Search results for "Cyclin B"
showing 10 items of 20 documents
G2/M checkpoint regulation and apoptosis facilitate the nuclear egress of parvoviral capsids
2022
The nuclear export factor CRM1-mediated pathway is known to be important for the nuclear egress of progeny parvovirus capsids in the host cells with virus-mediated cell cycle arrest at G2/M. However, it is still unclear whether this is the only pathway by which capsids exit the nucleus. Our studies show that the nuclear egress of DNA-containing full canine parvovirus. capsids was reduced but not fully inhibited when CRM1-mediated nuclear export was prevented by leptomycin B. This suggests that canine parvovirus capsids might use additional routes for nuclear escape. This hypothesis was further supported by our findings that nuclear envelope (NE) permeability was increased at the late stages…
Sequence of lethal events in HeLa cells exposed to the G2 blocking cytolethal distending toxin
2000
The bacterial cytolethal distending toxin (CDT) was previously shown to block the cell cycle of several cell lines at stage G2 through inactivation of the cyclin-dependent kinase Cdkl and without induction of DNA strand breaks. In the present study, we have analyzed, using various methods of analytical cytometry, the progressive transformation and delayed lethal events in the tumor-derived HeLa cell line temporarily exposed to CDT. The cell proliferation arrest induced by CDT was irreversible but, starting about two days after exposure, the G2 block released partially, concomitantly with a decline in the level of Cdkl phosphorylation. This partial release resulted in endoreduplication, lead…
Cyclin B1 overexpression in conventional oral squamous cell carcinoma and verrucous carcinoma- A correlation with clinicopathological features.
2012
Background: Nuclear localization of cyclin B1 is an indicator for cells undergoing mitotic division, and the overexpression has shown promising results as a good prognostic predictor for patients of squamous cell carcinoma (SCC). Cyclin B1 overexpression among histological grades of conventional oral squamous cell carcinoma (COSCC), as well as comparison with verrucous carcinoma (VC) has been less investigated. Study Design: Immunohistochemical expression of cyclin B1 was compared with various clinicopathological features in 30 primary COSCC and 31 primary VC cases. Result: Cyclin B1 showed significant overexpression for some clinical features for both the variants of oral squamous cell car…
Liver-specific p38α deficiency causes reduced cell growth and cytokinesis failure during chronic biliary cirrhosis in mice
2012
p38α mitogen-activated protein kinases (MAPK) may be essential in the up-regulation of proinflammatory cytokines and can be activated by transforming growth factor β, tumor necrosis factor-α, interleukin-1β, and oxidative stress. p38 MAPK activation results in hepatocyte growth arrest, whereas increased proliferation has been considered a hallmark of p38α-deficient cells. Our aim was to assess the role of p38α in the progression of biliary cirrhosis induced by chronic cholestasis as an experimental model of chronic inflammation associated with hepatocyte proliferation, apoptosis, oxidative stress, and fibrogenesis. Cholestasis was induced in wildtype and liver-specific p38α knockout mice by…
N-(INDAZOLYL)BENZAMIDO DERIVATIVES AS CDK1 INHIBITORS: DESIGN, SYNTHESIS, BIOLOGICAL ACTIVITY, AND MOLECULAR DOCKING STUDIES
2009
A series of N-1H-indazole-1-carboxamides has been synthesized and their effects on both CDK1/cyclin B and the K-562 (human chronic myelogenus leukemia) cell line were evaluated. Using a computational model, we have observed that all the most active compounds 9e, f, i-n exhibited the same binding mode of purvanalol A in the ATP-binding cleft. Although they were able to moderately inhibit the leukemic cell line K-562 and to show inhibitory activity against the Cdc2-Cyclin B kinase in the low micromolar range, they turned out to be non-cytotoxic against HuDe (IZSL) primary cell cultures from human derm. These preliminary results are quite encouraging in view of the low toxicity demonstrated by…
Integrative analysis of cyclin protein levels identifies cyclin b1 as a classifier and predictor of outcomes in breast cancer
2009
Abstract Purpose: We studied the expression levels of cyclins B1, D1, and E1 and the implications of cyclin overexpression for patient outcomes in distinct breast cancer subtypes defined by clinical variables and transcriptional profiling. Experimental Design: The expression levels of cyclins B1, D1, and E1 were quantified in 779 breast tumors and 53 cell lines using reverse phase protein arrays and/or transcriptional profiling. Results: Whereas cyclin E1 overexpression was a specific marker of triple-negative and basal-like tumors, cyclin B1 overexpression occurred in poor prognosis hormone receptor–positive, luminal B and basal-like breast cancers. Cyclin D1 overexpression occurred in lum…
Rot1 plays an antagonistic role to Clb2 in actin cytoskeleton dynamics throughout the cell cycle.
2007
ROT1 is an essential gene whose inactivation causes defects in cell cycle progression and morphogenesis in budding yeast. Rot1 affects the actin cytoskeleton during the cell cycle at two levels. First, it is required for the maintenance of apical growth during bud growth. Second, Rot1 is necessary to polarize actin cytoskeleton to the neck region at the end of mitosis; because of this defect, rot1 cells do not properly form a septum to complete cell division. The inability to polarize the actin cytoskeleton at the end of mitosis is not due to a defect in the recruitment of the polarisome scaffold protein Spa2 or the actin cytoskeleton regulators Cdc42 and Cdc24 in the neck region. Previous …
Functional Connection Between the Clb5 Cyclin, the Protein Kinase C Pathway and the Swi4 Transcription Factor in Saccharomyces cerevisiae
2005
Abstract The rsf12 mutation was isolated in a synthetic lethal screen for genes functionally interacting with Swi4. RSF12 is CLB5. The clb5 swi4 mutant cells arrest at G2/M due to the activation of the DNA-damage checkpoint. Defects in DNA integrity was confirmed by the increased rates of chromosome loss and mitotic recombination. Other results suggest the presence of additional defects related to morphogenesis. Interestingly, genes of the PKC pathway rescue the growth defect of clb5 swi4, and pkc1 and slt2 mutations are synthetic lethal with clb5, pointing to a connection between Clb5, the PKC pathway, and Swi4. Different observations suggest that like Clb5, the PKC pathway and Swi4 are in…
Localization of HSP70, Cdc2, and cyclin B in sea urchin oocytes in non-stressed conditions.
2003
In Paracentrotus lividus embryos, a Mediterranean sea urchin species, HSP70 is present in all the cells. During cell division it localizes under normal growth conditions on the centrosomes and on the whole isolated mitotic apparatus. Now, in situ hybridization, Western blot analyses, and immunohistochemistry show that the HSP70 mRNA is present in both small and large P. lividus oocytes, that all four isoforms of HSP70 can be found also in the oocytes, and that a certain amount of HSP70 localizes on asters and spindles during polar body formation. Moreover, two representative cell-cycle related proteins, cyclin B, and Cdc2, are present both in small and large oocytes, concentrating in the ge…
Raloxifene increases proliferation of human endothelial cells in association with increased gene expression of cyclins A and B1.
2006
Objective To examine the proliferative effect of of raloxifene on human umbilical-vein endothelial cells (HUVECs), and to investigate whether there is an associated increased expression of some key regulators of the cell cycle. Design Cell culture for different incubation times. Setting University research laboratory. Patient(s) Sources of HUVECs. Intervention(s) Measurement of cell proliferation, of protein levels of cyclin A, cyclin B1, cyclin D1, cyclin-dependent protein kinase (CDK) 2, CDK4, and p27 Kip1 , and of messenger RNA expression of cyclin A, cyclin B1, and p27 Kip1 . Main Outcome Measure(s) Cell proliferation was measured by the 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyltetrazol…