Investigating synthetic lethality and PARP inhibitor resistance in pancreatic cancer through enantiomer differential activity
The RAD51-BRCA2 interaction is central to DNA repair through homologous recombination. Emerging evidence indicates RAD51 overexpression and its correlation with chemoresistance in various cancers, suggesting RAD51-BRCA2 inhibition as a compelling avenue for intervention. We previously showed that combining olaparib (a PARP inhibitor (PARPi)) with RS-35d (a BRCA2-RAD51 inhibitor) was efficient in killing pancreatic ductal adenocarcinoma (PDAC) cells. However, RS-35d impaired cell viability even when administered alone, suggesting potential off-target effects. Here, through multiple, integrated orthogonal biological approaches in different 2D and 3D PDAC cultures, we characterised RS-35d enantiomers, in terms of mode of action and single contributions. By differentially inhibiting both RAD51-BRCA2 interaction and sensor kinases ATM, ATR and DNA-PK, RS-35d enantiomers exhibit a 'within-pathway synthetic lethality' profile. To the best of our knowledge, this is the first reported proof-of-concept single small molecule capable of demonstrating this built-in synergism. In addition, RS-35d effect on BRCA2-mutated, olaparib-resistant PDAC cells suggests that this compound may be effective as an anticancer agent possibly capable of overcoming PARPi resistance. Our results demonstrate the potential of synthetic lethality, with its diversified applications, to propose new and concrete opportunities to effectively kill cancer cells while limiting side effects and potentially overcoming emerging drug resistance.
Authors
- Fulvia Farabegoli (ORCID: https://orcid.org/0000-0001-6254-9443)
- Marinella Roberti (ORCID: https://orcid.org/0000-0001-9807-2886)
- Stefania Girotto (ORCID: https://orcid.org/0000-0002-0339-6675)
- Andrea Cavalli (ORCID: https://orcid.org/0000-0002-6370-1176)
- Giorgio Oliviero (ORCID: https://orcid.org/0000-0002-1257-359X)
- Daniele Tedesco (ORCID: https://orcid.org/0000-0003-2585-7791)
- Marina Veronesi (ORCID: https://orcid.org/0000-0001-8491-8844)
- Laura Poppi (ORCID: https://orcid.org/0000-0002-7353-8237)
- Greta Bagnolini (ORCID: https://orcid.org/0000-0001-6237-1235)
- Federico Falchi (ORCID: https://orcid.org/0000-0001-7385-649X)
- Andrea Ciamarone (ORCID: https://orcid.org/0009-0001-7841-1964)
- Mirco Masi (ORCID: https://orcid.org/0000-0003-0919-5206)
- Viola Previtali (ORCID: https://orcid.org/0000-0001-5396-336X)
- Shannon R. Nelson (ORCID: https://orcid.org/0000-0003-3014-6679)
- Nicola Tirelli (ORCID: https://orcid.org/0000-0002-4879-3949)
- Naomi Walsh (ORCID: https://orcid.org/0000-0002-2178-3564)
- Samuel H. Myers (ORCID: https://orcid.org/0000-0002-9781-2376)
- Giuseppina Di Stefano (ORCID: https://orcid.org/0000-0003-0375-0176)
- Kieran Wynne (ORCID: https://orcid.org/0000-0001-5759-5285)
- Giulia Varignani
- Giovanni Ferrandi (ORCID: https://orcid.org/0009-0004-1656-2961)
- Jose Antonio Ortega (ORCID: https://orcid.org/0000-0003-0426-7928)
- Francesca Franco (ORCID: https://orcid.org/0009-0007-6652-4543)
- Ennio Albanesi (ORCID: https://orcid.org/0000-0002-8794-7111)
Institutions
- University College Dublin (IE)
- University of Perugia (IT)
- Italian Institute of Technology (IT)
- Institute of Organic Synthesis and Photoreactivity (IT)
- National Research Council (IT)
- Institute of Polymers, Composites and Biomaterials (IT)
- Dublin City University (IE)
- École Polytechnique Fédérale de Lausanne (CH)
- University of Bologna (IT)
Publication Details
- Journal
- Cell Death Discovery
- Published
- 2025-03-16
- DOI
- https://doi.org/10.1038/s41420-025-02382-3
- Citations
- 7
- Primary Topic
- PARP inhibition in cancer therapy
- Type
- article
- Field-Weighted Citation Impact
- 7.32
Funders
- Ministero dell’Istruzione, dell’Università e della Ricerca
- Associazione Italiana per la Ricerca sul Cancro