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The CHK1 Inhibitor Prexasertib Exhibits Monotherapy Activity in High-Grade Serous Ovarian Cancer Models and Sensitizes to PARP Inhibition. | LitMetric

AI Article Synopsis

  • PARP inhibitors are used to treat high-grade serous ovarian cancers (HGSOC), but resistance due to DNA repair mechanisms is a major challenge, prompting research into prexasertib, a CHK1 inhibitor, alone and with olaparib.
  • In tests with various HGSOC tumor models, prexasertib showed antitumor effects even in cases resistant to olaparib, and its combination with olaparib led to enhanced tumor growth inhibition.
  • The study revealed that prexasertib not only induced DNA damage in cancer cells but also increased sensitivity to PARP inhibitors, reversing the cancer's ability to repair itself.

Article Abstract

Purpose: PARP inhibitors are approved for the treatment of high-grade serous ovarian cancers (HGSOC). Therapeutic resistance, resulting from restoration of homologous recombination (HR) repair or replication fork stabilization, is a pressing clinical problem. We assessed the activity of prexasertib, a checkpoint kinase 1 (CHK1) inhibitor known to cause replication catastrophe, as monotherapy and in combination with the PARP inhibitor olaparib in preclinical models of HGSOC, including those with acquired PARP inhibitor resistance.

Experimental Design: Prexasertib was tested as a single agent or in combination with olaparib in 14 clinically annotated and molecularly characterized luciferized HGSOC patient-derived xenograft (PDX) models and in a panel of ovarian cancer cell lines. The ability of prexasertib to impair HR repair and replication fork stability was also assessed.

Results: Prexasertib monotherapy demonstrated antitumor activity across the 14 PDX models. Thirteen models were resistant to olaparib monotherapy, including 4 carrying mutation. The combination of olaparib with prexasertib was synergistic and produced significant tumor growth inhibition in an olaparib-resistant model and further augmented the degree and durability of response in the olaparib-sensitive model. HGSOC cell lines, including those with acquired PARP inhibitor resistance, were also sensitive to prexasertib, associated with induction of DNA damage and replication stress. Prexasertib also sensitized these cell lines to PARP inhibition and compromised both HR repair and replication fork stability.

Conclusions: Prexasertib exhibits monotherapy activity in PARP inhibitor-resistant HGSOC PDX and cell line models, reverses restored HR and replication fork stability, and synergizes with PARP inhibition.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6801076PMC
http://dx.doi.org/10.1158/1078-0432.CCR-19-0448DOI Listing

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