UNIPROT:P10415 - FACTA Search

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Query: UNIPROT:P10415 (Bcl-2)
33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endocrine treatments for human breast cancer have been based largely upon the removal of estrogenic stimuli. The regression of tumors after estrogen deprivation has generally been characterized as being due to reduced proliferation but more recently has been recognized to also involve increased apoptosis. The aim of our experiments was to define the associated changes in certain proliferation- and cell death-related biological parameters after hormone withdrawal from estrogen-dependent MCF-7 xenografts in athymic nude mice using immunohistochemical techniques. The baseline estrogen receptor (ER) level of this MCF-7 xenograft was relatively low (average H score 23) but it was strongly Bcl-2-, PgR- and pS2-positive, indicating the functional integrity of estrogen signaling. Changes in proliferation (Ki-67), apoptosis, ER, progesterone receptor (PgR), cyclin D1, p27kip1, Bcl-2 and Bax expression were assessed during the 2 weeks after estrogen deprivation. ER levels rose markedly after estrogen ablation, whereas PgR levels fell to about 10% of baseline and pS2 levels halved. The proportion of Ki-67-positive cells was unchanged after 24 hr but by day 14 had reduced by about 80%. The normal levels of cyclin D1 also reduced after estrogen withdrawal in contrast to the rapid increase in levels of cyclin-dependent kinase inhibitor p27kip1. This latter increase appeared to occur in advance of the changes in Ki-67. The proportion of apoptotic cells increased from a mean 1.5% at baseline to 2.9% after 3 days and 4.7% after 14 days. There were reductions in both Bcl-2 and Bax staining but these appeared to be greater for Bcl-2, effectively decreasing the Bcl-2/Bax ratio. Our results provide a framework for the use of these parameters as intermediate markers in comparisons of hormonal agents for human breast cancer treatment.
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PMID:Time-related effects of estrogen withdrawal on proliferation- and cell death-related events in MCF-7 xenografts. 1018 36

p27kip1 and p21cip1 are cyclin-dependent kinase (cdk) inhibitors which along with p53 play critical roles in the control of cell cycle progression. Accumulation of p27kip1 in post-mitotic neurons is a major event of neurogenesis. We hypothesized that a dysregulation of the expression of p53 and these cdk inhibitors underlies cellular proliferation in medulloblastomas, and tested this hypothesis by investigating p27kip1, p21cip1, Bcl2 and p53 immunoreactivity in 14 medulloblastoma tumors. We noted an inverse relationship between p27kip1 expression and cellular proliferation (MIB1). Focal islands of neuroblastic or glial differentiation expressed high levels of p27kip1, while the undifferentiated, highly-proliferative population of tumor cells showed no detectable p27kip1 expression, thus suggesting a role for p27kip1 in cell cycle control in medulloblastoma. In addition, there was no detectable p21cip1 expression in any of the medulloblastomas studied. The low level of apoptosis displayed by these tumors was not associated with the expression of Bcl-2. A significant relationship was found between detection of p53 protein and poor survival. Since, p21cip1 and p27kip1 are often co-expressed with other INK4 family of cdk inhibitors during the induction of cellular differentiation and are synergistic in their effect, a deregulation of their coordinate expression may underlie the lack of complete differentiation in medulloblastoma.
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PMID:Expression of p27kip1 and p53 in medulloblastoma: relationship with cell proliferation and survival. 1078 68

On a series of thirty trephine bone marrow biopsies from patients with multiple myeloma, the authors evaluated expression of markers of cell proliferation or of its blockade (Ki-67, PCNA, topoisomerase IIa, cyclin D-1, AgNOR, and p27kip1) and markers indicating multidrug resistance (P-170 and Bcl-2). Expression of Ki-67 and of topoisomerase IIa was unfrequent. Marked positivity of PCNA was expressed in about one third of cases, negative staining was exceptional. No expression of cyclin D-1 was noted. Positivity of p27kip1 was frequent. P-170 was demonstrated in a small number of cases, Bcl-2 was strongly positive in most cases. The results characterise multiple myeloma as a tumour with low proliferation rate and, simultaneously, with high resistance to apoptosis.
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PMID:[Biological characteristics of multiple myeloma]. 1097 46

Optimal T-cell activation requires both an antigen-specific and a costimulatory signal. The outcome of T-cell activation can be influenced by the nature of the costimulatory signal the T cell receives. We recently demonstrated the ability of stimulation through intercellular adhesion molecule-1 (ICAM-1), resident on the T-cell surface, to provide a second signal for T-cell activation, and have extended that work here to begin an examination of the functional outcome of this set of signals. Costimulation through ICAM-1 resulted in a greater percentage of cells having undergone more than three divisions when compared to costimulation through leucocyte function-associated antigen-1 (LFA-1). Costimulation through ICAM-1 also had an effect similar to costimulation through CD28 in its ability to down-regulate the cyclin dependent kinase inhibitor p27kip1. Costimulation through ICAM-1 provided greater protection from apoptosis than costimulation through LFA-1, especially in cells having divided more than three times. This was supported by the ability of costimulation through ICAM-1 to up-regulate the anti-apoptotic protein Bcl-2. Finally, costimulation through ICAM-1 or CD28 produced a greater number of T cells with a memory phenotype than costimulation through LFA-1.
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PMID:The outcome of T-cell costimulation through intercellular adhesion molecule-1 differs from costimulation through leucocyte function-associated antigen-1. 1256 23

Mutations in the human homologue of Drosophila Patched1 (PTCH1) have been found in several common tumours including basal cell carcinoma, medulloblastoma, and rhabdomyosarcoma (RMS). Medulloblastoma and RMS are also present in the murine model for Ptch1 deficiency. Tumours in heterozygous Ptch1(neo67/+) mice consistently exhibit elevated transcript levels of the proto-oncogene Gli1, of Ptch1 itself, and of the insulin-like growth factor 2 (Igf2). The present study has investigated additional molecular changes in RMSs of Ptch1 mutant mice by means of microarray analysis and protein expression analysis. The data show activation of the cell survival-promoting Akt/protein kinase B (Pkb). Furthermore, RMSs express increased levels of the anti-apoptotic protein Bcl-2 and of genes and proteins known to inhibit cell proliferation, including Gadd45a and p27kip1. Taken together, the data suggest that the formation of RMSs in Ptch1 mutants is associated with the ability of tumour cells to resist apoptosis.
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PMID:Molecular characterization of Patched-associated rhabdomyosarcoma. 1284 31

Resveratrol (3,4',5-trihydroxystilbene) is a phytoalexin found in grapes and other food products that can prevent cancer. We studied the in vitro biological activity of this compound by examining its effect on proliferation and inducing apoptosis in three lung cancer cell lines (A549, EBC-1, Lu65). Resveratrol inhibited the growth of A549, EBC-1 and Lu65 lung cancer cells by 50% (ED50) at concentrations between 5-10 microM. We also examined the combined effects in these cells of resveratrol and paclitaxel, an essential chemotherapeutic agent against lung cancer. Although simultaneous exposure to resveratrol plus paclitaxel did not result in significant synergy, resveratrol (10 microM, 3 days) significantly enhanced the subsequent antiproliferative effect of paclitaxel. In addition, resveratrol as well as paclitaxel induced apoptosis in EBC-1 and Lu65 cells, as measured by TUNEL and caspase assays, as well as flow cytometry. Resveratrol (10 microM, 3 days) similarly enhanced the subsequent apoptotic effects of paclitaxel. We examined the effects of resveratrol and paclitaxel on levels of p21waf1, p27kip1, E-cadherin, EGFR and Bcl-2 in EBC-1 cells. Resveratrol (10 microM, 3 days) prior to paclitaxel induced p21waf1 expression approximately 4-fold. These results suggest that resveratrol may be a promising alternative therapy for lung cancer and that lung cancer cells exposed to resveratrol have a lowered threshold for killing by paclitaxel.
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PMID:Combined effects of resveratrol and paclitaxel on lung cancer cells. 1466 16

Cell proliferation and apoptosis are controlled by tightly orchestrated signaling pathways that culminate in transcriptional activation/repression of multiple proteins. Dysregulation of cell cycle and/or apoptosis control may lead to genomic instability, neoplastic transformation and tumor progression. Under certain conditions, some hexavalent chromium [Cr(VI)] compounds are toxic and carcinogenic in the human respiratory tract, and we have shown that they induce apoptosis and/or cell cycle arrest in a p53-dependent fashion. There is increasing evidence linking extracellular signal-regulated kinase (ERK) activation with the DNA damage response, by both p53-dependent and -independent mechanisms. Here, the aim was to study the effect of Cr(VI) transcriptional regulation of key cell cycle inhibitors and pro- and anti-apoptotic proteins, as well as the role of ERK activation in the Cr(VI) genotoxic response. Diploid human lung fibroblasts were incubated with 3-9 uM Na2CrO4, and RNA was isolated at 4, 8, and 24 h, as well as 24 h after Cr(VI) exposure was terminated (recovery). mRNA expression was quantitated by RNase protection assay with a 32P-labeled multi-transcript probe containing gene sequences for the cdk inhibitors, p21waf1/cip1, p27kip1, p16INK4a, p15INK4b; the pro-apoptotic proteins bcl-XS and bax; the anti-apoptotic proteins bcl-W, bcl-XL, and bcl2, GADD45, and cyclin A. In general, bcl-W and bcl-XL expression were both downregulated after Cr exposure, to around 50% at 24 h, which was more pronounced after the recovery period. At Cr(VI) concentrations < or = 6 uM, bcl2 expression was upregulated. Of particular interest is that bax expression was reduced, in a dose and time-dependent fashion, however that of bcl-XS was elevated by nearly 3-fold after 8 h, and declined to control levels at the end of the recovery period. Expression of GADD45 and p21 were both upregulated by 2-fold at 8 h, but declined to control levels during recovery. Neither the expression of p27 nor that of p16 were apparently affected by Cr(VI) exposure, however the expression of p15 was markedly increased after exposure to all concentrations of Cr(VI). Finally, the expression of cyclin A was decreased after 24 h Cr(VI) exposure. Cr(VI) induced a transient burst of ERK activity (2-6-fold over control) around 0.5-3 h after exposure. However, inhibition of ERK activation with PD98059 had no effect on the Cr-induced alterations in gene expression. Moreover, Cr(VI)-induced clonogenic lethality, as assessed after 24 h exposure to 1 and 2 uM Cr(VI), was also not affected by ERK inhibition. These data suggest that both p53-dependent and -independent apoptotic and growth-inhibitory pathways are markedly affected by Cr(VI) exposure. However, the ability of Cr(VI) to affect key apoptotic and growth arresting genes, and thus clonogenic lethality, appears to be independent of ERK. Continued investigation into the cellular and molecular mechanisms of Cr(VI)-induced cell cycle and apoptosis control should further the understanding of Cr(VI)-associated carcinogenesis.
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PMID:Induction of pro-apoptotic and cell cycle-inhibiting genes in chromium (VI)-treated human lung fibroblasts: lack of effect of ERK. 1497 55

Mesangial cell (MC) proliferation is essential for the pathogenesis and progression of glomerular disease. Using an acute model of mesangial proliferative glomerulonephritis (Thy1 GN), we show that neutralization of interleukin (IL)-10 greatly ameliorated the disease as expressed by both decreased MC expansion and proteinuria. Treatment with the tellurium compound AS101 (ammonium trichloro(dioxoethylene-o,o')tellurate) resulted in favorable effects provided that the compound was administered 24 h before insult, whereas partial effects were obtained when administered after insult. We identified STAT3 as playing a pivotal role in IL-10-induced MC proliferation in vitro and in vivo. IL-10 activates MC STAT3 in vitro as expressed by its phosphorylation and nuclear translocation. The role of STAT3 in MC proliferation induced by IL-10 was deduced from results showing that IL-10-induced proliferation was abrogated if MC transfected with STAT3 antisense oligonucleotides were used or if cells were incubated with inhibitors of STAT3. AS101 deactivates STAT3 in control but not in MC transfected with IL-10 antisense oligonucleotides. Inactivation of STAT3 prevents reduction of MC proliferation by AS101. We further demonstrate the role of STAT3 in the regulation of cell cycle and survival regulatory proteins by AS101 in MC via inhibition of IL-10. IL-10 increased MC expression of Bcl-2 and Bcl-X1 and simultaneously decreased the levels of p27kip1. These survival factors were decreased by AS101 in a STAT3- and IL-10-dependent manner, whereas p27kip1 was similarly increased. In Thy1 GN, phosphorylated STAT3 in glomerular MC peaked at day 6 and correlated with MC expansion. Neutralization of IL-10 or its inhibition by AS101 abolished phosphorylation of STAT3. This effect positively correlated with amelioration of the disease. These in vitro and in vivo studies indicate that the autocrine MC growth factor IL-10 induces MC proliferation via STAT3. We suggest that IL-10 or its downstream target STAT3 might be therapeutic targets for kidney diseases induced by mesangial proliferation.
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PMID:Inhibition of interleukin-10 by the immunomodulator AS101 reduces mesangial cell proliferation in experimental mesangioproliferative glomerulonephritis: association with dephosphorylation of STAT3. 1500 75

Interleukin (IL)-7 is essential for normal T cell development. Previously, we have shown that IL-7 increases viability and proliferation of T cell acute lymphoblastic leukemia (T-ALL) cells by up-regulating Bcl-2 and down-regulating the cyclin-dependent kinase inhibitor p27kip1. Here, we examined the signaling pathways via which IL-7 mediates these effects. We investigated mitogen-activated protein kinase (MEK)-extracellular signal-regulated kinase (Erk) and phosphatidylinositol-3-kinase (PI3K)-Akt (protein kinase B) pathways, which have active roles in T cell expansion and have been implicated in tumorigenesis. IL-7 induced activation of the MEK-Erk pathway in T-ALL cells; however, inhibition of the MEK-Erk pathway by the use of the cell-permeable inhibitor PD98059, did not affect IL-7-mediated viability or cell cycle progression of leukemic cells. IL-7 induced PI3K-dependent phosphorylation of Akt and its downstream targets GSK-3, FOXO1, and FOXO3a. PI3K activation was mandatory for IL-7-mediated Bcl-2 up-regulation, p27kip1 down-regulation, Rb hyperphosphorylation, and consequent viability and cell cycle progression of T-ALL cells. PI3K signaling was also required for cell size increase, up-regulation of CD71, expression of the glucose transporter Glut1, uptake of glucose, and maintenance of mitochondrial integrity. Our results implicate PI3K as a major effector of IL-7-induced viability, metabolic activation, growth and proliferation of T-ALL cells, and suggest that PI3K and its downstream effectors may represent molecular targets for therapeutic intervention in T-ALL.
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PMID:Activation of PI3K is indispensable for interleukin 7-mediated viability, proliferation, glucose use, and growth of T cell acute lymphoblastic leukemia cells. 1535 58

The proteasome plays a critical role in the degradation of proteins involved in the regulation of cell cycle, apoptosis, and angiogenesis. Bortezomib is the first in a new class of antineoplastic agents known as proteasome inhibitors to become available for clinical use. Bortezomib targets pathways relevant to tumor progression and therapy resistance and can directly modulate expression of cyclins, p27kip1, p53, nuclear factor-kB, Bcl-2, and Bax. In in vitro and in vivo, growth inhibition and apoptosis have been observed in tumor cells following exposure to bortezomib. Currently, bortezomib is approved for the treatment of patients with relapsed and/or refractory multiple myeloma who have received > or =2 therapies and progressed on their most recent therapy. Efforts are now being directed toward exploring the use of bortezomib in the treatment of advanced non-small-cell lung cancer (NSCLC). Clinical trials using bortezomib as monotherapy or in combinations, such as with taxanes, gemcitabine and platinums, and novel agents are under way, and preliminary results have demonstrated activity with bortezomib as a single agent and in combination with chemotherapy in advanced NSCLC. In addition, pharmacogenomics and biomarker analysis are being used in an attempt to identify tumor types likely to respond to treatment with bortezomib.
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PMID:Use of proteasome inhibition in the treatment of lung cancer. 1563 66

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