scholarly journals Distribution of mRNA for human epiregulin, a differentially expressed member of the epidermal growth factor family

1997 ◽  
Vol 326 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Hitoshi TOYODA ◽  
Toshi KOMURASAKI ◽  
Daisuke UCHIDA ◽  
Sigeo MORIMOTO
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Tumour Cell ◽  
Biologically Active ◽  
Soluble Form ◽  
Egf Receptors ◽  
Epidermal Growth ◽  
Tumour Cell Lines ◽  
Egf Family

We have recently identified epiregulin as a new growth regulator and a member of the epidermal growth factor (EGF) family. Epiregulin has certain characteristics that are different from those of the classical members of the EGF family, EGF and transforming growth factor α, including mitogenic responses on several normal cells and binding to EGF receptors on epidermoid carcinoma A431 cells. In the present study we cloned and identified the expression of human epiregulin transcript. The human epiregulin gene encoded a 163-residue putative transmembrane precursor containing an EGF-like domain in the internal segment, and the structural organization was similar to that of other members of the EGF family that bind to EGF receptors. Northern blot analysis showed the expression of human epiregulin to be mainly on peripheral blood macrophages and the placenta in normal tissues, and was highest on epithelial tumour cell lines in various types of tumour cell lines. The expression profile was quite different from that of other members of the EGF family in normal and tumour cells. Recombinant expression in mammalian cells also showed that human epiregulin was secreted as a soluble form of approx. 5 kDa that is biologically active on the basis of the stimulation of DNA synthesis. Our findings suggest that epiregulin is involved in certain physiological processes such as maintenance or development of normal cell growth, and the progression of carcinomas.

scholarly journals A dual immunocytochemical assay for oestrogen and epidermal growth factor receptors in tumour cell lines

1994 ◽  
Vol 26 (4) ◽  
pp. 306-310 ◽  
Author(s):  
A. K. Sharma ◽  
K. Horgan ◽  
R. A. McClelland ◽  
A. G. Douglas-Jones ◽  
T. Van Agthoven ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Tumour Cell ◽  
Growth Factor Receptors ◽  
Epidermal Growth Factor Receptors ◽  
Immunocytochemical Assay ◽  
Epidermal Growth ◽  
Tumour Cell Lines

scholarly journals Loss of epidermal growth factor receptors and release of transforming growth factors do not correlate with sarcoma virus-transformation in clonally-related NIH/3T3-derived cell lines

1985 ◽  
Vol 229 (1) ◽  
pp. 119-125 ◽  
Author(s):  
K D Brown ◽  
D M Blakeley ◽  
P Roberts ◽  
R J Avery
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Line ◽  
Conditioned Medium ◽  
Cell Lines ◽  
Egf Receptors ◽  
3T3 Cells ◽  
Sarcoma Virus ◽  
Epidermal Growth ◽  
Nih 3T3

Transformation of NIH/3T3 cells by Kirsten murine sarcoma virus (MSV) caused a dramatic reduction in the number of cell-surface receptors for epidermal growth factor (EGF). However, the number of EGF receptors remained at a very low level in a non-tumourigenic revertant cell line isolated from the virus-transformed cells, indicating that an increase in EGF receptors is not a requirement for the phenotypic reversion of Kirsten MSV-transformed 3T3 cells. Serum-free conditioned medium from normal and virus-transformed cell lines contained similar amounts of cell growth-promoting activity as assayed by the ability to stimulate DNA synthesis in quiescent Swiss 3T3 cell cultures. However, the concentrated conditioned medium from these cell lines showed no evidence of beta-transforming growth factor (TGF) activity as assayed by promotion of anchorage-independent growth of untransformed normal rat kidney (NRK) fibroblasts in agarose. The cellular release of alpha-TGF activity was assayed by measuring the ability of concentrated conditioned medium to inhibit the binding of 125I-EGF to Swiss 3T3 cells. Conditioned medium protein from the virus-transformed cell line inhibited 125I-EGF binding but only to the same extent as conditioned medium protein prepared from the untransformed cell line. The alpha-TGF secretion by these cell lines was estimated to be 30-45-fold lower than the level of alpha-TGF released by a well-characterized alpha-TGF-producing cell line (3B11). These results suggest that the induction of TGF release is not a necessary event in the transformation of NIH/3T3 cells by Kirsten MSV.

scholarly journals Direct visualization of the binding and internalization of a ferritin conjugate of epidermal growth factor in human carcinoma cells A-431.

1979 ◽  
Vol 81 (2) ◽  
pp. 382-395 ◽  
Author(s):  
H T Haigler ◽  
J A McKanna ◽  
S Cohen
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Carcinoma Cells ◽  
Biologically Active ◽  
Molar Ratio ◽  
Multivesicular Bodies ◽  
Egf Receptors ◽  
Human Carcinoma ◽  
Epidermal Growth

We have prepared a conjugate of epidermal growth factor (EGF) and ferritin that retains substantial binding affinity for cell receptors and is biologically active. Glutaraldehyde-activated EGF was covalently linked to ferritin to produce a conjugate that contained EGF and ferritin in a 1:1 molar ratio. The conjugate was separated from free ferritin by affinity chromatography using antibodies to EGF. Monolayers of human epithelioid carcinoma cells (A-431) were incubated with EGF:ferritin at 4 degrees C and processed for transmission electron microscopy. Under these conditions, approximately 6 X 10(5) molecules of EGF:ferritin bound to the plasma membrane of each cell. In the presence of excess native EGF, the number of bound ferritin particles was reduced by 99%, indicating that EGF:ferritin binds specifically to cellular EGF receptors. At 37 degrees C, cell-bound EGF:ferritin rapidly redistributed in the plane of the plasma membrane to form small groups that were subsequently internalized into pinocytic vesicles. By 2.5 min at 37 degrees C, 32% of the cell-bound EGF:ferritin was localized in vesicles. After 2.5 min, there was a decrease in the proportion of conjugate in vesicles with a concomitant accumulation of EGF:ferritin in multivesicular bodies. By 30 min, 84% of the conjugate was located in structures morphologically identified as multivesicular bodies or lysosomes. These results are consistent with other morphological and biochemical studies utilizing 125I-EGF and fluorescein-conjugated EGF.

Specific binding sites for epidermal growth factor and its effect on human chorionic gonadotrophin secretion by cultured tumour cell lines: comparison between trophoblastic and non-trophoblastic cells

1982 ◽  
Vol 101 (2) ◽  
pp. 281-286 ◽  
Author(s):  
Yukio Hirata ◽  
Satoru Sueoka ◽  
Masahito Uchihashi ◽  
Yoshio Yoshimoto ◽  
Takuo Fujita ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Binding Sites ◽  
Specific Binding ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Specific Binding Sites ◽  
Epidermal Growth ◽  
Tumour Cell Lines

Abstract. Using human trophoblastic (SCH) and non-trophoblastic (HeLa S3) tumour cell lines, specific binding sites for epidermal growth factor (EGF), a potent stimulator of growth in many tissues, and its effect on secretion of human chorionic gonadotrophin (hCG) and/ or its subunits were compared between these two tumour cells. Both SCH and HeLa S3 cells possessed two populations of specific binding sites for 125I-labelled EGF: the high affinity (Kd ∼10−10m) and the low affinity (Kd ∼ 7 × 10−10 m) system. Tetradecanoyl phorbol acetate (TPA), a tumour promotor, showed a potent competitor of labelled tracer binding to its receptor sites in both cell lines. EGF stimulated both hCG-α and hCG and/or hCG-β secretion in a dose-responsive manner from SCH cells, whereas it had no effect on hCG-α secretion from HeLa S3 cells. In contrast, dibutyryl cyclic AMP plus theophylline, a phosphodiesterase inhibitor, enhanced hCG-α secretion from both cells, while TPA had no effect in either cells. These data suggest that EGF may play a physiological role in hCG secretion from trophoblastic tissues and that the mechanism by which hCG and/or its subunits are secreted may differ between trophoblastic and non-trophoblastic tumour cells.

scholarly journals Inhibition of protein breakdown by epidermal growth factor in IMR90 human fibroblasts and other mammalian cell lines

1983 ◽  
Vol 210 (1) ◽  
pp. 251-258 ◽  
Author(s):  
J M Gunn ◽  
J B Bodner ◽  
S E Knowles ◽  
F J Ballard
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Phorbol Esters ◽  
Human Fibroblasts ◽  
Inhibitory Effect ◽  
Protein Breakdown ◽  
Egf Receptors ◽  
Mammalian Cell Lines ◽  
Epidermal Growth

1. Epidermal growth factor (EGF) inhibits intracellular protein breakdown in IMR90 human fibroblasts and other cell lines having EGF receptors. 2. Inhibition is achieved within 1 h of exposure to the growth factor and is reversed equally rapidly upon removal of EGF. 3. EGF inhibits protein breakdown and stimulates protein and DNA labelling with similar dependency on concentration. Half-maximal effects for all processes with IMR90 and AG2804 cell lines occur at 0.2 nM- and 0.05 nM-EGF respectively. 4. EGF and insulin effects on protein breakdown are additive only when the factors are included at suboptimal concentrations. 5. The apparent Kd for EGF binding in several cell lines is approximately 10-fold higher than the concentration needed for half-maximal inhibition of protein breakdown. 6. Down-regulation of EGF receptors in IMR90 cells produced a 60% decrease in the binding of 125I-labelled EGF. This was accompanied by a displacement of the concentration curve for EGF inhibition of protein breakdown by approximately two orders of magnitude, suggesting that protein breakdown can no longer respond to the down-regulated receptor-growth-factor complex. 7. Phorbol esters decrease the inhibitory effect of EGF, but not of insulin, on protein breakdown in IMR90 cells.

scholarly journals The combination of epidermal growth factor and transforming growth factor-beta induces novel phenotypic changes in mouse liver stem cell lines

1997 ◽  
Vol 110 (24) ◽  
pp. 3117-3129 ◽  
Author(s):  
R.J. Isfort ◽  
D.B. Cody ◽  
S.B. Stuard ◽  
C.J. Randall ◽  
C. Miller ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Family Members ◽  
Oval Cell ◽  
Tgf Beta ◽  
Epidermal Growth ◽  
Egf Family

Mouse liver stem cell (oval cell) lines were investigated in order to determine the role which two families of growth and differentiation factors (GDFs), epidermal growth factor (EGF) family and transforming growth factor beta (TGF-beta) family, play in liver regeneration. EGF family members, including EGF, amphiregulin, betacellulin, heparin-binding epidermal growth factor, and TGF-alpha, were mitogenic for oval cell lines while TGF-beta family members, including TGF-beta1, TGF-beta2 and TGF-beta3, inhibited mitogenesis and induced apoptosis in oval cell lines. Surprisingly, the combination of EGF family members and TGF-ss family members resulted in neither proliferation nor apoptosis but instead in a novel cellular response, cellular scattering in tissue culture and morphological differentiation in Matrigel. Analysis of the signal transduction pathways activated by exposure of oval cell lines to either EGF, EGF+TGF-beta, or TGF-beta indicated that novel combinations of intracellular signals result following stimulation of the cells with the combination of EGF+TGF-beta. These data reveal that the dynamics of synergistic GDF action following tissue injury and regeneration results in a new level of complexity not obvious from the study of individual GDFs.

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