Animals ; Cells, Cultured ; DNA ; analysis ; Flow Cytometry ; methods ; Fluorescence ; G1 Phase ; Resting Phase, Cell Cycle

Drug resistance is an important character of leukemic stem cells. To explore the mechanism of the chemotherapy resistance of N-cadherin positive leukemia cells, the quiescent state of N-cadherin positive leukemia cells was determined by flow cytometry and the relationship of G(0) phase cell ratio with the chemotherapy resistance was analyzed. After KG1a cells were induced to enter cell cycle, the G(0) phase cell ratio and the sensitivity of cells to VP16 were determined. Finally the quiescent state and drug resistance properties of KG1a cells were determined after inhibiting N-cadherin-mediated cell-cell interaction by EGTA treatment. The results showed that the G(0) phase cell ratio in N-cadherin positive KG1a cells was higher than that in N-cadherin negative KG1a cells. After KG1a cells were induced to enter cell cycle, the G(0) phase cell ratio was decreased significantly and the sensitivity of KG1a cells to VP16 increased. Following EGTA treatment for 24 hours, the G(0) phase cell ratio decreased and the drug-sensitivity was enhanced significantly. It is concluded that N-cadherin-mediated adhesion keeps N-cadherin positive leukemia cells in quiescent state of G(0) phase, thus protect these leukemia cells against VP16 chemotherapy.
Antigens, CD ; metabolism ; Apoptosis ; drug effects ; Cadherins ; metabolism ; Cell Line, Tumor ; Etoposide ; pharmacology ; therapeutic use ; Flow Cytometry ; Humans ; Leukemia, Myeloid, Acute ; drug therapy ; Resting Phase, Cell Cycle ; drug effects

OBJECTIVETo explore the influence of different nutritional support routes on the intestinal mucosal epithelial cell cycle in burned rats.

METHODSSixty-six Wistar rats inflicted with 30% TBSA III degree burns on the back were employed as the model and were randomly divided into enteral feeding group (EF) and intravenously parenteral nutrition group (PN). Equal volume of nutritional support fluid containing predetermined equal amount of calories and nitrogen was applied via feeding or intravenously infusion through external jugular vein. The indices were observed on 6, 12, 24, 48 and 72 postburn hours (PBHs) with the reference to those in 6 normal rats. The intestinal epithelial cell cycle in jejunal and ileal mucous membrane was analyzed by flow cytometry. Western blotting method was employed in the examination of the expression of cyclin D1, E and that of cyclin dependent kinase (CDK)2 and CDK4.

RESULTS(1) lntestinal mucosal epithelial G0/G1 ratio in jejunum in EF group was significantly lower than that in PN group at 72 PBHs (P < 0.05). While the ratio in ileum in EF was obviously higher than that in PN groups at 6, 12, 48 and 72 PBHs (P < 0.05). (2) The cell percentage of S phase in EF group was evidently higher than that in PN group (P < 0.05 - 0.01) at 48 and 72 PBHs. (3) Intestinal mucosal cyclin D1 expression increased significantly in EF group at 24 PBHs and in PN group at 48 PBHs (P < 0.05) and which in EF group was obviously higher than that in PN group at 72 PBHs (P < 0.05). (4) The expression of the intestinal mucosal cyclin E in EF group at 72 PBHs was evidently higher than the control value and that in PN group (P < 0.05). (5) The expression of CDK2 exhibited no obvious difference among PN,EF and control group (P < 0.05). The CDK4 expression in EF group increased obviously at 72 PBHs (P < 0.05).

CONCLUSIONEarly postburn enteral feeding was beneficial to the progression of intestinal mucosal epithelial cell cycle and to the repairing and renovation of injured intestinal mucosal membrane. Cyclin and CDK might be important in the modulation of the intestinal mucosal epithelial cell cycle.

Animals ; Burns ; metabolism ; pathology ; CDC2-CDC28 Kinases ; Cell Cycle ; physiology ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 2 ; Cyclin-Dependent Kinase 4 ; Cyclin-Dependent Kinases ; metabolism ; Disease Models, Animal ; Enteral Nutrition ; Female ; G1 Phase ; physiology ; Intestinal Mucosa ; metabolism ; pathology ; Male ; Protein-Serine-Threonine Kinases ; metabolism ; Proto-Oncogene Proteins ; Rats ; Rats, Wistar ; Resting Phase, Cell Cycle ; physiology ; S Phase ; physiology

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

OBJECTIVETo study the inhibitory effects of ciglitazone, a synthetic ligand of peroxisome proliferator-activated receptors (PPAR), on human lung cancer growth in vitro and in vivo and its mechanisms.

METHODSHuman lung cancer A549 cells cultured in vitro were treated with different concentrations of ciglitazone. The proliferative activity and cell cycle of A549 cells were determined by MTT assay and flow cytometry. Expression of PPARgamma protein was detected by Western blot. A549 cells (1 x 10(6) cells/nude mouse) were inoculated subcutaneously into nude mice, which were randomly divided into two groups, 10 in each: control group (group A) and ciglitazone treated group (group B). When the tumors grew to a size with diameter around 1 cm, ciglitazone 100 microl (100 micromol/L) was intratumorally injected every other day in group B mice. A total of 15 injections were given. Mice in group A were similarly treated with normal saline. One month later, tumors were excised and weighed. Expression of cyclin D1 and p21 protein were detected by immunohistochemistry and Western blot.

RESULTSGrowth of A549 cells was significantly inhibited in group B in a dose-dependent and time-dependent fashion as compared with that in group A. Most of the ciglitazone-treated cells arrested in G(1)/G(0) phase and the expression of PPARgamma protein was markedly up-regulated. The tumor weights in group A was (2.79 +/- 0.33) g and that in group B was (1.51 +/- 0.40) g, with an inhibition rate of 47.0%. The expression level of cyclin D1 in group A was significantly higher than that in group B, while the expression level of p21 protein in group A was significantly lower than that in group B.

CONCLUSIONCiglitazone can effectively inhibit the growth of human lung cancer A549 and induce its differentiation by cell cycle arrest via PPARgamma activation.

Animals ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Dose-Response Relationship, Drug ; Female ; G1 Phase ; Gene Expression Regulation, Neoplastic ; Humans ; Lung Neoplasms ; drug therapy ; metabolism ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; PPAR gamma ; metabolism ; Random Allocation ; Resting Phase, Cell Cycle ; Thiazolidinediones ; pharmacology ; therapeutic use ; Time Factors

OBJECTIVETo explore the effect of p21(WAF1) on the proliferation and the sensitivity to Vp16 of leukemia cell line K562.

METHODSA p21(WAF1) retroviral expression vector pLXSN-p21(WAF1) was constructed by FuGENE 6, pLXSN-p21(WAF1) and pLXSN-neo, and transfected into p21(WAF1) defect leukemia cell line K562. After selected with G418, K562-p21(WAF1) cell clones that stably expressed p21(WAF1) were isolated. The ectopic expressions of p21(WAF1) mRNA and protein in K562-p21(WAF1) were identified by RT-PCR and Western b1ot. The cell growth rate was tested by trypan blue dye, the cell cycle by FCM and the sensitivity to Vpl6 by cell count and MTT assay.

RESULTSThe expression of p21(WAF1) protein and mRNA could be detected in K562-p21(WAF1) cells. A strong inhibition of cell proliferation was observed in K562-p21(WAF1) cell as compared with that of the control. The cell number in G(0)/G(1) phase was remarkably increased. The sensitivity to Vpl6 decreased, the IC (50) of K562-neo cells was (56.4 +/- 6.5) microgram/ml, and that of K562-p21(WAF1) cells was (131.0 +/- 8.7) microgram/ml (P < 0.01).

CONCLUSIONp21(WAF1) can inhibit the proliferation of leukemia cell and decrease its sensitivity to Vp16.

Antineoplastic Agents, Phytogenic ; pharmacology ; Blotting, Western ; Cell Division ; drug effects ; Cell Survival ; drug effects ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; genetics ; metabolism ; physiology ; Dose-Response Relationship, Drug ; Etoposide ; pharmacology ; G1 Phase ; drug effects ; Gene Expression ; Humans ; K562 Cells ; cytology ; drug effects ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Resting Phase, Cell Cycle ; drug effects ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors

AIMTo evaluate the antiproliferative activity of contragestazol (DL111-IT) on the human prostate cancer cell line PC3 in vitro and in vivo and to elucidate its potential molecular mechanisms.

METHODSThe cell killing ability of DL111-IT was measured by the 3-(4,5-dimethylthia-zol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent assay method and the tumor xenograft model. The cell cycle was analyzed by flow cytometry and protein expression, including retinoblastoma (pRb), cyclin-dependent kinase 4 (CDK4) and cyclin D1, was detected by Western blotting.

RESULTSDL111-IT exhibited high efficiency on cell growth inhibition of the human androgen-independent prostate cancer cell line PC3. The drug concentration that yielded 50% cell inhibition (IC50 value) was 9.9 mg/mL. In the PC3 tumor xenograft study, DL111-IT (1.25 mg/kg-20.0 mg/kg) given once a day for 10 days significantly inhibited tumor growth, with the inhibition rate ranging from 21% to 50%. Flow cytometric analysis indicated that DL111-IT could cause G1 arrest in the PC3 cell line, but not apoptosis. DL111-IT enhanced pRb expression and down-regulated CDK4 and cyclin D1 expression, suggesting that cell cycle regulation might contribute to the anticancer property of DL111-IT.

CONCLUSIONDL111-IT inhibits the proliferation of human androgen-independent prostate cancer cell line PC3 in vitro and in vivo by a cell cycle regulation pathway.

Androgens ; pharmacology ; Animals ; Cell Division ; drug effects ; Cell Line, Tumor ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Dose-Response Relationship, Drug ; Female ; G1 Phase ; drug effects ; Humans ; Immunosuppressive Agents ; pharmacology ; In Vitro Techniques ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Prostatic Neoplasms ; drug therapy ; pathology ; Resting Phase, Cell Cycle ; drug effects ; Retinoblastoma Protein ; metabolism ; Transplantation, Heterologous ; Triazoles ; pharmacology

The effects of over-expression of testis-specific expressed gene 1 (TSEG-1) on the viability and apoptosis of cultured spermatogonial GC-1spg cells were investigated, and the immortal spermatogonial cell line GC-1spg (CRL-2053™) was obtained as the cell model in order to explore the function of TSEG-1. We transfected the eukaryotic vector of TSEG-1, named as pEGFP-TSEG-1 into cultured spermatogonial GC-1spg cells. Over-expression of TSEG-1 inhibited the proliferation of GC-1spg cells, and arrested cell cycle slightly at G0/G1 phase. Transfection of TSEG-1 attenuated the transcript levels of Ki-67, PCNA and cyclin D1. In addition, over-expression of TSEG-1 induced early and late apoptosis, and reduced the mitochondrial membrane potential of GC-1spg cells. Moreover, transfection of TSEG-1 significantly enhanced the ratio of Bax/Bcl-2 and transcript levels of caspase 9, and decreased the expression of Fas and caspase 8 in GC-1spg cells. These results indicated over-expression of TSEG-1 suppresses the proliferation and induces the apoptosis of GC-1spg cells, which establishes a basis for further study on the function of TSEG-1.
Animals ; Caspase 8 ; biosynthesis ; genetics ; Cell Line ; Cyclin D1 ; biosynthesis ; genetics ; G1 Phase ; physiology ; Histones ; genetics ; metabolism ; Ki-67 Antigen ; biosynthesis ; genetics ; Male ; Mice ; Proliferating Cell Nuclear Antigen ; biosynthesis ; genetics ; Resting Phase, Cell Cycle ; physiology ; Spermatogonia ; cytology ; metabolism ; bcl-2-Associated X Protein ; biosynthesis ; genetics

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

OBJECTIVE: To explore the effect of LRRC4, a glioma suppressive gene, on blocking U251 cells in G0/G1 by MAPK signaling pathway. METHODS: LRRC4 was transfected into U251 cells, and at 24 hour of post-transfection, cells were split at a 1:3 dilution, challenged with 500 microg /mL G418 and formed a stable transfected clone pool. RT-PCR, Northern blot and Western blot were used to identify the stable transfectants. ERK, JNK and P38 expression changes were analyzed by Western blot. FACS analysis, Luciferase reporter gene assay and Western blot were used to detect the cell cycle and cyclin D1. RESULTS: LRRC4 down-regulated the expression of phosphorylated ERK2 and up-regulated the expression of total protein JNK2 (a key molecule of MAPK signaling pathway) and phosphorylated c-Jun. LRRC4 decreased the expression of mutation P53, cyclin D1 activation and its expression. U251 cells were blocked in G0/G1 by LRRC4. CONCLUSION LRRC4 can decrease JNK2, up-regulate the phosphoralated c-Jun, down-regulate mutant P53 and cyclin D1, and therefore block U251 cells in G0/G1.
Blotting, Northern ; Blotting, Western ; Cell Line, Tumor ; Cyclin D1 ; metabolism ; Flow Cytometry ; G1 Phase ; genetics ; physiology ; Glioma ; genetics ; metabolism ; pathology ; Humans ; Luciferases ; genetics ; metabolism ; MAP Kinase Signaling System ; genetics ; physiology ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Nerve Tissue Proteins ; genetics ; metabolism ; physiology ; RNA, Messenger ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Resting Phase, Cell Cycle ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection