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Wei S, Zhang M, Li Y, Yang W, Zhang C, Liu F, Chen S, Ban B, He D. Identification and functional analysis of first heterozygous frameshift mutation in the GHRH gene in a Chinese boy with isolated growth hormone deficiency. Gene 2024; 907:148283. [PMID: 38354915 DOI: 10.1016/j.gene.2024.148283] [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: 10/24/2023] [Revised: 01/26/2024] [Accepted: 02/09/2024] [Indexed: 02/16/2024]
Abstract
BACKGROUND Isolated growth hormone deficiency (IGHD) is a rare genetically heterogeneous disorder caused primarily by mutations in GH1 and GH releasing hormone receptor (GHRHR). The aim of this study was to identify the molecular etiology of a Chinese boy with IGHD. METHODS Whole-exome sequencing, sanger sequencing and bioinformatic analysis were performed to screen for candidate mutations. The impacts of candidate mutation on gene expression, intracellular localization and protein function were further evaluated by in vitro assays. RESULTS A novel heterozygous frameshift mutation in the GHRH gene (c.91dupC, p.R31Pfs*98) was identified in a Chinese boy clinically diagnosed as having IGHD. The mutation was absent in multiple public databases, and considered as deleterious using in silico prediction, conservative analysis and three-dimensional homology modeling. Furthermore, mRNA and protein expression levels of mutant GHRH were significantly increased than wild-type GHRH (p < 0.05). Moreover, mutant GHRH showed an aberrant accumulation within the cytoplasm, and obviously reduced ability to stimulate GH secretion and cAMP accumulation in human GHRHR-expressing pituitary GH3 cells compared to wild-type GHRH (p < 0.05). CONCLUSION Our study discovered the first loss-of function mutation of GHRH in a Chinese boy with IGHD and provided new insights on IGHD pathogenesis caused by GHRH haploinsufficiency.
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Affiliation(s)
- Shuoshuo Wei
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China
| | - Mei Zhang
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Chinese Research Center for Behavior Medicine in Growth and Development, Jining, PR China
| | - Yanying Li
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Chinese Research Center for Behavior Medicine in Growth and Development, Jining, PR China
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, PR China
| | - Chuanpeng Zhang
- Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China
| | - Fupeng Liu
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China
| | - Shuxiong Chen
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China
| | - Bo Ban
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China; Chinese Research Center for Behavior Medicine in Growth and Development, Jining, PR China.
| | - Dongye He
- Department of Endocrinology, Genetics and Metabolism, Affiliated Hospital of Jining Medical University, Jining, PR China; Medical Research Center, Affiliated Hospital of Jining Medical University, Jining, PR China.
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Gesmundo I, Granato G, Fuentes-Fayos AC, Alvarez CV, Dieguez C, Zatelli MC, Congiusta N, Banfi D, Prencipe N, Leone S, Brunetti L, Castaño JP, Luque RM, Cai R, Sha W, Ghigo E, Schally AV, Granata R. Antagonists of Growth Hormone-Releasing Hormone Inhibit the Growth of Pituitary Adenoma Cells by Hampering Oncogenic Pathways and Promoting Apoptotic Signaling. Cancers (Basel) 2021; 13:cancers13163950. [PMID: 34439107 PMCID: PMC8393969 DOI: 10.3390/cancers13163950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/26/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Many studies have demonstrated that the antagonists of growth hormone-releasing hormone (GHRH) exert inhibitory activities in a variety of experimental cancers; however, their potential antitumor role in pituitary adenomas (PAs) remains largely unknown. Here, we show that GHRH antagonists of Miami (MIA) class, MIA-602 and MIA-690, are able to reduce the growth and promote cell death in hormone-secreting PA cell lines, through the inhibition of mechanisms implicated in tumorigenesis and cancer progression. MIA-602 and MIA-690 also decreased the viability of tumor cells derived from human pituitary tumors. Overall, these findings suggest that GHRH antagonists may represent new therapeutic tools for the treatment of PAs, both alone or in combination with standard pharmacological treatments. Abstract Pituitary adenomas (PAs) are intracranial tumors, often associated with excessive hormonal secretion and severe comorbidities. Some patients are resistant to medical therapies; therefore, novel treatment options are needed. Antagonists of growth hormone-releasing hormone (GHRH) exert potent anticancer effects, and early GHRH antagonists were found to inhibit GHRH-induced secretion of pituitary GH in vitro and in vivo. However, the antitumor role of GHRH antagonists in PAs is largely unknown. Here, we show that the GHRH antagonists of MIAMI class, MIA-602 and MIA-690, inhibited cell viability and growth and promoted apoptosis in GH/prolactin-secreting GH3 PA cells transfected with human GHRH receptor (GH3-GHRHR), and in adrenocorticotropic hormone ACTH-secreting AtT20 PA cells. GHRH antagonists also reduced the expression of proteins involved in tumorigenesis and cancer progression, upregulated proapoptotic molecules, and lowered GHRH receptor levels. The combination of MIA-690 with temozolomide synergistically blunted the viability of GH3-GHRHR and AtT20 cells. Moreover, MIA-690 reduced both basal and GHRH-induced secretion of GH and intracellular cAMP levels. Finally, GHRH antagonists inhibited cell viability in human primary GH- and ACTH-PA cell cultures. Overall, our results suggest that GHRH antagonists, either alone or in combination with pharmacological treatments, may be considered for further development as therapy for PAs.
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Affiliation(s)
- Iacopo Gesmundo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Giuseppina Granato
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Antonio C. Fuentes-Fayos
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Clara V. Alvarez
- Centro de Investigaciones Médicas (CIMUS) e Instituto de Investigaciones Sanitarias, University of Santiago de Compostela and Complexo Hospitalario Universitario of Santiago de Compostela, 14004 Santiago de Compostela, Spain; (C.V.A.); (C.D.)
| | - Carlos Dieguez
- Centro de Investigaciones Médicas (CIMUS) e Instituto de Investigaciones Sanitarias, University of Santiago de Compostela and Complexo Hospitalario Universitario of Santiago de Compostela, 14004 Santiago de Compostela, Spain; (C.V.A.); (C.D.)
| | - Maria Chiara Zatelli
- Section of Endocrinology and Internal Medicine, Department of Medical Sciences, University of Ferrara, 15706 Ferrara, Italy;
| | - Noemi Congiusta
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Dana Banfi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Nunzia Prencipe
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Sheila Leone
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (S.L.); (L.B.)
| | - Luigi Brunetti
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (S.L.); (L.B.)
| | - Justo P. Castaño
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Raúl M. Luque
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Renzhi Cai
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
| | - Wei Sha
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
| | - Ezio Ghigo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Andrew V. Schally
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
- Comprehensive Cancer Center, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Division of Hematology/Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Department of Pathology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Riccarda Granata
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
- Correspondence:
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GPR101 drives growth hormone hypersecretion and gigantism in mice via constitutive activation of G s and G q/11. Nat Commun 2020; 11:4752. [PMID: 32958754 PMCID: PMC7506554 DOI: 10.1038/s41467-020-18500-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
Growth hormone (GH) is a key modulator of growth and GH over-secretion can lead to gigantism. One form is X-linked acrogigantism (X-LAG), in which infants develop GH-secreting pituitary tumors over-expressing the orphan G-protein coupled receptor, GPR101. The role of GPR101 in GH secretion remains obscure. We studied GPR101 signaling pathways and their effects in HEK293 and rat pituitary GH3 cell lines, human tumors and in transgenic mice with elevated somatotrope Gpr101 expression driven by the rat Ghrhr promoter (GhrhrGpr101). Here, we report that Gpr101 causes elevated GH/prolactin secretion in transgenic GhrhrGpr101 mice but without hyperplasia/tumorigenesis. We show that GPR101 constitutively activates not only Gs, but also Gq/11 and G12/13, which leads to GH secretion but not proliferation. These signatures of GPR101 signaling, notably PKC activation, are also present in human pituitary tumors with high GPR101 expression. These results underline a role for GPR101 in the regulation of somatotrope axis function.
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Cheng Y, Chen T, Song J, Qi Q, Wang C, Xi Q, Liu S, Hao L, Zhang Y. miR-709 inhibits GHRP6 induced GH synthesis by targeting PRKCA in pituitary. Mol Cell Endocrinol 2020; 506:110763. [PMID: 32084499 DOI: 10.1016/j.mce.2020.110763] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/02/2020] [Accepted: 02/18/2020] [Indexed: 02/07/2023]
Abstract
Pituitary growth hormone (GH) plays an essential role in processes of organism growth and metabolism. MicroRNA (miRNA) could also participate in diverse biological processes. However, the role of miRNA in the regulation of pituitary GH during the growth process remains unclear. In this study, we firstly confirmed that the second highly expressed pituitary miRNA (miR-709) significantly inhibited the GH synthesis and suppressed the viability of GH3 cells. The bioinformatics analysis and dual luciferase report system were used to ascertain the PRKCA is the direct target gene of miR-709, which is the coding gene of PKCα. Then the transcription and translation levels of Prkca were obvious reduced by the over-expression of miR-709 in GH3 cells, followed by the inhibition of the transcription factor (CREB1) of Gh1 gene and the ERK1/2 signaling pathway or the possible cross-talk signaling pathway (cAMP/PKA signaling pathway) detected by western blot, suggesting that ERK1/2 maybe an important factor involved in the GH3 cell viability mediated by PKCα. At last, GHRP6 increased PKCα and GH expression but reduced miR-709 expression in vitro and vivo assays, and this conclusion was further confirmed by the result of GHRP6 attenuated the inhibition of miR-709 on GH expression. These findings will provide new molecular mechanism on the regulation of pituitary GH.
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Affiliation(s)
- Yunyun Cheng
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Jie Song
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Qien Qi
- School of Life Science and Engineering, Foshan University, Foshan, 528231, China
| | - Chunli Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Songcai Liu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Linlin Hao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China.
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China.
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Ashton C, Rhie SK, Carmichael JD, Zada G. Role of KCNAB2 expression in modulating hormone secretion in somatotroph pituitary adenoma. J Neurosurg 2020; 134:787-793. [PMID: 32109873 DOI: 10.3171/2019.12.jns192435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/17/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Prior profiling of the human pituitary adenoma (PA) DNA methylome showed the potassium channel subunit-encoding gene KCNAB2 to be highly differentially methylated between nonfunctional PAs (NFPAs) and growth hormone (GH)-secreting PAs, with greater KCNAB2 methylation detected in secretory PAs. KCNAB2 encodes an aldo-keto reductase that, among other things, negatively regulates members of the voltage-gated potassium channel (Kv) family. In this study, the authors aimed to determine whether modulation of Kcnab2 expression would alter GH secretion in the GH3 mammosomatotroph rat cell line. In addition, they examined whether dosing GH3 cells with the antiarrhythmic drug quinidine, a known inhibitor of Kv and voltage-gated sodium channels, would affect hormonal secretion. METHODS Previously generated RNA-seq data were reanalyzed to compare KCNAB2 expression levels in human NFPAs and GH-secreting PAs. Kcnab2 was overexpressed in GH3 cells using plasmid transfection and knocked down using shRNA, with confirmation by quantitative polymerase chain reaction (qPCR). GH concentrations in cell culture supernatants collected 24 hours after cell seeding were measured using enzyme-linked immunosorbent assay (ELISA). Separately, quinidine was administered to GH3 cells at graduated doses. GH and prolactin concentrations in supernatants collected 48 hours after quinidine treatment were measured by fluorometric immunoassay. RESULTS Modulation of expression at the transcript level in GH3 cells resulted in proportionate changes in the expression of GH mRNA and secretion of GH peptide, as confirmed by qPCR and ELISA. Specifically, partial knockdown of Kcnab2 was associated with fewer GH RNA transcripts and less GH secretion compared with controls, while augmentation of Kcnab2 expression was associated with more GH transcripts and secretion than the controls. Administration of quinidine (≥ 50 µM) reduced both GH and prolactin secretion in a dose-dependent fashion (p ≤ 0.05). CONCLUSIONS GH secretion in a somatotroph cell line is partially dependent on KCNAB2 gene expression and may be mitigated in vitro by quinidine. These results collectively suggest a potential new target and pharmacological candidate to be considered in the development of clinical therapeutics for acromegaly.
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Affiliation(s)
| | | | - John D Carmichael
- 3Medicine (Division of Endocrinology), Keck School of Medicine, University of Southern California, Los Angeles, California
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Brigante G, Riccetti L, Lazzaretti C, Rofrano L, Sperduti S, Potì F, Diazzi C, Prodam F, Guaraldi G, Lania AG, Rochira V, Casarini L. Abacavir, nevirapine, and ritonavir modulate intracellular calcium levels without affecting GHRH-mediated growth hormone secretion in somatotropic cells in vitro. Mol Cell Endocrinol 2019; 482:37-44. [PMID: 30543878 DOI: 10.1016/j.mce.2018.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/15/2018] [Accepted: 12/10/2018] [Indexed: 11/17/2022]
Abstract
Growth Hormone (GH) deficiency is frequent in HIV-infected patients treated with antiretroviral therapy. We treated GH3 cells with antiretrovirals (nevirapine, ritonavir or abacavir sulfate; 100 pM-1 mM range), after transfection with human growth hormone releasing hormone (GHRH) receptor cDNA. Cells viability, intracellular cAMP, phosphorylation of CREB and calcium increase, GH production and secretion were evaluated both in basal condition and after GHRH, using MTT, bioluminescence resonance energy transfer, western blotting and ELISA. Antiretroviral treatment did not affect GHRH 50% effective dose (EC50) calculated for 30-min intracellular cAMP increase (Mann-Whitney's U test; p ≥ 0.05; n = 4) nor 15-min CREB phosphorylation. The kinetics of GHRH-mediated, rapid intracellular calcium increase was perturbed by pre-incubation with drugs, while GHRH failed to induce the ion increase in ritonavir pre-treated cells (ANOVA; p < 0.05; n = 3). Antiretrovirals did not impact 24-h intracellular and extracellular GH levels (ANOVA; p ≥ 0.05; n = 3). We demonstrated the association between antiretrovirals and intracellular calcium increase, without consequences on somatotrope cells viability and GH synthesis. Overall, these results suggest that antiretrovirals may not directly impact on GH axis in HIV-infected patients.
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Affiliation(s)
- Giulia Brigante
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
| | - Laura Riccetti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Clara Lazzaretti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Laura Rofrano
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Samantha Sperduti
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Francesco Potì
- Department of Medicine and Surgery - Unit of Neurosciences, University of Parma, Parma, Italy
| | - Chiara Diazzi
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
| | - Flavia Prodam
- Unit of Paediatrics, Endocrinology, Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Giovanni Guaraldi
- Department of Medical and Surgical Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Andrea G Lania
- Endocrine Unit, IRCCS Humanitas Clinical Institute, Rozzano, Humanitas University, Rozzano, Italy
| | - Vincenzo Rochira
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Medical Specialties, Azienda Ospedaliero-Universitaria di Modena, Modena, Italy.
| | - Livio Casarini
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
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Faggi L, Giustina A, Tulipano G. Effects of metformin on cell growth and AMPK activity in pituitary adenoma cell cultures, focusing on the interaction with adenylyl cyclase activating signals. Mol Cell Endocrinol 2018; 470:60-74. [PMID: 28962892 DOI: 10.1016/j.mce.2017.09.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 09/21/2017] [Accepted: 09/25/2017] [Indexed: 01/27/2023]
Abstract
For a few years we have been investigating AMP-activated protein kinase (AMPK) as a target for drug therapy of GH-secreting pituitary adenomas. Aim of this study was to investigate the direct effects of metformin, which causes AMPK activation in different cell types, on rat pituitary adenoma cell growth and on related cell signalling pathways. Our results suggest that metformin can exert a growth-inhibitory activity in rat pituitary tumor cells mediated by AMPK activation, although multiple mechanisms are most likely involved. Membrane proteins, including growth factor receptors, are valuable targets of AMPK. The inhibition of the mTOR-p70S6 kinase signalling pathway plays a role in the suppressive effect of metformin on pituitary tumor cell growth. Metformin did not affect the MTT reduction activity in energetic stress conditions. Finally, metformin was still able to induce AMPK activation and to inhibit cell growth in cells treated with forskolin and in transfected cells overexpressing GHRH-receptor and treated with GHRH. Hence, adenylyl cyclase over-activation does not account for the lack of response of some human pituitary tumors to AMPK-activating compounds in vitro.
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Affiliation(s)
- Lara Faggi
- Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Andrea Giustina
- Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Italy; Endocrine Service, University of Brescia, Italy
| | - Giovanni Tulipano
- Unit of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Italy.
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Chu WK, Law KS, Chan SO, Yam JCS, Chen LJ, Zhang H, Cheung HS, Block NL, Schally AV, Pang CP. Antagonists of growth hormone-releasing hormone receptor induce apoptosis specifically in retinoblastoma cells. Proc Natl Acad Sci U S A 2016; 113:14396-14401. [PMID: 27911838 PMCID: PMC5167144 DOI: 10.1073/pnas.1617427113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Retinoblastoma (RB) is the most common intraocular cancer in children worldwide. Current treatments mainly involve combinations of chemotherapies, cryotherapies, and laser-based therapies. Severe or late-stage disease may require enucleation or lead to fatality. Recently, RB has been shown to arise from cone precursor cells, which have high MDM2 levels to suppress p53-mediated apoptosis. This finding leads to the hypothesis that restoring apoptosis mechanisms in RBs could specifically kill the cancer cells without affecting other retinal cells. We have previously reported involvement of an extrapituitary signaling pathway of the growth hormone-releasing hormone (GHRH) in the retina. Here we show that the GHRH receptor (GHRH-R) is highly expressed in RB cells but not in other retinal cells. We induced specific apoptosis with two different GHRH-R antagonists, MIA-602 and MIA-690. Importantly, these GHRH-R antagonists do not trigger apoptosis in other retinal cells such as retinal pigmented epithelial cells. We delineated the gene expression profiles regulated by GHRH-R antagonists and found that cell proliferation genes and apoptotic genes are down- and up-regulated, respectively. Our results reveal the involvement of GHRH-R in survival and proliferation of RB and demonstrate that GHRH-R antagonists can specifically kill the RB cells.
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Affiliation(s)
- Wai Kit Chu
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Ka Sin Law
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Sun On Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Jason Cheuk Sing Yam
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Li Jia Chen
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Hao Zhang
- Cancer Research Center, Shantou University Medical College, Shantou 515041, Guangdong, China
- Department of Biotherapy, Affiliated Cancer Hospital of Shantou University Medical College, Shantou 515041, China
- Tumor Tissue Bank, Affiliated Cancer Hospital of Shantou University Medical College, Shantou 515041, China
| | - Herman S Cheung
- Department of Biomedical Engineering, University of Miami, Miami, FL 33146
| | - Norman L Block
- Department of Biomedical Engineering, University of Miami, Miami, FL 33146
- Department of Pathology, University of Miami Medical School, Miami, FL 33136
| | - Andrew V Schally
- Department of Pathology, University of Miami Medical School, Miami, FL 33136;
- Veterans Affairs Medical Center, Miami, FL 33125
- Department of Medicine, Divisions of Hematology and Oncology and Endocrinology, University of Miami School of Medicine, Miami, FL 33136
- Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Miami, FL 33136
| | - Chi Pui Pang
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong;
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Wang B, Qin C, Zhang C, Jia J, Sun C, Li W. Differential involvement of signaling pathways in the regulation of growth hormone release by somatostatin and growth hormone-releasing hormone in orange-spotted grouper (Epinephelus coioides). Mol Cell Endocrinol 2014; 382:851-9. [PMID: 24183819 DOI: 10.1016/j.mce.2013.10.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 10/20/2013] [Accepted: 10/22/2013] [Indexed: 11/25/2022]
Abstract
Somatostatin is the most effective inhibitor of GH release, and GHRH was recently identified as one of the primary GH-releasing factors in teleosts. In this study, we analyzed the possible intracellular transduction pathways that are involved in the mechanisms induced by SRIF and GHRH to regulate GH release. Using a pharmacological approach, the blockade of the PLC/IP/PKC pathway reversed the SRIF-induced inhibition of GH release but did not affect the GHRH-induced stimulation of GH release. Furthermore, SRIF reduced the GH release induced by two PKC activators. Inhibitors of the AC/cAMP/PKA pathway reversed both the SRIF- and GHRH-induced effects on GH release. Moreover, the GH release evoked by forskolin and 8-Br-cAMP were completely abolished by SRIF. The blockade of the NOS/NO pathway attenuated the GHRH-induced GH release but had minimal effects on the inhibitory actions of SRIF. In addition, inhibitors of the sGC/cGMP pathway did not modify the SRIF- or GHRH-induced regulation of GH release. Taken together, these findings indicate that the SRIF-induced inhibition of GH release is mediated by both the PLC/IP/PKC and the AC/cAMP/PKA pathways and not by the NOS/NO/sGC/cGMP pathway. In contrast, the GHRH-induced stimulation of GH secretion is mediated by both the AC/cAMP/PKA and the NOS/NO pathways and is independent of the sGC/cGMP pathway and the PLC/IP/PKC system.
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Affiliation(s)
- Bin Wang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Chaobin Qin
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Cong Zhang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jirong Jia
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Caiyun Sun
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Wensheng Li
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
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10
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Tulipano G, Faggi L, Losa M, Mortini P, Spinello M, Sibilia V, Pagani F, Cocchi D, Giustina A. Effects of AMPK activation and combined treatment with AMPK activators and somatostatin on hormone secretion and cell growth in cultured GH-secreting pituitary tumor cells. Mol Cell Endocrinol 2013; 365:197-206. [PMID: 23116772 DOI: 10.1016/j.mce.2012.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 10/18/2012] [Accepted: 10/18/2012] [Indexed: 12/25/2022]
Abstract
We investigated the effects of the AMPK activator AICAR as compared to somatostatin-14 on cell viability and GH secretion in human GH-secreting pituitary adenomas in vitro and in rat GH3 cells. Overnight treatment with AICAR increased phospho-(threonine-172) AMPK levels (activated AMPK) in cultured human adenomas. As to the effects on cell viability, four adenomas out of 15 were responsive to AICAR (0.4mM) and five adenomas were responsive to SS-14 (100 nM). One adenoma was responsive to both somatostatin and AICAR. The effects of cotreatment with SS-14 and AICAR were investigated in eight adenomas. In two adenomas, the effects of AICAR+SS-14 did not exceed the effect of AICAR. In two adenomas which were not responsive to either AICAR or SS-14, the cotreatment was able to reduce cell viability versus control. Two adenomas were not responsive to any treatment. As to the effects on GH secretion, nine adenomas out of 15 were responsive to AICAR. Twelve adenomas were responsive to SS-14. Eight adenomas were responsive to both AICAR and SS-14. Cotreatment exceeded the effect of single treatments in 4 out of 10 adenomas. In GH3 cells, AICAR reduced the activity of p70S6 kinase, which plays an important role in cell growth. SS-14 did not affect significantly AMPK phosphorylation and p70S6K activity but it was able to enhance the inhibitory effect of AICAR on phospho-S6 levels. Moreover, AICAR and SS-14 reduced ERK phosphorylation with a different time course. The combined treatment reduced phospho-ERK levels at any time point.
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Affiliation(s)
- Giovanni Tulipano
- Pharmacology Unit, Department of Biomedical Sciences and Biotechnologies, University of Brescia, Italy.
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11
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Molecular morphology of pituitary cells, from conventional immunohistochemistry to fluorescein imaging. Molecules 2011; 16:3618-35. [PMID: 21540793 PMCID: PMC6263291 DOI: 10.3390/molecules16053618] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 04/25/2011] [Accepted: 04/26/2011] [Indexed: 11/16/2022] Open
Abstract
In situ hybridization (ISH) at the electron microscopic (EM) level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. EM-ISH is considered to be an important tool for clarifying the intracellular localization of mRNA and the exact site of pituitary hormone synthesis on the rough endoplasmic reticulum. A combined ISH and immunohistochemistry (IHC) under EM (EM-ISH&IHC) approach has sufficient ultrastructural resolution, and provides two-dimensional images of the subcellular localization of pituitary hormone and its mRNA in a pituitary cell. The advantages of semiconductor nanocrystals (quantum dots, Qdots) and confocal laser scanning microscopy (CLSM) enable us to obtain three-dimensional images of the subcellular localization of pituitary hormone and its mRNA. Both EM-ISH&IHC and ISH & IHC using Qdots and CLSM are useful for understanding the relationships between protein and mRNA simultaneously in two or three dimensions. CLSM observation of rab3B and SNARE proteins such as SNAP-25 and syntaxin has revealed that both rab3B and SNARE system proteins play important roles and work together as the exocytotic machinery in anterior pituitary cells. Another important issue is the intracellular transport and secretion of pituitary hormone. We have developed an experimental pituitary cell line, GH3 cell, which has growth hormone (GH) linked to enhanced yellow fluorescein protein (EYFP). This stable GH3 cell secretes GH linked to EYFP upon stimulation by Ca2+ influx or Ca2+ release from storage. This GH3 cell line is useful for the real-time visualization of the intracellular transport and secretion of GH. These three methods from conventional immunohistochemistry and fluorescein imaging allow us to consecutively visualize the process of transcription, translation, transport and secretion of anterior pituitary hormone.
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12
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Kim JM, Lee YH, Ku CR, Lee EJ. The cyclic pentapeptide d-Arg3FC131, a CXCR4 antagonist, induces apoptosis of somatotrope tumor and inhibits tumor growth in nude mice. Endocrinology 2011; 152:536-44. [PMID: 21147876 DOI: 10.1210/en.2010-0642] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The interaction between the chemokine stromal cell-derived factor 1 and its receptor CXCR4 plays an important role in GH production and cell proliferation in normal and tumorous pituitary somatotrope cells. Therefore, the chemokine receptor CXCR4 could be an attractive target for antitumor drugs in patients with acromegaly. A synthetic antagonist of CXCR4, cyclic pentapeptide d-Arg3FC131 (c[Gly1-d-Tyr2-d-Arg3-Arg4-Nal5]) significantly inhibited GH production and proliferation of GH3 somatotrope tumor cells in vitro. It also induced apoptosis of GH3 cells through activation of the caspase-3 pathway. Systemic administration of d-Arg3FC131 inhibited the growth of GH3 cell xenografts in immunodeficient nude mice by inducing apoptosis and suppressing the proliferation of tumor cells. These results indicate that d-Arg3FC131 might have potential for the treatment of pituitary tumors producing excess GH in patients with acromegaly.
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Affiliation(s)
- Jeong Mo Kim
- Severance Hospital Integrative Research Institute for Cerebral & Cardiovascular Diseases and Department of Internal Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea
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13
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Noh TW, Jeong HJ, Lee MK, Kim TS, Kim SH, Lee EJ. Predicting recurrence of nonfunctioning pituitary adenomas. J Clin Endocrinol Metab 2009; 94:4406-13. [PMID: 19820025 DOI: 10.1210/jc.2009-0471] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Nonfunctioning pituitary adenomas are commonly diagnosed as large tumors. Most are detected incidentally during imaging studies or as a result of neurological manifestations. Depending on severity, most patients with large tumors require surgery and adjunctive therapies because of the high rate of tumor recurrence. The ability to predict the recurrence of a tumor at the time of the initial surgery would be helpful in deciding whether adjunctive therapy is necessary and decreasing morbidity. We investigated the use of several cellular markers for predicting the recurrence of nonfunctioning pituitary adenomas. OBJECTIVE A tissue array block was made using tissue from 35 cases of nonfunctioning pituitary adenomas (16 cases with early recurrence <or=4 yr after surgery, 10 cases with late recurrence >4 yr after surgery, and nine cases without recurrence). Levels of tumor tissue cellular markers associated with cell proliferation or apoptosis were analyzed, and immunohistochemical study of cellular markers was conducted using sectioned slides from the tissue array block. RESULTS High Ki-67 and TUNEL labeling indexes were associated with recurrent nonfunctioning pituitary adenomas. Tumors with a high level of expression of phospho-Akt, phospho-p44/42 MAPK, and PTTG1 were associated with early recurrence. However, high levels of expression of phospho-CREB and ZAC1 were inversely associated with recurrence. CONCLUSIONS Tumors with high levels of expression of phospho-Akt and phospho-p44/42 MAPK and low levels of expression of phospho-CREB and ZAC1 should be followed closely and may require adjunctive therapy to prevent tumor recurrence.
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Affiliation(s)
- Tae-Woong Noh
- Pituitary Tumor Clinic and Institute of Endocrinology, Yonsei Brain Research Institute, Yonsei University College of Medicine, 120-752 Seoul, Korea
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14
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Solloso A, Barreiro L, Seoane R, Nogueira E, Cañibano C, Alvarez CV, Zalvide J, Diéguez C, Pombo CM. GHRH proliferative action on somatotrophs is cell-type specific and dependent on Pit-1/GHF-1 expression. J Cell Physiol 2008; 215:140-50. [PMID: 17941086 DOI: 10.1002/jcp.21295] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To investigate the mechanisms by which the hypothalamic peptide GHRH influences cell division, we analyzed its effects on the proliferation of two different cell lines: CHO-4, an ovary-derived cell line, and GH3, a pituitary-derived cell line. We found that GHRH induces the proliferation of pituitary-derived cells but inhibits the proliferation of ovary-derived cells. We further characterized this dual effect of GHRH to find that the cytoplasmic signals induced by this hormone are similar in both cell lines. Moreover, in CHO-4 cells GHRH stimulates two well-known positive cell cycle regulators, c-myc and cyclin D1, but is unable to induce the degradation of the negative cell cycle regulator p27(Kip1). Significantly, when the Pit-1/GHF-1 gene is exogenously expressed in CHO-4 cells, the negative effect of GHRH on the proliferation of these cells is attenuated. Furthermore, when the levels of Pit-1 are downregulated by siRNA in GH3-GHRHR cells, the positive effects of GHRH on the proliferation of these cells are diminished. These findings add to our understanding of the molecules involved in the regulation of cell proliferation by GHRH, as we demonstrate for the first time that Pit-1 is not only required to drive the expression of the GHRH receptor, as previously described, but is also needed for the downstream effects that occur after its activation to modulate cell proliferation. These data suggest that the regulation of cell proliferation in response to a specific growth factor depends in certain cell populations on the presence of a tissue-specific transcription factor.
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Affiliation(s)
- A Solloso
- Department of Physiology, School of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
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15
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Kim E, Sohn S, Lee M, Park C, Jung J, Park S. Effect of gsp oncogene on somatostatin receptor subtype 1 and 2 mRNA levels in GHRH-responsive GH3 cells. Pituitary 2005; 8:155-62. [PMID: 16379030 DOI: 10.1007/s11102-005-5245-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Growth hormone releasing hormone (GHRH) signals via G protein-coupled receptors (GHRH-R) to enhance intracellular Galphas/adenylyl cyclase/cAMP signaling, which in turn has positive effects on GH synthesis and release, as well as proliferation of the GH-producing cells of the anterior pituitary gland. Some GH-producing pituitary tumors express a constitutively active mutant form of Galphas (gsp oncogene). It has been reported that these tumors are more responsive to octreotide therapy. In this study we used a rat GH-producing cell line (GH3) stably transfected with the human GHRH-R cDNA (GH3-GHRHR cells) as a model to study the effects of gsp oncogene on somatostatin (SRIH) receptor subtype 1 and 2 (sst1 and sst2) mRNA levels. Transient transfection of gsp oncogene in GH3-GHRHR cells for 48 h increased intracellular cAMP levels and GH release. Phosphodiesterase (PDE) 4, sst1 and sst2 mRNA levels were increased by G protein mutation as assessed by real-time RT-PCR. Increased PDE mRNA levels in gsp-transfected cells may be a compensatory mechanism to the constitutive activation of cAMP-dependent pathway by G protein mutation and is consistent with reports of higher PDE expression in human pituitary tumor that express gsp. Our data suggest that higher expression of sst1 and sst2 mRNA induced by the gsp oncogene may be a mechanism by which gsp-positive tumors show a greater response to SRIH. GH3 cells permanently transfected with GHRH-R can be used for in vitro studies of actions of GHRH.
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MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/metabolism
- Animals
- Bucladesine/pharmacology
- Cell Line, Tumor
- Cells, Cultured
- Cholera Toxin/pharmacology
- Colforsin/pharmacology
- Cyclic Nucleotide Phosphodiesterases, Type 4
- GTP-Binding Protein alpha Subunits, Gs/genetics
- Growth Hormone-Releasing Hormone/pharmacology
- Octreotide/pharmacology
- Oncogenes/physiology
- Pituitary Gland, Anterior
- RNA, Messenger/metabolism
- Rats
- Receptors, Neuropeptide/biosynthesis
- Receptors, Pituitary Hormone-Regulating Hormone/biosynthesis
- Receptors, Somatostatin/genetics
- Transfection
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Affiliation(s)
- Eunhee Kim
- Department of Pharmacology and Institute for Basic Medical Science, Kyunghee University School of Medicine, Seoul, 130-701, Korea
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16
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Abstract
The transactivation domain of the cAMP response element-binding protein (CREB) consists of two major domains. The glutamine-rich Q2 domain, which interacts with the general transcription factor TAFII130/135, is sufficient for the recruitment of a functional RNA polymerase II complex and allows basal transcriptional activity. The kinase-inducible domain, however, mediates signal-induced activation of CREB-mediated transcription. It is generally believed that recruitment of the coactivators CREB-binding protein (CBP) and p300 after signal-induced phosphorylation of this domain at serine-133 strongly enhances CREB-dependent transcription. Transcriptional activity of CREB can also be potentiated by phosphoserine-133-independent mechanisms, and not all stimuli that provoke phosphorylation of serine-133 stimulate CREB-dependent transcription. This review presents an overview of the diversity of stimuli that induce CREB phosphorylation at Ser-133, focuses on phosphoserine-133-dependent and -independent mechanisms that affect CREB-mediated transcription, and discusses different models that may explain the discrepancy between CREB Ser-133 phosphorylation and activation of CREB-mediated transcription.
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Affiliation(s)
- Mona Johannessen
- Department of Biochemistry, Institute of Medical Biology, University of Tromsø, N-9037, Norway
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17
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Jirawatnotai S, Aziyu A, Osmundson EC, Moons DS, Zou X, Kineman RD, Kiyokawa H. Cdk4 is indispensable for postnatal proliferation of the anterior pituitary. J Biol Chem 2004; 279:51100-6. [PMID: 15456744 DOI: 10.1074/jbc.m409080200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For proper development and tissue homeostasis, cell cycle progression is controlled by multilayered mechanisms. Recent studies using knock-out mice have shown that animals can develop relatively normally with deficiency for each of the G1/S-regulatory proteins, D-type and E-type cyclins, cyclin-dependent kinase 4 (Cdk4), and Cdk2. Although Cdk4-null mice show no embryonic lethality, they exhibit specific endocrine phenotypes, i.e. dwarfism, infertility, and diabetes. Here we have demonstrated that Cdk4 plays an essential non-redundant role in postnatal proliferation of the anterior pituitary. Pituitaries from wild-type and Cdk4-null embryos at embryonic day 17.5 are morphologically indistinguishable with similar numbers of cells expressing a proliferating marker, Ki67, and cells expressing a differentiation marker, growth hormone. In contrast, anterior pituitaries of Cdk4-null mice at postnatal 8 weeks are extremely hypoplastic with markedly decreased numbers of Ki67+ cells, suggesting impaired cell proliferation. Pituitary hyperplasia induced by transgenic expression of human growth hormone-releasing hormone (GHRH) is significantly diminished in the Cdk4+/- genetic background and completely abrogated in the Cdk4-/- background. Small interfering RNA (siRNA)-mediated knockdown of Cdk4 inhibits GHRH-induced proliferation of GH3 somato/lactotroph cells with restored expression of GHRH receptors. Cdk4 siRNA also inhibits estrogen-dependent cell proliferation in GH3 cells and closely related GH4 cells. In contrast, Cdk6 siRNA does not diminish proliferation of these cells. Furthermore, Cdk4 siRNA does not affect GHRH-induced proliferation of mouse embryonic fibroblasts or estrogen-dependent proliferation of mammary carcinoma MCF-7 cells. Taken together, Cdk4 is dispensable for prenatal development of the pituitary or proliferation of other non-endocrine tissues but indispensable specifically for postnatal proliferation of somato/lactotrophs.
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Affiliation(s)
- Siwanon Jirawatnotai
- Department of Biochemistry, University of Illinois College of Medicine, Chicago, Illinois 60607, USA
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18
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Lee EJ, Jakacka M, Duan WR, Chien PY, Martinson F, Gehm BD, Jameson JL. Adenovirus-directed Expression of Dominant Negative Estrogen Receptor Induces Apoptosis in Breast Cancer Cells and Regression of Tumors in Nude Mice. Mol Med 2001. [DOI: 10.1007/bf03401968] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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