Progesterone Receptor Signaling Pathways Research Articles

Treatment modalities for advanced solid pseudopapillary tumor of the pancreas.

e16327 Background: Solid pseudopapillary tumor (SPT) of the pancreas is a rare low-grade malignant tumor. However, a minority of SPT patients present aggressive behavior and develop recurrent or metastatic diseases. The treatment strategies of advanced SPTs remain unclear. Our study aimed to explore the treatment modalities of aggressive SPTs and the role of endocrine therapy. Methods: The data on clinicopathologic characteristics and treatment of advanced SPT patients from Sun Yat-Sen University Cancer Center and Shen Zhen People's Hospital were collected. The treatment modalities were explored by co-analyzing our local cohort and published literatures. Single sample gene set enrichment analysis (ssGSEA) was used to explore the functional enrichment pathway (GSE43795). Fresh surgical specimens from 10 SPT patients were collected for endocrine drugs sensitive test in vitro by performing tumor histoculture end-point staining computer image analysis (TECIA). Results: A total of 77 advanced SPT patients including 14 cases in our local cohort and 63 cases from published literatures were enrolled. 60 patients received local treatment including cytoreductive surgery, interventional therapy or radiation therapy. 55 patients who had undergone cytoreductive surgery have better outcome compared with others (P = 0.046, HR = 4.12). 31 patients received systemic chemotherapy and 6 patients received targeted therapy. There were 2 patients achieved partial response after chemotherapy. In our local cohort, 5 patients received endocrine therapy with tamoxifen plus megestrol. One patient achieved partial response with duration of response (DOR) of 89 months. 4 patients showed stable disease. ssGSEA for GSE43795 showed that Wnt signaling pathway and its inhibitory pathway-progesterone receptor signaling pathway were simultaneously enriched in SPTs. The results of endocrine drug sensitive test in vitro by TECIA showed response rate of 50% (5/10) in megestrol group, 40% (4/10) in tamoxifen group, and 30% (3/10) in testosterone propionate group. Conclusions: Advanced SPTs did not appear chemosensitive. Cytoreductive surgery may improve survival. Simultaneously enriching Wnt and progesterone receptor signaling pathway may partially explain the low aggressive ability of SPT and their unbalance may lead to the aggressive behavior of SPT. Endocrine therapy with tamoxifen plus megestrol, by enhancing the progesterone signaling pathway, seems to be a promising regimen for advanced SPTs, which is worth to be noted and further studied.

Unraveling Roles of miR-27b-3p as a Potential Biomarker for Breast Cancer in Malay Women via Bioinformatics Analysis.

Abnormal miRNA expression has been associated with breast cancer. Knowing miRNA and its target genes gives a better understanding of the biological mechanism behind the development of breast cancer. Here, we evaluated the potential prognostic and predictive values of miRNAs in breast cancer development by analyzing Malay women with breast cancer expression profiles. Seven differentially expressed miRNAs (DEMs) were subjected to miRNA‒target interaction network analysis (MTIN). A comprehensive MTIN was developed by integrating the information on miRNA and target gene interactions from five independent databases, including DIANA-TarBase, miRTarBase, miRNet, miRDB, and DIANA-microT. To understand the role of miRNAs in the progress of breast cancer, functional enrichment analysis of the miRNA target genes was conducted, followed by survival analysis to assess the prognostic values of the miRNAs and their target genes. In total, 1416 interactions were discovered among seven DEMs and 1274 target genes with a confidence score (CS) > 0.8. The overall survival analysis of the three most DEMs revealed a significant association of miR-27b-3p with poor prognosis in the TCGA breast cancer patient cohort. Further functional analysis of 606 miR-27b-3p target genes revealed their involvement in cancer-related processes and pathways, including the progesterone receptor signaling pathway, PI3K-Akt pathway, and EGFR transactivation. Notably, six high-confidence target genes (BTG2, DNAJC13, GRB2, GSK3B, KRAS, and UBR5) were discovered to be associated with worse overall survival in breast cancer patients, underscoring their essential roles in breast cancer development. Thus, we suggest that miR-27b-3p has significant potential as a biomarker for detecting breast cancer and can provide valuable understanding regarding the molecular mechanisms of the disease.

Abstract 2625: Identification of CTX-30916 as a novel antagonist of progesterone receptor signaling pathways

Abstract Breast cancer is the most commonly diagnosed cancer in women and the second leading cause of cancer related death in women. Progesterone is a major mitogen in the adult human mammary epithelium that, in addition to estrogen, is a key driver of breast cancer cell proliferation. Activated PR signaling through MAPK-driven phosphorylation of the progesterone receptor (PR) is also an important driver of breast cancer stem cells. PR expression is associated with the presence of estrogen receptor-alpha (ESR1) mutations that are constitutively active and linked to resistance in the clinic in response to aromatase inhibitors, antiestrogens and CDK4/6 inhibitors. Thus, PR may play a role in tumor relapse and resistance in the clinic and blocking both estrogen and progesterone receptors would likely be an effective approach in 2L treatment for patients with advanced breast cancer. There is great interest in evaluating antiprogestins in the clinic in combination with antiestrogens or CDK4/6 inhibitors. Apristor®, an extended release formulation of onapristone, a full antagonist of PR, that has efficacy in multiple in vivo and in vitro models in combination with antiestrogestins and CDK4/6 inhibitors, is currently being evaluated in several human clinical trials. In this study we have examined the in vitro properties of CTX-30916, a novel mono-N-desmethyl analog of onapristone. CTX-30916 binds potently to PR and acts as an antagonist in cell-based transfection assays. CTX-30916 displays selectivity against other steroid receptors in binding assays and is also a potent inhibitor of T47D breast cancer cell proliferation. Interestingly, CTX-30916 leads to a unique co-regulator binding pattern in the Microarray Assay for Real-time Co-regulator-Nuclear receptor interaction (MARCoNI) assay compared with onapristone and mifepristone indicating that the co-regulator peptide-PR interaction landscape is different between the various antiprogestins. These data suggest that CTX-30916 binding to PR leads to a distinct receptor conformation and antagonizes PR signaling pathways in cancer through a unique mechanism of action compared to other antiprogestins. Citation Format: Deepak Lala, Tasir Haque. Identification of CTX-30916 as a novel antagonist of progesterone receptor signaling pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2625.

Equine placentitis is associated with a downregulation in myometrial progestin signaling†.

The current study aimed to elucidate the mechanisms underlying myometrial activation during equine placentitis related to progestogens and the progesterone receptor signaling pathways. Placentitis was induced via intracervical inoculation with Streptococcus equi ssp zooepidemicus in mares at approximately 290 days of gestation (placentitis group; n=6) with uninoculated gestationally matched mares as controls (n=4). Mares in the placentitis and control groups were euthanized, and myometrial samples were collected from two regions: region 1-parallel to active placentitis lesion with placental separation in placentitis group (P1) or caudal pole of the placenta in control group (C1); and region 2-parallel to apparently normal placenta without separation in placentitis group (P2) or uterine body in control group (C2). In the current study, SRD5A1 and AKR1C23, which encode for the key P4 metabolizing enzymes, were downregulated in P1 in comparison to C1, C2, and P2, and this was associated with a decline (P<0.05) in 5αDHP, allopregnanolone (3αDHP), and 20αDHP in P1 in comparison to C1. Further, myometrial expression of PR was downregulated (P<0.05) in P1 in comparison to C1 and P2, and this was associated with activation of the inflammatory cascade as reflected by significant upregulation of IL-1β and IL-8 in P1 in comparison to C1, C2, and P2, and supported by increased tissue leukocytes in P1 in comparison to C1. In conclusion, equine placentitis is associated with a localized withdrawal of progestins and a downregulation of the PR in the myometrium concomitant with upregulation of inflammatory cytokines and subsequent myometrial activation.

Pathogenesis and Treatment of Hepatitis E Virus Infection

Hepatitis E has been considered to be a travel-associated, acute, self-limiting liver disease that causes fulminant hepatic failure in specific high-risk groups only. However, hepatitis E virus (HEV) infection can also be acquired in industrialized countries-HEV genotype 3 infection is a zoonosis, with pigs and rodents serving as animal reservoirs. In recent years, cases of chronic HEV infection that were associated with progressive liver disease have been described in several cohorts of immunocompromised individuals, including recipients of organ transplants. The topic of hepatitis E is therefore re-emerging and has raised the following important questions: what is the risk for HEV infection in Western countries (eg, from eating uncooked meat)? How frequently does chronic hepatitis E develop among human immunodeficiency virus-infected patients and recipients of organ transplants? What are the treatment options? What is the current status of vaccine development? What do we know about the pathogenesis of HEV infection, and why does it have a more severe course in pregnant women? This review summarizes the current knowledge on the pathogenesis and treatment of HEV infection.

Discovery of a novel mechanism of steroid receptor antagonism: WAY-255348 modulates progesterone receptor cellular localization and promoter interactions

WAY-255348 is a potent nonsteroidal progesterone receptor (PR) antagonist previously characterized in rodents and nonhuman primates. This report describes the novel mechanism by which WAY-255348 inhibits the activity of progesterone. Most PR antagonists bind to and block PR action by inducing a unique “antagonist” conformation of the PR. However, WAY-255348 lacks the bulky side chains or chemical groups that have been associated with the conformation changes of helix 12 that lead to functional antagonism. We show that WAY-255348 achieves antagonist activity by binding to and subsequently preventing progesterone-induced nuclear accumulation, phosphorylation and promoter interactions of the PR. This effect was concentration dependent, as high concentrations of WAY-255348 alone are able to induce nuclear translocation, phosphorylation and subsequent promoter interactions resulting in partial agonist activity at these concentrations. However, at lower concentrations where nuclear accumulation and phosphorylation are prevented, the progesterone-induced DNA binding is blocked along with PR-dependent gene expression. Analysis of the PR conformation induced by WAY-255348 using a limited protease digestion assay, suggested that the WAY-255348 bound PR conformation was similar to that of a progesterone agonist-bound PR and distinct from steroidal antagonist-bound PR conformations. Furthermore, the recruitment and binding of peptides derived from nuclear receptor co-activators is consistent with WAY-255348 inducing an agonist-like conformation. Taken together, these data suggest that WAY-255348 inhibits PR action through a novel molecular mechanism that is distinct from previously studied PR modulators and may be a useful tool to further understanding of PR signaling pathways. Development of therapeutic molecules with this ‘passive’ antagonism mechanism may provide distinct advantages for patients with reproductive disorders or PR positive breast cancers.

Regulation of steroid hormone receptor function by the 52-kDa FK506-binding protein (FKBP52).

The large FK506-binding protein FKBP52 has been characterized as an important positive regulator of androgen, glucocorticoid and progesterone receptor signaling pathways. FKBP52 associates with receptor-Hsp90 complexes and is proposed to have roles in both receptor hormone binding and receptor subcellular localization. Data from biochemical and cellular studies have been corroborated in whole animal models as fkbp52-deficient male and female mice display characteristics of androgen, glucocorticoid and/or progesterone insensitivity. FKBP52 receptor specificity and the specific phenotypes displayed by the fkbp52-deficient mice have firmly established FKBP52 as a promising target for the treatment of a variety of hormone-dependent diseases. Recent studies demonstrated that the FKBP52 FK1 domain and the proline-rich loop within this domain are functionally important for FKBP52 regulation of receptor function. Based on these data, efforts are currently underway to target the FKBP52 FK1 domain and the proline-rich loop with small molecule inhibitors.

High viral load and deregulation of the progesterone receptor signaling pathway: Association with Hepatitis E-related poor pregnancy outcome

Hepatitis E virus (HEV) infection is associated with high maternal and fetal mortalities. A prospective study was undertaken to evaluate the role of viral and host factors in HEV related pregnancy outcomes. The study included HEV infected pregnancy cases; acute viral hepatitis (AVH), n=100 and fulminant hepatic failure (FHF), n=43, and healthy pregnancy cases, n=50. HEV genotypes and viremia were studied by nucleotide sequencing and real time PCR, respectively. Progesterone receptor (PR) gene mutations (PROGINS) were studied by PCR, PR expression at the mRNA and protein levels in the placenta were studied by semi-quantitative RT-PCR and immunohistochemistry, respectively. Progesterone induced blocking factor (PIBF) expression was studied by RT-PCR in blood. Serum interleukin-10 (IL-10) and interleukin-12 (IL-12) levels were assayed by ELISA. HEV viral load was significantly higher in FHF than AVH (p<0.001) and in cases with fetal mortality in AVH (p=0.001) and FHF (p=0.018). PROGINS were predominant in FHF compared to AVH (p=0.26) and showed reduced mRNA and protein expression. The risk of fetal mortality in AVH was two times higher (OR, 2.190; CI, 0.303-15.85) and maternal and fetal mortalities in FHF were 4-fold (OR, 4.0; CI, 0.363-44.113) increased in PROGINS carriers. PR and PIBF expression was lower in AVH and even lower in FHF compared to healthy controls. The higher IL-12/IL-10 ratio observed in FHF compared to other groups correlated with fetal mortality in AVH and FHF (p<0.001). In conclusion, reduced expression of PR and PIBF, a higher IL-12/IL-10 ratio, and a high viral load results in poor pregnancy outcome in Hepatitis E.

GCUNC-45 Is a Novel Regulator for the Progesterone Receptor/hsp90 Chaperoning Pathway

The hsp90 chaperoning pathway is a multiprotein system that is required for the production or activation of many cell regulatory proteins, including the progesterone receptor (PR). We report here the identity of GCUNC-45 as a novel modulator of PR chaperoning by hsp90. GCUNC-45, previously implicated in the activities of myosins, can interact in vivo and in vitro with both PR-A and PR-B and with hsp90. Overexpression and knockdown experiments show GCUNC-45 to be a positive factor in promoting PR function in the cell. GCUNC-45 binds to the ATP-binding domain of hsp90 to prevent the activation of its ATPase activity by the cochaperone Aha1. This effect limits PR chaperoning by hsp90, but this can be reversed by FKBP52, a cochaperone that is thought to act later in the pathway. These findings reveal a new cochaperone binding site near the N terminus of hsp90, add insight on the role of FKBP52, and identify GCUNC-45 as a novel regulator of the PR signaling pathway.

Progesterone receptor transcription and non-transcription signaling mechanisms

The diverse effects of progesterone on female reproductive tissues are mediated by the progesterone receptor (PR), a member of the nuclear receptor family of ligand-dependent transcription factors. Thus, PR is an important therapeutic target in female reproduction and in certain endocrine dependent cancers. This paper reviews our understanding of the mechanism of action of the most widely used PR antagonist RU486. Although RU486 is a competitive steroidal antagonist that can displace the natural hormone for PR, it’s potency derives from additional “active antagonism” that involves inhibiting the activity of PR hormone agonist complexes in trans through heterodimerization and competition for binding to progesterone response elements on target DNA, and by recruitment of corepressors that have the potential to actively repress gene transcription. An additional functional role for PR has recently been defined whereby a subpopulation of PR in the cytoplasm or cell membrane is capable of mediating rapid progesterone induced activation of certain signal transduction pathways in the absence of gene transcription. This paper also reviews recent results on the mechanism of the extra-nuclear action of PR and the potential biological roles and implications of this novel PR signaling pathway.

Effect of the preovulatory LH surge on bovine follicular progesterone receptor mRNA expression

A growing body of evidence indicates that intrafollicular progesterone receptor signaling pathways are obligatory for follicle rupture. However, the intrafollicular localization and regulation of progesterone receptor expression during the periovulatory period in cattle are not known. In this study, we determined the effect of the preovulatory gonadotropin surge on localization and expression of progesterone receptor mRNA in bovine periovulatory follicular and luteal tissue. Ovaries containing preovulatory follicles or new corpora lutea (CL) were collected at approximately 0, 6, 12, 18, 24 (preovulatory follicles) and 48 h (CL) after a GnRH-induced LH surge ( n=5–8 per timepoint). Expression of progesterone receptor mRNA was detected in periovulatory follicular and luteal tissue at all timepoints examined. Relative levels of progesterone receptor mRNA were dramatically upregulated within 6 h after the LH surge compared to all other time points ( P<0.0001). In situ hybridization analysis revealed that the significant increase in progesterone receptor mRNA expression was localized to the granulosal layer of preovulatory follicles. Our results indicate that progesterone receptor mRNA expression is upregulated specifically in the granulosal layer of bovine preovulatory follicles following the LH surge. Progesterone receptor signaling pathways may help mediate the effects of the preovulatory LH surge on follicle rupture in cattle.

Progesterone Receptor Contains a Proline-Rich Motif that Directly Interacts with SH3 Domains and Activates c-Src Family Tyrosine Kinases

Steroid hormones have rapid nongenomic effects on cell-signaling pathways, but the receptor mechanisms responsible for this are not understood. We have identified a specific polyproline motif in the amino-terminal domain of conventional progesterone receptor (PR) that mediates direct progestin-dependent interaction of PR with SH3 domains of various cytoplasmic signaling molecules, including c-Src tyrosine kinases. Through this interaction, PR is a potent activator of Src kinases working by an SH3 domain displacement mechanism. By mutagenesis, we also show that rapid progestin-induced activation of Src and downstream MAP kinase in mammalian cells is dependent on PR-SH3 domain interaction, but not on the transcriptional activity of PR. Preliminary evidence for the biological significance of this PR signaling pathway through regulatory SH3 domains was shown with respect to an influence on progestin-induced growth arrest of breast epithelial cells and induction of Xenopus oocyte maturation.