Detection of early seeding of Richter transformation in chronic lymphocytic leukemia

Richter transformation (RT) is a paradigmatic evolution of chronic lymphocytic leukemia (CLL) into a very aggressive large B cell lymphoma conferring a dismal prognosis. The mechanisms driving RT remain largely unknown. We characterized the whole genome, epigenome and transcriptome, combined with single-cell DNA/RNA-sequencing analyses and functional experiments, of 19 cases of CLL developing RT. Studying 54 longitudinal samples covering up to 19 years of disease course, we uncovered minute subclones carrying genomic, immunogenetic and transcriptomic features of RT cells already at CLL diagnosis, which were dormant for up to 19 years before transformation. We also identified new driver alterations, discovered a new mutational signature (SBS-RT), recognized an oxidative phosphorylation (OXPHOS)high–B cell receptor (BCR)low-signaling transcriptional axis in RT and showed that OXPHOS inhibition reduces the proliferation of RT cells. These findings demonstrate the early seeding of subclones driving advanced stages of cancer evolution and uncover potential therapeutic targets for RT.The authors thank the Hematopathology Collection registered at the Biobank of Hospital Clínic, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and the Biobank HUB-ICO-IDIBELL (PT20/00171) for sample procurement, S. Martín, F. Arenas, the Genomics Core Facility of the IDIBAPS, CNAG Sequencing Unit, Mission Bio, Omniscope and Barcelona Supercomputing Center for the technical support and the computer resources at MareNostrum4 (RES activity, BCV-2018-3-0001). This study was supported by the la Caixa Foundation (CLLEvolution-LCF/PR/HR17/52150017, Health Research 2017 Program HR17-00221, to E.C.), the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (810287, BCLLatlas, to E.C., J.I.M.-S., H.H. and I.G.), the Instituto de Salud Carlos III and the European Regional Development Fund Una Manera de Hacer Europa (PMP15/00007 to E.C. and RTI2018-094584-B-I00 to D.C.), the American Association for Cancer Research (2021 AACR-Amgen Fellowship in Clinical/Translational Cancer Research, 21-40-11-NADE to F.N.), the European Hematology Association (EHA Junior Research Grant 2021, RG-202012-00245 to F.N.), the Lady Tata Memorial Trust (International Award for Research in Leukaemia 2021-2022, LADY_TATA_21_3223 to F.N.), the Generalitat de Catalunya Suport Grups de Recerca AGAUR (2017-SGR-1142 to E.C., 2017-SGR-736 to J.I.M.-S. and 2017-SGR-1009 to D.C.), the Accelerator award CRUK/AIRC/AECC joint funder partnership (AECC_AA17_SUBERO to J.I.M.-S.), the Fundació La Marató de TV3 (201924-30 to J.I.M.-S.), the Centro de Investigación Biomédica en Red Cáncer (CIBERONC; CB16/12/00225, CB16/12/00334, CB16/12/00236), the Ministerio de Ciencia e Innovación (PID2020-117185RB-I00 to X.S.P.), the Fundación Asociación Española Contra el Cáncer (FUNCAR-PRYGN211258SUÁR to X.S.P.), the Associazione Italiana per la Ricerca sul Cancro Foundation (AIRC 5 × 1,000 no. 21198 to G.G.) and the CERCA Programme/Generalitat de Catalunya. H.P.-A. is a recipient of a predoctoral fellowship from the Spanish Ministry of Science, Innovation and Universities (FPU19/03110). A.D.-N. is supported by the Department of Education of the Basque Government (PRE_2017_1_0100). E.C. is an Academia Researcher of the Institució Catalana de Recerca i Estudis Avançats of the Generalitat de Catalunya. This work was partially developed at the Center Esther Koplowitz (Barcelona, Spain).Peer Reviewed"Article signat per 52 autors/es: Ferran Nadeu, Romina Royo, Ramon Massoni-Badosa, Heribert Playa-Albinyana, Beatriz Garcia-Torre, Martí Duran-Ferrer, Kevin J. Dawson, Marta Kulis, Ander Diaz-Navarro, Neus Villamor, Juan L. Melero, Vicente Chapaprieta, Ana Dueso-Barroso, Julio Delgado, Riccardo Moia, Sara Ruiz-Gil, Domenica Marchese, Ariadna Giró, Núria Verdaguer-Dot, Mónica Romo, Guillem Clot, Maria Rozman, Gerard Frigola, Alfredo Rivas-Delgado, Tycho Baumann, Miguel Alcoceba, Marcos González, Fina Climent, Pau Abrisqueta, Josep Castellví, Francesc Bosch, Marta Aymerich, Anna Enjuanes, Sílvia Ruiz-Gaspà, Armando López-Guillermo, Pedro Jares, Sílvia Beà, Salvador Capella-Gutierrez, Josep Ll. Gelpí, Núria López-Bigas, David Torrents, Peter J. Campbell, Ivo Gut, Davide Rossi, Gianluca Gaidano, Xose S. Puente, Pablo M. Garcia-Roves, Dolors Colomer, Holger Heyn, Francesco Maura, José I. Martín-Subero & Elías Campo "Postprint (published version

Detection of early seeding of Richter transformation in chronic lymphocytic leukemia

B-cell lymphoma; Cancer epigenetics; Chronic lymphocytic leukaemiaLinfoma de células b; Epigenética del cáncer; Leucemia linfocítica crónicaLimfoma de cèl·lules b; Epigenètica del càncer; Leucèmia limfocítica crònicaRichter transformation (RT) is a paradigmatic evolution of chronic lymphocytic leukemia (CLL) into a very aggressive large B cell lymphoma conferring a dismal prognosis. The mechanisms driving RT remain largely unknown. We characterized the whole genome, epigenome and transcriptome, combined with single-cell DNA/RNA-sequencing analyses and functional experiments, of 19 cases of CLL developing RT. Studying 54 longitudinal samples covering up to 19 years of disease course, we uncovered minute subclones carrying genomic, immunogenetic and transcriptomic features of RT cells already at CLL diagnosis, which were dormant for up to 19 years before transformation. We also identified new driver alterations, discovered a new mutational signature (SBS-RT), recognized an oxidative phosphorylation (OXPHOS)high–B cell receptor (BCR)low-signaling transcriptional axis in RT and showed that OXPHOS inhibition reduces the proliferation of RT cells. These findings demonstrate the early seeding of subclones driving advanced stages of cancer evolution and uncover potential therapeutic targets for RT.The authors thank the Hematopathology Collection registered at the Biobank of Hospital Clínic, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and the Biobank HUB-ICO-IDIBELL (PT20/00171) for sample procurement, S. Martín, F. Arenas, the Genomics Core Facility of the IDIBAPS, CNAG Sequencing Unit, Mission Bio, Omniscope and Barcelona Supercomputing Center for the technical support and the computer resources at MareNostrum4 (RES activity, BCV-2018-3-0001). This study was supported by the la Caixa Foundation (CLLEvolution-LCF/PR/HR17/52150017, Health Research 2017 Program HR17-00221, to E.C.), the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (810287, BCLLatlas, to E.C., J.I.M.-S., H.H. and I.G.), the Instituto de Salud Carlos III and the European Regional Development Fund Una Manera de Hacer Europa (PMP15/00007 to E.C. and RTI2018-094584-B-I00 to D.C.), the American Association for Cancer Research (2021 AACR-Amgen Fellowship in Clinical/Translational Cancer Research, 21-40-11-NADE to F.N.), the European Hematology Association (EHA Junior Research Grant 2021, RG-202012-00245 to F.N.), the Lady Tata Memorial Trust (International Award for Research in Leukaemia 2021-2022, LADY_TATA_21_3223 to F.N.), the Generalitat de Catalunya Suport Grups de Recerca AGAUR (2017-SGR-1142 to E.C., 2017-SGR-736 to J.I.M.-S. and 2017-SGR-1009 to D.C.), the Accelerator award CRUK/AIRC/AECC joint funder partnership (AECC_AA17_SUBERO to J.I.M.-S.), the Fundació La Marató de TV3 (201924-30 to J.I.M.-S.), the Centro de Investigación Biomédica en Red Cáncer (CIBERONC; CB16/12/00225, CB16/12/00334, CB16/12/00236), the Ministerio de Ciencia e Innovación (PID2020-117185RB-I00 to X.S.P.), the Fundación Asociación Española Contra el Cáncer (FUNCAR-PRYGN211258SUÁR to X.S.P.), the Associazione Italiana per la Ricerca sul Cancro Foundation (AIRC 5 × 1,000 no. 21198 to G.G.) and the CERCA Programme/Generalitat de Catalunya. H.P.-A. is a recipient of a predoctoral fellowship from the Spanish Ministry of Science, Innovation and Universities (FPU19/03110). A.D.-N. is supported by the Department of Education of the Basque Government (PRE_2017_1_0100). E.C. is an Academia Researcher of the Institució Catalana de Recerca i Estudis Avançats of the Generalitat de Catalunya. This work was partially developed at the Center Esther Koplowitz (Barcelona, Spain)

BCL3-rearrangements in B-cell lymphoid neoplasms occur in two breakpoint clusters associated with different diseases

The t(14;19)(q32;q13) often juxtaposes BCL3 with IGH resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3-rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in CLL but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter 4 tumors transformed to a large B-cell lymphoma. We designed a novel FISH assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively

BCL3-rearrangements in B-cell lymphoid neoplasms occur in two breakpoint clusters associated with different diseases

The t(14;19)(q32;q13) often juxtaposes BCL3 with immunoglobulin heavy chain (IGH) resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3 rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in chronic lymphocytic leukemia (CLL) but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter four tumors transformed to a large B-cell lymphoma. We designed a novel fluorescence in situ hybridization assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively

Challenges with approved targeted therapies against recurrent mutations in CLL: a place for new actionable targets

Chronic lymphocytic leukemia (CLL) is characterized by a high degree of genetic variability and interpatient heterogeneity. In the last decade, novel alterations have been described. Some of them impact on the prognosis and evolution of patients. The approval of BTK inhibitors, PI3K inhibitors and Bcl-2 inhibitors has drastically changed the treatment of patients with CLL. The effect of these new targeted therapies has been widely analyzed in TP53-mutated cases, but few data exist about the response of patients carrying other recurrent mutations. In this review, we describe the biological pathways recurrently altered in CLL that might have an impact on the response to these new therapies together with the possibility to use new actionable targets to optimize treatment responses.The group has been supported by the Spanish Ministry of Science and Innovation through the Plan Estatal de Investigación Científica y Técnica y de Innovación [RTI2018-094584-B-I00] and was cofounded by the European Regional Development Fund (ERDF) and the CERCA program from Generalitat de Catalunya, Centro de Investigación Biomédica en Cáncer (CIBERONC) and Generalitat de Catalunya [2017 SGR 1009]

SF3B1 mutation-mediated sensitization to H3B-8800 splicing inhibitor in chronic lymphocytic leukemia

Splicing factor 3B subunit 1 (SF3B1) is involved in pre-mRNA branch site recognition and is the target of antitumor-splicing inhibitors. Mutations in SF3B1 are observed in 15% of patients with chronic lymphocytic leukemia (CLL) and are associated with poor prognosis, but their pathogenic mechanisms remain poorly understood. Using deep RNA-sequencing data from 298 CLL tumor samples and isogenic SF3B1 WT and K700E-mutated CLL cell lines, we characterize targets and pre-mRNA sequence features associated with the selection of cryptic 3' splice sites upon SF3B1 mutation, including an event in the MAP3K7 gene relevant for activation of NF-κB signaling. Using the H3B-8800 splicing modulator, we show, for the first time in CLL, cytotoxic effects in vitro in primary CLL samples and in SF3B1-mutated isogenic CLL cell lines, accompanied by major splicing changes and delayed leukemic infiltration in a CLL xenotransplant mouse model. H3B-8800 displayed preferential lethality towards SF3B1-mutated cells and synergism with the BCL2 inhibitor venetoclax, supporting the potential use of SF3B1 inhibitors as a novel therapeutic strategy in CLL.The work of the authors is supported by the Spanish Ministry of Science and Innovation through the Plan Estatal de Investigación Científica y Técnica y de Innovación (RTI2018-094584-B-I00; PID2021-123165OB-I00; BFU-2017-89308-P, PID2020-114630GB-I00) and was cofounded by the European Regional Development Fund (ERDF), European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program ERC-AdG-LS2-670146 l, CERCA program from Generalitat de Catalunya, Centre of Excellence Severo Ochoa Award (CEX2020-001049) to the Centre for Genomic Regulation of the Barcelona Institute of Science and Technology, Centro de Investigación Biomédica en Cáncer (CIBERONC) (CB16/12/334), Agència de Gestió d’Ajuts Universitaris i de Recerca, Generalitat de Catalunya (2017 SGR 1009; 2021 SGR-1294) and Asociación Española Contra el Cancer (AECC) (PRYGN223298VALC). We thank Elias Campo for sharing transcriptomics data from ICGC consortium and for reviewing the manuscript. We thank Suzanne Mays, Estefania Mancini, Malgorzata Rogalska, and Ferran Nadeu for their help and all the laboratory members from Juan Valcarcel’s group

Systems biology drug screening identifies statins as enhancers of current therapies in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a B lymphoid malignancy highly dependent on the microenvironment. Despite new targeted therapies such as ibrutinib and venetoclax, disease progression and relapse remain an issue. CLL cell interactions with the supportive tissue microenvironment play a critical role in disease pathogenesis. We used a platform for drug discovery based on systems biology and artificial intelligence, to identify drugs targeting key proteins described to have a role in the microenvironment. The selected compounds were screened in CLL cell lines in the presence of stromal cells to mimic the microenvironment and validated the best candidates in primary CLL cells. Our results showed that the commercial drug simvastatin was the most effective and selective out of the tested compounds. Simvastatin decreased CLL cell survival and proliferation as well as cell adhesion. Importantly, this drug enhanced the antitumor effect of venetoclax and ibrutinib. We proposed that systems biology approaches combined with pharmacological screening could help to find new drugs for CLL treatment and to predict new combinations with current therapies. Our results highlight the possibility of repurposing widely used drugs such as statins to target the microenvironment and to improve the efficacy of ibrutinib or venetoclax in CLL cells.The study was supported by research funding from the Spanish Ministry of Economy and Competitiveness through the Plan Estatal de Investigación Científica y Técnica y de Innovación (MINECO) RTI2018-094584-B-I00 [to DC] and was cofunded by the European Regional Development Fund [ERDF] and the CERCA program from Generalitat de Catalunya, Centro de Investigación Biomédica en Cáncer [CIBERONC] [CB16/12/00334 and CB16/12/00225] and Generalitat de Catalunya Suport Grups de Recerca [2017 SGR 1009]. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 306240. NG is a recipient of a predoctoral fellowship from AGAUR, L.R. is a recipient of a postdoctoral fellowship from AGAUR (PERIS), ILO is a recipient of the PhD4MD program and HPA is a recipient of a predoctiral fellowship from Spanish Ministry of Economy and Competitiveness (FPU

BCL3 rearrangements in B-cell lymphoid neoplasms occur in two breakpoint clusters associated with different diseases

The t(14;19)(q32;q13) often juxtaposes BCL3 with immunoglobulin heavy chain (IGH) resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3 rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in chronic lymphocytic leukemia (CLL) but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter four tumors transformed to a large B-cell lymphoma. We designed a novel fluorescence in situ hybridization assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively

Detection of early seeding of Richter transformation in chronic lymphocytic leukemia

Richter transformation (RT) is a paradigmatic evolution of chronic lymphocytic leukemia (CLL) into a very aggressive large B cell lymphoma conferring a dismal prognosis. The mechanisms driving RT remain largely unknown. We characterized the whole genome, epigenome and transcriptome, combined with single-cell DNA/RNA-sequencing analyses and functional experiments, of 19 cases of CLL developing RT. Studying 54 longitudinal samples covering up to 19 years of disease course, we uncovered minute subclones carrying genomic, immunogenetic and transcriptomic features of RT cells already at CLL diagnosis, which were dormant for up to 19 years before transformation. We also identified new driver alterations, discovered a new mutational signature (SBS-RT), recognized an oxidative phosphorylation (OXPHOS)(high)-B cell receptor (BCR)(low)-signaling transcriptional axis in RT and showed that OXPHOS inhibition reduces the proliferation of RT cells. These findings demonstrate the early seeding of subclones driving advanced stages of cancer evolution and uncover potential therapeutic targets for RT.Single-cell genomic and transcriptomic analyses of longitudinal samples of patients with Richter syndrome reveal the presence and dynamics of clones driving transformation from chronic lymphocytic leukemia years before clinical manifestatio