Abstract: Abstract:Objective
To observe the expressions of nuclear factor E2-related factor 2(Nrf2) and NADPH quinine oxidoreductase(NQO1) in gastric cancer stem cells and normal gastric mucosa tissue,and to investigate the mechanism of Nrf2/NQO1 signal pathway in oxidative stress  of  gastric cancer stem cells.Methods Tumor spheroids suspended separation method was used to select stem cells in 60 gastric cancer tissue specimens. The stem cells were randomly divided into stem cells early group and activiated group. 30 cases of  normal gastric  mucosa tissues were regarded as normal control group. Western blotting method was applied to detect the expressions of Nrf2 and NQO1 protein in various groups. The activities of superoxide dismutase(SOD) and malondialdehyde(MDA) were observed. Results Compared with normal control group,the expression levels of Nrf2 and NQO1  in stem cells early group and activated group were increased(P<0.05),and the activity of SOD was decreased while the activity of MDA was increased significantly(P<0.05). Compared with  stem cells early group,the expression levels  of Nrf2 and  NQO1 in activated group were remarkably increased(P<0.05),and the activity of SOD was increased while the activity of MDA was decreased significantly(P<0.05). Conclusion Activating Nrf2/NQO1 signal pathway can adjust the activities of SOD and MDA in gastric mucosa tissue to enhance the tolerance of gastric mucosal cells against oxidative stress in order to protect the cells.

Key words: Nrf2/NQO1 signal pathway, oxidative stress, gastric cancer stem cells, superoxide dismutase, malondialdehyde