Positively selected enhancer elements endow osteosarcoma cells with metastatic competence

Area of Science:

• Oncology
• Genomics
• Epigenetics

Background:

• Metastasis involves distinct tumor cell traits separate from tumorigenesis.
• Enhancer elements play a critical role in acquired metastatic phenotypes.

Purpose of the Study:

• Investigate the contribution of enhancer elements to osteosarcoma's metastatic potential.
• Identify and characterize novel regulatory regions associated with metastasis.

Main Methods:

• Epigenomic profiling of primary and metastatic osteosarcoma tumors and cell lines.
• Identification and analysis of metastatic variant enhancer loci (Met-VELs).
• Functional validation through pharmacologic BET inhibition, transcription factor knockdown, and gene inhibition (e.g., F3).

Main Results:

• Significant differences in enhancer activity observed between primary and metastatic osteosarcoma.
• Met-VELs identified as key drivers of gene expression during lung metastasis.
• Targeting Met-VEL-associated gene expression, AP-1 transcription factors, or F3 inhibited osteosarcoma lung metastasis.
• Genetic deletion of a specific Met-VEL at the F3 locus impaired metastatic outgrowth.

Conclusions:

• Met-VELs and their regulated genes are functionally implicated in osteosarcoma metastasis.
• Met-VELs represent potential therapeutic targets for antimetastatic strategies.