Pignochino Ymera, Capozzi Federica, D'Ambrosio Lorenzo, Dell'Aglio Carmine, Basiricò Marco, Canta Marta, Lorenzato Annalisa, Vignolo Lutati Francesca, Aliberti Sandra, Palesandro Erica, Boccone Paola, Galizia Danilo, Miano Sara, Chiabotto Giulia, Napione Lucia, Gammaitoni Loretta, Sangiolo Dario, Benassi Maria Serena, Pasini Barbara, Chiorino Giovanna, Aglietta Massimo, Grignani Giovanni
Sarcoma Unit, Medical Oncology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo, Torino, Italy.
Department of Oncology, University of Torino Medical School, Candiolo, Torino, Italy.
Mol Cancer. 2017 Apr 28;16(1):86. doi: 10.1186/s12943-017-0652-5.
Enhancing the antitumor activity of the DNA-damaging drugs is an attractive strategy to improve current treatment options. Trabectedin is an isoquinoline alkylating agent with a peculiar mechanism of action. It binds to minor groove of DNA inducing single- and double-strand-breaks. These kinds of damage lead to the activation of PARP1, a first-line enzyme in DNA-damage response pathways. We hypothesized that PARP1 targeting could perpetuate trabectedin-induced DNA damage in tumor cells leading finally to cell death.
We investigated trabectedin and PARP1 inhibitor synergism in several tumor histotypes both in vitro and in vivo (subcutaneous and orthotopic tumor xenografts in mice). We searched for key determinants of drug synergism by comparative genomic hybridization (aCGH) and gene expression profiling (GEP) and validated their functional role.
Trabectedin activated PARP1 enzyme and the combination with PARP1 inhibitors potentiated DNA damage, cell cycle arrest at G2/M checkpoint and apoptosis, if compared to single agents. Olaparib was the most active PARP1 inhibitor to combine with trabectedin and we confirmed the antitumor and antimetastatic activity of trabectedin/olaparib combination in mice models. However, we observed different degree of trabectedin/olaparib synergism among different cell lines. Namely, in DMR leiomyosarcoma models the combination was significantly more active than single agents, while in SJSA-1 osteosarcoma models no further advantage was obtained if compared to trabectedin alone. aCGH and GEP revealed that key components of DNA-repair pathways were involved in trabectedin/olaparib synergism. In particular, PARP1 expression dictated the degree of the synergism. Indeed, trabectedin/olaparib synergism was increased after PARP1 overexpression and reduced after PARP1 silencing.
PARP1 inhibition potentiated trabectedin activity in a PARP1-dependent manner and PARP1 expression in tumor cells might be a useful predictive biomarker that deserves clinical evaluation.
增强DNA损伤药物的抗肿瘤活性是改善当前治疗方案的一个有吸引力的策略。曲贝替定是一种异喹啉类烷化剂，具有独特的作用机制。它与DNA小沟结合，诱导单链和双链断裂。这类损伤导致PARP1的激活，PARP1是DNA损伤反应途径中的一线酶。我们假设靶向PARP1可使曲贝替定诱导的肿瘤细胞DNA损伤持续存在，最终导致细胞死亡。
我们在体外和体内（小鼠皮下和原位肿瘤异种移植）研究了曲贝替定与PARP1抑制剂在几种肿瘤组织类型中的协同作用。我们通过比较基因组杂交（aCGH）和基因表达谱分析（GEP）寻找药物协同作用的关键决定因素，并验证其功能作用。
与单一药物相比，曲贝替定激活了PARP1酶，与PARP1抑制剂联合使用可增强DNA损伤、使细胞周期停滞在G2/M期并诱导凋亡。奥拉帕尼是与曲贝替定联合使用时活性最高的PARP1抑制剂，我们在小鼠模型中证实了曲贝替定/奥拉帕尼联合用药的抗肿瘤和抗转移活性。然而，我们在不同细胞系中观察到曲贝替定/奥拉帕尼协同作用的程度不同。具体而言，在DMR平滑肌肉瘤模型中，联合用药比单一药物活性显著更高，而在SJSA-1骨肉瘤模型中，与单独使用曲贝替定相比没有进一步优势。aCGH和GEP显示DNA修复途径的关键成分参与了曲贝替定/奥拉帕尼的协同作用。特别是，PARP1的表达决定了协同作用的程度。事实上，PARP1过表达后曲贝替定/奥拉帕尼的协同作用增强，PARP1沉默后协同作用减弱。
PARP1抑制以PARP1依赖的方式增强了曲贝替定的活性，肿瘤细胞中PARP1的表达可能是一个值得临床评估的有用预测生物标志物。
