bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.04.15.718689

Mapping breast cancer lineage in radiation and immunotherapy using the REMAP mouse

Marshall, A. C.·Vahey, J.·Bagheri, M.·Saxe, R.·Fields, J.·Kolling, F. W.·McKenna, A.
View original source ↗Export metadata ↓

Abstract

We present REMAP (Recording Evolution in Mammary tumors via Active PyMT), a lineage-tracing mouse model that integrates inducible CRISPR recording with the MMTV-PyMT model of hormone receptor-positive (HR+) breast cancer. Inducible Cas9 drives editing of MARC1 homing guide RNAs (hgRNAs), generating heritable lineage marks, and enables reconstruction of clonal relationships. Using REMAP, we profiled tumor evolution and response to radiation combined with anti-PD1 immunotherapy. Treatment reduced tumor burden locally and systemically, and single-cell RNA sequencing revealed remodeling of the tumor microenvironment (TME). We identified metastatic clones present across primary tumors and distant sites, which exhibited elevated epithelial-mesenchymal transition (EMT) programs as a heritable clonal state. Treatment reduced EMT-associated transcriptional programs and reshaped immune composition, with radiation driving clonal expansion of T cells and reduced repertoire diversity. In contrast, cancer-associated fibroblast clones spanned multiple transcriptional states, indicating substantial stromal plasticity. Together, REMAP enables high-resolution coupling of clonal history and cellular state in vivo, revealing that tumor progression, metastasis, and therapeutic response are governed by heritable lineage programs.

Explore related subjects

cancer biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Marshall, A. C., Vahey, J., Bagheri, M., Saxe, R., Fields, J., Kolling, F. W., McKenna, A.. 2026-04-18. Mapping breast cancer lineage in radiation and immunotherapy using the REMAP mouse. https://doi.org/10.64898/2026.04.15.718689

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

mRNA-LNP vaccination induces microenvironment remodeling and generation of tissue-resident memory T cells in glioblastoma

Glioblastoma remains highly refractory to immunotherapy, in part because of a profoundly immunosuppressive tumour microenvironment that limits effective T-cell responses. Although mRNA vaccines can induce anti-tumour immunity, how they reshape the glioblastoma immune ecosystem to support durable tumour control is not well understood. Here we use an immunocompetent EGFRvIII-driven syngeneic glioblastoma model and antigen-specific mRNA lipid nanoparticle (mRNA-LNP) vaccination to define the cellular and spatial mechanisms underlying therapeutic response. In our model, vaccination induced durable EGFRvIII-specific humoral and cellular immunity, resulting in complete tumour eradication and long-term protection against intracranial rechallenge. Integrative analyses incorporating flow cytometry, tumour interstitial fluid profiling, multiplex immunostaining, spatial transcriptomics and ligand-receptor modelling demonstrated extensive remodelling of the tumour microenvironment following vaccination. Early tumour control was associated with expansion of pro-inflammatory and antigen-presenting myeloid populations, increased cytotoxic CD8 T-cell infiltration and activation, enhanced interferon-responsive signalling, and the formation of immune-supportive spatial niches enriched for antigen presentation and chemokine-mediated cellular communication. Vaccination promoted inflammatory chemokine relay networks centred on the CXCL16-CXCR6 axis, a pathway linked to tissue residency programming in the central nervous system. Functional depletion studies identified CD4 and CD8 T cells as essential mediators of therapeutic efficacy, while durable protection was maintained by tumour-specific brain-resident memory CD8 T cells that persisted despite peripheral lymphocyte depletion. Together, these findings identify T-cell-driven microenvironmental remodelling as a critical mechanism linking mRNA vaccination to the establishment of long-term brain-resident anti-tumour immunity in glioblastoma.

cancer biology↗
bioRxiv2026

Regulation of the Epstein-Barr Epigenome by Histone Variant MacroH2A

Histone variants play an important role in regulating chromatin dynamics of Epstein-Barr Virus (EBV). Here, we investigate the role of histone variant macroH2A in EBV chromatin structure, gene expression and copy number control during latent infection. ChIP-seq analysis in EBV+ SNU719 gastric carcinoma and Mutu I Burkitt lymphoma cells revealed that macroH2A was most enriched at repetitive DNA elements, including oriLyt, BHLF1, LF3 and terminal repeat (TR) regions of the EBV genome. MacroH2A depletion in EBV-associated gastric cancer cell line SNU719 led to a small increase in some viral lytic genes and increase in viral DNA copy number. RNAseq transcriptomics after macroH2A depletion identified major perturbations in cellular gene pathways, including beta-catenin/TCF signaling and chromatin remodeling. Depletion of macroH2A during EBV lytic reactivation reduced EBV lytic gene activation, but increased EBV DNA copy number. Previous study demonstrated a colocalization and cooperative binding between histone variant H2A.Z and EBNA1. We now show that depletion of macroH2A causes an increase in both H2A.Z and EBNA1 at oriP and cellular binding sites for EBNA1. We also found that gammaH2AX localizes to oriP and that this depends on macroH2A. Finally, we show that CRISPR/Cas9 knockout of macroH2A increases the replication and episome maintenance of oriP-containing plasmids. Taken together, these findings indicate that macroH2A localizes to the repetitive elements of EBV, including oriLyt, and can function to limit H2A.Z and EBNA1 binding at oriP, which alters DNA damage signaling at oriP and limits episomal replication. These findings provide a novel role for macroH2A in maintaining EBV copy number and genome integrity.

cancer biology↗
bioRxiv2026

Epigenomic circuits shaping cellular heterogeneity in pleural mesothelioma

Pleural mesothelioma (PM) is an aggressive and lethal malignancy with current treatments offering limited clinical benefit. In this study, we utilized single-cell chromatin accessibility and transcriptomic profiling of patient-matched samples to infer the epigenomic regulation underlying cellular heterogeneity in PM. High-resolution epigenomic profiling suggested transcriptional regulators with putative pro-tumoral roles in mesothelioma, whose function was experimentally tested using genetic perturbations across four PM cell lines. Furthermore, we observed several putative associations between epigenomic circuits and macrophage ontogeny, a sarcomatoid-like neoplastic state, and a fetal-like endothelial cell state. Our analysis also showed similarities between the chromatin accessibility landscapes of exhausted CD8 T and KLRC1 natural killer cells and identified NR4A2 as a potential shared regulator of dysfunction in both lymphocyte subsets. We further identified a state-specific distal enhancer near NR4A2 and experimentally validated its regulation of NR4A2 expression in Jurkat cells. Together, we provide an epigenomic map of PM and nominate candidate transcription factors and regulatory elements for future functional investigation, including their potential relevance to epigenetic editing strategies to limit tumor growth and enhance anti-tumor immunity.

cancer biology↗