Friday, December 22, 2023

Irreversible inhibition of TRF2TRFH recruiting functions by a covalent cyclic peptide induces telomeric replication stress in cancer cells

Sobinoff, Alexander P.; Di Maro, Salvatore; Low, Ronnie R.J.; Benedetti, Rosaria; Tomassi, Stefano; D'Aniello, Antonia; Russo, Rosita; Baglivo, Ilaria; Chianese, Ugo; Pedone, Paolo V.; Chambery, Angela; Cesare, Anthony J.;  Altucci, Lucia; Pickett, Hilda A.,; Cosconati, Sandro

Cell Chemical Biology, 2023

 doi: 10.1016/j.chembiol.2023.11.008

The TRF2 shelterin component is an essential regulator of telomere homeostasis and genomic stability. Mutations in the TRF2TRFH domain physically impair t-loop formation and prevent the recruitment of several factors that promote efficient telomere replication, causing telomeric DNA damage. Here, we design, synthesize, and biologically test covalent cyclic peptides that irreversibly target the TRF2TRFH domain. We identify APOD53 as our most promising compound, as it consistently induces a telomeric DNA damage response in cancer cell lines. APOD53 forms a covalent adduct with a reactive cysteine residue present in the TRF2TRFH domain and induces phenotypes consistent with TRF2TRFH domain mutants. These include induction of a telomeric DNA damage response, increased telomeric replication stress, and impaired recruitment of RTEL1 and SLX4 to telomeres. We demonstrate that APOD53 impairs cancer cell growth and find that co-treatment with APOD53 can exacerbate telomere replication stress caused by the G4 stabilizer RHPS4 and low dose aphidicolin (APH).



Discovery of a Tunable Heterocyclic Electrophile 4-Chloro-pyrazolopyridine That Defines a Unique Subset of Ligandable Cysteines

Hong-Rae Kim, David P. Byun, Kalyani Thakur, Jennifer Ritchie, Yixin Xie, Ronald Holewinski, Kiall F. Suazo, Mckayla Stevens, Hope Liechty, ...