Prolactin Receptor Expression Research Articles

ImmunoPET Imaging of Endogenous and Transfected Prolactin Receptor Tumor Xenografts.

Antibodies labeled with positron-emitting isotopes have been used for tumor detection, predicting which patients may respond to tumor antigen-directed therapy, and assessing pharmacodynamic effects of drug interventions. Prolactin receptor (PRLR) is overexpressed in breast and prostate cancers and is a new target for cancer therapy. We evaluated REGN2878, an anti-PRLR monoclonal antibody, as an immunoPET reagent. REGN2878 was labeled with Zr-89 after conjugation with desferrioxamine B or labeled with I-131/I-124. In vitro determination of the half-maximal inhibitory concentration (IC50) of parental REGN2878, DFO-REGN2878, and iodinated REGN2878 was performed by examining the effect of the increasing amounts of these on uptake of trace-labeled I-131 REGN2878. REGN1932, a non-PRLR binding antibody, was used as a control. Imaging and biodistribution studies were performed in mice bearing tumor xenografts with various expression levels of PRLR, including MCF-7, transfected MCF-7/PRLR, PC3, and transfected PC3/PRLR and T4D7v11 cell lines. The specificity of uptake in tumors was evaluated by comparing Zr-89 REGN2878 and REGN1932, and in vivo competition compared Zr-89 REGN2878 uptake in tumor xenografts with and without prior injection of 2 mg of nonradioactive REGN2878. The competition binding assay of DFO-REGN2878 at ratios of 3.53-5.77 DFO per antibody showed IC50 values of 0.4917 and 0.7136 nM, respectively, compared to 0.3455 nM for parental REGN2878 and 0.3343 nM for I-124 REGN2878. Imaging and biodistribution studies showed excellent targeting of Zr-89 REGN2878 in PRLR-positive xenografts at delayed times of 189 h (presented as mean ± 1 SD, percent injected activity per mL (%IA/mL) 74.6 ± 33.8%IA/mL). In contrast, MCF-7/PRLR tumor xenografts showed a low uptake (7.0 ± 2.3%IA/mL) of control Zr-89 REGN1932 and a very low uptake and rapid clearance of I-124 REGN2878 (1.4 ± 0.6%IA/mL). Zr-89 REGN2878 has excellent antigen-specific targeting in various PRLR tumor xenograft models. We estimated, using image-based kinetic modeling, that PRLR antigen has a very rapid in vivo turnover half-life of ∼14 min from the cell membrane. Despite relatively modest estimated tumor PRLR expression numbers, PRLR-expressing cells have shown final retention of the Zr-89 REGN2878 antibody, with an uptake that appeared to be related to PRLR expression. This reagent has the potential to be used in clinical trials targeting PRLR.

Quercetin improves postpartum hypogalactia in milk-deficient mice via stimulating prolactin production in pituitary gland.

Postpartum dysgalactia is a common clinical problem for lactating women. Seeking out the safe and efficient phytoestrogens will be a promising strategy for postpartum dysgalactia therapy. In this study, the postpartum mice within four groups, including control group, the model group, and the treatment groups intragastrically administrated with normal saline, bromocriptine, bromocriptine plus 17α-ethinyl estradiol, and bromocriptine plus quercetin, respectively, were used. The results showed that quercetin, a kind of natural phytoestrogen, could efficiently promote lactation yield and mammary gland development in the agalactosis mice produced by bromocriptine administration. Mechanically, quercetin, such as 17α-ethinyl estradiol, significantly stimulated prolactin (PRL) production and deposition in the mammary gland in the agalactosis mice determined by western blotting, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. Furthermore, quercetin could increase the expression of β-casein, stearoyl-CoA desaturase, fatty acid synthase, and α-lactalbumin in the breast tissues that are responsible for the production of fatty acid, lactose, and galactose in the milk at the transcriptional level determined by quantitative polymerase chain reaction. Specifically, quercetin promoted primary mammary epithelial cell proliferation and stimulated prolactin receptor (PRLR) expression probably via AKT activation in vitro. In conclusion, this study indicates that estrogen-like quercetin promotes mammary gland development and lactation yield in milk-deficient mice, probably via stimulating PRL expression and release from the pituitary gland, as well as induces PRLR expression in primary mammary epithelial cells.

The expression and clinical progression of androgen, estrogen and prolactin receptor in laryngeal squamous cell carcinoma

Objective:The aim of this study is to analyze the different expression and function of androgen receptors (AR) and estrogen receptor (ER-α) in laryngeal squamous cell carcinoma (LSCC). In combination with the expression of prolactin receptor (PRLR), we analyzed the prognostic impact of three receptors on the laryngeal carcinoma. Method:In this study, immunohistochemistry and reverse transcription polymerase chain reaction (RT-PC) analysis were performed on the tumor tissues and adjacent normal tissues in 112 LSCC patients (95 males and 17 females). We found that hormone receptor expression is closely related to the clinical tumor lesions and overall survival data. Result:The expression of AR, ER-α and PRLR in tumor tissues were much higher than those in adjacent normal tissues (P>0.05) at both protein and mRNA levels. The higher PRLR level indicate poor survival in LSCC patients (P=0.02), while higher ER-α expression could influence the survival with considerable trend toward significance (P=0.06). Furthermore, the higher expression of ER-α in tumours were corresponding with PRLR cytoplasmic higher level expression (r=0.802, P=0.04). This mutual promoted effect between ER-α and PRLR possibly suggests potential mechanisms among those sex related hormone receptors in laryngeal cancer. Conclusion:It has become increasingly credible that the sex related hormone receptors play an important role in the development of LSCC.

Impaired prolactin actions mediate altered offspring metabolism induced by maternal high-fat feeding during lactation.

Maternal diet during lactation affects offspring metabolic health throughout life. Prolactin (PRL) is present in high quantities in maternal milk; however, the effects of milk PRL on the offspring remain poorly characterized. In this study, we evaluated whether feeding a high-fat diet (HFD) to rats during lactation alters PRL, both in the mother's serum and in milk, and whether this factor contributes to HFD-induced metabolic dysfunction in the offspring. Maternal HFD resulted in decreased PRL levels in milk (but not in serum), reduced mammary gland (MG) PRL receptor expression, and altered MG structure and function. Offspring from HFD-fed dams had increased body weight and adiposity, and developed fatty liver, hyperinsulinemia, and insulin resistance at weaning. Increasing PRL levels in the HFD-fed mothers by subcutaneous osmotic minipumps releasing PRL normalized MG function and PRL levels in milk. Moreover, PRL treatment in HFD-fed mothers, or directly in their pups via oral PRL administration, increased liver STAT5 phosphorylation, reduced visceral adiposity, ameliorated fatty liver, and improved insulin sensitivity in offspring. Our results show that HFD impairs PRL actions during lactation to negatively affect MG physiology and directly impair offspring metabolism.-De los Ríos, E. A., Ruiz-Herrera, X., Tinoco-Pantoja, V., López-Barrera, F., Martínez de la Escalera, G., Clapp, C., Macotela, Y. Impaired prolactin actions mediate altered offspring metabolism induced by maternal high-fat feeding during lactation.

Effect of Total Flavones from Cuscuta Chinensis on Anti-Abortion via the MAPK Signaling Pathway.

For centuries, the Chinese herb Cuscuta chinensis has been applied clinically for abortion prevention in traditional Chinese medicine (TCM). Total flavones extracted from Cuscuta chinensis (TFCC) are one of the active components in the herb and also display anti-abortion effect similar to the unprocessed material. However, how TFCC exerts the anti-abortion effect remains largely unknown. In this study, we aim at characterizing the anti-abortion effects of TFCC and its underlying molecular mechanism in vitro and in vivo using human primary decidua cells and a mifepristone-induced abortion model in rat, respectively. The damage to the decidua caused by mifepristone in vivo was reversed by TFCC treatment in a dosage-dependent manner. High dosage of TFCC significantly upregulated the expression of estrogen receptor (ER), progesterone receptor (PR), and prolactin receptor (PRLR) in decidua tissue but downregulated the expression of p-ERK. Furthermore, we detected higher level of p-ERK and p-p38 in primary decidua cells from spontaneous abortion while treatment by TFCC downregulated their expression. Our results suggest TFCC mediates its anti-abortion effect by interfering with MAPK signaling pathway.

Effects of acupuncture combined with Rule granule on breast tissue, prolactin and receptor expression in rats with mammary gland hyperplasia

To observe the effects of acupuncture combined with Rule granule on breast tissue, prolactin(PRL) and prolactin receptor (PRLR) expression in rats with mammary gland hyperplasia (MGH), and to explore its action mechanism to provide reference for clinical treatment of MGH. Fifty-five female SD rats were randomly divided into a blank group, a model group, an acupuncture group, a Rule granule group and a combination group. Except the blank group, the rats in the remaining groups were treated with combined stimulation of estrogenic and progestational hormone to establish MGH model. After model establishment, the rats in the acupuncture group were treated with acupuncture at Plan A of "Tianzong" (SI 11), "Ganshu" (BL 18), "Zusanli" (ST 36) and Plan B of "Wuyi" (ST 15), "Hegu" (LI 4), "Danzhong" (CV 17). Each plan was selected for one acupuncture treatment, and two plans were used alternately. The rats in the Rule granule group were treated with oral administration of granule, 3 mL per times. The rats in the combination group were treated with the same Rule granule, followed by acupuncture, once a day. After consecutive 30-day treatment, blood sample was collected from abdominal aorta; ELISA method was applied to measure the contents of PRL; the HE slice of mammary gland was observed under light microscope; the SABC immunohistochemical method was applied to measure the positive expression of PRLR. The morphology of breast tissue in the model group was consistent with MGH. Compared with the blank group, the serum PRL and the expression of PRLR were increased significantly in the model group (both P<0.01). Compared with the model group, the hyperplasia of mammary gland in each treatment group was improved, and serum PRL and expression of PRLR were significantly reduced (P<0.05, P<0.01), which were more significant in the combination group (both P<0.05). Acupuncture, Rule granule and its combination could effectively treat MGH, which is likely to reduce the level of serum PRL and inhibit the binding of PRL to PRLR, as a result, the level of E2 is indirectly inhibited, and the hyperplastic mammary gland is recovered. Compared with acupuncture or Rule granule, the combination of both has better overall efficacy.

Sex-related hormone receptor in laryngeal squamous cell carcinoma: correlation with androgen estrogen-ɑ and prolactin receptor expression and influence of prognosis

Background: The expression and function of androgen receptors (AR) and estrogen receptor alpha (ER-ɑ) in laryngeal squamous cell carcinoma (LSCC) have remained controversial for decades. Prolactin receptor (PRLR) is a sex-related hormone, that has been rarely documented in terms of expression or function compared with data on other hormone receptors in laryngeal carcinoma.Methods: This study reports on immunohistochemical and reverse transcription-polymerase chain reaction (RT-PCR) analysis of tumour tissue and adjacent normal tissue in 96 patients with LSCC (82 males and 14 females). The expression levels of the receptors were related to clinicopathologic parameters and survival data.Results: At both protein and mRNA levels, the expression level of AR, ER-ɑ, and PRLR was much higher in LSCC than in adjacent normal tissues (p < .05). Among them, higher PRLR expression in tumour tissues tended to have a significantly poorer survival rate (p = .03) for patients with LSCC. Furthermore, higher expression of ER-ɑ in tumours was correlated with higher expression level of PRLR (r = .823, p = .03).Conclusion: The findings of this study indicate that the sex-related hormone receptors play an important role in the development of LSCC. The PRLR represents a novel prognosticator, because of its negative effect on survival and its interaction with ER-ɑ.

Isoflavones and their metabolites influence the milk component synthesis ability of mammary epithelial cells through prolactin/STAT5 signaling.

Isoflavones are a class of polyphonic compounds present in legumes and are called phytoestrogens because of their estrogen-like activity. Estrogen influences the behavior of mammary epithelial cells (MECs) during pregnancy and lactation. In this study, we investigated the direct influences of isoflavones and their metabolites in milk production ability of MECs. Mouse MECs were cultured with prolactin and dexamethasone (glucocorticoid analog) to induce milk production ability. Subsequently, lactating MECs were treated with each isoflavone. Coumestrol, biochanin A, genistein, and formononetin decreased the intracellular and secreted β-casein. On the other hand, p-ethylphenol, daidzein, and equol did not significantly influence β-casein production at any concentration. Coumestrol, biochanin A and genistein down-regulated the mRNA expression of whey acidic protein (WAP), lactoferrin and α-lactalbumin. In contrast, p-ethylphenol, daidzein and equol up-regulated β-casein and/or WAP with α-lactalbumin. Furthermore, coumestrol and genistein down-regulated the expression of prolactin receptor and signal transducer and activator of transcription 5 (STAT5) accompanied by a decrease in STAT5 phosphorylation. Isoflavones and their metabolites influence the milk production ability of MECs through different interactions with prolactin/STAT5 signaling. Simultaneous intake of multiple isoflavones by consumption of legumes may induce promotive or adverse effects on lactating MECs.

Understanding the Inguinal Sinus in Sheep (Ovis aries)-Morphology, Secretion, and Expression of Progesterone, Estrogens, and Prolactin Receptors.

Post-parturient behavior of mammalian females is essential for early parent–offspring contact. After delivery, lambs need to ingest colostrum for obtaining the related immunological protection, and early interactions between the mother and the lamb are crucial. Despite visual and auditory cues, olfactory cues are decisive in lamb orientation to the mammary gland. In sheep, the inguinal sinus is located bilaterally near the mammary gland as a skin pouch (IGS) that presents a gland that secretes a strong-smelling wax. Sheep IGS gland functions have many aspects under evaluation. The objective of the present study was to evaluate sheep IGS gland functional aspects and mRNA transcription and the protein expression of several hormone receptors, such as progesterone receptor (PGR), estrogen receptor 1 (ESR1), and 2 (ESR2) and prolactin receptor (PRLR) present. In addition, another aim was to achieve information about IGS ultrastructure and chemical compounds produced in this gland. All hormone receptors evaluated show expression in IGS during the estrous cycle (follicular/luteal phases), pregnancy, and the post-partum period. IGS secretion is rich in triterpenoids that totally differ from the surrounding skin. They might be essential substances for the development of an olfactory preference of newborns to their mothers.

Effects of Pup Separation on Stress Response in Postpartum Female Rats.

There is a complex collection of neuroendocrine function during the postpartum period. Prolactin (PRL) released by suckling stimulus and its PRL receptors (PRL-R) in the central nervous system (CNS) are involved in hyporesponsiveness of the hypothalamic-pituitary-adrenal (HPA) axis in lactating mammals including rodents and humans. It is not clear how long it takes to reestablish the attenuated HPA axis activity of lactating rats to a pre-pregnancy state after pup separation. We first tested the hypothesis that HPA axis activity in response to an acute stress in postpartum rats would return to a pre-pregnancy state after pup separation. Restraint stress for 30 min was performed at the end of pup separation as an acute stressor. Plasma levels of corticosterone (CORT) were measured following restraint stress or no-stress (control) in virgin rats and postpartum rats housed with their pups or with pup removal for different periods of time of one hour, 24 h, or eight days. We then tested the hypothesis that circulating PRL level and CNS PRL-R gene expression were involved in mediating the acute stress response in postpartum rats. Plasma levels of PRL and PRL-R mRNA levels in the choroid plexus of the CNS were determined in both no-stress and stress, virgin rats, and postpartum rats housed with their pups or with pup removal for various periods, and their correlation with plasma CORT levels was assessed. The results demonstrated that PRL levels declined to virgin state in all postpartum rats separated from their pups, including the dams with one-hour pup separation. Stress-induced HPA activity dampened in lactating rats housed with pups, and returned to the pre-pregnancy state after 24 h of pup separation when both circulating PRL level and CNS PRL-R expression were restored to a pre-pregnancy state. Additionally, basal plasma CORT and CNS PRL-R expression were significantly correlated in rats with various pup status. This study suggested that stress-induced HPA activation occurred when PRL-R expression was similar to the level of virgin females, indicating that PRL-R upregulation contributes to an attenuated HPA response to acute stress. Understanding neuroendocrine responses to stress during the postpartum period is critical to understand postpartum-related neuropsychiatric illnesses and to maintain mental health in postpartum women.

A pilot phase II trial of cabergoline in the treatment of metastatic breast cancer.

e12568 Background: The prolactin receptor can be overexpressed in breast cancer, and pre-clinical data indicate that it contributes to the pathobiology of breast cancer. Cabergoline is a potent dopamine receptor agonist of D2 receptors and has a direct inhibitory effect on pituitary prolactin secretion resulting in reduced serum prolactin levels. Methods: A pilot phase II study of cabergoline in patients with metastatic breast cancer was conducted with primary end point of best overall response rate (ORR) among patients with measurable disease. Eligible patients had metastatic breast cancer, any receptors status was allowed, and there was no limit of prior lines of therapy. Both measurable and unmeasurable diseases (RECIST 1.1) were allowed. Cabergoline 1mg orally, twice weekly (1 cycle = 4 weeks) was given until disease progression or unacceptable toxicity. Immunohistochemistry prolactin receptor staining was performed on available baseline tumor tissue, and serum prolactin levels were serially assessed. Results: A total of 20 women were enrolled, 19 of whom were evaluable for response (one patient died on C1D7 of unrelated causes). Mean age was 62 (range 42-83); 15 (75%) were Caucasian; mean number of prior lines of therapy 5 (range 0-14). Tumor receptor statuses were distributed as follows: HR+/HER2+ 1(5%), HR+/HER2- 18 (80%), HR-/HER2+ 1 (5%). Analysis was performed after a median follow-up of 6.8 months (0.2-26.2). Best ORR was 8.3% among 12 patients with measurable disease. Results for secondary endpoints were as follows: 4-month CBR = 26% (including patients with measurable and non-measurable disease), median PFS = 1.9 months, and median OS = 10.4 months. Most common treatment related AEs were nausea (30%), fatigue (25%), and elevation in alkaline phosphatase (15%). The highest-grade AE was a single grade 3 treatment-related pain in extremity. Nine patients had sufficient baseline tissue for analysis, there was no correlation between baseline tumor prolactin receptor expression and clinical benefit ( p= 0.24). Additional correlative work is ongoing. Conclusions: Cabergoline was well tolerated and associated with modest anti-tumor activity. Clinical trial information: NCT01730729.

Prolactin modulates luteal activity in the short-nosed fruit bat, Cynopterus sphinx during delayed embryonic development

The aim of this study was to evaluate the role of prolactin as a modulator of luteal steroidogenesis during the period of delayed embryonic development in Cynopterus sphinx. A marked decline in circulating prolactin levels was noted during the months of November through December coinciding with the period of decreased serum progesterone and delayed embryonic development. The seasonal changes in serum prolactin levels correlated positively with circulating progesterone (P) level, but inversely with circulating melatonin level during first pregnancy showing delayed development in Cynopterus sphinx. The results also showed decreased expression of prolactin receptor-short form (PRL-RS) both in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. Bats treated in vivo with prolactin during the period of delayed development showed significant increase in serum progesterone and estradiol levels together with significant increase in the expression of PRL-RS, luteinizing hormone receptor (LH-R), steroidogenic acute receptor protein (STAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) in the ovary. Prolactin stimulated ovarian angiogenesis (vascular endothelial growth factor) and cell survival (B-cell lymphoma 2) in vivo. Significant increases in ovarian progesterone production and the expression of prolactin-receptor, LH-R, STAR and 3β-HSD proteins were noted following the exposure of LH or prolactin in vitro during the delayed period. In conclusion, short-day associated increased melatonin level may be responsible for decreased prolactin release during November–December. The decline in prolactin level might play a role in suppressing P and estradiol-17β (E2) estradiol levels thereby causing delayed embryonic development in C. sphinx.

Hypothyroidism decreases JAK/STAT signaling pathway in lactating rat mammary gland

Thyroid pathologies have deleterious effects on lactation. Especially hypothyroidism (HypoT) induces premature mammary involution at the end of lactation and decreases milk production and quality in mid lactation. Milk synthesis is controlled by JAK2/STAT5 signaling pathway and prolactin (PRL), which activates the pathway. In this work we analyzed the effect of chronic 6-propyl-2-thiouracil (PTU)-induced HypoT on PRL signaling pathway on mammary glands from rats on lactation (L) days 2, 7 and 14. HypoT decreased prolactin receptor expression, and expression and activation of Stat5a/b protein. Expression of members of the SOCS-CIS family, inhibitors of the JAK-STAT pathway, decreased in L2 and L7, possibly as a compensatory response of the mammary cells to maintain PRL responsiveness. However, on L14, the level of these inhibitors was normal and the transcription of α-lactoalbumin (lalba), a target gene of the PRL pathway, decreased by half. HypoT altered the transcriptional capacity of the cell and decreased mRNA levels of Prlr and Stat5b on L14. Stat5b gene has functional thyroid hormone response elements in the regulatory regions, that bind thyroid hormone receptor β (TRβ) differentially and in a thyroid hormone dependent manner. The overall decrease in the PRL signaling pathway and consequently in target gene (lalba) mRNA transcription explain the profound negative impact of HypoT on mammary function through lactation.

Effects of dietary octacosanol supplementation on laying performance, egg quality, serum hormone levels, and expression of genes related to the reproductive axis in laying hens

This experiment was conducted to evaluate the effects of dietary octacosanol supplementation on laying performance, egg quality, serum hormone levels, and gene expression related to reproductive axis in laying hens to confirm the reproduction-promoting function of octacosanol. In total, 360 Hy-Line Brown (67-wk-old) laying hens were randomly assigned to one of three treatments with 0, 5, and 10 mg octacosanol (extracted from rice bran, purity >92%)/kg feed. The feeding trial lasted for 10 weeks. The results showed that the dietary addition of 5 and 10 mg/kg octacosanol improved feed efficiency by 4.9% and 3.4% (P < 0.01), increased the albumen height by 20.5% and 13.3% (P < 0.01), the Haugh unit score by 12.9% and 8.7% (P < 0.01), and the eggshell strength by 39.5% and 24.5% (P < 0.01), respectively, compared with the control diet. Dietary octacosanol addition significantly affected serum triiodothyronine, estradiol, follicle-stimulating hormone levels (P < 0.05), and progesterone and luteinizing hormone level (P < 0.01). Compared with the control, dietary addition of octacosanol at 5 mg/kg promoted the follicle-stimulating hormone receptor (FSHR) mRNA expression in different-sized follicles, and significantly increased the FSHR mRNA expression of granulosa cells from the F2 and F3 follicles (P < 0.05). Dietary supplementation with both 5 and 10 mg/kg octacosanol promoted the mRNA expression of luteinizing hormone receptor and prolactin receptor in different-sized follicles, and significantly up-regulated the expression levels in F1 granulosa cells (P < 0.05). The ovarian weight was significantly increased with the dietary addition of 5 mg/kg octacosanol (P < 0.05). The numbers of small yellow follicles and large white follicles were increased with the addition of dietary 5 and 10 mg/kg octacosanol (P < 0.01). This study provides evidence that octacosanol has the capacity to improve reproductive performance, indicating that it is a potentially effective feed additive in egg production.

Seasonal expressions of follicle-stimulating hormone receptor and luteinizing hormone receptor in the scented gland of the male muskrat (Ondatra zibethicus).

Accumulating evidence has shown that follicle-stimulating hormone (FSH) and luteinizing hormone (LH) may influence the functions of nongonadal tissues in addition to their classic target gonads. Our previous studies revealed that the scented glands of male muskrats expressed prolactin receptor, steroidogenic enzymes, and inhibin/activin subunits. To further seek the evidence of the activities of pituitary gonadotropins in scented glands, we investigated the seasonal expression patterns of FSH receptor (FSHR) and LH/choriogonadotropin receptor (LHCGR). The weight and size of scented glands during the breeding season were significantly higher than those during the nonbreeding season. Immunohistochemical studies showed that FSHR was present in the serous cells of scented glands, whereas LHCGR was present in the interstitial cells. The protein and mRNA expression levels of FSHR and LHCGR were significantly higher in the scented glands during the breeding season than those during the nonbreeding season. Importantly, the levels of circulating FSH and LH were remarkably higher during the breeding season. Taken together, these results suggested that gonadotropins may affect the function of muskrat scented gland via the locally expressed receptors in a season-dependent manner.

The expression of prolactin receptor and its ligands in ovarian epithelial tumours

The expression of prolactin receptor and its ligands in ovarian epithelial tumours

Regulatory Mechanisms Underlying the Expression of Prolactin Receptor in Chicken Granulosa Cells

Prolactin (PRL) has both pro- and anti-gonadal roles in the regulation of avian ovarian functions through its interaction with the receptor (PRLR). However, neither the pattern of expression of PRLR nor its regulatory mechanisms during follicle development have been clearly defined. The objective of the present study was to investigate mechanisms of PRLR expression in chicken granulosa cells. Levels of PRLR transcript were highest in the stroma and walls of follicles < 2 mm in diameter and progressively declined with the maturation of follicles. In preovulatory follicles, PRLR was expressed at higher levels in granulosa than theca layers. FSH exerted the greatest stimulatory effect on PRLR and StAR expression in cultured granulosa cells of the 6–8 mm follicles but this effect declined as follicles matured to F1. In contrast, LH did not alter the expression of PRLR in granulosa cells of all follicular classes but increased levels of StAR in F2 and F1 granulosa cells. Both non-glycosylated- (NG-) and glycosylated- (G-) PRL upregulated basal PRLR expression in granulosa cells of the 6–8 mm, F3 or F1 follicles but had little effect in F2 follicles. Furthermore, FSH-stimulated PRLR expression was reduced by the addition of either isoform of PRL especially in F2 granulosa cells. These results indicate that PRLR is differentially distributed and regulated by FSH or PRL variants independently or in combination in the follicular hierarchy. By using activators and inhibitors, we further demonstrated that multiple signaling pathways, including PKA, PKC, PI3K, mTOR and AMPK, are not only directly involved in, but they can also converge to modulate ERK2 activity to regulate FSH-mediated PRLR and StAR expression in undifferentiated granulosa cells. These data provide new insights into the regulatory mechanisms controlling the expression of PRLR in granulosa cells.

Elevated collagen-I augments tumor progressive signals, intravasation and metastasis of prolactin-induced estrogen receptor alpha positive mammary tumor cells

BackgroundThe development and progression of estrogen receptor alpha positive (ERα+) breast cancer has been linked epidemiologically to prolactin. However, activation of the canonical mediator of prolactin, STAT5, is associated with more differentiated cancers and better prognoses. We have reported that density/stiffness of the extracellular matrix potently modulates the repertoire of prolactin signals in human ERα + breast cancer cells in vitro: stiff matrices shift the balance from the Janus kinase (JAK)2/STAT5 cascade toward pro-tumor progressive extracellular regulated kinase (ERK)1/2 signals, driving invasion. However, the consequences for behavior of ERα + cancers in vivo are not known.MethodsIn order to investigate the importance of matrix density/stiffness in progression of ERα + cancers, we examined tumor development and progression following orthotopic transplantation of two clonal green fluorescent protein (GFP) + ERα + tumor cell lines derived from prolactin-induced tumors to 8-week-old wild-type FVB/N (WT) or collagen-dense (col1a1tm1Jae/+) female mice. The latter express a mutant non-cleavable allele of collagen 1a1 “knocked-in” to the col1a1 gene locus, permitting COL1A1 accumulation. We evaluated the effect of the collagen environment on tumor progression by examining circulating tumor cells and lung metastases, activated signaling pathways by immunohistochemistry analysis and immunoblotting, and collagen structure by second harmonic generation microscopy.ResultsERα + primary tumors did not differ in growth rate, histologic type, ERα, or prolactin receptor (PRLR) expression between col1a1tm1Jae/+ and WT recipients. However, the col1a1tm1Jae/+ environment significantly increased circulating tumor cells and the number and size of lung metastases at end stage. Tumors in col1a1tm1Jae/+ recipients displayed reduced STAT5 activation, and higher phosphorylation of ERK1/2 and AKT. Moreover, intratumoral collagen fibers in col1a1tm1Jae/+ recipients were aligned with tumor projections into the adjacent fat pad, perpendicular to the bulk of the tumor, in contrast to the collagen fibers wrapped around the more uniformly expansive tumors in WT recipients.ConclusionsA collagen-dense extracellular matrix can potently interact with hormonal signals to drive metastasis of ERα + breast cancers.

Differential gene expression in patients with anal fistula reveals high levels of prolactin recepetor

Background/Aim. There are limited data examining variations in the local expression of inflammatory mediators in anal fistulas where it is anticipated that an improved understanding of the inflammatory milieu might lead to the potential therapeutic option of instillation therapy in complicated cases. The aim of the present study was to examine prolactin receptors (PRLR) as inflammatory markers and to correlate their expression with both the complexity of anal fistulas and the likelihood of fistula recurrence. Methods. Microarray was used to screen the differentially expressed gene profile of anal fistula using anal mucosa samples with hemorrhoids with ageand sex-matched patients as controls and then a prospective analysis of 65 patients was conducted with anal fistulas. PRLR immunohistochemistry was performed to define expression in simple, complex and recurrent anal fistula cases. The quantitative image comparison was performed combining staining intensity with cellular distribution in order to create high and low score PRLR immunohistochemical groupings. Results. A differential expression profile of 190 genes was found. PRLR expression was 2.91 times lower in anal fistula compared with control. Sixty-five patients were assessed (35 simple, 30 complex cases). Simple fistulas showed significantly higher PRLR expression than complex cases with recurrent fistulae showing overall lower PRLR expression than de novo cases (p = 0.001). These findings were reflected in measurable integrated optical density for complex and recurrent cases (complex cases, 8.31 ? 4.91 x 104 vs simple cases, 12.30 ? 6.91 x 104; p &lt; 0.01; recurrent cases, 7.21 ? 3.51 x 104 vs primarily healing cases, 8.31 ? 4.91 x 104; p &lt; 0.05). In univariate regression analysis, low PRLR expression correlated with fistula complexity; a significant independent effect maintained in multivariate analysis odds ratio [(OR) low to high PRLR expression = 9.52; p = 0.001)]. Conclusion. PRLR expression inversely correlates with anal fistula complexity. Further work must define the specificity of this finding and its relationship to other conventional mediators of inflammation.

Effect of hyperthyroidism on circulating prolactin and hypothalamic expression of tyrosine hydroxylase, prolactin signaling cascade members and estrogen and progesterone receptors during late pregnancy and lactation in the rat

Hyperthyroidism (HyperT) compromises pregnancy and lactation, hindering suckling-induced PRL release. We studied the effect of HyperT on hypothalamic mRNA (RT-qPCR) and protein (Western blot) expression of tyrosine hydroxylase (TH), PRL receptor (PRLR) and signaling pathway members, estrogen-α (ERα) and progesterone (PR) receptors on late pregnancy (days G19, 20 and 21) and early lactation (L2) in rats. HyperT advanced pre-partum PRL release, reduced circulating PRL on L2 and increased TH mRNA (G21 and L2), p-TH, PRLR mRNA, STAT5 protein (G19 and L2), PRLR protein (G21) and CIS protein (G19). PRs mRNAs and protein decreased on G19 but afterwards PRA mRNA (G20), PRB mRNA (G21) and PRA mRNA and protein (L2) increased. ERα protein increased on G19 and decreased on G20. Thus, the altered hypothalamic PRLR, STAT5, PR and ERα expression in hyperthyroid rats may induce elevated TH expression and activation, that consequently, elevate dopaminergic tone during lactation, blunting suckling-induced PRL release and litter growth.