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)

Methotrexate reduces intracellular pools of 5-methyltetrahydrofolate and could result in reduced conversion of homocysteine to methionine by methionine synthetase. This study was designed to investigate the effects of moderate dose to very high dose methotrexate on methionine and total homocysteine as reflections of methotrexate induced intracellular events. Methionine and total homocysteine were measured prior to, during, and following twenty-six 24-h i.v. infusions of 33.6 g/m2 methotrexate (very high dose methotrexate) in 16 children with acute lymphocytic leukemia and seven 4-h i.v. infusions of 8 g/m2 methotrexate (high dose methotrexate) in 5 children with osteogenic sarcoma. Amino acids were measured by gas chromatography/mass spectrophotometry. Mean methionine levels decreased by 70.0 +/- 3.1% (SE) with very high dose methotrexate and 72.6 +/- 5.9% with high dose methotrexate at 24 and 4.5 h, respectively, after beginning methotrexate infusions. Mean total homocysteine levels increased by 61.7 +/- 3.1% with very high dose methotrexate and 55.6 +/- 17.5% with high dose methotrexate at 36 and 24 h, respectively, after beginning methotrexate infusions. No consistent or significant changes were noted in levels of total cysteine, leucine, isoleucine, or valine. Similar changes did not occur in patients receiving prednisone, vincristine, daunomycin, and intrathecal methotrexate as therapy for acute lymphocytic leukemia. These changes in homocysteine and methionine may reflect biological effects of methotrexate that may predict cytotoxicity of methotrexate.
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PMID:Changes in plasma methionine and total homocysteine levels in patients receiving methotrexate infusions. 279 Aug 1

We present a characterization of an activated oncogene which we found to be present in DNA of the OHA osteosarcoma cell line. We identify this tumor oncogene which transforms Swiss mouse 3T3-cells, with c-ras-Ki 2, one of two known members of the Kirsten ras family of human proto-oncogenes. Its structural outlines are given and we show that: 1) a single point mutation causing a substitution of valine for glycine in codon 12 was found by DNA sequencing; 2) the c-ras-Ki gene is amplified and overexpressed in the original OHA tumor cells and its transformants and 3) the gene product is an abnormal form of the p21 protein.
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PMID:A c-ras-Ki oncogene is activated, amplified and overexpressed in a human osteosarcoma cell line. 347 15

A human p53 mutant, p53Val-138 (amino acid 138, Alanine-->Valine), generated by in vitro mutagenesis was introduced into Saos-2 human osteosarcoma and Jurkat acute T-lymphoblastic leukemia cell lines, both lacking p53 protein expression. p53Val-138 caused growth arrest in Saos-2 cell line and apoptosis in Jurkat cell line at 32.5 degrees C while it allowed both cell lines to grow continuously at 37.5 degrees C. p53Val-138 activated expression of p53-responsive genes including MDM2, GADD45 and WAF1/CIP1/SD11 in Saos-2 cell line upon the temperature shift-down from 37.5 degrees C to 32.5 degrees C. Thus, p53Val-138 acted as a temperature-sensitive p53 mutant. Taking advantage of these human cell systems, we demonstrated that p53-mediated cell cycle arrest occurred in G1 and G2/M phases of Saos-2 cell line but not in Jurkat cell line. The induced level of WAF1/CIP1/SDI1 mRNA by p53 was extremely lower in Jurkat cell line than that of Saos-2 cell line. However, MDM2 mRNA accumulated to the similar levels in these two cell lines. These results suggest that a factor(s) other than p53 may be involved in differential expression of WAF1/CIP1/SDI1 and MDM2 mRNA.
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PMID:A human temperature-sensitive p53 mutant p53Val-138: modulation of the cell cycle, viability and expression of p53-responsive genes. 762 16

The hSEP1 gene is the human homolog of yeast SEP1. Yeast SEP1 is a multifunctional gene that regulates a variety of nuclear and cytoplasmic functions including homologous recombination, meiosis, telomere maintenance, RNA metabolism and microtubule assembly. The function of hSEP1 is not known. We show loss or reduced expression of hSEP1 messenger RNA (mRNA) in three of four primary osteogenic sarcoma (OGS)-derived cell lines and in eight of nine OGS biopsy specimen. In addition, we find a heterozygous missense mutation (Valine(1484)>Alanine) at a conserved amino acid in the primary OGS-derived cell line U2OS. Importantly, we identified a homozygous missense mutation involving a CG-dinucleotide leading to a change in a conserved amino acid, aspartic acid(1137) >asparagine, in the primary OGS-derived cell line, TE85. hSEP1 mRNA expression was nearly undetectable in TE85 and low in U2OS cell lines. None of these mutations were identified in 20 normal samples consisting of bone, cartilage and fibroblast. The hSEP1 gene is located in chromosome 3 at 3q25-26.1 between markers D3S1309 and D3S1569. An adjacent locus defined by the polymorphic markers D3S1212 and D3S1245 has previously been reported to undergo loss of heterozygosity (LOH) at a >70% frequency in OGS and claimed to harbor an important tumor suppressor gene in osteosarcoma. The homozygous mutation in the hSEP1 mRNA in TE85 cell line suggest that this gene itself is subject to LOH. Taken together, these results suggest that hSEP1 acts as a tumor suppressor gene in OGS.
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PMID:The human homolog of yeast SEP1 is a novel candidate tumor suppressor gene in osteogenic sarcoma. 1242

High-dose methotrexate is a standard component of therapy for high-grade osteosarcoma. Its effectiveness may be limited by intrinsic and acquired resistance. Decreased reduced folate carrier (RFC) expression has been shown in approximately half of osteosarcomas at diagnosis. Mutations and polymorphisms in the RFC gene have been reported in various cell lines. The purpose of this study was to investigate sequence alterations in the RFC gene in osteosarcoma tumor samples. The entire coding region of the RFC gene in samples from 162 osteosarcoma patients was screened by DNA single-stranded conformational polymorphism, followed by direct sequencing of any region with altered mobility. A previously identified polymorphism at cDNA position number 174 of RFC exon 2 was observed. Sixty-one samples (37.6%) were heterozygous with both A/G at this position (His(27)/Arg(27)), 52 samples (32.2%) were homozygous with G (Arg(27)), and 49 samples (30.2%) were homozygous with A (His(27)). Fifteen (9.2%) samples were identified with other RFC sequence variants in exon 2, none of which have been reported. The sequence variants in exon 2 included a G to A substitution at cDNA position 231, a G to A substitution at cDNA position 155, a C to T substitution at cDNA position 114, and a T to C substitution at cDNA position 104, resulting in a serine to asparagine substitution at amino acid 46, a glutamate to lysine substitution at amino acid 21, an alanine to valine substitution at amino acid 7, and a serine to proline substitution at amino acid 4, respectively. A deletion of A at cDNA position 126 resulting in a frameshift was also observed. Some of these variants were observed in multiple samples. Eight samples had altered single-stranded conformational polymorphism patterns in exon 3 that were associated with nucleotide changes that altered the amino acid sequence. All of these RFC sequence variants appeared to be heterozygous. Heterozygous C/T and homozygous C also were observed at RFC cDNA position 790 in exon 3, which does not alter the amino acid coding sequence. This study shows that RFC sequence alterations are frequent in samples from osteosarcoma patients. Additional studies are under way to determine the clinical significance of these sequence alterations and their effect on methotrexate transport and resistance.
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PMID:Sequence alterations in the reduced folate carrier are observed in osteosarcoma tumor samples. 1257 57

Food-derived bioactive peptides are reported to express a variety of functions in vivo. We studied the in vitro effect of three bioactive tripeptides, isoleucine-proline-proline (IPP), valine-proline-proline (VPP) and leucine-lysine-proline (LKP), on osteoblast proliferation and gene expression. We used UMR-106 osteosarcoma cells, human marrow-derived mesenchymal stem cells (hMSC) and osteoblasts differentiated from hMSC. Treatment with 50 mum-IPP increased UMR-106 cell and hMSC proliferation. The gene expression of hMSC-differentiated osteoblasts was analysed by the microarray method. Microarray analysis revealed that IPP up-regulated 270 genes and down-regulated 100 genes. VPP and LKP, by contrast, had a very modest influence on osteoblast gene expression. Real-time PCR confirmed that IPP up-regulated PTHrP, BMP-5 and CREB-5 and down-regulated VDR and caspase-8. IPP possesses potential to increase osteoblast proliferation, differentiation and signalling. Agents that increase the number and function of osteoblasts could improve bone mass and structure, and decrease fracture risk.
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PMID:Effects of bioactive peptides isoleucine-proline-proline (IPP), valine-proline-proline (VPP) and leucine-lysine-proline (LKP) on gene expression of osteoblasts differentiated from human mesenchymal stem cells. 1746 96

A series of novel amino acid ester derivatives of 2,3-substituted isoindolinones was synthesized and evaluated for p53-mediated apoptotic activity. The rationale for augmentation of the target activity of 2,3-substituted isoindolinones was based on the introduction of new fragments in the structure of the inhibitor that would provide additional binding sites in the hydrophobic cavity of MDM2. To select for the anticipated modifications we employed molecular docking. Synthesized molecules were evaluated for their ability to induce apoptosis in two cancer cell lines and their derivatives with different status of p53 (colorectal HCT116 and osteosarcoma U2OS cells) by Annexin V staining. The target activity was estimated using high-content imaging system Operetta. Valine and phenylglycine ester derivatives were identified as potentially active MDM2-p53 inhibitors.
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PMID:Proapoptotic modification of substituted isoindolinones as MDM2-p53 inhibitors. 2908 30

H3F3A mutations and the expression of glycine 34 to tryptophan (G34W) mutants in giant cell tumors of bone (GCTBs) and other bone tumors were detected to compare H3F3A mutation types and the expression of G34W-mutant protein in order to provide a theoretical basis for using H3F3A mutations as a diagnostic and differential-diagnostic tool for GCTBs. A total of 366 bone tumor cases were investigated. The cases involved 215 men and 151 women, whose median age was 29 years (3-84). The cases included GCTB (n=180), recurrent GCTB (n=19), GCTB with lung metastasis (n=5), pediatric GCTB (n=15), primary malignant GCTB (n=5), chondroblastoma (CB, n=61), chondrosarcoma grade II (n=15), dedifferentiated chondrosarcoma (n=17), chondromyxoid fibroma (n=9), aneurysmal bone cyst (n=9), nonossifying fibroma (n=9), osteosarcoma (n=16), and undifferentiated sarcoma (n=6). Sanger DNA sequencing analysis was used to detect H3F3A mutations. Immunohistochemistry was used to assess the expression of the G34W-mutated protein in these bone tumors. DNA sequencing results revealed H3F3A mutations in 95.00% of GCTBs (171/180), including glycine 34 to tryptophan (G34W, 163/180, 90.56%), glycine 34 to leucine (G34L, 3/180, 1.67%), glycine 34 to valine (G34V, 3/180, 1.67%), and glycine 34 to arginine (G34R, 2/180, 1.11%). Recurrent GCTBs mostly had the H3F3A G34W mutation (18/19, 94.74%), and GCTBs with lung metastasis all had the H3F3A G34W mutation (5/5, 100%). Pediatric GCTBs had a mutation rate of 93.33% (14/15), including one case with G34L. Four cases of primary malignant GCTB showed the H3F3A G34W mutation (4/5, 80.00%), and the classical GCTB component and malignant component showed consistent mutation types. Immunohistochemistry showed that GCTBs harboring G34W also expressed the mutant protein in tumor cell nuclei. Furthermore, one case of GCTB and one case of recurrent GCTB showed positive G34W immunostaining results despite being negative for the genetic mutation. Other bone tumors all showed wild-type expression in both DNA sequencing and immunohistochemistry. Our large-sample DNA sequencing analysis detected four different forms of mutations in GCTBs, including three rare mutation forms. The most common mutation of H3F3A was G34W, which was in accordance with the expression of G34W in GCTBs detected by immunohistochemistry. Although DNA sequencing analysis detected rare mutation types of H3F3A, false-negative results were also present due to the small number of cells in the samples. Detection of the most common (G34W) mutant protein by immunohistochemistry was more convenient. Given the high prevalence of these driver mutations, the detection of H3F3A mutant proteins can assist in the diagnosis of GCTB and its differential diagnosis from other bone tumors.
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PMID:H3F3A G34 mutation DNA sequencing and G34W immunohistochemistry analysis in 366 cases of giant cell tumors of bone and other bone tumors. 3302 29