• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.221-233
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• 2013

Bile acids are polar derivatives of cholesterol essential for the absorption of dietary lipids and regulate the transcription of genes that control cholesterol homeostasis. Recently it have been identified the synthetic chenodeoxycholic acid (CDCA) derivatives HS-1200 and cisplatin showed apoptisis-inducing activity on various cancer cells in vivo and in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with HS-1200 and cisplatin on human tongue squamous cell carcinoma cells (SCC25 cells). To investigate whether the co-treatment with HS-1200 and cisplatin compared to each single treatment efficiently reduces the viability of SCC25 cells, MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis DNA hypoploidy. Westen blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. In this study, co-treatment with HS-1200 and cisplatin on SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, reduction of MMP and proteasome activity, the increase of Bax and the decrease of Bcl-2, decrease of DNA content, the release of cytochrome c into cytosol, translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD) whereas each single treated SCC25 cells did not show these patterns. Although the single treatment of $25{\mu}M$ HS-1200 and $4{\mu}g/ml$ cisplatin for 24 h did not induce apoptosis, the co-treatment of these reagents prominently induced apoptosis. Therefore our data provide the possibility that the combination therapy with HS-1200 and cisplatin could be considered as a novel therapeutic strategy for human squamous cell carcinoma.

• 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.