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Kalashyan M, Raghunathan K, Oller H, Bayer MT, Jimenez L, Roland JT, Kolobova E, Hagen SJ, Goldsmith JD, Shub MD, Goldenring JR, Kaji I, Thiagarajah JR. Patient-derived enteroids provide a platform for the development of therapeutic approaches in microvillus inclusion disease. J Clin Invest 2023; 133:e169234. [PMID: 37643022 PMCID: PMC10575727 DOI: 10.1172/jci169234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 08/22/2023] [Indexed: 08/31/2023] Open
Abstract
Microvillus inclusion disease (MVID), caused by loss-of-function mutations in the motor protein myosin Vb (MYO5B), is a severe infantile disease characterized by diarrhea, malabsorption, and acid/base instability, requiring intensive parenteral support for nutritional and fluid management. Human patient-derived enteroids represent a model for investigation of monogenic epithelial disorders but are a rare resource from MVID patients. We developed human enteroids with different loss-of function MYO5B variants and showed that they recapitulated the structural changes found in native MVID enterocytes. Multiplex immunofluorescence imaging of patient duodenal tissues revealed patient-specific changes in localization of brush border transporters. Functional analysis of electrolyte transport revealed profound loss of Na+/H+ exchange (NHE) activity in MVID patient enteroids with near-normal chloride secretion. The chloride channel-blocking antidiarrheal drug crofelemer dose-dependently inhibited agonist-mediated fluid secretion. MVID enteroids exhibited altered differentiation and maturation versus healthy enteroids. γ-Secretase inhibition with DAPT recovered apical brush border structure and functional Na+/H+ exchange activity in MVID enteroids. Transcriptomic analysis revealed potential pathways involved in the rescue of MVID cells including serum/glucocorticoid-regulated kinase 2 (SGK2) and NHE regulatory factor 3 (NHERF3). These results demonstrate the utility of patient-derived enteroids for developing therapeutic approaches to MVID.
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Affiliation(s)
- Meri Kalashyan
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Krishnan Raghunathan
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Haley Oller
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marie-Theres Bayer
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lissette Jimenez
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Congenital Enteropathy Program, Boston Children’s Hospital, Boston, Massachusetts, USA
- PediCODE Consortium, as detailed in Supplemental Acknowledgments
| | - Joseph T. Roland
- Section of Surgical Sciences and
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Elena Kolobova
- Section of Surgical Sciences and
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Susan J. Hagen
- Department of Surgery, Division of Surgical Sciences, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey D. Goldsmith
- PediCODE Consortium, as detailed in Supplemental Acknowledgments
- Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mitchell D. Shub
- Department of Child Health, University of Arizona College of Medicine–Phoenix, and Division of Gastroenterology, Phoenix Children’s Hospital, Phoenix, Arizona, USA
| | - James R. Goldenring
- PediCODE Consortium, as detailed in Supplemental Acknowledgments
- Section of Surgical Sciences and
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Nashville VA Medical Center, Nashville, Tennessee, USA
| | - Izumi Kaji
- PediCODE Consortium, as detailed in Supplemental Acknowledgments
- Section of Surgical Sciences and
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jay R. Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Congenital Enteropathy Program, Boston Children’s Hospital, Boston, Massachusetts, USA
- PediCODE Consortium, as detailed in Supplemental Acknowledgments
- Harvard Digestive Disease Center, Boston, Massachusetts, USA
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2
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Kalashyan M, Raghunathan K, Oller H, Theres MB, Jimenez L, Roland JT, Kolobova E, Hagen SJ, Goldsmith JD, Shub MD, Goldenring JR, Kaji I, Thiagarajah JR. Therapy Development for Microvillus Inclusion Disease using Patient-derived Enteroids. bioRxiv 2023:2023.01.28.526036. [PMID: 36747680 PMCID: PMC9900906 DOI: 10.1101/2023.01.28.526036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Microvillus Inclusion Disease (MVID), caused by loss-of-function mutations in the motor protein Myosin Vb (MYO5B), is a severe infantile disease characterized by diarrhea, malabsorption, and acid-base instability, requiring intensive parenteral support for nutritional and fluid management. Human patient-derived enteroids represent a model for investigation of monogenic epithelial disorders but are a rare resource from MVID patients. We developed human enteroids with different loss-of function MYO5B variants and showed that they recapitulated the structural changes found in native MVID enterocytes. Multiplex Immunofluorescence imaging of patient duodenal tissues revealed patient-specific changes in localization of brush border transporters. Functional analysis of electrolyte transport revealed profound loss of Na + /H + exchange (NHE) activity in MVID patient enteroids with near-normal chloride secretion. The chloride channel-blocking anti-diarrheal drug, Crofelemer, dose-dependently inhibited agonist-mediated fluid secretion. MVID enteroids exhibited altered differentiation and maturation versus healthy enteroids. Inhibition of Notch signaling with the γ-secretase inhibitor, DAPT, recovered apical brush border structure and functional Na + /H + exchange activity in MVID enteroids. Transcriptomic analysis revealed potential pathways involved in the rescue of MVID cells including serum- and glucocorticoid-induced protein kinase 2 (SGK2), and NHE regulatory factor 3 (NHERF3). These results demonstrate the utility of patient-derived enteroids for developing therapeutic approaches to MVID. Conflict-of-interest statement The authors have declared that no conflict of interest exists.
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Affiliation(s)
- Meri Kalashyan
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
| | - Krishnan Raghunathan
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
| | - Haley Oller
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
| | - Marie-Bayer Theres
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
| | - Lissette Jimenez
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
- Congenital Enteropathy Program, Boston Children’s Hospital, Boston, MA
- PediCoDE Consortium
| | - Joseph T. Roland
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Elena Kolobova
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Susan J Hagen
- Department of Surgery, Division of Surgical Sciences, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey D. Goldsmith
- Department of Pathology, Boston Children’s Hospital; Harvard Medical School, Boston, MA
- PediCoDE Consortium
| | - Mitchell D. Shub
- Department of Child Health University of Arizona College of Medicine-Phoenix and Division of Gastroenterology, Phoenix Children’s
| | - James R. Goldenring
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee
- Nashville VA Medical Center, Nashville, TN
- PediCoDE Consortium
| | - Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee
- PediCoDE Consortium
| | - Jay R. Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital; Harvard Medical School, Boston, MA
- Congenital Enteropathy Program, Boston Children’s Hospital, Boston, MA
- Harvard Digestive Disease Center, Boston MA
- PediCoDE Consortium
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Li J, Yu H, Wang X, Ye Y, Fang W, Ding N, Mi L, Ping L, Wang X, Song Y, Zhu J. The Serum- and Glucocorticoid-Inducible Kinase 1 (SGK1) as a Novel Therapeutic Target in Mantle Cell Lymphoma. Cancer Control 2022; 29:10732748221143881. [PMID: 36519740 PMCID: PMC9761230 DOI: 10.1177/10732748221143881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
INTRODUCTION Mantle cell lymphoma (MCL) is an aggressive and incurable B-cell-derived malignant disease. MCL is treated using general chemotherapy; however, disease progression and relapse are common; thus, the development of novel therapeutic targets for treatment of MCL is urgently required. Serum- and glucocorticoid-inducible kinase 1 (SGK1) is involved in various cellular activities, and its dysregulation contributes to the pathogenesis of multiple types of cancer. However, little is known regarding its functional roles and associated molecular mechanisms in MCL. METHODS SGK1 inhibition mediated by either shRNA or treatment with SGK1 inhibitor (GSK650394) was conducted in MCL cell lines. Western blotting analysis was performed to figure out the expression of related proteins. MCL-cell-derived xenograft models were constructed to evaluate the anti-tumor effects of SGK1 inhibition or/and Bruton's tyrosine kinase (BTK) inhibition in vivo. RESULTS In this study, it was shown that inhibition of SGK1 significantly reduced cell proliferation, invasion and migration, increased apoptosis and blocked cell cycle progression in MCL cells. Furthermore, SGK1 inhibition significantly reduced the activation of ERK, AKT/mTOR, JAK2/STAT3 and the NF-κB signaling pathways. Using MCL-cell-derived xenograft mice models, SGK1 inhibition decreased tumor cell proliferation and tumor growth. Importantly, SGK1 overexpression significantly promoted xenograft tumor growth. Moreover, simultaneous inhibition of SGK1 and Bruton tyrosine kinase (BTK) resulted in synergistic anti-tumor effects on MCL both in vitro and in vivo. CONCLUSION SGK1 may be a novel candidate therapeutic target and simultaneous inhibition of SGK1 and BTK may be a promising therapeutic strategy for MCL patients. Further pre-clinical and even clinical studies of SGK1 inhibitor or combination with BTK inhibitor are essential.
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Affiliation(s)
- Jiao Li
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Hui Yu
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Xing Wang
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Yingying Ye
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Wei Fang
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Ning Ding
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Lan Mi
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Lingyan Ping
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Xiaogan Wang
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Yuqin Song
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China
| | - Jun Zhu
- Key Laboratory of Carcinogenesis
and Translational Research (Ministry of Education), Department of lymphoma,
Peking
University Cancer Hospital, Institute,
Beijing, China,Jun Zhu and Yuqin Song, Key Laboratory of
Carcinogenesis and Translational Research (Ministry of Education), Department of
Lymphoma, Peking University Cancer Hospital & Institute, 52 Fucheng Road,
Haidian, Beijing 100142, China. ;
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Piran M, Sepahi N, Moattari A, Rahimi A, Ghanbariasad A. Systems Biomedicine of Primary and Metastatic Colorectal Cancer Reveals Potential Therapeutic Targets. Front Oncol 2021; 11:597536. [PMID: 34249670 PMCID: PMC8263939 DOI: 10.3389/fonc.2021.597536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 05/31/2021] [Indexed: 12/23/2022] Open
Abstract
Colorectal cancer (CRC) is one of the major causes of cancer deaths across the world. Patients' survival at time of diagnosis depends mainly on stage of the tumor. Therefore, understanding the molecular mechanisms from low-grade to high-grade stages of cancer that lead to cellular migration from one tissue/organ to another tissue/organ is essential for implementing therapeutic approaches. To this end, we performed a unique meta-analysis flowchart by identifying differentially expressed genes (DEGs) between normal, primary (primary sites), and metastatic samples (Colorectal metastatic lesions in liver and lung) in some Test datasets. DEGs were employed to construct a protein-protein interaction (PPI) network. A smaller network containing 39 DEGs was then extracted from the PPI network whose nodes expression induction or suppression alone or in combination with each other would inhibit tumor progression or metastasis. These DEGs were then verified by gene expression profiling, survival analysis, and multiple Validation datasets. We suggested for the first time that downregulation of mitochondrial genes, including ETHE1, SQOR, TST, and GPX3, would help colorectal cancer cells to produce more energy under hypoxic conditions through mechanisms that are different from "Warburg Effect". Augmentation of given antioxidants and repression of P4HA1 and COL1A2 genes could be a choice of CRC treatment. Moreover, promoting active GSK-3β together with expression control of EIF2B would prevent EMT. We also proposed that OAS1 expression enhancement can induce the anti-cancer effects of interferon-gamma, while suppression of CTSH hinders formation of focal adhesions. ATF5 expression suppression sensitizes cancer cells to anchorage-dependent death signals, while LGALS4 induction recovers cell-cell junctions. These inhibitions and inductions would be another combinatory mechanism that inhibits EMT and cell migration. Furthermore, expression inhibition of TMPO, TOP2A, RFC3, GINS1, and CKS2 genes could prevent tumor growth. Besides, TRIB3 suppression would be a promising target for anti-angiogenic therapy. SORD is a poorly studied enzyme in cancer, found to be upregulated in CRC. Finally, TMEM131 and DARS genes were identified in this study whose roles have never been interrogated in any kind of cancer, neither as a biomarker nor curative target. All the mentioned mechanisms must be further validated by experimental wet-lab techniques.
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Affiliation(s)
- Mehran Piran
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
- Department of Bacteriology and Virology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Neda Sepahi
- Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran
| | - Afagh Moattari
- Department of Bacteriology and Virology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Rahimi
- Bioinformatics and Computational Biology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Ghanbariasad
- Noncommunicable Diseases Research Center, Fasa University of Medical Sciences, Fasa, Iran
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Ueki S, Fujishima F, Kumagai T, Ishida H, Okamoto H, Takaya K, Sato C, Taniyma Y, Kamei T, Sasano H. GR, Sgk1, and NDRG1 in esophageal squamous cell carcinoma: their correlation with therapeutic outcome of neoadjuvant chemotherapy. BMC Cancer 2020; 20:161. [PMID: 32106831 PMCID: PMC7045479 DOI: 10.1186/s12885-020-6652-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 02/17/2020] [Indexed: 12/21/2022] Open
Abstract
Background Esophageal squamous cell carcinoma (ESCC) is a highly malignant neoplasm. The glucocorticoid (GC)-glucocorticoid receptor (GR) pathway plays pivotal roles in cellular response to various stresses of tumor cells, including chemotherapy. However, the status of the GC-GR pathway in ESCC, including its correlation with chemotherapeutic responses, is largely unknown. Methods GR, serum-and glucocorticoid-regulated kinase 1 (Sgk1), and N-myc down regulation gene 1 (NDRG1) were immunolocalized in 98 patients with ESCC who had undergone esophagectomy following neoadjuvant chemotherapy (NAC) with 2 courses of 5-fluorouracil + cisplatin. We also examined biopsy specimens before NAC in 42 cases and compared the results between those before and after NAC. Results Overall survival (OS) of the patients treated with surgery following NAC was significantly shorter in the group with high GR than that with low GR status (P = 0.0473). Both OS and disease-free survival (DFS) were significantly shorter in both Sgk1- and NDRG1-high groups than in the low groups (OS: Sgk1, P = 0.0055; NDRG1, P = 0.0021; DFS: Sgk1, P = 0.0240; NDRG1, P = 0.0086). Biopsy specimens before NAC showed significantly shorter DFS in the high Sgk1 group (P = 0.0095), while both OS and DFS were shorter in the high NDRG1 group (OS, P = 0.0233; DFS, P = 0.0006) than in the respective low groups. In the high NDRG1 group of biopsy specimens before NAC, the tumor reduction rate by NAC was significantly attenuated (P = 0.021). Conclusions High GR, Sgk1, and NDRG1 statuses in ESCC after NAC was significantly associated with an overall worse prognosis, with no significant changes in their expression levels before and after NAC. Therefore, increased activity of the GC-GR pathway with enhanced induction of Sgk1 and NDRG1 in carcinoma cells play pivotal roles in tumor progression and development of chemo-resistance in patients with ESCC undergoing NAC.
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Affiliation(s)
- Shunsuke Ueki
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. .,Department of Pathology, Tohoku University Graduate School of Medicine, 1-2 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
| | - Fumiyoshi Fujishima
- Department of Pathology, Tohoku University Graduate School of Medicine, 1-2 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Takuro Kumagai
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Hirotaka Ishida
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Hiroshi Okamoto
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Kai Takaya
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Chiaki Sato
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Yusuke Taniyma
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Takashi Kamei
- Department of Gastrointestinal Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Graduate School of Medicine, 1-2 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
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Abstract
Forkhead box O (FOXO) and p53 proteins are transcription factors that regulate diverse signalling pathways to control cell cycle, apoptosis and metabolism. In the last decade both FOXO and p53 have been identified as key players in aging, and their misregulation is linked to numerous diseases including cancers. However, many of the underlying molecular mechanisms remain mysterious, including regulation of ageing by FOXOs and p53. Several activities appear to be shared between FOXOs and p53, including their central role in the regulation of cellular senescence. In this review, we will focus on the recent advances on the link between FOXOs and p53, with a particular focus on the FOXO4‐p53 axis and the role of FOXO4/p53 in cellular senescence. Moreover, we discuss potential strategies for targeting the FOXO4‐p53 interaction to modulate cellular senescence as a drug target in treatment of aging‐related diseases and morbidity.
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Affiliation(s)
- Benjamin Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,BioTechMed, Graz, Austria
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7
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Liang X, Lan C, Jiao G, Fu W, Long X, An Y, Wang K, Zhou J, Chen T, Li Y, Xu J, Huang Q, Xu B, Xiao J. Therapeutic inhibition of SGK1 suppresses colorectal cancer. Exp Mol Med 2017; 49:e399. [PMID: 29170478 PMCID: PMC5704191 DOI: 10.1038/emm.2017.184] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 05/07/2017] [Accepted: 05/23/2017] [Indexed: 01/19/2023] Open
Abstract
Colorectal cancer (CRC) is one of the leading causes of death worldwide. Thus, the development of new therapeutic targets for CRC treatment is urgently needed. SGK1 is involved in various cellular activities, and its dysregulation can result in multiple cancers. However, little is known about its roles and associated molecular mechanisms in CRC. In present study, we found that SGK1 was highly expressed in tumor tissues compared with peri-tumor samples from CRC patients. In vitro experiments revealed that SGK1 overexpression promoted colonic tumor cell proliferation and migration and inhibited cell apoptosis induced by 5-fluorouracil (5-FU), while SGK1 shRNA and inhibitors showed the inverse effects. Using CRC xenograft mice models, we demonstrated that knockdown or therapeutic inhibition of SGK1 repressed tumor cell proliferation and tumor growth. Moreover, SGK1 inhibitors increased p27 expression and promoted p27 nuclear accumulation in colorectal cancer cells, and p27 siRNAs could attenuate the repression of CRC cell proliferation induced by SGK1 inhibitors. Collectively, SGK1 promotes colorectal cancer development via regulation of CRC cell proliferation, migration and survival. Inhibition of SGK1 represents a novel strategy for the treatment of CRC.
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Affiliation(s)
- Xuchun Liang
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Chunling Lan
- Department of Chemistry, Qianweichang College, Innovative Drug Research Center, Shanghai University, Shanghai, China
| | - Guanming Jiao
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Wencheng Fu
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Xuesha Long
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Yu An
- Department of Chemistry, Qianweichang College, Innovative Drug Research Center, Shanghai University, Shanghai, China
| | - Kejin Wang
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Jinzhe Zhou
- Department of General Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ting Chen
- Department of Dermatology, First Affiliated Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yongqin Li
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
| | - Jiahong Xu
- Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qi Huang
- Department of General Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bin Xu
- Department of Chemistry, Qianweichang College, Innovative Drug Research Center, Shanghai University, Shanghai, China
| | - Junjie Xiao
- Regeneration and Ageing Lab, School of Life Science, Shanghai University, Shanghai, China
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8
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Zhu L, Thompson J, Ma F, Eudy J, Jones C. Effects of the synthetic corticosteroid dexamethasone on bovine herpesvirus 1 productive infection. Virology 2017; 505:71-79. [PMID: 28237765 DOI: 10.1016/j.virol.2017.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/06/2017] [Accepted: 02/14/2017] [Indexed: 10/20/2022]
Abstract
Sensory neurons are a primary site for life-long latency of bovine herpesvirus 1 (BoHV-1). The synthetic corticosteroid dexamethasone induces reactivation from latency and productive infection, in part because the BoHV-1 genome contains more than 100 glucocorticoid receptor (GR) responsive elements (GREs). Two GREs in the immediate early transcription unit 1 promoter are required for dexamethasone induction. Recent studies also demonstrated that the serum and glucocorticoid receptor protein kinase (SGK) family stimulated BoHV-1 replication. Consequently, we hypothesized that dexamethasone influences several aspects of productive infection. In this study, we demonstrated that dexamethasone increased expression of the immediate early protein bICP4, certain late transcripts, and UL23 (thymidine kinase) by four hours after infection. SGK1 expression and Akt phosphorylation were also stimulated during early stages of infection and dexamethasone treatment further increased this effect. These studies suggest that stress, as mimicked by dexamethasone treatment, has the potential to stimulate productive infection by multiple pathways.
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Affiliation(s)
- Liqian Zhu
- Oklahoma State University, Center for Veterinary Health Sciences, Department of Veterinary Pathobiology, Stillwater, OK 74078, USA; College of Veterinary Medicine and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, 48 Wenhui East Road, Yangzhou 225009, China
| | - Jesse Thompson
- University of Nebraska, Nebraska Center for Virology, Morisson Life Science Center, Lincoln, NE 68583-09065, USA
| | - Fangrui Ma
- University of Nebraska, Nebraska Center for Virology, Morisson Life Science Center, Lincoln, NE 68583-09065, USA
| | - James Eudy
- Department of Genetics Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Clinton Jones
- Oklahoma State University, Center for Veterinary Health Sciences, Department of Veterinary Pathobiology, Stillwater, OK 74078, USA
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9
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Kook I, Jones C. The serum and glucocorticoid-regulated protein kinases (SGK) stimulate bovine herpesvirus 1 and herpes simplex virus 1 productive infection. Virus Res 2016; 222:106-112. [PMID: 27297663 DOI: 10.1016/j.virusres.2016.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/12/2023]
Abstract
Serum and glucocorticoid-regulated protein kinases (SGK) are serine/threonine protein kinases that contain a catalytic domain resembling other protein kinases: AKT/protein kinase B, protein kinase A, and protein kinase C-Zeta for example. Unlike these constitutively expressed protein kinases, SGK1 RNA and protein levels are increased by growth factors and corticosteroids. Stress can directly stimulate SGK1 levels as well as stimulate bovine herpesvirus 1 (BoHV-1) and herpes simplex virus 1 (HSV-1) productive infection and reactivation from latency suggesting SGK1 can stimulate productive infection. For the first time, we provide evidence that a specific SGK inhibitor (GSK650394) significantly reduced BoHV-1 and HSV-1 replication in cultured cells. Proteins encoded by the three BoHV-1 immediate early genes (bICP0, bICP4, and bICP22) and two late proteins (VP16 and gE) were consistently reduced by GSK650394 during early stages of productive infection. In summary, these studies suggest SGK may stimulate viral replication following stressful stimuli.
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Affiliation(s)
- Insun Kook
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Morisson Life Science Center, RM234, Lincoln, NE 68583-09065, USA
| | - Clinton Jones
- Oklahoma State University, Center for Veterinary Health Sciences, Department of Veterinary Pathobiology, Stillwater, OK 74078, USA.
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10
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Abstract
The predominant function of the tumor suppressor p53 is transcriptional regulation. It is generally accepted that p53-dependent transcriptional activation occurs by binding to a specific recognition site in promoters of target genes. Additionally, several models for p53-dependent transcriptional repression have been postulated. Here, we evaluate these models based on a computational meta-analysis of genome-wide data. Surprisingly, several major models of p53-dependent gene regulation are implausible. Meta-analysis of large-scale data is unable to confirm reports on directly repressed p53 target genes and falsifies models of direct repression. This notion is supported by experimental re-analysis of representative genes reported as directly repressed by p53. Therefore, p53 is not a direct repressor of transcription, but solely activates its target genes. Moreover, models based on interference of p53 with activating transcription factors as well as models based on the function of ncRNAs are also not supported by the meta-analysis. As an alternative to models of direct repression, the meta-analysis leads to the conclusion that p53 represses transcription indirectly by activation of the p53-p21-DREAM/RB pathway.
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Key Words
- CDE, cell cycle-dependent element
- CDKN1A
- CHR, cell cycle genes homology region
- ChIP, chromatin immunoprecipitation
- DREAM complex
- DREAM, DP, RB-like, E2F4, and MuvB complex
- E2F/RB complex
- HPV, human papilloma virus
- NF-Y, Nuclear factor Y
- cdk, cyclin-dependent kinase
- genome-wide meta-analysis
- p53
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Affiliation(s)
- Martin Fischer
- a Molecular Oncology; Medical School ; University of Leipzig ; Leipzig , Germany
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11
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Xiao D, Yang D, Guo L, Lu W, Charpentier M, Yan B. Regulation of carboxylesterase-2 expression by p53 family proteins and enhanced anti-cancer activities among 5-fluorouracil, irinotecan and doxazolidine prodrug. Br J Pharmacol 2015; 168:1989-99. [PMID: 23373735 DOI: 10.1111/bph.12125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 11/05/2012] [Accepted: 12/10/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE For four decades, 5-fluorouracil (5-FU) has been a major anti-cancer medicine. This drug is increasingly used with other anti-cancer agents such as irinotecan. Irinotecan and many others such as PPD (pentyl carbamate of p-aminobenzyl carbamate of doxazolidine) require activation by carboxylesterase-2 (CES2). 5-FU, on the other hand, reportedly induces CES2 in colorectal tumour lines. The aims of this study were to determine the molecular basis for the induction and to ascertain interactive cell-killing activity between 5-FU and ester prodrugs. EXPERIMENTAL APPROACH Colorectal and non-colorectal lines and xenografts were treated with 5-FU and the expression of CES2 was determined. Cell-killing activity of irinotecan and PPD were determined in the presence or absence of CES2 inhibitor. Several molecular experiments were used to determine the molecular basis for the induction. KEY RESULTS Without exceptions, robust induction was detected in cell lines expressing functional p53. High-level induction was also detected in xenografts. 5-FU pretreatment significantly increased cell-killing activity of irinotecan and PPD. Molecular experiments established that the induction was achieved by both transactivation and increased mRNA stability through p53. Either p63 or p73, functionally related to p53, did not support the transactivation. CONCLUSIONS AND IMPLICATIONS The results in this study suggest that FOLFIRI, a common regimen combining irinotecan and 5-FU, should switch the dosing sequence, namely from 5-FU to irinotecan, to enhance hydrolytic activation of irinotecan. This modified order likely reduces the dose of anti-cancer agents, thus minimizing overall toxicity. The results also conclude that p53 family members act differently in regulating gene expression.
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Affiliation(s)
- Da Xiao
- Department of Biomedical and Pharmaceutical Sciences, Center for Pharmacogenomics and Molecular Therapy, University of Rhode Island, Kingston, RI 02881, USA
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12
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Savry A, Carre M, Berges R, Rovini A, Pobel I, Chacon C, Braguer D, Bourgarel-Rey V. Bcl-2-enhanced efficacy of microtubule-targeting chemotherapy through Bim overexpression: implications for cancer treatment. Neoplasia 2013; 15:49-60. [PMID: 23358890 DOI: 10.1593/neo.121074] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 11/18/2022] Open
Abstract
Bcl-2 is commonly overexpressed in tumors, where it is often associated with unfavorable outcome. However, it has also been linked to a favorable sensitivity to microtubule-targeting agents (MTAs). We show that Bcl-2-overexpressing lung and breast cancer cells were more sensitive to both paclitaxel and vinorelbine. Bcl-2 over-expression also significantly potentiated in vivo efficacy of paclitaxel, in terms of tumor volume decrease and survival benefits, in models of nude mice bearing lung cancer xenografts. To further investigate this favorable effect of Bcl-2, a genomic approach was taken. It revealed that Bcl-2 overexpression induced up-regulation of the proapoptotic protein Bim in lung cancer cells and that, conversely, Bcl-2 silencing decreased Bim expression level. A gene regulation study implicated the transcription factor Forkhead box-containing protein, class O3a in Bim up-regulation. Lastly, we show that Bim was responsible for MTA-triggered lung cancer cell death through a dynamin-related protein 1-mediated mitochondrial fragmentation. The Bcl-2-governed Bim induction evidence offers for the first time an explanation for the favorable higher sensitivity to treatment shown by Bcl-2-overexpressing cells. We suggest that Bim could be a powerful predictive factor for tumor response to MTA chemotherapy. Our data also give new insight into some failures in the efficacy of therapies targeted against Bcl-2.
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13
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O'Keeffe BA, Cilia S, Maiyar AC, Vaysberg M, Firestone GL. The serum- and glucocorticoid-induced protein kinase-1 (Sgk-1) mitochondria connection: identification of the IF-1 inhibitor of the F(1)F(0)-ATPase as a mitochondria-specific binding target and the stress-induced mitochondrial localization of endogenous Sgk-1. Biochimie 2013; 95:1258-65. [PMID: 23402912 PMCID: PMC3684451 DOI: 10.1016/j.biochi.2013.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 01/30/2013] [Indexed: 12/28/2022]
Abstract
The expression, localization and activity of the serum- and glucocorticoid-induced protein kinase, Sgk-1, are regulated by multiple hormonal and environmental cues including cellular stress. Biochemical fractionation and indirect immunofluorescence demonstrated that sorbitol induced hyperosmotic stress stimulated expression and triggered the localization of endogenous Sgk-1 into the mitochondria of NMuMG mammary epithelial cells. The immunofluorescence pattern of endogenous Sgk-1 was similar to that of a green fluorescent linked fusion protein linked to the N-terminal Sgk-1 fragment that encodes the mitochondrial targeting signal. In the presence or absence of cellular stress, exogenously expressed wild type Sgk-1 efficiently compartmentalized into the mitochondria demonstrating the mitochondrial import machinery per se is not stressed regulated. Co-immunoprecipitation and GST-pull down assays identified the IF-1 mitochondrial matrix inhibitor of the F1F0-ATPase as a new Sgk-1 binding partner, which represents the first observed mitochondrial target of Sgk-1. The Sgk-1/IF-1 interaction requires the 122-176 amino acid region within the catalytic domain of Sgk-1 and is pH dependent, occurring at neutral pH but not at slightly acidic pH, which suggests that this interaction is dependent on mitochondrial integrity. An in vitro protein kinase assay showed that the F1F0-ATPase can be directly phosphorylated by Sgk-1. Taken together, our results suggest that stress-induced Sgk-1 localizes to the mitochondria, which permits access to physiologically appropriate mitochondrial interacting proteins and substrates, such as IF-1 and the F1F0-ATPase, as part of the cellular stressed induced program.
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Affiliation(s)
- Bridget A O'Keeffe
- Department of Molecular and Cell Biology and the Cancer Research Laboratory, 591 LSA, University of California at Berkeley, Berkeley, CA 94720-3200, USA
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14
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Colabardini AC, Brown NA, Savoldi M, Goldman MHS, Goldman GH. Functional characterization of Aspergillus nidulans ypkA, a homologue of the mammalian kinase SGK. PLoS One 2013; 8:e57630. [PMID: 23472095 PMCID: PMC3589345 DOI: 10.1371/journal.pone.0057630] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/23/2013] [Indexed: 11/19/2022] Open
Abstract
The serum- and glucocorticoid-regulated protein kinase (SGK) is an AGC kinase involved in signal cascades regulated by glucocorticoid hormones and serum in mammals. The Saccharomyces cerevisiae ypk1 and ypk2 genes were identified as SGK homologues and Ypk1 was shown to regulate the balance of sphingolipids between the inner and outer plasma membrane. This investigation characterized the Aspergillus nidulans YPK1 homologue, YpkA, representing the first filamentous fungal YPK1 homologue. Two conditional mutant strains were constructed by replacing the endogenous ypk1 promoter with two different regulatable promoters, alcA (from the alcohol dehydrogenase gene) and niiA (from the nitrate reductase gene). Both constructs confirmed that ypkA was an essential gene in A. nidulans. Repression of ypkA caused decreased radial growth, a delay in conidial germination, deficient polar axis establishment, intense branching during late stages of growth, a lack of asexual spores, and a terminal phenotype. Membrane lipid polarization, endocytosis, eisosomes and vacuolar distribution were also affected by ypkA repression, suggesting that YpkA plays a role in hyphal morphogenesis via coordinating the delivery of cell membrane and wall constituents to the hyphal apex. The A. nidulans Pkh1 homologue pkhA was also shown to be an essential gene, and preliminary genetic analysis suggested that the ypkA gene is not directly downstream of pkhA or epistatic to pkhA, rather, ypkA and pkhA are genetically independent or in parallel. BarA is a homologue of the yeast Lag1 acyl-CoA-dependent ceramide synthase, which catalyzes the condensation of phytosphingosine with a fatty acyl-CoA to form phytoceramide. When barA was absent, ypkA repression was lethal to the cell. Therefore, there appears to be a genetic interaction between ypkA, barA, and the sphingolipid synthesis. Transcriptional profiling of ypkA overexpression and down-regulation revealed several putative YpkA targets associated with the observed phenotypes.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, São Paulo, Brazil
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- * E-mail: address:
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15
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Vilasco M, Communal L, Mourra N, Courtin A, Forgez P, Gompel A. Glucocorticoid receptor and breast cancer. Breast Cancer Res Treat 2011; 130:1-10. [PMID: 21818591 DOI: 10.1007/s10549-011-1689-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 07/18/2011] [Indexed: 12/25/2022]
Abstract
Stress enhances glucocorticoid (GC) synthesis, which alters inflammation and immune responses, as well as cellular proliferation and apoptosis in a number of tissues. Increasingly, stress has been associated with cancer progression, and in particular in breast cancer. Consequently, an operational glucocorticoid receptor system in breast tissue influences breast cancer development. In this review, we summarize the data on the GC/GR system in normal and tumoral breast tissue. We also review the molecular mechanisms by which GCs control apoptosis and proliferation in breast cancer models and how GCs alter the chemotherapy of breast cancer treatment when used in combination. Finally, we discuss the participation of GR in breast tumorigenesis under hormone replacement therapy.
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Affiliation(s)
- Myriam Vilasco
- INSERM-UPMC, UMRS 938, Hôpital Saint-Antoine, 184 rue du Faubourg Saint Antoine, 75012, Paris, France
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16
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McCaig C, Potter L, Abramczyk O, Murray JT. Phosphorylation of NDRG1 is temporally and spatially controlled during the cell cycle. Biochem Biophys Res Commun 2011; 411:227-34. [DOI: 10.1016/j.bbrc.2011.06.092] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 06/13/2011] [Indexed: 01/26/2023]
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17
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Abstract
The serum and glucocorticoid kinase (SGK) family of serine/threonine kinases consists of three isoforms, SGK-1, SGK-2 and SGK-3. This family of kinases is highly homologous to the AKT kinase family, sharing similar upstream activators and downstream targets. SGKs have been implicated in the regulation of cell growth, proliferation, survival and migration: cellular processes that are dysregulated in cancer. Furthermore, SGKs lie downstream of phosphoinositide-3-kinase (PI3Kinase) signalling and interact at various levels with RAS/RAF/ERK signalling, two pathways that are involved in promoting tumorigenesis. Recent evidence suggests that mutant PI3Kinase can induce tumorigenesis through an AKT-independent but SGK3-dependent mechanism, thus implicating SGKs as potential players in malignant transformation. Here, we will review the current state of knowledge on the regulation of the SGKs and their role in normal cell physiology and transformation with a particular focus on SGK3.
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Affiliation(s)
- Maressa A Bruhn
- Growth Control and Differentiation Program, Peter MacCallum Cancer Centre, Melbourne, 3002, Victoria, Australia
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18
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Lee EJ, Shin SH, Chun J, Hyun S, Kim Y, Kang SS. The modulation of TRPV4 channel activity through its Ser 824 residue phosphorylation by SGK1. Anim Cells Syst (Seoul) 2010. [DOI: 10.1080/19768354.2010.486939] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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19
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Diwan BA, Timofeeva O, Rice JM, Yang Y, Sharma N, Fortini ME, Wang H, Perantoni AO. Inheritance of susceptibility to induction of nephroblastomas in the Noble rat. Differentiation 2009; 77:424-32. [PMID: 19281789 DOI: 10.1016/j.diff.2008.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 11/25/2022]
Abstract
Noble (Nb) strain rats are susceptible to nephroblastoma induction with transplacental exposure to direct-acting alkylating agent N-nitrosoethylurea (ENU), while F344 strain rats are highly resistant. To study the inheritance of susceptibility to induction of these embryonal renal tumors, fetal Nb and F344 rats and F1, F2 and reciprocal backcross hybrids were exposed transplacentally to ENU once on day 18 of gestation. Nephroblastomas developed in 53% of Nb offspring with no apparent gender difference, while no nephroblastomas developed in inbred F344 offspring. F1 and F2 hybrid offspring had intermediate responses, 28% and 30%, respectively. Nephroblastoma incidence in the offspring of F1 hybrids backcrossed to the susceptible strain Nb was 46%, while that in F1 hybrids backcrossed to resistant strain F344 was much lower (16%). Carcinogenic susceptibility is therefore consistent with the involvement of one major autosomal locus; the operation of a gene dosage effect; and a lack of simple Mendelian dominance for either susceptibility or resistance. Since established Wilms tumor-associated suppressor genes, Wt1 and Wtx, were not mutated in normal or neoplastic tissues, genomic profiling was performed on isolated Nb and F344 metanephric progenitors to identify possible predisposing factors to nephroblastoma induction. Genes preferentially elevated in expression in Nb rat progenitors included Wnt target genes Epidermal growth factor receptor, Inhibitor of DNA binding 2, and Jagged1, which were further increased in nephroblastomas. These studies demonstrate the value of this model for genetic analysis of nephroblastoma development and implicate both the Wnt and Notch pathways in its pathogenesis.
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Affiliation(s)
- Bhalchandra A Diwan
- Basic Research Program, Science Applications International Corporation-Frederick, Inc., National Cancer Institute, Frederick, MD 21702, USA
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20
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Abstract
p53 controls the cellular response to genotoxic stress through multiple mechanisms. We report here that p53 regulates DUSP1, a dual-specific threonine and tyrosine phosphatase with stringent substrate specificity for mitogen-activated protein kinase (MAPK). DUSP1 is a potent inhibitor of MAPK activity through dephosphorylation of MAPK. In a colon cancer cell line containing inducible ectopic p53, DUSP1 protein level is significantly increased upon activation of p53, leading to cell death in response to nutritional stress. In mouse embryo fibroblast cells, DUSP1 protein abundance is greatly increased after oxidative stress in a p53-dependent manner and also when apoptosis is triggered. We show that p53 induces the activity of a human DUSP1 regulatory region. Furthermore, p53 can physically interact with the DUSP1 regulatory region in vivo, and p53 binds to a 10-bp perfect palindromic site in this DUSP1 regulatory region. We show that overexpression of DUSP1 or inhibition of MAPK activity significantly increases cellular susceptibility to oxidative damage. These findings indicate that p53 is a transcriptional regulator of DUSP1 in stress responses. Our results reveal a mechanism whereby p53 selectively regulates target genes and suggest a way in which subgroups of those target genes might be controlled independently.
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Affiliation(s)
- Yu-Xin Liu
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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21
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Abstract
FoxO transcription factors are an evolutionary conserved subfamily of the forkhead transcription factors, characterized by the forkhead DNA-binding domain. FoxO factors regulate a number of cellular processes involved in cell-fate decisions in a cell-type- and environment-specific manner, including metabolism, differentiation, apoptosis and proliferation. A key mechanism by which FoxO determines cell fate is through regulation of the cell cycle machinery, and as such the cellular consequence of FoxO deregulation is often manifested through perturbation of the cell cycle. Consequently, the deregulation of FoxO factors is implicated in the development of numerous proliferative diseases, in particular cancer.
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22
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Cornez I, Creppe C, Gillard M, Hennuy B, Chapelle JP, Dejardin E, Merville MP, Close P, Chariot A. Deregulated expression of pro-survival and pro-apoptotic p53-dependent genes upon Elongator deficiency in colon cancer cells. Biochem Pharmacol 2008; 75:2122-34. [PMID: 18430410 DOI: 10.1016/j.bcp.2008.03.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/06/2008] [Accepted: 03/07/2008] [Indexed: 10/22/2022]
Abstract
Elongator, a multi-subunit complex assembled by the IkappaB kinase-associated protein (IKAP)/hELP1 scaffold protein is involved in transcriptional elongation in the nucleus as well as in tRNA modifications in the cytoplasm. However, the biological processes regulated by Elongator in human cells only start to be elucidated. Here we demonstrate that IKAP/hELP1 depleted colon cancer-derived cells show enhanced basal expression of some but not all pro-apoptotic p53-dependent genes such as BAX. Moreover, Elongator deficiency causes increased basal and daunomycin-induced expression of the pro-survival serum- and glucocorticoid-induced protein kinase (SGK) gene through a p53-dependent pathway. Thus, our data collectively demonstrate that Elongator deficiency triggers the activation of p53-dependent genes harbouring opposite functions with respect to apoptosis.
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Abstract
Glucocorticoids (GCs) are provided as co-medication with chemotherapy in breast cancer, albeit
several lines of evidence indicate that their use may have diverse effects and in fact may inhibit
chemosensitivity. The molecular basis of GC-induced resistance to chemotherapy in breast cancer
remains poorly defined. Recent researchers, in an attempt to clarify some aspects of the underlying
pathways, provide convincing evidence that GCs induce effects that are dependent upon the
glucocorticoid-receptor (GR)-mediated transcriptional regulation of specific genes known to play key
roles in cellular/tissue functions, including growth, apoptosis, differentiation, metastasis and
cell survival. In this review, we focus on how GC-induced chemoresistance in breast cancer is
mediated by the GR, unravelling the molecular interplay of GR signalling with other signalling
cascades prevalent in breast cancer. We also include a detailed description of GR structure and
function, summarizing data gained during recent years into the mechanism(s) of the cross-talk
between the GR and other signalling cascades and secondary messengers, via which
GCs exert their pleiotropic effects.
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Affiliation(s)
- Paraskevi Moutsatsou
- Department of Biological Chemistry, Medical School, University of Athens, Athens, Greece.
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Wang J, Yin DP, Liu YX, Baer R, Yin Y. Dual specificity phosphatase 1/CL100 is a direct transcriptional target of E2F-1 in the apoptotic response to oxidative stress. Cancer Res 2007; 67:6737-44. [PMID: 17638884 DOI: 10.1158/0008-5472.can-06-4402] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
E2F-1 mediates apoptosis through transcriptional regulation of its targets. We report here that E2F-1 acts as a direct transcriptional regulator of dual specificity phosphatase 1 (DUSP1; CL100), a threonine and tyrosine phosphatase that inhibits mitogen-activated protein (MAP) kinases. We found that DUSP1 is transcriptionally induced by ectopic E2F-1 expression and that extracellular signal-regulated kinase 1/2 are dephosphorylated in the presence of E2F-1 and DUSP1. E2F-1 mediates apoptosis in the cellular response to oxidative stress. DUSP1 levels are significantly increased in an E2F-1-dependent manner following oxidative stress but not other stresses examined. DUSP1 mediates the cellular response to oxidative stress. We found that E2F-1 binds to chromatin encompassing the DUSP1 promoter and greatly stimulates the promoter activity of the DUSP1 gene. In particular, E2F-1 physically binds to an E2F-1 consensus sequence and a palindromic motif in the DUSP1 promoter. Interestingly, E2F-1 is acetylated following oxidative stress. Our findings show that E2F-1 is a transcriptional activator of DUSP1 and that DUSP1 is a link between E2F-1 and MAP kinases.
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Affiliation(s)
- Jianli Wang
- Department of Radiation Oncology, Center for Radiological Research, College of Physicians and Surgeons, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
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25
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Abstract
TAp73 is a p53 tumor suppressor gene homologue that is known to be mainly involved in apoptosis. We report here that TAp73 is necessary for the cellular response to oxidative stress and that TAp73 functions as a downstream target of p53 in this process. We show that p53 physically interacts with the TAp73 promoter under stress conditions that lead to cell death. Particularly, p53 binds to a palindromic site in the TAp73 promoter, activates the promoter of TAp73, and selectively induces TAp73 transcription. TAp73 expression is highly increased under oxidative stress in a p53-dependent manner. Furthermore, knock-down of TAp73 expression inhibits the cellular apoptotic response to oxidative damage. In contrast, the ectopic expression of TAp73 in p53(-/-) mouse embryonic fibroblasts induces oxidative cell death. Our findings demonstrate that p53 is a direct transcriptional regulator of TAp73. Our data reveal a new pathway for cellular protection against oxidative damage and provide evidence that TAp73 is a stress-response gene and a downstream effector in the p53 pathway.
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Affiliation(s)
- Jianli Wang
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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26
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Abstract
Members of the class O of forkhead box transcription factors (FoxO) have important roles in metabolism, cellular proliferation, stress tolerance and probably lifespan. The activity of FoxOs is tightly regulated by post-translational modifications, including phosphorylation, acetylation and ubiquitylation. Several of the enzymes that regulate the turnover of these post-translational modifications are shared between FoxO and p53. These regulatory enzymes affect FoxO and p53 function in an opposite manner. This shared yet opposing regulatory network between FoxOs and p53 may underlie a 'trade-off' between disease and lifespan.
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Affiliation(s)
- Armando van der Horst
- Department of Physiological Chemistry, Centre for Biomedical Genetics, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
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27
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Failor KL, Desyatnikov Y, Finger LA, Firestone GL. Glucocorticoid-induced degradation of glycogen synthase kinase-3 protein is triggered by serum- and glucocorticoid-induced protein kinase and Akt signaling and controls beta-catenin dynamics and tight junction formation in mammary epithelial tumor cells. Mol Endocrinol 2007; 21:2403-15. [PMID: 17595317 DOI: 10.1210/me.2007-0143] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Glucocorticoid hormones stimulate adherens junction and tight junction formation in Con8 mammary epithelial tumor cells and induce the production of a stable nonphosphorylated beta-catenin protein localized exclusively to the cell periphery. Glycogen synthase kinase-3 (GSK3) phosphorylation of beta-catenin is known to trigger the degradation of this adherens junction protein, suggesting that steroid-activated cascades may be targeting this protein kinase. We now demonstrate that treatment with the synthetic glucocorticoid dexamethasone induces the ubiquitin-26S proteasome-mediated degradation of GSK3 protein with no change in GSK3 transcript levels. In transfected cells, deletion of the N-terminal nine amino acids or mutation of the serine-9 phosphorylation site on GSK3-beta prevented its glucocorticoid-induced degradation. Expression of stabilized GSK3 mutant proteins ablated the glucocorticoid-induced tight junction sealing and resulted in production of a nonphosphorylated beta-catenin that localizes to both the nucleus and the cell periphery in steroid-treated cells. Serine-9 on GSK3 can be phosphorylated by Sgk (serum- and glucocorticoid-induced protein kinase) and by Akt. Expression of dominant-negative forms of either Sgk- or Akt-inhibited glucocorticoid induced GSK3 ubiquitination and degradation and disrupted the dexamethasone-induced effects on beta-catenin dynamics. Furthermore, the steroid-induced tight junction sealing is attenuated in cells expressing dominant-negative forms of either Sgk or Akt, although the effect of blunting Sgk signaling was significantly greater. Taken together, we have uncovered a new cellular cascade in which Sgk and Akt trigger the glucocorticoid-regulated phosphorylation, ubiquitination, and degradation of GSK3, which alters beta-catenin dynamics, leading to the formation of adherens junctions and tight junction sealing.
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Affiliation(s)
- Kim L Failor
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720-3200, USA
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Amato R, Menniti M, Agosti V, Boito R, Costa N, Bond HM, Barbieri V, Tagliaferri P, Venuta S, Perrotti N. IL-2 signals through Sgk1 and inhibits proliferation and apoptosis in kidney cancer cells. J Mol Med (Berl) 2007; 85:707-21. [PMID: 17571248 DOI: 10.1007/s00109-007-0205-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 03/14/2007] [Accepted: 04/16/2007] [Indexed: 10/23/2022]
Abstract
The interleukin-2 is a cytokine that is essential for lymphocytic survival and function. Ectopic expression of the IL-2 receptor in epithelial tissues has been reported previously, although the functional significance of this expression is still being investigated. We provided novel structural and functional information on the expression of the IL-2 receptor in kidney cancer cells and in other normal and neoplastic human epithelial tissues. In A-498 kidney cancer cells, we showed that IL-2 binding to its own receptor triggers a signal transduction pathway leading to the inhibition of proliferation and apoptosis. We found that the inhibition of proliferation is associated with Erk1/2 dephosphorylation, whereas the survival signals appear to be mediated by Sgk1 activation. This investigation focuses on the IL-2 induced regulation of Sgk1 and describes a role of the IL-2 receptor and Sgk1 in the regulation of epithelial tumor cell death and survival.
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Affiliation(s)
- Rosario Amato
- Department of Experimental and Clinical Medicine G. Salvatore, University Magna Graecia, Campus Biomedico, Località Germaneto, Viale Europa, Catanzaro, 88100, Italy
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29
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Abstract
Transcription factor E2F-1 mediates apoptosis and suppresses tumorigenesis. The mechanisms by which E2F-1 functions in these processes are largely unclear. We report here that E2F-1 acts as a transcriptional regulator of MKP-2 (MAPK phosphatase-2), a dual specificity protein phosphatase (DUSP4) with stringent substrate specificity for MAPKs. We show that E2F-1 is required for the cellular apoptotic response to oxidative damage. MKP-2 is greatly increased following oxidative stress, and E2F-1 is necessary for that induction. We found that E2F-1 is physically associated with the MKP-2 promoter and can transactivate the promoter of the MKP-2 gene. Specifically, E2F-1 binds to a perfect palindromic motif in the MKP-2 promoter. Finally, we show that this E2F-1/MKP-2 pathway mediates apoptosis under oxidative stress and that MKP-2 suppresses tumor formation in nude mice. Our findings demonstrate that E2F-1 is a transcriptional activator of MKP-2 and that MKP-2 is an essential cell death mediator in the E2F-1 pathway. Characterization of MKP-2 as a cell death mediator may lead to the development of new strategies for cancer treatment.
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Affiliation(s)
- Jianli Wang
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Wen Hong Shen
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Yan J Jin
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Paul W Brandt-Rauf
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032
| | - Yuxin Yin
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, New York, New York 10032; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032.
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30
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Abstract
Transcription factor p53 regulates its target genes through binding to DNA consensus sequence and activating the promoters of its downstream genes. The conventional p53 consensus binding sequence was defined as two copies of the 10-bp motif 5'-PuPuPuC(A/T)(T/A)GPyPyPy-3' with a spacer of 0 to 13 bp, which exists in the regulatory regions of some p53 target genes. However, there is no such p53 consensus sequence in the promoters of a number of p53-responsive genes, suggesting that there might be other mechanisms whereby p53 transactivates the promoters of its target genes. We report here that p53 uses a novel binding mechanism to regulate the transcription of epithelial cell kinase (ECK), a receptor protein-tyrosine kinase implicated in signal transduction. We show that p53 binds to a 10-bp perfect palindromic decanucleotide (GTGACGTCAC) in the ECK promoter, activates the ECK promoter, and increases the transcription of ECK. This palindrome is required for p53-mediated transactivation of the ECK promoter. ECK is highly responsive to oxidative damage that leads to cell death. Ectopic expression of ECK causes spontaneous apoptosis in breast cancer cells. We found that ectopic expression of a mutant ECK fails to induce apoptosis in cancer cells. Our findings show that p53 is a transcriptional regulator of ECK in mediating apoptosis. The discovery of the novel p53-binding motif in the promoter may lead to the identification of a new class of p53 target genes.
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Affiliation(s)
- Y Jenny Jin
- Department of Radiation Oncology College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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31
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Cordas E, Náray-Fejes-Tóth A, Fejes-Tóth G. Subcellular location of serum- and glucocorticoid-induced kinase-1 in renal and mammary epithelial cells. Am J Physiol Cell Physiol 2007; 292:C1971-81. [PMID: 17202226 DOI: 10.1152/ajpcell.00399.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serum- and glucocorticoid-induced kinase-1 (SGK1) is involved in aldosterone-induced Na(+) reabsorption by increasing epithelial Na(+) channel (ENaC) activity in cortical collecting duct (CCD) cells, but its exact mechanisms of action are unknown. Although several potential targets such as Nedd4-2 have been described in expression systems, endogenous substrates mediating SGK1's physiological effects remain to be identified. In addition, subcellular localization studies of SGK1 have provided controversial results. We determined the subcellular location of SGK1 using SGK1-autofluorescent protein (AFP) fusion proteins. Rabbit CCD (RCCT-28A) cells were transiently transfected with a construct encoding for SGK1-AFP and were stained or cotransfected with markers for various subcellular compartments. In live cells, transiently expressed SGK1-AFP clearly colocalized with the mitochondrial marker rhodamine 123. Similarly, SGK1-AFP colocalized with the mitochondrial marker MitoTracker when stably expressed using a retroviral system in either RCCT-28A cells or the mammary epithelial cell line MCF10A. To determine which region of SGK1 is responsible for this subcellular localization, we generated RCCT-28A cell lines stably expressing SGK1 mutants. The results indicate that the NH(2)-terminal 60-amino acid region of SGK1 is necessary and sufficient for its subcellular localization. Localization of SGK1 to the mitochondria raises the possibility that SGK1 may play a role in regulating energy metabolism.
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Affiliation(s)
- Emily Cordas
- Department of Physiology, Dartmouth Medical School, 1 Medical Center Dr., Lebanon, NH 03756, USA
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32
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Abstract
The phosphatidylinositol 3' kinase (PI3K)-signaling pathway plays a critical role in a variety of cellular responses such as modulation of cell survival, glucose homeostasis, cell division, and cell growth. PI3K generates important lipid second messengers-phosphatidylinositides that are phosphorylated at the 3' position of their inositol ring head-group. These membrane restricted lipids act by binding with high affinity to specific protein domains such as the pleckstrin homology (PH) domain. Effectors of PI3K include molecules that harbor such domains such as phosphoinositide-dependent kinase (PDK1) and protein kinase B (PKB), also termed Akt. The mammalian genome encodes three different PKB genes (alpha, beta, and gamma; Akt1, 2, and 3, respectively) and each is an attractive target for therapeutic intervention in diseases such as glioblastoma and breast cancer. A second family of three protein kinases, termed serum and glucocorticoid-regulated protein kinases (SGKs), is structurally related to the PKB family including regulation by PI3K but lack a PH domain. However, in addition to PH domains, a second class of 3' phosphorylated inositol phospholipid-binding domains exists that is termed Phox homology (PX) domain: this domain is found in one of the SGKs (SGK3). Here, we summarize knowledge of the three SGK isoforms and compare and contrast them to PKB with respect to their possible importance in cellular regulation and potential as therapeutic targets.
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Affiliation(s)
- Maude Tessier
- Department of Medical Biophysics, Samuel Lunenfeld Research Institute, University of Toronto, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
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Lang F, Böhmer C, Palmada M, Seebohm G, Strutz-Seebohm N, Vallon V. (Patho)physiological significance of the serum- and glucocorticoid-inducible kinase isoforms. Physiol Rev 2006; 86:1151-78. [PMID: 17015487 DOI: 10.1152/physrev.00050.2005] [Citation(s) in RCA: 509] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The serum- and glucocorticoid-inducible kinase-1 (SGK1) is ubiquitously expressed and under genomic control by cell stress (including cell shrinkage) and hormones (including gluco- and mineralocorticoids). Similar to its isoforms SGK2 and SGK3, SGK1 is activated by insulin and growth factors via phosphatidylinositol 3-kinase and the 3-phosphoinositide-dependent kinase PDK1. SGKs activate ion channels (e.g., ENaC, TRPV5, ROMK, Kv1.3, KCNE1/KCNQ1, GluR1, GluR6), carriers (e.g., NHE3, GLUT1, SGLT1, EAAT1-5), and the Na+-K+-ATPase. They regulate the activity of enzymes (e.g., glycogen synthase kinase-3, ubiquitin ligase Nedd4-2, phosphomannose mutase-2) and transcription factors (e.g., forkhead transcription factor FKHRL1, beta-catenin, nuclear factor kappaB). SGKs participate in the regulation of transport, hormone release, neuroexcitability, cell proliferation, and apoptosis. SGK1 contributes to Na+ retention and K+ elimination of the kidney, mineralocorticoid stimulation of salt appetite, glucocorticoid stimulation of intestinal Na+/H+ exchanger and nutrient transport, insulin-dependent salt sensitivity of blood pressure and salt sensitivity of peripheral glucose uptake, memory consolidation, and cardiac repolarization. A common ( approximately 5% prevalence) SGK1 gene variant is associated with increased blood pressure and body weight. SGK1 may thus contribute to metabolic syndrome. SGK1 may further participate in tumor growth, neurodegeneration, fibrosing disease, and the sequelae of ischemia. SGK3 is required for adequate hair growth and maintenance of intestinal nutrient transport and influences locomotive behavior. In conclusion, the SGKs cover a wide variety of physiological functions and may play an active role in a multitude of pathophysiological conditions. There is little doubt that further targets will be identified that are modulated by the SGK isoforms and that further SGK-dependent in vivo physiological functions and pathophysiological conditions will be defined.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
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34
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Abstract
The serum/glucocorticoid-induced kinase Sgk1 plays an important role in the regulation of epithelial ion transport. This kinase is very rapidly regulated at the transcriptional level as well as via posttranslational modifications involving phosphorylation by the MAP or PI-3 kinase pathways and/or ubiquitylation. Although Sgk1 is a cell survival kinase, its primary role likely concerns the regulation of epithelial ion transport, as suggested by the phenotype of Sgk1-null mice, which display a defect in Na( homeostasis owing to disturbed renal tubular Na+ handling. In this review we first discuss the molecular, cellular, and regulatory aspects of Sgk1 and its paralogs. We then discuss its roles in the physiology and pathophysiology of epithelial ion transport.
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Affiliation(s)
- Johannes Loffing
- Department of Medicine: Unit of Anatomy, University of Fribourg, CH-1700 Fribourg, Switzerland.
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35
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Sengupta S, Wasylyk B. Physiological and pathological consequences of the interactions of the p53 tumor suppressor with the glucocorticoid, androgen, and estrogen receptors. Ann N Y Acad Sci 2004; 1024:54-71. [PMID: 15265773 DOI: 10.1196/annals.1321.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The p53 tumor suppressor plays a key role in protection from the effects of different physiological stresses (DNA damage, hypoxia, transcriptional defects, etc.), and loss of its activity has dire consequences, such as cancer. Its activity is finely tuned through interactions with other important regulatory circuits in the cell. Recently, striking evidence has emerged for crosstalk with another class of important regulators, the steroid hormone receptors, and in particular the glucocorticoid (GR), androgen (AR), and estrogen (ER) receptors. These receptors are important in maintaining homeostasis in response to internal and external stresses (GR) and in the development, growth, and maintenance of the male and female reproductive systems (AR and ER, respectively). We review how p53 interacts closely with these receptors, to the extent that they share the same E3 ubiquitin ligase, the MDM2 oncoprotein. We discuss the different physiological contexts in which such interactions occur, and also how these interactions have been undermined in various pathological situations. We will describe future areas for research, with special emphasis on GR, and how certain common features, such as cytoplasmic anchoring of p53 by the receptors, may become targets for the development of therapeutic interventions. Given the importance of GR in inflammation, erythropoiesis, and autoimmune diseases, and the importance of AR and ER in prostate and breast cancer (respectively), the studies on p53 interactions with the steroid receptors will be an important domain in the near future.
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Affiliation(s)
- Sagar Sengupta
- Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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36
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Yin Y, Liu YX, Jin YJ, Hall EJ, Barrett JC. PAC1 phosphatase is a transcription target of p53 in signalling apoptosis and growth suppression. Nature 2003; 422:527-31. [PMID: 12673251 DOI: 10.1038/nature01519] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Accepted: 02/20/2003] [Indexed: 11/08/2022]
Abstract
p53 has a role in many cellular processes through the transcriptional regulation of target genes. PAC1 (phosphatase of activated cells 1; also known as dual specificity phosphatase 2, DUSP2) is a dual threonine/tyrosine phosphatase that specifically dephosphorylates and inactivates mitogen-activated protein (MAP) kinases. Here we show that during apoptosis, p53 activates transcription of PAC1 by binding to a palindromic site in the PAC1 promoter. PAC1 transcription is induced in response to serum deprivation and oxidative stress, which results in p53-dependent apoptosis, but not in response to gamma-irradiation, which causes cell cycle arrest. Reduction of PAC1 transcription using small interfering RNA inhibits p53-mediated apoptosis, whereas overexpression of PAC1 increases susceptibility to apoptosis and suppresses tumour formation. Moreover, activation of p53 significantly inhibits MAP kinase activity. We conclude that, under specific stress conditions, p53 regulates transcription of PAC1 through a new p53-binding site, and that PAC1 is necessary and sufficient for p53-mediated apoptosis. Identification of a palindromic motif as a p53-binding site may reveal a novel mechanism whereby p53 regulates its target genes.
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Affiliation(s)
- Yuxin Yin
- Department of Radiation Oncology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, USA
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37
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Abstract
Serum and glucocorticoid-induced kinase 1 (SGK1) activates the epithelial sodium channel (eNaC) in tubules. We examined renal SGK1 abundance in salt-adaptation and in salt-sensitive hypertension. Sprague-Dawley and Dahl salt-sensitive rats were placed on either 8% or 0.3% NaCl diets for 10 days. Plasma aldosterone levels were approximately 2.5-fold greater on 0.3% versus 8% NaCl diets in both rat strains. Both serum and glucocorticoid-induced kinase 1 transcript and protein abundance were less (P<0.01) in Sprague-Dawley rats and greater (P<0.01) in Dahl salt-sensitive rats on 8% versus 0.3% NaCl diets. The cDNA sequences of serum and glucocorticoid-induced kinase 1 in both strains of rat were the same. The present results provide evidence that the abundance of serum and glucocorticoid-induced kinase 1 in rat kidney may play a role in salt adaptation and the pathogenesis of hypertension and suggests that aldosterone is not the primary inducer of SGK1 in the Sprague-Dawley rat.
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Affiliation(s)
- Mariam Farjah
- Department of Medicine, University of Illinois at Chicago, 840 S Wood St, Chicago, Ill 60612, USA
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38
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Maiyar AC, Leong MLL, Firestone GL. Importin-alpha mediates the regulated nuclear targeting of serum- and glucocorticoid-inducible protein kinase (Sgk) by recognition of a nuclear localization signal in the kinase central domain. Mol Biol Cell 2003; 14:1221-39. [PMID: 12631736 PMCID: PMC151592 DOI: 10.1091/mbc.e02-03-0170] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2002] [Revised: 10/17/2002] [Accepted: 11/17/2002] [Indexed: 12/19/2022] Open
Abstract
The transcriptionally regulated serum and glucocorticoid inducible protein kinase (Sgk) is localized to the nucleus in a serum-dependent manner, and a yeast two-hybrid genetic screen uncovered a specific interaction between Sgk and the importin-alpha nuclear import receptor. In vitro GST pull down assays demonstrated a strong and direct association of importin-alpha with endogenous Sgk and exogenously expressed HA-tagged Sgk, whereas both components coimmunoprecipitate and colocalize to the nucleus after serum stimulation. Consistent with an active mechanism of nuclear localization, the nuclear import of HA-Sgk in permeabilized cells required ATP, cytoplasm, and a functional nuclear pore complex. Ectopic addition of a 107 amino acid carboxy-terminal fragment of importin-alpha, which contains the Sgk binding region, competitively inhibited the ability of endogenous importin-alpha to import Sgk into nuclei in vitro. Mutagenesis of lysines by alanine substitution defined a KKAILKKKEEK sequence within the central domain of Sgk between amino acids 131-141 that functions as a nuclear localization signal (NLS) required for the in vitro interaction with importin-alpha and for nuclear import of full-length Sgk in cultured cells. The serum-induced nuclear import of Sgk requires the NLS-dependent recognition of Sgk by importin-alpha as well as the PI3-kinase-dependent phosphorylation of Sgk. Our results define a new role importin-alpha in the stimulus-dependent control of signal transduction by nuclear localized protein kinases.
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Affiliation(s)
- Anita C Maiyar
- Department of Molecular and Cell Biology and The Cancer Research Laboratory, University of California at Berkeley, 94720-3200, USA
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Leong MLL, Maiyar AC, Kim B, O'Keeffe BA, Firestone GL. Expression of the serum- and glucocorticoid-inducible protein kinase, Sgk, is a cell survival response to multiple types of environmental stress stimuli in mammary epithelial cells. J Biol Chem 2003; 278:5871-82. [PMID: 12488318 DOI: 10.1074/jbc.m211649200] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effects of multiple stress stimuli on the cellular utilization of the serum- and glucocorticoid-inducible protein kinase (Sgk) were examined in NMuMg mammary epithelial cells exposed to hyperosmotic stress induced by the organic osmolyte sorbitol, heat shock, ultraviolet irradiation, oxidative stress induced by hydrogen peroxide, or to dexamethasone, a synthetic glucocorticoid that represents a general class of physiological stress hormones. Each of the stress stimuli induced Sgk protein expression with differences in the kinetics and duration of induction and in subcellular localization. The environmental stresses, but not dexamethasone, stimulated Sgk expression through a p38/MAPK-dependent pathway. In each case, a hyperphosphorylated active Sgk protein was produced under conditions in which Akt, the close homolog of Sgk, remained in its non-phosphorylated state. Ectopic expression of wild type Sgk or of the T256D/S422D mutant Sgk that mimics phosphorylation conferred protection against stress-induced cell death in NMuMg cells. In contrast, expression of the T256A/S422A Sgk phosphorylation site mutant has no effect on cell survival. Sgk is known to phosphorylate and negatively regulate pro-apoptotic forkhead transcription factor FKHRL1. The environmental stress stimuli that induce Sgk, but not dexamethasone, strongly inhibited the nuclear transcriptional activity and increased the cytoplasmic retention of FKHRL1. Also, the conditional IPTG inducible expression of wild type Sgk, but not of the kinase dead T256A mutant Sgk, protected Con8 mammary epithelial tumor cells from serum starvation-induced apoptosis. Taken together, our study establishes that induction of enzymatically active Sgk functions as a key cell survival component in response to different environmental stress stimuli.
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Affiliation(s)
- Meredith L L Leong
- Department of Molecular and Cell Biology and The Cancer Research Laboratory, The University of California at Berkeley, Berkeley, California 94720-3200, USA
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Chun J, Kwon T, Lee E, Suh PG, Choi EJ, Sun Kang S. The Na(+)/H(+) exchanger regulatory factor 2 mediates phosphorylation of serum- and glucocorticoid-induced protein kinase 1 by 3-phosphoinositide-dependent protein kinase 1. Biochem Biophys Res Commun 2002; 298:207-15. [PMID: 12387817 DOI: 10.1016/s0006-291x(02)02428-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Na(+)/H(+) exchanger regulatory factor 2 (NHERF2/TKA-1/E3KARP) contains two PSD-95/Dlg/ZO-1 (PDZ) domains which interact with the PDZ docking motif (X-(S/T)-X-(V/L)) of proteins to mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. One of the PDZ domains of NHERF2 interacts specifically with the DSLL, DSFL, and DTRL motifs present at the carboxy-termini of the 2-adrenergic receptor, the platelet-derived growth factor receptor, and the cystic fibrosis transmembrane conductance regulator, respectively. Serum- and glucocorticoid-induced protein kinase 1 (SGK1) also carries a putative PDZ-binding motif (D-S-F-L) at its carboxy tail, implicated in the specific interaction with NHERF2. There is a 3-phosphoinositide-dependent protein kinase 1 (PDK1) interacting fragment (PIF) in the tail of NHERF2. Using pull-down assays and co-transfection experiments, we demonstrated that the DSFL tail of SGK1 interacts with the first PDZ domain of NHERF2 and the PIF of NHERF2 binds to the PIF-binding pocket of PDK1 to form an SGK1-NHERF2-PDK1 complex. Formation of the protein complex promoted the phosphorylation and activation of SGK1 by PDK1. Thus, it was suggested that NHERF2 mediates the activation and phosphorylation of SGK1 by PDK1 through its first PDZ domain and PIF motif, as a novel SGK1 activation mechanism.
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Affiliation(s)
- Jaesun Chun
- School of Science Education, Chungbuk National University, Gaeshin-dong, Heungdok-gu, Chongju 361-763, Republic of Korea
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41
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Crochemore C, Michaelidis TM, Fischer D, Loeffler JP, Almeida OFX. Enhancement of p53 activity and inhibition of neural cell proliferation by glucocorticoid receptor activation. FASEB J 2002; 16:761-70. [PMID: 12039857 DOI: 10.1096/fj.01-0577com] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In analyzing the molecular mechanisms underlying glucocorticoid-induced apoptosis in neural cells, we observed that dexamethasone, by activating glucocorticoid receptors, causes arrest of HT-22 cells in the G1 phase of the cell cycle; upon withdrawal of the agonist, cells resume proliferation. Our investigations revealed that glucocorticoid treatment, although having no effects on endogenous p53 protein stability, induces rapid translocation of p53 to the nucleus and enhances its transcriptional activity. Consistently, transfection studies with p53-responsive promoters revealed a substantial stimulation of the trans-activation potential of exogenous p53 by dexamethasone. Cells arrested in G1 failed to show signs of apoptosis even after overexpression of p53. Although dexamethasone induced transcription of the proapoptotic gene bax, there was no increase of Bax protein levels. We conclude that glucocorticoid receptor-induced neural cell cycle arrest is associated with an increase in nuclear translocation and transcriptional activity of p53, and suggest that potentiation of p53 may serve as a brake on cell proliferation and may prime cells for differentiation or death induced by other signals.
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42
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43
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Abstract
Serum- and glucocorticoid-induced protein kinase 1 (SGK1) was identified in 1993 as an immediate early gene whose mRNA levels increase dramatically within 30 minutes when cells are exposed to serum or glucocorticoids, or both. Subsequently, many other agonists, acting through a variety of signal transduction pathways, have been shown to induce SGK1 gene transcription in cells and tissues. SGK1 is a member of the "AGC" subfamily, which includes protein kinases A, G, and C, and its catalytic domain is most similar to protein kinase B (PKB). Like PKB, SGK1 is activated by phosphorylation in response to signals that stimulate phosphatidylinositol 3-kinase, and this is mediated by 3-phosphoinositide-dependent protein kinase 1 (PDK1) and another protein kinase that has yet to be identified. Thus, SGK1 is remarkable in being activated at both the transcriptional and posttranslational levels by a huge number of extracellular signals. In contrast, little is known about the transcriptional regulation of the two closely related isoforms SGK2 and SGK3, although they can be activated by phosphorylation. The substrate specificity of SGK isoforms superficially resembles that of PKB in that serine and threonine residues lying in Arg-Xaa-Arg-Xaa-Xaa-Ser/Thr sequences (where Xaa is a variable amino acid) are phosphorylated. However, although they may have some substrates in common, evidence is emerging that SGK1 and PKB phosphorylate distinct proteins and have different functions in vivo. In particular, SGK1 plays an important role in activating certain potassium, sodium, and chloride channels, suggesting an involvement in the regulation of processes such as cell survival, neuronal excitability, and renal sodium excretion. Moreover, sustained high levels of SGK1 protein and activity may contribute to conditions such as hypertension and diabetic nephropathy. This raises the possibility that specific inhibitors of SGK1 may have therapeutic potential for the treatment of several diseases.
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Affiliation(s)
- F Lang
- Department of Physiology, University of Tubingen, Germany.
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44
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Salvador LM, Park Y, Cottom J, Maizels ET, Jones JC, Schillace RV, Carr DW, Cheung P, Allis CD, Jameson JL, Hunzicker-Dunn M. Follicle-stimulating hormone stimulates protein kinase A-mediated histone H3 phosphorylation and acetylation leading to select gene activation in ovarian granulosa cells. J Biol Chem 2001; 276:40146-55. [PMID: 11498542 DOI: 10.1074/jbc.m106710200] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We examined the phosphorylation and acetylation of histone H3 in ovarian granulosa cells stimulated to differentiate by follicle-stimulating hormone (FSH). We found that protein kinase A (PKA) mediates H3 phosphorylation on serine 10, based on inhibition exclusively by PKA inhibitors. FSH-stimulated H3 phosphorylation in granulosa cells is not downstream of mitogen-activated protein kinase/extracellular signal-regulated kinase, ribosomal S6 kinase-2, mitogen- and stress-activated protein kinase-1, p38 MAPK, phosphatidylinositol-3 kinase, or protein kinase C. Transcriptional activation-associated H3 phosphorylation on serine 10 and acetylation of lysine 14 leads to activation of serum glucocorticoid kinase, inhibin alpha, and c-fos genes. We propose that phosphorylation of histone H3 on serine 10 by PKA in coordination with acetylation of H3 on lysine 14 results in reorganization of the promoters of select FSH responsive genes into a more accessible configuration for activation. The unique role of PKA as the physiological histone H3 kinase is consistent with the central role of PKA in initiating granulosa cell differentiation.
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Affiliation(s)
- L M Salvador
- Department of Cell and Molecular Biology, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Medical School, Chicago, IL 60611, USA
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Dean DA, Urban G, Aragon IV, Swingle M, Miller B, Rusconi S, Bueno M, Dean NM, Honkanen RE. Serine/threonine protein phosphatase 5 (PP5) participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling. BMC Cell Biol 2001; 2:6. [PMID: 11389770 PMCID: PMC32197 DOI: 10.1186/1471-2121-2-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2000] [Accepted: 05/17/2001] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND In most cells glucocorticoid receptors (GR) reside predominantly in the cytoplasm. Upon hormone binding, the GR translocates into the nucleus, where the hormone-activated GR-complex regulates the transcription of GR-responsive genes. Serine/threonine protein phosphatase type 5 (PP5) associates with the GR-heat-shock protein-90 complex, and the suppression of PP5 expression with ISIS 15534 stimulates the activity of GR-responsive reporter plasmids, without affecting the binding of hormone to the GR. RESULTS To further characterize the mechanism by which PP5 affects GR-induced gene expression, we employed immunofluorescence microscopy to track the movement of a GR-green fluorescent fusion protein (GR-GFP) that retained hormone binding, nuclear translocation activity and specific DNA binding activity, but is incapable of transactivation. In the absence of glucocorticoids, GR-GFP localized mainly in the cytoplasm. Treatment with dexamethasone results in the efficient translocation of GR-GFPs into the nucleus. The nuclear accumulation of GR-GFP, without the addition of glucocorticoids, was also observed when the expression of PP5 was suppressed by treatment with ISIS 15534. In contrast, ISIS 15534 treatment had no apparent effect on calcium induced nuclear translocation of NFAT-GFP. CONCLUSION These studies suggest that PP5 participates in the regulation of glucocorticoid receptor nucleocytoplasmic shuttling, and that the GR-induced transcriptional activity observed when the expression of PP5 is suppressed by treatment with ISIS 15534 results from the nuclear accumulation of GR in a form that is capable of binding DNA yet still requires agonist to elicit maximal transcriptional activation.
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Affiliation(s)
- David A Dean
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Gudrun Urban
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688 USA
| | - Ileana V Aragon
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688 USA
| | - Mark Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688 USA
| | - Beth Miller
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688 USA
| | - Sandro Rusconi
- Institut de Biochimie, University of Fribourg, Perolles, CH-1700 Fribourg, Switzerland
| | - Manuel Bueno
- Institut de Biochimie, University of Fribourg, Perolles, CH-1700 Fribourg, Switzerland
| | - Nicholas M Dean
- Department of Pharmacology, ISIS Pharmaceuticals, Carlsbad, California 92008 USA
| | - Richard E Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688 USA
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Lee E, Lein ES, Firestone GL. Tissue-specific expression of the transcriptionally regulated serum and glucocorticoid-inducible protein kinase (Sgk) during mouse embryogenesis. Mech Dev 2001; 103:177-81. [PMID: 11335130 DOI: 10.1016/s0925-4773(01)00351-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In situ hybridization of mouse embryo whole mounts and sagittal sections revealed a tissue- and stage-specific expression pattern of the transcriptionally regulated serum and glucocorticoid-inducible protein kinase (sgk) during embryogenesis. Sgk expression is first observed at embryonic day 8.5 (E8.5) in the decidua and yolk sac, and then during developmental stages E9.5 through E12.5 this kinase is highly localized in the heart chamber, otic vesicle, blood vessels surrounding the somites, and lung buds. At the later stages of mouse embryogenesis, E13.5 through E16.5, sgk expression becomes highly concentrated in brain (choroid plexus), distal epithelium and the terminal bronchi/bronchioles, adrenal gland, liver, thymus and intestines, remains high in heart tissue, and is expressed at a low level in the other embryonic tissues.
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Affiliation(s)
- E Lee
- Department of Molecular and Cell Biology and The Cancer Research Laboratory, University of California at Berkeley, Berkeley, CA 94720-3200, USA
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Abstract
BACKGROUND The ERK MAP kinase pathway plays a pivotal role in growth factor-induced gene expression. However, genes whose expression is induced by the ERK pathway are not fully defined. RESULTS We have identified SGK (serum- and glucocorticoid-inducible kinase) as an ERK-inducible gene by the subtractive screening of Raf-inducible genes. SGK is known to be similar in primary structure to AKT/PKB, PKC and PKA. Treatment of quiescent NIH-3T3 cells with FGF, PDGF or TPA, which induced the sustained activation of ERKs, resulted in the strong induction of SGK, whereas treatment with EGF, which induced the transient activation of ERKs, did not induce a strong expression of SGK. The induction of SGK was blocked by pre-treatment with a specific MEK inhibitor U0126, and expression of constitutively active MEK was able to induce SGK. Treatment with cycloheximide or vanadate prolonged the increased expression of SGK by FGF, concomitant with a more prolonged activation of ERKs. CONCLUSION Growth factor-induced activation of the ERK MAP kinase pathway is necessary and sufficient for the induction of SGK.
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Affiliation(s)
- H Mizuno
- Department of Biophysics, Graduate School of Science, and Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Bell LM, Leong ML, Kim B, Wang E, Park J, Hemmings BA, Firestone GL. Hyperosmotic stress stimulates promoter activity and regulates cellular utilization of the serum- and glucocorticoid-inducible protein kinase (Sgk) by a p38 MAPK-dependent pathway. J Biol Chem 2000; 275:25262-72. [PMID: 10842172 DOI: 10.1074/jbc.m002076200] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have established that the serum- and glucocorticoid-inducible protein kinase (Sgk) is a new component of the hyperosmotic stress response. Treatment of NMuMg mammary epithelial cells with the organic osmolyte, sorbitol, caused the stable accumulation of Sgk transcripts and protein after an approximately 4-h lag. Transient transfection of a series of sgk-CAT reporter plasmids containing either 5' deletions or continuous 6-base pair substitutions identified a hyperosmotic stress-regulated element that is GC-rich and is necessary for the sorbitol stimulation of sgk gene promoter activity. Gel shift analysis identified four major DNA-protein complexes in the hyperosmotic stress-regulated element that, by competition with excess consensus wild type and mutant oligonucleotides and by antibody supershifts, contains the Sp1 transcription factor. Several lines of evidence suggest that the p38 MAPK signaling pathway mediates the hyperosmotic stress stimulation of sgk gene expression. Treatment with pharmacological inhibitors of p38 MAPK or with a dominant negative form of MKK3, an upstream regulator of p38 MAPK, significantly reduced or ablated the sorbitol induction of sgk promoter activity or protein production. Using an in vitro peptide transphosphorylation assay, sorbitol treatment activates either endogenous or exogenous Sgk that is localized to the cytoplasmic compartment. Thus, we propose that the stimulated expression of enzymatically active Sgk after sorbitol treatment is a newly defined component of the p38 MAPK-mediated response to hyperosmotic stress.
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MESH Headings
- Animals
- Blotting, Northern
- Blotting, Western
- Cell Line
- Chloramphenicol O-Acetyltransferase/genetics
- DNA, Complementary/metabolism
- Diuretics, Osmotic/pharmacology
- Epithelial Cells/metabolism
- Fluorescent Antibody Technique
- Gene Deletion
- Gene Library
- Genes, Reporter
- Humans
- Immediate-Early Proteins
- MAP Kinase Kinase 3
- Mammary Glands, Animal/metabolism
- Mice
- Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinases/metabolism
- Models, Biological
- Nuclear Proteins
- Osmotic Pressure
- Plasmids/metabolism
- Precipitin Tests
- Promoter Regions, Genetic
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- RNA, Messenger/metabolism
- Sorbitol/pharmacology
- Sp1 Transcription Factor/metabolism
- Time Factors
- Transcription, Genetic
- Transfection
- p38 Mitogen-Activated Protein Kinases
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Affiliation(s)
- L M Bell
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA
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Kumar JM, Brooks DP, Olson BA, Laping NJ. Sgk, a putative serine/threonine kinase, is differentially expressed in the kidney of diabetic mice and humans. J Am Soc Nephrol 1999; 10:2488-94. [PMID: 10589686 DOI: 10.1681/asn.v10122488] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Differential display PCR was used to identify alternate expression of serum glucocorticoid-regulated kinase (Sgk) mRNA in diabetes-induced renal disease. Differential expression of Sgk mRNA was identified in the kidneys of normal and obese db/db mice, a model of select aspects of human diabetic nephropathy. Sgk mRNA was selectively increased in diabetic mouse kidneys. The Sgk mRNA levels remained constant in other tissues from obese db/db mice. An increase in Sgk mRNA was also observed in the human diabetic kidney. In addition, thrombin, which may play a role in the progression of renal disease, increased Sgk message in cell culture. Because the diabetes-induced increase in Sgk was only observed in the kidney, which is particularly susceptible to diabetes-induced damage, Sgk may play a role in diabetic nephropathy.
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Affiliation(s)
- J M Kumar
- Department of Renal Pharmacology, SmithKline Beecham Pharmaceuticals, Pennsylvania, USA
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Zuo Z, Urban G, Scammell JG, Dean NM, McLean TK, Aragon I, Honkanen RE. Ser/Thr protein phosphatase type 5 (PP5) is a negative regulator of glucocorticoid receptor-mediated growth arrest. Biochemistry 1999; 38:8849-57. [PMID: 10413457 DOI: 10.1021/bi990842e] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ligand-induced glucocorticoid receptor (GR) activation has recently been linked to the inhibition of cell proliferation via the transcriptional induction of p21(WAF1/Cip1), which functions as a universal inhibitor of cyclin-dependent protein kinases. Herein, we identify a Ser/Thr protein phosphatase (PP5) that promotes cellular proliferation by inhibiting both glucocorticoid and p53-mediated signaling pathways leading to p21(WAF1/Cip1)-mediated growth arrest. The suppression of PP5 expression (1) markedly increases the association of GR with its cognate DNA-binding sequence, (2) induces GR transcriptional activity without the addition of hormone, and (3) increases dexamethasone-mediated induction of GR reporter activity to a level that is approximately 10 times greater than the maximal response obtainable in the presence of PP5. PP5 has no apparent effect on the binding of hormone to the GR, and dexamethasone-mediated growth arrest correlates with an increase in p53 phosphorylation. Comparative studies in p53-wild-type, p53-defective, and p53-deficient cell lines indicate that either (1) p53 participates in GR-mediated induction of p21(WAF1/Cip1), with the hyperphosphorylation of basal p53 induced by glucocorticoids sufficient for the propagation of an antiproliferative response when PP5 expression is inhibited, or (2) PP5 acts where p53-mediated and GR-induced signaling networks converge to regulate the transcriptional induction of p21(WAF1/Cip1). Thus, aberrant PP5 expression may have an additive effect on the development of human cancers by promoting cell proliferation via the inhibition of a GR-induced antiproliferative signaling cascade, and facilitating neoplastic transformation via the inhibition of a growth-arresting p53-mediated response that guards against genomic instability.
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Affiliation(s)
- Z Zuo
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile 36688, USA
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