THE EFFECT OF SILENCING THE Tip60 GENE ON THE RESPONSE TO RADIOTHERAPY IN BREAST CANCER CELLS

One of the most important problems encountered in patients with triple-negative breast cancer (BC) treatment is the inadequate response of tumor tissue to treatment. The high expression of the Tip60, which is involved in the repair of DNA double-strand breaks, will increase the repair of DNA damage to be created in tumor cells, especially during the radiotherapy treatment process, thus reducing the treatment response and having a negative effect. In this study, the Tip60 gene was silenced using siRNA in MCF-7 and MDA-MB-231 cell lines, and their response to radiotherapy was monitored. To determine whether gene silencing was successful or not, Tip60 mRNA and protein expression values were measured. Cytotoxicity and DNA damage in UV-treated cells were analyzed by MTT and COMET methods, respectively. According to the results of the study, more DNA damage was observed in the MCF-7 in which the Tip60 gene was silenced and UV-treated compared to the non-Tip60 gene-silenced and UV-treated cells. On the other hand, more DNA damage was observed in the MDA-MB-321 in which the Tip60 gene was non-silenced and applied UV, compared to the cells in which the Tip60 gene was silenced. However, excessive DNA damage was already observed in the untreated MDA-MB-231. According to the results, silencing of the TiP60 gene in the MCF-7 may be beneficial in reducing resistance to radiotherapy, but no effect is expected in the MDA-MB-231. This can be explained by the fact that they are heterogeneous tumors. These data could use for future treatment development studies

Evaluation of allantoin levels as a new marker of oxidative stress in Behcet's disease

The increased production of reactive oxygen species (ROS) from activated neutrophils in Behcet's disease ( BD) and recurrent aphthous stomatitis (RAS) may result in increased oxidative stress. Uric acid can react rapidly with neutrophil-derived ROS to form allantoin. The purpose of the study was to evaluate the serum levels of allantoin as a new marker of oxidative stress in BD compared with malondialdehyde (MDA) levels as a well-known marker. Blood samples were obtained from 23 BD patients, 22 RAS patients as positive controls, and 21 healthy controls. When compared to the healthy controls, we found higher allantoin and MDA levels in the BD patients and higher MDA levels in the RAS patients. Serum ascorbic acid levels in the BD patients were significantly lower than in the controls. Increased allantoin and MDA levels suggest the possible involvement of free radicals in BD. As allantoin is only a product of uric acid oxidation by reactive oxygen and nitrogen species, it may also be used as a marker of oxidative stress in BD

Correlation Between Gamma-Glutamyl Transferase Activity and Glutathione Levels in Molecular Subgroups of Breast Cancer.

The gamma-glutamyl cycle catalyzed by gamma-glutamyl transferase (GGT) plays an important role in glutathione (GSH) homeostasis in the cell. In cells continuously exposed to the drug, the main phase of the enzymatic detoxification is the conjugation of the drug with GSH catalyzed by glutathione-S-transferase (GST). Conjugation of drugs with GSH is the first step in the development of chemotherapeutic drug resistance. In this study, we aimed to investigate the relationship between GGT and GSH in molecular subgroups of breast cancer patients

Normal and Tumour Tissue mRNA Expressions of Telomerase Complex Genes in Several Types of Cancer.

To investigate the changes in mRNA expression levels of telomerase-related significant proteins in several types of cancer

Normal and Tumour Tissue mRNA Expressions of Telomerase Complex Genes in Several Types of Cancer

Aims: To investigate the changes in mRNA expression levels of telomerase-related significant proteins in several types of cancer. Methods: Human telomerase reverse transcriptase, pontin, reptin and dyskerin expressions were measured in normal and tumour tissues obtained from 26 patients with colorectal, breast and gastric cancers, using the real-time reverse transcriptase-polymerase chain reaction method. Results: For all patients, no significant difference was found in mRNA expressions of human telomerase reverse transcriptase and dyskerin (p>0.05), although their levels in tumour tissues were found to be higher than in normal tissues. However, pontin and reptin mRNA expressions were significantly higher in tumour tissues than in normal tissues (p<0.01). While human telomerase reverse transcriptase showed a high correlation with only pontin (p<0.001) in normal tissues, high positive correlations were observed between human telomerase reverse transcriptase with pontin (p<0.005), reptin (p<0.01) and dyskerin (p<0.01) in tumour tissues. Conclusion: The increased mRNA expressions of all four genes in tumour tissues may suggest a role in cancer development. Correlations of pontin, reptin and dyskerin with human telomerase reverse transcriptase support the hypotheses describing their roles in telomerase complexe