CRISPR-ERA for Switching Off (Onco) Genes

Genome-editing nucleases like the popular CRISPR/Cas9 enable the generation of knockout cell lines and null zygotes by inducing site-specific double-stranded breaks (DSBs) within a genome. In most cases, when a DNA template is not present, the DSB is repaired by nonhomologous end joining (NHEJ), resulting in small nucleotide insertions or deletions that can be used to construct knockout alleles. However, for several reasons, these mutations do not produce the desired null result in all cases, instead generating a similar protein with functional activity. This undesirable effect could limit the therapeutic efficiency of gene therapy strategies focused on abrogating oncogene expression by CRISPR/Cas9 and should be taken into account. This chapter reviews the irruption of CRISPR technology for gene silencing and its application in gene therapy

TET2 overexpression in chronic lymphocytic leukemia is unrelated to the presence of TET2 variations

This is an open access article distributed under the Creative Commons Attribution License.TET2 is involved in a variety of hematopoietic malignancies, mainly in myeloid malignancies. Most mutations of TET2 have been identified in myeloid disorders, but some have also recently been described in mature lymphoid neoplasms. In contrast to the large amount of data about mutations of TET2, some data are available for gene expression. Moreover, the role of TET2 in chronic lymphocytic leukemia (CLL) is unknown. This study analyzes both TET2 expression and mutations in 48 CLL patients. TET2 expression was analyzed by exon arrays and quantitative real-time polymerase chain reaction (qRT-PCR). Next-generation sequencing (NGS) technology was applied to investigate the presence of TET2 variations. Overexpression of TET2 was observed in B-cell lymphocytes from CLL patients compared with healthy donors (P = 0.004). In addition, in CLL patients, an overexpression of TET2 was also observed in the clonal B cells compared with the nontumoral cells (P = 0.002). However, no novel mutations were observed. Therefore, overexpression of TET2 in CLL seems to be unrelated to the presence of genomic TET2 variations.This work was partially supported by Grants from the Spanish Fondo de Investigaciones Sanitarias FIS 09/01543, PI12/00281, Proyectos de Investigacion del SACYL 355/A/09, COST Action “EuGESMA” (BM0801), Fundación “Manuel Solorzano,” Obra Social Banca Cívica (Caja Burgos), Fundacion Española de Hematología y Hemoterapia (FEHH), and by a Grant (RD12/0036/0069) from Red Temática de Investigación Cooperativa en Cáncer (RTICC), Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Economy and Competitiveness and European Regional Development Fund (ERDF) “Una manera de hacer Europa”, and NGS-PTL no. 306242. Maríıa Hernandez-Sánchez is fully suported by an “Ayuda predoctoral de la Junta de Castilla y Leon” by the “Fondo Social Europeo.”Peer Reviewe

Two novel variants of the ABCG5 gene cause xanthelasmas and macrothrombocytopenia: a brief review of hematologic abnormalities of sitosterolemia

[EN] Background: Sitosterolemia (STSL) is a recessive inherited disorder caused by pathogenic variants in the ABCG5 and ABCG8 genes. Increased levels of plasma plant sterols (PSs) usually result in xanthomas and premature coronary atherosclerosis, although hematologic abnormalities may occasionally be present. This clinical picture is unfamiliar to many physicians, and patients may be at high risk of misdiagnosis. Objectives: To report two novel ABCG5 variants causing STSL in a Spanish patient, and review the clinical and mutational landscape of STSL. Patient/Methods: A 46-year-old female was referred to us with lifelong macrothrombocytopenia. She showed familial hypercholesterolemia-related xanthomas. Molecular analysis was performed with high-throughput sequencing. Plasma PS levels were evaluated with gas–liquid chromatography. The STSL landscape was reviewed with respect to specific online databases and all reports published since 1974. Results: A blood smear revealed giant platelets and stomatocytes. Novel compound heterozygous variants were detected in exons 7 (c.914C>G) and 13 (c.1890delT) of ABCG5. The patient showed an increased plasma level of sitosterol. These findings support the diagnosis of STSL. In our review, we identified only 25 unrelated STLS patients who presented with hematologic abnormalities including macrothrombocytopenia

Trophic models and short-term dynamic simulations for benthic-pelagic communities at Banco Chinchorro Biosphere Reserve (Mexican Caribbean): a conservation case

Banco Chinchorro is the largest reef in the Mexican Caribbean. Historically, spiny lobster, queen conch and over 20 other reef species have been exploited here. Multispecies intervention management from an ecosystem perspective has been developed in this area; however, an assessment of the effects of such practices on ecosystem health is required. Five quantitative trophic models were constructed using Ecopath with Ecosim. The results show that, in terms of biomass, benthic autotrophs are the dominant group in all communities. Ecosystem Network Analysis indices showed that Cueva de Tiburones was the most mature, developed, complex and healthy subsystem, but, El Colorado and La Baliza were the subsystems most resistant to disturbances. The fisheries mainly concentrate on primary (La Baliza and Cueva de Tiburones sites) and secondary consumers (La Caldera, Chancay, and El Colorado). The greatest propagation of direct and indirect effects, estimated by Mixed Trophic Impacts and Ecosim simulations, were generated by the benthic autotrophs, small benthic epifauna, benthic-pelagic carnivorous fish and benthic carnivorous fish, among others. In contrast, the System Recovery Time showed different patterns among subsystems, indicating several compartments that reduce resilience. Considering the structure, dynamics, trophic functioning and ecosystem health of Banco Chinchorro, its ecological heterogeneity highlights the need for the design of a specific (by subsystem) management strategy, particularly because different species or functional groups present greater sensitivity to human interventions in each community

Imatinib therapy of chronic myeloid leukemia restores the expression levels of key genes for DNA damage and cell-cycle progression

[EN] Background Chronic myeloid leukemia (CML) is a malignant clonal disorder of the hematopoietic system caused by the expression of the BCR/ABL fusion oncogene. It is well known that CML cells are genetically unstable. However, the mechanisms by which these cells acquire genetic alterations are poorly understood. Imatinib mesylate is the standard therapy for newly diagnosed CML patients. Imatinib mesylate targets the oncogenic kinase activity of BCR-ABL. Objective To study the gene expression profile of bone marrow hematopoietic cells in the same patients with CML before and 1 month after imatinib therapy. Methods Samples from patients with CML were analyzed using Affymetrix GeneChip Expression Arrays. Results A total of 594 differentially expressed genes, most of which (393 genes) were downregulated, as a result of imatinib therapy were observed. Conclusion The blockade of oncoprotein Bcr-Abl by imatinib could cause a decrease in the expression of key DNA repair genes and substantially modify the expression profile of the bone marrow cells in the first days of therapy

TRAF3 alterations are frequent in del-3′IGH chronic lymphocytic leukemia patients and define a specific subgroup with adverse clinical features

Interstitial 14q32 deletions involving IGH gene are infrequent events in chronic lymphocytic leukemia (CLL), affecting less than 5% of patients. To date, little is known about their clinical impact and molecular underpinnings, and its mutational landscape is currently unknown. In this work, a total of 871 CLLs were tested for the IGH break-apart probe, and 54 (6.2%) had a 300 kb deletion of 3′IGH (del-3′IGH CLLs), which contributed to a shorter time to first treatment (TFT). The mutational analysis by next-generation sequencing of 317 untreated CLLs (54 del-3′IGH and 263 as the control group) showed high mutational frequencies of NOTCH1 (30%), ATM (20%), genes involved in the RAS signaling pathway (BRAF, KRAS, NRAS, and MAP2K1) (15%), and TRAF3 (13%) within del-3′IGH CLLs. Notably, the incidence of TRAF3 mutations was significantly higher in del-3′IGH CLLs than in the control group (p < .001). Copy number analysis also revealed that TRAF3 loss was highly enriched in CLLs with 14q deletion (p < .001), indicating a complete biallelic inactivation of this gene through deletion and mutation. Interestingly, the presence of mutations in the aforementioned genes negatively refined the prognosis of del-3′IGH CLLs in terms of overall survival (NOTCH1, ATM, and RAS signaling pathway genes) and TFT (TRAF3). Furthermore, TRAF3 biallelic inactivation constituted an independent risk factor for TFT in the entire CLL cohort. Altogether, our work demonstrates the distinct genetic landscape of del-3′IGH CLL with multiple molecular pathways affected, characterized by a TRAF3 biallelic inactivation that contributes to a marked poor outcome in this subgroup of patients.Funding information: Universidad de Salamanca; Fundación Española de Hematología y Hemoterapia (FEHH); Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Grant/Award Number: CB16/12/00233; Red Temática de Investigación Cooperativa en Cáncer (RTICC); “Fundación Memoria Don Samuel Solórzano Barruso”: FS/33–2020, Grant/Award Number: RD12/0036/0069; “Gerencia Regional de Salud, SACYL”:, Grant/Award Numbers: GRS2385/A/21, GRS2140/A/20; Consejería de Educación, Junta de Castilla y León, Grant/Award Number: SA118P20; European Regional Development Fund and Instituto de Salud Carlos III, Grant/Award Numbers: CD19/00222, FI19/00191; Spanish Fondo de Investigaciones Sanitarias, Grant/Award Numbers: PI21/00983, PI18/0150

Biological significance of monoallelic and biallelic BIRC3 loss in del(11q) chronic lymphocytic leukemia progression

© The Author(s) 2021.BIRC3 is monoallelically deleted in up to 80% of chronic lymphocytic leukemia (CLL) cases harboring del(11q). In addition, truncating mutations in the remaining allele of this gene can lead to BIRC3 biallelic inactivation, which has been shown to be a marker for reduced survival in CLL. Nevertheless, the biological mechanisms by which these lesions could contribute to del(11q) CLL pathogenesis and progression are partially unexplored. We implemented the CRISPR/Cas9-editing system to generate isogenic CLL cell lines harboring del(11q) and/or BIRC3 mutations, modeling monoallelic and biallelic BIRC3 loss. Our results reveal that monoallelic BIRC3 deletion in del(11q) cells promotes non-canonical NF-κB signaling activation via RelB-p52 nuclear translocation, being these effects allelic dose-dependent and therefore further enhanced in del(11q) cells with biallelic BIRC3 loss. Moreover, we demonstrate ex vivo in primary cells that del(11q) cases including BIRC3 within their deleted region show evidence of non-canonical NF-κB activation which correlates with high BCL2 levels and enhanced sensitivity to venetoclax. Furthermore, our results show that BIRC3 mutations in del(11q) cells promote clonal advantage in vitro and accelerate leukemic progression in an in vivo xenograft model. Altogether, this work highlights the biological bases underlying disease progression of del(11q) CLL patients harboring BIRC3 deletion and mutation.This work was supported by grants from the Spanish Fondo de Investigaciones Sanitarias PI15/01471, PI18/01500, Instituto de Salud Carlos III (ISCIII), European Regional Development Fund (ERDF) “Una manera de hacer Europa”, “Consejería de Educación, Junta de Castilla y León” (SA271P18), “Proyectos de Investigación del SACYL”, Spain GRS 2062/A/19, GRS 1847/A/18, GRS1653/A17,“Fundación Memoria Don Samuel Solórzano Barruso” (FS/23-2018), by grants (RD12/0036/0069) from Red Temática de Investigación Cooperativa en Cáncer (RTICC), Universidad de Salamanca (Programa XIII), Centro de Investigación Biomédica en Red de Cáncer (CIBERONC CB16/12/00233) and SYNtherapy “Synthetic Lethality for Personalized Therapy-based Stratification In Acute Leukemia” (ERAPERMED2018-275); ISCIII (AC18/00093), co-funded by ERDF/ESF, “Investing in your future”. M.Q.Á. and A.E.R.V. are supported with a research grant by FEHH (“Fundación Española de Hematología y Hemoterapia”); M.H.S. holds a Sara Borrell postdoctoral contract (CD19/00222) from the Instituto de Salud Carlos III (ISCIII). C.P.C. was supported by an “Ayuda predoctoral en Oncología” (AECC) and is a recipient of a PFIS grant (FI19/00191) from Instituto de Salud Carlos III; PFIS grant and Sara Borrell postdoctoral contrat are co-founded by Fondo Social Europeo (FSE) “El Fondo Social Europeo invierte en tu futuro”; J.L.O. and R.B.S. are supported by a grant from the University of Salamanca (“Contrato postdoctoral programa II”)

Cytogenetic and genomic analysis of a patient with turner syndrome and t(2;12): a case report

Background: Turner syndrome is a genetic disorder that afects women. It is caused by an absent or incomplete X chromosome, which can be presented in mosaicism or not. There are 12 cases of Turner syndrome patients who present structural alterations in autosomal chromosomes. Case presentation: The present case report describes a patient with a reciprocal, maternally inherited translocation between chromosomes 2 and 12 with a mosaicism of X monosomy 45,X,t(2;12)(p13;q24)[95]/46,XX,t(2;12)(p13;q24) [5]. Through genetic mapping arrays, altered genes in the patient were determined within the 23 chromosome pairs. These genes were associated with the patient’s clinical features using a bioinformatics tool Conclusion: To our knowledge, this is the frst case in which a translocation (2;12) is reported in a patient with Turner syndrome and confrmed by conventional cytogenetics, FISH and molecular genetics. Clinical features of our patient are closely related with the loss of one X chromosome, however mild intellectual disability can be likely explained by autosomal genes. The presence of familial translocations was a common fnding, thus emphasizing the need for familiar testing for further genetic counselling

Core outcome set measurement for future clinical trials in acute myeloid leukemia: the HARMONY study protocol using a multi-stakeholder consensus-based Delphi process and a final consensus meeting

Abstract: Background: Acute myeloid leukemia (AML) is the most common acute leukemia in adults and has an unacceptably low cure rate. In recent years, a number of new treatment strategies and compounds were developed for the treatment of AML. There were several randomized controlled clinical trials with the objective to improve patients’ management and patients’ outcome in AML. Unfortunately, these trials are not always directly comparable since they do not measure the same outcomes, and currently there are no core outcome sets that can be used to guide outcome selection and harmonization in this disease area. The HARMONY (Healthcare Alliance for Resourceful Medicine Offensive against Neoplasms in Hematology) Alliance is a public-private European network established in 2017 and currently includes 53 partners and 32 associated members from 22 countries. Amongst many other goals of the HARMONY Alliance, Work Package 2 focuses on defining outcomes that are relevant to each hematological malignancy. Accordingly, this pilot study will be performed to define a core outcome set in AML. Methods: The pilot study will use a three-round Delphi survey and a final consensus meeting to define a core outcome set. Participants will be recruited from different stakeholder groups, including patients, clinicians, regulators and members of the European Federation of Pharmaceutical Industries and Associations. At the pre-Delphi stage, a literature research was conducted followed by several semi-structured interviews of clinical public and private key opinion leaders. Subsequently, the preliminary outcome list was discussed in several multi-stakeholder face-to-face meetings. The Delphi survey will reduce the preliminary outcome list to essential core outcomes. After completion of the last Delphi round, a final face-to-face meeting is planned to achieve consensus about the core outcome set in AML. Discussion: As part of the HARMONY Alliance, the pilot Delphi aims to define a core outcome set in AML on the basis of a multi-stakeholder consensus. Such a core outcome set will help to allow consistent comparison of future clinical trials and real-world evidence research and ensures that appropriate outcomes valued by a range of stakeholders are measured within future trials

Use of eltrombopag for patients 65 years old or older with immune thrombocytopenia

Background Eltrombopag is useful for immune thrombocytopenia (ITP). However, results of clinical trials may not accurately mirror clinical practice reality. Here we evaluated eltrombopag for primary and secondary ITP in our ≥65‐year‐old population. Methods A total of 106 primary ITP patients (16 with newly diagnosed ITP, 16 with persistent ITP, and 74 with chronic ITP) and 39 secondary ITP patients (20 with ITP secondary to immune disorders, 7 with ITP secondary to infectious diseases, and 12 with ITP secondary to lymphoproliferative disorders [LPD]) were retrospectively evaluated. Results Median age of our cohort was 76 (interquartile range, IQR, 70‐81) years. 75.9% of patients yielded a platelet response including 66.2% complete responders. Median time to platelet response was 14 (IQR, 8‐21) days. Median time on response was 320 (IQR, 147‐526) days. Sixty‐three adverse events (AEs), mainly grade 1‐2, occurred. The most common were hepatobiliary laboratory abnormalities (HBLAs) and headaches. One transient ischemic attack in a newly diagnosed ITP and two self‐limited pulmonary embolisms in secondary ITP were the only thrombotic events observed. Conclusion Eltrombopag showed efficacy and safety in ITP patients aged ≥65 years with primary and secondary ITP. However, efficacy results in LPD‐ITP were poor. A relatively high number of deaths were observed