Effect of chemical agents on cell cycle and investigation of molecular mechanisms

The tight cycle of the cell cycle is essential for the genome duplication and the correct separation of chromosomes. Damages in cyclin, cyclin-dependent kinases, cell cycle checkpoints and repair mechanisms involved in this process cause uncontrolled cell division in cells and cause cancer development. Lung cancer is one of the leading causes of cancer-dependent deaths in the world. Chemotherapy improves the recovery rates and quality of life of lung cancer patients. Platinum containing drugs are prefered in the treatment of many cancers. Antifolate derived drugs are often used in combination with platinum containing drugs in pleural mesothelioma and non-small cell lung cancer. The aim of this study was to investigate the effects of platinum derivative Cisplatin and antifolate derivative Pemtrex on lung cancer and normal cells on cell cycles. For this purpose, the toxicity caused by Cisplatin and Pemtrex separately and intermittently on A549 and BEAS-2B cells was investigated by MTT method. Cisplatin caused higher toxicity in BEAS-2B cells (p <0.01). When Pemtrex drug was applied alone, it was determined that BEAS-2B cells caused higher toxicity than the A549 cells in the 48 and 72 hours experimental groups (p <0.01). The toxicity in A549 cells was higher in BEAS-2B cells in experimental groups treated with Cisplatin and Pemtrex 24 hours later. The experimental groups in which Cisplatin was applied 24 hours after than Pemtrex, toxicity was detected in both cell lines. Morphological changes in the cells were determined by phase contrast microscopy. Activation of caspase 3, 7 and 9 was found to increase in A549 cells. The expression of the genes in the cell cycle at the molecular level was investigated by qRT-PCR method. Cyclin and cyclin-dependent kinase genes and DNA repair genes were downregulated in A549 cells and upregulated in BEAS-2B cells. As a result, it was determined that the highest toxicity on A549 cells occurred after Pemtrex after Cisplatin drugs. While creating toxicity on cancerous cells, the difference between gene expression levels in molecular analyzes with concentration that does not have toxic effects on normal cells will be the basis of other studies in this context.