Cell death in irradiated prostate cancer cells assessed by flow cytometry

Despite the significant advances in cancer chemotherapy, radiotherapy still remains a method of choice for treatment of metastatic human prostate cancer. This study presents quantitative analysis of 60Co gamma-radiation effects on cell growth and cell death of metastatic human prostate cancer PC-3 cell line, performed in time (24-72h) and dose (2-20 Gy) dependent manner. The irradiated PC-3 cells were mostly dying by necrosis at late time intervals (72h), while apoptotic cell death was negligible. The EC50 or 50% of cytotoxicity was not achieved within the radiation doses used (2-20 Gy), but significant cell growth inhibition with IC50 of 10.4 Gy was observed. It is concluded that the increase in the radiation dose may have an important cytostatic effect, but for the complete eradication of metastatic prostate cancer novel cytotoxic drugs and radiosensitizers should be introduced as adjuvant.