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

Two uncommon tumors of the head and neck first revealed primary roles for two classes of cancer genes (oncogenes, tumor suppressor genes) in the origin of human cancer. In Burkitt's lymphoma the initiating event is a chromosomal translocation that leads to unregulated expression of an oncogene (MYCC), whereas retinoblastoma involves loss of function of both copies of a tumor suppressor gene (RB1). In osteosarcoma the RB1 gene is often affected, as is the gene (TP53) that codes for the p53 protein. TP53 is frequently mutated in carcinomas of the head and neck, as in one of the ras oncogenes. Multiple genetic changes typify carcinomas. Some carcinomas of the head and neck contain one of the human papilloma viruses that produce proteins that combine with and inactivate p53 and pRB proteins, rendering mutations in these genes unnecessary.
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PMID:Genetics of tumors of the head and neck. 839 Dec 74

Using a series of tumorigenic and non-tumorigenic somatic cell hybrids that resulted from the fusion of the human osteosarcoma cell line OHS50-P16T (P16T) with the HeLa cell line D98OR, we investigated the role that genetic mutations, including alterations of oncogenes, tumor suppressor genes, and chromosomes, play in P16T tumorigenicity. Analysis of a previously identified oncogene mutation, c-myc amplification, in the P16T cell line demonstrated that both the tumorigenic and non-tumorigenic hybrids contained the amplified c-myc gene. Analysis of previously identified P16T tumor suppressor gene alterations, p53 mutation, and loss of RB1 expression demonstrated that the mutated p53 gene was selectively maintained in both the non-tumorigenic and tumorigenic hybrids, whereas loss of RB1 expression was not maintained in either the non-tumorigenic or tumorigenic hybrids. Chromosomes 11, 13, 17, and 22 were analyzed for loss of heterozygosity (LOH) to characterize the status of these previously described chromosomal alterations in the tumorigenic and non-tumorigenic hybrids. Loss of HeLa D98OR chromosome 22, with maintenance of P16T chromosome 22, was observed in the tumorigenic hybrids, a result confirmed by LOH analysis, which demonstrated the specific loss of HeLa chromosome 22 genetic material in the tumorigenic segregants. Together, these results demonstrated that amplified c-myc, mutant p53, and RB1 genes seem to be important in osteosarcoma tumorigenicity and that an additional altered gene or genes on chromosome 22 may play a key role in osteosarcoma tumorigenicity.
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PMID:Analysis of oncogene, tumor suppressor gene, and chromosomal alterations in HeLa x osteosarcoma somatic cell hybrids. 1033 42

Inheritance of a mutant allele of the breast cancer susceptibility gene BRCA1 confers increased risk of developing breast and ovarian cancers. Likewise, inheritance of a mutant allele of the retinoblastoma susceptibility gene (RB1) results in the development of retinoblastoma and/or osteosarcoma, and both alleles are often mutated or inactivated in sporadic forms of these and other cancers. We now demonstrate that the product of the RB1 gene, Rb, regulates the expression of the murine Brca1 and human BRCA1 genes through its ability to modulate E2F transcriptional activity. The Brca1 gene is identified as an in vivo target of E2F1 in a transgenic mouse model. The Brca1 promoter contains E2F DNA-binding sites that mediate transcriptional activation by E2F1 and repression by Rb. Moreover, ectopic expression of cyclin D1 and Cdk4 can stimulate the Brca1 promoter in an E2F-dependent manner, and this is inhibited by coexpression of the p16(INK4a) cyclin-dependent kinase inhibitor. The human BRCA1 promoter also contains a conserved E2F site and is similarly regulated by E2F1 and Rb. This functional link between the BRCA1 and Rb tumor suppressors may provide insight into the mechanism by which BRCA1 inactivation contributes to cancer development.
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PMID:Regulation of BRCA1 expression by the Rb-E2F pathway. 1066 Jun 29

In order to assess the role of genetic predisposition in the induction of radiation-induced tumors, we performed statistical analysis on data from the literature and from our own Institute with regard to the age at onset and the latency period of osteosarcoma as the second primary tumor for retinoblastoma with or without subsequent radiotherapy. In retinoblastoma survivors who subsequently developed osteosarcoma, the age at onset of retinoblastoma was young (average of 12 months) in both unilateral and bilateral forms. This suggests that all or almost all of the patients were genetically predisposed by a mutation of one allele of the RB1 gene. For retinoblastoma patients, osteosarcomas occurred 1.2 years earlier inside than outside the radiation field. The latency period between radiotherapy and osteosarcoma onset was 1.3 years shorter inside than outside the radiation field. Interestingly, a bimodal distribution of latency periods was observed for osteosarcomas arising inside, but not outside the radiation field: 40% occurred after a short latency, while the latency of the remaining 60% was comparable to that of osteosarcoma occurring outside the radiation field. This suggests that different mechanisms may be involved in radiocarcinogenesis. A radiation-induced mutation of the second RB1 allele may be the cause of osteosarcomas occurring after a short delay, while other genes may be affected in those occurring after a longer delay.
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PMID:Osteosarcoma following retinoblastoma: age at onset and latency period. 1144 17

Multidrug resistance to anti-cancer agents (MDR) is a major barrier to successful cancer treatment. Current knowledge about genes that contribute to MDR is limited, however, and its mechanisms remain unclear. To identify genes involved in MDR, we performed differential display analysis and isolated a novel human gene, RB1CC1 (RBI-inducible Coiled-Coil 1). The 6.6-kb RB1CC1 cDNA encodes a putative 1594-amino-acid protein that contains a nuclear localization signal, a leucine zipper motif and a coiled-coil structure. Western blot analysis and immunocytochemical staining with anti-RB1CC1 antibody showed that endogenously expressed RB1CC1 protein localized to the nucleus. In MDR variants of human osteosarcoma cells, RB1CC1 expression increased in response to doxorubicin-induced cytotoxic stress and remained elevated for the duration of drug treatment. RB1CC1 expression levels correlated closely with those of RB1 (retinoblastoma 1) in cancer cell lines as well as in various normal human tissues. Moreover, introduction of wild-type RB1CC1 significantly induced RB1 expression in human leukemic cells. These data suggest that RB1CC1 may be a key regulator of RB1 gene expression.
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PMID:Identification of RB1CC1, a novel human gene that can induce RB1 in various human cells. 1185 Aug 49

RB1-inducible coiled-coil 1 (RB1CC1) is a nuclear DNA-binding protein that can induce RB1 (retinoblastoma 1) expression. RB1CC1 is abundantly expressed in human musculoskeletal and cultured osteosarcoma cells. The present study analyzed the expression of RB1CC1 and RB1 in osteosarcoma cells and in musculoskeletal cells of human embryos to evaluate the contribution of both genes to the maturational process of musculoskeletal cells. The amount of RB1CC1 message was closely related to RB1 expression in various osteosarcoma cell lines. RB1CC1 expression was difficult to detect in immature proliferating chondroblasts or myogenic cells in human embryos, but became obvious and prominent concomitantly with the maturation of osteocytes, chondrocytes, and skeletal muscle cells. RB1CC1 expression in these musculoskeletal cells increased with RB1 expression, which is linked to the terminal differentiation of many tissues and cells. In addition, the introduction of wild-type RB1CC1 decreased the formation of macroscopic colonies in the cell growth assay. Accordingly, both RB1CC1 and RB1 genes preferentially co-expressed and contributed to the maturation of human embryonic musculoskeletal cells, and may regulate the proliferative activity and maturation of tumor cells derived from these tissues.
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PMID:Preferential expression of RB1-inducible coiled-coil 1 in terminal differentiated musculoskeletal cells. 1216 59

Alterations of the retinoblastoma (RB1) tumor suppressor gene are not only associated with retinoblastoma but also with several other malignancies including osteosarcoma. Besides direct sequence alterations, hypermethylation of a CpG island in the promoter region can cause inactivation of the RB1 gene as it has been shown in retinoblastomas. We examined the methylation status of the RB1 gene in 25 osteosarcoma specimens by using the methylation-sensitive restriction enzymes SacII and SmaI. The restriction fragments were hybridized with clone p123, which is a 1.8-kb genomic subclone that spans the RB1 CpG island including the promoter region and exon 1. Whereas we reconfirmed hypermethylation of the RB1 gene in a sporadic retinoblastoma, no hypermethylation could be detected in the 25 osteosarcoma specimens, suggesting that hypermethylation of the RB1 promoter is not of major importance during osteosarcoma genesis.
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PMID:Methylation status of the retinoblastoma gene (RB1) in osteosarcoma: no evidence for hypermethylation. 1466 Mar 7

One of the goals of biomedical scientists in this exciting era of molecular biology is the discovery of novel genes and their relationship to the molecular basis of disease. Part of this information connecting the geno-type to the phenotype is already known and available through hubs such as LocusLink. Although Locus-Link is a valuable resource that organizes curated information around genes and provides links to other online resources, it has not been developed for users to visualize graphically the association between genes and diseases, nor to navigate easily from genotype to phenotype (and back) within the same application. The application we developed, g2p, aims at visualizing graphically and navigating genetic disease information, especially the link between genotype and phenotype. The information displayed comes from a LocusLink query on human genes associated with a known disease (1330 genotypes, 1835 phenotypes, and 2050 associations). This application is based, in part, on the graph visualization package GraphViz. Starting from a disease query, g2p displays the phe-notype view (Figure 1). Alternatively, from a gene query, it creates a genotype view (Figure 2). In the example here, a search on the disease Bladder cancer leads to several genes, including RB1 (Figure 1). The double frame around RB1 indicates that it is linked to more than one disease and thus is "navigable". Following this link leads to the several diseases associated with RB1, including - besides Bladder cancer - Retinoblstoma and Osteosarcoma (Figure 2). The latter disease also has a double frame, indicating that several genes are associated with it.
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PMID:Graphical visualization and navigation of genetic disease information. 1472 97

Multidrug resistance (MDR) to anticancer agents is a major barrier to the successful treatment of human osteosarcomas. Current understanding of the genes that contribute to the features of MDR is limited, and the mechanisms remain unclear. Here we applied differential display reverse transcription-polymerase chain reaction (DDRT-PCR) to parental and MDR-variants of U-2 OS human osteosarcoma cells, to clarify the genes involved in the MDR cells, and identified five candidate genes. These are BCRP (breast cancer resistance protein) encoding a transmembrane efflux pump; RB1CC1 (RB1-inducible coiled-coil 1), a tumor suppressor regulating RB1 (retinoblastoma 1) expression; a novel transcriptional variant of dUTPase; SSR2 (beta-signal sequence receptor), which is associated with protein translocation across ER membrane; and HSP105 encoding high molecular mass heat shock proteins. Molecular and biological characterization of these genes will yield further insight into the features between MDR and tumor progression in human osteosarcomas.
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PMID:Differentially expressed genes in multidrug resistant variants of U-2 OS human osteosarcoma cells. 1513 64

Osteogenic sarcoma (osteosarcoma) is the most common primary tumor of bone. It accounts for approximately 19% of all malignant tumors of the bone. Of all the molecular targets altered during the genesis of osteosarcoma, the retinoblastoma gene (RB1) shows the highest frequency of inactivation. Published data from human osteosarcoma tumors and in vivo and in vitro model systems support a role for the retinoblastoma gene family in bone development and tumorigenesis. Although a variety of bone tumors, depending on the cell of origin, including osteoclasts or osteoclast-like cells, chondroblasts, and fibroblasts, are described, for the purpose of this review we will focus primarily on the tumors arising from the osteoblast lineage.
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PMID:The retinoblastoma protein in osteoblast differentiation and osteosarcoma. 1710 Jun 5


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