1. Academic Validation
  2. DDX11 loss causes replication stress and pharmacologically exploitable DNA repair defects

DDX11 loss causes replication stress and pharmacologically exploitable DNA repair defects

  • Proc Natl Acad Sci U S A. 2021 Apr 27;118(17):e2024258118. doi: 10.1073/pnas.2024258118.
Nanda Kumar Jegadesan 1 Dana Branzei 2 3
Affiliations

Affiliations

  • 1 The FIRC Institute of Molecular Oncology, Italian Foundation for Cancer Research, 20139, Milan, Italy.
  • 2 The FIRC Institute of Molecular Oncology, Italian Foundation for Cancer Research, 20139, Milan, Italy; dana.branzei@ifom.eu.
  • 3 Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, 27100, Pavia, Italy.
Abstract

DDX11 encodes an iron-sulfur cluster DNA helicase required for development, mutated, and overexpressed in cancers. Here, we show that loss of DDX11 causes replication stress and sensitizes Cancer cells to DNA damaging agents, including poly ADP ribose polymerase (PARP) inhibitors and platinum drugs. We find that DDX11 helicase activity prevents chemotherapy drug hypersensitivity and accumulation of DNA damage. Mechanistically, DDX11 acts downstream of 53BP1 to mediate homology-directed repair and RAD51 focus formation in manners nonredundant with BRCA1 and BRCA2. As a result, DDX11 down-regulation aggravates the chemotherapeutic sensitivity of BRCA1/2-mutated cancers and resensitizes chemotherapy drug-resistant BRCA1/2-mutated Cancer cells that regained homologous recombination proficiency. The results further indicate that DDX11 facilitates recombination repair by assisting double strand break resection and the loading of both RPA and RAD51 on single-stranded DNA substrates. We propose DDX11 as a potential target in cancers by creating pharmacologically exploitable DNA repair vulnerabilities.

Keywords

BRCA1/2; DDX11; chemotherapy; homologous recombination; replication stress.

Figures
Products