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Cook GJR, Thorpe MP. Bone Metastases. Cancer J 2024; 30:202-209. [PMID: 38753755 DOI: 10.1097/ppo.0000000000000717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
ABSTRACT Bone metastases occur frequently in common malignancies such as breast and prostate cancer. They are responsible for considerable morbidity and skeletal-related events. Fortunately, there are now several systemic, focal, and targeted therapies that can improve quality and length of life, including radionuclide therapies. It is therefore important that bone metastases can be detected as early as possible and that treatment can be accurately and sensitively monitored. Several bone-specific and tumor-specific single-photon emission computed tomography and positron emission tomography molecular imaging agents are available, for detection and monitoring response to systemic therapeutics, as well as theranostic agents to confirm target expression and predict response to radionuclide therapies.
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Affiliation(s)
- Gary J R Cook
- From the Department of Cancer Imaging, School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, UK
| | - Matthew P Thorpe
- Division of Nuclear Radiology, Department of Radiology, Mayo Clinic, Rochester, MN
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2
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Cook GJR. Imaging of Bone Metastases in Breast Cancer. Semin Nucl Med 2022; 52:531-541. [PMID: 35236615 PMCID: PMC7616189 DOI: 10.1053/j.semnuclmed.2022.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/11/2022]
Abstract
Bone metastases are a common site of spread in advanced breast cancer and responsible for morbidity and high health care costs. Imaging contributes to staging and response assessment of the skeleton and has been instrumental in guiding patient management for several decades. Historically this has been with radiographs, computed tomography and bone scans. More recently, molecular and hybrid imaging methods have undergone significant development, including the addition of single photon emission computed tomography/computed tomography to the bone scan, positron emission tomography, with bone-specific and tumor-specific tracers, and magnetic resonance imaging with complementary functional diffusion-weighted imaging. These have allowed different aspects of the abnormal biology associated with bone metastases to be explored. There is ability to interrogate the bone microenvironment with bone-specific tracers and cancer cell characteristics with tumor-specific methods that complement morphological appearances on computed tomography or magnetic resonance imaging. Alongside the advent of novel, more effective and nuanced therapies for bone metastases in breast cancer, there is accumulating evidence that the developments in imaging allow more sensitive and specific detection of bone metastases as well as more accurate and earlier assessment of treatment response leading to improvements in patient management.
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Affiliation(s)
- Gary J R Cook
- Cancer Imaging Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK; King's College London & Guy's and St Thomas' PET Centre, St Thomas' Hospital, London, UK.
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3
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Zhao W, Wiedemann P, Wölfel EM, Neven M, Peters S, Imhof T, Koch M, Busse B, Amling M, Schinke T, Yorgan TA. Decreased Trabecular Bone Mass in Col22a1-Deficient Mice. Cells 2021; 10:3020. [PMID: 34831244 PMCID: PMC8616175 DOI: 10.3390/cells10113020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022] Open
Abstract
The bone matrix is constantly remodeled by the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts. Whereas type I collagen is the most abundant bone matrix protein, there are several other proteins present, some of them specifically produced by osteoblasts. In a genome-wide expression screening for osteoblast differentiation markers we have previously identified two collagen-encoding genes with unknown function in bone remodeling. Here we show that one of them, Col22a1, is predominantly expressed in bone, cultured osteoblasts, but not in osteoclasts. Based on this specific expression pattern we generated a Col22a1-deficient mouse model, which was analyzed for skeletal defects by µCT, undecalcified histology and bone-specific histomorphometry. We observed that Col22a1-deficient mice display trabecular osteopenia, accompanied by significantly increased osteoclast numbers per bone surface. In contrast, cortical bone parameters, osteoblastogenesis or bone formation were unaffected by the absence of Col22a1. Likewise, primary osteoblasts from Col22a1-deficient mice did not display a cell-autonomous defect, and they did not show altered expression of Rankl or Opg, two key regulators of osteoclastogenesis. Taken together, we provide the first evidence for a physiological function of Col22a1 in bone remodeling, although the molecular mechanisms explaining the indirect influence of Col22a1 deficiency on osteoclasts remain to be identified.
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Affiliation(s)
- Wenbo Zhao
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Philip Wiedemann
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Eva Maria Wölfel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Mona Neven
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Stephanie Peters
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Thomas Imhof
- Center for Biochemistry, Medical Faculty, University of Cologne, 50923 Cologne, Germany; (T.I.); (M.K.)
- Medical Faculty, Institute for Dental Research and Oral Musculoskeletal Biology, University of Cologne, 50923 Cologne, Germany
| | - Manuel Koch
- Center for Biochemistry, Medical Faculty, University of Cologne, 50923 Cologne, Germany; (T.I.); (M.K.)
- Medical Faculty, Institute for Dental Research and Oral Musculoskeletal Biology, University of Cologne, 50923 Cologne, Germany
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
| | - Timur Alexander Yorgan
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (W.Z.); (P.W.); (E.M.W.); (M.N.); (S.P.); (B.B.); (M.A.)
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Abstract
Radiolabeled bisphosphonates were developed in the 1970s for scintigraphic functional imaging of the skeleton in benign and malignant disease. Tracers such as 99mTc-methylene diphosphonate, that map focal or global changes in mineralization in the skeleton qualitatively and quantitatively, have been the backbone of nuclear medicine imaging for decades. While competing technologies are evolving, new indications and improvements in scanner hardware, in particular hybrid imaging (e.g. single photon emission computed tomography combined with computed tomography), have allowed improved diagnostic accuracy and a continued role for radiolabeled bisphosphonate imaging in current practice.
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Affiliation(s)
- Gary J R Cook
- Department of Cancer Imaging, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
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Engineering of L-Plastin Peptide-Loaded Biodegradable Nanoparticles for Sustained Delivery and Suppression of Osteoclast Function In Vitro. Int J Cell Biol 2019; 2019:6943986. [PMID: 31191656 PMCID: PMC6525930 DOI: 10.1155/2019/6943986] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/09/2019] [Accepted: 04/15/2019] [Indexed: 12/15/2022] Open
Abstract
We have recently demonstrated that a small molecular weight amino-terminal peptide of L-plastin (10 amino acids; “MARGSVSDEE”) suppressed the phosphorylation of endogenous L-plastin. Therefore, the formation of nascent sealing zones (NSZs) and bone resorption are reduced. The aim of this study was to develop a biodegradable and biocompatible PLGA nanocarrier that could be loaded with the L-plastin peptide of interest and determine the efficacy in vitro in osteoclast cultures. L-plastin MARGSVSDEE (P1) and scrambled control (P3) peptide-loaded PLGA-PEG nanoparticles (NP1 and NP3, respectively) were synthesized by double emulsion technique. The biological effect of nanoparticles on osteoclasts was evaluated by immunoprecipitation, immunoblotting, rhodamine-phalloidin staining of actin filaments, and pit forming assays. Physical characterization of well-dispersed NP1 and NP3 demonstrated ~130-150 nm size, < 0.07 polydispersity index, ~-3 mV ζ-potential, and a sustained release of the peptide for three weeks. Biological characterization in osteoclast cultures demonstrated the following: NP1 significantly reduced (a) endogenous L-plastin phosphorylation; (b) formation of NSZs and sealing rings; (c) resorption. However, the assembly of podosomes which are critical for cell adhesion was not affected. L-plastin peptide-loaded PLGA-PEG nanocarriers have promising potential for the treatment of diseases associated with bone loss. Future studies will use this sustained release of peptide strategy to systematically suppress osteoclast bone resorption activity in vivo in mouse models demonstrating bone loss.
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Bone morphogenetic proteins: Their role in regulating osteoclast differentiation. Bone Rep 2019; 10:100207. [PMID: 31193008 PMCID: PMC6513777 DOI: 10.1016/j.bonr.2019.100207] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 02/07/2023] Open
Abstract
The ability to create recombinant bone morphogenetic proteins (BMPs) in recent years has led to their rise as a common clinical adjuvant. Their application varies, from spinal fixation to repairing palatal clefts, to coating implants for osseointegration. In recent years questions have been raised as to the efficacy of BMPs in several of these procedures. These questions are due to the unwanted side effect of BMPs on other cell types, such as osteoclasts which can resorb bone at the graft/implant site. However, most BMP research focuses on the anabolic osteoinductive effects of BMPs on osteoblasts rather than its counterpart- stimulation of the osteoclasts, which are cells responsible for resorbing bone. In this review, we discuss the data available from multiple in-vitro and in-vivo BMP-related knockout models to elucidate the different functions BMPs have on osteoclast differentiation and activity. BMPs can act directly on osteoclasts to regulate differentiation and activity. Osteoclasts express multiple BMP signaling components. BMPs signal through both SMAD independent and dependent mechanisms in osteoclasts. SMAD dependent BMP signaling regulates osteoclast-osteoblast coupling factors.
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Cook GJ, Goh V. Functional and Hybrid Imaging of Bone Metastases. J Bone Miner Res 2018; 33:961-972. [PMID: 29665140 PMCID: PMC7616187 DOI: 10.1002/jbmr.3444] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 04/02/2018] [Accepted: 04/06/2018] [Indexed: 12/21/2022]
Abstract
Bone metastases are common, cause significant morbidity, and impact on healthcare resources. Although radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy have frequently been used for staging the skeleton, these methods are insensitive and nonspecific for monitoring treatment response in a clinically relevant time frame. We summarize several recent reports on new functional and hybrid imaging methods including single photon emission CT/CT, positron emission tomography/CT, and whole-body MRI with diffusion-weighted imaging. These modalities generally show improvements in diagnostic accuracy for staging and response assessment over standard imaging methods, with the ability to quantify biological processes related to the bone microenvironment as well as tumor cells. As some of these methods are now being adopted into routine clinical practice and clinical trials, further evaluation with comparative studies is required to guide optimal and cost-effective clinical management of patients with skeletal metastases. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Gary Jr Cook
- Department of Cancer Imaging, School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London SE1 7EH, United Kingdom
- King's College London and Guy's & St Thomas' PET Centre, St Thomas' Hospital, London SE1 7EH, United Kingdom
| | - Vicky Goh
- Department of Cancer Imaging, School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London SE1 7EH, United Kingdom
- Radiology Department, Guy's & St Thomas' Hospitals, London SE1 7EH, United Kingdom
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8
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Cook GJR, Azad GK, Taylor BP, Lee E, Morrison MS, Hughes S, Morris S, Rudman S, Chowdhury S, Goh V. Imaging α vβ 3 integrin expression in skeletal metastases with 99mTc-maraciclatide single-photon emission computed tomography: detection and therapy response assessment. Eur J Nucl Med Mol Imaging 2018; 45:898-903. [PMID: 29396636 PMCID: PMC5915496 DOI: 10.1007/s00259-017-3926-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/27/2017] [Indexed: 11/18/2022]
Abstract
PURPOSE Osteoclast activity is an important factor in the pathogenesis of skeletal metastases and is a potential therapeutic target. This study aimed to determine if selective uptake of 99mTc-maraciclatide, a radiopharmaceutical targeting αvβ3 integrin, occurs in prostate cancer (PCa) bone metastases and to observe the changes following systemic therapy. METHODS The study group comprised 17 men with bone-predominant metastatic PCa who underwent whole-body planar and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging with 99mTc-maraciclatide before (n = 17) and 12 weeks after (n = 11) starting treatment with abiraterone. Tumour to normal bone (T:N) ratios, tumour to muscle (T:M) ratios and CT Hounsfield units (HU) were measured in up to five target metastases in each subject. An oncologist blinded to study scans assessed clinical responses up to 24 weeks using conventional criteria. RESULTS Before treatment, metastases showed specific 99mTc-maraciclatide accumulation (mean planar T:N and T:M ratios 1.43 and 3.06; SPECT T:N and T:M ratios 3.1 and 5.19, respectively). Baseline sclerotic lesions (389-740 HU) showed lower T:M ratios (4.22 vs. 7.04, p = 0.02) than less sclerotic/lytic lesions (46-381 HU). Patients with progressive disease (PD; n = 5) showed increased planar T:N and T:M ratios (0.29 and 12.1%, respectively) and SPECT T:N and T:M ratios (11.9 and 20.2%, respectively). Patients without progression showed decreased planar T:N and T:M ratios (0.27 and -8.0%, p = 1.0 and 0.044, respectively) and SPECT T:N and T:M ratios (-21.9, and -27.2%, p = 0.3 and 0.036, respectively). The percentage change in CT HU was inversely correlated with the percentage change in SPECT T:M ratios (r = -0.59, p = 0.006). CONCLUSIONS 99mTc-maraciclatide accumulates in PCa bone metastases in keeping with increased αvβ3 integrin expression. Greater activity in metastases with lower CT density suggests that uptake is related to osteoclast activity. Changes in planar and SPECT T:M ratios after 12 weeks of treatment differed between patients with and without PD and 99mTc-maraciclatide imaging may be a potential method for assessing early response.
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Affiliation(s)
- Gary J R Cook
- Cancer Imaging Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
- Nuclear Medicine Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK.
| | - Gurdip K Azad
- Cancer Imaging Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Benjamin P Taylor
- Uro-oncology Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | - Eugene Lee
- Nuclear Medicine Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | | | - Simon Hughes
- Uro-oncology Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | - Stephen Morris
- Uro-oncology Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | - Sarah Rudman
- Uro-oncology Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | - Simon Chowdhury
- Uro-oncology Department, Guy's and St Thomas' Hospitals NHS Trust, London, UK
| | - Vicky Goh
- Cancer Imaging Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
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9
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A novel miR17/protein tyrosine phosphatase-oc/EphA4 regulatory axis of osteoclast activity. Arch Biochem Biophys 2018; 650:30-38. [PMID: 29763590 PMCID: PMC5985224 DOI: 10.1016/j.abb.2018.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 05/08/2018] [Accepted: 05/11/2018] [Indexed: 12/17/2022]
Abstract
Information about the molecular mechanisms leading to the activation of the osteoclast is relatively limited. While there is compelling evidence that the signaling mechanisms of Src and integrin β3 are essential for osteoclast activation, the regulation of these two signaling mechanisms is not fully understood. In this review, evidence supporting a novel regulatory axis of osteoclast activation that plays an upstream regulatory role in both the Src and integrin β3 signaling during osteoclast activation is discussed. This regulatory axis contains three unique components: a structurally unique transmembrane protein-tyrosine phosphatase, PTP-oc, EphA4, and miR17. In the first component, PTP-oc activates the Src signaling through dephosphorylation of the inhibitory tyr-527 of Src. This in turn activates the integrin β3 signaling, enhances the JNK2/NFκB signaling, promotes the ITAM/Syk signaling, and suppresses the ITIM/Shp1 signaling; the consequence of which is activation of the osteoclast. In the second component, EphA4 inhibits osteoclast activity by suppressing the integrin β3 signaling. PTP-oc relieves the suppressive actions of EphA4 by directly dephosphorylating EphA4. In the third component, PTP-oc expression is negatively regulated by miR17. Accordingly, suppression of miR17 during osteoclast activation upregulates the PTP-oc signaling and suppresses the EphA4 signaling, resulting in the activation of the osteoclast. This regulatory axis is unique, in that each of the three components acts to exert suppressive action on their respective immediate downstream inhibitory step. Because the final downstream event is the EphA4-mediated inhibition of osteoclast activation, the overall effect of this mechanism is the stimulation of osteoclast activity.
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Lau KHW, Stiffel VM, Rundle CH, Amoui M, Tapia J, White TD, Sheng MHC. Conditional Disruption of miR17~92 in Osteoclasts Led to Activation of Osteoclasts and Loss of Trabecular Bone In Part Through Suppression of the miR17-Mediated Downregulation of Protein-Tyrosine Phosphatase-oc in Mice. JBMR Plus 2017; 1:73-85. [PMID: 29082358 PMCID: PMC5656011 DOI: 10.1002/jbm4.10014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
This study sought to understand the regulation of an osteoclastic protein-tyrosine phosphatase (PTP-oc), a positive regulator of osteoclast activaty. Our past studies suggested that PTP-oc is regulated post-transcriptionally. The 3'-UTR of PTP-oc mRNA contains a target site for miR17. During osteoclastic differentiation, there was an inverse relationship between the cellular levels of miR17 (expressed as one of the six cluster genes of miR17~92) and PTP-oc mRNA. Overexpression of pre-miR17~92 in mouse osteoclast precursors reduced PTP-oc mRNA level and the size of the derived osteoclasts; whereas deletion of miR17~92 or inhibition of miR17 resulted in the formation of larger osteoclasts containing more nuclei that expressed higher PTP-oc mRNA levels and created larger resorption pits. Thus, PTP-oc-mediated osteoclast activation is modulated in part by miR17~92, particularly miR17. The miR17~92 osteoclast conditional knockout (cKO) mutants, generated by breeding miR17~92loxp/loxp mice with Ctsk-Cre mice, had lower Tb.BV/TV, Tb.BMD, Tb.Conn-Dens, Tb.N, and Tb.Th, but larger Tb.Sp, and greater bone resorption without a change in bone formation compared to littermate controls. The cKO marrow-derived osteoclasts were twice as large, contained twice as many nuclei, and produced twice as large resorption pits as osteoclasts of littermate controls. The expression of genes associated with osteoclast activation was increased in cKO osteoclasts, suggesting that deletion of miR17~92 in osteoclasts promotes osteoclast activation. The cKO osteoblasts did not show differences in cellular miR17 level, alkaline phosphatase activity, and bone nodule formation ability. In conclusion, miR17-92 negatively regulates the osteoclast activity, in part via the miR17-mediated suppression of PTP-oc in osteoclasts.
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Affiliation(s)
- Kin-Hing William Lau
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A.,Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California 92350, U.S.A
| | - Virginia M Stiffel
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A
| | - Charles H Rundle
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A.,Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California 92350, U.S.A
| | - Mehran Amoui
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A
| | - Jordan Tapia
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A
| | - Tyler D White
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial V.A. Medical Center, Loma Linda, California 92357, U.S.A
| | - Matilda H-C Sheng
- Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California 92350, U.S.A
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11
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Chen X, Zhang K, Hock J, Wang C, Yu X. Enhanced but hypofunctional osteoclastogenesis in an autosomal dominant osteopetrosis type II case carrying a c.1856C>T mutation in CLCN7. Bone Res 2016; 4:16035. [PMID: 27990310 PMCID: PMC5126728 DOI: 10.1038/boneres.2016.35] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/03/2016] [Accepted: 08/25/2016] [Indexed: 02/05/2023] Open
Abstract
Type II autosomal dominant osteopetrosis (ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7 (CLCN7) gene. The osteopetrosis of ADO2 has been attributed to hypofunctional osteoclasts. The mechanism underlying the abnormality in osteoclast function remains largely unknown. This study was designed to investigate gene mutations and osteoclast function in a case that was clinically diagnosed as ADO2. Genomic DNA was extracted from blood samples of this patient, and the 25 exons of CLCN7 were amplified. Peripheral blood from the ADO2 subject and a healthy age- and sex-matched control was used to evaluate osteoclastogenesis, osteoclast morphology, and bone resorption. Analysis of DNA from the patient showed a germline heterozygous missense mutation, c.1856C>T (p.P619L), in exon 20 of CLCN7. A similar homozygous mutation at this site was previously reported in a patient with autosomal recessive osteopetrosis. When cultured, the peripheral blood mononuclear cells (PBMCs) from the ADO2 patient spontaneously differentiated into mature osteoclasts in vitro. The ADO2 patient’s PBMCs formed enhanced, but heterogeneous, osteoclasts in both the presence and absence of macrophage-colony stimulating factor, and nuclear factor-ĸB ligand. Bone resorption was reduced in the ADO2 patient’s osteoclasts, which exhibited aberrant morphology and abnormal distribution of integrin avβ3. Gene analysis found increased c-fos expression and reduced RhoA and integrin beta 3 expression in ADO2 cells. In conclusion, our data suggest that enhanced, heterogeneous osteoclast induction may be an intrinsic characteristic of ADO2.
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Affiliation(s)
- Xiang Chen
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu, China
| | - Kun Zhang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu, China
| | - Janet Hock
- The Polis Center, Indiana University-Purdue University Indianapolis , Indianapolis, IN, USA
| | - Chunyu Wang
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu, China
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12
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Jiang H, Sui Y, Cui Y, Lin P, Li W, Xing S, Wang D, Hu M, Fu X. Expression, purification, and characterization of human osteoclastic protein-tyrosine phosphatase catalytic domain in Escherichia coli. Protein Expr Purif 2015; 107:7-12. [DOI: 10.1016/j.pep.2014.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/10/2014] [Accepted: 11/16/2014] [Indexed: 10/24/2022]
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13
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Gruber R. Molecular and cellular basis of bone resorption. Wien Med Wochenschr 2014; 165:48-53. [PMID: 25223736 DOI: 10.1007/s10354-014-0310-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 10/24/2022]
Abstract
Osteoclast research has an exciting history and a challenging future. More than 3 decades ago, it became evident that bone-resorbing osteoclasts are of hematopoietic origin and are ultimately linked to the "basic multicellular unit," where they team up with the other cell types, including bone-forming osteoblasts. Since 2 decades, we have learned about the signaling pathways controlling genes relevant for osteoclastogenesis and bone resorption. It took another decade until the hypothesized "osteoclast differentiation" factor was discovered and was translated into an approved pharmacologic strategy. Here, the focus is on another molecular target, cathepsin K, a cysteine protease being released by the osteoclast into the resorption compartment. Genetic deletion and pharmacological blocking of cathepsin K reduces bone resorption but with ongoing bone formation. This observation not only holds great promise to become a new pharmacologic strategy, but it also provides new insights into the coordinated work of cells in the "basic multicellular unit" and thus, bridges the history and future of osteoclast research. This article is a short primer on osteoclast biology for readers of the special issue on odanacatib, a cathepsin K inhibitor.
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Affiliation(s)
- Reinhard Gruber
- Laboratory of Oral Cell Biology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010, Bern, Switzerland,
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14
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Boyce BF, Rosenberg E, de Papp AE, Duong LT. The osteoclast, bone remodelling and treatment of metabolic bone disease. Eur J Clin Invest 2012; 42:1332-41. [PMID: 22998735 DOI: 10.1111/j.1365-2362.2012.02717.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Bone remodelling maintains skeletal integrity by osteoclasts removing foci of damaged bone and osteoblasts replacing them with new bone. Diseases associated with increased bone resorption have increased remodelling often with inadequate bone formation and increased risk of fracture. New therapies are needed for these diseases to reduce resorption and increase formation. DESIGN The molecular mechanisms regulating osteoclast and osteoblast functions have become better understood in the past 20 years and have led to questioning of the long-held notion that osteoblastic cells have the dominant regulatory role over osteoclastic cells in bone remodelling. Here, we review current knowledge of how osteoclast formation and functions are regulated and describe how enhanced understanding of these has led to development of new drugs for the management of common bone diseases characterized by increased bone resorption. RESULTS Osteoclast formation and functions are regulated by cytokines, especially receptor activator of NF-κB ligand (RANKL) and macrophage-colony-stimulating factor (M-CSF). The differentiation, activity and lifecycle of osteoclasts are regulated in part by other cells that reside within the bone. These include osteoblasts, osteocytes and immune cells, which express these cytokines in response to most factors that promote bone resorption. RANKL and M-CSF activate numerous signalling pathways, which are potential targets for therapeutic intervention. Importantly, osteoclastic cells also function as positive and negative regulators of osteoblastic bone formation. CONCLUSIONS There are multiple targets within osteoclasts for pharmacologic intervention to prevent bone loss in osteoporosis and other resorptive bone diseases. However, novel therapies could also affect osteoblastic cell functions.
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Affiliation(s)
- Brendan F Boyce
- Department ofPathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Faloni APDS, Sasso-Cerri E, Rocha FRG, Katchburian E, Cerri PS. Structural and functional changes in the alveolar bone osteoclasts of estrogen-treated rats. J Anat 2011; 220:77-85. [PMID: 22092353 DOI: 10.1111/j.1469-7580.2011.01449.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study investigated structural and functional features of apoptotic alveolar bone osteoclasts in estrogen-treated rats. For this purpose, 15 female rats 22 days old were divided into three groups: Estrogen (EG), Sham (SG) and Control (CG). The rats of EG received daily intramuscular injection of estrogen for 7 days. The SG received only the oil vehicle. Maxillary fragments containing alveolar bone were removed and processed for light and transmission electron microscopy. Area (OcA) and number of nuclei (OcN) and bone resorption surface per TRAP-positive osteoclasts (BS/OC) were obtained. Vimentin, caspase-3 and MMP-9 immunoreactions, TUNEL/TRAP and MMP-9/TUNEL combined reactions were performed. In EG, the OcA, OcN and BS/Oc were reduced. Moreover, osteoclasts showed cytoplasm immunolabelled by caspase-3 and a different pattern of vimentin expression in comparison with CG and SG. MMP-9 expression was not affected by estrogen and the TUNEL-positive osteoclasts were MMP-9-immunolabelled. In EG, ultrastructural images showed that apoptotic osteoclasts did not exhibit ruffled borders or clear zones and were shedding mononucleated portions. TRAP-positive structures containing irregular and dense chromatin were partially surrounded by fibroblast-like cells. In conclusion, the reduction in the BS/Oc may be due to reduction in OcA and OcN; these effects seem to be related to vimentin disarrangement rather than to an interference of estrogen with osteoclast MMP-9 expression. Osteoclast apoptosis involves caspase-3 activity and vimentin degradation; these cells release portions containing one apoptotic nucleus and, subsequently, undergo fragmentation, giving rise to apoptotic bodies.
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Kohli SS, Kohli VS. Role of RANKL-RANK/osteoprotegerin molecular complex in bone remodeling and its immunopathologic implications. Indian J Endocrinol Metab 2011; 15:175-181. [PMID: 21897893 PMCID: PMC3156536 DOI: 10.4103/2230-8210.83401] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Bone remodeling is a cyclic and continuous physiological process, which ensures the conservation and renewal of the bone matrix. Osteosynthesis of the bone matrix is achieved by osteoblasts and coordinated within this complex machinery of bone remodeling with resorption of extracellular bone matrix performed by osteoclasts. The mismatch between the activities of osteoblasts and osteoclasts has immunopathologic implications associated with either a decrease or increase of bone mass mineral density. The balance of the trimolecular control factor complex composed of osteoprotegerin (OPG), RANKL (osteoprotegerin ligand) and RANK maintains physiologic bone remodeling. This trimolecular complex functions as receptors and ligands and belongs to the superfamily of tumor necrosis factor (TNF). This mini review highlights the complex interplay of the RANKL-RANK/OPG axis and their immunopathologic implications in clinical medicine.
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Affiliation(s)
- Sarvraj Singh Kohli
- Department of Orthodontics and Dentofacial Orthopaedics, Hitkarini Dental College and Hospital, Dumna Road, Jabalpur 482005, Madhya Pradesh, India
| | - Virinder Singh Kohli
- Department of Orthodontics and Dentofacial Orthopaedics, Hitkarini Dental College and Hospital, Dumna Road, Jabalpur 482005, Madhya Pradesh, India
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Karlström E, Ek-Rylander B, Wendel M, Andersson G. Isolation and phenotypic characterization of a multinucleated tartrate-resistant acid phosphatase–positive bone marrow macrophage. Exp Hematol 2011; 39:339-350.e3. [DOI: 10.1016/j.exphem.2010.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 12/06/2010] [Accepted: 12/21/2010] [Indexed: 01/01/2023]
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18
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ROSENTHAL MA, DAVIDSON P, ROLLAND F, CAMPONE M, XUE L, HAN TH, MEHTA A, BERD Y, HE W, LOMBARDI A. Evaluation of the safety, pharmacokinetics and treatment effects of an ανβ3integrin inhibitor on bone turnover and disease activity in men with hormone-refractory prostate cancer and bone metastases. Asia Pac J Clin Oncol 2010; 6:42-8. [DOI: 10.1111/j.1743-7563.2009.01266.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lisignoli G, Codeluppi K, Todoerti K, Manferdini C, Piacentini A, Zini N, Grassi F, Cattini L, Piva R, Rizzoli V, Facchini A, Giuliani N, Neri A. Gene array profile identifies collagen type XV as a novel human osteoblast-secreted matrix protein. J Cell Physiol 2009; 220:401-9. [PMID: 19365806 DOI: 10.1002/jcp.21779] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Bone marrow stromal cells (MSCs) and osteoblasts are the two main non-haematopoietic cellular components of human bone tissue. To identify novel osteoblast-related molecules, we performed a gene expression profiling analysis comparing MSCs and osteoblasts isolated from the same donors. Genes differentially overexpressed in osteoblasts were mainly related to the negative control of cell proliferation, pro-apoptotic processes, protein metabolism and bone remodelling. Notably, we also identified the collagen XV (COL15A1) gene as the most up-regulated gene in osteoblasts compared with MSCs, previously described as being expressed in the basement membrane in other cell types. The expression of collagen type XV was confirmed at the protein level on isolated osteoblasts and we demonstrated that it significantly increases during the osteogenic differentiation of MSCs in vitro and that free ionised extracellular calcium significantly down-modulates its expression. Moreover, light and electron microscopy showed that collagen type XV is expressed in bone tissue biopsies mainly by working osteoblasts forming new bone tissue or lining bone trabeculae. To our knowledge, these data represent the first evidence of the expression of collagen type XV in human osteoblasts, a calcium-regulated protein which correlates to a specific functional state of these cells.
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Affiliation(s)
- Gina Lisignoli
- Laboratorio di Immunologia e Genetica, Istituto Ortopedico Rizzoli, Bologna, Italy.
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Abstract
Osteoclasts, the primary cell type mediating bone resorption, are multinucleated, giant cells derived from hematopoietic cells of monocyte-macrophage lineage. Osteoclast activity is, in a large part, regulated by protein-tyrosine phosphorylation. While information about functional roles of several protein-tyrosine kinases (PTK), including c-Src, in osteoclastic resorption has been accumulated, little is known about the roles of protein-tyrosine phosphatases (PTPs) in regulation of osteoclast activity. Recent evidence implicates important regulatory roles for four PTPs (SHP-1, cyt-PTP-epsilon, PTP-PEST, and PTPoc) in osteoclasts. Cyt-PTP-epsilon, PTP-PEST, and PTP-oc are positive regulators of osteoclast activity, while SHP-1 is a negative regulator. Of these PTPs in osteoclasts, only PTP-oc is a positive regulator of c-Src PTK through dephosphorylation of the inhibitory phosphotyrosine-527 residue. Although some information about mechanisms of action of these PTPs to regulate osteoclast activity is reviewed in this article, much additional work is required to provide more comprehensive details about their functions in osteoclasts.
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Affiliation(s)
- M. H.-C. Sheng
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, 11201 Benton Street, Loma Linda, CA 92357 USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92350 USA
| | - K.-H. W. Lau
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, 11201 Benton Street, Loma Linda, CA 92357 USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92350 USA
- Department of Biochemistry, Loma Linda University, Loma Linda, CA 92350 USA
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Abstract
Osteoclasts are the cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity. They are derived from precursors in the myeloid/ monocyte lineage that circulate in the blood after their formation in the bone marrow. These osteoclast precursors (OCPs) are attracted to sites on bone surfaces destined for resorption and fuse with one another to form the multinucleated cells that resorb calcified matrixes under the influence of osteoblastic cells in bone marrow. Recent studies have identified functions for OCPs and osteoclasts in and around bone other than bone resorption. For example, they regulate the differentiation of osteoblast precursors and the movement of hematopoietic stem cells from the bone marrow to the bloodstream; they participate in immune responses, and secrete cytokines that can affect their own functions and those of other cells in inflammatory and neoplastic processes affecting bone. Here, we review these findings, which define new roles for osteoclasts and OCPs in the growing field of osteoimmunology and in common pathologic conditions in which bone resorption is increased.
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Affiliation(s)
- Brendan F Boyce
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Yao W, Cheng Z, Busse C, Pham A, Nakamura MC, Lane NE. Glucocorticoid excess in mice results in early activation of osteoclastogenesis and adipogenesis and prolonged suppression of osteogenesis: a longitudinal study of gene expression in bone tissue from glucocorticoid-treated mice. ACTA ACUST UNITED AC 2008; 58:1674-86. [PMID: 18512788 DOI: 10.1002/art.23454] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Glucocorticoid (GC) excess induces alterations in bone metabolism that weaken bone structure and increase fracture risk. The aim of this study was to identify genes associated with bone metabolism in GC-treated mice, by performing a microarray analysis. METHODS Long bones from mice exposed to GC excess were collected after 0, 7, 28, and 56 days of treatment, to measure bone microarchitecture and extract RNA for microarray analyses. RESULTS Bone loss in this animal model was confirmed by changes in bone turnover markers as well as bone architecture, as measured by microfocal computed tomography. GC excess induced an early up-regulation of genes involved in osteoclast activation, function, and adipogenesis, which peaked on day 7. The expression of genes associated with osteoclast cytoskeletal reorganization and genes associated with matrix degradation peaked on day 28. On day 28 and day 56, the expression of genes associated with osteoblast activation and maturation was decreased from baseline, while the expression of Wnt antagonists was increased. In addition, the expression of genes expressed in osteocytes associated with bone mineralization was significantly higher at the later time points, day 28 and day 56. Reverse transcription-polymerase chain reaction confirmed the results of microarray analysis in selected genes. CONCLUSION GC excess is associated with early activation of genes associated with osteoclastogenesis and adipogenesis and a later suppression of genes associated with osteogenesis and mineralization. Novel interventions with agents that modulate either Wnt signaling or mineralization may be effective in GC-induced osteoporosis.
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Affiliation(s)
- Wei Yao
- University of California at Davis Medical Center, Sacramento, CA 95817, USA
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Sheng MHC, Wergedal JE, Mohan S, Lau KHW. Osteoactivin is a novel osteoclastic protein and plays a key role in osteoclast differentiation and activity. FEBS Lett 2008; 582:1451-8. [PMID: 18381073 DOI: 10.1016/j.febslet.2008.03.030] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 03/18/2008] [Accepted: 03/20/2008] [Indexed: 01/22/2023]
Abstract
This study presents gene expression, protein expression, and in situ immunohistochemical evidence that osteoclasts express high levels of osteoactivin (OA), which had previously been reported to be an osteoblast-specific protein in bone. OA expression in osteoclasts was up-regulated upon receptor activator of NFkappaB ligand-induced differentiation. Suppression of functional activity of OA with neutralizing antibody reduced cell size, number of nuclei, fusion, and bone resorption activity of osteoclasts. OA was co-immunoprecipitated with integrin beta3 and beta1, indicating that OA co-localizes with integrin beta3 and/or beta1 in a hetero-polymeric complex in osteoclasts. These findings indicate that OA is a novel osteoclastic protein and plays a role in osteoclast differentiation and/or activity.
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Affiliation(s)
- Matilda H-C Sheng
- Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA 92357, USA.
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25
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Pearse RN. New strategies for the treatment of metastatic bone disease. Clin Breast Cancer 2008; 8 Suppl 1:S35-45. [PMID: 18282368 DOI: 10.3816/cbc.2007.s.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The introduction of bisphosphonates represents an important advance in the care of patients with metastatic bone disease. Nonetheless, we remain unable to prevent metastatic bone destruction. This review will discuss several novel therapies, including inhibitors of receptor activator of nuclear factor-kappabeta, c-Src, mammalian target of rapamycin, cathepsin K, and alpha(5)beta(3) integrins, which could improve our control over this devastating complication.
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Affiliation(s)
- Roger N Pearse
- Department of Medicine, Division of Hematology/Medical Oncology, Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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26
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Boyce BF, Xing L. Functions of RANKL/RANK/OPG in bone modeling and remodeling. Arch Biochem Biophys 2008; 473:139-46. [PMID: 18395508 DOI: 10.1016/j.abb.2008.03.018] [Citation(s) in RCA: 1170] [Impact Index Per Article: 73.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 03/18/2008] [Accepted: 03/19/2008] [Indexed: 12/11/2022]
Abstract
The discovery of the RANKL/RANK/OPG system in the mid 1990s for the regulation of bone resorption has led to major advances in our understanding of how bone modeling and remodeling are regulated. It had been known for many years before this discovery that osteoblastic stromal cells regulated osteoclast formation, but it had not been anticipated that they would do this through expression of members of the TNF superfamily: receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG), or that these cytokines and signaling through receptor activator of NF-kappaB (RANK) would have extensive functions beyond regulation of bone remodeling. RANKL/RANK signaling regulates osteoclast formation, activation and survival in normal bone modeling and remodeling and in a variety of pathologic conditions characterized by increased bone turnover. OPG protects bone from excessive resorption by binding to RANKL and preventing it from binding to RANK. Thus, the relative concentration of RANKL and OPG in bone is a major determinant of bone mass and strength. Here, we review our current understanding of the role of the RANKL/RANK/OPG system in bone modeling and remodeling.
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Affiliation(s)
- Brendan F Boyce
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 626, Rochester, NY 14642, USA.
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Yao Z, Xing L, Qin C, Schwarz EM, Boyce BF. Osteoclast precursor interaction with bone matrix induces osteoclast formation directly by an interleukin-1-mediated autocrine mechanism. J Biol Chem 2008; 283:9917-24. [PMID: 18250170 DOI: 10.1074/jbc.m706415200] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Interleukin-1 (IL-1) and tumor necrosis factor (TNF) mediate bone resorption in a variety of diseases affecting bone. Like TNF, IL-1 is secreted by osteoclast precursors (OCPs), but unlike TNF, it does not induce osteoclast formation directly from OCPs in vitro. TNF induces IL-1 expression and activates c-Fos, a transcription factor required in OCPs for osteoclast formation. Here, we examined whether IL-1 can induce osteoclast formation directly from OCPs overexpressing c-Fos and whether interaction with bone matrix affects OCP cytokine expression. We infected OCPs with c-Fos or green fluorescent protein retrovirus, cultured them with macrophage colony-stimulating factor and IL-1 on bone slices or plastic dishes, and assessed osteoclast and resorption pit formation and expression of IL-1 by OCPs. We used a Transwell assay to determine whether OCPs secrete IL-1 when they interact with bone matrix. IL-1 induced osteoclast formation directly from c-Fos-expressing OCPs on plastic. c-Fos-expressing OCPs formed osteoclasts spontaneously on bone slices without addition of cytokines. OCPs on bone secreted IL-1, which induced osteoclast formation from c-Fos-expressing OCPs in the lower Transwell dishes. The bone matrix proteins dentin sialoprotein and osteopontin, but not transforming growth factor-beta, stimulated OCP expression of IL-1 and induced c-Fos-expressing OCP differentiation into osteoclasts. Osteoclasts eroding inflamed joints have higher c-Fos expression compared with osteoclasts inside bone. We conclude that OCPs expressing c-Fos may induce their differentiation directly into osteoclasts by an autocrine mechanism in which they produce IL-1 through interaction with bone matrix. TNF could induce c-Fos expression in OCPs at sites of inflammation in bone to promote this autocrine mechanism and thus amplify bone loss.
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Affiliation(s)
- Zhenqiang Yao
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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A new era in prostate cancer therapy: new targets and novel therapeutics. Target Oncol 2007. [DOI: 10.1007/s11523-007-0067-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hu Y, Ek-Rylander B, Karlström E, Wendel M, Andersson G. Osteoclast size heterogeneity in rat long bones is associated with differences in adhesive ligand specificity. Exp Cell Res 2007; 314:638-50. [PMID: 18086469 DOI: 10.1016/j.yexcr.2007.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 11/09/2007] [Accepted: 11/12/2007] [Indexed: 01/15/2023]
Abstract
Prothrombin (PT) is an RGD-containing bone-residing precursor to the serine protease thrombin (TH), which acts as an agonist for a variety of cellular responses in osteoblasts and osteoclasts. We show here that PT, TH, osteopontin (OPN) and fibronectin (FN) promoted adhesion of isolated neonatal rat long bone osteoclasts. However, the cells that adhered to PT and TH were smaller in size, rounded and contained 3-4 nuclei, in comparison to the cells adhering to OPN and FN, which were larger with extended cytoplasmic processes and 6-7 nuclei. Attachment of the larger osteoclasts to OPN and FN was inhibited by antibodies towards beta 3 and beta 1 integrin subunits, respectively. Whereas an RGD-containing peptide inhibited adhesion of the smaller osteoclasts to PT and TH, this was not seen with the beta 3 or beta 1 antibodies. In contrast, the beta 1 antibody augmented osteoclast adhesion to PT and TH in an RGD-dependent manner. Small osteoclasts were less efficient in resorbing mineralized bovine bone slices, as well as expressed lower mRNA levels of MMP-9 and the cathepsins K and L compared to large osteoclasts. The small osteoclast adhering to PT and TH may represent either an immature, less functional precursor to the large osteoclast or alternatively constitute a distinct osteoclast population with a specific role in bone.
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Affiliation(s)
- Yingwei Hu
- Center for Oral Biology, Department of Odontology, Karolinska Institutet, SE-141 04 Huddinge, Sweden
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Bradley DA, Hussain M, Dipaola RS, Kantoff P. Bone Directed Therapies for Prostate Cancer. J Urol 2007; 178:S42-8. [PMID: 17644119 DOI: 10.1016/j.juro.2007.04.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 04/20/2007] [Indexed: 11/29/2022]
Abstract
PURPOSE Bone is the most common site of metastatic disease in prostate cancer and the lead cause of significant morbidity. Preclinical and clinical studies have provided insight into the pathophysiology of bone metastases and the changes that occur in the bone microenvironment that result in a favorable site of growth for prostate cancer. We provide an overview of recent advances in understanding bone biology, and bone targeted therapy research and development. MATERIALS AND METHODS We reviewed recent research findings related to the biology of bone metastases, approaches to targeting osteoclast function, approaches to targeting osteoblasts and advances in assessing the treatment response to bone targeted therapies in the context of prostate cancer management. RESULTS To date targeting some of the key players in the bone microenvironment has not been associated with a significant antitumor effect or with meaningful clinical benefit in phase III randomized trials. A significant limitation in the development of bone targeted therapy has been the inability to objectively assess treatment response. Investigation of improved imaging techniques are ongoing to provide better treatment assessment and, therefore, allow more rapid drug screening and development. CONCLUSIONS It is our recommendation that future therapy development should be combination based, focusing on simultaneous targeting of multiple relevant pathways. Most important of all is the direct targeting of prostate cancer cells.
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Affiliation(s)
- Deborah A Bradley
- Division of Hematology and Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
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Furlan F, Galbiati C, Jorgensen NR, Jensen JEB, Mrak E, Rubinacci A, Talotta F, Verde P, Blasi F. Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function. J Bone Miner Res 2007; 22:1387-96. [PMID: 17539736 DOI: 10.1359/jbmr.070516] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The uPAR and its ligand uPA are expressed by both osteoblasts and osteoclasts. Their function in bone remodeling is unknown. We report that uPAR-lacking mice display increased BMD, increased osteogenic potential of osteoblasts, decreased osteoclasts formation, and altered cytoskeletal reorganization in mature osteoclasts. INTRODUCTION Urokinase receptor (uPAR) is actively involved in the regulation of important cell functions, such as proliferation, adhesion, and migration. It was previously shown that the major players in bone remodeling, osteoblasts and osteoclasts, express uPAR and produce urokinase (uPA). The purpose of this study was to investigate the role of uPAR in bone remodeling. MATERIALS AND METHODS In vivo studies were performed in uPAR knockout (KO) and wildtype (WT) mice on a C57Bl6/SV129 (75:25) background. Bone mass was analyzed by pQCT. Excised tibias were subjected to mechanical tests. UPAR KO calvaria osteoblasts were characterized by proliferation assays, RT-PCR for important proteins secreted during differentiation, and immunoblot for activator protein 1 (AP-1) family members. In vitro osteoclast formation was tested with uPAR KO bone marrow monocytes in the presence of macrophage-colony stimulating factor (M-CSF) and RANKL. Phalloidin staining in osteoclasts served to study actin ring and podosome formation. RESULTS pQCT revealed increased bone mass in uPAR-null mice. Mechanical tests showed reduced load-sustaining capability in uPAR KO tibias. uPAR KO osteoblasts showed a proliferative advantage with no difference in apoptosis, higher matrix mineralization, and earlier appearance of alkaline phosphatase (ALP). Surface RANKL expression at different stages of differentiation was not altered. AP-1 components, such as JunB and Fra-1, were upregulated in uPAR KO osteoblasts, along with other osteoblasts markers. On the resorptive side, the number of osteoclasts formed in vitro from uPAR KO monocytes was decreased. Podosome imaging in uPAR KO osteoclasts revealed a defect in actin ring formation. CONCLUSIONS The defective proliferation and differentiation of bone cells, coincident with both aberrant expression of transcription factors and cytoskeletal organization, are typical uPAR-dependent molecular phenotypes, and we have now shown their function in osteoblasts and osteoclasts function in vivo.
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Affiliation(s)
- Federico Furlan
- H San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Department of Molecular Biology and Functional Genomics, Milan, Italy
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Schneider D, Liaw L, Daniel C, Athanasopoulos AN, Herrmann M, Preissner KT, Nawroth PP, Chavakis T. Inhibition of breast cancer cell adhesion and bone metastasis by the extracellular adherence protein of Staphylococcus aureus. Biochem Biophys Res Commun 2007; 357:282-8. [PMID: 17418809 PMCID: PMC1913187 DOI: 10.1016/j.bbrc.2007.03.143] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 03/22/2007] [Indexed: 01/04/2023]
Abstract
Bone metastasis is a common sequelae of breast cancer and the interaction of alpha v beta3-integrin with osteopontin (OPN) found in the extracellular matrix of mineralized tissues is implicated in this process. The integrin-dependent proadhesive and promigratory functions of OPN are particularly attributed to the 40 kD N-terminal fragment that derives upon matrix metalloproteinase (MMP) cleavage. Based on the broad repertoire of interactions between Staphylococcus aureus extracellular adherence protein (Eap) and host components, we here characterized Eap to specifically interact with recombinant full-length OPN and the 40 kD N-terminal MMP cleavage fragment, but not with the 32 kD or the 25 kD C-terminal fragments of OPN. Eap thereby prevented the OPN/alpha v beta3-integrin interaction, as well as the alpha v beta3-integrin-dependent adhesion of MDA-MB-231 breast cancer cells to full-length OPN or to the 40 kD fragment and the migration of these cells towards OPN. Furthermore, Eap treatment markedly impaired the development of osseous metastasis of human MDA-MB-231 cells in vivo. Taken together, Eap may represent an attractive novel treatment for the prevention of breast cancer bone metastasis.
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Affiliation(s)
- Darius Schneider
- Department of Internal Medicine, University Heidelberg, D-69120 Heidelberg, Germany
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