Selection of Reliable Reference Genes for Gene Expression Studies in Human Epidermoid Carcinoma A431 Cells Exposed to Corpuscular Ionizing Irradiation of Varying Dose Rate

Radiation therapy is a fundamental part of the treatment of many oncological diseases. It is used both as a primary treatment modality and adjunct to other treatment approaches, with therapeutic intent ranging from curative to palliative interventions. Different dose rates exert differential biological effects in the cells - a phenomenon known as the dose-rate effect. For example, the severity of DNA damage, cell cycle progression and cellular senescence was strongly influenced by the dose rate of corpuscular radiation. Valuable insights into the mechanisms underlying tumor cell responses to ionizing radiation can be gained by analyzing changes in the expression of genes involved in radiation-induced cellular reactions using standardized real-time quantitative polymerase chain reaction (qPCR). However, accurate interpretation of qPCR data is often complicated by challenges in selecting appropriate reference genes for normalization. The effects of ionizing irradiation in this case introduce more unpredictable, due to variability in both the extent and the nature of damage. These variations can result in delays or even arrest of the cell cycle, subsequently leading to pronounced alterations in the expression profiles of numerous cellular proteins, including the housekeeping genes. This study aimed to determine the reliable reference genes for assessment of gene expression changes in tumor cells exposed to high-dose rate and low-dose rate irradiation. We found differences in the stability of expression of traditionally used housekeeping genes depending on the irradiation dose rate.