<b>OBJECTIVEb>To confirm the unscheduled in vivo and in vitro expression models of cyclin B1 in cancer cells so as to study the different profiles of cyclin B1 in G(1)-phase immortal cells under different culture states and culture conditions.

<b>METHODSb>Multiparameter flow cytometry (FCM) was used to correlate the expression of cyclin B1 with the position in cell cycle of immortal cells in vivo and in vitro using the MOLT-4 cell line as control. Cells which belonged to G(1)-phase were sorted by FCM according DNA diploidy, and then the expression of cyclin B1 was examined by confocal microscope to confirm the results. For further analysis, different subgroups in G(1) phase were sorted according to the fluorescent intensity of cyclin E, and then the exact period in G(1) phase when cyclin B1 was expressed, were assayed by Western blot.

<b>RESULTSb>Unscheduled expression of cyclin B1 expressed in G(1)-phase was found not only in synchronized leukemia cells MOLT-4 and in vivo transformed T-7 cells, but also in vivo tumor cells detached from clinical samples. In the synchronized growing cells, cyclin B1 was mainly detected in the early G(1) phase, while in transformed T7 cells, cyclin B1 was mainly detected in the late G(1) phase.

<b>CONCLUSIONb>The limitation of detecting cyclin B1 is due to its unscheduled expression, rending cyclin B1 being detected at different time-spots in the G(1) phase. This phenomenon may be related to the adjustment between the loss of control in cell proliferation and cell apoptosis, thereby leading to tumorigenesis.

Apoptosis ; physiology ; Cell Line, Transformed ; Cyclin B ; biosynthesis ; Cyclin B1 ; Flow Cytometry ; G1 Phase ; physiology ; Humans ; Tumor Cells, Cultured

BACKGROUND: Hypoxia inducible factor-1alpha(HIF-1alpha) is a transcription factor for various target genes that are involved in adapting cells to hypoxia. It promotes cell proliferation and survival via modulation of such cell cycle regulators such as cyclin A1 and cyclin B1 in response to hypoxia. This is associated with local failure of radiotherapy, which renders a poor prognosis for cervical carcinoma. METHODS: Using the tissue histologic sections and a tissue microarray of the archived biopsy and surgical specimens of uterine cervical carcinoma from 57 patients who were treated with radiation therapy alone, we performed immunohistochemical staining for HIF-1alpha and cyclin A1 and B1 to evaluate the correlations between the expressions of these proteins in tumors and the clinicopathologic parameters associated with the prognosis. RESULTS: The large tumor cell nests and invasive front margins of the tumors showed comparatively intense immunoreactivity of HIF-1alpha. There was no significant correlation between the HIF-1alpha, cyclin A1 and cyclin B1 expressions and the clinicopathologic factors. CONCLUSIONS: The HIF-1alpha expression showed marked intra-tumoral heterogeneity. The HIF-1alpha expression is neither a powerful predictor of resistance to radiotherapy nor is it a poor prognostic marker in cervical carcinoma patients who are treated with radiotherapy. The expressions of cyclin A1 and cyclin B1 are neither independently associated with the response of radiation therapy nor are they associated with the prognostic parameters of uterine cervical carcinoma.
Anoxia ; Biopsy ; Cell Cycle ; Cell Proliferation ; Cyclin A ; Cyclin A1 ; Cyclin B ; Cyclin B1 ; Cyclins ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; Population Characteristics ; Prognosis ; Proteins ; Transcription Factors ; Uterine Cervical Neoplasms

PURPOSE: The molecular mechanisms that are responsible for the initiation and progression of breast cancers are largely unknown. This study was to analyze the cyclin B1, cdc2, p53 and p16 tumor suppressor genes in human breast cancer. MATERIALS AND METHODS: To investigate the role of cyclin B1, cdc2, p53 and p16 in the pathogenesis and progression of breast carcinomas, 98 cases of breast cancers were examined by immunohistochemical method. The correlations of cyclin B1, cdc2, p53 and p16 expression with various clinico-pathologic findings were analysed. RESULTS: In the normal breast tissues, cyclin B1, cdc2 and p16 were weakly expressed, while p53 was not expressed. On the other hand, cyclin B1, cdc2, p53 and p16 were overexpressed in breast cancer, showing correlation between the expression of cyclin B1 and cdc2 and breast cancers (p=0.00). The overexpressions of cdc2 and p16 were correlated with an infiltrative tumor border pattern and this was statistically significant (p<0.05). In addition, the overexpression of cdc2 was correlated with histologic high grade carcinomas (p=0.00). CONCLUSION: Cyclin B1 and cdc2 appeared to be involved in the genesis or progression of breast cancers. In addition, the overexpressions of p16 and p53 may play important roles in more aggressive tumor and the overexpression of cdc2 is associated with progression of tumor to a higher grade of breast carcinomas. The deranged overexpressions of cyclin B1, cdc2, p16 and p53 may play an important role in human breast carcinogenesis.
Adult ; Aged ; Breast Neoplasms/*genetics/metabolism/pathology ; Cyclin B/*genetics/metabolism ; Cyclin B1/*genetics/metabolism ; Cyclin-Dependent Kinase Inhibitor p16/*genetics/metabolism ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Middle Aged ; Tumor Suppressor Protein p53/*genetics/metabolism

<b>OBJECTIVEb>To investigate the clinical significance of cyclin B1 expression in adult acute leukemia (AL) patients.

<b>METHODSb>The expression of cyclin B1 and p21 and their cell cycle distribution were measured by flow cytometry in 85 adult patients with de novo AL, 10 continuous complete remission (CCR) AL and 17 normal controls (NC). The mRNAs of cyclin B1, p21 cip1 and proliferation cell nuclear antigen (PCNA) in patients and NCs were measured with semi-quantity reverse transcription polymerase chain reaction (RT-PCR).

<b>RESULTSb>Cyclin B1 protein expression in de novo AL patients was significantly higher than that in NC (P < 0.001). It was higher in relapsed patients than in NC (P < 0.05) but was lower than in de novo AL (P < 0.01). There was no difference between the remission cases and NC (P = 0.21), and between CCR patients and NC (P > 0.05). The cyclin B1 overexpression ratio was higher than that of NC. A negative correlation between the expression levels of cyclin B1 and P21 was observed (r = -0.266, P < 0.05). The cyclin B1 protein expression level was positively correlated with its mRNA level. The expression of cyclin B1 was positively correlated with proliferation index (PI) levels, and with PCNA levels (rPI = 0.7314, rPCNA = 0.7152). Remission rate was higher in high cyclin B1 expression patients than in normal cyclin B1 expression patients (P < 0.01), so did the relapse rate (P < 0.01). Patients with higher cyclin B1 expression had higher survival rate.

<b>CONCLUSIONb>Cyclin B1 was overexpressed and abnormally distributed in cell cycle phases in de novo AL patients. Overexpression of cyclin B1 might be a favorable prognostic factor for patients with AL.

Adolescent ; Adult ; Cell Division ; Cyclin B ; analysis ; Cyclin B1 ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; analysis ; Flow Cytometry ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; mortality ; therapy ; Middle Aged ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; metabolism ; mortality ; therapy ; Prognosis ; Recurrence ; Survival Rate

<b>OBJECTIVEb>To investigate the influence of aerosols on the expression of cyclin B(1), cyclin C and proliferating cell nuclear antigen (PCNA) in wound tissue healing of burned rat models.

<b>METHODSb>Sprague Dawley (SD) rats were inflicted as the deep partial thickness burn models. Rats were randomly divided into experimental group and control group. The experimental group were treated with aerosols. Samples were collected in 1 approximately 10 postburn days. Immunohistochemistry and image analysis methods were conducted to examine the expression of cyclin B(1), cyclin C and PCNA in both experimental and control groups.

<b>RESULTSb>The expression of cyclin C in experimental group was detected in nucleus of skin basal cell on the second postburn day, increased evidently at the fifth days and sustained at high expression level up to the tenth days after treatment. The expression of cyclin C in experimental group was significantly higher than control group (P < 0.05). The expression of PCNA was first observed in skin basal cell nucleus and hair follicle cell nucleus in both experimental and control group on the third postburn day. The expression of PCNA increased evidently at the fifth days in experimental after treatment and that increased evidently at the seventh days in control group, which showed there were lots of active proliferation cell. And the difference of the expression of PCNA between experimental and control group was significant (P < 0.01). The expression of cyclin B(1) was detected in nucleus and cytoplasm of skin basal cell in both groups on the third postburn day, and no difference between the experimental and control group (P > 0.05).

<b>CONCLUSIONSb>Aerosols can up-regulate the expression of cyclin C and PCNA in skin basal cell nucleus. Therefore the aerosols can accelerate wound tissue healing.

Aerosols ; Animals ; Burns ; metabolism ; therapy ; Cyclin B ; biosynthesis ; Cyclin B1 ; Cyclin C ; Cyclins ; biosynthesis ; Disease Models, Animal ; Electric Stimulation Therapy ; methods ; Female ; Proliferating Cell Nuclear Antigen ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Wound Healing ; physiology

BACKGROUND: General anesthetics were known to induce expression of immediate early genes (IEGs), including c-fos and c-jun. However, mechanisms of IEG induction by general anesthetics were not fully understood. METHODS: IEG induction by propofol, a kind of intravenous anesthetics, and signal transduction pathways for propofol-induced IEG expression were investigated in human neuroblastoma cell line IMR32 and CHP134 with Northern and Western blot analysis. RESULTS: Cell viability was significantly decreased in IMR32 and CHP134 treated with increasing concentrations of propofol. IMR32 was more sensitive to propofol-induced cytotoxicity than CHP134. Propofol did not affect the cell cycle profile of IMR32. Expression of cyclin A, cyclin B1, CDK4 and CDK6 was increased in IMR32 by propofol treatment in a time-dependent manner. However, expression of cyclin A and CDK4 was decreased in CHP134. Proliferating cell nuclear antigen (PCNA) was increased in both IMR32 and CHP134 treated with propofol from 6 h to 24 h. c-fos and c-jun were induced by propofol treatment in both cells. Propofol also induced extracellular signal-regulated kinase (ERK) phosphorylation in both cells. Pretreatment of PD98059, an MEK inhibitor, blocked propofol-induced c-fos and c-jun expression.Propofol treatment was decreased nuclear transcription factor-kappa B (NF-kappa B) expression in IMR32, but not in CHP134. CONCLUSIONS: Propofol-induced c-fos expression might be mediated through ERK phosphorylation in both IMR32 and CHP134. Propofol-induced cytotoxicity, changes in expressions of cell cycle regulatory proteins, expression of IEGs, ERK phosphorylation, and NF-kappa B expression were different between IMR32 and CHP134.
Anesthetics, General ; Anesthetics, Intravenous ; Blotting, Western ; Cell Cycle ; Cell Cycle Proteins ; Cell Line ; Cell Survival ; Cyclin A ; Cyclin B1 ; Cyclins ; Flavonoids ; Gene Expression ; Genes, Immediate-Early ; Humans ; Neuroblastoma ; NF-kappa B ; Phosphorylation ; Phosphotransferases ; Proliferating Cell Nuclear Antigen ; Propofol ; Signal Transduction

<b>OBJECTIVEb>To assess the ability of tetrandrine (Tet) to enhance the sensitivity to irradiation and its mechanism in cell lines of human breast cancer p53-mutant MCF-7/ADR, p53-wild-type MCF-7 and human colon carcinoma p53-mutant HT-29 as well as in C26 colorectal carcinoma-bearing BALB/c mice.

<b>METHODSb>MCF-7/ADR, HT-29 and MCF-7 cells were exposed to irradiation in the absence or presence of tetrandrine. The effect of Tet on the cytotoxicity of X-irradiation in these three cells was determined and the effect of tetrandrine on cell cycle arrest induced by irradiation in its absence or presence was studied by flow cytometry. Moreover, mitotic index measurement determined mitosis of cells to enter mitosis. Western blotting was employed to detect cyclin B 1 and Cdc2 proteins in extracts from irradiated or non-irradiated cells of MCF-7/ADR, HT-29 and MCF-7 treated with tetrandrine at various concentrations. Tumor growth delay assay was conducted to determine the radio-sensitization of tetrandrine in vivo.

<b>RESULTSb>Clonogenic assay showed that tetrandrine markedly enhanced the lethal effect of X-rays on p53-mutant MCF-7/ADR and HT-29 cells and the sensitization enhancement ratio (SER) of tetrandrine was 1.51 and 1.63, but its SER was only 1.1 in p53-wt MCF-7 cells. Irradiated p53-mutant MCF-7/ADR and HT-29 cells were only arrested in G2/M phase while MCF-7 cells were arrested in G1 and G2/M phases. Radiation-induced G2 phase arrests were abrogated by tetrandrine in a concentration-dependent manner in MCF-7/ADR and HT-29 cells, whereas redistribution within MCF-7 cell cycle changed slightly. The proportion of cells in M phase increased from 1.3% to 14.7% in MCF-7/ADR cells, and from 1.5% to 13.2% in HT-29 cells, but 2.4% to 7.1% in MCF-7 cells. Furthermore, the levels of cyclin B 1 and Cdc2 expression decreased after X-irradiation in MCF-7/ADR and HT-29 cells, and the mitotic index was also lower. Tet could reverse the decrease and induce the irradiated cells to enter mitosis (M phase). Endosomatic experiment showed that tetrandrine caused tumor growth delay in irradiated mice.

<b>CONCLUSIONb>Tetrandrine boosts the cell killing activity of irradiation both in vitro and in vivo. Tetrandrine is a potent abrogator for G2 checkpoint control and can sensitize the cells to radiation.

Animals ; Benzylisoquinolines ; pharmacology ; CDC2-CDC28 Kinases ; metabolism ; Cell Line, Tumor ; Cyclin B ; metabolism ; Cyclin B1 ; Drug Screening Assays, Antitumor ; G2 Phase ; drug effects ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Radiation Tolerance

<b>AIMb>To investigate the radiosensitizing effect and mechanism of action of staurosporine (STP) in human colon carcinoma HT-29 and breast cancer MCF-7/ADR cells.

<b>METHODSb>The effect of STP on the cytotoxicity of X-ray was determined by clonogenic assay. The effect of STP on cell cycle arrest induced by X irradiation was studied in two cell lines by using flow cytometry, Western Blotting was performed to indicate the changes of cyclin B1 and cdc2 protein levels.

<b>RESULTSb>STP sensitized the two cell lines to X-ray by clonogenic assay. STP potentiated the cytotoxicity of X-ray by 2.10- and 2.09-fold in HT-29 and MCF-7/ADR cells. Flow cytometry assay showed that exposure of HT-29 and MCF-7/ADR cells to X-ray caused cells arrest in G2 phase. The percentage of arrest G2 phase cells were 56% and 52.7%, respectively. The addition of STP after irradiation resulted in a dose-dependent reduction of G2 phase arrest induced by X-ray. Furthermore, the results showed that STP blocked decrease of cyclin B1 expression induced by X-ray, while mitotic index measurement indicated that X-ray-irradiated cells treated with STP entered mitosis. The data suggested that the potentiation of cytotoxicity of X-ray by STP is associated with the suppression of cyclin B1 expression, which result in the abrogation of G2 arrest, before the cells entered into M phase, they had not enough time to repair.

<b>CONCLUSIONb>STP is a potent G2 checkpoint abrogator and markedly enhanced the cytotoxicity of X irradiation in the p53 mutant cancer cells.

Breast Neoplasms ; pathology ; Cyclin B ; biosynthesis ; Cyclin B1 ; Enzyme Inhibitors ; pharmacology ; Female ; G2 Phase ; drug effects ; HT29 Cells ; Humans ; Mitotic Index ; Particle Accelerators ; Radiation Tolerance ; drug effects ; Radiation-Sensitizing Agents ; pharmacology ; Staurosporine ; pharmacology ; Tumor Cells, Cultured

In order to investigate the role and the mechanism of protein tyrosine phosphatase (PTPase) signaling pathway in the regulation of proliferation, cell cycle and apoptosis in lymphoma cells, the effects of sodium orthovanadate, Na(3)VO(4), a specific PTPase inhibitor, were explored on Raji lymphoblast-like cell line by MTT assay and CFU-Raji culture, morphologic observation, DNA gel electrophoresis, FCM and RT-PCR. Results showed that MTT assay and CFU-Raji culture demonstrated that sodium or thovanadate inhibited the growth of Raji cells in a concentration-dependent fashion; morphologic observations showed that Raji cells exhibited cytoplasm shrinkage, cytoplasm membrane blebbing, nuclear fragmentation and chromatin condensation forming crescents along nuclear membrane characteristic of apoptosis in the presence of Na(3)VO(4); DNA gel electrophoresis revealed typical DNA ladder reminiscent of DNA cleavage at internucleosomal sites in Na(3)VO(4) treated cells; FCM and RT-PCR indicated that Na(3)VO(4) intervention increased the fraction of annexin V(+) PI(-) cells, reduced the value of mitochondrial transmembrane potential, induced G(2)/M arrest and down-regulated the expression of Bcl-2 and cyclin B1 at both mRNA and protein level in a concentration-dependent manner. It was concluded that PTPase pathway might be implicated in the regulation of cell proliferation, cell cycle and apoptosis, and PTPase specific inhibitor Na(3)VO(4) could induce Raji cell growth inhibition, G(2)/M arrest and apoptosis via down-regulation of Bcl-2 and cyclin B1, and reduction of mitochondrial transmembrane potential.
Apoptosis ; drug effects ; Cell Division ; drug effects ; Cyclin B ; analysis ; Cyclin B1 ; Enzyme Inhibitors ; pharmacology ; Humans ; Leukocyte Common Antigens ; analysis ; Membrane Potentials ; drug effects ; Mitochondria ; drug effects ; physiology ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; Vanadates ; pharmacology

<b>BACKGROUNDb>Cyclin B1 (CLB1) is necessary for mitotic initiation in mammalian cells and plays important roles in cancer development. Therefore, a potential strategy in cancer therapy is to suppress the activity of CLB1 by delivering antisense constructs of CLB1 into tumor cells. In previous CLB1 studies, antisense constructs with a short half life were often used and these constructs might not persistently inhibit CLB1.

<b>METHODSb>We successfully created a recombinant plasmid encoding the full-length antisense cDNA of mouse cyclin B1 (AS-mCLB1) and transfected this construct to the murine Lewis lung carcinoma (LL/2) and CT-26 colon carcinoma (CT-26) cells. We isolated clones of LL/2 and CT-26 transfectants with stable expression of AS-mCLB1. Reverse transcriptional polymerase chain reaction (RT-PCR) and Western blot were applied to detect the expression of the mRNA and protein levels of CLB1. To further test the efficacy of this strategy in vivo, AS-mCLB1-expressing LL/2 and CT-26 transfectants were implanted into mice.

<b>RESULTSb>We found the expression of the mRNA and protein levels of CLB1 decrease in these transfectants. The inhibition of CLB1 caused prominent G1 arrest, abnormal morphology, retarded cell growth and an increase in apoptosis. In AS-mCLB1-expressing LL/2 and CT-26 transfectants implanted mice, tumorigenicity was effectively suppressed compared with the controls. In addition, the expression of AS-mCLB1 also significantly increases the survival duration of implanted animals.

<b>CONCLUSIONb>AS-mCLB1 is likely to be useful in future cancer therapy, which may be associated with its ability to down-regulate the expression of CLB1 and then induce G1arrest and apoptosis in tumor cells.

Animals ; Apoptosis ; Cell Proliferation ; Cell Survival ; Cyclin B ; antagonists & inhibitors ; genetics ; Cyclin B1 ; DNA, Antisense ; pharmacology ; DNA, Complementary ; pharmacology ; G1 Phase ; Mice ; Mice, Inbred C57BL ; Neoplasm Transplantation ; Neoplasms, Experimental ; pathology ; therapy