Inverted logic of ecDNA localization converts nuclear periphery into oncogenic transcription hubs in cancer
TL;DR
It is shown that ecDNAs, in contrast to chromosomal DNA, preferentially localize to the nuclear periphery yet resist peripheral gene silencing, and single-molecule multi-omic sequencing and imaging-based CRISPR screening demonstrate enhanced ecDNA hub formation, H3K27ac and H3K9me3 bivalency, late DNA replication, long-range CpG hypomethylation, and increased transcriptional output when ecDNAs localize
Abstract
Extrachromosomal DNA (ecDNA) is a major driver of cancer pathogenesis, however, its spatial organization in the nucleus is not currently understood. Here we show that ecDNAs, in contrast to chromosomal DNA, preferentially localize to the nuclear periphery yet resist peripheral gene silencing. Single-molecule multi-omic sequencing and imaging-based CRISPR screening demonstrate enhanced ecDNA hub formation, H3K27ac and H3K9me3 bivalency, late DNA replication, long-range CpG hypomethylation, and increased transcriptional output when ecDNAs localize to the nuclear periphery. EcDNA anchors to the nuclear lamina through H3K9me3-dependent interactions with the Lamin B Receptor (LBR), which if interrupted, results in inward migration of ecDNA particles, reduced ecDNA congregation, and decreased transcription of ecDNA-encoded genes. These results reveal inherent advantages of the spatial organization of ecDNA that are not available to chromosomal DNA, enhancing ecDNA congregation and amplifying oncogenic transcriptional output, by localizing to the nuclear periphery of cancer cells.