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Schlaeger L, Olejniczak I, Lehmann M, Schmidt CX, Astiz M, Oster H, Pilorz V. Estrogen-mediated coupling via gap junctions in the suprachiasmatic nucleus. Eur J Neurosci 2024; 59:1723-1742. [PMID: 38326974 DOI: 10.1111/ejn.16270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
The circadian clock orchestrates many physiological and behavioural rhythms in mammals with 24-h periodicity, through a hierarchical organisation, with the central clock located in the suprachiasmatic nucleus (SCN) in the hypothalamus. The circuits of the SCN generate circadian rhythms with precision, relying on intrinsic coupling mechanisms, for example, neurotransmitters like arginine vasopressin (AVP), vasoactive intestinal peptide (VIP), neuronal gamma-aminobutyric acid (GABA) signalling and astrocytes connected by gap junctions composed of connexins (Cx). In female rodents, the presence of estrogen receptors (ERs) in the dorsal SCN suggests an influence of estrogen (E2) on the circuit timekeeping that could regulate circadian rhythm and coupling. To investigate this, we used SCN explants together with hypothalamic neurons and astrocytes. First, we showed that E2 stabilised the circadian amplitude in the SCN when rAVPs (receptor-associated vasopressin peptides) were inhibited. However, the phase delay induced by VIPAC2 (VIP receptors) inhibition remained unaffected by E2. We then showed that E2 exerted its effects in the SCN via ERβ (estrogen receptor beta), resulting in increased expression of Cx36 and Cx43. Notably, specific inhibition of both connexins resulted in a significant reduction in circadian amplitude within the SCN. Remarkably, E2 restored the period with inhibited Cx36 but not with Cx43 inhibition. This implies that the network between astrocytes and neurons, responsible for coupling in the SCN, can be reinforced through E2. In conclusion, these findings provide new insights into how E2 regulates circadian rhythms ex vivo in an ERβ-dependent manner, underscoring its crucial role in fortifying the SCN's rhythm.
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Affiliation(s)
- Lina Schlaeger
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Iwona Olejniczak
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Marianne Lehmann
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Cosima Xenia Schmidt
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Mariana Astiz
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Henrik Oster
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
| | - Violetta Pilorz
- Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany
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2
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Cho H, Yun A, Kim J, Park E, Jung JW, Chung S, Son GH. Functional Characterization of Circadian Nuclear Receptors REV-ERBα and REV-ERBβ in Human Osteosarcoma Cell Cultures. Int J Mol Sci 2024; 25:770. [PMID: 38255844 PMCID: PMC10815705 DOI: 10.3390/ijms25020770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
REV-ERBα and its paralog, REV-ERBβ, encoded by NR1D1 and NR1D2 genes, are key nuclear receptors that link the circadian timing system and metabolic homeostasis. Since heme is an endogenous ligand, REV-ERBs have been considered key components of the circadian molecular clock and can be pharmacologically targeted to treat various circadian rhythm-related diseases, such as cardiometabolic, inflammatory, and neuropsychiatric diseases, as well as cancer. REV-ERBs are believed to be functionally redundant and compensatory, although they often affect the expression of gene subsets in an isoform-specific manner. Therefore, this study aimed to identify the redundant and distinct roles of each isoform in controlling its target genes by comparing the transcriptome profiles of a panel of mutant U2OS human osteosarcoma cells in which either NR1D1 or NR1D2 was ablated. Indeed, our transcriptomic analyses revealed that most REV-ERB-regulated genes are controlled by redundant or even additive actions. However, the RNA expression profiles of each single mutant cell line also provide strong evidence for isoform-dependent actions. For example, REV-ERBα is more responsible for regulating the NF-κΒ signaling pathway, whereas a group of extracellular matrix components requires REV-ERBβ to maintain their expression. We found that REV-ERBs have isoform-selective functions in the regulation of certain circadian output pathways despite their overlapping roles in the circadian molecular clock. Thus, the development of isoform-selective REV-ERB modulators can help treat metabolic disturbances and certain types of cancer.
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Affiliation(s)
- Hana Cho
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Republic of Korea; (H.C.); (J.K.); (E.P.)
| | - Ahee Yun
- Department of Brain and Cognitive Sciences, Scranton College, Ewha Womans University, Seoul 03760, Republic of Korea;
| | - Joohee Kim
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Republic of Korea; (H.C.); (J.K.); (E.P.)
| | - Eunjeong Park
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Republic of Korea; (H.C.); (J.K.); (E.P.)
| | - Jong-Wha Jung
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Sooyoung Chung
- Department of Brain and Cognitive Sciences, Scranton College, Ewha Womans University, Seoul 03760, Republic of Korea;
| | - Gi Hoon Son
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Republic of Korea; (H.C.); (J.K.); (E.P.)
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3
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Chen Y, Li J, Li S, Cheng Y, Fu X, Li J, Zhu L. Uncovering the Novel Role of NR1D1 in Regulating BNIP3-Mediated Mitophagy in Ulcerative Colitis. Int J Mol Sci 2023; 24:14222. [PMID: 37762536 PMCID: PMC10531686 DOI: 10.3390/ijms241814222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/07/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Ulcerative colitis (UC) is a chronic, incurable condition characterized by mucosal inflammation and intestinal epithelial cell (IEC) damage. The circadian clock gene NR1D1, implicated in UC and the critical mitophagy process for epithelial repair, needs further exploration regarding its role in mitophagy regulation in UC. METHODS We created a jet lag mouse model and induced colitis with dextran sulfate sodium (DSS), investigating NR1D1's role. Intestinal-specific Nr1d1 knockout mice were also generated. RNA sequencing, chromatin immunoprecipitation (ChIP), and dual-luciferase reporter assays helped ascertain NR1D1's regulatory effect on BNIP3 expression. The mitochondrial state in IECs was assessed through transmission electron microscopy, while confocal microscopy evaluated mitophagy-associated protein expression in colon tissue and CCD841 cells. Cell apoptosis and reactive oxygen species (ROS) were measured via flow cytometry. RESULTS We observed reduced NR1D1 expression in the IECs of UC patients, accentuated under jet lag and DSS exposure in mice. NR1D1 ablation led to disrupted immune homeostasis and declined mitophagy in IECs. NR1D1, usually a transcriptional repressor, was a positive regulator of BNIP3 expression, leading to impaired mitophagy, cellular inflammation, and apoptosis. Administering the NR1D1 agonist SR9009 ameliorated colitis symptoms, primarily by rectifying defective mitophagy. CONCLUSIONS Our results suggest that NR1D1 bridges the circadian clock and UC, controlling BNIP3-mediated mitophagy and representing a potential therapeutic target. Its agonist, SR9009, shows promise in UC symptom alleviation.
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Affiliation(s)
| | | | | | | | | | | | - Liangru Zhu
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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4
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Hashikawa KI, Tsuruta A, Yamakawa W, Yasukochi S, Koyanagi S, Ohdo S. Senescence-induced alteration of circadian phagocytic activity of retinal pigment epithelium cell line ARPE-19. Biochem Biophys Res Commun 2023; 658:88-96. [PMID: 37027909 DOI: 10.1016/j.bbrc.2023.03.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 03/29/2023] [Indexed: 03/31/2023]
Abstract
Renewal of retinal photoreceptor outer segments is conducted through daily shedding of distal photoreceptor outer segment tips and subsequent their phagocytosis by the adjacent retinal pigment epithelium (RPE) monolayer. Dysregulation of the diurnal clearance of photoreceptor outer segment tips has been implicated in age-related retinal degeneration, but it remains to be clarified how the circadian phagocytic activity of RPE cells is modulated by senescence. In this study, we used the human RPE cell line ARPE-19 to investigate whether hydrogen peroxide (H2O2)-induced senescence in ARPE-19 cells alters the circadian rhythm of their phagocytic activity. After synchronization of the cellular circadian clock by dexamethasone treatment, the phagocytic activity of normal ARPE-19 cells exhibited significant 24-h oscillation, but this oscillation was modulated by senescence. The phagocytic activity of senescent ARPE-19 cells increased constantly throughout the 24-h period, which still exhibited blunted circadian oscillation, accompanied by an alteration in the rhythmic expression of circadian clock genes and clock-controlled phagocytosis-related genes. The expression levels of REV-ERBα, a molecular component of the circadian clock, were constitutively increased in senescent ARPE-19 cells. Furthermore, pharmacological activation of REV-ERBα by its agonist SR9009 enhanced the phagocytic activity of normal ARPE-19 cells and increased the expression of clock-controlled phagocytosis-related genes. Our present findings extend to understand the role of circadian clock in the alteration of phagocytic activity in RPE during aging. Constitutive enhancement of phagocytic activity of senescent RPE may contribute to age-related retinal degeneration.
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Affiliation(s)
- Ken-Ichi Hashikawa
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Akito Tsuruta
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan; Department of Glocal Healthcare Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Wakaba Yamakawa
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Sai Yasukochi
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Satoru Koyanagi
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan; Department of Glocal Healthcare Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
| | - Shigehiro Ohdo
- Department of Pharmaceutics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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5
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Ramos S, Ademolue TW, Jentho E, Wu Q, Guerra J, Martins R, Pires G, Weis S, Carlos AR, Mahú I, Seixas E, Duarte D, Rajas F, Cardoso S, Sousa AGG, Lilue J, Paixão T, Mithieux G, Nogueira F, Soares MP. A hypometabolic defense strategy against malaria. Cell Metab 2022; 34:1183-1200.e12. [PMID: 35841892 DOI: 10.1016/j.cmet.2022.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 04/15/2022] [Accepted: 06/20/2022] [Indexed: 12/26/2022]
Abstract
Hypoglycemia is a clinical hallmark of severe malaria, the often-lethal outcome of Plasmodium falciparum infection. Here, we report that malaria-associated hypoglycemia emerges from a non-canonical resistance mechanism, whereby the infected host reduces glycemia to starve Plasmodium. This hypometabolic response is elicited by labile heme, a byproduct of hemolysis that induces illness-induced anorexia and represses hepatic glucose production. While transient repression of hepatic glucose production prevents unfettered immune-mediated inflammation, organ damage, and anemia, when sustained over time it leads to hypoglycemia, compromising host energy expenditure and adaptive thermoregulation. The latter arrests the development of asexual stages of Plasmodium via a mechanism associated with parasite mitochondrial dysfunction. In response, Plasmodium activates a transcriptional program associated with the reduction of virulence and sexual differentiation toward the generation of transmissible gametocytes. In conclusion, malaria-associated hypoglycemia represents a trade-off of a hypometabolic-based defense strategy that balances parasite virulence versus transmission.
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Affiliation(s)
- Susana Ramos
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Elisa Jentho
- Instituto Gulbenkian de Ciência, Oeiras, Portugal; Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany
| | - Qian Wu
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Joel Guerra
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany
| | - Rui Martins
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Gil Pires
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Sebastian Weis
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany; Institute for Infectious Disease and Infection Control, University Hospital Jena, Jena, Germany; Center for Sepsis Control and Care, Jena University, Jena, Germany; Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), 07745 Jena, Germany
| | | | - Inês Mahú
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Elsa Seixas
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Denise Duarte
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisboa, Portugal
| | | | | | | | | | - Tiago Paixão
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Fátima Nogueira
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisboa, Portugal
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6
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Costa V, De Fine M, Carina V, Conigliaro A, Raimondi L, De Luca A, Bellavia D, Salamanna F, Alessandro R, Pignatti G, Fini M, Giavaresi G. How miR-31-5p and miR-33a-5p Regulates SP1/CX43 Expression in Osteoarthritis Disease: Preliminary Insights. Int J Mol Sci 2021; 22:2471. [PMID: 33671114 PMCID: PMC7957523 DOI: 10.3390/ijms22052471] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 12/24/2022] Open
Abstract
Osteoarthritis (OA) is a degenerative bone disease that involved micro and macro-environment of joints. To date, there are no radical curative treatments for OA and novel therapies are mandatory. Recent evidence suggests the role of miRNAs in OA progression. In our previous studies, we demonstrated the role of miR-31-5p and miR-33a families in different bone regeneration signaling. Here, we investigated the role of miR-31-5p and miR-33a-5p in OA progression. A different expression of miR-31-5p and miR-33a-5p into osteoblasts and chondrocytes isolated from joint tissues of OA patients classified in based on different Kellgren and Lawrence (KL) grading was highlighted; and through a bioinformatic approach the common miRNAs target Specificity proteins (Sp1) were identified. Sp1 regulates the expression of gap junction protein Connexin43 (Cx43), which in OA drives the modification of i) osteoblasts and chondrocytes genes expression, ii) joint inflammation cytokines releases and iii) cell functions. Concerning this, thanks to gain and loss of function studies, the possible role of Sp1 as a modulator of CX43 expression through miR-31-5p and miR-33a-5p action was also evaluated. Finally, we hypothesize that both miRNAs cooperate to modulate the expression of SP1 in osteoblasts and chondrocytes and interfering, consequently, with CX43 expression, and they might be further investigated as new possible biomarkers for OA.
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Affiliation(s)
- Viviana Costa
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Marcello De Fine
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (M.D.F.); (G.P.)
| | - Valeria Carina
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Alice Conigliaro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Section of Biology and Genetics, University of Palermo, 90133 Palermo, Italy; (A.C.); (R.A.)
| | - Lavinia Raimondi
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Angela De Luca
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Daniele Bellavia
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Francesca Salamanna
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Riccardo Alessandro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Section of Biology and Genetics, University of Palermo, 90133 Palermo, Italy; (A.C.); (R.A.)
- Istituto per la Ricerca e l’Innovazione Biomedica (IRIB), 90133 Palermo, Italy
| | - Giovanni Pignatti
- IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (M.D.F.); (G.P.)
| | - Milena Fini
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
| | - Gianluca Giavaresi
- SC Scienze e Tecnologie Chirurgiche-SS Piattaforma Scienze Omiche per Ortopedia Personalizzata, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy; (V.C.); (L.R.); (A.D.L.); (D.B.); (F.S.); (M.F.); (G.G.)
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7
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Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
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Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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8
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Burgermeister E, Battaglin F, Eladly F, Wu W, Herweck F, Schulte N, Betge J, Härtel N, Kather JN, Weis CA, Gaiser T, Marx A, Weiss C, Hofheinz R, Miller IS, Loupakis F, Lenz HJ, Byrne AT, Ebert MP. Aryl hydrocarbon receptor nuclear translocator-like (ARNTL/BMAL1) is associated with bevacizumab resistance in colorectal cancer via regulation of vascular endothelial growth factor A. EBioMedicine 2019; 45:139-154. [PMID: 31300350 PMCID: PMC6642438 DOI: 10.1016/j.ebiom.2019.07.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The identification of new biomarkers and the development of novel, targetable contexts of vulnerability are of urgent clinical need in drug-resistant metastatic colorectal cancer (mCRC). Aryl-Hydrocarbon-Receptor-Nuclear-Translocator-Like (ARNTL/BMAL1) is a circadian clock-regulated transcription factor promoting expression of genes involved in angiogenesis and tumour progression. We hypothesised that BMAL1 increases expression of the vascular endothelial growth factor A VEGFA gene and, thereby, confers resistance to anti-angiogenic therapy with bevacizumab (Beva), a clinically used antibody for neutralization of VEGFA. METHODS PCR and immunohistochemistry were employed to assess BMAL1 expression in mice (C57BL/6 J Apcmin/+; BALB/c nu/nu xenografts) and CRC patients under combination chemotherapy with Beva. BMAL1 single nucleotide gene polymorphisms (SNPs) were analysed by DNA-microarray in clinical samples. BMAL1 functions were studied in human CRC cell lines using colorimetric growth, DNA-binding and reporter assays. FINDINGS In murine CRCs, high BMAL1 expression correlated with poor preclinical response to Beva treatment. In CRC patients' tumours (n = 74), high BMAL1 expression was associated with clinical non-response to combination chemotherapy with Beva (*p = .0061) and reduced progression-free survival (PFS) [*p = .0223, Hazard Ratio (HR) = 1.69]. BMAL1 SNPs also correlated with shorter PFS (rs7396943, rs7938307, rs2279287) and overall survival (OS) [rs11022780, *p = .014, HR = 1.61]. Mechanistically, Nuclear-Receptor-Subfamily-1-Group-D-Member-1 (NR1D1/REVERBA) bound a - 672 bp Retinoic-Acid-Receptor-Related-Orphan-Receptor-Alpha-responsive-element (RORE) adjacent to a BMAL1 DNA-binding motif (E-box) in the VEGFA gene promoter, resulting in increased VEGFA synthesis and proliferation of human CRC cell lines. INTERPRETATION BMAL1 was associated with Beva resistance in CRC. Inhibition of REVERBA-BMAL1 signalling may prevent resistance to anti-angiogenic therapy. FUND: This work was in part supported by the European Commission Seventh Framework Programme (Contract No. 278981 [ANGIOPREDICT]).
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Affiliation(s)
- Elke Burgermeister
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
| | - Francesca Battaglin
- Division of Medical Oncology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, CA, United States; Unit of Medical Oncology 1, Clinical and Experimental Oncology Department, Veneto Institute of Oncology IOV - IRCCS, Padua, Italy
| | - Fagr Eladly
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Wen Wu
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Frank Herweck
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Nadine Schulte
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Johannes Betge
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Nicolai Härtel
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Jakob N Kather
- Division of Gastroenterology, Hepatology and Hepatobiliary Oncology, University Hospital RWTH Aachen, Aachen, Germany
| | - Cleo-Aron Weis
- Institute of Pathology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Timo Gaiser
- Institute of Pathology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Alexander Marx
- Institute of Pathology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Christel Weiss
- Department of Medical Statistics, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ralf Hofheinz
- Department of Medicine III, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ian S Miller
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Fotios Loupakis
- Unit of Medical Oncology 1, Clinical and Experimental Oncology Department, Veneto Institute of Oncology IOV - IRCCS, Padua, Italy
| | - Heinz-Josef Lenz
- Division of Medical Oncology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, CA, United States
| | - Annette T Byrne
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland; UCD School of Biomolecular and Biomedical Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Matthias P Ebert
- Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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9
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Ali AAH, Stahr A, Ingenwerth M, Theis M, Steinhäuser C, von Gall C. Connexin30 and Connexin43 show a time-of-day dependent expression in the mouse suprachiasmatic nucleus and modulate rhythmic locomotor activity in the context of chronodisruption. Cell Commun Signal 2019; 17:61. [PMID: 31186021 PMCID: PMC6560876 DOI: 10.1186/s12964-019-0370-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/14/2019] [Indexed: 11/15/2022] Open
Abstract
Background The astroglial connexins Cx30 and Cx43 contribute to many important CNS functions including cognitive behaviour, motoric capacity and regulation of the sleep-wake cycle. The sleep wake cycle, is controlled by the circadian system. The central circadian rhythm generator resides in the suprachiasmatic nucleus (SCN). SCN neurons are tightly coupled in order to generate a coherent circadian rhythm. The SCN receives excitatory glutamatergic input from the retina which mediates entrainment of the circadian system to the environmental light-dark cycle. Connexins play an important role in electric coupling of SCN neurons and astrocytic-neuronal signalling that regulates rhythmic SCN neuronal activity. However, little is known about the regulation of Cx30 and Cx43 expression in the SCN, and the role of these connexins in light entrainment of the circadian system and in circadian rhythm generation. Methods We analysed time-of-day dependent as well as circadian expression of Cx30 and Cx43 mRNA and protein in the mouse SCN by means of qPCR and immunohistochemistry. Moreover, we analysed rhythmic spontaneous locomotor activity in mice with a targeted deletion of Cx30 and astrocyte specific deletion of Cx43 (DKO) in different light regimes by means of on-cage infrared detectors. Results Fluctuation of Cx30 protein expression is strongly dependent on the light-dark cycle whereas fluctuation of Cx43 protein expression persisted in constant darkness. DKO mice entrained to the light-dark cycle. However, re-entrainment after a phase delay was slightly impaired in DKO mice. Surprisingly, DKO mice were more resilient to chronodisruption. Conclusion Circadian fluctuation of Cx30 and Cx43 protein expression in the SCN is differently regulated. Cx30 and astroglial Cx43 play a role in rhythm stability and re-entrainment under challenging conditions. Electronic supplementary material The online version of this article (10.1186/s12964-019-0370-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amira A H Ali
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany
| | - Anna Stahr
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany
| | - Marc Ingenwerth
- Institute of Pathology, Medical Faculty, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
| | - Martin Theis
- Institute of Cellular Neurosciences, Medical Faculty, University Bonn, Sigmund Freud Str. 25, 53105, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University Bonn, Sigmund Freud Str. 25, 53105, Bonn, Germany
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany.
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10
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McLeod AB, Stice JP, Wardell SE, Alley HM, Chang CY, McDonnell DP. Validation of histone deacetylase 3 as a therapeutic target in castration-resistant prostate cancer. Prostate 2018; 78:266-277. [PMID: 29243324 DOI: 10.1002/pros.23467] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND Whereas the androgen receptor (AR) signaling axis remains a therapeutic target in castration-resistant prostate cancer (CRPC), the emergence of AR mutations and splice variants as mechanisms underlying resistance to contemporary inhibitors of this pathway highlights the need for new therapeutic approaches to target this disease. Of significance in this regard is the considerable preclinical data, indicating that histone deacetylase (HDAC) inhibitors may have utility in the treatment of CRPC. However, the results of clinical studies using HDAC inhibitors (directed against HDAC1, 2, 3, and 8) in CRPC are equivocal, a result that some have attributed to their ability to induce an epithelial to mesenchymal transition (EMT) and neuroendocrine differentiation. We posited that it might be possible to uncouple the beneficial effects of HDAC inhibitors on AR signaling from their undesired activities by targeting specific HDACs as opposed to using the pan-inhibitor strategy that has been employed to date. METHODS The relative abilities of pan- and selective-Class I HDAC inhibitors to attenuate AR-mediated target gene expression and proliferation were assessed in several prostate cancer cell lines. Small interfering RNA (siRNA)-mediated knockdown approaches were used to confirm the importance of of HDAC 1, 2, and 3 expression in these processes. Further, the ability of each HDAC inhibitor to induce the expression of EMT markers (RNA and protein) and EMT-like phenotype(s) (migration) were also assessed. The anti-tumor efficacy of a HDAC3-selective inhibitor, RGFP966, was compared to the pan-HDAC inhibitor Suberoylanilide Hydroxamic Acid (SAHA) in the 22Rv1 xenograft model. RESULTS Using genetic and pharmacological approaches we demonstrated that a useful inhibition of AR transcriptional activity, absent the induction of EMT, could be achieved by specifically inhibiting HDAC3. Significantly, we also determined that HDAC3 inhibitors blocked the activity of the constitutively active AR V7-splice variant and inhibited the growth of xenograft tumors expressing this protein. CONCLUSIONS Our studies provide strong rationale for the near-term development of specific HDAC3 inhibitors for the treatment of CRPC.
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Affiliation(s)
- Abigail B McLeod
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - James P Stice
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - Suzanne E Wardell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - Holly M Alley
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - Ching-Yi Chang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - Donald P McDonnell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
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Sengiku A, Ueda M, Kono J, Sano T, Nishikawa N, Kunisue S, Tsujihana K, Liou LS, Kanematsu A, Shimba S, Doi M, Okamura H, Ogawa O, Negoro H. Circadian coordination of ATP release in the urothelium via connexin43 hemichannels. Sci Rep 2018; 8:1996. [PMID: 29386573 PMCID: PMC5792455 DOI: 10.1038/s41598-018-20379-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/17/2018] [Indexed: 11/17/2022] Open
Abstract
Day-night changes in the storage capacity of the urinary bladder are indispensable for sound sleep. Connexin 43 (Cx43), a major gap junction protein, forms hemichannels as a pathway of ATP in other cell types, and the urinary bladder utilizes ATP as a mechanotransduction signals to modulate its capacity. Here, we demonstrate that the circadian clock of the urothelium regulates diurnal ATP release through Cx43 hemichannels. Cx43 was expressed in human and mouse urothelium, and clock genes oscillated in the mouse urothelium accompanied by daily cycles in the expression of Cx43 and extracellular ATP release into the bladder lumen. Equivalent chronological changes in Cx43 and ATP were observed in immortalized human urothelial cells, but these diurnal changes were lost in both arrhythmic Bmal1-knockout mice and in BMAL1-knockdown urothelial cells. ATP release was increased by Cx43 overexpression and was decreased in Cx43 knockdown or in the presence of a selective Cx43 hemichannel blocker, which indicated that Cx43 hemichannels are considered part of the components regulating ATP release in the urothelium. Thus, a functional circadian rhythm exists in the urothelium, and coordinates Cx43 expression and function as hemichannels that provide a direct pathway of ATP release for mechanotransduction and signalling in the urothelium.
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Affiliation(s)
- Atsushi Sengiku
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Masakatsu Ueda
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Jin Kono
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Takeshi Sano
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Nobuyuki Nishikawa
- Department of Urology, Japanese Red Cross Otsu Hospital, Shiga, 520-8511, Japan
| | - Sumihiro Kunisue
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Kojiro Tsujihana
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
- Department of Dermatology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Louis S Liou
- Department of Urology, Cambridge Health Alliance, Cambridge, MA, 02139, USA
| | - Akihiro Kanematsu
- Department of Urology, Hyogo College of Medicine, Hyogo, 663-8501, Japan
| | - Shigeki Shimba
- Department of Health Science, School of Pharmacy, Nihon University, Chiba, 245-8555, Japan
| | - Masao Doi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Hitoshi Okamura
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Osamu Ogawa
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Hiromitsu Negoro
- Department of Urology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.
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Chandra V, Bhagyaraj E, Nanduri R, Ahuja N, Gupta P. NR1D1 ameliorates Mycobacterium tuberculosis clearance through regulation of autophagy. Autophagy 2015; 11:1987-1997. [PMID: 26390081 PMCID: PMC4824569 DOI: 10.1080/15548627.2015.1091140] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 08/19/2015] [Accepted: 09/01/2015] [Indexed: 01/07/2023] Open
Abstract
NR1D1 (nuclear receptor subfamily 1, group D, member 1), an adopted orphan nuclear receptor, is widely known to orchestrate the expression of genes involved in various biological processes such as adipogenesis, skeletal muscle differentiation, and lipid and glucose metabolism. Emerging evidence suggests that various members of the nuclear receptor superfamily perform a decisive role in the modulation of autophagy. Recently, NR1D1 has been implicated in augmenting the antimycobacterial properties of macrophages and providing protection against Mycobacterium tuberculosis infection by downregulating the expression of the IL10 gene in human macrophages. This antiinfective property of NR1D1 suggests the need for an improved understanding of its role in other host-associated antimycobacterial pathways. The results presented here demonstrate that in human macrophages either ectopic expression of NR1D1 or treatment with its agonist, GSK4112, enhanced the number of acidic vacuoles as well as the level of MAP1LC3-II, a signature molecule for determination of autophagy progression, in a concentration- and time-dependent manner. Conversely, a decrease in NR1D1 in knockdown cells resulted in the reduced expression of lysosomal-associated membrane protein 1, LAMP1, commensurate with a decrease in the level of transcription factor EB, TFEB. This is indicative of that NR1D1 may have a regulatory role in lysosome biogenesis. NR1D1 being a repressor, its positive regulation on LAMP1 and TFEB is suggestive of an indirect byzantine mechanism of action. Its role in the modulation of autophagy and lysosome biogenesis together with its ability to repress IL10 gene expression supports the theory that NR1D1 has a pivotal antimycobacterial function in human macrophages.
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Affiliation(s)
- Vemika Chandra
- CSIR- Institute of Microbial Technology; Chandigarh, India
| | - Ella Bhagyaraj
- CSIR- Institute of Microbial Technology; Chandigarh, India
| | | | - Nancy Ahuja
- CSIR- Institute of Microbial Technology; Chandigarh, India
| | - Pawan Gupta
- CSIR- Institute of Microbial Technology; Chandigarh, India
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Tarzemany R, Jiang G, Larjava H, Häkkinen L. Expression and function of connexin 43 in human gingival wound healing and fibroblasts. PLoS One 2015; 10:e0115524. [PMID: 25584940 PMCID: PMC4293150 DOI: 10.1371/journal.pone.0115524] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 11/25/2014] [Indexed: 11/18/2022] Open
Abstract
Connexins (C×s) are a family of transmembrane proteins that form hemichannels and gap junctions (GJs) on the cell membranes, and transfer small signaling molecules between the cytoplasm and extracellular space and between connecting cells, respectively. Among C×s, suppressing C×43 expression or function promotes skin wound closure and granulation tissue formation, and may alleviate scarring, but the mechanisms are not well understood. Oral mucosal gingiva is characterized by faster wound closure and scarless wound healing outcome as compared to skin wounds. Therefore, we hypothesized that C×43 function is down regulated during human gingival wound healing, which in fibroblasts promotes expression of genes conducive for fast and scarless wound healing. Cultured gingival fibroblasts expressed C×43 as their major connexin. Immunostaining of unwounded human gingiva showed that C×43 was abundantly present in the epithelium, and in connective tissue formed large C×43 plaques in fibroblasts. At the early stages of wound healing, C×43 was strongly down regulated in wound epithelial cells and fibroblasts, returning to the level of normal tissue by day 60 post-wounding. Blocking of C×43 function by C×43 mimetic peptide Gap27 suppressed GJ-mediated dye transfer, promoted migration, and caused significant changes in the expression of wound healing-associated genes in gingival fibroblasts. In particular, out of 54 genes analyzed, several MMPs and TGF-β1, involved in regulation of inflammation and extracellular matrix (ECM) turnover, and VEGF-A, involved in angiogenesis, were significantly upregulated while pro-fibrotic ECM molecules, including Collagen type I, and cell contractility-related molecules were significantly down regulated. These responses involved MAPK, GSK3α/β and TGF-β signaling pathways, and AP1 and SP1 transcription factors. Thus, suppressed function of C×43 in fibroblasts promotes their migration, and regulates expression of wound healing-associated genes via AP1, SP1, MAPK, GSK3α/β and TGF-β signaling pathways, and may promote fast and scarless wound healing in human gingiva.
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Affiliation(s)
- Rana Tarzemany
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Guoqiao Jiang
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Hannu Larjava
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Lari Häkkinen
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
- * E-mail:
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Abstract
The nuclear receptors REV-ERB (consisting of REV-ERBα and REV-ERBβ) and retinoic acid receptor-related orphan receptors (RORs; consisting of RORα, RORβ and RORγ) are involved in many physiological processes, including regulation of metabolism, development and immunity as well as the circadian rhythm. The recent characterization of endogenous ligands for these former orphan nuclear receptors has stimulated the development of synthetic ligands and opened up the possibility of targeting these receptors to treat several diseases, including diabetes, atherosclerosis, autoimmunity and cancer. This Review focuses on the latest developments in ROR and REV-ERB pharmacology indicating that these nuclear receptors are druggable targets and that ligands targeting these receptors may be useful in the treatment of several disorders.
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Safe S, Jin UH, Hedrick E, Reeder A, Lee SO. Minireview: role of orphan nuclear receptors in cancer and potential as drug targets. Mol Endocrinol 2013; 28:157-72. [PMID: 24295738 DOI: 10.1210/me.2013-1291] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The nuclear orphan receptors for which endogenous ligands have not been identified include nuclear receptor (NR)0B1 (adrenal hypoplasia congenita critical region on chromosome X gene), NR0B2 (small heterodimer partner), NR1D1/2 (Rev-Erbα/β), NR2C1 (testicular receptor 2), NR2C2 (testicular receptor 4), NR2E1 (tailless), NR2E3 (photoreceptor-specific NR [PNR]), NR2F1 chicken ovalbumin upstream promoter transcription factor 1 (COUP-TFI), NR2F2 (COUP-TFII), NR2F6 (v-erbA-related protein), NR4A1 (Nur77), NR4A2 (Nurr1), NR4A3 (Nor1), and NR6A1 (GCNF). These receptors play essential roles in development, cellular homeostasis, and disease including cancer where over- or underexpression of some receptors has prognostic significance for patient survival. Results of receptor knockdown or overexpression in vivo and in cancer cell lines demonstrate that orphan receptors exhibit tumor-specific pro-oncogenic or tumor suppressor-like activity. For example, COUP-TFII expression is both a positive (ovarian) and negative (prostate and breast) prognostic factor for cancer patients; in contrast, the prognostic activity of adrenal hypoplasia congenita critical region on chromosome X gene for the same tumors is the inverse of COUP-TFII. Functional studies show that Nur77 is tumor suppressor like in acute leukemia, whereas silencing Nur77 in pancreatic, colon, lung, lymphoma, melanoma, cervical, ovarian, gastric, and some breast cancer cell lines induces one or more of several responses including growth inhibition and decreased survival, migration, and invasion. Although endogenous ligands for the orphan receptors have not been identified, there is increasing evidence that different structural classes of compounds activate, inactivate, and directly bind several orphan receptors. Thus, the screening and development of selective orphan receptor modulators will have important clinical applications as novel mechanism-based agents for treating cancer patients overexpressing one or more orphan receptors and also for combined drug therapies.
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Affiliation(s)
- Stephen Safe
- Department of Veterinary Physiology and Pharmacology (S.S., E.H., A.R.), Texas A&M University, College Station, Texas 77808; and Institute of Biosciences and Technology (S.S., U.-H.J., S.-O.L.), Texas A&M Health Science Center, Houston, Texas 77030
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