Up-regulation of T-lymphoma and metastasis gene 1 in gastric cancer and its involvement in cell invasion and migration / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>T-lymphoma and metastasis gene 1 (Tiam1) produces a guanine nucleotide exchange factor (GNEF) that regulates guanosine triphosphatase, which transforms guanosine diphosphate to guanosine triphosphate. Recently published data indicate that Tiam1 was associated with gastric cancer. The aim of this study was to investigate biological effects and potential mechanisms of Tiam1 in gastric carcinoma.</p><p><b>METHODS</b>We analyzed the expression of Tiam1 in 114 pair-matched gastric neoplastic and adjacent non-neoplastic tissues by quantitative real-time PCR. We investigated Tiam1 expression and its prognostic value for gastric cancer. Furthermore, the functions of Tiam1 over-expression were analyzed with stable-expression Tiam1 plasmid in human gastric cancer cell lines.</p><p><b>RESULTS</b>Tiam1 expression was significantly associated with cell differentiation and lymphatic metastasis; expression of Tiam1 mRNA was up-regulated in gastric cancer compared to pair-matched adjacent non-tumor tissues. Analyses of surgical tissue samples and 5-year survival of gastric cancer patients showed that those with strong Tiam1 expression had significantly shorter overall survival time than those with negative Tiam1 expression. Ectopic expression of Tiam1 promoted cell growth, migration and invasion of gastric cancer cells in vitro.</p><p><b>CONCLUSIONS</b>In gastric cancer cells, Tiam1 affects multiple properties associated with acquisition of the metastatic phenotype, and may be a marker of gastric cancer progression and metastasis in a subset of cancer.</p>

Effects of RNA interference and nolatrexed on thymidylate synthase expression and cell proliferation of human colorectal carcinoma LOVO cells / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the effect of the RNAi and the chemotherapy drugs nolatrxed on the expression of thymidylate synthase(TS) and the growth of the colorectal carcinoma LOVO cells.</p><p><b>METHODS</b>The siRNA was constructed targeting the human TS gene, and then transfected into the human colorectal cancer LOVO cells. RT-PCR and Western blot technique were used to observe the TS gene and protein expression levels, and MTT was used to detect cell proliferation after silencing the TS gene. In addition, siRNA and nolatrxed were applied to the LOVO cells to observe the TS protein expression and cell growth.</p><p><b>RESULTS</b>TS siRNA significantly reduced the expression of TS gene and protein in LOVO cells, and inhibited cell growth. The IC50 value of LOVO cells was (1.46±0.25) μmol/L in TS siRNA combined with nolatrexed group, (6.81±0.31) μmol/L in the negative control group, and (6.47±0.43) μmol/L in the single nolatrexed group. After treatment of TS siRNA combined with nolatrexed on LOVO cells for 36 hours, the apoptosis index was higher than that in single TS siRNA and nolatrexed[(62.12±0.89)% vs.(21.56±0.67)% and(40.51±0.83)%, both P<0.05].</p><p><b>CONCLUSION</b>TS siRNA can partly suppress the expression of TS gene in LOVO cells, inhibit cell proliferation, promote cell apoptosis and enhance cell sensitivity to apoptosis induced by nolatrexd.</p>