Background/Objectives: The clinical challenges of PARP inhibitors in ovarian cancer include the lack of effective maintenance regimens for homologous recombination proficiency (HRP) patients and the emergence of acquired resistance in initially responsive homologous recombination deficiency (HRD) patients. This study aims to explore the synergistic effect and molecular mechanism of the bispecific tyrosine phosphorylation-regulated kinase 1B (DYRK1B) inhibitor AZ191 combined with the PARP inhibitor Niraparib on high-grade serous ovarian cancer (HGSOC). Methods: This study first explored the expression and prognostic significance of DYRK1B in ovarian cancer through bioinformatics analysis. Subsequently, the therapeutic effect of the DYRK1B inhibitor AZ191 combined with Niraparib on HGSOC cells and organoids was evaluated by MTT examination. Flow cytometry and Western blot were used to investigate the synergistic mechanism between the two agents. Results: Bioinformatics analysis shows that the high expression of DYRK1B in serous ovarian cancer is associated with poor prognosis of the patients. The experiments in vitro have shown that the DYRK1B inhibitor AZ191 can enhance the therapeutic effect of Niraparib on HGSOC cells and organoids, whether HRD-positive or not. Mechanistic studies have shown that the combination of AZ191 and Niraparib can synergistically increase the accumulation of DNA damage, thereby intensifying the apoptosis of HGSOC cells. In addition, the combination therapy induces ferroptosis by inhibiting the Nrf2/SLC7A11/GPX4 axis, thereby exerting cytotoxic effects. Conclusions: Our results uncover a novel mechanism by which inhibiting DYRK1B enhances the anti-HGSOC efficacy of Niraparib and may offer a promising treatment strategy to improve the maintenance therapy in both HRD and HRP ovarian cancer patients.
Gao et al. (Mon,) studied this question.