Expression And Significance Of COX-2,Snail And E-cadherin In Gastric Cancer

Objective:To investigate the mRNA and protein expressions of COX-2, Snail and E-cadherin in gastric cancer tissues and the relationship with clinicopathologic features and helicobacter pylori infection in order to explore the possible molecular mechanism of gastric carcinogenesis.Methods:Sixty gastric cancer tissues and corresponding adjacent tissues were identified as experiment groups. The expressions of COX-2, Snail and E-cadherin were tested by Real-time fluorescence quantitative PCR, immunohistochemistry and western blot. Helicobacter pylori infection was tested by Warthin-Starry silver stain. We further analysis the relationship between the expressions of COX-2, Snail and E-cadherin and clinicopathology and helicobacter pylori infection.Results: (1) The mRNA expressions of COX-2, Snail and E-cadherin in gastric cancer tissues are 8.88±4.58,5.27±2.86 and 0.71±0.44 respectively, which are significantly different from those in adjacent gastric cancer tissues(3.65±1.92,3.89±2.04 and 1.13±0.73 respectively, P<0.05) and in normal gastric tissues(P<0.05). The protein expressions of COX-2, Snail and E-cadherin by immunohistochemistry in gastric cancer tissues are 60.0%,53.3% and 33.3% respectively, which are significantly different from those in adjacent gastric cancer tissues (35%,26.7% and 70.0% respectively, P<0.05) and in normal gastric tissues(0%,5% and 80% respectively, P<0.05). The protein expressions of COX-2, Snail and E-cadherin by western blot in gastric cancer tissues are 0.59±0.32,0.14±0.08 and 1.25±0.63 respectively, which are significantly different from those in adjacent gastric cancer tissues(0.25±0.10,0.09±0.03 and 2.92±1.24 respectively, P<0.05) and in normal gastric tissues (0.00±0.00,0.04±0.02 and 2.99±0.86 respectively, P<0.05).Significant differences of COX-2 and Snail expressions were found between adjacent gastric cancer tissues and normal tissues (P<0.05). But no significant differences of E-cadherin was found between adjacent gastric cancer tissues and normal tissues (P>0.05). (2) Positive correlation was shown between COX-2 and Snail. Negative correlation was shown between Snail and E-cadherin or COX-2 and E-cadherin. No correlation was shown between the expressions of them and helicobacter pylori infection. (3) The abnormal expressions of COX-2, Snail and E-cadherin were significantly correlated with tumor differentiation status and depth of invasion of gastric cancer (P<0.005). But the expressions of them are not correlated with sex, age, carcinoma diameter, location and lymph node metastasis (P>0.05).Conclusion:(1) The mRNA and protein expression of COX-2, Snail are highly expressed and E-cadhern is lowely expressed in gastric cancer. The abnormal expressions of COX-2, Snail and E-cadherin are correlated with tumor differentiation status and depth of invasion. But they are not correlated with helicobacter pylori infection. (2) COX-2 may regulat E-cadherin expression via up-regulating Snail.