| 1. |
- Reuten, Raphael, et al.
(författare)
-
Basement membrane stiffness determines metastases formation
- 2021
-
Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122.
-
Tidskriftsartikel (refereegranskat)abstract
- The basement membrane (BM) is a special type of extracellular matrix and presents the major barrier cancer cells have to overcome multiple times to form metastases. Here we show that BM stiffness is a major determinant of metastases formation in several tissues and identify netrin-4 (Net4) as a key regulator of BM stiffness. Mechanistically, our biophysical and functional analyses in combination with mathematical simulations show that Net4 softens the mechanical properties of native BMs by opening laminin node complexes, decreasing cancer cell potential to transmigrate this barrier despite creating bigger pores. Our results therefore reveal that BM stiffness is dominant over pore size, and that the mechanical properties of ‘normal’ BMs determine metastases formation and patient survival independent of cancer-mediated alterations. Thus, identifying individual Net4 protein levels within native BMs in major metastatic organs may have the potential to define patient survival even before tumour formation. The ratio of Net4 to laminin molecules determines BM stiffness, such that the more Net4, the softer the BM, thereby decreasing cancer cell invasion activity.
|
|
| 2. |
|
|
| 3. |
- Bagger, Frederik Otzen, et al.
(författare)
-
HemaExplorer: a database of mRNA expression profiles in normal and malignant haematopoiesis.
- 2013
-
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 41:D1, s. 1034-1039
-
Tidskriftsartikel (refereegranskat)abstract
- The HemaExplorer (http://servers.binf.ku.dk/hemaexplorer) is a curated database of processed mRNA Gene expression profiles (GEPs) that provides an easy display of gene expression in haematopoietic cells. HemaExplorer contains GEPs derived from mouse/human haematopoietic stem and progenitor cells as well as from more differentiated cell types. Moreover, data from distinct subtypes of human acute myeloid leukemia is included in the database allowing researchers to directly compare gene expression of leukemic cells with those of their closest normal counterpart. Normalization and batch correction lead to full integrity of the data in the database. The HemaExplorer has comprehensive visualization interface that can make it useful as a daily tool for biologists and cancer researchers to assess the expression patterns of genes encountered in research or literature. HemaExplorer is relevant for all research within the fields of leukemia, immunology, cell differentiation and the biology of the haematopoietic system.
|
|
| 4. |
- Grigoryan, Ani, et al.
(författare)
-
Engineering human mini-bones for the standardized modeling of healthy hematopoiesis, leukemia, and solid tumor metastasis
- 2022
-
Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6242 .- 1946-6234. ; 14:666, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- The bone marrow microenvironment provides indispensable factors to sustain blood production throughout life. It is also a hotspot for the progression of hematologic disorders and the most frequent site of solid tumor metastasis. Preclinical research relies on xenograft mouse models, but these models preclude the human-specific functional interactions of stem cells with their bone marrow microenvironment. Instead, human mesenchymal cells can be exploited for the in vivo engineering of humanized niches, which confer robust engraftment of human healthy and malignant blood samples. However, mesenchymal cells are associated with major reproducibility issues in tissue formation. Here, we report the fast and standardized generation of human mini-bones by a custom-designed human mesenchymal cell line. These resulting humanized ossicles (hOss) consist of fully mature bone and bone marrow structures hosting a human mesenchymal niche with retained stem cell properties. As compared to mouse bones, we demonstrate superior engraftment of human cord blood hematopoietic cells and primary acute myeloid leukemia samples and also validate hOss as a metastatic site for breast cancer cells. We further report the engraftment of neuroblastoma patient-derived xenograft cells in a humanized model, recapitulating clinically described osteolytic lesions. Collectively, our human mini-bones constitute a powerful preclinical platform to model bone-developing tumors using patient-derived materials.
|
|
| 5. |
- Hasemann, Marie S., et al.
(författare)
-
Phosphorylation of Serine 248 of C/EBP alpha Is Dispensable for Myelopoiesis but Its Disruption Leads to a Low Penetrant Myeloid Disorder with Long Latency
- 2012
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:6
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Transcription factors play a key role in lineage commitment and differentiation of stem cells into distinct mature cells. In hematopoiesis, they regulate lineage-specific gene expression in a stage-specific manner through various physical and functional interactions with regulatory proteins that are simultanously recruited and activated to ensure timely gene expression. The transcription factor CCAAT/enhancer binding protein alpha (C/EBP alpha) is such a factor and is essential for the development of granulocytic/monocytic cells. The activity of C/EBP alpha is regulated on several levels including gene expression, alternative translation, protein interactions and posttranslational modifications, such as phosphorylation. In particular, the phosphorylation of serine 248 of the transactivation domain has been shown to be of crucial importance for granulocytic differentiation of 32Dcl3 cells in vitro. Methodology/Principal Findings: Here, we use mouse genetics to investigate the significance of C/EBP alpha serine 248 in vivo through the construction and analysis of Cebpa(S248A/S248A) knock-in mice. Surprisingly, 8-week old Cebpa(S248A/S248A) mice display normal steady-state hematopoiesis including unaltered development of mature myeloid cells. However, over time some of the animals develop a hematopoietic disorder with accumulation of multipotent, megakaryocytic and erythroid progenitor cells and a mild impairment of differentiation along the granulocytic-monocytic lineage. Furthermore, BM cells from Cebpa(S248A/S248A) animals display a competitive advantage compared to wild type cells in a transplantation assay. Conclusions/Significance: Taken together, our data shows that the substitution of C/EBP alpha serine 248 to alanine favors the selection of the megakaryocytic/erythroid lineage over the monocytic/granulocytic compartment in old mice and suggests that S248 phosphorylation may be required to maintain proper hematopoietic homeostasis in response to changes in the wiring of cellular signalling networks. More broadly, the marked differences between the phenotype of the S248A variant in vivo and in vitro highlight the need to exert caution when extending in vitro phenotypes to the more appropriate in vivo context.
|
|
| 6. |
- Kirstetter, Peggy, et al.
(författare)
-
Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block
- 2006
-
Ingår i: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 7:10, s. 1048-1056
-
Tidskriftsartikel (refereegranskat)abstract
- Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with loss of myeloid lineage commitment at the granulocyte-macrophage progenitor stage; blocked erythrocyte differentiation; disruption of lymphoid development; and loss of repopulating stem cell activity. Loss of hematopoietic stem cell function was associated with decreased expression of Cdkn1a ( encoding the cell cycle inhibitor p21(cdk)), Sfpi1, Hoxb4 and Bmi1 ( encoding the transcription factors PU.1, HoxB4 and Bmi-1, respectively) and altered integrin expression in Lin(-)Sca-1(+)c-Kit(+) cells, whereas PU.1 was upregulated in erythroid progenitors. Constitutive activation of canonical Wnt signaling therefore causes multilineage differentiation block and compromised hematopoietic stem cell maintenance.
|
|
| 7. |
- Kirstetter, Peggy, et al.
(författare)
-
Modeling of C/EBP alpha mutant acute myeloid leukemia reveals a common expression signature of committed myeloid leukemia-initiating cells
- 2008
-
Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 13:4, s. 299-310
-
Tidskriftsartikel (refereegranskat)abstract
- Mutations in the CEBPA gene are present in 7%-10% of human patients with acute myeloid leukemia (AML). However, no genetic models exist that demonstrate their etiological relevance. To mimic the most common mutations affecting CEBPA-that is, those leading to loss of the 42 kDa C/EBP alpha isoform (p42) while retaining the 30kDa isoform (p30)-we modified the mouse Cebpa locus to express only p30. p30 supported the formation of granulocyte-macrophage progenitors. However, p42 was required for control of myeloid progenitor proliferation, and p42-deficient mice developed AML with complete penetrance. p42-deficient leukemia could be transferred by a Mac1(+)c-Kit(+) population that gave rise only to myeloid cells in recipient mice. Expression profiling of this population against normal Mac1(+)c-Kit(+) progenitors revealed a signature shared with MLL-AF9-transformed AML.
|
|
| 8. |
- Rapin, Nicolas, et al.
(författare)
-
Comparing cancer vs normal gene expression profiles identifies new disease entities and common transcriptional programs in AML patients
- 2014
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 123:6, s. 894-904
-
Tidskriftsartikel (refereegranskat)abstract
- Gene expression profiling has been used extensively to characterize cancer, identify novel subtypes, and improve patient stratification. However, it has largely failed to identify transcriptional programs that differ between cancer and corresponding normal cells and has not been efficient in identifying expression changes fundamental to disease etiology. Here we present a method that facilitates the comparison of any cancer sample to its nearest normal cellular counterpart, using acute myeloid leukemia (AML) as a model. We first generated a gene expression-based landscape of the normal hematopoietic hierarchy, using expression profiles from normal stem/progenitor cells, and next mapped the AML patient samples to this landscape. This allowed us to identify the closest normal counterpart of individual AML samples and determine gene expression changes between cancer and normal. We find the cancer vs normal method (CvN method) to be superior to conventional methods in stratifying AML patients with aberrant karyotype and in identifying common aberrant transcriptional programs with potential importance for AML etiology. Moreover, the CvN method uncovered a novel poor-outcome subtype of normal-karyotype AML, which allowed for the generation of a highly prognostic survival signature. Collectively, our CvN method holds great potential as a tool for the analysis of gene expression profiles of cancer patients.
|
|
| 9. |
- Thoren, Lina A., et al.
(författare)
-
UPF2 Is a Critical Regulator of Liver Development, Function and Regeneration
- 2010
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:7
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Nonsense-mediated mRNA decay (NMD) is a post-transcriptional RNA surveillance process that facilitates the recognition and destruction of mRNAs bearing premature terminations codons (PTCs). Such PTC-containing (PTC+) mRNAs may arise from different processes, including erroneous processing and expression of pseudogenes, but also from more regulated events such as alternative splicing coupled NMD (AS-NMD). Thus, the NMD pathway serves both as a silencer of genomic noise and a regulator of gene expression. Given the early embryonic lethality in NMD deficient mice, uncovering the full regulatory potential of the NMD pathway in mammals will require the functional assessment of NMD in different tissues. Methodology/Principal Findings: Here we use mouse genetics to address the role of UPF2, a core NMD component, in the development, function and regeneration of the liver. We find that loss of NMD during fetal liver development is incompatible with postnatal life due to failure of terminal differentiation. Moreover, deletion of Upf2 in the adult liver results in hepatosteatosis and disruption of liver homeostasis. Finally, NMD was found to be absolutely required for liver regeneration. Conclusion/Significance: Collectively, our data demonstrate the critical role of the NMD pathway in liver development, function and regeneration and highlights the importance of NMD for mammalian biology.
|
|
