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)

Since apoptosis is the primary mode of cell death induced by cisplatin, the role of apoptosis and apoptosis-related gene products in cisplatin resistance was investigated in four human cisplatin-resistant cell lines of different tumour type. A common feature of the resistant sublines was a reduced susceptibility to drug-induced apoptosis compared to parental sensitive lines. Loss of wild-type p53 function was not a general event associated with the development of drug resistance. An increased bcl-2 expression was found in resistant cells characterized by mutant p53 (A431/Pt and IGROV-1/Pt), whereas in osteosarcoma (U2-OS/Pt) and in ovarian carcinoma (A2780/CP) cells with wild-type p53, bcl-2 levels were markedly reduced. U2-OS/Pt cells had a 16-fold increase in the level of Bcl-xL protein. Stable transfection of U2-OS cells with bcl-xL cDNA conferred a low level of drug resistance to cisplatin, suggesting that overexpression of this gene contributes to the cisplatin-resistant phenotype of this osteosarcoma cell system. In conclusion, these observations suggest a variable contribution of apoptosis-related genes to cisplatin resistance depending on the biological background of the cell system and presumably reflecting different pathways of apoptosis.
 ...
PMID:Role of apoptosis and apoptosis-related proteins in the cisplatin-resistant phenotype of human tumor cell lines. 1464 25

C-myc is an oncogene with the important role of cell proliferation controller. It has been found to be amplified and overexpressed in osteosarcoma. Moreover, it can promote cell transformation and induce metastatic features. Some studies showed that overexpression of c-myc could induce resistance in response to antineoplastic agents. Currently, we constructed the recombinant adenovirus (Ad-Asc-myc) encoding antisense c-myc fragment and investigated its effect on the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin(CDDP). The osteosarcoma MG-63 cells were transfected by the Ad-Asc-myc in vitro, and Western Blot, MTT assay, RT-PCR, flow cytometry (FCM), and transmission electron microscopy (TEM) were used to study expression of c-myc and caspase-3 protein, tumor cell proliferation in vitro, cell apoptotic morphology and cell cycle change. Ad-Asc-myc encoding antisense c-myc fragment was obtained with the titer of 2.0 x 10(9) pfu/ml. Ad-Asc-myc downregulated the expression of c-myc protein after transfected MG-63 cells for 48 hours, combined with the treatment of 2.0, 5.0 microg/ml cisplatin for 2 hours can inhibited tumor cells proliferation in vitro by 33.4 and 54.2 percent, respectively, which had significant difference compared with control recombinant adenovirus (Ad-LacZ) groups (P < 0.05). RT-PCR revealed that Ad-Asc-myc downregulated expression of bcl-2 and upregulated expression of Bax, and no appreciable changes were observed in the expression of E2F-1. Detection of caspase-3 protein TEM, and FCM analysis showed that Ad-Asc-myc could induce apoptosis of transfected cells, which was enhanced by the treatment of cisplatin. Cell cycle analysis showed that obvious G(2)/M phase arrested in transfected cells. In conclusion, Ad-Asc-myc increased the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin as well as induced apoptosis.
 ...
PMID:Recombinant antisense C-myc adenovirus increase in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin. 1646 85

Many researchers have reported that proteasome inhibitors could induce apoptosis in a variety of cancer cells, such as breast cancer cell, lung cancer cell, and lymphoma cell. However, the effect of proteasome inhibitors on osteocsarcoma cells and the mechanisms are seldom studied. In this study, we found proteasome inhibitor MG132 was an effective inducer of apoptosis in human osteosarcoma MG-63 cells. On normal human diploid fibroblast cells, MG132 did not show any apoptosis-inducing effects. Apoptotic changes such as DNA fragment and apoptotic body were observed in MG132-treated cells and MG132 mostly caused MG-63 cell arrest at G(2)-M-phase by cell cycle analysis. Increased activation of caspase-8, accumulation of p27(Kip1), and an increased ratio of Bax:Bcl-2 were detected by RT-PCR and Western blot analysis. Activation of caspase-3 and caspase-9 were not observed. This suggests that the apoptosis induced by MG132 in MG63 cells is caspase-8 dependent, p27 and bcl-2 family related.
 ...
PMID:Caspase-8 dependent osteosarcoma cell apoptosis induced by proteasome inhibitor MG132. 1749 42

Nitric oxide (NO) can regulate osteoblast activities. This study was aimed to evaluate the protective effects of pretreatment with sodium nitroprusside (SNP) as a source of NO on hydrogen peroxide-induced osteoblast insults and its possible mechanisms. Exposure of human osteosarcoma MG63 cells to hydrogen peroxide significantly increased cellular oxidative stress, but decreased ALP activity and cell viability, inducing cell apoptosis. Pretreatment with 0.3 mM SNP significantly lowered hydrogen peroxide-induced cell insults. Treatment of human MG63 cells with hydrogen peroxide inhibited Bcl-2 mRNA and protein production, but pretreatment with 0.3 mM SNP significantly ameliorated such inhibition. Sequentially, hydrogen peroxide decreased the mitochondrial membrane potential, but increased the levels of cytochrome c and caspase-3 activity. Pretreatment with 0.3 mM SNP significantly lowered such alterations. Exposure to hydrogen peroxide decreased Runx2 mRNA and protein syntheses. However, pretreatment with 0.3 mM SNP significantly lowered the suppressive effects. Runx2 knockdown using RNA interference inhibited Bcl-2 mRNA production in human MG63 cells. Protection of pretreatment with 0.3 mM SNP against hydrogen peroxide-induced alterations in ALP activity, caspase-3 activity, apoptotic cells, and cell viability were also alleviated after administration of Runx2 small interference RNA. Thus, this study shows that pretreatment with 0.3 mM SNP can protect human MG63 cells from hydrogen peroxide-induced apoptotic insults possibly via Runx2-involved regulation of bcl-2 gene expression.
 ...
PMID:Runx2-mediated bcl-2 gene expression contributes to nitric oxide protection against hydrogen peroxide-induced osteoblast apoptosis. 1974 47

To study the inhibitory effect and anti-cancer mechanisms of interleukin 24 (IL-24) on human osteosarcoma cell MG-63, we delivered IL-24 into MG-63 cells in vitro and in vivo by adenovirus. The expression level of IL-24 was detected by RT-PCR and fluorescence microscope; the growth inhibition, apoptosis rate and apoptosis body were measured by MTT, Flow cytometry and Hoechst staining respectively. Furthermore, we analyzed the expression of bcl-2, bax, caspase3 genes by RT-PCR after overexpression of IL-24. For in vivo study, we first established the MG-63 tumor model by grafting MG-63 cells in athymic nude mice; and then injected Ad-IL-24 into the tumors. Two weeks after injection, we sacrificed the mice, removed the tumors, weighed and calculated the ratios of tumor-suppression. We also detected the expressions of Bcl-2, Bax, Caspase-3 and CD34 with immumohistochemistry. Our in vitro results indicated that Ad-IL-24 was transcribed and translated in MG-63 osteosarcoma cells. More interestingly, IL-24 inhibited the growth of MG-63 cells and induced apoptosis by up-regulation of bax, caspase-3 and down-regulation of bcl-2. The in vivo data showed that IL-24 suppressed the tumor growth conspicuously through down-regulating the expression of bcl-2, and up-regulating the expression of bax, caspase-3. This study would provide evidence for the gene therapy of IL-24 on osteosarcoma.
 ...
PMID:[Interleukin 24 inhibits growth and induces apoptosis of osteosarcoma cells MG-63 in vitro and in vivo]. 2011 99

The bacterial redox protein azurin selectively induces apoptosis in human osteosarcoma U2OS cells. We constructed a p53 siRNA to test the role that p53 plays in the apoptosis-inducing role of azurin in U2OS cells. Cells treated with p53 siRNA and azurin showed more viable cells, a lower apoptosis rate, lower caspase-3 activity, and up-regulation of bcl-2, downregulation of bax compared to cells treated with negative siRNA and azurin. Cells treated with negative siRNA and azurin yielded positive TUNEL dying, whereas cells treated with p53 siRNA and azurin yielded few positive cells. These results suggested that p53 siRNA was capable of inhibi-ting the apoptosis induced by azurin 2 days after treatment with p53 siRNA and azurin. Azurin may induce apoptosis through combination with p53. The decrease in p53 protein levels did not inhibit cell apoptosis rates, but rather increased these rates in U2OS osteosarcoma cells 3 days after treatment with p53 siRNA. Since U2OS cells are p53 wild-type cancer cells, p53 potentially acts as an oncogene in U2OS osteosarcoma cells. Treatment with azurin may transform the function of p53 from inhibiting to inducing apoptosis.
 ...
PMID:p53 siRNA inhibits apoptosis of U2OS cells treated with azurin. 2182 38

Kruppel-like factor 6 (KLF6) is a tumor suppressor gene frequently downregulated in a number of human cancers, including osteosarcoma. However, the role of KLF6 in osteosarcoma remains unclear. This study was aimed at investigating the effects of KLF6 on osteosarcoma cell biological behavior. First, the expression of KLF6 in osteosarcoma cell lines (MG63, SaOS-2, U2OS, and HOS) and a human osteoblastic cell line (hFOB1.19) was detected by Western blotting. Results showed that KLF6 displayed a significant downregulation in osteosarcoma cell lines (MG63, SaOS-2, U2OS, and HOS) compared with human osteoblastic cell line (hFOB1.19). To investigate the role of KLF6 in osteosarcoma cell proliferation, apoptosis, and invasion, we generated human osteosarcoma MG63 cells in which KLF6 was either overexpressed or depleted. The MG63 cell viability, cycle, apoptosis, and invasive ability were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide staining, propidium iodide (PI) staining, Annexin-V-FITC/PI double staining, and Transwell invasion experiment, respectively. Results showed that the viability, proliferation, and invasive abilities were suppressed, and the apoptosis was enhanced in MG63 cells with overexpression of KLF6. The viability, proliferation, and invasive abilities were improved, and the apoptosis was inhibited in MG63 cells with knockdown of KLF6. At the same time, these molecules, including p21, bcl-2, and MMP-9, associated with the events about cell cycle, apoptosis, and invasion, were detected. Results showed that the expressions of bcl-2 and MMP-9 were downregulated, and the expressions of p21 were upregulated in the MG-63 cells with overexpression of KLF6. Taken together, our results suggested that KLF6 could inhibit proliferation and invasion, and facilitate apoptosis of osteosarcoma cells, which might be a potential target for the treatment of osteosarcoma.
 ...
PMID:Effects of Kruppel-like factor 6 on osteosarcoma cell biological behavior. 2332 24

Polysaccharides have shown great importance in cancer therapy. The current study showed that a polysaccharide from Dictyophora indusiata (PDI) also possessed anti-cancer properties. Methyl thiazolyl tetrazolium assay revealed a dose-dependent reduction of osteosarcoma S180 growth in response to PDI treatment. Apoptosis was observed following treatments with PDI, as reflected by the appearance of the subdiploid fraction and DNA fragmentations. We then investigated effects of PDI on expression of apoptosis-associated genes and the results revealed an increase of expression of bcl-2 and decreases of cdk4 and p53 protein levels. Finally, PDI treatment significantly increased the activation of caspase-3, a key executioner of apoptosis. These findings indicate that PDI may act as a chemopreventive and/or chemotherapeutic agent in osteosarcoma cells by reducing cell viability and inducing apoptosis.
 ...
PMID:Induction of apoptosis in osteosarcoma S180 cells by polysaccharide from Dictyophora indusiata. 2340 Sep 47

MicroRNA 181a (miR-181a) was found dysregulated in a variety of human cancers and significantly associated with clinical outcome of cancer patients. However, the direct role of miR-181a has not yet been characterized in osteosarcoma progression. This study was aimed at investigating the effects of miR-181a on osteosarcoma cell biological behavior. First, the expression of miR-181a in osteosarcoma cell lines (MG63, HOS, SaOS-2, and U2OS) and a human osteoblastic cell line (hFOB1.19) was detected by qRT-PCR. Results showed that miR-181a was overexpressed in osteosarcoma cell lines compared to human osteoblastic cell line (hFOB1.19). To investigate the effects of miR-181a on proliferation, apoptosis, and invasion of osteosarcoma cells, we generated human osteosarcoma MG63 cells in which miR-181a was either overexpressed or depleted. The MG63 cell viability, cycle, apoptosis, and invasive ability were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide staining, propidium iodide (PI) staining, Annexin V-FITC/PI double staining, and Transwell invasion experiment, respectively. The results showed that MG63 cell viability, proliferation, and invasive abilities were suppressed, and the apoptosis was enhanced in the group with underexpression of miR-181a. The viability, proliferation, and invasive abilities were improved, and the apoptosis was inhibited in the group with overexpression of miR-181a. The results from Western blotting indicated that miR-181a might be associated with the up-regulation of bcl-2 and matrix metalloproteinase 9 and the down-regulation of tissue inhibitor of metalloproteinases-3 and p21 in MG63 cells. Taken together, our results suggested that miR-181a might facilitate proliferation and invasion and suppress apoptosis of osteosarcoma cells, which might be a potential target for the treatment of osteosarcoma.
...
PMID:MicroRNA 181a improves proliferation and invasion, suppresses apoptosis of osteosarcoma cell. 2374 Jun 15

bcl-2 is a member of the bcl-2 family that inhibits apoptosis, plays a crucial role in cell viability and is expressed in various types of tumors. With respect to inconsistent results in previous studies, the aim of the present study was to generate a clear hypothesis with regards to the value of bcl-2 expression as a predictive or prognostic factor in human osteosarcoma. The expression of bcl-2 was examined immunohistochemically in 49 patients with high-grade osteosarcoma and the results were correlated with localization, histological response to chemotherapy, survival and the occurrence of metastases. In patients with osteosarcoma, 21/49 cases (43%) were positive for bcl-2 expression and the remaining cases were negative. A significantly higher expression of bcl-2 was observed in central tumors located in the pelvis (83 vs. 37% positive; P<0.05). The bcl-2 expression status revealed no statistically significant correlation with response to chemotherapy, with 57% of patients with bcl-2-positive tumors showing a good response and 43% showing a poor response. No significant difference was observed when comparing survival or occurrence in bcl-2-positive and -negative tumors. In conclusion, the results of the present study indicate that, despite higher bcl-2 expression in central osteosarcoma, the expression in high-grade osteosarcoma is not a reliable prognostic or predictive marker.
 ...
PMID:Bcl-2 correlates with localization but not outcome in human osteosarcoma. 2413 69


<< Previous 1 2 3 Next >>