ABSTRACT: Longitudinal omics data followed by preclinical treatment studies identify proteasome inhibition as potential salvage strategy for ibrutinib-resistant CLL
Project description:Longitudinal omics data followed by preclinical treatment studies identify proteasome inhibition as potential salvage strategy for ibrutinib-resistant CLL
Project description:Chronic lymphocytic leukemia (CLL) is a malignant lymphoproliferative disorder characterized by the accumulation of small mature B cells in blood and secondary lymphoid tissues. Novel drugs, such as the Bruton tyrosine kinase (BTK) inhibitor ibrutinib, have greatly improved survival expectations of CLL patients, nevertheless acquired drug resistance represents a major challenge and the complete molecular mechanisms of which have not been elucidated yet. In order to fill this knowledge gap, we generated a mouse model of ibrutinib resistance by treating mice upon adoptive transfer of Eµ-TCL1 leukemia (TCL1-CLL) continuously with ibrutinib. After an initial response to the treatment, relapse under therapy occurs with an aggressive outgrowth of the malignant cells, resembling observations in patients. To unravel relapse mechanism, we performed transcriptome and proteome analyses of sorted TCL1-CLL cells both during treatment and after relapse. Comparative analysis of these omics layers suggested alterations in the proteasome activity as a driver of ibrutinib resistance. Accordingly, we showed that preclinical treatment with the irreversible proteasome inhibitor (PI) carfilzomib administered upon ibrutinib resistance prolonged survival of mice, thus acting as salvage therapy. Longitudinal proteomic analysis of CLL patients with ibrutinib resistance identified deregulation in protein post-translational modifications. In addition, CLL cells from ibrutinib-resistant patients effectively responded to several PIs in co-culture assays. Altogether, our results from orthogonal omics approaches identified proteasome inhibition as potentially attractive innovative salvage treatment option for CLL patients resistant or refractory to ibrutinib.
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) 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:Chronic lymphocytic leukemia (CLL) cell survival and growth is fueled by aberrant activation of various pro-survival signaling pathways within tumor niches. Specifically, B-cell receptor (BCR) signaling, toll-like receptor signaling, and supportive cellular interactions drive constitutive activation of NF-κB signaling and transcription of proliferative/pro-survival genes. Directly targeting the NF-κB pathway has been a challenge, however, herein, we investigated SpiD3, a spirocyclic dimer and novel NF-κB pathway inhibitor in preclinical models of CLL. Through cross-linking NF-κB proteins, SpiD3 attenuated NF-κB signaling in CLL cells independent of microenvironmental signals. Our integrated multi-omics and functional analyses revealed BCRNF-κB signaling, endoplasmic reticulum stress, oxidative stress, and activation of the unfolded protein response among the top pathways modulated by SpiD3 treatment. This was accompanied by marked inhibition of global protein synthesis, cumulating in profound anti-tumor properties in CLL cells. SpiD3 also modulated tumor microenvironment interactions shown by decreased chemokine and cytokine gene expression as well as decreased CLL chemotaxis towards CXCL-12 and CXCL-13. Moreover, SpiD3 induced apoptosis of stroma-protected primary CLL cells comparable to the BCR-targeting agent, ibrutinib. SpiD3 strikingly demonstrated selective cytotoxicity towards CLL cells compared to healthy lymphocytes, synergized with ibrutinib, and retained its anti-tumor effects in ibrutinib-resistant CLL cells. Altogether, our findings provide preclinical evidence for SpiD3 as an attractive therapeutic agent for CLL, especially in the context of relapsed/refractory disease.
Project description:The Bruton tyrosine kinase (BTK) inhibitor ibrutinib has substantially improved therapeutic options for chronic lymphocytic leukemia (CLL). Although ibrutinib is not curative, it has a profound effect on CLL cells and may create new pharmacologically exploitable vulnerabilities. To identify such vulnerabilities, we developed a systematic approach that combines epigenome profiling (charting the gene-regulatory basis of cell state) with single-cell chemosensitivity profiling (quantifying cell-type-specific drug response) and bioinformatic data integration. By applying our method to a cohort of matched patient samples collected before and during ibrutinib therapy, we identified characteristic ibrutinib-induced changes that provide a starting point for the rational design of ibrutinib combination therapies. Specifically, we observed and validated preferential sensitivity to proteasome, PLK1, and mTOR inhibitors during ibrutinib treatment. More generally, our study establishes a broadly applicable method for investigating treatment-specific vulnerabilities by integrating the complementary perspectives of epigenetic cell states and phenotypic drug responses in primary patient samples.
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: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 leukemia (CLL) is a genetically, epigenetically, and clinically heterogeneous disease. Despite this heterogeneity, the Bruton tyrosine kinase (BTK) inhibitor ibrutinib provides effective treatment for the vast majority of CLL patients. To define the underlining regulatory program, we analyzed high-resolution time courses of ibrutinib treatment in closely monitored patients, combining cellular phenotyping (flow cytometry), single-cell transcriptome profiling (scRNA-seq), and chromatin mapping (ATAC-seq). We identified a consistent regulatory program shared across all patients, which was further validated by an independent CLL cohort. In CLL cells, this program starts with a sharp decrease of NF-κB binding, followed by reduced regulatory activity of lineage-defining transcription factors (including PAX5 and IRF4) and erosion of CLL cell identity, finally leading to the acquisition of a quiescence-like gene signature which was shared across several immune cell types. Nevertheless, we observed patient-to-patient variation in the speed of its execution, which we exploited to predict patient-specific dynamics in the response to ibrutinib based on pre-treatment samples. In aggregate, our study describes the cellular, molecular, and regulatory effects of therapeutic B cell receptor inhibition in CLL at high temporal resolution, and it establishes a broadly applicable method for epigenome/transcriptome-based treatment monitoring. This SuperSeries is composed of the SubSeries listed below.