DNA SYNTHESIS IN THE ENDOMETRIUM OF PROGESTERONE-TREATED MICE

1973 ◽  
Vol 56 (2) ◽  
pp. 303-307 ◽  
Author(s):  
L. MARTIN ◽  
C. A. FINN ◽  
GAIL TRINDER
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Stromal Cells ◽  
Single Injection ◽  
Morphological Changes ◽  
Glandular Epithelium ◽  
Nuclear Morphology ◽  
Luminal Epithelium ◽  
Thymidine Autoradiography

SUMMARY [3H]Thymidine autoradiography was used to study DNA synthesis in the uteri of spayed mice treated with progesterone and oestradiol. Progesterone suppressed DNA synthesis in the glandular epithelium whether oestrogen was given or not. It also suppressed DNA synthesis in the luminal epithelium. Here oestradiol produced morphological changes and eventual re-entry of some cells into DNA synthesis. Progesterone altered the nuclear morphology of the stromal cells and increased the number synthesizing DNA. In these conditions a single injection of oestrogen was followed 10–15 h later by the synchronized entry into DNA synthesis of 30–40% of stromal cells. However, a second injection produced no further response. It was concluded that progesterone stimulated stromal cells in the resting phase to enter the cell cycle and that oestrogen then accelerated their passage through a single round of replication and division by shortening the interval between mitosis and DNA synthesis, following which the cells withdrew from the cell cycle.

CHANGES IN CELL PROLIFERATION RATE IN MOUSE UTERINE EPITHELIUM DURING CONTINUOUS OESTROGEN TREATMENT

1974 ◽  
Vol 61 (1) ◽  
pp. 117-121 ◽  
Author(s):  
AUDREY E. LEE ◽  
L. A. ROGERS ◽  
GAIL TRINDER
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Synthesis ◽  
Mitotic Index ◽  
Cycle Time ◽  
Luminal Epithelium ◽  
Cell Cycle Time ◽  
Oestrogen Treatment ◽  
Probability Of Transition ◽  
The Mean

SUMMARY Fraction of labelled mitoses (FLM) curves were constructed for mouse uterine luminal epithelium during oestradiol treatment; on day 2 when mitosis was high, and on days 4 and 9 when mitosis was low. No difference was found between the duration of DNA synthesis on these 3 days. The distance between the first and second peaks, usually taken as an estimate of the mean cell cycle time, did not change significantly between days 2 and 4, although the labelling index fell from 38 to 8%. The second peaks of the FLM curves became progressively lower on the three days examined, which was consistent with the interpretation that there was a reduction in the probability of transition of cells from G1 (the post-mitotic period) into the replicative phase of the cell cycle, resulting in the observed fall in mitotic index.

Effets du lindane sur la division, le cycle cellulaire et les biosynthèses de deux Algues unicellulaires

1979 ◽  
Vol 57 (13) ◽  
pp. 1464-1472 ◽  
Author(s):  
N. Jeanne
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Golgi Apparatus ◽  
Dna Synthesis ◽  
Dark Period ◽  
Morphological Changes ◽  
Cell Content ◽  
Unicellular Algae ◽  
Protein Cell

The lindane or hexachlorocyclohexane γ isomer inhibited cell division in two cultivated unicellular algae and caused morphological changes of enlarged cells; increase of the golgi apparatus, endomultiplication of the organelles, abnormal partition of nuclei, and a decrease in the number of microtubules were observed. However, lindane did not change the polymerization of tubulin in vitro. In synchronously dividing Dunaliella bioculata, mitosis could be blocked even if the insecticide was added to cultures after the beginning of the outburst of cell division during the dark period. During the first cell cycle, the RNA and protein cell content increased more slowly in treated cells and then continued to increase more or less rapidly during the second cell cycle. The DNA synthesis was strongly inhibited by 10 μg/mL of lindane and depressed by 5 μg/mL as early as the first cell cycle. The synthesis did not resume during the second cell cycle.

Modulation effects of hexamethylene bisacetamide on growth and differentiation of cultured human malignant glioma cells

1996 ◽  
Vol 84 (5) ◽  
pp. 831-838 ◽  
Author(s):  
Xiao-Nan Li ◽  
Zi-Wei Du ◽  
Qiang Huang
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Malignant Glioma ◽  
Culture Media ◽  
Morphological Changes ◽  
Control Group ◽  
Cell Cycle Distribution ◽  
Content Type ◽  
Hexamethylene Bisacetamide ◽  
Human Malignant Glioma

✓ The modulation effects of hexamethylene bisacetamide (HMBA), a differentiation-inducing agent, on growth and differentiation of cells from human malignant glioma cell line SHG-44 were studied. At cytostatic doses (2.5 mM, 5 mM, 7.5 mM, and 10 mM for 15 days), HMBA exerted a marked inhibitory effect on cell proliferation. Exposure to HMBA (5 mM and 10 mM for 12 days) also resulted in an accumulation of cells in G0/G1 phase and a decrease of cells in S phase as analyzed by flow cytometry. The reversible effects of 7.5 mM HMBA and 10 mM HMBA on cell proliferation and 10 mM HMBA on disruption of cell cycle distribution were observed when HMBA was removed from culture media on Day 6 and replaced with HMBA-free media. Colony-forming efficiency (CFE) in soft agar was remarkably decreased by HMBA (2.5 mM, 5 mM, 7.5 mM, and 10 mM for 14 days), and in 7.5 mM HMBA— and 10 mM HMBA—treated cells, the CFEs were reduced to 25% and 12.5%, respectively, of that in untreated cells. Cells treated with HMBA (5 mM and 10 mM for 15 days) remained tumorigenic in athymic nude mice, but the growth rates of the xenografts were much slower than those in the control group. The effects of HMBA on cell proliferation, cell cycle distribution, CFE, and growth of xenografts were dose dependent. A more mature phenotype was confirmed by the morphological changes from spindle shape to large polygonal stellate shape and remarkably elevated expression of glial fibrillary acidic protein in cells exposed to HMBA (5 mM, 10 mM for 15 days). Our results showed that a more differentiated phenotype with marked growth arrest was induced in SHG-44 cells by HMBA.

scholarly journals High-intensity Raf signal causes cell cycle arrest mediated by p21Cip1.

1997 ◽  
Vol 17 (9) ◽  
pp. 5588-5597 ◽  
Author(s):  
A Sewing ◽  
B Wiseman ◽  
A C Lloyd ◽  
H Land
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Cell Cycle Arrest ◽  
Expression Patterns ◽  
Cellular Responses ◽  
Specific Cell ◽  
Cyclin D ◽  
Inhibition Of Proliferation ◽  
Cycle Arrest ◽  
Signal Specificity

Activated Raf has been linked to such opposing cellular responses as the induction of DNA synthesis and the inhibition of proliferation. However, it remains unclear how such a switch in signal specificity is regulated. We have addressed this question with a regulatable Raf-androgen receptor fusion protein in murine fibroblasts. We show that Raf can cause a G1-specific cell cycle arrest through induction of p21Cip1. This in turn leads to inhibition of cyclin D- and cyclin E-dependent kinases and an accumulation of hypophosphorylated Rb. Importantly, this behavior can be observed only in response to a strong Raf signal. In contrast, moderate Raf activity induces DNA synthesis and is sufficient to induce cyclin D expression. Therefore, Raf signal specificity can be determined by modulation of signal strength presumably through the induction of distinct protein expression patterns. Similar to induction of Raf, a strong induction of activated Ras via a tetracycline-dependent promoter also causes inhibition of proliferation and p21Cip1 induction at high expression levels. Thus, p21Cip1 plays a key role in determining cellular responses to Ras and Raf signalling. As predicted by this finding we show that Ras and loss of p21 cooperate to confer a proliferative advantage to mouse embryo fibroblasts.

scholarly journals PPARγ Activation Inhibits Growth and Survival of Human Endometriotic Cells by Suppressing Estrogen Biosynthesis and PGE2 Signaling.

Endocrinology ◽  
2013 ◽  
Vol 154 (12) ◽  
pp. 4803-4813 ◽  
Author(s):  
Dan I. Lebovic ◽  
Shahryar K. Kavoussi ◽  
JeHoon Lee ◽  
Sakhila K. Banu ◽  
Joe A. Arosh
Keyword(s):  
Cell Cycle ◽  
Stromal Cells ◽  
Cell Cycle Regulation ◽  
Chronic Inflammatory Disease ◽  
Reproductive Age ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Growth And Survival ◽  
Cycle Regulation ◽  
Estrogen Biosynthesis

Endometriosis is a chronic inflammatory disease of reproductive age women leading to chronic pelvic pain and infertility. Current antiestrogen therapies are temporizing measures, and endometriosis often recurs. Potential nonestrogenic or nonsteroidal targets are needed for treating endometriosis. Peroxisome proliferator-activated receptor (PPAR)γ, a nuclear receptor, is activated by thiazolidinediones (TZDs). In experimental endometriosis, TZDs inhibit growth of endometriosis. Clinical data suggest potential use of TZDs for treating pain and fertility concurrently in endometriosis patients. Study objectives were to 1) determine the effects of PPARγ action on growth and survival of human endometriotic epithelial and stromal cells and 2) identify the underlying molecular links between PPARγ activation and cell cycle regulation, apoptosis, estrogen biosynthesis, and prostaglandin E2 biosynthesis and signaling in human endometriotic epithelial and stromal cells. Results indicate that activation of PPARγ by TZD ciglitazone 1) inhibits growth of endometriotic epithelial cells 12Z up to 35% and growth of endometriotic stromal cells 22B up to 70% through altered cell cycle regulation and intrinsic apoptosis, 2) decreases expression of PGE2 receptors (EP)2 and EP4 mRNAs in 12Z and 22B cells, and 3) inhibits expression and function of P450 aromatase mRNA and protein and estrone production in 12Z and 22B cells through EP2 and EP4 in a stromal-epithelial cell-specific manner. Collectively, these results indicate that PGE2 receptors EP2 and EP4 mediate actions of PPARγ by incorporating multiple cell signaling pathways. Activation of PPARγ combined with inhibition of EP2 and EP4 may emerge as novel nonsteroidal therapeutic targets for endometriosis-associated pain and infertility, if clinically proven safe and efficacious.

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