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1.
Cyclic amp-induced morphological transformation of cells infected by temperature-sensitive mouse sarcoma virus: Expression of transformation-associated markers
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Normal rat kidney (NRK) cells infected with a temperature-sensitive (ts) mutant of mouse sarcoma virus (NRK [MSV-1b]) express the transformed phenotype when grown under permissive conditions, but acquire the normal phenotype when grown under restrictive conditions. Addition of 3', 5' cyclic adenosine monophosphate (cAMP) to NRK (MSV-1b) cells grown at the restrictive temperature results in morphological transformation. To determine whether other markers associated with the transformed phenotype were coordinately expressed after cAMP exposure, concanavalin A (Con A) agglutinability, hexose transport rate, and incorporation of radioactively labeled fucose into fucolipid III and fucolipid IV (FL III and FL IV ) of the cells were examined. NRK cells transformed by wild-type MSV or NRK(MSV- 1b) grown under permissive conditions were agglutinated by low concentrations of Con A and exhibited relatively high maximal agglutination levels which were specifically inhibited by α-methyl-D-mannoside. In contrast, NRK (MSV-1b) cells grown under restrictive conditions were weakly agglutinated by Con A and exhibited reduced maximal agglutination levels, similar to uninfected NRK cells. Treatment of NRK (MSV-1b) cells at the restrictive temperature with cAMP resulted in morphological transformation and a change in the pattern of incorporation of labeled fucose inot FL III and FL IV to one comparable to that of NRK (MSV-1b) cells at the permissive temperature or to NRK cells transformed by wild-type MSV. In contrast, cAMP treatment resulted in no increase in Con A agglutinability or 2 deoxy-D- [(3)H]glucose transport relative to mock treated cultures. The results demonstrate that cAMP-induced morphological transformation and altered fucolipid composition of NRK (MSV-1b) cells are not correlated with alterations in hexose transport rate or Con A agglutinability. 相似文献
2.
K D Somers 《In vitro》1980,16(10):851-858
Normal rat kidney cells infected with a cold-sensitive mutant of mouse sarcoma virus [NRK(MSV-lb)] morphologically transform when exposed to adenosine 3':5' cyclic monophosphate (cAMP) at the restrictive temperature. The cAMP-induced morphological changes occur rapidly and are reversible. Agents capable of elevating endogenous levels of cAMP [prostaglandin E1 (PGE1) and cholera toxin (CT)] induced morphological transformation of NRK(MSV-lb) cells at the restrictive temperature that was concentration dependent, potentiated by cAMP phosphodiesterase inhibitors, and not prevented by inhibitors of DNA, RNA, and protein synthesis. Prostaglandin E1 stimulated a transient increase in the intracellular level of cAMP with a concomitant morphological transformation and reversion of cells as cAMP levels decline. The maximum increase is reached by 10 min, followed by a decline to near basal level by 80 min. In contrast, incubation of cells with CT resulted in irreversible morphological transformation and increased levels of cAMP first detectable by 1 hr with maximum levels reached by 24 hr. Heated CT (100 degrees C, 20 min) was without effect. Addition of CT to reverted PGE1-treated cells resulted in morphological transformation suggesting the existence of discrete receptors in NRK(MSV-lb) cells. 相似文献
3.
Robert O. Hussa Michaei T. Story Roland A. Pattillo Robert G. Kemp 《In vitro cellular & developmental biology. Plant》1977,13(7):443-449
Summary The secretion of human chorionic gonadotropin (hCG) is stimulated by addition of N6, O2′-dibutyryl cyclic 3′:5′-AMP (dbcAMP) or theophylline to normal term placenta and human malignant trophoblast cells in vitro.
To understand better the specificity of this process. malignant trophoblast cultures were incubated with 3′:5′-cyclic AMP
(cAMP) derivatives, prostaglandins and other agents for 1 to 3 days, and the secretion of radioimmuno-assayable hCG was measured.
Whereas dbcAMP was the most potent agent in stimulating secretio of hCG, the N6- and O2′-monobutyryl derivatives of cAMP and phosphodiesterase inhibitors (theophylline, papaverine, 3-isobutyl-1-methylxanthine)
also increased the secretion of the hormone. A slight increase in hCG secretion was observed following addition of adenine.
By contrast, butyrate, cAMP, cyclic 3′:5′-GMP (cGMP), dbcBMP, 5′-AMP, adenosine, L-epinephrine and prostaglandins E1, E2, F1α and F2α were ineffective. Particulate fractions from sonicates of malignant trophoblast cultures contained adenylate cyclase activity
which was stimulated more than 10-fold by NaF, but not by either catecholamines or prostaglandins. The relatively specific
stimulation of hCG secretion suggested that a regulatory process involving cAMP may have physiological significance in the
trophoblast.
This investigation was supported by Grant Nos. CA14232 and CA16539 awarded by the National Cancer Institute, DHEW. 相似文献
4.
E Pick 《Cellular immunology》1977,32(2):329-339
Intracellular levels of cyclic 3′,5′-adenosine monophosphate (cAMP) in purified guinea pig peritoneal macrophages were elevated following incubation with the adenylate cyclase stimulators prostaglandins E1 and E2 (PGE1, PGE2), isoproterenol, and cholera toxin. Exposure of macrophages to antigen-stimulated lymphocyte culture supernatants, containing migration inhibitory factor (MIF), resulted in a moderate but consistent decrease in the cAMP level, which was best expressed after 1–2 hr of incubation. Incubation of macrophages with MIF-containing supernatants or partially purified MIF for 1–2 hr resulted in reduced cAMP accumulation in response to PGE1, PGE2, isoproterenol, and cholera toxin (nonspecific refractoriness). These findings indicate that MIF-induced inhibition of macrophage migration is not due to an increase in the cellular level of cAMP and that the reduction in cAMP concentration, caused by MIF, is probably a secondary phenomenon unrelated to the inhibition of cellular motility. 相似文献
5.
J. I. Kreisberg P. Y. Patel M. A. Venkatachalam G. Taylor 《In vitro cellular & developmental biology. Plant》1986,22(7):392-396
Summary Cultured glomerular epithelial cells form a continuous monolayer of polyhedral-shaped cells. PGE2 (1 μg/ml) in the presence of the phosphodiesterase inhibitor isobutylmethylxanthine (MIX) markedly raises intracellular and
medium cyclic AMP (cAMP) levels at 20 min (intracellular: MIX alone, 112 ± 6.6 pmol cAMP/mg protein, MIX plus PGE2, 2252±63 pmol cAMP/mg protein; medium: MIX, 20.6±2.1 pmol cAMP/mg protein; MIX plus PGE2, 117±3.8 pmol cAMP/mg protein). By 2 h, when cellular and medium cAMP levels were still elevated, the cells underwent a change
in shape that was similar to dome formation (15 to 20% of the monolayer changing shape). Derivatives of cAMP [i. e. dibutyryl
and 8-(4-chlorophenylthio)-cAMP], when added to the incubation medium also caused shape change in glomerular epithelial cells
at 2 h; cAMP itself did not. The formation of domes has been used as a morphological indicator of the vertorial transport
of salt and water in other cultured epithelial cells.
This work was supported by grant AM 29787 from the National Institutes of Health, Bethesda, MD. 相似文献
6.
T.A. Fitz E.J. Mock M.H. Mayan G.D. Niswender 《Prostaglandins & other lipid mediators》1984,28(1):127-138
Purified preparations of ovine large luteal cells were utilized in a series of experiments to test the effects of prostaglandins (PG) E2 abd F2α on cell morphology, viability and secretion of progesterone. Luteal cells were allowed to attach to culture dishes overnight before experiments. In the first series of experiments incubation of large steroidogenic cells with PGF2α for 6 hr resulted in morphological changes including a retraction of the cell cytoplasm and apparent extrusion of cytoplasmic components which became more pronounced after 12 hr. In a second series of experiments, PGF2α decreased and PGE2 increased progesterone accumulation in media after 6 hr when media were not replaced during the incubation period, while progesterone accumulation was not different than that observed in control dishes when both prostaglandins were present. Hourly replacement of the media negated the inhibitory effects of PGF2α but had no effect on the stimulated secretion of progesterone induced by PGE2. Finally, in incubations without media replacement, PGF2α induced a dose-dependent decrease in progesterone accumulation while PGE2 elicited a biphasic response with progesterone secretion increasing from 0.1 ng/ml to maximal levels at 10 ng/ml followed by a dose-dependent decrease at 100 and 1000 ng/ml. These data are compatible with the hypotheses that: 1) luteolysis is initiated, at least in part, by an action of PGF2α on large luteal cells; and 2) the embryonic signal from the pregnant uterus which rescues the ovine corpus luteum may be PGE2. 相似文献
7.
Takahiko Fukushige Makoto Nagoshi Yoichi Hachitanda Takaki Ueno Yoshio Zaizen Sachiyo Suita Masazumi Tsuneyoshi Yasuhiko Kaneko Akira Nakagawara 《Virchows Archiv. B, Cell pathology including molecular pathology》1992,62(1):159-166
A new human cell line, termedMuraoka, has been established from the recurrent tumor of a case of congenital primitive neuroectodermal tumor (PNET) arising at
the temporofacial region of a male infant. The microscopic findings of this cell line were epithelioid, and the xenografted
tumor in a nude mouse consisted of the malignant epithelioid cells. Immunohistochemically, the cells were positive for neuron-specific
enolase, S-100 protein, carcinoembryonic antigen, cytokeratin, epithelial membrane antigen, and glial fibrillary acidic protein.
These findings were quite smiliar to those of the epithelioid cells in the original tumor and of the xenografted tumor cells.
Neither chromosomal abnormalities nor N-myc amplification were observed. Morphological differentiation after treatment with
N6-2′-Odibutyryladenosine 3′:5′-cyclic monophosphate (Bt2cAMP), all-trans-retinoic acid (RA), prostaglandin E1 (PGE1, and 5-bromo-2′-deoxyuridine (BrdU) showed two different results. Bt2-cAMP and PGE1 induced neuronal differentiation with the extension of neurites, whereas RA and BrdU predominantly induced Schwannian differentiation
(flat cells). In these respects, the cell lineMuraoka seems to be useful for studying characteristics of PNET as well as for developing the new treatments against such tumors. 相似文献
8.
Expression of the Major Internal Viral Polypeptide in Cells Transformed by Wild-Type and Temperature-Sensitive Murine Sarcoma Virus
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Gad Spira Gordon R. Dreesman Matilda Benyesh-Melnick Saul Kit Kenneth D. Somers 《Journal of virology》1974,14(5):1245-1252
Phenotypic expression of the murine intraspecies and interspecies antigenic determinants of the major type C viral structural 30,000-dalton polypeptide, p30, was measured by radioimmunoassay inhibition in cell lines from different species. Uninfected normal rat kidney (NRK) cells did not contain detectable levels of murine intraspecies and interspecies p30 antigen, whereas rat cells transformed by and producing murine sarcoma virus (MSV)-Moloney leukemia virus (M-MSV-MuLV) contained high levels of both murine intraspecies and interspecies p30 antigen. Significant amounts of murine intraspecies and interspecies p30 antigen were detected in wild-type MSV-transformed nonproducer NRK cells. The control of p30 antigen expression was examined in temperature-sensitive MSV-transformed nonproducer cells [NRK(MSV-1b)] which are cold sensitive for maintenance of the transformed phenotype. Both murine intraspecies and interspecies p30 antigens were detected in NRK(MSV-1b) cells when grown at the permissive (39 C) or nonpermissive (33 C) temperature, suggesting that p30 antigen expression is not correlated with maintenance of the transformed phenotype. The results demonstrate that previously undetectable p30 antigens are expressed in MSV-transformed nonproducer NRK cells, and suggest that the expression of p30 antigen may be a useful marker for viral gene expression in mammalian cells. 相似文献
9.
Summary Dexamethasone, R020-1724 and prostaglandin E1 all induced morphological alterations and increased the glial specific enzyme 2′,3′-cyclic nucleotide 3′-phosphohydrolase
(CNP) in rat C6 glioma cells in culture. Morphological alterations consisted mainly in the development of astrocytelike changes.
Increases in dexamethasone-induced CNP activity was time dependent. Dexamethasone reduced cell growth rate, depending on the
concentration employed.
This paper is supported in part by N.I.M.H. Research Grant AA02372. Dr. S. Kamath participated initially in this study. 相似文献
10.
THE DEPRESSION OF PHAGOCYTOSIS BY EXOGENOUS CYCLIC NUCLEOTIDES, PROSTAGLANDINS, AND THEOPHYLLINE 总被引:10,自引:1,他引:9
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The effects of agents that elevate intracellular cyclic adenosine 3',5'-monophosphate (cAMP) have been studied with respect to phagocytosis by guinea pig polymorphonuclear leukocytes. The investigation depends upon the use of a precise method for following ingestion. Theophylline, dibutyryl cAMP, and prostaglandins inhibited the phagocytosis of starch particles. The inhibitions caused by prostaglandins E1, E2, and F2α (PGE1, PGE2, and PGF2α) were synergistic with that due to theophylline. Inhibition by PGA1 and PGA2 was not. At equal concentrations the order of increasing inhibition of phagocytosis (assayed at 10 min) by the prostaglandins was PGE1 < PGF2α < PGE2 < PGA1 = PGA2. Our results are consistent with the hypothesis that increased intracellular levels of cAMP impair the phagocyte's ability to ingest particles. The mechanism of the inhibition has not been defined. The increment in oxidation of [1-14C]glucose to 14CO2 that normally accompanies phagocytosis was found to be depressed in the presence of PGE1 or theophylline, together or individually as expected from the inhibition of phagocytosis. Paradoxically, oxygen consumption although depressed by theophylline or PGE1 plus theophylline, was stimulated by PGE1 alone. 相似文献
11.
Ph.D. David I. Wilkinson Ph.D. Elaine K. Orenberg 《Prostaglandins & other lipid mediators》1979,17(3):419-429
Guinea pig ear epidermal cells (keratinocytes) were established in primary cultures using trypsin, and treated in their proliferative phase of growth with prostaglandins E1, D1, F1α, E2, D2, or F2α. This phase is induced by the addition of retinoic acid during cell plating. Intracellular content of cAMP and cGMP was measured by radioimmunoassay at various times after treatment.Maximum stimulation of cAMP levels was observed with PGD2, smaller increases with PGE2 and relatively transient rises with PGF2α which were of low significance, but confirm earlier data. Similar results were observed with PGD1, PGE1, and PGF1α with smaller increases. The effects of D and E PGs were biphasic. Significant increases in cGMP were immediately observed with PGD2 and PGE2. With PGF2α, maximum cGMP levels were noted after some delay.All PGs tested showed some effect in elevating cyclic nucleotides in keratinocytes. The most striking result was the increase in cAMP on PGD2 treatment. 相似文献
12.
Charles J. Malemud Teresa M. Mills Robert S. Papay 《Prostaglandins & other lipid mediators》1986,32(4)
Recent experimental studies indicated that prostaglandin E2 (PGE2) is the most abundant prostanoid synthesized by rabbit articular chondrocytes. Exogenous PGE2 stimulates cyclic AMP (cAMP) synthesis in these cells. Analogues of cAMP and forskolin have now been shown to suppress the biosynthesis of PGE2 in the presence of serum in a time-dependent manner. The most abundant prostanoid, PGE2 was most markedly affected. PGF2α was unaffected. These results indicated that intracellular accumulation of cAMP in chondrocytes and relative resistance of cAMP to phosphodiesterases control prostanoid synthesis in a negative feedback loop. 相似文献
13.
Preparations of small and large steroidogenic cells from enzymatically dispersed ovine corpora lutea were utilized to study the effects of luteinizing hormone (LH) and prostaglandins (PG) E1, E2 and I2. Cells were allowed to attach to culture dishes overnight and were incubated with either LH (100 ng/ml), PGE2, PGE2, or PGI2 (250 ng/ml each). The secretion of progesterone by large cells was stimulated by all prostaglandins tested (P < 0.05) while the moderate stimulation observed after LH treatment was attributable to contamination of the large cell population with small cells. Prostaglandins E1 and E2 had no effect on progesterone secretion by small cells, while LH was stimulatory at all times (0.5 to 4 hr) and PGI2 was stimulatory by 4 hr. Additional studies were conducted to determine if the effects of PGE2 upon steroidogenesis in large cells were correlated with stimulated activity of adenylate cyclase. In both plated and suspended cells PGE2 caused an increase (P < 0.05) in the rate of progesterone secretion but had no effect upon the activity of adenylate cyclase or cAMP concentrations within cells or in the incubation media. Exposure of luteal cells to forskolin, a nonhormonal stimulator of adenylate cyclase, resulted in marked increases in all parameters of cyclase activity but had no effect on progesterone secretion. These data suggest that the actions of prostaglandins E1, E2 and I2 are directed primarily toward the large cells of the ovine corpus luteum and cast doubt upon the role of adenylate cyclase as the sole intermediary in regulation of progesterone secretion in this cell type. 相似文献
14.
Preparations of small and large steroidogenic cells from enzymatically dispersed ovine corpora lutea were utilized to study the
effects of luteinizing hormone (LH) and prostaglandins (PG) E1, E2 and I2. Cells were allowed to attach to culture dishes overnight and were incubated with either LH (100 ng/ml), PGE2, PGE2, or PGI2 (250 ng/ml each). The secretion of progesterone by large cells was stimulated by all prostaglandins tested (P < 0.05) while the moderate stimulation observed after LH treatment was attributable to contamination of the large cell population with small cells. Prostaglandins E1 and E2 had no effect on progesterone secretion by small cells, while LH was stimulatory at all times (0.5 to 4 hr) and PGI2 was stimulatory by 4 hr. Additional studies were conducted to determine if the effects of PGE2 upon steroidogenesis in large cells were correlated with stimulated activity of adenylate cyclase. In both plated and suspended cells PGE2 caused an increase (P < 0.05) in the rate of progesterone secretion but had no effect upon the activity of adenylate cyclase or cAMP concentrations within cells or in the incubation media. Exposure of luteal cells to forskolin, a nonhormonal stimulator of adenylate cyclase, resulted in marked increases in all parameters of cyclase activity but had no effect on progesterone secretion. These data suggest that the actions of prostaglandins E1, E2 and I2 are directed primarily toward the large cells of the ovine corpus luteum and cast doubt upon the role of adenylate cyclase as the sole intermediary in regulation of progesterone secretion in this cell type. 相似文献
15.
Kedar N. Prasad Sanjay Kumar Erika Carvalho Judith Edwards-Prasad Rita Kumar Francisco G. La Rosa Birte B. Larsen David Ann 《In vitro cellular & developmental biology. Animal》1995,31(10):767-772
Summary This study reports the isolation and characterization of a rat nontumorigenic parotid acinar cell clone (2RSG), a human nontumorigenic
parotid acinar cell clone (2HPC8), and a human tumorigenic acinar clone (2HP1G). The levels ofα-amylase mRNAs detected when usingα-amylase cDNA of 1176 and 702 bp for hybridization were higher in 2RSG and 2HPC8 cells than their respective whole parotid
glands. The level of these mRNAs decreased in 2HP1G cells. In contrast toα-amylase mRNAs levels, theα-amylase activity in cultured acinar cells was extremely low in comparison to whole glands, irrespective of species or cell
status. The levels of proline-rich protein (PRP) mRNA and parotid secretory protein (PSP) mRNA detected when using PRP cDNA
of 600 bp and PSP cDNA of 805 bp for hybridization were higher in 2RSG cells than those in rat parotid glands; the reverse
was observed in 2HPC8 cells and human parotid glands. The levels of PRP mRNA and PSP mRNA in 2HPC8 and 2HP1G acinar cells were similar. The level of mRNA was not detectable in murine neuroblastoma cells (NBP2) using the sameα-amylase cDNA, PRP cDNA and PSP cDNA for hybridization. The PSP level in rat parotid gland was lower than that found in 2RSG
cells; the reverse was observed in 2HPC8 cells and human parotid glands. The level of PSP in 2HP1G cells was higher than that found in 2HPC8 cells. Isoproterenol increased the cAMP level in 2RSG, 2HPC8, and 2HP1G clones, being most effective in 2RSG cells, and least effective in 2HPG cells. Prostaglandin E1 (PGE1) also increased cAMP level, being most effective in 2HPC8 cells and ineffective in 2HP1G cells, suggesting that the PGE1 receptor-linked adenylate cyclase becomes inactive upon transformation. These results suggest that the three clonal acinar
cells from rat and human parotid glands reported here can be useful in comparative studies on regulation of growth, differentiation,
and transformation. 相似文献
16.
Concentrations of cyclic AMP (cAMP) were increased in isolated renal cortical tubules from hamsters by both parathyroid hormone (PTH) and prostaglandin E1 (PGE1) with maximal effects of PGE1 being 6–8 fold greater than those of PTH during a 10 min period. However, cAMP concentrations in cells treated with 1-methyl-3-isobutylxanthine (MIX) were increased with maximal concentrations of either hormone to the same degree. Similar effects of both hormones were observed on adenylate cyclase activity in renal homogenates. Simultaneous addition of hormones produced changes in both cAMP concentrations in intact tubules as well as adenylate cyclase activity of homogenates which were not completely additive. Degradation of cAMP, estimated in intact tubules as the difference in cAMP levels in the presence and absence of MIX, was increased by both hormones, however, changes were 2–3 fold greater in tubules exposed to PTH than to PGE1. Neither hormone directly altered cAMP phosphodiesterase (PDE) activity in either 30,000 x g supernatant or pellets from renal cortical homogenates.The results suggest that both hormones increase the production of cAMP in renal cortical tubules and may share a common target cell type in this response. Degradation of cAMP, however, is differentially effected by the two hormones, probably reflecting differences exerted on intracellular mechanisms regulating the enzymatic hydrolysis of cAMP. 相似文献
17.
Chlapowski F. J. Ray K. P. Butcher R. W. 《In vitro cellular & developmental biology. Plant》1978,14(11):924-934
Summary Long-term (48-hr) incubations of either the fibroblast strain WI-48 or its SV40-transformed counterpart, WI-38-VA13-2RA, in
growth medium containing 1 μm prostaglandin E1 (PGE1) resulted in a sustained production and release of cyclic AMP from the cells into the medium. Despite the steady production,
intracellular levels of the nucleotide decreased, reaching steady-state values within 4 hr of the initial exposure to PGE1. These values were maintained for the remainder of the 48-hr experimental period. The steadystate levels of intracellular
cyclic AMP were higher than those observed in unstimulated cells, and cyclic AMP-dependent protein phosphokinase was in a
highly activated state as compared to controls. Under these conditions little change in the growth or morphology of either
the normal or transformed cells was observed. In contrast, inhibition of growth, apparent cell death, and unusual morphological
changes were observed in both normal and transformed cells when high concentrations of either PGE1 (10 μm) or the phosphodiesterase inhibitor 1-methyl, 3-isobutylxanthine (0.5mm to 2mm) were used, which was indicative of toxic effects of the drugs. It was concluded that cyclic AMP-mediated activation of protein
phosphokinase does not completely inhibit growth in WI-38 cells or restore normal growth and morphology to the SV40-transformed
cells.
This work was supported by Grants AM 13904 and CA 21612 from the National Institutes of Health, Department of Health, Education
and Welfare. 相似文献
18.
Gunnar Selstam Jan Liljekvist Sten Rosberg Lena Grönquist Torsten Perklev Kurt Ahrén 《Prostaglandins & other lipid mediators》1974,6(4):303-311
Isolated whole ovaries from 23–24 day-old rats were studied in order to compare the effects of prostaglandin E1 (PGE1) and luteinizing hormone (LH) on ovarian cyclic adenosine 3′,5′-monophosphate (cAMP) production. Both substances produced a dose-dependent accumulation of cAMP in the ovarian tissue as well as in the incubation medium. The release of cAMP to the incubation medium was considerable after long periods of incubation (60–120 min). Time-relationships for LH- and PGE1-effects were different. Maximal cAMP content in the tissue after addition of PGE1 was seen already after 5–15 min of incubation whereas LH gave a maximal response after around 60 min. Accumulation of cAMP in the medium was approximately linear with time for both LH and PGE1. Addition of theophylline potentiated the action of PGE1 and LH but did not change the time-courses of the effects. It is concluded that the accumulation of cAMP in the medium should be considered in studies with various in vitro types of ovarian preparations. It is also pointed out that the different time-courses of the LH- and PGE1-effects make the interpretation of additivity experiments difficult. 相似文献
19.
Leonard A. Cohen Rashida A. Karmali 《In vitro cellular & developmental biology. Plant》1984,20(2):119-126
Summary The production and release of prostaglandins (PGs) into the growth medium by established cultures of neoplastic, mammary epithelial
cells derived from (a)N-nitrosomethyl-urea (NMU)-induced and (b) 7,12-dimethylbenz(a) anthracene (DMBA)-induced mammary tumors, was assessed using radioimmunoassay techniques.
Prostaglandin production was determined, to a considerable extent, by in vitro conditions and the tumor line analyzed. In
medium supplemented with bovine calf serum (10%), NMU cells synthesized and released nanogram quantities of PGF2, PGE1, and PGF2α (6.7, 4.7, and 1.7 ng/106 cells per 48 h, respectively). Concentrations of the two stable protanoid metabolites, 6-keto-PGF1α and TXB2, were indistinguishable from controls. In cells derived from the DMBA-induced tumor (RBA cells), no net production of immunoreactive
PGs was detected. In contrast, in media supplemented with fetal bovine serum (10%), both RBA and NMU cells synthesized and
released nanogram quantities of PGE2 (1 and 4 ng/106 cells per 48 h, respectively).
PGE2 production by both NMU and RBA cells was inhibited by ibuprofen, an inhibitor of cyclooxygenase (EC 1. 14. 99.1). The pattern of PG inhibition by ibuprofen differed in the two cell lines. In NMU cells, a linear dose-response inhibitory
pattern was discernable, whereas in RBA cells a biphasic pattern was observed; PGE2 levels incresed at low concentration of ibuprofen and then decreased at higher concentration. At 100 μg/ml ibuprofen, PG
synthesis and release was inhibited by 90 and 100% and cell growth by 64 and 66% in NMU and RBA cells, respecively. There
was no obvinous dse-response relationship between ibuprofen concentration and cell growth inhibition in either cell line.
These results underline the importance of the serum component of growth medium when analyzing PG production in vitro and suggest
that the epithelial cell components of experimental mammary tumors are capable of producing physiogically relevant amounts
of PGs.
This work was supported by Grant CA 29602 from the National Cancer Institute, Bethesda, MD, and Grant PDT-208 from the American
Cancer Society. 相似文献
20.
Jia-Huey Yu Herbert Wells B. Moghadam William J. Ryan Jr. 《Prostaglandins & other lipid mediators》1979,17(1):61-69
PGE2 produced a marked and dose-related increase in cAMP content of cultured bone cells and in the release of cAMP into the incubation medium. The amount of cAMP released from the cells by PGE2 was proportional to the cellular concentration, and was dependent upon the time of incubation with PGE2. The cAMP levels released into the media increased slowly at a linear rate during a 60 min treatment with PGE2. This release was blocked by theophylline, probenecid, ouabain and dinitrophenol, suggesting that the release of cAMP was not a simple diffusive process and required energy. SC-19220 reduced the formation of cAMP more than the release, suggesting that the formation and the release may arise from separate events. Inability of D600 to inhibit PGE2-induced release of cAMP indicates that the release does not require calcium. 相似文献