Poster De Conférence Année : 2024

Identification & characterization of a new series of CHK1 inhibitors

Résumé

Genomic DNA is continuously challenged by endogenous and exogenous stressors. To maintain genomic integrity, cells have evolved the DNA damage response (DDR), an integrated response which induces a transcriptional program, control the cell cycle progression and repair DNA. Targeting the DDR is a promising strategy to treat cancers as exemplified with the efficacy of PARP1 inhibitors in BRCA1/BRCA2-deficient cancers. However, cancers are prone to develop resistance to these novel targeted therapies and there is a need for novel molecules, targets and biomarkers to exploit some of their vulnerabilities and circumvent their resistance. To identify novel molecules targeting the DDR, we developed a phenotypical screen to identify sensitizers to DNA damaging agents in the French Chimiothèque Nationale Essentielle. This led to identify a novel molecule synthesized at CERMN, that we named Shuri1, as a sensitizer of proliferative cells to camptothecin, an anticancer agent poisoning DNA topoisomerase 1. A crude preliminary Structure-Activity Relationship was performed using available analogues from CERMN which identified critical positions on the scaffold along with another active analogue. Monitoring the molecular phenotypes induced by Shuri1 and relatives revealed that they induce RPA and γH2AX foci formation in S-phase, in a dose-dependent manner. Using in vitro kinase assays, we demonstrated that they behave as selective CHK1 inhibitors (CHK1i), with a good selectivity as compared to its activity on CHK2. In agreement, Shuri1 is able to block CHK1 autophosphorylation in response to replicative stress and to potentializes hydroxyurea and camptothecin cytotoxic activity on mammalian cells. Through an unbiased approach, we identified a gene whose inactivation in HAP1 and U2OS cells confer a strong resistance to commercial CHK1i (AZD-7762, Prexasertib or MK-8776). Importantly, isogenic cell lines inactivated for this gene were also cross-resistant to Shuri1, thereby providing a cellular validation of its target and activity. Altogether, these data show that phenotypical screens, along with dedicated molecular analysis, can lead to identify novel modulators of the DDR. The use of panels of cell lines resistant to specific class of DDR modulators to perform phenotypical screens represents an attractive avenue for identifying novel DDRi with known mechanism of action and/or to treat resistance.

Fichier non déposé

Dates et versions

hal-04930209 , version 1 (05-02-2025)

Identifiants

  • HAL Id : hal-04930209 , version 1

Citer

Marie-Jeanne Pillaire, Alexandrine Rozié, Peggy Suzanne, Patrick Calsou, Patrick Dallemagne, et al.. Identification & characterization of a new series of CHK1 inhibitors. DNA replication and replication stress, Dec 2024, Montpellier, France. ⟨hal-04930209⟩
93 Consultations
0 Téléchargements

Partager

  • More