| 1. |
- Hyrenius-Wittsten, Axel, et al.
(författare)
-
De novo activating mutations drive clonal evolution and enhance clonal fitness in KMT2A-rearranged leukemia
- 2018
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Activating signaling mutations are common in acute leukemia with KMT2A (previously MLL) rearrangements (KMT2A-R). These mutations are often subclonal and their biological impact remains unclear. Using a retroviral acute myeloid mouse leukemia model, we demonstrate that FLT3 ITD, FLT3 N676K, and NRAS G12D accelerate KMT2A-MLLT3 leukemia onset. Further, also subclonal FLT3 N676K mutations accelerate disease, possibly by providing stimulatory factors. Herein, we show that one such factor, MIF, promotes survival of mouse KMT2A-MLLT3 leukemia initiating cells. We identify acquired de novo mutations in Braf, Cbl, Kras, and Ptpn11 in KMT2A-MLLT3 leukemia cells that favored clonal expansion. During clonal evolution, we observe serial genetic changes at the Kras G12D locus, consistent with a strong selective advantage of additional Kras G12D . KMT2A-MLLT3 leukemias with signaling mutations enforce Myc and Myb transcriptional modules. Our results provide new insight into the biology of KMT2A-R leukemia with subclonal signaling mutations and highlight the importance of activated signaling as a contributing driver.
|
|
| 2. |
|
|
| 3. |
- Hyrenius-Wittsten, Axel, et al.
(författare)
-
Genomic profiling and directed ex vivo drug analysis of an unclassifiable myelodysplastic/myeloproliferative neoplasm progressing into acute myeloid leukemia
- 2016
-
Ingår i: Genes Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 55:11, s. 847-854
-
Tidskriftsartikel (refereegranskat)abstract
- Myelodysplastic/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U) are rare genetically heterogeneous hematologic diseases associated with older age and a poor prognosis. If the disease progresses into acute myeloid leukemia (AML), it is often refractory to treatment. To gain insight into genetic alterations associated with disease progression, whole exome sequencing and single nucleotide polymorphism arrays were used to characterize the bone marrow and blood samples from a 39-year-old woman at MDS/MPN-U diagnosis and at AML progression, in which routine genetic diagnostics had not identified any genetic alterations. The data revealed the presence of a partial tandem duplication of the MLL gene as the only detectable copy number change and 11 non-silent somatic mutations, including DNMT3A R882H and NRAS G13D. All somatic lesions were present both at initial MDS/MPN-U diagnosis and at AML presentation at similar mutant allele frequencies. The patient has since had two extramedullary relapses and is at high risk of a future bone marrow relapse. A directed ex vivo drug sensitivity analysis showed that the patient's AML cells are sensitive to, for example, the MEK inhibitor trametinib and the proteasome inhibitor bortezomib, indicating that she may benefit from treatment with these drugs.
|
|
| 4. |
- Hyrenius Wittsten, Axel
(författare)
-
Molecular Interrogation and Functional Studies of Acute Leukemia
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hematological malignancies are defined by their underlying genetic alterations, many of which are used to diagnose patients to classify them to different risk groups that dictate the therapy given. Recent advances in high-throughput sequencing have highlighted the presence of co-occurring genetic lesions and that they may form distinct genetic clones that evolve throughout disease progression. Acute leukemia is a group of diseases affecting either the lymphoid or myeloid lineage in hematopoiesis, resulting in acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML). Certain genetic alterations are closely tied to specific leukemia types, while others are more promiscuous. In this thesis, we have used high-resolution genome-wide methods and murine models to study leukemia as a way to increase our knowledge how leukemia arises and best can be treated.In the first study (Article I) we characterized the genetic alterations in a case presenting with a rare myelodysplatic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-U) that later progressed to AML. Through comprehensive analyses of the MDS/MPN-U and AML samples, we observed that all genetic lesions detected at AML diagnosis were present already at the MDS/MPN-U stage, likely in a similar clonal composition. Further, targeted drug analysis of the AML sample suggested clinically approved drugs from which the patient could benefit at a potential relapse.Genetic rearrangements of the epigenetic regulator KMT2A (KMT2A-R) often co-occur with activating mutations in genes involved in intracellular signaling. In the second study (Article II) we show that mutations in FLT3 and NRAS significantly accelerate KMT2A-R driven AML onset, even when present in a subclone as exemplified by the FLT3N676K mutation. The presence of an activating mutation affected the leukemias transcriptional profiles by further enhancing transcriptional programs previously associated with KMT2A-Rs. Genomic characterization of mouse leukemias unveiled de novo signaling mutations in several mice harboring only a KMT2A-R, emphasizing the importance of such mutations in KMT2A-R leukemogenesis. KMT2A-Rs occur in both ALL and AML but the molecular and/or biological mechanisms determining the lineage affiliation remain largely elusive for this disease. In the third study (Article III) we demonstrated the that FLT3N676K promote myeloid expansion of KMT2A-R leukemia in primary human cells. We further showed that established KMT2A-R ALL and AML cells displayed expression profiles closely linked to their respective lineage but that these cells still display a certain immunophenotypic plasticity.Previously, a large portion of pediatric B-cell precursor ALL (BCP-ALL) patients could not be classified to any of the established molecular subtypes. Chromosomal alterations are a hallmark of BCP-ALL and in the last study (Article IV) we employed high-throughput sequencing to define the fusion gene landscape of 195 pediatric BCP-ALL. Besides identifying several novel in-frame fusion genes, we also described two new oncogenic leukemia subtypes. These two subtypes were associated with distinct genetic lesions, including genetic rearrangements of the DUX4 gene and genetic alterations of ETV6 and IKZF1. Taken together, the work included in this thesis highlights the major impact that specific genetic alterations have on leukemogenesis, and how their autonomous and non-autonomous cooperation influence clonal evolution, disease phenotype, and molecular profiles of the leukemia.
|
|
| 5. |
- Lilljebjörn, Henrik, et al.
(författare)
-
Identification of ETV6-RUNX1-like and DUX4-rearranged subtypes in paediatric B-cell precursor acute lymphoblastic leukaemia
- 2016
-
Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11790
-
Tidskriftsartikel (refereegranskat)abstract
- Fusion genes are potent driver mutations in cancer. In this study, we delineate the fusion gene landscape in a consecutive series of 195 paediatric B-cell precursor acute lymphoblastic leukaemia (BCP ALL). Using RNA sequencing, we find in-frame fusion genes in 127 (65%) cases, including 27 novel fusions. We describe a subtype characterized by recurrent IGH-DUX4 or ERG-DUX4 fusions, representing 4% of cases, leading to overexpression of DUX4 and frequently co-occurring with intragenic ERG deletions. Furthermore, we identify a subtype characterized by an ETV6-RUNX1-like gene-expression profile and coexisting ETV6 and IKZF1 alterations. Thus, this study provides a detailed overview of fusion genes in paediatric BCP ALL and adds new pathogenetic insights, which may improve risk stratification and provide therapeutic options for this disease.
|
|
| 6. |
- Pilheden, Mattias, et al.
(författare)
-
Duplex sequencing uncovers recurrent low-frequency cancer-associated mutations in infant and childhood KMT2A-rearranged acute leukemia
- 2022
-
Ingår i: HemaSphere. - : Wolters Kluwer. - 2572-9241. ; 6:10
-
Tidskriftsartikel (refereegranskat)abstract
- Infant acute lymphoblastic leukemia (ALL) with KMT2A-gene rearrangements (KMT2A-r) have few mutations and a poor prognosis. To uncover mutations that are below the detection of standard next-generation sequencing (NGS), a combination of targeted duplex sequencing and NGS was applied on 20 infants and 7 children with KMT2A-r ALL, 5 longitudinal and 6 paired relapse samples. Of identified nonsynonymous mutations, 87 had been previously implicated in cancer and targeted genes recurrently altered in KMT2A-r leukemia and included mutations in KRAS, NRAS, FLT3, TP53, PIK3CA, PAX5, PIK3R1, and PTPN11, with infants having fewer such mutations. Of identified cancer-associated mutations, 62% were below the resolution of standard NGS. Only 33 of 87 mutations exceeded 2% of cellular prevalence and most-targeted PI3K/RAS genes (31/33) and typically KRAS/NRAS. Five patients only had low-frequency PI3K/RAS mutations without a higher-frequency signaling mutation. Further, drug-resistant clones with FLT3D835H or NRASG13D/G12S mutations that comprised only 0.06% to 0.34% of diagnostic cells, expanded at relapse. Finally, in longitudinal samples, the relapse clone persisted as a minor subclone from diagnosis and through treatment before expanding during the last month of disease. Together, we demonstrate that infant and childhood KMT2A-r ALL harbor low-frequency cancer-associated mutations, implying a vast subclonal genetic landscape.
|
|
| 7. |
- Svensson Birkedal, Gabriel, et al.
(författare)
-
The Structural Role of N-Linked Glycans on Human Glypican-1
- 2011
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 50:43, s. 9377-9387
-
Tidskriftsartikel (refereegranskat)abstract
- Glypicans are cell-surface heparan sulfate proteoglycans that regulate developmental signaling pathways by binding growth factors to their heparan sulfate chains. The primary structures of glypican core proteins contain potential N-glycosylation sites, but the importance of N-glycosylation in glypicans has never been investigated in detail. Here, we studied the role of the possible N-glycosylation sites at Asn-79 and Asn-116 in recombinant anchorless glypican-1 expressed in eukaryotic cells. Mutagenesis and enzymatic cleavage indicated that the potential N-glycosylation sites are invariably occupied. Experiments using the drug tunicamycin to inhibit the N-linked glycosylation of glypican-1 showed that secretion of anchorless glypican-1 was reduced and that the protein did not accumulate inside the cells. Heparan sulfate substitution of N-glycosylation mutant N116Q was similar to wild-type glypican-1 while the N79Q mutant and also the double mutant N79QN116Q were mostly secreted as high-molecular-weight heparan sulfate proteoglycan. N-Glycosylation mutants and N-deglycosylated glypican-1 had far-UV circular dichroism and fluorescence emission spectra that were highly similar to those of N-glycosylated glypican-1. A single unfolding transition at high concentrations of urea was found for both N-deglycosylated glypican-1 and glypican-1 in which the N-glycosylation sites had been removed by mutagenesis when chemical denaturation was monitored by circular dichroism and fluorescence emission spectroscopy. In summary, we have found that the potential N-glycosylation sites in glypican-1 are invariably occupied and that the N-linked glycans on glypican-1 affect protein expression and heparan sulfate substitution but that correct folding can be obtained in the absence of N-linked glycans.
|
|
| 8. |
- Velasco, Talia, et al.
(författare)
-
HIF-1α can act as a tumor suppressor gene in murine Acute Myeloid Leukemia.
- 2014
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 124:24, s. 3597-3607
-
Tidskriftsartikel (refereegranskat)abstract
- Self-renewal of hematopoietic stem cells (HSCs) and leukemia-initiating cells (LICs) has been proposed to be influenced by low oxygen tension (hypoxia). This signaling, related to the cellular localization inside the bone marrow niche and/or influenced by extrinsic factors, promotes the stabilization of hypoxia inducible factors (HIFs). Whether HIF-1α can be used as a therapeutic target in the treatment of myeloid malignancies remains unknown. We have used three different murine models to investigate the role of HIF-1α in acute myeloid leukemia (AML) initiation/progression and self-renewal of LICs. Unexpectedly, we failed to observe a delay or prevention of disease development from hematopoietic cells lacking Hif-1α. In contrast, deletion of Hif-1α resulted in faster development of the disease and an enhanced leukemia phenotype in some of the investigated models. Our results therefore warrant a reconsideration of the role of HIF-1α and, as a consequence, question its generic therapeutic usefulness in AML.
|
|
| 9. |
- Zhu, Iowis, et al.
(författare)
-
Modular design of synthetic receptors for programmed gene regulation in cell therapies
- 2022
-
Ingår i: Cell. - : Elsevier BV. - 0092-8674. ; 185:8, s. 16-1443
-
Tidskriftsartikel (refereegranskat)abstract
- Synthetic biology has established powerful tools to precisely control cell function. Engineering these systems to meet clinical requirements has enormous medical implications. Here, we adopted a clinically driven design process to build receptors for the autonomous control of therapeutic cells. We examined the function of key domains involved in regulated intramembrane proteolysis and showed that systematic modular engineering can generate a class of receptors that we call synthetic intramembrane proteolysis receptors (SNIPRs) that have tunable sensing and transcriptional response abilities. We demonstrate the therapeutic potential of the receptor platform by engineering human primary T cells for multi-antigen recognition and production of dosed, bioactive payloads relevant to the treatment of disease. Our design framework enables the development of fully humanized and customizable transcriptional receptors for the programming of therapeutic cells suitable for clinical translation.
|
|
| 10. |
|
|
