TY - JOUR
T1 - Epothilone B confers radiation dose enhancement in DAB2IP gene knock-down radioresistant prostate cancer cells
AU - Kong, Zhaolu
AU - Raghavan, Pavithra
AU - Xie, Daxing
AU - Boike, Thomas
AU - Burma, Sandeep
AU - Chen, David
AU - Chakraborty, Arup
AU - Hsieh, Jer Tsong
AU - Saha, Debabrata
PY - 2010/11/4
Y1 - 2010/11/4
N2 - Purpose: In metastatic prostate cancer, DOC-2/DAB2 interactive protein (DAB2IP) is often downregulated and has been reported as a possible prognostic marker to predict the risk of aggressive prostate cancer (PCa). Our preliminary results show that DAB2IP-deficient PCa cells are radioresistant. In this study, we investigated the anticancer drug Epothilone B (EpoB) for the modulation of radiosensitivity in DAB2IP-deficient human PCa cells. Methods and Materials: We used a stable DAB2IP-knock down human PCa cell line, PC3 shDAB2IP, treated with EpoB, ionizing radiation (IR), or the combined treatment of EpoB and IR. The modulation of radiosensitivity was determined by surviving fraction, cell cycle distribution, apoptosis, and DNA double-strand break (DSB) repair. For in vivo studies, the PC3shDAB2IP xenograft model was used in athymic nude mice. Results: Treatment with EpoB at IC50 dose (33.3 nM) increased cellular radiosensitivity in the DAB2IP-deficient cell line with a dose enhancement ratio of 2.36. EpoB delayed the DSB repair kinetics after IR and augmented the induction of apoptosis in irradiated cells after G2/M arrest. Combined treatment of EpoB and radiation enhanced tumor growth delay with an enhancement factor of 1.2. Conclusions: We have demonstrated a significant radiation dose enhancement using EpoB in DAB2IP-deficient prostate cancer cells. This radiosensitization can be attributed to delayed DSB repair, prolonged G2 block, and increased apoptosis in cells entering the cell cycle after G2/M arrest.
AB - Purpose: In metastatic prostate cancer, DOC-2/DAB2 interactive protein (DAB2IP) is often downregulated and has been reported as a possible prognostic marker to predict the risk of aggressive prostate cancer (PCa). Our preliminary results show that DAB2IP-deficient PCa cells are radioresistant. In this study, we investigated the anticancer drug Epothilone B (EpoB) for the modulation of radiosensitivity in DAB2IP-deficient human PCa cells. Methods and Materials: We used a stable DAB2IP-knock down human PCa cell line, PC3 shDAB2IP, treated with EpoB, ionizing radiation (IR), or the combined treatment of EpoB and IR. The modulation of radiosensitivity was determined by surviving fraction, cell cycle distribution, apoptosis, and DNA double-strand break (DSB) repair. For in vivo studies, the PC3shDAB2IP xenograft model was used in athymic nude mice. Results: Treatment with EpoB at IC50 dose (33.3 nM) increased cellular radiosensitivity in the DAB2IP-deficient cell line with a dose enhancement ratio of 2.36. EpoB delayed the DSB repair kinetics after IR and augmented the induction of apoptosis in irradiated cells after G2/M arrest. Combined treatment of EpoB and radiation enhanced tumor growth delay with an enhancement factor of 1.2. Conclusions: We have demonstrated a significant radiation dose enhancement using EpoB in DAB2IP-deficient prostate cancer cells. This radiosensitization can be attributed to delayed DSB repair, prolonged G2 block, and increased apoptosis in cells entering the cell cycle after G2/M arrest.
KW - Apoptosis
KW - Cell cycle check points
KW - DNA Repair
KW - Prostate cancer
KW - Radiosensitization
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U2 - 10.1016/j.ijrobp.2010.06.019
DO - 10.1016/j.ijrobp.2010.06.019
M3 - Article
C2 - 20970033
AN - SCOPUS:77958510735
SN - 0360-3016
VL - 78
SP - 1210
EP - 1218
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 4
ER -