Background: Immune cells recognize tumor antigens presented on major histocompatibility complex class I (MHC-I) molecule. Increase of MHC-I molecular expression makes tumor cells more susceptible to lysis by immune cells.Methods: Tumor lysate vaccine was prepared to damage glioma cells including cell lines and primary cultured cells from surgical samples. The enhanced effect of histone deacetylase inhibitors (HDACi) to tumor lysate vaccine was observed. The expressions of MHC-I pathway molecules were detected by flow cytometry and western blot after HDACi treatment. Cell apoptosis and cell lysis were measured following blocking cytotoxic T lymphocyte (CTL) pathway. Tumor size and mice survival were analyzed in combinative treatment with HDACi and tumor lysate.Results: HDACi up-regulated the expressions of MHC-I pathway molecules, and enhanced the recognition and killing of immune cells, which was activated by tumor lysate. Activated antigen specific immune responses regulated CTL activity, and HDACi promoted immune response through cytotoxic effect of CTL. Anti-tumor effect of tumor lysate pulse immunogenicity in vivo was elevated by HDACi due to up-regulation of antigen presentation.Conclusions: Our study showed that HDACi enhanced recognition of glioma cell by immune cells and sensitivity of tumor immunotherapy, and improved the anti-tumor effect of tumor lysate vaccine through activating CTL immune response. These pharmacological molecular mechanisms of increasing immune recognition suggest that epigenetic modulation is a promising strategy for sensitizing immunotherapy for glioma treatment.

Transforming growth factor-β (TGF-β) has been shown to induce apoptosis in normal hepatocytes and hepatoma cells both in vivo and in vitro. However, the mechanism by which TGF-β induces apoptosis is not clear. The antiapoptotic activity of antioxidants including N-acetyl-L-cysteine (Ac-Cys), ascorbic acid and a novel free radical scavenger, carboxyfullerene (C 60 ) on TGF-β-treated human hepatoma Hep3B cells was examined. Only the water-soluble hexacarboxylic acid derivative of C 60 was found to prevent TGF-β-induced apoptosis. Antiapoptotic activity of C 60 correlated its ability to eliminate TGF-β-generated reactive oxygen species (ROSs). However, C 60 did not interfere with TGF-β-activated PAI-1 promoter activity in the Hep3B cells. These results indicate that the signaling pathway of TGF-β-induced apoptosis may be related to the generation of ROSs and may be uncoupled from the TGF-β-activated gene promoter activity. Furthermore, the regioisomer of C 60 with a C 3 symmetry was more potent in protecting cells from apoptosis than that with a D 3 symmetry, and the C3 isomer had stronger interactions with lipid bilayers than the D 3 isomer. The spectroscopic analysis revealed that the C 3 isomer had stronger interactions with artificial lipid bilayers than the D 3 isomer. Therefore, our study indicates that C 60 may interact with membrane to eliminate TGF-β-induced ROSs and to prevent apoptosis occur in human hepatoma cells.Keywords : carboxyfullerene ; transforming growth factor-β ; apoptosis ; reactive oxygen species.Since its discovery, the pure carbon spheres of buckminster-inhibits cell proliferation, depending on the cell types and the presence of other growth factors [7Ϫ11]. Recent studies have fullerene (C 60 ) have generated great interest from many different branches of science and engineering. To investigate the chemical shown that TGF-β induces apoptosis in liver cells in vitro [12Ϫ 17], and transgenic mice overexpressing TGF-β develop continand physical characteristics of C 60 (and its larger fullerenes), many novel properties of C 60 were observed including its avid uing apoptotic death of hepatocytes as well as hepatic fibrosis in vivo [18]. Exogenous administration of TGF-β to rodents also reactivity with free radicals [1]. Buckminsterfullerenes, for example, are capable of adding multiple radicals to each molecule. results in a significant increase in hepatic cell death [13,15,19].These data strongly suggest that apoptosis induced by TGF-β The addition of as many as 34 methyl radicals to a single C 60 sphere has been reported, leading Krusic et al.[1] to characterize may be involved in various hepatic lesions. However, despite the identification of TGF-β receptors and the genes involved in C 60 as a 'radical sponge'. However, native C 60 is soluble only in organic solvents. Dugan et al. [2] have evaluated the possibility its downstream signaling pathway [20Ϫ27], the mechanism of TGF-β-induced apoptosis remains largely unknown. that the potent innate anti-oxidant properties of C 60 could be harn...

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Transforming growth factor-β (TGF-β) has been shown to induce apoptosis on normal hepatocytes and hepatoma cells both in vitro and in vivo. However, how the TGF-β induces apoptosis is still not clear. We examined the expression of anti-apoptosis proteins and sensitivity to TGF-β in three well differentiated human hepatoma cell lines. Two TGF-β sensitive cell lines Hep3B and HuH7 totally lacked Bcl-2. In contrast, the TGF-β resistant HepG2 cells expressed a substantial amount of Bcl-2. All three cell lines expressed equal amounts of Bcl-X_L, Bcl-X_S and Bax. Overexpression of Bcl-2 in Hep3B and HuH7 cells protected them from TGF-β-induced apoptosis. TGF-β treatment increased intracellular peroxide production and suppressed the expression of glutathione-S-transferase in the Hep3B cells, and these effects were partially suppressed by the overexpression of Bcl-2. These results suggest that Bcl-2 may protect cell from TGF-β-F-induced apoptosis by interfering TGF-β generated signals leading to induce reactive oxygen species production.