Effect of siRNA for mutant p53 gene on biological behavior of gastric cancer cell line SGC7901 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of silencing the expression of mutant p53 gene with RNA interference technique on biological behavior of gastric cancer SGC7901 cells.</p><p><b>METHODS</b>Recombinant plasmid of mutant p53 gene-targeting siRNA was transfected into gastric cancer SGC7901 cells by Lipofectamine(TM)2000. The expressions of mutant p53 gene mRNA and protein were identified by RT-PCR and Western blot assay. The proliferation of SGC7901 cells and changes of Oxaliplatin (OXA) drug sensitivity were detected by MTT assay. The cell cycle distribution and apoptosis rate were analyzed by flow cytometry. Changes in cell tumorigenicity ability were analyzed by colony formation assay and xenograft tumor formation in nude mice.</p><p><b>RESULTS</b>The expression of mutant p53 in SGC7901 cells was remarkable suppressed by mutant p53-siRNA. The cell growth curve of the transfected group turned to left compared to untransfected group and control group. The cell number of G(0)/G(1) phase of transfected group was decreased by 7.4% and 6.7% respectively, and that of S phase was increased both by 17.2% compared to control group and untransfected group, and the cell apoptosis rate induced by Oxaliplatin was remarkable decreased. The IC(50) of OXA in untransfected group, control group and transfected group were 15.88 μmol/L, 14.32 μmol/L and 20.34 μmol/L respectively. The colony formation rate and tumorigenicity ability in nude mice of transfected group increased remarkably.</p><p><b>CONCLUSION</b>Mutant p53-siRNA can significantly inhibit the expression of mutant p53 in SGC7901 cells, however, the use of RNA interference targeting mutant p53 gene in the treatment of gastric cancer is still uncertain.</p>

Relation between mutant p53 and multidrug resistance in gastric cancer / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To explore the relationship between mutant p53 and multidrug resistance in gastric cancer.</p><p><b>METHODS</b>Mutant p53 (mp53) and mp53+sv40Tag were transferred to gastric cancer cell line SGC-7901. The MDR-1 mRNA was examined using RT-PCR, and the difference in chemotherapeutic sensitivity of SGC-7901 cells with mutant p53 was compared with those with mp53+sv40Tag and controls by MTT method.</p><p><b>RESULTS</b>SGC-7901 cells with mutant p53 showed higher MDR-1 mRNA than that of other two groups. SGC-7901 cells with mutant p53 showed higher chemotherapeutic sensitivity to 5-Fu than that with mp53+sv40Tag and control (P<0.05), but no difference between those with mp53+sv40Tag and control (P>0.05). SGC-7901 cells with mutant p53 and those with mp53+sv40Tag showed higher chemotherapeutic sensitivity to ADM than control (P<0.05), but no difference between those with mp53 and with mp53+sv40Tag (P>0.05). There was no difference in chemotherapeutic sensitivity of SGC-7901 cells with mutant p53 compared with those with mp53+sv40Tag and control to CDDP (P>0.05).</p><p><b>CONCLUSION</b>Mutante p53 genes relates to multidrug resistance of gastric cancer.</p>

Determination of theophylline concentration in serum by chemiluminescent immunoassay / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>This study aimed to establish chemiluminescent immunoassay (CLIA) for quantitative determination of theophylline levels in human serum.</p><p><b>METHODS</b>To measure the concentration of theophylline (n=122) and evaluate the assay.</p><p><b>RESULTS</b>The linear range of the CLIA method was 0.51-40 mg/L (Y=1.02X+0.44, r=0.995). The intra and inter CV (coefficient variance) of CLIA were 3.20% and 3.57%, respectively. The average recovery rate was 102.3%. This method was free from interference by brilirubin (<200 micromol/L), hemoglobin (<10 g/L), and triglycerides (<15 mmol/L).</p><p><b>CONCLUSION</b>This method is simple, convenient and precise for clinical pharmacokinetics study of theophylline.</p>