OBJECTIVETo study the effect of all-trans retinoic acid (ATRA) on U937 cell growth and its mechanism.

METHODSCell cycle was detected by flow cytometry (FCM), expressions of cell cycle associated protein and the p27 related protein were detected by Western blot. The binding of P27 and Skp2 was detected by immunoprecipitation.

RESULTSFCM displayed that ATRA could inhibit the proliferation of U937 cells. At 72 h on 1 micromol/L ATRA treatment, 72% of the cells were arrested at G0/G1 phase. Western blot displayed that ATRA could decrease the expression of cyclin A, up-regulate the expression of p21 and p27, and down-regulate the expression of p27 related proteins Skp2. p27 could bind with Skp2 in U937 cells as detected by immunoprecipitation.

CONCLUSIONATRA may arrest the proliferation of U937 cells through the reduction of Skp2 expression, and finally the induction of the accumulation of p27.

Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Humans ; S-Phase Kinase-Associated Proteins ; metabolism ; Tretinoin ; pharmacology ; U937 Cells

AIMTo observe the cytotoxic effect of the organophosphate insecticide malathion in the reproductive tissues of the earthworms, Eisenia foetida.

METHODSWorms were nourished in soil treated with malathion at single sub-lethal doses of 0, 80, 150, 300 and 600 mg/kg soil. (LD50=880 mg/kg soil) and evaluated on days 1, 5, 15 and 30 after exposure. The body weights were recorded and male reproductive organs evaluated.

RESULTSMalathion-treated animals showed a significant reduction in body weight in a dose-dependent manner. Malathion treatment modified the disposition of spermatozoa in the basal epithelium of the spermatheca. The Br-deoxyuridine test showed a significant rise in cells in phase S on days 5 and 15. Also, a higher percentage of spermatogonia with fragmented DNA were observed by means of the TdT-mediated dUTP nick-end labeling (TUNEL) technique in the spermatheca of treated animals.

CONCLUSIONTreatment with malathion decreased the body weight and the spermatic viability in spermatheca, altering the cell proliferation and modifying the DNA structure of spermatogonia.

Animals ; Body Weight ; drug effects ; DNA Fragmentation ; Dose-Response Relationship, Drug ; In Situ Nick-End Labeling ; Malathion ; adverse effects ; Male ; Oligochaeta ; drug effects ; Reproduction ; drug effects ; S Phase ; drug effects ; genetics ; Spermatozoa ; drug effects ; Time Factors

OBJECTIVETo investigate the effects of the resveratrol on proliferation and gap-junctional intercellular communication (GJIC) in human liver cancer cell line HepG2.

METHODSMTT assay was used to observe the effects of resveratrol on HepG2 cell growth, and the distribution of cell cycles was detected with flow cytometry (FCM). The effects of resveratrol on GJIC of HepG2 cells labeled with 5'-CFDA/AM was examined with fluorescence redistribution after photobleaching (FRAP) and confocal microscope.

RESULTSThe results of MTT assay indicated that the proliferation of HepG2 cells was significantly inhibited by resveratrol in a time- and dose-dependent manner. Resveratrol could arrest HepG2 cell growth in S phase, inhibit DNA synthesis and induce cell apoptosis. Furthermore, the levels of GJIC increased sharply after resveratrol treatment of the cells.

CONCLUSIONResveratrol is capable of inhibiting HepG2 cell proliferation, causing cell growth arrest at S phase and inducing cell apoptosis. Increased GJIC level contributes to the effect of resveratrol in HepG2 cell proliferation inhibition and its cancer chemopreventive activity.

Antineoplastic Agents, Phytogenic ; pharmacology ; Carcinoma, Hepatocellular ; pathology ; physiopathology ; Cell Communication ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Gap Junctions ; drug effects ; Humans ; Liver Neoplasms ; pathology ; physiopathology ; S Phase ; drug effects ; Stilbenes ; pharmacology

OBJECTIVETo investigate the effect of S-phase kinase-associated protein 2 antisense oligodeoxynucleotide (Skp2 ASODN) on the growth and proliferation of gastric carcinoma SGC-7901 cells and its mechanism.

METHODSThe Skp2 oligodeoxynucleotides (ODNs) were embedded in cationic liposome Lipofectamine 2000 reagent and transfected into SGC-7901 cells. The cell growth and proliferation were observed with light microscopy and MTT assay. Cell cycle was measured by flow cytometry. The expression levels of Skp2 and p27 mRNA were detected by reverse transcription-polymerase chain reaction. The expression levels of Skp2 protein and its substrate p27 protein were detected by Western blot.

RESULTAfter treatment with Skp2 ASODN, the growth and proliferation of SGC-7901 cells were inhibited in a dose-dependent manner with a peak value at 48 h. The inhibition rate of 200 nmol/L group at 48 h was 42.4 % (P<0.01). In cell cycle study the percentage of S phase cells in 200 nmol/L group was significantly higher than that in normal control group (P<0.05). Both Skp2 mRNA and its protein levels in 200 nmol/L group were significantly lower than those in control group and in Skp2 nonsense oligodeoxynucleotide (Skp2 NSODN) group (P<0.05). However, p27 mRNA level remained unchanged although its protein level was significantly higher than that in control group and NSODN group (P<0.05).

CONCLUSIONSkp2 ASODN can inhibit the growth and proliferation of SGC-7901 cells, which may be mediated by interfering with ubiquitin-proteosome pathway and cell cycle regulation.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Humans ; Oligodeoxyribonucleotides, Antisense ; genetics ; pharmacology ; S-Phase Kinase-Associated Proteins ; genetics ; pharmacology ; Stomach Neoplasms ; pathology ; Transfection

OBJECTIVETo investigate the biological activity and molecular mechanism of interferon alpha (IFNalpha) on human myeloma cell line Sko-007.

METHODSThe effect of IFNalpha on the growth of Sko-007 cells was measured by MTT assay. Cells cycle distribution and the expression of two IL-6 receptor chains (IL-6R and gp130) on Sko-007 cell surface in the absence or presence of IFNalpha were monitored by FACS analysis. The activation state of protein kinase ERK, which is involved in Ras/MAPK signal transduction pathway mediating cell survival and proliferation, and the expression of anti-apoptotic Bcl-2 family proteins-Bcl-2, Bcl-x(L) and Mcl-1 in Sko-007 cells with or without IFNalpha were determined by immunoblot assay.

RESULTIFNalpha arrested Sko-007 cell cycle progression. After stimulation with IFNalpha, an obvious increase in G(0)/G(1) phase (41.1%-->84.1%) and decrease in S phase (57.1%-->13.3%) of Sko-007 cell cycle distribution can be observed. Moreover, the proliferation of Sko-007 cells was dramatically inhibited in the presence of IFNalpha, with a maximal inhibitory rate up to 88%. In addition, the expression of gp130 on cell surface, the activation of protein kinase ERK and the expression of Bcl-2 and Bcl-x(L) were all down-regualted in IFNalpha-stimulated Sko-007 cells.

CONCLUSIONThe inhibitory effect of IFNalpha on the proliferation of Sko-007 cells was mediated by gp130 down-regulation, degradation of Bcl-2 family anti-apoptotic proteins and inhibition of ERK activation.

Antigens, CD ; drug effects ; metabolism ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Cytokine Receptor gp130 ; Dose-Response Relationship, Drug ; Down-Regulation ; Enzyme Activation ; drug effects ; G1 Phase ; drug effects ; Humans ; Immunoblotting ; Interferon-alpha ; pharmacology ; Membrane Glycoproteins ; drug effects ; metabolism ; Mitogen-Activated Protein Kinases ; metabolism ; Multiple Myeloma ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Receptors, Interleukin-6 ; drug effects ; metabolism ; Resting Phase, Cell Cycle ; drug effects ; S Phase ; drug effects ; Tumor Cells, Cultured ; drug effects ; metabolism ; bcl-X Protein

AIMTo study the effects of 9-cis-retinoic acid (9-cis-RA) on cell cycle and expression of cyclin D1 and cdk4 in lung cancer cells.

METHODS9-cis-RA (1 x 10(-6) mol.L-1) was used to treat lung cancer cells for 24 h; Flow cytometry (FCM) was used to detect the percent of G0/G1 phase and S phase cells of three groups including blank control, DMSO control and 9-cis-RA groups; RT-PCR was used to analyze the expression changes of cyclin D1 and cdk4 before and after treatment with 9-cis-RA in lung cancer cells.

RESULTSThe percent of G0/G1 phase cells of 9-cis-RA groups was significantly higher than that of the control groups (P < 0.01 or P < 0.05) and the percent of S phase cells of 9-cis-RA groups was lower than that of the control groups (P < 0.01 or P < 0.05); the expression of cyclin D1 of PG, SPC-A1 and L78 cells was decreased (P < 0.01) and the expression of cdk4 of PG, A549 and L78 cells was also decreased (P < 0.01) after treatment with 9-cis-RA.

CONCLUSIONMost of the proliferation and the expression of cyclin D1 and cdk4 of PG, A549, SPC-A1 and L78 were inhibited by 9-cis-RA.

Adenocarcinoma ; metabolism ; pathology ; Antineoplastic Agents ; pharmacology ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Cell Division ; drug effects ; Cell Line, Tumor ; Cyclin D1 ; biosynthesis ; Cyclin-Dependent Kinase 4 ; Cyclin-Dependent Kinases ; biosynthesis ; G1 Phase ; drug effects ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; Resting Phase, Cell Cycle ; drug effects ; S Phase ; drug effects ; Tretinoin ; pharmacology

Icaritin, a prenylflavonoid derivative from Epimedium Genus, has been shown to exhibit many pharmacological and biological activities. However, the function and the underlying mechanisms of icaritin in human non-small cell lung cancer have not been fully elucidated. The purpose of this study was to investigate the anticancer effects of icaritin on A549 cells and explore the underlying molecular mechanism. The cell viability after icaritin treatment was tested by MTT assay. The cell cycle distribution, apoptosis and reactive oxygen species (ROS) levels were analyzed by flow cytometry. The mRNA and protein expression levels of the genes involved in proliferation and apoptosis were respectively detected by RT-PCR and Western blotting. The results demonstrated that icaritin induced cell cycle arrest at S phase, and down-regulated the expression levels of S regulatory proteins such as Cyclin A and CDK2. Icaritin also induced cell apoptosis characterized by positive Hoechst 33258 staining, accumulation of the Annexin V-positive cells, increased ROS level and alteration in Bcl-2 family proteins expression. Moreover, icaritin induced sustained phosphorylation of ERK and p38 MAPK. These findings suggested that icaritin might be a new potent inhibitor by inducing S phase arrest and apoptosis in human lung carcinoma A549 cells.
Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Flavonoids ; pharmacology ; Humans ; Lung Neoplasms ; drug therapy ; metabolism ; pathology ; MAP Kinase Signaling System ; drug effects ; Neoplasm Proteins ; biosynthesis ; Reactive Oxygen Species ; metabolism ; S Phase Cell Cycle Checkpoints ; drug effects

OBJECTIVETo study the enhancing effect of isoflavonoid genistein in irradiation (IR) on prostate DU145 cancer cells.

METHODSProstate cancer cell line DU145 was used in this experiment. Clonogenic assay was applied to compare the survival fractions of DU145 cells after treatments with genistein alone and/or graded IR. DNA electrophoresis and TUNEL method were applied to detect cell apoptosis. Cell cycle was observed using flow cytometry and related protein expressions by immunoblotting.

RESULTClonogenic assay demonstrated that genistein, even at low to medium concentrations, enhanced the radiosensitivity of DU145 cells. After treatments with IR and/or genistein for 24 h, apoptosis was mainly seen with genistein at high concentration and was minimally dependent on IR. Apoptosis also occurred after treatments for 72 h with lower concentrations of genistein, especially when combined with IR. While IR or genistein led to a G2/M cell cycle arrest, combination of them could further increase DU145 cells at G2/M phase. This G2/M arrest was largely maintained at 72 h, and accompanied by increasing apoptosis and hyperdiploid cell populations. Cell-cycle related protein analysis disclosed biphasic changes in cyclin B1, less markedly increased cdc-2 and stably elevated p21(cip1) levels with increasing genistein concentrations.

CONCLUSIONGenistein could enhance the radiosensitivity of DU145 prostate cancer cells. The mechanisms might be involved in the increased apoptosis, prolonged cell cycle arrest and impaired damage repair induced by the combined treatment.

Apoptosis ; drug effects ; radiation effects ; CDC2 Protein Kinase ; analysis ; Cell Line, Tumor ; Cell Survival ; drug effects ; radiation effects ; Cyclin B ; analysis ; Cyclin B1 ; G2 Phase ; drug effects ; radiation effects ; Genistein ; pharmacology ; Humans ; Male ; Prostatic Neoplasms ; pathology ; radiotherapy ; Radiation-Sensitizing Agents ; pharmacology ; S Phase ; drug effects ; radiation effects

BACKGROUNDBreast cancer is one of the most common malignancies in women and is highly resistant to chemotherapy. Due to its high tumour selectivity, 3-bromopyruvic acid (3-BrPA), a well-known inhibitor of energy metabolism has been proposed as a specific anticancer agent. The present study determined the effect of 3-BrPA on proliferation, cell cycle and apoptosis in the human breast cancer MCF-7 cell line and other antitumour mechanisms.

METHODSMCF-7 cells were treated with various concentrations of 3-BrPA for 1 - 4 days, and cell growth was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. Marked morphological changes in MCF-7 cells after treatment with 3-BrPA were observed using transmission electron microscopy. The distributions of the cell cycle and apoptosis were analyzed by flow cytometry. Immunohistochemistry was used to indicate the changes in the expression of Bcl-2, c-Myc, and mutant p53.

RESULTS3-BrPA (25 microg/ml) significantly inhibited the proliferation of MCF-7 cells in a time-dependent manner. The MCF-7 cells exposed to 3-BrPA showed the typical morphological characteristics of apoptosis, including karyopycnosis, nuclear condensation and oversize cytoplasmic particles. In addition, flow cytometric assay also showed more apoptotic cells after 3-BrPA stimulation. The cells at the G0 and G1 phases were dramatically decreased while cells at the S and G2/M phases were increased in response to 3-BrPA treatment after 48 hours. Furthermore, 3-BrPA stimulation decreased the expressions of Bcl-2, c-Myc and mutant p53, which were strongly associated with the programmed cell death signal transduction pathway.

CONCLUSION3-BrPA inhibits proliferation, induces S phase and G2/M phase arrest, and promotes apoptosis in MCF-7 cells, which processes might be mediated by the downregulation of the expressions of Bcl-2, c-Myc and mutant p53.

Antineoplastic Agents ; chemistry ; pharmacology ; Apoptosis ; drug effects ; Breast Neoplasms ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Female ; Flow Cytometry ; G2 Phase ; drug effects ; Humans ; Immunohistochemistry ; Molecular Structure ; Pyruvates ; chemistry ; pharmacology ; S Phase ; drug effects

OBJECTIVETo observe the effects of Cinnamyl aldehyde (CA) on NIH3T3 cell cycle and explore the possible mechanism further.

METHODFlowcytometry was used for observing cell cycle distribution. Expressions of proliferation cell nuclear antigen (PCNA) and Cyclin D1 protein in NIH3T3 cells were assessed by immunocytochemistry.

RESULTAfter culture with CA for 24 hours, the percentage of populations of S phase was enhanced by 3% (P < 0.05) and cell proliferation index (PrI, S + G2/M) was increased by 3.5% (P < 0.01) , but G2/M phase had no obvious changes. The expressions of Cyclin D1 and PCNA proteins were improved markly by CA compared with controlgroup (P < 0.01).

CONCLUSIONCA could promote more cells in G0/G1 phase into S phase, which may be related to the regulation of the expressions of PCNA and Cyclin D1.

Acrolein ; analogs & derivatives ; isolation & purification ; pharmacology ; Animals ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cinnamomum ; chemistry ; Cyclin D1 ; metabolism ; Flow Cytometry ; Immunohistochemistry ; Mice ; NIH 3T3 Cells ; Plants, Medicinal ; chemistry ; Proliferating Cell Nuclear Antigen ; metabolism ; S Phase ; drug effects