Glutathione system in the blood of gastric cancer patients with various tumor histotypes and prevalence of the disease

e16534

Background: The role of oxidative stress in tumor growth and the multifaceted functional significance of glutathione have led to an interest in studying the components of the glutathione-dependent system in gastric cancer (GC), which occupies a leading position in cancer incidence and mortality. The aim of this work was to study the functioning of the glutathione system in the red blood cells of patients with gastric cancer in a comparative aspect depending on the histotype of the tumor and the prevalence of the disease. Methods: The study included 89 patients with GC divided into 6 groups depending on the histotype of the tumor. Separately, the results of the study were analyzed in patients with T4 status according to TNM and in patients with stage IV cancer. The content of reduced glutathione and the activity of glutathione-dependent enzymes were studied by conventional spectrophotometric methods in the red blood cells of patients. Statistical processing of the results was performed using the Statistika 6.0 program with Student’s t-test for two independent groups. Results: An increase in the content of glutathione in patients with GC compared with the group without oncopathology was revealed. The maximum increase was observed in patients with low-grade adenocarcinoma - by 42.5%, while in signet ring cell cancer (SRCC) there was only a tendency to increase by 17.8%. Glutathione reductase activity was reduced in adenocarcinoma by 23.4-26.2% and did not change in SRCC. The activity of the antioxidant enzymes glutathione peroxidase and glutathione transferase was increased in all groups and especially in SRCC - by 76% and 23-29%, respectively. In patients with T4 status and at stage 4 of the process, lower activity of the studied glutathione-dependent enzymes was revealed compared with all other groups of patients. Conclusions: The data indicate a greater functional potential of the glutathione system in SRCC. A significant increase in the activity of glutathione transferase with a sufficiently high level of reduced glutathione contributes to the development of treatment resistance in patients with SRCC.

[The activity of redox-regulatory systems in the primary and recurrence tumors in vulvar cancer]

The activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST), the content of reduced glutathione (GSH) and malondialdehyde (MDA) were investigated in the samples of the tumor, peritumoral zone and healthy tissue, taken at the line of resection, were obtained from 14 patients with primary squamous cell carcinoma of the vulva, and 13 patients with local recurrence appeared in the period from 3 months to 7 years. by conventional spectrophotometric methods. The content of GSH and the activity of SOD, GPx, GR, GST were significantly increased, while MDA was decreased in the tissue of the primary carcinoma of the vulva in compared with the healthy tissue. Differences in the functioning of the investigated system of enzymes in the peritumoral zone were also revealed in the primary and recurrent tumoral process. Similar but much less pronounced changes were also observed in the recurrent tumor. It is suggested that such dynamics of activity of the studied system with the progression of cancer process can be the result of adaptation to changes in the local biochemical status of healthy (nonmalignant) tissue of the organ carrying the tumor and reflect the metabolic features of the recurrent tumor.

Regulation of the oxidative processes as a possible mechanism of iron nanoparticles antitumor action

e23160

Background: It has been shown that metal nanoparticles (NPs) can inhibit a tumor growth. Oxidative processes play important roles in tumor development and growth. The aim of this study was to determine parameters of oxidative stress in the blood of tumor-bearing animals depending on the antitumor effect of iron NPs (30-50 nm). Methods: Male rats with transplantable lymphosarcoma (LS) in the main group (n = 21) were treated with eight i.p. injections of iron NPs (total doses of 10 mg/kg bw), the control LS rats (n = 20) received saline i.p. The activity of catalase, superoxide dismutase (SOD), content of glutathione (GSH) and malondialdehyde (MDA) in the red blood cells (RBC) and ceruloplasmin oxidase activity (CP) and MDA content in blood plasma were measured. These parameters were analyzed in rats with complete tumor regression (n = 12) after NPs treated and in cases of tumor growth (n = 9). Results: In RBC of control group the level of GSH and catalase activity were increased compared to healthy rats by 24% and 14.3% (p < 0.05), respectively. In spite of activation of the given antioxidant system components, the MDA content in RBC was increased by 45% (p < 0.01) compared to normal values. In plasma of control group we observed an increase in MDA by 167.4% (p < 0.01) and a decrease in CP by 36.8% (p < 0.001). In the main group there was a decrease in blood MDA level and the antioxidant system reorganization. The degree of changes depended on the antitumor effect of NPs: rats with tumor growth showed a tendency to the decreasing MDA in RBC and normalization of plasma MDA; MDA in rats with LS regression was similar to normal values. In the main group the CP activity did not differ from the values in healthy rats. GSH increased in animals with tumor growth by 218.6% and in the animals with the effect - by 69% compared to normal values (p < 0.01). SOD activity in the rats with LS growth increased by 42% and in the rats with LS regression it decreased by 30% (p < 0.01). Conclusions: The data suggest the relationship between antitumor effect and modulating action on oxidative processes in LS rats treated by iron NPs. Iron NPs improved efficiency of antioxidant system in blood and contributed to suppression of oxidative stress associated with tumor growth.

[Effect of iron nanoparticles on free radical oxidation process in blood of rats with Pliss lymphosarcoma]

The use of metal nanoparticles (NPs) for cancer treatment requires careful examination of their biological effects. The aim of this study was to determine parameters of oxidative processes in the blood of tumor-bearing animals treated with metallic iron NPs only. The markers of antioxidant status and accumulation of lipid peroxidation products were measured in erythrocytes and blood plasma of rats with Pliss lymphosarcoma (PLS) and intact rats. PLS animals were treated eight times with iron NPs (at a dose of 1.25 mg/kg bw (main group), rats of the control group received saline (0.3 ml). In control animals, an increase in malondialdehyde (MDA) was observed in red blood cells (RBC) by 45%; this was accompanied by compensatory increase in reduced glutathione (GSH) and catalase by 24% and 14.3%, respectively (p<0.05). In plasma an increase in MDA by 167.4% (p<0.01) and a decrease in oxidase activity of ceruloplasmin (CP) by 36.8% (p<0.001) were found. In the main group there was a decrease of accumulation of lipid peroxidation products in the blood. Intensity of detected changes depended on the antitumor effect: rats with growing LSP showed a tendency to the decrease in the RBC MDA level and normalization of plasma MDA; in animals with LSP regression this marker did not differ from normal values. In all animals of the main group the CP content was basically the same as in intact rats while GSH increased in the group without therapeutic effect (by 218.6%) and in the group with the effect by 69% (versus normal values; p<0.01). SOD activity in the rats with LSP growth significantly increased (by 42%), in the rats with regression decreased (by 30%) with subsequent normalization. Thus, administration of iron NPs caused activation of the antioxidant system in blood and a significant decrease in the manifestations of oxidative stress associated with tumor growth.