UMLS:C0029463 - FACTA Search

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

This paper studies the cytotoxic effect induced by the topoisomerase I inhibitor camptothecin in human osteosarcoma Saos-2 cells, which lack p53 and contain a non-functional form of the product of the retinoblastoma gene, pRb. Cytotoxicity induced by camptothecin was dose- and time-dependent; the treatment with 100 nM camptothecin reduced cell viability by 50% at 32 h and by 75% at 72 h of exposure. The cytotoxic effect was caused by apoptosis, as ascertained by morphological evidence, acridine orange-ethidium bromide staining and flow cytometric analysis. Apoptosis was accompanied by both the activation of caspase-3 and the fragmentation of poly(ADP-ribose) polymerase. Treatment with camptothecin caused a threefold increase in the activity of c-Jun N-terminal kinase (JNK) and an eightfold increase in the level of phosphorylated c-Jun. The introduction of the RB gene into Saos-2 cells reduced the rate of cell growth. Moreover, stable clones of transfected cells were resistant to camptothecin. Exposure to 100 nM camptothecin for 72 h reduced the viability of transfected cells by only 10%; moreover, very modest effects were observed on the activity of JNK as well as on the level of phosphorylated c-Jun. The results reported in this paper support the conclusion that the expression of wild-type pRb in Saos-2 cells exerts an anti-apoptotic influence through the control of JNK activity.
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PMID:pRb suppresses camptothecin-induced apoptosis in human osteosarcoma Saos-2 cells by inhibiting c-Jun N-terminal kinase. 1141 38

We have investigated the effect of changes in the gravity vector on osteoblast behaviour, using the clinostat set at 8 rpm. Two sources of osteoblasts were used: secondary cultures of fetal rat bone cells, and the rat osteosarcoma line 17/2.8 (ROS). Cell number was determined by incubation with 3-(4,dimethyl-2yl)-2,3 diphenyl) tetrazolium bromide (MTT) and measurement of optical density at 570 nm (OD). Alkaline phosphatase activity was detected by standard cytochemical methods. Dividing cells were localised by labelling dividing nuclei with Bromodeoxyuridine (BrdU), detected by immunofluorescence. Cell culture was initiated at densities between 1-4x10(4) cells ml-1. Growth rates in all cultures during the first 48 hours exposure to clinostat rotation were less than in stationary controls. After 3 days, ROS cell numbers were 35% lower, and calvarial cells 39% lower than their respective controls. Alkaline phosphatase activity in calvarial control cultures was uniformly present in characteristically polygonal cells, but after culture in the clinostat the enzyme was present sporadically, and the cells were cuboid. There was also no BrdU uptake in nuclei, but it was present in cell cytoplasms. We conclude that the clinostat decreases cell numbers and cell division. Both cell shape and the distribution of alkaline phosphatase activity in calvarial cell cultures were also affected. This implies that changes in the gravity vector can affect osteoblasts directly, without interaction with other cell types.
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PMID:Effect of clinostat rotation on differentiation of embryonic bone in vitro. 1153 15

p53 tumor suppressor is activated by phosphorylation and acetylation on DNA damage. One of unknown p53 early transcripts was identified to be histone deacetylase-5 (HDAC5). We tested a hypothesis that HDAC5 is a p53 down-stream target gene that on induction by p53 inactivates p53 by removal of acetyl group in p53 molecule, thus functioning as an auto-regulatory negative feedback loop in analogue to p53-murine double minute 2 interaction. Six p53 binding consensus sites were identified in the promoter of HDAC5. p53 binds to one of the sites weakly. However, luciferase constructs driven by the HDAC5 promoter containing three to six potential binding sites were not activated by p53, nor was the expression of HDAC5 mRNA induced by p53-activating agents. Furthermore, HDAC5 does not bind to p53 nor reduces etoposide-induced p53 acetylation. Thus, HDAC5 is not a p53 target gene and may act in a p53-independent manner. We next studied the effect of HDAC5 on tumor cell growth and apoptosis. Transfection of HDAC5 inhibited growth of multiple tumor cell lines including U2OS osteogenic sarcoma cells, SY5Y neuroblastoma cells, and MCF breast carcinoma cells. The growth suppression seen in HDAC5-overexpressing cells appears to be attributable partly to a reduced growth rate as revealed by cell growth assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and mainly to spontaneous apoptosis as shown by DNA fragmentation ELISA and morphological appearance. Mechanistically, repression of three cell proliferation genes in mitogen-activated protein kinase pathway and induction of seven apoptosis-related genes were identified by microarray profiling in HDAC5-overexpressed cells. Among induced genes, four (TNFR1, TNFSF7, caspase-8, and DAPK1) were associated with the tumor necrosis factor ligand-receptor death pathway. Induction of TNFR1, TNFSF7, and caspase-8 were confirmed by Northern and Western analyses. Thus, activation of tumor necrosis factor death receptor pathway appears to be associated with HDAC5-induced spontaneous apoptosis.
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PMID:Histone deacetylase 5 is not a p53 target gene, but its overexpression inhibits tumor cell growth and induces apoptosis. 1201 72

Using a model with external ligation of the thigh, the effect of ischemia-reperfusion injury on tumor growth and the activity of lung metastasis was investigated in mice inoculated a spontaneous murine osteosarcoma cell line (POS-1) in vivo. POS-1 cell suspension was inoculated into the right hind footpad of 70 mice. Four weeks after inoculation, the ipsilateral thigh was ligated for 3 h in 15 mice and the contralateral thigh in 15 mice. Another ten mice were inoculated with POS-1 without ligating the thigh. The number of metastatic foci on the lung surface 6 weeks after inoculation was 2.29+/-0.98 (mean+/-SE) foci/lungs in mice with ipsilateral ligation and 6.25+/-2.41 in mice with contralateral ligation, which were significantly lower than control (13.40+/-1.42 in mice no ligation) (P<0.01). The number of metastatic foci on the lung surface in mice with intraperitoneal injection of superoxide dismutase (SOD) and catalase was 3.25+/-0.65 (mean+/-SE) foci/lungs in mice with ligation which was significantly greater than that in mice without SOD and catalase injection 1.29+/-0.97 (P=0.04). Cell viability was 9.12+/-4.07% with 100 microM H(2)O(2) in 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. It revealed that at concentrations of 100 microM H(2)O(2) or higher was cytotoxic to POS-1. In cell invasion assay, the number of invading cells with 10 microM H(2)O(2) was 2.80+/-0.53 cells/field, which was significantly lower than control (5.93+/-0.18) (mean+/-SE), indicating that low-dose H(2)O(2) suppressed invasion of POS-1. These results suggested that reperfusion injury had selective cytotoxicity to POS-1 through producing reactive oxygen species. Activated oxygen was considered to inhibit the regional growth and the ability of lung metastasis of POS-1 cells.
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PMID:Inhibition of lung metastasis of osteosarcoma cell line POS-1 transplanted into mice by thigh ligation. 1240 67

Chitosan-DNA nanoparticles were synthesized from the complexation of the cationic polymer with a ss-gal DNA plasmid, in order to study the efficacy of chitosan to develop a non-viral gene delivery system that can be optimized for efficient gene therapy. The optimal binding conditions were determined with the fluorescamine and PicoGreen assays. DNA distribution within the nanoparticle was visualized by electron transmission microscopy, while the size and morphology were assessed by atomic force microscopy. The transfection potential was evaluated for the first time on human mesenchymal stem cells (MSCs), on human osteosarcoma cells (MG63) and on human embryonic kidney cells (HEK293). The LipofectAMINE(TM) 2000 (LF) reagent was used in comparison. The effect of chitosan-DNA nanoparticles on cell viability was illustrated with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. The nanoparticles formed are of a diameter inferior to 100nm with a homogenous distribution of DNA. The transfection of HEK293 cells is superior to that seen with MG63 cells and MSCs, however not surpassing that seen with LF. Minimal cytotoxicity is seen with the polyplexes compared to greater than 50% toxicity with LF. These results suggest that chitosan-DNA nanoparticles have favorable characteristics for non-viral gene delivery, are cell type dependent and not cytotoxic.
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PMID:Mesenchymal stem cells, MG63 and HEK293 transfection using chitosan-DNA nanoparticles. 1252 66

Aminopeptidase N (APN/CD13), a Zn2+-dependent ectopeptidase, is localized on the cell surface and functions as a transmembrane protein. Increased expression and activity of APN have been postulated to correlate with the aggressive behavior of several tumor types. In this study, the osteosarcoma cell line MNNG/HOS was stably transfected with an expression vector capable of expressing the antisense transcript of APN. Four stably transfected clones, the control clones and parental cells were characterized. Stable integration of the antisense vector was confirmed by PCR analysis of genomic DNA. Competitive RT-PCR revealed that mRNA expression of antisense-transfectants was decreased to approximately 37% of the control cell line. The activity assay showed that the enzymatic activity of APN was inhibited to approximately 51% of the control cell line. Antisense-transfection had no influence on the cellular proliferation measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, on the motility in Transwell chambers, and on the adhesive potential to collagen I. However, an in vitro invasion assay revealed a significant decrease in the number of cells that migrated through a reconstituted membrane (51% of the control cell line). The adhesive potential to Matrigel was also affected (73% of the control cell line). Furthermore, under in vivo conditions, a reduced potency to metastasize to the lung was shown in an experimental metastasis assay in nude mice. These findings demonstrate that APN plays an active role in the cellular attachment and proteolytic degradation of the extracellular matrix in the metastatic process of osteosarcomas.
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PMID:Inhibitory effect of antisense aminopeptidase N (APN/CD13) cDNA transfection on the invasive potential of osteosarcoma cells. 1466 89

Folic acid derivatives such as folinic acid and methotrexate (MTX) have been successfully hybridized with layered double hydroxide (LDH) by ion-exchange reaction. The X-ray diffraction patterns and spectroscopic analyses indicate that these molecules intercalated into the hydroxide interlayer space are stabilized in the tilted longitudinal monolayer mode by electrostatic interaction. No significant changes in their structural and functional properties are found in the hybrids. The cellular uptake test of MTX-LDH hybrid is carried out in the fibroblast (human tendon) and SaOS-2 cell line (Osteosarcoma, human) by in vitro MTT (3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide) assay. The initial proliferation of SaOS-2 cell is more strongly suppressed by treatment with MTX-LDH hybrid than with MTX alone. This study clearly shows that LDH not only plays a role as a biocompatible-delivery matrix for drugs but also facilitates a significant increase in the delivery efficiency.
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PMID:Layered double hydroxide as an efficient drug reservoir for folate derivatives. 1496 39

The pattern of inhibition of cell proliferation and cytotoxicity in vitro by 1,4-bis(1-naphthyl)-2,3-dinitro-1,3-butadiene (Naph-DNB) was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and the trypan blue (TB) dye exclusion assays in nine murine and human cell lines of different histologic origin. In our culture conditions Naph-DNB showed a good inhibiting activity against all cell lines tested, with IC(50)s varying within a narrow micromolar range of concentrations (2.0 +/- 0.2-14.3 +/- 2.3 microM). In particular, murine P388 (leukemia), human Jurkat (leukemia), A2780, PA-1 (ovarian carcinoma) and Saos-2 (osteosarcoma) cells showed the highest sensitivity to the inhibiting potential of Naph-DNB, while human A549 (non small cell lung cancer, NSCLC), MDA-MB-231 (breast cancer), HGC-27 (gastric cancer) and HCT-8 (colon carcinoma) were the least sensitive cell lines. Moreover, the analysis of cytotoxicity of Naph-DNB evaluated by the TB test showed that this compound was able to kill cells with IC(50)s ranging from 1.7 to 39.2 microM. The study of the induction of apoptosis was carried out by 4'-6-diamidine-2'-phenylindole (DAPI) staining of segmented nuclei, western blot of p53 protein and TdT-mediated dUTP-biotin nick end labeling (TUNEL) method, while the interaction with DNA was evaluated through the analysis of interstrand cross-link (ISCL) formation. Our data show that in all cell lines tested Naph-DNB was able to form ISCLs, to upregulate p53 oncosuppressor-protein and to induce apoptosis. Moreover, TUNEL analysis also suggested that Naph-DNB, similarly to other anticancer drugs, was able to block cells in the G (0)/ G (1) phase of the cell cycle. In conclusion our data suggest that Naph-DNB may be an effective novel lead molecule for the design of new anticancer compounds.
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PMID:Preliminary evaluation in vitro of the inhibition of cell proliferation, cytotoxicity and induction of apoptosis by 1,4-bis(1-naphthyl)-2,3-dinitro-1,3-butadiene. 1529 6

Arsenite is a toxicant and environmental pollutant associated with multisite neoplasias and other health effects. The wide range of doses used and the claims that some high doses are "not toxic" in some assays have confounded studies on its mechanism of action. The purpose of this study is to determine whether the treatment time and particularly the duration between treatment and assay are important factors in assessing arsenite toxicity. We compared three commonly used assays: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR), and clonal survival, using human osteogenic sarcoma (HOS) cell line U-2OS. Results from the assays were well correlated only when the factor of time was taken into account. In both the MTT and NR assays, exposure to arsenite for 24 h induced much less toxicity than exposure for 48 or 72 h, which gave similar results. In contrast, results in clonal survival assays showed only a small difference between 24-h exposure and longer exposure times. Arsenite demonstrated delayed cytotoxicity, killing the cells even after its removal from the medium in NR assay. Apoptosis was assessed by TUNEL staining and caspase-3 activation. After treatment for 24 h with 0.1 and 1 microM arsenite, no apoptosis was seen. However, after an additional 24 h in arsenite-free medium, a small amount of apoptosis could be detected, and much more apoptosis was seen after 48 h. In contrast, 10 microM arsenite triggered rapid necrosis and failed to activate caspase 3 or cause TUNEL staining. We also confirmed previous reports that exposure to low concentrations of arsenite caused transient stimulation of cell growth. Our finding of delayed toxicity by arsenite suggests that to avoid underestimation of toxicity, the duration between treatment and assay should be taken into account in choosing appropriate doses for arsenite as well as for other toxicants that may show similar delayed toxicity. The NR and MTT assays should be performed only after an interval of at least 48 h after a 24-h exposure to arsenite.
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PMID:Dead or dying: the importance of time in cytotoxicity assays using arsenite as an example. 1558 80

Cyclooxygenase-2 (COX-2) inhibitors exert antitumor activity via COX-2-dependent and independent pathways. We wished to evaluate the antitumor activity of meloxicam, a preferential COX-2 inhibitor, in osteosarcoma, the most common primary malignant bone tumor, and determine whether its antitumor effect is COX-2-dependent. COX-2 expression in the osteosarcoma cell lines MG-63, HOS and U2-OS was determined by real-time RT-PCR and western blotting. Subsequently, the inhibitory effects of meloxicam on osteosarcoma cell growth and invasiveness were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and matrigel invasion assays, respectively. Apoptotic activity was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining and semi-quantification of Bax and Bcl-2 expression by real time RT-PCR and western blotting. Prostaglandin-E(2) (PGE(2)) production in the presence and absence of meloxicam was analyzed by enzyme immunoassay, and to determine whether the effects of meloxicam are COX-2-dependent or independent, PGE(2) was added to see if it reversed the effects of meloxicam. In addition, the effects of meloxicam on tumor growth and metastasis were evaluated in an in vivo mouse model using grafted LM-8 mouse osteosarcoma cells, together with immunohistochemical analysis for vascular endothelial growth factor in lung metastatic lesion. Meloxicam inhibited PGE(2) production, proliferation and invasiveness especially in MG-63 cells, which express relatively high levels of COX-2. Only high concentrations of meloxicam caused apoptosis and upregulated Bax mRNA and protein in MG-63 cell culture. In contrast, meloxicam did not induce apoptosis in HOS and U2-OS cells, expressing relatively low levels of COX-2. Exogenous PGE(2) reduced the effects of meloxicam on cell viability and invasiveness, but not its effect on Bax mRNA. In vivo, high doses of meloxicam suppressed LM-8 tumor growth and lung metastasis. Meloxicam, may have both COX-2-dependent and independent inhibitory actions on osteosarcoma. Its effects are more prominent in osteosarcoma cells that have relatively high levels of COX-2.
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PMID:Meloxicam inhibits osteosarcoma growth, invasiveness and metastasis by COX-2-dependent and independent routes. 1621 34

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