Effect of a novel thiazole derivative and its complex with polymeric carriers on the activity of antioxidant enzymes in murine lymphoma cells

Background. Previous studies have shown a pronounced cytotoxic effect of thiazole derivatives in combination with polymeric carriers on tumor cells. At the same time, the derivatives were not cytotoxic against non-cancerous cells in vitro. It was shown that thiazole derivatives at concentrations of 10 and 50 μM affected the prooxidant and antioxidant systems of lymphoma cells in vitro. The aim of this work was to study the effect of the complex of thiazole derivative N-(5-benzyl-1,3-thiazol-2-yl)-3,5-dimethyl-1-benzofuran-2-carboxamide (BF1) in combination with polymeric carriers poly(VEP-co-GMA)-graft-mPEG (Th1), poly(PEGMA) (Th3) and poly(PEGMA-co-DMM) (Th5) on the antioxidant defense system of the NK/Ly cell in vitro. Materials and Methods. The experiments were performed on white wild-type male mice with grafted NK/Ly lymphoma. Tumor cells were inoculated into mice intraperitoneally. Ascites was drained from the abdominal cavity of anaesthetized mice with a sterile syringe on the 7th-10th day after inoculation. Investigated compounds BF1, BF1 + Th1 (Th2, Th12), BF1 + Th3 (Th4, Th14), BF1 + Th5 (Th6, Th16) at a final concentration of 10 μM were added to the lymphoma samples and incubated for 10 min; the activity of antioxidant enzymes was determined according to the techniques described previously. Results. It was found that all the studied complexes based on thiazole derivative BF1 and polymeric carriers poly (VEP-co-GMA)-graft-mPEG (Th2, Th12), poly (PEGMA) (Th4, Th14) and poly (PEGMA-co-DMM) (Th6, Th16) at a concentration of 10 μm increased the activity of SOD, while the activity of CAT and GPX were reduced compared to control. Complexes Th2, Th12 and Th4 increased the significance of the BF1 influence on lymphoma cells from P <0.05 to P <0.01. Pure polymeric carriers did not affect the level of the antioxidant defense system enzymes. Conclusions. Thus, it was found that the polymeric carriers in combination with thiazole derivative BF1 increased the significance of thiazole derivative BF1 influence on the activity of the antioxidant defense system of lymphoma cells, while pure polymeric carriers did not affect the activity of SOD, CAT or GPX. The results of this work can be used for further studies of complexes of thiazole derivative and PEG-containing polymeric carriers as potential antitumor drugs.

Effect of thiazole derivative complexed with nanoscale polymeric carriers on cellular ultrastructure of murine lymphoma cells in vivo

Background. A pronounced cytotoxic action of the thiazole derivatives complexed with polymeric carriers on tumor cells in vitro was reported earlier, while no cytotoxicity of these compounds was detected toward noncancerous cells. It was found that thiazole derivatives at concentrations of 10 and 50 µM affected lymphoma cell ultrastructure in vitro. The purpose of this work was to investigate the effect of thiazole derivative 8-methyl-2-Me-7-[trifluoromethyl-phenylmethyl]-pyrazolo-[4,3-e]-[1,3]- thiazolo-[3,2-a]-pyrimidin-4(2H)-one (PP2) and its complexes with polymeric carriers poly(VEP-co-GMA)-graft-mPEG (Th12) and poly(PEGMA) (Th14) on the ultrastructure of lymphoma cells in vivo. Materials and Methods. Experiments were conducted on white wild-type male mice with grafted NK/Ly lymphoma. Ascite tumors were created by intreperitoneal inocu­lation of 1–2 mln of Nemet–Kelner lymphoma cells to mice. On the 12th day after inoculation, the body weight of animals was increased by 140–160 % mostly due to ascites growth. For treatment of ascites three solutions of the chemical compounds were prepared: PP2, PP2 + Th12, PP2 + Th14 and administered to the mice intraperitoneally for 5 days. The final concentration of PP2 was 5 mg/kg of body weight. Abdominal drainage from ascites was performed with a sterile syringe under chloroform anesthesia on the 10th day after the start of treatment. The ultrastructure of the cells was examined by electron microscopy. Results. Еlectron microscopy study showed that control lymphoma cells have a special subcellular formations such as a relatively large nucleus, and specific plasma membrane filaments. The effects of thiazole derivative revealed apoptotic and necrotic manifestations of cytotoxicity, such as a deformation and disintegration of nucleus, a decreased nucleus/cytoplasm ratio, a destruction of the plasma membrane and a change of mitochondria shape. The studied compound complexed with polymeric carriers caused an apoptotic-like changes in lymphoma cells. Under the action of such complexes, the nucleus/cytoplasm ratio decreased and the area of mitochondria increased. Conclusions. The obtained results suggest that the tested compounds induce apoptosis in tumor cells. Complexes of thiazole derivative with polymers do not impair the effect of the compound on lymphoma cells. The obtained data can be used to carry out further preclinical studies of thiazole derivatives complexed with polymeric carriers as potential antitumor drugs.

Prooxidant and antioxidant processes in lymphoma cells under the action of pyrazolopyrimidine derivative

Background. The influence in vitro of thiazole derivative 8-methyl-2-Me-7-[trifluoro­methyl-phenylmethyl]-pyrazolo-[4,3-e]-[1,3]-thiazolo-[3,2-a]-pyrimidin-4(2H)-one (PP2) on the level of lipid peroxidation products, superoxide anion radical and antioxidant system activity in lymphoma cells was studied. A pronounced cytotoxic action of the thiazole derivative on the tumor cells in vitro was reported earlier, however, no cytotoxicity of this substance was detected toward non-cancerous cells. In addition, it was shown that the sca­vengers of active forms of Oxygen significantly reduced the cytotoxic effect of the studied compound. The purpose of this work was to investigate the effect of 8-methyl-2-Me-7-[trifluoromethyl-phenylmethyl]-pyrazolo-[4,3-e]-[1,3]-thiazolo-[3,2-a]-pyrimidin-4(2H)-one on the content of lipid peroxidation products, superoxide radical and the activity of enzymes of antioxidant defense in the lymphoma cells. Materials and Methods. Experiments were conducted on white wild-type male mice with grafted NK/Ly lymphoma. Ascites tumor cells were passaged by the intreperitoneal inoculation to mice. Abdominal drainage with ascites was performed with a sterile syringe under ether anesthesia. PP2 was dissolved in dimethylsulfoxide. The product content and enzymatic activity were determined spectrophotometrically. Statistical analysis of obtained results was carried out using MS Excel-2013 program. Results. The influence of the pyrazolopyrimidine derivative on the content of lipid peroxidation products and superoxide radical in lymphoma cells was investigated. It was found that the studied compound did not change the amount of the primary lipid peroxidation products, but reduced the amount of secondary products. A decrease in the MDA content under the action of the studied derivative indicates probable interaction of the substance with the reactive Oxygen species. Pyrazolopyrimidine derivative did not change the level of the superoxide radical. The effect of the thiazole derivative on the activity of key enzymes of the antioxidant system in lymphoma cells was investigated. The studied compound at the concentration of 10 µM activated superoxide dismutase. Pyrazolopyrimidine derivative decreased the activity of catalase and glutathione peroxidase. Such changes in the activity of enzymes can cause the growth of hydrogen peroxide in the cell, which is toxic in large quantities. Conclusions. The obtained results may indicate that the studied pyrazolopyrimidine derivative can realize its cytotoxic effect on lymphoma cells though the action on the pro­ducts of lipid peroxidation and antioxidant system activity. These data can be used to understand the mechanism of action of the studied compounds and for further improvement of their antitumor effect. Keywords: lymphoma, pyrazolopyrimidine derivative, lipid peroxidation, antioxidant system, antitumor drugs