Recent studies suggest that progesterone may possess anti-tumorigenic properties. However, a growth-modulatory role of progestins in human cancer cells remains obscure. With the discovery of a new class of membrane progesterone receptors (mPRs) belonging to the progestin and adipoQ receptor gene family, it becomes important to study the effect of this hormone on proliferation of tumor cells that do not express classical nuclear progesterone receptors (nPRs). To identify a cell line expressing high levels of mPRs and lacking nPRs, we examined mRNA levels of nPRs and three forms of mPRs in sixteen human tumor cell lines of different origin. High expression of mPR mRNA has been found in pancreatic adenocarcinoma BxPC3 cells, while nPR mRNA has not been detected in these cells. Western blot analysis confirmed these findings at the protein level. We revealed specific binding of labeled progesterone in these cells with affinity constant similar to that of human mPR expressed in yeast cells. Progesterone at high concentration of 20 μM significantly reduced the mRNA levels of proliferation markers Ki67 and PCNA, as well as of cyclin D1, and increased the mRNA levels of cyclin dependent kinase inhibitors p21 and p27. Progesterone (1 μM and 20 μM) significantly inhibited proliferative activity of BxPC3 cells. These results point to anti-proliferative effects of the progesterone high concentrations on BxPC3 cells and suggest that activation of mPRs may mediate this action. Our data are a starting point for further investigations regarding the application of progesterone in pancreatic cancer.
Irregular uterine bleeding is a major side effect of long-acting progestogen-only contraceptives in women, and is the primary reason women discontinue their use. In this study, a mouse model of endometrial breakdown was established using a subcutaneous progesterone implant to understand how irregular bleeding begins. Although progestogens sustained decidualization, endometrial breakdown was still observed in this model. We, therefore, hypothesized that endometrial breakdown might involve functional progesterone withdrawal. Using co-immunoprecipitation assays, we observed the constitutive activation of nuclear factor kappa-b (NF-kappa B) p65 and its interaction with the progesterone receptor (PGR); moreover, transcriptional activity of the PGR was also repressed by NF-kappa B activity in primary mouse and human decidual stromal cells that mimic progesterone maintenance. Yet the ratio of PGR-B to PGR-A was not increased in the mouse model. In vivo comparison of endometrial breakdown induced by progesterone withdrawal to that seen during sustained progesterone exposure, in the presence of NF-kappa B inhibitors, revealed that NF-k kappa B-mediated functional progesterone withdrawal is involved in endometrial breakdown in this implant model. These data prompt further studies to determine the homology of this functional progesterone withdrawal mechanism in human endometrium. (C) 2016 Wiley Periodicals, Inc.
Summary Background Progesterone administration has been shown to reduce the risk of preterm birth and neonatal morbidity in women at high risk, but there is uncertainty about longer term effects on the child. Methods We did a double-blind, randomised, placebo-controlled trial of vaginal progesterone, 200 mg daily taken from 22–24 to 34 weeks of gestation, on pregnancy and infant outcomes in women at risk of preterm birth (because of previous spontaneous birth at ≤34 weeks and 0 days of gestation, or a cervical length ≤25 mm, or because of a positive fetal fibronectin test combined with other clinical risk factors for preterm birth [any one of a history in a previous pregnancy of preterm birth, second trimester loss, preterm premature fetal membrane rupture, or a history of a cervical procedure to treat abnormal smears]). The objective of the study was to determine whether vaginal progesterone prophylaxis given to reduce the risk of preterm birth affects neonatal and childhood outcomes. We defined three primary outcomes: fetal death or birth before 34 weeks and 0 days gestation (obstetric), a composite of death, brain injury, or bronchopulmonary dysplasia (neonatal), and a standardised cognitive score at 2 years of age (childhood), imputing values for deaths. Randomisation was done through a web portal, with participants, investigators, and others involved in giving the intervention, assessing outcomes, or analysing data masked to treatment allocation until the end of the study. Analysis was by intention to treat. This trial is registered at ISRCTN.com , number ISRCTN14568373. Findings Between Feb 2, 2009, and April 12, 2013, we randomly assigned 1228 women to the placebo group (n=610) and the progesterone group (n=618). In the placebo group, data from 597, 587, and 439 women or babies were available for analysis of obstetric, neonatal, and childhood outcomes, respectively; in the progesterone group the corresponding numbers were 600, 589, and 430. After correction for multiple outcomes, progesterone had no significant effect on the primary obstetric outcome (odds ratio adjusted for multiple comparisons [OR] 0·86, 95% CI 0·61–1·22) or neonatal outcome (OR 0·62, 0·38–1·03), nor on the childhood outcome (cognitive score, progesterone group vs placebo group, 97·3 [SD 17·9] vs 97·7 [17·5]; difference in means −0·48, 95% CI −2·77 to 1·81). Maternal or child serious adverse events were reported in 70 (11%) of 610 patients in the placebo group and 59 (10%) of 616 patients in the progesterone group (p=0·27). Interpretation Vaginal progesterone was not associated with reduced risk of preterm birth or composite neonatal adverse outcomes, and had no long-term benefit or harm on outcomes in children at 2 years of age. Funding Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnership. The EME Programme is funded by the MRC and NIHR, with contributions from the Chief Scientist Office in Scotland and National Institute for Social Care and Research in Wales.
This study aimed to evaluate steroid hormones in foals born from mares treated for ascending placentitis with different combinations of trimethoprim-sulfamethoxazole (TMS), flunixin meglumine (FM), long-acting altrenogest (ALT) and estradiol cypionate (ECP) for ten consecutive days, starting two days after experimental induction of placentitis with Streptococcus zooepidemicus. Fourty-six pregnant mares and respective foals were assigned as healthy group (Control, n = 8) or treated groups as follows: TMS+FM (n = 8), TMS+FM+ALT (n = 8), TMS+FM+ALT+ECP (n = 6), TMS+FM+ECP (n = 6) and no treatment (NO TREAT n = 10). At delivery, foals were classified as high-risk or low-risk based on clinical and hematologic findings, and survival rates were recorded during the first week of life for comparisons across groups. Cortisol, progesterone, 17α–OH–progesterone, and pregnenolone concentrations were determined via immunoassays in 31 of the 46 foals immediately after foaling (0 h), at 12, 24, 48 h, and seven days post-partum (168h). At birth, serum cortisol concentrations were higher in Control and TMS+FM+ECP foals than in remaining groups (p < 0.05). Foals in TMS+FM+ALT and TMS+FM groups had higher 17α–OH–progesterone concentrations at 24 h and 48 h, respectively (p < 0.05). Pregnenolone concentrations were higher in TMS+FM than TMS+FM+ALT+ECP foals at 7 days (p < 0.05). High-risk and non-surviving foals had decreased concentrations of cortisol at parturition, but increased concentrations of progesterone from 0 h to 48 h. Pregnenolone and 17α–OH–progesterone concentrations were increased and pregnenolone after 12 h in high-risk and non-surviving foals (p < 0.05). In conclusion, adding ECP to the treatment of experimentally-induced placentitis appears to improve foal viability and endocrine response. Cortisol and progestogen profiles were abnormal in high-risk and non-surviving foals, and those treated with ALT or TMS+FM only.
Background: Administration of exogenous progesterone for luteal phase support has become a standard of practice. Intramuscular (IM) injections of progesterone in oil (PIO) and vaginal administration of progesterone are the primary routes of administration. This report describes the administration preferences expressed by women with infertility that were given progesterone vaginal insert (PVI) or progesterone in oil injections (PIO) for luteal phase support during fresh IVF cycles. Methods: A questionnaire to assess the tolerability, convenience, and ease of administration of PVI and PIO given for luteal phase support was completed by infertile women diagnosed with PCOS and planning to undergo IVF. The women participated in an open-label study of highly purified human menopausal gonadotropins (HP-hMG) compared with recombinant FSH (rFSH) given for stimulation of ovulation. Results: Most women commented on the convenience and ease of administration of PVI, while a majority of women who administered IM PIO described experiencing pain. In addition, their partners often indicated that they had experienced at least some anxiety regarding the administration of PIO. The most distinguishing difference between PVI and PIO in this study was the overall patient preference for PVI. Despite the need to administer PVI either twice a day or three times a day, 82.6% of the patients in the PVI group found it "very" or "somewhat convenient" compared with 44.9% of women in the PIO group. Conclusions: The results of this comprehensive, prospective patient survey, along with findings from other similar reports, suggest that PVI provides an easy-to-use and convenient method for providing the necessary luteal phase support for IVF cycles without the pain and inconvenience of daily IM PIO. Moreover, ongoing pregnancy rates with the well-tolerated PVI were as good as the pregnancy rates with PIO.
Progesterone Receptors (PRs) are critical effectors of estrogen receptor (ER) signaling required for mammary gland development and reproductive proficiency. In breast and reproductive tract malignancies, PR expression is a clinical prognostic marker of ER action. While estrogens primarily regulate PR expression, other factors likely contribute to a dynamic range of receptor expression across diverse tissues. In this study, we identified estrogen-independent but progestin (R5020)-dependent regulation of ER target genes including in ER+/PR+ cancer cell lines. R5020 (10 nM–10 μM range) induced dose-dependent PR mRNA and protein expression in the absence of estrogen but required both PR and ERα. Antagonists of either PR (RU486, onapristone) or ERα (ICI 182,780) attenuated R5020 induction of , , and . Chromatin immunoprecipitation (ChIP) assays performed on ER+/PR+ cells demonstrated that both ERα and PR were recruited to the same ERE/Sp1 site-containing region of the proximal promoter in response to high dose progestin (10 μM). Recruitment of ERα and PR to chromatin and subsequent PR mRNA induction were dependent upon rapid activation of MAPK/ERK and AKT; inhibition of these kinase pathways via U0126 or LY294002 blocked these events. Overall, we have identified a novel mechanism of ERα activation initiated by rapid PR-dependent kinase pathway activation and associated with phosphorylation of ERα Ser118 for estrogen-independent but progestin-dependent ER/PR cross talk. These studies may provide insight into mechanisms of persistent ER-target gene expression during periods of hormone (i.e. estrogen) ablation and suggest caution following prolonged treatment with aromatase or CYP17 inhibitors (i.e. contexts when progesterone levels may be abnormally elevated).
▶ 3D models of lamprey PR indicate that it can bind both 7α-OH-progesterone and 15α-OH-progesterone. ▶ Lamprey PR contains an important Met-277 that corresponds to Leu-887 on human PR. ▶ Methionine-277 on lamprey PR has a specific interaction with 15α-OH-progesterone. ▶ Lamprey PR could be a target for controlling reproduction of lamprey. Sea lamprey, a basal vertebrate, contains a progesterone receptor [PR]. An unusual property of lamprey is that gonadotropin-releasing hormone induces synthesis of 15α-hydroxy-progesterone [15α-OH-P] instead of progesterone. There also is indirect evidence for 7α-OH-P in lamprey serum. To determine if there is a structural basis for the binding of 7α-OH-P and 15α-OH-P to lamprey PR, we constructed 3D models of the lamprey PR complexed with progesterone, 7α-OH-P and 15α-OH-P. These 3D models reveal that Met-277 in lamprey PR has a specific interaction with the 15α-hydroxyl on 15α-OH-P and with Met-192, which also contacts the 15α-hydroxyl group. We also find that 7α-OH-P has favorable contacts with side-chains in lamprey PR. BLAST searches reveal that Met-277 on lamprey PR is unique among vertebrate PRs. This unique site on lamprey PR could be a target for compounds to control reproduction in sea lamprey, an environmental pest in Lake Michigan.
Progesterone receptor (PR) expression is used as a biomarker of oestrogen receptor-alpha (ER alpha) function and breast cancer prognosis. Here we show that PR is not merely an ER alpha-induced gene target, but is also an ER alpha-associated protein that modulates its behaviour. In the presence of agonist ligands, PR associates with ER alpha to direct ER alpha chromatin binding events within breast cancer cells, resulting in a unique gene expression programme that is associated with good clinical outcome. Progesterone inhibited oestrogen-mediated growth of ER alpha(+) cell line xenografts and primary ER alpha(+) breast tumour explants, and had increased anti-proliferative effects when coupled with an ER alpha antagonist. Copy number loss of PGR, the gene coding for PR, is a common feature in ER alpha(+) breast cancers, explaining lower PR levels in a subset of cases. Our findings indicate that PR functions as a molecular rheostat to control ER alpha chromatin binding and transcriptional activity, which has important implications for prognosis and therapeutic interventions.