Increased Replication Stress Determines ATR Inhibitor Sensitivity in Neuroblastoma Cells.

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• High-risk neuroblastoma (NB) has a poor survival rate (<50%) despite intensive therapy.
• MYCN amplification, present in 25% of NB cases, defines high-risk disease and is associated with poor outcomes.

Purpose of the Study:

• To investigate the role of replication stress in sensitizing high-risk neuroblastoma to ATR inhibitors.
• To explore the combined effects of ATR and PARP inhibition on NB cell death.

Main Methods:

• Utilized pre-clinical models of high-risk neuroblastoma.
• Administered ATR inhibitors (VE-821, AZD6738) and PARP inhibitor (Olaparib).
• Assessed replication stress, cell cycle checkpoints, and cell death.

Main Results:

• MYCN amplification-induced replication stress directly increases sensitivity to ATR inhibitors.
• PARP inhibition causes replication stress and ATR activation, sensitizing NB cells to ATR inhibition regardless of MYCN status.
• Combined ATR and PARP inhibition leads to synergistic cell death, particularly in MYCN-expressing cells, by increasing stalled replication forks and abrogating cell cycle checkpoints.

Conclusions:

• Increased replication stress, whether from MYCN expression, PARP inhibition, or chemotherapy, enhances sensitivity to ATR inhibition.
• ATR and PARP inhibitors represent a promising therapeutic strategy for high-risk neuroblastoma.