Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P08758 (annexin V)
 9,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure of renal medullary cells to elevated extracellular NaCl concentrations is associated with increased heat shock protein 72 (HSP72) expression and improved resistance to subsequent exposure to a high urea concentration (600 mM). To establish a causal relationship between HSP72 expression and protection against high urea concentrations, HSP72 was inducibly overexpressed in Madin-Darby canine kidney (MDCK) cells, in the absence of hypertonic stress before urea exposure. For this purpose, the human stress-inducible HSP72 gene was cloned downstream from a dexamethasone (DEX)-inducible promoter in the eukaryotic expression vector pLKneo. This construct allowed robust induction of HSP72 by exposure of stably transfected MDCK cells (MDCK-LK72) to 0.1 microM DEX. Increased HSP72 abundance significantly improved survival rates after 24-h exposure of the cells to medium containing 600 mM urea (14 versus 43%). In mock-transfected or wild-type cells, DEX had no significant effect on HSP72 abundance or urea resistance. In accordance with those findings, lactate dehydrogenase activity in the supernatant was significantly reduced, compared with appropriate control samples, only in MDCK-LK72 cells overexpressing HSP72. Labeling with annexin V-FITC and propidium iodide, followed by flow cytometry, revealed that overexpression of HSP72 was associated with a reduction in the number of apoptotic-lysed cells, a concomitant retardation of apoptosis, and an increase in the number of viable cells. These data support the view that HSP72, which is very abundant in the renal inner medulla, is an important component of the defense mechanism of medullary cells against extreme concentrations of urea.
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PMID:Regulated overexpression of heat shock protein 72 protects Madin-Darby canine kidney cells from the detrimental effects of high urea concentrations. 1172 24

We have reported previously that sigma-2 receptors are expressed in high densities in a variety of tumor cell types (B. J. Vilner et al., Cancer Res., 55: 408-413, 1995) and that various sigma ligands have cytotoxic effects (B. J. Vilner et al., J. Neurosci., 15: 117-134, 1995). Other investigators have demonstrated increased expression of sigma-2 receptors in rapidly proliferating tumors (R. H. Mach et al., Cancer Res., 57: 156-161, 1997) and the ability of some sigma ligands to inhibit proliferation (P. J. Brent and G. T. Pang, Eur. J. Pharmacol., 278: 151-160, 1995). We demonstrate here the ability of sigma-2 receptor agonists to induce cell death by a mechanism consistent with apoptosis. In breast tumor cell lines that are sensitive (MCF-7) and resistant (MCF-7/Adr-, T47D, and SKBr3) to antineoplastic agents, incubation with the sigma-2 subtype-selective agonists CB-64D and CB-184 produced dose-dependent cytotoxicity (measured by lactate dehydrogenase release into medium). The EC(50) for this response was similar across cell lines, irrespective of p53 genotype and drug-resistance phenotype. CB-64D and the subtype nonselective sigma-2 agonists haloperidol and reduced haloperidol induced terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining in MCF-7 and T47D cells, indicating that cell death occurs via apoptosis. Apoptosis was also indicated by increases in Annexin V binding caused by CB-64D. In MCF-7 cells, cytotoxicity and Annexin V binding induced by the antineoplastics doxorubicin and actinomycin D was partially or completely abrogated by certain specific and general inhibitors of caspases. In contrast, caspase inhibitors had no effect on sigma-2 receptor-mediated (CB-64D and CB-184) cytotoxicity or Annexin V binding. Marked potentiation of cytotoxicity was observed when a subtoxic dose of CB-184 was combined with doxorubicin or actinomycin D, both in drug-sensitive (MCF-7) and drug-resistant (MCF-7/Adr-) cell lines. Haloperidol potentiated doxorubicin only in drug-resistant cells. These findings suggest the involvement of a novel p53- and caspase-independent apoptotic pathway used by sigma-2 receptors, which is distinct from mechanisms used by some DNA-damaging, antineoplastic agents and other apoptotic stimuli. These observations further suggest that sigma-2 receptors may be targets that can be therapeutically exploited in the treatment of both drug-sensitive and drug-resistant metastatic tumors.
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PMID:Sigma-2 receptor agonists activate a novel apoptotic pathway and potentiate antineoplastic drugs in breast tumor cell lines. 1178 94

A wide spectrum of anti-cancer activity of genistein and beta-lapachone in various tumors has been reported in single treatments. In this study the combined effects of genistein and beta-lapachone on the chemosensitivity of LNCaP and PC3 human prostate cancer cells was determined in vitro, using 3-[4,5-dimethylthiazol-2-yl]-2-,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) to study treatment-induced growth inhibition and cytotoxicity and, annexin V-fluoresceine (FI) and terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-propidium iodide (PI) assays to determine potential treatment-induced apoptosis and/or necrosis. The results showed: i) that both PC3 and LNCaP are sensitive to single and combination treatments regardless of hormone sensitivity status, ii) that treatment induced dual death pathways (apoptosis and necrosis) in both cell types, iii) that growth inhibition in both cell types correlated positively with cell death via apoptosis at lower drug concentrations and necrosis at higher concentrations, iv) that combination of genistein and beta-lapachone had synergistic inhibitory effects on growth and proliferation in both cell types. The synergistic inhibitory effect was correlated positively with treatment-induced cell death via apoptosis and necrosis. The overall results indicate that combination treatments with beta-lapachone and genistein are more potent in killing both PC3 and LNCaP cancer cells than treatment with either genistein or beta-lapachone alone. beta-lapachone acts at the G1 and S phase checkpoints in the cell cycle, while genistein induces cell cycle arrest at the G2-M stage. The current results are therefore in agreement with the hypothesis that drug combinations that target cell cycles at different critical checkpoints would be more effective in causing cell death. This result provides a rationale for in vivo studies to determine whether beta-lapachone-genistein combination will provide effective chemotherapy for prostate cancer, regardless of the tumor sensitivity to hormone.
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PMID:Chemosensitivity of human prostate cancer cells PC3 and LNCaP to genistein isoflavone and beta-lapachone. 1200 Jan 45

Increased cell volume, accumulation of lipid droplets in the cytoplasm, and nuclear degeneration are phenomena indicating terminal differentiation of human sebocytes followed by holocrine secretion and cell death. The molecular pathways of natural and induced sebocyte elimination are still unknown, however. In this study, SZ95 sebocytes were found to exhibit DNA fragmentation after a 6 h culture followed by increased lactate dehydrogenase release after 24 h, indicating cell damage. With the help of morphologic studies and using Oil Red detection of cellular lipids, cell enlargement, accumulation of lipid droplets in the cytoplasm, and nuclear fragmentation could be observed under treatment with arachidonic acid. Staurosporine, a potent inhibitor of phospholipid Ca2+-dependent protein kinase, increased externalized phosphatidylserine levels on SZ95 sebocytes, detected by annexin V/propidium iodide flow cytometry, as early as after 1 h, whereas dose-dependent reduction of bcl-2 mRNA and protein expression, enhanced DNA fragmentation, and increased caspase 3 levels, detected by caspase 3 inhibitor/propidium iodide flow cytometry, were found after 6 h of treatment. SZ95 sebocyte death was detected as early as after 6 h of SZ95 sebocyte treatment with high staurosporine concentrations (10(-6)-10(-5) M). 5Alpha-dihydrotestosterone (10(-8)-10(-5) M) did not affect externalized phosphatidylserine levels and DNA fragmentation in SZ95 sebocytes but slightly decreased lactate dehydrogenase cell release. Neither acitretin nor 13-cis retinoic acid (10(-8)-10(-5) M) affected externalized phosphatidylserine levels, DNA fragmentation, and lactate dehydrogenase cell release, despite the increased caspase 3 levels under treatment with 13-cis retinoic acid. The combined staurosporine and 13-cis retinoic acid treatment enhanced DNA fragmentation in SZ95 sebocytes to the same magnitude as in cells only treated with staurosporine. In conclusion, SZ95 sebocytes in vitro undergo apoptosis, which can be enhanced by the terminal differentiation inductor arachidonic acid or by staurosporine and leads to cell death. 5Alpha-dihydrotestosterone inhibits SZ95 sebocyte death without involving apoptotic pathways, and retinoids did not affect the programmed death of human sebocytes. The latter result fits well with the currently reported inability of normal skin cells to undergo apoptosis after treatment with retinoids, in contrast to their malignant counterparts.
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PMID:Differentiation and apoptosis in human immortalized sebocytes. 1254 19

In this study, we have synthesized several compounds and examined their cytotoxic effects on human non-small cell lung cancer A549 cells. We found that GO-13 ((E,E)-2,5-bis[4-(3-dimethyl-aminopropoxy)styryl]-1,3,4-thiadiazole) is the most effective one by the MTT assay. Furthermore, the GO-13-induced apoptotic reaction was identified based on several criteria, such as negative release reaction of lactate dehydrogenase and positive labeling of annexin V and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) techniques. GO-13 induced the apoptosis in A549 cells in a concentration- and time-dependent manner. The data demonstrate that the regulations of p38 mitogen-activated protein kinase and protein kinase C was not involved in the GO-13-mediated mechanism. However, GO-13 significantly induced a down-regulation of Bcl-X(L) expression in a short-term treatment (less than 3hr), whereas stimulated up-regulation of Bax expression in a long-term treatment (24hr) indicating their involvement in GO-13 action. GO-13-mediated apoptosis is also positively correlated with the increase in caspase-3 activity. Worth noting is the fact that GO-13 did not modify the phosphorylation level of Akt/protein kinase B (PKB) until a 24-hr exposure was carried out indicating that the inhibition of Akt/PKB activation was involved in the late-phase apoptosis. Besides the anticancer activity, GO-13 also showed equivalent anti-angiogenic activity in the nude mice angiogenesis model. In summary, we conclude that GO-13 is the most effective anticancer compound in our screening tests. It induced the early-phase apoptosis in A549 cells via the Bcl-X(L) down-regulation, and that of the late-phase through up-regulation of Bax expression as well as inhibition of Akt/PKB activation.
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PMID:Investigation of anticancer mechanism of thiadiazole-based compound in human non-small cell lung cancer A549 cells. 1281 71

Mercury is a highly toxic heavy metal; exposure to mercury in humans and animals causes damage in several organs or systems including the immune system. To characterize the toxicity of mercury in the immune cells, the cytotoxic effects of inorganic mercury were studied in two distinct lymphoma lines, the murine T lymphoma (EL4) and B lymphoma (A20) cells. Mercury concentration-dependently decreased cell viability, membrane integrity, and proliferation in both EL4 and A20 cells. Mercury increased the reactive oxygen species (ROS) production in both EL4 and A20 cells, and pretreatment with antioxidants reversed mercury-induced ROS generation. Pretreatment of cells with antioxidants N-acetylcysteine (NAC) and silymarin decreased mercury-induced lactate dehydrogenase (LDH) release in both types of cells; however, Ca(2+) channel blocker lanthanum (La(2+)) decreased it only in A20 cells. The mode of cytotoxicity was a mixture of both apoptosis and necrosis. Mercury-induced apoptosis and necrosis in the two cell lines were indicated by staining with Hoechst 33258, propidium iodide, and co-staining with annexin V and propidium iodide. Both mercury-induced apoptosis and necrosis were attenuated by antioxidants. Mercury increased gene expression of IL-4 and TNFalpha in EL4 cells; these cytokines were not expressed in A20 cells. Data suggested different pathways of mercury-induced cytotoxicity in T and B lymphoma cells and involvement of ROS, Ca(2+) homeostasis, and inflammatory cytokine gene expression.
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PMID:Cytotoxicity of inorganic mercury in murine T and B lymphoma cell lines: involvement of reactive oxygen species, Ca(2+) homeostasis, and cytokine gene expression. 1284 21

The cytotoxicity caused by the debris resulting from wear of prostheses can produce major damage to tissues around the implant. We have compared particle internalization by macrophages and fibroblasts in vitro and analyzed cell death. J774.2 macrophages and L929 fibroblasts were incubated with 0.43 and 2.81 microm alumina particles or 0.45 and 3.53 microm polystyrene (PS) beads. Incubation of J774.2 cells with alumina particles of both sizes and 0.5 and 1.0 mg/ml PS beads significantly decreased cell numbers in a particle concentration-dependent manner. L929 cells were not affected by lower concentrations of 0.43 microm alumina particles (which aggregate at high concentrations) and they internalized 0.45 microm PS beads without any decrease in cell numbers. Particles were more cytotoxic for macrophages than for fibroblasts. Particles caused the size of both types of cells to increase in correlation with cytotoxicity. Trypan blue exclusion and lactate dehydrogenase release showed cell membrane leakage for both types of cells incubated with PS beads for 24 h. Apoptosis was assessed by annexin V-FITC, propidium iodide staining and assay of caspase 3 activity. Macrophage death appeared to depend on both necrosis, caused mainly by 3.53 microm PS beads, and apoptosis, mainly due to 0.45 microm PS beads. The release of the inflammatory cytokine IL-6 appears to be nonlinearly correlated with cytotoxicity. Thus, the size of the internalized particles affects macrophages and fibroblasts differently, and the increase in cell size can be used as a preliminary criterion of particle cytotoxicity in vitro.
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PMID:Comparative particle-induced cytotoxicity toward macrophages and fibroblasts. 1294 43

Rough mutants of Brucella spp. are attenuated for survival in animal models. However, conflicting in vitro evidence has been obtained concerning the intracellular survival of rough mutants. Transposon-derived rough mutants isolated in our laboratory were previously shown to exhibit small but significant reductions in intracellular survival in a 12-h in vitro assay. Several recent publications report that rough mutants exhibited increased macrophage uptake relative to their smooth parental strains, and a reduction in numbers at the end of the assay has been interpreted as intracellular killing. In an effort to explore the role of O antigen in the interaction between Brucella abortus and macrophages, we have monitored the uptake of rough mutants and survival in vitro by using the murine macrophage cell line J774.A1. The results confirm a 10- to 20-fold-increased uptake of rough mutants over that of smooth organisms under standard conditions. Recovery of the rough mutants persisted up to 8 h postinfection, but at the point when intracellular replication of the smooth organisms was observed, the number of rough organisms recovered declined. Fluorescence microscopy revealed the intracellular multiplication of both smooth and rough organisms, and assays performed in the absence of antibiotic confirmed the replication of the rough organisms. Examination by phase-contrast microscopy revealed the lytic death of macrophages infected with the rough mutants, which was confirmed by the release of lactate dehydrogenase (LDH) from the cell cytoplasm. Thus, the decline in the number of rough organisms was the result of the lysis of macrophages and not from intracellular killing. The cytopathic effect is characterized as necrotic rather than apoptotic cell death based on early LDH release, annexin V and propidium iodide staining, morphological changes of infected cells and nuclei, and glycine protection. The cytopathic effect was observed with macrophages at multiplicities of infection (MOIs) of as low as 20 and was not observed with epithelial cells at MOIs of as high as 2000. These findings suggest a role for O antigen during the early stages of host-agent interaction that is essential in establishing an intracellular niche that maintains and supports persistent intracellular infection resulting in disease.
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PMID:Brucella abortus rough mutants are cytopathic for macrophages in culture. 1468 25

Tomatine adjuvant, consisting of tomatine, n-octyl-beta-d-glucopyranoside (OGP), phosphatidylethanolamine and cholesterol is unique in that when combined with soluble protein antigen it elicits a cytotoxic T lymphocyte (CTL) response in immunized animals. The mechanisms underlying this property are unknown. In an attempt to understand how tomatine activates cellular immunity, we examined its potential to induce apoptosis. Thus in the present study, cell death of EL4 thymoma cells induced by whole adjuvant and the surface-active components in the formulation was examined. Cytotoxicity was monitored using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and lactate dehydrogenase release assays, apoptosis and necrosis were quantified by flow cytometry using Annexin V and propidium iodide staining, and morphology was examined by Hoechst 33342 staining. Flow cytometric analysis demonstrated the appearance of the sub-G1 phase in cells treated with these agents and Annexin V/PI staining showed that all three agents induced both apoptosis and necrosis in EL4 cells in a concentration-dependent manner. Tomatine was effective at much lower concentrations than OGP, suggesting that the majority of the effect of whole adjuvant could be attributed to this component. Microscopic examination of EL4 cells after treatment with these agents revealed morphological features of apoptosis, including chromatin condensation and DNA fragmentation. Pretreatment with zVAD-fmk did not block cell death induced by these agents, showing that tomatine adjuvant-induced EL4 cell apoptosis is caspase-independent.
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PMID:The apoptotic and necrotic effects of tomatine adjuvant. 1514 91

The effect of ascorbate on cell death was examined in Jurkat cells (human T-cell leukemia) by incubation with dehydroascorbate (DHA), which is rapidly taken up by cells and efficiently reduced to ascorbate. Apoptosis was evaluated by caspase-3 activity in cell extracts and flow cytometry of annexin V-labeled cells. In parallel, necrosis was estimated by the release of lactate dehydrogenase. Minor effects on cell death were observed when Jurkat cells were incubated with either DHA alone (100-1,000 microM) or a single dose of 10 microM H(2)O(2). However, pre-incubation with DHA followed by exposure to H(2)O(2) clearly stimulated both apoptosis and necrosis. In complete contrast, pre-incubation of cells with DHA significantly inhibited apoptosis, but did not affect necrosis, induced by the topoisomerase I inhibitor camptothecin. Our results indicate that intracellular ascorbate can modulate cell death in a manner which depends upon the nature of the apoptotic stimulus, which in turn has critical implications regarding the mechanism and potential application of ascorbate in cancer therapy.
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PMID:Ascorbate modulation of H(2)O(2) and camptothecin-induced cell death in Jurkat cells. 1519 88


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