Schaefer Niklaus G, James Engles, Wahl Richard L
Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Sidney Kimmell Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-0817, USA.
Nucl Med Commun. 2011 Nov;32(11):1046-51. doi: 10.1097/MNM.0b013e32834a369b.
To assess the possible radiosensitizing capabilities of two different poly(ADP-ribose) polymerase (PARP) inhibitors in combination with external beam and I-tositumomab in a non-Hodgkin's lymphoma cell line.
Epstein-Barr virus-infected human Raji lymphoma cells with lentivirally transfected green fluorescent protein and luciferase in log-phase growth were incubated with various doses of AZD-2281 and ABT-888 24 h before external beam radiation exposure. A 500 nmol/l concentration of AZD-2281 and ABT-888 was used to assess the growth curve of Raji lymphoma cells over 5 days. The number of double-stranded breaks was visually assessed using a H2AX antibody and confocal microscopy. Intracellular PARP activity was measured 2 h after incubation with AZD-2281 (500 nmol/l) and ABT-888 using a colorimetric PARP assay kit. The radiosensitizing effect of AZD-2281 (500 nmol/l) with various doses of I-tositumomab was assessed after 24 h.
A volume of 500 nmol/l of AZD-2281 and 500 nmol/l of ABT-888, in combination with 0, 4, 8, and 12 Gy external beam radiation, showed a 5.2, 7.1, 10.1, and 33.1% radiosensitization. A measure of 500 nmol/l AZD-2281 and ABT-888 significantly reduced the percentage of viable cells on days 3-5 compared with controls. The maximal relative reduction in viable cells was 78.5%, and this occurred with AZD-2281 (500 nmol/l) on day 5. AZD-2281 revealed a higher number of double-stranded breaks with confocal microscopy than did ABT-888. Two hours after incubation of Raji cells with 500 nmol/l of AZD-2281 or ABT-888, the colorimetric PARP activity assay showed a reduction of 30.36% with ABT-888 and of 47.8% with AZD-2281. Combining AZD-2281 (500 nmol/l) with 0, 5 μCi (0.185 MBq), 10 μCi (0.37 MBq) and 20 μCi (0.74 MBq) ¹³¹I-tositumomab revealed a significant reduction in cell viability after 24 h with 5 μCi (0.185 MBq) (P<0.01) and 10 μCi (0.37 MBq) (P<0.01) radiation dose.
PARP inhibitors AZD-2281 and ABT-888 are highly radiosensitizing agents when used before external beam radiation and ¹³¹I-tositumomab.
评估两种不同的聚（ADP - 核糖）聚合酶（PARP）抑制剂与外照射及碘 - 托西莫单抗联合使用时，对非霍奇金淋巴瘤细胞系的潜在放射增敏能力。
将处于对数生长期、感染了爱泼斯坦 - 巴尔病毒且经慢病毒转染绿色荧光蛋白和荧光素酶的人Raji淋巴瘤细胞，在外照射前24小时与不同剂量的AZD - 2281和ABT - 888孵育。使用500 nmol/l浓度的AZD - 2281和ABT - 888评估Raji淋巴瘤细胞在5天内的生长曲线。使用H2AX抗体和共聚焦显微镜直观评估双链断裂的数量。使用比色法PARP检测试剂盒，在与AZD - 2281（500 nmol/l）和ABT - 888孵育2小时后测量细胞内PARP活性。24小时后评估500 nmol/l的AZD - 2281与不同剂量碘 - 托西莫单抗联合使用的放射增敏效果。
500 nmol/l的AZD - 2281和500 nmol/l的ABT - 888与0、4、8和12 Gy外照射联合使用时，放射增敏率分别为5.2%、7.1%、10.1%和33.1%。与对照组相比，500 nmol/l的AZD - 2281和ABT - 888在第3 - 5天显著降低了活细胞百分比。活细胞的最大相对减少率为78.5%，这在第5天由500 nmol/l的AZD - 2281导致。共聚焦显微镜显示，与ABT - 888相比，AZD - 2281导致更多的双链断裂。在Raji细胞与5 nmol/l的AZD - 2281或ABT - 888孵育2小时后，比色法PARP活性检测显示ABT - 888使PARP活性降低30.36%，AZD - 2281使PARP活性降低47.8%。500 nmol/l的AZD - 2281与0、5 μCi（0.185 MBq）、10 μCi（0.37 MBq）和20 μCi（0.74 MBq）的¹³¹I - 托西莫单抗联合使用时，在24小时后，5 μCi（0.185 MBq）（P < 0.01）和10 μCi（0.37 MBq）（P < 0.01）辐射剂量下，细胞活力显著降低。
PARP抑制剂AZD - 228l和ABT - 888在与外照射及¹³¹I - 托西莫单抗联合使用前是高效的放射增敏剂。
