Prolactin Receptor Levels Research Articles

Wheel Running During Pregnancy Alleviates Anxiety-and Depression-Like Behaviors During the Postpartum Period in Mice: The Roles of NLRP3 Neuroinflammasome Activation, Prolactin, and the Prolactin Receptor in the Hippocampus.

Despite the increase in the prevalence of postpartum depression among maternal disorder, its treatment outcomes remain suboptimal. Studies have shown that exercise can reduce postpartum depressive episodes in the mother, but the effects of exercise during pregnancy on maternal behavior and the potential mechanisms involved remain poorly understood. From the second day of pregnancy to the day of birth, dams exercised for 1h a day by running on a controlled wheel. The maternal behaviors of the dams were assessed on postpartum day 2 to postpartum day 8. Chronic restraint stress was applied from postpartum day 2 to day 12. Blood was collected on postpartum days 3 and 8, then subjected to ELISA to determine the serum concentration of prolactin. The weight of each dam and the food intake were recorded. Anxiety- and depression-like behavioral tests were conducted, and hippocampal neuroinflammation and prolactin receptor levels were measured. The dams exhibited elevated levels of anxiety and depression, decreased serum prolactin levels, decreased prolactin receptor expression, and activation of NLRP3-mediated neuroinflammation in the hippocampus following the induction of postpartum chronic restraint stress, which were reversed with controlled wheel running during pregnancy. Overall, the findings of this study revealed that the preventive effects of exercise during pregnancy on postpartum anxiety-and depression-like behaviors were accompanied by increased serum prolactin levels, hippocampal prolactin receptor expression and hippocampal NLRP3-mediated neuroinflammation.

The immunotoxin targeting PRLR increases tamoxifen sensitivity and enhances the efficacy of chemotherapy in breast cancer

BackgroundThough tamoxifen achieves success in treating estrogen receptor α (ERα)-positive breast cancer, the followed development of tamoxifen resistance is a common challenge in clinic. Signals downstream of prolactin receptor (PRLR) could synergize with ERα in breast cancer progression. However, the potential effect of targeting PRL-PRLR axis combined with tamoxifen has not been thoroughly investigated.MethodsHigh-throughput RNA-seq data obtained from TCGA, Metabric and GEO datasets were analyzed to explore PRLR expression in breast cancer cell and the association of PRLR expression with tamoxifen treatment. Exogenous or PRL overexpression cell models were employed to investigate the role of activated PRLR pathway in mediating tamoxifen insensitivity. Immunotoxin targeting PRLR (N8-PE24) was constructed with splicing-intein technique, and the efficacy of N8-PE24 against breast cancer was evaluated using in vitro and in vivo methods, including analysis of cells growth or apoptosis, 3D spheroids culture, and animal xenografts.ResultsPRLR pathway activated by PRL could significantly decrease sensitivity of ERα-positive breast cancer cells to tamoxifen. Tamoxifen treatment upregulated transcription of PRLR and could induce significant accumulation of PRLR protein in breast cancer cells by alkalizing lysosomes. Meanwhile, tamoxifen-resistant MCF7 achieved by long-term tamoxifen pressure exhibited both upregulated transcription and protein level of PRLR. Immunotoxin N8-PE24 enhanced sensitivity of breast cancer cells to tamoxifen both in vitro and in vivo. In xenograft models, N8-PE24 significantly enhanced the efficacy of tamoxifen and paclitaxel when treating PRLR-positive triple-negative breast cancer.ConclusionsPRL-PRLR axis potentially associates with tamoxifen insensitivity in ERα-positive breast cancer cells. N8-PE24 could inhibit cell growth of the breast cancers and promote drug sensitivity of PRLR-positive breast cancer cells to tamoxifen and paclitaxel. Our study provides a new perspective for targeting PRLR to treat breast cancer.

Effects of prolactin on the proliferation and hormone secretion of ovine granulosa cells in vitro.

The objective of this study was to investigate the effects of prolactin (PRL) on the proliferation and apoptosis of ovine ovarian granulosa cells (GCs) and the secretion of estrogen (E2) and progesterone (P4), as well as to explore the effects of PRL on related genes and proteins. We isolated ovarian GCs from 1-year-old small-tail Han sheep and identified PRL receptor (PRLR) on ovaries and follicle stimulating hormone receptor (FSHR) on ovarian GCs, respectively, using immunohistochemistry. PRL (0, 0.05, 0.50, 5.00 μg/mL) were added to GCs in vitro along with FSH, cell proliferation was measured by cell counting Kit-8 (CCK-8) and apoptosis by flow cytometry. The measurement of E2 and P4 content by enzyme-linked immunosorbent assays after 48 h and 72 h. The expression of functional genes and proteins was identified by real-time quantitative polymerase chain reaction (RTqPCR) and Western-blot after 48 h. PRLR was expressed in both follicular GCs and corpus luteum, whereas FSHR was expressed specifically. The proliferative activity was lower on day 1 while higher on day 4 and day 5. The apoptosis rate of GCs in the 0.05 μg/mL group was significantly higher than that in the control group after treatment with PRL for 24 h (p<0.05). Compared with the control group, the secretion of E2 in GCs was reduced significantly (p<0.05) in PRL treatment for 48 h and 72 h, while the secretion of P4 was significantly increased (p<0.05). The mRNA expression levels of PRLR, FSHR, LHR, CYP11A1, HSD3B7, and STAR were significantly higher than those in the control group (p<0.01), and the relative abundance of BCL2 in all PRL group were increased after PRL treatment. PRL promoted the proliferation of GCs and supraphysiological concentrations inhibited apoptosis caused by down-regulation of BAX and up-regulation of BCL2. PRL inhibited E2 by down-regulating CYP19A1 and promoted P4 by up-regulating CYP11A1, STAR, and HSD3B7.

Sacubitril/Valsartan Alleviates Cardiac Remodeling and Dysfunction in L-NAME-Induced Hypertension and Hypertensive Heart Disease.

There is ample evidence on the benefit of angiotensin receptor-neprilysin inhibitors (ARNIs) in heart failure, yet data regarding the potential protective action of ARNIs in hypertensive heart disease are sparse. The aim of this study was to show whether an ARNI exerts a protective effect in a model of Nω-nitro-L-arginine methyl ester (L-NAME)-induced hypertension with a hypertensive heart and to compare this potential benefit with an angiotensin-converting enzyme inhibitor, captopril. Five groups of adult male Wistar rats were studied (14 per group) for four weeks: untreated controls; ARNI (68 mg/kg/day); L-NAME (40 mg/kg/day); L-NAME treated with ARNI; and L-NAME treated with captopril (100 mg/kg/day). L-NAME administration induced hypertension, accompanied by increased left ventricular (LV) weight and fibrotic rebuilding of the LV in terms of increased concentration and content of hydroxyproline in insoluble collagen and in total collagen and with a histological finding of fibrosis. These alterations were associated with a compromised systolic and diastolic LV function. Treatment with either an ARNI or captopril reduced systolic blood pressure (SBP), alleviated LV hypertrophy and fibrosis, and prevented the development of both systolic and diastolic LV dysfunction. Moreover, the serum levels of prolactin and prolactin receptor were reduced significantly by ARNI and slightly by captopril. In conclusion, in L-NAME-induced hypertension, the dual inhibition of neprilysin and AT1 receptors by ARNI reduced SBP and prevented the development of LV hypertrophy, fibrosis, and systolic and diastolic dysfunction. These data suggest that ARNI could provide protection against LV structural remodeling and functional disorders in hypertensive heart disease.

Impaired microRNA-21 and prolactin receptor levels in the decidua of the prepubertal offspring of diabetic rats are prevented by maternal diets enriched in olive oil

Impaired microRNA-21 and prolactin receptor levels in the decidua of the prepubertal offspring of diabetic rats are prevented by maternal diets enriched in olive oil

Jiawei Shoutai Pill promotes decidualization by regulating the SGK1/ENaC pathway in recurrent spontaneous abortion

Ethnopharmacological relevanceJiawei Shoutai Pill (JWSTW) is a traditional herbal formula for recurrent spontaneous abortion (RSA). Although JWSTW significantly improves the clinical symptoms of RSA patients, its molecular mechanism remains unclear. Aim of studyThis study evaluated the expression and function of the serum/glucocorticoid regulated kinase 1/epithelial sodium channel (SGK1/ENaC) pathway and decidualization level in RSA patients and mice. It also investigated the therapeutic effects and potential mechanisms of JWSTW. Materials and methods30 early RSA patients and 30 normal pregnant women undergoing induced abortion during the same period were included in the study. Decidual tissues were collected, and HE staining, immunohistochemistry, Western blot, and RT-PCR were used to detect protein and mRNA expression levels of SGK1, ENaC-a, estrogen Rreceptor β (ERβ), and progesterone receptor (PR) in patients’ decidual tissues. Protein expression levels of prolactin receptor (PRLR) and insulin-like growth factor binding protein 1 (IGFBP-1) were also detected. A classical RSA mouse model was constructed, and the mice were randomly divided into four groups: normal, model, dydrogesterone (DQYT) (0.33 g/kg/d), and JWSTW (1.66 g/kg/d). The normal and model groups received the same volume of distilled water by gavage for 8 and 14 days after pregnancy. On the 14th day of pregnancy, the embryonic loss rate of each group, the number of offspring born to naturally delivered mice, and the protein or mRNA expression levels of key factors of the SGK1/ENaC pathway (SGK1, ENaC-a, ERβ, and PR), decidual proliferation marker (Ki67), mesenchymal-epithelial transition (E-cadherin and Vimentin), and decidualization markers (PRLR and IGFBP-1) in mouse decidual tissue on the eighth day of pregnancy were observed. ResultsThe decidual tissue structure of RSA patients was abnormal. Immunohistochemical analysis revealed significantly reduced positive expression of SGK1, ENaC-a, ERβ, and PR proteins in the decidual tissue of RSA patients (P < 0.001). Western blot and RT-PCR analyses demonstrated significantly decreased protein and mRNA expression of SGK1, ENaC-a, ERβ, and PR in the decidual tissue of RSA patients (all P < 0.05). Additionally, protein expression of PRLR and IGFBP-1 was significantly reduced (both P < 0.001). The RSA mouse model exhibited a significant increase in embryo loss rate and decreased litter size (both P < 0.001). Treatment with DQYT and JWSTW rescued the embryo loss rate and litter size to varying extents (all P < 0.05). The protein or mRNA expression levels of SGK1, ENaC-a, ERβ, PR, Ki67, E-cadherin, vimentin, PRLR, and IGFBP-1 in RSA mice were improved to different degrees after treatment with DQYT and JWSTW (all P < 0.05). ConclusionsAbnormal SGK1/ENaC signaling pathway regulation is closely associated with early endometrial damage in RSA patients. JWSTW promotes endometrial proliferation and mesenchymal-epithelial transition through the SGK1/ENaC signaling pathway, improving endometrial shedding. Consequently, JWSTW is a potential treatment for RSA.

Prolactin receptor signaling induces acquisition of chemoresistance and reduces clonogenicity in acute myeloid leukemia

BackgroundDevelopment of precision medicine requires the identification of easily detectable and druggable biomarkers. Despite recent targeted drug approvals, prognosis of acute myeloid leukemia (AML) patients needs to be greatly improved, as relapse and refractory disease are still difficult to manage. Thus, new therapeutic approaches are needed. Based on in silico-generated preliminary data and the literature, the role of the prolactin (PRL)-mediated signaling was interrogated in AML.MethodsProtein expression and cell viability were determined by flow cytometry. Repopulation capacity was studied in murine xenotransplantation assays. Gene expression was measured by qPCR and luciferase-reporters. SA-β-Gal staining was used as a senescence marker.ResultsThe prolactin receptor (PRLR) was upregulated in AML cells, as compared to their healthy counterpart. The genetic and molecular inhibition of this receptor reduced the colony-forming potential. Disruption of the PRLR signaling, either using a mutant PRL or a dominant-negative isoform of PRLR, reduced the leukemia burden in vivo, in xenotransplantation assays. The expression levels of PRLR directly correlated with resistance to cytarabine. Indeed, acquired cytarabine resistance was accompanied with the induction of PRLR surface expression. The signaling associated to PRLR in AML was mainly mediated by Stat5, in contrast to the residual function of Stat3. In concordance, Stat5 mRNA was significantly overexpressed at mRNA levels in relapse AML samples. A senescence-like phenotype, measured by SA-β-gal staining, was induced upon enforced expression of PRLR in AML cells, partially dependent on ATR. Similar to the previously described chemoresistance-induced senescence in AML, no cell cycle arrest was observed. Additionally, the therapeutic potential of PRLR in AML was genetically validated.ConclusionsThese results support the role of PRLR as a therapeutic target for AML and the further development of drug discovery programs searching for specific PRLR inhibitors.

Medicinal Mushroom Leucocalocybe mongolica Imai Extracts Improve Mammary Gland Differentiation in Lactating Rats via Regulating Protein Expression.

Leucocalocybe mongolica is a known medicinal mushroom in China. It possesses many biological activities. This study investigated the effect of L. mongolica petroleum ether and water extracts (200, 500, and 1,000 mg/kg BW) on mammary gland differentiation during lactation. However, prolactin, growth hormone, progesterone, and estrogen levels were determined in serum by ELISA assay. Immunofluorescence, western blot, and real-time PCR were utilized to evaluate the expression levels of β-casein, α-Lactalbumin, prolactin receptor, progesterone receptor, and STAT-5a. The immunohistochemistry staining was used to detect the presence of steroid receptors. The results showed that petroleum ether and water extracts increased milk yield and milk content of calcium, total fat, total carbohydrate, and total protein. Prolactin and growth hormone levels were significantly upregulated in all treated groups compared with the control group. In contrast, progesterone and estrogen were downregulated. The high doses of petroleum ether and water extracts increased the expression levels of β-Cas, α-Lactalb, PRLR, PR, and STAT-5a. The observation of histological sections showed that the extracts induced higher mammary gland differentiation than the control group. This study is the first to use mushrooms as nutritional supplements to improve milk production and mammary gland differentiation during lactation.

The Circ-CYP24A1-miR-224-PRLR Axis Impairs Cell Proliferation and Apoptosis in Recurrent Miscarriage.

AimRecurrent miscarriage (RM) is associated with numerous clinical factors. However, some RM occurred without specific factors. It has been revealed that some molecules such as hormones, miRNAs, and transcription factors are involved in RM by regulating proliferation, apoptosis, etc. However, the mechanism of RM has yet to be identified clearly. Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that often act as sponges for miRNAs or binds to proteins involved in biological processes. However, the functional role of circRNAs in the uterine decidua of patients with early RM is still unclear. In this study, we aimed to investigate the mechanisms of circ-CYP24A1 in RM.MethodsThe Dual-Luciferase Activity Assay was designed to analyze the bonding between circ-CYP24A1 and miR-224, and miR-224 and prolactin receptor (PRLR) mRNA 3′UTR. In situ hybridization (ISH) and immunohistochemistry (IHC) were used to observe the expression of circ-CYP24A1 and PRLR in the decidua. Rescue experiments were performed to investigate the regulating effects of circ-CYP24A1, miR-224, and PRLR. Western blotting was conducted to test the expression level of PRLR. The proliferation and apoptosis-related markers in Ishikawa cells were analyzed using CCK8, immunofluorescence staining, and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay.ResultsIn this study, based on the microarray analysis data, we identified a high level of circ-CYP24A1 and PRLR in the decidua of patients with early RM. Based on the bioinformatics prediction, the binding relationship between circ-CYP24A1 and miR-224, as well as miR-224 and PRLR, were verified. Functional experiments demonstrated that circ-CYP24A1 regulated proliferation and apoptosis by binding to and inhibiting miR-224, resulting in increased PRLR expression. Taken together, this study provides new insights into the mechanism of RM.ConclusionIn this study, we found that circ-CYP24A1 plays a role in RM by impairing the balance of cell proliferation and apoptosis by sponging miR-224, thereby regulating PRLR.

Crosstalk between PRLR and EGFR/HER2 Signaling Pathways in Breast Cancer.

Simple SummaryProlactin receptor (PRLR) and epidermal growth factor receptor (EGFR/ERBB) signaling pathways have a crucial role in the development of mammary glands and breast carcinogenesis. In this review, we have provided ample evidence to support the significant role for PRLR and EGFR/HER2 signaling crosstalk in breast cancer. Recent studies from our lab and other finding also recognize how these two receptors work together to induce hyperactivation of their downstream signaling kinases that overlap with each other and in turn further induce target genes and other pro-oncogenic factors. Prolactin through PRLR can activate both EGFR and HER2 downstream signaling pathways which in turn leads to activation of other oncogenic growth factors that promote growth, survival, and proliferation of breast cancer cells. The crosstalk between PRLR and EGFR/HER2 signaling is an additional route that magnifies the actions of their ligands, and further promote tumor growth. This may be responsible for endocrine resistance in breast cancer patients resulting in tumor relapse.Prolactin receptor (PRLR) and epidermal growth factor receptor (EGFR/ERBB) signaling pathways activated by prolactin (PRL) and epidermal growth factor (EGF), have a major role in the mammary gland development and in the etiology of breast cancer, respectively. ER+ breast tumors comprise up to 75% of all breast cancers and 10% of these are HER2+. Elevated levels of PRLR in breast tumors, high circulating levels of PRL and increased expression of ERBB1/2 in patients that become resistant to endocrine therapy have shown to be associated with higher risk of cancer progression. In this review, we examine the role of crosstalk between PRLR and ERBB1/2 signaling pathways in the activation of unliganded ERα, cyclin-D1 and other oncogenic factors (MYC, FOS, JUN) in breast cancer. PRL/PRLR and EGF/EGFR induces phosphorylation of ERα through activation of MEK/MAPK and PI3K/AKT signaling pathways. PRL in breast cancer cells via PRLR/JAK2 can also induce phosphorylation of ERBB2/HER2, which in turn activates the downstream RAS/MEK/ERK pathway required for ERα phosphorylation. EGFR, independent of PRL/PRLR, can activate STAT5 indirectly via c-SRC and drive the expression of target genes involved in cell proliferation and survival. The crosstalk between PRLR and HER2, where PRL induces HER2 signaling can be an alternative route for ERα activation to induce transcription of PRLR and other ER target genes. We believe that overexpression of EGFR/HER2 and PRLR in breast tumors could maximize the actions of their ligands, and further induce cell proliferation promoting malignancy. This could also explain the resistance to endocrine therapy resulting in tumor growth.

Prolactin receptor regulates the seasonal reproduction of striped hamsters

In this study, differential mRNA expression patterns of prolactin receptor (PRLR) in the hypothalamus and gonads, and the correlation with follicle stimulating hormone (FSH) and luteinizing hormone (LH) in striped hamster serum from spring, summer, autumn and winter were analyzed. Mature female and male striped hamsters in oestrus were used. Expression levels of PRLR in the hypothalamus, ovaries and testis from the summer and winter individuals were significantly higher compared with levels from the spring and autumn, whereas FSH and LH serum concentrations from summer and winter individuals were significantly lower compared with that from the spring and autumn. PRLR expression levels in hypothalamus, ovaries and testis were negatively correlated with FSH and LH serum concentrations, illustrating that PRLR might negatively regulate seasonal reproductive activity. PRLR expression levels in ovaries and testes were significantly higher compared with levels in the hypothalamus, suggesting that the regulative effects of PRLR in gonads might be significantly higher compared with that in the hypothalamus. Furthermore, PRLR expression levels from the spring, summer, autumn and winter seasons in the hypothalamus and gonads were significantly higher in females compared with levels in males, indicating that the regulative effect of PRLR might be sex dependent. Taken together, this study helps to understand in depth the seasonal regulative reproduction mechanism of striped hamsters to reasonably control population abundance.

Prolactin and vitiligo: proposed autocrine/paracrine actions

Background The exact cause of vitiligo remains unclear. Several theories have been proposed, including autoimmune and neuroendocrine theories. Prolactin has been studied as an immunomodulatory factor in several autoimmune diseases. Regarding vitiligo, previous studies revealed contradictory results. This is the first study to assess tissue prolactin and prolactin receptor (PRLR) expression in vitiligo. Objective To measure the level of serum prolactin, tissue prolactin, as well as PRLR in patients with vitiligo vulgaris and controls to verify their possible role in vitiligo pathogenesis. Patients and methods A case–control study was conducted on 40 participants: 20 patients with vitiligo and 20 age-matched and sex-matched healthy controls. Blood samples were taken to determine the serum prolactin level (ng/ml). Skin biopsies were obtained from the lesional skin of patients and normal skin of controls to determine the level of tissue prolactin (ng/mg) and PRLR (ng/g) by enzyme-linked immunosorbent assay. Results Serum and tissue prolactin and PRLR levels were significantly higher in patients than in controls (P<0.001). Tissue prolactin level had a positive correlation with PRLR level (r=0.739, P<0.001). Conclusion Prolactin plays a role in the pathogenesis of vitiligo, mainly from an intracutaneous position where an autocrine/paracrine loop could have a larger share.

Sexually dimorphic effects of prolactin treatment on the onset of puberty and olfactory function in mice

The onset of puberty is associated with the psychophysiological maturation of the adolescent to an adult capable of reproduction when olfactory signals play an important role. This period begins with the secretion of the gonadotropin-releasing hormone (GnRH) from GnRH neurons within the hypothalamus. This is regulated by kisspeptin neurons that express high levels of transmembrane prolactin receptors (PRLR) that bind to and are activated by prolactin (PRL). The elevated levels of serum PRL found during lactation, or caused by chronic PRL infusion, decreases the secretion of gonadotropins and kisspeptin and compromised the estrous cyclicity and the ovulation. In the present work, we aimed to evaluate the effects of either increased or decreased PRL circulating levels within the peripubertal murine brain by administration of PRL or treatment with cabergoline (Cab) respectively. We showed that either treatment delayed the onset of puberty in females, but not in males. This was associated with the augmentation of the PRL receptor (Prlr) mRNA expression in the arcuate nucleus and decreased Kiss1 expression in the anteroventral periventricular zone. Then, during adulthood, we assessed the activation of the mitral and granular cells of the main (MOB) and accessory olfactory bulb (AOB) by cFos immunoreactivity (ir) after the exposure to soiled bedding of the opposite sex. In the MOB, the PRL treatment promoted an increased cFos-ir of the mitral cells of males and females. In the granular cells of male of either treatment an augmented activation was observed. In the AOB, an impaired cFos-ir was observed in PRL and Cab treated females after exposure to male soiled bedding. However, in males, only Cab impaired its activation. No effects were observed in the AOB-mitral cells. In conclusion, our results demonstrate that PRL contributes to pubertal development and maturation of the MOB-AOB during the murine juvenile period in a sex-dependent way.

Bisphenol A and benzophenone-3 exposure alters milk protein expression and its transcriptional regulation during functional differentiation of the mammary gland in vitro

The plastic monomer and plasticizer bisphenol A (BPA), and the UV-filter benzophenone-3 (BP3) have been shown to have estrogenic activities that could alter mammary gland development. Our aim was to analyze whether BPA or BP3 direct exposure affects the functional differentiation of the mammary gland using an in vitro model. Mammary organoids were obtained and isolated from 8 week-old virgin female C57BL/6 mice and were differentiated on Matrigel with medium containing lactogenic hormones and exposed to: a) vehicle (0.01% ethanol); b) 1 × 10−9 M or 1 × 10−6 M BPA; or c) 1 × 10−12 M, 1 × 10−9 M or 1 × 10−6 M BP3 for 72 h. The mRNA and protein expression of estrogen receptor alpha (ESR1) and progesterone receptor (PR) were assessed. In addition, mRNA levels of PR-B isoform, glucocorticoid receptor (GR), prolactin receptor (PRLR) and Stat5a, and protein expression of pStat5a/b were evaluated at 72 h. The mRNA and protein expression of milk proteins and their DNA methylation status were also analyzed. Although mRNA level of PRLR and GR was similar between treatments, mRNA expression of ESR1, total PR, PR-B and Stat5a was increased in organoids exposed to 1 × 10−9 M BPA and 1 × 10−12 M BP3. Total PR expression was also increased with 1 × 10−6 M BPA. Nuclear ESR1 and PR expression was observed in all treated organoids; whereas nuclear pStat5a/b alveolar cells was observed only in organoids exposed to 1 × 10−9 M BPA and 1 × 10−12 M BP3. The beta-casein mRNA level was increased in both BPA concentrations and 1 × 10−12 M BP3, which was associated with hypomethylation of its promoter. The beta-casein protein expression was only increased with 1 × 10−9 M BPA or 1 × 10−12 M BP3. In contrast, BPA exposure decreased alpha-lactalbumin mRNA expression and increased DNA methylation level in different methylation-sensitive sites of the gene. Also, 1 × 10−9 M BPA decreased alpha-lactalbumin protein expression. Our results demonstrate that BPA or BP3 exposure alters milk protein synthesis and its transcriptional regulation during mammary gland differentiation in vitro.

Epigenetic modifications in the GH-dependent Prlr, Hnf6, Cyp7b1, Adh1 and Cyp2a4 genes.

Many sex differences in liver gene expression originate in the brain, depend on GH secretion and may underlie sex disparities in hepatic disease. Because epigenetic mechanisms may contribute, we studied promoter methylation and microRNA abundance in the liver, associated with expression of sexual dimorphic genes in mice with selective disruption of the dopamine D2 receptor in neurons (neuroDrd2KO), which decreases hypothalamic Ghrh, pituitary GH, and serum IGFI and in neonatally androgenized female mice which have increased pituitary GH content and serum IGFI. We evaluated mRNA levels of the female predominant genes prolactin receptor (Prlr), alcohol dehydrogenase 1 (Adh1), Cyp2a4, and hepatocyte nuclear transcription factor 6 (Hnf6) and the male predominant gene, Cyp7b1. Female predominant genes had higher mRNA levels compared to males, but lower methylation was only detected in the Prlr and Cyp2a4 female promoters. In neuroDrd2KO mice, sexual dimorphism was lost for all genes; the upregulation (feminization) of Prlr and Cyp2a4 in males correlated with decreased methylation of their promoters, and the downregulation (masculinization) of Hnf-6 mRNA in females correlated inversely with its promoter methylation. Neonatal androgenization of females evoked a loss of sexual dimorphism only for the female predominant Hnf6 and Adh1 genes, but no differences in promoter methylation were found. Finally, mmu-miR-155-5p, predicted to target Cyp7b1 expression, was lower in males in association with higher Cyp7b1 mRNA levels compared to females and was not modified in neuroDrd2KO or TP mice. Our results suggest specific regulation of gene sexually dimorphic expression in the liver by methylation or miRNAs.

Inter-individual variability in freshwater tolerance is related to transcript level differences in gill and posterior kidney of European sea bass.

Acclimation to low salinities is a vital physiological challenge for euryhaline fish as the European sea bass Dicentrarchus labrax. This species undertakes seasonal migrations towards lagoons and estuaries where a wide range of salinity variations occur along the year. We have previously reported intraspecific differences in freshwater tolerance, with an average 30% mortality rate. In this study, we bring new evidence of mechanisms underlying freshwater tolerance in sea bass at gill and kidney levels. In fresh water (FW), intraspecific differences in mRNA expression levels of several ion transporters and prolactin receptors were measured. We showed that the branchial Cl-/HCO3- anion transporter (slc26a6c) was over-expressed in freshwater intolerant fish, probably as a compensatory response to low blood chloride levels and potential metabolic alkalosis. Moreover, prolactin receptor a (prlra) and Na+/Cl- cotransporter (ncc1) but not ncc-2a expression seemed to be slightly increased and highly variable between individuals in freshwater intolerant fish. In the posterior kidney, freshwater intolerant fish exhibited differential expression levels of slc26 anion transporters and Na+/K+/2Cl- cotransporter 1b (nkcc1b). Lower expression levels of prolactin receptors (prlra, prlrb) were measured in posterior kidney which probably contributes to the failure in ion reuptake at the kidney level. Freshwater intolerance seems to be a consequence of renal failure of ion reabsorption, which is not sufficiently compensated at the branchial level.

Analysis of prolactin receptor expression in breast cancer subtypes

Breast cancer (BC) is the most common cancer among women. It is known that the prolactin receptor (PRLR) may play a role in breast carcinogenesis, but the available data are often contradictory. To get a more complete picture of the relationship between the receptor and mammary gland carcinogenesis, we examined the association between changes in PRLR expression level and tumor subtype (and its main characteristics). To do this, using real-time PCR, we evaluated the level of PRLR mRNA in BC tissue samples and untransformed adjoining tissue samples (89 pairs). Since the androgen receptor (AR) has begun to be seen as a prognostic marker in breast cancer, we also evaluated the association between mRNA levels of AR and PRLR. We found a significant increase in PRLR expression in luminal subtypes; the highest level of PRLR mRNA was detected in luminal A subtype. In HER2-positive ER-, PR-negative BC, the PRLR mRNA level decreases in tumor tissues compared with untransformed tissues. High PRLR expression is also associated with smaller tumor size in luminal B HER2-negative subtype. In ER-, PR-negative tumors, PRLR expression is associated with AR expression: PRLR mRNA level is increased when AR mRNA level is reduced by more than 8 times in triple-negative tumors; in contrast, in HER2-positive subtype it decreases more significantly when AR expression is reduced by more than 3 times. A tendency towards an increase in PRLR expression with an increase in the AR mRNA level was also discovered in luminal subtypes. The level of PRLR expression depends on the age of patients. In luminal A, PRLR expression is higher in patients under 65 years. In contrast, in luminal B HER2-negative and triple-negative BC, reduced PRLR expression was observed in patients under the age of 40 years and under the age of 50 years, respectively. In this group of patients under the age of 40 years with luminal B HER2-negative BC, ER expression was also reduced (0-4 score according to the IHC assay). Thus, PRLR probably plays a different role in the development and progression of BC: in luminal A and luminal B HER2-positive subtypes PRLR may act as an oncogen, and in luminal B HER2-negative and ER-, PR-negative subtypes can play a tumor suppressor role.

Diphenylbutylpiperidine Antipsychotic Drugs Inhibit Prolactin Receptor Signaling to Reduce Growth of Pancreatic Ductal Adenocarcinoma in Mice

Prolactin (PRL) signaling is up-regulated in hormone-responsive cancers. The PRL receptor (PRLR) is a class I cytokine receptor that signals via the Janus kinase (JAK)-signal transducer and activator of transcription and mitogen-activated protein kinase pathways to regulate cell proliferation, migration, stem cell features, and apoptosis. Patients with pancreatic ductal adenocarcinoma (PDAC) have high plasma levels of PRL. We investigated whether PRLR signaling contributes to the growth of pancreatic tumors in mice. We used immunohistochemical analyses to compare levels of PRL and PRLR in multitumor tissue microarrays. We used structure-based virtual screening and fragment-based drug discovery to identify compounds likely to bind PRLR and interfere with its signaling. Human pancreatic cell lines (AsPC-1, BxPC-3, Panc-1, and MiaPaCa-2), with or without knockdown of PRLR (clustered regularly interspaced short palindromic repeats or small hairpin RNA), were incubated with PRL or penfluridol and analyzed in proliferation and spheroid formation. C57BL/6 mice were given injections of UNKC-6141 cells, with or without knockdown of PRLR, into pancreas, and tumor development was monitored for 4 weeks, with some mice receiving penfluridol treatment for 21 days. Human pancreatic tumor tissues were implanted into interscapular fat pads of NSG mice, and mice were given injections of penfluridol daily for 28 days. Nude mice were given injections of Panc-1 cells, xenograft tumors were grown for 2 weeks, and mice were then given intraperitoneal penfluridol for 35 days. Tumors were collected from mice and analyzed by histology, immunohistochemistry, and immunoblots. Levels of PRLR were increased in PDAC compared with nontumor pancreatic tissues. Incubation of pancreatic cell lines with PRL activated signaling via JAK2-signal transducer and activator of transcription 3 and extracellular signal-regulated kinase, as well as formation of pancospheres and cell migration; these activities were not observed in cells with PRLR knockdown. Pancreatic cancer cells with PRLR knockdown formed significantly smaller tumors in mice. We identified several diphenylbutylpiperidine-class antipsychotic drugs as agents that decreased PRL-induced JAK2 signaling; incubation of pancreatic cancer cells with these compounds reduced their proliferation and formation of panco spheres. Injections of 1 of these compounds, penfluridol, slowed the growth of xenograft tumors in the different mouse models, reducing proliferation and inducing autophagy of the tumor cells. Levels of PRLR are increased in PDAC, and exposure to PRL increases proliferation and migration of pancreatic cancer cells. Antipsychotic drugs, such as penfluridol, block PRL signaling in pancreatic cancer cells to reduce their proliferation, induce autophagy, and slow the growth of xenograft tumors in mice. These drugs might be tested in patients with PDAC.

Pregnancy-induced changes in the transcript levels of prolactin receptor and its suppressor in the ovine hypothalamus and adenohypophysis.

The aim of this study was to analyse changes in the abundance of prolactin (PRL) receptor (PRLR) and suppressor of cytokine signalling-3 (SOCS-3) mRNA in the ventro-/dorsomedial nucleus (VMH/DMH) and arcuate nucleus (ARC) of the hypothalamus as well as in the median eminence (ME) and adenohypophysis (AP) in sheep at 30, 60, 90 and 120 d of pregnancy compared to non-pregnant animals. In the VMH/DMH, PRLR transcripts were detected only in non-pregnant ewes. In the ARC, the abundances of PRLR mRNA were higher in pregnant sheep on days 30 (p<.01), 90 (p<.01) and 120 (p<.05) than in non-pregnant sheep. In contrast, the expression of PRLR mRNA in the ME was lower (p<.01) in pregnant ewes at days 30 and 60 than in non-pregnant ewes and was undetectable at later stages of gestation. In all studied stages of pregnancy except day 60, the abundance of PRLR mRNA was higher (p<.01) in the ARC than in the AP, while in non-pregnant sheep, there were no differences (p≥.05) in the transcript levels between these two tissues. In non-pregnant ewes, the abundance of SOCS-3 mRNA in the AP was lower than that in any other studied tissue (p<.05-p<.01). In conclusion, the observed changes in PRLR and SOCS-3 mRNA abundance in the hypothalamus and AP during pregnancy may be important components of the mechanisms regulating the action of PRL in energy homeostasis and neuroendocrine interactions within the hypothalamic-pituitary axis.

MON-LB054 Activity of Prolactin Receptor Antagonist-Rapamycin Conjugate in Glioblastoma Multiform

Background: Glioblastoma multiform (GBM) is the most common and aggressive primary brain tumor in humans, accounting for approximately 12-15% of all intracranial tumors, with a median survival of 15 months. Although GBM is not considered a hormone sensitive cancer but recent studies showed significant increased levels of prolactin receptors (PRLR) in response to combined application of angiogenic inhibitors on GBM in vivo. Tuberous Sclerosis complex (TSC) proteins suppress the mTOR pathway and the discovery that certain tumors have lost TSC functionality immediately suggested how to treat the over-activity of mTOR in some cancers. Patients with TSC have bi-allelic loss of TSC1/TSC2, and a few clinical cases have been reported the occurrence of GBM in such patients and experimental studies reported increased STAT and mTOR activity in GBM. Hypothesis: Compounds blocking the PRLR have not yet reached the clinic and rapamycin is a clinical drug blocking mTOR, which serves to slow down tumor progression. All these provide a rationale to use PRLRA for two reasons (1) to reduce growth by blocking the PRLR JAK-STAT/AKT-PI3 pathways and (2) to use the PRLR to deliver rapamycin preferentially to GBM cells. Methodology: GBM cell line (U251-MG) obtained from ATCC, then we quantified levels of both PRL and PRLR in these cells. We used PRL induced STAT5 and SK6 phosphorylation as a standard read-out for PRL effects. Using this system, we tested how rapamycin interfere with PRL signals and we determined to what extent the PRLR antagonist facilitates action of rapamycin. Results: we found that PRLR are significantly expressed in U251-MG cells. PRLR antagonist block STAT5 phosphorylation and facilitate rapamycin effect on U251-MG cells by reduce S6k phosphorylation on dose dependent manner. Conclusion developing PRLR antagonist -rapamycin conjugate might open new line of GBM treatment by using the PRLR as delivering system for rapamycin. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.