Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the mechanism of 17beta-estradiol (estrogen)-mediated inhibition of apoptosis in C6 (rat glioma) cells following exposure to hydrogen peroxide (H(2)O(2)). Cells were preincubated with 4 microM estrogen for 2 h and then exposed to 100 microM H(2)O(2) for 24 h. Exposure to H(2)O(2) caused significant increases in intracellular calcium (Ca(2+)), as determined by fura-2, which was attenuated by preincubation with estrogen. H(2)O(2) and ionomycin caused cell death in a dose-dependent manner, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Preincubation with estrogen restored viability in cells exposed to H(2)O(2) but not in cells exposed to ionomycin. Western blot analysis showed an increase in Bax/Bcl-2 ratio, calpain activity, and caspase-3 activity following treatment with H(2)O(2), and estrogen pretreatment decreased levels of all three. Cell morphology, as evaluated by Wright staining, indicated apoptosis in cells treated with H(2)O(2), and pretreatment with estrogen reduced apoptosis. Results from MTT and Wright staining were further supported by the terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP Nick End Labeling (TUNEL) assay. These results indicate a role for estrogen in preventing apoptosis in C6 glial cells exposed to H(2)O(2). Our results suggest that estrogen may have a protective role in minimizing glial cell apoptosis in neurological diseases such as demyelinating disease or central nervous system trauma.
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PMID:Estrogen attenuates oxidative stress-induced apoptosis in C6 glial cells. 1270 34

The epidermal growth factor receptor (EGFR) is an important novel target for anticancer therapy. In this study, we examined the molecular mechanisms that underlie the antitumor effects of the anti-EGFR monoclonal antibody C225 (Cetuximab) and the selective EGFR tyrosine kinase inhibitor ZD1839 (Iressa; AstraZeneca) in non-small cell lung cancer (NSCLC) cell lines. Cell growth, assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, was inhibited at low concentrations of ZD1839 and C225 in control A431 cells, whereas the NSCLC cell lines were comparatively more resistant. In A431 cells, but not in the NSCLC cells, ZD1839 treatment resulted in a modest increase in DNA fragmentation, the externalization of phosphatidyl serine, and the activation of caspase-3, known markers of apoptotic cell death. However, poly(ADP-ribose) polymerase cleavage was not detected, and caspase inhibition by carbobenzoxy-Val-Ala-Asp-fluoromethyl ketone partially reduced ZD1839-generated DNA fragmentation. Overexpression of the antiapoptotic protein Bcl-2 in A431 cells suppressed the cytotoxicity upon anti-EGFR treatment. These results thus demonstrate that the toxic effect of ZD1839 in A431 cells is caused by a form of cell death that involves a mitochondrial step and is, at least in part, dependent on caspase activation. EGFR expression levels showed no significant correlation with sensitivity to ZD1839 and C225. Evaluation of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase and phosphatidylinositol 3'-kinase/Akt pathways showed considerable inhibition of these pathways by ZD1839 and C225 in A431 cells, whereas one or both of these pathways remained active upon anti-EGFR treatment in NSCLC cells. In addition, treatment with specific inhibitors of mitogen-activated protein kinase kinase or phosphatidylinositol 3'-kinase resulted in a smaller effect on proliferation than simultaneous treatment with both inhibitors, whereas induction of apoptosis was observed only when both pathways were blocked. Together, these data suggest that persistent activity of either of these signaling pathways is involved in the lack of sensitivity of NSCLC cell lines to EGFR inhibitors.
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PMID:Response to epidermal growth factor receptor inhibitors in non-small cell lung cancer cells: limited antiproliferative effects and absence of apoptosis associated with persistent activity of extracellular signal-regulated kinase or Akt kinase pathways. 1279 1

Sanguinarine, derived from the root of Sanguinaria canadensis and other poppy fumaria species, possesses strong antimicrobial, anti-inflammatory, and antioxidant properties. We earlier showed that sanguinarine kills human epidermoid carcinoma A431 cells via an induction of apoptosis [N. Ahmad et al., Clin. Cancer Res., 6: 1524-1528, 2000]. In this study, using immortalized human keratinocytes (HaCaT cells), we provide information about mechanism of the antiproliferative effect of sanguinarine. Sanguinarine [0.1 (M-2 (M)] treatment to HaCaT cells was found to inhibit in a dose-dependent manner the cell proliferation and induce apoptosis, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ELISA, respectively. Sanguinarine treatment also resulted in a significant cleavage of poly(ADP-ribose) polymerase in HaCaT cells. Because mitochondrial pathway is critical for the regulation of apoptosis, we studied the involvement and regulation of mitochondrial events in sanguinarine-mediated apoptosis of HaCaT cells. As shown by the immunoblot analysis, our data clearly demonstrated that sanguinarine treatment to HaCaT cells resulted in a dose-dependent (a) increase in the level of Bax with a concomitant decrease in Bcl-2 levels and (b) increase in Bax/Bcl-2 ratio. Sanguinarine also resulted in significant increases in the proapoptotic members of Bcl-2 family proteins, i.e., Bak and Bid. This was accompanied by increase in (a) protein expression of cytochrome c and apoptotic protease-activating factor-1 and (b) activity and protein expression of caspase-3, caspase-7, caspase-8, and caspase-9. Taken together, our data showed the involvement of mitochondrial pathway and Bcl-2 family proteins during sanguinarine-mediated apoptosis of immortalized keratinocytes. We suggest that sanguinarine could be developed as a drug for the management of hyperproliferative skin disorders, including skin cancer.
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PMID:Activation of prodeath Bcl-2 family proteins and mitochondrial apoptosis pathway by sanguinarine in immortalized human HaCaT keratinocytes. 1291 70

Malignant tumours contain zones of chronic or acute hypoxia, which influence their prognosis and progression. The goal of our study was to understand the role of hypoxia in radio-resistance in a squamous cell carcinoma cell line of the head and neck (KB-3-1 cells). Cell growth was evaluated by Trypan blue exclusion under chronic hypoxia (3-5% O2) for 4 weeks or under normal conditions (21% O2). Cells were then gamma-irradiated either by X-ray (2-6 Gy) or UV-C radiation (0.001-10 J/cm(2)). Apoptosis was estimated by double staining with orange acridine and ethydium bromide and fluorescence microscopy. DNA content was estimated by FACS analysis. Expression of Bax, Bcl-2 and P53 was assessed by immunofluorescence and Western blotting. ROS production was measured by dichlorofluorescein fluorescence. Cell growth depends on oxygen tension. It decreased by 42 and 70% at 5 and 3% O2 compared to control with a significant cell cycle arrest rather than increased mortality. Hypoxic cells are more radio-resistant (x2.5) than normoxic cells. Under chronic hypoxia, Bcl-2 increased considerably in cells compared to control, while Bax and P53 did not change. After irradiation, in hypoxic cells very weak expression of the pro-apoptotic Bax protein and no translocation of Bax to the mitochondria were observed. In addition, irradiation of control KB-3-1 cells demonstrated a large increase in ROS production (x2) compared to cells irradiated identically under hypoxia. In conclusion, chronic hypoxia: i) seems to slow-down cell growth of KB-3-1 cells without inducing apoptosis, ii) induces Bcl-2 overexpression and prevents radiation-induced apoptosis by inhibiting ROS production and altering Bax subcellular redistribution and conformational changes.
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PMID:Chronic hypoxia protects against gamma-irradiation-induced apoptosis by inducing bcl-2 up-regulation and inhibiting mitochondrial translocation and conformational change of bax protein. 1296 83

Loss of cardiomyocytes by apoptosis is proposed to cause heart failure. Angiotensin II (ANG II), an important neurohormonal factor during heart failure, can induce cardiomyocyte apoptosis. Inasmuch as hexarelin has been reported to have protective effects in this process, we examined whether hexarelin can prevent cardiomyocytes from ANG II-induced cell death. Cultured cardiomyocytes from neonatal rats were stimulated with ANG II. Apoptosis was evaluated using fluorescence microscopy, TdT-mediated dUTP nick-end labeling (TUNEL) method, flow cytometry, DNA laddering, and analysis of cell viability by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). It was found that incubation with 0.1 micromol/l ANG II for 48 h increased cardiomyocyte apoptosis. Administration of 0.1 micromol/l hexarelin significantly decreased this ANG II-induced apoptosis and DNA fragmentation and increased myocyte viability. To further investigate the underlying mechanisms, caspase-3 activity assay and mRNA expression of Bax, Bcl-2, and growth hormone secretagogue receptor (GHS-R; the supposed hexarelin binding site) were examined. GHS-R mRNA was abundantly expressed in cardiomyocytes and was upregulated after administration of hexarelin. These results suggest that hexarelin abates cardiomyocytes from ANG II-induced apoptosis possibly via inhibiting the increased caspase-3 activity and Bax expression induced by ANG II and by increasing the expression of Bcl-2, which is depressed by ANG II. Whether the upregulated expression of GHS-R induced by hexarelin is associated with this antiapoptotic effect deserves further investigation.
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PMID:Hexarelin protects rat cardiomyocytes from angiotensin II-induced apoptosis in vitro. 1461 77

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in many human cancer cells but not in normal cells. Thyroid cancer cells, however, appear to be relatively resistant to TRAIL-induced apoptosis. We therefore investigated the effect of chemotherapy on TRAIL-induced apoptosis in thyroid cancer cells. We used six thyroid cancer cell lines: TPC-1, FTC-133, FTC-236, FTC-238, XTC-1, and ARO82-1. We used flow cytometry to measure apoptosis, dimethyl-thiazol-diphenyltetrazolium bromide (MTT) assay to measure antiproliferation effects and Western blot to determine the expression of Bcl family proteins. Troglitazone, paclitaxel, geldanamycin, and cycloheximide were used for pretreatment. We used the Student's t test and analysis of variance (ANOVA) for statistical analysis. All thyroid cancer cell lines, except the TPC-1 cell line, were resistant to TRAIL, and growth inhibition was less than 20% at concentration of 800 ng/mL of TRAIL. In both TPC-1 (TRAIL-sensitive) and FTC-133 (TRAIL-resistant) thyroid cancer cell lines, pretreatment with troglitazone, cycloheximide, and paclitaxel enhanced TRAIL-induced cell death significantly but pretreatment with geldanamycin did not. There were no significant changes in Bcl-2, Bcl-xl, and Bax protein expression after troglitazone treatment. In conclusion, TRAIL in combination with troglitazone, paclitaxel, and cycloheximide induces apoptosis in thyroid cancer cells at suboptimal concentrations that cannot be achieved using TRAIL alone.
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PMID:Modulation of tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by chemotherapy in thyroid cancer cell lines. 1475 Oct 30

Although apoptosis has been considered the typical mechanism for physiological cell death, presently alternative mechanisms need to be considered. We previously showed that fibroblast growth factor-2 (FGF2) could act as a survival factor for neural precursor cells. To study the death mechanism activated by the absence of this growth factor, we followed the changes in cell morphology and determined cell viability by staining with several dyes after FGF2 removal from mesencephalic neural-progenitor-cell cultures. The changes observed did not correspond to those associated with apoptosis. After 48 h in the absence of FGF2, cells began to develop vacuoles in their cytoplasm, a phenotype that became very obvious 3-5 days later. Double-membrane vacuoles containing cell debris were observed. Vacuolated cells did not stain with either ethidium bromide or trypan Blue, and did not show chromatin condensations. Nonetheless, during the course of culture, vacuolated cells formed aggregates with highly condensed chromatin and detached from the plate. Neural progenitor cells grown in the presence of FGF2 did not display any of those characteristics. The vacuolated phenotype could be reversed by the addition of FGF2. Typical autophagy inhibitors such as 3-MA and LY294002 inhibited vacuole development, whereas a broad-spectrum caspase inhibitor did not. Interestingly, Bcl-2 overexpression retarded vacuole development. In conclusion, we identified a death autophagy-like mechanism activated by the lack of a specific survival factor that can be inhibited by Bcl2. We propose that anti-apoptotic Bcl2 family members are key molecules controlling death activation independently of the cell degeneration mechanism used.
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PMID:Growth factor deprivation induces an alternative non-apoptotic death mechanism that is inhibited by Bcl2 in cells derived from neural precursor cells. 1497 82

A potent inhibitor of serine/threonine kinases, staurosporine exerts antiproliferative and apoptotic effects in many cancer cells, although the exact mechanism of its action is still unclear. This study examines the effects of staurosporine on Chang liver cells, an immortalized non-tumor cell line, in comparison with those caused in HuH-6 and HepG2 cells, two human hepatoma cell lines. Our results provide evidence that staurosporine promotes apoptosis in Chang liver cells as observed by flow cytometric analysis and acridine orange/ethidium bromide staining. The effect appeared already after 8 h of treatment and increased with treatment time and dose. After 48 h of exposure to 200 nM staurosporine clear apoptotic signs were observed in about 50% of the cells. Western blotting analysis showed that in Chang liver cells staurosporine induced a marked decrease in the levels of the antiapoptotic factors Bcl-2 (-75%) and Bcl-XL (-50%). Staurosporine also caused loss of mitochondrial transmembrane potential, release of cytochrome c from mitochondria and activation of caspase-3. The involvement of caspases in staurosporine-induced cell death was also suggested by the observation that the addition of z-VAD-fmk, a general inhibitor of caspases, suppressed apoptosis. In HuH-6 and HepG2 cells treatment with staurosporine induced the arrest of cells in G2/M phase of cell cycle. This effect was not modified by z-VAD-fmk and was not accompanied by the appearance of biochemical signs of apoptosis. We conclude that staurosporine induced apoptosis in Chang liver cells by a mitochondria-caspase-dependent pathway which was closely correlated with a decrease in Bcl-2 and Bcl-XL levels, while in HuH-6 and HepG2 hepatoma cells the drug caused only an antiproliferative effect.
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PMID:Staurosporine-induced apoptosis in Chang liver cells is associated with down-regulation of Bcl-2 and Bcl-XL. 1501 Aug 57

In this study, we analyzed the effect of Bcl-2 overexpression, an important anti-apoptotic protein, by using two hypothalamic cell lines, GT1-7puro or GT1-7bcl-2. 3-Nitropropionic acid (3-NP) mediated a dose-dependent decrease in cell viability in GT1-7puro cells, as determined by following the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reduction, which was significantly prevented in GT1-7bcl-2 cells. In addition, activation of caspases-2, -3, and -6 induced by 3-NP was prevented by Bcl-2 overexpression. The data suggest that irreversible inhibition of mitochondrial complex II induces apoptotic features of cell death in a process prevented by Bcl-2.
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PMID:Bcl-2 prevents loss of cell viability and caspase activation induced by 3-nitropropionic acid in GT1-7 cells. 1503 10

Dopamine receptor agonists are protective in different models of neurodegeneration by both receptor-dependent and -independent mechanisms. We used SH-SY5Y cells, differentiated into neuron-like type, to evaluate if cabergoline, a dopamine D2 receptor agonist endowed with anti-oxidant activity, protects the cells against ischemia (oxygen-glucose deprivation model). Cabergoline protected the cells from ischemia-induced cell death in a concentration-dependent manner (EC(50)=1.2 microM), as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release, and fluorescein diacetate-propidium iodide staining. This effect, observed even when the drug was added after oxygen-glucose deprivation, was not mediated by either dopamine D2 receptor activation or anti-apoptotic Bcl-2 protein over-expression (Western blotting analysis), but was linked to a reduction in cellular free radical loading (2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining) and membrane lipid peroxidation (thiobarbituric acid-reacting test). In conclusion, cabergoline protects in vitro neurons against ischemia-induced cell death, suggesting its possible use in the therapy of other neurodegenerative diseases in addition to Parkinson's disease.
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PMID:Cabergoline protects SH-SY5Y neuronal cells in an in vitro model of ischemia. 1508 38


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