Discovery of selective BPTF bromodomain inhibitors by screening and structure-based optimization

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• The Bromodomain and PHD finger containing transcription factor (BPTF) is a key regulator of chromatin transcription implicated in various cancers.
• Targeting BPTF offers a potential therapeutic strategy for cancer treatment.

Purpose of the Study:

• To discover and optimize novel small molecule inhibitors of the BPTF bromodomain.
• To characterize the potency, selectivity, and cellular activity of newly synthesized BPTF inhibitors.

Main Methods:

• Screening-based compound discovery and structure-guided optimization.
• In vitro biochemical assays (ITC) to determine binding affinity (K_D).
• Cocrystallography to elucidate binding modes.
• Cellular thermal shift assay (CETSA) to assess target engagement in cells.
• Western blotting to evaluate target gene expression (c-MYC).

Main Results:

• Identification of Cpd1 with micromolar affinity for the BPTF bromodomain.
• Synthesis of potent and selective inhibitors Cpd8 (K_D = 428 nM) and Cpd10 (K_D = 655 nM).
• Cocrystal structure revealed the binding mode of Cpd8.
• Cpd8 and Cpd10 demonstrated target engagement in cells via CETSA.
• Cpd8 effectively downregulated c-MYC expression in A549 cells.

Conclusions:

• Cpd8 and Cpd10 represent promising BPTF inhibitors with demonstrated in vitro and cellular activity.
• These compounds provide valuable tools for further investigation of BPTF's role in cancer.
• The discovered inhibitors hold potential for future therapeutic development against BPTF-driven cancers.