Histone Deacetylase Inhibitors Repress Tumoral Expression of the Proinvasive Factor RUNX2

Area of Science:

• Molecular Biology
• Cancer Research
• Epigenetics

Background:

• Aberrant reactivation of embryonic pathways is common in cancer.
• The transcription factor RUNX2 is crucial in development and reactivated in tumor progression and metastasis.

Purpose of the Study:

• To elucidate the molecular mechanisms controlling RUNX2 expression and its aberrant reactivation in cancer.
• To investigate the role of a newly identified regulatory element in RUNX2 gene expression.

Main Methods:

• Identification and characterization of a novel enhancer element within the RUNX2 gene.
• Analysis of RUNX2 promoter activation and expression regulation in cancer cells.
• Assessment of the impact of histone deacetylase inhibitors (HDACi) on RUNX2 expression and transcription complexes.

Main Results:

• A new regulatory enhancer within the RUNX2 gene was identified, controlling its promoter activity and expression in cancer cells.
• HDAC inhibitors profoundly inhibit RUNX2 expression by disrupting the transcription-activating complex on this enhancer.
• RUNX2 repression by HDACi is crucial for their cytotoxic activity in cancer.

Conclusions:

• The identified enhancer is a key regulator of RUNX2 expression in cancer.
• Targeting this enhancer offers a potential strategy to counteract RUNX2's oncogenic function.
• HDAC inhibitors exert anticancer effects by repressing essential oncogenic factors like RUNX2, in addition to reactivating tumor suppressors.