• The Journal of the Korean bone and joint tumor society
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• v.7 no.2
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• pp.64-67
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• 2001

Epithelioid sarcoma has been well characterized as a distincitve entity. In the classic form, it occurs in the distal extremities of young adults. However, in the proximal form, it was found mostly in the pelvis, perineum, and genital tract of young to middle-aged adults. Morphologically, the tumor cells had promient epithelioid or rhabdoid features with marked cytologic atypia, and grew in a multinodular pattern. Immunohistochemically, cytokeratin, epithelial membrane antigen, and vimentin were positive in the tumor cells. This reports dealt with 32-year-old male lesion on his perineum. The tumor shows typical features of proximal type epithelioid sarcoma. We also discussed pathological differential diagnosis and prognosis on this particular disease.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.4
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• pp.143-151
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• 2000

Purpose : The p53 tumor suppressor gene is one of the most frequently altered genes in human malignancies. We try to explore the implication of p53 alteration in Ewing's sarcoma. Materials and Methods : We analyzed 35 paraffin blocks to explore the deletion and sequence alterations of p53. Results : Quantitative PCR analysis showed that 2 tumors showed a homozygous deletion of the gene. Mutational analysis of exons 4 to 9 of p53 by PCR-SSCP revealed that 3 tumors carry sequence alterations in exons 5 or 8, and DNA sequencing analysis identified missense point mutations. Conclusion : Taken together, our data demonstrate that p53 is genetically altered in a small fraction of Ewing's sarcoma.

• Journal of Oral Medicine and Pain
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• v.35 no.3
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• pp.165-175
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• 2010

Valproic acid (VPA) is a well-known anticonvulsive agent and has been used in the treatment of epilepsy for almost 30 years. VPA emerged in 1997 as an antineoplastic agent as well, when findings indicated the substance inhibited proliferation and induced differentiation of primitive neuroectocdermal tumor cells in vivo (Cinatl et al., 1997). Antitmor activity of VPA is associated with its targeting histone deacetylases. Bile acids and their synthetic derivatives induced apoptosis in various kinds of cancer cells and anticancer effects. It has been reported that the synthetic chenodeoxycholic acid (CDCA) derivatives showed apoptosis-inducing activity on various cancer cells in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with the histone deacetylases inhibitor, VPA and a CDCA derivative, HS-1200 on human osteosarcoma (HOS) cells. Cell viability was evaluated by trypan-blue exclusion. Induction and augmentation of apoptosis were confirmed by Hoechst staining, flow cytometry (DNA hypoploidy and MMP change), Westen blot analysis and immunofluorescent staining. In this study, HOS cells co-treated with VPA and HS-1200 showed several lines of apoptotic manifestation such as nuclear condensations, the reduction of MMP, the decrease of DNA content, the release of cytochrome c into cytosol, the translocation of AIF onto nuclei, and activation of caspase-7, caspase-3 and PARP whereas each single treated HOS cells did not. Although the single treatment of 1 mM VPA or $25\;{\mu}M$ HS-1200 for 48 h did not induce apoptosis, the co-treatment of them induced prominently apoptosis. Therefore our data provide the possibility that combination therapy of VPA and HS-1200 could be considered as a novel therapeutic strategy for human osteosarcoma.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.11-20
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• 2011

Valproic acid (VPA) is a well-known anticonvulsive agent and has been used in the treatment of epilepsy for almost 30 years. VPA emerged in 1997 as an antineoplastic agent. And it is known that antitmor activity of VPA is associated with its targeted at histone deacetylases. 17AAG, Inhibition of HSP90 leads to the proteasome degradation of the HSP90 client proteins, such as Akt, Raf/Ras, Erk, VEGF, cyclin D and p53, and causes potent antitumor activity. It is reported that 17AAG-induced HSP90 inhibition results in prevention of cell proliferation and induction of apoptosis in several types of cancer. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with the histone deacetylases inhibitor, VPA and the HSP90 inhibitor, 17AAG on human osteosarcoma (HOS) cells. Cell viability was evaluated by trypan-blue exclusion. Induction and augmentation of apoptosis were confirmed by Hoechst staining, flow cytometry (DNA hypoploidy and MMP change), Westen blot analysis and immunofluorescent staining. In this study, HOS cells co-treated with VPA and 17AAG showed several lines of apoptotic manifestation such as nuclear condensations, the reduction of MMP, the decrease of DNA content, the release of cytochrome c into cytosol, the translocation of AIF onto nuclei, and activation of caspase-3, caspase-7 and PARP whereas each single treated HOS cells did not. Although the single treatment of 1 mM VPA or 0.5 ${\mu}M$ 17AAG for 48 h did not induce apoptosis, the co-treatment with them induced prominently apoptosis. Therefore our data in this study provide the possibility that combination therapy with VPA and 17AAG could be considered as a novel therapeutic strategy for human osteosarcoma.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.1
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• pp.23-29
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• 2011

Purpose: We investigated the effects of phosphatase and tensin homologue deleted on chromosome 10 gene phosphatase and tensin homologue deleted on chromosome 10 gene (PTEN) expression on the cell proliferation and on the responsiveness of troglitazone in osteosarcoma cells. Materials and Methods: Western blotting alnalysis was performed to detect the expression of PTEN in U-2OS cells treated with troglitazone. WST (water-soluble tetrazolium) assay was used to evaluate cell proliferation. Flow cytometry was used to determine cell apoptosis. Further, transfection of wild-type PTEN plasmid DNA was used to upregulate PTEN expression. Results: Troglitazone treatment induced growth inhibition of U2-OS cells in a dose- and time-dependent manner. Troglitazone increased the expression of PTEN in a dose-dependent manner. PTEN upregulation induced by troglitazone treatment resulted in cell growth inhibition and apoptosis in U-2OS cells. PTEN over-expression by plasmid transfection enhanced these effects of troglitazone. Moreover, no changes were observed in the mutant type-PTEN group. Conclusion: Upregulation of PTEN is involved in the inhibition of cell growth and induction of cell apoptosis by troglitazone. Further, PTEN over-expression can cause cell growth inhibition in osteosarcoma cells and these cell growth inhibitions could be enhance by troglitazone treatment.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.3
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• pp.162-168
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• 1999

The products of c-fos and c-jun proto-oncogenes form the heterodimeric complex activator protein 1 (AP-1), which plays an important part in the control of bone cell proliferation and differentiation, as well as in the development of bone tumors. The expression of c-fos protein was examined in 35 cases of human osteosarcomas as formalin-fixed paraffin-embedded tissue sections using a monoclonal antibody. The expression of c-fos was restricted to bone-forming lesions, while low grade cartilaginous tumors were devoid of immunoreactivity. The highest levels of c-fos expression were detected in osteoblastic osteosarcoma (13 of 17 cases with grade one on two) while two chondroblastic osteosarcomas, one fibroblastic osteosarcoma, and two parosteal osteosarcomas were negative. Two cases of telangiectatic osteosarcomas were positive for c-fos protein. However, since there is a tendency of high c-fos protein expression at the higher histological grade, significant differences were not present in the expression of c-fos protein. Thus c-fos expression may be implicated in the development of osteosarcomas, but they appear to have little or no relevance in the development of low grade cartilaginous neoplasms.