Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
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.
 ...
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.
 ...
PMID:The human met oncogene is a member of the tyrosine kinase family. 333 11

The met protooncogene was activated by a rearrangement involving the fusion of tpr (1q25) and met (7q21-31) gene sequence in a human osteosarcoma cell line (HOS) incubated in vitro with N-methyl-N-nitro-N-nitrosoguanidine (MNNG). We examined the expression of tpr-met mRNA by means of the reverse transcription-nested polymerase chain reaction (RT-nested PCR) in human two gastric cell lines (MKN-1 and MKN-45), T-cell acute lymphocytic leukemia cell line (MOLT-4), and in gastric tissue samples including normal mucosa, intestinal metaplasia and carcinoma from three surgical specimens. A DNA fragment of 88-bp was amplified in MKN-1 and MOLT-4, 96-bp in MKN-45 and of 58-bp in all nine tissue samples including gastric carcinomas. The amplified DNA sequences were not homologous with the rearranged tpr-met gene. Our study indicated that rearranged tpr-met mRNA is not expressed either in human gastric carcinoma cell lines or in gastric mucosa and carcinoma.
 ...
PMID:Lack of rearranged Tpr-met mRNA expression in human gastric cancer cell lines and gastric mucosa and carcinoma. 891 2