Deoxycytidylate shortage is a cause of G1 arrest of ascites tumor cells under oxygen deficiency

Löffler, Monika; Schimpff-Weiland, Gabriele; Follmann, Hartmut

doi:10.1016/0014-5793(83)80251-8

Cited by 28 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figure 4, addition of deoxyadenine and deoxyguanine during various oxygen concentrations showed no effect on hypoxia-induced inhibition of cell cycle progression. This is in accordance with the earlier observation that the concentration of dATP remains unchanged dunrng hypoxia in Ehrlich ascites cells (Loffler et al, 1983). Furthermore, in the present study.…”

Section: Cell Proliferation During Extremely Hypoxic Conditionssupporting

confidence: 94%

“…To our knowledge no evidence points to possible oxygendependent steps and disturbances along the salvage pathway that could block the import and synthesis of pyrimidine deoxynucleotides under extremely hypoxic conditions. On the contrary it has been shown that the dCTP pool is threequarters restored by the addition of deoxycytidine under hypoxic conditions (Loffler et al, 1983). Therefore, the most likely explanation is that some sort of mechanism is activated or inactivated to prevent cells from the lethal effect of initiating DNA synthesis under conditions of extreme hypoxia.…”

Section: Cell Proliferation During Extremely Hypoxic Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Regulation of cell proliferation under extreme and moderate hypoxia: the role of pyrimidine (deoxy)nucleotides

Åmellem

Löffler²,

Pettersen³

1994

Br J Cancer

View full text Add to dashboard Cite

Sary In the present study we have used flow cytometric DNA measurements on synchronised human NHIK 3025 cells to measure cell cycle progression under various conditions of reduced oxygenation. Our data indicate that addition of 0.1 mm deoxycytidine or uridine has no effect on the oxygen-dependent arrest in late GI or on the inhibition of cell prolferation through S-phase under extremely hypoxic conditions. Following reoxygenation of cells exposed to extremely hypoxic conditions in G2 initiation of DNA synthesis in the subsequent cell cycle is delayed by several hours. This G2-induced delay is completely aboLshed for approximately 60% of the cell population by addition of deoxycytidine to hypoxic G2 cells. This finding supports our previous proposal that important steps in the preparation for DNA synthesis occur during G2 of the previous cell cycle, and it indicates that this preparation is connected to the de novo synthesis of pyrimidine deoxynucleotide precursors. The results show that cells are able to enter S-phase in the presence of 100-1,300 p.p.m. (0.01-0.13%) oxygen (here denoted 'moderate hypoxia'), but they are not able to complete DNA synthesis under such conditions. However, the cell cycle inhibition induced under moderate hypoxia is partially reversed in the presence of exogenously added deoxycytidine and uridine, while no such reversal is seen in the presence of purine deoxynucleosides (deoxyadenosine and deoxyguanosine). Thus, both deoxycytidine and uridine could replace reoxygenation under these conditions. These results indicate that the reduction of CDP to dCTP by nbnonucleotide reductase, an enzyme which requires oxygen as an essential factor for the formation of tyrosyl radicals for its catalytic activity, does not seem to be the limiting step responsible for the reduced dCTP pool observed under moderate hypoxia. We conclude that the oxygen-dependent catalytic activity of the M2 subunit of ribonucleotide reductase is still intact and functional in NHIK 3025 cells even at oxygen concentration as low as 100 p.p.m. Therefore, the cell cycle inhibition observed is probably due to inhibition of the respiratory chain-dependent UMP synthesis at the stage of dihydroorotate dehydrogenase.

show abstract

Section: Cell Proliferation During Extremely Hypoxic Conditionssupporting

confidence: 94%

Section: Cell Proliferation During Extremely Hypoxic Conditionsmentioning

confidence: 99%

Regulation of cell proliferation under extreme and moderate hypoxia: the role of pyrimidine (deoxy)nucleotides

Åmellem

Löffler²,

Pettersen³

1994

Br J Cancer

View full text Add to dashboard Cite

show abstract

“…Nevertheless, this additional regulatory significance of the dCTP pool was formerly suggested by Reichard on the basis of studies on replication of polyoma DNA [16], and is strongly supported by additional experimental evidence. E.g., restoring a normal dCTP pool in hypoxic cells by salvage [14,15,261 without resupplying 0, and without restoring the aerobic state of cellular RNR (this study) can substitute for reoxygenation with respect to the restoration of an aerobic situation of the cellular-replication machinery.…”

Section: Discussionmentioning

confidence: 92%

“…Cell cultures were treated as indicated. 15 min before the withdrawal of the first sample, [3H]dThd was added (25 nM, 0.4 pCi/ml). At the times indicated, samples (corresponding to 8 X lo6 cells) were transfered into cold Hanks solution and further processed as described in Materials and Methods.…”

Section: Relative Concentration Of the Tyrosyl Free Radical Of Rnr Inmentioning

confidence: 99%

“…10" cells cells-' . min-' Aerated control 5 h and 5 h, 15 the next 2 h. The dTTP pool of hypoxic cells was labeled to a distinctly higher specific radioactivity by external ['HIdThd than that of aerated (control) cells, as predicted earlier on the basis of bromodeoxy-uridine incorporation into the DNA of hypoxic cells [2]. On the other hand, the labeling of the dTTP pool by ['HIdThd 1 h after reoxygenation resulted in a diminished specific radioactivity relative to that of the aerated cells.…”

Section: Treatmentmentioning

confidence: 99%

See 1 more Smart Citation

Role of Ribonucleotide Reductase and Deoxynucleotide Pools in the Oxygen‐Dependent Control of DNA Replication in Ehrlich Ascites Cells

Brischwein

Engelcke

Riedinger

et al. 1997

European Journal of Biochemistry

View full text Add to dashboard Cite

Cultured Ehrlich ascites cells were exposed to different oxygen tensions (ranging from nearly complete anoxia to 95 % 0, at 1 O5 Pa) and to transient (5 -10 h) hypoxia (0.02 % 0, at 1 O5 Pa). Treated cells were examined with respect to the intracellular concentration of the M2-specific tyrosyl free radical of ribonucleotide reductase by EPR spectroscopy, and with respect to the pool sizes of all four deoxynucleoside triphosphates by an enzymatic assay employing DNA polymerase I of Escherichia coli. From 2% to 0.02% O,, the free radical level decreased continually from a normal value to just above detectability by the EPR measurement employed, and quickly recovered when hypoxic cells were resupplied with atmospheric 0,. Concurrently, analogous changes of the size of the dCTP pool occurred, whereas the pool sizes dATP and dGTP underwent no changes, and the size of the dTTP pool only moderate changes. The changes of the free radical concentration and of the dCTP pool correlated well with the suppression or reactivation of DNA replication under the respective 0, conditions. The results consistently support the hypothesis of a fast-acting regulatory pathway that controls the rate of DNA replication in proliferating cells according to sufficient availability of 0,. Therefore, ribonucleotide reductase may serve, in addition to providing DNA building blocks, as a PO, sensor, which transmits the signal in the form of an altered intracellular dCTP concentration, directly or indirectly, to the nuclear-replication machinery.Keywords: DNA replication ; regulation of DNA replication ; mammalian cells ; ribonucleotide reductase; deoxynucleotide pool.DNA replication in Ehrlich ascites cells has been demonstrated to be subject to a rapidly acting regulation that depends on the 0, in the cellular environment [1-61. This regulation responds at 0, tensions that are distinctly above that which significantly diminishes mitochondria1 respiration [3, 71 and at a normal adenylate energy charge [3].Work with cultured cells under controlled 0, tension (controlled hypoxia [l -61) revealed distinct changes in cellular DNA replication. When, in a typical transient-hypoxia experiment, the PO, is reduced 0.02-0.2% (relative to. 10' Pa total pressure), scheduled replicon initiations are specifically, reversibly and coordinately suppressed, whereas DNA-chain growth and maturation in replicons initiated before reduction of PO, continue normally. Reelevation of the PO, causes a subsequent burst of initiations. When the PO, is reduced to values below 0.01 5 % the fast reversibility of the depression of replication is lost [3]. By controlled hypoxia, scheduled replicon initiation can be reversibly suppressed in any stage of the S phase [3, 51. A constant high expression of genes directly related to the replicative state (e.g. thymidine kinase, proliferating cell nuclear antigen) is maintained when logarithmically growing Ehrlich ascites cells are subjected to several hours of controlled hypoxia [5]. Under Reoxygenation of such hypoxically accumula...

show abstract

Effect of some proliferative and environmental factors on the toxicity of mitomycin C to tumor cells in vitro

Rockwell

1986

Intl Journal of Cancer

View full text Add to dashboard Cite

Mitomycin C (MC) was more toxic to EMT6 mouse mammary tumor cells in vitro under hypoxia than under aerobic conditions. This was evidenced both in survival curves defining the toxicity of treatment with a constant dose of MC given for different periods of time and in survival curves defining the effect of a 1-hr treatment with different concentrations of MC. Cultures preincubated for different periods from 1 to 6 hr in hypoxia all had similar MC sensitivities. In contrast, cultures preincubated in hypoxia for 4 hr then "reoxygenated" before MC treatment had the same sensitivities as cultures which had never been hypoxic. This shows that the oxygenation at the time of MC exposure, rather than the preincubation protocol, was the parameter determining cell sensitivity. Exponentially-growing (proliferating) and plateau-phase (quiescent) cultures had similar MC survival curves; neither type of culture repaired potentially lethal damage when held for up to 24 hr in HBSS after MC treatment. The sensitivity of the cells increased as the pH of the culture medium was decreased to low values (pH 7.0-6.0), but extracellular pH had no significant effect on the cytotoxicity of MC over the physiologic range (7.0-7.4). These data suggest that differences in the metabolic characteristics of cells that are hypoxic and aerobic during MC treatment, rather than perturbations of the cell proliferation patterns, the PLDR capacity of the cells, or the extracellular pH during the hypoxic incubation, are responsible for the different sensitivities of aerobic and hypoxic cells to MC in vitro.

show abstract

Deoxycytidylate shortage is a cause of G1 arrest of ascites tumor cells under oxygen deficiency

Abstract: not received Cell cycleAnaerobiosis Deoxyribonucleotide pool Ribonucleotide reduction

Cited by 28 publications

References 15 publications

Regulation of cell proliferation under extreme and moderate hypoxia: the role of pyrimidine (deoxy)nucleotides

Regulation of cell proliferation under extreme and moderate hypoxia: the role of pyrimidine (deoxy)nucleotides

Role of Ribonucleotide Reductase and Deoxynucleotide Pools in the Oxygen‐Dependent Control of DNA Replication in Ehrlich Ascites Cells

Effect of some proliferative and environmental factors on the toxicity of mitomycin C to tumor cells in vitro

Contact Info

Product

Resources

About