SLFN11 Blocks Stressed Replication Forks Independently of ATR

Area of Science:

• Molecular Biology
• Cancer Biology
• Genetics

Background:

• Schlafen-11 (SLFN11) is a key protein that sensitizes cancer cells to DNA-damaging chemotherapy.
• The precise mechanism by which SLFN11 enhances therapy response, particularly at the replication fork level, remains incompletely understood.

Purpose of the Study:

• To elucidate the molecular mechanism of SLFN11 action at stressed replication forks.
• To investigate the role of SLFN11 in blocking DNA replication fork progression and inducing cell death.

Main Methods:

• Utilized camptothecin and CHK1 inhibitor Prexasertib to induce replication stress in cancer cells.
• Employed techniques to analyze protein-chromatin interactions, including SLFN11 binding to RPA1 and MCM3 at replication foci.
• Investigated the functional domains of SLFN11, specifically the ATPase domain, in relation to its cellular activities.

Main Results:

• SLFN11 binds tightly to chromatin at stressed replication forks via RPA1 and MCM3.
• SLFN11 selectively blocks replication fork progression and induces chromatin opening without inhibiting replication initiation.
• The ATPase domain of SLFN11 is critical for chromatin opening, replication block, and cell death.

Conclusions:

• SLFN11 is recruited to stressed replication forks with extended RPA filaments.
• SLFN11 functions by altering chromatin structure at replication sites, leading to replication arrest and cell death.
• This mechanism highlights SLFN11 as a crucial mediator in sensitizing cancer cells to DNA-targeted therapies.