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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Saos-2 cultured human osteosarcoma cells contain an extractable bone inducing agent that can induce heterotopic bone in the muscle of Nu/Nu mice. A semipurified GuHCl extract of Saos-2 cells also can promote healing and complete bony union in otherwise non-healing surgically induced defects of rat femur. Northern blot analyses indicate expression of mRNAs for bone morphogenetic proteins (BMP)-1, 2, 3, 4, 6 and transforming growth factor beta (TGF beta) in Saos-2 cells, and BMP-2, 3, 4, 5, 7 and TGF beta in nonosteoinductive U20S human osteosarcoma cells. Saos-2 cells exceeded U20S cells in expression levels of BMP-1, 3, 4 and TGF beta, whereas U20S cells expressed higher levels of BMP-2, 6 and also expressed trace amounts of BMP-5 and 7 not seen in Saos-2 cells. The authors hypothesize that Saos-2 cells contain an optimal admixture of known bone growth factors plus possible other unknown components that, acting alone or in combination with bone morphogenetic protein and/or TGF beta, can induce bone. Although bone inducing agent-induced heterotopic bones have half lives of only a few weeks, the reparative bone induced by bone inducing agent in femoral defects gives every indication of being permanent and self-sustaining. This suggests a fundamental difference between heterotopic and orthotopic osteoprogenitor cells with those involved in orthotopic bone repair more closely resembling the committed or determined osteoprogenitor cells of marrow as described by Friedenstein.
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PMID:The mechanism of bone induction and bone healing by human osteosarcoma cell extracts. 764 70

Freeze-dried Saos-2, human osteosarcoma cells, and extracts of Saos-2 cells contain all components necessary to induce ectopic new bone and marrow when implanted into athymic Nu/Nu nuce. On the other hand, human osteosarcoma cells of the U-2 OS strain failed to induce bone formation under the same experimental conditions. Our aim was to compare the relative expressions of known osteoinductive factors including bone morphogenetic proteins (BMPs) and transforming growth factor-beta (TGF-beta) in these two cell lines in an attempt to explain the unique bone-inducing ability of the Saos-2 cells. Saos-2 cells expressed mRNA for BMP-1, -2, -3, -4,-6, and TGF-beta 1. The non-osteoinductive U-2 OS cells expressed BMP-2, -4, -5, -6, and -7 as well as TGF-beta 1 mRNA, while levels of BMP-1 and BMP-3 mRNA were either not detectable or detectable at a very low level in U-2 OS cells. The presence of BMP-1 and -4 protein was confirmed in Saos-2 cells by immunofluorescence, and TGF beta protein was demonstrated by bioassay in both cell types. These findings suggest that Saos-2 cells are endowed qualitatively and quantitatively with sufficient amounts of many bone morphogenetic proteins-especially BMP-1, -3, and -4-to confer osteoinductivity upon these cells. However, the absence of osteoinductivity in U-2 OS cells, despite significant mRNA expression levels of several bone morphogenetic proteins, suggests that, even though expression of one or more bone morphogenetic proteins may be present, it may not necessarily be sufficient to confer osteoinductivity upon U-2 OS cells. U-2 OS cells may be non-osteoinductive because (1) they contain inhibitors to the BMPs or secrete inhibitory binding proteins, (2) they do not process BMPs correctly, or (3) the BMPs are inappropriately localized and sequestered within the U-2 OS cells. Saos 2 cells may be osteoinductive because (1) they uniquely express BMP-1, (2) they express an appropriate combination of interactive BMPs at appropriate levels, and/or (3) the Saos-2 cells elaborate as-yet-unidentified osteoinductive factor(s).
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PMID:Expression of bone morphogenetic proteins by osteoinductive and non-osteoinductive human osteosarcoma cells. 887 5

Maximum collagen synthesis and maximum accumulation of insoluble collagen occur at different phenotypic stages in developing osteoblastic cell cultures. Insoluble collagen accumulation depends in part on the activity of extracellular enzymes including procollagen N-proteinases, procollagen C-proteinase (derived from the BMP1 gene), and lysyl oxidase. In addition to its action on procollagen, procollagen C-proteinase processes prolysyl oxidase to mature 32-kDa lysyl oxidase. The regulation of extracellular activities that control insoluble collagen accumulation has not been studied extensively. The present study compares molecular events that control production of a collagenous mineralized extracellular matrix in vitro among five different murine osteosarcoma cell clones derived from the same tumor, but which differ in their ability to produce an insoluble mineralized matrix. Levels of insoluble type I collagen, insoluble calcium, bone morphogenetic protein 1 (BMP-1), and lysyl oxidase expression, lysyl oxidase biosynthesis, lysyl oxidase activity, and prolysyl oxidase processing activity were determined. Results surprisingly indicate that lysyl oxidase activity is not related closely to lysyl oxidase messenger RNA (mRNA) levels among the different cell clones. However, it appears that BMP-1-dependent prolysyl oxidase processing could contribute to the observed lysyl oxidase activity. Highest collagen and BMP-1 mRNA levels, prolysyl oxidase processing activity, and lysyl oxidase activity occurred in a cell clone (K8) that showed the highest levels of insoluble collagen accumulation. Culture media from a cell clone (K37) that accumulates little insoluble collagen or calcium but expresses high levels of lysyl oxidase mRNA contained low molecular weight fragments of lysyl oxidase protein and showed low lysyl oxidase activity. By contrast the K14 cell line exhibits relatively high lysyl oxidase activity and collagen accumulation, but low levels of mature lysyl oxidase protein. Together, these studies indicate that catabolic as well as anabolic activities are important in regulating insoluble collagen accumulation in osteoblastic cells. In addition, results suggest that products of genes homologous to lysyl oxidase may contribute to observed lysyl oxidase activity.
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PMID:Molecular events that contribute to lysyl oxidase enzyme activity and insoluble collagen accumulation in osteosarcoma cell clones. 1084 Nov 88

In addition to osteosarcomas some epithelial tumors also show bone induction, which is supposedly due to bone morphogenetic proteins (BMPs). However, the types of BMPs expressed in different kinds of tumors have not been studied extensively. In this study five human osteosarcoma and six human carcinoma cell lines were examined to investigate the bone induction and BMP mRNA expression. The cultured cells were transplanted in the subcutaneous tissue of athymic nude mice with or without diffusion chambers. Reverse transcription-polymerase chain reaction (RT-PCR) was used for the detection of BMP mRNAs. All osteosarcoma cell lines expressing all BMPs (BMP-1 to 7) examined, successfully formed bone or osteoid tissue irrespective of the use of a diffusion chamber. Bone formation was induced by diffusion chamber in an osteosarcoma cell line OST and a gastric adenocarcinoma cell line MKN45. OST cells lacked BMP-3 and 7, and MKN45 cells lacked BMP-3, 5 and 6. Our data suggest that BMP-3, 5, 6 and 7 are not always essential for bone induction in tumor cells.
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PMID:Expression of bone morphogenetic proteins in human osteogenic and epithelial tumor cells. 1084 44

An ability to induce new bone formation at a required site would represent a considerable advance in bone repair and tissue engineering. It has been shown that the healing of critical-size bone defects in rats can be augmented by extracts of Saos-2 cells. These human osteosarcoma cells uniquely contain a bone-inducing activity, whereas other human osteosarcoma cells, e.g., U-2 OS cells, cannot replicate the osteoinductive capacity. To understand the necessary components of the Saos-2 bone-inducing activity, this study compared osteoinductive Saos-2 cells with non-osteoinductive U-2 OS cells with respect to the synthesis of bone morphogenetic proteins (BMPs)-1, -2, -3, -4, -5, -6, and -7 and the non-collagenous matrix proteins bone sialoprotein (BSP), osteonectin (ON), osteopontin (OPN), and osteocalcin (OC). The main differences were abundant synthesis of BMP-1/tolloid, BMP-3, -4, and BSP by Saos-2 cells, but absence or reduced synthesis in U-2 OS cells. BMP-2 and -7 were present in low amounts in both cell types, while BMP-5 and -6 were more abundant in U-2 OS cells, suggesting that these BMPs were of lesser importance for the osteoinductivity of Saos-2 cells. However, a relatively high expression of BMP-3 and -4, together with BMP-1/tolloid, may be important for the osteoinductive capacity of Saos-2 cells. The inability of U2-OS cells to induce bone, despite expressing most of the BMPs, may be due to an insufficiency of tolloid, BMP-3 or -4, BSP, and/or other unknown factors. A better understanding of the necessary components of the Saos-2 cell bone-inducing agent may, in future, lead to clinically useful Saos-2 cell products for bone repair and tissue engineering.
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PMID:Selective synthesis of bone morphogenetic proteins-1, -3, -4 and bone sialoprotein may be important for osteoinduction by Saos-2 cells. 1186 28

Musculoskeletal malignancy is often accompanied by aberrant bone remodeling, leading to tumor cell invasion into skeletal tissues and causing severe pain. BMPs, FGF-2, and RANKL have been identified as promising regulators in physiological bone remodeling. In this study, we explored the expressional profile of BMPs, FGF-2, and RANKL in 1361 patients with 22 varieties of musculoskeletal tumors. Notably, the expression of FGF-2 and RANKL was under detected in all patients. Among BMP-1 to BMP-15, we found that BMP-1, -2, -4, -5, -6, and -7 were prevalent. In comparison with normal bones, osteosarcoma highly expressed BMP-1, -2, -4, and -7 with statistical significance. Synovial sarcoma upregulated BMP-4, -5, and -7; rhabdomyosarcoma increased BMP-1 and -4; and alveolar soft part sarcoma upregulated BMP-1, -4, and -7. To visualize the BMP-oriented interactions in a bone tumor microenvironment, we have developed novel software that analyzes numerous cell-to-cell and ligand-to-receptor interactions, i.e., Environmentome, delineating that osteosarcoma-secreted BMP-4 and synovial sarcoma-secreted BMP-7 potently interact with osteoblasts, osteocytes, osteoclast precursors, and mature osteoclasts. Specifically, quantification analysis revealed that the relationship between osteosarcoma and mature osteoclast/precursor, BMP4-BMPR2 and BMP4-ACVR2A interactions were most potent. Regarding the association between osteosarcoma and osteocyte/osteoblast, BMP4-ACVR1 and BMP4-BMPR2 were the key interactions. In the connection between synovial sarcoma and mature osteoclast/precursor, BMP7-ACVR2A and BMP7-BMPR2 interactions were most remarkable. With regard to the cellular link between synovial sarcoma and osteocyte/osteoblast, BMP7-BMPR2 was identified as a potent interaction. In conclusion, our new outlook suggests delivering the pathological events clinically underlie behind severe skeletal pain or fracture in musculoskeletal tumors. This article is protected by copyright. All rights reserved.
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PMID:Molecular profiling of bone remodeling occurring in musculoskeletal tumors. 3303 13