TY - JOUR T1 - Low Production of Reactive Oxygen Species and High DNA Repair: Mechanism of Radioresistance of Prostate Cancer Stem Cells JF - Anticancer Research JO - Anticancer Res SP - 4469 LP - 4474 VL - 33 IS - 10 AU - YOUNG SEOK KIM AU - MUN JUNG KANG AU - YONG MEE CHO Y1 - 2013/10/01 UR - http://ar.iiarjournals.org/content/33/10/4469.abstract N2 - Background: Cancer stem cells (CSCs) are resistant to radiotherapy and are responsible for tumor recurrence of various malignant tumors, including prostate cancer. Materials and Methods: In order to define the radioresistance mechanism of prostate CSCs, their proliferative activity, cell cycle distribution, expression of CD133 stem cell marker, reactive oxygen species (ROS) production, and DNA repair efficiency were examined using prostatospheres and adherent LNCaP cells as a model of prostate CSC and bulk model of differentiated cells, respectively. Results: Compared to adherent cells, prostatospheres exhibited greater number of low-to-intermediate ROS-producing cells and CD133-positive cells. Prostatospheres showed higher expression of DNA repair proteins after ionizing radiation (IR). Conclusion: Low vulnerability to ROS-induced cellular damage and the efficient repair of IR-induced DNA injury may explain the radioresistance of prostate CSCs. Therefore, increasing ROS-induced cytotoxicity and inhibition of DNA repair in prostate CSCs may help achieve complete eradication of prostate CSCs by radiotherapy. ER -