ATR pathway inhibition is synthetically lethal in cancer cells with ERCC1 deficiency

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• The DNA damage response (DDR) is crucial for cancer cell survival under replication stress.
• ATR (Ataxia Telangiectasia and Rad3-related) and CHEK1 (Checkpoint Kinase 1) are key kinases in the DDR pathway.
• ATR inhibitors have shown synthetic lethal interactions with specific genetic deficiencies and overexpression profiles.

Purpose of the Study:

• To systematically screen for synthetic lethal interactions with ATR pathway-targeted drugs.
• To identify potential therapeutic strategies for cancer treatment based on these interactions.
• To evaluate the clinical utility of ATR pathway inhibitors in specific cancer contexts.

Main Methods:

• Conducted a systematic screen to identify synthetic lethal interactions with ATR pathway inhibitors.
• Assessed the impact of ERCC1 deficiency on cancer cell sensitivity to ATR/CHEK1 inhibitors.
• Utilized triple-negative breast cancer and non-small cell lung cancer cell lines for validation.

Main Results:

• Reduced ATR pathway function itself yielded the strongest synthetic lethal interaction.
• Loss of the ERCC1-XPF endonuclease (ERCC4) was found to be synthetic lethal with ATR pathway inhibitors.
• ERCC1-deficient cells showed increased DNA damage and S-phase arrest upon ATR inhibition.
• ERCC1-depleted triple-negative breast cancer and non-small cell lung cancer cells demonstrated heightened sensitivity to ATR pathway drugs.

Conclusions:

• ATR pathway-targeted drugs may be particularly useful in cancers with compromised ATR pathway function.
• Cancers with reduced ERCC4 activity are potential candidates for ATR pathway inhibitor therapy.
• The synthetic lethal interaction between ERCC1 deficiency and ATR inhibition offers a promising therapeutic avenue.