共查询到20条相似文献,搜索用时 15 毫秒
1.
Angie Rizzino 《In vitro cellular & developmental biology. Plant》1984,20(10):815-822
Summary Transforming growth factors (TGFs) are a relatively new category of factors that induce the anchorage-independent growth of
non-transformed cells. These factors are usually detected by their ability to induce normal rat kidney (NRK) fibroblasts to
grow in soft agar. Until now, this assay has been performed in serum-containing medium (SCM). Unfortunately, the background
activity of this assay is variable and dependent on several factors, including passage number of the cells and the serum lot
used. Furthermore, the addition of either EGF or TGF-β alone results in the appearance of additional colonies, which decreases
the sensitivity of the assay. To circumvent these problems, serum-free media have been developed that support the growth of
the NRK cells at low density in both monolayer culture and soft agar. Long-term growth in monolayer cultures occurs in serum-free
medium supplemented with laminin, insulin, transferrin, epidermal growth factor (EGF), fibroblast growth factor (FGF) and
high density lipoprotein (HDL). Growth in soft agar occurs when TGFs are added to a serum-free medium, AIG medium, that contains
insulin, transferrin, FGF and HDL. In contrast to the background activity observed when the assay is performed in SCM, no
colonies form in the AIG medium unless TGFs are added and few, if any, colonies form if EGF or TGF-β are added alone. Thus,
the AIG medium provides an improved assay for TGFs. In addition, the AIG medium should prove useful for examining other factors,
including serum factors, for TGF activity.
Editor's Statement This communication describes a modification of the standard assay for transforming growth factors. The
techniques employed make use of advantages provided by recent advances in serum-free cell culture to provide a well-defined
detection system that is more sensitive than conventional procedures. Experimental approaches described in this article also
should be helpful in unraveling differences in cellular behavior encountered under anchorage-dependent vs. anchorage-independent
conditions. D. W. Barnes 相似文献
2.
The migration of rat liver epithelial cells induced by epidermal growth factor (EGF) was inhibited by cyclic AMP (cAMP) and cholera toxin, but not by cGMP, cAMP and cholera toxin also inhibited the expression of the EGF/transforming growth factor (TGF) alpha-inducible protein EIP-1 (Mr 47,000), but not that of other proteins induced by the growth factor. cAMP therefore specifically and selectively represses the EGF-induced expression of this protein, which by synthesis in the presence of tunicamycin and by enzymatic treatments was shown to be N-glycosylated and sialylated. The close correlation of the expression of EIP-1 with the growth factor-induced migration suggests that this glycoprotein is involved in the cellular translocation process. Modulation of cell migration and of EIP-1 expression through increased intracellular concentrations of cAMP indicate that factors operating through this signal system can modulate the phenotypic and gene expression changes mediated by the EGF-receptor. Identification of the ligand(s) that can cause the cAMP-mediated effects might be an important step towards understanding the regulation of liver cell migration in vivo. 相似文献
3.
Ted Gansler Wei-Chao Hsu T. Stokes Gramling Katherine A. Robinson Maria G. Buse Ned Blocker Linda Roy Sadie Green A. Julian Garvin Donald A. Sens 《In vitro cellular & developmental biology. Plant》1990,26(3):285-290
Summary Insulinlike growth factors (IGF) and epidermal growth factor (EGF) are produced in renal tissue, as are specific receptors
for these hormones. To evaluate the significance of these observations to regulation of renal tubular cell proliferation,
we have examined the interaction of IGF and EGF with cultured human proximal tubular epithelial cells (HPT). HPT cells showed
specific binding of IGF-1, insulin, and EGF. IGF-1 binding was inhibited by antibody to the type 1 IGF receptor (α-IR3). Insulin
receptors and type 1 IGF receptors were identified by bifunctional cross-linking. IGF-1, insulin, and EGF stimulated [3H]thymidine incorporation by 77, 73, and 87%, respectively. Haft maximal stimulation by IGF-1, insulin, and EGF was produced
with 4×10−9
M, 2.5×10−8
M, and 8×10−10
M concentrations of these hormones. α-IR3 inhibited stimulation of thymidine incorporation by IGF-1 and insulin but had no
effect in EGF-stimulated thymidine incorporation. EGF and high concentrations of insulin both stimulated cell proliferation
by 83 and 79%, respectively. These data are consistent with regulation of tubular epithelial proliferation by IGF-1, insulin,
and EGF and suggest that the mitogenic activity of both insulin and IGF-1 is mediated by the type 1 IGF receptor.
Supported by grants CA37887 and DK32889 from the National Institutes of Health, Bethesda, MD, and by a Medical University
of South Carolina institutional grant. 相似文献
4.
Masanori Ito Kazuhiro Yoshida Eikai Kyo Ayse Ayhan Hirofumi Nakayama Wataru Yasui Hisao Ito Eiichi Tahara 《Virchows Archiv. B, Cell pathology including molecular pathology》1990,59(1):173-178
We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), EGF
receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma
cell lines and 18 human colorectal carcinomas.
In surgically resected specimens of the 18 colorectal tumors, TGF-α, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various
levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly,
EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically
in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics.
All the colorectal carcinoma cell lines expressed TGF-α mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production
of TGF-α protein by DLD-1 and CoLo320DM cells was confirmed by TGF-α specific monoclonal antibody binding assay. The spontaneous3H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-α monoclonal antibody. PDGFA and PDGFB mRNA were also expressed
in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express
multi-loops of growth factors and that TGF-α produced by tumor cells functions as an autocrine growth factor in human colonic
carcinoma. 相似文献
5.
Angie Rizzino Peter Kazakoff John Nebelsick 《In vitro cellular & developmental biology. Plant》1990,26(5):537-542
Summary Previous studies have shown that cell density can regulate the binding of several growth factors. To determine whether cell
density exerts a uniform effect on the expression of epidermal growth factor (EGF) receptors, seven cell lines were examined
in detail. For each cell line, EGF binding was found to decrease as cell density increases. Scatchard analysis of the binding
data reveals that decreases in EGF binding are due to reductions in the number of cell surface EGF receptors. The only apparent
exception is the effect of cell density on the binding of EGF to A-431 cells. For these cells, increases in cell density lead
to two effects: decreases in the number of high affinity EGF receptors and increases in the total number of EGF receptors.
In addition to the effects of cell density on EGF receptors, it was determined that increases in cell density can coordinately
down-regulate receptors for as many as four different growth factors. Overall, the findings described in this report for EGF
and those previously described for transforming growth factor type-β (TGF-β) and fibroblast growth factor (FGF) demonstrate
the existence of a common mechanism for down-regulating growth factor receptors.
This work was supported by grants from the Nebraska Department of Health (89-51), the National Cancer Institute (Laboratory
Research Center Support Grant, CA36727), and the American Cancer Society (Core Grant ACS SIG-16).
EDITOR'S STATEMENT The paper by Rizzino et al. demonstrates that receptor number decreases as a function of cell density.
This may represent a mechanism by which cell proliferation is reduced as cell density increases. 相似文献
6.
M. J. Dixon M. J. M. Carette B. B. Moser M. W. J. Ferguson 《In vitro cellular & developmental biology. Animal》1993,29(1):51-61
Summary A novel culture technique, which supports the growth and differentiation of mouse embryonic palatal epithelial cells in the
absence of either an extracellular matrix substratum or feeder layers, has been developed. Using this technique we have investigated
the effects of exogenous transforming growth factor alpha (TGFα) and serum on extracellular matrix biosynthesis by primary
cultures of mouse embryonic epithelial sheets under defined experimental conditions. In all culture treatments (chemically
defined medium with and without TGFα or serum) the palatal epithelial sheets differentiated into three regionally distinct
cell phenotypes after 36 h. Nasal and oral cells differentiated into pseudostratified, cilliated columnar, and stratified
squamous keratinizing epithelium, respectively. In addition, basal medial edge epithelial (MEE) cells at the oral/nasal regional
interface assumed an elongated cobblestoned phenotype. In serum-free medium, collagen types IV and V, laminin, fibronectin,
and heparan sulphate proteoglycan were detected immunocytochemically throughout the entire epithelial sheet. Tenascin and
collagen IX were present almost exclusively in MEE cells. Types I, II, and III collagen were completely absent. Addition of
TGFα or serum universally increased the intensity of staining, most notably that for tenascin and collagen IX in MEE cells.
These results indicate that mouse embryonic palatal epithelial sheets can be maintained under defined culture conditions during
which they exhibit patterns of differentiation similar to those observed in vivo. TGFα, known to localize to the MEE in vivo,
can modulate palatal extracellular matrix biosynthesis, particularly by the MEE, suggesting a regulatory role for this factor.
The culture system is suitable for further investigating the effects of exogenous factors on mouse embryonic palatal epithelial
cell bioactivity and differentiation. 相似文献
7.
Growth factor regulation of proliferation in primary cultures of small intestinal epithelium 总被引:1,自引:0,他引:1
C. Booth G. S. Evans C. S. Potten 《In vitro cellular & developmental biology. Animal》1995,31(3):234-243
Summary Although the intestinal epithelium is one of the most rapidly renewing tissues, little is known about the major growth factors
that control the rate of cell replacement and migration. Recently, a primary culture model has been described for the developing
rat small intestinal epithelium, which permits epithelial growth while maintaining interactions with associated stromal cells,
thereby possessing several contextual advantages over established cell lines (Evans et al., 1992). We have used this model
to begin to determine the factors that may be involved in controlling intestinal epithelial cell proliferation. Under the
conditions examined, no single growth factor promoted exclusive proliferation of epithelial cells; stromal cell proliferation
was also apparent. The most potent stimulators of epithelial proliferation were insulin and insulin-like growth factor 1 (IGF-1).
These factors also appeared to inhibit migration of the epithelial cells. 5–10 ng/ml EGF, 5–20 ng/ml TGFα, and 10–20 ng/ml
PDGF also slightly increased epithelial cell numbers. Cell proliferation was inhibited by 0.1 ng/ml TGFβ-1. In Dulbecco’s
modified Eagle’s medium (DMEM) containing 0.25 IU/ml insulin, glucose levels of 2–3 g/liter permitted epithelial growth with
limited expansion of the stromal cell population. Higher levels of glucose further stimulated the nonepithelial cell types.
Transferrin was also a potent stimulator of both cell types. 相似文献
8.
Retroviruses expressing different levels of the normal epidermal growth factor receptor: biological properties and new bioassay 总被引:6,自引:0,他引:6
T J Velu L Beguinot W C Vass K Zhang I Pastan D R Lowy 《Journal of cellular biochemistry》1989,39(2):153-166
Two retroviral DNAs that encode the normal human epidermal growth factor (EGF) receptor hEGFR have been generated by inserting a hEGFR cDNA into two different retroviral vectors. One DNA (pCO11-EGFR-neo) also contained a linked selectable marker gene (neoR). The other (pCO12-EGFR) only expresses hEGFR. When introduced into NIH3T3 cells, the two DNAs and the viruses derived from them induced a fully transformed phenotype, including focal transformation and growth in agar or low serum, but transformation depended entirely upon EGF being present in the growth medium. Compared with pCO11-EGFR-neo, pCO12-EGFR induced EGF-dependent transformation 2-5 times more efficiently and expressed higher numbers of receptors (4 x 10(5) vs. 1 x 10(5) EGF receptors per cell). The results indicate that transforming potential is directly related to the number of EGF receptors. In defined, serum-free medium that contained only very low concentrations of insulin (0.6 microgram/ml) and transferrin (0.6 micrograms/ml), hEGFR-virus infected cells were able to grow with EGF as the only growth factor. Moreover, daily incubation of the cells with EGF for only 30 min was sufficient to induce growth. NR6 cells, which lack endogenous EGF receptors, were transformed as efficiently as NIH3T3 cells by the hEGFR virus. The dose-dependent growth response to EGF of infected NR6 cells grown in serum-free medium can be used as a highly sensitive bioassay for the quantitative assessment of EGF and transforming growth factor type alpha (TGF alpha). This bioassay is at least as sensitive as previously reported radioimmunoassays and can measure a much wider concentration range (10 pg-100 ng/ml). Uninfected NR6 cells or NR6 cells infected by helper virus alone can be used as controls for the EGF specificity of growth stimulation. 相似文献
9.
Donald J. Sarubbi Ramaswamy Narayanan Nitin T. Telang Michael J. Newman 《In vitro cellular & developmental biology. Plant》1990,26(12):1195-1201
Summary Novel or modified serum-free media were developed for the anchorage-dependent growth of nontransformed murine mammary epithelial
cells (MMEC) and Balb/MK murine keratinocytes respectively. Growth rates for both cell lines were similar in serum-containing
and serum-free media. The serum-free media were used to evaluate potential mechanisms of epithelial cell growth regulation
by type 1 transforming growth factor β(TGF-β1). The growth of MMEC and Balb/ MK cells was reversibly inhibited 40–65% in a
time- and dose-dependent fashion by TGF-β1 under both serum-containing and serum-free conditions. Constitutive over-expression
of a stranfected c-myc oncogene inMMEC did not result in loss of sensitivity to growth inhibition by TGF-β1. In addition, Balb/MK and MMEC growth
inhibition by TGF-β1 was not potentiated by polynsaturated fatty acids or reversed by vitamin E. Expgenous type V collagen
was able to mimic the inhibitory effects of TGF-β1 on the serum-free growth of Balb/MK and MMEC. In contrast, collagen type
I and IV, fibronectin and laminin did not inhibit the growth of these cells. The type V collagen used was not contaminated
with TGF-β, and subsaturating, but not saturating concentrations of type V collagen and TGF-β1 were additive with respect
to Balb/MK and MMEC growth inhibition. These results demonstrate that nontransformed epithelial cell growth inhibition by
TGF-β1 is mediated by mechanisms distinct from those observed with certain carcinoma and melanoma cells. Our results also
suggest the possible involvement of type V collagen in Balb/MK and MMEC growth inhibition by TGF-β1.
This work was supported, in part, by grant #R29 CA 44741 from the National Institutes of Health, Bethesda, MD to NTT. 相似文献
10.
Lin-Chang Chiang Janet Silnutzer James M. Pipas David W. Barnes 《In vitro cellular & developmental biology. Plant》1985,21(12):707-712
Summary NIH3T3 cells grow in a serum-free basal nutrient medium supplemented with fibronectin, transferrin, insulin, epidermal growth
factor (EGF) and high density lipoprotein (HDL). The individual omission from the serum-free medium of insulin, EGF, or HDL
results in greatly reduced cell growth. These growth-restrictive conditions can be used to select for cells transformed with
SV40, the polyomavirus middle T antigen gene, the activated humanras gene, and the mouse c-myc gene.
This work was supported by grants ES-00-210 from the National Institutes of Health (NIEHS) and MV-182 from the American Cancer
Society.
Dr. L.-C. Chiang is a Visiting Research Scientist from PPG Industries, Inc.
Editor’s statement This paper represents a new approach to the identification of oncogenes that would escape the screening
methods currently in use. Inherent in the method is the assignment of function to oncogenes. 相似文献
11.
Rat mammary carcinoma (RMC) cells derived from serially transplantable mammary tumors are independent of epidermal growth factor (EGF) for long-term growth in serum-free medium. This phenotype is in contrast to that of normal mammary epithelial cells or cells derived from nontransplantable tumors that express an absolute requirement for EGF for growth in culture. The results of the experiments reported here indicate that EGF-independent RMC cells secrete a growth factor with potent EGF-like mitogenic activity. Conditioned media obtained from these cells can substitute for EGF for the growth of the EGF-dependent cell line MCF-10. This growth factor is neither EGF nor transforming growth factor alpha and does not compete with 125I-EGF for binding to EGF receptors. Phosphotyrosine Western blot analysis of lysates obtained from EGF-independent RMC cells revealed the presence of a 190 kilodalton (kDa) protein that was distinct from the EGF receptor. Similarly, growth of MCF-10 cells to confluence in serum-free medium supplemented with conditioned medium growth factor in place of EGF resulted in the disappearance of the EGF receptor band and appearance of the 190 kDa band in phosphotyrosine Western blots. The 190 kDa tyrosine-phosphorylated protein detected in cells stimulated by the conditioned medium factor is unlikely to be the c-erbB-2 protein, as indicated by negative results in immunoprecipitation experiments and in vitro kinase assays. In summary, EGF-independent RMC cells secrete a factor with potent EGF-like mitogenic activity. This suggests that an autocrine loop involving this growth factor mediates EGF independence in these cells. 相似文献
12.
Wounding corneal epithelium establishes a laterally oriented, DC electric field (EF). Corneal epithelial cells (CECs) cultured in similar physiological EFs migrate cathodally, but this requires serum growth factors. Migration depends also on the substrate. On fibronectin (FN) or laminin (LAM) substrates in EF, cells migrated faster and more directly cathodally. This also was serum dependent. Epidermal growth factor (EGF) restored cathodal-directed migration in serum-free medium. Therefore, the hypothesis that EGF is a serum constituent underlying both field-directed migration and enhanced migration on ECM molecules was tested. We used immunofluorescence, flow cytometry, and confocal microscopy and report that 1) EF exposure up-regulated the EGF receptor (EGFR); so also did growing cells on substrates of FN or LAM; and 2) EGFRs and actin accumulated in the cathodal-directed half of CECs, within 10 min in EF. The cathodal asymmetry of EGFR and actin staining was correlated, being most marked at the cell-substrate interface and showing similar patterns of asymmetry at various levels through a cell. At the cell-substrate interface, EGFRs and actin frequently colocalized as interdigitated, punctate spots resembling tank tracks. Cathodal accumulation of EGFR and actin did not occur in the absence of serum but were restored by adding ligand to serum-free medium. Inhibition of MAPK, one second messenger engaged by EGF, significantly reduced EF-directed cell migration. Transforming growth factor beta and fibroblast growth factor also restored cathodal-directed cell migration in serum-free medium. However, longer EF exposure was needed to show clear asymmetric distribution of the receptors for transforming growth factor beta and fibroblast growth factor. We propose that up-regulated expression and redistribution of EGFRs underlie cathodal-directed migration of CECs and directed migration induced by EF on FN and LAM. 相似文献
13.
Leah S. Royce Bruce J. Baum 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1991,1092(3):401-403
An established line of human oral epithelial cells exhibits chemotaxis to epidermal growth factor (EGF). The directed migration of these cells is time dependent with an approximate 10-fold increase in the number of cells responding to the chemoattractant by 6 h. Cell migration occurs in a concentration dependent manner with maximal response at ≈ 1 ng/ml. This maximal chemotactic response occurs within the physiologic concentration range for EGF found in human saliva. These data suggest that EGF may be important for the maintenance of an intact oral epithelial (mucosal) barrier, and may play a vital role in oral mucosal wound healing. 相似文献
14.
Induction of rat liver epithelial cell migration by epidermal growth factor (EGF) changes the expression pattern of secreted proteins. The expression of the early induced glycoprotein EGF-inducible protein No. 1 (EIP-1) correlates with the migratory behavior of both normal and Ha-ras-transformed, tumorigenic cells and is deposited into the ECM migration tracks. The sequence of two clones from a cDNA library of EGF-induced cells and the amino terminal sequence of the purified protein revealed that EIP-1 is identical to rat plasminogen activator inhibitor 1 (PAI-1). Based on the migration-linked expression pattern of EIP-1/PAI-1 it is proposed that the inhibitor is required for the migration of these cells, but not sufficient to stimulate it. 相似文献
15.
Extracellular matrix (ECM) modulates the EGF-induced migration of liver epithelial cells in serum-free,hormone-supplemented medium 总被引:2,自引:0,他引:2
Summary The influence of the extracellular matrix (ECM) glycoproteins collagen, IV laminin (LN), and fibronectin (FN) on the in vitro
migration of epithelial cells was studied using the ECM migration track method (4) with preparations immunostained for LN
and FN. The locomotion of rat liver epithelial cells stimulated to migrate in serum-free medium by epidermal growth factor
(EGF) in the presence of the protein per cm2. Neither LN nor collagen IV decreased the number of migrating cells, indicating that the inhibition is a specific effect
of fibronectin. The data also indicate that the FN-mediated inhibition of migration is an additional and not alternative mechanism
to the well-established contact inhibition of locomotion (1) which also occurs in liver epithelial cell cultures. The system
is being used for a further analysis of the factors that influence migration of normal and neoplastic epithelial cells and
the biochemical mechanisms underlying the migration reaction.
Editor’s Statement This paper describes new and heretofore neglected aspects of EGF and fibronectin action on the migratory
behavior of cultured cells. Gordon H. Sato 相似文献
16.
Yuji Hiraki Hiroyuki Inoue Yukio Kato Michiko Fukuya Fujio Suzuki Ph.D 《Molecular and cellular biochemistry》1987,76(2):185-193
Summary The somatomedin-like growth factors cartilage-derived factor (CDF) and multiplication-stimulating activity (MSA) stimulate DNA synthesis and proliferation of rabbit costal chondrocytes under serum-free conditions. Previously, we suggeted that CDF and MSA act on chondrocytes in an early G1 phase to stimulate DNA synthesis. CDF and MSA have synergistic effects with epidermal growth factor (EGF) or fibroblast growth factor (FGF) in stimulating DNA synthesis of the cells. The mode of combined action of CDF or MSA with EGF or FGF in chondrocytes was studied by sequential treatments with these agents. EGF or FGF had synergistic effects with CDF or MSA in stimulating DNA synthesis, even when added 10 h after the latter. Synergism was also observed in cells pretreated with CDF or MSA; That is, the cultures were treated for 5 h with CDF or MSA and then washed, and treated with FGF or EGF. However, when CDF or MSA was added more than 5 h after EGF or FGF, no synergism of effects was observed. These findings suggest that the cultured chondrocytes become activated to interact with FGF or EGF for commitment to DNA synthesis when they are exposed to somatomedin-like growth factors at an early stage in the G1 phase. Thus chondrocytes are under a different mechanism of growth control from fibroblastic cells.Abbreviations CDF
cartilage-derived factor
- MSA
multiplication-stimulating activity
- EGF
epidermal growth factor
- FGF
fibroblast growth factor 相似文献
17.
Terry L. Riss Kenneth P. Karey B. Daniel Burleigh David Farker David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1988,24(11):1099-1106
Summary A serum-free clonal density growth assay was developed for the quantification of the biological activity of human recombinant
insulin-like growth factor I (IGF-I). The assay measures IGF-I stimulated growth of Balb/c 3T3 cells cultured over 4 d on
poly-d-lysine-coated plastic surfaces in a serum-free medium formulation composed of a 1∶1 (vol/vol) mixture of Ham's F12 and Dulbecco's
modified Eagle's media, supplemented with 3.0 ng/ml bovine basic fibroblast growth factor (bFGF), 10 μg/ml human transferrin,
100 μg/ml ovalbumin, and 1.0 μM dexamethanose. Low-temperature trypsinization of serum-supplemented stock cultures combined with the use of poly-d-lysine-coated plates made it unnecessary to use serum or fibronectin to promote cell attachment and survival. Serum-free
growth conditions were optimized with respect to the concentrations of the supplements. Addition of IGF-I resulted in 3.5-fold
more cells than control cultures without IGF-I after 4 d. Deletion of bFGF resulted in no IGF-I stimulation of growth. The
concentrations of various preparations of IGF-I required to achieve one-half maximal stimulation of cell number (ED50), ranged between 1.25 and 4.7 ng/ml. In parallel assays, IGF-I was 6.6 times more potent than human recombinant insulin-like
growth factor II and 32 times more potent than insulin. When cells were seeded into medium containing IGF-I, transferrin,
ovalbumin, and dexamethasone but no bFGF, growth was minimal. Dose-response addition of bFGF showed an ED50, of 0.9 ng/ml. The methods reported are useful to monitor the biological potency of recombinant and natural-source growth
factors as well as providing a new means of studying the multiple growth factor requirements of Balb/c 3T3 cells in cultures.
This work was supported by a contract from IMCERA Bioproducts, Inc. 相似文献
18.
Gary L. Bradshaw George R. Dubes 《In vitro cellular & developmental biology. Plant》1983,19(10):735-742
Summary Factors requred as supplements to basal tissue culture medium for the multiplication of cells of the cloned rat fibroblast
line called normal rat kidney 49F (NRK-49F) were identified as epidermal growth factor, fibronectin, insulin, and retinoic
acid. The requirement for fibronectin was manifested on a clean glass surface but not on the polystyrene plastic surface tested.
This set of required factors differs substantially from the factor sets required by the Madin-Darby, canine kidney (MDCK)
and LLC-PK1 pig kidney lines of epithelial cells and the baby hamster kidney 21 (BHK-21) line of fibroblasts. The serum-free medium supplemented
with the four factors supported rapid growth of NRK-49F cells when the initial cell population density was about 8,000 cells/cm2 or greater. At lower initial densities, cell multiplication was markedly increased by adding serum-free medium that had been
conditioned by NRK-49F cells. Cell growth rate in the defined serum-free medium stayed high through two serial passages but
declined in the third serial passage unless the cell-conditioned medium was added. 相似文献
19.
20.
Pei-San Tsai Francis-Dean A. Uchima Susan T. Hamamoto Howard A. Bern 《In vitro cellular & developmental biology. Animal》1991,27(6):461-468
Summary Mouse vaginal epithelial cells were isolated from intact 21-day-old BALB/cCrgl mice and cultured in a serum-free medium (SF20: basal medium supplemented with insulin, epidermal growth factor, transferrin, and bovine serum albumin—fraction V) to examine
the proliferation, differentiation, and specificity of estrogen-induced growth retardation in vitro. Histologic and ultrastructural
studies showed that vaginal epithelial cells undergo differentiative changes in vitro in the absence of estrogen, and that
these changes are similar to those induced in vivo by estrogen. Addition of 17β-estradiol inhibited cellular proliferation
in a dose-dependent manner. Whereas other estrane derivatives (17α-estradiol and estriol) also significantly retarded cellular
proliferation, cholesterol, testosterone, and progesterone had no effect. Keoxifene, an antiestrogen, significantly reversed
estrogen-induced growth inhibition, resulting in proliferation of estrogen-treated cells equivalent to that of the untreated
control. The results suggest that both proliferation and differentiation of prepubertal mouse vaginal epithelial cells in
vitro are estrogen-independent, and that the growth inhibition is a specific estrogen-induced response.
This work was supported by grants CA-05388 and CA-09041 from the National Institutes of Health, Bethesda, MD. 相似文献