BRD4 facilitates replication stress-induced DNA damage response

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• BRD4 (Bromodomain-containing protein 4) is known to regulate oncogenic gene transcription in various cancers.
• Its role in DNA damage response (DDR) has not been previously elucidated.

Purpose of the Study:

• To investigate the novel function of BRD4 in the DNA damage response (DDR) pathway.
• To explore the therapeutic potential of targeting BRD4 in combination with DDR-targeting agents.

Main Methods:

• Utilized BRD4 inhibitors (JQ1, AZD5153) to assess effects on DNA replication and checkpoint signaling.
• Investigated the synergistic effects of BRD4 inhibition with ATR inhibitor AZD6738 in cancer cell lines and xenograft models.

Main Results:

• BRD4 inhibition led to reduced CHK1 phosphorylation and aberrant DNA replication re-initiation.
• BRD4 inhibition sensitized cancer cells to replication stress agents and synergized with ATR inhibitor AZD6738 for cell killing.
• Synergistic effects were observed in both cell-line and patient-derived xenograft models.

Conclusions:

• BRD4 plays a critical role in DNA replication checkpoint signaling and the DDR.
• Combining BET inhibitors like BRD4 inhibitors with DDR-targeting agents presents a promising strategy for cancer therapy.