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)

In previous reports, we have shown in SH-SY5 cells that olomoucine and roscovitine, two inhibitory drugs of cyclin-dependent kinases, caused apoptosis independent of the extrinsic pathway. In this experimental paradigm, apoptosis was refractory to the protective effects of either Bcl-2 or Bcl-XL overexpression. We are now reporting that the failure of Bcl-XL to prevent dell death was consistent with no effect on the kinetics of caspase activation and cytochrome c release. To further characterize this issue, we have discarded a direct effect of either olomoucine or roscovitine on mitochondrial permeability transition. Moreover, we have evidence that an intrinsic pathway took place in SH-SY5Y cells by showing the mitochondrial translocation of a GFP-Bax construct on transfection and treatment with cyclin-dependent kinase inhibitory drugs. Finally, we tested the effect of olomoucine and roscovitine on wild-type, bax-/-, bak-/-, and double bax-/-bak-/- mouse embryonic fibroblasts (MEF). In wild-type MEFs, both drugs induced cell death by apoptosis in a dose-dependent manner. In bax-/-, bak-/-, and, particularly, double bax-/-bak-/- MEFs, we observed the inhibition of apoptosis. In conclusion, olomoucine and roscovitine caused apoptosis through an intrinsic pathway, with Bax and Bak proteins being involved.
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PMID:BAX and BAK proteins are required for cyclin-dependent kinase inhibitory drugs to cause apoptosis. 1905 76

Resistance to growth suppression by TGF-beta1 is common in cancer; however, mutations in this pathway are rare in hematopoietic malignancies. In multiple myeloma, a fatal cancer of plasma cells, malignant cells accumulate in the TGF-beta-rich bone marrow due to loss of both cell cycle and apoptotic controls. Herein we show that TGF-beta activates Smad2 but fails to induce cell cycle arrest or apoptosis in primary bone marrow myeloma and human myeloma cell lines due to its inability to activate G(1) cyclin-dependent kinase (CDK) inhibitors (p15(INK4b), p21(CIP1/WAF1), p27(KIP1), p57(KIP2)) or to repress c-myc and Bcl-2 transcription. Correlating with aberrant activation of CDKs, CDK-dependent phosphorylation of Smad2 on Thr(8) (pT8), a modification linked to impaired Smad activity, is elevated in primary bone marrow myeloma cells, even in asymptomatic monoclonal gammopathy of undetermined significance. Moreover, CDK2 is the predominant CDK that phosphorylates Smad2 on T8 in myeloma cells, leading to inhibition of Smad2-Smad4 association that precludes transcriptional regulation by Smad2. Our findings provide the first direct evidence that pT8 Smad2 couples dysregulation of CDK2 to TGF-beta resistance in primary cancer cells, and they suggest that disruption of Smad2 function by CDK2 phosphorylation acts as a mechanism for TGF-beta resistance in multiple myeloma.
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PMID:CDK2 phosphorylation of Smad2 disrupts TGF-beta transcriptional regulation in resistant primary bone marrow myeloma cells. 1920 32

Fisetin, or 3,3',4',7-tetrahydroxyflavone, is present in fruits and vegetables and has been previously reported to inhibit the proliferation of a variety of cancer cells (Lu X, Jung J, Cho HJ, Lim do Y, Lee HS, Chun HS, Kwon DY, Park JH. J Nutr 135: 2884-2890, 2005). We have demonstrated in a previous work that 20-60 micromol/l fisetin inhibits cyclin-dependent kinase activities resulting in cell cycle arrest in HT-29 colon cancer cells. In the present study, we attempted to characterize the mechanisms by which fisetin induces apoptosis in HCT-116 cells. DNA condensations, cleavage of poly(ADP-ribose) polymerase (PARP), and cleavage of caspases 9, 7, and 3 were induced in HCT-116 cells treated with 5-20 micromol/l of fisetin. Fisetin induced a reduction in the protein levels of antiapoptotic Bcl-xL and Bcl-2 and an increase in the levels of proapoptotic Bak and Bim. Fisetin did not affect the Bax protein levels, but induced the mitochondrial translocation of this protein. Fisetin also enhanced the permeability of the mitochondrial membrane and induced the release of cytochrome c and Smac/Diablo. Additionally, fisetin caused an increase in the protein levels of cleaved caspase-8, Fas ligand, death receptor 5, and TNF-related apoptosis-inducing ligand, and the caspase-8 inhibitor Z-IETD-FMK suppressed fisetin-induced apoptosis and the activation of caspase-3. Furthermore, fisetin increases p53 protein levels, and the inhibition of p53 expression by small interference RNA resulted in a decrease in the fisetin-induced translocation of Bax to the mitochondria, release of mono- and oligonucleosome in the cytoplasm, and PARP cleavage. These results show that fisetin induces apoptosis in HCT-116 cells via the activation of the death receptor- and mitochondrial-dependent pathway and subsequent activation of the caspase cascade. The induction of p53 results in the translocation of Bax to the mitochondria, which contributes to fisetin-induced apoptosis in HCT-116 cells.
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PMID:Induction of p53 contributes to apoptosis of HCT-116 human colon cancer cells induced by the dietary compound fisetin. 1926 55

Prostate cancer (PC), which responds well to androgen ablation initially, invariably progresses to treatment resistance. The so-called androgen-independent PC is also a concern, since there is no effective therapy so far. Nkx3.1 is a putative prostate tumor suppressor that is expressed exclusively in the prostate under the regulation of androgen, and p27(KIP1) functions as a cell proliferation inhibitor and apoptosis trigger by disrupting the cyclin-dependent kinase (CDK)-cyclin complex. Lack of expressions of Nkx3.1 and/or p27(KIP1) have been detected in most advanced PC and is associated with poor clinical progression. Here, we show that endogenous expressions of both Nkx3.1 and p27(KIP1) are lost in the androgen-independent PC3 PC cells, while remaining intact in LNCaP PC cells, which contain functional androgen receptor (AR) and are hormone-responsive. Ectopic restoration of either Nkx3.1 or p27(KIP1) in PC3 cells results in reduced cell proliferation, and increased cell death. Both effects are synergistically enhanced when the two molecules are coexpressed. p27(KIP1) overexpression in PC3 results in increased cell population ceased at the G0/G1 phase, and this cell-cycle-arresting effect is significantly enhanced by the coexpression of Nkx3.1. Flow cytometry further revealed that Nkx3.1 and p27(KIP1) also cooperatively render more PC3 cells undergoing apoptosis. Consistently, the coexpression of Nkx3.1 and p27(KIP1) leads to the decreased expression of Bcl-2 oncogene and a concomitantly upregulated Bax expression. It also activates caspase 3 and leads to increased cleavage of PARP. Our findings thus reveal the crucial relevance of the combined antiproliferative and proapoptotic activities of Nkx3.1 and p27(KIP1) in androgen-independent PC cells, and further suggest that a combined, rather than single gene manipulation may be of clinical value for hormone-refractory PC.
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PMID:Nkx3.1 and p27(KIP1) cooperate in proliferation inhibition and apoptosis induction in human androgen-independent prostate cancer cells. 1926 49

Our goals were to examine the dual-directional regulation effects of resveratrol (1) in vitro by using MCF-7 cells (estradiol receptor-positive cells), study its mechanism of action, and give a systematical analysis of the regulatory networks of each related factor. An MTT test and growth curve showed that the proliferation of MCF-7 cells was inhibited by a high concentration of 1, and that its IC(50) was 8.70 x 10(-5) +/- 0.23 mol/l. However, 1 induced the proliferation of MCF-7 cells at 10(-7)-10(-5) mol/l, and resulted in a peak proliferation at 1.0 x 10(-7) mol/l. A high concentration of 1 arrested cell cycle progression at the G(1) phase, and a typical "sub-G(1) peak" of apoptotic cells was also observed by flow cytometry. The proliferation index of MCF-7 cells increased significantly with a low concentration of 1 (p < 0.05). 1 in high concentrations induced Bax, caspase-3, and cyclin-dependent kinase (CDK) inhibitor P21 expression, whereas the expressions of cyclin CDK2, Bcl-2, and proliferating cell nuclear antigen (PCNA) were decreased by 1 treatment. Conversely, treatment with low concentrations of 1 decreased the expression of P21 and Bax, while the expressions of cyclin CDK2, Bcl-2, and PCNA were increased. These results suggest that 1 had a dual-regulatory effect on MCF-7 cells. CDK-associated protein was a key factor at both the high and low concentrations used in this study.
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PMID:Effect of proliferation, cell cycle, and Bcl-2s of MCF-7 cells by resveratrol. 1943 Oct 20

Chronic lymphoid leukemias include well defined mature B-cell and T-cell neoplasms with diverse natural history and specific morphological, immunophenotypic and molecular characteristics. The most common adult leukemia in the Western world is chronic lymphocytic leukemia (CLL). Rarer indolent lymphoid leukemias include prolymphocytic leukemia, hairy cell leukemia, large granular lymphocyte leukemia and T-cell leukemia/lymphoma. Recently, several new agents have been explored and have shown promise in CLL treatment. Novel therapies are being evaluated both in pre-clinical studies and in early clinical trials. These treatments include new purine nucleoside analogs, antisense oligonucleotides, agents targeting the antiapoptotic Bcl-2 family of proteins, receptors involved in mediation of survival signals from the microenvironment, cyclin-dependent kinase inhibitors, protein kinase C inhibitors, tyrosine kinase inhibitors, immunomodulating drugs, new monoclonal antibodies and other agents. At present, available therapies are only partially efficient and there is an obvious need to develop better strategies and new, more specific and active drugs. This review will focus on agents currently being explored in preclinical studies and in early clinical trials.
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PMID:Novel drugs for chronic lymphoid leukemias: mechanism of action and therapeutic activity. 1951 88

Vanadium exerts a variety of biological effects, including antiproliferative responses through activation of the respective signaling pathways and the generation of reactive oxygen species. As epidermal cells are exposed to environmental insults, human keratinocytes (HaCaT) were used to investigate the mechanism of the antiproliferative effects of vanadyl(IV) sulfate (VOSO(4)). Treatment of HaCaT cells with VOSO(4) inhibited proliferation and induced apoptosis in a dose-dependent manner. Inhibition of proliferation was associated with downregulation of cyclins D1 and E, E2F1, and the cyclin-dependent kinase inhibitors p21(Cip1/Waf1) and p27(Kip1). Induction of apoptosis correlated with upregulation of the c-fos oncoprotein, changes in the expression of clusterin (CLU), an altered ratio of antiapoptotic to proapoptotic Bcl-2 protein family members, and poly(ADP-ribose) polymerase-1 cleavage. Forced overexpression of c-fos induced apoptosis in HaCaT cells that correlated with secretory CLU downregulation and upregulation of nuclear CLU (nCLU), a pro-death protein. Overexpression of Bcl-2 protected HaCaT cells from vanadium-induced apoptosis, whereas secretory CLU overexpression offered no cytoprotection. In contrast, nCLU sensitized HaCaT cells to apoptosis. Our data suggest that vanadium-mediated apoptosis was promoted by c-fos, leading to alterations in CLU isoform processing and induction of the pro-death nCLU protein.
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PMID:Vanadium-induced apoptosis of HaCaT cells is mediated by c-fos and involves nuclear accumulation of clusterin. 1953 Oct 52

Hepatocellular carcinoma (HCC) frequently includes abnormalities in cell cycle regulators, including up-regulated cyclin-dependent kinase (Cdks) activities due to loss or low expression of Cdk inhibitors. In this study, we show that xylocydine, a cyclin-dependent kinase (Cdk) specific inhibitor, is a good anti-cancer drug candidate for HCC treatment. Xylocydine (50muM) selectively down-regulates the activity of Cdk1 and Cdk2, accompanied by significant cell growth inhibition in HCC cells. Xylocydine also strongly inhibits the activity of Cdk7 and Cdk9, in vitro as well as in cell cultures, that is temporally associated with apoptotic cell death in xylocydine-induced HCC cells. This is associated with inhibition of phosphorylation of RNA polymerase II at serine residues 5 and 2, which are targets of Cdk7 and Cdk9, respectively. The effects on apoptosis are concomitant with changes in the levels of anti-apoptotic proteins, Bcl-2, XIAP, and survivin, which are markedly down-regulated, and pro-apoptotic molecules, p53 and Bax, which are elevated in HCC cells after treatment with xylocydine. The up-regulated level of p53 was associated with increased stability of the protein, as levels of Ser15 and Ser392 phsophorylated p53 are similarly elevated in the inhibitor treated cells. We demonstrated that xylocydine can effectively suppress the growth of HCC xenografts in Balb/C-nude mice by preferentially inducing apoptosis in the xenografts, whereas the drug did not cause any apparent toxic effect on other tissues. Taken together, these data suggest that the novel Cdk inhibitor xylocydine is a good candidate for an anti-cancer drug for HCC therapy.
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PMID:Xylocydine, a novel Cdk inhibitor, is an effective inducer of apoptosis in hepatocellular carcinoma cells in vitro and in vivo. 1961 71

We isolated two phytochemical lignans, schisandrin and schisandrin C, from Schizandra chinensis Baill and investigated their anti-cancer effects in human leukemia U937 cells. Schisandrin C inhibited cell growth in a dose-dependent manner, which was associated with the induction of G1 arrest of the cell cycle and apoptosis; schisandrin did not inhibit growth. Schisandrin C induced G1 arrest was correlated with down-regulation of cyclin D1, cyclin E, cyclin-dependent kinase (Cdk) 4 and E2Fs expression, inhibition of phosphorylation of retinoblastoma protein (pRB), and up-regulation of the Cdk inhibitor p21(WAF1/CIP1). In addition, schisandrin C-induced apoptosis was associated with down-regulation of expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL, proteolytic activation of caspase-3 and -9, and a concomitant degradation of poly(ADP-ribose) polymerase (PARP). Furthermore, schisandrin C-induced apoptosis was significantly inhibited by a caspase-3 specific inhibitor z-DEVD-fmk, indicating an important role for caspase-3 in the schisandrin C mechanism. In summary, growth inhibition by schisandrin C is related to cell cycle arrest at G1 and induction of caspase-3-dependent apoptosis in U937 cells; these findings suggest that schisandrin C may be a useful chemotherapeutic agent.
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PMID:Induction of G1 arrest and apoptosis by schisandrin C isolated from Schizandra chinensis Baill in human leukemia U937 cells. 1972 90

Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits anti-carcinogenic effect. The results of present study showed that NFD inhibited the proliferation of breast cancer MDA-MB-231 cells through the induction of S-phase arrest and apoptosis. NFD-induced S-phase arrest was associated with a marked decrease in the protein expression of cyclin A, cyclin B, and cyclin-dependent kinase (Cdk)2. NFD-induced apoptosis was characterized by increase of sub-G1 population, phosphatidylserine (PS) externalization, and activation of caspases. Moreover, up-regulation of Bad and down-regulation of Bcl-2, Bcl-X(L), and survivin led to the loss of mitochondrial membrane potential (DeltaPsim), the release of cytochrome c and sequential activation of caspase-9 and caspase-3. NFD activated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK) in MDA-MB-231 cells. Inhibitors of JNK (SP600125) and ERK (PD98059), but not p38 MAPK (SB203580) suppressed NFD-induced S-phase arrest and apoptosis in MDA-MB-231 cells. Both SP600125 and PD98059 attenuated Bad up-regulation, and reversed down-regulation of Bcl-2, Bcl-X(L), survivin, cyclin A, cyclin B, and Cdk2 in NFD-treated cells. Taken together, our data show that JNK and ERK-signaling pathways play important roles in NFD-mediated S-phase arrest and apoptosis of MDA-MB-231 cells.
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PMID:Naphtho[1,2-b]furan-4,5-dione induces apoptosis and S-phase arrest of MDA-MB-231 cells through JNK and ERK signaling activation. 1974 39


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