Biology subjects

Le Dily, F.

Publications and source records attributed to Le Dily, F..

12 recordsLinked to original sources

bioRxiv2025

Chromatin landscape of endometrial tumor cells of tamoxifen users is associated with loss of progestin regulation

Tamoxifen is an effective steroid estrogen receptor modulator (SERM) widely used in breast cancer treatment. It acts through competitive inhibition of natural ligand estrogen (E2) at the estrogen receptor (ER), affecting ER interactions with other nuclear receptors, chromatin modulators, genomic structural proteins and co-regulators. Although tamoxifen inhibits the progression of breast cancer, it increases the risk of endometrial cancer, particularly in postmenopausal women. Progesterone receptor (PR) and ER cistromes of endometrial adenocarcinoma Ishikawa cells treated with ovarian hormones showed that ER binding sites are shared by PR at open sites of chromatin. This could explain, in part, progestin regulation of estrogen effects on ER/PR positive endometrial cancer cells. Here, we compared ER cistromes from endometrial tumors of tamoxifen users and non-users with ER and PR cistromes from Ishikawal model to evaluate how SERM exposure affects ER-binding signature. Non-user ER cistrome is closer to R5020-treated Ishikawa PR cistrome, while tamoxifen users ER cistrome is similar to estradiol-treated Ishikawa ER cistrome. The subset of ERbs of non-users regulates inflammatory signaling pathway genes. In contrast, the subset of ERbs of tamoxifen users modulates early estrogen response pathway genes, such as the oncogene NRIP1. This suggests that exposure to tamoxifen redirects ER binding toward genomic regions typically responsive to estrogen, whereas ER binding in non-users retains features associated with PR-occupied regulatory sites. These results provide an example of how SERM treatment may remodel endometrial tumor epigenetic landscape, highlighting context-dependent genomic responses that should be considered to prevent deregulation of endometrial tissue under tamoxifen exposure.

cancer biology↗

bioRxiv2025

EWS-FLI1 Expression in Human Embryonic MSCs Leads to Transcriptional Reprograming, Defective DNA Damage Repair and Ewing Sarcoma

Ewing sarcoma (ES) is an aggressive bone and soft tissue neoplasm characterized by EWSR1/ETS rearrangements and whose cellular origin remains unclear. EWS-FLI1 expression in human pediatric mesenchymal stem cells (hpMSCs) induces a quantitatively and qualitatively different transcriptional response than its expression in human adult MSCs (haMSCs), but fails to form tumors in vivo. ES cells have early developmental lineage signatures distinct from postnatal MSCs. Here, we have generated MSCs from experimental teratomas out of human embryonic stem cells (heSCs). Transduction of these human embryonic mesenchymal stem cells (heMSCs) with EWS-FLI1 results in the acquisition of an ES transcriptome, although the oncogene does not preferentially bind to promoters, but to intronic and intergenic microsatellites with >10 CA dinucleotides and GGAA repeats, respectively. In heMSCs, EWS-FLI1 directly regulates BRCA1 expression, although EWS-FLI1-expressing cells show defects in DNA damage repair. Xenografting of EWS-FLI1-transduced heMSCs resulted in the formation of tumors expressing characteristic ES markers. In summary, EWS-FLI1 enforces an aberrant transcriptome and endows in vivo transforming capacity when expressed in an undifferentiated early heMSC. Our approach represents an innovative experimental method for understanding critical aspects of the biology of developmental tumors, from leukemia to sarcomas, in which few (even single) genetic alterations are able to transform a fetal stem cell.

cancer biology↗

bioRxiv2023

The Hippo kinase LATS1 controls CTCF chromatin occupancy and the hormonal response of three-dimensionally grown breast cancer cells

The cancer epigenome has been studied in cells cultured in 2D monolayers on plastic surfaces, but recent studies highlight the impact of the extracellular matrix (ECM) and the 3D environment on multiple cellular functions. Here, we report the physical, biochemical and genomic differences between T47D breast cancer cells cultured in 2D monolayer and as 3D spheroids in Matrigel. Cells within 3D spheroids exhibit a rounder nucleus with less accessible, more compacted chromatin, and altered expression of over 2,000 genes, the majority of which become repressed. Hi-C analysis reveals that cells grown in 3D exhibit enrichment in regions belonging to the B compartment, decrease on chromatin bound CTCF and increased fusion of Topologically Associating Domains (TADs). Upregulation of the Hippo pathway in 3D spheroids results in the activation of the LATS1 kinase, which promotes phosphorylation and displacement of CTCF from DNA, likely responsible for the observed TAD fusions. Cells grown in 3D exhibit higher progesterone receptor (PR) binding to chromatin, leading to an increase in the number hormone-regulated genes. This effect is in part mediated by the LATS1 activation, which favors cytoplasmic retention of YAP and CTCF removal.

genomics↗

bioRxiv2022

Quantitative analysis of cellular morphology during in vitro decidualization

Decidualization is a differentiation process involving shape reorganization from a fibroblast to an epithelioid-like appearance of endometrial stromal cells. Specificities of these cells impede the use of existing automated tools to follow morphological changes during differentiation; we therefore developed a simple but accurate methodology to quantify the phenotypical changes that occur in an in vitro decidualization system. The approach consists of the analysis of the circularity of the cells directly from light microscopy images. Here, we used this methodology to follow the effects of progesterone or progestin R5020 in combination with estradiol (E2) and cAMP on inducing the decidualization of human endometrial cells. We further implemented a statistical model to detect the differences in the kinetics of decidualization of the two hormonal stimuli before all the cell population acquired the decidual phenotype. We found that 2 days after stimulation are sufficient to detect statistical differences in morphology between decidualization induced and control cells. Here, we detail the model and scripts in order to provide a useful, practical and low cost tool to evaluate morphological aspects of endometrial stromal differentiation. Availability and implementationSee supplementary methods Supplementary informationSupplementary data is available online.

bioinformatics↗

bioRxiv2021

Profiling of histone H1 variants and changes on genome architecture and gene expression upon histone H1 depletion in breast cancer cells

Up to seven members of the histone H1 family may contribute to chromatin compaction and its regulation in human somatic cells. In breast cancer cells, knock-down of multiple H1 variants deregulates many genes, promotes the appearance of genome-wide accessibility sites and triggers an interferon response via activation of heterochromatic repeats. However, how these changes in the expression profile relate to the re-distribution of H1 variants as well as to genome conformational changes have not been yet studied. Here, we combined ChIP-seq of five endogenous H1 variants with Chromosome Conformation Capture analysis in wild-type and H1 knock-down T47D cells. The results indicate that H1 variants coexist in the genome in two large groups depending on the local DNA GC content and that their distribution is robust with respect to multiple H1 depletion. Despite the small changes in H1 variants distribution, knock-down of H1 translated into more isolated but de-compacted chromatin structures at the scale of Topologically Associating Domains or TADs. Such changes in TAD structure correlated with a coordinated gene expression response of their resident genes. This is the first report describing simultaneous profiling of five endogenous H1 variants within a cell line and giving functional evidence of genome topology alterations upon H1 depletion in human cancer cells.

genomics↗

bioRxiv2020

STAG2 loss-of-function affects short-range genomic contacts and modulates urothelial differentiation in bladder cancer cells

Cohesin exists in two variants, containing either STAG1 or STAG2. STAG2 is one of the most commonly mutated genes in human cancer, and a major bladder cancer tumor suppressor. Little is known about how its inactivation contributes to tumor development. Here, we analyze the genomic distribution of STAG1 and STAG2 and perform STAG2 loss-of-function experiments using RT112 bladder cancer cells; we then analyze the resulting genomic effects by integrating gene expression and chromatin interaction data. Cohesin-STAG2 is required for DNA contacts within topological domains, but not for compartment maintenance of domain boundary integrity. Cohesin-STAG2-mediated interactions are short-ranged and engage promoters and gene bodies with higher frequency than those mediated by cohesin-STAG1. STAG2 knockdown resulted in a modest but consistent down-regulation of the luminal urothelial differentiation signature, mirroring differences between STAG2-high and STAG2-low bladder tumors. Both lost and gained contacts were enriched among STAG1/STAG2 common sites as well as STAG2-enriched sites. Contacts lost upon depletion of STAG2 were significantly assortative, indicating their proximity at the 3D level, and were associated with changes in gene expression. Overall, our findings indicate that, in urothelial cells, STAG2 is required for the establishment and/or maintenance of DNA looping that, in turn, sustains the luminal differentiation program. This mechanism may contribute to the tumor suppressor function of STAG2 in bladder cancer.

cancer biology↗

bioRxiv2019

Higher-order chromatin organization defines PR and PAX2 binding to regulate endometrial cancer cell gene expression

Estrogen (E2) and Progesterone (Pg), via their specific receptors (ER and PR respectively), are major determinants in the development and progression of endometrial malignancies. Here, we have studied how E2 and the synthetic progestin R5020 affect genomic functions in Ishikawa endometrial cancer cells. Using ChIPseq in cells exposed to the corresponding hormones, we identified cell specific binding sites for ER (ERbs) and PR (PRbs), which mostly correspond to independent sites but both adjacent to sites bound by PAX2. Analysis of long-range interactions by Hi-C showed enrichment of regions co-bound by PR and PAX2 inside TADs that contain differentially progestin-regulated genes. These regions, which we call "progestin control regions" (PgCRs), exhibit an open chromatin state prior to the exposure to the hormone. Our observations suggest that endometrial response to progestins in differentiated endometrial tumor cells results in part from binding of PR together with partner transcription factors to PgCRs, compartmentalizing hormone-independent open chromatin.

genomics↗

bioRxiv2017

Hormone Control Regions mediate opposing steroid receptor-dependent genome organizations

In breast cancer cells, topologically associating domains (TADs) behave as units of hormonal gene regulation with transcripts within hormone responsive TADs changing coordinately their expression in response to steroid hormones. Here we further described that responsive TADs contain 20-100 kb-long clusters of intermingled estrogen receptor (ER) and progesterone receptor (PR) binding sites, hereafter called Hormone-Control Regions (HCRs). We identified more than 200 HCRs, which are frequently bound by ER and PR even in the absence of hormones. These HCRs establish steady long-distance inter-TAD interactions between them and organize characteristic looping structures with promoters even in the absence of hormones. This organization is dependent on the expression of the receptors and is further dynamically modulated in response to steroid hormones. HCRs function as platforms integrating different signals resulting in some cases in opposite transcriptional responses to estrogens or progestins. Altogether, these results suggest that steroid hormone receptors act not only as hormone-regulated sequence-specific transcription factors, but also as local and global genome organizers.\n\nHighlightsHormone responsive TADs are organized around conserved large regulatory regions (HCRs) enriched in ER and PR.\nHCR contact promoters within their TADs and engaged long-range inter-TADs contacts between them.\nBinding of the receptors in absence of hormones maintains global HCR-HCR interactions and intra-TADs regulatory loops.\nHCRs can integrate the hormone signals in divergent ways leading to opposite restructuration of TADs in response to Estrogens or Progestins.

genomics↗

bioRxiv2017

Deimination of arginine at the C-terminal domain favors RNA polymerase II pause release

HighlightsO_LIPeptidyl arginine deiminase 2 (PADI2) citrullinates arginine1810 (cit1810) present at carboxy-terminal domain of RNA polymerase II (RNAP2-CTD).\nC_LIO_LIPADI2 and R1810 of RNAP2-CTD regulate transcription and proliferation of breast cancer cells.\nC_LIO_LIAbsence of cit1810 at RNAP2-CTD leads to RNAP2 accumulation at proximal promoter regions.\nC_LIO_LICit1810 at RNAP2-CTD facilitate interaction with P-TFEb complex.\nC_LI\n\nSUMMARYThe post-translational modification of key residues at the carboxy-terminal domain of RNA polymerase II (RNAP2-CTD), coordinates transcription, splicing, and RNA processing by modulating its capacity to act as a landing platform for a variety of protein complexes. Here, we identify a new modification at the CTD, the deimination of arginine and its conversion to citrulline by peptidyl arginine deiminase 2 (PADI2), an enzyme that has been associated with several diseases including cancer. We show that among PADI family members, only PADI2 citrullinates R1810 (Cit1810) at repeat 31 of the CTD. Depletion of PADI2 or loss of R1810 result in accumulation of RNAP2 at transcription start sites, reduced gene expression and inhibition of cell proliferation. Cit1810 is needed for interaction with the P-TEFb (positive transcription elongation factor b) kinase complex and for its recruitment to chromatin. In this way, CTD-Cit1810 favors RNAP2 pause release and efficient transcription in breast cancer cells.

cancer biology↗

bioRxiv2017

Progesterone receptor maintains estrogen receptor gene expression by regulating DNA methylation in hormone-free breast cancer cells

Breast cancer prognosis and response to endocrine therapy strongly depends on the expression of the estrogen and progesterone receptors (ER and PR, respectively). Although much is known about ER gene (ESR1) regulation after hormonal stimulation, how it is regulated in hormone-free condition is not fully understood. We used ER-/PR-positive breast cancer cells to investigate the role of PR in ESR1 regulation in the absence of hormones. We show that PR binds to the low-methylated ESR1 promoter and maintains both gene expression and DNA methylation of the ESR1 locus in hormone-deprived breast cancer cells. Depletion of PR reduces ESR1 expression, with a concomitant increase in gene promoter methylation. The high amount of methylation in the ESR1 promoter of PR-depleted cells persists after the stable re-expression of PR and inhibits PR binding to this genomic region. As a consequence, the rescue of PR expression in PR-depleted cells is insufficient to restore ESR1 expression. Consistently, DNA methylation impedes PR binding to consensus progesterone responsive elements. These findings contribute to understanding the complex crosstalk between PR and ER and suggest that the analysis of ESR1 promoter methylation in breast cancer cells can help to design more appropriate targeted therapies for breast cancer patients.

molecular biology↗

bioRxiv2017

Distinct roles of cohesin-SA1 and cohesin-SA2 in 3D chromosome organization

In addition to mediating sister chromatid cohesion, cohesin plays a central role in DNA looping and segmentation of the genome into contact domains (TADs). Two variant cohesin complexes that contain either STAG/SA1 or SA2 are present in all cell types. Here we addressed their specific contribution to genome architecture in non-transformed human cells. We found that cohesin-SA1 drives stacking of cohesin rings at CTCF-bound sites and thereby contributes to the stabilization and preservation of TAD boundaries. In contrast, a more dynamic cohesin-SA2 promotes cell type-specific contacts between enhancers and promoters within TADs independently of CTCF. SA2 loss, a condition frequently observed in cancer cells, results in increased intra-TAD interactions, likely altering the expression of key cell identity genes.

genomics↗

bioRxiv2017

Managing The Analysis Of High-Throughput Sequencing Data

T47D_rep2 and b1913e6c1_51720e9cf were two Hi-C samples. They were born and processed at the same time, yet their fates were very different. The life of b1913e6c1_51720e9cf was simple and fruitful, while that of T47D_rep2 was full of accidents and sorrow. At the heart of these differences lies the fact that b1913e6c1_51720e9cf was born under a lab culture of Documentation, Automation, Traceability, Autonomy and compliance with the FAIR Principles. Their lives are a lesson for those who wish to embark on the journey of managing high throughput sequencing data.

bioinformatics↗