Functional CRISPR screen identifies AP1-associated enhancer regulating FOXF1 to modulate oncogene-induced senescence

Area of Science:

• Genomics
• Cancer Biology
• Molecular Biology

Background:

• Functional characterization of non-coding genomic elements is challenging.
• Oncogene-induced senescence is a critical tumor suppressor mechanism.
• Bypassing oncogene-induced senescence is essential for cancer development.

Purpose of the Study:

• To identify enhancer elements critical for establishing oncogene-induced senescence.
• To understand the regulatory mechanisms controlling this senescence pathway.

Main Methods:

• Genome-wide profiling of enhancer-RNAs (eRNAs) to identify activated enhancers.
• CRISPR-Cas9 functional genomic screening targeting AP-1 regulated enhancers.
• DNA motif analysis to identify key transcription factors.

Main Results:

• AP-1 was identified as a major regulator of oncogene-induced senescence.
• A novel enhancer, Enh^AP1-OIS1, was identified and validated.
• Mutation of the AP-1 binding site in Enh^AP1-OIS1 led to bypass of oncogene-induced senescence.
• FOXF1 was identified as the gene regulated by Enh^AP1-OIS1, mediating its effect on senescence.

Conclusions:

• A novel regulatory cascade involving AP-1 and FOXF1 in oncogene-induced senescence was elucidated.
• CRISPR-based functional screens are powerful tools for deciphering non-coding element functions.
• Understanding this pathway provides insights into tumorigenesis and potential therapeutic targets.