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Martin TJ. PTH1R Actions on Bone Using the cAMP/Protein Kinase A Pathway. Front Endocrinol (Lausanne) 2022; 12:833221. [PMID: 35126319 PMCID: PMC8807523 DOI: 10.3389/fendo.2021.833221] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/24/2021] [Indexed: 12/29/2022] Open
Abstract
After the initial signaling action of parathyroid hormone (PTH) on bone was shown to be activation of adenylyl cyclase, its target was found to be cells of the osteoblast lineage, to the exclusion of osteoclasts and their precursors. This led to the view that the osteoblast lineage regulated osteoclast formation, a proposal that was established when the molecular mechanisms of osteoclast formation were discovered. This is in addition to the effect of PTH1Rv signaling throughout the osteoblast differentiation process to favour the formation of bone-forming osteoblasts. Initial signaling in the PTH target cells through cAMP and protein kinase A (PKA) activation is extremely rapid, and marked by an amplification process in which the later event, PKA activation, precedes cAMP accumulation in time and is achieved at lower concentrations. All of this is consistent with the existence of "spare receptors", as is the case with several other peptide hormones. PTH-related protein (PTHrP), that was discovered as a cancer product, shares structural similarity with PTH in the amino-terminal domain that allows the hormone, PTH, and the autocrine/paracrine agent, PTHrP, to share actions upon a common G protein coupled receptor, PTH1R, through which they activate adenylyl cyclase with equivalent potencies. Studies of ligand-receptor kinetics have revealed that the PTH/PTH1R ligand-receptor complex, after initial binding and adenylyl cyclase activation at the plasma membrane, is translocated to the endosome, where adenylyl cyclase activation persists for a further short period. This behavior of the PTH1R resembles that of a number of hormones and other agonists that undergo such endosomal translocation. It remains to be determined whether and to what extent the cellular effects through the PTH1R might be influenced when endosomal is added to plasma membrane activation.
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Affiliation(s)
- T. John Martin
- Department of Medicine, St Vincent’s Institute of Medical Research, St Vincent’s Health, University of Melbourne, Fitzroy, VIC, Australia
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Martin TJ, Sims NA, Seeman E. Physiological and Pharmacological Roles of PTH and PTHrP in Bone Using Their Shared Receptor, PTH1R. Endocr Rev 2021; 42:383-406. [PMID: 33564837 DOI: 10.1210/endrev/bnab005] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Indexed: 12/13/2022]
Abstract
Parathyroid hormone (PTH) and the paracrine factor, PTH-related protein (PTHrP), have preserved in evolution sufficient identities in their amino-terminal domains to share equivalent actions upon a common G protein-coupled receptor, PTH1R, that predominantly uses the cyclic adenosine monophosphate-protein kinase A signaling pathway. Such a relationship between a hormone and local factor poses questions about how their common receptor mediates pharmacological and physiological actions of the two. Mouse genetic studies show that PTHrP is essential for endochondral bone lengthening in the fetus and is essential for bone remodeling. In contrast, the main postnatal function of PTH is hormonal control of calcium homeostasis, with no evidence that PTHrP contributes. Pharmacologically, amino-terminal PTH and PTHrP peptides (teriparatide and abaloparatide) promote bone formation when administered by intermittent (daily) injection. This anabolic effect is remodeling-based with a lesser contribution from modeling. The apparent lesser potency of PTHrP than PTH peptides as skeletal anabolic agents could be explained by lesser bioavailability to PTH1R. By contrast, prolongation of PTH1R stimulation by excessive dosing or infusion, converts the response to a predominantly resorptive one by stimulating osteoclast formation. Physiologically, locally generated PTHrP is better equipped than the circulating hormone to regulate bone remodeling, which occurs asynchronously at widely distributed sites throughout the skeleton where it is needed to replace old or damaged bone. While it remains possible that PTH, circulating within a narrow concentration range, could contribute in some way to remodeling and modeling, its main physiological role is in regulating calcium homeostasis.
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Affiliation(s)
- T John Martin
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,The University of Melbourne, Department of Medicine at St. Vincent's Hospital, Fitzroy, Victoria, Australia
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,The University of Melbourne, Department of Medicine at St. Vincent's Hospital, Fitzroy, Victoria, Australia
| | - Ego Seeman
- The University of Melbourne, Department of Medicine at Austin Health, Heidelberg, Victoria, Australia
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Lertsuwan K, Nammultriputtar K, Nanthawuttiphan S, Tannop N, Teerapornpuntakit J, Thongbunchoo J, Charoenphandhu N. Differential effects of Fe2+ and Fe3+ on osteoblasts and the effects of 1,25(OH)2D3, deferiprone and extracellular calcium on osteoblast viability under iron-overloaded conditions. PLoS One 2020; 15:e0234009. [PMID: 32470038 PMCID: PMC7259719 DOI: 10.1371/journal.pone.0234009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/15/2020] [Indexed: 02/07/2023] Open
Abstract
One of the potential contributing factors for iron overload-induced osteoporosis is the iron toxicity on bone forming cells, osteoblasts. In this study, the comparative effects of Fe3+ and Fe2+ on osteoblast differentiation and mineralization were studied in UMR-106 osteoblast cells by using ferric ammonium citrate and ferrous ammonium sulfate as Fe3+ and Fe2+ donors, respectively. Effects of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] and iron chelator deferiprone on iron uptake ability of osteoblasts were examined, and the potential protective ability of 1,25(OH)2D3, deferiprone and extracellular calcium treatment in osteoblast cell survival under iron overload was also elucidated. The differential effects of Fe3+ and Fe2+ on reactive oxygen species (ROS) production in osteoblasts were also compared. Our results showed that both iron species suppressed alkaline phosphatase gene expression and mineralization with the stronger effects from Fe3+ than Fe2+. 1,25(OH)2D3 significantly increased the intracellular iron but minimally affected osteoblast cell survival under iron overload. Deferiprone markedly decreased intracellular iron in osteoblasts, but it could not recover iron-induced osteoblast cell death. Interestingly, extracellular calcium was able to rescue osteoblasts from iron-induced osteoblast cell death. Additionally, both iron species could induce ROS production and G0/G1 cell cycle arrest in osteoblasts with the stronger effects from Fe3+. In conclusions, Fe3+ and Fe2+ differentially compromised the osteoblast functions and viability, which can be alleviated by an increase in extracellular ionized calcium, but not 1,25(OH)2D3 or iron chelator deferiprone. This study has provided the invaluable information for therapeutic design targeting specific iron specie(s) in iron overload-induced osteoporosis. Moreover, an increase in extracellular calcium could be beneficial for this group of patients.
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Affiliation(s)
- Kornkamon Lertsuwan
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Ketsaraporn Nammultriputtar
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | - Natnicha Tannop
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Jirawan Thongbunchoo
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
- The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand
- * E-mail:
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Martin TJ, Johnson RW. Multiple actions of parathyroid hormone-related protein in breast cancer bone metastasis. Br J Pharmacol 2019; 178:1923-1935. [PMID: 31087800 DOI: 10.1111/bph.14709] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/16/2019] [Accepted: 04/23/2019] [Indexed: 12/14/2022] Open
Abstract
The sequence similarity within the amino-terminal regions of parathyroid hormone (PTH) and PTH-related protein (PTHrP) allows the two to share actions at a common site, the PTH1 receptor. A number of biological activities have been ascribed to actions of other domains within PTHrP. PTHrP production by late stage breast cancer has been shown to contribute to bone metastasis formation through promotion of osteoclast formation and bone resorption by action through PTH1 receptors. There is evidence also for a role for PTHrP early in breast cancer that is protective against tumour progression. No signalling pathway has been identified for this effect. PTHrP has also been identified as a factor promoting the emergence of breast cancer cells from dormancy in bone. In that case, PTHrP does not function through activation of PTH1 receptors, despite having very substantial effects on transcriptional activity of the breast cancer cells. This indicates actions of PTHrP that are non-canonical, that is, mediated through domains other than the amino-terminal. It is concluded that PTHrP has several distinct paracrine, autocrine, and intracrine actions in the course of breast cancer pathophysiology. Some are mediated through action at PTH1 receptors and others are controlled by other domains within PTHrP. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.
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Affiliation(s)
- T John Martin
- St Vincent's Institute of Medical Research, University of Melbourne, St Vincent's Health, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, St Vincent's Health, Melbourne, Victoria, Australia
| | - Rachelle W Johnson
- Department of Medicine, Division of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
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Martin TJ. Parathyroid Hormone-Related Protein, Its Regulation of Cartilage and Bone Development, and Role in Treating Bone Diseases. Physiol Rev 2016; 96:831-71. [DOI: 10.1152/physrev.00031.2015] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although parathyroid hormone-related protein (PTHrP) was discovered as a cancer-derived hormone, it has been revealed as an important paracrine/autocrine regulator in many tissues, where its effects are context dependent. Thus its location and action in the vasculature explained decades-long observations that injection of PTH into animals rapidly lowered blood pressure by producing vasodilatation. Its roles have been specified in development and maturity in cartilage and bone as a crucial regulator of endochondral bone formation and bone remodeling, respectively. Although it shares actions with parathyroid hormone (PTH) through the use of their common receptor, PTHR1, PTHrP has other actions mediated by regions within the molecule beyond the amino-terminal sequence that resembles PTH, including the ability to promote placental transfer of calcium from mother to fetus. A striking feature of the physiology of PTHrP is that it possesses structural features that equip it to be transported in and out of the nucleus, and makes use of a specific nuclear import mechanism to do so. Evidence from mouse genetic experiments shows that PTHrP generated locally in bone is essential for normal bone remodeling. Whereas the main physiological function of PTH is the hormonal regulation of calcium metabolism, locally generated PTHrP is the important physiological mediator of bone remodeling postnatally. Thus the use of intermittent injection of PTH as an anabolic therapy for bone appears to be a pharmacological application of the physiological function of PTHrP. There is much current interest in the possibility of developing PTHrP analogs that might enhance the therapeutic anabolic effects.
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Affiliation(s)
- T. John Martin
- St Vincent's Institute of Medical Research, Department of Medicine, University of Melbourne, St Vincent's Hospital, Melbourne, Australia
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Danks JA, Freeman AN, Martin TJ. Historical Perspective and Evolutionary Origins of Parathyroid Hormone-Related Protein. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9163-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Martin TJ. Historically significant events in the discovery of RANK/RANKL/OPG. World J Orthop 2013; 4:186-197. [PMID: 24147254 PMCID: PMC3801238 DOI: 10.5312/wjo.v4.i4.186] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/07/2013] [Accepted: 03/23/2013] [Indexed: 02/06/2023] Open
Abstract
After it was suggested 30 years ago that the osteoblast lineage controlled the formation of osteoclasts, methods were developed that established this to be the case, but the molecular controls were elusive. Over more than a decade much evidence was obtained for signaling mechanisms that regulated the production of a membrane - bound regulator of osteoclastogenesis, in the course of which intercellular communication in bone was revealed in its complexity. The discovery of regulation by tumor necrosis factor ligand and receptor families was made in the last few years of the twentieth century, leading since then to a new physiology of bone, and to exciting drug development.
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Leis HJ, Hulla W, Gruber R, Huber E, Zach D, Gleispach H, Windischhofer W. Phenotypic heterogeneity of osteoblast-like MC3T3-E1 cells: changes of bradykinin-induced prostaglandin E2 production during osteoblast maturation. J Bone Miner Res 1997; 12:541-51. [PMID: 9101365 DOI: 10.1359/jbmr.1997.12.4.541] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have examined clonal murine calvarial MC3T3-E1 cells obtained from different sources to compare their osteoblastic features (alkaline phosphatase [ALP], cyclic adenosine monophosphate [cAMP] response to parathyroid hormone, prostaglandin E2 (PGE2) and PGE1, bradykinin-induced production of PGE2). It was found that the sublines investigated showed large variation of the above-mentioned parameters, which may be attributed to distinct differentiated stages of osteoblast development. Increase of ALP activity was paralleled by an increase in cAMP accumulation in response to the above-mentioned agents. The most striking difference was observed with bradykinin-induced production of PGE2. Early stage cells (low ALP) produced high levels of PGE2, whereas cells with high ALP activity showed no bradykinin stimulation at all. This was consistent with the results of specific binding of 3H-bradykinin to its receptor and also correlated well with the bradykinin-induced signal transduction sequence (inositol triphosphate liberation and elevation of intracellular calcium levels). This was confirmed by Northern blot analysis of bradykinin receptor mRNA expression. These results indicate that the widely used osteoblast-like cell line MC3T3-E1 is synonymous for multiple sublines, representing different stages of osteoblast development. These sublines were most likely emerging from the early stage cell line due to the applied culture conditions. Moreover, distinct biochemical features are displayed in correlation to the differentiation stage, thus providing a useful model to study the molecular mechanism of osteoblast maturation.
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Affiliation(s)
- H J Leis
- University Childrens Hospital, Department of Biochemical Analysis and Mass Spectrometry, University of Graz, Austria
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Shaw AJ, Dacke CG. Cyclic nucleotides and the rapid inhibitions of bone 45Ca uptake in response to bovine parathyroid hormone and 16,16-dimethyl prostaglandin E2 in chicks. Calcif Tissue Int 1989; 44:209-13. [PMID: 2465812 DOI: 10.1007/bf02556566] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Intravenous injection of chicks with bovine parathyroid hormone (1-34) (3.3 micrograms/100 g body wt.) or 16,16-dimethyl PGE2 (5 micrograms/100 g body wt.) caused rapid (3 minute) net inhibition of 45Ca uptake into femur and calvarium. These agents also elevated bone adenosine 3',5'-cyclic monophosphate (cAMP) but not guanosine 3',5'-cyclic monophosphate (cGMP) levels at this time. Methylxanthine phosphodiesterase inhibitors (MXPI), caffeine, theophylline, and 3-isobutyl-1-methylxanthine (IBMX) (0.3-5 mg/100 g body wt.) similarly inhibited net 45Ca uptake into femur and to a lesser extent calvarium. Plasma 45Ca and total Ca levels were unaltered or showed a slight tendency to be increased over control values 3 minutes after injection. However, the effects of the non-MXPI, dibutyryl-cAMP (0.5-5 mg/100 g body wt.) on bone 45Ca uptake were negligible. Of the MXPI, only IBMX elevated total cAMP levels in chick bone at 3 minutes. These data implicate but do not confirm a mediatory role for cAMP in the rapid inhibitory actions of PTH and PGEs on bone net 45Ca uptake in chicks.
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Affiliation(s)
- A J Shaw
- School of Pharmacy and Biomedical Sciences, Portsmouth Polytechnic, UK
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Selz T, Caverzasio J, Bonjour JP. Regulation of Na-dependent Pi transport by parathyroid hormone in osteoblast-like cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1989; 256:E93-100. [PMID: 2536233 DOI: 10.1152/ajpendo.1989.256.1.e93] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the present work we investigated the influence of parathyroid hormone (PTH) on the transport of inorganic phosphate (Pi) in the osteoblast-like cell line UMR-106. Pi was transferred from the extra- to the intracellular compartment by means of a Na-dependent transport system with an apparent binding affinity for both Pi and Na similar to that recently observed in the osteoblast-like cell line ROS 17/2.8 (Calcif. Tissue Int. 43: 83-87, 1988). Exposure of confluent UMR-106 cells to PTH (10(-9)-10(-7) M) induced a concentration-related stimulation of the Na-dependent Pi transport (NaPiT). An increase in NaPiT was observed after a 1-h exposure to 10(-7) M PTH, with the maximal response occurring at 4-6 h. (PTH, 35.6 +/- 0.3; vehicle, 27.4 +/- 0.2 pmol.microgram DNA-1.4 min-1, P less than 0.001). The stimulatory effect of PTH on NaPiT was not associated with a change in the Na-dependent alanine transport. A positive correlation was observed between the increase of NaPiT and that of cAMP in response to various concentrations of PTH. Stimulation of cAMP by forskolin (10(-4) M) mimicked the effect of PTH on NaPiT. Kinetic analysis of the PTH-induced stimulation of NaPiT indicated an increase in Vmax (PTH, 226.9 +/- 6.9; vehicle, 182.9 +/- 1.9 pmol Pi/microgram DNA, P less than 0.001), with no change in Km. The increase in NaPiT by either PTH or forskolin was followed by a transient inhibition from 6 to 24 h that was associated with a decrease in the Na-dependent alanine transport.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T Selz
- Department of Medicine, University Hospital, Geneva, Switzerland
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Abstract
The methods for establishing osteoblast-rich rat calvarial cell cultures have been described, together with methods for the use of clonal osteogenic sarcoma cells of osteoblast phenotype. The latter clonal lines are useful for several purposes, but all the precautions and quality control measures necessary in the study of clonal lines must be observed. Some of the techniques for studying biochemical responses to hormones in these cells have also been detailed, but clearly others are applicable, including studies of the synthesis of matrix constituents. Osteoclast-like cells have not been considered in this chapter, because osteoclast culture methods have not yet been developed to the degree of purity and reproducibility necessary for this type of biochemical approach.
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Fletcher AE, Allan EH, Casley DJ, Martin TJ. Atrial natriuretic factor receptors and stimulation of cyclic GMP formation in normal and malignant osteoblasts. FEBS Lett 1986; 208:263-8. [PMID: 2877903 DOI: 10.1016/0014-5793(86)81029-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Synthetic rat atrial natriuretic factor (Ile-ANF-26) stimulated cyclic GMP formation by up to several hundred-fold in osteoblast-rich cultures from newborn rat calvaria and in clonal osteogenic sarcoma cells (UMR 106-01) which are phenotypically osteoblast. ANF had no effect on the cyclic AMP response to parathyroid hormone in the same cells. Specific, high-affinity binding sites for ANF were identified in both cell types, with Kd and receptor numbers in normal osteoblasts of 1.2 +/- 0.1 X 10(-10) M and 42 +/- 4 X 10(3) per cell, and in UMR 106-01 cells of 1.4 +/- 0.1 X 10(-10) M and 22 +/- 4 X 10(3) per cell.
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Sömjen D, Kaye AM, Rodan GA, Binderman I. Regulation of creatine kinase activity in rat osteogenic sarcoma cell clones by parathyroid hormone, prostaglandin E2, and vitamin D metabolites. Calcif Tissue Int 1985; 37:635-8. [PMID: 3937588 DOI: 10.1007/bf02554922] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have previously shown that both parathyroid hormone (PTH) and prostaglandin E2 (PGE2) stimulate the activity of creatine kinase BB (CKBB) in rat bone cells in culture. Therefore, morphologically distinct rat osteogenic sarcoma cells in culture were tested for stimulation of CKBB activity by hormones that regulate skeletal tissues. PTH stimulated CKBB in the osteoblast-like clone ROS 17/2; 1 alpha,25(OH)2D3 inhibited this activity while PGE2, CT and 24R,25(OH)2D3 had no significant effect. PGE2 stimulated CKBB activity in the fibroblast-like clone ROS 24/1, which was unresponsive to PTH, CT and Vitamin D metabolites. 24R,25(OH)2D3 as well as PGE2 (but not PTH, CT or 1 alpha 25(OH)2D3) stimulated CKBB in clone ROS 25/1, suggesting that this fibroblast-like clone has some chondroblast-like character. Both PTH and PGE2 stimulated the brain type isoenzyme of CK (CKBB), although the osteogenic sarcoma cell clones contain a significant proportion of the muscle type of CK (CKMM). Thus, increased CKBB activity can serve as an additional characteristic marker for the action of steroid and polypeptide hormones and for prostaglandins.
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Knazek RA, Yee CL, Costa J. Prostaglandin and hydroxyeicosatetraenoic acid synthesis by human mesenchymal tumors. Int J Cancer 1985; 36:143-52. [PMID: 2991146 DOI: 10.1002/ijc.2910360204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The metabolism of arachidonic acid was investigated by radioimmunoassay and chromatographic techniques in 5 sarcomas and one embryonal carcinoma of human origin maintained as transplantable tumors in nude mice. The results obtained indicate that: the absolute quantities of arachidonic acid metabolites produced by a given tumor varied between experiments but the overall distribution pattern of these products, in general, remained constant from passage to passage; each tumor showed a different arachidonic acid metabolite profile in quality and quantity; 2 sarcomas of the same histological type could be clearly distinguished by their arachidonic acid metabolites; the predominant product in all tumors was 12-HETE or 15-HETE, whereas thromboxane A2 was synthesized in low quantities by all tumors; PGF2 alpha was synthesized at the highest rate by an alveolar rhabdomyosarcoma; PGE2 synthesis was highest in a malignant fibrous histiocytoma; and total prostaglandin synthesis was low in the chondrosarcoma and synovial-cell sarcomas. All results reported in this study are for the complete tumor which includes both neoplastic and stromal cells. The role that these products play in the biological behavior of mesenchymal tumor cells and normal tissues of the host remains to be determined.
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Kumegawa M, Ikeda E, Tanaka S, Haneji T, Yora T, Sakagishi Y, Minami N, Hiramatsu M. The effects of prostaglandin E2, parathyroid hormone, 1,25 dihydroxycholecalciferol, and cyclic nucleotide analogs on alkaline phosphatase activity in osteoblastic cells. Calcif Tissue Int 1984; 36:72-6. [PMID: 6322941 DOI: 10.1007/bf02405296] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Clone MC3T3-E1 cells isolated from newborn mouse calvaria had the same type of alkaline phosphatase (ALP) as that found in adult mouse calvaria (the liver-bone-kidney type), as judged by polyacrylamide gel electrophoresis as well as by heat lability and amino acid inactivation. The effects of prostaglandin E2 (PGE2), parathyroid hormone (PTH), 1,25 dihydroxycholecalciferol [1,25(OH)2D3], and adenosine-3',5'-cyclic monophosphate (cAMP) analogs on ALP were investigated. PGE2 and 1,25(OH)2D3 increased ALP activity in dose-related manner with a maximal effect at concentrations of 10 ng/ml and 40 pg/ml, respectively. N6,O2-dibutyryl adenosine-3',5'-cyclic monophosphate (DBcAMP) also induced an increase in ALP activity in a dose-related fashion with a maximal effect at a concentration of 0.5 mM which was 2.2-fold over that of the controls. Induced ALP was of the "liver-bone-kidney" type. Antinomycin D and cycloheximide inhibited the increase in ALP activity induced by DBcAMP. The level of ALP was elevated by 8-bromo-adenosine-3',5'-cyclic monophosphate and theophylline, but not by N6,O2-dibutyryl guanosine-3',5'-cyclic monophosphate and sodium butyrate. Moreover, PGE2 dramatically increased the level of cAMP in the cells with a maximal effect at a concentration of 10 ng/ml, indicating that PGE2 and DBcAMP induce an increase of ALP activity in clone MC3T3-E1 cells by increasing the cAMP level; PTH did not affect enzyme activity and cAMP level in the cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
The number of agents and treatment regimens which can be used in the medical treatment of hypercalcemia has increased markedly over the last 5 yr. As this list has increased, clinicians are anxious to know more about the humoral and cellular mechanisms which are responsible for the hypercalcemia of malignancy and to understand how these drugs work. Unfortunately there is no treatment available presently which is uniformally safe and effective, and the potential pathogenetic mechanisms responsible for hypercalcemia are hotly debated. In this review, we plan to summarize current views of the pathogenesis, clinical features and treatment of hypercalcemia associated with malignant disease.
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Segal J, Ingbar SH. Studies of the mechanism by which 3,5,3'- triiodothyronine stimulates 2-deoxyglucose uptake in rat thymocytes in vitro. Role of calcium and adenosine 3':5'-monophosphate. J Clin Invest 1981; 68:103-10. [PMID: 6265495 PMCID: PMC370777 DOI: 10.1172/jci110224] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The present experiments were designed to explore the mechanism whereby 3,5,3'-triiodothyronine (T3) stimulates the uptake of 2-deoxy-D-glucose (2-DG) in rat thymocytes in vitro. Addition of T3 evoked a transient, dose-related increase in cellular cyclic (c) AMP concentrations, evident within 5 min. followed soon by an increase in 2-DG uptake. The effects of T3 on both cAMP concentration and 2-DG uptake were dependent upon the presence of extracellular calcium. Epinephrine also induced a sequential increase in thymocyte cAMP concentration and 2-DG uptake. These responses were more prompt than those to T3, but were calcium independent. As with their combined effects on 2-DG uptake, T3 and epinephrine produced synergistic or additive effects on cellular cAMP concentration. Dibutyryl cAMP also stimulated 2-DG uptake, an effect that was more prompt than that of epinephrine, and like that of epinephrine, was calcium independent. Prior or simultaneous addition of L-alprenolol (10 microM), which, we have previously shown, blocks the effect of both T3 and epinephrine on 2-DG uptake, also blocked the increase in thymocyte cAMP concentration induced by these agents. In contrast, L-alprenolol failed to block the increase in 2-DG uptake produced by dibutyryl cAMP. On the basis of these observations we suggest that T3 increases 2-DC uptake in the rat thymocyte by increasing the cellular concentration of cAMP, which then acts to enhance sugar transport. The increase in 2-DC uptake induced by epinephrine is also mediated by an increase in cAMP concentration. The greater response of cellular cAMP concentration to T3 and epinephrine when added together than to either agent added alone may explain their synergistic action to increase 2-DG uptake. We suggest that these actions of T3 and epinephrine are both initiated at the level of the plasma membrane.
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Ballard FJ, Wong SS, Knowles SE, Partridge NC, Martin TJ, Wood CM, Gunn JM. Insulin inhibition of protein degradation in cell monolayers. J Cell Physiol 1980; 105:335-46. [PMID: 7007398 DOI: 10.1002/jcp.1041050216] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Protein degradation has been measured in confluent monolayers of eleven lines of contact-inhibited cells and ten transformed lines as the rate of release of trichloroacetic acid-soluble radioactivity after prelabeling cell protein with [3H]leucine. Insulin, at contrations from 10(-12) M to 10(-6) M, has been added at the beginning of the 4-hour degradation period to detect selective effects of this hormone as an inhibitor of the inducible proteolysis occurring in serum-free medium. In addition insulin binding measurements have been performed on selected cell lines in an attempt to relate receptor properties to insulin action. Substantial effects of insulin are found in most cells with a selective inhibition at low insulin concentrations noted in several of the transformed lines. The difference in insulin sensitivity is not entirely definitive because temperature-sensitive transformation mutants of NRK cells are not more sensitive to insulin at a temperature where they show the transformed phenotype. Although insulin receptors on different cell lines have similar binding properties, two of the hepatomas used, H35 and MH1C1, show inhibition of protein degradation at insulin concentrations where receptor occupancy is extremely low. Calvarial osteoblast-like cells have a high rate of protein degradation which can be reduced by growth factors but not by insulin. The lack of an insulin response is a consequence of poor insulin binding to the cells. Insulin binds to the osteogenic sarcoma cells in substantial amounts. However, its normal action to inhibit the induced proteolysis is restricted because with these cells no increase of proteolysis occurs in serum-free medium. Generally higher rates of protein degradation are observed in the contact-inhibited lines than the transformed cells. We suggest that this difference may provide a selective growth advantage to transformed cells.
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Manolagas S, Haussler M, Deftos L. 1,25-Dihydroxyvitamin D3 receptor-like macromolecule in rat osteogenic sarcoma cell lines. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85505-9] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Atkins D, Waller PC, Martin TJ. Rat osteogenic sarcoma cells: modulation of hormone stimulated cyclic AMP production by prostaglandin antagonists and biosynthesis inhibitors. Clin Exp Pharmacol Physiol 1980; 7:31-40. [PMID: 6103768 DOI: 10.1111/j.1440-1681.1979.tb00728.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. The effects of several anti-prostaglandin drugs on parathyroid hormone (PTH) and prostaglandin E2 (PGE2) stimulated cyclic AMP production in freshly isolated rat osteogenic sarcoma cells have been studied. 2. PG biosynthesis inhibitors (aspirin and indomethacin) did not inhibit the effect of PTH and arachidonic acid did not enhance PTH responsiveness. 3. The PG antagonists (SC-19220, phloretin phosphate polymers, 7-oxa-13-prostynoic acid) all inhibited PGE2-stimulated c-AMP production whilst only the phloretin phosphate polymers at high concentrations inhibited the PTH effect. 4. The data suggest that the primary action of PTH and PGE2 on these bone-derived cells is independent and that a PG is not involved in the initial event in PTH action.
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Underwood JC, Melick RA, Loomes RS, Dangerfield VM, Crawford A, Coulton L, Ingleton PM, Martin TJ. Structural and functional correlations in parathyroid hormone responsive transplantable osteogenic sarcomas. Eur J Cancer 1979; 15:1151-8. [PMID: 294355 DOI: 10.1016/0014-2964(79)90131-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Ingleton PM, Coulton LA, Preston CJ, Martin TJ. Alkaline phosphatase in serum and tumour of rats bearing a hormone-responsive transplantable osteogenic sarcoma. Eur J Cancer 1979; 15:685-91. [PMID: 292595 DOI: 10.1016/0014-2964(79)90142-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Atkins D, Greaves M, Ibbotson KJ, Martin TJ. Role of prostaglandins in bone metabolism: a review. J R Soc Med 1979; 72:27-34. [PMID: 233243 PMCID: PMC1436756 DOI: 10.1177/014107687907200110] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Crawford A, Atkins D, Martin TJ. Rat osteogenic sarcoma cells: comparison of the effects of prostaglandins E1, E2, I2 (prostacyclin), 6-keto F1alpha and thromboxane B2 on cyclic AMP production and adenylate cyclase activity. Biochem Biophys Res Commun 1978; 82:1195-201. [PMID: 212039 DOI: 10.1016/0006-291x(78)90313-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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O'Hare MJ, Ellison ML, Neville AM. Tissue culture in endocrine research: perspectives, pitfalls, and potentials. CURRENT TOPICS IN EXPERIMENTAL ENDOCRINOLOGY 1978; 3:1-56. [PMID: 207488 DOI: 10.1016/b978-0-12-153203-1.50007-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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