Natasha Elise Weiser

All Publications

• A Guide to Extrachromosomal DNA: Cancer's Dynamic Circular Genome. Cancer discovery Weiser, N. E., Watkins, T. B., Chang, H. Y., Mischel, P. S. 2025: OF1-OF10

  Abstract

  Focal amplifications on ecDNAs are commonly found in cancer and are associated with poor patient outcomes and distinct biology. In this review, we provide a guide to ecDNA biology and available tools as well as our perspective on this rapidly evolving field.

  View details for DOI 10.1158/2159-8290.CD-25-0230

  View details for PubMedID 40287855

• Unified molecular approach for spatial epigenome, transcriptome, and cell lineages. Proceedings of the National Academy of Sciences of the United States of America Huang, Y. H., Belk, J. A., Zhang, R., Weiser, N. E., Chiang, Z., Jones, M. G., Mischel, P. S., Buenrostro, J. D., Chang, H. Y. 2025; 122 (16): e2424070122

  Abstract

  Spatial epigenomics and multiomics can provide fine-grained insights into cellular states but their widespread adoption is limited by the requirement for bespoke slides and capture chemistries for each data modality. Here, we present SPatial assay for Accessible chromatin, Cell lineages, and gene Expression with sequencing (SPACE-seq), a method that utilizes polyadenine-tailed epigenomic libraries to enable facile spatial multiomics using standard whole transcriptome reagents. Applying SPACE-seq to a human glioblastoma specimen, we reveal the state of the tumor microenvironment, extrachromosomal DNA copy numbers, and identify putative mitochondrial DNA variants.

  View details for DOI 10.1073/pnas.2424070122

  View details for PubMedID 40249782

• Enhancing transcription-replication conflict targets ecDNA-positive cancers. Nature Tang, J., Weiser, N. E., Wang, G., Chowdhry, S., Curtis, E. J., Zhao, Y., Wong, I. T., Marinov, G. K., Li, R., Hanoian, P., Tse, E., Mojica, S. G., Hansen, R., Plum, J., Steffy, A., Milutinovic, S., Meyer, S. T., Luebeck, J., Wang, Y., Zhang, S., Altemose, N., Curtis, C., Greenleaf, W. J., Bafna, V., Benkovic, S. J., Pinkerton, A. B., Kasibhatla, S., Hassig, C. A., Mischel, P. S., Chang, H. Y. 2024; 635 (8037): 210-218

  Abstract

  Extrachromosomal DNA (ecDNA) presents a major challenge for cancer patients. ecDNA renders tumours treatment resistant by facilitating massive oncogene transcription and rapid genome evolution, contributing to poor patient survival1-7. At present, there are no ecDNA-specific treatments. Here we show that enhancing transcription-replication conflict enables targeted elimination of ecDNA-containing cancers. Stepwise analyses of ecDNA transcription reveal pervasive RNA transcription and associated single-stranded DNA, leading to excessive transcription-replication conflicts and replication stress compared with chromosomal loci. Nucleotide incorporation on ecDNA is markedly slower, and replication stress is significantly higher in ecDNA-containing tumours regardless of cancer type or oncogene cargo. pRPA2-S33, a mediator of DNA damage repair that binds single-stranded DNA, shows elevated localization on ecDNA in a transcription-dependent manner, along with increased DNA double strand breaks, and activation of the S-phase checkpoint kinase, CHK1. Genetic or pharmacological CHK1 inhibition causes extensive and preferential tumour cell death in ecDNA-containing tumours. We advance a highly selective, potent and bioavailable oral CHK1 inhibitor, BBI-2779, that preferentially kills ecDNA-containing tumour cells. In a gastric cancer model containing FGFR2 amplified on ecDNA, BBI-2779 suppresses tumour growth and prevents ecDNA-mediated acquired resistance to the pan-FGFR inhibitor infigratinib, resulting in potent and sustained tumour regression in mice. Transcription-replication conflict emerges as a target for ecDNA-directed therapy, exploiting a synthetic lethality of excess to treat cancer.

  View details for DOI 10.1038/s41586-024-07802-5

  View details for PubMedID 39506153

• Origins and impact of extrachromosomal DNA. Nature Bailey, C., Pich, O., Thol, K., Watkins, T. B., Luebeck, J., Rowan, A., Stavrou, G., Weiser, N. E., Dameracharla, B., Bentham, R., Lu, W., Kittel, J., Yang, S. Y., Howitt, B. E., Sharma, N., Litovchenko, M., Salgado, R., Hung, K. L., Cornish, A. J., Moore, D. A., Houlston, R. S., Bafna, V., Chang, H. Y., Nik-Zainal, S., Kanu, N., McGranahan, N., Genomics England Consortium, Flanagan, A. M., Mischel, P. S., Jamal-Hanjani, M., Swanton, C., Ambrose, J. C., Arumugam, P., Bevers, R., Bleda, M., Boardman-Pretty, F., Boustred, C. R., Brittain, H., Brown, M. A., Caulfield, M. J., Chan, G. C., Giess, A., Griffin, J. N., Hamblin, A., Henderson, S., Hubbard, T. J., Jackson, R., Jones, L. J., Kasperaviciute, D., Kayikci, M., Kousathanas, A., Lahnstein, L., Lakey, A., Leigh, S. E., Leong, I. U., Lopez, F. J., Maleady-Crowe, F., McEntagart, M., Minneci, F., Mitchell, J., Moutsianas, L., Mueller, M., Murugaesu, N., Need, A. C., O'Donovan, P., Odhams, C. A., Patch, C., Perez-Gil, D., Pereira, M. B., Pullinger, J., Rahim, T., Rendon, A., Rogers, T., Savage, K., Sawant, K., Scott, R. H., Siddiq, A., Sieghart, A., Smith, S. C., Sosinsky, A., Stuckey, A., Tanguy, M., Taylor Tavares, A. L., Thomas, E. R., Thompson, S. R., Tucci, A., Welland, M. J., Williams, E., Witkowska, K., Wood, S. M., Zarowiecki, M. 2024; 635 (8037): 193-200

  Abstract

  Extrachromosomal DNA (ecDNA) is a major contributor to treatment resistance and poor outcome for patients with cancer1,2. Here we examine the diversity of ecDNA elements across cancer, revealing the associated tissue, genetic and mutational contexts. By analysing data from 14,778 patients with39 tumour types from the 100,000 Genomes Project, we demonstrate that 17.1% of tumour samples contain ecDNA. We reveal a pattern highly indicative of tissue-context-based selection for ecDNAs, linking their genomic content to their tissue of origin. We show that not only is ecDNA a mechanism for amplification of driver oncogenes, but it alsoa mechanism that frequently amplifies immunomodulatory and inflammatory genes, such as those that modulate lymphocyte-mediated immunity and immune effector processes. Moreover, ecDNAs carrying immunomodulatory genes are associated with reduced tumour T cell infiltration. We identify ecDNAs bearing only enhancers, promoters and lncRNA elements, suggesting the combinatorial power of interactions between ecDNAs in trans. We alsoidentify intrinsic and environmental mutational processes linked to ecDNA, including those linked to its formation, such as tobacco exposure, and progression, such as homologous recombination repair deficiency. Clinically, ecDNA detection was associated with tumour stage, more prevalent after targeted therapy and cytotoxic treatments, and associated with metastases and shorter overall survival. These results shed light on why ecDNA is a substantial clinical problem that can cooperatively drive tumour growth signals, alter transcriptional landscapes and suppress the immune system.

  View details for DOI 10.1038/s41586-024-08107-3

  View details for PubMedID 39506150

• Enhancer activation from transposable elements in extrachromosomal DNA. bioRxiv : the preprint server for biology Kraft, K., Murphy, S. E., Jones, M. G., Shi, Q., Bhargava-Shah, A., Luong, C., Hung, K. L., He, B. J., Li, R., Park, S. K., Weiser, N. E., Luebeck, J., Bafna, V., Boeke, J. D., Mischel, P. S., Boettiger, A. N., Chang, H. Y. 2024

  Abstract

  Extrachromosomal DNA (ecDNA) is a hallmark of aggressive cancer, contributing to both oncogene amplification and tumor heterogeneity. Here, we used Hi-C, super-resolution imaging, and long-read sequencing to explore the nuclear architecture of MYC-amplified ecDNA in colorectal cancer cells. Intriguingly, we observed frequent spatial proximity between ecDNA and 68 repetitive elements which we called ecDNA-interacting elements or EIEs. To characterize a potential regulatory role of EIEs, we focused on a fragment of the L1M4a1#LINE/L1 which we found to be co-amplified with MYC on ecDNA, gaining enhancer-associated chromatin marks in contrast to its normally silenced state. This EIE, in particular, existed as a naturally occurring structural variant upstream of MYC, gaining oncogenic potential in the transcriptionally permissive ecDNA environment. This EIE sequence is sufficient to enhance MYC expression and is required for cancer cell fitness. These findings suggest that silent repetitive genomic elements can be reactivated on ecDNA, leading to functional cooption and amplification. Repeat element activation on ecDNA represents a mechanism of accelerated evolution and tumor heterogeneity and may have diagnostic and therapeutic potential.

  View details for DOI 10.1101/2024.09.04.611262

  View details for PubMedID 39282372

  View details for PubMedCentralID PMC11398463

• Targeted profiling of human extrachromosomal DNA by CRISPR-CATCH. Nature genetics Hung, K. L., Luebeck, J., Dehkordi, S. R., Colon, C. I., Li, R., Wong, I. T., Coruh, C., Dharanipragada, P., Lomeli, S. H., Weiser, N. E., Moriceau, G., Zhang, X., Bailey, C., Houlahan, K. E., Yang, W., Gonzalez, R. C., Swanton, C., Curtis, C., Jamal-Hanjani, M., Henssen, A. G., Law, J. A., Greenleaf, W. J., Lo, R. S., Mischel, P. S., Bafna, V., Chang, H. Y. 2022

  Abstract

  Extrachromosomal DNA (ecDNA) is a common mode of oncogene amplification but is challenging to analyze. Here, we adapt CRISPR-CATCH, in vitro CRISPR-Cas9 treatment and pulsed field gel electrophoresis of agarose-entrapped genomic DNA, previously developed for bacterial chromosome segments, to isolate megabase-sized human ecDNAs. We demonstrate strong enrichment of ecDNA molecules containing EGFR, FGFR2 and MYC from human cancer cells and NRAS ecDNA from human metastatic melanoma with acquired therapeutic resistance. Targeted enrichment of ecDNA versus chromosomal DNA enabled phasing of genetic variants, identified the presence of an EGFRvIII mutation exclusively on ecDNAs and supported an excision model of ecDNA genesis in a glioblastoma model. CRISPR-CATCH followed by nanopore sequencing enabled single-molecule ecDNA methylation profiling and revealed hypomethylation of the EGFR promoter on ecDNAs. We distinguished heterogeneous ecDNA species within the same sample by size and sequence with base-pair resolution and discovered functionally specialized ecDNAs that amplify select enhancers or oncogene-coding sequences.

  View details for DOI 10.1038/s41588-022-01190-0

  View details for PubMedID 36253572

• Oncogene Convergence in Extrachromosomal DNA Hubs. Cancer discovery Weiser, N. E., Hung, K. L., Chang, H. Y. 2022: OF1-OF4

  Abstract

  Extrachromosomal DNA circles (ecDNA) are a common mechanism for oncogene amplification and are associated with worse clinical outcomes compared with other types of oncogene amplification. Several recent discoveries of ecDNA hubs-local congregations of ecDNAs in the nucleus-highlight unique features of ecDNA biology that may contribute to higher oncogene expression and rapid tumor evolution.

  View details for DOI 10.1158/2159-8290.CD-22-0076

  View details for PubMedID 35398879

• ecDNA hubs drive cooperative intermolecular oncogene expression. Nature Hung, K. L., Yost, K. E., Xie, L., Shi, Q., Helmsauer, K., Luebeck, J., Schopflin, R., Lange, J. T., Chamorro Gonzalez, R., Weiser, N. E., Chen, C., Valieva, M. E., Wong, I. T., Wu, S., Dehkordi, S. R., Duffy, C. V., Kraft, K., Tang, J., Belk, J. A., Rose, J. C., Corces, M. R., Granja, J. M., Li, R., Rajkumar, U., Friedlein, J., Bagchi, A., Satpathy, A. T., Tjian, R., Mundlos, S., Bafna, V., Henssen, A. G., Mischel, P. S., Liu, Z., Chang, H. Y. 2021

  Abstract

  Extrachromosomal DNA (ecDNA) is prevalent in human cancers and mediates high expression of oncogenes through gene amplification and altered gene regulation1. Gene induction typically involves cis-regulatory elements that contact and activate genes on the same chromosome2,3. Here we show that ecDNA hubs-clusters of around 10-100 ecDNAs within the nucleus-enable intermolecular enhancer-gene interactions to promote oncogene overexpression. ecDNAs that encode multiple distinct oncogenes form hubs in diverse cancer cell types and primary tumours. Each ecDNA is more likely to transcribe the oncogene when spatially clustered with additional ecDNAs. ecDNA hubs are tethered by the bromodomain and extraterminal domain (BET) protein BRD4 in a MYC-amplified colorectal cancer cell line. The BET inhibitor JQ1 disperses ecDNA hubs and preferentially inhibits ecDNA-derived-oncogene transcription. The BRD4-bound PVT1 promoter is ectopically fused to MYC and duplicated in ecDNA, receiving promiscuous enhancer input to drive potent expression of MYC. Furthermore, the PVT1 promoter on an exogenous episome suffices to mediate gene activation in trans by ecDNA hubs in a JQ1-sensitive manner. Systematic silencing of ecDNA enhancers by CRISPR interference reveals intermolecular enhancer-gene activation among multiple oncogene loci that are amplified on distinct ecDNAs. Thus, protein-tethered ecDNA hubs enable intermolecular transcriptional regulation and may serve as units of oncogene function and cooperative evolution and as potential targets for cancer therapy.

  View details for DOI 10.1038/s41586-021-04116-8

  View details for PubMedID 34819668