The Cdk inhibitors p25rum1 and p40SIC1 are functional homologues that play similar roles in the regulation of the cell cycle in fission and budding yeast

1998 ◽  
Vol 111 (6) ◽  
pp. 843-851 ◽  
Author(s):  
A. Sanchez-Diaz ◽  
I. Gonzalez ◽  
M. Arellano ◽  
S. Moreno
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
G1 Phase ◽  
G1 Arrest ◽  
Cdk Inhibitors ◽  
A Cell ◽  
High Level ◽  
Cell Cycle Block ◽  
Cdc28 Kinase ◽  
P34 Cdc2

p25rum1 and p40SIC1 are specific inhibitors of p34(cdc2/CDC28) kinase complexes with B-type cyclins that play a central role in the regulation of the G1 phase of the cell cycle. We show here that low levels of expression of SIC1 in Schizosaccharomyces pombe rescues all the phenotypes of cells lacking the rum1+ gene. In addition, high level expression of SIC1 in S. pombe induces extra rounds of DNA replication without mitosis, a phenotype very similar to the overexpression of rum1+. Transient expression of rum1+ in S. cerevisiae restores the G1 arrest phenotype of cdc4 sic1Delta double mutants. Overproduction of rum1+ in Saccharomyces cerevisiae causes a cell cycle block in G1 with a phenotype similar to inactivation of all the Clb cyclins. Finally, we have mapped the cyclin interacting domain and Cdk inhibitory domain to a region of about 80 amino acids in p25rum1 that has significant homology to the C-terminal domain of p40SIC1. All these observations suggest that fission yeast p25rum1 and budding yeast p40SIC1 define a family of Cdk inhibitors that specifically down regulate cyclin B/Cdk1 during the G1 phase of the cell cycle.

scholarly journals The p21WAF1/CIP1 Promoter Is Methylated in Rat-1 Cells: Stable Restoration of p53-Dependent p21WAF1/CIP1 Expression after Transfection of a Genomic Clone Containing the p21WAF1/CIP1 Gene

2000 ◽  
Vol 20 (4) ◽  
pp. 1291-1298 ◽  
Author(s):  
Lindsey A. Allan ◽  
Trevor Duhig ◽  
Moira Read ◽  
Mike Fried
Keyword(s):  
Cell Cycle ◽  
Promoter Region ◽  
P53 Protein ◽  
Artificial Chromosome ◽  
Uv Treatment ◽  
X Ray ◽  
Cpg Dinucleotides ◽  
A Cell ◽  
Cell Cycle Block ◽  
Inducible Gene

ABSTRACT Rat-1 cells are used in many studies on transformation, cell cycle, and apoptosis. Whereas UV treatment of Rat-1 cells results in apoptosis, X-ray treatment does not induce either apoptosis or a cell cycle block. X-ray treatment of Rat-1 cells results in both an increase of p53 protein and expression of the p53-inducible geneMDM2 but not the protein or mRNA of the p53-inducible p21WAF1/CIP1 gene, which in other cells plays an important role in p53-mediated cell cycle block. The lack of p21WAF1/CIP1 expression appears to be the result of hypermethylation of the p21WAF1/CIP1 promoter region, as p21WAF1/CIP1 protein expression could be induced by growth of Rat-1 cells in the presence of 5-aza-2-deoxycytidine. Furthermore, sequence analysis of bisulfite-treated DNA demonstrated extensive methylation of cytosine residues in CpG dinucleotides in a CpG-rich island in the promoter region of the p21WAF1/CIP1 gene. Stable X-ray-induced p53-dependent p21WAF1/CIP1 expression and cell cycle block were restored to a Rat-1 clone after transfection with a P1 artificial chromosome (PAC) DNA clone containing a rat genomic copy of the p21WAF1/CIP1 gene. The absence of expression of the p21WAF1/CIP1 gene may contribute to the suitability of Rat-1 cells for transformation, cell cycle, and apoptosis studies.

Three proteins required for early steps in the protein secretory pathway also affect nuclear envelope structure and cell cycle progression in fission yeast

2002 ◽  
Vol 115 (2) ◽  
pp. 421-431
Author(s):  
Anna Matynia ◽  
Sandra S. Salus ◽  
Shelley Sazer
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Fission Yeast ◽  
Cell Cycle Progression ◽  
Secretory Pathway ◽  
Yeast Cells ◽  
Ran Gtpase ◽  
A Cell ◽  
Cell Cycle Block ◽  
Er Membrane

The Ran GTPase is an essential protein that has multiple functions in eukaryotic cells. Fission yeast cells in which Ran is misregulated arrest after mitosis with condensed, unreplicated chromosomes and abnormal nuclear envelopes. The fission yeast sns mutants arrest with a similar cell cycle block and interact genetically with the Ran system. sns-A10, sns-B2 and sns-B9 have mutations in the fission yeast homologues of S. cerevisiae Sar1p, Sec31p and Sec53p, respectively, which are required for the early steps of the protein secretory pathway. The three sns mutants accumulate a normally secreted protein in the endoplasmic reticulum (ER), have an increased amount of ER membrane, and the ER/nuclear envelope lumen is dilated. Neither a post-ER block in the secretory pathway, nor ER proliferation caused by overexpression of an integral ER membrane protein, results in a cell cycle-specific defect. Therefore, the arrest seen in sns-A10, sns-B2 and sns-B9 is most likely due to nuclear envelope defects that render the cells unable to re-establish the interphase organization of the nucleus after mitosis. As a consequence, these mutants are unable to decondense their chromosomes or to initiate of the next round of DNA replication.

scholarly journals Synergistic Impact of Xanthorrhizol and d-δ-tocotrienol on the Proliferation of Murine B16 Melanoma Cells and Human DU145 Prostate Carcinoma Cells (P06-042-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Maureen Beebe ◽  
Rami Najjar ◽  
Darren Chan ◽  
Chappell Madhani ◽  
Manal Elfakhani ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Synergistic Effect ◽  
Tumor Cells ◽  
Prostate Carcinoma ◽  
B16 Melanoma ◽  
Carcinoma Cells ◽  
G1 Phase ◽  
G1 Arrest ◽  
Funding Sources ◽  
Georgia State University

Abstract Objectives Xanthorrhizol, a sesquiterpene, and d-δ-tocotrienol, a vitamin E molecule, each suppresses the proliferation of a number of tumor cells. This study aims to examine the potentially synergistic effect of xanthorrhizol and d-δ-tocotrienol in tumor cells. Methods Murine B16 melanoma and human DU145 prostate carcinoma cells were incubated for 48 h (B16) or 72 h (DU145) with xanthorrhizol or d-δ-tocotrienol before cell populations were determined by CellTiter 96â Aqueous One Solution. Cells incubated with the agents for 24 hours were stained with propidium iodide and analyzed for cell cycle using flow cytometry and MultiCycle AV. Isobologram and combination index (CI) were used to demonstrate their synergistic anti-proliferative impacts. Results Xanthorrhizol (0–200 µmol/L) and d-δ-tocotrienol (0–40 µmol/L) each elicited a concentration-dependent suppression of the proliferation of B16 cells. A blend of 16.25 µmol/L xanthorrhizol and 10 µmol/L d-δ-tocotrienol achieved 69% (P < 0.05) growth suppression of B16 cells, exceeding the sum of individual effects. B16 cells incubated with 5 and 10 µmol/L d-δ-tocotrienol for 24-h had a concentration-dependent increase in the percentage of cells in the G1 phase with a concomitant decrease in the percentage of cells in the S phase. The G1/S ratio, an indicator of cell cycle arrest at the G1 phase, increased from 1.73 ± 0.05 (Control) to 2.01 ± 0.10 (5 µmol/L) and 2.73 ± 0.05 (10 µmol/L). A parallel pattern of concentration-dependent increase in the G1/S ratio was induced by xanthorrhizol at concentrations equivalent to 25% (16.25 µmol/L) and 50% (32.5 µmol/L) of its IC50 value. A blend of 5 µmol/L d-δ-tocotrienol and 16.25 µmol/L xanthorrhizol, each at no-effect concentrations, significantly increased the percentage of B16 cells in the G1 phase to 62.6 ± 0.6%. Isobologram and CI confirmed the synergistic effect of xanthorrhizol (50 and 100 μmol/L) and d-δ-tocotrienol (10 and 20 μmol/L) on the proliferation of DU145 cells. Conclusions Xanthorrhizol and d-δ-tocotrienol synergistically suppress tumor cell proliferation by inducing G1 arrest and may have potential in cancer prevention and therapy. Funding Sources American River Nutrition, Inc. and the University Assistantship Program and the Department of Nutrition of Georgia State University.

scholarly journals Differential Taxol-dependent arrest of transformed and nontransformed cells in the G1 phase of the cell cycle, and specific-related mortality of transformed cells.

1996 ◽  
Vol 135 (3) ◽  
pp. 689-700 ◽  
Author(s):  
M O Trielli ◽  
P R Andreassen ◽  
F B Lacroix ◽  
R L Margolis
Keyword(s):  
Cell Cycle ◽  
T Antigen ◽  
Transformed Cells ◽  
G1 Phase ◽  
G1 Arrest ◽  
Fibroblast Cells ◽  
Related Mortality

Taxol (paclitaxel) induces a microtubule hyperassembled state, and effectively blocks cells in mitosis. Here we report that Taxol also induces a stable late-G1 block in nontransformed REF-52 and WI-38 mammalian fibroblast cells, but not in T antigen-transformed cells of the same parental lineage. G1 arrest is characterized by partially dephosphorylated pRb, and inactive cdk2 kinase. Nontransformed cells recover normally from Taxol arrest. In contrast, T antigen transformed cells continue inappropriately past both G1 and G2-M in the presence of Taxol, and undergo a rapid death upon release. These results demonstrate a microtubule sensitive step in G1 regulation of nontransformed fibroblast cells. Also, Taxol selectively induces death of transformed cells, possibly because they slip the Taxol-dependent G1 arrest, as well as G2/M arrest, which are both specific to nontransformed cells.

scholarly journals Induction of G1 arrest by down-regulation of cyclin D3 in T cell hybridomas.

1995 ◽  
Vol 182 (2) ◽  
pp. 401-408 ◽  
Author(s):  
S Miyatake ◽  
H Nakano ◽  
S Y Park ◽  
T Yamazaki ◽  
K Takase ◽  
...  
Keyword(s):  
Cell Cycle ◽  
T Cell ◽  
T Cell Receptor ◽  
Kinase Activity ◽  
Growth Arrest ◽  
Cell Receptor ◽  
Cyclin D3 ◽  
G1 Phase ◽  
G1 Arrest ◽  
Down Regulation

The relationship between activation-induced growth inhibition and regulation of the cell cycle progression was investigated in T cell hybridomas by studying the function of the cell cycle-regulating genes such as G1 cyclins and their associated kinases. Activation of T cell hybridomas by anti-T cell receptor antibody induces growth arrest at G1 phase of the cell cycle and subsequently results in activation-driven cell death. Rapid reduction of both messenger RNA and protein level of the cyclin D3 is accompanied by growth arrest upon activation. Although the residual cyclin D3 protein forms a complex with cdk4 protein, cyclin D3-dependent kinase activity is severely impaired. Stable transfectants engineered to express cyclin D3 override the growth arrest upon activation. These results imply that the activation signal through T cell receptor induces the down-regulation of cyclin D3 expression and cyclin D3-dependent kinase activity, leading to growth arrest in G1 phase of the cell cycle in T cells.

scholarly journals The duration of mitosis and daughter cell size are modulated by nutrients in budding yeast

2017 ◽  
Vol 216 (11) ◽  
pp. 3463-3470 ◽  
Author(s):  
Ricardo M. Leitao ◽  
Douglas R. Kellogg
Keyword(s):  
Cell Cycle ◽  
Cell Size ◽  
Daughter Cell ◽  
Slow Growth ◽  
Budding Yeast ◽  
Size Control ◽  
G1 Phase ◽  
Large Reduction ◽  
Duration Of Mitosis ◽  
Cell Cycle Entry

The size of nearly all cells is modulated by nutrients. Thus, cells growing in poor nutrients can be nearly half the size of cells in rich nutrients. In budding yeast, cell size is thought to be controlled almost entirely by a mechanism that delays cell cycle entry until sufficient growth has occurred in G1 phase. Here, we show that most growth of a new daughter cell occurs in mitosis. When the rate of growth is slowed by poor nutrients, the duration of mitosis is increased, which suggests that cells compensate for slow growth in mitosis by increasing the duration of growth. The amount of growth required to complete mitosis is reduced in poor nutrients, leading to a large reduction in cell size. Together, these observations suggest that mechanisms that control the extent of growth in mitosis play a major role in cell size control in budding yeast.

scholarly journals Dissection of the genetic programs of p53-mediated G1 growth arrest and apoptosis: blocking p53-induced apoptosis unmasks G1 arrest

Blood ◽  
1995 ◽  
Vol 85 (10) ◽  
pp. 2691-2698 ◽  
Author(s):  
C Guillouf ◽  
X Grana ◽  
M Selvakumaran ◽  
A De Luca ◽  
A Giordano ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Target Genes ◽  
Ectopic Expression ◽  
Growth Arrest ◽  
Genetically Engineered ◽  
Temperature Sensitive ◽  
G1 Arrest ◽  
Induced Apoptosis ◽  
High Level ◽  
And Function

Employing the myeloblastic leukemia M1 cell line, which does not express endogenous p53, and genetically engineered variants, it was recently shown that activation of p53, using a p53 temperature-sensitive mutant transgene (p53ts), resulted in rapid apoptosis that was delayed by high level ectopic expression of bcl-2. In this report, advantage has been taken of these M1 variants to investigate the relationship between p53-mediated G1 arrest and apoptosis. Flow cytometric cell cycle analysis has provided evidence that activation of wild-type (wt) p53 function in M1 cells resulted in the induction of G1 growth arrest; this was clearly seen in the M1p53/bcl-2 cells because of the delay in apoptosis that unmasked p53-induced G1 growth arrest. This finding was further corroborated at the molecular level by analysis of the expression and function of key cell cycle regulatory genes in M1p53 versus M1p53/bcl-2 cells after the activation of wt p53 function; events that take place at early times during the p53-induced G1 arrest occur in both the M1p53 and the M1p53/bcl-2 cells, whereas later events occur only in the M1p53/bcl-2 cells, which undergo delayed apoptosis, thereby allowing the cells to complete G1 arrest. Finally, it was observed that a spectrum of p53 target genes implicated in p53-induced growth suppression and apoptosis were similarly regulated, either induced (gadd45, waf1, mdm2, and bax) or suppressed (c-myc and bcl-2), after activation of wt p53 function in M1p53 and M1p53/bcl-2 cells. Taken together, these findings show that wt p53 can simultaneously induce the genetic programs of both G1 growth arrest and apoptosis within the same cell type, in which the genetic program of cell death can proceed in either G1-arrested (M1p53/bcl-2) or cycling (M1p53) cells. These findings increase our understanding of the functions of p53 as a tumor suppressor and how alterations in these functions could contribute to malignancy.

scholarly journals The (+)-Brevipolide H Displays Anticancer Activity against Human Castration-Resistant Prostate Cancer: The Role of Oxidative Stress and Akt/mTOR/p70S6K-Dependent Pathways in G1 Checkpoint Arrest and Apoptosis

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2929
Author(s):  
Yi-Hua Sheng ◽  
Wohn-Jenn Leu ◽  
Ching-Nung Chen ◽  
Jui-Ling Hsu ◽  
Ying-Tung Liu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Mitochondrial Dysfunction ◽  
Anticancer Activity ◽  
Intracellular Signaling ◽  
G1 Phase ◽  
G1 Arrest ◽  
Ros Production ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant

Because conventional chemotherapy is not sufficiently effective against prostate cancer, various examinations have been performed to identify anticancer activity of naturally occurring components and their mechanisms of action. The (+)-brevipolide H, an α-pyrone-based natural compound, induced potent and long-term anticancer effects in human castration-resistant prostate cancer (CRPC) PC-3 cells. Flow cytofluorometric analysis with propidium iodide staining showed (+)-brevipolide H-induced G1 arrest of cell cycle and subsequent apoptosis through induction of caspase cascades. Since Akt/mTOR pathway has been well substantiated in participating in cell cycle progression in G1 phase, its signaling and downstream regulators were examined. Consequently, (+)-brevipolide H inhibited the signaling pathway of Akt/mTOR/p70S6K. The c-Myc inhibition and downregulation of G1 phase cyclins were also attributed to (+)-brevipolide H action. Overexpression of myristoylated Akt significantly rescued mTOR/p70S6K and downstream signaling under (+)-brevipolide H treatment. ROS and Ca2+, two key mediators in regulating intracellular signaling, were determined, showing that (+)-brevipolide H interactively induced ROS production and an increase of intracellular Ca2+ levels. The (+)-Brevipolide H also induced the downregulation of anti-apoptotic Bcl-2 family proteins (Bcl-2 and Bcl-xL) and loss of mitochondrial membrane potential, indicating the contribution of mitochondrial dysfunction to apoptosis. In conclusion, the data suggest that (+)-brevipolide H displays anticancer activity through crosstalk between ROS production and intracellular Ca2+ mobilization. In addition, suppression of Akt/mTOR/p70S6K pathway associated with downregulation of G1 phase cyclins contributes to (+)-brevipolide H-mediated anticancer activity, which ultimately causes mitochondrial dysfunction and cell apoptosis. The data also support the biological significance and, possibly, clinically important development of natural product-based anticancer approaches.

scholarly journals Antigen receptor-induced cell cycle arrest in WEHI-231 B lymphoma cells depends on the duration of signaling before the G1 phase restriction point.

1990 ◽  
Vol 10 (6) ◽  
pp. 3003-3012 ◽  
Author(s):  
D M Page ◽  
A L DeFranco
Keyword(s):  
Cell Cycle ◽  
Second Messengers ◽  
Antigen Receptor ◽  
G1 Phase ◽  
G1 Arrest ◽  
Receptor Stimulation ◽  
Kinase C ◽  
B Lymphoma Cells ◽  
Wehi 231 ◽  
Pharmacologic Agents

Stimulation of antigen receptors on WEHI-231 B lymphoma cells with anti-receptor antibodies (anti-immunoglobulin M [IgM]) causes irreversible growth arrest. This may be a model for antigen-induced tolerance to self components in the immune system. Antigen receptor stimulation also causes inositol phospholipid hydrolysis, producing diacylglycerol, which activates protein kinase C, and inositol 1,4,5-trisphosphate, which causes release of calcium from intracellular stores. To better understand the nature of the antigen receptor-induced growth arrest of WEHI-231 cells, we have examined the basis for it. WEHI-231 cells in various phases of the cell cycle were isolated by centrifugal elutriation, and their response was evaluated following treatment with either anti-IgM or pharmacologic agents that raise intracellular free calcium levels and activate protein kinase C. Treatment with anti-IgM or the pharmacologic agents did not lengthen the cell cycle. Instead, growth inhibition was solely the result of arrest in the G1 phase. The efficiency of G1 arrest increased with the length of time during which the cells received signaling before reaching the G1 phase arrest point. Maximum efficiency of arrest was achieved after approximately one cell cycle of receptor signaling. These results imply that anti-IgM causes G1 arrest of WEHI-231 cells by slowly affecting components required for S phase progression, rather than by rapidly inhibiting such components or by rapidly activating a suicide mechanism. Antigen receptor stimulation was twice as effective as stimulation via the mimicking reagents phorbol dibutyrate and ionomycin. Thus, although the phosphoinositide second messengers diacylglycerol and calcium probably play roles in mediating the effects of anti-IgM on WEHI-231 cells, other second messengers may also be involved.

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