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)

A murine erythroleukemic cell line (1-2-3) which expresses only the temperature-sensitive mutant p53 gene (Ala-to-Val substitution at codon 135) was established. These cells showed typical characteristics of apoptosis, when they were cultured at 32 degrees C. In this process, p53 recovered the wild-type p53 function and the expression of the p21 (waf1/cip1/sdi1), cyclin G1 and gadd45 genes was increased. However, no significant changes were detected in the expression of the mdm2, bcl-2, bax, fas and fasl genes, suggesting the existence of other genes associated with apoptosis. Genes up-regulated by p53 were screened by the mRNA differential display method. One of the up-regulated genes was identified as the elongation factor 1 alpha (EF-1 alpha) gene. EF-1 alpha is also a microtubule-severing protein. Upon the temperature-shift, the cells developed the morphology and the localization of alpha-tubulin similar to those of the cells treated with vincristine, a drug that affects microtubules. The microtubule-severing associated with up-regulation of EF-1 alpha by p53 may be a cause of the cell death. On the other hand, the function of cyclin G1 is not so clear despite the fact that 1-2-3 cells showed a significant increase of the cyclin G1 gene during the early stage of apoptosis. The yeast two-hybrid system was used to identify cyclin G1-associated proteins. One is a cytochrome c (Cyt c) oxidase subunit II (COXII). Cyclin G1 and COXII were co-immunoprecipitated from an extract of human osteosarcoma cell line that expressed high levels of cyclin G1. COX activity was also increased by temperature-shift in this cell line. The pattern of changes in COX activity was closely reflected by the expression of the cyclin G1 gene. Cyclin G1 and COXII associate physically with each other in vivo and that activation of COXII by binding to cyclin G1 upregulated by p53 may be associated with apoptosis. These two new pathways, p53-EF-1 alpha-microtubule-severing (-distortion of cytoskeleton) and p53-cyclin G1-COXII (-CytC, ATP-caspase-3 activation), may cooperate to induce apoptosis in this cell line.
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PMID:The mechanisms of death of an erythroleukemic cell line by p53: involvement of the microtubule and mitochondria. 1019 36

Spontaneous apoptosis in human osteosarcoma cells was observed to be associated with a marked increase in the intracellular abundance of p53. Immunoprecipitation and immunoblot analysis revealed that, together with a variety of other nuclear proteins, p53 undergoes extensive poly(ADP-ribosyl)ation early during the apoptotic program in these cells. Subsequent degradation of poly(ADP-ribose) (PAR), attached to p53 presumably by PAR glycohydrolase, the only reported enzyme to degrade PAR, was apparent concomitant with the onset of proteolytic processing and activation of caspase-3, caspase-3-mediated cleavage of poly(ADP-ribose) polymerase (PARP), and internucleosomal DNA fragmentation during the later stages of cell death. The decrease in PAR covalently bound to p53 also coincided with the marked induction of expression of the p53-responsive genes bax and Fas. These results suggest that poly(ADP-ribosyl)ation may play a role in the regulation of p53 function and implies a regulatory role for PARP and/or PAR early in apoptosis.
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PMID:Poly(ADP-ribosyl)ation of p53 during apoptosis in human osteosarcoma cells. 1023 7

Progression through the cell cycle and redirection of cells towards programmed cell death (apoptosis) are tightly inter-related processes. However the requirement for tissue and cell type specificity suggests that a wide variety of mechanisms are used to achieve the same purpose. To examine this issue, we investigated cell cycle (c-myc, p53, p21/WAF) and apoptosis related (bcl-2, bcl-X(L), bax-alpha) gene expression in two cell lines of very different origin under proliferating and apoptosis-inducing conditions. Transformed human osteosarcoma cells (MG63) and non-transformed human kidney embryonal fibroblasts (293-0) were kept in culture in medium containing 10% FCS and growth arrest was induced by the addition of 50 ng/ml colcemid. Colcemid treatment caused growth arrest and elevated expression of cyclin B1 protein in both cell lines. Apoptosis was significantly elevated in both cell lines after colcemid exposure for at least one cell cycle. However the pattern of expression of cell cycle and apoptosis related genes, determined by RT-PCR, was quite different between the two cell lines during exponential growth and cell cycle arrest. Colcemid treatment did not markedly influence c-myc, p53 and p21/WAF expression in MG63 cells but did suppress c-myc and increase p21/WAF in 293-0 cells. Furthermore colcemid treated MG63 cells exhibited elevated bcl-2 and bax-alpha expression while similar treatment of 293-0 cells resulted in decreased bcl-X(L) and slightly increased bax-alpha expression. While growth arrest and apoptosis were induced in both MG63 and 293 cells following colcemid treatment, the differences in gene expression suggest that the mechanism by which these cells determine cell fate is quite different and may determine the sensitivity of different cell populations to anti-neoplastic drug therapy. The distinct patterns of gene expression should be carefully defined before mechanisms of apoptotic cell death are studied.
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PMID:Expression of apoptosis and cell cycle related genes in proliferating and colcemid arrested cells of divergent lineage. 1072 74

We recently obtained 3 cloned cell lines demonstrating the p53 mutation from a lung metastatic nodule of a rat transplantable osteosarcoma. In this study, we applied wild-type p53 gene transfer to the rat osteosarcoma cells by lipofection to investigate the effects on cell growth, expression of genes such as waf1/p21, bcl-2, and bax, and nucleosomal DNA fragmentation due to apoptosis. Reconstitution of the p53 gene inhibits cellular growth, and this growth-suppressive effect is partly due to apoptosis involving bcl-2 gene suppression in this tumor type. This rat osteosarcoma model is similar in biologic behavior to human cases and thus is very suitable for further investigation of tumorigenesis and gene therapy for osteosarcoma.
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PMID:Possible involvement of bcl-2 suppression in wild-type p53 gene-dependent cell growth repression in rat osteosarcoma cells. 1093 45

Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to produce an anti-proliferative and pro-apoptotic effect on different types of cancer cell lines. Previously, we demonstrated that high dose of NS-398 (100 microM), a selective cyclooxygenase-2 inhibitor, induced a cell cycle slowing or arrest and, in contrast to low dose (10 microM), a marked decrease in apoptosis in human 1547 osteosarcoma cells. In this study, we investigated particularly the effect of 100 microM NS-398 on p53 and p21 expression, caspase activities and nuclear factor-kappaB (NF-kappaB). We found a correlation between p53, p21 mRNA expression and NF-kappaB activation and, we observed an induction of heat shock protein 70 expression with a large decrease in caspase-3 activity after 100 microM NS-398 treatment. Moreover, the inhibition of apoptosis was correlated with an increase in bcl-2/bax ratio. Our new findings confirm the novel anti-apoptotic property of NS-398 at 100 microM, as we previously found, which contrasts to the described NS-398 pro-apoptotic effect on other cancer cell lines.
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PMID:The anti-apoptotic property of NS-398 at high dose can be mediated in part through NF-kappaB activation, hsp70 induction and a decrease in caspase-3 activity in human osteosarcoma cells. 1201 7

This report describes an individual with a rare choroid plexus papilloma in adulthood (age 29) after earlier having an osteosarcoma (age 22). The results from this study, and others, suggest that it may be advisable to consider the possibility of a germline p53 mutation in adults presenting with choroid plexus tumours. In the current study automated DNA sequencing of genomic DNA detected a novel germline 7 base pair insertion in exon 5 of the p53 gene in this patient. The alteration in frame would produce amino acid substitutions beginning with alanine to glycine at position 161 and a stop codon at position 182 in the mutated protein. Surprisingly two assays of p53 function gave apparently wild-type results on peripheral blood lymphocytes from this individual. These results led us to carry out more detailed functional tests on the mutant protein. The mutant allele was expressed either at very low levels or not at all in phytohaemagglutinin stimulated lymphocytes. Further, the mutant protein was completely non-functional in terms of its ability to transactivate a series of p53-responsive genes (p21(WAF1), bax, PIG3), to transrepress a target gene and to inhibit colony growth in transfected Saos-2 cells. However, surprisingly, data from irradiated peripheral blood lymphocytes and transfected Saos-2 cells, suggested that this truncated, mutant protein retains significant ability to induce apoptosis.
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PMID:Investigations on a clinically and functionally unusual and novel germline p53 mutation. 1208 9

This study investigates cell growth and death (apoptosis and necrosis) in actively proliferating MG-63 osteosarcoma spheroids in response to two doses of ionizing radiation (5 and 30 Gy). Cell growth was examined by growth curves and by cell cycle analyses utilizing flow cytometry. Death was examined in both disaggregated and whole spheroids by the chromatin dye Hoechst and by Western blot analysis of the bcl-2 family of proteins known to be involved in the apoptotic process. The results indicate that after exposure to 5 Gy MG-63 spheroids die by apoptosis, while after exposure to 30 Gy they die by necrosis. The analysis of the bcl-2 family of proteins demonstrates that bcl-2, bax and bcl-XL are involved in triggering apoptosis in spheroids exposed to 5 Gy. The possibility of studying the mechanisms responsible for radiation-induced cell death in three-dimensional spheroids (which represent much more closely in vivo tumors) is extremely important if the foundations for more selective and controllable clinical radiotherapeutic protocols are to be laid.
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PMID:Induction of apoptosis or necrosis by ionizing radiation is dose-dependent in MG-63 osteosarcoma multicellular spheroids. 1289 34

Tumor suppressor gene p53 is one of the most specific genetic alterations occurring in osteosarcoma pathogenesis. It is thought to be an early and key step in the tumorigenesis of osteosarcoma. However, whether the p53 status is a marker predictive of response to therapy and a marker of prognostic value remains controversial. The choice of p53 status detection method certainly account for discrepancies. The authors used a simple functional assay (functional analysis of separated alleles in yeast) on the tumor sample of an 8-year-old girl presenting with an osteosarcoma of the tibia. While making it possible to exclude the presence of a germline mutation, FASAY indicated the presence of a somatic p53 mutation lacking transcriptional activity on p21 and bax target genes. FASAY also strongly suggested a loss of heterozygosity p53, which was confirmed by cytogenetic analysis. Sequencing of cDNA extracted from yeast colonies containing mutated p53 identified a 213 stop mutation in exon 6. Despite these p53 alterations, the child is still in complete remission after a follow-up of 48 months.
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PMID:Identification of a transcriptionally inactive p53 mutant by functional analysis of separated alleles in yeasts (FASAY) in a child osteosarcoma tumor: a case report. 1520 94

Gene delivery via transferrin receptors, which are highly expressed by cancer cells, can be used to enhance the effectiveness of gene therapy for cancer. In this study, we examined the efficacy of p53 gene therapy in human osteosarcoma (HOSM-1) cells derived from the oral cavity using a cationic liposome supplemented with transferrin. HOSM-1 cells were exposed to transferrin-liposome-p53 in vitro, and the growth inhibition rate, expression of p53 and bax, and induction of apoptosis were measured 48 hours later. Treatment of HOSM-1 cells with transferrin-liposome-p53 resulted in 60.7% growth inhibition. Wild-type p53 expression and an increase in bax expression were observed following transfection with transferrin-liposome-p53, and 20.5% of the treated HOSM-1 cells were apoptotic. In vivo, the HOSM-1 tumor transplanted into nude mice grew to 5 to 6 mm in diameter. Following growth of the tumor to this size, transferrin-liposome-p53 was locally applied to the peripheral tumor (day 0) and then applied once every 5 days for a total of six times. During the administration period, tumor growth did not occur, and the mean tumor volume on the last day of administration (day 25) was 10.0% of that in the saline control group. These results suggest that p53 gene therapy via cationic liposome modification with transferrin is an effective strategy for treatment of osteosarcoma.
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PMID:p53 gene therapy of human osteosarcoma using a transferrin-modified cationic liposome. 1582 36

The prognostic significance of bax, cytochrome c, and caspase-8 in patients with primary osteosarcoma is unknown. We examined the immunohistochemical expression of these genes in 35 surgically treated patients with primary osteosarcoma. Clinicopathological and survival data were correlated with the staining result. Eighteen tissue specimens from non-malignant osseous lesions were used as controls. Bax, cytochrome c, and caspase-8 positive staining was observed in 29 (82.9%), 16 (45.7%), and 0 (0%) patients, respectively, but did not stain any of the 18 benign osseous lesions used as controls. None of the genes studied predicted overall or disease-free survival. Patients, however, bearing bax(+)/cytochrome c(+) or bax(+)/cytochrome c(+ +) tumors had a decreased 4-year disease-free survival rate compared to the rest of the group (p = 0.0489 and p = 0.0208, respectively), identifying two groups of patients where more intensive adjuvant treatment could possibly be applied to prevent high postoperative recurrence rates.
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PMID:Prognostic value of bax, cytochrome C, and caspase-8 protein expression in primary osteosarcoma. 1815 79


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