OBJECTIVETo explore the role of F10 gene in regulating cell cycles of choriocarcinoma cells and the underlying mechanisms.

METHODSUsing untreated cells as the control, JAR cells with F10 gene silencing or stable F10 over-expression were examined for cell cycle changes by flow cytometry (FCM) and for expressions of cyclin and cyclin-dependent kinase (CDKs) with Western blotting and immunofluorescence technique.

RESULTSJAR cells over-expressing F10 gene showed reduced duration of cell cycle compared with untreated and with cells after F10 gene silencing. In F10-over-expressing cells, Western blotting revealed significantly up-regulated expressions of cyclin A2, B1, D1, E and CDK2, 6, and 7, but not CDK4, as compared with the control cells and cells with F10 gene silencing (P<0.05), and these results were consistent with those by immunofluorescence assay.

CONCLUSIONF10 gene may accelerate cell cycle progression and promote cell proliferation by up-regulating the expressions of cyclin A2, B1, D1, E and CDK 2, 4, 6, 7 in choriocarcinoma cells.

Cell Cycle ; Cell Division ; Cell Line, Tumor ; Cell Proliferation ; Choriocarcinoma ; metabolism ; Cyclin-Dependent Kinases ; metabolism ; Cyclins ; metabolism ; Factor X ; genetics ; Female ; Gene Silencing ; Humans ; Pregnancy

Meiotic recombination is carried out through a specialized pathway for the formation and repair of DNA double-strand breaks (DSBs) made by the Spo11 protein. The present study shed light on the functional role of cyclin, CYC2, in Tetrahymena thermophila which has transcriptionally high expression level during meiosis process. Knocking out the CYC2 gene results in arrest of meiotic conjugation process at 2.5-3.5 h after conjugation initiation, before the meiosis division starts, and in company with the absence of DSBs. To investigate the underlying mechanism of this phenomenon, a complete transcriptome profile was performed between wild-type strain and CYC2 knock-out strain. Functional analysis of RNA-Seq results identifies related differentially expressed genes (DEGs) including SPO11 and these DEGs are enriched in DNA repair/mismatch repair (MMR) terms in homologous recombination (HR), which indicates that CYC2 could play a crucial role in meiosis by regulating SPO11 and participating in HR.
Cell Cycle Checkpoints ; Cyclins ; genetics ; metabolism ; DNA Breaks, Double-Stranded ; DNA Mismatch Repair ; DNA Repair ; Endodeoxyribonucleases ; genetics ; metabolism ; Homologous Recombination ; Meiosis ; Microscopy, Fluorescence ; Phenotype ; Protozoan Proteins ; genetics ; metabolism ; Real-Time Polymerase Chain Reaction ; Sequence Analysis, RNA ; Tetrahymena thermophila ; genetics ; metabolism ; Transcriptome

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.
Animals ; Animals, Newborn ; Biomarkers ; metabolism ; Cell Proliferation ; genetics ; Cyclin-Dependent Kinase 2 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p57 ; genetics ; metabolism ; Cyclins ; genetics ; metabolism ; Gene Expression Regulation ; Hippocampus ; cytology ; metabolism ; Ki-67 Antigen ; genetics ; metabolism ; Magnetic Fields ; MicroRNAs ; genetics ; metabolism ; Neural Stem Cells ; cytology ; metabolism ; Primary Cell Culture ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

Although it has been suggested that kinesin family member 14 (KIF14) has oncogenic potential in various cancers, including hepatocellular carcinoma (HCC), the molecular mechanism of this potential remains unknown. We aimed to elucidate the role of KIF14 in hepatocarcinogenesis by knocking down KIF14 in HCC cells that overexpressed KIF14. After KIF14 knockdown, changes in tumor cell growth, cell cycle and cytokinesis were examined. We also examined cell cycle regulatory molecules and upstream Skp1/Cul1/F-box (SCF) complex molecules. Knockdown of KIF14 resulted in suppression of cell proliferation and failure of cytokinesis, whereas KIF14 overexpression increased cell proliferation. In KIF14-silenced cells, the levels of cyclins E1, D1 and B1 were profoundly decreased compared with control cells. Of the cyclin-dependent kinase inhibitors, the p27Kip1 protein level specifically increased after KIF14 knockdown. The increase in p27Kip1 was not due to elevation of its mRNA level, but was due to inhibition of the proteasome-dependent degradation pathway. To explore the pathway upstream of this event, we measured the levels of SCF complex molecules, including Skp1, Skp2, Cul1, Roc1 and Cks1. The levels of Skp2 and its cofactor Cks1 decreased in the KIF14 knockdown cells where p27Kip1 accumulated. Overexpression of Skp2 in the KIF14 knockdown cells attenuated the failure of cytokinesis. On the basis of these results, we postulate that KIF14 knockdown downregulates the expression of Skp2 and Cks1, which target p27Kip1 for degradation by the 26S proteasome, leading to accumulation of p27Kip1. The downregulation of Skp2 and Cks1 also resulted in cytokinesis failure, which may inhibit tumor growth. To the best of our knowledge, this is the first report that has identified the molecular target and oncogenic effect of KIF14 in HCC.
Carcinoma, Hepatocellular/*metabolism ; Cyclin-Dependent Kinase Inhibitor p27/genetics/*metabolism ; Cyclins/genetics/metabolism ; *Cytokinesis ; Gene Silencing ; Hep G2 Cells ; Humans ; Kinesin/genetics/*metabolism ; Liver Neoplasms/*metabolism ; Oncogene Proteins/genetics/*metabolism ; Proteasome Endopeptidase Complex/metabolism ; RNA, Messenger/genetics/metabolism ; S-Phase Kinase-Associated Proteins/genetics/metabolism ; *Ubiquitination

OBJECTIVETo investigate c-myc and CCNE2 gene amplifications and their relationship in breast cancer.

METHODSSixty-six infiltrating ductal breast carcinomas with foci of ductal carcinoma in situ components collected from January 2005 to December 2007 were selected for tissue microarray and quantitative multi-gene FISH for c-myc and CCNE2 gene amplification, and the relationship with the clinicopathologic features was analyzed.

RESULTSOf the 66 cases, 18 (27.3%) showed c-myc amplification and 23 (34.8%) showed CCNE2 amplification. A strong correlation was found between c-myc and CCNE2 amplification (P < 0.01). The breast cancers showing c-myc and CCNE2 amplifications were all aneuploidy, and were HER2 positive (P < 0.05). Tumors with c-myc amplification also showed higher Ki-67 index (P < 0.05).

CONCLUSIONSC-myc and CCNE2 amplifications are common events in breast cancer, and they often coexist. C-myc and CCNE2 genes may play critical roles in the pathogenesis and development of breast cancer through unique and overlapping signaling pathways.

Aneuploidy ; Breast Neoplasms ; genetics ; Carcinoma in Situ ; genetics ; Carcinoma, Ductal, Breast ; genetics ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; Cyclins ; genetics ; Female ; Gene Amplification ; Genes, myc ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Tissue Array Analysis

To study the effect of micro (mi)RNA on cellular proliferation induced by hepatitis B x protein, HBx, in human liver cells and to investigate the underlying molecular mechanism of this cancer-related effect. The human L02 hepatocyte cell line was stably transfected with HBx (L02/HBx) or an HBx mutant (L02/HBx-d382) that induces higher levels of cellular proliferation. The differential miRNA expression profiles were determined by microarray analysis and confirmed by real-time PCR. Two miRNAs, miR-338-3p and miR-551b, that were found to be significantly down-regulated in the L02/HBx-d382 cells were selected for further study and transfected individually into cells using the lipofectamine procedure. The cell survival rate was analyzed by MTT assay, and cell cycles were assessed by flow cytometry. Expressions of cyclinD1, cyclinG1, and E2F1 were assessed by real-time PCR and Western blotting. Compared with the microarray miRNA profile of L02/pcDNA3.0 cells, six miRNAs were up-regulated and five miRNAs were down-regulated in the L02/HBx-d382 cells, while four miRNAs were up-regulated and 12 were down-regulated in the L02/HBx cells. The microarray results were consistent with real-time PCR results. Transfection of miR-338-3p and miR-551b significantly inhibited the cell survival rates (P less than 0.001) and induced G0/G1 phase cycle arrest. According to MTT results: for L02/HBx-d382 cells, compared with lipofectamine or non-transfected (NC) controls, the t value of miR-338-3p was 10.402, 9.133 and the t value of miR-551b was 8.763, 7.403; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 9.105, 8.074 and the t value of miR-551b was 7.673, 7.52. According to flow cytometry results: for L02/HBx-d382 cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 12.173, 11.107 and the t value of miR-551b was 15.364, 13.377; for L02/HBx cells, compared with lipofectamine or NC controls, the t value of miR-338-3p was 15.416, 13.378, and the t value of miR-551b was 13.276, 13.109. The protein levels of cyclinD1, cyclinG1, and E2F1 were significantly reduced by both miR-338-3p and miR-551b ( P less than 0.001). For L02/HBx-d382 cells, compared with lipofectamine or NC controls: E2F1 had t = 11.132, 10.031 and 12.017, 10.973, respectively; cyclinD1 had t = 15.654, 15.013 and 15.447, 14.733, respectively; cyclinG1 had t = 8.017, 7.661 and 7.402, 7.417, respectively. For L02/HBx cells, compared with lipofectamine or NC controls: E2F1 had t = 14.244, 13.331 and 15.022, 14.468, respectively; cyclinD1 had t = 8.695, 8.137 and 7.877, 7.503, respectively; cyclinG1 had t = 7.73, 7.471 and 7.596, 7.41, respectively. In contrast, the mRNA levels for E2F1, cyclinD1, and cylcinG1 showed no significant differences between the miRNA transfected cells and controls. Wild-type HBx and the high proliferation-inducing mutant HBx can influence the miRNA expression profile of L02 cells. HBx down-regulates miR-338-3p and miR-551b in L02 cells, and the high proliferation-inducing mutant has a more robust effect. The mechanism of miR-338-3p- or miR-551b-mediated cell growth inhibition appears to be related to the direct modulation of cyclinD1, cyclinG1, and E2F1.
Blotting, Western ; Carcinoma, Hepatocellular ; genetics ; metabolism ; pathology ; Cell Cycle ; Cell Line ; Cell Proliferation ; Cyclins ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Genes, Viral ; Hepatitis B virus ; genetics ; metabolism ; Hepatocytes ; metabolism ; pathology ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; MicroRNAs ; genetics ; metabolism ; Mutation ; Oligonucleotide Array Sequence Analysis ; RNA, Messenger ; genetics ; Real-Time Polymerase Chain Reaction ; Trans-Activators ; genetics ; metabolism ; Transfection

Human embryonic stem cells (hESCs) are considered to be able to stably maintain their characteristics in vitro for prolonged periods, but we had previously encountered changes in proliferative ability and differentiation potential during extended culture of hESCs. Therefore, we investigated the proliferative ability and differentiation potential of hESCs during long-term culture. The hESCs, SNUhES3, were used to analyze population-doubling time, proliferation rate and differentiation potential. We classified hESCs into three groups according to culture period. Ten colonies of hESCs for each group were daily measured colony area and population-doubling time was assessed by the changes of colony area. Proliferation rate of hESCs was measured by 5-bromo-2'-deoxyuridine (BrdU) assay and telomerase activity. To evaluate differentiation potentials for hESCs, expression levels of undifferentiated and/or differentiated hESCs markers were examined by FACS, RT-PCR and immunostaining. Population-doubling time of early passage hESCs was longer than those of middle or late passage. Proliferative ability of hESCs was accelerated depending on culture periods. Cellular morphologies and the expression level of each three germ layer markers were obviously different from each passage of reattached embryoid bodies (EBs) after spontaneous differentiation. Differentiated cells of late passage expressed higher levels of undifferentiated markers such as Oct4 and SSEA4 than those of early and middle passage. But differentiated cells of early and middle passage expressed higher level of differentiated state markers, Nestin (ectoderm), Brachyury (mesoderm), HNF3beta (endoderm). From these results, it can be inferred that hESCs show higher proliferative abilities and reduced differentiation potentials as the passage number increased. Therefore, we conclude that early passage hESCs could be more suitable than middle and late passage hESCs in differentiation studies.
Biological Markers/metabolism ; Bromodeoxyuridine/metabolism ; *Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Cyclins/metabolism ; DNA-Binding Proteins/genetics/metabolism ; Embryonic Stem Cells/*cytology/enzymology ; Flow Cytometry ; Gene Expression Regulation ; Homeodomain Proteins/genetics/metabolism ; Humans ; Karyotyping ; Octamer Transcription Factor-3/genetics/metabolism ; Telomerase/metabolism ; Time Factors

OBJECTIVETo explore the relationship between human cyclin C (CCNC) gene and childhood acute lymphocytic leukemia (ALL).

METHODSThe total RNA isolated from myeloid tissues of normal children and of children with newly diagnosed ALL and from ALL cell line 6T-CEM was reversely transcribed into cDNA. Real-time fluorescence quantitative PCR method was used to detect CCNC gene expression.

RESULTSCCNC was expressed in myeloid tissues of normal children and of children with newly diagnosed ALL as well as 6T-CEM. The relative expression level of CCNC gene in children with newly diagnosed ALL was significantly lower than in normal controls (2.35 +/- 0.83 vs 13.5 +/- 0.30; P <0.05).

CONCLUSIONSCCNC gene shows lower expression in children with newly diagnosed ALL, suggesting that it may be a tumor suppressing gene in childhood ALL.

Child ; Cyclin C ; Cyclins ; genetics ; Female ; Fluorescence ; Humans ; Male ; Polymerase Chain Reaction ; methods ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; metabolism

BACKGROUNDUncontrolled cell division is one of the hallmarks of tumor growth. Researches have been focused on numerous molecules involved in this process. Cyclins are critical regulatory proteins of cell cycle progression and/or transcription. The present study aimed to investigate the anti-proliferative effect of cyclin L2, and to define its growth regulatory mechanisms using human lung adenocarcinoma cell line A549.

METHODSHuman cyclin L2 was transfected into human lung adenocarcinoma cells (A549 cell), and was expressed in a mammalian expression vector pcDNA3.1. The effects and mechanisms of the cyclin L2 in cell growth, cell cycle analysis and apoptosis were studied by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), flow cytometry or Western blot, respectively.

RESULTSOverexpression of cyclin L2 inhibited the growth of A549 cells. Cell cycle analysis in cells transfected with pCCNL2 revealed an increment in proportion in G0/G1 phase ((68.07 +/- 4.2)%) in contrast to (60.39 +/- 2.82)% of the cells transfected with mock vector. Apoptosis occurred in (7.25 +/- 0.98)% cells transfected with pCCNL2, as compared with (1.25 +/- 0.21)% of the mock vector control group. Cyclin L2-induced-G0/G1 arrest and apoptosis involved upregulation of caspase-3 and downregulation of Bcl-2 and survivin.

CONCLUSIONThe results indicate that overexpression of cyclin L2 protein may promote efficient growth inhibition of human lung adenocarcinoma cells by inducing G0/G1 cell cycle arrest and apoptosis.

Apoptosis ; Caspase 3 ; biosynthesis ; Cell Cycle ; Cell Line, Tumor ; Cyclins ; genetics ; physiology ; Humans ; Lung Neoplasms ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; antagonists & inhibitors ; Transcription Factors ; genetics ; physiology ; Transfection

OBJECTIVETo observe the effect of human cytomegalovirus infection on the host cellular DNA synthesis and expression of cyclones.

METHODSHCMV infected cell was established in vitro by incubating passage cultured HEL and HCMV AD169 strain with different titres. The cells were synchronized in the G0/G1 stage by contact inhibition and infected with strain AD169 of HCMV at an MOI of 5 PFU per cell. We harvested infected cell at different time 0 h, 3 h, 6 h, 24 h, 72 h and 96 h post infection. Then the cell cycle progress was measured. Meanwhile, the DNA content and expression of proteins of cycline E, cycline A and cycline D1 were determined with FCM and Western Blot respectively.

RESULTSWe found that the amount of S stage cell infected by HCMV had increased dramatically, and that of G2/M stage cell reduced during 24 h-96 h PI, and no G2/M stage cell was detected within 96 h PI. The content of 2N DNA maintained unchangeable for 24 h after infection and the content of total DNA in infected cells began to increase within 48 h PI, and the substantial cell with 2N DNA were observed 72 h after infection. However, DNA content was not altered in control group of normal HEL and HCMV PAA group. CyclinE protein was induced 12 h PI and peak induction occurred 24 h PI in contact-inhibited cells. CyclinA protein expression was not induced in HCMV infected density-arrested cells. The abundance of cyclinD1 decreased 24 h PI.

CONCLUSIONThe expression of cyclinE and activity of cyclinE/Cdk2 kinase are increased obviously in G0/G1 stage cells infected with HCMV, which may induce the cell cycle to overpass G1/S restriction point and make the cell cycle arrested in later G1 stage. HCMV can not activate cellular DNA synthesis, and increase of total DNA content in infected cells result from the viral DNA replication.

Cell Cycle ; Cells, Cultured ; Cyclins ; genetics ; metabolism ; Cytomegalovirus ; physiology ; Cytomegalovirus Infections ; genetics ; metabolism ; Gene Expression ; Humans