1
|
Standing D, Dandawate P, Anant S. Prolactin receptor signaling: A novel target for cancer treatment - Exploring anti-PRLR signaling strategies. Front Endocrinol (Lausanne) 2022; 13:1112987. [PMID: 36714582 PMCID: PMC9880166 DOI: 10.3389/fendo.2022.1112987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/22/2022] [Indexed: 01/15/2023] Open
Abstract
Prolactin (PRL) is a peptide hormone mainly secreted from the anterior pituitary gland. PRL is reported to play a role in pregnancy, mammary gland development, immune modulation, reproduction, and differentiation of islet cells. PRL binds to its receptor PRLR, which belongs to a superfamily of the class I cytokine receptor that has no intrinsic kinase activity. In canonical signaling, PRL binding to PRLR induces downstream signaling including JAK-STAT, AKT and MAPK pathways. This leads to increased cell proliferation, stemness, migration, apoptosis inhibition, and resistance to chemotherapy. PRL-signaling is upregulated in numerous hormone-dependent cancers including breast, prostate, ovarian, and endometrial cancer. However, more recently, the pathway has been reported to play a tumor-promoting role in other cancer types such as colon, pancreas, and hepatocellular cancers. Hence, the signaling pathway is an attractive target for drug development with blockade of the receptor being a potential therapeutic approach. Different strategies have been developed to target this receptor including modification of PRL peptides (Del1-9-G129R-hPRL, G129R-Prl), growth hormone receptor/prolactin receptor bispecific antibody antagonist, neutralizing antibody LFA102, an antibody-drug conjugate (ABBV-176) of the humanized antibody h16f (PR-1594804) and pyrrolobenzodiazepine dimer, a bispecific antibody targeting both PRLR and CD3, an in vivo half-life extended fusion protein containing PRLR antagonist PrlRA and albumin binding domain. There have also been attempts to discover and develop small molecular inhibitors targeting PRLR. Recently, using structure-based virtual screening, we identified a few antipsychotic drugs including penfluridol as a molecule that inhibits PRL-signaling to inhibit PDAC tumor progression. In this review, we will summarize the recent advances in the biology of this receptor in cancer and give an account of PRLR antagonist development for the treatment of cancer.
Collapse
|
2
|
Suzuki MF, Almeida LA, Pomin SA, Silva FD, Freire RP, Oliveira JE, Affonso R, Soares CRJ, Bartolini P. Periplasmic synthesis and purification of the human prolactin antagonist Δ 1-11-G129R-hPRL. AMB Express 2021; 11:62. [PMID: 33905023 PMCID: PMC8079533 DOI: 10.1186/s13568-021-01209-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 11/30/2022] Open
Abstract
The human prolactin antagonist Δ1-11-G129R-hPRL is a 21.9 kDa recombinant protein with 188 amino acids that downregulates the proliferation of a variety of cells expressing prolactin receptors. Periplasmic expression of recombinant proteins in E. coli has been considered an option for obtaining a soluble and correctly folded protein, as an alternative to cytoplasmic production. The aim of this work was, therefore, to synthesize for the first time, the Δ1-11-G129R-hPRL antagonist, testing different activation temperatures and purifying it by classical chromatographic techniques. E. coli BL21(DE3) strain was transformed with a plasmid based on the pET25b( +) vector, DsbA signal sequence and the antagonist cDNA sequence. Different doses of IPTG were added, activating under different temperatures, and extracting the periplasmic fluid via osmotic shock. The best conditions were achieved by activating at 35 °C for 5 h using 0.4 mM IPTG, which gave a specific expression of 0.157 ± 0.015 μg/mL/A600 at a final optical density of 3.43 ± 0.13 A600. Purification was carried out by nickel-affinity chromatography followed by size-exclusion chromatography, quantification being performed via high-performance size-exclusion chromatography (HPSEC). The prolactin antagonist was characterized by SDS-PAGE, Western blotting, reversed-phase high-performance liquid chromatography (RP-HPLC) and MALDI-TOF–MS. The final product presented > 95% purity and its antagonistic effects were evaluated in vitro in view of potential clinical applications, including inhibition of the proliferation of cancer cells overexpressing the prolactin receptor and specific antidiabetic properties, taking also advantage of the fact that this antagonist was obtained in a soluble and correctly folded form and without an initial methionine.
Collapse
|
3
|
Menendez JA, Peirce SK, Papadimitropoulou A, Cuyàs E, Steen TV, Verdura S, Vellon L, Chen WY, Lupu R. Progesterone receptor isoform-dependent cross-talk between prolactin and fatty acid synthase in breast cancer. Aging (Albany NY) 2020; 12:24671-24692. [PMID: 33335078 PMCID: PMC7803566 DOI: 10.18632/aging.202289] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/27/2020] [Indexed: 04/13/2023]
Abstract
Progesterone receptor (PR) isoforms can drive unique phenotypes in luminal breast cancer (BC). Here, we hypothesized that PR-B and PR-A isoforms differentially modify the cross-talk between prolactin and fatty acid synthase (FASN) in BC. We profiled the responsiveness of the FASN gene promoter to prolactin in T47Dco BC cells constitutively expressing PR-A and PR-B, in the PR-null variant T47D-Y cell line, and in PR-null T47D-Y cells engineered to stably re-express PR-A (T47D-YA) or PR-B (T47D-YB). The capacity of prolactin to up-regulate FASN gene promoter activity in T47Dco cells was lost in T47D-Y and TD47-YA cells. Constitutively up-regulated FASN gene expression in T47-YB cells and its further stimulation by prolactin were both suppressed by the prolactin receptor antagonist hPRL-G129R. The ability of the FASN inhibitor C75 to decrease prolactin secretion was more conspicuous in T47-YB cells. In T47D-Y cells, which secreted notably less prolactin and downregulated prolactin receptor expression relative to T47Dco cells, FASN blockade resulted in an augmented secretion of prolactin and up-regulation of prolactin receptor expression. Our data reveal unforeseen PR-B isoform-specific regulatory actions in the cross-talk between prolactin and FASN signaling in BC. These findings might provide new PR-B/FASN-centered predictive and therapeutic modalities in luminal intrinsic BC subtypes.
Collapse
MESH Headings
- 4-Butyrolactone/analogs & derivatives
- 4-Butyrolactone/pharmacology
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Carcinoma, Ductal, Breast/genetics
- Carcinoma, Ductal, Breast/metabolism
- Cell Line, Tumor
- Databases, Genetic
- Fatty Acid Synthase, Type I/antagonists & inhibitors
- Fatty Acid Synthase, Type I/genetics
- Fatty Acid Synthase, Type I/metabolism
- Humans
- Interleukin-6/metabolism
- Prolactin/metabolism
- Prolactin/pharmacology
- Promoter Regions, Genetic
- Protein Isoforms
- RNA, Messenger/metabolism
- Receptor Cross-Talk
- Receptors, Progesterone/genetics
- Receptors, Progesterone/metabolism
- Receptors, Prolactin/antagonists & inhibitors
- Receptors, Prolactin/genetics
- Receptors, Prolactin/metabolism
- Up-Regulation
Collapse
Affiliation(s)
- Javier A. Menendez
- Program Against Cancer Therapeutic Resistance (ProCURE), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona, Spain
- Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | | | | | - Elisabet Cuyàs
- Program Against Cancer Therapeutic Resistance (ProCURE), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona, Spain
- Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Travis Vander Steen
- Mayo Clinic, Division of Experimental Pathology, Department of Laboratory Medicine and Pathology, Rochester, MN 55905, USA
| | - Sara Verdura
- Program Against Cancer Therapeutic Resistance (ProCURE), Metabolism and Cancer Group, Catalan Institute of Oncology, Girona, Spain
- Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Luciano Vellon
- Stem Cells Laboratory, Institute of Biology and Experimental Medicine (IBYME-CONICET), Buenos Aires, Argentina
| | - Wen Y. Chen
- Department of Biological Sciences, Clemson University, Greenville, SC 29634, USA
| | - Ruth Lupu
- Mayo Clinic, Division of Experimental Pathology, Department of Laboratory Medicine and Pathology, Rochester, MN 55905, USA
- Mayo Clinic Minnesota, Department of Biochemistry and Molecular Biology Laboratory, Rochester, MN 55905, USA
- Mayo Clinic Cancer Center, Rochester, MN 55905, USA
| |
Collapse
|
4
|
Yu S, Alkharusi A, Norstedt G, Gräslund T. An in vivo half-life extended prolactin receptor antagonist can prevent STAT5 phosphorylation. PLoS One 2019; 14:e0215831. [PMID: 31063493 PMCID: PMC6504076 DOI: 10.1371/journal.pone.0215831] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/09/2019] [Indexed: 12/31/2022] Open
Abstract
Increasing evidence suggests that signaling through the prolactin/prolactin receptor axis is important for stimulation the growth of many cancers including glioblastoma multiforme, breast and ovarian carcinoma. Efficient inhibitors of signaling have previously been developed but their applicability as cancer drugs is limited by the short in vivo half-life. In this study, we show that a fusion protein, consisting of the prolactin receptor antagonist PrlRA and an albumin binding domain for half-life extension can be expressed as inclusion bodies in Escherichia coli and efficiently refolded and purified to homogeneity. The fusion protein was found to have strong affinity for the two intended targets: the prolactin receptor (KD = 2.3±0.2 nM) and mouse serum albumin (KD = 0.38±0.01 nM). Further investigation showed that it could efficiently prevent prolactin mediated phosphorylation of STAT5 at 100 nM concentration and above, similar to the PrlRA itself, suggesting a potential as drug for cancer therapy in the future. Complexion with HSA weakened the affinity for the receptor to 21±3 nM, however the ability to prevent phosphorylation of STAT5 was still prominent. Injection into rats showed a 100-fold higher concentration in blood after 24 h compared to PrlRA itself.
Collapse
Affiliation(s)
- Shengze Yu
- Department of Protein Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Amira Alkharusi
- College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Gunnar Norstedt
- College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman
- Center for Molecular Medicine, Karolinska Institute, Solna, Stockholm, Sweden
| | - Torbjörn Gräslund
- Department of Protein Science, KTH Royal Institute of Technology, Stockholm, Sweden
- * E-mail:
| |
Collapse
|
5
|
López-Ozuna VM, Hachim IY, Hachim MY, Lebrun JJ, Ali S. Prolactin Pro-Differentiation Pathway in Triple Negative Breast Cancer: Impact on Prognosis and Potential Therapy. Sci Rep 2016; 6:30934. [PMID: 27480353 PMCID: PMC4969612 DOI: 10.1038/srep30934] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/11/2016] [Indexed: 12/22/2022] Open
Abstract
Triple negative breast cancer (TNBC) is a heterogeneous disease associated with poor clinical outcome and lack of targeted therapy. Here we show that prolactin (PRL) and its signaling pathway serve as a sub-classifier and predictor of pro-differentiation therapy in TNBC. Using immunohistochemistry and various gene expression in silica analyses we observed that prolactin receptor (PRLR) protein and mRNA levels are down regulated in TNBC cases. In addition, examining correlation of PRLR gene expression with metagenes of TNBC subtypes (580 cases), we found that PRLR gene expression sub-classifies TNBC patients into a new subgroup (TNBC-PRLR) characterized by epithelial-luminal differentiation. Importantly, gene expression of PRL signaling pathway components individually (PRL, PRLR, Jak2 and Stat5a), or as a gene signature is able to predict TNBC patients with significantly better survival outcomes. As PRL hormone is a druggable target we determined the biological role of PRL in TNBC biology. Significantly, restoration/activation of PRL pathway in TNBC cells representative of mesenchymal or TNBC-PRLR subgroups led to induction of epithelial phenotype and suppression of tumorigenesis. Altogether, these results offer potential new modalities for TNBC stratification and development of personalized therapy based on PRL pathway activation.
Collapse
Affiliation(s)
- Vanessa M López-Ozuna
- Department of Medicine, Cancer Research Program, McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Ibrahim Y Hachim
- Department of Medicine, Cancer Research Program, McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Mahmood Y Hachim
- Medical Microbiology Department, RAK Medical and Health Sciences University, UAE
| | - Jean-Jacques Lebrun
- Department of Medicine, Cancer Research Program, McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Suhad Ali
- Department of Medicine, Cancer Research Program, McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| |
Collapse
|
6
|
Tao J, Oladimeji P, Rider L, Diakonova M. PAK1-Nck regulates cyclin D1 promoter activity in response to prolactin. Mol Endocrinol 2011; 25:1565-78. [PMID: 21719533 DOI: 10.1210/me.2011-0062] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prolactin (PRL) is critical for alveolar proliferation and differentiation in normal mammary development and is also implicated in breast cancer. PRL influences cell proliferation and growth by altering the expression of cyclin D1. Cyclin D1 expression is directly regulated by PRL through the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 5-mediated transcriptional activation of the cyclin D1 promoter. A p21-activated serine-threonine kinase (PAK)1 has also been implicated in the regulation of cyclin D1 gene expression. We have previously demonstrated that JAK2 directly phosphorylates PAK1 and extend these data here to demonstrate that PAK1 activates the cyclin D1 promoter in response to PRL. We show that mutation of PAK1 Tyr 153, 201, and 285 (sites of JAK2 phosphorylation; PAK1 Y3F) decreases both PAK1 nuclear translocation in response to PRL and PRL-induced cyclin D1 promoter activity by 55%. Mutation of the PAK1 nuclear localization signals decreases PRL-induced cyclin D1 promoter activity by 46%. A PAK1 Y3F mutant lacking functional nuclear localization signals decreases PRL-induced cyclin D1 activity by 68%, suggesting that there is another PAK1-dependent mechanism to activate the cyclin D1 promoter. We have found that adapter protein Nck sequesters PAK1 in the cytoplasm and that coexpression of both PAK1 and Nck inhibits the amplifying effect of PRL-induced PAK1 on cyclin D1 promoter activity (95% inhibition). This inhibition is partially abolished by disruption of PAK1-Nck binding. We propose two PAK1-dependent mechanisms to activate cyclin D1 promoter activity in response to PRL: via nuclear translocation of tyrosyl-phosphorylated PAK1 and via formation of a Nck-PAK1 complex that sequesters PAK1 in the cytoplasm.
Collapse
Affiliation(s)
- Jing Tao
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606-3390, USA
| | | | | | | |
Collapse
|
7
|
Li X, Huang Y, Jiang J, Frank SJ. Synergy in ERK activation by cytokine receptors and tyrosine kinase growth factor receptors. Cell Signal 2010; 23:417-24. [PMID: 20946955 DOI: 10.1016/j.cellsig.2010.10.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 10/01/2010] [Indexed: 10/19/2022]
Abstract
Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) signal through EGF and PDGF receptors, which are important receptor tyrosine kinases (RTKs). Growth hormone (GH) and prolactin (PRL) are four helical bundle peptide hormones that signal via GHR and PRLR, members of the cytokine receptor superfamily. In this study, we examine crosstalk between signaling pathways emanating from these disparate receptor groups (RTKs and cytokine receptors). We find that GH and EGF specifically synergize for activation of ERK in murine preadipocytes. The locus of this synergy resides at the level of MEK activation, but not above this level (i.e., not at the level of EGFR, SHC, or Raf activation). Furthermore, dephosphorylation of the scaffold protein, KSR, at a critical serine residue is also synergistically promoted by GH and EGF, suggesting that GH sensitizes these cells to EGF-induced ERK activation by augmenting the actions of KSR in facilitating MEK-ERK activation. Similarly specific synergy in ERK activation is also detected in human T47D breast cancer cells by cotreatment with PRL and PDGF. This synergy also resides at the level of MEK activation. Consistent with this synergy, PRL and PDGF also synergized for c-fos-dependent transactivation of a luciferase reporter gene in T47D cells, indicating that events downstream of ERK activation reflect this signaling synergy. Important conceptual and physiological implications of these findings are discussed.
Collapse
Affiliation(s)
- Xin Li
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA
| | | | | | | |
Collapse
|
8
|
LaPensee EW, Schwemberger SJ, LaPensee CR, Bahassi EM, Afton SE, Ben-Jonathan N. Prolactin confers resistance against cisplatin in breast cancer cells by activating glutathione-S-transferase. Carcinogenesis 2009; 30:1298-304. [PMID: 19443905 DOI: 10.1093/carcin/bgp120] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Resistance to chemotherapy is a major obstacle for successful treatment of breast cancer patients. Given that prolactin (PRL) acts as an anti-apoptotic/survival factor in the breast, we postulated that it antagonizes cytotoxicity by chemotherapeutic drugs. Treatment of breast cancer cells with PRL caused variable resistance to taxol, vinblastine, doxorubicin and cisplatin. PRL prevented cisplatin-induced G(2)/M cell cycle arrest and apoptosis. In the presence of PRL, significantly less cisplatin was bound to DNA, as determined by mass spectroscopy, and little DNA damage was seen by gamma-H2AX staining. PRL dramatically increased the activity of glutathione-S-transferase (GST), which sequesters cisplatin in the cytoplasm; this increase was abrogated by Jak and mitogen-activated protein kinase inhibitors. PRL upregulated the expression of the GSTmu, but not the pi, isozyme. A GST inhibitor abrogated antagonism of cisplatin cytotoxicity by PRL. In conclusion, PRL confers resistance against cisplatin by activating a detoxification enzyme, thereby reducing drug entry into the nucleus. These data provide a rational explanation for the ineffectiveness of cisplatin in breast cancer, which is characterized by high expression of both PRL and its receptor. Suppression of PRL production or blockade of its actions should benefit patients undergoing chemotherapy by allowing for lower drug doses and expanded drug options.
Collapse
Affiliation(s)
- Elizabeth W LaPensee
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, OH 45267-0521, USA
| | | | | | | | | | | |
Collapse
|
9
|
Clevenger CV, Zheng J, Jablonski EM, Galbaugh TL, Fang F. From bench to bedside: future potential for the translation of prolactin inhibitors as breast cancer therapeutics. J Mammary Gland Biol Neoplasia 2008; 13:147-56. [PMID: 18246318 DOI: 10.1007/s10911-008-9074-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 01/04/2008] [Indexed: 11/30/2022] Open
Abstract
A role for prolactin (PRL) in the pathogenesis of breast cancer has been confirmed at the cellular level in vitro, with multiple transgenic and knockout models in vivo, and within sizable patient populations through epidemiologic analysis. It is the obvious "next step" that these findings are translated into meaningful therapies to block PRL/PRLr function in human breast cancer. Several broad categories of PRL/PRLr antagonists are discussed in their pre-clinical context, including inhibitors of endocrine PRL elaboration, mutant ligand antagonists, ligand chimeras, and inhibitors of PRL-induced signaling and transactivation. The clinical potential for GHr antagonists are also discussed. These varied approaches all have demonstrated as proof-of-principle that PRL/PRLr antagonism can inhibit the in vitro and in vivo growth of breast cancer. Further pre-clinical development is required for most, however, before translation to clinical trials in breast cancer patients can occur.
Collapse
Affiliation(s)
- Charles V Clevenger
- Diana, Princess of Wales Professor of Cancer Research, Robert H. Lurie Comprehensive Cancer Center, Department of Pathology, Northwestern University, Chicago, IL 60611, USA.
| | | | | | | | | |
Collapse
|
10
|
Tallet E, Rouet V, Jomain JB, Kelly PA, Bernichtein S, Goffin V. Rational design of competitive prolactin/growth hormone receptor antagonists. J Mammary Gland Biol Neoplasia 2008; 13:105-17. [PMID: 18219565 DOI: 10.1007/s10911-008-9066-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Accepted: 01/02/2008] [Indexed: 01/22/2023] Open
Abstract
There is increasing evidence that prolactin (PRL) and growth hormone (GH) act as growth-promoters of breast tumors. Recent arguments have accumulated to suggest that when they are locally-produced within the mammary tissue, these hormones, acting by an autocrine-paracrine mechanism may have enhanced, or even specific functions compared to endocrine PRL and GH. Classical drugs blocking pituitary hormone production (dopamine and somatostatin analogs) are ineffective on extrapituitary expression of PRL/GH genes, therefore the undesirable effects of these locally-produced hormones remain a target of interest for alternative strategies. This has encouraged the development of competitive PRL and/or GH receptor antagonists, which involve engineered variants of natural receptor ligands (PRL or GH) aimed at blocking receptor activation rather than hormone production in peripheral tissues. This article overviews the rational design of this new class of molecules, their specific molecular features (receptor specificity, biological properties, etc.) and whenever available, the data that have been obtained in cell or animal models of breast cancer.
Collapse
Affiliation(s)
- Estelle Tallet
- Inserm, U845, Centre de Recherche Croissance et signalisation, Equipe PRL, GH et tumeurs, Paris, 75015, France
| | | | | | | | | | | |
Collapse
|
11
|
Frank SJ. Mechanistic aspects of crosstalk between GH and PRL and ErbB receptor family signaling. J Mammary Gland Biol Neoplasia 2008; 13:119-29. [PMID: 18236142 DOI: 10.1007/s10911-008-9065-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 01/02/2008] [Indexed: 11/27/2022] Open
Abstract
Growth hormone (GH) and prolactin (PRL) are anterior pituitary hormones that have multiple roles in growth and metabolism. Both hormones are important in mammary development and breast cancer. The epidermal growth factor (EGF) family of peptides and the receptors that they activate (the ErbB family) are also major players in mammary biology and pathophysiology. Recent studies in signal transduction have highlighted the interplay between signaling pathways referred to as crosstalk. In this review, cell biological and signaling studies related to crosstalk between GH and PRL and the ErbB family are discussed. In particular, the role of GH- and PRL-induced phosphorylation of ErbB receptors in regulating EGF responsiveness is highlighted with attention to potential pathophysiological relevance.
Collapse
Affiliation(s)
- Stuart J Frank
- Department of Cell Biology and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294-0012, USA.
| |
Collapse
|
12
|
Abstract
Prolactin (PRL) is a 23-kDa protein hormone that binds to a single-span membrane receptor, a member of the cytokine receptor superfamily, and exerts its action via several interacting signaling pathways. PRL is a multifunctional hormone that affects multiple reproductive and metabolic functions and is also involved in tumorigenicity. In addition to being a classical pituitary hormone, PRL in humans is produced by many tissues throughout the body where it acts as a cytokine. The objective of this review is to compare and contrast multiple aspects of PRL, from structure to regulation, and from physiology to pathology in rats, mice, and humans. At each juncture, questions are raised whether, or to what extent, data from rodents are relevant to PRL homeostasis in humans. Most current knowledge on PRL has been obtained from studies with rats and, more recently, from the use of transgenic mice. Although this information is indispensable for understanding PRL in human health and disease, there is sufficient disparity in the control of the production, distribution, and physiological functions of PRL among these species to warrant careful and judicial extrapolation to humans.
Collapse
Affiliation(s)
- Nira Ben-Jonathan
- Department of Cell and Cancer Biology, University of Cincinnati, Cincinnati, Ohio 45255, USA.
| | | | | |
Collapse
|
13
|
Nouhi Z, Chughtai N, Hartley S, Cocolakis E, Lebrun JJ, Ali S. Defining the role of prolactin as an invasion suppressor hormone in breast cancer cells. Cancer Res 2006; 66:1824-32. [PMID: 16452244 DOI: 10.1158/0008-5472.can-05-2292] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Prolactin hormone (PRL) is well characterized as a terminal differentiation factor for mammary epithelial cells and as an autocrine growth/survival factor in breast cancer cells. However, this function of PRL may not fully signify its role in breast tumorigenesis. Cancer is a complex multistep progressive disease resulting not only from defects in cell growth but also in cell differentiation. Indeed, dedifferentiation of tumor cells is now recognized as a crucial event in invasion and metastasis. PRL plays a critical role in inducing/maintaining differentiation of mammary epithelial cells, suggesting that PRL signaling could serve to inhibit tumor progression. We show here that in breast cancer cells, PRL and Janus-activated kinase 2, a major kinase involved in PRL signaling, play a critical role in regulating epithelial-mesenchymal transformation (EMT), an essential process associated with tumor metastasis. Activation of the PRL receptor (PRLR), achieved by restoring PRL/JAK2 signaling in mesenchymal-like breast cancer cells, MDA-MB-231, suppressed their mesenchymal properties and reduced their invasive behavior. While blocking PRL autocrine function in epithelial-like breast cancer cells, T47D, using pharmacologic and genetic approaches induced mesenchymal-like phenotypic changes and enhanced their invasive propensity. Moreover, our results indicate that blocking PRL signaling led to activation of mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) and transforming growth factor-beta/Smad signaling pathways, two major prometastatic pathways. Furthermore, our results indicate that following PRL/JAK2 inhibition, ERK1/2 activation precedes and is required for Smad2 activation and EMT induction in breast cancer cells. Together, these results highlight PRL as a critical regulator of epithelial plasticity and implicate PRL as an invasion suppressor hormone in breast cancer.
Collapse
Affiliation(s)
- Zaynab Nouhi
- Hormones and Cancer Research Unit, Department of Medicine, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | |
Collapse
|
14
|
Langenheim JF, Chen WY. Development of a prolactin receptor-targeting fusion toxin using a prolactin antagonist and a recombinant form of Pseudomonas exotoxin A. Breast Cancer Res Treat 2005; 90:281-93. [PMID: 15830142 PMCID: PMC1398053 DOI: 10.1007/s10549-004-4816-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human prolactin (hPRL) promotes the proliferation and differentiation of mammary epithelial cells during mammary gland development and has been linked to breast tumor development. The receptor for hPRL (hPRL-R) is elevated in a majority of human breast tumors, suggesting the overexpression of hPRL-R makes cancer cells highly sensitive to the mitogenic and anti-apoptotic activity of hPRL. These findings provide the rationale for the development of hPRL-R targeting breast cancer therapeutics. Previously, an hPRL-R antagonist, G129R, was developed that competitively binds to the hPRL-R resulting in growth inhibition and the induction of apoptosis in certain types of breast cancer cells. To further increase the potency of G129R, we fused G129R to a truncated form of Pseudomonas exotoxin A (PE(40)) that lacks the cell recognition domain of the toxin but retains the domains necessary for PE(40)_ to translocate into the cytosol and inhibit protein synthesis. We postulated that the fusion of G129R with PE(40)-KDEL would (1) deliver the recombinant toxin to breast cancer cells where hPRL-R is overexpressed; (2) block hPRL signaling via its G129R moiety; and (3) inhibit protein synthesis via its PE(40)-KDEL moiety. We demonstrate that the fusion toxin can competitively bind to hPRL-Rs on T-47D human breast cancer cells and inhibit STAT5 phosphorylation induced by hPRL. In addition, we show that G129R-PE(40)-KDEL is selectively cytotoxic to breast cancer cell lines expressing the hPRL-R and that cell death is associated with the inhibition of protein synthesis and does not involve caspase mediated apoptosis.
Collapse
Affiliation(s)
- John F Langenheim
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | | |
Collapse
|
15
|
Goffin V, Bernichtein S, Kayser C, Kelly PA. Development of new prolactin analogs acting as pure prolactin receptor antagonists. Pituitary 2003; 6:89-95. [PMID: 14703018 DOI: 10.1023/b:pitu.0000004799.41035.9f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Prolactin (PRL) promotes tumor growth, as recently highlighted by the spontaneous appearance of prostate hyperplasia and mammary neoplasia in PRL transgenic mice. Increasing experimental evidence argues for the involvement of autocrine PRL in this process. Human (h)PRL receptor antagonists have been developed to counteract these undesired proliferative actions of PRL. However, all PRL receptor antagonists obtained to date exhibit partial agonism, limiting their therapeutic use as full antagonists. This is the case for the first generation antagonists (the prototype of which is G129R-hPRL) that we developed ten years ago, which display antagonistic activity in some, but not all in vitro bioassays, and fail to inhibit PRL activity in transgenic mice expressing this analog. We recently developed new human PRL antagonists devoid of agonistic properties, and therefore able to act as pure antagonists. This was demonstrated using several in vitro bioassays, including assays able to detect extremely low levels of receptor activation. These new compounds also act as pure antagonists in vivo, as demonstrated by their ability to competitively inhibit PRL-triggered signaling cascades in various target tissues (liver, mammary gland and prostate). Finally, using transgenic mice specifically expressing PRL in the prostate, which have constitutively activated signaling cascades and prostate hyperplasia, these new PRL analogs are able to completely revert PRL-activated events to basal levels. These second generation antagonists are good candidates to be used as inhibitors of the growth-promoting actions of hPRL.
Collapse
Affiliation(s)
- Vincent Goffin
- INSERM Unit 584, Hormone Targets, Faculty of Medicine, 156 rue de Vaugirard, 75730 Paris Cedex 15, France.
| | | | | | | |
Collapse
|