Human Endometrial Glandular Cells Research Articles

Expression of cell adhesion molecule 1 in human and murine endometrial glandular cells and its increase during the proliferative phase by estrogen and cell density

AimsCell adhesion molecule 1 (CADM1) mediates interepithelial adhesion and is upregulated in crowded epithelial monolayers. This study aimed to examine CADM1 expression in the human endometrium of proliferative and secretory phases, and its transcriptional regulation in terms of estrogen stimuli and higher cellularity. Main methodsCADM1 immunohistochemistry was conducted on endometrial tissues from women in their 40s and adult mice subcutaneously injected with estradiol following ovariectomy. Dual-luciferase reporter assays were conducted using human endometrial HEC-50B and HEC-1B cells and reporter plasmids harboring the human CADM1 3.4-kb promoter and its deleted and mutated forms. Cells were transfected with estrogen receptor α cDNA and reporter plasmids, and treated with estradiol before luciferase activity measurement. Key findingsImmunohistochemistry revealed that CADM1 was clearly expressed on the lateral membranes of the simple columnar glandular cells in the proliferative phase, but not in the secretory phase, from both women and the mouse model. The glandular cell density increased two-fold in the proliferative phase. Reporter assays identified three Sp1-binding sites as estradiol-responsive elements in the proximal region (from −223 to −84) of the transcription start site (+1) in HEC-50B cells. When the cell culture was started at eight-fold higher cell density, the CADM1 3.4-kb promoter was transactivated at a two-fold higher level in HEC-50B cells. This cell density effect was not detected for the CADM1 2.3-kb or 1.6-kb promoter. SignificanceTwo (proximal and distal) promoter regions are suggested to function additively to transactivate CADM1 in endometrial glandular cells that crowd in the proliferative phase.

Growth hormone promotes human endometrial glandular cells proliferation and motion through the GHR-STAT3/5 pathway.

This study aims at investigating the effect of growth hormone (GH) on the growth of human endometrial glandular cells (hEGCs) and preliminary exploring its mechanism. HEGCs were isolated from the endometrial biopsies and exposed to different dose of GH (0, 50, 100, and 200 ng/mL). Cell proliferation and cell cycle assay, migration assay was performed to investigate the growth and motivation of hEGCs, respectively. Reverse transcription-polymerase chain reaction (RT-PCR), immunocytochemistry (ICC), and western blot (WB) were processed to investigate its related gene or protein expression. The results revealed that GH administration promoted the proliferation, cell cycle, migration, and growth hormone receptors (GHRs) expression of the hEGC. We further inhibited GHRs with AG490, and the inhibitor reversed the effects of GH on cell growth, motion, and the activation of GHR and STAT3/5. GH promoted hEGCs proliferation and motion, which is GHR-JAK-STAT3/5 signaling pathway-dependent. These findings reveal the essential roles of GH in the hEGCs growth and provide evidence for potential GH therapy in intrauterine adhesion (IUA) treatment.

The effects and mechanisms of GM-CSF on endometrial regeneration

BackgroundEndometrial injury can result in thin endometrium and subfertility. Granulocyte macrophage colony stimulating factor (GM-CSF) contributes to tissue repair, but its role in endometrial regeneration has not been investigated. MethodsTo determine the effect of GM-CSF on endometrial regeneration, we established a mouse model of thin endometrium by uterine perfusion with 20 μL 90% ethanol. Thin endometrium in mice was featured by lowered endometrial thickness, decreased expression of Ki67 in glandular cells, and a reduced number of implantation sites. To explore the mechanism of GM-CSF on endometrial regeneration, endometrium was obtained from patients undergoing hysterectomy or hysteroscopy and endometrial biopsy. Effects of GM-CSF on primary cultured human endometrial glandular and stromal cells were examined by the 5-bromo-2′-deoxyuridine (BrdU) proliferation assay and transwell migration assay, followed by exploration of the potential signaling pathway. ResultsGM-CSF intraperitoneal (i.p.) injection significantly increased endometrial thickness, expression of Ki67 in endometrial glandular cells, and the number of implantation sites. GM-CSF significantly promoted proliferation of primary human endometrial glandular cells and migration of stromal cells. GM-CSF activated p-Akt and increased expressions of p70S6K and c-Jun, which were blocked by LY294002. ConclusionWe found that GM-CSF could improve endometrial regeneration, possibly through activating PI3K/Akt signaling pathway.

Effects of the Diaomo-Zhibeng liquid on the expression of Bcl-2/Bax mRNA and their protein in vitro human endometrial glandular epithelial cells

Objective To observe the effects of the Diaomo-Zhibeng liquid on the expression of Bcl-2/Bax mRNA and their protein in vitro endometrial glandular epithelial cells in patients of endometrial hyperplasia Methods The endometrial tissue in patients with the pathological diagnosis of endometrial hyperplasia were collected. After isolation, culture and identification, the endometrial cells were divided into four groups: low dosage group(12.5 μg/ml), middle dosage group(25 μg/ml), high dosage group(50 μg/ml) and blank control group at randomaccording to the random number table. Three duplicate samples were set for each group. After 48h, the expression of Bcl-2 and Bax were detected by RT-PCR and Western-blot. Results Compared with the blank control group, the expression of Bcl-2 mRNA (1.51 ± 0.07, 1.09 ± 0.06, 0.93 ± 0.07 vs. 1.92 ± 0.08) and protein (0.91 ± 0.02, 0.72 ± 0.03, 0.62 ± 0.03 vs. 1.28 ± 0.02) significantly decreased, while the expression of Bax mRNA (5.73 ± 0.37, 8.00 ± 0.23, 10.72 ± 0.40 vs. 3.27 ± 0.34) and protein (0.45 ± 0.02, 0.63 ± 0.02, 0.78 ± 0.03 vs. 0.32 ± 0.02) sifnificantly promoted in low dosage group, medium dosage group and high dosage group of Diaomo-Zhibeng liquid (P<0.05). Compared with low dosage group, the expression of Bcl-2 mRNA and protein significantly decreased in middle and high dose group (P<0.05), but Bax mRNA and protein significantly increased (P<0.05). Conclusions The Diaomo-Zhibeng liquid can increase the susceptibility of epithelial cells to apoptosis, regulate the balance of cell proliferation and apoptosis tends to apoptosis, have the effect of accelerating cells apoptosis. Key words: Endometrial hyperplasia; Apoptosis; Genes, bcl-2; bcl-2-Associated X protein; Diaomo-Zhibeng Liquid

Isoflavone increases the mRNA expression levels of IL-6 signal transducer glycoprotein 130 in human endometrial glandular cells

Isoflavone increases the mRNA expression levels of IL-6 signal transducer glycoprotein 130 in human endometrial glandular cells

Isoflavone increases the mRNA expression levels of IL-6 signal transducer glycoprotein 130 in human endometrial glandular cells

Isoflavone increases the mRNA expression levels of IL-6 signal transducer glycoprotein 130 in human endometrial glandular cells

Isoflavone increases the mRNA expression levels of IL-6 signal transducer glycoprotein 130 in human endometrial glandular cells

Purpose of investigation: The authors examined whether isoflavone can effectively increase the secretion of cytokines associated with implantation from endometrial glandular cells. Material and Methods: Endometrial tissue was collected from 14 patients who underwent surgery for benign gynecological diseases in this hospital. The endometrial tissue was separated into stromal and glandular cells, and isoflavone was added to the glandular cells at a concentration of 0, 0.05, 0.5, and 5 &#x03BC;g/ml. In another group, an estrogen receptor antagonist was added together with isoflavone. After 24 hours, the expression levels of leukemia inhibitory factor, interleukin (IL)-6, IL-11, and IL-6 signal transducer glycoprotein 130 (IL-6/gp130) were measured by quantitative polymerase chain reaction. Results: A significant increase in the expression of IL-6/gp130 was found in glandular cells treated with isoflavone (0.5 &#x03BC;g/ml). The significant differences were not observed among the groups upon treatment with isoflavone and an estrogen receptor antagonist, indicating that isoflavone acted via the estrogen receptor. Conclusion: Isoflavone increases the mRNA expression levels of IL-6/gp130 in human endometrial glandular cells of early to mid secretary phase.

Divergent endometrial inflammatory cytokine expression at peri-implantation period and after the stimulation by copper intrauterine device.

Endometrial inflammation has contradictory effects. The one occurring at peri-implantation period is favourable for embryo implantation, whereas the other occurring after the stimulation by copper intrauterine device (Cu-IUD) prevents from embryo implantation. In this study, 8 week female ICR mice were used to investigate the endometrial inflammation, in which they were at proestrus stage (Group 1), at peri-implantation period (Group 2), and had a copper wire implanted into right uterine horn (Group 3). Cytokine array revealed that two cytokines were highly expressed in Group 2 and Group 3 as compared with Group 1, and seven cytokines, including tumour necrosis factor α (TNF-α), had selectively strong expression in Group 3. Immunohistochemistry demonstrated prominent TNF-α staining on the endometrium after Cu-IUD stimulation, and in vitro culture of human endometrial glandular cells with Cu induced TNF-α secretion. The increased TNF-α concentration enhanced in vitro THP-1 cells chemotaxis, and reduced embryo implantation rates. These results suggest that inflammatory cytokine profiles of endometrium are different between those at peri-implantation period and after Cu-IUD stimulation, and TNF-α is the one with selectively strong expression in the latter. It might account for the contradictory biological effects of endometrial inflammation.

Levonorgestrel Inhibits Human Endometrial Cell Proliferation through the Upregulation of Gap Junctional Intercellular Communication via the Nuclear Translocation of Ser255 Phosphorylated Cx43.

Objects. To assess whether LNG exerts antiproliferation effects on human endometrial cells through changes of GJIC function and the phosphorylated Cx43. Methods. Cell proliferation and apoptosis of human endometrial stromal cells (HESCs) and glandular cells (HEGCs) treated with LNG in a dose- and time-dependent manner. GJIC change and further total Cx43 and serine 368 and 255 phosphorylated Cx43 were measured. Results. 5 × 10−5 mol/L LNG revealed a time-dependent inhibition of cell proliferation and an increase of apoptosis in both HESCs and HEGCs. Furthermore, these cells demonstrated a significant GJIC enhancement upon treatment with 5 × 10−5 mol/L for 48 hours. The effects of LNG were most noticeable in HESCs rather than in HEGCs. Associated with these changes, LNG induced a relative increase in total Cx43 in a time-dependent manner but not Ser368 phosphorylated Cx43. Moreover, laser scanning confocal microscope confirmed the increased expression of total Cx43 in the cytoplasm and, interestingly, the nuclear translocation of Ser255 phosphorylated Cx43. Conclusions. LNG likely inhibits the proliferation and promotes apoptosis in HESCs and HEGCs though an increase in gap junction permeability in vitro, which is achieved through the upregulation of Cx43 expression and the translocation of serine 255 phosphorylated Cx43 from the plasma to the nuclear compartment.

EPAC2-mediated calreticulin regulates LIF and COX2 expression in human endometrial glandular cells.

The proper production of the implantation-related factors, leukemia inhibitory factor (LIF), cyclooxygenase 2 (COX2, PTGS2), and prostaglandin E2 (PGE2) in the uterine glands is essential for embryo implantation and the establishment of endometrial receptivity. It has been shown that cAMP-mediated protein kinase A (PKA) signaling regulates the production of these factors. We have previously reported that exchange protein directly activated by cAMP 2 (EPAC2, RAPGEF4), another cAMP mediator, is involved in the differentiation of endometrial stromal cells through the regulation of the expression of calreticulin (CALR). To address whether EPAC2-CALR signaling is involved in the expression of implantation-related factors, we examined the effect of EPAC2 and CALR knockdown on their expression in cultured human endometrial glandular epithelial EM1 cells, treated with forskolin, an adenylyl cyclase activator, an EPAC-selective cAMP analog (8-(4-chlorophenylthio)-2'-O-methyl cAMP (CPT)), or a PKA-selective cAMP analog (N(6)-phenyl-cAMP (Phe)). In addition, the status of cell senescence was examined. EPAC2 knockdown suppressed the expression of CALR protein and mRNA in EM1 cells. Forskolin- or Phe-, but not CPT-, induced expression of LIF or PTGS2 and secretion of PGE2 was inhibited in EPAC2- or CALR-silenced EM1 cells. In addition, knockdown of EPAC2 or CALR increased senescence-associated beta galactosidase activity and expression of p21 but decreased expression of p53. These findings indicate that expression of CALR regulated by EPAC2 in endometrial glandular epithelial cells is critical for the expression of LIF and PTGS2-mediated production of PGE2 through cAMP signaling. Furthermore, EPAC2 and CALR could play a role in the maintenance of gland function.

Bidirectional Interaction Between Unfolded-Protein-Response Key Protein HSPA5 and Estrogen Signaling in Human Endometrium1

The human endometrium is a dynamic tissue that undergoes cyclic changes under the influence of steroid hormones as well as numerous local paracrine and autocrine factors. Heat shock 70 kDa protein (HSPA5; also known as GRP78/BiP), a molecular chaperone within the endoplasmic reticulum, plays crucial roles in normal cellular processes as well as in stress conditions, in which it is a central regulator for the unfolded protein response (UPR). We hypothesized that HSPA5 expression level is variable throughout the menstrual cycle in human endometrium and that estrogen signaling cross-talks with UPR signaling by interacting with HSPA5. HSPA5 expression throughout the menstrual cycle was evaluated in vivo in normal human endometrium. Using in vitro techniques, we then assessed the bidirectional regulation of HSPA5 and estrogen signaling in human endometrial glandular (Ishikawa) and stromal cells (ESC). HSPA5 immunoreactivity in endometrial glandular and stromal cells was cycle-dependent, and was significantly higher in phases of the menstrual cycle when estradiol (E(2)) levels are known to be the lowest compared with the rest of the cycle (P < 0.001). E(2) did not affect HSPA5 expression after 8-24 h incubation in Ishikawa cells and ESC in vitro. However, tunicamycin-induced HSPA5 expression was significantly lowered in these cells when pretreated with E(2) (P < 0.01 and P < 0.05, respectively). On the other hand, tunicamycin decreased E(2) up-regulated alkaline phosphatase activity (P < 0.001). In conclusion, there is cycle-dependent HSPA5 expression with a possible inverse correlation between HSPA5 expression and E(2) levels in human endometrium. We suggest that estrogen signaling cross-talks with the UPR cascade by interacting with HSPA5, as supported by our in vitro findings.

Effect of TNF-α on Estrogen Metabolism and Endometrial Cells: Potential Physiological and Pathological Relevance

Context: Estrogen and its metabolites play a critical role in the pathophysiology of the endometrium. The bioavailability of estrogen and estrogen metabolites in endometrial tissues depends on the expression of enzymes involved in estrogen biosynthesis and metabolism. Substantial evidence indicates that estrogen-dependent endometrial disorders are also associated with proinflammatory milieu. However, the mechanism whereby inflammation contributes to these conditions is not known. Objective: Investigate the effect of the tumor necrosis factor(TNF) on estrogen metabolism and on the expression of estrogen-metabolizing genes in human endometrial glandular epithelial cells (EM1). Design: EM1 were treated with 17 -estradiol (E2) with or without TNF. Capillary liquid chromatography-tandem mass spectrometry analysis was used for quantitative measurement of estrogens and estrogen metabolites. Western blot analysis, reporter gene assay, and real time RT-PCR were used to assess the expression of estrogen-metabolizing genes. Results: TNFtreatment significantly increased the level of total estrogen and estrogen metabolites and significantly increased the rate of conversion of estrone (E1) into E2. TNFalso enhanced the oxidative metabolism of estrogen into catecholestrogens with concomitant inhibition of their conversion into methoxyestrogens. Gene expression analysis revealed that TNFinduced the expression of genes involved in E2 biosynthesis (SF-1 and CYP19) and activation (HSD17B1 and CYP1B1) with simultaneous repression of genes involved in estrogen inactivation (HSD17B2; COMT; and NQO1). Conclusion: TNFincreases the local estrogen biosynthesis in human endometrial glandular cells and directs estrogen metabolism into more hormonally active and carcinogenic metabolites. These effects may impact many physiological and pathological processes that occur within endometrium. Glucocorticoid Receptor Gene Variant in the 3 Untranslated Region Is Associated with Multiple Measures of Blood Pressure Charles C. Chung, Lawrence Shimmin, Sivamani Natarajan, Craig L. Hanis, Eric Boerwinkle, and James E. Hixson (J. Clin. Endocrinol. Metab., published October 14, 2008, 10.1210/jc.2008-1089) ABSTRACT Context: The glucocorticoid receptor (GR) is a key hormone in the hypothalamus-pituitary-adrenal axis that regulates many pathways including blood pressure homeostasis. Thus, GR gene variation may influence interindividual differences in blood pressure in human populations. Objective: We resequenced individual GR alleles for comprehensive discovery of GR variants and their chromosomal phase in three major American ethnic groups. We examined the influence of GR variants on blood pressure in large numbers of families using family-based association methods. Design and Participants: For association studies, we genotyped GR variants in family members from the GENOA study that were measured for multiple blood pressure traits. The GENOA families consisted of African Americans, Mexican Americans, and European Americans. Main Measurements: The blood pressure measurements for association studies included systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP). T R A N S L A T I O N A L H I G H L I G H T S F R O M J C E MContext: The glucocorticoid receptor (GR) is a key hormone in the hypothalamus-pituitary-adrenal axis that regulates many pathways including blood pressure homeostasis. Thus, GR gene variation may influence interindividual differences in blood pressure in human populations. Objective: We resequenced individual GR alleles for comprehensive discovery of GR variants and their chromosomal phase in three major American ethnic groups. We examined the influence of GR variants on blood pressure in large numbers of families using family-based association methods. Design and Participants: For association studies, we genotyped GR variants in family members from the GENOA study that were measured for multiple blood pressure traits. The GENOA families consisted of African Americans, Mexican Americans, and European Americans. Main Measurements: The blood pressure measurements for association studies included systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP). T R A N S L A T I O N A L H I G H L I G H T S F R O M J C E M

Effect of Tumor Necrosis Factor-α on Estrogen Metabolism and Endometrial Cells: Potential Physiological and Pathological Relevance

Estrogen and its metabolites play a critical role in the pathophysiology of the endometrium. The bioavailability of estrogen and estrogen metabolites in endometrial tissues depends on the expression of enzymes involved in estrogen biosynthesis and metabolism. Substantial evidence indicates that estrogen-dependent endometrial disorders are also associated with proinflammatory milieu. However, the mechanism whereby inflammation contributes to these conditions is not known. The objective of the study was to investigate the effect of TNF-alpha on estrogen metabolism and the expression of estrogen-metabolizing genes in human endometrial glandular epithelial cells (EM1). EM1 were treated with 17beta-estradiol (E2) with or without TNF-alpha. Capillary liquid chromatography-tandem mass spectrometry analysis was used for quantitative measurement of estrogens and estrogen metabolites. Western blot analysis, reporter gene assay, and real-time RT-PCR were used to assess the expression of estrogen-metabolizing genes. TNF-alpha treatment significantly increased the level of total estrogen and estrogen metabolites and significantly increased the rate of conversion of estrone (E1) into E2. TNF-alpha also enhanced the oxidative metabolism of estrogen into catecholestrogens with concomitant inhibition of their conversion into methoxyestrogens. Gene expression analysis revealed that TNF-alpha induced the expression of genes involved in E2 biosynthesis (steroidogenic factor-1 and aromatase) and activation (17beta- hydroxysteroid dehydrogenase type 1 and cytochrome P-450, 1B1) with simultaneous repression of genes involved in estrogen inactivation (17beta-hydroxysteroid dehydrogenase type 2; catechol O-methyltransferase; and nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1). TNF-alpha increases the local estrogen biosynthesis in human endometrial glandular cells and directs estrogen metabolism into more hormonally active and carcinogenic metabolites. These effects may impact many physiological and pathological processes that occur within the endometrium.

Catecholestrogens induce oxidative stress and malignant transformation in human endometrial glandular cells: Protective effect of catechol‐O‐methyltransferase

Prolonged exposure to unopposed estrogens is a major risk factor for the development of endometrial cancer. Oxidative metabolism of estradiol (E(2)) into the catecholestrogens (CEs), 4-hydroxyestradiol (4-OHE(2)) and 2-hydroxyestradiol (2-OHE(2)), may play an important role in estrogen carcinogenicity. CEs can be oxidized to the corresponding ortho-quinone derivatives with concomitant formation of the reactive oxygen species (ROS). Catechol-O-methyltransferase (COMT) is the major enzyme involved in the detoxification of CEs in extrahepatic tissues. We investigated the potential of E(2), 2-OHE(2) and 4-OHE(2) to induce microsatellite instability (MSI) and neoplastic transformation of immortalized human endometrial glandular (EM) cells. We also investigated the functional significance of COMT gene expression on modulating the effects of E(2) and CEs in EM cells. Our data indicated that E(2) and 4-OHE(2) induce MSI, ROS and neoplastic transformation in EM cells. The capacity of E(2) and its catechol metabolites to induce MSI, ROS and neoplastic transformation in EM cells is ranked as follows: 4-OHE(2) > E(2) > 2-OHE(2). Knockdown of COMT expression in EM cells resulted in increased estrogenic milieu and increased estrogen-induced cell proliferation. More importantly, knockdown of COMT increased the propensity of E(2) or CEs to induce ROS, MSI and neoplastic transformation of EM cells. In contrast, overexpression of COMT in EM cells significantly reduced the cellular estrogenic milieu and protected against E(2)- or CEs-induced, ROS, MSI and neoplastic transformation. The capacity of E(2) or CEs to induce neoplastic transformation of human endometrial glandular cells in vitro may suggest that E(2)-induced endometrial cancer is mediated by its metabolism into CEs. Our study clearly indicates that COMT gene expression plays a critical role in modulating the hormonal and carcinogenic effects of E(2) and CEs and, consequently, modifies the risk for E(2)-induced endometrial cancer. To the best of our knowledge, this is the first study to (i) demonstrate the potential capacity of estrogen and its catechol metabolites to induce neoplastic transformation of immortalized human endometrial glandular cells; and (ii) illustrate the important role of COMT gene expression in protecting against E(2)-induced endometrial cancer.

Application of laser capture microdissection and differential display technique for screening of pathogenic genes involved in endometrial carcinoma

The objective is to eliminate the interference from other cell types; gene fragments involved in endometrial carcinoma (EC) are screened and cloned. Human normal endometrial glandular epithelia and EC cells were harvested with laser capture microdissection (LCM). The purification and concentration of minimal RNA were used to screen differential expressed gene fragments involved in EC by fluoro differential display polymerase chain reaction (FDD-PCR). The differential gene fragments were cloned, sequenced, and then identified by reverse Northern blot hybridization. Positive fragments were analyzed with basic local alignment search tool (BLAST). Cyclin-dependent kinase 7 (CDK7) expressions in EC and normal endometrial tissue were tested by immunohistochemical staining. Of 38 differential bands, 3 bands were of high expression in normal endometrium and 35 in EC. Six positive differential gene fragments were obtained and BLAST analysis for them suggested that L1.1 was homologous (99% identical) to the CDK7; L1.9 had a 99% homology with protein phosphatase 1 regulatory (inhibitor) subunit 12 A (PPP1R12A); L1.21 and L1.22 showed a 100% homology with cellular repressor of E1A-stimulated genes 1 (CREG); and L1.25 and L1.26 indicated more than 98% homology with solute carrier family 39 (zinc transporter), member 10 (SLC39A10). Immunohistochemistry revealed that CDK7 expression was higher in EC than in normal endometrium. We conclude that pathogenic genes involved in EC are obtained with LCM and FDD-PCR. It has been first found that CDK7, PPP1R12A, CREG, and SLC39A10 are correlative with EC from gene level. CDK7 is strongly associated with EC and can be used as potential molecular marker of EC for further studies.

Progestagenic Effects of Tibolone are Target Gene—Specific In Human Endometrial Cells

Tibolone (Tib) exhibits progestagenic activities in addition to its tissue-specific estrogenic activities. The purpose of the current study was to determine the progestagenic actions of Tib and its metabolites using target genes known to be regulated by progestins in human endometrial glandular and stromal cells. Human endometrial glandular and stromal cells were isolated from endometrial tissue fragments and separately incubated with Tib and its metabolites. Real-time polymerase chain reaction (PCR) was used to determine the mRNA content of 17betahydroxy steroid dehydrogenase (17betaHSD, type 2) and sulfotransferase (SULT1E1) in endometrial glandular cells, and prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP1) in endometrial stromal cells. In glandular cells, Tib and Delta4-tibolone (Delta4Tib) significantly increased the content of 17betaHSD and SULT1E1 mRNA. In stromal cells, Tib and Delta4Tib increased PRL mRNA ( approximately 30% of the capacity compared to progesterone) and had little effect on IGFBP1 mRNA. Anti-progestin, RU486, reversed the induction of SULT1E1 and PRL by progesterone or Tib. Also, the two 3 hydroxyl tobolone metabolites, especially 3betaOHTib, showed some progestagenic effects. The data showed that Tib and Delta4Tib exhibited clear progestagenic effects in endometrial glandular cells by inducing 17betaHSD and SULT1E1, while in stromal cells the response was weaker in the induction of PRL and had little effect on IGFBP1. In addition, the 3betaOHTib metabolite expressed progestagenic activity. These disparate effects in two types of cells may be beneficial for maintaining endometrial cells in a quiescent state.

Successful Immortalization of Endometrial Glandular Cells with Normal Structural and Functional Characteristics

The human endometrium is a dynamic tissue, the proliferative activity of which dramatically changes throughout the menstrual cycle, with exquisite regulation by sex-steroid hormones. Primary endometrial epithelial cells fall into senescence within 2 weeks when cultured on plastic dishes, and more complete understanding of endometrial biology has been delayed because of, in part, a lack of an in vitro culture model for endometrial epithelial cells. Our goal was to establish immortalized human endometrial glandular cells that retain the normal functions and characteristics of the primary cells. Because the Rb/p16 and p53 pathways are known to be critical elements of epithelial senescence in early passages, we used human papillomavirus E6/E7 to target these pathways. The combination of human papillomavirus-16 E6/E7 expression and telomerase activation by the introduction of human telomerase reverse transcriptase (hTERT) led to successful immortalization of the endometrial glandular cells. E6/E7 expression alone was sufficient to extend their life span more than 20 population doublings, but the telomerase activation was further required to enable the cells to pass through the subsequent replicative senescence at 40 population doublings. Isolated immortalized cells contained no chromosomal abnormalities or only nonclonal aberrations, retained responsiveness to sex-steroid hormones, exhibited glandular structure on three-dimensional culture, and lacked transformed phenotypes on soft agar or in nude mice. These findings support the notion that both Rb inactivation/p53 inactivation and telomerase activation are necessary to immortalize endometrial epithelial cells, but additional factors are required for endometrial carcinogenesis. Our established cell lines show great promise for investigation of hormone functions, endometrial biology, and endometrial carcinogenesis.

Immunohistochemical expression of inhibin-alpha in human endometrium and the in vitro secretion of inhibin, estradiol and cortisol in cultured human endometrial glandular cells.

Inhibins are multipotent dimeric glycoproteins, composed of an alpha-subunit and one of two possible beta-subunits (betaA or betaB). Aims of this study were (a): the immunohistochemical characterisation of normal human endometrium for the inhibin-alpha subunit; (b) the assessment of the secretion and metabolism of inhibin, E2 and cortisol; (c) the evaluation of any relationship between these three substances in cell culture medium of isolated and cultivated normal human endometrial glandular cells. Samples of human endometrium were obtained from 34 premenopausal patients. Nineteen endometrial specimen (proliferative [PP] n=8; early secretory [ES] n=7; late secretory phase [LS] n=4) were brought into cell culture. Fifteen endometrial specimen (PP n=5; ES n=5; LS n=5) were paraffin-fixed and used for the immunohistochemical analysis for inhibin-alpha. Stromal and epithelial cells were separated by collagenase digestions, filtrations, sedimentations and Ficoll-gradient centrifugation. E2 and cortisol were measured with radioimmunoassay (RIA) and inhibin with enzyme-immunoassay (EIA). Statistical analysis was performed with the non-parametric Mann-Whitney rank-sum test and linear regression analysis. Inhibin-alpha showed a weak (positive) expression during proliferative phase, which increased significantly as the menstrual cycle continued. In secretory glands the mean inhibin concentration was higher than that from proliferative samples. A significant correlation was observed between inhibin and E2 (p<0.001) as well as cortisol and inhibin (p<0.0001) in glands from proliferative phase. Between inhibin and E2 (p<0.05) as well as inhibin and cortisol (p<0.002) a significant correlation in early secretory glands was also noted. In late secretory phase inhibin and E2 (r2=0.78650; p<0.0001), inhibin and cortisol (r2=0.58326; p<0.001) and E2 and cortisol (r2=0.52880; p<0.001) showed a significant correlation. In conclusion, we found a cyclical expression of inhibin-alpha subunit in the endometrium demonstrated by immunohistochemical means. A higher in vitro secretion of inhibin from secretory glands was also observed. In addition, a significant correlation between inhibin with E2 and cortisol in PP and ES glands and a significant correlation between inhibin, E2 and cortisol in LS glands could also be demonstrated. We conclude that inhibin can be associated with E2 and cortisol metabolism, playing an important role in paracrine/autocrine mechanisms in the endometrium and possibly exerting its function through cortisol and E2. The cortisol concentration also correlates with E2, suggesting a link between these steroids in the endometrial function. The correlation of inhibin, E2 and cortisol suggest complex autocrine/ paracrine mechanisms in human endometrial glands, modulated and controlled by all these three substances.

Up-Regulation of p27Kip1 by Progestins Is Involved in the Growth Suppression of the Normal and Malignant Human Endometrial Glandular Cells

Up-Regulation of p27Kip1 by Progestins Is Involved in the Growth Suppression of the Normal and Malignant Human Endometrial Glandular Cells

Up-regulation of p27Kip1 by progestins is involved in the growth suppression of the normal and malignant human endometrial glandular cells.

Progestins are known to suppress the growth of normal human endometrial glands and endometrial carcinomas possessing PRs. To elucidate the molecular mechanisms of progestin-induced growth inhibition, the expression and functional involvement of p27Kip1 (p27), a cyclin-dependent-kinase inhibitor, was investigated using cultured normal endometrial glandular cells and endometrial carcinoma cell lines (Ishikawa; PR-positive, KLE; PR-negative). Growth of the normal endometrial glandular cells and Ishikawa cells was suppressed by treatment with progesterone and medroxyprogesterone acetate, respectively, in association with an increase in p27 protein expression. Immunoprecipitation revealed that progestins accelerated the complex formation of p27 and cdk2 in both types of cells. However, treatment with progestins did not show any marked alterations in the mRNA expression of p27 in either normal glandular cells or Ishikawa cells. On the other hand, p27 protein degradation experiments indicated that treatment with progesterone and medroxyprogesterone acetate prolonged the degradation time of the normal endometrial glandular cells and Ishikawa cells, respectively. Forced expression of the p27 protein using a p27 expression plasmid reduced the growth activity of normal endometrial glandular cells. These findings suggest that p27 is functionally involved in progestin-induced growth suppression of normal and malignant endometrial epithelial cells and that up-regulation of the p27 protein by progestins possibly occurs via posttranslational mechanisms.