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:Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. While BTK inhibition does not impact humoral memory survival, antigen-driven clonal expansion of memory B cells and antibody secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of BTK inhibition. We used Affymetrix genechips to profile the transcriptional changes downstream of BTK inhibition after in vivo B-cell activation by anti-IgD Mice were injected with the novel BTK inhibitor PF-303 2 hours prior to anti-IgD mediated in vivo B-cell activation; B-cells where harvested 2 hours after anti-IgD activation and RNA isolated.
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.
Project description:Mast cells are indispensable for LPS-induced septic hypothermia, in which TNF-α plays an essential role to initiate sepsis. Tec family non-receptor tyrosine kinases ITK and BTK regulate mast cell-derived TNF-α in response to allergic antigen, but their role in LPS-induced TNF-α production by mast cells and related pathology is unclear. We sought to investigate the role(s) of ITK and BTK in mast cell response in septic condition. We found that the absence of ITK and BTK leads to enhanced TNF-α production by bone marrow-derived mast cells (BMMC). Itk-/-Btk-/- mast cells exhibit hyperactive preformed and LPS-induced TNF-α production, along with enhanced expression of other related genes such as NF-κB targeted genes, compared to WT cells. Bone marrow cells from 8-week old WT, Itk-/-, Btk-/- and Itk-/-Btk-/- (double knockout: DKO) C57Bl/6 mice were cultured in murine Interleukin-3/Stem cell factor (IL-3/SCF) supplemented medium for 5 weeks to derive mast cells. WT, Itk-/-, Btk-/- and DKO bone marrow-derived mast cells (BMMC) were factor starved in medium without IL-3/SCF for 12 hours, followed by treatment with PBS (control) or 100 ng/ml LPS for 1 hour. Triplicates of each group were subjected to mouse whole genome genechip microarray analysis. Replicates were randomized on different chips to avoid systematic error.
Project description:To investagate the clinically observed BTK C481S, C481F, C481Y and C481R mutations in the regulation of B cell receptor signaling, we extablished TMD8 cells expressing BTK C481S, C481F, C481Y and C481R in which endogenous BTK was inactivated by ibrutinib. We then performed gene expression profiling analysis using data obtained from RNA-seq of 20 different cells after DMSO or 10 nM ibrutinib treatment from two indenpendent experiments.
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:We describe a previously unappreciated role for Bruton's tyrosine kinase (BTK) in fungal immune surveillance against aspergillosis, an unforeseen complication of BTK inhibitors (BTKi) used for treating B-cell lymphoid malignancies. We studied BTK-dependent fungal responses in neutrophils from diverse populations, including healthy donors, BTKi-treated patients, and X-linked agammaglobulinemia patients. Upon fungal exposure, BTK was activated in human neutrophils in a TLR2-, Dectin-1-, and FcgR-dependent manner, triggering the oxidative burst. BTK inhibition selectively impeded neutrophil-mediated damage to Aspergillus hyphae, primary granule release, and the fungus-induced oxidative burst by abrogating NADPH oxidase subunit p40phox and GTPase RAC2 activation. Moreover, neutrophil-specific Btk deletion in mice enhanced aspergillosis susceptibility by impairing neutrophil function, not recruitment nor lifespan. Conversely, GM-CSF partially mitigated these deficits by enhancing p47phox activation. Our findings underline the crucial role of BTK signaling in neutrophils for antifungal immunity and provide a rationale for GM-CSF use to offset these deficits in susceptible patients.