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Rampazzo Morelli N, Pipella J, Thompson PJ. Establishing evidence for immune surveillance of β-cell senescence. Trends Endocrinol Metab 2024; 35:576-585. [PMID: 38307810 DOI: 10.1016/j.tem.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 02/04/2024]
Abstract
Cellular senescence is a programmed state of cell cycle arrest that involves a complex immunogenic secretome, eliciting immune surveillance and senescent cell clearance. Recent work has shown that a subpopulation of pancreatic β-cells becomes senescent in the context of diabetes; however, it is not known whether these cells are normally subject to immune surveillance. In this opinion article, we advance the hypothesis that immune surveillance of β-cells undergoing a senescence stress response normally limits their accumulation during aging and that the breakdown of these mechanisms is a driver of senescent β-cell accumulation in diabetes. Elucidation and therapeutic activation of immune surveillance mechanisms in the pancreas holds promise for the improvement of approaches to target stressed senescent β-cells in the treatment of diabetes.
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Affiliation(s)
- Nayara Rampazzo Morelli
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Jasmine Pipella
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Peter J Thompson
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.
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Xia S, Xi F, Ou K, Zhang Y, Ni H, Wang C, Wang Q. The effects of EGCG supplementation on pancreatic islet α and β cells distribution in adult male mice. J Nutr Biochem 2024; 124:109529. [PMID: 37951555 DOI: 10.1016/j.jnutbio.2023.109529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 10/23/2023] [Accepted: 11/08/2023] [Indexed: 11/14/2023]
Abstract
Tea and tea products are widely used as the most popular beverage in the world. EGCG is the most abundant bioactive tea polyphenol in green tea, which has positive effects on the prevention and treatment of diabetes. However, the impact of EGCG exposure on glucose homeostasis and islets in adult mice have not been reported. In this study, we studied glucose homeostasis and the morphological and molecular changes of pancreatic islet α and β cells in adult male mice after 60 d of exposure to 1 and 10 mg/kg/day EGCG by drinking water. Glucose homeostasis was not affected in both EGCG groups. The expression of pancreatic duodenal homebox1 (Pdx1) in β cells was upregulated, which might be related to increased insulin level, β cell mass and β cell proliferation in 10 mg/kg/day EGCG group. The expression of aristaless-related homeobox (Arx) in α cells did not change significantly, which corresponded with the unchanged α-cell mass. The significant reduction of musculoaponeurotic fibrosarcoma oncogene homolog B (MafB) positive α-cells might be associated with decreased glucagon level in both EGCG groups. These results suggest that EGCG supplementation dose-dependent increases β cell mass of adult mice and affects the levels of serum insulin and glucagon. Our results show that regular tea drinking in healthy people may have the possibility of preventing diabetes.
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Affiliation(s)
- Siyu Xia
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Feifei Xi
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Kunlin Ou
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Ying Zhang
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Huizhen Ni
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Chonggang Wang
- School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Qin Wang
- School of Life Sciences, Xiamen University, Xiamen, PR China.
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Cha J, Aguayo-Mazzucato C, Thompson PJ. Pancreatic β-cell senescence in diabetes: mechanisms, markers and therapies. Front Endocrinol (Lausanne) 2023; 14:1212716. [PMID: 37720527 PMCID: PMC10501801 DOI: 10.3389/fendo.2023.1212716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 08/15/2023] [Indexed: 09/19/2023] Open
Abstract
Cellular senescence is a response to a wide variety of stressors, including DNA damage, oncogene activation and physiologic aging, and pathologically accelerated senescence contributes to human disease, including diabetes mellitus. Indeed, recent work in this field has demonstrated a role for pancreatic β-cell senescence in the pathogenesis of Type 1 Diabetes, Type 2 Diabetes and monogenic diabetes. Small molecule or genetic targeting of senescent β-cells has shown promise as a novel therapeutic approach for preventing and treating diabetes. Despite these advances, major questions remain around the molecular mechanisms driving senescence in the β-cell, identification of molecular markers that distinguish senescent from non-senescent β-cell subpopulations, and translation of proof-of-concept therapies into novel treatments for diabetes in humans. Here, we summarize the current state of the field of β-cell senescence, highlighting insights from mouse models as well as studies on human islets and β-cells. We identify markers that have been used to detect β-cell senescence to unify future research efforts in this field. We discuss emerging concepts of the natural history of senescence in β-cells, heterogeneity of senescent β-cells subpopulations, role of sex differences in senescent responses, and the consequences of senescence on integrated islet function and microenvironment. As a young and developing field, there remain many open research questions which need to be addressed to move senescence-targeted approaches towards clinical investigation.
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Affiliation(s)
- Jeeyeon Cha
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, United States
| | | | - Peter J. Thompson
- Diabetes Research Envisioned and Accomplished in Manitoba Theme, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
- Department of Physiology & Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
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Brawerman G, Pipella J, Thompson PJ. DNA damage to β cells in culture recapitulates features of senescent β cells that accumulate in type 1 diabetes. Mol Metab 2022; 62:101524. [PMID: 35660116 PMCID: PMC9213768 DOI: 10.1016/j.molmet.2022.101524] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/24/2022] [Accepted: 05/31/2022] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Type 1 Diabetes (T1D) is characterized by progressive loss of insulin-producing pancreatic β cells as a result of autoimmune destruction. In addition to β cell death, recent work has shown that subpopulations of β cells acquire dysfunction during T1D. We previously reported that β cells undergoing a DNA damage response (DDR) and senescence accumulate during the pathogenesis of T1D. However, the question of how senescence develops in β cells has not been investigated. METHODS Here, we tested the hypothesis that unrepaired DNA damage in the context of genetic susceptibility triggers β cell senescence using culture models including the mouse NIT1 β cell line derived from the T1D-susceptible nonobese diabetic (NOD) strain, human donor islets and EndoC β cells. DNA damage was chemically induced using etoposide or bleomycin and cells or islets were analyzed by a combination of molecular assays for senescence phenotypes including Western blotting, qRT-PCR, Luminex assays, flow cytometry and histochemical staining. RNA-seq was carried out to profile global transcriptomic changes in human islets undergoing DDR and senescence. Insulin ELISAs were used to quantify glucose-stimulated insulin secretion from chemically-induced senescent human islets, EndoC β cells and mouse β cell lines in culture. RESULTS Sub-lethal DNA damage in NIT1 cells led to several classical hallmarks of senescence including sustained DDR activation, growth arrest, enlarged flattened morphology and a senescence-associated secretory phenotype (SASP) resembling what occurs in primary β cells during T1D in NOD mice. These phenotypes differed between NIT1 cells and the MIN6 β cell line derived from a non-T1D susceptible mouse strain. RNA-seq analysis of DNA damage-induced senescence in human islets from two different donors revealed a p53 transcriptional program and upregulation of prosurvival and SASP genes, with inter-donor variability in this response. Inter-donor variability in human islets was also apparent in the extent of persistent DDR activation and SASP at the protein level. Notably, chemically induced DNA damage also led to DDR activation and senescent phenotypes in EndoC-βH5 human β cells, confirming that this response can occur directly in a human β cell line. Finally, DNA damage led to different effects on glucose-stimulated insulin secretion in mouse β cell lines as compared with human islets and EndoC β cells. CONCLUSIONS Taken together, these findings suggest that some of the phenotypes of senescent β cells that accumulate during the development of T1D in the NOD mouse and humans can be modeled by chemically induced DNA damage to mouse β cell lines, human islets and EndoC β cells in culture. The differences between β cells from different mouse strains and different human islet donors and EndoC β cells highlights species differences and the role for genetic background in modifying the β cell response to DNA damage and its effects on insulin secretion. These culture models will be useful tools to understand some of the mechanisms of β cell senescence in T1D.
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Affiliation(s)
- Gabriel Brawerman
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada; Children's Hospital Research Institute of Manitoba, 715 McDermot ave, Winnipeg, MB R3E 3P4, Canada
| | - Jasmine Pipella
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada; Children's Hospital Research Institute of Manitoba, 715 McDermot ave, Winnipeg, MB R3E 3P4, Canada
| | - Peter J Thompson
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada; Children's Hospital Research Institute of Manitoba, 715 McDermot ave, Winnipeg, MB R3E 3P4, Canada.
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Huerta Guevara AP, McGowan SJ, Kazantzis M, Stallons TR, Sano T, Mulder NL, Jurdzinski A, van Dijk TH, Eggen BJL, Jonker JW, Niedernhofer LJ, Kruit JK. Increased insulin sensitivity and diminished pancreatic beta-cell function in DNA repair deficient Ercc1 d/- mice. Metabolism 2021; 117:154711. [PMID: 33493548 PMCID: PMC8625516 DOI: 10.1016/j.metabol.2021.154711] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/03/2021] [Accepted: 01/20/2021] [Indexed: 01/06/2023]
Abstract
BACKGROUND Type 2 diabetes (T2DM) is an age-associated disease characterized by hyperglycemia due to insulin resistance and decreased beta-cell function. DNA damage accumulation has been associated with T2DM, but whether DNA damage plays a role in the pathogenesis of the disease is unclear. Here, we used mice deficient for the DNA excision-repair gene Ercc1 to study the impact of persistent endogenous DNA damage accumulation on energy metabolism, glucose homeostasis and beta-cell function. METHODS ERCC1-XPF is an endonuclease required for multiple DNA repair pathways and reduced expression of ERCC1-XPF causes accelerated accumulation of unrepaired endogenous DNA damage and accelerated aging in humans and mice. In this study, energy metabolism, glucose metabolism, beta-cell function and insulin sensitivity were studied in Ercc1d/- mice, which model a human progeroid syndrome. RESULTS Ercc1d/- mice displayed suppression of the somatotropic axis and altered energy metabolism. Insulin sensitivity was increased, whereas, plasma insulin levels were decreased in Ercc1d/- mice. Fasting induced hypoglycemia in Ercc1d/- mice, which was the result of increased glucose disposal. Ercc1d/- mice exhibit a significantly reduced beta-cell area, even compared to control mice of similar weight. Glucose-stimulated insulin secretion in vivo was decreased in Ercc1d/- mice. Islets isolated from Ercc1d/- mice showed increased DNA damage markers, decreased glucose-stimulated insulin secretion and increased susceptibility to apoptosis. CONCLUSION Spontaneous DNA damage accumulation triggers an adaptive response resulting in improved insulin sensitivity. Loss of DNA repair, however, does negatively impacts beta-cell survival and function in Ercc1d/- mice.
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Affiliation(s)
- Ana P Huerta Guevara
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Sara J McGowan
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St., Minneapolis, MN 55455, USA; Department of Metabolism and Aging, Scripps Research Institute, Jupiter, FL 33458, USA
| | | | | | - Tokio Sano
- Department of Metabolism and Aging, Scripps Research Institute, Jupiter, FL 33458, USA
| | - Niels L Mulder
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Angelika Jurdzinski
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Theo H van Dijk
- Laboratory Medicine, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Bart J L Eggen
- Department of Biomedical Sciences of Cells & Systems, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Johan W Jonker
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Laura J Niedernhofer
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St., Minneapolis, MN 55455, USA; Department of Metabolism and Aging, Scripps Research Institute, Jupiter, FL 33458, USA
| | - Janine K Kruit
- Section of Molecular Metabolism and Nutrition, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands.
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Fang L, Zhang S, Ou K, Zuo Z, Yu A, Wang C. Exposure to Aroclor 1254 differentially affects the survival of pancreatic β-cells and α-cells in the male mice and the potential reason. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 188:109875. [PMID: 31706244 DOI: 10.1016/j.ecoenv.2019.109875] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/21/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
Previous works showed that chronic exposure to Aroclor 1254 disrupted glucose homeostasis and induced insulin resistance in male mice. To further observe the different effects of Aroclor 1254 exposure on the pancreatic α-cells and β-cells, male mice were exposed to Aroclor 1254 (0, 0.5, 5, 50, 500 μg/kg) for 60 days, the pancreas was performed a histological examination. The results showed that the percentage of apoptosis cell (indicated by TUNEL assay) was increased in both α-cells and β-cells, as the Aroclor 1254 dose was increased; the proliferation (indicated by PCNA expression) rate of β-cells was elevated while that of α-cells was not affected, resulting in an increased β-cell mass and a decreased α-cell mass in a dose-depend manner. The number of Pdx-1 positive β-cells was significantly increased whereas that of Arx positive α-cells was markedly decreased, indicating an enhanced β-cell neogenesis and a weakened α-cell neogenesis. The drastically reduction of serum testosterone levels in all the treatments suggested an anti-androgenic potency of Aroclor 1254. The up-regulation of estrogen receptors (ERα and ERβ) and androgen receptor in β-cells might be responsible for the increased β-cell mass and neogenesis.
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Affiliation(s)
- Lu Fang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Shiqi Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Kunlin Ou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Zhenghong Zuo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China
| | - Ang Yu
- Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, Xiamen University, Xiamen, PR China.
| | - Chonggang Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, PR China.
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Li N, Liu F, Yang P, Xiong F, Yu Q, Li J, Zhou Z, Zhang S, Wang CY. Aging and stress induced β cell senescence and its implication in diabetes development. Aging (Albany NY) 2019; 11:9947-9959. [PMID: 31721726 PMCID: PMC6874445 DOI: 10.18632/aging.102432] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 10/28/2019] [Indexed: 01/10/2023]
Abstract
Cellular senescence is a well-established defensive mechanism for tumor suppression, and is also proposed to play a crucial role in embryonic development, wound repair, aging and age-related diseases. Senescent cell is characterized by the marked morphological changes and active metabolism along with a distinctive senescence associated secretion phenotype (SASP). Cellular senescence is triggered by multiple endogenous and exogenous stressors, which collectively induce three types of senescence. It is believed that senescence represents a programmed phenomenon to facilitate β cell functional maturation and, therefore, senescence has been suggested to be involved in β cell regeneration, insulin secretion and diabetes development. Nevertheless, despite past extensive studies, the exact impact of senescence on β cell viability, regeneration and functionality, and its relevance to the development of diabetes are yet to be fully addressed. In this review, we will summarize the recent progress in β cell senescence, through which we intend to spark more instructive discussion and perspective with regard to the mechanisms underlying β cell senescence and their links to the pathogenesis of diabetes and the development of therapeutic strategies.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Furong Liu
- Department of Dermatology, The People's Hospital of Shishou City, Shishou, Hubei, China
| | - Ping Yang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Xiong
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qilin Yu
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinxiu Li
- Shenzhen Third People's Hospital, Longgang District, Shenzhen, Guangdong, China
| | - Zhiguang Zhou
- Diabetes Center, The Second Xiangya Hospital, Institute of Metabolism and Endocrinology, Central South University, Changsha, China
| | - Shu Zhang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cong-Yi Wang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Xiong Z, Li X, Yang Q. PTTG has a Dual Role of Promotion-Inhibition in the Development of Pituitary Adenomas. Protein Pept Lett 2019; 26:800-818. [PMID: 37020362 DOI: 10.2174/0929866526666190722145449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 11/22/2022]
Abstract
Pituitary Tumor Transforming Gene (PTTG) of human is known as a checkpoint gene in the middle and late stages of mitosis, and is also a proto-oncogene that promotes cell cycle progression. In the nucleus, PTTG works as securin in controlling the mid-term segregation of sister chromatids. Overexpression of PTTG, entering the nucleus with the help of PBF in pituitary adenomas, participates in the regulation of cell cycle, interferes with DNA repair, induces genetic instability, transactivates FGF-2 and VEGF and promotes angiogenesis and tumor invasion. Simultaneously, overexpression of PTTG induces tumor cell senescence through the DNA damage pathway, making pituitary adenoma possessing the potential self-limiting ability. To elucidate the mechanism of PTTG in the regulation of pituitary adenomas, we focus on both the positive and negative function of PTTG and find out key factors interacted with PTTG in pituitary adenomas. Furthermore, we discuss other possible mechanisms correlate with PTTG in pituitary adenoma initiation and development and the potential value of PTTG in clinical treatment.
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Affiliation(s)
- Zujian Xiong
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Xuejun Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Qi Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
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Read ML, Modasia B, Fletcher A, Thompson RJ, Brookes K, Rae PC, Nieto HR, Poole VL, Roberts S, Campbell MJ, Boelaert K, Turnell AS, Smith VE, Mehanna H, McCabe CJ. PTTG and PBF Functionally Interact with p53 and Predict Overall Survival in Head and Neck Cancer. Cancer Res 2018; 78:5863-5876. [PMID: 30154144 DOI: 10.1158/0008-5472.can-18-0855] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/05/2018] [Accepted: 08/21/2018] [Indexed: 12/12/2022]
Abstract
Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and poses a significant health burden due to its rising incidence. Although the proto-oncogene pituitary tumor-transforming gene 1 (PTTG) predicts poor patient outcome, its mechanisms of action are incompletely understood. We show here that the protein PBF modulates PTTG function, is overexpressed in HNSCC tumors, and correlates with significantly reduced survival. Lentiviral shRNA attenuation of PTTG or PBF expression in HNSCC cells with either wild-type or mutant p53, and with and without HPV infection, led to dysregulated expression of p53 target genes involved in DNA repair and apoptosis. Mechanistically, PTTG and PBF affected each other's interaction with p53 and cooperated to reduce p53 protein stability in HNSCC cells independently of HPV. Depletion of either PTTG or PBF significantly repressed cellular migration and invasion and impaired colony formation in HNSCC cells, implicating both proto-oncogenes in basic mechanisms of tumorigenesis. Patients with HNSCC with high tumoral PBF and PTTG had the poorest overall survival, which reflects a marked impairment of p53-dependent signaling.Significance: These findings reveal a complex and novel interrelationship between the expression and function of PTTG, PBF, and p53 in human HNSCC that significantly influences patient outcome. Cancer Res; 78(20); 5863-76. ©2018 AACR.
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Affiliation(s)
- Martin L Read
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom.
| | - Bhavika Modasia
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Alice Fletcher
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca J Thompson
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Katie Brookes
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Peter C Rae
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Hannah R Nieto
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Vikki L Poole
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Sally Roberts
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Moray J Campbell
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Kristien Boelaert
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Andrew S Turnell
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Vicki E Smith
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Hisham Mehanna
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Christopher J McCabe
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom.
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10
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Chen NC, Partridge AT, Tuzer F, Cohen J, Nacarelli T, Navas-Martín S, Sell C, Torres C, Martín-García J. Induction of a Senescence-Like Phenotype in Cultured Human Fetal Microglia During HIV-1 Infection. J Gerontol A Biol Sci Med Sci 2018; 73:1187-1196. [PMID: 29415134 PMCID: PMC6093403 DOI: 10.1093/gerona/gly022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/31/2018] [Indexed: 12/22/2022] Open
Abstract
HIV-1 causes premature aging in chronically infected patients. Despite effective anti-retroviral therapy, around 50% of patients suffer HIV-associated neurocognitive disorders (HAND), which likely potentiate aging-associated neurocognitive decline. Microglia support productive HIV-1 infection in the brain. Elevated markers of cellular senescence, including p53 and p21, have been detected in brain tissues from patients with HAND, but the potential for microglia senescence during HIV-1 infection has not been investigated. We hypothesized that HIV-1 can induce senescence in microglia. Primary human fetal microglia were exposed to single-round infectious HIV-1 pseudotypes or controls, and examined for markers of senescence. Post-infection, microglia had significantly elevated: senescence-associated β-galactosidase activity, p21 levels, and production of cytokines such as IL-6 and IL-8, potentially indicative of a senescence-associated secretory phenotype. We also found increased detection of p53-binding protein foci in microglia nuclei post-infection. Additionally, we examined mitochondrial reactive oxygen species (ROS) and respiration, and found significantly increased mitochondrial ROS levels and decreased ATP-linked respiration during HIV-1 infection. Supernatant transfer from infected cultures to naïve microglia resulted in elevated p21 and caveolin-1 levels, and IL-8 production. Finally, nucleoside treatment reduced senescence markers induction in microglia. Overall, HIV-1 induces a senescence-like phenotype in human microglia, which could play a role in HAND.
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Affiliation(s)
- Natalie C Chen
- Department of Microbiology and Immunology, Philadelphia, Pennsylvania
- MD/PhD Program, Philadelphia, Pennsylvania
- Molecular and Cell Biology and Genetics Graduate Program, Philadelphia, Pennsylvania
| | - Andrea T Partridge
- Department of Microbiology and Immunology, Philadelphia, Pennsylvania
- Microbiology and Immunology Graduate Program, Philadelphia, Pennsylvania
| | - Ferit Tuzer
- Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania
| | - Justin Cohen
- Molecular and Cell Biology and Genetics Graduate Program, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania
| | - Timothy Nacarelli
- Molecular and Cell Biology and Genetics Graduate Program, Philadelphia, Pennsylvania
- Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania
| | - Sonia Navas-Martín
- Department of Microbiology and Immunology, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Christian Sell
- Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania
| | - Claudio Torres
- Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania
| | - Julio Martín-García
- Department of Microbiology and Immunology, Philadelphia, Pennsylvania
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
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Yanai H, Fraifeld VE. The role of cellular senescence in aging through the prism of Koch-like criteria. Ageing Res Rev 2018; 41:18-33. [PMID: 29106993 DOI: 10.1016/j.arr.2017.10.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/11/2017] [Accepted: 10/23/2017] [Indexed: 12/13/2022]
Abstract
Since Hayflick's discovery of cellular senescence (CS), a great volume of knowledge in the field has been accumulated and intensively discussed. Here, we attempted to organize the evidence "for" and "against" the hypothesized causal role of CS in aging. For that purpose, we utilized robust Koch-like logical criteria, based on the assumption that some quantitative relationships between the accumulation of senescent cells and aging rate should exist. If so, it could be expected that (i) the "CS load" would be greater in the premature aging phenotype and lesser in longevity phenotype; (ii) CS would promote age-related diseases, and (iii) the interventions that modulate the levels of senescent cells should also modulate health/lifespan. The analysis shows that CS can be considered a causal factor of aging and an important player in various age-related diseases, though its contribution may greatly vary across species. While the relative impact of senescent cells to aging could overall be rather limited and their elimination is hardly expected to be the "fountain of youth", the potential benefits of the senolytic strategy seems a promising option in combating age-related diseases and extending healthspan.
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12
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Elevated PTTG and PBF predicts poor patient outcome and modulates DNA damage response genes in thyroid cancer. Oncogene 2017; 36:5296-5308. [PMID: 28504713 PMCID: PMC5563453 DOI: 10.1038/onc.2017.154] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 04/06/2017] [Accepted: 04/17/2017] [Indexed: 01/15/2023]
Abstract
The proto-oncogene PTTG and its binding partner PBF have been widely studied in multiple cancer types, particularly thyroid and colorectal, but their combined role in tumourigenesis is uncharacterised. Here, we show for the first time that together PTTG and PBF significantly modulate DNA damage response (DDR) genes, including p53 target genes, required to maintain genomic integrity in thyroid cells. Critically, DDR genes were extensively repressed in primary thyrocytes from a bitransgenic murine model (Bi-Tg) of thyroid-specific PBF and PTTG overexpression. Irradiation exposure to amplify p53 levels further induced significant repression of DDR genes in Bi-Tg thyrocytes (P=2.4 × 10-4) compared with either PBF- (P=1.5 × 10-3) or PTTG-expressing thyrocytes (P=NS). Consistent with this, genetic instability was greatest in Bi-Tg thyrocytes with a mean genetic instability (GI) index of 35.8±2.6%, as well as significant induction of gross chromosomal aberrations in thyroidal TPC-1 cells following overexpression of PBF and PTTG. We extended our findings to human thyroid cancer using TCGA data sets (n=322) and found striking correlations with PBF and PTTG expression in well-characterised DDR gene panel RNA-seq data. In addition, genetic associations and transient transfection identified PBF as a downstream target of the receptor tyrosine kinase-BRAF signalling pathway, emphasising a role for PBF as a novel component in a pathway well described to drive neoplastic growth. We also showed that overall survival (P=1.91 × 10-5) and disease-free survival (P=4.9 × 10-5) was poorer for TCGA patients with elevated tumoural PBF/PTTG expression and mutationally activated BRAF. Together our findings indicate that PBF and PTTG have a critical role in promoting thyroid cancer that is predictive of poorer patient outcome.
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13
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Chen NC, Partridge AT, Sell C, Torres C, Martín-García J. Fate of microglia during HIV-1 infection: From activation to senescence? Glia 2016; 65:431-446. [PMID: 27888531 DOI: 10.1002/glia.23081] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 09/12/2016] [Accepted: 09/20/2016] [Indexed: 12/14/2022]
Abstract
Microglia support productive human immunodeficiency virus type 1 (HIV-1) infection and disturbed microglial function could contribute to the development of HIV-associated neurocognitive disorders (HAND). Better understanding of how HIV-1 infection and viral protein exposure modulate microglial function during the course of infection could lead to the identification of novel therapeutic targets for both the eradication of HIV-1 reservoir and treatment of neurocognitive deficits. This review first describes microglial origins and function in the normal central nervous system (CNS), and the changes that occur during aging. We then critically discuss how HIV-1 infection and exposure to viral proteins such as Tat and gp120 affect various aspects of microglial homeostasis including activation, cellular metabolism and cell cycle regulation, through pathways implicated in cellular stress responses including p38 mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB). We thus propose that the functions of human microglia evolve during both healthy and pathological aging. Aging-associated dysfunction of microglia comprises phenotypes resembling cellular senescence, which could contribute to cognitive impairments observed in various neurodegenerative diseases. In addition, microglia seems to develop characteristics that could be related to cellular senescence post-HIV-1 infection and after exposure to HIV-1 viral proteins. However, despite its potential role as a component of HAND and likely other neurocognitive disorders, microglia senescence has not been well characterized and should be the focus of future studies, which could have high translational relevance. GLIA 2017;65:431-446.
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Affiliation(s)
- Natalie C Chen
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,MD/PhD Program, Drexel University College of Medicine, Philadelphia, Pennsylvania.,Molecular and Cell Biology and Genetics Graduate Program, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Andrea T Partridge
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,Microbiology and Immunology Graduate Program, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Christian Sell
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Claudio Torres
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Julio Martín-García
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania.,Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania
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14
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Pan X, Jiang L, Zhong L, Geng C, Jia L, Liu S, Guan H, Yang G, Yao X, Piao F, Sun X. Arsenic induces apoptosis by the lysosomal-mitochondrial pathway in INS-1 cells. ENVIRONMENTAL TOXICOLOGY 2016; 31:133-41. [PMID: 25077447 DOI: 10.1002/tox.22027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 07/06/2014] [Accepted: 07/13/2014] [Indexed: 05/02/2023]
Abstract
Recently, long term arsenic exposure was considered to be associated with an increased risk of diabetes mellitus. While a relation of cause-and-effect between apoptosis of pancreatic β-cells and arsenic exposure, the precise mechanisms of these events remains unclear. The aim of this study was to explore arsenic-induced pancreatic β-cell apoptosis and the mechanisms of through the possible link between lysosomal and the mitochondrial apoptotic pathway. After exposure to 10 μM of arsenic, the reactive oxygen species (ROS) level was significantly increased at 12 h, while the mitochondrial membrane potential was reduced at 24 h and the lysosomal membrane integrity was disrupted at 48 h. A significant increase in protein expression for cytochrome c was also observed using Western blot analysis after exposure to arsenic for 48 h. To further demonstrate that arsenic reduced the lysosomal membrane integrity, cells pretreated with NH4 Cl and exposed to arsenic harbored a lower fluorescence increase than cells that were only exposed to arsenic. In addition, apoptosis was mesured using Hoechst 33342/PI dual staining by microscopy and annexin V-FITC/propidium iodide dual staining by flow cytometry. The results show an increased uptake of the arsenic dose and the cells changed from dark blue to light blue, karyopyknosis, nuclear chromatin condensation, side set or fracture, and a correlation was found between the number of apoptotic cells and arsenic dose. The result of present study suggest that arsenic may induce pancreatic β-cell apoptosis through activation of the lysosome-mitochondrial pathway.
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Affiliation(s)
- Xiao Pan
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Liping Jiang
- Natural Products Engineering Technology Research Center, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Laifu Zhong
- Natural Products Engineering Technology Research Center, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Chengyan Geng
- Natural Products Engineering Technology Research Center, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Li Jia
- College of Laboratory Medicine, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Shuang Liu
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Huai Guan
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Guang Yang
- Natural Products Engineering Technology Research Center, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Xiaofeng Yao
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Fengyuan Piao
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
| | - Xiance Sun
- Department of Ocuupational and Environmental Health, College of Public Health, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
- Natural Products Engineering Technology Research Center, Dalian Medical University, No. 9 Western Section, Lvshun South Street, Dalian, 116044, People's Republic of China
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15
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Campbell JE, Ussher JR, Mulvihill EE, Kolic J, Baggio LL, Cao X, Liu Y, Lamont BJ, Morii T, Streutker CJ, Tamarina N, Philipson LH, Wrana JL, MacDonald PE, Drucker DJ. TCF1 links GIPR signaling to the control of beta cell function and survival. Nat Med 2015; 22:84-90. [DOI: 10.1038/nm.3997] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/26/2015] [Indexed: 12/18/2022]
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Abstract
Recent discoveries are redefining our view of cellular senescence as a trigger of tissue remodelling that acts during normal embryonic development and upon tissue damage. To achieve this, senescent cells arrest their own proliferation, recruit phagocytic immune cells and promote tissue renewal. This sequence of events - senescence, followed by clearance and then regeneration - may not be efficiently completed in aged tissues or in pathological contexts, thereby resulting in the accumulation of senescent cells. Increasing evidence indicates that both pro-senescent therapies and antisenescent therapies can be beneficial. In cancer and during active tissue repair, pro-senescent therapies contribute to minimize the damage by limiting proliferation and fibrosis, respectively. Conversely, antisenescent therapies may help to eliminate accumulated senescent cells and to recover tissue function.
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Arumugam R, Fleenor D, Freemark M. Knockdown of prolactin receptors in a pancreatic beta cell line: effects on DNA synthesis, apoptosis, and gene expression. Endocrine 2014; 46:568-76. [PMID: 24114406 PMCID: PMC3984618 DOI: 10.1007/s12020-013-0073-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 09/24/2013] [Indexed: 12/18/2022]
Abstract
Prolactin (PRL) and placental lactogen stimulate beta cell replication and insulin production in vitro and in vivo. The molecular mechanisms by which lactogens promote beta cell expansion are unclear. We treated rat insulinoma cells with a PRL receptor (PRLR) siRNA to determine if PRLR signaling is required for beta cell DNA synthesis and cell survival and to identify beta cell cycle genes whose expression depends upon lactogen action. Effects of PRLR knockdown were compared with those of PRL treatment. PRLR knockdown (-80 %) reduced DNA synthesis, increased apoptosis, and inhibited expression of cyclins D2 and B2, IRS-2, Tph1, and the anti-apoptotic protein PTTG1; p21 and BCL6 mRNAs increased. Conversely, PRL treatment increased DNA synthesis, reduced apoptosis, and enhanced expression of A, B and D2 cyclins, CDK1, IRS-2, FoxM1, BCLxL, and PTTG1; BCL6 declined. PRLR signaling is required for DNA synthesis and survival of rat insulinoma cells. The effects of lactogens are mediated by down-regulation of cell cycle inhibitors (BCL6, p21) and induction of A, B, and D2 cyclins, IRS-2, Tph1, FoxM1, and the anti-apoptotic proteins BCLxL and PTTG1.
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Affiliation(s)
- Ramamani Arumugam
- Departments of Pediatrics, Duke University Medical Center, Durham NC 27710 USA
| | - Don Fleenor
- Departments of Pediatrics, Duke University Medical Center, Durham NC 27710 USA
| | - Michael Freemark
- Departments of Pediatrics, Duke University Medical Center, Durham NC 27710 USA
- Cell Biology, Duke University Medical Center, Durham NC 27710 USA
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18
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Monahan P, Himes AD, Parfieniuk A, Raetzman LT. p21, an important mediator of quiescence during pituitary tumor formation, is dispensable for normal pituitary development during embryogenesis. Mech Dev 2011; 128:640-52. [PMID: 22154697 DOI: 10.1016/j.mod.2011.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/14/2011] [Accepted: 11/23/2011] [Indexed: 12/25/2022]
Abstract
A delicate balance between proliferation and differentiation must be maintained in the developing pituitary to ensure the formation of the appropriate number of hormone producing cells. In the adult, proliferation is actively restrained to prevent tumor formation. The cyclin dependent kinase inhibitors (CDKIs) of the CIP/KIP family, p21, p27 and p57, mediate cell cycle inhibition. Although p21 is induced in the pituitary upon loss of Notch signaling or initiation of tumor formation to halt cell cycle progression, its role in normal pituitary organogenesis has not been explored. In wildtype pituitaries, expression of p21 is limited to a subset of cells embryonically as well as during the postnatal proliferative phase. Mice lacking p21 do not have altered cell proliferation during early embryogenesis, but do show a slight delay in separation of proliferating progenitors from the oral ectoderm. By embryonic day 16.5, p21 mutants have an alteration in the spatial distribution of proliferating pituitary progenitors, however there is no overall change in proliferation. At postnatal day 21, there appears to be no change in proliferation, as assessed by cells expressing Ki67 protein. However, p21 mutant pituitaries have significantly less mRNA of Myc and the cyclins Ccnb1, Ccnd1, Ccnd2 and Ccne1 than wildtype pituitaries. Interestingly, unlike the redundant role in cell cycle inhibition uncovered in p27/p57 double mutants, the pituitary of p21/p27 double mutants has a similar proliferation profile to p27 single mutants at the time points examined. Taken together, these studies demonstrate that unlike p27 or p57, p21 does not play a major role in control of progenitor proliferation in the developing pituitary. However, p21 may be required to maintain normal levels of cell cycle components.
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Affiliation(s)
- Pamela Monahan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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19
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Yu R, Dhall D, Nissen NN, Zhou C, Ren SG. Pancreatic neuroendocrine tumors in glucagon receptor-deficient mice. PLoS One 2011; 6:e23397. [PMID: 21853126 PMCID: PMC3154424 DOI: 10.1371/journal.pone.0023397] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 07/14/2011] [Indexed: 02/06/2023] Open
Abstract
Inhibition of glucagon signaling causes hyperglucagonemia and pancreatic α cell hyperplasia in mice. We have recently demonstrated that a patient with an inactivating glucagon receptor mutation (P86S) also exhibits hyperglucagonemia and pancreatic α cell hyperplasia but further develops pancreatic neuroendocrine tumors (PNETs). To test the hypothesis that defective glucagon signaling causes PNETs, we studied the pancreata of mice deficient in glucagon receptor (Gcgr−/−) from 2 to 12 months, using WT and heterozygous mice as controls. At 2–3 months, Gcgr−/− mice exhibited normal islet morphology but the islets were mostly composed of α cells. At 5–7 months, dysplastic islets were evident in Gcgr−/− mice but absent in WT or heterozygous controls. At 10–12 months, gross PNETs (≥1 mm) were detected in most Gcgr−/− pancreata and micro-PNETs (<1 mm) were found in all (n = 14), whereas the islet morphology remained normal and no PNETs were found in any WT (n = 10) or heterozygous (n = 25) pancreata. Most PNETs in Gcgr−/− mice were glucagonomas, but some were non-functioning. No tumors predominantly expressed insulin, pancreatic polypeptide, or somatostatin, although some harbored focal aggregates of tumor cells expressing one of those hormones. The PNETs in Gcgr−/− mice were well differentiated and occasionally metastasized to the liver. Menin expression was aberrant in most dysplatic islets and PNETs. Vascular endothelial growth factor (VEGF) was overexpressed in PNET cells and its receptor Flk-1 was found in the abundant blood vessels or blood islands inside the tumors. We conclude that defective glucagon signaling causes PNETs in the Gcgr−/− mice, which may be used as a model of human PNETs. Our results further suggest that completely inhibiting glucagon signaling may not be a safe approach to treat diabetes.
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Affiliation(s)
- Run Yu
- Division of Endocrinology, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
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Lubka-Pathak M, Shah AA, Gallozzi M, Müller M, Zimmermann U, Löwenheim H, Pfister M, Knipper M, Blin N, Schimmang T. Altered expression of securin (Pttg1) and serpina3n in the auditory system of hearing-impaired Tff3-deficient mice. Cell Mol Life Sci 2011; 68:2739-49. [PMID: 21076990 PMCID: PMC11114927 DOI: 10.1007/s00018-010-0586-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 10/22/2010] [Accepted: 10/26/2010] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Tff3 peptide exerts important functions in cytoprotection and restitution of the gastrointestinal (GI) tract epithelia. Moreover, its presence in the rodent inner ear and involvement in the hearing process was demonstrated recently. However, its role in the auditory system still remains elusive. Our previous results showed a deterioration of hearing with age in Tff3-deficient animals. RESULTS Present detailed analysis of auditory brain stem response (ABR) measurements and immunohistochemical study of selected functional proteins indicated a normal function and phenotype of the cochlea in Tff3 mutants. However, a microarray-based screening of tissue derived from the auditory central nervous system revealed an alteration of securin (Pttg1) and serpina3n expression between wild-type and Tff3 knock-out animals. This was confirmed by qRT-PCR, immunostaining and western blots. CONCLUSIONS We found highly down-regulated Pttg1 and up-regulated serpina3n expression as a consequence of genetically deleting Tff3 in mice, indicating a potential role of these factors during the development of presbyacusis.
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Affiliation(s)
- M. Lubka-Pathak
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - A. A. Shah
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - M. Gallozzi
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
| | - M. Müller
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - U. Zimmermann
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - H. Löwenheim
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Pfister
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - M. Knipper
- University Hospital of Otorhinolaryngology, Tübingen Hearing Research Centre (THRC), Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - N. Blin
- Division of Molecular Genetics, Institute of Human Genetics, University of Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany
| | - T. Schimmang
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, C/Sanz y Forés 3, 47003 Valladolid, Spain
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Abstract
The pituitary tumor-transforming gene (PTTG1) encodes a multifunctional protein (PTTG) that is overexpressed in numerous tumours, including pituitary, thyroid, breast and ovarian carcinomas. PTTG induces cellular transformation in vitro and tumourigenesis in vivo, and several mechanisms by which PTTG contributes to tumourigenesis have been investigated. Also known as the human securin, PTTG is involved in cell cycle regulation, controlling the segregation of sister chromatids during mitosis. This review outlines current information regarding PTTG structure, expression, regulation and function in the pathogenesis of neoplasia. Recent progress concerning the use of PTTG as a prognostic marker or therapeutic target will be considered. In addition, the PTTG binding factor (PBF), identified through its interaction with PTTG, has also been established as a proto-oncogene that is upregulated in several cancers. Current knowledge regarding PBF is outlined and its role both independently and alongside PTTG in endocrine and related cancers is discussed.
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Chen WS, Yu YC, Lee YJ, Chen JH, Hsu HY, Chiu SJ. Depletion of securin induces senescence after irradiation and enhances radiosensitivity in human cancer cells regardless of functional p53 expression. Int J Radiat Oncol Biol Phys 2010; 77:566-74. [PMID: 20457353 DOI: 10.1016/j.ijrobp.2009.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 10/16/2009] [Accepted: 12/10/2009] [Indexed: 12/12/2022]
Abstract
PURPOSE Radiotherapy is one of the best choices for cancer treatment. However, various tumor cells exhibit resistance to irradiation-induced apoptosis. The development of new strategies to trigger cancer cell death besides apoptosis is necessary. This study investigated the role of securin in radiation-induced apoptosis and senescence in human cancer cells. METHODS AND MATERIALS Cell survival was determined using clonogenic assays. Western blot analysis was used to analyze levels of securin, caspase-3, PARP, p53, p21, Rb, gamma-H2AX, and phospho-Chk2. Senescent cells were analyzed using a beta-galactosidase staining assay. A securin-expressed vector (pcDNA-securin) was stably transfected into securin-null HCT116 cells. Securin gene knockdown was performed by small interfering RNA and small hairpin RNA in HCT116 and MDA-MB-231 cells, respectively. RESULTS Radiation was found to induce apoptosis in securin wild type HCT116 cells but induced senescence in securin-null cells. Restoration of securin reduced senescence and increased cell survival in securin-null HCT116 cells after irradiation. Radiation-induced gamma-H2AX and Chk2 phosphorylation were induced transiently in securin-wild-type cells but exhibited sustained activation in securin-null cells. Securin gene knockdown switches irradiation-induced apoptosis to senescence in both HCT116 p53-null and MDA-MB-231 cells. CONCLUSIONS Our results demonstrated that the level of securin expression plays a determining role in the radiosensitivity and fate of cells. Depletion of securin impairs DNA repair after irradiation, increasing DNA damage and promoting senescence in the residual surviving cells regardless of functional p53 expression. The knockdown of securin may contribute to a novel radiotherapy protocol for the treatment of human cancer cells that are resistant to irradiation.
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Affiliation(s)
- Wen-Shu Chen
- Department of Life Science, Tzu Chi University, Hualien, Taiwan
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23
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Tavana O, Puebla-Osorio N, Sang M, Zhu C. Absence of p53-dependent apoptosis combined with nonhomologous end-joining deficiency leads to a severe diabetic phenotype in mice. Diabetes 2010; 59:135-42. [PMID: 19833883 PMCID: PMC2797914 DOI: 10.2337/db09-0792] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Regulation of pancreatic beta-cell mass is essential to preserve sufficient insulin levels for the maintenance of glucose homeostasis. Previously, we reported that DNA double-strand breaks (DSBs) resulting from nonhomologous end-joining (NHEJ) deficiency induce apoptosis and, when combined with p53 deficiency, progressed rapidly into lymphomagenesis in mice. Combination of NHEJ deficiency with a hypomorphic mutation, p53R172P, leads to the abrogation of apoptosis, upregulation of p21, and senescence in precursor lymphocytes. This was sufficient to prevent tumorigenesis. However, these mutant mice succumb to severe diabetes and die at an early age. The aim of this study was to determine the pathogenesis of diabetes in these mutant mice. RESEARCH DESIGN AND METHODS We analyzed the morphology of the pancreatic islets and the function, proliferation rate, and senescence of beta-cells. We also profiled DNA damage and p53 and p21 expression in the pancreas. RESULTS NHEJ-p53R172P mutant mice succumb to diabetes at 3-5 months of age. These mice show a progressive decrease in pancreatic islet mass that is independent of apoptosis and innate immunity. We observed an accumulation of DNA damage, accompanied with increased levels of p53 and p21, a significant decrease in beta-cell proliferation, and cellular senescence in the mutant pancreatic islets. CONCLUSIONS Combined DSBs with an absence of p53-dependent apoptosis activate p53-dependent senescence, which leads to a diminished beta-cell self-replication, massive depletion of the pancreatic islets, and severe diabetes. This is a model that connects impaired DNA repair and accumulative DNA damage, a common phenotype in aging individuals, to the onset of diabetes.
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Affiliation(s)
- Omid Tavana
- Department of Immunology, University of Texas, M.D. Anderson Cancer Center, Houston, Texas
- University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
| | - Nahum Puebla-Osorio
- Department of Immunology, University of Texas, M.D. Anderson Cancer Center, Houston, Texas
| | - Mei Sang
- Department of Immunology, University of Texas, M.D. Anderson Cancer Center, Houston, Texas
| | - Chengming Zhu
- Department of Immunology, University of Texas, M.D. Anderson Cancer Center, Houston, Texas
- University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
- Corresponding author: Chengming Zhu,
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