Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The met oncogene activated in vitro by treatment of a human osteogenic sarcoma (HOS) cell line with N-methyl-N'-nitronitrosoguanidine (MNNG) is related to the tyrosine kinase gene family. Probes from the met oncogene locus recognize two distinct transcripts of 9.0 kb and 10.0 kb which are independently expressed in a cell-type-specific fashion. While the met proto-oncogene locus expresses the 9.0 kb RNA and maps to human chromosome 7q21-31, the locus expressing the 10.0 kb RNA, (tpr; translocated promoter region) maps to human chromosome 1. Both MNNG-HOS cells and met NIH 3T3 transformants express a novel 5.0 kb RNA which represents a hybrid transcript with 5' sequences derived from tpr and 3' sequences from the met proto-oncogene. Treating HOS cells in vitro with MNNG, a known clastogenic carcinogen, resulted in fusion of two chromosomally disparate loci, met and tpr, generating the active met oncogene.
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PMID:Mechanism of met oncogene activation. 242 52

Prolonged exposure of a nontumorigenic human osteogenic sarcoma cell line (HOS) with the direct acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) gave rise to morphologically transformed cells which were tumorigenic in nude mice and termed MNNG-HOS. We have shown that DNA from MNNG-HOS cells will transform NIH/3T3 cells and have isolated greater than 35 kb of human DNA containing an oncogene, termed met. The activated met oncogene expresses a novel 5.0 kb RNA transcript which is a hybrid RNA derived from a DNA rearrangement involving two distinct genetic loci termed met and tpr (translocated promoter region). The met proto-oncogene has been localized to 7q21-q31 by in situ hybridization. This locus expresses a 9.0 kb RNA in fibroblast and epithelial cell lines, but is not commonly expressed in cell lines derived from the hematopoietic cell lineage. In contrast, the tpr locus is on chromosome 1, and expresses a 10.0 kb RNA in all human cell lines tested. The novel 5.0 kb met oncogene RNA is 3' co-terminal with the 9.0 kb met proto-oncogene RNA, while the 5' portion of this RNA uses at least two exons derived from the 10.0 kb tpr RNA. These exons are small and are presumably in the promoter region of both tpr and tpr-met transcripts. Nucleotide sequence analysis of the 3' end of met shows that it is a member of the tyrosine kinase family of genes. Peptide antibody to the C-terminal coding region of met immunoprecipitates a 65 kilodalton (kd) polypeptide (p65) in both MNNG-HOS cells and met transformed NIH/3T3 cells. This product also has tyrosine kinase activity in vitro and is presumed to correspond to the tpr-met product. The same antibody detects three larger met-related polypeptides of 160, 140, and 110 kd in human fibroblasts and epithelial cells by in vivo labeling with [35S]methionine. However, only one of the three met proto-oncogene polypeptides, p140, appears to be phosphorylated in the in vitro kinase assay. High levels of in vitro 32P incorporation into p140 met are observed in 4 out of 30 human epithelial cancer cell lines tested. Activation of the met oncogene in MNNG-HOS cells results from a DNA rearrangement possibly mediated in vitro by MNNG. The mode of activation of met may therefore be similar to the epidermal growth factor (EGF)R/v-erbB oncogene; or the bcr/c-abl rearrangement present in the Philadelphia chromosome translocation which is found in chronic myelogenous leukemias.
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PMID:The human met oncogene is a member of the tyrosine kinase family. 333 11

Overexpression of the hepatocyte growth factor receptor (Met/HGF receptor), a transmembrane tyrosine kinase encoded by the met proto-oncogene, has been associated with tumor progression in different human carcinomas. More recently, the Met/HGF receptor has also been described in tumor cell lines of mesenchymal origin, suggesting the existence of an autocrine loop that may contribute to the pathogenesis of sarcomas. In this study, we analyzed the expression of Met/HGF receptor by Western blotting and immunohistochemistry in frozen samples of 87 primary tumors of bone and soft tissues. Among benign tumors, overexpression was consistently found only in giant-cell tumor, a locally aggressive lesion that may also, although rarely, spread to the lung. Among malignant lesions, the presence of the Met/HGF receptor was detected in a relevant percentage of primaries and in almost all of the recurrences. The highest levels of Met/HGF receptor were found in osteosarcoma, a highly aggressive tumor that typically permeates the host bone and rapidly expands to the soft tissues. On the contrary, only low levels of Met/HGF receptor were found in chondrosarcoma, a slowly growing tumor that usually expands without massive destruction of the surrounding structures. These data indicate an association of Met/HGF expression with local aggressiveness in human mesenchymal tumors. The finding of Met/HGF receptor overexpression in all of the osteosarcomas suggests a role for the met proto-oncogene in the pathogenesis of this tumor.
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PMID:Expression of Met/hepatocyte growth factor receptor gene and malignant behavior of musculoskeletal tumors. 886 70

The expression of c-met proto-oncogene product (c-MET) has been reported to be related to invasive growth or tumor stage in some tumors, but little is known concerning the significance of c-MET expression in bone tumors. With use of formalin-fixed, paraffin-embedded tissue specimens and polyclonal antibody for c-MET, we studied the expression of c-MET in 122 cases of malignant bone tumors (43 osteosarcomas, 24 chondrosarcomas, 21 malignant fibrous histiocytomas of bone, 16 Ewing's sarcoma versus primitive neuroectodermal tumors, 18 chordomas), 65 cases of benign tumors and tumor-like lesions (including 8 giant cell tumors of bone, 8 chondroblastomas, 12 enchondromas, 7 osteochondromas, 10 fibrous dysplasias), 7 cases of articular cartilaginous tissue, and 10 cases of fetal vertebral tissue consisting of foci of enchondral ossification and notochordal tissue. In malignant tumors, c-MET expression was most frequently detected in chordoma (94.4%), followed by chondrosarcoma (54.2%) and osteosarcoma (23.3%). Among the osteosarcoma specimens, c-MET expression was frequently detected in the chondroblastic subtype (66.7%), but the incidence was low in the cases with other subtypes of osteosarcoma. We found no significant correlation between the c-MET expression and the histologic grade of malignancy in either osteosarcoma or chondrosarcoma. c-MET expression was either rarely observed or completely negative in malignant fibrous histiocytomas of bone (4.8%) and primitive neuroectodermal tumors (0%). In benign tumors and tumor-like lesions, c-MET expression was frequently detected in cartilaginous tumors, such as chondroblastoma (62.5%), enchondroma (66.7%), and osteochondroma (71.4%), but no expression was observed in giant cell tumors of bone or any other benign tumors or tumor-like lesions. In normal tissue, c-MET expression was frequently detected in the articular cartilage (100%) and notochord (70.0%) specimens examined. We conclude that c-MET expression as frequent as that observed in the notochordal tissue, chordomas, articular cartilage, and cartilaginous tumors is related to the development of both normal tissue and chondroid tumors.
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PMID:Expression of c-met proto-oncogene product (c-MET) in benign and malignant bone tumors. 926 27

MicroRNA-1 (miR-1) has been shown to function as a critical gene regulator in multiple types of cancers. However, the role of miR-1 in osteosarcoma has not been totally clarified. In the present study, we investigated the effects of miR-1 on osteosarcoma and the underlying mechanism. We found that miR-1 was downregulated in osteosarcoma tissues and osteosarcoma cell lines. Restoration of miR-1 significantly suppressed osteosarcoma cell proliferation by inhibiting cell cycle progression. Mediator complex subunit 1 (Med1) and 31 (Med31) were validated as targets of miR-1 in osteosarcoma by luciferase reporter assay. Downregulation of Med1 and Med31 suppressed the proliferation of osteosarcoma cells, and overexpression of Med1 and Med31 abrogated the effects of miR-1 on cell proliferation. Furthermore, both miR-1 and knockdown of Med1 or Med31 reduced the expression of met proto-oncogene (MET) and blocked the downstream signaling of MET responding to hepatocyte growth factor (HGF). Taken together, the findings of this study suggest that Med1 and Med31 serve as potential gene therapeutic targets in osteosarcoma and miR-1 may prove to be a promising agent.
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PMID:MicroRNA-1 functions as a potential tumor suppressor in osteosarcoma by targeting Med1 and Med31. 2496 80