heparitin-sulfate and Bone-Neoplasms

Frequent benign outgrowths from bone known as osteochondromas, exhibiting typical endochondral ossification, are reported from single to multiple lesions. Characterised by a high incidence of osteochondromas and skeletal deformities, multiple hereditary exostoses (MHE) is the most common inherited musculoskeletal condition. While factors for severity remain unknown, mutations in exostosin 1 and exostosin 2 genes, encoding glycosyltransferases involved in the biosynthesis of ubiquitously expressed heparan sulphate (HS) chains, are associated with MHE. HS-binding bone morphogenetic proteins (BMPs) are multifunctional proteins involved in the morphogenesis of bone and cartilage. HS and HS proteoglycans are involved in BMP-mediated morphogenesis by regulating their gradient formation and activity. Mutations in exostosin genes disturb HS biosynthesis, subsequently affecting its functional role in the regulation of signalling pathways. As BMPs are the primordial morphogens for bone development, we propose the hypothesis that BMP signalling may be critical in osteochondromas. For this reason, the outcomes of exostosin mutations on HS biosynthesis and interactions within osteochondromas and MHE are reviewed. Since BMPs are HS binding proteins, the interactions of HS with the BMP signalling pathway are discussed. The impact of mouse models in the quest to better understand the cell biology of osteochondromas is discussed. Several challenges and questions still remain and further investigations are needed to explore new approaches for better understanding of the pathogenesis of osteochondromas.

Topics: Animals; Bone Morphogenetic Proteins; Bone Neoplasms; Disease Models, Animal; Heparitin Sulfate; Humans; Mice; Mutation; N-Acetylglucosaminyltransferases; Osteochondroma; Signal Transduction

This review summarizes a series of studies demonstrating that heparan sulfate proteoglycans act to promote the growth and metastasis of myeloma and breast tumors, two tumors that home to, and grow within, bone. Much of the growth-promoting effect of proteoglycans in these tumors may reside in the shed form of syndecan-1 that acts to favorably condition the tumor microenvironment. Moreover, the interplay between heparan sulfate and the extracellular enzyme heparanase-1 also has important regulatory implications. Recent studies indicate that the activity of heparanase, which likely releases heparin sulfate-bound growth factors and generates highly active heparan sulfate fragments, also promotes growth and metastasis of myeloma and breast tumors. Understanding the role of heparan sulfate and heparanase in the regulation of tumor behavior may lead to new therapeutic approaches for treating cancer.

Topics: Animals; Bone Neoplasms; Breast Neoplasms; Cell Proliferation; Glucuronidase; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Models, Biological; Multiple Myeloma; Neoplasm Metastasis; Osteolysis

The osteochondroma is a common, benign, primary tumor of bone. A mechanism for its pathogenesis has not been identified, but loss of function of EXT genes is implicated in sporadic and hereditary multiple osteochondromas. Recent advances in the understanding of other molecular signaling pathways in the physis cast doubt on the latest pathogenetic theories. These advances are reviewed and used as the basis for a revised theory for pathogenesis: A clone of proliferating chondrocytes without functional EXT1 (or EXT2) expression fails to produce heparan sulfate; lack of heparan sulfate at the cell surface disrupts fibroblast growth factor signaling and Indian hedgehog diffusion, leading to focal overproliferation and adjacent bone collar deficiency, respectively; together these effects are proposed to contribute to osteochondroma pathogenesis.

Topics: Bone Neoplasms; Fibroblast Growth Factors; Genes, Tumor Suppressor; Hedgehog Proteins; Heparitin Sulfate; Humans; N-Acetylglucosaminyltransferases; Osteochondroma; Signal Transduction; Trans-Activators

Topics: Acetylglucosamine; Adult; Animals; Biopolymers; Bone Development; Bone Neoplasms; Cartilage; Child; CHO Cells; Cricetinae; DNA Mutational Analysis; Evolution, Molecular; Exostoses, Multiple Hereditary; Genes, Dominant; Genes, Lethal; Genes, Tumor Suppressor; Genetic Complementation Test; Genetic Predisposition to Disease; Glucuronic Acid; Glycosylation; Heparitin Sulfate; Humans; Invertebrates; Macromolecular Substances; Mice; Mice, Knockout; Models, Biological; N-Acetylglucosaminyltransferases; Parathyroid Hormone-Related Protein; Proteins; Receptor, Parathyroid Hormone, Type 1; Receptors, Parathyroid Hormone; Risk; Structure-Activity Relationship; Vertebrates

Bone development is a highly regulated process sensitive to a wide variety of hormones, inflammatory mediators and growth factors. One of the most common hereditary skeletal dysplasias, hereditary multiple exostoses (HME), is an autosomal dominant disorder characterized by skeletal malformations that manifest as bony, benign tumours near the end of long bones. HME is usually caused by defects in either one of two genes, EXT1 and EXT2, which encode enzymes that catalyse the biosynthesis of heparan sulphate, an important component of the extracellular matrix. Thus, HME-linked bone tumours, like many other skeletal dysplasias, probably result from disruptions in cell surface architecture. However, despite the recent success in unravelling functions for several members of the EXT gene family, significant challenges remain before this knowledge can be used to develop new approaches for the diagnosis and treatment of disease.

Topics: Aged; Animals; Biglycan; Bone Development; Bone Neoplasms; Chromosomes, Human, Pair 8; Exostoses, Multiple Hereditary; Extracellular Matrix Proteins; Female; Genes, Tumor Suppressor; Genetic Predisposition to Disease; Hedgehog Proteins; Heparitin Sulfate; Humans; Langer-Giedion Syndrome; Loss of Heterozygosity; Male; Mice; Mice, Knockout; N-Acetylglucosaminyltransferases; Parathyroid Hormone-Related Protein; Proteins; Proteoglycans; Trans-Activators

Hereditary multiple exostoses (HME) is a rare, pediatric disorder characterized by osteochondromas that form along growth plates and provoke significant musculoskeletal problems. HME is caused by mutations in heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. Seemingly paradoxically, osteochondromas were found to contain excessive extracellular heparanase (Hpse) that could further reduce HS levels and exacerbate pathogenesis. To test Hpse roles, we asked whether its ablation would protect against osteochondroma formation in a conditional HME model consisting of mice bearing floxed Ext1 alleles in Agr-CreER background (Ext1

Topics: Animals; Bone Neoplasms; Child; Disease Models, Animal; Exostoses, Multiple Hereditary; Glucuronidase; Heparitin Sulfate; Humans; Mice; Mutation; N-Acetylglucosaminyltransferases; Osteochondroma; Retinoids; Tamoxifen; X-Ray Microtomography

Multiple osteochondromas (MO) is a hereditary disorder associated with benign cartilaginous tumors, known to be characterized by absence or highly reduced amount of heparan sulfate (HS) in the extracellular matrix of growth plate cartilage, which alters proper signaling networks leading to improper bone growth. Although recent studies demonstrated accumulation of HS in the cytoplasm of MO chondrocytes, nothing is known on the structural alterations which prevent HS from undergoing its physiologic pathway. In this work, osteochondroma (OC), peripheral chondrosarcoma, and healthy cartilaginous human samples were processed following a procedure previously set up to structurally characterize and compare HS from pathologic and physiologic conditions, and to examine the phenotypic differences that arise in the presence of either exostosin 1 or 2 (

Topics: Adolescent; Adult; Bone Neoplasms; Cartilage; Child; Child, Preschool; Chondrosarcoma; Chromatography, High Pressure Liquid; Female; Heparitin Sulfate; Humans; Magnetic Resonance Imaging; Mass Spectrometry; Mutation; N-Acetylglucosaminyltransferases; Osteochondroma

Insulin plays a wide variety of physiological actions in osteoblast cells such as differentiation and gene expression. Integrins are transmembrane heterodimeric proteins consisting of α and β subunits which transduce signals from extracellular matrix into the cell. The integrin-mediated signals regulate gene expression, differentiation and survival of osteoblast. In the present study, we explored to determine if insulin could regulate integrin-linked kinase (ILK) signaling in osteoblast like UMR-106 cells. Insulin rapidly stimulated ILK activity in a time-dependent manner with maximal activity observed at 60 min. The insulin's ability to stimulate ILK was almost completely abolished when the cells were pre-incubated with heparinase III (HepIII), suggesting the heparan sulfates attached to syndecan-1 play an important role in the activation of ILK in response to insulin. Interestingly, insulin also activated Akt activity by phosphorylation, whereas pre-treatment of HepIII failed to interfere Akt activation by insulin. In contrast, HepIII pre-treatment inhibited alkaline phosphatase stimulation and collagen synthesis in response to insulin. These results strongly suggest that heparan sulfates on the syndecan-1 and/or shedding of syndecan-1 play a significant role in regulating ILK by insulin, and thereby regulating alkaline phosphatase and collagen synthesis in osteoblast cells.

Topics: Animals; Blotting, Western; Bone Neoplasms; Cell Differentiation; Heparitin Sulfate; Hypoglycemic Agents; Insulin; Osteosarcoma; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Syndecan-1; Tumor Cells, Cultured

On October 29, 2009, researchers and physicians gathered at the Sheraton Four Points Hotel in Boston for 4 days to discuss a disease called multiple hereditary exostoses (MHE). MHE is an autosomal dominant disease that is associated with mutations in two enzymes that are required for heparan sulfate (HS) synthesis. Children with the disease form numerous benign bone tumors (osteochondromas) and have >2% chance of developing chondrosarcoma. The aim of the meeting was to generate new ideas for the diagnoses, treatment, and cure of this disease. Discussions ranged from orthopedic surgical treatment and patients' personal experiences to fundamental questions in skeletal biology and the precise molecular role that HS plays in developmental signaling pathways.

Topics: Bone and Bones; Bone Neoplasms; Boston; Carbohydrates; Child; Chondrosarcoma; Exostoses, Multiple Hereditary; Heparitin Sulfate; Humans; Mutation; Osteochondroma

Chondrosarcomas are malignant cartilage-forming tumors arising centrally in bone (central chondrosarcoma) or within the cartilaginous cap of osteochondroma (peripheral chondrosarcoma). For hereditary multiple osteochondromas, two responsible genes, EXT1 and EXT2, have been cloned. Their recently elucidated role in heparan sulfate biosynthesis and Hedgehog diffusion leads to the hypothesis that EXT inactivation affects fibroblast growth factor (FGF) and Indian Hedgehog (IHh)/parathyroid hormone-related peptide (PTHrP) signaling, two important pathways in chondrocyte proliferation and differentiation. The expression of PTHrP, PTHrP-receptor, Bcl-2, FGF2, FGFR1, FGFR3, and p21 is investigated by immunohistochemistry in osteochondromas (n = 24) and peripheral (n = 29) and central (n = 20) chondrosarcomas. IHh/PTHrP and FGF signaling molecules are mostly absent in osteochondromas. Although no somatic EXT mutations were found in sporadic osteochondromas, the putative EXT downstream targets are affected similarly in sporadic and hereditary tumors. In chondrosarcomas, re-expression of FGF2, FGFR1, PTHrP, Bcl-2, and p21 is found. Expression levels increase with increasing histological grade. Up-regulation of PTHrP and Bcl-2 characterizes malignant transformation of osteochondroma because PTHrP and Bcl-2 expression is significantly higher in borderline and grade I peripheral chondrosarcomas compared with osteochondromas. In contrast, up-regulation of PTHrP and Bcl-2 seems to be a late event in central cartilaginous tumorigenesis because expression is mainly restricted to high-grade central tumors.

Topics: Adolescent; Adult; Aged; Bone Neoplasms; Child; Child, Preschool; Chondrosarcoma; Cloning, Molecular; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Disease Progression; Female; Fibroblast Growth Factor 2; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Heparitin Sulfate; Humans; Male; Middle Aged; N-Acetylglucosaminyltransferases; Osteochondroma; Parathyroid Hormone-Related Protein; Proteins; Proto-Oncogene Proteins c-bcl-2; Receptor Protein-Tyrosine Kinases; Receptor, Fibroblast Growth Factor, Type 1; Receptors, Fibroblast Growth Factor

Viscous material secreted from NMSG 10 cells cultured from malignant fibrous histiocytoma of human bone was demonstrated using two-dimensional electrophoresis to be glycosaminoglycans (GAGs) consisting of mainly hyaluronic acid (HA), along with small amounts of heparan sulfate (HS) and chondroitin sulfate (ChS). The biosynthesis of HA in a cell-free system was located at the plasma membrane fraction by colloidal-iron-reactive ultrastructural staining. The molecular weight of the HA synthesized by the plasma membrane fraction was estimated to be about 90,000 D by gel filtration. The material secreted by the original tumor tissue of NMSG 10 cells was demonstrated to be GAGs consisting of HA, HS, ChS and dermatan sulfate using two-dimensional electrophoresis. These findings suggest that transformed tumor cells could synthesize HA at the plasma membrane and release it into the stroma of tumor tissue.

Topics: Alcian Blue; Bone Neoplasms; Cell Membrane; Cell-Free System; Chondroitin Sulfates; Dermatan Sulfate; Heparitin Sulfate; Histiocytoma, Benign Fibrous; Humans; Hyaluronic Acid; Hyaluronoglucosaminidase; Staining and Labeling; Tumor Cells, Cultured

Bone resorption resulting from the metastatic human melanoma cell line (A375) was investigated morphologically using an experimental model of bone metastases in nude mice. An injection of A375 (1 x 10(5)) in the left ventricle produced multiple osteolytic lesions. Many TRAPase-positive multinucleated cells, identified by EM as osteoclasts, were observed on the bone surface at the site of metastases. The findings suggest that bone resorption was caused by osteoclasts developed in the presence of tumor cells. Even where tumor cells were juxtaposed to bone surface, small and flat TRAPase-positive cells were shown to exist on the bone surface. Thus, bone resorption was mainly associated with the occurrence of osteoclasts. A large number of osteoclast progenitor cells were also observed adjacent to tumor cells and/or stromal cells located apart from bone, indicating possible participation of tumor cells and/or stromal cells in the differentiation of osteoclasts. Ultrastructurally, stromal cells and/or extracellular matrices were present between tumor cells and osteoclast progenitor cells. Immunohistochemical observation clarified the localization of heparan sulfate proteoglycan (HSPG) and fibronectin (FN) around osteoclast progenitor cells. These findings suggest that they play an important role in providing a microenvironment favorable for osteoclast differentiation and activation. The immunohistochemical localization of IL-6, PGE2, and TGF-alpha also indicates that they are involved in osteoclast differentiation and activation. In conclusion, bone resorption at the metastatic sites of A375 is mediated via osteoclasts and A375 cells may be involved in the differentiation and activation of osteoclasts in association with stromal cells, extracellular matrices (HSPG, FN) and osteotropic cytokines (IL-6, PGE2, TGF-alpha).

Topics: Acid Phosphatase; Animals; Bone Neoplasms; Bone Resorption; Cell Differentiation; Dinoprostone; Disease Models, Animal; Fibronectins; Giant Cells; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Immunohistochemistry; Interleukin-6; Male; Melanoma, Amelanotic; Mice; Mice, Inbred BALB C; Mice, Nude; Microscopy, Electron; Osteoclasts; Proteoglycans; Stem Cells; Stromal Cells; Transforming Growth Factor alpha; Tumor Cells, Cultured