Biology subjects

Roulois, D.

Publications and source records attributed to Roulois, D..

4 recordsLinked to original sources

bioRxiv2024

In vitro models to mimic tumor endothelial cell-mediated immune cell reprogramming in lung adenocarcinoma

Tumor endothelial (TECs) cells play a critical role in regulating immune responses within the tumor microenvironment (TME). However, the mechanisms by which TECs modulate immune cell population remain unclear, particularly in non-small cell lung cancer (NSCLC). Here, we investigated how NSCLC cells tweak normal endothelial cells (NECs) into TECs and the subsequent effects on immune regulation. NECs were cocultured with various NSCLC cell lines, using 2D and 3D coculture models to evaluate TEC-mediated effects on immune cells. We show that direct coculture led to significant transcriptomic, proteomic and kinomic alterations in TECs, especially in pro-inflammatory pathways. We identified a downregulation of the co-stimulatory molecule OX40L in TECs compared to NECs, suggesting impaired T-cell proliferation support. While TECs showed a limited effect on CD8+ T-cell activation, TECs supported CD4 T-cells polarization into Treg and Th22 subsets. Moreover, TECs also promoted M2-like macrophages polarization, thereby potentially contributing to the TME immunosuppression. State-of-the-art single-cell RNA sequencing of 3D multicellular tumor spheroids (MCTS) revealed distinct TEC subpopulations, including an inflammatory subset with UPR signature. The latter was absent in 2D-cultured NECs but present in freshly isolated and 2D-cultured TECs from NSCLC patients. Importantly, we also identified within MCTS a perivascular M2-like macrophage subset, predicted to interact with TECs with MIF and Midkine signaling. In conclusion, TECs in NSCLC tumors play a pivotal role in remodeling the TME immune landscape by promoting immune suppression. This study highlights the complex immunoregulatory functions of TECs within our different in vitro models that mimic aspects of the TME. Our data may provide new insights into potential therapeutic strategies targeting TECs or regulatory signaling to improve the efficacy of immunotherapy in NSCLC.

cancer biology↗

bioRxiv2023

Lymphoma B cells remodel bone marrow stromal cell organization and function to induce a supportive cancer-associated fibroblast network

Bone marrow (BM) involvement is a common feature of lymphomas deriving from germinal-center B cells and is associated with a bad prognosis. In particular, follicular lymphoma (FL) infiltrates the BM in 70% of cases, in association with a remodeling of surrounding tumor microenvironment. Analysis of in vitro-expanded FL mesenchymal stromal cells (MSCs) revealed an extensive alteration of BM stromal cell phenotypic, transcriptomic, and functional profiles. However, the mechanisms supporting the direct interplay between lymphoma B cells and their permissive stromal niche in situ have not been yet identified. In the current work, we identified in the BM milieu of FL patients a deregulation of soluble and extracellular matrix (ECM) components reflecting inflammation and ectopic differentiation into lymphoid-like stromal cells. We reproduced the same alterations in a murine model of lymphoma B-cell xenograft where a scRNAseq approach identified LepRpos MSCs as specifically and progressively reprogramed by tumor B-cell invasion. Analysis of FL BM collected before and after treatment confirmed that BM niche was partly dependent on the continuous contact with tumor B cells. Altogether, this work shed new lights on the kinetic and mechanisms of BM stromal niche reshaping in B-cell lymphoma.

cancer biology↗

bioRxiv2023

Core enhancers of the 3'RR optimize IgH nuclear position and loop conformation for oriented CSR

Class switch recombination is an essential process which enabling B cells to adapt immunoglobulin subtypes to antigens. Transcription plays a crucial role in regulating CSR in which the IgH 3Regulatory Region (3RR) was identified as a key player. The 3RR stands at the 3 end of IgH locus and is composed of four core enhancers surrounded by inverted repeated sequences, forming a quasi-palindrome. In addition to transcriptional control, nuclear organization appears to be an important level in CSR regulation. Furthermore, the chromatin loops at IgH locus facilitate an efficient CSR recombination by bringing the donor and acceptor switch regions closer together. However, the precise control mechanisms governing both of these processes remain partially understood. Here, using the reference DNA 3D-FISH technique combined with various high throughput approaches, we showed that 3RR core enhancers are necessary and sufficient to preorganize resting B cell nuclei to facilitate a deletional CSR mechanism at activated stage. We demonstrated that the 3RR core enhancers regulate IgH locus addressing in the nuclei, control IgH locus accessibility and orchestrate IgH loops formation. Our findings pinpointed an additional regulation level of mechanisms underlying B cell diversification. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/548507v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@69ca5aorg.highwire.dtl.DTLVardef@1640c29org.highwire.dtl.DTLVardef@15a7949org.highwire.dtl.DTLVardef@d0af7e_HPS_FORMAT_FIGEXP M_FIG C_FIG Position of IgH loci through B cell development (from transitional to stimulated stages) is represented by the red spots. In wt and c3RR context, IgH loci get closer from each other and from nucleus center during evolution from transitional to mature resting stage and they relocates more at nuclear periphery, away one from each other, upon in vitro stimulation. In{Delta} 3RR model, this dynamic is lost and, moreover, IgH loci are more localized to pericentromeric heterochromatin (represented by green area) since the mature resting B cell stage and remain in after in vitro stimulation.

immunology↗

bioRxiv2017

DNA-Demethylating Agents enhance cytolytic activity of CD8+ T Cells and anti-tumor immunity

Recent studies have shown that DNA methyltransferase inhibitors (DNMTi) can induce IRF7 activation and Type I/III interferon signaling through dsRNA-mediated viral mimicry in cancer cells. By performing a large pan-cancer analysis using TCGA data, we determined that IRF7 activation is associated with higher CD8+ T cell tumor infiltration and higher cytolytic activity across multiple cancer types. Accordingly, we demonstrate that DNMTi treatment results in increased CD8+ T cell tumor infiltration, enhanced cytolytic activity and CD8+ T cell dependent tumor growth inhibition. Finally, we show that DNMTi triggers a process marked by the induction of viral mimicry directly on CD8+ T cells, leading to activation of dsRNA sensing pathway, and up-regulation of T cell activation markers, effector cytokines, and Granzyme B. Taken together, our findings suggest that dsRNA sensing pathway activation in the immune compartment, through pharmacological DNA demethylation, is a viable strategy for boosting anti-tumor immune response.

cancer biology↗