Positive and negative role of oxidative stress in the prognosis of patients with gastric cancer.

M. Kędzierska, J. Kolodziejczyk-Czepas, J. Jakubik, J. Piekarski, A. Jeziorski, P. Nowak, P. Potemski (Lodz, Poland)

Late-breaking posters
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: Gastric cancer is the second leading cause of cancer-related deaths worldwide. Reactive oxygen species (ROS) production in cancer cells is one of the mechanisms underlying synergetic cytotoxicity seen with combination anti-tumor treatments. Compared to normal cells, cancer cells have intrinsically higher levels of ROS and are under oxidative stress due to an imbalanced redox status. Targeting ROS is an important therapeutic strategy for cancer as exemplified by cancer drugs, which induce ROS-dependent synergistic cytotoxicity in gastric cancer cells. The present study was designed to asses the level of selected oxidative stress biomarkers in blood plasma derived from gastric cancer patients.

Methods: Detection of nitrotyrosine-containing blood plasma was performed by a competitive ELISA method, using the OxiSelect™ Nitrotyrosine ELISA Kit. The non-enzymatic antioxidant capacity (NEAC) of blood plasma samples was estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) reduction assay. The amount of free thiol groups was estimated with 5,5′-dithiobis(2-nitro-benzoic acid). Blood samples were taken from 32 healthy volunteers and 50 patients with gastric cancer who were hospitalized in the Department of Oncological Surgery, Medical University of Lodz, Poland.

Results: Our other studies have demonstrated that the concentration of thiol grups in plasma proteins from metastatic gastric cancer patients differs from the concentration of thiol groups in plasma proteins obtained from healthy volunteers (p<0,05). The concentration of 3-nitrotyrosine of plasma proteins from invasive gastic cancer was significantly higher than in plasma proteins obtained from healthy volunteers (p<0,001). The concentration NEAC of blood plasma from patients with gastic breast cancer was decreased compared with the healthy subject group (p<0,005).

Conclusion: The present investigation was designed to evaluate oxidative stress markers in patients with confirmed gastric cancer. Oxidative stress was monitored in blood serum by determination of protein 3-nitrotyrosine. The intensity of oxidative stress may undergo many fluctuations both during the progression of malignancy and in cancer therapy. Low levels of ROS play an important role in proliferation of tumor cells, angiogenesis and metastasis, however the generation of high levels of various oxidants, results in oxidative stress that may induce cell death.