OBJECTIVETo explore the inhibitory effect of norcantharidin (NCTD) on the expression of DNA replication initiation protein Cdc6 in cancer cells.

METHODSMTT assay was performed to detect the inhibitory effect on different cancer cell lines, including HeLa, HepG2, Jurkat and Ramos cells. The effect of NCTD on Cdc6 protein level was detected by Western blotting, and BrdU incorporation assay was used to evaluate the DNA replication of the cells.

RESULTSNCTD significantly inhibited the proliferation of the cells and caused degradation of Cdc6 protein to result in the inhibition of the DNA replication of the cells shown by BrdU incorporation assay.

CONCLUSIONNCTD can induce the degradation of Cdc6 in cancer cells to produce an anti-cancer effect.

Bridged Bicyclo Compounds, Heterocyclic ; pharmacology ; Cell Cycle Proteins ; metabolism ; Cell Line, Tumor ; DNA Replication ; drug effects ; Humans ; Nuclear Proteins ; metabolism

OBJECTIVETo investigate the effect of NSC348884, a nucleophosmin small molecular inhibitor, on the growth of hepatocellular carcinoma cell line HepG2 and its underlying mechanism.

METHODSAfter HepG2 cells were treated by NSC348884 for 4 days, the effect of HepG2 cells on proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay, the expression variation of nucleophosmin oligomer and monomer was measured using Western blotting, and cell apoptotic rate was detected by flow cytometry.

RESULTSThe proliferation of HepG2 cells was remarkably inhibited by NSC348884 treatment when the drug concentration ranged from 1 micromol/L to 10 micromol/L (P < 0.05), with a 50% inhibiting concentration of 1.4 micromol/L. After treatment for 24 hours, the expression level of nucleophosmin oligomer decreased obviously while that of nucleophosmin monomer increased (both P < 0.05). After treatment by 1 micromol/L and 2 micromol/L NSC348884, the 24-hour apoptotic rates of HepG2 cells were (13.770 +/- 0.335)% and (19.021 +/- 0.237)%, respectively, which were significantly higher than in the control group (6.950 +/- 0.207)% (P < 0. 05).

CONCLUSIONNSC348884 can promote the transformation of nucleophosmin oligomer to monomer and thus inhibit the growth of hepatic carcinoma cell line HepG2 in vitro.

Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Hep G2 Cells ; Humans ; Indoles ; pharmacology ; Nuclear Proteins ; antagonists & inhibitors ; metabolism

OBJECTIVETo investigate antitumor activity and molecular mechanism of deguelin to the human U937 leukaemia cells and to explore the mechanisms regulating cell cycle and nucleoporin 98 (Nup98) and nucleoporin 88 (Nup88) in vitro.

METHODSThe effects of deguelin on the growth of U937 cells were studied by MTT assay, and the cell cycle of U937 cells by a propidium iodide method. The localization of the nuclear pore complex protein Nup98 and Nup88 was checked by immunofluorescence and immunoelectron microscopy. The expressions of Nup98 and Nup88 in U937 cells were checked by flow cytometry (FCM) and Western blot respectively.

RESULTSThe proliferation of U937 cells was significantly inhibited in a time-dose dependent manner in deguelin-treated group with a 24 h IC50 value of 21.61 nmol/L and 36 h IC50 value of 17.07 nmol/L. U937 cells treated with deguelin showed reduction in the percentages of cells in G0/G1, whereas accumulation of cells in S and G2/M phase. The ratio of G1/G0 phase cells were 73.01%, 71.15%, 68.42%, 52.45%, 43.99% and 22.82%, and that of S phase cells were 17.18%, 16.30%, 18.09%, 27.56%, 31.21% and 46.85%, and that of G2/M phase cells were 9.75%, 12.31%, 13.09%, 18.99%, 24.83% and 27.79% at deguelin concentrations of 0, 5, 10, 20, 40, 80 nmol/L respectively. Nup88 and Nup98 were found on both the nuclear and cytoplasmic side of the U937 cells. The expression of Nup98 was up-regulated and Nup88 down-regulated in deguelin treated U937 cells.

CONCLUSIONDeguelin is able to inhibit the proliferation of U937 cells by regulating the cell cycle. The antitumor activity of deguelin was related to up-regulating the expression of Nup98 and down-regulating Nup88 protein.

Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Humans ; Nuclear Pore Complex Proteins ; metabolism ; Rotenone ; analogs & derivatives ; pharmacology ; U937 Cells

This study was aimed to investigate the effect of AG490, a JAK2 inhibitor, on expression of PHLPP and p-Akt in K562. K562 cells were treated with different concentrations of AG490. The proliferation of K562 cells was examined by WST-1 assay and apoptosis of K562 cells was detected by flow cytometry with Annexin V-FITC/PI double staining. The expressions of PHLPP, phosphorate-Akt (p-Akt) and total Akt protein were detected by Western blot. The results indicated that AG490 inhibited the proliferation of K562 cells in concentration-and time-dependent manners, with the IC(50) 338.0 µmol/L in 48 h. AG490 100 µmol/L also induced apoptosis of K562 cells in a time-dependent manner. AG490 100 µmol/L time-dependently down-regulated the protein expression of p-Akt and PHLPP, but without significant effect on expression of total Akt. It is concluded that AG490 can inhibit proliferation and induce apoptosis of K562 cells through down-regulation of p-Akt expression, but inhibiting efficacy of AG490 on K562 proliferation also may be limited due to the down-regulation of p-Akt regulatory protein PHLPP expression.
Cell Proliferation ; drug effects ; Down-Regulation ; Humans ; K562 Cells ; Nuclear Proteins ; metabolism ; Phosphoprotein Phosphatases ; metabolism ; Tyrphostins ; pharmacology

In order to investigate the anti-leukemia effects of gambogic acid (GA) and its relation to the regulation of nucleoporin Nup88 in U937 cells in vitro, the inhibitory effect of GA on the growth of U937 cells was examined by using MTT assay. Apoptosis was detected by Annexin-V FITC/PI double-labeled cytometry. Cell cycle regulation was studied by propidium iodide method. Both flow cytometry (FCM) and RT-PCR were employed to assess the expression of Nup88, and the localization of Nup88 was determined by confocal microscopy. The results indicated that GA had strong inhibitory effect on cell proliferation and apoptosis induction activity in U937 cells in vitro in a time-and dose-dependent manner. The 24-h IC(50) value was (1.019+/-0.134) mg/L. Moreover, GA induced arrest of U937 cells in G(0)/G(1) phase. Over-expression of Nup88 was found in U937 cells, whereas GA could significantly down-regulate both the protein and mRNA levels of Nup88. Nup88 was diffusely distributed between nucleus and cytoplasm and was located at the cytoplasmic side of nuclear rim, and occasionally in cytoplasm. It is suggested that GA exerts its anti-leukemia effects by regulating the expression and distribution of nucleoporin Nup88. It promises to be new agent for the treatment of acute leukemia.
Antineoplastic Agents, Phytogenic/*pharmacology ; Apoptosis/drug effects ; Cell Proliferation/drug effects ; Nuclear Pore Complex Proteins/genetics ; Nuclear Pore Complex Proteins/*metabolism ; RNA, Messenger/genetics ; RNA, Messenger/metabolism ; U937 Cells ; Xanthones/*pharmacology

OBJECTIVETo explore the effect of arsenic trioxide (As2O3) on the growth inhibition of imatinib (IM)-resistant bcr-abl mutant cell lines in vitro.

METHODSCell growth of one IM-sensitive cell line, 32Dp210 and 15 IM-resistant cell lines including T315I and other 14 bcr-abl mutants were detected by MTT assay after treatment with IM and As2O3. The cell lines with 5 frequently observed mutants in CML patients were analyzed for apoptosis by flow cytometry with Annexin V and PI staining as well as the expression of bcr-abl fusion protein, phosphorylated CRKL protein and apoptosis-related proteins by Western blot.

RESULTSThe fifty percent inhibition concentration (IC50) values of As2O3 for 15 IM-resistant cell lines were 2.6-5.3 fold lower than that for IM-sensitive cell line. For the 5 bcr-abl mutants frequently happened in CML patients, As2O3 significantly inhibited the expression of bcr-abl fusion protein and phosphorylated CRKL and induced apoptosis in a dose-dependent manner as compared with that for 32Dp210. Coincidently, the cell apoptosis was induced through caspase-3, 8 and 9 pathways.

CONCLUSIONAs2O3 remarkably inhibits cell growth and induces apoptosis of IM-resistant bcr-abl mutant cell lines in vitro, suggesting that it might be a potential therapeutic agent for IM-resistant CML patients.

Adaptor Proteins, Signal Transducing ; metabolism ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Benzamides ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drug Resistance, Neoplasm ; Fusion Proteins, bcr-abl ; genetics ; metabolism ; Humans ; Imatinib Mesylate ; Mutation ; Nuclear Proteins ; metabolism ; Oxides ; pharmacology ; Piperazines ; pharmacology ; Pyrimidines ; pharmacology

OBJECTIVETo study the roles of DNA dependent protein kinase (DNA-PK)in silica-induced cell cycle changes and expressions of CyclinE and CDK2 in human embryo lung fibroblasts (HELF).

METHODSThe expressions of Ku80 and DNA-PKcs proteins were inhibited by siRNA plasmids, respectively. Flow cytometry was used to detect the distributions of cell cycle and western blot assay was used to determine the expression levels of CyclinE and CDK2 after cells were exposed to 200 microg/ml silica for 0, 3, 6, 12, 24 h.

RESULTSThe proportion of G1 phases in negative control cells decreased from 83.53% +/- 2.24% to 69.11% +/- 3.12% after exposure to silica; the proportion of G1 phases in H-Ku80 and H-PKcs cells exposed to silica decreased from 85.16% +/- 3.73% to 59.92% +/- 3.31% and from 75.06% +/- 2.23% to 58.32% +/- 1.35%, respectively (P < 0.05). The exposure to silica resulted in the increasing protein expression levels of CyclinE and CDK2 in negative control cells, and the expression levels of CyclinE were obviously suppressed in H-Ku80 and H-PKcs as compared with control cells. However, the expression level of CDK2 protein did not change significantly.

CONCLUSIONDNA-PK might play a role in silica-induced alternations of cell cycle and regulate silica-induced overexpression of CyclinE in human embryo lung fibroblasts.

Cell Cycle ; drug effects ; Cells, Cultured ; Cyclin E ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; DNA-Activated Protein Kinase ; genetics ; metabolism ; Fibroblasts ; cytology ; drug effects ; metabolism ; Humans ; Lung ; cytology ; Nuclear Proteins ; genetics ; metabolism ; Oncogene Proteins ; metabolism ; Silicon Dioxide ; pharmacology

OBJECTIVETo investigate arsenic trioxide (As(2)O(3))-induced apoptosis and the effects on cell nuclear matrix related protein promyelocytic leukaemia (PML).

METHODSHepG2 cells were cultured in MEM medium and treated with 0.5, 2, 5 and 10 micro mol/L As(2)O(3) for either 24 h or 96 h at each concentration. In situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladders were used to detect apoptosis. Confocal microscopy and Western blotting were used to observe the expression of PML.

RESULTSThe growth rates of HepG2 cells were slower in the As(2)O(3) treated than the untreated control group. DNA ladder and TUNEL positive apoptotic cells could be detected in As(2)O(3) treated groups. The expression of PML decreased in HepG2 cells with 2 micro mol/L As(2)O(3) treatment. Confocal images demonstrated that the expression of PML protein in HepG2 cell nuclei decreased after treatment with 2 micro mol/L As(2)O(3), and micropunctates characteristic of PML protein in HepG2 cell nuclei disappeared after treatment with 5 micro mol/L As(2)O(3).

CONCLUSIONSOur results show that arsenic trioxide can significantly inhibit the growth of HepG2 cells in vitro. As(2)O(3) induces apoptosis in HepG2 tumor cells in a time and concentration dependent manner. As(2)O(3) may degrade the PML protein in HepG2 cell nuclei. The decreased expression of PML in As(2)O(3) treated tumor cells is most likely to be caused by apoptosis. Nuclear matrix associated protein PML could be the target of As(2)O(3) therapy.

Antineoplastic Agents ; pharmacology ; Arsenicals ; pharmacology ; Humans ; Neoplasm Proteins ; metabolism ; Nuclear Matrix ; drug effects ; metabolism ; Nuclear Proteins ; Oxides ; pharmacology ; Promyelocytic Leukemia Protein ; Transcription Factors ; metabolism ; Tumor Cells, Cultured ; Tumor Suppressor Proteins

OBJECTIVETo investigate the anti-atherosclerosis mechanism of Astragalus mongholicus polysaccharides (APS) by examining its effect on gene expression profiles of the dendritic cells (DCs) from healthy donors.

METHODSPeripheral blood DCs from healthy donors were incubated with 200 mg/L APS overnight, and changes in the gene expression profiles were investigated using microarray technique and RT-PCR.

RESULTSCompared with the control cells, APS-treated DCs showed significantly up-regulated expressions of CD36 (0.97 ± 0.23 vs 5.45 ± 1.14) and IL-27 (1.08 ± 0.22 vs 2.97 ± 0.61) and down-regulated expression of expression of IFI16 (0.98 ± 0.18 vs 0.46 ± 0.11).

CONCLUSIONSAPS can promote the maturation and differentiation of DCs by up-regulating CD36 and IL-27 and down-regulating IFI16, and thus positively affects the occurrence and progression of the atherosclerosis.

Astragalus Plant ; chemistry ; CD36 Antigens ; metabolism ; Cell Differentiation ; Dendritic Cells ; drug effects ; Humans ; Interleukins ; metabolism ; Nuclear Proteins ; metabolism ; Phosphoproteins ; metabolism ; Polysaccharides ; pharmacology ; Transcriptome

BACKGROUNDHepatitis B virus (HBV) x protein (HBx) in HepG2 cells causes a moderate decrease in proteolysis activity of the proteasome. A highly conserved Kunitz-type serine protease inhibitor domain within 154 amino acid residues of HBx has been identified. In this study, a peptide chain derived from the Kunitz domain (PKD) was used to study its effect on the cell cycle and apoptosis of HepG2 cells, and investigated the function of PKD on the activities of proteasomes and AAA-ATPase p97, which involves in the ubiquitin-proteasome protein degradation pathway.

METHODSThe PKD peptide (Phe-Val-Leu-Gly-Gly-Cys-Arg-His-Lys) was chemically synthesized. MTT assays were used to determine the effects of PKD on HepG2 cell growth. Mouse anti-p97 antibody was developed for Western blotting to detect the expression of p97. ATPase activity of proteasomes was measured using a colorimetric assay. Peptidase activities of proteasomes were analyzed with various peptidase-specific fluorogenic peptide substrates. Flow cytometry was used to determinate cell cycle phase and apoptosis.

RESULTSViability of HepG2 cells decreased in a PKD-dose-dependent manner. Cells exhibited significant cytotoxicity in the presence of 15 mmol/L of PKD. Western blotting analysis showed that expression of p97 was suppressed in HepG2 cells treated with PKD compared to untreated cells. The ATPase activity of proteasomes from immunoprecipitates of HepG2 cells pretreated with PKD was apparently decreased. Chymotryptic activity of proteasomes in HepG2 cells was significantly inhibited by 10 mmol/L PKD; tryptic activity and peptidylglutamyl peptide hydrolase activity of proteasomes were less inhibited by PKD than chymotryptic activity. The cell cycle phase of HepG2 cells treated with PKD for 36 hours was blocked largely at the G(0)-G(1) phase, while untreated control cells were mainly in S phase. PKD also significantly induced apoptosis.

CONCLUSIONSThe peptide derived from Kunitz domain of HBx protein induces HepG2 cell growth arrest and apoptosis, which may result from down-regulation of p97 expression, and decrease of both the ATPase and chymotryptic activities of proteasomes.

Adenosine Triphosphatases ; metabolism ; Animals ; Apoptosis ; drug effects ; Blotting, Western ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Enzyme Activation ; drug effects ; Humans ; Lipopeptides ; chemistry ; pharmacology ; Mice ; Nuclear Proteins ; metabolism ; Trans-Activators ; chemistry ; Viral Regulatory and Accessory Proteins ; chemistry