Ávila-Arroyo Sonia, Nuñez Gema Santamaría, García-Fernández Luis Francisco, Galmarini Carlos M
Cell Biology and Pharmacogenomics Department, PharmaMar S.A., Madrid, Spain.
J Breast Cancer. 2015 Dec;18(4):329-38. doi: 10.4048/jbc.2015.18.4.329. Epub 2015 Dec 23.
Trabectedin induces synthetic lethality in tumor cells carrying defects in homologous recombinant DNA repair. We evaluated the effect of concomitant inhibition of nucleotide-excision repair and poly (ADP-ribose) polymerase (PARP) activity with trabectedin and PARP inhibitors, respectively, and whether the synthetic lethality effect had the potential for a synergistic effect in breast cancer cell lines. Additionally, we investigated if this approach remained effective in BRCA1-positive breast tumor cells.
We have evaluated the in vitro synergistic effect of combinations of trabectedin and three different PARP inhibitors (veliparib, olaparib, and iniparib) in four breast cancer cell lines, each presenting a different BRCA1 genetic background. Antiproliferative activity, DNA damage, cell cycle perturbations and poly(ADP-ribosyl)ation were assessed by MTT assay, comet assay, flow cytometry and western blot, respectively.
The combination of trabectedin and olaparib was synergistic in all the breast cancer cell lines tested. Our data indicated that the synergy persisted regardless of the BRCA1 status of the tumor cells. Combination treatment was associated with a strong accumulation of double-stranded DNA breaks, G2/M arrest, and apoptotic cell death. Synergistic effects were not observed when trabectedin was combined with veliparib or iniparib.
Collectively, our results indicate that the combination of trabectedin and olaparib induces an artificial synthetic lethality effect that can be used to kill breast cancer cells, independent of BRCA1 status.
曲贝替定可在携带同源重组DNA修复缺陷的肿瘤细胞中诱导合成致死。我们分别评估了曲贝替定与PARP抑制剂联合抑制核苷酸切除修复和聚（ADP - 核糖）聚合酶（PARP）活性的效果，以及这种合成致死效应在乳腺癌细胞系中是否具有协同作用的潜力。此外，我们还研究了这种方法在BRCA1阳性乳腺肿瘤细胞中是否仍然有效。
我们评估了曲贝替定与三种不同PARP抑制剂（维利帕尼、奥拉帕尼和因尼帕尼）联合使用在四种具有不同BRCA1基因背景的乳腺癌细胞系中的体外协同作用。分别通过MTT法、彗星试验、流式细胞术和蛋白质印迹法评估抗增殖活性、DNA损伤、细胞周期扰动和聚（ADP - 核糖）化。
曲贝替定与奥拉帕尼的联合在所有测试的乳腺癌细胞系中均具有协同作用。我们的数据表明，无论肿瘤细胞的BRCA1状态如何，这种协同作用都持续存在。联合治疗与双链DNA断裂的强烈积累、G2/M期阻滞和凋亡性细胞死亡相关。曲贝替定与维利帕尼或因尼帕尼联合使用时未观察到协同作用。
总体而言，我们的结果表明，曲贝替定与奥拉帕尼的联合可诱导一种人工合成致死效应，可用于杀死乳腺癌细胞，而与BRCA1状态无关。
