Project description:RAS pathway mutations, which are present in 30% of patients with chronic myelomonocytic leukemia (CMML) at diagnosis, confer a high risk of resistance to and progression after hypomethylating agent (HMA) therapy, the current standard of care for the disease. Using single-cell, multi-omics technologies, we sought to dissect the biological mechanisms underlying the initiation and progression of RAS pathway–mutated CMML. We found that RAS pathway mutations induced the transcriptional reprogramming of hematopoietic stem and progenitor cells (HSPCs), which underwent proliferation and monocytic differentiation in response to cell-intrinsic and -extrinsic inflammatory signaling that also impaired immune cells’ functions. HSPCs expanded at disease progression and relied on the NF-KB pathway effector MCL1 to maintain their survival, which explains why patients with RAS pathway–mutated CMML do not benefit from BCL2 inhibitors such as venetoclax. Our study has implications for developing therapies to improve the survival of patients with RAS pathway–mutated CMML.
Project description:We report the gene expression of human chronic myelomonocytic leukemia by performing whole transcriptome shotgun sequencing of peripheral blood mononuclear cells of patients with chronic myelomonocytic leukemia.
Project description:We report the gene expression of human chronic myelomonocytic leukemia by performing whole transcriptome shotgun sequencing of bone marrow mononuclear cells of patients with chronic myelomonocytic leukemia.
Project description:We report the chromatin characteristics of human chronic myelomonocytic leukemia by performing chromatin immunoprecipitation sequencing of histone modifications (ChIP-seq), immunoprecipitation sequencing of (hydroxy-)methylated residues (DIP-seq), and transposase accessibility sequencing (ATAC-seq) of bone marrow mononuclear cells of patients with chronic myelomonocytic leukemia.
Project description:EZH2 was inactivated by shRNA in the RAS-mutated HL-60 acute myeloid leukemia cell line. RNA-seq genome wide expression profiling was used to screen for genes deregulated by EZH2 inactivation within this setting.
Project description:The respective role of genetic and epigenetic heterogeneity in the functional diversity of cells that compose human malignancies remains poorly understood. This question is addressed in chronic myelomonocytic leukemia (CMML), a myeloid neoplasm in which clinical diversity contrasts with a limited genetic heterogeneity. By reprogramming CMML-patient and healthy donor CD34-positive cells, we generated induced pluripotent cell clones (iPSC). In one of the patients, we captured a part of the genetic heterogeneity of the leukemic clone and analyzed five iPSCs with two distinct genetic backgrounds, i.e. with and without KRASG12D mutation. Hematopoietic differentiation of these clones recapitulated the main features of the patient disease, including overproduction of granulomonocytes and dysmegakaryopoiesis. These analyses also disclosed significant discrepancies in the behavior as well as the DNA methylation pattern of hematopoietic cells derived from iPSCs with similar genetic background. Introduction of SRSF2P95H mutation in a KRAS-mutated iPSC partially suppressed the functional and epigenetic gap with the other KRAS-mutated clone. Despite the similar functional behavior of these two clones, only the SRSF2P95H clone responded to low doses of the hypomethylating agent decitabine by restoration of a more balanced production of hematopoietic cells. These analyses unravel additional levels of intraclonal heterogeneity beyond the coding mutations, which may also modulate individual cell response to treatment.
Project description:The c-H-ras proto-oncogene undergoes alternative splicing of the exon termed IDX giving rise to a novel protein of the Ras family, p19 (H-RasIDX). The experiment tests the effect on the transcriptome of overexpressing the wild type and W164A mutated forms of p19. Keywords: genetic modification Three-condition experiment, where wild type p19 H-ras transfection or transfection with a mutated form (p19W164A) were compared to transfection with the negative control (empty pRK5 expression vector) which was used as the common reference. Biological replicates: 3 of each set of treatments, independently grown and harvested. Two technical replicates with dye swapping per comparison.
Project description:In this study, institutional IRB approval was obtained and peripheral blood and bone marrow samples on patients with chronic myelomonocytic leukemia were collected. On the samples, we performed chromatin immuno-precipitation and next generation sequencing to assess histone modifications and epigenetic changes associated with proliferative and dysplastic phenotypes.