Live-Cell Imaging Shows Uneven Segregation of Extrachromosomal DNA Elements and Transcriptionally Active Extrachromosomal DNA Hubs in Cancer
Abstract
Oncogenic extrachromosomal DNA elements (ecDNA) play an important role in tumor evolution, but our understanding of ecDNA biology is limited. We determined the distribution of single-cell ecDNA copy number across patient tissues and cell line models and observed how cell-to-cell ecDNA frequency varies greatly. The exceptional intratumoral heterogeneity of ecDNA suggested ecDNA-specific replication and propagation mechanisms. To evaluate the transfer of ecDNA genetic material from parental to offspring cells during mitosis, we established the CRISPR-based ecTag method. ecTag leverages ecDNA-specific breakpoint sequences to tag ecDNA with fluorescent markers in living cells. Applying ecTag during mitosis revealed disjointed ecDNA inheritance patterns, enabling rapid ecDNA accumulation in individual cells. After mitosis, ecDNAs clustered into ecDNA hubs, and ecDNA hubs colocalized with RNA polymerase II, promoting transcription of cargo oncogenes. Our observations provide direct evidence for uneven segregation of ecDNA and shed new light on mechanisms through which ecDNAs contribute to oncogenesis.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 01, 2022
- Source ID
- 10.1158/2159-8290.cd-21-1376
Entities
People
- Albert Cheng
- Amit D Gujar
- Dacheng Zhao
- Eunhee Yi
- Hoon Kim
- Kevin C. Johnson
- Megan L. Costa
- Molly Guthrie
- Nathaniel Jillette
- Patricia A. Clow
- Qianru Yu
- Roel G W Verhaak
- Samirkumar Amin
- Sunit Das
Organizations
- American Brain Tumor Association
- American Cancer Society
- National Institutes of Health
- Sungkyunkwan University
- United States Department of Defense
- University of Connecticut Health Center
- University of Toronto