AIM: To investigate the changes of the redox status and the antioxidative capability in the tissue of malignant tumors. METHODS: The carcinoma tissues collected from 42 patients with primary cancer in digestive tract (13 cases of esophageal cancer, 14 cases of gastric cancer and 15 cases of colorectal cancer),the corresponding paratumor mucosa tissues were taken as the control samples. The content of oxidized and reduced glutathion (GSSG and GSH), oxidized and reduced coenzyme II (NADP+ and NADPH) were measured, the GSH/GSSG, NADPH/NADP+ ratios, and the GSH/GSSG, NADPH/NADP+ redox potentials were calculated according to Nernst formula. RESULTS: The levels of GSH and NADPH in cancer tissues were significantly higher than those in corresponding paratumor tissues (P0.05). CONCLUSIONS: The significant increase in GSH and NADPH contents in cancer tissues indicates a notable enhancement of its antioxidative capability compared with the corresponding paratumor tissues. Based on this changes, the redox potential in the cancer tissues has only slightly reductive shift, which may suggest an apparent oxidative stress existed in the cancer tissues.

Aim To investigate the role of K562 cells conditioned media on redox state of human umbilical vein endothelial cells (HUVECs) and the role of buthionine sulfoxine(BSO), a selective inhibitor of ?-glutamylcysteine synthetase, on HUVECs cultured with K562 cells conditioned media. Methods Glutathione(GSH)、oxidized glutathione (GSSG)、NADP~+、NADPH concentration and the viability of HUVECs under various conditions were determinated. Results GSSG、GSH、NADP~+、NADPH concentration of HUVECs increased when HUVECs were cultured with K562 cells conditioned media. The inhibition of HUVECs growth by Bso enhanced when K562 cells conditioned media were used at the same time. Conclusion Under the effection of chronic myelogenous leukemia cells conditioned media, endothelial cells may be more sensitive to BSO.