Synthetic lethality is an innovative framework for discovering novel anticancer drug candidates. One example is the use of PARP inhibitors (PARPi) in oncology patients with BRCA mutations. Here, we exploit a new paradigm based on the possibility of triggering synthetic lethality using only small organic molecules (dubbed “fully small-molecule-induced synthetic lethality”). We exploited this paradigm to target pancreatic cancer, one of the major unmet needs in oncology. We discovered a dihydroquinolone pyrazoline-based molecule ( 35d ) that disrupts the RAD51-BRCA2 protein–protein interaction, thus mimicking the effect of BRCA2 mutation. 35d inhibits the homologous recombination in a human pancreatic adenocarcinoma cell line. In addition, it synergizes with olaparib (a PARPi) to trigger synthetic lethality. This strategy aims to widen the use of PARPi in BRCA -competent and olaparib-resistant cancers, making fully small-molecule-induced synthetic lethality an innovative approach toward unmet oncological needs.

No abstract

In BRCA2-defective cells, poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitors can trigger synthetic lethality, as two independent DNA-repairing mechanisms are simultaneously impaired. Here, we have pharmacologically induced synthetic lethality, which was triggered by combining two different small organic molecules. When administered with a BRCA2-Rad51 disruptor in nonmutant cells, Olaparib showed anticancer activity comparable to that shown when administered alone in BRCA2-defective cells. This strategy could represent an innovative approach to anticancer drug discovery and could be extended to other synthetic lethality pathways.

No abstract

No abstract