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: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 the 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: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 of CLL patients, nevertheless acquired drug resistance represents a major challenge the molecular mechanisms of which have not been fully elucidated yet. To overcome this limitation, 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 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 salvage treatment option for CLL patients resistant or refractory to ibrutinib.
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.