Project description:Bruton’s tyrosine kinase (BTK) inhibitors such as ibrutinib represent an effective strategy for treatment of chronic lymphocytic leukemia (CLL), although ~30% of patients eventually undergo disease progression. Here we investigated the long-term modulation of the CXCR4dim/CD5bright proliferative fraction (PF) and the CXCR4bright/CD5dim resting fraction (RF) in CLL samples, and their correlation with therapeutic outcome and emergence of ibrutinib resistance. Longitudinal tracking by flow cytometry revealed that PF, initially suppressed by ibrutinib, reappeared upon early disease progression suggesting that PF evaluation could represent a sensitive and specific marker of CLL progression upon ibrutinib treatment. Transcriptomic analyses of PF at progression revealed similar proliferation signatures between pre- and post-treatment PF, demonstrating the emergence upon progression of a newly proliferating cell population.
Project description:Ibrutinib, an irreversible Bruton Tyrosine Kinase (BTK) inhibitor, has revolutionized Chronic Lymphocytic Leukemia (CLL) treatment, but resistances to ibrutinib have emerged in relation or not to BTK mutations. Evolution patterns of CLL before and after ibrutinib therapy are often focused only on leukemic cells but must be investigated in the context of the CLL microenvironment. Single cell RNA-seq and related technologies allow a deeper characterization of cancer and normal cells. We therefore investigated whether ibrutinib treatment drives molecular changes in CLL. Here, we report the monitoring of a CLL patient under ibrutinib treatment using Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-Seq) technology. We report that the short clinical relapse of this patient, driven by BTK mutation, is associated with intra-clonal heterogeneity and transcriptional and phenotypical modifications in both B leukemic and immune cells. These results open new therapeutic strategies for ibrutinib-refractory CLL patients.
Project description:Deletion of the short arm of chromosome 17 (17p-) is one of the most critical genetic variants used in B-CLL risk stratification. The tumor suppressor TP53 maps to this region, and its loss or mutation significantly accelerates B-CLL progression, hampers response to chemotherapy, and shortens survival. While florescent in situ hybridization (FISH) analyses for 17p deletions are routinely performed during clinical diagnoses, mutational analyses of the TP53 gene is not widely available and thus its mutational status is often unknown in patients with CLL. Given the limited clinical data that exists for frontline treatment of patients with CLL harboring TP53 mutations, there is a great need to identify novel treatment strategies for this subset of patients. Herein, we use a CLL mouse model (Eμ-TCL1) in the presence or absence of a common TP53 hot-spot mutation (p53R172H, corresponding to p53R175H in humans) to study its impact on disease progression, survival, response to therapy, and dynamic loss of the remaining wild-type Trp53 allele during the course of B-CLL following BTK inhibitor (ibrutinib). We show that ibrutinib was effective in increasing survival and activated gene and cellular programs outside of the p53 pathway in both settings, and thus, did not place selective pressure on the remaining wild type Trp53 allele. These data demonstrate the potent effect of BTK-inhibition in B-CLL and more importantly, provide evidence that ibrutinib acts as an effective treatment for aggressive forms of B-CLL with TP53 mutation and potentially chemo-resistant refractory disease.
Project description:Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in developed countries. Ibrutinib (PCI-32765), a specific and irreversible inhibitor of Bruton's Tyrosine Kinase (BTK) represents a major step forward in the treatment of CLL. We have undertaken a detailed analysis of the changes happening to the chromatin structure in CLL cells from patients continuously receiving oral doses of ibrutinib. ChIP-seq has been performed for H3K4me3, H3K27ac, H3K27me3 and EZH2 up to 56 days following the beginning of the treatment. We observed that Ibrutinib-dependent lymphocytosis correlates with a global and transient recruitment of EZH2 to active cis-regulatory elements and increased H3K27me3.
Project description:Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in developed countries. Ibrutinib (PCI-32765), a specific and irreversible inhibitor of Bruton's Tyrosine Kinase (BTK) represents a major step forward in the treatment of CLL, but cases of resistance are emerging. We have undertaken a detailed analysis of the changes happening to the chromatin structure in CLL cells from two patients on ibrutinib and showing disease progression. ChIP-seq has been performed for H3K4me3, H3K27ac and H3K27me3. We observed chromatin alterations independent of the disease progression. Raw data is available in EGA under controlled access with accession EGAD00001005220
Project description:Our project is based on the hypothesis that ibrutinib could interfere with chronic lymphocytic leukemia (CLL) microenvironment, modulating the immune response. The aim of the project is to understand if and how ibrutinib modifies the tumor microenvironment accessory cells in CLL, specifically nurse like cells (NLC).
Project description:BTK plays a critical role in B cell malignancies survival. BTK inhibitor was successfully used as first line treatment for CLL in clinical. The emerging unmet needs is new segments are needed for ibrutinib R/R patients. The purpose of this study is to investigate genomic changes and signaling pathway differences after CLL cells were treated with BTK inhibitor (ibrutinib) or degrader (NRX0492).