Artesunate potentiates poly (ADP-ribose) polymerase inhibitor efficacy in ovarian cancer through RAD51-mediated homologous recombination repair impairment.

چکیده اصلی

BACKGROUND: The homologous recombination repair (HRR) RAD51 recombinase is essential for ensuring accurate DNA repair, and its expression levels are inversely correlated with Poly (ADP-ribose) Polymerase inhibitor (PARPi) sensitivity. Artesunate (ART), a semisynthetic water-soluble sesquiterpene lactone derived from artemisinin, a natural product of Artemisia annua, was previously identified from an HRR reporting system as a potential HRR modulator, suggesting its utility as a PARPi sensitizer. METHODS: The clinical relevance of RAD51 was assessed using the TCGA database. In vitro studies employed A2780 and SKOV3 ovarian cancer cell lines, utilizing RAD51 siRNA, the inhibitor IBR2, and ART alone or in combination with Olaparib (Ola). Used cell counting kit-8, colony formation, and EdU assays to evaluate cell proliferation.; apoptosis by flow cytometry; and DNA damage by γ-H2AX immunofluorescence and comet assays. Protein levels were analyzed by Western blotting (p-ATM, γ-H2AX, RAD51). The ART-RAD51 interaction was validated via cellular thermal shift assay, drug affinity responsive target stability, and molecular docking. In vivo efficacy and safety were evaluated in a nude mouse xenograft model. RESULTS: RAD51 expression was correlated with ovarian cancer progression, and PARPi treatment itself promoted RAD51 expression. siRNA and inhibitior of RAD51 sensitized ovarian cells to Ola. We identified ART as a direct inhibitor of RAD51, which binds to RAD51 and promotes its protein degradation, thereby inhibiting HRR. The combination of ART and Ola significantly increased DNA damage, inhibited proliferation, and induced apoptosis in vitro. This combination also potently suppressed tumor growth in vivo without observable significant toxicity. CONCLUSION: Our findings establish RAD51 as a key target for addressing PARPi-resistant in ovarian cancer. We demonstrate that ART counteracts this resistance through directly binding to and degrading RAD51, thereby inhibiting HRR. The ART-Ola combination presents a novel, synergistic, and well-tolerated strategy in preclinical models, providing a strong mechanistic rationale for future clinical translation.

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