| 1. |
- Cozzi, Elisabetta, et al.
(författare)
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Identification of long non-coding RNAs involved in leukemogenesis and venetoclax response in acute myeloid leukemia through functional CRISPR-dCas9 interference screens
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Acute myeloid leukemia (AML) is a malignant hematologic disease with poor prognosis. Increased understanding of disease biology is therefore needed to improve outcome for patients. While the protein-coding genome is well characterized in AML, knowledge about the involvement of non-coding genes is very limited in AML. Here, it was sought to investigate how long non-coding RNAs (lncRNAs) could contribute to disease biology and treatment resistance in AML. Three high-throughput lncRNA-CRISPR-interference screens were performed in MOLM-13 cells, knocking down about 8000 lncRNA expressed in hematopoietic cells. Effects on cell proliferation, cell differentiation and response to the anti-leukemic Bcl-2-inhibitor venetoclax were investigated upon lncRNA repression. LncRNAs most likely to positively or negatively regulate these processes were identified and top lncRNA candidates investigated with respect to expression in AML and healthy CD34+ cells and clinical AML correlations. Four lncRNAs involved in AML cell proliferation were identified (lncRNAs MIR17HG, CATG00000056335, CATG00000095269, CATG00000002239), two lncRNAs involved in differentiation (lncRNAs RP11-444A22.1, CATG00000058672) and seven lncRNAs implicated in venetoclax response. Among those, enhanced expression of proliferation-promoting lncRNA MIR17HG significantly correlated with poor outcome in AML patients (p= 0.03; p= 0.016). Further, lncRNA RP11-444A2 was identified as a predicted negative regulator of cell differentiation and was found to correlate with poor outcome (p=0.014). Further, lncRNA AC009299.3, predicted in venetoclax sensitivity, was found to be associated with poor outcome (p<0.0001), adverse risk (p=0.0014) and increased age (p=0.0045) in AML patients. Together, this study identified 14 lncRNAs proposed to be implicated in key leukemogenic events, highlighting their potential for elucidating AML biology, prognosis or treatment-response prediction and/or therapeutic use.
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| 2. |
- Mareschal, Sylvain, et al.
(författare)
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Challenging conventional karyotyping by next-generation karyotyping in 281 intensively treated patients with AML
- 2021
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 5:4, s. 1003-1016
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Tidskriftsartikel (refereegranskat)abstract
- Although copy number alterations (CNAs) and translocations constitute the backbone of the diagnosis and prognostication of acute myeloid leukemia (AML), techniques used for their assessment in routine diagnostics have not been reconsidered for decades. We used a combination of 2 next-generation sequencing-based techniques to challenge the currently recommended conventional cytogenetic analysis (CCA), comparing the approaches in a series of 281 intensively treated patients with AML. Shallow whole-genome sequencing (sWGS) outperformed CCA in detecting European Leukemia Net (ELN)-defining CNAs and showed that CCA overestimated monosomies and suboptimally reported karyotype complexity. Still, the concordance between CCA and sWGS for all ELN CNA-related criteria was 94%. Moreover, using in silico dilution, we showed that 1 million reads per patient would be enough to accurately assess ELN-defining CNAs. Total genomic loss, defined as a total loss 200 Mb by sWGS, was found to be a better marker for genetic complexity and poor prognosis compared with the CCA-based definition of complex karyotype. For fusion detection, the concordance between CCA and whole-transcriptome sequencing (WTS) was 99%. WTS had better sensitivity in identifying inv(16) and KMT2A rearrangements while showing limitations in detecting lowly expressed PML-RARA fusions. Ligation-dependent reverse transcription polymerase chain reaction was used for validation and was shown to be a fast and reliable method for fusion detection. We conclude that a next-generation sequencing-based approach can replace conventional CCA for karyotyping, provided that efforts are made to cover lowly expressed fusion transcripts.
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| 3. |
- Miliara, Sophia, et al.
(författare)
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The biological and prognostic role of long non-coding RNA NEAT1 in acute myeloid leukemia
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Nuclear paraspeckle assembly transcript 1 (NEAT1) is a long non-coding RNA localized in the cell nucleus that has been associated to promote several malignant solid tumors. Its role in acute myeloid leukemia (AML) remains largely elusive. Therefore, the aim of this study was to define the role of NEAT1 in AML compared to normal hematopoiesis. During normal hematopoiesis, it was identified that NEAT1 expression was low in early progenitors but increased in more differentiated cells, especially in monocytes. NEAT1 expression was increased in AML as a whole compared to normal bone marrow (NBM). It was specifically high in AML with inv(16) and t(8;21), while it was lower in patients with t(15;17). Further, NEAT1 expression correlated positively with ASXL1, KRAS and NRAS mutations and negatively with TP53 mutant AML. Higher NEAT expression was associated to better overall survival in AML, independent of other known risk factors. Antisense oligo-mediated knockdown of NEAT1 in AML cells significantly increased expression of the monocytic marker CD14 while granulocytic markers did not change. Genes affected by NEAT1-knockdown using CAGE-sequencing were significantly enriched for genes involved in glucose metabolism. By investigating genome-wide RNA and DNA interactions using RADICL-sequencing, it was revealed that NEAT1 binds to the loci of key hematopoietic regulator RUNX2 as well as the chromatin regulators KMT2A, KMT5B and CHD7. The results suggest that lncRNA NEAT1 has a potential role in hematopoietic and AML cell differentiation and could be a potential new biomarker in AML.
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| 4. |
- Mujahed, Huthayfa, et al.
(författare)
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AML displays increased CTCF occupancy associated with aberrant gene expression and transcription factor binding
- 2020
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 136:3, s. 339-352
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Tidskriftsartikel (refereegranskat)abstract
- CCTC-binding factor (CTCF) is a key regulator of gene expression through organization of the chromatin structure. Still, it is unclear how CTCF binding is perturbed in leukemia or in cancer in general. We studied CTCF binding by chromatin immunoprecipitation sequencing in cells from patients with acute myeloid leukemia (AML) and in normal bone marrow (NBM) in the context of gene expression, DNA methylation, and azacitidine exposure. CTCF binding was increased in AML compared with NBM. Aberrant CTCF binding was enriched for motifs for key myeloid transcription factors such as CEBPA, PU.1, and RUNX1. AML with TET2 mutations was characterized by a particularly strong gain of CTCF binding, highly enriched for gain in promoter regions, while AML in general was enriched for changes at enhancers. There was a strong anticorrelation between CTCF binding and DNA methylation. Gain of CTCF occupancy was associated with increased gene expression; however, the genomic location (promoter vs distal regions) and enrichment of motifs (for repressing vs activating cofactors) were decisive for the gene expression pattern. Knockdown of CTCF in K562 cells caused loss of CTCF binding and transcriptional repression of genes with changed CTCF binding in AML, as well as loss of RUNX1 binding at RUNX1/CTCF-binding sites. In addition, CTCF knockdown caused increased differentiation. Azacitidine exposure caused major changes in CTCF occupancy in AML patient cells, partly by restoring a CTCF-binding pattern similar to NBM. We conclude that AML displays an aberrant increase in CTCF occupancy that targets key genes for AML development and impacts gene expression.
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| 5. |
- Neddermeyer, Anne, et al.
(författare)
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A new mutant NPM1/IDH2R140- and PML-RARA-associated lncRNA MALNC plays a role in AML biology, prognosis and drug response
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by poor prognosis that requires better understanding of its disease biology and new tools for suitable risk stratification and effective treatments. Long non-coding RNAs (lncRNAs) are involved in numerous molecular mechanisms, are implicated in tumor biology and can serve as clinical biomarkers, yet their role remains mostly unclear in AML. In this study, the aim was to discover and characterize lncRNAs implicated in AML and to describe their role in AML biology. Further aims were to explore their use as prognostic or predictive biomarkers. Using whole-transcriptome analysis, a novel lncRNA, here named MALNC, was identified. MALNC had elevated expression in two large AML cohorts compared to normal CD34+ cells. Clinical correlation analyses indicated that MALNC was almost uniquely expressed in patients with PML-RARA fusion gene and with co-mutated isocitrate dehydrogenase-2 R140 and nucleophosmin-1 (IDH2R140/NPM1). MALNC expression was specifically high at the promyelocytic stage and decreased with maturation in leukemic and normal cells. High MALNC expression associated independently with better overall survival. CRISPR-Cas9-knockout in promyelocytic cell lines impaired proliferation, colony formation and all-trans retinoic acid (ATRA)-induced differentiation. Also, MALNC-knockout dramatically sensitized cells to arsenic trioxide (ATO), ATO-ATRA combinatorial and Bcl-2-inhibitor venetoclax treatment as well as associated with cyclin-dependent kinase (Cdk)-inhibitor resistance. In conclusion, MALNC is overexpressed in certain subgroups of AML and could play a role during normal and leukemic hematopoietic maturation. Furthermore, it correlates with response to anti-leukemic drugs, which suggests a role as a predictive marker to drug response and survival in AML.
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| 6. |
- Neddermeyer, Anne H.
(författare)
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Identification and Functional Significance of Aberrant Long Non-coding RNAs in Acute Myeloid Leukemia : Biological and Prognostic Implications
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Acute myeloid leukemia (AML) is the most frequently diagnosed type of acute leukemia in adults. It commonly affects people aged 60 or older, as incidence increases with age, and it is characterized by the accumulation of immature hematopoietic progenitor cells in the bone marrow. Despite recent treatment advances and improvements for certain subtypes, as acute promyelocyte leukemia (APL), AML remains difficult to cure. While many patients reach remission after induction treatment, relapses are common and 5-year overall survival remains dismal. Long non-coding RNAs (lncRNAs) are involved in various regulatory cellular functions and, like coding genes, they are frequently dysregulated in cancer. In this thesis, the aim was to elucidate the functional implications of lncRNAs in the biology and treatment response of AML and normal hematopoiesis in order to improve understanding of AML pathology. In Paper I, whole-transcriptome sequencing identified the novel lncRNA MALNC. Clinical correlation analyses and CRISPR-knockout cell models were used to functionally explore its implications in AML. It was identified that enhanced MALNC expression is specifically associated with the AML-subtypes APL and AML with co-mutant NPM1/IDH2R140. Further, it was shown that MALNC is implicated in key factors of leukemogenesis, like differentiation and proliferation, and that MALNC expression associates with better overall survival in AML patients. Moreover, knockout of the MALNC gene sensitized AML cells to arsenic trioxide (ATO), all-trans retinoic acid (ATRA)-ATO combination and venetoclax treatment. In Paper II, three high-throughput functional CRISPR interference screens were performed to identify lncRNAs implicated in proliferation, differentiation or venetoclax response. Several novel lncRNAs were identified to potentially play a positive or negative role in these processes and furthermore were found to implicate AML prognosis. In Paper III, the lncRNA NEAT1 was studied in respect to its role in normal hematopoiesis and AML using CAGE- and RADICL-sequencing. It could be illustrated that NEAT1 expression positively correlates with cell maturity during normal hematopoiesis, in particular monocytes, and associates with core-binding factor AML inv(16) and t(8;21). Further, RADICL-sequencing identified that lncRNA NEAT1 binds to the genomic loci of key hematopoietic transcription factor RUNX2. In contrast to solid cancers, it was demonstrated, that higher NEAT1 expression correlated with better outcome in AML, independent of known risk factors. In summary, these studies have outlined the scope of functional implications of lncRNAs in normal and dysregulated hematopoiesis and have highlighted their potential roles as biomarkers for prognosis and drug sensitivity. These findings support the efforts to understand how lncRNAs could serve as novel biomarkers for personalized treatment.
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| 7. |
- Neddermeyer, Anne H., et al.
(författare)
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Investigating Tick-borne Flaviviral-like Particles as a Delivery System for Gene Therapy
- 2018
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Ingår i: Current Therapeutic Research. - : ELSEVIER SCIENCE INC. - 0011-393X .- 1879-0313. ; 88, s. 8-17
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Tidskriftsartikel (refereegranskat)abstract
- Background: Research on the biogenesis of tick-borne encephalitis virus (TBEV) would benefit gene therapy. Due to specific arrangements of genes along the TBEV genome, its viral-like particles (VLPs) could be exploited as shuttles to deliver their replicon, which carries therapeutic genes, to immune system cells.Objective: To develop a flaviviral vector for gene delivery as a part of gene therapy research that can be expressed in secretable VLP suicidal shuttles and provide abundant unique molecular and structural data supporting this gene therapy concept.Method: TBEV structural gene constructs of a Swedish Torö strain were cloned into plasmids driven by the promoters CAG and CMV and then transfected into various cell lines, including COS-1 and BHK-21. Time-course sampling of the cells, culture fluid, cell lysate supernatant, and pellet specimens were performed. Western blotting and electron microscopy analyses of collected specimens were used to investigate molecular and structural processing of TBEV structural proteins.Results: Western blotting analysis showed differences between promoters in directing the gene expression of the VLPs constructs. The premature flaviviral polypeptides as well as mature VLPs could be traced. Using electron microscopy, the premature and mature VLP accumulation in cellular compartments—and also endoplasmic reticulum proliferation as a virus factory platform—were observed in addition to secreted VLPs.Conclusions: The abundant virologic and cellular findings in this study show the natural processing and safety of inserting flaviviral structural genes into suicidal VLP shuttles. Thus, we propose that these VLPs are a suitable gene delivering system model in gene therapy.
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