BUSCADOR RECOLECTA

Coenzyme Q10 (CoQ10 ) plays a crucial role in mitochondria as an electron carrier within the mitochondrial respiratory chain (MRC) and is an essential antioxidant. Mutations in genes responsible for CoQ10 biosynthesis (COQ genes) cause primary CoQ10 deficiency, a rare and heterogeneous mitochondrial disorder with no clear genotype-phenotype association, mainly affecting tissues with high-energy demand including brain and skeletal muscle (SkM). Here, we report a four-year-old girl diagnosed with minor mental retardation and lethal rhabdomyolysis harboring a heterozygous mutation (c.483G > C (E161D)) in COQ4. The patient's fibroblasts showed a decrease in [CoQ10 ], CoQ10 biosynthesis, MRC activity affecting complexes I/II + III, and respiration defects. Bona fide induced pluripotent stem cell (iPSCs) lines carrying the COQ4 mutation (CQ4-iPSCs) were generated, characterized and genetically edited using the CRISPR-Cas9 system (CQ4ed -iPSCs). Extensive differentiation and metabolic assays of control-iPSCs, CQ4-iPSCs and CQ4ed -iPSCs demonstrated a genotype association, reproducing the disease phenotype. The COQ4 mutation in iPSC was associated with CoQ10 deficiency, metabolic dysfunction, and respiration defects. iPSC differentiation into SkM was compromised, and the resulting SkM also displayed respiration defects. Remarkably, iPSC differentiation in dopaminergic or motor neurons was unaffected. This study offers an unprecedented iPSC model recapitulating CoQ10 deficiency-associated functional and metabolic phenotypes caused by COQ4 mutation. Stem Cells 2017;35:1687-1703., This work was supported by the ISCIII/FEDER (E-Rare-2 Call PI12/03112 to P.M.), FIS/ISCIII/FEDER project (PI14/01962 to P.N.) and the European Research Council (ERC-2014-CoG-646903 to P.M.). D.R.M. and C.P. are supported by PFIS scholarships (FI11/0511 and FI12/00468, respectively). C.B is supported by a Miguel Servet II contract (CPII13/00011). P.M. also acknowledges the financial support from The Obra Social La Caixa-Fundacio Josep Carreras and The Generalitat de Catalunya (SGR330). P.M. and J.L.-B. are investigators of the Spanish Cell Therapy cooperative network (TERCEL). A.G. is supported by Ramon y Cajal Program (RyC-2013-13221)., Sí

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death., Plan Nacional de I+D+I co-funding FEDER [PI15/00892 and PI18/01527 to M.F.F. and A.F.F.; PI16/01318 and PI14/01244 to C.L.]; ISCIII-Subdireccion General de Evaluacion y Fomento de la Investigacion, and Plan Nacional de I+D+I 2008–2011/FEDER [CP11/00131 to A.F.F.]; IUOPA (to G.F.B. and M.I.S.); Fundacion
Cientifica de la AECC (to R.G.U.); Ministry of Economy and Competitiveness Juan de la Cierva postdoctoral fellowships [FJCI-2015-26965 to J.R.T., IJCI-2015-
23316 to V.L.]; Fundacion Ramon Areces (to M.F.F); FICYT (to E.G.T., M.G.G., A.C.); Asturias Regional Government [GRUPIN14-052 to M.F.F.]; Gobierno del
Principado de Asturias, PCTI-Plan de Ciencia, Tecnologia e Innovacion co-funding Fondos FEDER (grant number IDI/2018/146 to M.F.F. and IDI/2018/144 to
C.L.); Deutsche Forschungsgemeinschaft (DFG) [SFB960 to A.V.G., R.D.]; European Research Council [CoG-2014-646903]; Spanish Ministry of Economy and Competitiveness [SAF-SAF2013-43065 to P.M.]; Asociacion Española Contra el Cancer [AECC-CI-2015]; FERO Foundation, and the ISCIII [PI14-01191 to C.B.]; P.M. acknowledges financial support from The Obra Social La Caixa Fundacio Josep Carreras and The Generalitat de Catalunya (SGR330). P.M. an investigator from the Spanish Cell Therapy cooperative network (TERCEL). The IUOPA is supported by the Obra Social Liberbank-Cajastur, Spain. Funding for open access charge: Plan Nacional de I+D+I co-funding FEDER [PI18/01527].

Background There are few therapeutic options available for patients with B-cell acute lymphoblastic leukemia (B-ALL) relapsing as CD19 - either after chemotherapy or CD19-targeted immunotherapies. CD22-chimeric antigen receptor (CAR) T cells represent an attractive addition to CD19-CAR T cell therapy because they will target both CD22 + CD19 - B-ALL relapses and CD19 - preleukemic cells. However, the immune escape mechanisms from CD22-CAR T cells, and the potential contribution of the epitope binding of the anti-CD22 single-chain variable fragment (scFv) remain understudied. Methods Here, we have developed and comprehensively characterized a novel CD22-CAR (clone hCD22.7) targeting a membrane-distal CD22 epitope and tested its cytotoxic effects against B-ALL cells both in in vitro and in vivo assays. Results Conformational epitope mapping, cross-blocking, and molecular docking assays revealed that the hCD22.7 scFv is a high-affinity binding antibody which specifically binds to the ESTKDGKVP sequence, located in the Ig-like V-type domain, the most distal domain of CD22. We observed efficient killing of B-ALL cells in vitro, although the kinetics were dependent on the level of CD22 expression. Importantly, we show an efficient in vivo control of patients with B-ALL derived xenografts with diverse aggressiveness, coupled to long-term hCD22.7-CAR T cell persistence. Remaining leukemic cells at sacrifice maintained full expression of CD22, ruling out CAR pressure-mediated antigen loss. Finally, the immunogenicity capacity of this hCD22.7-scFv was very similar to that of other CD22 scFv previously used in adoptive T cell therapy. Conclusions We report a novel, high-affinity hCD22.7 scFv which targets a membrane-distal epitope of CD22. 4-1BB-based hCD22.7-CAR T cells efficiently eliminate clinically relevant B- CD22 high and CD22 low ALL primary samples in vitro and in vivo. Our study supports the clinical translation of this hCD22.7-CAR as either single or tandem CD22-CD19-CAR for both naive and anti-CD19-resistant patients with B-ALL., This work was supported by the European Research Council (CoG-2014-
646903, PoC-2018-811220), the Spanish Ministry of Economy and Competitiveness
(MINECO-SAF2016-80481-R), the Fundación Uno entre Cienmil, the Obra Social La
Caixa (LCF/PR/HR19/52160011), the Spanish Cancer Association and Leo Messi
Foundation to PM. CB was supported by the ISCIII/FEDER (PI17/01028). TVH and
SRZ were supported by Marie Sklodowska Curie Fellowships (792923 and 795833,
respectively). DSM was supported by a Sara Borrell fellowship from the ISCIII. MLB
was supported by a FPI scholarship from the MINECO. PM is an investigator of the
Spanish Cell Therapy Network (TERCEL).

Supplementary figures and supplementary data tables from MethylationEPIC arrays (Tejedor et al), plus a compiled dataset including raw methylation intensities, processed β-values and Phenotypic data from HumanMethylation450 arrays collected from datasets GSE63409, GSE49618, GSE88824 and GSE49031, and HumanMethylationEPIC arrays deposited in E-MTAB-6315 entry from ArrayExpress., Epigenetic regulation plays an important role in cellular development and differentiation. A detailed map of the DNA methylation dynamics that occur during cell differentiation would contribute to decipher the molecular networks governing cell fate commitment. In this study we used the most recent Illumina MethylationEPIC Beadchip platform to describe the genome-wide DNA methylation changes observed throughout hematopoietic maturation by analyzing multiple hematopoietic cell types at different developmental stages., Grants: European Commission: INFANTLEUKEMIA - GENOMIC, CELLULAR AND DEVELOPMENTAL RECONSTRUCTION OFINFANT MLL-AF4+ ACUTE LYMPHOBLASTIC LEUKEMIA (646903)., Peer reviewed

Supplementary data files corresponding to manuscript: Urdinguio, Lopez et al., Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death., European Commission: INFANTLEUKEMIA - GENOMIC, CELLULAR AND DEVELOPMENTAL RECONSTRUCTION OFINFANT MLL-AF4+ ACUTE LYMPHOBLASTIC LEUKEMIA (646903), Peer reviewed

B cell acute lymphoblastic leukemia (B-ALL) is the most common childhood cancer. As predicted by its prenatal origin, infant B-ALL (iB-ALL) shows an exceptionally silent DNA mutational landscape, suggesting that alternative epigenetic mechanisms may substantially contribute to its leukemogenesis. Here, we have integrated genome-wide DNA methylome and transcriptome data from 69 patients with de novo MLL-rearranged leukemia (MLLr) and non-MLLr iB-ALL leukemia uniformly treated according to the Interfant-99/06 protocol. iB-ALL methylome signatures display a plethora of common and specific alterations associated with chromatin states related to enhancer and transcriptional control in normal hematopoietic cells. DNA methylation, gene expression, and gene coexpression network analyses segregated MLLr away from non-MLLr iB-ALL and identified a coordinated and enriched expression of the AP-1 complex members FOS and JUN and RUNX factors in MLLr iB-ALL, consistent with the significant enrichment of hypomethylated CpGs in these genes. Integrative methylome-transcriptome analysis identified consistent cancer cell vulnerabilities, revealed a robust iB-ALL–specific gene expression–correlating dmCpG signature, and confirmed an epigenetic control of AP-1 and RUNX members in reshaping the molecular network of MLLr iB-ALL. Finally, pharmacological inhibition or functional ablation of AP-1 dramatically impaired MLLr-leukemic growth in vitro and in vivo using MLLr-iB-ALL patient–derived xenografts, providing rationale for new therapeutic avenues in MLLr-iB-ALL., We thank CERCA/Generalitat de Catalunya (SGR180) and Fundació Josep Carreras-Obra Social la Caixa for their institutional support. Financial support for this work was obtained from the European Research Council (CoG-2014-646903 and PoC-2018-811220 to PM), the Spanish Ministry of Economy and Competitiveness (SAF-2019-108160-R and SAF2016-76758-R to PM and IV, respectively), the Spanish Association against cancer (AECC-CI-2015 and PROYE18061FERN to CB and MFF), the Fundación Uno entre Cienmil (to PM), the Health Institute Carlos III (ISCIII/FEDER, PI17/01028, PI15/00892, PI18/01527 to CB and AFF/MFF, respectively). We also acknowledge the Plan de Ciencia, Tecnología e Innovación from the Asturias Government cofunding 2018–2022/FEDER (IDI/2018/146to MFF). MFF also acknowledges funding from Fundación General CSIC (0348_CIE_6_E). PM also acknowledges financial support from Fundación Leo Messi. JRT and MV are supported by Juan de la Cierva fellowships by the Spanish Ministry of Science and Innovation (FJCI-2015-26965, IJC2018-36825-I, IJCI-2017-3317) and IUOPA-ISPA-FINBA (The IUOPA is supported by the Obra Social Cajastur-Liberbank, Spain). RTR is supported by a fellowship from the AECC scientific foundation. RFP and PSO are supported by the Severo Ochoa program (BP17-114 and BP17-165, respectively)., Peer reviewed

This paper was funded by grants to MP by the Spanish Ministry of Science, Innovation and Universities (SAF2017-87990-R and EUR2019-103835) and elaborated at the Josep Carreras Leukaemia Research Institute (IJC, Badalona, Barcelona) and IDIBELL Research Institute (L’Hospitalet de Llobregat, Barcelona). OdB is funded by a Juan de la Cierva—Formación fellowship from the Spanish Ministry of Science, Innovation and Universities (FJCI-2017-32430). AM is funded by the Spanish Ministry of Science, Innovation and Universities, which is part of the Agencia Estatal de Investigación (AEI), through grant PRE2018-083183 (cofunded by the European Social Fund). Work in PM and CB’s lab was supported by the European Research Council (CoG-2014646903), the Spanish Ministry of Economy and Competitiveness (SAF-2016-80481-R), Uno entre Cien Mil Foundation, the Leo Messi Foundation, the Asociación Española Contra el Cáncer (AECC-CI-2015), and the ISCIII/FEDER (PI17/01028). ¡

Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor (CAR) T cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CART fratricide. CD1a is exclusively expressed in cortical T-ALL (coT-ALL), a major subset of T-ALL, and retained at relapse. This article reports that the expression of CD1a is mainly restricted to developing cortical thymocytes, and neither CD34+ progenitors nor T cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. We thus developed and preclinically validated a CD1a-specific CAR with robust and specific cytotoxicity in vitro and antileukemic activity in vivo in xenograft models of coT-ALL, using both cell lines and coT-ALL patient–derived primary blasts. CD1a-CARTs are fratricide resistant, persist long term in vivo (retaining antileukemic activity in re-challenge experiments), and respond to viral antigens. Our data support the therapeutic and safe use of fratricide-resistant CD1a-CARTs for relapsed/refractory coT-ALL., This research was supported by the European Research Council (H2020)
(CoG-2014-646903), the Agencia Estatal de Investigacion/European Re- ´
gional Development Fund (SAF2016-80481-R and SAF2016-75442-R),
and the Catalunya Government (SGR330 and PERIS 2017) (P.M.), as well
as the Asociacion Española Contra el C ´ ancer, Beca FERO, and the ´
ISCIII/FEDER (PI17/01028) (C.B.). P.M. also acknowledges institutional
support from the Obra Social La Caixa-Fundacio Josep Carreras. J.G.P. `
holds a Miguel Servet contract (CP15/00014), and O.B.-L. is supported
by an AGAUR-FI fellowship from the Catalan Government. P.M. is an
investigator of the Spanish Cell Therapy cooperative network (TERCEL)., Peer reviewed

Aberrant DNA hypermethylation is a hallmark of cancer although the underlying molecular mechanisms are still poorly understood. To study the possible role of 5-hydroxymethylcytosine (5hmC) in this process we analyzed the global and locus-specific genome-wide levels of 5hmC and 5-methylcytosine (5mC) in human primary samples from 12 non-tumoral brains and 53 gliomas. We found that the levels of 5hmC identified in non-tumoral samples were significantly reduced in gliomas. Strikingly, hypo-hydroxymethylation at 4627 (9.3%) CpG sites was associated with aberrant DNA hypermethylation and was strongly enriched in CpG island shores. The DNA regions containing these CpG sites were enriched in H3K4me2 and presented a different genuine chromatin signature to that characteristic of the genes classically aberrantly hypermethylated in cancer. As this 5mC gain is inversely correlated with loss of 5hmC and has not been identified with classical sodium bisulfite-based technologies, we conclude that our data identifies a novel 5hmC-dependent type of aberrant DNA hypermethylation in glioma., This work has been financially supported by: the Plan Nacional de I+D+I 2013–2016/FEDER (PI15/00892 to M.F.F. and A.F.F.; RTC-2015-3393-1 to A.F.F.); the ISCIII-Subdirección General de Evaluación y Fomento de la Investigación, and the Plan Nacional de I+D+I 2008–2011/FEDER (CP11/00131 to A.F.F.); IUOPA (to G.F.B. and M.S); the Fundación Científica de la AECC (to R.G.U.); the Fundación Ramón Areces (to M.F.F); FICYT (to E.G.T., M.G.G. and A.C.); and the Asturias Regional Government (GRUPIN14-052 to M.F.F.). Work in P.M. laboratory is supported by the European Research Council (CoG-2014-646903), the Spanish Ministry of Economy-Competitiveness (SAF-SAF2013-43065), the Obra Social La Caixa-Fundaciò Josep Carreras, and the Generalitat de Catalunya. P.M. is an investigator in the Spanish Cell Therapy cooperative network (TERCEL). The IUOPA is supported by the Obra Social Cajastur-Liberbank, Spain., Peer reviewed

et al., Coenzyme Q (CoQ) plays a crucial role in mitochondria as an electron carrier within the mitochondrial respiratory chain (MRC) and is an essential antioxidant. Mutations in genes responsible for CoQ biosynthesis (COQ genes) cause primary CoQ deficiency, a rare and heterogeneous mitochondrial disorder with no clear genotype–phenotype association, mainly affecting tissues with high-energy demand including brain and skeletal muscle (SkM). Here, we report a four-year-old girl diagnosed with minor mental retardation and lethal rhabdomyolysis harboring a heterozygous mutation (c.483G > C (E161D)) in COQ4. The patient's fibroblasts showed a decrease in [CoQ], CoQ biosynthesis, MRC activity affecting complexes I/II + III, and respiration defects. Bona fide induced pluripotent stem cell (iPSCs) lines carrying the COQ4 mutation (CQ4-iPSCs) were generated, characterized and genetically edited using the CRISPR-Cas9 system (CQ4-iPSCs). Extensive differentiation and metabolic assays of control-iPSCs, CQ4-iPSCs and CQ4-iPSCs demonstrated a genotype association, reproducing the disease phenotype. The COQ4 mutation in iPSC was associated with CoQ deficiency, metabolic dysfunction, and respiration defects. iPSC differentiation into SkM was compromised, and the resulting SkM also displayed respiration defects. Remarkably, iPSC differentiation in dopaminergic or motor neurons was unaffected. This study offers an unprecedented iPSC model recapitulating CoQ deficiency-associated functional and metabolic phenotypes caused by COQ4 mutation., This work was supported by the ISCIII/FEDER (E-Rare-2 Call PI12/03112 to P.M.), FIS/ISCIII/FEDER project (PI14/01962 to P.N.) and the European Research Council (ERC-2014-CoG646903 to P.M.). D.R.M. and C.P. are supported by PFIS scholarships
(FI11/0511 and FI12/00468, respectively). C.B is supported by a Miguel Servet II contract (CPII13/00011). P.M. also acknowledges the financial support from The Obra Social La Caixa-Fundacio Josep Carreras and The Generalitat de Catalunya (SGR330). P.M. and J.L.-B. are investigators of the Spanish Cell Therapy cooperative network (TERCEL). A.G. is supported by Ramon y Cajal Program (RyC-2013–13221)., Peer Reviewed

et al., Induced pluripotent stem cells (iPSCs) are a powerful tool for disease modeling. They are routinely generated from healthy donors and patients from multiple cell types at different developmental stages. However, reprogramming leukemias is an extremely inefficient process. Few studies generated iPSCs from primary chronic myeloid leukemias, but iPSC generation from acute myeloid or lymphoid leukemias (ALL) has not been achieved. We attempted to generate iPSCs from different subtypes of B-ALL to address the developmental impact of leukemic fusion genes. OKSM(L)-expressing mono/polycistronic-, retroviral/lentiviral/episomal-, and Sendai virus vector-based reprogramming strategies failed to render iPSCs in vitro and in vivo. Addition of transcriptomic-epigenetic reprogramming “boosters” also failed to generate iPSCs from B cell blasts and B-ALL lines, and when iPSCs emerged they lacked leukemic fusion genes, demonstrating non-leukemic myeloid origin. Conversely, MLL-AF4-overexpressing hematopoietic stem cells/B progenitors were successfully reprogrammed, indicating that B cell origin and leukemic fusion gene were not reprogramming barriers. Global transcriptome/DNA methylome profiling suggested a developmental/differentiation refractoriness of MLL-rearranged B-ALL to reprogramming into pluripotency., This work was supported by the European Research Council to P.M. (ERC-2014-CoG-646903), the ISCIII/FEDER (E-Rare-2 Call PI12/03112 to P.M. and PI14/01191 to C.B.), MINECO (SAF2013-43065 to P.M.), and the Spanish Association Against Cancer (AECC) to P.M. and C.B. C.B. is supported by a Miguel Servet II contract (CPII13/00011). D.R.M. and A.M.-L. are supported by PFIS (FI11/0511) and FPI (BES-2014-067844) scholarships, respectively. P.M. also acknowledges financial support from the Obra Social La Caixa, Fundaciò Josep Carreras and The Generalitat de Catalunya (SGR330). Open Access funded by European Research Council., Peer Reviewed

This meeting held at the University of Barcelona in March 2017, brought together scientists and clinicians worldwide to discuss current and future clinico-biological implications of intratumoral heterogeneity (ITH) and subclonal evolution in cancer diagnosis, patient stratification, and treatment resistance in diagnosis, treatment and follow-up. There was consensus that both longitudinal and tumor multi-region studies in matched samples are needed to better understand the dynamics of ITH. The contribution of the epigenome and microenvironment to ITH and subclone evolution remains understudied. It was recommended to combine computational, pathology and imaging tools to study the role of the microenvironment in subclone selection/ evolution., I.V. is funded by Spanish Ministry of Economy and Competitiveness (SAF2016-76758-R), The Fundación Ramón Areces and European Research Council (ERC
StG-2014-637904). P.M. is supported by European Research Council (CoG-2014-646903), Spanish Ministry of Economy and Competitiveness (SAF-2016-80481-R & RTC-2016-4603-1), Generalitat de Catalunya (SGR-330)
and Obra Social La Caixa-Fundación Josep Carreras.
A.S.P. is funded by Ramón & Cajal Program from Spanish Ministry of Economy and Competitiveness (RYC-2015-
17534) and Marie Curie Program from EU (FP7-PEOPLE-
2013-CIG 631171)., Peer Reviewed

The most frequent rearrangement of the human MLL gene fuses MLL to AF4 resulting in high-risk infant B-cell acute lymphoblastic leukemia (B-ALL). MLL fusions are also hallmark oncogenic events in secondary acute myeloid leukemia. They are a direct consequence of mis-repaired DNA double strand breaks (DNA-DSBs) due to defects in the DNA damage response associated with exposure to topoisomerase- II poisons such as etoposide. It has been suggested that MLL fusions render cells susceptible to additional chromosomal damage upon exposure to etoposide. Conversely, the genome-wide mutational landscape in MLL-rearranged infant B-ALL has been reported silent. Thus, whether MLL fusions compromise the recognition and/or repair of DNA damage remains unanswered. Here, the fusion proteins MLL-AF4 (MA4) and AF4-MLL (A4M) were CRISPR/Cas9-genome edited in the AAVS1 locus of HEK293 cells as a model to study MLL fusion-mediated DNA-DSB formation/repair. Repair kinetics of etoposide- and ionizing radiation-induced DSBs was identical in WT, MA4- and A4M-expressing cells, as revealed by flow cytometry, by immunoblot for γH2AX and by comet assay. Accordingly, no differences were observed between WT, MA4- and A4M-expressing cells in the presence of master proteins involved in non-homologous end-joining (NHEJ; i.e.KU86, KU70), alternative-NHEJ (Alt-NHEJ; i.e.LigIIIa, WRN and PARP1), and homologous recombination (HR, i.e.RAD51). Moreover, functional assays revealed identical NHEJ and HR efficiency irrespective of the genotype. Treatment with etoposide consistently induced cell cycle arrest in S/G2/M independent of MA4/A4M expression, revealing a proper activation of the DNA damage checkpoints. Collectively, expression of MA4 or A4M does neither influence DNA signaling nor DNA-DSB repair., This work was supported by the European Research Council to P.M (ERC-2014-CoG-646903), MINECO (SAF2013-43065 to P.M), The Foundation Inocente Inocente and the Spanish Association of Cancer Research (AECC) to P.M and the Deutsche José Carreras Leukämie Stiftung to R.M/P.M. P.M also acknowledges the financial support from The Obra Social La Caixa-Fundaciò Josep Carreras and The Generalitat de Catalunya (SGR330). F.G. is supported by a Ramón y Cajal Grant (RYC-2014-16751) from the Ministry of Economy and Competitiveness (MINECO), Spain. N.C.G and A.B.H acknowledge financial support from The Cooperative Research Thematic Networks (RTICC) (RD12/0036/0058) and the INNOCAMPUS Program (CEI10-1-0010)., Peer Reviewed

Genetically modifying autologous T cells to express an anti-CD19 chimeric antigen receptor (CAR) has shown impressive response rates for the treatment of CD19+ B cell malignancies in several clinical trials (CTs). Making this treatment available to our patients prompted us to develop a novel CART19 based on our own anti-CD19 antibody (A3B1), followed by CD8 hinge and transmembrane region, 4-1BB- and CD3z-signaling domains. We show that A3B1 CAR T cells are highly cytotoxic and specific against CD19+ cells in vitro, inducing secretion of pro-inflammatory cytokines and CAR T cell proliferation. In vivo, A3B1 CAR T cells are able to fully control disease progression in an NOD.Cg-Prkdcscid Il2rdtm1Wjl/SzJ (NSG) xenograph B-ALL mouse model. Based on the pre-clinical data, we conclude that our CART19 is clearly functional against CD19+ cells, to a level similar to other CAR19s currently being used in the clinic. Concurrently, we describe the implementation of our CAR T cell production system, using lentiviral vector and CliniMACS Prodigy, within a medium-sized academic institution. The results of the validation phase show our system is robust and reproducible, while maintaining a low cost that is affordable for academic institutions. Our model can serve as a paradigm for similar institutions, and it may help to make CAR T cell treatment available to all patients.

CD38 is expressed in several types of non-Hodgkin lymphoma and constitutes a promising target for antibody-based therapy. Daratumumab (Darzalex) is a first-in-class anti-CD38 antibody approved for the treatment of relapsed/refractory multiple myeloma. It has also demonstrated clinical activity in Waldenstrom macroglobulinaemia and amyloidosis. Here, we have evaluated the activity and mechanism of action of daratumumab in preclinical in vitro and in vivo models of mantle cell lymphoma, follicular lymphoma and diffuse large B cell lymphoma, as monotherapy or in combination with standard chemo-immunotherapy. In vitro, daratumumab engages Fc-mediated cytotoxicity by antibody-dependent cell cytotoxicity and antibody-dependent cell phagocytosis in all lymphoma subtypes. In the presence of human serum, complement-dependent cell cytotoxicity was marginally engaged. We demonstrated by Selective Plane Illumination Microscopy that daratumumab fully penetrated a 3D lymphoma organoid and decreased organoid volume. In vivo, daratumumab completely prevents tumor outgrowth in models of mantle cell and follicular lymphoma, and shows comparable activity to rituximab in a disseminated in vivo model of blastic mantle cell lymphoma. Moreover, daratumumab improves overall survival in a mouse model of transformed CD20dim follicular lymphoma, where rituximab showed limited activity. Daratumumab potentiates the antitumor activity of CHOP and R-CHOP in mantle cell and follicular lymphoma xenografts. Furthermore, in a patient-derived diffuse large B cell lymphoma xenograft model, daratumumab anti-tumor activity was comparable to R-CHOP and the addition of daratumumab to either CHOP or R-CHOP led to full tumor regression. In summary, daratumumab constitutes a novel therapeutic opportunity in certain scenarios and these results warrant further clinical development.

In vertebrates, GATA2 is a master regulator of hematopoiesis and is expressed throughout embryo development and in adult life. Although the essential role of GATA2 in mouse hematopoiesis is well established, its involvement during early human hematopoietic development is not clear. By combining time-controlled overexpression of GATA2 with genetic knockout experiments, we found that GATA2, at the mesoderm specification stage, promotes the generation of hemogenic endothelial progenitors and their further differentiation to hematopoietic progenitor cells, and negatively regulates cardiac differentiation. Surprisingly, genome-wide transcriptional and chromatin immunoprecipitation analysis showed that GATA2 bound to regulatory regions, and repressed the expression of cardiac development-related genes. Moreover, genes important for hematopoietic differentiation were upregulated by GATA2 in a mostly indirect manner. Collectively, our data reveal a hitherto unrecognized role of GATA2 as a repressor of cardiac fates, and highlight the importance of coordinating the specification and repression of alternative cell fates.

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death.

Induced pluripotent stem cells (iPSCs) are a powerful tool for disease modeling. They are routinely generated from healthy donors and patients from multiple cell types at different developmental stages. However, reprogramming leukemias is an extremely inefficient process. Few studies generated iPSCs from primary chronic myeloid leukemias, but iPSC generation from acute myeloid or lymphoid leukemias (ALL) has not been achieved. We attempted to generate iPSCs from different subtypes of B-ALL to address the developmental impact of leukemic fusion genes. OKSM(L)-expressing mono/polycistronic-, retroviral/lentiviral/episomal-, and Sendai virus vector-based reprogramming strategies failed to render iPSCs in vitro and in vivo. Addition of transcriptomic-epigenetic reprogramming 'boosters' also failed to generate iPSCs from B cell blasts and B-ALL lines, and when iPSCs emerged they lacked leukemic fusion genes, demonstrating non-leukemic myeloid origin. Conversely, MLL-AF4-overexpressing hematopoietic stem cells/B progenitors were successfully reprogrammed, indicating that B cell origin and leukemic fusion gene were not reprogramming barriers. Global transcriptome/DNA methylome profiling suggested a developmental/differentiation refractoriness of MLL-rearranged B-ALL to reprogramming into pluripotency.

Recent studies in zebrafish and mice have revealed that proinflammatory signaling is a positive regulator of definitive hematopoietic development. Whether proinflammatory signaling also regulates human hematopoietic specification remains unknown. Here, we explored the impact of the proinflammatory cytokines tumor necrosis factor-α (TNFα), interferon-γ (IFNγ), and interleukin-1β (IL1β) on in vitro hematopoietic differentiation using human pluripotent stem cells. Gene expression analysis and enzyme-linked immunosorbent assay revealed the absence of a proinflammatory signature during hematopoietic development of human pluripotent stem cells. Functionally, the emergence of hemogenic endothelial progenitors (CD31+CD34+CD45− or CD34+CD43−CD73−) and hematopoietic cells (CD43+CD45+) was not affected by treatment with increasing doses of TNFα, IFNγ, and IL1β irrespective of the developmental window or the differentiation protocol used (embryoid body or OP9 co-culture based). Similarly, knockdown of endogenous NF-kB signaling had no impact on hematopoietic differentiation of human pluripotent stem cells. This study serves as a demonstration that TNFα, IFNγ, and IL1β signals do not improve hematopoietic differentiation of human pluripotent stem cells using current protocols and suggests that proinflammatory signaling is insufficient to drive definitive hematopoietic specification of human hematopoietic stem cells in vitro.