Department of Medical Biophysics, Institute of Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
Cells. 2022 Jun 10;11(12):1889. doi: 10.3390/cells11121889.
Olaparib is a poly (ADP-ribose) polymerase inhibitor (PARPi) that inhibits PARP1/2, leading to replication-induced DNA damage that requires homologous recombination repair. Olaparib is often insufficient to treat -mutated () and wild-type () high-grade serous ovarian carcinomas (HGSOCs). We examined the short-term (up to 48 h) efficacy of PARPi treatment on a DNA damage response pathway mediated by ATR and CHK1 kinases in (PEO-1) and (SKOV-3 and OV-90) cells. The combination of ATRi/CHK1i with PARPi was not more cytotoxic than ATR and CHK1 monotherapy. The combination of olaparib with inhibitors of the ATR/CHK1 pathway generated chromosomal abnormalities, independent on status of cells and formed of micronuclei (MN). However, the beneficial effect of the PARPi:ATRi combination on MN was seen only in the PEO1 line. Monotherapy with ATR/CHK1 inhibitors reduced BrdU incorporation due to a slower rate of DNA synthesis, which resulted from elevated levels of replication stress, while simultaneous blockade of PARP and ATR caused beneficial effects only in OV-90 cells. Inhibition of ATR/CHK1 increased the formation of double-strand breaks as measured by increased γH2AX expression at collapsed replication forks, resulting in increased levels of apoptosis. Our findings indicate that ATR and CHK1 inhibitors provoke premature mitotic entry, leading to genomic instability and ultimately cell death.
奥拉帕利是一种聚（ADP-核糖）聚合酶抑制剂（PARPi），可抑制 PARP1/2，导致需要同源重组修复的复制诱导的 DNA 损伤。奥拉帕利通常不足以治疗 -突变（）和野生型（）高级别浆液性卵巢癌（HGSOC）。我们研究了在ATR 和 CHK1 激酶介导的 DNA 损伤反应途径中，PARPi 治疗对 PEO-1（）和 SKOV-3 和 OV-90（）细胞的短期（长达 48 小时）疗效。ATR/CHK1i 与 PARPi 的联合治疗并不比 ATR 和 CHK1 单药治疗更具细胞毒性。奥拉帕利与 ATR/CHK1 通路抑制剂的联合使用会导致染色体异常，与细胞的状态无关，并形成微核（MN）。然而，PARPi：ATR 联合治疗对 MN 的有益作用仅见于 PEO1 系。ATR/CHK1 抑制剂的单药治疗由于 DNA 合成速度较慢而导致 BrdU 掺入减少，这是由于复制应激水平升高所致，而同时阻断 PARP 和 ATR 仅在 OV-90 细胞中产生有益作用。ATR/CHK1 的抑制作用通过增加在崩溃的复制叉处表达的 γH2AX 来增加双链断裂的形成，从而导致细胞凋亡水平增加。我们的研究结果表明，ATR 和 CHK1 抑制剂会引发过早的有丝分裂进入，导致基因组不稳定并最终导致细胞死亡。
