Project description:Acute myeloid leukemias (AMLs) show variable clinical outcomes. The differentiation state of the normal hematopoietic cell of origin impacts the behavior of AML, with AML from hematopoietic stem cells (HSCs) prone to chemotherapy resistance in model systems. However, the mechanisms by which HSC programs are transmitted to AML are not known. Here, we introduce a leukemogenic translocation into defined human hematopoietic populations, finding that AMLs from HSCs show the highest stem cell content. By epigenetic profiling, we identify a putative program from the normal HSC that collaborates with oncogene-driven programs to confer exceptional aggressiveness. We confirm that components of this program are required for HSC-AML growth and survival and identify RNA polymerase (RNAP) II-mediated transcription as a therapeutic vulnerability. Overall, we propose a mechanism as to how epigenetic programs from the leukemic cell of origin are inherited through transformation to impact heterogeneity in AML biology.
Project description:Local percutaneous thermal ablation is frequently proposed in the management of metastatic diseases. Radiofrequency ablation (RFA) has demonstrated good results when the metastatic disease is limited and slowly evolving. The destruction of solid metastasis by RF leads to inflammatory and immunological mechanisms that remain poorly understood. These pathological events may influence the overall and anti-tumor host immune responses. The purpose of the study is to identify and quantify some immune mechanisms triggered by RFA of pulmonary metastases from colorectal cancer origin.
Project description:Despite significant progress in the mechanistic understanding of epigenetic reprogramming of cells, the basis of 'organ reprogramming' by (epi-)gene-environment interactions remained largely obscured. Here, we use the ether-induced haltere-to-wing transformations in Drosophila as a model for epigenetic “reprogramming� at the whole organism level. Our findings support a mechanistic chain of events explaining why and how brief embryonic exposure to ether leads to organ transformation manifested at the larval stage and on. We show that ether interferes with protein integrity in the egg leading to altered deployment of Hsp90 and widespread repression of Trithorax-mediated establishment of H3K4 tri-methylations throughout the genome. Despite this global suppression of H3K4me3, Ubx targets, and wing development genes preferentially retain higher levels of active chromatin marks. This preferential retention pre-disposes Ubx targets and wing genes for later up-regulation in the larval haltere disc, hence the wing-like outcome. Consistent with compromised protein integrity during the exposure, the penetrance of bithorax transformation increases by genetic or chemical reduction of Hsp90 function. Moreover, joint reduction in Hsp90 and trx gene dosage can cause bithorax transformations even without exposure to ether, supporting underlying epistasis between Hsp90 and trx loss-of-functions. These findings implicate environmental disruption of protein integrity at the onset of histone methylations with a modification of epigenetic memory. The emerging picture provides a unique example in which the alleviation of the Hsp90 ‘capacitor function’ by the environment leads to a morphogenetic shift towards an ancestral-like body plan. The morphogenetic impact of chaperone response during a major setup of epigenetic patterns may be a general scheme for organ reprogramming by environmental cues.
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone. Normal bone marrow CD25+ B-cells, Clonal B-Cells from IgM Monoclonal Gammopathy of Undetermined Significance, and Clonal B-Cells from Waldenström's Macroglobulinemia
Project description:To unveil the still-elusive nature of metazoan replication origins, we identified them genome-wide and at unprecedented high-resolution in mouse ES cells. This allowed initiation sites (IS) and initiation zones (IZ) to be differentiated. We then characterized their genetic signatures and organization and integrated these data with 43 chromatin marks and factors. Our results reveal that replication origins can be grouped into three main classes with distinct organization, chromatin environment and sequence motifs. Class 1 contains relatively isolated, low-efficiency origins that are poor in epigenetic marks and are enriched in an asymmetric AC repeat at the initiation site. Late origins are mainly found in this class. Class 2 origins are particularly rich in enhancer elements. Class 3 origins are the most efficient and are associated with open chromatin and polycomb protein-enriched regions. The presence of Origin G-rich Repeated elements (OGRE) potentially forming G-quadruplexes (G4) was confirmed at most origins. These coincide with nucleosome-depleted regions located upstream of the initiation sites, which are associated with a labile nucleosomes containing H3K64ac. These data demonstrate that specific chromatin landscapes and combinations of specific signatures regulate origin localization. They explain the frequently-observed links between DNA replication and transcription. They also emphasize the plasticity of metazoan replication origins, and suggest that in multicellular eukaryotes, the combination of distinct genetic features and chromatin configurations act in synergy to define and adapt the origin profile.
Project description:SCLC transformation is one of the mechanisms of TKI resistance in lung cancer. To clarify its epigenetic changes, we used RNA-seq to detect the changes of genes in pre-LUAD and post-SCLC transformation cells.
Project description:SCLC transformation is one of the mechanisms of TKI resistance in lung cancer. To clarify its epigenetic changes, we used Chip-seq to detect the changes of H3K9me2 in pre-LUAD and post-SCLC transformation cells.
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone. Copy number analysis using the Affymetrix CytoScan 750K Array to study clonal B-cells from newly-diagnosed patients with IgM MGUS, smoldering, and symptomatic WM. Peripheral T-cells from paired and unpaired controls were also assessed.
Project description:Although information on the molecular pathogenesis of Waldenström’s Macroglobulinemia (WM) has greatly improved in recent years, the exact cellular origin and the mechanisms behind WM transformation from IgM MGUS remain undetermined. Here, we undertook an integrative phenotypic, molecular and genomic approach to study clonal B-cells from newly-diagnosed patients with IgM MGUS (n=22), smoldering (n=17), and symptomatic WM (n=10). Through principal-component-analysis of multidimensional flow cytometry data, we demonstrated overlapping phenotypic profiles between clonal B-cells from IgM MGUS, smoldering and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between FACS-sorted clonal B-cells from the three disease stages. Interestingly, while the transcriptome of the Waldenström’s clone was highly deregulated as compared to CD25-CD22+ normal B-cells, significantly less genes were differentially expressed and specific WM pathways down-regulated while comparing the transcriptome of the Waldenström’s clone vs. its normal phenotypic counterpart: CD25+CD22+dim B-cells. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs. symptomatic WM (18% vs. 20% and 73%, respectively; P =.008), suggesting a multistep transformation of clonal B-cells that albeit benign (i.e.: IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström’s clone.