bioRxiv Science⌕ Search

bioRxiv · 10.1101/676445

TET1 and TDG suppress intestinal tumorigenesis by down regulating the inflammatory and immune response pathways

Abstract

IntroductionAberrant DNA methylation is frequently observed in colorectal cancer (CRC), but the underlying mechanisms are poorly understood. Ten-Eleven Translocation (TET) dioxygenases and DNA repair enzyme Thymine DNA Glycosylase (TDG) are involved in active DNA demethylation by generating and removing, respectively, novel oxidized cytosine species. Mutations of TET1 and TDG, and alterations of the levels of oxidized cytosine species have been identified in human CRC cases, but the biological significance of the TET-TDG demethylation axis in intestinal tumorigenesis is unclear.\n\nMaterial and MethodsWe generated ApcMin mice with additional inactivation of Tet1 and/or Tdg, and characterized the methylome and transcriptome of intestinal adenomas by DREAM and RNA sequencing, respectively.\n\nResultsTet1- and/or Tdg-deficient ApcMin mice show enhanced intestinal tumorigenesis in comparison to wild type Tet1 and Tdg ApcMin mice. Specifically, Tet1 and/or Tdg-deficient ApcMin adenomas manifested increased size or features of erosion and stroma activation. Methylome analysis revealed progressive loss of global DNA hypomethylation in colonic adenomas from Tet1- and Tdg-deficient ApcMin mice, and hypermethylation of CpG islands in Tet1-deficient ApcMin mice. In addition, RNA sequencing showed upregulation of genes in inflammatory and immune response pathways in Tet1-and Tdg-mutant colonic adenomas compared to control ApcMin adenomas.\n\nConclusionsTaken together, these findings demonstrate the important role of active DNA demethylation mediated by TET-TDG in reducing intestinal tumor formation, by modulating the epigenome and inflammatory/immune responses. This study highlights a novel mechanism of epigenetic deregulation during intestinal tumorigenesis with diagnostic, therapeutic and prognostic implications.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tricarico, R., Madzo, J., Scher, G., Maegawa, S., Jelinek, J., Scher, C., Chang, W.-C., Nicolas, E., Zhou, Y., Slifker, M., Devarajan, K., Cai, K. Q., Nakajima, P., Xu, J., Mancuso, P., Doneddu, V., Bagella, L. M., Ingram, J., Balachandran, S., Peshkova, I., Koltsova, E., Grivennikov, S., Yen, T. J., Issa, J.-P., Bellacosa, A.. 2019-06-21. TET1 and TDG suppress intestinal tumorigenesis by down regulating the inflammatory and immune response pathways. https://doi.org/10.1101/676445

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

KEEP EXPLORING

Related preprints

BCL10 Gain-of-Function Impairs Germinal Center Participation by Naive B Cells and Cooperates with BCL6 to Drive Extrafollicular Diffuse Large B-Cell Lymphoma

BCL10 gain-of-function (GoF) mutations occur in diffuse large B-cell lymphoma (DLBCL) cases of the BN2/C1 molecular subgroup. These alterations activate CARD11-BCL10-MALT1 (CBM) signaling and drive resistance to multiple drug classes, but their role in disease pathogenesis is incompletely understood. In particular, interactions between BCL10 GoF and additional DLBCL oncogenes are undefined. Here, we show BCL10 GoF in naive B cells blocks their participation in germinal center (GC) reactions and permits transformation to DLBCL with a non-GC B-cell phenotype. Most clinical cases with BCL10 GoF also carry translocation of the BCL6 proto-oncogene, and we show that co-activation of these two lesions together promotes pronounced oncogenic synergy. Detailed single-cell analyses of underlying premalignant B-cell populations revealed expansion of extrafollicular memory B cells whose gene-expression program remains prominent in resulting lymphomas in both the mouse and corresponding human tumors. We therefore define a novel role for BCL10 activating mutations in enabling BCL6 lymphomagenesis.

cancer biology↗

Targeting NF-κB prevents Schwann cell reprogramming and plexiform neurofibroma initiation in mouse model of Nf1

Plexiform neurofibromas arise in approximately half of all individuals with Neurofibromatosis Type I (NF1). Genetic lesions apart from NF1 pathogenic variants are not present in NF1 mutant Schwann cells, suggesting that tumorigenesis may instead require cellular rewiring. To identify putatively re-wired tumor cells, we used multiplex imaging and flow cytometry to delineate markers that distinguish tumor Schwann cell from non-tumor Schwann cells. We identified tumor Schwann cells as CD44+;CD49f+ cells that show increased transcription of epithelial to mesenchymal plasticity (EMP)- associated genes. CD44+;CD49f+ expression was induced by treating Nf1-/- Schwann cells with stressors or by direct NF-{kappa}B pathway activation via IKK2; treated Schwann cells increased secretion of NF-{kappa}B targets and immune cell chemoattractants CCL2 and CCL3. In established tumors, MEK inhibition plus NF-{kappa}B blockade diminished tumor cell proliferation, tumor Schwann cells, immune cell populations, tumor cytokines and tumor number. Notably, transient single agent NF-{kappa}B pathway blockade was sufficient to significantly delay tumor formation in mice. Thus, Nf1 loss in Schwann cells is followed by NF-{kappa}B activation and cellular reprogramming that drives tumor initiation and targeting NF-{kappa}B activation can reduce NF1-deficient tumor formation.

cancer biology↗

Response to azacitidine and the TIM-3 inhibitor, sabatolimab, in MDS and CMML is associated with distinct immune and antigen-presentation states

Targeting the immune checkpoint TIM-3 is of interest in myeloid neoplasms, yet the hematopoietic and immune changes associated with anti-TIM-3 therapy remain poorly characterized. We used single-cell RNA sequencing to profile bone marrow (BM) and peripheral blood from patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) treated with the hypomethylating agent azacitidine combined with sabatolimab, a monoclonal antibody targeting TIM-3, and integrated Human Cell Atlas reference datasets for comparison. CITE-seq profiling showed that TIM-3 was predominantly expressed on dendritic cells and NK cells, with variable expression across other populations, including CD34 cells and CD8 T cells. At baseline, we identified a population of CD34 myeloid-biased progenitors specific to MDS/CMML samples ("HSPC-like") characterized by inflammatory gene expression programs and features of impaired differentiation. In MDS, elevated baseline HLA class II expression across hematopoietic stem and progenitor cells (HSPCs), HSPC-like cells, and multiple myeloid populations was associated with response. Consistent with this finding, trajectory analysis suggested that nonresponders bypassed HLA class II-high states during myeloid differentiation. In MDS, the presence of distinct CD8 T-cell populations and increased interferon-response programs in CD8 T and NK cells at baseline was also associated with response. In both MDS and CMML, treatment among responders was associated with contraction of BM CD8 and CD4 T-cell populations characterized by type I interferon-responsive and inflammatory programs, including IFIT1, IFIT2, and TNF, along with expansion of a distinct GZMH/IFITM1-expressing cytotoxic CD8 T-cell population. Together, these findings identify baseline antigen-presentation and immune-response programs associated with therapeutic response and reveal coordinated remodeling of myeloid and lymphoid compartments during azacitidine/sabatolimab treatment in MDS and CMML.

cancer biology↗