Biology subjects

Bennaceur-Griscelli, A.

Publications and source records attributed to Bennaceur-Griscelli, A..

6 recordsLinked to original sources

bioRxiv2023

BCR-ABL promotes hematopoietic stem and progenitor cell formation in embryonic stem cells

Generating Hematopoietic Stem Cells (HSCs) from Pluripotent Stem Cells (PSCs) has been a long-lasting quest in the field of hematopoiesis. Previous studies suggested that enforced expression of BCR-ABL, the unique oncogenic driver of Chronic Myelogeneous Leukemia (CML), in Embryonic Stem Cells (ESCs)-derived hematopoietic cells is sufficient to confer long-term in vivo repopulating potential. To precisely uncover the molecular events regulated by the Tyrosine-kinase activity of BCR-ABL1 (p210) during the course of hematopoietic differentiation, we engineered a Tet-ON inducible system to modulate its expression in murine ESC. We showed in unique site-directed knock-in ESC model, that BCR-ABL expression tightly regulated by doxycycline (dox) controls the formation and the maintenance of immature hematopoietic progenitors. Interestingly, these progenitors can be expanded in vitro for several passages in the presence of dox. Our analysis of cell surface markers and transcriptome compared to wild-type fetal and adult HSCs unraveled a similar molecular signature. LTC-IC assay confirmed their self-renewal capacities albeit with a differentiation bias towards erythroid and myeloid cells. Collectively, our novel Tet-ON system represents a unique in vitro model to shed lights on ESC-derived hematopoiesis, CML initiation and maintenance. KEY POINTSO_LIWe report a unique BCR-ABL-induced-embryonic stem cell -derived hematopoiesis model in murine embryonic stem cells C_LIO_LIThis BCR-ABL-induced self-renewal and differentiation model can be of major interest to uncover molecular events required for ESC-derived hematopoiesis C_LI

cancer biology↗

bioRxiv2022

Modeling Global Genomic Instability in Chronic Myeloid Leukemia (CML) using patient-derived induced pluripotent stem cells (iPSC)

Using induced Pluripotent Stem Cell (iPSC) technology, it is now possible to reprogram the primary leukemic cells to pluripotency and generate a major source of stem cells. To determine the feasibility of modeling global genomic instability characterizing chronic myeloid leukemia (CML) progression towards blast crisis (BC), we have used a patient-specific iPSC line that has been submitted to in vitro mutagenesis with the mutagenic agent N-ethyl-N-nitrosourea (ENU). Increased genomic instability was validated using g-H2AX and micronuclei assays. As compared to non-mutagenized cultures, these iPSC generated an increased numbers of progenitors (x 5-Fold) which proliferated in liquid cultures with a blast cell morphology. CGH array analyses were performed using ENU-treated iPSC-derived hematopoietic cells in two different time points as compared to leukemic iPSC cultured without ENU. Several cancer genes were found to be involved in the ENU-treated cultures, some known to be altered in leukemia (BLM, IKZF1, NCOA2, ALK, EP300, ERG, MKL1, PHF6 and TET1). Remarkably, transcriptome geodataset GSE4170 (Radich et al., 2006) allowed us to associate 125 of 249 of the aberrations that we detected in CML iPSC, with genes already described during progression of CML to BC (p-value =9.43exp32, after ANOVA with 1000 permutations). 38 most predictive aberrations allowed perfect reclassification of BC and chronic phase samples by unsupervised classification. Among these candidates, eleven of them have been described in CML physiopathology and connected to tyrosine kinase inhibitor (TKI) resistance and genomic instability. Overall, these results demonstrated that we have generated for the first time to our knowledge, an in vitro genetic instability model in CML, reproducing genomic events described in patients with BC. This tool using patient-derived iPSC could be of interest to study CML progression, to discover novel targets and eventually to test novel therapies.

cancer biology↗

bioRxiv2021

ENOX2 NADH Oxidase: A BCR-ABL1-dependent cell surface and secreted redox protein in chronic myeloid leukemia (CML)

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm caused by the acquisition of BCR-ABL1 fusion in a hematopoietic stem cell. We identified the ENOX2 gene as up-regulated in BCR-ABL1-expressing UT-7 cell lines through a transcriptome assay. The oncofoetal ENOX2 protein (Ecto-Nicotinamide Adenine Dinucleotide Oxidase Disulfide Thiol Exchanger 2) is expressed on the external plasma membrane surface of cancer cells and can be released in cancer patients serum. Considering these data, we studied ENOX2 expression in CML cell lines and patients using quantitative RT-PCR, western-blots, the ELISA method, and transcriptomic dataset reanalysis. We confirmed increased ENOX2 mRNA expression in the BCR-ABL1-expressing UT-7 cell line. Comparable results were obtained in CML patients at diagnosis. Western-blot analyses on UT-7 and TET-inducible Ba/F3 cell lines established the up-regulation of ENOX2 protein. BCR-ABL1 has been found to induce ENOX2 overexpression in a kinase-dependent manner. In a series of 41 patients with CML, ELISA assays showed a highly significant increase of ENOX2 protein levels in the plasma of patients with CML (p < 0.0001) as compared to controls (n=28). Transcriptomic dataset (GSE4170) reanalyzes have shown specific ENOX2 mRNA overexpression in the chronic phase of the disease. Bioinformatic analyses identified several genes whose mRNA expression was positively correlated to ENOX2. Some of them encode proteins involved in cellular functions compatible with the growth deregulation observed in CML. All in all, our results demonstrate for the first time the upregulation of a secreted Redox protein in a BCR-ABL1-dependent manner in CML. Our data suggest that ENOX2 (through its transcriptional program) plays a significant role in the BCR-ABL1 leukemogenesis. Further studies are required to clarify the relationship between BCR-ABL1 and ENOX2.

cancer biology↗

bioRxiv2021

Detection of hematopoietic stem cell transcriptome in human fetal kidneys and kidney organoids derived from human induced pluripotent stem cells (iPSC)

BackgroundIn mammalians, hematopoietic stem cells (HSC) arise in the dorsal aorta from the hemogenic endothelium, followed by their migration to fetal liver and to bone marrow. In zebrafish, kidney is the site of primary hematopoiesis. In humans, the presence of HSC in the fetal or adult kidney has not been established. MethodsWe analyzed the presence of HSC markers in human fetal kidneys by analysis of single-cell datasets. We then analyzed in kidney organoids derived from iPSC, the presence of hematopoietic markers using transcriptome analyses. Results12 clusters were identified of stromal, endothelial, and nephron cell type-specific markers in the two fetal stage (17 weeks) kidney datasets. Among these, expression of hematopoietic cells in Cluster 9 showed expression of primitive markers. Moreover, whole transcriptome analysis of our iPSC-derived kidney organoids revealed induction of the primitive hematopoietic transcription factor RUNX1 as found in the human fetal kidney cortex. ConclusionsThese finding support the presence of cells expressing HSC transcriptome in human kidney. The mechanisms of the appearance of the cells with the same transcriptional features during iPSC-derived kidney organoid generation requires further investigation.

developmental biology↗

bioRxiv2019

Chronic circadian disruption modulates breast cancer cell stemness and their immune microenvironment to drive metastasis in mice

Breast cancer is the most common type and one of the major causes of cancer death in woman worldwide. Epidemiological studies have established a link between night shift work and increased cancer risk, suggesting that circadian disruption may interfere with carcinogenesis. We aim to shed light on the effect of chronic jetlag on mammary tumour development. Therefore, we used a mouse model of spontaneous mammary tumorigenesis that we exposed to chronic circadian disruption. We observed that circadian disruption significantly increases cancer cell dissemination and metastasis. It also enhances the stemness and tumour-initiating potential of tumour cells and creates an immunosuppressive shift in the tumour microenvironment. We finally showed that all these defects can be corrected by the use of a CXCR2 inhibitor. Altogether, our data provide a conceptual framework to better understand and manage the effects of chronic circadian disruption on breast cancer progression.

cancer biology↗

bioRxiv2018

Hierarchical organization of developing HSPC in the human embryonic liver

Despite advances to engineer transplantable hematopoietic stem and progenitor cells (HSPCs) for research and therapy, an in depth characterization of the developing human hematopoietic system is still lacking. The human embryonic liver is at the crossroad of several hematopoietic sites and harbours a complex hematopoietic hierarchy including the first, actively dividing, HSPCs that will further seed the definitive hematopoietic organs. However few is known about the hierarchical phenotypic and functional hematopoietic organization operating at these stages of development.\n\nHere, by using a combination of four endothelial and hematopoietic surface markers i.e. the endothelial-specific marker VE-cadherin, the pan-leukocyte antigen CD45, the hemato-endothelial marker CD34 and the Angiotensin-Converting Enzyme (ACE, CD143), encompassing all early human HSPCs, we identified a hematopoietic hierarchy and, among it, a population co-expressing the four markers that uniquely harbored a proliferation and differentiation potential both ex vivo and in vivo. Moreover, we traced back this population to the yolk sac and AGM sites of hematopoietic emergence. Taken together, our data will help to identify human HSPC self-renewal and amplification mechanisms for future cell therapies.\n\nSUMMARY STATEMENTWe uncover the phenotypic and functional hematopoietic hierarchy operating in the early human embryo. It will bring insights into the mechanisms driving hematopoietic stem cell self-renewal for future cell therapies.

developmental biology↗