A Highly Sensitive Method to Efficiently Profile the Histone Modifications of FFPE Samples.

Area of Science:

• Epigenetics
• Molecular Biology
• Cancer Research

Background:

• Archived formalin-fixed paraffin-embedded (FFPE) tissues are crucial for basic research and translational cancer studies.
• Profiling histone modifications in FFPE tissues is vital for understanding gene regulation in human diseases.
• Current methods require substantial FFPE tissue, limiting detailed analyses.

Purpose of the Study:

• To develop a highly sensitive method for profiling histone modifications in FFPE tissues using minimal sample input.
• To enable better-resolved analyses of epigenetic regulation in archival cancer tissues.

Main Methods:

• Introduced FACT-seq (formalin-fixed paraffin-embedded tissue with antibody-guided chromatin fragmentation with sequencing).
• FACT-seq combines T7-pA-Tn5 transposition with T7 in vitro transcription.
• The method requires a low number of FFPE nuclei for high-quality chromatin profiles.

Main Results:

• FACT-seq successfully generated high-quality chromatin profiles for histone modifications from FFPE tissues.
• A small FFPE tissue section (~4000 nuclei) was sufficient to decode H3K27ac modifications.
• FACT-seq analysis of colorectal and glioblastoma FFPE tissues identified disease-specific super enhancers.

Conclusions:

• FACT-seq provides a sensitive approach to decode histone modifications (e.g., H3K27ac, H3K27me3) in archival FFPE tissues.
• This method allows for a deeper understanding of epigenetic regulation in human diseases.
• FACT-seq facilitates epigenetic studies with limited clinical tissue samples.