Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.22 (cdc2)
 8,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostate cancer (PCa) is the leading cause of cancer-related deaths in men; urgent measures are warranted to lower this deadly malignancy. Silymarin is a known cancer chemopreventive agent, but the relative anticancer efficacy of its constituents is still unknown. Here, we compared the efficacy of 7 pure flavonolignan compounds isolated from silymarin, namely silybin A, silybin B, isosilybin A, isosilybin B, silydianin, isosilydianin, silychristin and isosilychristin, in advanced human PCa PC3 cells. Silybin A, silybin B, isosilybin A, isosilybin B, silibinin and silymarin strongly inhibited the colony formation by PC3 cells (p < 0.001), while silydianin, silychristin and isosilychristin had marginal effect (p < 0.05). Using cell growth and death assays, we identified isosilybin B as the most effective isomer. FACS analysis for cell cycle also showed that silybin A, silybin B, isosilybin A, isosilybin B, silibinin and silymarin treatment resulted in strong cell cycle arrest in PC3 cells after 72 hr of treatment, while the effect of silydianin, silychristin and isosilychristin was marginal (if any). Western blot analysis also showed the differential effect of these compounds on the levels of cell cycle regulators-cyclins (D, E, A and B), CDKs (Cdk2, 4 and Cdc2), CDKIs (p21 and p27) and other cell cycle regulators (Skp2, Cdc25A, B, C and Chk2). This study provided further evidence for differential anticancer potential among each silymarin constituent, which would have potential implications in devising better formulations of silymarin against prostate and other cancers.
 ...
PMID:Identifying the differential effects of silymarin constituents on cell growth and cell cycle regulatory molecules in human prostate cancer cells. 1843 16

Checkpoint pathways inhibit mitotic progression by inducing the phosphorylation of serine 216 in cdc25C resulting in the generation of a 14-3-3 binding site on cdc25C. Two 14-3-3 isoforms, 14-3-3epsilon and 14-3-3gamma form a complex with cdc25C and inhibit cdc25C function. To examine the contribution of 14-3-3gamma to checkpoint regulation, the expression of 14-3-3gamma was inhibited in HCT116 cells using vector based RNA interference. A transient reduction in the expression of 14-3-3gamma in HCT116 cells resulted in an override of both the incomplete S phase and the G(2) DNA damage checkpoint. A 14-3-3gamma knockdown clone also showed an override of both checkpoint pathways. These phenotypes were reversed upon expression of a shRNA resistant 14-3-3gamma cDNA. Override of the G(2) DNA damage checkpoint pathway was accompanied by a decrease in the levels of inhibitory phosphorylation on cdc25C and cdk1. However, there was no difference in the gamma-H2AX foci formation and levels of phospho-chk1 and phospho-chk2, suggesting that activation of the DNA damage checkpoint response and subsequent activation of the checkpoint kinases Chk1 and Chk2 was not perturbed. These results suggest that the override of checkpoint observed in 14-3-3gamma knockdown cells is due to failure to inhibit cdc25C function.
 ...
PMID:14-3-3 Gamma is required to enforce both the incomplete S phase and G2 DNA damage checkpoints. 1884 1

Quercetin is a flavonoid present in many vegetables, fruits, and beverages. Due to its anti-oxidant, anti-tumor, and anti-inflammatory activity, quercetin has been studied extensively as a chemoprevention agent in several cancer models. Since most of these studies used higher doses of quercetin than clinically achievable, we focused on the effectiveness of physiologically relevant doses of quercetin. A low dose of quercetin exerted cancer cell-specific inhibition of proliferation and this inhibition resulted from cell cycle arrest at the G(1) phase. Quercetin induced p21 CDK inhibitor with a concomitant decrease of phosphorylation of pRb, which inhibits the G(1)/S cell cycle progression by trapping E2F1. A low dose of quercetin induced mild DNA damage and Chk2 activation, which is the main regulator of p21 expression by quercetin. In addition, quercetin down-regulated the cyclin B1 and CDK1, essential components of G(2)/M cell cycle progression. Inhibition of the recruitment of key transcription factor NF-Y to cyclin B1 gene promoter by quercetin led to transcriptional inhibition. This study proved that the chemo-preventive efficacy of a physiologically relevant dose of quercetin can be achievable through the inhibition of cell cycle progression.
 ...
PMID:Effects of low dose quercetin: cancer cell-specific inhibition of cell cycle progression. 1900 57

Emodin was isolated from Rheum palmatum L. and exhibits an anticancer effect on human cancer cell lines, however, the molecular mechanisms of emodin-mediated apoptosis in human tongue cancer cells have not been fully investigated. In this study, treatment of human tongue cancer SCC-4 cells with various concentrations of emodin led to G2/M arrest through promoted p21 and Chk2 expression but inhibited cyclin B1 and cdc2; it also induced apoptosis through the pronounced release of cytochrome c from mitochondria and activations of caspase-9 and caspase-3. These events were accompanied by the generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential (delta psi(m)) and a decrease in the ratio of mitochondrial Bcl-2 and Bax content; emodin also promoted the levels of GADD153 and GRP78. The free radical scavenger N-acetylcysteine and caspase inhibitors markedly blocked emodin-induced apoptosis. Taken together, these findings suggest that emodin mediated oxidative injury (DNA damage) based on ROS production and ER stress based on the levels of GADD153 and GRP78 that acts as an early and upstream change in the cell death cascade to caspase- and mitochondria-dependent signaling pathways, triggers mitochondrial dysfunction from Bcl-2 and Bax modulation, mitochondrial cytochrome c release and caspase activation, consequently leading to apoptosis in SCC-4 cells.
 ...
PMID:Emodin induces apoptosis of human tongue squamous cancer SCC-4 cells through reactive oxygen species and mitochondria-dependent pathways. 1933 Nov 69

This study is the first to investigate the anticancer effect of isoliquiritigenin (ISL) in human cervical carcinoma HeLa cells. The results reveal that ISL inhibits HeLa cells by blocking cell cycle progression in the G2/M phase and inducing apoptosis. Blockade of cell cycle is associated with increased activation of ataxia telangiectasia-mutated (ATM). Activation of ATM by ISL phosphorylated p53 at Serine15, resulting in increased stability of p53 by decreasing p53 and murine double minute-2 (MDM2) interaction. In addition, ISL-mediated G2/M phase arrest was also associated with decreases in the amounts of cyclin B, cyclin A, cdc2, and cdc25C, and increases in the phosphorylation of Chk2, cdc25C, and cdc2. The specific ATM inhibitor caffeine significantly decreased ISL-mediated G2/M arrest by inhibiting the phosphorylation of p53 (Serine15) and Chk2. ISL induced apoptotic cell death is associated with changes in the expression of Bax and Bak, decreasing levels of Bcl-2 and Bcl-X(L), and subsequently triggering mitochondrial apoptotic pathway. In addition, pretreatment of cells with caspase-9 inhibitor blocked ISL-induced apoptosis, indicating that caspase-9 activation is involved in ISL-mediated HeLa cell apoptosis. These findings suggest that ISL may be a promising chemopreventive agent against human uterine cervical cancer.
 ...
PMID:Shallot and licorice constituent isoliquiritigenin arrests cell cycle progression and induces apoptosis through the induction of ATM/p53 and initiation of the mitochondrial system in human cervical carcinoma HeLa cells. 1953 69

The human single-stranded DNA-binding protein, replication protein A (RPA), is regulated by the N-terminal phosphorylation of its 32-kDa subunit, RPA2. RPA2 is hyperphosphorylated in response to various DNA-damaging agents and also phosphorylated in a cell-cycle-dependent manner during S- and M-phase, primarily at two CDK consensus sites, S23 and S29. Here we generated two monoclonal phospho-specific antibodies directed against these CDK sites. These phospho-specific RPA2-(P)-S23 and RPA2-(P)-S29 antibodies recognized mitotically phosphorylated RPA2 with high specificity. In addition, the RPA2-(P)-S23 antibody recognized the S-phase-specific phosphorylation of RPA2, suggesting that during S-phase only S23 is phosphorylated, whereas during M-phase both CDK sites, S23 and S29, are phosphorylated. Immunofluorescence microscopy revealed that the mitotic phosphorylation of RPA2 starts at the onset of mitosis, and dephosphorylation occurs during late cytokinesis. In mitotic cells treated with ionizing radiation (IR), we observed a rapid hyperphosphorylation of RPA2 in addition to its mitotic phosphorylation at S23 and S29, associated with a significant change in the subcellular localization of RPA. Our data also indicate that the RPA2 hyperphosphorylation in response to IR is facilitated by the activity of both ATM and DNA-PK, and is associated with activation of the Chk2 pathway.
 ...
PMID:Ionizing radiation-dependent and independent phosphorylation of the 32-kDa subunit of replication protein A during mitosis. 1967 22

This study is the first to investigate the anticancer effect of tricetin in human breast adenocarcinoma MCF-7 cells. Results reveal that tricetin inhibits MCF-7 cells by blocking cell cycle progression in the G2/M phase and inducing apoptosis. Cell cycle blockade is associated with increased activation of ataxia telangiectasia-mutated (ATM). Activation of ATM by tricetin phosphorylated p53 at serine 15, resulting in increased stability of p53 by decreasing p53 and murine double minute-2 (MDM2) interaction. In addition, tricetin-mediated G2/M phase arrest was also associated with decreases in the amounts of cyclin B, cyclin A, cdc2 and cdc25C, and increases in the phosphorylation of Chk2, cdc25C and cdc2. The specific ATM inhibitor caffeine significantly decreased tricetin-mediated G2/M arrest by inhibiting the phosphorylation of p53 (serine 15) and Chk2. Tricetin-induced apoptotic cell death is associated with changes in the expression of Bax and Bak, decreasing levels of Bcl-2 and Bcl-X(L), and subsequently triggering the mitochondrial apoptotic pathway. In addition, pretreatment of cells with caspase-9 inhibitor blocked tricetin-induced apoptosis, indicating that caspase-9 activation is involved in tricetin-mediated MCF-7 cell apoptosis. These findings suggest that tricetin may be a promising chemopreventive agent against human breast cancer.
 ...
PMID:Tricetin, a dietary flavonoid, inhibits proliferation of human breast adenocarcinoma mcf-7 cells by blocking cell cycle progression and inducing apoptosis. 1970 44

The role of the mismatch repair (MMR) system in correcting base-base mismatches is well established; its involvement in the response to DNA double strand breaks, however, is less clear. We investigated the influence of the essential component of MMR, the hMLH1 protein, on the cellular response to DNA-double strand breaks induced by treatment with SN-38, the active metabolite of topoisomerase I inhibitor irinotecan, in a strictly isogenic cell system (p53(wt), hMLH1(+)/p53(wt), hMLH1(-)). By using hMLH1 expressing clones or cells transduced with the hMLH1-expressing adenovirus as well as siRNA technology, we show that in response to SN-38-induced DNA damage the MMR proficient (MMR(+)) cells make: (i) a stronger G2/M arrest, (ii) a subsequent longer tetraploid G1 arrest, (iii) a stronger activation of Chk1 and Chk2 kinases than the MMR deficient (MMR(-)) counterparts. Both Cdk2 and Cdk4 kinases contribute to the basal tetraploid G1 arrest in MMR(+) and MMR(-) cells. Although the Chk1 kinase is involved in the G2/M arrest, neither Chk1 nor Chk2 are involved in the enhancement of the tetraploid G1 arrest. The long-lasting tetraploid G1 arrest of MMR(+) cells is associated with their lower clonogenic survival after SN-38 treatment, the abrogation of the tetraploid G1 arrest resulted in their better clonogenic survival. These data show that the stabilization of the tetraploid G1 arrest in response to double strand breaks is a novel function of the MMR system that contributes to the lesser survival of MMR(+) cells.
 ...
PMID:Mismatch repair system decreases cell survival by stabilizing the tetraploid G1 arrest in response to SN-38. 1973 70

Widdrol, an odorous compound extracted from Juniperus chinensis, has been shown to inhibit the in vitro growth of in human cancer cells. This study was conducted on cultured human colon adenocarcinoma HT29 cells to elucidate the possible mechanisms by which widdrol exerts its anti-proliferative activity, which until now has remained poorly understood. It was found that widdrol induces accumulation of sub-G1 phase and arrests in the G1 phase of the cell cycle. Induction of G1 arrest by widdrol was correlated with induction of Chk2, p53 phosphorylation and CDK inhibitor p21 expression as well as inhibition of cyclin E, cyclin-dependent kinase (CDK2) and retinoblastoma protein (pRB). Moreover, mini-chromosome maintenance (MCM) proteins were markedly down-regulated in HT29 cells treated with widdrol. Altogether, these results show widdrol possesses potential anti-cancer activity against colon adenocarcinoma cells by inhibiting their proliferation and inducing cell cycle G1 arrest.
 ...
PMID:Widdrol induces cell cycle arrest, associated with MCM down-regulation, in human colon adenocarcinoma cells. 1982 35

Emodin--a major component of Rheum palmatum L.-exerts antiproliferative effects in cancer cells that are regulated by different signaling pathways. Hepatocellular carcinoma has high-incidence rates and is associated with poor prognosis and high mortality rates. This study was designed to evaluate the effects of emodin on human hepatocarcinoma cell viability and investigate its mechanisms of action in Huh7, Hep3B, and HepG2 cells. To define the molecular changes associated with this process, expression profiles were compared in emodin-treated hepatoma cells by cDNA microarray hybridization, quantitative RT-PCRs, and Western blot analysis. G2/M phase arrest was observed in all 3 cell lines. Cell cycle regulatory gene analysis showed increased protein levels of cyclin A, cyclin B, Chk2, Cdk2, and P27 in hepatoma cells after time courses of emodin treatment, and Western blot analysis showed decreased protein levels of Cdc25c and P21. Microarray expression profile data and quantitative PCR revealed that 15 representative genes were associated with emodin treatment response in hepatoma cell lines. The RNA expression levels of CYP1A1, CYP1B1, GDF15, SERPINE1, SOS1, RASD1, and MRAS were upregulated and those of NR1H4, PALMD, and TXNIP were downregulated in all three hepatoma cells. Moreover, at 6h after emodin treatment, the levels of GDF15, CYP1A1, CYP1B1, and CYR61 were upregulated. Here, we show that emodin treatment caused G2/M arrest in liver cancer cells and increased the expression levels of various genes both in mRNA and protein level. It is likely that these genes act as biomarkers for hepatocellular carcinoma therapy.
 ...
PMID:Emodin inhibits the growth of hepatoma cells: finding the common anti-cancer pathway using Huh7, Hep3B, and HepG2 cells. 1989 93


<< Previous 1 2 3 4 5 6 Next >>