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)

Bcl-2 family proteins play a crucial role in the cytoprotective action of insulin-like growth factor-I (IGF-I) by regulating cell death signaling at the mitochondrial level. The present study examined the effect of IGF-I on the expression of Bcl-2 family proteins in the rat heart mitochondria in relation to myocardial protection against ischemia-reperfusion injury. Systemic IGF-I (1 mg) treatment in the rat increased Bcl-xL and attenuated Bax 12-24 h later in the heart mitochondria fraction. Permeability transition and cytochrome c release occurred in a Ca(2+) concentration-dependent manner in the vehicle-treated mitochondria. This was significantly inhibited by the IGF-I-pretreatment. Moreover, ATP synthesis was significantly greater in the IGF-I-pretreated mitochondria. IGF-I pretreatment 24 h before 25 min of global ischemia in the isolated rat heart model significantly improved recovery of isovolumic left ventricular function and inhibited creatine kinase release during reperfusion. This was associated with a significantly less number of terminal transferase labeling-positive myocytes and nonmyocytes 2 h after reperfusion. These results suggest that IGF-1 differentially regulates Bcl-xL and Bax in heart mitochondria, which may be causally related to myocardial protection against ischemia-reperfusion injury.
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PMID:IGF-I differentially regulates Bcl-xL and Bax and confers myocardial protection in the rat heart. 1117 63

The role of endogenous NO on cell survival was investigated in human melanoma cells and melanocytes. Inducible NO synthase (iNOS) was always expressed in a panel of melanoma cell lines from metastatic lesions and in normal adult melanocytes. iNOS was also detected by immunohistochemistry in melanoma cells from metastases. Release of NO by tumor cells and melanocytes was inhibited by a specific iNOS inhibitor, aminoguanidine (AMG). Inhibition of endogenous NO synthesis did not affect cell cycle progression of melanoma cells but led to cell death by apoptosis, as indicated by Annexin V/propidium iodide and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling assays. By contrast, iNOS inhibition by AMG did not promote apoptosis in normal adult melanocytes. A mitochondrial pathway was involved in melanoma apop tosis, as indicated by altered mitochondrial membrane potential (delta psi(m)) and down-regulation of Bcl-2 protein level after iNOS inhibition. AMG treatment triggered release of caspase-1, enzymatic activation of caspase-3, and degradation of poly(ADP-ribose) polymerase, one of the main caspase-3 substrates. Melanoma cell apoptosis induced by iNOS inhibition was completely blocked by peptide inhibitors of caspase-1 and caspase-3 (Ac-DEVD-CHO and AC-YVAD-CHO) or by an exogenous NO donor, sodium nitroprusside, or by addition of serum. Finally, comparison of control and AMG-treated melanoma cells by pathway-specific gene array analysis indicated that inhibition of NO synthesis led, before induction of apoptosis, to up-regulation of mRNA levels of genes involved in the apoptosis pathway such as Bax, caspase-1, caspase-3, caspase-6, gadd45beta, mdm2, and TRAIL. Taken together, these results indicate that melanoma cell survival is regulated by endogenous NO resulting from iNOS activity.
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PMID:Antiapoptotic role of endogenous nitric oxide in human melanoma cells. 1119 80

Interactions between the purine analogue 2-fluoroadenine 9-beta-D-arabinofuranoside (F-ara-A) and the kinase inhibitor UCN-01 have been examined in human leukemia cells (U937 and HL-60) with respect to induction of mitochondrial damage, caspase activation, apoptosis, and loss of clonogenic survival. Simultaneous or subsequent exposure of F-ara-A-treated cells (2 microM) to UCN-01 (100 nM) resulted in a marked potentiation of apoptosis, manifested by loss of mitochondrial membrane potential (delta psi(m)), cleavage/activation of procaspase-9 and procaspase-3, DNA fragmentation, and degradation of poly-ADP(ribosyl) polymerase. Coadministration of UCN-01 with F-ara-A was also associated with diminished phosphorylation of the cdc25 phosphatase. In contrast, exposure of cells to the sequence UCN-01, followed by F-ara-A, resulted in only a modest increase in apoptotic cells. The ability of UCN-01 to potentiate F-ara-A-mediated lethality was not mimicked by the selective PKC inhibitor bisindolylmaleimide, nor did treatment of cells with UCN-01 enhance formation of F-ara-ATP or increase incorporation of [3H]F-ara-A into DNA. Enhanced apoptosis in cells exposed sequentially or simultaneously to F-ara-A and UCN-01 was accompanied by a substantial reduction in colony formation (e.g., to 0.01% of control values). Cotreatment with UCN-01 also increased F-ara-A-mediated apoptosis and loss of delta psi(m) in U937 cells ectopically expressing Bcl-2, although not to the same extent as that observed in empty-vector controls. Finally, simultaneous exposure (24 h) of malignant B lymphocytes from the pleural effusion of a patient with indolent non-Hodgkin's lymphoma to F-ara-A and UCN-01 ex vivo resulted in a striking increase in apoptosis, as determined by terminal deoxynucleotidyltransferase-mediated nick end labeling assay. These findings indicate that UCN-01 increases F-ara-A-induced mitochondrial damage and apoptosis in human leukemia cells in a sequence-dependent manner, and that these events occur in at least some primary human lymphoma cells.
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PMID:Interactions between 2-fluoroadenine 9-beta-D-arabinofuranoside and the kinase inhibitor UCN-01 in human leukemia and lymphoma cells. 1123 87

Apocrine metaplasia is considered to be a benign lesion of human mammary epithelium. However, it is not known how apocrine differentiation develops, and whether there is a relationship with particular subtypes of mammary carcinoma. In order to investigate cell turnover in apocrine metaplasia, apoptosis was detected by terminal transferase nick-end-labelling, and Ki-67 was used as proliferation marker. Bcl-2, Bax, epidermal growth factor receptor (EGFR), and c-erbB2-encoded protein were detected by immunohistochemistry. The proliferative activity was low (<1%). Frequency and intraepithelial localization of apoptotic cells resembled those of normal mammary epithelium. Bax immunostaining was inconstant and weak, and Bcl-2 was not detectable in apocrine metaplasia. Immunoreactivity of the c-erbB2 gene product was membrane-bound and showed a moderate to strong intensity, whereas staining for EGFR was weak and inconsistent. When compared with normal breast epithelium, apocrine metaplasia shows a regular cell turnover at a low rate, although the expression patterns of regulatory proteins are clearly altered. Our data suggest that changes in the expression of Bcl-2 or c-erbB2 protein do not result in a significant imbalance of apoptosis and proliferation, and thus should not be interpreted as indicator for increased risk of neoplastic transformation.
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PMID:Cell turnover in apocrine metaplasia of the human mammary gland epithelium: apoptosis, proliferation, and immunohistochemical detection of Bcl-2, Bax, EGFR, and c-erbB2 gene products. 1125 28

The mitochondrial toxin 3-nitropropionic acid (3-NP) causes selective striatal lesions in rats and serves as an experimental model for the neurodegenerative disorder Huntington's disease (HD). Apoptotic cell death has been implicated for the neuronal degeneration that occurs in HD brains. The present study was designed to investigate whether the 3-NP-induced cell death in rats involves apoptosis and an altered expression of Bcl-2 family proteins. Systemic administration of 3-NP via subcutaneous Alzet pumps resulted in lesions of variable severity with neuronal loss and gliosis in the striatum. Using the terminal transferase-mediated biotinylated-UTP nick end-labelling (TUNEL) of DNA, TUNEL-positive cells exhibiting typical apoptotic morphology were detected only in the striatum of rats with a severe lesion. Furthermore, the neuronal expression of the pro-apoptotic protein Bax was strongly increased in the core of the severe lesion. Expression of the anti-apoptotic marker Bcl-2 was unchanged in this location, but was enhanced in the margins of the lesions. A moderately increased expression of both Bax and Bcl-2 was observed in dark neurones in the mild lesion and in the subtle lesion. The presence of nuclear DNA fragmentation, strong granular Bax expression and an increased Bax/Bcl-2 ratio in the centre of severe lesions suggests the occurrence of apoptotic cell death following 3-NP administration. In contrast, the dark compromised neurones observed in 3-NP-treated animals revealed an equally enhanced expression of both Bax and Bcl-2, but lacked TUNEL-labelling, and are therefore not apoptotic.
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PMID:The mitochondrial toxin 3-nitropropionic acid induces differential expression patterns of apoptosis-related markers in rat striatum. 1129 4

We investigated the frequency of spontaneous apoptosis and expression of the Bcl-2 family of proteins during normal spermatogenesis in man. Testicular tissue with both normal morphology and DNA content was obtained from necro-donors and fixed in Bouin's solution. A TdT-mediated dUTP end-labelling method (TUNEL) was used for the detection of apoptotic cells. Expression of apoptosis regulatory Bcl-2 family proteins and of p53 and p21(Waf1) was assessed by immunohistochemistry. Germ cell apoptosis was detected in all testes and was mainly seen in primary spermatocytes and spermatids and in a few spermatogonia. Bcl-2 and Bak were preferentially expressed in the compartments of spermatocytes and differentiating spermatids, while Bcl-x was preferentially expressed in spermatogonia. Bax showed a preferential expression in nuclei of round spermatids, whereas Bad was only seen in the acrosome region of various stages of spermatids. Mcl-1 staining was weak without a particular pattern, whereas expression of Bcl-w, p53 and p21(Waf1) proteins was not detected by immunohistochemistry. The results show that spontaneous apoptosis occurs in all male germ cell compartments in humans. Bcl-2 family proteins are distributed preferentially within distinct germ cell compartments suggesting a specific role for these proteins in the processes of differentiation and maturation during human spermatogenesis.
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PMID:Expression of Bcl-2 family proteins and spontaneous apoptosis in normal human testis. 1133 61

Frontotemporal dementia (FTD) is a neurodegenerative disease associated with aging for which the etiology is unclear. Relatively little is known about the pathology of this disease, which has only recently been a topic of investigation for dementia researchers. Though the known pathology of FTD includes neuron loss, the mechanism of neuronal death is not known. In this study, the authors investigated apoptotic pathways as a possible mechanism of neuronal cell death in FTD. They evaluated immunoreactivity for Bcl-2 family protein members Bcl-x and Bax in postmortem frontal cortex from FTD, AD, and control cases. Bcl-x(L), Bcl-x(S), and Bax all exhibited altered immunoreactivity in FTD cases as compared with control cases. Bcl-x immunoreactivity varied widely among both controls and FTD cases. However, Bcl-x(L) showed strong white matter immunoreactivity in all FTD cases, whereas white matter immunoreactivity was absent in controls. These trends in Bcl-x immunoreactivity suggest a strong white matter involvement in the pathology of FTD. Bax immunoreactivity also varied across all cases. Bax immunoreactivity was observed in terminal transferase dUTP nick ending labeling (TUNEL) positive neurons in both FTD and AD cases. However, one notable finding was immunoreactivity to Bax in astrocytes of FTD cases, as well as endothelial cells of the cerebrovasculature. Neither astrocytic nor endothelial cell immunoreactivity to Bax was exhibited in control or AD cases. Because Bax is a pro-apoptotic protein, this finding suggests the presence of a cerebrovascular component in the pathology of FTD. These findings, coupled with the proposed functions of the Bcl-2 family proteins, suggest that an apoptotic pathway may be responsible for neuron, and possibly astrocyte, death in FTD.
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PMID:Bcl-2 family protein behavior in frontotemporal dementia implies vascular involvement. 1140 49

Simian virus 40 small t antigen (st) is required for optimal transformation and replication properties of the virus. We find that in certain cell types, such as the human osteosarcoma cell line U2OS, st is capable of inducing apoptosis, as evidenced by a fragmented nuclear morphology and positive terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining of transfected cells. The cell death can be p53 independent, since it also occurs in p53-deficient H1299 cells. Genetic analysis indicates that two specific mutants affect apoptosis induction. One of these (C103S) has been frequently used as a PP2A binding mutant. The second mutant (TR4) lacks the final four amino acids of st, which have been reported to be unimportant for PP2A binding in vitro. However, TR4 unexpectedly fails to bind PP2A in vivo. Furthermore, a long-term colony assay reveals a potent colony inhibition upon st expression, and the behavior of st mutants in this assay reflects the relative frequency of nuclear fragmentation observed in transfections using the same mutants. Notably, either Bcl-2 coexpression or broad caspase inhibitor treatment could restore normal nuclear morphology. Finally, fluorescence-activated cell sorting analysis suggests a correlation between the ability of st to modulate cell cycle progression and apoptosis. Taken together, these observations underscore that st does not always promote proliferation but may, depending on conditions and cell type, effect a cell death response.
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PMID:Induction of p53-independent apoptosis by simian virus 40 small t antigen. 1153 78

Giant proerythroblasts are hallmarks of human parvovirus B19 infection. We attempted to characterize these cells in 5 patients with parvovirus B19-induced pure red cell aplasia using immunostaining of paraffin-embedded bone marrow sections with antibodies against erythroid-lineage-specific proteins, viral capsid antigen VP-1, and apoptosis- and cell-cycle-related proteins. Giant proerythroblasts are immunohistochemically consistent with early erythroid precursors of cells in the differentiation stage of CD34-, cytoplasmic spectrin+, glycophorin A-, and band-3-. VP-1 was expressed in the nucleus and cytoplasm of small- to medium-sized spectrin+ erythroid cells but not in giant proerythroblasts. The giant proerythroblasts displayed nuclear staining for p53 (41%+/-16%) and Ki-67 antigen (100%+/-0%) and cytoplasmic staining for Bax (65%+/-11%) and procaspase-3 (78%+/-10%), whereas they were not stained for p21Wafl/Cip1, active form of caspase-3, or terminal deoxynucleotidyltransferase-mediated deoxyuridine nick-end labeling (TUNEL). Antiapoptotic proteins, Bcl-2 and Mcl-1, were not expressed in the giant cells, and Bcl-x was infrequently expressed in these cells (11%+/-4%). These immunohistochemical findings suggest that giant proerythroblasts are proliferating erythroid precursors with accumulation of nonfunctional p53.
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PMID:Expression of p53 and Ki-67 antigen in bone marrow giant proerythroblasts associated with human parvovirus B19 infection. 1159 14

Dietary indole-3-carbinol (I3C) has clinical benefits for both cervical cancer and laryngeal papillomatosis, and causes apoptosis of breast cancer cells in vitro. We asked whether I3C and its major acid-catalyzed condensation product diindolylmethane (DIM), which is produced in the stomach after consumption of cruciferous vegetables, could induce apoptosis of cervical cancer cell lines. We also asked whether this effect could be observed in vivo. In vitro, both I3C and DIM caused accumulation of DNA strand breaks in three cervical cancer cell lines. Induction of apoptosis was confirmed by nuclear morphology, nucleosome leakage, altered cytoplasmic membrane permeability and caspase 3 activation. Neither I3C nor DIM caused apoptotic changes in normal human keratinocytes. In C33A cervical cancer cells, DIM was more potent than I3C [dose at which the number of viable cells was 50% of that in untreated cultures (LD(50)) = 50-60 micromol/L for DIM and 200 micromol/L for I3C in a mitochondrial function assay] and faster acting. Furthermore, I3C reduced Bcl-2 protein in a time- and dose-dependent manner. In HPV16-transgenic mice, which develop cervical cancer after chronic estradiol exposure, apoptotic cells were detected in cervical epithelium by TdT-mediated dUTP nick-end labeling staining and by immunohistochemical staining of active caspase 3 only in mice exposed to 17beta-estradiol (E2) and fed I3C. Rare apoptotic cells were also observed by hematoxylin and eosin staining in the spinous layer of the cervical epithelium in both control and transgenic mice. Estradiol reduced the percentage of these late-stage apoptotic cells in the cervical epithelium of transgenic, E2-treated mice, but this reduction was prevented by I3C. These data confirm the proapoptotic action of I3C on transformed cells in vitro, extend the observations to cervical cancer cells and to DIM and show for the first time that dietary I3C results in increased apoptosis in target tissues in vivo.
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PMID:Indole-3-carbinol and diindolylmethane induce apoptosis of human cervical cancer cells and in murine HPV16-transgenic preneoplastic cervical epithelium. 1173 83


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