Regulation of epidermal growth factor and insulin-like growth factor I receptors by estradiol and progesterone in normal and neoplastic endometrial cell cultures

Growth factors are polypeptides which regulate cell proliferation through binding to specific receptor proteins. Normal and neoplastic human endometrium have been shown to express epidermal growth factor (EGF) and insulin-like growth factor I (IGF-1) receptors. Endometrial cell cultures were used to test modulation of EGF and IGF-1 receptors in response to steroid hormones. Endometrial gland and stroma cells were separated by enzymatic dispersion and were incubated in medium containing estradiol (10, 100, or 1000 pg/ml) or progesterone (1, 10, or 100 ng/ml) followed by radioligand assays. Normal endometrial cultures (n = 6) treated with estradiol demonstrated 40% less EGF binding than control cultures (P less than 0.05), while IGF-1 binding was unaffected. Stromal cells treated identically decreased in only one treatment group. Progesterone treatment stimulated a significant increase in EGF and IGF-1 receptors in gland cultures. Cultures derived from adenocarcinoma (n = 2) demonstrated decreased EGF binding compared with normal endometrium (P less than 0.05). Carcinoma cells treated with progesterone resulted in a dose-dependent increase in EGF binding over control (P less than 0.05). These data illustrate effects of steroid hormones upon growth factor receptors in human endometrium, and suggest involvement of growth factors in the regulation of normal and neoplastic endometrial growth.     

Progesterone-induced secretion of growth hormone,insulin-like growth factor I and prolactin by human breast cancer explants

The aim of the study was to evaluate the potential of human breast cancer tissue to secrete growth hormone (GH) ,insulin-like growth factor I (IGF-I) and prolactin in response to 10^?7 M progesterone stimulation. Explants were divided according to estrogen receptor (ER)/progesterone receptor (PR) phenotype (ER(?)PR(?); ER(+)PR(?); ER(+)PR(+); ER(?)PR(+)). Our results show distinct differences in cultured breast cancer tissue responses to progesterone stimulation with regard to secretion of proliferative agents such as GH ,IGF-I and prolactin. All but ER(?)PR(?) breast cancer cell types responded in vitro to progesterone stimulation with an increase in local GH secretion ,while in non-malignant tissue progesterone induced local GH secretion only in PR(+) cells. Moreover ,only in PR(+) cells did progesterone stimulate local IGF-I and prolactin secretion ,in both malignant and non-malignant tissue. This study provides evidence for the first time that in PR(+) breast cancer tissue ,progesterone may increase GH ,prolactin and IGF-I secretion in both malignant and surrounding non-malignant tissue. These hormones may act as local growth factors that stimulate the proliferation of mammary tumors.     

The binding of epidermal growth factor to the human uterus and leiomyomata in women rendered hypo-oestrogenic by continuous administration of an LHRH agonist

The binding of epidermal growth factor (EGF) to human myometrium and leiomyomata was assessed in a group of women rendered hypo-oestrogenic with the LHRH agonist Zoladex (ICI 118630). The results were compared with those obtained with tissues from women with normal cycles. In normal women, the specific binding of radiolabelled [125I] EGF to both myometrial and fibroid homogenates did not vary during the menstrual cycle, but the specific binding of [125I] EGF to fibroid in women treated with LHRH agonist was significantly less than in the untreated group. Since the hypo-oestrogenic state induced by the agonist is associated with a decrease in fibroid size, the results suggest that the effect of oestrogen on fibroid tissue may partly be mediated by EGF.     

Effect of insulin-like growth factor I on deoxyribonucleic acid synthesis in cultured human granulosa cells

Insulin-like growth factor I (IGF-I) has been proposed to be an autocrine/paracrine factor involved in granulosa cell proliferation and differentiation. The present study focuses on a possible mitogenic effect of IGF-I in human granulosa cells. Insulin-like growth factor I (1 to 10 ng/mL) significantly stimulated 3H-thymidine incorporation in granulosa cells obtained from both natural cycles and from patients stimulated for in vitro fertilization, whereas luteinizing hormone (LH, 10 ng/mL), follicle-stimulating hormone (FSH, 10 ng/mL) and epidermal growth factor (EGF, 10 ng/mL) had no apparent effect on deoxyribonucleic acid (DNA) synthesis under these conditions. Luteinizing hormone and FSH stimulated progesterone secretion whereas IGF-I and EGF were without effect. Our observations that IGF-I stimulates DNA synthesis in human granulosa cells is in agreement with previous reports, in other species, indicating that IGF-I might be of importance for granulosa cell proliferation.     

The binding of epidermal growth factor to the human uterus and leiomyomata in women rendered hypooestrogenic by continuous administration of an LHRH agonist

Summary. The binding of epidermal growth factor (EGF) to human myometrium and leiomyomata was assessed in a group of women rendered hypo-oestrogenic with the LHRH agonist Zoladex (ICI118630). The results were compared with those obtained with tissues from women with normal cycles. Tn normal women, the specific binding of radiolabelled [¹²⁵I] EGF to both myometrial and fibroid homogenates did not vary during the menstrual cycle, but the specific binding of [¹²⁵I] EGF to fibroid in women treated with LHRH agonist was significantly less than in the untreated group. Since the hypo-oestrogenic state induced by the agonist is associated with a decrease in fibroid size, the results suggest that the effect of oestrogen on fibroid tissue may partly be mediated by EGF.     

Transforming growth factor beta and platelet-derived growth factor in human myometrium and in uterine leiomyomas at various stages of tumour growth

OBJECTIVE: Some authors suggest that growth factors are intermediate regulatory elements through which the ovarian hormones exert their growth-stimulatory effects on uterine leiomyomas. STUDY DESIGN: It was decided to compare the amounts of transforming growth factor beta (TGF-beta) and platelet-derived growth factor (PDGF) in myometrium and in uterine leiomyomas of various weights (small: less than 10 g and large: more than 100 g). The tissues were homogenised and extracted with 1M acetic acid or with 0.05 M Tris-HCl, pH 7.6. The extracts were assayed for TGF-beta and PDGF with the use of the ELISA technique. RESULTS: The Tris-HCl was more efficient at extracting solvent than 1M of acetic acid. Both myometrium and leiomyomas contained nanogram amounts of extractable TGF-beta and picogram amounts of PDGF. Western immunoblotting demonstrated that both factors exist as stable complexes, probably with extracellular matrix components. The PDGF/TGF-beta ratio in Tris-HCl extracts was higher in leiomyomas than in myometrium and it increased during tumour growth. CONCLUSION: It is known that low concentrations of TGF-beta induce proliferation of cells by stimulating autocrine PDGF secretion. Higher concentrations of TGF-beta1 evoke a reverse effect by the down-regulation of the PDGF receptor and by direct growth inhibition. The increase in the PDGF/TGF-beta ratio during tumour growth seems be important in tumour biology. The low amount of TGF-beta eliminates the inhibitory effect of this factor on cell proliferation and stimulates both autocrine PDGF secretion and promotes the synthesis of PDGF receptors. It is thus possible to bind more PDGF by myometrial cells resulting in a hyperplasia of myometrium and enhancement of extracellular matrix synthesis.     

Estradiol and progesterone binding in uterine leiomyomata and pregnant myometrium

In order to verify the endogenous steroid influences on the myometrium, we compared the receptor status in 18 specimens of uterine leiomyomata and 31 specimens of pregnant myometrium. 17-beta-Estradiol and Progesterone receptors were assayed in the cytosol and nuclear extracts. In the uterine leiomyomata we observed the following mean values: PgR/c 279 fmol/mg, PgR/n 89 fmol/mg, ER/c 52.5 fmol/mg, ER/n 12.3 fmol/mg. In the pregnant myometrium we observed the following mean values: PgR/c 5.86 fmol/mg, PgR/n 166 fmol/mg, ER/c 0.76 fmol/mg, ER/n 1.65. It was concluded that direct correlation between estrogen power and progesterone receptor replenishment in the nucleus exists.     

Progesterone-induced secretion of growth hormone, insulin-like growth factor I and prolactin by human breast cancer explants.

The aim of the study was to evaluate the potential of human breast cancer tissue to secrete growth hormone (GH), insulin-like growth factor I (IGF-I) and prolactin in response to 10(-7) M progesterone stimulation. Explants were divided according to estrogen receptor (ER)/progesterone receptor (PR) phenotype (ER(-)PR(-); ER(+)PR(-); ER(+)PR(+); ER(-)PR(+)). Our results show distinct differences in cultured breast cancer tissue responses to progesterone stimulation with regard to secretion of proliferative agents such as GH, IGF-I and prolactin. All but ER(-)PR(-) breast cancer cell types responded in vitro to progesterone stimulation with an increase in local GH secretion, while in non-malignant tissue progesterone induced local GH secretion only in PR(+) cells. Moreover, only in PR(+) cells did progesterone stimulate local IGF-I and prolactin secretion, in both malignant and non-malignant tissue. This study provides evidence for the first time that in PR(+) breast cancer tissue, progesterone may increase GH, prolactin and IGF-I secretion in both malignant and surrounding non-malignant tissue. These hormones may act as local growth factors that stimulate the proliferation of mammary tumors.     

A potential role for epidermal growth factor/alpha-transforming growth factor in human parturition

Epidermal growth factor (EGF)/alpha-transforming growth factor (alpha-TGF) concentrations were measured in amniotic fluid by radioreceptor assay in non-laboring and laboring patients at term. The median concentrations of EGF/alpha-TGF were 1.28 ng/ml and 5.0 ng/ml in non-laboring and laboring patients respectively (p less than 0.05, Wilcoxon test). EGF was then incubated with amnion cells in monolayer culture to ascertain the effect of this hormone on the release of prostaglandin E2. Experiments were carried out in quadruplicate in 11 separate primary amnion-cell cultures (EGF was used at 1 ng/ml and 5 ng/ml, respectively). An increased release of prostaglandin E2 into the media was found. The response was concentration-dependent (p less than 0.01). We suggest that there may be a role for EGF in the mechanism of human parturition.     

胰岛素样生长因子Ⅰ及胰岛素与胎儿宫内发育迟缓发病的关系

目的 探讨胰岛素样生长因子１（ＩＧＦ－Ｉ）及胰岛素与胎儿宫内发育迟缓（ＩＵＧＲ）发病的关系。方法 应用放射免疫分析法和酶联免疫吸附试验,分别测定１７例ＩＵＧＲ患儿,孕妇（ＩＵＧＲ组）血清及羊水中Ｉｎｓ和ＩＧＦ－Ｉ水平,同期住院的正常晚期妊娠妇女３８例（正常妊娠组）作为对照。     

The expression of insulin-like growth factor and insulin-like growth factor binding protein mRNAs in mouse placenta

Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) are paracrine regulators of tissue growth and development, and are expressed at the sites of biological action. To study the role of the IGFs and IGFBPs in mouse placental development, we determined the temporal and spatial expression patterns of the mRNAs at embryonic days 10.5 to 18.5 by in situ hybridization. IGF-II mRNA was expressed strongly in mesoderm and fetal blood vessels of early placenta and in labyrinthine trophoblast of later placenta. In the junctional zone, IGF-II mRNA was expressed first in spongiotrophoblasts, later strongly in glycogen cells and variably in giant cells. IGFBP-2 mRNA was expressed weakly in spongiotrophoblasts and glycogen cells. IGFBP-2, -5 and -6 mRNAs were detected in the stroma of the metrial gland. Myometrium expressed IGFBP-2 mRNA strongly, IGFBP-6 mRNA moderately and IGFBP-5 mRNA weakly. The endothelium of maternal blood vessels in decidua expressed IGFBP-3 and -5 mRNAs, and some deeper vessels expressed IGFBP-4 mRNA. In the yolk sac, IGF-II mRNA was expressed in endoderm and mesoderm, whereas IGFBP-1, -2 and -4 mRNAs were expressed only in endoderm, and IGFBP-4 mRNA in mesoderm. Strong expression of IGF-II mRNA in glycogen cells suggests a role in the autocrine/paracrine regulation of invasion. Similar to rat and guinea pig, but in contrast to man and primates, IGFBP mRNAs, except IGFBP-4, were not expressed in mouse decidua. However, IGFBP-3, -4 and -5 mRNAs were expressed in endothelium of maternal blood vessels, and IGFBP-2 and -6 mRNAs in myometrium, where IGFBPs may play a critical role in regulating trophoblast invasion. These findings suggest possible biological roles of the peptides at the feto-maternal interface.     

Expression of transforming growth factor-alpha, epidermal growth factor, and epidermal growth factor receptor in follicles of human ovarian tissue before and after cryopreservation

OBJECTIVE: To study the expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), and EGF receptor in follicles of human ovarian tissue. DESIGN: A retrospective, controlled comparative study. SETTING: In vitro fertilization laboratory of a university hospital. PATIENT(S): Fifteen women with regular menstrual cycles who underwent laparoscopy and the biopsy of ovarian tissue. INTERVENTION(S): Paraffin sections were prepared from ovarian tissues, followed by immunohistochemical staining of TGF-alpha, EGF, and EGF receptor. MAIN OUTCOME MEASURE(S): Immunostaining for TGF-alpha, EGF, and EGF receptor in follicles of fresh and frozen ovarian tissues. RESULT(S): Immunoreactivities for TGF-alpha and EGF receptor were observed simultaneously in the oocytes of primordial, primary, preantral, and antral follicles. Strong staining for TGF-alpha and EGF receptor was present in thecal cells. The TGF-alpha and EGF receptor was also expressed in some granulosa cells of primary to antral follicles. The EGF only stained weakly in the oocytes of primordial and primary follicles and in thecal cells. There was no difference in staining patterns for TGF-alpha, EGF, and EGF receptor between fresh and frozen ovarian tissues. CONCLUSION(S): The TGF-alpha and EGF receptor was expressed in primordial to antral follicles, indicating a role of TGF-alpha in regulating follicular development through binding to the EGF receptor. Freeze-thawing did not substantially alter immunoreactivites for TGF-alpha, EGF, and EGF receptor in frozen ovarian tissue.