Khoury, A. | bioRxiv Science

bioRxiv2024

Androgen stimulation rapidly reorganizes temporal 3D genome and epigenome states to trigger AR-mediated transcription in prostate cancer.

Androgen receptor (AR)-mediated transcription drives prostate cancer progression and remains a critical therapeutic target. AR activation by androgens triggers nuclear translocation, DNA binding at AR regulatory elements (AREs) and transcription initiation. This process involves co-factors such as FOXA1, epigenetic modifications, and 3D chromatin interactions. However, the temporal coordination of these events during AR-mediated transcription remains poorly understood. Using a time-course androgen stimulation model in prostate cancer cells, we integrated temporal multi-omics data within the MOFA+ framework to dissect AR-mediated transcriptional dynamics. Our analysis revealed that rapid AR binding at gene promoters is crucial for initiating nascent transcription of AR target genes. We identified H3K27 acetylation at flanking AREs, pre-marked by constitutive FOXA1 binding, occurs prior to AR recruitment. Additionally, androgen stimulation induced a temporal early shift in nascent transcription from MYC to AR target genes, associated with transient disruption of 3D chromatin interactions. Finally, we showed that CRISPR-mediated inhibition of AR-associated chromatin contacts suppresses distal linked target genes, demonstrating that dynamic genome architecture is functionally required for AR-driven transcription. Together these findings uncover the dynamic reorganization of 3D chromatin structure and transcription factor binding post-androgen stimulation, resulting in distinct temporal epigenomic states. This work provides new insights into the mechanisms governing AR-mediated transcriptional activation in prostate cancer and highlights the interplay between MYC and AR in regulating transcription in hormone-driven cancers.

genomics↗

bioRxiv2018

Replication timing shapes the cancer epigenome and the nature of chromosomal rearrangements

HighlightsO_LIReplication timing alterations are conserved in cancers of different cell origins\nC_LIO_LILong-range epigenetic deregulation in cancer involves altered replication timing\nC_LIO_LICancer late-replicating loci are hypomethylated and acquire facultative heterochromatin\nC_LIO_LIReplication timing status potentiates cis and trans chromosomal rearrangements\nC_LI\n\nSummaryReplication timing is known to facilitate the establishment of epigenome, however, the intimate connection between DNA replication timing and changes to the genome and epigenome in cancer remain uncharted. Here, we perform Repli-Seq and integrated epigenome analysis and show that early-replicating loci are predisposed to hypermethylation and late-replicating loci to hypomethylation, enrichment of H3K27me3 and concomitant loss of H3K9me3. We find that altered replication timing domains correspond to long-range epigenetically deregulated regions in prostate cancer, and a subset of these domains are remarkably conserved across cancers from different tissue origins. Analyses of 214 prostate and 35 breast cancer genomes reveal that late-replicating DNA is prone to cis and early-replicating DNA to trans chromosomal rearrangements. We propose that differences in epigenetic deregulation related to spatial and temporal positioning between early and late replication potentiate the landscape of chromosomal rearrangements in cancer.

genomics↗