen control of this activity have been investigated. Conditioned media (CM) collected from 4 breast cancer cell lines (MCF-7, ZR75, MDA-MB 231, BT20) was tested in vitro on ROS 17/2,8 osteoblast-like cells and on osteoblasts derived from human bone biopsies. The parameters monitored in osteoblasts were [3H]thymidine incorporation, alkaline phosphatase activity, and osteocalcin secretion. Serum-free media conditioned during 24 h by MCF-7 cells presented the highest ObSA. CM decreased thymidine incorporation in DNA and increased alkaline phosphatase activity in a dose-dependent manner. Bone GLA protein (osteocalcin) secretion by human osteoblasts was not increased however in the presence of CM. MCF-7 cells were cultured in the presence of dihydrotestosterone (DHT) [1-100 nM] for 5 days. Serum-free, DHT-free CM collected after an additional 24 h, contained alkaline-phosphatase stimulating activity which was DHT dose-dependent. Estradiol and 1,25(OH)2D3 failed to elicit a comparable increase of the ObSA in the CM. In conclusion, MCF-7 cells product factor(s) that interfere with bone remodeling. The DHT modulation of ObSA parallels the estradiol control of MCF-7 cells osteolytic lesions in relation with Prostaglandin E secretion. Sex hormones at physiological and pharmacological levels might thus control both osteosclerotic and osteolytic lesions observed in bone deposits of hormone dependent cancers.
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PMID:Androgens increase osteoblast-stimulating activity of human breast cancer cells in vitro. 370 24

Angiogenesis is a fundamental process in skeletal development and repair, and previous studies indicate that vascular endothelial growth factor (VEGF), an endothelial cell-specific angiogenic factor, may be involved in bone formation and repair. Therefore, we studied the hormonal regulation of VEGF expression in SaOS-2 osteoblast-like cells, both at the protein level, and at the transcriptional level by transient transfection experiments. 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3], increased VEGF expression by approximately 3-fold, and the increase was dose dependent, with maximum stimulation between 1.0 and 10 nM of 1,25-(OH)2D3. Up-regulation of VEGF protein was detected already after 6 h of treatment. VEGF up-regulation was also observed in ROS-17/2.8 and OHS-4 osteoblast-like cells but not in MCF-7 and MDA-MB231 breast carcinoma cells. Dexamethasone (Dex) decreased VEGF expression to 40% of the control, but when added together with 1,25-(OH)2D3, had no effects on the up-regulation of VEGF by 1,25-(OH)2D3. PTH1-34 stimulated weakly VEGF expression, but combined with 1,25-(OH)2D3, resulted in a close to 5-fold stimulation. A 4-day pretreatment of the cells with Dex increased the vitamin D3 receptor expression and resulted in a stronger stimulation of VEGF by 1,25-(OH)2D3, alone or in combination with PTH1-34. The results show that the VEGF promoter is a target of 1,25-(OH)2D3 regulation in osteoblasts, despite the lack of classical vitamin D3 responsive elements. The up-regulation of VEGF in osteoblast-like cells by calciotropic hormones provides additional evidence of the involvement of VEGF in bone metabolism.
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PMID:1,25-Dihydroxyvitamin D3 induces the expression of vascular endothelial growth factor in osteoblastic cells. 937 8

Cardiovascular diseases represent the first cause of mortality in chronic renal failure patients treated by hemodialysis. Alterations in lipid metabolism and oxidative stress are recognized as vascular risk factors. Their corrections could be of interest for atherosclerosis prevention. In order to evaluate interest of an therapeutic intervention, we have analyzed oxidative metabolism in hemodialysis patients by determining the production of oxygen reactive species (ROS), the level of defense mechanisms, and the balance between nitric oxide (NO) and ROS, responsible for anti- or proxidant effects of NO. During dialysis sessions performed with cellulosic membrane (Cuprophan) an increase in hydroperoxide production by platelets was noted (12 HETE) (5.62 +/- 0.94 pg); similarly, superoxide anion (O2(0)-) production by monocytes (fluorescence index: 115 +/- 24) and by polynuclear cells (fluorescence index: 115 +/- 24) was enhanced. On the other hand, anti-oxidant defenses were significantly reduced with a decrease in RBC SOC activity (0.92 +/- 0.06 U/mg Hg) and in RBC vitamin E (0.7 +/- 0.07 mg/l) concentration. We have demonstrated a profound alteration in the L-arginine/NO pathway consequently to an accumulation of NO synthases inhibitors or activators. The necessity to reduce the production of ROS during dialysis sessions justifies the use of more biocompatible membranes, such as modified cellulosic or synthetic membranes, decreasing leucocyte activation. In addition, NO synthetase inhibitors can be preferentially eliminated by convection. Finally, a supplementation with an exogenous anti-oxidant, such as oral vitamin E (500 mg/day for 6 months) normalizes RBC vitamin E levels and concomitantly allows a decrease in MDA concentrations In conclusion, oxidative metabolism alterations observed in hemodialysis are multifactorial: preventive measures include the use of a more biocompatible material, the reequilibrium of the NO/ROS balance, and supplementation with exogenous anti-oxidants.
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PMID:[Oxidative stress and chronic renal insufficiency: what can be a prophylactic approach?]. 940 62

Certain tumor cells, such as squamous carcinoma cells, express an increased number of epidermal growth factor (EGF) receptors. The goal of this study was the targeted delivery of the photocytotoxic compound Sn(IV)chlorine e6 monoethylenediamine++ (SnCe6(ED)) to tumors that overexpress the EGF receptor. Therefore EGF was conjugated to SnCe6(ED) through a carrier, such as dextran (Dex) and human serum albumin (HSA), followed by the evaluation of the photocytotoxicity on the EGF receptor overexpressing MDA-MB-468 cell line. The photobiologic activity of these conjugates was then compared to a conjugate of the photosensitizer to HSA or dextran, or to the photosensitizer alone. In contrast to EGF-HSA-SnCe6(ED), the affinity of EGF for its receptor was substantially impaired upon conjugation in EGF-Dex-SnCe6(ED). In correlation with these results, EGF-HSA-SnCe6(ED) displayed a high cytotoxicity (IC50, 63 nM) on MDA-MB-468 cells at a light dose of 27 kJ/m2, whereas EGF-Dex-SnCe6(ED) showed very limited photocytotoxicity. In the presence of a competing EGF concentration (10 microM), EGF-HSA-SnCe6(ED) was not cytotoxic anymore. The high photocytoxicity of EGF-HSA-SnCe6(ED) was shown to be a result of a high intracellular concentration in MDA-MB-468 cells, which could be lowered dramatically by incubating the conjugate with a competing EGF concentration. In contrast, EGF-Dex-SnCe6(ED) displayed very poor accumulation in MDA-MB-468 cells, in agreement with its low EGF receptor affinity and photocytoxicity. Besides, it could be demonstrated that EGF-HSA-SnCe6(ED) produced intracellularly ROS (reactive oxygen species) upon light irradiation, more than EGF-Dex-SnCe6(ED) did. It was concluded that, in contrast to EGF-Dex-SnCe6(ED) the photodynamic activity of the EGF-HSA conjugate of SnCe6(ED) on MDA-MB-468 breast adenocarcinoma cells is EGF-specific and more potent than free SnCe6(ED).
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PMID:[Targeting of chlorine E6 by EGF increasing its photodynamic activity in selective ways]. 1100 8

Recombinant human parathyroid hormone-related protein (hPTHrP) (1-139) was expressed using the IMPACT T7 (intein-mediated purification with an affinity chitin-binding tag) system, allowing purification of free recombinant peptide in a single chromatographic step. This system utilizes an intein, which is a protein splicing element from the Saccharomyces cerevisiae VMA1 gene. The intein has been modified so that it undergoes a self-cleavage reaction at its N-terminus at low temperatures in the presence of 1,4-dithiothreitol (DTT). The cDNA encoding hPTHrP (1-139) was cloned into the pTYB1 vector to create an in-frame fusion at the N-terminus of the intein gene. The cDNA for the chitin-binding domain from Bacillus circulans is present at the C-terminus of intein for affinity purification of the three-part fusion protein on a chitin column. The recombinant plasmid was transfected into E. coli ER2566 cells and synthesis of the PTHrP fusion protein was induced with isopropyl-beta-D-thiogalactopyranoside (IPTG). This system produced pure hPTHrP (1-139) and an N-terminally truncated analogue, hPTHrP (27-139), as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blot analysis, N-terminal sequence analysis and mass spectroscopy. hPTHrP (1-139) stimulated cAMP accumulation in ROS 17/2.8 osteoblastic bone cells, whereas hPTHrP (27-139) failed to elicit a response. hPTHrP (1-139) also inhibited the growth of the breast cancer cell line MDA-MB-231; the magnitude of the response was comparable with that of synthetic hPTHrP (1-34) and (1-86). Neutralization of endogenous PTHrP and added hPTHrP (1-139) and N-terminal species with an anti-PTHrP antiserum completely abolished the growth inhibitory effects. These results indicate that the added peptides modulate cell growth by acting at the cell surface. Availability of recombinant hPTHrP (1-139) will allow further study of its biological function, as well as its structure.
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PMID:Single-column purification and bio-characterization of recombinant human parathyroid hormone-related protein (1-139). 1116

We have studied the lipid peroxidation product (malondiadehyde-MDA) levels after thiobarbituric acid reaction, spectrophotometrically and by a high-performance liquid chromatography (HPLC) with UV detection in seminal plasma as well as in the cell fraction. Semen samples were obtained from healthy volunteers and infertile males. Ejaculates were previously classified into studied subgroups according to standard andrological criteria (sperm number, motility, morphology) and defined as: normozoospermia (K), azoospermia (Az), teratozoospermia (T), asthenoteratozoospermia (AT), oligoasthenoteratozoospermia (OAT) and idiopathic infertility (NIF). MDA is a good marker for lipid peroxidation. There were found elevated MDA concentrations (determined by HPLC) in seminal plasma of the all analysed pathological semen samples, especially in patients with OAT. The more pronounced differences between healthy controls and NIF patients were observed in intracellular compartment. The lipid peroxidation of rich in unsaturated fatty acids sperm membranes is considered to be one of the most important effects from ROS-induced cell damage what may lead to persistent infertility.
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PMID:[Peroxidation components of sperm lipid membranes in male infertility]. 1138 94

Renal ischemia-reperfusion injury occurs in many clinical conditions such as hypovolemic shock, thromboembolism, injury and after renal transplantation. Under these conditions, ROS are considered to be the reason for cellular damage. Bioflavonoids have antioxidant and renoprotective properties. We studied the effect of quercetin, a bioflavonoid, on ischemia and reperfusion in rats. The rats (n = 28) were separated into three groups. Group I was the control group. Animals in groups II (IR) and III (IR + Q) underwent 30 min ischemia and 45 min reperfusion, respectively. Rats, in group III, also received 50 mg kg(-1) quercetin before 45 min of reperfusion. The activities of SOD, CAT, GPx, and concentrations of GSH and GSSGR were determined in renal cortex and erythrocytes. Also, the levels of MDA in renal cortex and plasma, and XO in renal cortex were measured in these groups. The renal cortex XO levels in the IR group were higher than that of the control and IR+Q groups (p<0.001). The renal cortex and plasma MDA levels in the IR group were also found to be higher than the control and IR+Q groups (p<0.01, and p<0.001, respectively). However, a decrease in MAD level of the IR+Q group was found in renal cortex and erythrocytes. In addition, SOD, CAT, and GPx activities in renal cortex and erythrocytes of quercetin-treated animals were enhanced compared to animals of the IR group. Furthermore, there were no significant differences in the SOD, CAT, and GPx activities of the control and IR+Q group. A reduction of GSH and GSSGR levels in IR and IR+Q groups was detected but no significant differences were found between these groups. This study stresses that high concentration of ROS leads to renal ischemia and reperfusion, and quercetin reduces the renal injury by preventing the oxidative stress dependent on ischemia and reperfusion. Quercetin may be used in renal transplantation as an antioxidant drug.
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PMID:The effect of quercetin on renal ischemia and reperfusion injury in the rat. 1241 62

The influence of a short-time isobaric hypoxia as well as reoxygenation on markers of oxidative stress (MDA, total SOD, GSH) and on the mRNA expression of the antioxidative enzymes (Cu/Zn-and Mn-SOD, catalase, GSH reductase and GSH peroxidase) has been studied in liver and kidneys of young (6 months) and old (22-25 months) Wistar rats. In livers of old animals, the concentration of GSH, the activity of SOD, and the mRNA expression of the antioxidative enzymes (except Mn-SOD) points to a restricted protection against oxidative stress or a lower production of ROS compared to young animals. Hypoxia resulted in a significant decrease of enzyme gene expression in both age groups. Reoxygenation caused an increase in mRNA of Cu/Zn-SOD and GPX in livers of young and of Mn-SOD in livers of old animals. In kidneys, gene expression of Cu/Zn-SOD, GSH reductase, and GPX was significantly higher in old animals compared to young animals. Whereas hypoxia caused a decrease of gene expression in the livers, it lead to a significant increase of Cu/Zn-SOD, catalase, and GSH reductase mRNA in kidneys of young rats. A reduced gene expression was observed after reoxygenation. In old kidneys, the expression of all enzymes except for catalase progressively declined in the hypoxic and reoxygenation groups. These data show that gene expression of antioxidative enzymes is affected by age and significantly differs between liver and kidney.
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PMID:Effect of age and hypoxia/reoxygenation on mRNA expression of antioxidative enzymes in rat liver and kidneys. 1255 17

Studies have been conducted to examine the feasibility of preventing oxyradical-dependent oxidative stress to mouse lens in culture, using pyruvate as an antioxidant. The extent of oxidative damage to the tissue was assessed by measurement of the status of Na(+)-K(+) ATPase dependent active transport of rubidium 86Rb(+). The tissue levels of adenosine triphosphate (ATP), glutathione (GSH), malonaldehyde (MDA) and catalase were also determined. While the measurement of 86Rb(+) uptake provides an assessment of the integrity of the primary active transport system, measurement of the other components reflects the status of intracellular oxidative stress. ATP measurement also reflected on the overall status of metabolic integrity. Incubation of the lens with xanthine (XA)/xanthine oxidase (XO) system had an adverse effect on all these parameters. Incorporation of pyruvate was strikingly protective. The protective effect of pyruvate is apparently due to its ability to scavenge ROS generated in the medium with the possibility of its action on tissue metabolism as well. The findings are hence considered useful for further studies on the prevention of oxidative stress to tissues by exogenous supplementation with pyruvate, specially the human lens where the biochemistry of its antioxidant mechanisms is similar to the mouse lens, contrary to the rat lens.
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PMID:Oxidative damage to mouse lens in culture. Protective effect of pyruvate. 1278 21

Quercetin (QU) displays antioxidant and cell protective effects in most cell culture models, yet in some studies it is reported that QU shows prooxidant and cytotoxic effects. In order to explore the real role of ROS in QU's cytotoxicity, the cytotoxicity of QU and/or H2O2, as indicated by the proliferation and viability of HL-60 cells, was examined in this study. Both H2O2 and QU dose-dependently induced cell proliferation arrest and cell death. The cytotoxicity of QU could be diminished by the supplement of H2O2 in the culture medium, at the same time, the addition of QU also significantly attenuated H2O2- caused cytotoxicity. These results indicated that certain amounts of ROS are critical for the proliferation and viability of HL-60 cells, QU scavenged the necessary ROS, and hence led to the proliferation arrest and cell death; on the contrary, the excessive ROS, such as H2O2, are obviously harmful to HL-60 cells, under these conditions, QU protected cells through diminishing the excessive ROS in vivo. Thus QU exerted its effects on cells, including its cytotoxic and protective effects, mainly through its antioxidant activity. The malondialdehyde (MDA, an index of ROS level) assay further confirmed this conclusion, as the effects of QU, H2O2, or their combination on HL-60 cells were closely related with the variation of MDA amounts in vivo.
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PMID:Coadjustment of quercetin and hydrogen peroxide: the role of ROS in the cytotoxicity of quercetin. 1502 87


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