Objective To study the mechanisms of Hydroxycamptothecin (HCPT) induced apoptosis of gastric cancer cells by detecting the expressions of p53, c myc, bcl 2, bcl xl, bcl xs genes. Methods Apoptosis of gastric cancer cells (SGC 7901,MKN 45) was measured by TUNEL and flow cytometry. The levels of mRNA and protein of p53, c myc, bcl 2, bcl xl,bcl xs genes were determined by reverse transcriptase polymerase chain reaction analysis and immunohistochemistry, respectively. Results Gastric cancer cells SGC 7901, MKN 45 presented some morphologic features of apoptosis, including cell shrinkage, nuclear condensation, DNA fragmentation, formation of apoptotic bodies, after 12 hours expourse to HCPT. Some typical subdiploid peaks before G0/G1 phase were observed. The apoptotic rates of SGC 7901, MKN 45 were 21.88% and 12.34%, respectively. The levels of p53 and bcl 2 mRNA and protein were downregulated after treated with HCPT in SGC 7901 cells. The levels proteins of c myc, bcl xl, bcl xs were unchanged after expourse to HCPT in SGC 7901 cells. The levels of p53 mRNA and protein were increased after treated with HCPT in MKN 45 cells. While the expressions of protein of bcl 2, c myc, bcl xl, bcl xs genes were not affected by HCPT in MKN 45 cells. Conclusion The results have showed HCPT induced apoptosis in gastric cancer cells might be regulated through influencing the expressions of p53 and bcl 2 genes.

Objective To construct recombinant plasmid pEGFP C1 antisense survivin and than transfect it to MKN 45 gastric cancer cells for studying the expression of survivin mRNA and its effects on apoptosis of cancer cells. Methods Recombinant pEGFP C1 antisense survivin plasmid was cloned and transfected to MKN 45 gastric cancer cells by lipofectamine. Apoptosis of gastric cancer cells was assayed by flow cytometry. The levels of survivin mRNA before and after transfection were determined by reverse transcription polymerase chain reaction analysis. Results After recombinant pEGFP C1 antisense survivin plasmid was transfected, the apoptosis of MKN 45 cells was increase, the cell number in G 2/M phase was decreased, and the level of survivin mRNA was inhibited. Conclusions pEGFP C1 antisense suvivin can promote the apoptosis of MKN 45 gastric cancer cells, that might attribute to the inhibition on cell proliferation and expression of survivin mRNA.

Objective Through gene reconstruction we generated pcDNA 3-survivin-mutant(Cys84Ala)plasmid, then the plasmid DNA was further transfected into gastric carcinoma cells by liposomal delivery. The effects of mutant survivin on cytokinetics of the gastric carcinoma cells were obversed. Methods By using immunohistochemical staining, the expression of survivin was detected in the gastric cancer tissues, and apoptosis was detected by flow cytometry. The PARP and cytochrome C expressions were determined by Western blot, the mitotic catastrophe was determined by immunofluorescence. Results Inhibition of survivin by mutant survivin cDNA could induce apoptosis, increase caspase-3 activity, cleave PARP and promote cytochrome C release in gastric cancer cells. Inhibition of survivin also caused mitotic catastrophe in gastric cancer cells. Conclusion Inhibition of survivin may induce apoptosis and mitotic catastrophe in gastric cancer. Survivin targeting gastric cancer therapy might be of potential benefit in the future.

Objective To investigate the inhibitory effect of X-linked inhibitor of apoptosis associated factor-1(XAF1) on xenograft growth in nude mice with hepatocellular carcinoma. Methods The models of xenografted nude mice with human hepatocellular carcinoma cell line SMMC7721 were established. Intratumor injection was performed on three tumor sites in each group of mice (n=5) with recombinant adenovirus Ad5/F35-XAF1, control virus Ad5/F35-Null at the same infective titre or PBS of the same volume every two days for two weeks. The volumes of xenografts in all nude mice were measured every three days, and the differences between Ad5/F35-XAF1 group and the other two groups were compared. The apoptosis of tumor cells was determined by in situ end-labeling TUNEL method, the expression of XAF1 protein and microvessel density (MVD) were detected by immunohistochemistry. Results Intratumoral injection of Ad5/F35-XAF1 significantly inhibited the growth of tumor xenografts with smaller tumor size, less tumor weight and lower MVD compared with those injected with control virus Ad5/F35-Null and PBS (P<0.05 or P<0.01). However, the apoptosis index and expression of XAF1 protein in Ad5/F35-XAF1 group were significantly increased compared with the other two groups (P<0.01). Conclusion Ad5/F35-XAF1 significantly inhibits xenograft growth in nude mice with hepatocellular carcinoma, which is probably associated with the effects of XAF1 inducing hepatocellular carcinoma cell apoptosis and suppressing tumor angiogenesis.

Objective Survivin is overexpressed in gastric cancer. However it not expressed in normal gastric mucosa. The expression of survivin is tightly related to the prognosis of gastric cancer.By gene reconstruction we generated pcDNA3 survivin mutant(Cys84Ala) plasmid, and observed its effect on the gastric carcinoma cell lines. Methods The survivin mRNA and protein expression levels were determined by reverse transcription polymerase chain reaction(RT PCR) analysis,Western blot and immunohistochemical staining respectively . Flowcytometry and acridine orange staning were employed to detect apoptosis. Results Overexpression of survivin mRNA and protein were detected in the gastric cancer cell lines. Inhibition of survivin by survivin mutant cDNA induced apoptosis,activated caspase 3 activity,cleaved PARP and promoted cytochrome C releasing in gastric cancer cells,and effectively sensitized gastric cancer cells to chemotherapeutic agents. Conclusion Inhibition of survivin may induce apoptosis in gastic cancer and sensitize gastric cancer cells to chemotherapeutic agents.Survivin targeted therapeutic protocol may potentially benefit gastric cancer therapy.

Objective To investigate the possible signal pathway of the apoptosis in gastric cancer cell lines(SGC 7901 and MKN 45)induced by arsenic trioxide. Methods TUNEL method was used to observe the influence of calcium antagonist, inhibitors of protein kinase C (PKC) and protein tyrosine kinase(PTK) on the apoptosis of gastric cancer cells induced by arsenic trioxide. Levels of cAMP, PKC and PTK were detected before and after the treatment with arsenic trioxide. Results Both PKC and PTK inhibitors could induce apoptosis of gastric cancer cell lines, also both of them had a cooperative action with arsenic trioxide in inducing apoptosis of gastric cancer cells, while calcium antagonist had no any effect on the apoptosis of gastric cancer cell lines. PKC and PTK levels decreased but cAMP level increased during the apoptosis of gastric cancer cells induced by arsenic trioxide ( P