| 1. |
- Nelson, Michelle H., et al.
(author)
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The Bispecific Tumor Antigen-Conditional 4-1BB x 5T4 Agonist, ALG.APV-527, Mediates Strong T-Cell Activation and Potent Antitumor Activity in Preclinical Studies
- 2023
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In: Molecular Cancer Therapeutics. - 1538-8514. ; 22:1, s. 89-101
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Journal article (peer-reviewed)abstract
- 4-1BB (CD137) is an activation-induced costimulatory receptor that regulates immune responses of activated CD8 T and natural killer cells, by enhancing proliferation, survival, cytolytic activity, and IFNγ production. The ability to induce potent antitumor activity by stimulating 4-1BB on tumor-specific cytotoxic T cells makes 4-1BB an attractive target for designing novel immuno-oncology therapeutics. To minimize systemic immune toxicities and enhance activity at the tumor site, we have developed a novel bispecific antibody that stimulates 4-1BB function when co-engaged with the tumor-associated antigen 5T4. ALG.APV-527 was built on the basis of the ADAPTIR bispecific platform with optimized binding domains to 4-1BB and 5T4 originating from the ALLIGATOR-GOLD human single-chain variable fragment library. The epitope of ALG.APV-527 was determined to be located at domain 1 and 2 on 4-1BB using X-ray crystallography. As shown in reporter and primary cell assays in vitro, ALG.APV-527 triggers dose-dependent 4-1BB activity mediated only by 5T4 crosslinking. In vivo, ALG.APV-527 demonstrates robust antitumor responses, by inhibiting growth of established tumors expressing human 5T4 followed by a long-lasting memory immune response. ALG.APV-527 has an antibody-like half-life in cynomolgus macaques and was well tolerated at 50.5 mg/kg. ALG.APV-527 is uniquely designed for 5T4-conditional 4-1BB-mediated antitumor activity with potential to minimize systemic immune activation and hepatotoxicity while providing efficacious tumor-specific responses in a range of 5T4-expressing tumor indications as shown by robust activity in preclinical in vitro and in vivo models. On the basis of the combined preclinical dataset, ALG.APV-527 has potential as a promising anticancer therapeutic for the treatment of 5T4-expressing tumors.
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| 2. |
- Askmyr, Maria, et al.
(author)
-
Ciliary neurotrophic factor has intrinsic and extrinsic roles in regulating B cell differentiation and bone structure.
- 2015
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Journal article (peer-reviewed)abstract
- The gp130 receptor and its binding partners play a central role in cytokine signalling. Ciliary neurotrophic factor (CNTF) is one of the cytokines that signals through the gp130 receptor complex. CNTF has previously been shown to be a negative regulator of trabecular bone remodelling and important for motor neuron development. Since haematopoietic cell maintenance and differentiation is dependent on the bone marrow (BM) microenvironment, where cells of the osteoblastic lineage are important regulators, we hypothesised that CNTF may also have important roles in regulating haematopoiesis. Analysis of haematopoietic parameters in male and female Cntf(-/-) mice at 12 and 24 weeks of age revealed altered B lymphopoiesis. Strikingly, the B lymphocyte phenotype differed based on sex, age and also the BM microenvironment in which the B cells develop. When BM cells from wildtype mice were transplanted into Cntf(-/-) mice, there were minimal effects on B lymphopoiesis or bone parameters. However, when Cntf(-/-) BM cells were transplanted into a wildtype BM microenvironment, there were changes in both haematopoiesis and bone parameters. Our data reveal that haematopoietic cell-derived CNTF has roles in regulating BM B cell lymphopoiesis and both trabecular and cortical bone, the latter in a sex-dependent manner.
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| 3. |
- Askmyr, Maria K, et al.
(author)
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Towards a better understanding and new therapeutics of osteopetrosis.
- 2008
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In: British journal of haematology. - : Wiley. - 1365-2141 .- 0007-1048. ; 140:6, s. 597-609
-
Research review (peer-reviewed)abstract
- Lack of or dysfunction in osteoclasts result in osteopetrosis, a group of rare but often severe, genetic disorders affecting skeletal tissue. Increase in bone mass results in skeletal malformation and bone marrow failure that may be fatal. Many of the underlying defects have lately been characterized in humans and in animal models of the disease. In humans, these defects often involve mutations in genes expressing proteins involved in the acidification of the osteoclast resorption compartment, a process necessary for proper bone degradation. So far, the only cure for children with severe osteopetrosis is allogeneic hematopoietic stem cell (HSC) transplantation but without a matching donor this form of therapy is far from optimal. The characterization of the genetic defects opens up the possibility for gene replacement therapy as an alternative. Accordingly, HSC-targeted gene therapy in a mouse model of infantile malignant osteopetrosis was recently shown to correct many aspects of the disease.
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| 4. |
- Askmyr, Maria, et al.
(author)
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Low-dose busulphan conditioning and neonatal stem cell transplantation preserves vision and restores hematopoiesis in severe murine osteopetrosis.
- 2009
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In: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 37, s. 302-308
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Infantile malignant osteopetrosis is a fatal disease caused by lack of functional osteoclasts. In most of patients, TCIRG1, encoding a subunit of a proton pump essential for bone resorption, is mutated. Osteopetrosis leads to bone marrow failure and blindness due to optic nerve compression. Oc/oc mice have a deletion in Tcirg1 and die around 3 to 4 weeks, but can be rescued by neonatal stem cell transplantation (SCT) after irradiation conditioning. However, as irradiation of neonatal mice results in retinal degeneration, we wanted to investigate whether conditioning with busulphan prior to SCT can lead to preservation of vision and reversal of osteopetrosis in the oc/oc mouse model. MATERIALS AND METHODS: Pregnant dams were conditioned with busulphan and their litters transplanted with 1 x 10(6) normal lineage-depleted bone marrow cells intravenously or intraperitoneally. Mice were followed in terms of survival and engraftment level, as well as with peripheral blood lineage analysis, bone and eye histopathology and a visual-tracking drum test to assess vision. RESULTS: Busulphan at 15 mg/kg was toxic to oc/oc mice. However, six of seven oc/oc mice conditioned with busulphan 7.5 mg/kg survived past the normal lifespan with 10% engraftment, correction of the skeletal phenotype, and normalization of peripheral blood lineages. Busulphan, in contrast to irradiation, did not have adverse effects on the retina as determined by histopathology, and 8 weeks after transplantation control and oc/oc mice retained their vision. CONCLUSION: Low-dose busulphan conditioning and neonatal SCT leads to prolonged survival of oc/oc mice, reverses osteopetrosis and prevents blindness even at low engraftment levels.
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| 5. |
- Askmyr, Maria, et al.
(author)
-
Modeling chronic myeloid leukemia in immunodeficient mice reveals expansion of aberrant mast cells and accumulation of pre-B cells.
- 2014
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In: Blood Cancer Journal. - : Springer Science and Business Media LLC. - 2044-5385. ; 4
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Journal article (peer-reviewed)abstract
- Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that, if not treated, will progress into blast crisis (BC) of either myeloid or B lymphoid phenotype. The BCR-ABL1 fusion gene, encoding a constitutively active tyrosine kinase, is thought to be sufficient to cause chronic phase (CP) CML, whereas additional genetic lesions are needed for progression into CML BC. To generate a humanized CML model, we retrovirally expressed BCR-ABL1 in the cord blood CD34(+) cells and transplanted these into NOD-SCID (non-obese diabetic/severe-combined immunodeficient) interleukin-2-receptor γ-deficient mice. In primary mice, BCR-ABL1 expression induced an inflammatory-like state in the bone marrow and spleen, and mast cells were the only myeloid lineage specifically expanded by BCR-ABL1. Upon secondary transplantation, the pronounced inflammatory phenotype was lost and mainly human mast cells and macrophages were found in the bone marrow. Moreover, a striking block at the pre-B-cell stage was observed in primary mice, resulting in an accumulation of pre-B cells. A similar block in B-cell differentiation could be confirmed in primary cells from CML patients. Hence, this humanized mouse model of CML reveals previously unexplored features of CP CML and should be useful for further studies to understand the disease pathogenesis of CML.
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| 6. |
- Askmyr, Maria, et al.
(author)
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Prospects for gene therapy of osteopetrosis.
- 2009
-
In: Current gene therapy. - 1566-5232. ; 9:3, s. 150-9
-
Research review (peer-reviewed)abstract
- Dysfunction in or lack of osteoclasts result in osteopetrosis, a group of rare but often severe, genetic disorders characterized by an increase in bone mass, skeletal malformations and bone marrow failure that may be fatal. Several of the underlying defects have lately been characterized in humans and in animal disease models. In humans, these defects often involve mutations in genes expressing proteins involved in the acidification of the osteoclast sub-cellular compartment, a process necessary for proper bone resorption. So far, the only cure for children with severe osteopetrosis is allogeneic hematopoietic stem cell transplantation (SCT). However, the characterization of the genetic defects opens up the possibility for gene replacement therapy as an alternative to SCT. Recently, gene therapy targeting hematopoietic stem cells (HSC) in a mouse model of infantile malignant osteopetrosis was shown to correct many aspects of the disease. Here we review important aspects of this group of diseases and discuss the prospects for development of gene therapy of osteopetrosis.
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| 7. |
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| 8. |
- Askmyr, Maria
(author)
-
Towards Gene Therapy of Osteopetrosis.
- 2007
-
Doctoral thesis (other academic/artistic)abstract
- The goal in this thesis is development of gene therapy for malignant infantile osteopetrosis (IMO), a rare but severe genetic bone disease. The concept of osteopetrosis implies dysfunction or lack of osteoclasts, the bone resorbing cells in our body, resulting in failure of normal bone breakdown. Although involved in bone remodeling, osteoclasts are of hematopoietic origin and may potentially be targeted by genetic modification of hematopoietic stem cells (HSCs). Recently, clinical progress within the field of gene therapy has been achieved for other monogenic diseases affecting the hematopoietic system thereby providing hope for future clinical application also for osteopetrosis. We have been working with a mouse model of IMO called the oc/oc mouse and have been able to correct the otherwise lethal osteopetrotic phenotype in theses animals by transplantation of normal bone marrow. In addition, we established optimal pre-transplantation irradiation dose, cell dose and onset of treatment. Further studies in the oc/oc mouse model involved gene therapy where oc/oc fetal liver derived HSCs were transduced with a retroviral vector and subsequently transplanted into oc/oc mice. In vitro studies of osteoclast function revealed a partial restoration of bone resorbing activity. The osteopetrotic phenotype was reversed and this resulted in long-term survival of transplanted mice. The present findings provide a first and significant step towards the development of gene therapy in patients with malignant osteopetrosis. To prepare for human gene therapy, we also investigated the ability of lentiviral vectors, produced by stable packaging cell lines, to transduce human CD34+ SCID repopulating cells.
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| 9. |
- Askmyr, Maria, et al.
(author)
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Transgenic expression of human cytokines in immunodeficient mice does not facilitate myeloid expansion of BCR-ABL1 transduced human cord blood cells
- 2017
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:10
-
Journal article (peer-reviewed)abstract
- Several attempts have been made to model chronic myeloid leukemia (CML) in a xenograft setting but expansion of human myeloid cells in immunodeficient mice has proven difficult to achieve. Lack of cross-reacting cytokines in the microenvironment of the mice has been proposed as a potential reason. In this study we have used NOD/SCID IL2–receptor gamma deficient mice expressing human SCF, IL-3 and GM-CSF (NSGS mice), that should be superior in supporting human, and particularly, myeloid cell engraftment, to expand BCR-ABL1 expressing human cells in order to model CML. NSGS mice transplanted with BCR-ABL1 expressing cells became anemic and had to be sacrificed due to illness, however, this was not accompanied by an expansion of human myeloid cells but rather we observed a massive expansion of human T-cells and macrophages/histiocytes. Importantly, control human cells without BCR-ABL1 expression elicited a similar reaction, although with a slight delay of disease induction, suggesting that while BCR-ABL1 contributes to the inflammatory reaction, the presence of normal human hematopoietic cells is detrimental for NSGS mice.
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| 10. |
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| 11. |
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| 12. |
- Flores Bjurström, Carmen, et al.
(author)
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Nonablative neonatal bone marrow transplantation rapidly reverses severe murine osteopetrosis despite low level engraftment and lack of selective expansion of the osteoclastic lineage.
- 2010
-
In: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 25:9, s. 2069-2077
-
Journal article (peer-reviewed)abstract
- Infantile malignant osteopetrosis (IMO) is caused by lack of functional osteoclasts leading to skeletal abnormalities, blindness due to compression of the optic nerves, bone marrow (BM) failure and early death. In most patients TCIRG1, a proton pump subunit essential for bone resorption, is mutated. Oc/oc mice represent a model for IMO due to a deletion in Tcirg1 and die around 4 weeks. To determine if hematopoietic stem cell transplantation without prior conditioning can reverse osteopetrosis, neonatal mice were transplanted iv with lineage depleted BM cells. More than 85% of oc/oc mice transplanted with 5 x 10(6) cells survived long term with an engraftment of 3-5% in peripheral blood (PB). At 3 w engraftment in the BM was 1-2% but the cellularity had increased 60-fold compared to non-treated oc/oc and RANKL and M-CSF expression in the BM was normalized. Histopathology and micro-CT revealed almost complete reversal of osteopetrosis after 4 weeks. In vitro studies showed that bone resorption by osteoclasts from transplanted oc/oc mice was 14% of transplanted controls and immunofluorescence microscopy revealed that resorption was mainly associated with osteoclasts of donor origin. Lineage analysis of BM, PB and spleen did not provide any evidence for selective recruitment of cells to the osteoclastic lineage. The vision was also preserved in transplanted oc/oc mice as determined by a visual tracking drum test. In summary, nonablative neonatal transplantation leading to engraftment of only a small fraction of normal cells rapidly reverses severe osteopetrosis in the oc/oc mouse model. (c) 2010 American Society for Bone and Mineral Research.
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| 13. |
- Hansen, Nils, et al.
(author)
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SOCS2 is dispensable for BCR/ABL1-induced chronic myeloid leukemia-like disease and for normal hematopoietic stem cell function.
- 2013
-
In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 27, s. 130-135
-
Journal article (peer-reviewed)abstract
- Suppressor of cytokine signaling 2 (SOCS2) is known as a feedback inhibitor of cytokine signaling and is highly expressed in primary bone marrow (BM) cells from patients with chronic myeloid leukemia (CML). However, it has not been established whether SOCS2 is involved in CML, caused by the BCR/ABL1 fusion gene, or important for normal hematopoietic stem cell (HSC) function. In this study, we demonstrate that although Socs2 was found to be preferentially expressed in long-term HSCs, Socs2-deficient HSCs were indistinguishable from wild-type HSCs when challenged in competitive BM transplantation experiments. Furthermore, by using a retroviral BCR/ABL1-induced mouse model of CML, we demonstrate that SOCS2 is dispensable for the induction and propagation of the disease, suggesting that the SOCS2-mediated feedback regulation of the JAK/STAT pathway is deficient in BCR/ABL1-induced CML.Leukemia advance online publication, 24 July 2012; doi:10.1038/leu.2012.169.
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| 14. |
- Henriksen, Kim, et al.
(author)
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Dissociation of Bone Resorption and Bone Formation in Adult Mice with a Non-Functional V-ATPase in Osteoclasts Leads to Increased Bone Strength
- 2011
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:11
-
Journal article (peer-reviewed)abstract
- Osteopetrosis caused by defective acid secretion by the osteoclast, is characterized by defective bone resorption, increased osteoclast numbers, while bone formation is normal or increased. In contrast the bones are of poor quality, despite this uncoupling of formation from resorption. To shed light on the effect of uncoupling in adult mice with respect to bone strength, we transplanted irradiated three-month old normal mice with hematopoietic stem cells from control or oc/oc mice, which have defective acid secretion, and followed them for 12 to 28 weeks. Engraftment levels were assessed by flow cytometry of peripheral blood. Serum samples were collected every six weeks for measurement of bone turnover markers. At termination bones were collected for mu CT and mechanical testing. An engraftment level of 98% was obtained. From week 6 until termination bone resorption was significantly reduced, while the osteoclast number was increased when comparing oc/oc to controls. Bone formation was elevated at week 6, normalized at week 12, and reduced onwards. mu CT and mechanical analyses of femurs and vertebrae showed increased bone volume and bone strength of cortical and trabecular bone. In conclusion, these data show that attenuation of acid secretion in adult mice leads to uncoupling and improves bone strength.
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| 15. |
- Johansson, M. K., et al.
(author)
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Hematopoietic stem cell-targeted neonatal gene therapy reverses lethally progressive osteopetrosis in oc/oc mice
- 2007
-
In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 109:12, s. 5178-85
-
Journal article (peer-reviewed)abstract
- Infantile malignant osteopetrosis (IMO) is a fatal disease caused by lack of functional osteoclasts, and the only available treatment is hematopoietic stem cell (HSC) transplantation. In the majority of patients, the TCIRG1 gene, coding for a subunit of a proton pump essential for bone resorption, is mutated. Oc/oc mice have a deletion in the homologue gene (tcirg1) and die at 3 to 4 weeks, but can be rescued by neonatal transplantation of HSCs. Here, HSC-targeted gene therapy of osteopetrosis in the oc/oc mouse model was developed. Oc/oc fetal liver cells depleted of Ter119-expressing erythroid cells were transduced with a retroviral vector expressing tcirg1 and GFP, and subsequently transplanted intraperitoneally to irradiated neonatal oc/oc mice. Eight of 15 mice survived past the normal life span of oc/oc mice. In vitro osteoclastogenesis revealed formation of GFP-positive osteoclasts and bone resorption, albeit at a lower level than from wild-type cells. The skeletal phenotype was analyzed by X-ray and histopathology and showed partial correction at 8 weeks and almost normalization after 18 weeks. In summary, osteopetrosis in oc/oc mice can be reversed by neonatal transplantation of gene-modified HSCs leading to long-term survival. This represents a significant step toward the development of gene therapy for osteopetrosis.
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| 16. |
- Johansson, M., et al.
(author)
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Neonatal hematopoietic stem cell transplantation cures oc/oc mice from osteopetrosis
- 2006
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In: Exp Hematol. - : Elsevier BV. - 0301-472X .- 1873-2399. ; 34:2, s. 242-9
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Infantile malignant osteopetrosis (IMO) is a rare autosomal recessive disorder affecting osteoclast function. Fifty percent of the patients have a mutation in the TCIRG1 gene coding for one subunit of an osteoclast proton pump. The only curative treatment is hematopoietic stem cell transplantation (SCT). The oc/oc mouse has a mutation in the gene homologous to TCIRG1 and its expected lifespan is only 3 to 4 weeks. Previous attempts to cure these mice with SCT have been unsuccessful. We wanted to determine if early hematopoietic SCT using enriched and MHC-matched stem cells can cure oc/oc mice from osteopetrosis. METHODS: One- and 8-day-old oc/oc and control mice were radiated with 200, 400, or 600 cGy and transplanted intraperitoneally with 1 or 5 x 10(6) normal lineage-depleted bone marrow cells. Blood, x-ray, and pathology analyses were performed on transplanted mice. RESULTS: All 1-day-old mice irradiated with 400 cGy and transplanted with 5 x 10(6) cells survived long term. An engraftment level of 20% is sufficient to correct most features of the disease. X-ray and histopathology examination of transplanted animals showed normalization of bone structure. However, although a correction of bone structure occurred, the transplanted oc/oc mice were smaller in size than their littermates. In contrast to untreated animals, oc/oc mice developed teeth after transplantation, but with abnormal structure and shape making them unusable. CONCLUSION: We have shown that this murine form of IMO is curable with neonatal SCT using enriched stem cells.
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| 17. |
- Landberg, Niklas, et al.
(author)
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CD36 defines primitive chronic myeloid leukemia cells less responsive to imatinib but vulnerable to antibody-based therapeutic targeting
- 2018
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In: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 103:3, s. 447-455
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Journal article (peer-reviewed)abstract
- Tyrosine kinase inhibitors (TKIs) are highly effective for the treatment of chronic myeloid leukemia (CML), but very few patients are cured. The major drawbacks regarding TKIs are their low efficacy in eradicating the leukemic stem cells responsible for disease maintenance and relapse upon drug cessation. Herein, we performed ribonucleic acid sequencing of flow-sorted primitive (CD34+CD38low) and progenitor (CD34+CD38+) chronic phase CML cells, and identified transcriptional upregulation of 32 cell surface molecules relative to corresponding normal bone marrow cells. Focusing on novel markers with increased expression on primitive CML cells, we confirmed upregulation of the scavenger receptor CD36 and the leptin receptor by flow cytometry. We also delineate a subpopulation of primitive CML cells expressing CD36 that is less sensitive to imatinib treatment. Using CD36 targeting antibodies, we show that the CD36 positive cells can be targeted and killed by antibody-dependent cellular cytotoxicity. In summary, CD36 defines a subpopulation of primitive CML cells with decreased imatinib sensitivity that can be effectively targeted and killed using an anti-CD36 antibody.
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| 18. |
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| 19. |
- Lilljebjörn, Henrik, et al.
(author)
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Identification of ETV6-RUNX1-like and DUX4-rearranged subtypes in paediatric B-cell precursor acute lymphoblastic leukaemia
- 2016
-
In: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11790
-
Journal article (peer-reviewed)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.
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| 20. |
- Moscatelli, Ilana, et al.
(author)
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Gene therapy for infantile malignant osteopetrosis : review of pre-clinical research and proof-of-concept for phenotypic reversal
- 2021
-
In: Molecular Therapy - Methods and Clinical Development. - : Elsevier BV. - 2329-0501. ; 20, s. 389-397
-
Research review (peer-reviewed)abstract
- Infantile malignant osteopetrosis is a devastating disorder of early childhood that is frequently fatal and for which there are only limited therapeutic options. Gene therapy utilizing autologous hematopoietic stem and progenitor cells represents a potentially advantageous therapeutic alternative for this multisystemic disease. Gene therapy can be performed relatively rapidly following diagnosis, will not result in graft versus host disease, and may also have potential for reduced incidences of other transplant-related complications. In this review, we have summarized the past sixteen years of research aimed at developing a gene therapy for infantile malignant osteopetrosis; these efforts have culminated in the first clinical trial employing lentiviral-mediated delivery of TCIRG1 in autologous hematopoietic stem and progenitor cells. Infantile malignant osteopetrosis (IMO) presents a highly unmet medical need with limited therapeutic options. Gene therapy utilizing autologous hematopoietic stem and progenitor cells represents a potentially advantageous therapeutic alternative for this disease. Here, we have summarized all nonclinical studies supporting the initiation of a clinical gene therapy trial for IMO.
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| 21. |
- Moscatelli, Ilana, et al.
(author)
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Lentiviral gene transfer of TCIRG1 into peripheral blood CD34(+) cells restores osteoclast function in infantile malignant osteopetrosis.
- 2013
-
In: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 57:1, s. 1-9
-
Journal article (peer-reviewed)abstract
- Infantile malignant osteopetrosis (IMO) is a rare, lethal, autosomal recessive disorder characterized by non-functional osteoclasts. More than 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. The aim of this study was to restore the resorptive function of IMO osteoclasts by lentiviral mediated gene transfer of the TCIRG1 cDNA. CD34(+) cells from peripheral blood of five IMO patients and from normal cord blood were transduced with lentiviral vectors expressing TCIRG1 and GFP under a SFFV promoter, expanded in culture and differentiated on bone slices to mature osteoclasts. qPCR analysis and western blot revealed increased mRNA and protein levels of TCIRG1, comparable to controls. Vector corrected IMO osteoclasts generated increased release of Ca(2+) and bone degradation product CTX-I into the media as well as increased formation of resorption pits in the bone slices, while non-corrected IMO osteoclasts failed to resorb bone. Resorption was approximately 70-80% of that of osteoclasts generated from cord blood. Furthermore, transduced CD34(+) cells successfully engrafted in NSG-mice. In conclusion we provide the first evidence of lentiviral-mediated correction of a human genetic disease affecting the osteoclastic lineage.
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| 22. |
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| 23. |
- von Palffy, Sofia, et al.
(author)
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A high-content cytokine screen identifies myostatin propeptide as a positive regulator of primitive chronic myeloid leukemia cells
- 2020
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In: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 105:8, s. 2095-2104
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Journal article (peer-reviewed)abstract
- Aberrantly expressed cytokines in the bone marrow (BM) niche are increasingly recognized as critical mediators of survival and expansion of leukemic stem cells. To identify regulators of primitive chronic myeloid leukemia (CML) cells, we performed a high-content cytokine screen using primary CD34+ CD38low chronic phase CML cells. Out of the 313 unique human cytokines evaluated, 11 were found to expand cell numbers ≥2-fold in a 7-day culture. Focusing on novel positive regulators of primitive CML cells, the myostatin antagonist myostatin propeptide gave the largest increase in cell expansion and was chosen for further studies. Herein, we demonstrate that myostatin propeptide expands primitive CML and normal BM cells, as shown by increased colony-forming capacity. For primary CML samples, retention of CD34-expression was also seen after culture. Furthermore, we show expression of MSTN by CML mesenchymal stromal cells, and that myostatin propeptide has a direct and instant effect on CML cells, independent of myostatin, by demonstrating binding of myostatin propeptide to the cell surface and increased phosphorylation of STAT5 and SMAD2/3. In summary, we identify myostatin propeptide as a novel positive regulator of primitive CML cells and corresponding normal hematopoietic cells.
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| 24. |
- Ågerstam, Helena, et al.
(author)
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Antibodies targeting human IL1RAP (IL1R3) show therapeutic effects in xenograft models of acute myeloid leukemia.
- 2015
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In: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 112:34, s. 10786-10791
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Journal article (peer-reviewed)abstract
- Acute myeloid leukemia (AML) is associated with a poor survival rate, and there is an urgent need for novel and more efficient therapies, ideally targeting AML stem cells that are essential for maintaining the disease. The interleukin 1 receptor accessory protein (IL1RAP; IL1R3) is expressed on candidate leukemic stem cells in the majority of AML patients, but not on normal hematopoietic stem cells. We show here that monoclonal antibodies targeting IL1RAP have strong antileukemic effects in xenograft models of human AML. We demonstrate that effector-cell-mediated killing is essential for the observed therapeutic effects and that natural killer cells constitute a critical human effector cell type. Because IL-1 signaling is important for the growth of AML cells, we generated an IL1RAP-targeting antibody capable of blocking IL-1 signaling and show that this antibody suppresses the proliferation of primary human AML cells. Hence, IL1RAP can be efficiently targeted with an anti-IL1RAP antibody capable of both achieving antibody-dependent cellular cytotoxicity and blocking of IL-1 signaling as modes of action. Collectively, these results provide important evidence in support of IL1RAP as a target for antibody-based treatment of AML.
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| 25. |
- Ågerstam, Helena, et al.
(author)
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IL1RAP antibodies block IL-1-induced expansion of candidate CML stem cells and mediate cell killing in xenograft models.
- 2016
-
In: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 128:23, s. 2683-2693
-
Journal article (peer-reviewed)abstract
- Chronic myeloid leukemia (CML) is currently treated with tyrosine kinase inhibitors, but these do not effectively eliminate the CML stem cells. As a consequence, CML stem cells persist and cause relapse in most patients upon drug discontinuation. Furthermore, no effective therapy exists for the advanced stages of the disease. Interleukin-1 receptor accessory protein (IL1RAP; IL1R3) is a coreceptor of interleukin-1 receptor type 1 and has been found upregulated on CML stem cells. Here, we show that primitive (CD34(+)CD38(-)) CML cells, in contrast to corresponding normal cells, express a functional interleukin-1 (IL-1) receptor complex and respond with NF-κB activation and marked proliferation in response to IL-1. IL1RAP antibodies that inhibit IL-1 signaling could block these effects. In vivo administration of IL1RAP antibodies in mice transplanted with chronic and blast phase CML cells resulted in therapeutic effects mediated by murine effector cells. These results provide novel insights into the role of IL1RAP in CML and a strong rationale for the development of an IL1RAP antibody therapy to target residual CML stem cells.
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