A Genetic Map of the Response to DNA Damage in Human Cells

Abstract

The response to DNA damage is critical for cellular homeostasis, tumor suppression, immunity and gametogenesis. In order to provide an unbiased and global view of the DNA damage response in human cells, we undertook 28 CRISPR/Cas9 screens against 25 genotoxic agents in the retinal pigment epithelium-1 (RPE1) cell line. These screens identified 840 genes whose loss causes either sensitivity or resistance to DNA damaging agents. Mining this dataset, we uncovered that ERCC6L2, which is mutated in a bone-marrow failure syndrome, codes for a canonical non-homologous end-joining pathway factor; that the RNA polymerase II component ELOF1 modulates the response to transcription-blocking agents and that the cytotoxicity of the G-quadruplex ligand pyridostatin involves trapping topoisomerase II on DNA. This map of the DNA damage response provides a rich resource to study this fundamental cellular system and has implications for the development and use of genotoxic agents in cancer therapy.

HERC2 inactivation abrogates nucleolar localization of RecQ helicases BLM and WRN

“…In addition to inhibition of Pol I activity, CX-5461 possesses an intrinsic activity as a G4 stabilizer 38 . CX-5461 also promotes topoisomerase II trapping possibly following G4 stabilization 39,40 . We have previously reported that HERC2 suppresses G4 formation of DNA in a manner which is epistatic to BLM and WRN.…”

DNA folds threaten genetic stability and can be leveraged for chemotherapy

“…Multiple repair mechanisms exist for all types of DNA damage ( Fig. 1), 3,33,79,80 and a large degree of overlap exists within the multiple DNA repair pathways and with double-strand break (DSB) repair pathways. 69 Singlestrand breaks (SSBs) are the most common DNA damage occurring throughout a cell's lifetime, with a large amount being generated endogenously by reactive oxygen species (ROS) generating SSB directly or resulting in DNA lesions processed by DNA glycosylases and apurinic/apyrimidinic endonucleases (APEs).…”

Advances in ovarian cancer, from biology to treatment

“…A study using CRISPR-Cas9 to generate a functional genetic map of DNA damage responses to 27 genotoxic agents in retinal pigment epithelial cells has created a rich resource to study this fundamental cellular system, with implications for the development and use of genotoxic agents in OC therapy. These comprehensive screens identified 890 genes whose loss contributes to either sensitivity or resistance to DNA-damaging agents 5 . They showed that pyridostatin, which induces guanine (G) quadruplexes, induces DNA damage and cell-cycle arrest through a process that involves the trapping of topoisomerase II on DNA 5 , a concept that will be explored in upcoming trials of G-quadruplex stabilization in OC.…”

“…These comprehensive screens identified 890 genes whose loss contributes to either sensitivity or resistance to DNA-damaging agents 5 . They showed that pyridostatin, which induces guanine (G) quadruplexes, induces DNA damage and cell-cycle arrest through a process that involves the trapping of topoisomerase II on DNA 5 , a concept that will be explored in upcoming trials of G-quadruplex stabilization in OC.…”