scholarly journals Induction of human choriogonadotropin in HeLa-cell cultures by aliphatic monocarboxylates and inhibitors of deoxyribonucleic acid synthesis

1977 ◽  
Vol 166 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Nimai K. Ghosh ◽  
Adriana Rukenstein ◽  
Rody P. Cox
Keyword(s):  
Protein Synthesis ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Hela Cells ◽  
Fold Increase ◽  
Short Chain Fatty Acids ◽  
Acid Synthesis ◽  
Hydroxyl Groups ◽  
Β Subunit ◽  
Inhibitor Of Protein Synthesis

The ectopic production of the glycopeptide hormone human placental choriogonadotropin by HeLa65 cells was measured by radioimmunoassay with antiserum against the β-subunit of choriogonadotropin and with the125I-labelled β-subunit as a tracer antigen. Choriogonadotropin synthesis was markedly (500-fold) stimulated by sodium butyrate. Kinetic studies and the use of an inhibitor of protein synthesis, cycloheximide, indicated that protein synthesis was required for this induction. Investigation of the efficiency of 22 aliphatic short-chain fatty acids and derivatives in causing increased choriogonadotropin synthesis by HeLa cells showed stringent structural requirements. Induction of choriogonadotropin synthesis in HeLa cells was not restricted to butyrate. Other aliphatic acids (propionate, isobutyrate, valerate and hexanoate) were also capable of inducing choriogonadotropin synthesis at 10–50% of the efficiency of butyrate. Hydroxy derivatives of monocarboxylate inducers, related mono- and di-carboxylic acids, alcohols, amines, ketones, esters and sulphoxide were ineffective in increasing choriogonadotropin production by HeLa cells. A saturated C4 straight-chain acid without substituent hydroxyl groups but with a methyl group at one end and a carboxyl moiety at the other appeared to be most efficient in activating choriogonadotropin production. A second clonal line of HeLa cells, HeLa71, showed a higher constitutive synthesis of choriogonadotropin than HeLa65 cells, which was also markedly increased by butyrate. Butyrate and other aliphatic monocarboxylate inducers of choriogonadotropin synthesis inhibited HeLa-cell growth and DNA synthesis. This inhibition of DNA replication may be related to the mechanism of choriogonadotropin synthesis, since two well-characterized anti-neoplastic inhibitors of DNA synthesis, hydroxyurea and 1-β-d-arabinofuranosylcytosine, also stimulated a 300-fold increase in choriogonadotropin synthesis in HeLa cells and were synergistic with butyrate in promoting choriogonadotropin synthesis. Thus activation in tumour cells of genes normally expressed by foetal tissue and the consequent ectopic synthesis of polypeptide hormones may require neither cell division nor DNA synthesis.

scholarly journals LIMITED DNA SYNTHESIS IN THE ABSENCE OF PROTEIN SYNTHESIS IN PHYSARUM POLYCEPHALUM

1966 ◽  
Vol 31 (3) ◽  
pp. 577-583 ◽  
Author(s):  
J. E. Cummins ◽  
H. P. Rusch
Keyword(s):  
Protein Synthesis ◽  
Dna Replication ◽  
Dna Synthesis ◽  
Physarum Polycephalum ◽  
Nuclear Dna ◽  
S Phase ◽  
Early Prophase ◽  
Late Prophase ◽  
Removal Experiments ◽  
Inhibitor Of Protein Synthesis

Actidione (cycloheximide), an antibiotic inhibitor of protein synthesis, blocked the incorporation of leucine and lysine during the S phase of Physarum polycephalum. Actidione added during the early prophase period in which mitosis is blocked totally inhibited the initiation of DNA synthesis. Actidione treatment in late prophase, which permitted mitosis in the absence of protein synthesis, permitted initiation of a round of DNA replication making up between 20 and 30% of the unreplicated nuclear DNA. Actidione treatment during the S phase permitted a round of replication similar to the effect at the beginning of S. The DNA synthesized in the presence of actidione was replicated semiconservatively and was stable through at least the mitosis following antibiotic removal. Experiments in which fluorodeoxyuridine inhibition was followed by thymidine reversal in the presence of actidione suggest that the early rounds of DNA replication must be completed before later rounds are initiated.

scholarly journals MACROPHAGE-MELANOMA CELL HETEROKARYONS

1971 ◽  
Vol 134 (4) ◽  
pp. 935-946 ◽  
Author(s):  
Saimon Gordon ◽  
Zanvil Cohn
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Melanoma Cell ◽  
Melanoma Cells ◽  
Irreversible Inhibitor ◽  
Cell Pretreatment ◽  
Lag Period ◽  
Inhibitor Of Protein Synthesis ◽  
Physical Changes ◽  
The Relationship

Dormant macrophage nuclei initiate DNA synthesis 2–3 hr after fusion of macrophages with exponentially growing melanoma cells. Cycloheximide treatment (1–5 µg/ml) of heterokaryons during the preceding lag period inhibits the initiation of macrophage DNA synthesis, in a reversible fashion. Each type of cell was also treated with streptovitacin A, an irreversible inhibitor of protein synthesis. Pretreatment of the melanoma cells (0.5–2 µg/ml), 1 hr before fusion, inhibited the induction of macrophage DNA synthesis in heterokaryons, whereas pretreatment of macrophages (1–20 µg/ml) had no effect. Melanoma cell pretreatment reduced the incorporation of leucine-3H into the cytoplasm and nuclei of heterokaryons, whereas macrophage pretreatment had no effect. These experiments suggested that melanoma proteins played an important role in the initiation of macrophage DNA synthesis. The relationship between the melanoma cell cycle and macrophage DNA synthesis was studied with synchronous melanoma cells. If the melanoma cells were in S phase at the time of fusion, macrophage DNA synthesis occurred 2 hr later. However, the fusion of melanoma cells in G1 delayed macrophage DNA synthesis until the melanoma nuclei had entered S. Experiments with actinomycin and cycloheximide showed that RNA and protein, essential to achieve DNA synthesis in the macrophage nucleus, were made during late G1 as well as S. Melanoma cells and macrophages differ in their radiolabeled acid-soluble products after incubation in thymidine-3H. Thymidine taken up by the macrophage remained unphosphorylated, whereas it was recovered mainly as thymidine triphosphate from melanoma cells. These findings, as well as those reported previously, suggest that the melanoma cell provides the RNA, protein, and precursors which initiate macrophage DNA synthesis. In the absence of a requirement for new macrophage RNA and protein synthesis, other changes must be responsible for the 2 hr delay in DNA synthesis. These may involve physical changes in DNA, associated with swelling, as well as the transport of melanoma products into the macrophage nucleus.

scholarly journals Investigations of the Mode of Action and Resistance Development of Cadazolid, a New Antibiotic for Treatment of Clostridium difficile Infections

2013 ◽  
Vol 58 (2) ◽  
pp. 901-908 ◽  
Author(s):  
Hans H. Locher ◽  
Patrick Caspers ◽  
Thierry Bruyère ◽  
Susanne Schroeder ◽  
Philippe Pfaff ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Clostridium Difficile ◽  
Dna Synthesis ◽  
Mode Of Action ◽  
Cross Resistance ◽  
Resistance Development ◽  
Content Type ◽  
Inhibition Of Protein Synthesis ◽  
Inhibitor Of Protein Synthesis ◽  
Inhibition Of Dna Synthesis

ABSTRACTCadazolid is a new oxazolidinone-type antibiotic currently in clinical development for the treatment ofClostridium difficile-associated diarrhea. Here, we report investigations on the mode of action and the propensity for spontaneous resistance development inC. difficilestrains. Macromolecular labeling experiments indicated that cadazolid acts as a potent inhibitor of protein synthesis, while inhibition of DNA synthesis was also observed, albeit only at substantially higher concentrations of the drug. Strong inhibition of protein synthesis was also obtained in strains resistant to linezolid, in agreement with low MICs against such strains. Inhibition of protein synthesis was confirmed in coupled transcription/translation assays using extracts from differentC. difficilestrains, including strains resistant to linezolid, while inhibitory effects in DNA topoisomerase assays were weak or not detectable under the assay conditions. Spontaneous resistance frequencies of cadazolid were low in all strains tested (generally <10−10at 2× to 4× the MIC), and in multiple-passage experiments (up to 13 passages) MICs did not significantly increase. Furthermore, no cross-resistance was observed, as cadazolid retained potent activity against strains resistant or nonsusceptible to linezolid, fluoroquinolones, and the new antibiotic fidaxomicin. In conclusion, the data presented here indicate that cadazolid acts primarily by inhibition of protein synthesis, with weak inhibition of DNA synthesis as a potential second mode of action, and suggest a low potential for spontaneous resistance development.

scholarly journals Anticancer Effects of Propionic Acid Inducing Cell Death in Cervical Cancer Cells

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4951
Author(s):  
Chau-Ha Pham ◽  
Joo-Eun Lee ◽  
Jinha Yu ◽  
Sung-Hoon Lee ◽  
Kyung-Rok Yu ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cell Death ◽  
Hela Cell ◽  
Cell Viability ◽  
Propionic Acid ◽  
Hela Cells ◽  
Cancer Therapeutics ◽  
Short Chain Fatty Acids ◽  
Bacterial Fermentation ◽  
Protein Levels

Recent studies found that short-chain fatty acids (SCFAs), which are produced through bacterial fermentation in the gastrointestinal tract, have oncoprotective effects against cervical cancer. The most common SCFAs that are well known include acetic acid, butyric acid, and propionic acid, among which propionic acid (PA) has been reported to induce apoptosis in HeLa cells. However, the mechanism in which SCFAs suppress HeLa cell viability remain poorly understood. Our study aims to provide a more detailed look into the mechanism of PA in HeLa cells. Flow cytometry analysis revealed that PA induces reactive oxygen species (ROS), leading to the dysfunction of the mitochondrial membrane. Moreover, PA inhibits NF-κB and AKT/mTOR signaling pathways and induces LC3B protein levels, resulting in autophagy. PA also increased the sub-G1 cell population that is characteristic of cell death. Therefore, the results of this study propose that PA inhibits HeLa cell viability through a mechanism mediated by the induction of autophagy. The study also suggests a new approach for cervical cancer therapeutics.

scholarly journals THE CENTRIOLE CYCLE IN SYNCHRONIZED HELA CELLS

1968 ◽  
Vol 36 (2) ◽  
pp. 329-339 ◽  
Author(s):  
Elliott Robbins ◽  
Gisela Jentzsch ◽  
Anita Micali
Keyword(s):  
Life Cycle ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Hela Cells ◽  
Late Prophase ◽  
Tubule Formation

Progression of the HeLa cell through its life cycle is accompanied by centriolar replication and pericentriolar changes that are in synchrony with DNA synthesis and mitosis. The first signs of preparation for replication occur during G1 at which time the two orthogonal centrioles separate. Replication by budding begins at/or near the initiation of DNA synthesis and is completed by G2. Pericentriolar changes which probably are causally related to spindle tubule formation occur at this time and include the appearance of vesicles, electron-opaque bodies, and an amorphous pericentriolar halo. These phenomena begin to disappear by late prophase, and the remainder of mitosis manifests decreasing centriolar and pericentriolar activity.

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 Cytochalasin releases mRNA from the cytoskeletal framework and inhibits protein synthesis.

1986 ◽  
Vol 6 (5) ◽  
pp. 1650-1662 ◽  
Author(s):  
D A Ornelles ◽  
E G Fey ◽  
S Penman
Keyword(s):  
Protein Synthesis ◽  
Hela Cells ◽  
Cell Structure ◽  
Cytochalasin D ◽  
Reversible Inhibitor ◽  
Dependent Manner ◽  
Inhibitor Of Protein Synthesis ◽  
Cytoskeletal Elements ◽  
Mrna Binding

Cytochalasin D was shown to be a reversible inhibitor of protein synthesis in HeLa cells. The inhibition was detectable at drug levels typically used to perturb cell structure and increased in a dose-dependent manner. The drug also released mRNA from the cytoskeletal framework in direct proportion to the inhibition of protein synthesis. The released mRNA was unaltered in its translatability as measured in vitro but was no longer translated in the cytochalasin-treated HeLa cells. The residual protein synthesis occurred on polyribosomes that were reduced in amount but displayed a normal sedimentation distribution. The results support the hypothesis that mRNA binding to the cytoskeletal framework is necessary although not sufficient for translation. Analysis of the cytoskeletal framework, which binds the polyribosomes, revealed no alterations in composition or amount of protein as a result of treatment with cytochalasin D. Electron microscopy with embedment-free sections shows the framework in great detail. The micrographs revealed the profound reorganization effected by the drug but did not indicate substantial disaggregation of the cytoskeletal elements.

scholarly journals Cytotoxic activity of Pinus cembra L. needle extract: A preliminary study on HeLa cell line

2021 ◽  
Vol 57 (2) ◽  
pp. 93-98
Author(s):  
Cristina LUNGU ◽  
◽  
Cosmin-Teodor MIHAI ◽  
Gabriela VOCHITA ◽  
Daniela GHERGHEL ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Hela Cell ◽  
Cell Line ◽  
Hela Cells ◽  
Pine Needles ◽  
Hela Cell Line ◽  
Pine Needle ◽  
Cytotoxic Effects ◽  
Antitumor Potential ◽  
Cembran Pine

The aim of this study was to investigate the cytotoxic effects of a hydromethanolic extract obtained from cembran pine needles in HeLa cell line. In this respect, the effects of needle extract on protein synthesis, viability, proliferation and cell cycle in HeLa cells were evaluated after 48 h treatment. Cembran pine needle extract dose-dependently decreased protein synthesis in HeLa cells causing 44.26% reduction in protein synthesis at 100µg/ml. At 25, 50 and 100µg/ml, it increased cell death in comparison with the control (20.99%, 21.49% and 23.63%, respectively vs. 9.83%). In addition, at 100µg/ml, cembran pine needle extract showed a remarkable antiproliferative effect whereas at 25 and 50µg/ml, it induced sub-G1 phase cells accumulation (11.68 ± 0.81% and 14.69 ± 0.56%, respectively in comparison with control, 6.03 ± 0.55%), an indicator of proapoptotic effects. Taken together, these results indicate that cembran pine needles are a source of compounds with antitumor potential which needs to be further investigated and exploited.

Cytochalasin releases mRNA from the cytoskeletal framework and inhibits protein synthesis

1986 ◽  
Vol 6 (5) ◽  
pp. 1650-1662
Author(s):  
D A Ornelles ◽  
E G Fey ◽  
S Penman
Keyword(s):  
Protein Synthesis ◽  
Hela Cells ◽  
Cell Structure ◽  
Cytochalasin D ◽  
Reversible Inhibitor ◽  
Dependent Manner ◽  
Inhibitor Of Protein Synthesis ◽  
Cytoskeletal Elements ◽  
Mrna Binding

Cytochalasin D was shown to be a reversible inhibitor of protein synthesis in HeLa cells. The inhibition was detectable at drug levels typically used to perturb cell structure and increased in a dose-dependent manner. The drug also released mRNA from the cytoskeletal framework in direct proportion to the inhibition of protein synthesis. The released mRNA was unaltered in its translatability as measured in vitro but was no longer translated in the cytochalasin-treated HeLa cells. The residual protein synthesis occurred on polyribosomes that were reduced in amount but displayed a normal sedimentation distribution. The results support the hypothesis that mRNA binding to the cytoskeletal framework is necessary although not sufficient for translation. Analysis of the cytoskeletal framework, which binds the polyribosomes, revealed no alterations in composition or amount of protein as a result of treatment with cytochalasin D. Electron microscopy with embedment-free sections shows the framework in great detail. The micrographs revealed the profound reorganization effected by the drug but did not indicate substantial disaggregation of the cytoskeletal elements.

scholarly journals Carcinogenesis and Cellular Injury. The effect of ethionine on ribonucleic acid synthesis in rat liver

1975 ◽  
Vol 150 (3) ◽  
pp. 335-344 ◽  
Author(s):  
P F Swann ◽  
A C Peacock ◽  
S Bunting
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Female Rat ◽  
Concurrent Administration ◽  
Polyamine Synthesis ◽  
Rrna Maturation ◽  
Precursor Rna ◽  
Inhibitor Of Protein Synthesis ◽  
Ribosomal Precursor

1. By 1h after administration of ethionine to the female rat the appearance of newly synthesized 18SrRNA in the cytoplasm is completely inhibited. This is not caused by inhibition of RNA synthesis, for the synthesis of the large ribosomal precursor RNA (45S) and of tRNA continues. Cleavage of 45S RNA to 32S RNA also occurs, but there was no evidence for the accumulation of mature or immature rRNA in the nucleus. 2. The effect of ethionine on the maturation of rRNA was not mimicked by an inhibitor of protein synthesis (cycloheximide) or an inhibitor of polyamine synthesis [methylglyoxal bis(guanylhydrazone)]. 3. Unlike the ethionine-induced inhibition of protein synthesis, this effect was not prevented by concurrent administration of inosine. A similar effect could be induced in HeLa cells by incubation for 1h in a medium lacking methionine. The ATP concentration in these cells was normal. From these two observations it was concluded that the effect of etionine on rRNA maturation is not caused by an ethionine-induced lack of ATP. It is suggested that ethionine, by lowering the hepatic concentration of S-adenosylmethionine, prevents methylation of the ribosomal precursor. The methylation is essential for the correct maturation of the molecule; without methylation complete degradation occurs.

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