Evaluation of Oxidative Stress in Colorectal Cancer Patients

Objective To evaluate the oxidative stress in patients with colorectal cancer and to investigate the relationship between oxidative stress and colorectal cancer. Methods Seventy-six subjects were divided into two groups （36 colorectal cancer patients as the study group and 40 normal healthy individuals as the control group）. Their protein oxidation, DNA damage, lipid peroxidation and antioxidants, vitamin C, vitamin E, glutathione （GSH）, and antioxidative enzymes in serum were detected. Results The levels of protein carbonyl and advanced oxidation protein products （AOPP） were significantly higher in the study group than in the control group （P〈0.01）. Serum 8-OHdG was significantly increased in the study group compared to the control group （P〈0.01）. However, the mean serum level of MDA and conjugated diene was lower in the study group than in the control group （P〈0.01）. The activity of antioxidative enzymes was significantly decreased in the study group compared to the control group （P〈0.01）. Serum vitamins C and E concentrations were significantly reduced in the study group compared to the control group （P〈0.01）. Conclusion Colorectal cancer is associated with oxidative stress, and assessment of oxidative stress and given antioxidants is important for the treatment and prevention of colorectal cancer.

Effect of pseudolaric acid B on gastric cancer cells: Inhibition of proliferation and induction of apoptosis

AIM: To examine the effect of pseudolaric acid B on the growth of human gastric cancer cell line, AGS, and its possible mechanism of action.METHODS: Growth inhibition by pseudolaric acid B was analyzed using MTT assay. Apoptotic cells were detected using Hoechst 33258 staining, and confirmed by DNA fragmentation analysis. Western blot was used to detect the expression of apoptosis-regulated gene Bcl-2, caspase 3, and cleavage of poly (ADP-ribose)polymerase-1 (PARP-1).RESULTS: Pseudolaric acid B inhibited the growth of AGS cells in a time- and dose-dependent manner by arresting the cells at G2/M phase, which was accompanied with a decrease in the levels of cdc2.AGS cells treated with pseudolaric acid B showed typical characteristics of apoptosis including chromatin condensation and DNA fragmentation. Moreover,treatment of AGS cells with pseudolaric acid B was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of PARP-1.CONCLUSION: Pseudolaric acid B can dramatically suppress the AGS cell growth by inducing apoptosis after G2/M phase arrest. These findings are consistent with the possibility that G2/M phase arrest is mediated by the down-regulation of cdc2 levels. The data also suggest that pseudolaric acid B can trigger apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease.

Serum Helicobacter pylori Kat A and Ahp C antibodies as novel biomarkers for gastric cancer

AIM: To investigate catalase (KatA) and alkyl hydroperoxide reductase (AhpC) antibodies of Helicobacter pylori as biomarkers for gastric cancer (GC). METHODS: This study included 232 cases and 264 controls. Recombinant KatA and AhpC proteins were constructed and the levels of antibodies were tested by indirect enzyme-linked immunosorbent assay (ELISA). Logistic regression was applied to analyze the relationships between KatA, AhpC and GC. The chi(2) trend test was used to evaluate the dose-response relationships between serum KatA and AhpC antibody levels and GC. Receiver operating characteristic (ROC) curve was used to evaluate the screening accuracy of KatA and AhpC as biomarkers. Combined analysis was used to observe screening accuracy of predictors for GC. RESULTS: In all subjects, the association between KatA and AhpC and GC risk was significant (P < 0.001) with odds ratio (OR) = 12.84 (95%CI: 7.79-21.15) and OR = 2.4 (95%CI: 1.55-3.73), respectively. KatA and AhpC antibody levels were strongly related to GC risk with a dose-dependent effect (P for trend < 0.001). The area under the ROC (AUC) for KatA was 0.806, providing a sensitivity of 66.81% and specificity of 86.36%; and the AUC for AhpC was 0.615, with a sensitivity of 75.65% and specificity of 45.49%. The AUC was 0.906 for KatA and flagella protein A (FlaA) combined analysis. CONCLUSION: Serum KatA and AhpC antibodies are associated with GC risk and KatA may serve as a biomarker for GC. KatA/FlaA combined analysis improved screening accuracy.