EWSR1-ATF1 dependent 3D connectivity regulates oncogenic and differentiation programs in Clear Cell Sarcoma

Area of Science:

• Oncology
• Epigenetics
• Cancer Biology

Background:

• Chromosomal translocations create oncogenic fusion proteins crucial in cancer development.
• EWSR1-transcription factor fusions are potent oncogenes that alter gene expression programs.
• Clear Cell Sarcoma (CCS) is an aggressive cancer characterized by the EWSR1-ATF1 fusion gene.

Purpose of the Study:

• To define the epigenetic and 3D genome landscape of Clear Cell Sarcoma.
• To understand the regulatory mechanisms of the EWSR1-ATF1 fusion oncogene in CCS.
• To identify the cell of origin for Clear Cell Sarcoma.

Main Methods:

• Epigenetic profiling of Clear Cell Sarcoma tumors.
• Analysis of 3D genome connectivity and chromatin accessibility.
• Functional studies involving EWSR1-ATF1 depletion.

Main Results:

• EWSR1-ATF1 exhibits unique DNA binding, requiring the EWSR1 domain for ATF1 retargeting.
• The fusion protein activates chromatin at new distal sites, forming a 3D network controlling oncogenic and differentiation signatures in CCS.
• EWSR1-ATF1 depletion alters 3D genome organization, revealing regulatory circuits promoting neural crest development.

Conclusions:

• EWSR1-ATF1 establishes oncogenic regulatory networks in CCS through epigenetic mechanisms.
• The findings suggest neural crest lineage precursor cells as the likely origin of Clear Cell Sarcoma.
• Understanding these mechanisms offers potential therapeutic targets for CCS.