Experimental Oncology, 2013, № 1

Nitric oxide coordinates development of genomic instability in realization of combined effect with ionizing radiation

Tue, 01 Jan 2013 00:00:00 GMT

Nitric oxide coordinates development of genomic instability in realization of combined effect with ionizing radiation Mikhailenko, V.M.; Diomina, E.A.; Muzalov, I.I.; Gerashchenko, B.I. The aim of this study was to investigate the ability of environmental nitrogen oxides or natural nitric oxide (NO) donors to modify free radicals balance and development of genomic instability alone or in combination with ionizing radiation. Methods: Genotoxicity and cytogenetic abnormalities were assessed in vitro in peripheral blood lymphocytes (PBL) isolated from healthy humans or in vivo in rats PBL. Human PBL were treated with physiologically relevant NO donor — S-Nitrosoglutathione and X-ray irradiation. The inhalation treatment of animals with NO was carried out in chamber with purified gaseous NO mixed inside with air. Levels of S-Nitrosohemoglobin and methemoglobin in the blood were assessed with electron paramagnetic resonance. The total level of reactive oxygen and nitrogen species in PBL was determined fluorometrically, and serum levels of reactive oxygen species was determined by spectrophotometric assay. DNA damages were assessed by alkaline single-cell gel electrophoresis. The frequency of chromosomal aberrations in human PBL measured with the conventional cytogenetic assay in metaphase cells on short-term (52 h) and long-term (72 h) cultures. Results: Environmental nitrogen oxides or release of NO from stable complexes with biomolecules (such as S-Nitrosothiols) intensified generation of free radicals, DNA damage and development of genomic instability alone or in combination with ionizing radiation. Treatment of PBL by S-Nitrosoglutathione caused prevalent induction of chromatid type but irradiation — chromosome aberrations. The dose dependence of chromatid-type aberrations observed in human PBL after combined influence of S-Nitrosoglutathione and ionizing radiation indicates a crucial role of NO in the formation of chromosomal instability. Conclusion: NO can deregulate free radicals balance resulted in genotoxic effect, posttranslational modification of repair enzymes and thus coordinated development of genomic instability and increase of cancer risk.

Search for potential gastric cancer markers using miRNA databases and gene expression analysis

Tue, 01 Jan 2013 00:00:00 GMT

Search for potential gastric cancer markers using miRNA databases and gene expression analysis Volkomorov, V.; Grigoryeva, E.; Krasnov, G.; Litviakov, N.; Tsyganov, M.; Karbyshev, M.; Zavyalova, M.; Afanasyev, S.; Cherdyntseva, N.; Lisitsyn, N.; Beresten, S. Aim: The aim of this study was to identify genes that are differentially expressed in gastric tumors and to analyze the association of their expression level with tumor clinicopathologic features. Methods: In the present research, we used bioinformatic-driven search to identify miRNA that are down-regulated in gastric tumors and to find their potential targets. Then, the expression levels of some of the target mRNAs were investigated using reverse transcription polymerase chain reaction (RT-PCR) analysis. Results: As a result of the bioinformatics analysis, fifteen genes were found to be potentially differentially expressed between the tumors and normal gastric tissue. Five of them were chosen for the further analysis (WNT4, FGF12, EFEMP1, CTGF, and HSPG2) due to their important role in cell proliferation and differentiation. Expression levels of these genes were evaluated in our collection of frozen tissue samples of gastric tumor and paired normal stomach epithelia. Increased FGF12 expression was observed in diffuse type of gastric cancer while WNT4 mRNA was found to be down-regulated in intestinal type of gastric cancer. Besides, CTGF gene overexpression was revealed in diffuse type of stomach cancer in comparison with that in intestinal type. Up-regulation of CTGF was also associated with lymph node metastasis. Conclusions: The findings show its expedient to perform further investigations in order to clarify diagnostic and prognostic value of CTGF, FGF12, and WNT4’s in stomach cancer as well as the role of these genes in carcinogenesis.

Influence of polychemotherapy on the morphology of metastases and kidney of resistant RLS-bearing mice

Tue, 01 Jan 2013 00:00:00 GMT

Influence of polychemotherapy on the morphology of metastases and kidney of resistant RLS-bearing mice Zonov, E.V.; Voronina, E.I.; Zenkova, M.A.; Ageeva, T.A.; Ryabchikova, E.I. Aim: Polychemotherapy (PCT), widely used for the antitumor treatment has a pronounced toxic effect on the organism, and its cytostatic effect sometimes is canceled by multidrug resistance of a neoplasia. Comprehension of the nature and development of pathological changes caused by the PCT during the treatment of cancer is very important to improve the efficiency of the therapy and to clarify the mechanisms of tumor-host interactions. This study was aimed to examine PCT impact on kidney cells and tissues in mice with transplanted resistant lymphosacroma (RLS) and to analyze morphology of metastases of the tumor in kidney during PCT. Materials and Methods: Male mice CBA/LacSto (55 animals) were intramuscularly implanted in the right hind paw by 105 cells/ml of tumor RLS (a diffuse large B-cell lymphosarcoma) with multi-drug resistance (MDR) phenotype. Mice received combination of cyclophosphamide (50 mg/kg), oncovin (0.1 mg/kg), hydroxydaunorubicin (4 mg/kg), and prednisone (5 mg/kg) accordingly to CHOP scheme each 7 days after inoculation of the tumor. The kidneys were sampled on days 1, 3 and 7 after each series of injection of PCT preparations and processed for light and electron microscopy, immunohistochemical analysis of Ki-67 and Apaf-1 proteins also was performed. Results: Tumor RLS produced metastases comprised of small cells in the kidneys of mice after 8 days post inoculation. Application of PCT resulted in destruction of small-cell metastases and development of many large-cell metastases in kidney. Application of PCT induced the development of prominent damage of nephron cells, primarily in S3 segments of proximal tubules. Even one series of PCT caused reduction of basal plasma folds in these cells and alteration of mitochondria. Damage of proximal tubules and involvement of distal tubules, renal bodies and interstitial tissue in the pathologic process, increased during the experiment. This work presents the description of morphological changes in kidney as well as of the tumor metastases under PCT influence. Conclusion: The obtained data should be considered while designing of remedies for recovery of internal organs functions after antitumor PCT.

Activity of thymidilate «salvage pathway» enzymes in human gastric cancer and blood serum: correlation with treatment modalities

Tue, 01 Jan 2013 00:00:00 GMT

Activity of thymidilate «salvage pathway» enzymes in human gastric cancer and blood serum: correlation with treatment modalities Borzenko, B.G.; Bakurova, E.M.; Popovich, Yu.A.; Sidyuk, E.A.; Popovich, A.Y. A comparative study of enzyme activity features of thymidilate “salvage pathway” synthesis in blood serum and tissues of different age patients with gastric cancer (T3–4N0-xM0) was carried out. Aim: To evaluate the diagnostic relevance of thymidilate metabolism enzymes activities and their association with tumor growth. Methods: Enzymes activities were determined by the radioisotope method and spectrophotometrically in tumor tissues and blood serum of 74 patients. Results: It was demonstrated that thymidine phosphorylase activity in gastric tumors is lower by 2.6 times as compared to non-neoplastic mucosa of resection margin. This being accompanied by decrease of its activity in the blood serum (from 47.9 ± 2.6 to 14.65 ± 2.4 nmol/min·mg, p < 0.001). An increase of thymidine kinase activity was revealed both in tumor tissues (more than 3.5 times) and in blood serum (from 3.9 ± 0,7 nmol/mg·h, to 6.8 ± 1.0 nmol/mg·h, p < 0.01). Changes in their activity in the postoperative period depended on the type of surgical procedure and tumor eradication. Conclusion: It could be suggested that control of individual dynamics of the enzymes activities in blood serum may be used as informative tool for monitoring of patients and treatment optimization.