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).
Project description:Inactivating mutations in the NF-kB inhibitor NFKBIE are frequent in chronic lymphocytic leukemia (CLL) and have been associated with accelerated disease progression and inferior responses to chemotherapy. To further understand the role of NFKBIE mutations in CLL, we disrupted by CRISPR/Cas9 editing the NFKBIE gene in CLL cells derived from the Eμ-TCL1 transgenic mouse model and investigated how this will affect CLL growth and response to B cell receptor inhibitor treatment. In vitro and adoptive transfer experiments showed that NFKBIE-mutated cells have a growth advantage over NFKBIE-wild type cells when exposed to microenvironmental signals that activate the canonical NF-kB pathway and can induce alterations within the tumor microenvironment that may allow for escape from immune surveillance, including the expansion of CD8+ T cells with an exhausted phenotype and increased expression of PD-L1 on the malignant B cells. Consistent with these findings, significantly greater expression of the exhaustion markers PD1 and TIGIT was observed on T cells from CLL patients with NFKBIE-mutated compared to NFKBIE-wild type leukemia. In addition, in vitro and in vivo experiments showed that NFKBIE-mutated murine CLL cells are selectively resistant to BTK inhibitor treatment while remaining sensitive to treatment with a PI3K or SYK inhibitor. Reduced sensitivity to BTK inhibitor treatment was also observed in a series of 229 ibrutinib-treated CLL patients showing inferior outcomes for the NFKBIE-mutated cases. These findings provide evidence that NFKBIE-mutated CLL cells reshape and are selected by the tumor microenvironment and may account for suboptimal ibrutinib responses.
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: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:Here we identify that drug-resistant BTK mutations occur in distinct enzymatic classes, some of which render BTK enzymatically impaired while conferring novel protein-protein interactions to sustain B-cell receptor (BCR) signaling.
Project description:We collected three timepoint blood samples from a CLL patient underwent BTK inhibitor treatment. We performed single cell RNA sequencing on these samples to track expression heterogeneity of malignant B-cell populations over time.
Project description:Continuous treatment with ibrutinib not only exerts tumor control but also enhances T cell function in patients with chronic lymphocytic leukemia (CLL). We conducted longitudinal multiomics analyses in samples from CLL patients receiving ibrutinib upfront to identify potential adaptive mechanisms to Bruton Tyrosine Kinase (BTK) inhibition during the first 12 months of continuous therapy. Wefound that in T cells, ibrutinib reduced the expression of exhaustion markers, the proportion of Tregs and Tfh cells, as well as expression of genes related to activation, proliferation, differentiation, and metabolism. In CLL cells, we observed a downregulation of immunosuppression, adhesion, and migration mechanisms. Adaptation at molecular level, characterized by an increase in cancer cell fraction of CLL cells with mutated driver genes, was observed in around half of the patients. Interestingly, BTK C481S mutations were detected as early as after 6 months of treatment, particularly enriched in subsets of malignant cells retaining migrative capacity. These CLL cells with potential migrative capacity under ibrutinib also exhibited a distinct transcriptomic profile including upregulation of mTOR-AKT and Myc pathways. We identified high expression of TMBIM6 as a potential novel independent poor prognostic factor. Of note, BIA, a TMBIM6 antagonist, induced CLL cell apoptosis and synergized with ibrutinib. In summary, our comprehensive multi-omics analysis of CLL patients undergoing ibrutinib therapy has unveiled early immunomodulatory effects on T cells and adaptative mechanisms in CLL cells. These findings can contribute to the identification of resistance mechanisms and the discovery of novel therapeutic targets.
Project description:Bruton's tyrosine kinase (Btk) is important for B lymphocyte development. To identify genes that are differentially expressed in primary B cells lacking functional Btk, splenocytes from X-linked immunodeficiency (Xid), Btk knockout (KO) and immunocompetent CBA mice, were used in microarrays containing more than 12,000 genes and expressed sequence tags (ESTs). We found 4515 transcripts expressed in duplicate experiments in all three strains. Out of these, 38 were differentially expressed genes (21 up-regulated >2 fold and 17 down-regulated <-2 fold) between CBA and Btk defective mice. Ten out of these genes were selected and quantitative Real-Time PCR was conducted for validation and further investigation. Real-Time experiments correlated nicely with the microarray data. No definitive phenotypic difference has previously been reported between Xid and Btk KO mice. We found 7 genes, whose expression differed (>2 fold) between the two strains. Moreover, when the 38 genes, which differed between immunocompetent CBA and Btk defective mice were ranked according to fold-increase, the levels in Btk KO mice were significantly more altered. This suggests that the defect in Btk KO mice is more severe and demonstrates that the mutant Btk protein in Xid mice does not generally function as dominant negative form. Experiment Overall Design: 6 Affymetrix U74Av2 GeneChip arrays was run. Three initially with CBA, Xid and Btk KO mice and then additional three chips with new RNA preperations from new CBA, Xid and Btk KO mice.