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Khan S, Mosvi SN, Vohra S, Poddar NK. Implication of calcium supplementations in health and diseases with special focus on colorectal cancer. Crit Rev Clin Lab Sci 2024; 61:496-509. [PMID: 38456354 DOI: 10.1080/10408363.2024.2322565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/31/2024] [Accepted: 02/20/2024] [Indexed: 03/09/2024]
Abstract
Calcium is a fundamental and integrative element and helps to ensure optimal health by regulating various physiological and pathological processes. While there is substantiated evidence confirming the beneficial effects of calcium in the treatment, management, and prevention of various health conditions, including cancer, conflicting studies are imperative to acknowledge the potential negative role of calcium supplementation. The studies on calcium supplementation showed that a specific dose can help in the maintenance of good human health, and in the control of different types of diseases, including cancer. Calcium alone and when combined with vitamin D, emerges as a promising therapeutic option for efficiently managing cancer growth, when used with chemotherapy. Combination therapy is considered a more effective approach for treating advanced types of colorectal cancer. Nevertheless, several challenges drastically influence the treatment of cancer, such as individual discrepancy, drug resistance, and stage of cancer, among others. Henceforth, novel preventive, reliable therapeutic modalities are essential to control and reduce the incidence and mortality of colorectal cancer (CRC). The calcium-sensing receptor (CaSR) plays a pivotal role in calcium homeostasis, metabolism, and regulation of oncogenesis. Numerous studies have underscored the potential of CaSR, a G protein-coupled receptor, as a potential biomarker and target for colorectal cancer prevention and treatment. The multifaceted involvement of CaSR in anti-inflammatory and anti-carcinogenic processes paves the way for its utilization in the diagnosis and management of colorectal cancer. The current review highlights the important role of supplemental calcium in overall health and disease, along with the exploration of intricate mechanisms of CaSR pathways in the management and prevention of colorectal cancer.
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Affiliation(s)
- Shahanavaj Khan
- Department of Medical Lab Technology, Indian Institute of Health and Technology (IIHT), Deoband, Saharanpur, India
- Department of Health Sciences, Novel Global Community Educational Foundation, Sydney, Australia
| | - S Needa Mosvi
- Department of Biosciences, Shri Ram Group of College (SRGC), Muzaffarnagar, India
| | - Saeed Vohra
- Department of Anatomy and Physiology, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
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Lee J, Shin A, Choi JY, Kang D, Lee JK. Adherence to the Recommended Intake of Calcium and Colorectal Cancer Risk in the HEXA Study. Cancer Res Treat 2020; 53:140-147. [PMID: 32854492 PMCID: PMC7812010 DOI: 10.4143/crt.2020.480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/24/2020] [Indexed: 12/31/2022] Open
Abstract
Purpose Dietary calcium intake has been suggested to be protective against the development of colorectal cancer. The mean dietary calcium intake of Koreans is 490 mg/day, which is far below the recommended calcium intake of 700-800 mg/day. In this study, we explored the relationship between dietary calcium intake and colorectal cancer development in Koreans with relatively low calcium intake compared with individuals in Western countries. Materials and Methods The Health Examinees Study, a large-scale genomic community-based prospective cohort study, was designed to identify the general characteristics of major chronic diseases in Koreans. A total of 119,501 participants aged 40-69 years recruited between 2004 and 2013 were included in this analysis. The calcium intake level was categorized using the Dietary Reference Intakes for Koreans (KDRIs). The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) and the corresponding 95% confidence intervals (CIs) for colorectal cancer risk, adjusting for potential confounders. Results In the multivariable-adjusted model, compared with the group that consumed less than the recommended amount of calcium, the group that consumed more than the recommended intake of calcium showed a significant reduction in the risk of colorectal cancer in women. (HR, 0.54; 95% CI, 0.31 to 0.95). Among men, however, no significant association was observed between dietary calcium intake and colorectal cancer risk (HR, 0.89; 95% CI, 0.54 to 1.45). Conclusion Korean women who adhere to the recommended intake of calcium showed a reduced risk of colorectal cancer.
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Affiliation(s)
- Jeeyoo Lee
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Aesun Shin
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University, Seoul, Korea
| | - Ji-Yeob Choi
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University, Seoul, Korea.,Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea
| | - Daehee Kang
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea
| | - Jong-Koo Lee
- JW LEE Center for Global Medicine, Seoul National University College of Medicine, Seoul, Korea.,Department of Family Medicine, Seoul National University College of Medicine, Seoul, Korea.,Seoul Center for Infectious Disease Control, Seoul, Korea
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3
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Yang W, Ma Y, Smith-Warner S, Song M, Wu K, Wang M, Chan AT, Ogino S, Fuchs CS, Poylin V, Ng K, Meyerhardt JA, Giovannucci EL, Zhang X. Calcium Intake and Survival after Colorectal Cancer Diagnosis. Clin Cancer Res 2018; 25:1980-1988. [PMID: 30545821 DOI: 10.1158/1078-0432.ccr-18-2965] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/24/2018] [Accepted: 12/10/2018] [Indexed: 01/05/2023]
Abstract
PURPOSE Although evidence suggests an inverse association between calcium intake and colorectal cancer incidence, the influence of calcium on survival after colorectal cancer diagnosis remains unclear.Experimental Design: We prospectively assessed the association of postdiagnostic calcium intake with colorectal cancer-specific and overall mortality among 1,660 nonmetastatic colorectal cancer patients within the Nurses' Health Study and the Health Professionals Follow-up Study. Patients completed a validated food frequency questionnaire between 6 months and 4 years after diagnosis and were followed up for death. Multivariable hazard ratios (HRs) and 95% confidence intervals (95% CI) were calculated using Cox proportional hazards regression. RESULTS Comparing the highest with the lowest quartile intake of postdiagnostic total calcium, the multivariable HRs were 0.56 (95% CI, 0.32-0.96; P trend = 0.04) for colorectal cancer-specific mortality and 0.80 (95% CI, 0.59-1.09; P trend = 0.11) for all-cause mortality. Postdiagnostic supplemental calcium intake was also inversely associated with colorectal cancer-specific mortality (HR, 0.67; 95% CI, 0.42-1.06; P trend = 0.047) and all-cause mortality (HR, 0.71; 95% CI, 0.54-0.94; P trend = 0.008), although these inverse associations were primarily observed in women. In addition, calcium from diet or dairy sources was associated with lower risk in men. CONCLUSIONS Higher calcium intake after the diagnosis may be associated with a lower risk of death among patients with colorectal cancer. If confirmed, these findings may provide support for the nutritional recommendations of maintaining sufficient calcium intake among colorectal cancer survivors.
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Affiliation(s)
- Wanshui Yang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Yanan Ma
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning, P.R. China
| | - Stephanie Smith-Warner
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Mingyang Song
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.,Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts
| | - Kana Wu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Molin Wang
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Andrew T Chan
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Shuji Ogino
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts.,Program in MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Charles S Fuchs
- Department of Medical Oncology, Yale Cancer Center, New Haven, Connecticut.,Department of Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Medical Oncology, Smilow Cancer Hospital, New Haven, Connecticut
| | - Vitaliy Poylin
- Department of Surgery, Division of Colon and Rectal Surgery, Beth Israel Deaconess Medical Center in Boston, Massachusetts
| | - Kimmie Ng
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
| | - Jeffrey A Meyerhardt
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts
| | - Edward L Giovannucci
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Xuehong Zhang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
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Guo Y, Yang X, He J, Liu J, Yang S, Dong H. Important roles of the Ca 2+-sensing receptor in vascular health and disease. Life Sci 2018; 209:217-227. [PMID: 30098342 DOI: 10.1016/j.lfs.2018.08.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 02/07/2023]
Abstract
Ca2+-sensing receptor (CaSR), a member of G protein-coupled receptor family, is widely expressed in the vascular system, including perivascular neurons, vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). When stimulated, CaSR can further increase the cytosolic Ca2+ concentration ([Ca2+]cyt) in two ways: intracellular Ca2+ release from endo/sarcoplasmic reticulum (ER/SR) and extracellular Ca2+ entry through Ca2+-permeable cation channels. In endothelium, increased Ca2+ subsequently activate nitric oxide synthase (NOS) and intermediate conductance Ca2+-activated K+ channels (IKCa), resulting in vasodilation through NOS-mediated NO release or membrane hyperpolarization. In VSMCs, CaSR-induced intracellular Ca2+ increase causes blood vessel constriction. CaSR activation predominantly induces vasorelaxation of whole vascular tissues through VECs-dependent mechanisms; however, CaSR-induced Ca2+ signaling in VSMCs may play a braking role in CaSR-mediated vasorelaxation. Emerging evidence reveals the importance of CaSR in the regulation of vascular tone and blood pressure. Here, we summarized recent advances in CaSR-mediated vascular reaction and the underlying mechanisms in different species, including humans. In addition, several studies have demonstrated that CaSR dysfunction may be associated with some fatal vascular diseases, such as pulmonary arterial hypertension, primary hypertension, diabetes, acute myocardial infarction and vascular calcification. With the advance of studies on CaSR in vascular health and disease, it is expected positive modulators or negative modulators of CaSR used for the treatment of specific diseases may be promising therapeutic options for the prevention and/or treatment of vascular diseases.
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Affiliation(s)
- Yanjun Guo
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jialin He
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jingjing Liu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Shiming Yang
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China.
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Yang W, Liu L, Masugi Y, Qian ZR, Nishihara R, Keum N, Wu K, Smith-Warner SA, Ma Y, Nowak JA, Momen-Heravi F, Zhang L, Bowden M, Morikawa T, da Silva A, Wang M, Chan AT, Fuchs CS, Meyerhardt JA, Ng K, Giovannucci E, Ogino S, Zhang X. Calcium intake and risk of colorectal cancer according to expression status of calcium-sensing receptor (CASR). Gut 2018; 67:1475-1483. [PMID: 28676564 PMCID: PMC5754263 DOI: 10.1136/gutjnl-2017-314163] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/08/2017] [Accepted: 05/15/2017] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Although evidence suggests an inverse association between calcium intake and the risk of colorectal cancer, the mechanisms remain unclear. The calcium-sensing receptor (CASR) is expressed abundantly in normal colonic epithelium and may influence carcinogenesis. We hypothesized that calcium intake might be associated with lower risk of CASR-positive, but not CASR-negative, colorectal cancer. DESIGN We assessed tumour CASR protein expression using immunohistochemistry in 779 incident colon and rectal cancer cases that developed among 136 249 individuals in the Nurses' Health Study and Health Professionals Follow-Up Study. Duplication method Cox proportional hazards regression analysis was used to assess associations of calcium intake with incidence of colorectal adenocarcinoma subtypes by CASR status. RESULTS Total calcium intake was inversely associated with the risk of developing colorectal cancer (ptrend=0.01, comparing ≥1200 vs <600 mg/day: multivariable HR=0.75, 95% CI 0.60 to 0.95). For the same comparison, higher total calcium intake was associated with a lower risk of CASR-positive tumours (ptrend=0.003, multivariable HR=0.67, 95% CI 0.51 to 0.86) but not with CASR-negative tumours (ptrend=0.67, multivariable HR=1.15, 95% CI 0.75 to 1.78; pheterogeneity=0.06 between the CASR subtypes). The stronger inverse associations of calcium intake with CASR-positive but not CASR-negative tumours generally appeared consistent regardless of sex, tumour location and source of calcium. CONCLUSIONS Our molecular pathological epidemiology data suggest a causal relationship between higher calcium intake and lower colorectal cancer risk, and a potential role of CASR in mediating antineoplastic effect of calcium.
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Affiliation(s)
- Wanshui Yang
- Department of Social Science and Public Health, School of Basic Medical Science, Jiujiang University, Jiujiang, Jiangxi, P.R. China
| | - Li Liu
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Epidemiology and Biostatistics, and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Yohei Masugi
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Zhi Rong Qian
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Reiko Nishihara
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA,Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Division of MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School Boston, MA, USA
| | - NaNa Keum
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Kana Wu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Stephanie A. Smith-Warner
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Yanan Ma
- Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning, PR China
| | - Jonathan A Nowak
- Division of MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School Boston, MA, USA
| | - Fatemeh Momen-Heravi
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA,Section of Oral and Diagnostic Sciences, Division of Periodontics, Columbia University College of Dental Medicine, New York, NY, USA
| | - Libin Zhang
- Institute for Community Inclusion, University of Massachusetts Boston, MA, USA
| | - Michaela Bowden
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Teppei Morikawa
- Department of Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Annacarolina da Silva
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Molin Wang
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Andrew T. Chan
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA,Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA,Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Charles S. Fuchs
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA,Yale Cancer Center, New Haven, CT, USA,Department of Medicine, Yale School of Medicine, New Haven, CT, USA,Smilow Cancer Hospital, New Haven, CT, USA
| | - Jeffrey A. Meyerhardt
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Kimmie Ng
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Edward Giovannucci
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Shuji Ogino
- Department of Oncologic Pathology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA,Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA,Division of MPE Molecular Pathological Epidemiology, Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School Boston, MA, USA
| | - Xuehong Zhang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
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Lin LY, Yeh YH, Hung GY, Lin CH, Hwang PP, Horng JL. Role of Calcium-Sensing Receptor in Mechanotransducer-Channel-Mediated Ca 2+ Influx in Hair Cells of Zebrafish Larvae. Front Physiol 2018; 9:649. [PMID: 29899708 PMCID: PMC5988855 DOI: 10.3389/fphys.2018.00649] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 05/14/2018] [Indexed: 01/16/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is an extracellular Ca2+ sensor that plays a critical role in maintaining Ca2+ homeostasis in several organs, including the parathyroid gland and kidneys. In this study, through in situ hybridization, the expression of CaSR mRNA was found in the neuromasts of zebrafish larvae. Immunohistochemistry further demonstrated that the CaSR protein was present in neuromast hair cell stereocilia and basolateral membranes. Based on the expression and subcellular localization of the CaSR in hair cells, we hypothesized that the CaSR is expressed in zebrafish lateral-line hair cells to regulate mechanotransducer (MET)-channel-mediated Ca2+ entry. Using the scanning ion-selective electrode technique, MET-channel-mediated Ca2+ influx at the stereocilia of hair cells was measured in intact larvae. Ca2+ influx was suppressed after larvae were pretreated with a CaSR activator (R-568) or high-Ca2+ (HCa) medium. Gene knockdown by using morpholino oligonucleotides decreased CaSR expression in hair cells and eliminated the effects of R-568 and HCa on Ca2+ influx. In addition, we found that treatment with R-568 attenuated neomycin-induced hair cell death. This study is the first to demonstrate that the CaSR is involved in mechanotransduction in zebrafish hair cells.
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Affiliation(s)
- Li-Yih Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ya-Hsin Yeh
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Giun-Yi Hung
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.,Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Pediatrics, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Hao Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.,Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Signaling through the extracellular calcium-sensing receptor (CaSR). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:103-42. [PMID: 22453940 DOI: 10.1007/978-94-007-2888-2_5] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The extracellular calcium ([Formula: see text])-sensing receptor (CaSR) was the first GPCR identified whose principal physiological ligand is an ion, namely extracellular Ca(2+). It maintains the near constancy of [Formula: see text] that complex organisms require to ensure normal cellular function. A wealth of information has accumulated over the past two decades about the CaSR's structure and function, its role in diseases and CaSR-based therapeutics. This review briefly describes the CaSR and key features of its structure and function, then discusses the extracellular signals modulating its activity, provides an overview of the intracellular signaling pathways that it controls, and, finally, briefly describes CaSR signaling both in tissues participating in [Formula: see text] homeostasis as well as those that do not. Factors controlling CaSR signaling include various factors affecting the expression of the CaSR gene as well as modulation of its trafficking to and from the cell surface. The dimeric cell surface CaSR, in turn, links to various heterotrimeric and small molecular weight G proteins to regulate intracellular second messengers, lipid kinases, various protein kinases, and transcription factors that are part of the machinery enabling the receptor to modulate the functions of the wide variety of cells in which it is expressed. CaSR signaling is impacted by its interactions with several binding partners in addition to signaling elements per se (i.e., G proteins), including filamin-A and caveolin-1. These latter two proteins act as scaffolds that bind signaling components and other key cellular elements (e.g., the cytoskeleton). Thus CaSR signaling likely does not take place randomly throughout the cell, but is compartmentalized and organized so as to facilitate the interaction of the receptor with its various signaling pathways.
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Kumar R, Thompson JR. The regulation of parathyroid hormone secretion and synthesis. J Am Soc Nephrol 2010; 22:216-24. [PMID: 21164021 DOI: 10.1681/asn.2010020186] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Secondary hyperparathyroidism classically appears during the course of chronic renal failure and sometimes after renal transplantation. Understanding the mechanisms by which parathyroid hormone (PTH) synthesis and secretion are normally regulated is important in devising methods to regulate overactivity and hyperplasia of the parathyroid gland after the onset of renal insufficiency. Rapid regulation of PTH secretion in response to variations in serum calcium is mediated by G-protein coupled, calcium-sensing receptors on parathyroid cells, whereas alterations in the stability of mRNA-encoding PTH by mRNA-binding proteins occur in response to prolonged changes in serum calcium. Independent of changes in intestinal calcium absorption and serum calcium, 1α,25-dihydroxyvitamin D also represses the transcription of PTH by associating with the vitamin D receptor, which heterodimerizes with retinoic acid X receptors to bind vitamin D-response elements within the PTH gene. 1α,25-Dihydroxyvitamin D additionally regulates the expression of calcium-sensing receptors to indirectly alter PTH secretion. In 2°HPT seen in renal failure, reduced concentrations of calcium-sensing and vitamin D receptors, and altered mRNA-binding protein activities within the parathyroid cell, increase PTH secretion in addition to the more widely recognized changes in serum calcium, phosphorus, and 1α,25-dihydroxyvitamin D. The treatment of secondary hyperparathyroidism by correction of serum calcium and phosphorus concentrations and the administration of vitamin D analogs and calcimimetic agents may be augmented in the future by agents that alter the stability of mRNA-encoding PTH.
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Affiliation(s)
- Rajiv Kumar
- Division of Nephrology and Hypertension, Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic and Foundation, 200 1 Street SW, Rochester, MN 55905, USA.
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Bandyopadhyay S, Tfelt-Hansen J, Chattopadhyay N. Diverse roles of extracellular calcium-sensing receptor in the central nervous system. J Neurosci Res 2010; 88:2073-82. [PMID: 20336672 DOI: 10.1002/jnr.22391] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The G-protein-coupled calcium-sensing receptor (CaSR), upon activation by Ca(2+) or other physiologically relevant polycationic molecules, performs diverse functions in the brain. The CaSR is widely expressed in the central nervous system (CNS) and is characterized by a robust increase in its expression during postnatal brain development over adult levels throughout the CNS. Developmental increases in CaSR levels in brain correlate with myelinogenesis. Indeed, neural stem cells differentiating to the oligodendrocyte lineage exhibit the highest CaSR expression compared with those differentiating to astrocytic or neuronal lineages. In adult CNS, CaSR has broad relevance in maintaining local ionic homeostasis. CaSR shares an evolutionary relationship with the metabotropic glutamate receptor and forms heteromeric complexes with the type B-aminobutyric acid receptor subunits that affects its cell surface expression, activation, signaling, and functions. In normal physiology as well as in pathologic conditions, CaSR is activated by signals arising from mineral ions, amino acids, polyamines, glutathione, and amyloid-beta in conjunction with Ca(2+) and other divalent cationic ligands. CaSR activation regulates membrane excitability of neurons and glia and affects myelination, olfactory and gustatory signal integration, axonal and dendritic growth, and gonadotrophin-releasing hormonal-neuronal migration. Insofar as the CaSR is a clinically important therapeutic target for parathyroid disorders, development of its agonists or antagonists as therapeutics for CNS disorder could be a major breakthrough.
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Affiliation(s)
- Sanghamitra Bandyopadhyay
- Developmental Toxicology, Indian Institute of Toxicology Research (Council of Scientific and Industrial Rsearch; CSIR), Lucknow, India
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10
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Smajilovic S, Tfelt-Hansen J. Novel Role of the Calcium-Sensing Receptor in Blood Pressure Modulation. Hypertension 2008; 52:994-1000. [DOI: 10.1161/hypertensionaha.108.117689] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sanela Smajilovic
- From the Laboratory of Molecular Cardiology (S.S., J.T-H.), Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (S.S., J.T-H.), Copenhagen, Denmark
| | - Jacob Tfelt-Hansen
- From the Laboratory of Molecular Cardiology (S.S., J.T-H.), Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (S.S., J.T-H.), Copenhagen, Denmark
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11
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Kapoor A, Satishchandra P, Ratnapriya R, Reddy R, Kadandale J, Shankar SK, Anand A. An idiopathic epilepsy syndrome linked to 3q13.3-q21 and missense mutations in the extracellular calcium sensing receptor gene. Ann Neurol 2008; 64:158-67. [DOI: 10.1002/ana.21428] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Maiti A, Hait NC, Beckman MJ. Extracellular Calcium-sensing Receptor Activation Induces Vitamin D Receptor Levels in Proximal Kidney HK-2G Cells by a Mechanism That Requires Phosphorylation of p38α MAPK. J Biol Chem 2008; 283:175-183. [DOI: 10.1074/jbc.m707269200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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13
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Smajilovic S, Sheykhzade M, Holmegard HN, Haunso S, Tfelt-Hansen J. Calcimimetic, AMG 073, induces relaxation on isolated rat aorta. Vascul Pharmacol 2007; 47:222-8. [PMID: 17690018 DOI: 10.1016/j.vph.2007.06.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 06/21/2007] [Indexed: 10/23/2022]
Abstract
Calcimimetics are a class of compounds that positively modulate the calcium-sensing receptor (CaR) by allosterically increasing the affinity of the receptor for extracellular Ca(2+). In this study we have investigated the effects of the clinically used calcimimetic, AMG 073, on contractility of the rat aorta by wire myography. AMG 073 elicited a concentration-dependent vasodilatation of the precontracted aorta. Inhibition of endothelium function by L-NAME and indomethacin reduced AMG 073-induced relaxation of the vessel precontracted with phenylephrine, but not with 125 mM K(+). The vasodilatory effect could be mediated by the CaR or/and a direct action on the ion channels. Intriguingly, CaR agonists, neomycin and gadolinium, did not have any effect on the contractility of the aorta. Immunohistochemical staining of the aorta with two CaR specific antibodies demonstrated the presence of the CaR protein, predominantly in endothelial and adventitial layers.
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Affiliation(s)
- Sanela Smajilovic
- Laboratory of Molecular Cardiology, Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Denmark
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14
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Bandyopadhyay S, Jeong KH, Hansen JT, Vassilev PM, Brown EM, Chattopadhyay N. Calcium-sensing receptor stimulates secretion of an interferon-γ-induced monokine (CXCL10) and monocyte chemoattractant protein-3 in immortalized GnRH neurons. J Neurosci Res 2007; 85:882-95. [PMID: 17285630 DOI: 10.1002/jnr.21177] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Biology of GnRH neurons is critically dependent on extracellular Ca(2+) (Ca(2+) (o)). We evaluated differences in gene expression patterns with low and high Ca(2+) (o) in an immortalized GnRH neuron line, GT1-7 cells. Mouse global oligonucleotide microarray was used to evaluate transcriptional differences among the genes regulated by elevated Ca(2+) (o). Our result identified two interferon-gamma (IFNgamma)-inducible chemokines, CXCL9 and CXCL10, and a beta chemokine, monocyte chemoattractant protein-3 (MCP-3/CCL7), being up-regulated in GT1-7 cells treated with high Ca(2+) (o) (3.0 mM) compared with low Ca(2+) (o) (0.5 mM). Up-regulation of these mRNAs by elevated Ca(2+) (o) was confirmed by quantitative PCR. Elevated Ca(2+) (o) stimulated secretion of CXCL10 and MCP-3 but not CXCL9 in GT1-7 cells, and this effect was mediated by an extracellular calcium-sensing receptor (CaR) as the dominant negative CaR attenuated secretion of CXCL10 and MCP-3. CXCL10 and MCP-3 were localized in mouse GnRH neurons in the preoptic hypothalamus. Suppression of K(+) channels (BK channels) with 25 nM charybdotoxin inhibited high-Ca(2+) (o)-stimulated CXCL10 release. Accordingly, CaR activation by a specific CaR agonist, NPS-467, resulted in the activation of a Ca(2+)-activated K(+) channel in these cells. CaR-mediated MCP-3 secretion involves the PI3 kinase pathway in GT1-7 cells. MCP-3 stimulated chemotaxis of astrocytes treated with transforming growth factor-beta (TGFbeta). With TGFbeta-treated astrocytes, we next observed that conditioned medium from GT1-7 cells treated with high Ca(2+) promoted chemotaxis of astrocytes, and this effect was attenuated by a neutralizing antibody to MCP-3. These results implicate CaR as an important regulator of GnRH neuron function in vivo by stimulating secretion of heretofore unsuspected cytokines, i.e., CXCL10 and MCP-3.
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Affiliation(s)
- Sanghamitra Bandyopadhyay
- Neurochemistry Laboratory, Department of Psychiatry and Genetics and Aging Research Unit, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02115, USA
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15
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Li D, Wang Z, Sun P, Jin Y, Lin DH, Hebert SC, Giebisch G, Wang WH. Inhibition of MAPK stimulates the Ca2+ -dependent big-conductance K channels in cortical collecting duct. Proc Natl Acad Sci U S A 2006; 103:19569-74. [PMID: 17151195 PMCID: PMC1748266 DOI: 10.1073/pnas.0609555104] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kidney plays a key role in maintaining potassium (K) homeostasis. K excretion is determined by the balance between K secretion and absorption in distal tubule segments such as the connecting tubule and cortical collecting duct. K secretion takes place by K entering principal cells (PC) from blood side through Na+, K+ -ATPase and being secreted into the lumen via both ROMK-like small-conductance K (SK) channels and Ca2+ -activated big-conductance K (BK) channels. K reabsorption occurs by stimulation of apical K/H-ATPase and inhibition of K recycling across the apical membrane in intercalated cells (IC). The role of ROMK channels in K secretion is well documented. However, the importance of BK channels in mediating K secretion is incompletely understood. It has been shown that their activity increases with high tubule flow rate and augmented K intake. However, BK channels have a low open probability and are mainly located in IC, which lack appropriate transporters for effective K secretion. Here we demonstrate that inhibition of ERK and P38 MAPKs stimulates BK channels in both PC and IC in the cortical collecting duct and that changes in K intake modulate their activity. Under control conditions, BK channel activity in PC was low but increased significantly by inhibition of both ERK and P38. Blocking MAPKs also increased channel open probability of BK in IC and thereby it may affect K backflux and net K absorption Thus, modulation of ERK and P38 MAPK activity is involved in controlling net K secretion in the distal nephron.
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Affiliation(s)
- Dimin Li
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Zhijian Wang
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Peng Sun
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Yan Jin
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Dao-Hong Lin
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
| | - Steven C. Hebert
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Gerhard Giebisch
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
- To whom correspondence may be addressed. E-mail:
or
| | - Wen-Hui Wang
- *Department of Pharmacology, New York Medical College, Valhalla, NY 10595; and
- To whom correspondence may be addressed. E-mail:
or
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16
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Babilonia E, Li D, Wang Z, Sun P, Lin DH, Jin Y, Wang WH. Mitogen-activated protein kinases inhibit the ROMK (Kir 1.1)-like small conductance K channels in the cortical collecting duct. J Am Soc Nephrol 2006; 17:2687-96. [PMID: 16971657 PMCID: PMC2825048 DOI: 10.1681/asn.2006050426] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
It was demonstrated previously that low dietary potassium (K) intake stimulates Src family protein tyrosine kinase (PTK) expression via a superoxide-dependent signaling. This study explored the role of mitogen-activated protein kinase (MAPK) in mediating the effect of superoxide anions on PTK expression and ROMK (Kir 1.1) channel activity. Western blot analysis demonstrated that low K intake significantly increased the phosphorylation of P38 MAPK (P38) and extracellular signal-regulated kinase (ERK) but had no effect on phosphorylation of c-JUN N-terminus kinase in renal cortex and outer medulla. The stimulatory effect of low K intake on P38 and ERK was abolished by treatment of rats with tempol. The possibility that increases in superoxide and related products that are induced by low K intake were responsible for stimulating phosphorylation of P38 and ERK also was supported by the finding that application of H(2)O(2) increased the phosphorylation of ERK and P38 in the cultured mouse collecting duct cells. Simultaneous blocking of ERK and P38 completely abolished the effect of H(2)O(2) on c-Src expression in mouse collecting duct cells. For determination of the role of P38 and ERK in the regulation of ROMK-like small-conductance K (SK) channels, the patch-clamp technique was used to study the effect of inhibiting P38 and ERK on SK channels in the cortical collecting duct from rats that were on a control K diet (1.1%) and on a K-deficient diet for 1 d. Inhibition of ERK, c-JUN N-terminus kinase, or P38 alone had no effect on SK channels. In contrast, simultaneous inhibition of P38 and ERK significantly increased channel activity. The effect of inhibiting MAPK on SK channels was not affected in the presence of herbimycin A, a PTK inhibitor, and was larger in rats that were on a K-deficient diet than in rats that were on a normal-K diet. However, the stimulatory effect of inhibiting ERK and P38 on SK was absent in the cortical collecting duct that was treated with colchicine. It is concluded that low K intake-induced increases in superoxide levels are responsible for stimulation of P38 and ERK and that MAPK inhibit the SK channels by stimulating PTK expression and via a PTK-independent mechanism.
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Affiliation(s)
- Elisa Babilonia
- Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA
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17
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Poolos NP, Bullis JB, Roth MK. Modulation of h-channels in hippocampal pyramidal neurons by p38 mitogen-activated protein kinase. J Neurosci 2006; 26:7995-8003. [PMID: 16870744 PMCID: PMC6674228 DOI: 10.1523/jneurosci.2069-06.2006] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 06/22/2006] [Accepted: 06/23/2006] [Indexed: 11/21/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated ion channels (h-channels; I(h); HCN) modulate intrinsic excitability in hippocampal and neocortical pyramidal neurons, among others. Whereas I(h) mediated by the HCN2 isoform is regulated by cAMP, there is little known about kinase modulation of I(h), especially for the HCN1 isoform predominant in pyramidal neurons. We used a computational method to identify a novel kinase modulator of h-channels, p38 mitogen-activated protein kinase (p38 MAPK). Inhibition of p38 MAPK in hippocampal pyramidal neurons caused a approximately 25 mV hyperpolarization of I(h) voltage-dependent activation. This downregulation of I(h) produced hyperpolarization of resting potential, along with increased input resistance and temporal summation of excitatory inputs. Activation of p38 MAPK caused a approximately 11 mV depolarizing shift in I(h) activation, along with depolarized resting potential, and decreased input resistance and temporal summation. Inhibition of related MAPKs, ERK1/2 (extracellular signal-related kinase 1/2) and JNK (c-Jun N-terminal kinase), produced no effect on I(h). These results show that p38 MAPK is a strong modulator of h-channel biophysical properties and may deserve additional exploration as a link between altered I(h) and pathological conditions such as epilepsy.
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Affiliation(s)
- Nicholas P Poolos
- Department of Neurology and Regional Epilepsy Center, Neurobiology and Behavior Program, University of Washington, Seattle, Washington 98104, USA.
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Chattopadhyay N. Effects of calcium-sensing receptor on the secretion of parathyroid hormone-related peptide and its impact on humoral hypercalcemia of malignancy. Am J Physiol Endocrinol Metab 2006; 290:E761-70. [PMID: 16603723 DOI: 10.1152/ajpendo.00350.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The extracellular calcium-sensing receptor (CaR) plays a key role in the defense against hypercalcemia by "sensing" extracellular calcium (Ca2+(o)) levels in the parathyroid and kidney, the key organs maintaining systemic calcium homeostasis. However, CaR function can be aberrant in certain pathophysiological states, e.g., in some types of cancers known to produce humoral hypercalcemia of malignancy (HHM) in humans and animal models in which high Ca2+(o), via the CaR, produces a homeostatically inappropriate stimulation of parathyroid hormone-related peptide (PTHrP) secretion from these tumors. Increased levels of PTHrP set a cycle in motion whereby elevated systemic levels of Ca2+(o) resulting from its increased bone-resorptive and positive renal calcium-reabsorbing effects give rise to hypercalcemia, which in turn begets worsening hypercalcemia by stimulating further release of PTHrP by the cancer cells. I review the relationship between CaR activation and PTHrP release in normal and tumor cells giving rise to HHM and/or malignant osteolysis and the actions of the receptor on key cellular events such as proliferation, angiogenesis, and apoptosis of cancer cells that will favor tumor growth and osseous metastasis. I also illustrate diverse signaling mechanisms underlying CaR-stimulated PTHrP secretion and other cellular events in tumor cells. Finally, I raise several necessary questions to demonstrate the roles of the receptor in promoting tumors and metastases that will enable consideration of the CaR as a potential antagonizing/neutralizing target for the treatment of HHM.
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Affiliation(s)
- Naibedya Chattopadhyay
- Div. of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, 221 Longwood Ave., Boston, MA 02115, USA.
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Tfelt-Hansen J, Hansen JL, Smajilovic S, Terwilliger EF, Haunso S, Sheikh SP. Calcium receptor is functionally expressed in rat neonatal ventricular cardiomyocytes. Am J Physiol Heart Circ Physiol 2006; 290:H1165-71. [PMID: 16243911 DOI: 10.1152/ajpheart.00821.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both intra- and extracellular calcium play multiple roles in the physiology and pathophysiology of cardiomyocytes, especially in stimulus-contraction coupling. The intracellular calcium level is closely controlled through the concerted actions of calcium channels, exchangers, and pumps; however, the expression and function(s) of the so-called calcium-sensing receptor (CaR) in the heart remain less well characterized. The CaR is a seven-transmembrane receptor, which, in response to noncovalent binding of extracellular calcium, activates intracellular effectors, including G proteins and extracellular signal-regulated kinases (ERK1/2). We have shown that cultured neonatal cardiomyocytes express the CaR messenger RNA and the CaR protein. Furthermore, increasing concentrations of extracellular calcium and a type II CaR activator “calcimimetic” caused inositol phosphate (IP) accumulation, downregulated tritiated thymidine incorporation, and supported ERK1/2 phosphorylation, suggesting that the CaR protein is functionally active. Interestingly, the calcimimetic induced a more rapid ERK1/2 phosphorylation than calcium and left-shifted the IP concentration-response curve for extracellular calcium, supporting the hypothesis that CaR is functionally expressed in cardiac myocytes. This notion was underscored by studies using a virus containing a dominant-negative CaR construct, because this protein blunted the calcium-induced IP response. In conclusion, we have shown that the CaR is functionally expressed in neonatal ventricular cardiomyocytes and that the receptor activates second messenger pathways, including IP and ERK, and decreases DNA synthesis. A specific calcium-sensing receptor on cardiac myocytes could play a role in regulating cardiac development, function, and homeostasis.
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Affiliation(s)
- Jacob Tfelt-Hansen
- Laboratory of Molecular Cardiology, Department of Cardiology, Copenhagen University Hospital, Rigshospitaket, Denmark.
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20
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Weston AH, Absi M, Ward DT, Ohanian J, Dodd RH, Dauban P, Petrel C, Ruat M, Edwards G. Evidence in favor of a calcium-sensing receptor in arterial endothelial cells: studies with calindol and Calhex 231. Circ Res 2005; 97:391-8. [PMID: 16037572 DOI: 10.1161/01.res.0000178787.59594.a0] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Small increases in extracellular Ca2+ dilate isolated blood vessels. In the present study, the possibility that a vascular, extracellular Ca2+-sensing receptor (CaSR) could mediate these vasodilator actions was investigated. Novel ligands that interact with the CaSR were used in microelectrode recordings from rat isolated mesenteric and porcine coronary arteries. The major findings were that (1) raising extracellular Ca2+ or adding calindol, a CaSR agonist, produced concentration-dependent hyperpolarizations of vascular myocytes, actions attenuated by Calhex 231, a negative allosteric modulator of CaSR. (2) Calindol-induced hyperpolarizations were inhibited by the intermediate conductance, Ca2+-sensitive K+ (IKCa) channel inhibitors, TRAM-34, and TRAM-39. (3) The effects of calindol were not observed in the absence of endothelium. (4) CaSR mRNA and protein were present in rat mesenteric arteries and in porcine coronary artery endothelial cells. (5) CaSR and IKCa proteins were restricted to caveolin-poor membrane fractions. We conclude that activation of vascular endothelial CaSRs opens endothelial cell IKCa channels with subsequent myocyte hyperpolarization. The endothelial cell CaSR may have a physiological role in the control of arterial blood pressure.
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Wu Z, Tandon R, Ziembicki J, Nagano J, Hujer KM, Miller RT, Huang C. Role of ceramide in Ca2+-sensing receptor-induced apoptosis. J Lipid Res 2005; 46:1396-404. [PMID: 15805541 DOI: 10.1194/jlr.m500071-jlr200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Increased extracellular Ca(2+) ([Ca(2+)](o)) can damage tissues, but the molecular mechanisms by which this occurs are poorly defined. Using HEK 293 cell lines that stably overexpress the Ca(2+)-sensing receptor (CaR), a G protein-coupled receptor, we demonstrate that activation of the CaR leads to apoptosis, which was determined by nuclear condensation, DNA fragmentation, caspase-3 activation, and increased cytosolic cytochrome c. This CaR-induced apoptotic pathway is initiated by CaR-induced accumulation of ceramide which plays an important role in inducing cell death signals by distinct G protein-independent signaling pathways. Pretreatment of wild-type CaR-expressing cells with pertussis toxin inhibited CaR-induced [(3)H]ceramide formation, c-Jun phosphorylation, and caspase-3 activation. The ceramide accumulation, c-Jun phosphorylation, and caspase-3 activation by the CaR can be abolished by sphingomyelinase and ceramide synthase inhibitors in different time frames. Cells that express a nonfunctional mutant CaR that were exposed to the same levels of [Ca(2+)](o) showed no evidence of activation of the apoptotic pathway. In conclusion, we report the involvement of the CaR in stimulating programmed cell death via a pathway involving GTP binding protein alpha subunit (Galpha(i))-dependent ceramide accumulation, activation of stress-activated protein kinase/c-Jun N-terminal kinase, c-Jun phosphorylation, caspase-3 activation, and DNA cleavage.
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Affiliation(s)
- Zhenzhen Wu
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Tfelt-Hansen J, Yano S, Bandyopadhyay S, Carroll R, Brown EM, Chattopadhyay N. Expression of pituitary tumor transforming gene (PTTG) and its binding protein in human astrocytes and astrocytoma cells: function and regulation of PTTG in U87 astrocytoma cells. Endocrinology 2004; 145:4222-31. [PMID: 15178645 DOI: 10.1210/en.2003-1661] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human securin, pituitary tumor transforming gene (PTTG), is a protooncogene. Here we report expressions of PTTG and its interacting protein, PTTG-binding factor in human astrocytic cells. PTTG expression was higher in malignant cells than in primary astrocytes, whereas PTTG-binding factor was not. Using a xenotransplantable, glioma cell line (U87), we observed that knocking down PTTG mRNA by RNA silencing inhibited serum-induced proliferation by approximately 50%. Furthermore, in U87 cells PTTG expression was up-regulated by promalignant ligands epithelial growth factor (EGF) and TGFalpha, both at the protein and mRNA levels. PTTG induction by EGF receptor (EGFR) ligands could be blocked by the specific EGFR inhibitor, AG1478. Hepatocyte growth factor (HGF) also induced PTTG but to a lesser extent than EGF. Although EGF stimulates HGF secretion in U87 cells, the effect of EGF on PTTG mRNA expression is independent of HGF as neutralizing antibody against HGF failed to abolish EGF-induced up-regulation of PTTG mRNA. PTTG mRNA was unchanged by incubating U87 cells with the promalignant growth factor TGFbeta, apoptosis inducing TNFalpha and ligands for nuclear receptors, such as retinoic acid and retinoid X receptors and peroxisome proliferator-activated receptor-gamma, known for their growth-inhibitory and apoptosis-inducing effects on gliomas. In addition, 17beta-estradiol and Ca2+, known to activate PTTG expression, did not change PTTG mRNA levels in U87 cells. In summary, we show higher PTTG expression in astrocytoma than normal astrocytes and secondly, PTTG is involved in glioma cell growth. Finally, regulation of its expression has glioma-specific features and is selectively regulated by promalignant cytokines including EGFR ligands and HGF.
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Affiliation(s)
- Jacob Tfelt-Hansen
- Division of Endocrinology, Diabetes, and Hypertension,Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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