Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the effect of (-)-syringaresinol, a furofuran-type lignan isolated from Daphne genkwa, on cell cycle regulation in HL-60 human promyelocytic leukemia cells in vitro. (-)-Syringaresinol decreased the viability of HL-60 cells by inducing G(1) arrest followed by apoptosis in a dose- and time-dependent manner. The G(0)/G(1) phase of the cell cycle is regulated by cyclin-dependent kinases (Cdk), cyclins and cyclin-dependent kinase inhibitors (Cdki). We show by western blot analysis, that the (-)-syringaresinol-induced G(1) arrest was mediated through the increased expression of Cdki proteins (p21(cip1/waf1) and p27(kip1)) with a simultaneous decrease in cdk2, cdk4, cdk6, cyclin D(1), cyclin D(2), and cyclin E expression. The induction of apoptosis after treatment with (-)-syringaresinol for 24 h was demonstrated by morphological changes, DNA fragmentation, altered ratio of Bax/Bcl-2, cleavage of poly(ADP-ribose) polymerase and flow cytometry analysis. (-)-Syringaresinol also induced cytochrome c release and activation of caspase-3 and caspase-9. To our knowledge, this is the first time that (-)-syringaresinol has been reported to potently inhibit the proliferation of human promyelocytic HL-60 cells through G(1) arrest and induction of apoptosis. These findings suggest that (-)-syringaresinol may be a potential chemotherapeutic agent for the treatment of cancer.
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PMID:(-)-Syringaresinol inhibits proliferation of human promyelocytic HL-60 leukemia cells via G1 arrest and apoptosis. 1848 7

In this study, the effect of high glucose (HG) on endothelial progenitor cell (EPC) proliferation and its relationship with cyclins and reactive oxygen species (ROS) were investigated. Mouse EPCs were isolated from bone marrow using a magnetic activated cell-sorting system and cultured in the presence or absence of HG (30 mmol/l). We found that in the early stage of incubation (3 days), HG promoted cell proliferation, and increased the expressions of cdk2 and cyclin E, while in the late stage of culture (7 days) it inhibited cell proliferation and decreased the expressions of cdk2, cyclin E, and proliferating cell nuclear antigen (PCNA). Moreover, on the third day after incubation, HG significantly inhibited the apoptosis of EPCs, while in the late stage it markedly activated caspase-3 and promoted apoptosis. ROS generation in cells and maleic dialdehyde level in medium were significantly increased in HG group on the seventh day, whereas the expressions of superoxide dismutase and glutathione levels decreased. Tempol, a membrane-permeable radical scavenger, significantly inhibited ROS production in EPCs and partially reversed the HG-mediated inhibition of EPCs proliferation on the seventh day. We hypothesize that in the HG environment, the biphasic response of EPC proliferation may be related to the generation of ROS, which causes modulation of cyclins and cell cycle effect.
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PMID:Biphasic response of endothelial progenitor cell proliferation induced by high glucose and its relationship with reactive oxygen species. 1849 12

Human T-cell leukemia virus type-1 (HTLV-1) induces adult T-cell leukemia/lymphoma (ATL/L), a fatal lymphoproliferative disorder, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic progressive disease of the central nervous system after a long period of latent infection. Although the mechanism of transformation and leukemogenesis is not fully elucidated, there is evidence to suggest that the viral oncoprotein Tax plays a crucial role in these processes through the regulation of several pathways including NF-kappaB and the cell cycle pathways. The observation that NF-kappaB, which is strongly induced by Tax, is indispensable for the maintenance of the malignant phenotype of HTLV-1 by regulating the expression of various genes involved in cell cycle regulation and inhibition of apoptosis provides a possible molecular target for these infected cells. To develop potential new therapeutic strategies for HTLV-1 infected cells, in this present study, we initially screened a battery of NF-kappaB and CDK inhibitors (total of 35 compounds) to examine their effects on the growth and survival of infected T-cell lines. Two drugs namely BMS-345541 and Purvalanol A exhibited higher levels of growth inhibition and apoptosis in infected cell as compared to uninfected cells. BMS-345541 inhibited IKKbeta kinase activity from HTLV-1 infected cells with an IC50 (the 50% of inhibitory concentration) value of 50 nM compared to 500 nM from control cells as measured by in vitro kinase assays. The effects of Purvalanol A were associated with suppression of CDK2/cyclin E complex activity as previously shown by us. Combination of both BMS-345541 and Purvalanol A showed a reduced level of HTLV-1 p19 Gag production in cell culture. The apparent apoptosis in these infected cells were associated with increased caspase-3 activity and PARP cleavage. The potent and selective apoptotic effects of these drugs suggest that both BMS-345541 and Purvalanol A, which target both NF-kappaB and CDK complex and the G1/S border, might be promising new agents in the treatment of these infected patients.
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PMID:Two specific drugs, BMS-345541 and purvalanol A induce apoptosis of HTLV-1 infected cells through inhibition of the NF-kappaB and cell cycle pathways. 1854 67

Cobalamin-dependent methionine synthase, with a cofactor of vitamin B12, catalyzes the reaction of 5-methyltetrahydrofolate and homocysteine to form methionine and tetrahydrofolate, which takes a core position in folate cycle, one-carbon-unit transfer, and sulfur amino acid pathways. The 'methyl folate trap' hypothesis suggests that methionine synthase is a potential target for anticancer drug development. ZL031 and ZL033 are 5-methyltetrahydrofolate-like compounds that have been newly synthesized as potential inhibitors of the enzyme. To identify the effect of these two compounds on methionine synthase activity, a spectrophotometric assay was used and the results proved that ZL031 and ZL033 inactivated methionine synthase in HL-60 cells with an IC50 dose of 10.0 and 1.4 mumol/l, respectively. Moreover, obvious inhibitory effect on proliferation of HL-60 cells was observed, leading to our further investigation of the underlying anticancer mechanism. Under the circumstances of methionine synthase deficiency and subsequent folate depletion, cell cycle was arrested in G1/S phase and apoptosis was also observed. Analysis of cell cycle regulatory proteins demonstrated that cyclin E and cyclin-dependent kinase 2 were both increased. Furthermore, reduction of caspase-3, poly (ADP-ribose) polymerase, caspase-8, and caspase-9 protein levels were observed. In all the biological experiments we have performed, ZL033 has shown a better efficacy compared with ZL031. These results suggest that ZL031 and ZL033, as novel methionine synthase inhibitors, caused G1/S phase delay and apoptosis and eventually inhibit the proliferation of HL-60 cells in vitro. ZL033, with a carboxylic acid substituent, might have a better potential for drug development than ZL031 with an ester substituent.
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PMID:Two newly synthesized 5-methyltetrahydrofolate-like compounds inhibit methionine synthase activity accompanied by cell cycle arrest in G1/S phase and apoptosis in vitro. 1859 11

Tubulin and deoxyribonucleic acid (DNA) are two potential targets for the development of cancer chemotherapeutic agents. Mana-Hox is a synthetic derivative of beta-carboline, a structure relevant to marine sponge component, manzamine. In this study, Mana-Hox induced an inhibition of cell proliferation in several types of human cancer cell lines, including androgen-independent prostate cancer PC-3 and DU-145, hepatocellular carcinoma Hep3B and HepG2, and colorectal cancer HT-29 cells. The p53-null PC-3 cells were used for to anticancer mechanisms. Mana-Hox stimulated an increase of ataxia telangiectasia mutated (ATM) phosphorylation on Ser-1981, indicating the induction of DNA double-strand breaks. It also displayed an inhibitory effect on tubulin polymerization using tubulin turbidity assay and immunofluorescence identification. However, it only showed a minor inhibition on the activity of Aurora kinase and histone deacetylase. Mana-Hox induced mitotic arrest of the cell cycle identified by downregulation of cyclin E, cyclin A, and cyclin-dependent kinase 2 (Cdk2) and an increase of MPM-2 expression. Next, it caused Bcl-2 phosphorylation on Ser-70, downregulation of Mcl-1 expression, and activation of caspase-3, leading to apoptotic cell death. Notably, Mana-Hox was not a P-glycoprotein (P-gp) substrate and showed equipotent activity against P-gp-rich cancer cells. We conclude that Mana-Hox induces dual effects on DNA damage and tubulin depolymerization, leading to mitotic arrest and activation of mitochondria-mediated apoptotic pathways. Data provide evidence that the anticancer strategy of dual-action targets could be a potential anticancer approach.
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PMID:Mana-Hox displays anticancer activity against prostate cancer cells through tubulin depolymerization and DNA damage stress. 1866 30

Humic acid (HA) in well water used by the inhabitants for drinking is one of the possible etiological factors for Blackfoot disease (BFD). In this study, the ability of HA to inhibit cell cycle progression and induce apoptosis in cultured smooth muscle cells (SMCs; A7r5) was investigated. Treatment of the SMCs at various HA concentrations (25-200 microg/mL) resulted in sequences of events marked by apoptosis, as shown by loss of cell viability, morphology change, and internucleosomal DNA fragmentation. HA-induced apoptotic cell death that is associated with loss of mitochondrial membrane potential (Delta Psi m), cytochrome c translocation, caspase-3, -8, and -9 activation, poly ADP-ribose polymerase (PARP) degradation, dysregulation of Bcl-2 and Bax, and upregulation of p53 and phospholyrated p53 (p-p53) in SMCs. Flow cytometry analysis demonstrated that HA blocked cell cycle progress in the G1 phase in SMCs. This blockade of cell cycle was associated with reduced amounts of cyclin D1, CDK4, cyclin E, CDK2, and hyperphosphorylated retinoblastoma protein (pRb) in a time-dependent manner. Apparent DNA strand breaks (DNA damage) were also detected in a dose-dependent manner using Single-cell gel electrophoresis assay (comet assay). Furthermore, HA induced dose-dependent elevation of reactive oxygen species (ROS) level in SMCs, and antioxidant vitamin C and Trolox effectively suppressed HA-induced DNA damage and dysregulation of Bcl-2/Bax. Our findings suggest that HA-induced DNA damage, cell cycle arrest, and apoptosis in SMCs may be an underlying mechanisms for the atherosclerosis and thrombosis observed in the BFD endemic region.
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PMID:Humic acid induces G1 phase arrest and apoptosis in cultured vascular smooth muscle cells. 1868 88

In our previous study we have proved that colon cancer cells HT-29 pre-treated with specific 5-lipoxygenase inhibitor MK-886 became more susceptible to photodynamic therapy (PDT) with hypericin and we also found that this mutual combination induced cell cycle arrest and stimulated onset of apoptosis (Kleban et al., 2007. J. Photochem. Photobiol. B 84, 2). To further explain events associated with MK-886 mediated sensitization of tumor cells toward PDT with hypericin, more detailed study of signaling pathways leading to increase in apoptosis as well as cell cycle perturbations was performed and is presented herein. Intensive accumulation of HT-29 cells in G0/G1 phase of cell cycle led to expression analyses of several G0/G1 checkpoint molecules (cyclin A, cyclin E, cdk-2, pRb). Similarly, accumulation of apoptotic cells invoked analyses of key molecules involved in apoptotic signaling (caspase-3, -8, -9; PARP; Lamin B; Mcl-1; Bax) by Western blotting and caspase activity assay. Long term survival of cells was examined by clonogenicity test. As the effect of PDT is mediated by ROS production, levels of hydrogen peroxides and superoxide anion were monitored by flow cytometric analyses. In addition, an impact of MK-886 on LTB4 production and expression of 5-LOX was monitored. Massive G0/G1 arrest in the cell cycle accompanied by increase in cyclin E level and decrease/absention of cyclin A, cdk-2 and pRb expression indicated incapability for G1/S transition. Minimal changes in cleavage of procaspases observed in cells treated with non-toxic concentrations of either agent alone or their mutual combination were not quite in line with their activity (caspase-3, -8, -9) which was significantly increased mainly in combinations. Treatment with non-toxic concentration of MK-886 had minimal influence over ROS production compared to control cells. In contrast, hypericin alone markedly increased the level of ROS, but no additional effect of MK-886 pre-treatment was detected. Further analyses of particular ROS groups unveiled an impact of increasing MK-886 concentration on superoxide accumulation accompanied with depletion of hydrogen peroxide level within the cells. The clonogenicity test revealed disruption of colony formation after mutual combination of both agents as compared to MK-886 or PDT alone. In conclusion, we presume that stimulation of apoptosis in our experimental model was accomplished preferentially through the mitochondrial pathway, although caspase-8 activation was also noticed. Interestingly, pre-treatment with MK-886 modulated distribution of ROS production in mutual combination with PDT.
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PMID:Mechanisms involved in the cell cycle and apoptosis of HT-29 cells pre-treated with MK-886 prior to photodynamic therapy with hypericin. 1877 33

Cytotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, have potential therapeutic activity in tumor therapy. However, the therapeutic effect in solid tumor treatment with CTX III are still largely unknown. In the present study, we investigated whether CTX III affects cell growth and cell cycle progression of hepatocellular carcinoma cell (HepG2). We found that the proliferation of HepG2 cell was inhibited by CTX III, to some extent, in a time- and dose-dependent manner (IC50 2.58microg/ml at 24h). Flow cytometric analysis and annexin V labeling also demonstrated that CTX III increased the percentage of apoptotic cells being associated with cell cycle arrest at S-phase. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot revealed that cyclin D1, cyclin A and cyclin E, which involved in cell apopotosis and cell cycle progression, were down regulated both at transcription and translation levels. CTX III-induced caspase-8, -9 and caspase-3 activation, generation of truncated Bid, releasing of cytochrome c and the change of Bcl-2/Bax ratio on protein and mRNA levels. These findings demonstrated that cyclin D1, cyclin B and cyclin A down-regulation, change of Bcl-2/Bax ratio and caspase-8 and -9 activation contribute to CTX III-induced HepG2 cell apoptosis.
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PMID:Apoptosis of human hepatocellular carcinoma cell (HepG2) induced by cardiotoxin III through S-phase arrest. 1898 2

N(6)-isopentenyladenosine (i6A) is a modified nucleoside with a pentaatomic isopentenyl derived from mevalonate that induces inhibition of tumor cell proliferation and apoptosis in several tumor cell lines. In this study, we reported that N(6)-isopentenyladenosine inhibited the proliferation and promotes apoptosis in DLD1 human colon cancer cells. It suppressed the proliferation of cells through inhibition of DNA synthesis, causing a cell cycle arrest that correlated with a decrease in the levels of cyclin E, cyclin A and cyclin D1 and with a concomitant increase in the levels of cyclin-dependent kinase inhibitor p21waf and p27kip1. Moreover, it induced apoptosis through an increase in the number of annexin V-positive cells, a downregulation of antiapoptotic products and caspase-3 activation. The apoptotic effects of N(6)-isopentenyladenosine were accompanied by sustained phosphorylation and activation of c-jun N-terminal kinase (JNK) that induced phosphorylation of c-jun. Overall, our data show that JNK, could play an important role in i6A-mediated apoptosis in DLD1 human colon cancer cells.
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PMID:N6-isopentenyladenosine inhibits cell proliferation and induces apoptosis in a human colon cancer cell line DLD1. 1905 78

Duchesnea indica (Andr.) Focke has been commonly used to treat cancer in Asian countries for centuries, and recently has been shown to possess anticancer properties in vitro and in vivo. But the underlying mechanism of the anticancer action is unclear, especially in in vivo studies. In this study, we investigated the anticancer effect and associated mechanisms of Duchesnea phenolic fraction (DPF) on cervical cancer in vitro and in vivo. Our results showed that DPF significantly inhibited cervical cancer cell proliferation in dose- and time-dependent manners. DPF induced apoptosis as determined by AO/EB staining, DNA fragmentation and flow cytometry. Some apoptosis correlated proteins were altered following DPF treatment. Bax was up-regulated while Bcl-2 was down-regulated, and the expression ratio of Bax/Bcl-2 was increased. These resulted in the translocation of Bax to mitochondria, the release of cytochrome c from the mitochondria to the cytosol and caspase-3 activation. Concurrently, DPF provoked S phase arrest along with significant down-regulation of S phase-associated proteins, such as cyclin A, cyclin E, cyclin D1 and cdk2. Transplanted U14 cervical cancer mouse model was used to evaluate the antitumor effect of DPF in vivo. Compared with control, DPF treatment markedly prolonged survival of tumor-bearing mice and dose-dependently reduced the tumor weight. DPF could induce apoptosis in tumor tissues as evidenced by increased TUNEL-positive cells, activation of caspase-3, up-regulation of Bax and down-regulation of Bcl-2. In addition, DPF significantly decreased the expression of cell proliferation markers PCNA and ki67 in tumors. All together, these data sustain our contention that DPF has anticancer properties and merits further investigation as a potential therapeutic agent.
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PMID:Duchesnea phenolic fraction inhibits in vitro and in vivo growth of cervical cancer through induction of apoptosis and cell cycle arrest. 1906 47


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