Inhibition of DNA Synthesis and G 1 /S-Phase Transition in Normal Human Fibroblasts Elicited by a Heat-Labile Trans-Acting Factor in Gamma-Irradiated HeLa Cell Extracts

1997 ◽  
Vol 147 (1) ◽  
pp. 13 ◽  
Author(s):  
Razmik Mirzayans ◽  
Louise Enns ◽  
Malcolm C. Paterson
Keyword(s):  
Phase Transition ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Human Fibroblasts ◽  
S Phase ◽  
Cell Extracts ◽  
Heat Labile ◽  
Normal Human ◽  
Gamma Irradiated ◽  
Inhibition Of Dna Synthesis

scholarly journals Intracellular free Ca2+ in the cell cycle in human fibroblasts: transitions between G1 and G0 and progression into S phase.

1993 ◽  
Vol 4 (3) ◽  
pp. 293-302 ◽  
Author(s):  
M Wahl ◽  
E Gruenstein
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Dose Response ◽  
Human Fibroblasts ◽  
S Phase ◽  
Free Calcium ◽  
Response Curves ◽  
Serum Stimulation ◽  
Inhibition Of Dna Synthesis ◽  
Stimulation Of

Intracellular free calcium ([Ca2+]i) has been proposed to play an important part in the regulation of the cell cycle. Although a number of studies have shown that stimulation of quiescent cells with growth factors causes an immediate rise in [Ca2+]i (Rabinovitch et al., 1986; Vincentini and Villereal, 1986; Hesketh et al., 1988; Tucker et al., 1989, Wahl et al., 1990), a causal relationship between the [Ca2+]i transient and the ability of the cells to reenter the cell cycle has not been firmly established. We have found that blocking the mitogen-induced elevation of [Ca2+]i with the cytoplasmic [Ca2+]i buffer dimethyl BAPTA (dmBAPTA) also blocks subsequent entry of cells into S phase. The dose response curves for inhibition of serum stimulation of [Ca2+]i and DNA synthesis by dmBAPTA are virtually identical including an anomalous stimulation observed at low levels of dmBAPTA. Reversal of the [Ca2+]i buffering effect of dmBAPTA by transient exposure of the cells to the Ca2+ ionophore ionomycin also reverses the inhibition of DNA synthesis 20-24 h later. Ionomycin by itself does not stimulate DNA synthesis. These data are consistent with the conclusion that a transient increase in [Ca2+]i occurring shortly after serum stimulation of quiescent fibroblasts is necessary but not sufficient for subsequent entry of the cells into S phase. This study is the first to show a direct relationship between early serum stimulated Cai2+ increase and subsequent DNA synthesis in human cells. It also goes beyond recent studies on BALB/3T3 cells by providing dose response data and demonstrating reversibility, which are strong indications of a cause and effect relationship.

Interferon inhibition of DNA synthesis and cell division

1972 ◽  
Vol 18 (2) ◽  
pp. 145-151 ◽  
Author(s):  
M. V. O'Shaughnessy ◽  
S. H. S. Lee ◽  
K. R. Rozee
Keyword(s):  
Cell Division ◽  
Antiviral Activity ◽  
Dna Synthesis ◽  
S Phase ◽  
Cell Suspensions ◽  
Depression Effect ◽  
Growth Depression ◽  
Synchronized Cells ◽  
Inhibition Of Dna Synthesis ◽  
New Protein

Using monodispersed cell suspensions, interferon preparations were shown to have both a lethal and a growth-depression effect in the same concentration range as that required for antiviral activity. In addition, synchronized cells treated with interferon respond by delaying their normal uptake of thymidine during S phase until after a period during which new protein is synthesized. Puromycin added during this period prevents both the synthesis of this protein and the subsequent synthesis of DNA.

scholarly journals Adenovirus E1B 55-Kilodalton Protein Is Required for both Regulation of mRNA Export and Efficient Entry into the Late Phase of Infection in Normal Human Fibroblasts

2006 ◽  
Vol 80 (2) ◽  
pp. 964-974 ◽  
Author(s):  
Ramon Gonzalez ◽  
Wenying Huang ◽  
Renee Finnen ◽  
Courtney Bragg ◽  
S. J. Flint
Keyword(s):  
Dna Synthesis ◽  
Hela Cells ◽  
Human Fibroblasts ◽  
Late Phase ◽  
Mrna Export ◽  
Human Cells ◽  
Insertion Mutation ◽  
Viral Dna ◽  
Normal Human ◽  
Normal Human Cells

ABSTRACT The human adenovirus type 5 (Ad5) E1B 55-kDa protein is required for selective nuclear export of viral late mRNAs from the nucleus and concomitant inhibition of export of cellular mRNAs in HeLa cells and some other human cell lines, but its contributions(s) to replication in normal human cells is not well understood. We have therefore examined the phenotypes exhibited by viruses carrying mutations in the E1B 55-kDa protein coding sequence in normal human fibroblast (HFFs). Ad5 replicated significantly more slowly in HFFs than it does in tumor cells, a difference that is the result of delayed entry into the late phase of infection. The A143 mutation, which specifically impaired export of viral late mRNAs from the nucleus in infected HeLa cells (R. A. Gonzalez and S. J. Flint, J. Virol. 76:4507-4519, 2002), induced a more severe defect in viral mRNA export in HFFs. This observation indicates that the E1B 55-kDa protein regulates mRNA export during the late phase of infection of normal human cells. Other mutants exhibited phenotypes not observed in HeLa cells. In HFFs infected by the null mutant Hr6, synthesis of viral late mRNAs and proteins was severely impaired. Such defects in late gene expression were the result of inefficient progression into the late phase of infection, for viral DNA synthesis was 10-fold less efficient in Hr6-infected HFFs than in cells infected by Ad5. Similar, but less severe, defects in viral DNA synthesis were induced by the insertion mutation H224, which has been reported to inhibit binding of the E1B 55-kDa protein to p53 (C. C. Kao, P. R. Yew, and A. J. Berk, Virology 179:806-814, 1990).

Induction of Cyclin E and Inhibition of DNA Synthesis by the Novel Acronycine Derivative S23906-1 Precede the Irreversible Arrest of Tumor Cells in S Phase Leading to Apoptosis

2001 ◽  
Vol 60 (6) ◽  
pp. 1383-1391 ◽  
Author(s):  
Stéphane Léonce ◽  
Valérie Pérez ◽  
Stéphanie Lambel ◽  
Delphine Peyroulan ◽  
François Tillequin ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Tumor Cells ◽  
Cyclin E ◽  
S Phase ◽  
The Novel ◽  
Inhibition Of Dna Synthesis

Hydroxyurea: Inhibition of DNA-Synthesis and Selective Susceptibility of S-Phase Cells In Vivo

1967 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
F. S. Philips ◽  
H. S. Schwartz ◽  
S. S. Sternberg
Keyword(s):  
Dna Synthesis ◽  
Renal Excretion ◽  
Tissue Concentration ◽  
Tritiated Thymidine ◽  
S Phase ◽  
Cell Renewal ◽  
Cytotoxic Effects ◽  
Inhibition Of Dna Synthesis ◽  
Physiological Disposition

SummaryThe cytotoxic effects of hydroxyurea and of related hydroxamic acid derivatives in vivo are briefly described. They occur selectively in tissues with high rates of cell renewal and they are of brief duration. Tissue concentration of hydroxyurea diminish rapidly as the result of renal excretion and metabolism; there is a close temporal relation between the physiological disposition of the agents and the cytotoxic changes. Hydroxyurea induces an immediate inhibition of DNA synthesis in proliferating tisdsues such as thymus, small intestine, and regenerating liver. Autoradiographic studies of mouse duodenum using tritiated thymidine have shown that the lethal susceptibility to hydroxyurea is restricted to cells in the S-phase of the mitotic cycles. Cells in G1, G2, and M are not damaged by the agent.

scholarly journals Transient inhibition of DNA synthesis results in increased dihydrofolate reductase synthesis and subsequent increased DNA content per cell.

1986 ◽  
Vol 6 (10) ◽  
pp. 3373-3381 ◽  
Author(s):  
R N Johnston ◽  
J Feder ◽  
A B Hill ◽  
S W Sherwood ◽  
R T Schimke
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Gene Amplification ◽  
Dihydrofolate Reductase ◽  
Dna Content ◽  
S Phase ◽  
Phase Cell ◽  
Drug Inhibition ◽  
Specific Proteins ◽  
Inhibition Of Dna Synthesis

We examined the role that blockage of cells in the cell cycle may play in the stimulation of gene amplification and enhancement of drug resistance. We found that several different inhibitors of DNA synthesis, which were each able to block cells at the G1-S-phase boundary, induced an enhanced cycloheximide-sensitive synthesis of an early S-phase cell cycle-regulated enzyme, dihydrofolate reductase, and of other proteins as well. This response was specific, in that blockage at the G2 phase did not result in overproduction of the enzyme. When the cells were released from drug inhibition, DNA synthesis resumed, resulting in a cycloheximide-sensitive elevation in DNA content per cell. We speculate that the excess DNA synthesis (which could contribute to events detectable later as gene amplification) is a consequence of the accumulation of S-phase-specific proteins in the affected cells, which may then secondarily influence the pattern of DNA replication.

scholarly journals Regulation of human histone gene expression: kinetics of accumulation and changes in the rate of synthesis and in the half-lives of individual histone mRNAs during the HeLa cell cycle.

1983 ◽  
Vol 3 (4) ◽  
pp. 539-550 ◽  
Author(s):  
N Heintz ◽  
H L Sive ◽  
R G Roeder
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Fold Increase ◽  
S Phase ◽  
Histone Mrna ◽  
Mrna Accumulation ◽  
Histone Mrnas ◽  
The Individual ◽  
Kinetics Of

We have analyzed the kinetics of accumulation of each of the individual core histone mRNAs throughout the HeLa cell cycle in cells synchronized by sequential thymidine and aphidicolin treatments. These analyses showed that during the S phase there was a 15-fold increase in the levels of histone mRNAs and that this resulted from both an increased rate of synthesis and a lengthening of the half-life of histone mRNAs. A comparison of the kinetics of accumulation of histone mRNA in the total cellular and nuclear RNA populations suggested an increased transcription rate through the S phase. Within 30 min after the inhibition of DNA synthesis in mid-S phase, the steady-state concentration and the rate of synthesis of histone mRNA each declined to their non-S-phase levels. Reactivation of histone mRNA accumulation could occur even after an extended mid-S-phase block in DNA synthesis. These results suggest that the mechanisms responsible for histone mRNA synthesis are not restricted to the G1/S boundary of the HeLa cell cycle, but can operate whenever DNA synthesis is occurring.

scholarly journals cAMP-mediated Inhibition of DNA Replication and S Phase Progression: Involvement of Rb, p21Cip1, and PCNA

2005 ◽  
Vol 16 (3) ◽  
pp. 1527-1542 ◽  
Author(s):  
Soheil Naderi ◽  
Jean Y.J. Wang ◽  
Tung-Ti Chen ◽  
Kristine B. Gutzkow ◽  
Heidi K. Blomhoff
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Cellular Proliferation ◽  
Kinase Activity ◽  
Antitumor Agents ◽  
Cell Types ◽  
S Phase ◽  
3T3 Fibroblasts ◽  
Phase Progression ◽  
Inhibition Of Dna Synthesis

cAMP exerts an antiproliferative effect on a number of cell types including lymphocytes. This effect of cAMP is proposed to be mediated by its ability to inhibit G1/S transition. In this report, we provide evidence for a new mechanism whereby cAMP might inhibit cellular proliferation. We show that elevation of intracellular levels of cAMP inhibits DNA replication and arrests the cells in S phase. The cAMP-induced inhibition of DNA synthesis was associated with the increased binding of p21Cip1to Cdk2-cyclin complexes, inhibition of Cdk2 kinase activity, dephosphorylation of Rb, and dissociation of PCNA from chromatin in S phase cells. The ability of cAMP to inhibit DNA replication and trigger release of PCNA from chromatin required Rb and p21Cip1proteins, since both processes were only marginally affected by increased levels of cAMP in Rb-/-and p21Cip1-/-3T3 fibroblasts. Importantly, the implications of cAMP-induced inhibition of DNA synthesis in cancer treatment was demonstrated by the ability of cAMP to reduce apoptosis induced by S phase–specific cytotoxic drugs. Taken together, these results demonstrate a novel role for cAMP in regulation of DNA synthesis and support a model in which activation of cAMP-dependent signaling protects cells from the effect of S phase–specific antitumor agents.

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