Mifepristone Research Articles (Page 1)

Abstract The endocrine status of the patient is a critical factor that may modulate the immune response in breast cancer and, accordingly, should be considered during immunotherapy regimens. Given the immunosuppressive and tolerogenic activities of the sexual hormone progesterone and its roles in promoting breast cancer initiation, we aim to evaluate the effect of the antagonist of the classical progesterone receptor, Mifepristone (MIFE), as an endocrine therapy to alter the tumor microenvironment, and particularly to shape an immunogenic and immunotherapy-responsive profile. We evaluated the breast tumor immune landscape both in a mouse model of luminal tumors (C4HD) treated with a synthetic progestin MPA and with MIFE; and in human tumor samples derived from the MIPRA clinical trial (NCT02651844), where breast cancer patients harbouring HR+ tumors were treated with MFP for 14 days before surgery. Using RNA-seq, bioinformatics tools and flow cytometry, we interrogated the C4HD tumor immune infiltration profile after MPA and MIFE treatment, including several global gene expression signatures associated with T-cell exclusion and Immune Checkpoint Inhibitors (ICI) sensitivity and resistance. We observed that treatment with MFP in HR+ luminal breast tumors restrains the progestin-mediated tolerogenic infiltrate composed of Tregs, exhausted CD8+ T cells and TAM macrophages. Importantly, MIFE downregulates the suppressive pathway of IDO, CXCL5, VEGF and Galectin-9, which in turn contributes to the persistence of a population of CD8+ T cells that highly produce granzymes and express lower TIM-3 and PD-1, exhibiting a reinvigorating phenotype. On the contrary, MIFE treatment upregulated several immune-associated genes such as chemokines, granzymes, ICOS-L, EOMES, CD86, CD8 and PD-L1. More importantly, we showed that in both mouse models and human tumors, treatment with MIFE reverts transcriptional signatures associated with T cell exclusion and ICI resistance and significantly upregulates programs associated with immunogenic cell death and PD-1/PD-L1 treatment response. To summarize, our results demonstrate that endocrine therapy as MIFE can foster in HR+ tumors a complete remodelling of the immune landscape, promoting immune cell infiltration and immunogenicity. As a result of the neoadjuvant MIFE treatment, HR+ luminal tumors that traditionally were considered “cold” tumors are now heavily enriched with an immunogenic PD-L1-expressing infiltrate, thus opening a new window of treatment opportunity that may sensitize luminal breast tumors to ICI. Citation Format: Mariana Salatino, Joaquin Pedro Merlo, Tomas Dalotto-Moreno, Magalí Bertón, Ramiro Martin Perrotta, Andres Elia, Karina V. Mariño, Claudia M. Lanari, Gabriel A. Rabinovich. Antiprogestin- mediated endocrine therapy activates immunotherapy- responsive programs in hormone receptor positive breast tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6165.

Preparation of liposomes co-encapsulating doxorubicin and mifepristone for treating multidrug-resistant cancer

Effect of anti-estrogen and anti-progesterone on spermatogenesis, testosterone production and expression of steroidogenic enzyme genes in adult male rats.

Tumor metastasis is a main cause of death in patients with breast cancer. The cross-talk between cancer-associated fibroblasts (CAFs) and tumor cells plays an important role in promoting tumor invasion and metastasis. It is important to develop a novel delivery system to inhibit tumor development by simultaneously targeting both CAFs and tumor cells. The main objective of this research was to prepare nanoparticles to inhibit tumor proliferation and migration by blocking the cross-talk of tumor-CAFs. Additionally, a novel "MCF- 7+NIH/3T3" mixed cell model was established to mimic the tumor microenvironment (TME). In this study, the pH-responsive nanoparticles (MIF/DOX-sul-HA NPs) based on sulfated hyaluronic acid (sul-HA) polymers were prepared for co-delivery of doxorubicin (DOX) and mifepristone (MIF). The effects of anti-proliferation and anti-metastasis of MIF/DOX-sul-HA NPs were investigated both in vitro and in vivo. The results showed that MIF/DOX-sul-HA NPs were nearly spherical in shape with narrow particle size distribution and pH-responsive drug release, and could be taken up by both MCF-7 and NIH/3T3 cells. Compared with MCF-7 cells alone, the anti-tumor effect of single DOX was weak in the "MCF-7+NIH/3T3" mixed cell model. MIF/DOX-sul-HA NPs exhibited strong effects of anti-proliferation and anti-metastasis than the free single drug. The sul-HA nanoparticles for co-delivery of DOX and MIF could be a promising combined therapy strategy for the treatment of breast cancer.

The aldosterone (ALDO)-sensitive distal nephron is typically defined as: the late distal convoluted tubule (DCT2), connecting tubule (CNT) and cortical collecting duct (CCD). ALDO-sensitivity is defined by 11βHSD2 (11β) activity (which inactivates corticosterone, CORT); mineralocorticoid (MR) rather than glucocorticoid receptor (GR) expression; and the target epithelial sodium channel (ENaC). Recent studies have reported ALDO-insensitive, but MR-dependent ENaC activity in DCT2/CNT and that CORT-stimulated ENaC may be relevant in MR antagonism as 4th line anti-hypertensive therapy. Whilst functional evidence of ALDO-insensitive ENaC activity is compelling, corticosteroid-regulated Na+ transport along the distal nephron is not fully defined. AIM: to determine 11βHSD2, MR and GR expression alongside Na+ transporter localisation in murine distal nephron and assess the endogenous receptor(s) underpinning steroid-stimulated ENaC activity.Male C57BL/6 mouse kidney sections were subject to multiplex immunofluorescence (11β, MR and GR) and immunohistochemical labelling (NCC, TRPV5, γ-ENaC and AQP2). Images were co-registered, annotated and analysed using Halo® software. Steroid-induced ENaC-mediated currents were measured in mCCDcl1 and primary CD cells. Carbenoxolone (CBX), mifepristone (MF) or PF-03882845 (PF) were used to inhibit 11β, GR and MR, respectively.Distal nephron segments were defined as: DCT - NCC; DCT/CNT - NCC and TRPV5; CNT - TRPV5; CNT/CCD - TRPV5 and γ-ENaC/AQP2; CCD - γ-ENaC/AQP2. We did not detect NCC and γ-ENaC co-localisation. Average cells/section, DCT: 874±39; DCT/CNT: 238±31; CNT: 198±63; CNT/CCD: 831±282; CCD: 2262±231 ( n=3). Negligible numbers of cells expressed both MR and GR.DCT was predominantly 11β- (~90%) and GR dominant (GR:MR ratio ~7:1). In 11β+ cells (~10%), GR was also dominant (GR:MR ratio ~4:1). DCT/CNT and CNT were mainly 11β- (~85 and ~75%, respectively), where MR and GR were similar. In 11β+ cells, MR and GR were similar in DCT/CNT but MR was greater in CNT (MR:GR ratio ~4:1). CNT/CCD contained a near equal split of 11β- (~52%) and 11β+ (~48%) cells. MR and GR were similar in 11β- cells, but 11β+ cells were almost exclusively MR (MR:GR ratio ~37:1). In CCD, ~35% of cells were 11β-, MR and GR were similar, and ~65% cells were 11β+, these were predominantly MR (MR:GR ratio ~30:1).In mCCDcl1 ( n=8-11) and primary CD cells ( n=6), ALDO-induced ENaC activity was inhibited by MR ( p<0.001) but not GR antagonists. DEX-induced ENaC activity was inhibited by GR ( p<0.001) but not MR antagonists. CORT-induced ENaC activity was modestly inhibited by MR ( p<0.05) but not by GR antagonists.Our data suggest that the DCT is a glucocorticoid-responsive segment, with 11β+ cells becoming progressively more dominant from CNT to CCD. The appearance of ENaC in the late CNT and particularly CCD, alongside 11β and MR, suggest these segments reflect the mineralocorticoid-responsive, and thus aldosterone-sensitive distal nephron. Kidney Research UK, The Royal Society This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ball-milling and harsh manufacturing processes often generate crystal disorder which have practical implications on the physical and chemical stabilities of solid drugs during subsequent storage, transport, and handling. The impact of the physical state of solid drugs, containing different degrees/levels of crystal disorder, on their autoxidative stability under storage has not been widely investigated. This study investigates the impact of differing degrees of crystal disorder on the autoxidation of Mifepristone (MFP) to develop a predictive (semi-empirical) stability model. Crystalline MFP was subjected to different durations of ambient ball milling, and the resulting disorder/ amorphous content was quantified using a partial least square (PLS) regression model based on Raman spectroscopy data. Samples of MFP milled to generate varying levels of disorder were subjected to a range of (accelerated) stability conditions, and periodically sampled to examine their recrystallization and degradation extents. Crystallinity was monitored by Raman spectroscopy, and the degradation was evaluated by liquid chromatography. The analyses of milled samples demonstrated a competition between recrystallization and degradation via autoxidation of MFP, to different extents depending on stability conditions/exposure time. The degradation kinetics were analyzed by accounting for the preceding amorphous content, and fitted with a diffusion model. An extended Arrhenius equation was used to predict the degradation of stored samples under long-term (25°C/60% RH) and accelerated (40°C/75% RH, 50°C/75% RH) stability conditions. This study highlights the utility of such a predictive stability model for identifying the autoxidative instability in non-crystalline/partially crystalline MFP, owing to the degradation of the amorphous phases. This study is particularly useful for identifying drug-product instability by leveraging the concept of material sciences.

Abstract Since antiprogestins inhibit the growth of preclinical mammary tumor models expressing higher levels of progesterone receptor (PR) isoform A (PRA) than isoform B (PRB), we designed a window-of-opportunity trial (MIPRA; NCT02651844) to study the benefits of mifepristone (MFP) in luminal breast carcinomas from postmenopausal patients selected by their PR+ expression (>50%) and their PR isoform ratio (PRA/PRB>1.5; PRA-H). A decrease in the cell proliferation marker Ki67 was registered after treatment in 14 out of the 20 tumors evaluated. This inhibition was associated with a decrease in PR, estrogen receptor (ER) and pSer118ER evaluated by immunohistochemistry while no changes in pSer167ER expression were observed (PMID: 36269797). In selected tissues from these samples we observed that the staining intensity in trapped glands within the MFP-treated tumors did not follow a similar trend as that of tumor cells. Thus, the aim of this study was to evaluate the expression of hormone receptors and Ki67 in non-neoplastic human mammary glands (nnMG) adjacent to the PRA-H tumor tissue of postmenopausal patients, treated (n=8) or not (n=9) with MFP. No differences in PR, ER and pSer118ER expression were observed between MFP-treated nnMG and those from untreated patients. Notably, contrarily to what occurred in tumors, there was a significant decrease of pSer167ER expression (p=0.008) in the MFP-treated nnMG compared to the untreated glands, suggesting a selective modulation in the AKT-mediated activation of ER. Regarding the proliferative state of the nnMGs, there was a slight but significant increase (p=0.02) in Ki67 expression in MFP-treated vs. non-treated nnMG. Data regarding the effect of antiprogestins in normal mammary glands is limited and points, in premenopausal women, to a decrease in the Ki67 index after treatment. The basal quiescent status of nnMG in postmenopausal women may explain this slight stimulatory effect. In conclusion, our results show that MFP exerts a specific regulatory effect in PRA-H tumors that is not observed in the nnMG, probably due to the fact that nnMG have presumably equimolar levels of PRA and PRB. In addition, to counteract the possible stimulatory effect that MFP may induce on nnMG, the combination of MFP and tamoxifen treatment is suggested. Citation Format: Leo Saldain, Silvia Vanzulli, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Claudia Lanari, Paola Rojas. Differential regulation of hormone receptors and Ki67 in luminal breast carcinomas and tumor-adjacent mammary glands by mifepristone treatment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3994.

ObjectiveGuizhi Fuling Capsule (GZFL), a classic traditional Chinese medicine prescription, is often recommended for the treatment of uterine fibroids (UFs). However, the efficacy and safety of GZFL in combination with low-dose mifepristone (MFP) remains controversial.Materials and methodsWe searched eight literature databases and two clinical trial registries for randomized controlled trials (RCTs) of the efficacy and safety of GZFL combined with low-dose MFP in the treatment of UFs from database inception to April 24, 2022. Data analysis was performed using the Meta package in RStudio and RevMan 5.4. GRADE pro3.6.1 software was used for the assessment of evidence quality.ResultsTwenty-eight RCTs were included in this study, including a total of 2813 patients. The meta-analysis showed that compared with low-dose MFP alone, GZFL combined with low-dose MFP significantly reduced follicle stimulating hormone (p < 0.001), estradiol (p < 0.001), progesterone (p < 0.001), luteinizing hormone (p < 0.001), uterine fibroids volume (p < 0.001), uterine volume (p < 0.001), menstrual flow (p < 0.001) and increased clinical efficiency rate (p < 0.001). Meanwhile, GZFL combined with low-dose MFP did not significantly increase the incidence of adverse drug reactions compared with low-dose MFP alone (p = 0.16). The quality of the evidence for the outcomes ranged from “very low” to “moderate.”ConclusionThis study suggests that GZFL combined with low-dose MFP is more effective and safe in the treatment of UFs, and it is a potential treatment for UFs. However, due to the poor quality of the included RCTs formulations, we recommend a rigorous, high-quality, large-sample trial to confirm our findings.

Mechanoactivation has attracted considerable attention in the pharmaceutical sciences due to its ability to generate amorphous materials and solid-state synthetic products without the use of solvent. Although some studies have reported drug degradation during milling, no studies have systematically investigated the use of mechanoactivation in predicting drug degradation in the solid state. Thus, this work explores the autoxidation of drugs in the solid state by comilling amorphous mifepristone (MFP):polyvinylpyrrolidone vinyl acetate (PVPVA) and amorphous olanzapine (OLA):PVPVA. MFP was amorphized by ball milling and OLA by quench cooling techniques. Subsequently, comilling the amorphous drugs in the presence of a 10-fold weight ratio of PVPVA (the excipient containing reactive free radicals) was performed at several milling frequencies to identify the kinetics of mechano-autoxidation over milling durations. Overall, milling led to the degradation of up to 5% drug in the solid state. The autoxidation mechanism was confirmed by performing a stress study in the solution at 50 °C for 5 h, by using a 10 mM azo-bis(isobutyronitrile) (AIBN) as a stressing agent. By deconvoluting the effect of milling frequency and the energy on the extent and kinetics of milling-induced autoxidation of amorphous drugs, it was possible to fit an extended Arrhenius model that allowed extrapolation of mechanoactivated degradation rates (Km) to zero milling frequencies. Further, the autoxidation rates of drugs stored at high temperatures were observed to follow an Arrhenius behavior. A good degree of agreement was observed between the model predictions obtained by mechanoactivation (Km) to the reaction rates observed under accelerated temperatures. Additionally, the impact of adding an antioxidant (e.g., butylated hydroxytoluene) to the mixture during comilling was also examined. This study can be helpful in evaluating the stability of amorphous solids stored in accelerated (non-hermetic) conditions, in screening solid-state autoxidation propensity of drugs, and for the rational selection of antioxidants.

Non-genomic uterorelaxant actions of corticosteroid hormones in rats: An in vitro and in vivo study

BackgroundBreast cancer, the most diagnosed cancer, remains the second leading cause of cancer death in the United States, and excessive Progesterone (PRG) or Mifepristone (MIF) exposure may be at an increased risk for developing breast cancer. PRG exerts its cellular responses through signaling cascades involving classic, non-classic, or combined responses by binding to either classic nuclear PRG receptors (nPRs) or non-classic membrane PRG receptors (mPRs). Currently, the intricate balance and switch mechanisms between these two signaling cascades remain elusive. Three genes, CCM1-3, form the CCM signaling complex (CSC) which mediates multiple signaling cascades.MethodsUtilizing molecular, cellular, Omics, and systems biology approaches, we analyzed the relationship among the CSC, PRG, and nPRs/mPRs during breast cancer tumorigenesis.ResultsWe discovered that the CSC plays an essential role in coupling both classic and non-classic PRG signaling pathways by mediating crosstalk between them, forming the CmPn (CSC-mPRs-PRG-nPRs) signaling network. We found that mPR-specific PRG actions (PRG + MIF) play an essential role in this CmPn network during breast cancer tumorigenesis. Additionally, we have identified 4 categories of candidate biomarkers (9 intrinsic, 2 PRG-inducible, 1 PRG-repressive, 1 mPR-specific PRG-repressive, and 2 mPR-responsive) for Luminal-A breast cancers during tumorigenesis and have confirmed the prognostic application of RPL13 and RPL38 as intrinsic biomarkers using a dual validation method.ConclusionsWe have discovered that the CSC plays an essential role in the CmPn signaling network for Luminal-A breast cancers with identification of two intrinsic biomarkers.FPy3ZpQtYHZLtAbQQBYRNbVideo

Abstract Background: Preclinical data suggests that antiprogestins inhibit the growth of luminal breast carcinomas expressing higher levels of progesterone receptor isoform A (PRA) than isoform B (PRB). Thus, we designed a pre-surgical window of opportunity trial to determine the therapeutic effects of oral mifepristone (MFP) in 20 breast cancer patients selected by their high PRA/PRB isoform ratio (MIPRA; NCT02651844).Methods. MIPRA is an open-label, one-arm, prospective interventional study. After the selection process, 20 patients that met the inclusion criteria, with ER+, PRA/PRB&amp;gt;1.5 determined by Western blots, and total PR ≥50% determined by immunohistochemistry (IHC), were included for daily MFP treatment (200 mg/day p.o., 14 days). Core needle biopsies and surgical samples were formalin-fixed for IHC studies, and others were snap-frozen for further molecular studies. Besides, plasma samples were obtained for MFP dosing by LC-MS/MS. RNA was extracted from frozen tissue with a column-based method. The library for sequencing was constructed using SMART-Seq v4 Ultra Low Input RN from 8 paired samples in which tissue was available and passed the RNA quality control. Sequencing data was aligned with STAR and processed in R/Bioconductor. The counts matrix was obtained with featureCounts and differential expression paired analysis was performed with DESeq2. Gene set enrichment analysis (GSEA) was executed with the MSigDB collection.Results: A 49.62% decrease in Ki-67 staining was registered in all surgical specimens compared to baseline (p = 0.0003). Using the pre-specified response parameter (30% relative reduction) we identified 14/20 responders. Mifepristone was detected in all available plasma samples and the mean concentration was 308.33 ±57.91 ng/ml (716.71 ±134.62 nM). We conducted an RNA-seq analysis to explore changes at the transcript level. First, we conducted the study with all pairs of samples, without considering the response to MFP in Ki-67 studies. Unsupervised analysis showed the paired samples clustered together but neither the principal component analysis, nor the hierarchical clustering, showed any relevant cluster. The differential expression analysis identified 11 and 76 genes down- and up-regulated, respectively. We performed a GSEA based on KEGG databases and determined enriched pathways related to modulation of cell cycle and apoptosis. When the analysis was conducted with the REACTOME up-modulation of immune bioprocess and extracellular matrix re-modeling pathways such as degradation of extracellular matrix, activation of matrix metalloproteinases and collagen formation, were observed in the latter. Additionally, we observed down-modulation of pathways related to cell cycle such as DNA replication and synthesis, APC/C, and phase transition pathways. Interestingly, when we considered the tumors that responded to MFP according to Ki-67 data (n=4) and those that did not respond (n=4), we found that the non-responsive group shared some of the up and down modulated pathways as the responsive group.Conclusion: The results obtained in RNA-Seq data support the findings obtained by IHC indicating that MFP inhibits cell proliferation in luminal breast carcinomas with higher levels of PRA than PRB. The fact that MFP increased immune-related pathways is in line with previous preclinical data from our laboratory suggesting that MFP may prime this group of tumors for. further immune therapy. Interestingly, we found that some relevant pathways regarding inhibition of cell proliferation were also modulated in the non-responsive group suggesting that tumors in which a decrease in Ki-67 was not evident, may be still responding to MFP treatment. Ongoing analysis will determine changes in other markers that may help to further define MFP-responsive patients. Citation Format: Andres Elia, Martin Abba, Hugo Gass, Caroline A Lamb, Victoria T Fabris, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Ines Caillet Bois, Alejandra Castets, Silvia Lovisi, Marcos Liguori, Gabriela Pataccini, Maria Florencia Abascal, Virginia Novaro, Alfredo Molinolo, Silvia I Vanzulli, Paola Rojas, Claudia Lanari. Transcriptome modulation by mifepristone treatment in breast cancer patients with higher levels of progesterone receptor A than B [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-16-09.

Interventions that suppress hepatic gluconeogenesis from amino acids may be useful for improving glycemic control in diabetic patients. It was shown that administration of glucocorticoid receptor antagonist Mifepristone (MIF) leads to variously pronounced changes in the alanine-, aspartate-, tyrosine- aminotransferases (ALT, AST, TAT) activity in the liver of experimental animals. It has been suggested that this selective effect of MIF may be related to differences in the expression of the corresponding genes. The aim of the study was to investigate the gene expression and activity of ALT, AST and TAT in the liver of rats with streptozotocin-related diabetes (StD) under the long-term oral MIF administration. Male Wistar rats (n=48) with StD under the 10-days oral MIF administration were used. It was measured the activity of ALT, AST, TAT enzymes and relative expression of this genes in the liver of experimental animals. In rats with StD the gene expression of all three studied aminotransferases in the liver was statistically significantly increased and their activity was increased as well. MIF administration did not change the studied genes expression and enzymes activity to healthy rats and caused a decrease in expression of ALT and AST genes and activity of these enzymes to rats with StD. However, the expression of the TAT gene and the activity of this enzyme in the liver of rats with StD increased upon MIF administration in comparison with animals with StD. The introduction of MIF against the background of StD reduces the expression of genes and the activity of ALT and AST in the liver, what determine the transamination of amino acids to include them in gluconeogenesis, but increases the expression of genes and the activity of TAT, what determine the inclusion of tyrosine in the biogenic amines synthesis. The mechanisms of such selectivity require further study.

Effects of Fuke Qianjin Formula on hormones and their receptors and metabonomics study in uterine fibroids model rats

BackgroundUveal melanoma (UM), the most prevalent intraocular tumor in adults, is a highly metastatic and drug resistant lesion. Recent studies have demonstrated cytotoxic and anti-metastatic effects of the antiprogestin and antiglucocorticoid mifepristone (MF) in vitro and in clinical trials involving meningioma, colon, breast, and ovarian cancers. Drug repurposing is a cost-effective approach to bring approved drugs with good safety profiles to the clinic. This current study assessed the cytotoxic effects of MF in human UM cell lines of different genetic backgrounds.MethodsThe effects of incremental concentrations of MF (0, 5, 10, 20, or 40 μM) on a panel of human UM primary (MEL270, 92.1, MP41, and MP46) and metastatic (OMM2.5) cells were evaluated. Cells were incubated with MF for up to 72 h before subsequent assays were conducted. Cellular functionality and viability were assessed by Cell Counting Kit-8, trypan blue exclusion assay, and quantitative label-free IncuCyte live-cell analysis. Cell death was analyzed by binding of Annexin V-FITC and/or PI, caspase-3/7 activity, and DNA fragmentation. Additionally, the release of cell-free DNA was assessed by droplet digital PCR, while the expression of progesterone and glucocorticoid receptors was determined by quantitative real-time reverse transcriptase PCR.ResultsMF treatment reduced cellular proliferation and viability of all UM cell lines studied in a concentration-dependent manner. A reduction in cell growth was observed at lower concentrations of MF, with evidence of cell death at higher concentrations. A significant increase in Annexin V-FITC and PI double positive cells, caspase-3/7 activity, DNA fragmentation, and cell-free DNA release suggests potent cytotoxicity of MF. None of the tested human UM cells expressed the classical progesterone receptor in the absence or presence of MF treatment, suggesting a mechanism independent of the modulation of the cognate nuclear progesterone receptor. In turn, all cells expressed non-classical progesterone receptors and the glucocorticoid receptor.ConclusionThis study demonstrates that MF impedes the proliferation of UM cells in a concentration-dependent manner. We report that MF treatment at lower concentrations results in cell growth arrest, while increasing the concentration leads to lethality. MF, which has a good safety profile, could be a reliable adjuvant of a repurposing therapy against UM.

Selective progesterone receptor blockade prevents BRCA1-associated mouse mammary tumors through modulation of epithelial and stromal genes

Introduction: Mifepristone (MFP) aka RU-486/Korlym is a synthetic steroid analog originally developed in 1980 as an abortifacient that is now used in the management of Cushing’s syndrome (CS). It is both a progesterone (PG) and glucocorticoid (GC) receptor blocker. CS is often associated with reproductive functional anomalies including hypogonadism, menstrual irregularities and infertility. Due to its mode of action, measurement of serum PG and/or cortisol in patients on MFP are inaccurate indices of systemic PG and/or GC deficiency or excess. However, the potential impact of MFP use on other serum steroid assays has not been widely studied. We report the case of a 55 yr old man on treatment with MFP for adrenal CS found to have striking artefactual changes in serum androgen and estrogen levels. Case Summary: A 55 yr old African American man was referred with poorly controlled type 2 diabetes, hypertension, hyperlipidemia, obesity and untreated hypogonadism. He had a 3.2cm left adrenal incidentaloma associated with adrenal CS and he chose medical management rather than surgery. Upon starting MFP at 300mg QD serum total estrogen (by radio-immunoassay; RIA) and estradiol (by chemiluminescence immunoassay; CIA) were markedly elevated while serum total, free, bioavailable testosterone and dihydrotestosterone were all markedly reduced. His HBA1c, weight and energy levels improved on MFP despite these findings. The serum steroid levels normalized to pre-treatment levels after stopping MFP for ~ 4weeks but the changes recurred after restarting therapy. After MFP dose escalation to 300mg BID the serum steroid levels normalized after stopping MFP for ~ 6 weeks. The artefactual low testosterone levels also occured with measurement by equilibrium dialysis but “normal accurate” results were obtained when measured by liquid chromatography-Tandem mass spectrometry (LC-TMS). He remains on MFP 300mg BID without need for androgen repletion. Discussion: With increased use of MFP for CS, indices for tracking its clinical and biochemical effects assume great importance. There are few reports of the possible effects of MFP on estrogen and testosterone serum assays despite its touted low cross reactivity with sex steroids. Our case suggests that the significance, extent and prevalence of artefactual changes on serum sex steroid assays may be underestimated and under- appreciated. Conclusions: Our case of wide disparities in serum estrogen and androgen measures in a patient on MFP indicates that caution needs to be exercised in the interpretation of such results in patients on current MFP therapy. Our clinical observations suggest depending on the dose that a wash out period of 4–6 weeks is required to ensure accurate measures. Studies to ascertain the prevalence of this artefactual effect are needed and it appears testosterone measurement by LC-TMS obviates the testosterone assay artefact.

Mifepristone + misoprostol cost effective for missed miscarriage in the UK

The role of active antitumor immunity in hormone receptor-positive (HR+) breast cancer has been historically underlooked. The aim of this study was to determine the contribution of the immune system to antiprogestin-induced tumor growth inhibition using a hormone-dependent breast cancer model. BALB/c-GFP+ bone marrow (BM) cells were transplanted into immunodeficient NSG mice to generate an immunocompetent NSG/BM-GFP+ (NSG-R) mouse model. Treatment with the antiprogestin mifepristone (MFP) inhibited growth of 59-2-HI tumors with similar kinetics in both animal models. Interestingly, MFP treatment reshaped the tumor microenvironment, enhancing the production of proinflammatory cytokines and chemokines. Tumors in MFP-treated immunocompetent mice showed increased infiltration of F4/80+ macrophages, natural killer, and CD8 T cells, displaying a central memory phenotype. Mechanistically, MFP induced immunogenic cell death (ICD) in vivo and in vitro, as depicted by the expression and subcellular localization of the alarmins calreticulin and HMGB-1 and the induction of an ICD gene program. Moreover, MFP-treated tumor cells efficiently activated immature dendritic cells, evidenced by enhanced expression of MHC-II and CD86, and induced a memory T-cell response, attenuating tumor onset and growth after re-challenge. Finally, MFP treatment increased the sensitivity of HR+ 59-2-HI tumor to PD-L1 blockade, suggesting that antiprogestins may improve immunotherapy response rates. These results contribute to a better understanding of the mechanisms underlying the antitumor effect of hormonal treatment and the rational design of therapeutic combinations based on endocrine and immunomodulatory agents in HR+ breast cancer. SIGNIFICANCE: Antiprogestin therapy induces immunogenic tumor cell death in PRA-overexpressing tumors, eliciting an adaptive immune memory response that protects mice from future tumor recurrence and increases sensitivity to PD-L1 blockade. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/5/1375/F1.large.jpg.

Abstract Background: Different antiprogestins have been clinically evaluated in gynecological andbreast cancers. Mifepristone (MFP), as well as onapristone and telapristone acetate, showedpartial responses in breast cancer clinical trials. Preclinical data indicates that antiprogestinsinhibit cell proliferation of luminal breast carcinomas expressing higher levels of progesteronereceptor isoform A (PRA) than those of isoform B (PRB) evaluated by western blots (WB). Thus,we designed a pre-surgical window trial to determine the therapeutic effects of oral MFP oncell proliferation and on differential gene expression in 20 breast cancer patients selected bytheir high PRA/PRB isoform ratio.Methods. MIPRA is an open-label, one-arm, prospective interventional study (NCT02651844).We interviewed 140 naive breast cancer patients and 133 accepted to participate. Four coreultrasound-guided biopsies were performed, two were formalin-fixed for diagnosis, ER, PR,HER2, and Ki67 evaluation and two were snap-frozen for WB and molecular studies. Patientsthat met the inclusion criteria, with ER+, PRA/PRB&amp;gt;1.5 and total PR ≥50% determined by WBand immunohistochemistry (IHC), respectively, were included for MFP treatment. Plasma wasobtained before and after treatment for future studies. Patients were treated with oral MFP(200 mg/day) for 14 days before surgery which was performed on day 15. Clinical examinationwas performed at days 7 and 14 to register possible adverse effects and to measure tumorsize. During surgery, samples were formalin-fixed for IHC studies, and others were snap-frozenfor further molecular studies. One patient had a bilateral breast cancer, and both tumorsmatched with the inclusion criteria and were included. The primary endpoint was Ki67labeling, comparing diagnostic core needle biopsy to post-therapy surgical specimens.Considering previous studies performed with tamoxifen, we pre-specified that 30% of relativereduction in Ki67 would be considered as a positive response. Differences in Ki67 expressionwere quantitated by an expert pathologist counting at least ten 40x fields per slide. Theseresults are currently being validated by a second pathologist. One patient, with a core biopsywith less than 500 total cells, was excluded. Ongoing experiments include secondary and otherendpoints: comparison of apoptotic, proliferative and hormone receptor markers by IHC,measurement of MFP plasma levels and, RNAseq analysis in samples pre- and post-treatment. Ki67 changes from baseline were tested with paired Wilcoxon matched-pairssigned-rank test.Results: The median (range) Ki67 value of biopsies was 11.87% (2.70- 34.56) and for surgicalspecimens was 6.45% (0.48-23.77). A 45.67% of decrease in the median % Ki67 (41.63%comparing the arithmetic mean values and 50.83% comparing the geometric mean values) wasregistered in all surgical specimens compared to baseline (p= 0.003). Using the pre-specifiedresponse parameter (30% relative reduction in Ki67), we identified 15/20 (75%) responders.Considering only responsive tumors, a 49.87% decrease in the median % Ki67 (50.83%,arithmetic mean; 62.34% geometric mean) was observed (p&amp;lt;0.0001) between baseline andsurgical specimens. In those cases with the highest response, the decrease in Ki-67 wasaccompanied by a decrease in tumor volume (ultrasound measurements).Conclusion: Our results show that MFP treatment may be effective in patients showing a highPRA/PRB ratio. The magnitude of the inhibition was similar or higher to that reported fortamoxifen in ER+ breast cancer patients in short-term treatment studies. Ongoing analysis willdetermine if there are changes in other markers that may help to further define MFP-responsive patients. Citation Format: Andres Elia, Silvia I Vanzulli, Hugo Gass, Caroline A Lamb, Victoria T Fabris, Paula Martinez Vazquez, Javier Burruchaga, Eunice Spengler, Ines Caillet Bois, Alejandra Castets, Silvia Lovisi, Marcos Liguori, Gabriela Pataccini, M Florencia Abascal, Virginia Novaro, Gabriela Acosta Haab, Alfredo Molinolo, Paola Rojas, Claudia Lanari. Mipra, a window of opportunity study evaluating mifepristone treatment for postmenopausal breast cancer patients with higher levels of progesterone receptor isoform a than b [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-35.