Radiotherapy plays a significant role in brain cancer treatment; however, the use of this therapy is often accompanied by neurocognitive decline that is, at least partially, a consequence of radiation-induced damage to neural stem cell populations. Our findings describe features that define the response of neural stem cells (NSCs) to ionizing radiation. We investigated the effects of irradiation on neural stem cells isolated from the ventricular-subventricular zone of mouse brain and cultivated in vitro. Our findings describe the increased transcriptional activity of p53 targets and proliferative arrest after irradiation. Moreover, we show that most cells do not undergo apoptosis after irradiation but rather cease proliferation and start a differentiation program. Induction of differentiation and the demonstrated potential of irradiated cells to differentiate into neurons may represent a mechanism whereby damaged NSCs eliminate potentially hazardous cells and circumvent the debilitating consequences of cumulative DNA damage.

A comparison between breast cancer cell line MCF7 and human adipose-derived stem cells (ADSC) after irradiation by the same doses of megavoltage X-rays was performed. The cell growth, the induction of apoptosis and the expression of selected genes were analyzed. Irradiated MCF7 related to its control sample grows slower than ADSC and it undergoes apoptosis in much higher levels than ADSC. This was confirmed by real-time polymerase chain reaction as well, where the expression of apoptotic genes was found to be considerably higher for MCF7 than for ADSC. From the results of this project, it could be stated that MCF7 is more radiosensitive than ADSC.