TrAEL-seq for WRN inhibitors

Cancers with microsatellite instability (MSI) depend on the WRN helicase enzyme to manage issues during DNA replication caused by long stretches of (TA) repeats in the DNA. Targeting WRN is a promising strategy for treating MSI cancers, and drugs that inhibit WRN are being developed. Through a process called fragment-based screening, we developed powerful and specific drugs that block WRN's action. These drugs effectively slowed down the growth of MSI cancer models in lab and animal studies by acting like WRN is absent, leading to DNA breaks at the long TA repeats and causing DNA damage. The development of these potent and specific drugs targeting WRN in MSI cancers proves that this approach can work and also helps us understand more about WRN's role in biology. We employed Transferase-Activated End Ligation sequencing (TrAEL-seq), a method that captures single-stranded DNA 3′ ends genome-wide and with base pair resolution, to identify the genomic sites of DNA double-strand breaks (DSBs) in MSI cells treated with WRN inhibitors. We used HCT116 cells engineered with an inducible sgRNA system for WRN targeting (i-WRN) as a positive control, along with GSK4532858A-treated HCT116 cells and GSK4532858A-treated KM12 cells