Abstract: Object: To investigate whether oridonin can enhance the antitumor effect of gemcitabine on pancreatic cancer SW1990 cells in vitro and explore the potential mechanism of its action. Methods: The pancreatic cancer SW1990 cells were treated with vehicle alone and various concentrations (10、20、40、80、160 μmol/L) of oridonin, followed by 24、48 and 72 h cell culture, Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit; SW1990 cells were treated with oridonin (40 μmol/L) and gemcitabine(20 μmol/L) alone or together for 48 h, with the untreated cells used as the contro1; the survival rate of cells was detected by CCK-8 assay. Apoptosis induction was assessed by using Annexin V-FITC kit; Semi-quantitative RT-PCR was used to examine the changes of NF-κB mRNA and XIAP mRNA expressions. Results: Oridonin inhibited the growth of pancreatic cancer SW1990 cells in a dose- and time-dependent manner. Compared with the other groups, the cell survival rate of the combination group was significantly lowered (P < 0.05). oridonin combined with gemcitabine induced a higher percentage of apoptosis in pancreatic cancer cells than that of oridonin or gemcitabine alone（P <0.05）.Moreover, the expressions of NF-κB and XIAP mRNA in pancreatic carcinoma cells were obviously down-regulated in combination group（P <0.05）. Conclusion: Oridonin can potentiate the antitumor effect of gemcitabine on pancreatic cancer in vitro, which may be realized through the down-regulation of XIAP and induction of cell apoptosis.

Key words: Oridonin, Gemcitabine, Pancreatic cancer, Apoptosis, XIAP, NF-κB