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1.
Continuous multiplication of rabbit tracheal epithelial cells in a defined,hormone-supplemented medium 总被引:16,自引:0,他引:16
Summary An improved Ham’s F12 nutrient medium supplemented with epidermal growth factor (EGF), insulin (INS), and transferrin (TF)
was developed for continuous proliferation and clonal growth of primary rabbit tracheal epithelial (TE) cells in culture.
The addition of small quantities of fetal bovine serum (FBS) (0.01 to 0.1%) to cultures had little measurable stimulation
on TE cell growth and plating efficiency. However, serum levels higher than 0.1% inhibited cell growth and also masked the
growth stimulating activities of EGF and INS despite an increase in cell attachment. Under this defined, hormone-supplemented
medium, and in the presence of a trace amount of serum (0.01%), 10 to 20% of the protease-dissociated TE cells attached to
the culture dish followed by at least four population doublings during 7 to 10 d of culture. Clonal growth occurred at a seeding
density of 17 cells/cm2 with a plating efficiency of 6 to 8%. Confluent primary cultures could be passaged two to four times by treatment with a
0.1% trypsin-1 mM EDTA solution and a total of 10 to 30 population doublings of in vitro life span were obtained. The epithelial nature of
cultured cells was confirmed by indirect immunofluorescent staining with antikeratin antibody as well as by transmission electron
microscopy. This study shows that using this improved hormone-supplemented medium, rabbit TE cells can be maintained in culture
for extended periods of time without the aid of a fibroblast feeder layer or explant tissue. This system could be useful for
the study of cell differentiation of tracheal epithelium. 相似文献
2.
I Bertoncello T R Bradley W A Chamley G S Hodgson 《Journal of cellular physiology》1982,113(2):224-230
Normal, primary explanted, bovine granulosa cells grow reproducibly in agar culture as anchorage-independent clones. Epidermal growth factor (EGF) and rat erythrocytes are effective stimulators of colony formation, and when both are added to the culture medium at optimal concentrations, there is an enhancement of colony numbers and colony size, indicative of an independent, and operationally additive, mode of action for the two factors. The ability of cells propagated from agar clones to secrete progesterone, and to augment progesterone secretion 4-fold in the presence of 1 mM dbcAMP is proof that colonies originate from and are composed of functional granulosa cells. Maximal colony numbers are present at day 10 of incubation, and colony forming cells undergo self-renewal as assessed by the ability of cells from primary colonies to reclone in agar. Absolute cloning efficiency, however, is dependent on a number of factors. Inherent variability exists in cloning efficiency of granulosa cells from individual follicles. Quantitative and qualitative clonal growth was improved at an osmolality of less than 300 mOsm when compared with higher osmolalities. Cl-1 medium and the alpha modification of Eagle's medium were equally effective in supporting agar clonogenic growth, whereas both Ham's F12 and NCTC 135 media exhibited poor clonogenic growth supporting properties. The substitution of agarose for agar did not affect colony numbers but colonies grown in the presence of agarose tended to be smaller and more uniform in size. 相似文献
3.
《Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism》1992,1123(1):65-75
The role in cell multiplication and maturation of several factors present in the late fetal lung was explored on isolated fetal rat pulmonary fibroblasts and alveolar epithelial type II cells cultivated in serum-free medium. The low degree of reciprocal contamination of each cell population was assessed by immunocytochemistry. Epidermal Growth Factor (EGF) stimulated thymidine incorporation and DNA accumulation in both cell types. In type II cells, it increased labeled-choline incorporation into surfactant phosphatidylcholine (PC), consistently with previous data obtained with lung explant cultures, but not into non-surfactant PC. Insulin-like growth factor (IGF)-I slightly stimulated DNA accumulation in fibroblasts although it did not significantly stimulate thymidine incorporation, contrary to IGF-II which presented a dose-dependent stimulating activity of thymidine incorporation. Neither IGF-I nor IGF-II stimulated type II cell growth. IGFs thus appear to primarily control the growth of lung mesenchyme. In type II cells, they stimulated the most non-surfactant PC biosynthesis. Gastrin releasing peptide (GRP) which was recently reported to promote fetal lung growth in vivo and to stimulate surfactant biosynthesis in lung organ culture revealed as a growth factor for type II cells only, at concentrations below 10 −9 M. At concentration 10 −8 M, although it did not affect DNA synthesis, GRP tended to increase surfactant and non-surfactant-PC biosynthesis. Retinoic acid inhibited thymidine incorporation into type II cells on a dose-dependent manner but nevertheless enhanced surfactant-PC biosynthesis to a similar extent as EGF. It is suggested that retinoic acid may represent a differentiation or maturation factor for the alveolar epithelium. 相似文献
4.
Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) induce proliferation of neural precursor cells from several central nervous system regions in vitro. We have previously described two neural precursor cell populations from 13.5 days postcoitium (dpc) mesencephalon, one forming colonies in response to EGF, present in the ventral mesencephalon, and other forming colonies in response to EGF + bFGF, mainly present in the dorsal mesencephalon. In the present work, we show that 13.5 dpc dorsal mesencephalic cells required bFGF only for 1 h to form colonies in response to EGF alone, indicating that these two growth factors act in sequence rather than simultaneously. Absence of bFGF at the beginning of the culture gave rise to very few colonies, even after the addition of EGF + bFGF, suggesting that cells responsive to bFGF were very labile in the primary culture condition. This result is in contrast with cells pretreated with bFGF, which could survive for up to 5 days in the absence of bFGF or EGF, and then were capable of efficiently forming colonies in response to EGF. Basic FGF was also able to support survival of EGF‐responsive neural precursors from both ventral and dorsal mesencephalon. The population requiring bFGF to form colonies in response to EGF was identified at different developmental stages (11.5–15.5 dpc), with higher contribution to the total number of neural precursors cells detected (EGF‐responsive plus bFGF‐responsive) at early stages and in the dorsal region. We show that the differentiation effect of bFGF resulted in the appearance of the mRNA coding for the EGF receptor. Our data suggest that bFGF‐responsive neural precursors are the source of EGF‐responsive neural precursors. © 1999 John Wiley & Sons, Inc. J Neurobiol 40: 14–27, 1999 相似文献
5.
David R. Clemmons 《Journal of cellular physiology》1984,121(2):425-430
Multiple growth factors that circulate in plasma have been shown to stimulate cellular growth in vitro. The plasma growth factors appear to stimulate DNA synthesis in cultured fibroblasts only after prior exposure of cell growth factors derived from circulating cell types, such as platelets and macrophages. The purpose of these studies was to investigate the role of the plasma growth factors in stimulating smooth muscle cell replication following exposure to platelet-derived growth factor (PDGF). Following transient exposure to PDGF, insulin stimulated smooth muscle cell replication but only when supraphysiologic concentrations were used (i.e., greater than 1.0 μg/ml). Somatomedin-C (Sm-C), in contrast, was found to stimulate a 320% increase in [3H]thymidine incorporation when concentrations that are present in extracellular fluids were used (i.e., 0.5–10 ng/ml). Epidermal growth factor (EGF), an important mitogen for multiple cell types, caused a 70% increase in [3H]thymidine incorporation when added to quiescent cells following PDGF exposure, and EGF caused a substantial increase in the absolute level of [3H]thymidine incorporation when coincubated with Sm-C. When EGF (1 ng/ml) was incubated simultaneously with concentrations of Sm-C between 1 and 10 ng/ml plus Sm-C-deficient plasma, maximal [3H]thymidine incorporation was 2.1-fold greater in the presence of EGF. In contrast, insulin (20 ng/ml), when coincubated with Sm-C under similar conditions, had no enhancing effect on the cellular response to Sm-C. None of the plasma factors tested was an effective stimultant of replication when incubated either in serum-free medium or in the presence of Sm-C-deficient plasma without prior PDGF exposure. Hydrocortisone was shown to inhibit smooth muscle cell replication in concentrations between 10?7 and 10?5M. In summary, multiple plasma growth factors can stimulate the smooth muscle cell replication, and Sm-C appears to be most effective of those tested. Insulin and EGF appear to work by different mechanisms; that is, EGF can facilitate the cellular response to Sm-C, whereas insulin is effective only at supraphysiologic concentrations at which it will directly bind to Sm-C receptors. 相似文献
6.
Viable protoplasts of Taxus yunnanensis were isolated from friable, light yellow callus. Protoplast yield was dependent on callus age, with a maximum from 20-day-old
callus. Protoplasts were induced to undergo sustained divisions and to form cell colonies when cultured in medium consisting
of B5 salts, KM vitamin and organic components, 0.45 M fructose, 3.0 mg l-1 2,4-dichlorophenoxyacetic acid and 0.1 mg l-1 kinetin. The planting density was 2.5–3.0×105 protoplasts per ml of culture medium. Cell-free extract from callus enhanced protoplast division and the highest plating
efficiency was about 7%. Protoplast-derived colonies showed significant variations in both growth and paclitaxel content.
A negative correlation existed between paclitaxel accumulation in colonies and their growth to some extent (r = −0.4485).
Among 70 colonies isolated from the heterogeneous protoplast cultures, colony TY-7 accumulated the highest paclitaxel content.
Paclitaxel accumulation in colony TY-7 was not great enough to produce paclitaxel for commercial purposes, however, success
in inducing colony formation from T. yunnanensis protoplasts provides an opportunity to obtain cell lines with high paclitaxel productivity from mutagenized protoplast cultures.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Neurotrophin channeling of neural progenitor cell differentiation 总被引:13,自引:0,他引:13
Benoit BO Savarese T Joly M Engstrom CM Pang L Reilly J Recht LD Ross AH Quesenberry PJ 《Journal of neurobiology》2001,46(4):265-280
The act of defining neuropoietic progenitor/stem cells is still in its early phases. Epidermal growth factor (EGF) stimulates extended proliferation of aggregates of subventricular striatal cells, taken from E15 mouse striatum, termed neurospheres in liquid culture. We have shown here and in previous work, using either immunohistochemistry or RT-PCR, that neurosphere cells express 13 cytokines (32 tested) and 20 cytokine receptors (28 tested), with 11 potential paracrine and nine potential autocrine loops. The neurotrophin receptors, Trk A, B, and C, were all expressed. Using a newly developed FACS single cell deposition technique, we evaluated the capacity of single EGF stimulated neurosphere cells to respond to the ligands for Trk A and B, nerve growth factor (NGF), and brain-derived neurotrophin factor (BDNF). Addition of NGF or BDNF to EGF for 14 days had no effect, but removal of EGF at day 14 with subsequent addition of BDNF or NGF resulted in an increase in neuronal and astroglial, but not oligodendrocyte, colony cells at 21 and 28 days of culture for BDNF, and of both cell types at 28 days for NGF. Tri-lineage colonies increased at day 21 with BDNF and at day 28 for both NGF and BDNF. Gross colony morphology also showed changes with neurotrophin addition, forming multiple individual cell balls or filamentous spreads. When EGF was withdrawn, a threshold effect was observed, with small, but not large, colonies ceasing growth. BDNF and NGF showed no effects on cell proliferation when compared to EGF controls, as determined by 5'-bromo-2-deoxyuridine (BrdU) incorporation and thus, they appear to affect differentiation of progenitor cells. These data indicate a sequential action of cytokines with EGF maintaining viability and proliferation and blocking differentiation. Removal of EGF is then permissive for the differentiating effects of BDNF and NGF. These data further indicate that the majority of EGF neurosphere clones have neurotrophin dependent tri-lineage potential. 相似文献
8.
A comparison of barley isolated microspore and anther culture and the influence of cell culture density 总被引:3,自引:0,他引:3
Comparisons were made between the efficiency of barley plant regeneration from anther culture (AC) and isolated microspore
culture (IMC) for the European winter cultivar `Igri' and the spring F1 Australian breeder's hybrid Amagi Nijo×WI2585. In both cases, IMC produced a higher number of green regenerant plantlets
per anther than AC. For `Igri' there was a 100- to 200-fold improvement and for Amagi Nijo×WI2585 there was a five- to ninefold
improvement of IMC over AC. To improve the consistency and reliability of the IMC method, we investigated several parameters,
including maltose concentration, subculture protocol, microspore plating density and colony plating density. Subculturing
during the liquid culture phase produced no significant improvement in the number of microspores developing into colonies.
The optimal concentration of maltose in the liquid induction medium was found to be 90 g l–1. Both microspore plating density and colony plating density were found to influence plant regeneration. Microspores produced
the highest numbers of colonies when plated at densities greater than 5×104 ml–1, and colonies produced optimal numbers of green plantlets when plated at 12.5–25 colonies/cm2.
Received: 23 March 1997 / Revision received: 29 May 1997 / Accepted: 25 June 1997 相似文献
9.
The binding of 125I-labeled epidermal growth factor (EGF) was studied in Panc-I human pancreatic carcinoma cells. At 37°C, binding was rapid and associated with marked endocytosis of the ligand. Bound EGF was sequentially converted to a number of more acidic species as follows: pI 4.55 to pI 4.2, to pI 4.35, to pI 4.0. EGF internalization and processing were blocked at 4°C. EGF did not alter cell growth when Panc-I cells were incubated in the presence of 2 to 10% serum. In contrast, when the serum concentration was lowered to 0.1%, EGF significantly enhanced cell replication after 6 days of culture. 相似文献
10.
Epidermal growth factor stimulates prostaglandin biosynthesis by canine kidney (MDCK) cells. 总被引:14,自引:0,他引:14
Serum and/or arachidonic acid stimulated prostaglandin production by dog kidney (MDCK) cells. Epidermal growth factor (EGF) at concentrations of 10?9 to 10?10 M stimulated the biosynthesis of prostaglandins by MDCK cells but not that by human fibroblasts (D-550), mouse fibroblasts (3T3), transformed mouse fibroblasts (MC5-5), and rabbit aorta endothelial cells (CLO). EGF also stimulated the release of radioactivity from MDCK cells radioactively labelled with [3H]arachidonic acid. 相似文献
11.
Basic fibroblast growth factor promotes epidermal growth factor responsiveness and survival of mesencephalic neural precursor cells. 总被引:28,自引:0,他引:28
Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) induce proliferation of neural precursor cells from several central nervous system regions in vitro. We have previously described two neural precursor cell populations from 13.5 days postcoitium (dpc) mesencephalon, one forming colonies in response to EGF, present in the ventral mesencephalon, and other forming colonies in response to EGF + bFGF, mainly present in the dorsal mesencephalon. In the present work, we show that 13.5 dpc dorsal mesencephalic cells required bFGF only for 1 h to form colonies in response to EGF alone, indicating that these two growth factors act in sequence rather than simultaneously. Absence of bFGF at the beginning of the culture gave rise to very few colonies, even after the addition of EGF + bFGF, suggesting that cells responsive to bFGF were very labile in the primary culture condition. This result is in contrast with cells pretreated with bFGF, which could survive for up to 5 days in the absence of bFGF or EGF, and then were capable of efficiently forming colonies in response to EGF. Basic FGF was also able to support survival of EGF-responsive neural precursors from both ventral and dorsal mesencephalon. The population requiring bFGF to form colonies in response to EGF was identified at different developmental stages (11.5-15.5 dpc), with higher contribution to the total number of neural precursors cells detected (EGF-responsive plus bFGF-responsive) at early stages and in the dorsal region. We show that the differentiation effect of bFGF resulted in the appearance of the mRNA coding for the EGF receptor. Our data suggest that bFGF-responsive neural precursors are the source of EGF-responsive neural precursors. 相似文献
12.
The induction of luteinizing hormone (LH) receptors was studied in granulosa cells prepared from the ovaries of hypophysectomized diethylstilbestrol-treated immature rats. Incubation of granulosa cells for 48 h with increasing concentrations of follicle-stimulating hormone (FSH) or choleragen caused parallel rises in cAMP levels and LH receptors. These observations, with the finding that 8-Bromo-cAMP also induced LH receptor formation, indicate that hormonal stimulation of LH binding sites is mediated by cAMP. Peptide hormones that inhibited FSH-stimulated cAMP production, such as epidermal growth factor (EGF) and a gonadotropin-releasing hormone agonist (GnRHa), also prevented LH receptor formation. GnRHa and EGF had negligible effects on FSH-stimulated cAMP production from 0 to 24 h of culture, but reduced cAMP accumulation by 80% and 90%, respectively, from 24 to 48 h when the majority of LH receptors appeared. FSH-sensitive adenylate cyclase activity, as measured by the conversion of (3H)-ATP to (3H)-cAMP, was inhibited by GnRHa and EGF at 48 h of culture. EGF and GnRHa also reversed the inhibition of ectophosphodiesterase activity caused by FSH in granulosa cells between 48 and 72 h of culture. Both EGF and GnRHa inhibited induction of LH receptors by 8-Bromo-cAMP, suggesting that their effects are also on cAMP action. Addition of GnRHa, but not EGF, between 36 and 48 h of culture completely prevented further increases in LH receptors induced by 8-Bromo-cAMP, indicating that the inhibitory action of GnRHa can be initiated at later times during granulosa cell differentiation, whereas full expression of EGF action requires a longer period. These results demonstrate that EGF and GnRH inhibit FSH-induced LH receptor formation in the granulosa cell by reducing hormone-dependent cAMP production and also by impairing the ability of cAMP to stimulate LH receptor formation. 相似文献
13.
Xiaoheng Li Yiyan Wang Qiqi Zhu Kaiming Yuan Zhijian Su Fei Ge Ren‐Shan Ge Yadong Huang 《Journal of cellular and molecular medicine》2020,24(13):7313-7330
Epidermal growth factor (EGF) has many physiological roles. However, its effects on stem and progenitor Leydig cell development remain unclear. Rat stem and progenitor Leydig cells were cultured with different concentrations of EGF alone or in combination with EGF antagonist, erlotinib or cetuximab. EGF (1 and 10 ng/mL) stimulated the proliferation of stem Leydig cells on the surface of seminiferous tubules and isolated CD90+ stem Leydig cells and progenitor Leydig cells but it blocked their differentiation. EGF also exerted anti‐apoptotic effects of progenitor Leydig cells. Erlotinib and cetuximab are able to reverse EGF‐mediated action. Gene microarray and qPCR of EGF‐treated progenitor Leydig cells revealed that the down‐regulation of steroidogenesis‐related proteins (Star and Hsd3b1) and antioxidative genes. It was found that EGF acted as a proliferative agent via increasing phosphorylation of AKT1. In conclusion, EGF stimulates the proliferation of rat stem and progenitor Leydig cells but blocks their differentiation. 相似文献
14.
John J. Wille Mark R. Pittelkow Gary D. Shipley Robert E. Scott 《Journal of cellular physiology》1984,121(1):31-44
The effects of growth factors, hormones, and calcium on the growth and differentiation of secondary cultures of normal human prokeratinocytes, i.e., proliferative keratinocytes, derived from adult or neonatal skin were determined by culture in serum-free basal medium, MCDB 153. Clonal growth was achieved when MCDB 153 was supplemented with either epidermal growth factor (EGF) or bovine pituitary extract (BPE), provided insulin was present. In the absence of insulin, however, both EGF and BPE were required for clonal growth. Using this assay, it was established that colony-forming efficiency is independent of calcium concentrations above 0.03 mM and averages 56%; colony size, however, was influenced by calcium and EGF concentrations. Optimal clonal growth occurred in medium containing 10 ng/ml EGF and 0.3 mM calcium. By contrast, differentiation was enhanced by the combination of low EGF (0.1 ng/ml) and high calcium (2 mM). This suggests that an inverse relationship exists between the growth response (extent of clonal growth) and the differentiation response (extent of differentiation). These results suggest that proliferation and differentiation are regulated in an integrated manner. Detailed kinetic studies and cytofluorimetric and autoradiographic analyses also showed that exponentially growing secondary cultures of adult and neonatal prokeratinocytes have a 24-hour cell generation time with G1, S, G2, and M phases of 12, 8, 3, and 1 hours, respectively. In addition, the data show that such cells can be growth arrested in medium that does not induce differentiation and that such a procedure significantly limits the cell's subsequent proliferative potential. Furthermore, prolonged culture of adult (> 30 population doublings) and neonatal prokeratinocytes (> 50 population doublings) is associated with senescence and the G1 arrest of noncycling cells. 相似文献
15.
Epidermal growth factor (EGF) at 10 ng/ml reduces by over 50-fold the extracellular Ca2+ required for multiplication of normal human skin fibroblasts. Therefore, a Ca2+-related process may play a central role in the mechanism by which EGF exerts its effect on cell multiplication. 相似文献
16.
Epidermal growth factor (EGF) at 10 ng/ml reduces by over 50-fold the extracellular Ca2+ required for multiplication of normal human skin fibroblasts. Therefore, a Ca2+-related process may play a central role in the mechanism by which EGF exerts its effect on cell multiplication. 相似文献
17.
R. Born J. Kummermehr J. Griebel K. R. Trott 《Radiation and environmental biophysics》1995,34(4):233-237
Delayed reproductive death, the appearance of colonies with a reduced cell density (impaired colonies) and the number of giant cells per colony were investigated in murine fibrosarcoma cells after irradiation with 3 to 9 Gy of x-rays. Radiation survivors were replated after reaching confluence, which occurred after 13 to 15 doublings; this procedure was repeated three times. The replating efficiency decreased in a dose-dependent manner, the survivors of 9 Gy achieving only 30% of the plating efficiency of unirradiated cells. After the third replating, i.e. after 40 to 45 doublings, the plating efficiency of the survivors approached that of the controls. The median colony size of the survivors showed a similar dose-dependent decrease, which was pronounced after the first replating but still remained significant after the third replating. The fraction of impaired colonies was increased to more than 30% in 9-Gy survivors, and though abating, the increase was still significant even after the third replating. Evidence of residual damage was also provided by the presence of giant cells. For instance, after 6 Gy irradiation and 13 to 15 doublings, the proportion of colonies with giant cells was 60%, decreasing only to 45% after 40 to 45 doublings. The number of giant cells per colony was 1.4 in colonies arising immediately after 6 Gy, decreasing to 0.9 after the third replating. These results suggest that the proliferative capacity of surviving cells is depressed even longer than their clonogenic capacity. 相似文献
18.
Normal, thioglycollate-stimulated and BCG-activated mouse peritoneal macrophages were cultivated in vitro with the conditioned medium of mouse L-929 cells. The thioglycollate- and BCG-macrophages rapidly proliferated, whereas normal macrophages grew more slowly. A clear morphological difference between the three types of macrophages in the culture was observed. Glucocorticoids inhibited the growth of the macrophages at pharmacological concentrations. Other steroids, progesterone, diethylstilbesterol and testosterone in that order, had a far lower growth-inhibiting effect. Macrophages cultured with 10-6 M dexamethasone had a reduced antimicrobial effect on Candida parapsilosis compared with that of the untreated cells. Choleragen had the same effect on the macrophages as glucocorticoids. The toxin inhibited growth at a concentration as low as 10 pg/ml and cells treated with 1 ng of choleragen per ml had decreased antifungal activity. Similarly, Escherichia coli lipopolysaccharide at 10 ng/ml inhibited the growth of thioglycollate-macrophages. However, macrophages incubated with the lipopolysaccharide had enhanced anticandida activity. Thus, the immunosuppressors glucocorticoid and choleragen inhibited both the increase in the number of macrophages and the microbicidal activity of the phagocytes. Lipopolysaccharide, an immunostimulant, stimulated macrophage activity, but was toxic for cell growth. 相似文献
19.
Tsutomu Wada Kathleen M. Darcy Xiaoping Guan Margot M. Ip 《Journal of cellular physiology》1994,158(1):97-109
The effect of the tumor promoter phorbol 12-myristate 13-acetate (PMA) on proliferation and differentiation of normal mammary epithelial cells from 50-day-old virgin rats was investigated using a model system that allows for full morphological and functional development of the cells. In this model, mammary epithelial cells are grown within a reconstituted basement membrane in a defined serum-free medium. PMA at a concentration of 10?6 M effected translocation of protein kinase C from cytosol to membrane. At the same concentration, it stimulated cell proliferation both in the presence and absence of EGF, and this stimulation was observed even when PMA exposure was limited to 15 min at the time of each media change. In contrast to the effect on proliferation, PMA at concentrations of 10?7 and 10?6 M inhibited functional differentiation as assessed by casein accumulation. Phorbol 12,13-dibutyrate at 10?6 M also stimulated proliferation and inhibited casein accumulation and was more effective than PMA in both cases. In contrast, the nonactive tumor promoter 4-α PMA had no effect on either proliferation or differentiation. One of the most striking effects of PMA was its ability to stimulate an atypical ductal morphogenesis, as manifested by the formation of intricate web-like colonies, and to inhibit the development of the well-differentiated alveolar-like multilobular colonies. PMA was also shown to completely suppress the growth of the squamous-like colonies that develop when EGF is absent or deficient. These effects of phorbol esters in mammary epithelial cells to stimulate proliferation, inhibit functional differentiation, and stimulate the development of ductal colonies are consistent with the suggestion that the signal transduction pathways evoked by PMA could act to stimulate the growth of initiated cells or render normal cells more sensitive to carcinogen. © 1994 Wiley-Liss, Inc. 相似文献
20.
Telma Tiemi Schwindt Fabiana Louise Motta Gabriela Filoso Barnabé Cristina Gon?alves Massant Alessander de Oliveira Guimar?es Maria Elisa Calcagnotto Fabio Silva Concei??o Jo?o Bosco Pesquero Stevens Rehen Luiz E. Mello 《PloS one》2009,4(2)