Ulipristal Acetate Inhibits Progesterone Receptor Isoform A-Mediated Human Breast Cancer Proliferation and BCl2-L1 Expression

Ulipristal-temozolomide-hydroxyurea combination for glioblastoma: in-vitro studies

BACKGROUND

Glioblastoma multiforme (GBM) is a brain malignancy with worst survival. Low dose progesterone stimulates GBM growth, while progesterone receptor (PR)-antagonist mifepristone was shown to reduce growth and to enhance temozolomide sensitivity in GBM cells. Mifepristone is not available in all countries due to ethical reasons and may cause adrenal insufficiency and pelvic infections. Ulipristal is also a PR-antagonist used in treatment of uterine leiomyomas with higher biosafety. Ulipristal is demonstrated to suppress growth of breast cancer, yet it is not tested as yet whether it can also block growth and sensitize to temozolomide in glioblastoma as it was previously shown with mifepristone. Our first aim was to detect whether ulipristal exerts antiproliferative and chemotherapy-sensitizing effects in glioblastoma. Hydroxyurea inhibits DNA replication via blocking ribonucleotide reductase (RR) and it was demonstrated to increase temozolomide antineoplasticity in GBM. Progesterone receptor-activation in the uterus enhances RR transcription. Hence, we have hypothesized that PR-inactivation with ulipristal would further enhance hydroxyurea antineoplasticity by shutting down DNA synthesis mechanisms through further suppression of RR. Lastly, there exists no study as yet whether ulipristal, hydroxyurea and temozolomide could exert ternary antineoplastic efficacy, which was our last aim to define.

METHODS

To reveal interactions between ulipristal, hydroxyurea and temozolomide, we treated human U251 GBM cell line with these agents alone and in combination and measured cell proliferation, total antioxidant capacity (TAC) and total oxidant status (TOS) in conditioned medium and cellular cytokine gene expressions.

RESULTS

All agents significantly reduced cell proliferation significantly, yet the most significant decrease of GBM cells occurred with the triple drug combination at the 96th hour. All agents significantly decreased TAC and increased TOS in culture media, which was mostly relevant for the triple combination at the 96th hour. All these three agents tend to reduce the expression of immunosuppressive and/or GBM-growth stimulating cytokines TGF-β, IL-10 and IL-17 while increasing the expression of GBM-growth suppressing cytokine IL-23.

CONCLUSIONS

Reproposal of these agents in treatment of GBM would be a plausible approach if future studies prove their efficacy.

Antiprogestins for breast cancer treatment: We are almost ready

The development of antiprogestins was initially a gynecological purpose. However, since mifepristone was developed, its application for breast cancer treatment was immediately proposed. Later, new compounds with lower antiglucocorticoid and antiandrogenic effects were developed to be applied to different pathologies, including breast cancer. We describe herein the studies performed in the breast cancer field with special focus on those reported in recent years, ranging from preclinical biological models to those carried out in patients. We highlight the potential use of antiprogestins in breast cancer prevention in women with BRCA1 mutations, and their use for breast cancer treatment, emphasizing the need to elucidate which patients will respond. In this sense, the PR isoform ratio has emerged as a possible tool to predict antiprogestin responsiveness. The effects of combined treatments of antiprogestins together with other drugs currently used in the clinic, such as tamoxifen, CDK4/CDK6 inhibitors or pembrolizumab in preclinical models is discussed since it is in this scenario that antiprogestins will be probably introduced. Finally, we explain how transcriptomic or proteomic studies, that were carried out in different luminal breast cancer models and in breast cancer samples that responded or were predicted to respond to the antiprogestin therapy, show a decrease in proliferative pathways. Deregulated pathways intrinsic of each model are discussed, as well as how these analyses may contribute to a better understanding of the mechanisms involved.

Ulipristal acetate, a selective progesterone receptor modulator, induces cell death via inhibition of STAT3/CCL2 signaling pathway in uterine sarcoma

Ulipristal acetate (UPA) is a selective progesterone receptor modulator and is used for the treatment of uterine leiomyoma (a benign tumor). Uterine sarcoma which is highly malignant cancer with a poor prognosis is clinically resembled with uterine leiomyoma. There has been no experimental research on the effect of UPA on uterine sarcoma. In this study, we examined the efficacy of UPA in uterine sarcoma with in vitro and in vivo animal models. Cytotoxicity of UPA was determined in uterine sarcoma cell lines (MES-SA, SK-UT-1, and SK-LMS-1). Apoptotic genes and signaling pathways affected by UPA were analyzed by complementary DNA (cDNA) microarray of uterine sarcoma cell lines and western blot, respectively. An in vivo efficacy of UPA was examined with uterine sarcoma cell line- and patient-derived xenograft (PDX) mice models. UPA inhibited cell growth in uterine sarcoma cell lines and primary culture cells from a PDX mouse (PDX-C). cDNA microarray analysis revealed that CCL2 was highly down-regulated by UPA. Phosphorylation and the total expression of STAT3 were inhibited by UPA. UPA also inhibited CCL2 and STAT3 in PDX-C. The inhibitory effect of UPA had not changed in the overexpression of PR and treatment of progesterone. In vivo efficacy studies with cell line-derived xenografts and a PDX model with leiomyosarcoma, a typical uterine sarcoma, demonstrated that UPA significantly decreased tumor growth. UPA had significant anti-tumor effects in uterine sarcoma through the inhibition of STAT3/CCL2 signaling pathway and might be a potential therapeutic agent to treat this disease.

Progesterone receptor isoform ratios influence the transcriptional activity of progestins via the progesterone receptor

Progestins (synthetic progestogens) are progesterone receptor (PR) ligands used globally by women in both hormonal contraception and menopausal hormone therapy. Although four generations of unique progestins have been developed, studies seldom distinguish between the activities of progestins via the two functionally distinct PR isoforms, PR-A and PR-B. Moreover, not much is known about the action of progestins in breast cancer tumors where PR-A is mostly overexpressed relative to PR-B. Understanding progestin action in breast cancer is crucial since the clinical use of some progestins has been associated with an increased risk of developing breast cancer. This study directly compared the agonist activities of selected progestins from all four generations for transactivation and transrepression via either PR-A or PR-B, and when PR-A and PR-B were co-expressed at ratios comparable to those detected in breast cancer tumors. Comparative dose-response analysis showed that earlier generation progestins mostly displayed similar efficacies for transactivation on a minimal progesterone response element via the PR isoforms, while most of the 4th generation progestins, similar to the natural progestogen, progesterone (P4), were more efficacious via PR-B. Most of the progestogens were however more potent via PR-A. We are the first to show that the efficacies of the selected progestogens via the individual PR isoforms were generally decreased when PR-A and PR-B were co-expressed, irrespective of the ratio of PR-A:PR-B. While the potencies of most progestogens via PR-B were enhanced when the ratio of PR-A relative to PR-B was increased, those via PR-A were minimally influenced. This study is also the first to report that all progestogens evaluated, except 1st generation medroxyprogesterone acetate and 4th generation drospirenone, displayed similar agonist activity for transrepression via PR-A and PR-B on a minimal nuclear factor kappa B containing promoter. Moreover, we showed that the progestogen activity for transrepression was significantly increased when PR-A and PR-B were co-expressed. Taken together, our results highlight that PR agonists (progestogens) do not always display the same activity via PR-A and PR-B, or when PR-A and PR-B are co-expressed at ratios mimicking those found in breast cancer tumors. These results suggest that biological responses are progestogen- and PR isoform-dependent and may differ in target tissues expressing varying PR-A:PR-B ratios.

Topical transdermal chemoprevention of breast cancer: where will nanomedical approaches deliver us?

Despite the high incidence of breast cancer, there are few pharmacological prevention strategies for the high-risk population and those that are available have low adherence. Strategies that deliver drugs directly to the breasts may increase drug local concentrations, improving efficacy, safety and acceptance. The skin of the breast has been proposed as an administration route for local transdermal therapy, which may improve drug levels in the mammary tissue, due to both deep local penetration and percutaneous absorption. In this review, we discuss the application of nanotechnology-based strategies for the delivery of well established and new agents as well as drug repurposing using the topical transdermal route to improve the outcomes of preventive therapy for breast cancer.

Brain reactivity during aggressive response in women with premenstrual dysphoric disorder treated with a selective progesterone receptor modulator

Premenstrual dysphoric disorder (PMDD) is a psychiatric condition characterized by late luteal phase affective, cognitive, and physical impairment. The disorder causes significant suffering in about 5% of women in their reproductive age. Altered sensitivity of cognitive-affective brain circuits to progesterone and its downstream metabolite allopregnanolone is suggested to underlie PMDD symptomatology. Core mood symptoms include irritability and anger, with aggression being the behavioral outcome of these symptoms. The present study sought to investigate the neural correlates of reactive aggression during the premenstrual phase in women with PMDD, randomized to a selective progesterone receptor modulator (SPRM) or placebo. Self-reports on the Daily Record of Severity of Problems were used to assess PMDD symptoms and gonadal hormone levels were measured by liquid chromatography tandem mass spectrometry. Functional magnetic resonance imaging was performed in 30 women with PMDD, while performing the point subtraction aggression paradigm. Overall, a high SPRM treatment response rate was attained (93%), in comparison with placebo (53.3%). Women with PMDD randomized to SPRM treatment had enhanced brain reactivity in the dorsal anterior cingulate cortex and dorsomedial prefrontal cortex during the aggressive response condition. The fronto-cingulate reactivity during aggressive responses depended on treatment, with a negative relationship between brain reactivity and task-related aggressiveness found in the placebo but not the SPRM group. The findings contribute to define the role of progesterone in PMDD symptomatology, suggesting a beneficial effect of progesterone receptor antagonism, and consequent anovulation, on top-down emotion regulation, i.e., greater fronto-cingulate activity in response to provocation stimuli.

A 12-month extension study to evaluate the safety and efficacy of asoprisnil in women with heavy menstrual bleeding and uterine fibroids

STUDY QUESTION

What is the safety and efficacy profile during long-term (12–24 months) uninterrupted treatment with the selective progesterone receptor modulator asoprisnil, 10 and 25 mg in women with heavy menstrual bleeding (HMB) associated with uterine fibroids?

SUMMARY ANSWER

Uninterrupted treatment with asoprisnil should be avoided due to endometrial safety concerns and unknown potential long-term consequences.

WHAT IS KNOWN ALREADY

Asoprisnil was well tolerated in shorter-term studies and effectively suppressed HMB and reduced fibroid volume.

STUDY DESIGN, SIZE, DURATION

Women with uterine fibroids who had previously received placebo (n = 87) or asoprisnil 10 mg (n = 221) or 25 mg (n = 215) for 12 months in two double-blind studies entered this randomized uncontrolled extension study and received up to 12 additional months of treatment followed by 6 months of post-treatment follow-up. Women who previously received placebo were re-randomized to either asoprisnil 10 or 25 mg for the extension study. This report focuses on the 436 women who received asoprisnil in the double-blind studies and this extension study. Results for women who previously received placebo in the double-blind studies are not described.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women ≥18 years of age who completed a 12-month, double-blind, placebo-controlled study, had estradiol levels indicating that they were not menopausal and had no endometrial hyperplasia or other significant endometrial pathology were eligible. The safety endpoints were focused on endometrial assessments. The composite primary efficacy endpoint was the proportion of women who demonstrated a response to treatment by meeting all three of the following criteria at the final month for participants who prematurely discontinued or at month 12 for those who completed the study: a reduction from initial baseline to final visit of ≥50% in the menstrual pictogram score, hemoglobin concentration ≥11 g/dl or an increase of ≥1 g/dl from initial baseline at the final visit, and no surgical or invasive intervention for uterine fibroids. Other efficacy endpoints included rates for amenorrhea and suppression of bleeding, changes in fibroid and uterine volume and changes in hematologic parameters. No statistical tests were planned or performed for this uncontrolled study.

MAIN RESULTS AND ROLE OF CHANCE

Imaging studies revealed a progressive increase in endometrial thickness and cystic changes that frequently prompted invasive diagnostic procedures. Endometrial biopsy results were consistent with antiproliferative effects of asoprisnil. Two cases of endometrial cancer were diagnosed. At the final month of this extension study (total duration of uninterrupted treatment up to 24 months), the primary efficacy endpoint was achieved in 86 and 92% of women in the asoprisnil 10- and 25-mg groups, respectively. During each month of treatment, amenorrhea was observed in the majority of women (up to 77 and 94% at 10 and 25 mg, respectively). There was a progressive, dose-dependent decrease in the volume of the primary fibroid with asoprisnil 10 and 25 mg (−55.7 and −75.2% median decrease, respectively, from baseline [i.e. the beginning of the placebo-controlled study] to month 12 [cumulative months 12–24] of this extension study). These effects were associated with improvements in quality of life measures.

LIMITATIONS, REASONS FOR CAUTION

This study was uncontrolled, which limits the interpretation of safety and efficacy findings. The study also had multiple protocol amendments with the addition of diagnostic procedures and, because no active comparator was included, the potential place of asoprisnil in comparison to therapies such as GnRH agonists and surgery cannot be determined.

WIDER IMPLICATIONS OF THE FINDINGS

Long-term, uninterrupted treatment with asoprisnil leads to prominent cystic endometrial changes that are consistent with the ‘late progesterone receptor modulator’ effects, which prompted invasive diagnostic procedures, although treatment efficacy is maintained. Although endometrial cancers were uncommon during both treatment and follow-up, these findings raise concerns regarding endometrial safety during uninterrupted long-term treatment with asoprisnil. This study shows that uninterrupted treatment with asoprisnil should be avoided due to safety concerns and unknown potential long-term consequences.

STUDY FUNDING/COMPETING INTEREST(S)

AbbVie Inc. (prior sponsor, TAP Pharmaceutical Products Inc.) sponsored the study and contributed to the design and conduct of the study, data management, data analysis, interpretation of the data and the preparation and approval of the manuscript. Financial support for medical writing and editorial assistance was provided by AbbVie Inc. M. P. Diamond received research funding for the conduct of the study paid to the institution and is a consultant to AbbVie. He is a stockholder and board and director member of Advanced Reproductive Care. He has also received funding for study conduct paid to the institution for Bayer and ObsEva. E. A. Stewart participated as a site investigator in the phase 2 study of asoprisnil and served as a consultant to TAP Pharmaceuticals during the time of design and conduct of the studies while on the faculty of Harvard Medical School and Brigham and Women’s Hospital, Boston, MA. In the last 3 years, she has received support from National Institutes of Health grants HD063312, HS023418 and HD074711. She has served as a consultant for AbbVie Inc., Allergan, Bayer HealthCare AG and Myovant for consulting related to uterine leiomyoma and to Welltwigs for consulting related to infertility. She has received royalties from UpToDate and the Med Learning Group. A.R.W. Williams has acted as a consultant for TAP Pharmaceutical Products Inc. and Repros Therapeutics Inc. He has current consultancies with PregLem SA, Gedeon Richter, HRA Pharma and Bayer. B.R. Carr has served as consultant and received research funding from AbbVie Inc. and Synteract (Medicines360). E.R. Myers has served as consultant for AbbVie Inc., Allergan and Bayer. R.A. Feldman received compensation for serving as a principal investigator and participating in the conduct of the trial. W. Elger was a co-inventor of several patents related to asoprisnil.

C. Mattia-Goldberg is a former employee of AbbVie Inc. and owns AbbVie stock or stock options. B.M. Schwefel and K. Chwalisz are employees of AbbVie Inc. and own AbbVie stock or stock options.

TRIAL REGISTRATION NUMBER

NCT00156195 at clinicaltrials.gov.

Resistance of primary breast cancer cells with enhanced pluripotency and stem cell activity to sex hormonal stimulation and suppression

Female sex steroid hormones have a fundamental role in breast cancer. Meanwhile, current evidence supports the contribution of breast cancer stem cells in carcinogenesis, metastasis, and resistance to cytotoxic chemotherapy. Nevertheless, the interaction between breast cancer stem cells with sex hormones or key hormonal antagonists remains elusive.

OBJECTIVE

To investigate the effect of diverse sex hormonal stimulation and suppression regimens on the proliferation of a primary human breast cancer cells with stem cell activity.

METHODS

Cells were exposed to estradiol, progesterone, letrozole, ulipristal acetate, or a combination of ulipristal acetate-letrozole, continually for 6 months. Additionally, nanoparticle-linked letrozole and ulipristal acetate formulations were included in a subsequent short-term exposure study. Phenotypic, pathologic, and functional characteristics of unexposed cells were investigated.

RESULTS

The proliferation of breast cancer cells was comparable among all hormonal stimulation and suppression groups (P= 0.8). In addition, the nanoparticle encapsulated hormonal antagonists were not able to overcome the observed resistance of cells. Cell characterization showed a mesenchymal-like phenotype overexpressing three master pluripotency markers (Oct 4, SOX2, and Nanog), and 92% of cells were expressing ALDH1A1. Notably, the CD44 ^high/CD24 ^low cell population presented only 0.97%-5.4% over repeat analyses. Most cells lacked the expression of mesenchymal markers; however, they showed differentiation into osteogenic and adipogenic lineages. Upon transfer to serum-free culture, the long-term maintained mesenchymal-like cancer cells showed remarkable morphologic plasticity as they switched promptly into an epithelial-like phenotype with significant mammosphere formation capacity (P= 0.008).

CONCLUSION

Breast cancer cells can develop a pluripotent program with enhanced stemness activity that may together contribute to universal resistance to sex hormonal stimulation or deprivation. Isolation and characterization of patient-derived breast cancer stem cells in large clinical studies is therefore crucial to identify new targets for endocrine therapies, potentially directed towards stemness and pluripotency markers. Such direction may help overcoming endocrine resistance and draw attention to breast cancer stem cells' behaviour under endogenous and exogenous sex hormones throughout a woman's reproductive life.

Efficacy, safety and recurrence of new progestins and selective progesterone receptor modulator for the treatment of endometriosis: a comparison study in mice

BACKGROUND

Current medical treatments for endometriosis are very limited. Progestin and selective progesterone receptor modulators (SPRM) are developed but their efficacy, safety, mechanism and recurrence in endometriosis are not fully studied.

METHODS

In order to compare therapeutic, side effects and therapeutic actions of Esmya, Duphaston and Dienogest in endometriosis. Experimental endometriosis was induced by either intraperitoneal or subcutaneous mouse endometrium transplantation. Lesion size, weight and histology at the end of intervention were compared. Expression of related markers in the endometriotic lesions were examined. Body, uterus and ovary weights, endometrial glands and thickness (ETI), and follicle count were measured. For recurrent study, lesion growth before and after intervention was monitored.

RESULTS

After Esmya, Duphaston, Dienogest treatment, lesion size and weight were significantly decreased. Proliferation Pcna expression was significantly decreased in all groups, but proliferation cells were significantly decreased only in Duphaston group. Apoptosis Mapk1 expression and TUNEL-positive cells were significantly increased in Duphaston group. Adhesion Mmp2 and Itgavβ3 expression were significantly increased in Esmya group. Plau, Hif1α and Vegfa expression, peritoneal fluid PGE2 levels, and ERα and ERβ expression were not affected; while PR expression was significantly lower in all groups. Endometrial gland count in uterus was significantly increased in Dienogest group, ETI was significantly decreased in Duphaston group, and AFC were significantly increased in Esmya group. Upon treatment cessation, lesion growth rebound quickly in Dienogest and Duphaston groups, but slowly in Esmya group.

CONCLUSION

Esmya, Duphaston and Dienogest are effective anti-endometriosis drugs targeting proliferation, apoptosis and adhesion. Esmya, Duphaston and Dienogest are all well tolerable, although endometrial glandular hyperplasia was found in Dienogest, endometrial atrophy in Duphaston, follicle accumulation in Esmya.

Ulipristal Acetate Interferes With Actin Remodeling Induced by 17β-Estradiol and Progesterone in Human Endometrial Stromal Cells

Ulipristal acetate (UPA) is a selective progesterone receptor modulator (SPRM) used for emergency contraception and for the medical management of symptomatic uterine fibroids (UF). Treatment with UPA turns in amenorrhea and UF volume reduction. Treatment with UPA is associated with the frequent development of benign, transitory endometrial changes known as SPRM-associated endometrial changes (PAECs). Why PAECs develop and their biological or cellular basis is unknown. Sex steroids, including estrogen and progesterone, are established modulators of the actin cytoskeleton in various cells, including endometrial cells. This explains several morphological and functional changes in endometrial cells. We thus hypothesized that UPA may alter the appearance of the endometrium by interfering with the actions of 17β-estradiol (E2) or progesterone (P4) on actin dynamics. We isolated and cultured human endometrial stromal cells (ESC) from endometrial biopsies from healthy fertile women. Treatment with E2 or P4 stimulated visible actin rearrangements with actin remodeling toward the membrane. Activation through phosphorylation of the actin regulatory proteins, Moesin, and focal adhesion kinase (FAK), hacked actin remodeling induced by E2 and P4. Membrane re-localization of Paxillin and Vinculin were also induced by E2 and P4, showing the formation of focal adhesion complexes. All these E2 and P4 actions were inhibited by co-treatment with UPA, which was otherwise inactive if given alone. The cytoskeletal changes induced by E2 and P4 turned into increased motility of ESC, and UPA again blocked the actions E2 and P4. In conclusion, we find that UPA interferes with the cytoskeletal actions of E2 and P4 in ESC. This finding helps understanding the mode of actions of SPRMs in the endometrium and may be relevant for other potential clinical applications of UPA.

A Network-Based Integrative Workflow to Unravel Mechanisms Underlying Disease Progression

Unraveling mechanisms underlying diseases has motivated the development of systems biology approaches. The key challenges for the development of mathematical models and computational tool are (1) the size of molecular networks, (2) the nonlinear nature of spatio-temporal interactions, and (3) feedback loops in the structure of interaction networks. We here propose an integrative workflow that combines structural analyses of networks, high-throughput data, and mechanistic modeling. As an illustration of the workflow, we use prostate cancer as a case study with the aim of identifying key functional components associated with primary to metastasis transitions. Analysis carried out by the workflow revealed that HOXD10, BCL2, and PGR are the most important factors affected in primary prostate samples, whereas, in the metastatic state, STAT3, JUN, and JUNB are playing a central role. The identified key elements of each network are validated using patient survival analysis. The workflow presented here allows experimentalists to use heterogeneous data sources for the identification of diagnostic and prognostic signatures.

Progesterone Receptor Isoforms, Nuclear Corepressor-1 and Steroid Receptor Coactivator-1 and B-Cell Lymphoma 2 and Akt and Akt Phosphorylation Status in Uterine Myomas after Ulipristal Acetate Treatment: A Systematic Immunohistochemical Evaluation

OBJECTIVE

To investigate whether ulipristal acetate (UPA) treatment modifies the expression of progesterone receptor (PR), its nuclear cofactors steroid receptor coactivator-1 (SRC1) and nuclear corepressor-1 (NCoR1), prosurvival factor B-cell lymphoma 2 (Bcl-2), and Akt in uterine myomas.

PATIENTS

Prospective study of 59 women with symptomatic myomas undergoing myomectomy. Forty-two patients were treated preoperatively with UPA; the remaining 17 were not and they served as controls.

METHOD

Tissue microarrays were obtained from surgical specimens and immunohistochemistry was performed. Blinded quantification of expression of PR (PR-A vs. PR-B), coactivator SRC1 and corepressor NCoR1, and prosurvival factor Bcl-2, and Akt and evaluation of Akt phosphorylation levels.

RESULTS

Compared with the control group, UPA does not alter PR protein levels or expression patterns in myomas, and the PR-A/PR-B ratio was similar, as well as cytoplasmic or nuclear expression of cofactors SRC1 and NCoR1. Bcl-2 was heterogeneously expressed throughout the samples and no significant modification in expression was evidenced. No significant difference was found in Akt expression and phosphorylation between treated and untreated myomas.

CONCLUSION

This study did not find any significant change in the expression of the studied factors in myomas after UPA exposure. In conclusion, various theories on myomas cells proposed on the basis of in vitro studies are not supported in vivo.

Progesterone-mediated angiogenic activity of endothelial progenitor cell and angiogenesis in traumatic brain injury rats were antagonized by progesterone receptor antagonist

OBJECTIVES

Progesterone (P4) has the potential therapeutic effects for traumatic brain injury (TBI) whose recovery depended on the enhanced angiogenesis. Endothelial progenitor cell (EPC) plays an essential role in vascular biology. We previously demonstrated that P4 administration improved circulating EPC level and neurological recovery of rat with TBI. Here, we hypothesized that P4 augmented angiogenic potential of EPC and the angiogenesis-related neurorestoration after TBI through classical progesterone receptor (PR).

MATERIALS AND METHODS

EPC derived from rats were stimulated with graded concentrations (0, 10^-10 , 10^-9 , 5 × 10^-9 , 10^-8 , 10^-7  mol/L) of P4 or 10^-6  mol/L ulipristal acetate (UPA, a PR antagonist). Male rats were subjected to cortical impact injury and treated with (i) DMSO (dimethyl sulfoxide), (ii) P4 and (iii) P4 and UPA.

RESULTS

It showed that P4 improved the angiogenic potential of EPC, including tube formation, adhesion, migration and vascular endothelial growth factor secretion, in a dose-dependent fashion with the maximal effect achieved at 10^-9  mol/L P4. High concentration (10^-7  mol/L) of P4 impaired the angiogenic potential of EPC. Notably, 10^-6  mol/L UPA antagonized the stimulatory effects of 10^-9  mol/L P4. After administrating P4, a significant improvement of neurological function and the restoration of the leaked blood-brain barrier were observed as well as a reduction of the brain water content. Both vessel density and expression of occludin of vessels were increased. When UPA was administered with P4, the neural restoration and angiogenesis were all reversed. Western blot showed that 10^-9  mol/L P4 increased the content of PRA and PRB of EPC, while 10^-7  mol/L P4 reduced the content of both PR isoforms, but there was no change found in the TBI rats.

CONCLUSIONS

It may suggest that P4-mediated angiogenic activity of EPC and angiogenesis in TBI rats were antagonized by PR antagonist.

Progesterone Receptor Isoform Ratio: A Breast Cancer Prognostic and Predictive Factor for Antiprogestin Responsiveness

Background

Compelling evidence shows that progestins regulate breast cancer growth. Using preclinical models, we demonstrated that antiprogestins are inhibitory when the level of progesterone receptor isoform A (PR-A) is higher than that of isoform B (PR-B) and that they might stimulate growth when PR-B is predominant. The aims of this study were to investigate ex vivo responses to mifepristone (MFP) in breast carcinomas with different PR isoform ratios and to examine their clinical and molecular characteristics.

Methods

We performed human breast cancer tissue culture assays (n = 36) to evaluate the effect of MFP on cell proliferation. PR isoform expression was determined by immunoblotting (n = 282). Tumors were categorized as PRA-H (PR-A/PR-B ≥ 1.2) or PRB-H (PR-A/PR-B ≤ 0.83). RNA was extracted for Ribo-Zero-Seq sequencing to evaluate differentially expressed genes. Subtypes and risk scores were predicted using the PAM50 gene set, the data analyzed using The Cancer Genome Atlas RNA-seq gene analysis and other publicly available gene expression data. Tissue microarrays were performed using paraffin-embedded tissues (PRA-H n = 53, PRB-H n = 24), and protein expression analyzed by immunohistochemistry. All statistical tests were two-sided.

Results

One hundred sixteen out of 222 (52.3%) PR+ tumors were PRA-H, and 64 (28.8%) PRB-H. Cell proliferation was inhibited by MFP in 19 of 19 tissue cultures from PRA-H tumors. A total of 139 transcripts related to proliferative pathways were differentially expressed in nine PRA-H and seven PRB-H tumors. PRB-H and PRA-H tumors were either luminal B or A phenotypes, respectively ( P = .03). PRB-H cases were associated with shorter relapse-free survival (hazard ratio [HR] = 2.70, 95% confidence interval [CI] = 1.71 to 6.20, P = .02) and distant metastasis-free survival (HR = 4.17, 95% CI = 2.18 to 7.97, P <  .001). PRB-H tumors showed increased tumor size ( P <  .001), Ki-67 levels ( P <  .001), human epidermal growth factor receptor 2 expression ( P =  .04), high grades ( P =  .03), and decreased total PR ( P =  .004) compared with PRA-H tumors. MUC-2 ( P <  .001) and KRT6A ( P =  .02) were also overexpressed in PRB-H tumors.

Conclusion

The PRA/PRB ratio is a prognostic and predictive factor for antiprogestin responsiveness in breast cancer.

Khan F, Schmitz U, Wolkenhauer O, Gupta SK. MicroRNA and Transcription Factor Gene Regulatory Network Analysis Reveals Key Regulatory Elements Associated with Prostate Cancer Progression

Technological and methodological advances in multi-omics data generation and integration approaches help elucidate genetic features of complex biological traits and diseases such as prostate cancer. Due to its heterogeneity, the identification of key functional components involved in the regulation and progression of prostate cancer is a methodological challenge. In this study, we identified key regulatory interactions responsible for primary to metastasis transitions in prostate cancer using network inference approaches by integrating patient derived transcriptomic and miRomics data into gene/miRNA/transcription factor regulatory networks. One such network was derived for each of the clinical states of prostate cancer based on differentially expressed and significantly correlated gene, miRNA and TF pairs from the patient data. We identified key elements of each network using a network analysis approach and validated our results using patient survival analysis. We observed that HOXD10, BCL2 and PGR are the most important factors affected in primary prostate samples, whereas, in the metastatic state, STAT3, JUN and JUNB are playing a central role. Benefiting integrative networks our analysis suggests that some of these molecules were targeted by several overexpressed miRNAs which may have a major effect on the dysregulation of these molecules. For example, in the metastatic tumors five miRNAs (miR-671-5p, miR-665, miR-663, miR-512-3p and miR-371-5p) are mainly responsible for the dysregulation of STAT3 and hence can provide an opportunity for early detection of metastasis and development of alternative therapeutic approaches. Our findings deliver new details on key functional components in prostate cancer progression and provide opportunities for the development of alternative therapeutic approaches.

Progesterone receptor antagonism inhibits progestogen-related carcinogenesis and suppresses tumor cell proliferation

PURPOSE

Blockade of the progestogen-progesterone receptor (PR) axis is a novel but untested strategy for breast cancer prevention. We report preclinical data evaluating telapristone acetate (TPA), ulipristal acetate (UPA), and mifepristone.

METHODS

Tumors were induced with medroxyprogesterone acetate (MPA) plus 7,12-dimethylbenz[a]anthracene (DMBA) in mice, and MPA or progesterone plus N-methyl-N-nitrosourea (MNU) in rats. Mammary gland histology, tumor incidence, latency, multiplicity, burden and histology were evaluated, along with immunohistochemical labeling of pHH3 (proliferation), CD34 (angiogenesis), and estrogen and progesterone receptors (ER and PR). A concentration gradient of TPA, UPA, and mifepristone was tested for growth inhibition of T47D spheroids.

RESULTS

In mouse mammary glands, no tumors formed, but TPA opposed the pro-hyperplastic effects of MPA (p = 0.002). In rats, TPA decreased tumor incidence (p = 0.037 for MPA + TPA vs. MPA, and p = 0.032 for progesterone + TPA vs. progesterone) and tumor burden (p = 0.042 for progesterone + TPA vs. progesterone), with significant decreases in pHH3 and CD34 positive cells. TPA and UPA were superior to mifepristone in growth inhibition of T47D spheroids.

CONCLUSION

TPA has consistent anti-tumorigenic effects in several models, which are accompanied by decreases in cell proliferation, angiogenesis, and hormone receptor expression.