Susceptibility for NSAIDs-induced apoptosis correlates to p53 gene status in gastric cancer cells.

The anti-tumor effect of non-steroidal anti-inflammatory drugs (NSAIDs) remains unclear. Here, we found that the susceptibility for NSAIDs-induced apoptosis might correlate with the status of the p53 gene in gastric cancer cells. Apoptosis in gastric cancer cells expressing wild-type p53 is induced through up-regulation of bax and down-regulation of bcl-2 and that regulation of the bax-bcl-2 heterodimer may be a major target of NSAIDs. As to gastric cancer cells expressing mutant-type p53, other key factors may exist in the NSAIDs' growth inhibition action.

[The relationship of mTOR signaling pathway and histone acetylation in human gastric cancer cell lines].

OBJECTIVE: To evaluate the relationship between mammalian target of rapamycin (mTOR) signaling pathway and histone acetylation in cell survival, cell cycle, gene expression and protein level on human gastric cancer cells. METHODS: Human gastric cancer cell lines, MKN45 and SGC7901 were treated with trichostatin A, rapamycin and/or LY294002, a PI3K inhibitor. Cell viability was analyzed by methylthiazolyl tetrazolium. Cell cycle distribution was evaluated by flow cytometry. The transcription level of p21(WAF1) gene was detected by using real-time polymerase chain reaction. Proteins were detected by Western blotting. RESULTS: Cell viability remarkably reduced after treatment by more than two drugs (P< 0.01). Through flow cytometry assessment, MKN45 cells were arrested in G2 phase (P< 0.05), while SGC7901 cells were in G2 or G1 phase (P< 0.05) whether treated with single or more than two drugs. The expression of p21(WAF1) mRNA was remarkably increased in the gastric cancer cells treated with conjoined drugs (P< 0.01). Phosphorylation of Akt, p70S6K and 4E-BP1 was significantly reduced in cells treated with conjoined drugs (P< 0.01). And histone acetylation of H4/H3 was also increased in cells treated with conjoined drugs (P< 0.01). CONCLUSION: mTOR singnaling pathway has an important relationship with histone acetylation in gastric cancer cell lines. There is a co-effect of mTOR inhibitor and histone deacetylase inhibitor on gastric cancer cells.

[Expression of endotoxin receptors on hepatic stellate cells during their activation].

OBJECTIVE: To investigate the role of endotoxin receptor expression in the activation of hepatic stellate cells (HSCs). METHODS: HSCs were isolated from normal rats and the expression of endotoxin receptors on quiet HSCs and in vitro activated HSCs was determined using RT-PCR and immunocytochemical staining methods. A rat model of liver fibrosis and cirrhosis was established. The expressions of CD14 and alpha-SMA in liver tissues were detected by immunohistochemical staining. RESULTS: Freshly isolated HSCs had a low level of CD14 mRNA expression and no expression of TLR4 mRNA was detected. The in vitro activated HSCs had increased expressions of CD14 mRNA and TLR4 mRNA and LPS up-regulated the expression of endotoxin receptors. Immunocytochemical staining showed cytoplasmic and nucleolus staining for CD14 in the cultured HSCs. LPS played a further role on CD14 protein expression. In the development of liver fibrosis, the number of CD14-positive cells in the livers was increased and these cells were distributed along the sinusoids. In the later stage of liver fibrosis, the CD14-positive cells were gathered in the fibrotic septae, which also contained alpha-SMA positive cells. CONCLUSION: The activated HSCs expressed endotoxin receptors. The endotoxin receptors may be involved in the role in which HSCs played in the inflammatory process and liver fibrosis development.

[Effect of eukaryotic expression plasmid DNA methyltransferase gene on methylation status and transcription level of DNA mismatch repair genes in human colon cancer cell line].

OBJECTIVE: To analyze the effect of eukaryotic plasmids containing sense or antisense DNA methyltransferase (Dnmt1) genes on the methylation status and transcription level of DNA mismatch repair (MMR) genes and microsatellite instability (MSI) in human colon cancer cell line. METHODS: Human colorectal cells of the SW1116 line were cultured. Recombinant plasmids containing sense Dnmt1 (HMT) or antisense Dnmt1 (THM) gene, pCMV-HMT and pCMV-THM, were constructed. Then pCMV-HMT, pCMV-THM, and pcMV blank plasmid were transfected into SW1116 cells respectively by using lipofectAMINE. The expression of Dnmt1 protein was examined by Western blotting. The transcription levels of hMLH1 and hMSH2 genes were detected by using real-time (RT-PCR). The status of methylation in promoters of hMLH1 and hMSH2 genes were examined with methylation specific PCR (MSP). The MSI of DNA in SW1116 cells was evaluated by silver-stained polyacrylamide gel electrophoresis. RESULTS: Both the expressions of the hMLH1 and hMSH2 gene mRNAs were remarkably decreased in the SW1116-HMT cells in comparison with those in the untransfected cells. The expression of hMSH2 gene mRNA in the SW1116-THM cells was remarkably increased in comparison with that in the untransfected cells. No significant difference in the expressions of the hMLH1 and hMSH2 gene mRNAs was found between the SW1116 cells transfected with blank pCMV and the untransfected SW1116 cells. MSP showed that the methylation level in the regions of hMLH1 and hMSH2 promoters was remarkably increased in the SW1116 cells transfected with sense Dnmtl plasmid. However, in the SW1116 cells the hMSH2 promoter region was changed from partially-methylated into de-methylated, and the hMLH1 promoter region remained non-methylated. MST test showed that extra bands indicating MSI were seen only in the D2S123 groups. CONCLUSION: Dnmt1 regulates the expression and methylation status of MMR genes and affects MSI in human colon cancer cell line SW1116.

[Effect of T-cell vaccination in murine experimental autoimmune hepatitis].

OBJECTIVE: To investigate the effect of T-cell vaccination in murine experimental autoimmune hepatitis (EAH). METHODS: To induce the EAH model, the syngeneic S-100 antigen emulsified in complete Freud's adjuvant was injected intraperitoneally to C57Bl/6 at day 1 and day 7. For T-cell vaccination, splenocytes were removed from animal 2 weeks after induction of EAH and from control animals, and activated in vitro by mitogen stimulation with Concanavalin A (Con A), then inactivated by mitomycin and injected at 5 10(7) cells per animal as T-cell vaccination at 14 and 7 days before first induction of EAH. RESULTS: The histological grade and serum ALT level of the mice who received T-cell vaccination were decrease significantly, compared with that of model group (1.44+/-0.88 vs. 2.33+/-0.87, t=2.24, P<0.05; 63.0U/L+/-23.4U/L vs. 115.0U/L1+/-39.6U/L, t=2.37, P<0.01, respectively); there was no significant change in mice who received irrelevant T-cell vaccination. CONCLUSION: T-cell vaccination with T cells from EAH animals, but not with irrelevant T cells, was able to protect animals from EAH.