| 1. |
- Agarwal, Shruti, et al.
(författare)
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The activation loop tyrosine 823 is essential for the transforming capacity of the c-Kit oncogenic mutant D816V.
- 2015
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 34:35, s. 4581-4590
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Tidskriftsartikel (refereegranskat)abstract
- Oncogenic c-Kit mutations have been shown to display ligand-independent receptor activation and cell proliferation. A substitution of aspartate to valine at amino acid 816 (D816V) is one of the most commonly found oncogenic c-Kit mutations and is found in >90% of cases of mastocytosis and less commonly in germ-cell tumors, core-binding factor acute myeloid leukemia and mucosal melanomas. The mechanisms by which this mutation leads to constitutive activation and transformation are not fully understood. Previous studies have shown that the D816V mutation causes a structural change in the activation loop (A-loop), resulting in weaker binding of the A-loop to the juxtamembrane domain. In this paper, we have investigated the role of Y823, the only tyrosine residue in the A-loop, and its role in oncogenic transformation by c-Kit/D816V by introducing the Y823F mutation. Although dispensable for the kinase activity of c-Kit/D816V, the presence of Y823 was crucial for cell proliferation and survival. Furthermore, mutation of Y823 selectively downregulates the Ras/Erk and Akt pathways as well as the phosphorylation of STAT5 and reduces the transforming capacity of the D816V/c-Kit in vitro. We further show that mice injected with cells expressing c-Kit/D816V/Y823F display significantly reduced tumor size as well as tumor weight compared with controls. Finally, microarray analysis, comparing Y823F/D816V cells with cells expressing c-Kit/D816V, demonstrate that mutation of Y823 causes upregulation of proapoptotic genes, whereas genes of survival pathways are downregulated. Thus, phosphorylation of Y823 is not necessary for kinase activation, but essential for the transforming ability of the c-Kit/D816V mutant.Oncogene advance online publication, 1 December 2014; doi:10.1038/onc.2014.383.
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| 2. |
- Allaoui, Roni, et al.
(författare)
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Cancer-associated fibroblast-secreted CXCL16 attracts monocytes to promote stroma activation in triple-negative breast cancers
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Triple-negative (TN) breast cancers (ER â ' PR â ' HER2 â ') are highly metastatic and associated with poor prognosis. Within this subtype, invasive, stroma-rich tumours with infiltration of inflammatory cells are even more aggressive. The effect of myeloid cells on reactive stroma formation in TN breast cancer is largely unknown. Here, we show that primary human monocytes have a survival advantage, proliferate in vivo and develop into immunosuppressive myeloid cells expressing the myeloid-derived suppressor cell marker S100A9 only in a TN breast cancer environment. This results in activation of cancer-associated fibroblasts and expression of CXCL16, which we show to be a monocyte chemoattractant. We propose that this migratory feedback loop amplifies the formation of a reactive stroma, contributing to the aggressive phenotype of TN breast tumours. These insights could help select more suitable therapies targeting the stromal component of these tumours, and could aid prediction of drug resistance.
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| 3. |
- Arbajian, Elsa, et al.
(författare)
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Methylation patterns and chromatin accessibility in neuroendocrine lung cancer
- 2020
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 12:8, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Lung cancer is the worldwide leading cause of death from cancer. Epigenetic modifications such as methylation and changes in chromatin accessibility are major gene regulatory mechanisms involved in tumorigenesis and cellular lineage commitment. We aimed to characterize these processes in the context of neuroendocrine (NE) lung cancer. Illumina 450K DNA methylation data were collected for 1407 lung cancers including 27 NE tumors. NE differentially methylated regions (NE-DMRs) were identified and correlated with gene expression data for 151 lung cancers and 31 human tissue entities from the Genotype-Tissue Expression (GTEx) consortium. Assay for transposase-accessible chromatin sequencing (ATAC-seq) and RNA sequencing (RNA-seq) were performed on eight lung cancer cell lines, including three NE cell lines, to identify neuroendocrine specific gene regulatory elements. We identified DMRs with methylation patterns associated with differential gene expression and an NE tumor phenotype. DMR-associated genes could further be split into six functional modules, including one highly specific gene module for NE lung cancer showing high expression in both normal and malignant brain tissue. The regulatory potential of NE-DMRs was further validated in vitro using paired ATAC-and RNA-seq and revealed both proximal and distal regulatory elements of canonical NE-marker genes such as CHGA, NCAM1, INSM1, as well as a number of novel candidate markers of NE lung cancer. Using multilevel genomic analyses of both tumor bulk tissue and lung cancer cell lines, we identified a large catalogue of gene regulatory elements related to the NE phenotype of lung cancer.
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| 4. |
- Braekeveldt, Noémie, et al.
(författare)
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Neuroblastoma Patient-Derived Orthotopic Xenografts Retain Metastatic Patterns and Geno- and Phenotypes of Patient Tumours.
- 2015
-
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 136:5, s. 252-261
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a childhood tumour with heterogeneous characteristics and children with metastatic disease often have a poor outcome. Here we describe the establishment of neuroblastoma patient-derived xenografts (PDXs) by orthotopic implantation of viably cryopreserved or fresh tumour explants of patients with high risk neuroblastoma into immunodeficient mice. In vivo tumour growth was monitored by magnetic resonance imaging and fluorodeoxyglucose - positron emission tomography. Neuroblastoma PDXs retained the undifferentiated histology and proliferative capacity of their corresponding patient tumours. The PDXs expressed neuroblastoma markers NCAM, chromogranin A, synaptophysin and tyrosine hydroxylase. Whole genome genotyping array analyses demonstrated that PDXs retained patient-specific chromosomal aberrations such as MYCN amplification, deletion of 1p, and gain of chromosome 17q. Thus, neuroblastoma PDXs recapitulate the hallmarks of high-risk neuroblastoma in patients. PDX-derived cells were cultured in serum-free medium where they formed free-floating neurospheres, expressed neuroblastoma gene markers MYCN, CHGA, TH, SYP and NPY, and retained tumour-initiating and metastatic capacity in vivo. PDXs showed much higher degree of infiltrative growth and distant metastasis as compared to neuroblastoma SK-N-BE(2)c cell line-derived orthotopic tumours. Importantly, the PDXs presented with bone marrow involvement, a clinical feature of aggressive neuroblastoma. Thus, neuroblastoma PDXs serve as clinically relevant models for studying and targeting high-risk metastatic neuroblastoma. © 2014 Wiley Periodicals, Inc.
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| 5. |
- Carroll, Christopher, et al.
(författare)
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Hypoxia Generated by Avian Embryo Growth Induces the HIF-α Response and Critical Vascularization
- 2021
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 9, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Cancer research has transformed our view on cellular mechanisms for oxygen sensing. It has been documented that these mechanisms are important for maintaining animal tissues and life in environments where oxygen (O2) concentrations fluctuate. In adult animals, oxygen sensing is governed by the Hypoxia Inducible Factors (HIFs) that are stabilized at low oxygen concentrations (hypoxia). However, the importance of hypoxia itself during development and for the onset of HIF-driven oxygen sensing remains poorly explored. Cellular responses to hypoxia associates with cell immaturity (stemness) and proper tissue and organ development. During mammalian development, the initial uterine environment is hypoxic. The oxygenation status during avian embryogenesis is more complex since O2 continuously equilibrates across the porous eggshell. Here, we investigate HIF dynamics and use microelectrodes to determine O2 concentrations within the egg and the embryo during the first four days of development. To determine the increased O2 consumption rates, we also obtain the O2 transport coefficient (DO2) of eggshell and associated inner and outer shell membranes, both directly (using microelectrodes in ovo for the first time) and indirectly (using water evaporation at 37.5°C for the first time). Our results demonstrate a distinct hypoxic phase (<5% O2) between day 1 and 2, concurring with the onset of HIF-α expression. This phase of hypoxia is demonstrably necessary for proper vascularization and survival. Our indirectly determined DO2 values are about 30% higher than those determined directly. A comparison with previously reported values indicates that this discrepancy may be real, reflecting that water vapor and O2 may be transported through the eggshell at different rates. Based on our obtained DO2 values, we demonstrate that increased O2 consumption of the growing embryo appears to generate the phase of hypoxia, which is also facilitated by the initially small gas cell and low membrane permeability. We infer that the phase of in ovo hypoxia facilitates correct avian development. These results support the view that hypoxic conditions, in which the animal clade evolved, remain functionally important during animal development. The study highlights that insights from the cancer field pertaining to the cellular capacities by which both somatic and cancer cells register and respond to fluctuations in O2 concentrations can broadly inform our exploration of animal development and success.
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| 6. |
- Chavali, Pavithra Lakshminarasimhan, et al.
(författare)
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TLX activates MMP-2, promotes self-renewal of tumor spheres in neuroblastoma and correlates with poor patient survival.
- 2014
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Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 449:5
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear orphan receptor TLX (Drosophila tailless homolog) is essential for the maintenance of neural stem/progenitor cell self-renewal, but its role in neuroblastoma (NB) is not well understood. Here, we show that TLX is essential for the formation of tumor spheres in three different NB cell lines, when grown in neural stem cell media. We demonstrate that the knock down of TLX in IMR-32 cells diminishes its tumor sphere-forming capacity. In tumor spheres, TLX is coexpressed with the neural progenitor markers Nestin, CD133 and Oct-4. In addition, TLX is coexpressed with the migratory neural progenitor markers CD15 and matrix metalloproteinase-2 (MMP-2) in xenografts of primary NB cells from patients. Subsequently, we show the effect of TLX on the proliferative, invasive and migratory properties of IMR-32 cells. We attribute this to the recruitment of TLX to both MMP-2 and Oct-4 gene promoters, which resulted in the respective gene activation. In support of our findings, we found that TLX expression was high in NB patient tissues when compared with normal peripheral nervous system tissues. Further, the Kaplan-Meier estimator indicated a negative correlation between TLX expression and survival in 88 NB patients. Therefore, our results point at TLX being a crucial player in progression of NB, by promoting self-renewal of NB tumor-initiating cells and altering their migratory and invasive properties.
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| 7. |
- Da Silva, Stéphanie, et al.
(författare)
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A novel topical PPARγ agonist induces PPARγ-activity in ulcerative colitis mucosa and prevents and reverses inflammation in induced-colitis models
- 2018
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Ingår i: Inflammatory Bowel Diseases. - : Lippincott Williams & Wilkins. - 1078-0998 .- 1536-4844. ; 24:4, s. 792-805
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Tidskriftsartikel (refereegranskat)abstract
- Background: Peroxisome proliferator-activated receptor-gamma (PPARγ) exerts anti-inflammatory effects and is therefore a potential target in ulcerative colitis (UC). A novel PPARγ agonist (AS002) developed for local action was evaluated ex vivo in biopsies from UC patients and in vivo in mice with low-grade dextran sodium sulfate (DSS)- and trinitrobenzene sulfonic acid (TNBS)-induced colitis.Methods: Colonic biopsies from UC patients (n = 18) and healthy controls (n = 6) were incubated with AS002 or rosiglitazone (positive control) to measure mRNA expression of the PPARγ-responsive gene ADIPOPHILIN and protein levels of UC-related cytokines (enzyme-linked immunosorbent assay). AS002 absorption was determined in the colonic mucosa of UC patients. DSS-colitis mice received PPARγ agonists or vehicle daily by intrarectal administration starting 2 days before induction of colitis (preventive) or from days 3 to 8 (curative). Myeloperoxidase (MPO) and cytokine levels in colonic mucosa were determined. In addition, AS002 effects were studied in TNBS colitis.Results: AS002 displayed an absorption pattern of a lipophilic drug totally metabolized in the mucosa. AS002 and rosiglitazone increased ADIPOPHILIN mRNA expression (3-fold) and decreased TNF-α, IL-1β, and IL-13 levels in human UC biopsies. In DSS, in both preventive and curative treatment and in TNBS colitis, AS002 protected against macroscopic and histological damage and lowered MPO and TNF-α, IL-1β, and IL-13 levels.Conclusions: AS002 triggers anti-inflammatory PPARγ activity in the human colonic mucosa of UC patients and prevents and reverses colitis in mice. Our data suggest that AS002 has potential for topical maintenance treatment of UC, which warrants further studies in vivo in patients.
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| 8. |
- De Santis, Martina M, et al.
(författare)
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Extracellular-Matrix-Reinforced Bioinks for 3D Bioprinting Human Tissue
- 2021
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Ingår i: Advanced Materials. - : Wiley. - 1521-4095 .- 0935-9648. ; 33:3
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in 3D bioprinting allow for generating intricate structures with dimensions relevant for human tissue, but suitable bioinks for producing translationally relevant tissue with complex geometries remain unidentified. Here, a tissue-specific hybrid bioink is described, composed of a natural polymer, alginate, reinforced with extracellular matrix derived from decellularized tissue (rECM). rECM has rheological and gelation properties beneficial for 3D bioprinting while retaining biologically inductive properties supporting tissue maturation ex vivo and in vivo. These bioinks are shear thinning, resist cell sedimentation, improve viability of multiple cell types, and enhance mechanical stability in hydrogels derived from them. 3D printed constructs generated from rECM bioinks suppress the foreign body response, are pro-angiogenic and support recipient-derived de novo blood vessel formation across the entire graft thickness in a murine model of transplant immunosuppression. Their proof-of-principle for generating human tissue is demonstrated by 3D bioprinting human airways composed of regionally specified primary human airway epithelial progenitor and smooth muscle cells. Airway lumens remained patent with viable cells for one month in vitro with evidence of differentiation into mature epithelial cell types found in native human airways. rECM bioinks are a promising new approach for generating functional human tissue using 3D bioprinting.
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| 9. |
- Fredlund, Elina, et al.
(författare)
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MOXD1 is a lineage-specific gene and a tumor suppressor in neuroblastoma
- 2024
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Ingår i: Science Advances. - 2375-2548. ; 10:25
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a childhood developmental cancer; however, its embryonic origins remain poorly understood. Moreover, in-depth studies of early tumor-driving events are limited because of the lack of appropriate models. Herein, we analyzed RNA sequencing data obtained from human neuroblastoma samples and found that loss of expression of trunk neural crest–enriched gene MOXD1 associates with advanced disease and worse outcome. Further, by using single-cell RNA sequencing data of human neuroblastoma cells and fetal adrenal glands and creating in vivo models of zebrafish, chick, and mouse, we show that MOXD1 is a determinate of tumor development. In addition, we found that MOXD1 expression is highly conserved and restricted to mesenchymal neuroblastoma cells and Schwann cell precursors during healthy development. Our findings identify MOXD1 as a lineage-restricted tumor-suppressor gene in neuroblastoma, potentiating further stratification of these tumors and development of novel therapeutic interventions.
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| 10. |
- Gunnarsdóttir, Frida Björk, et al.
(författare)
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Inflammatory macrophage derived TNFα downregulates estrogen receptor α via FOXO3a inactivation in human breast cancer cells
- 2020
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827. ; 390:1
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Tidskriftsartikel (refereegranskat)abstract
- Patients with estrogen receptor α positive (ERα+) breast cancer can respond to endocrine therapy, but treatment resistance is common and associated with downregulation of ERα expression in the dormant residual cells. Here we show, using long-term NSG xenograft models of human breast cancer and primary human monocytes, in vitro primary cell cultures and tumors from breast cancer patients, that macrophage derived tumor necrosis factor alpha (TNFα) downregulates ERα in breast cancer cells via inactivation of the transcription factor Forkhead box O transcription factor 3a (FOXO3a). Moreover, presence of tumor associated macrophages in the primary tumor of breast cancer patients, was associated with ERα negativity, and with worse prognosis in patients with ERα+ tumors. We propose that pro-inflammatory macrophages, despite being tumoricidal, may have direct effects on tumor progression and endocrine resistance in breast cancer patients. Our findings suggest that TNFα antagonists should be evaluated for treatment of ERα+ breast cancer.
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| 11. |
- Hamidian, Arash, et al.
(författare)
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Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome.
- 2015
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 461:3, s. 560-567
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma.
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| 12. |
- Hamidian, Arash, et al.
(författare)
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Promoter-associated proteins of EPAS1 identified by enChIP-MS – A putative role of HDX as a negative regulator
- 2018
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 499:2, s. 291-298
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Tidskriftsartikel (refereegranskat)abstract
- Presence of perivascular neuroblastoma cells with high expression of hypoxia inducible factor (HIF)-2α correlates with distant metastasis and aggressive disease. Regulation of HIFs are traditionally considered to occur post-translationally, but we have recently shown that HIF-2α is unconventionally regulated also at the transcriptional level in neuroblastoma cells. Regulatory factors binding directly to EPAS1 (encoding HIF-2α) to promote transcription are yet to be defined. Here, we employ the novel CRISPR/Cas9-based engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP) – mass spectrometry (MS) methodology to, in an unbiased fashion, identify proteins that associate with the EPAS1 promoter under normoxic and hypoxic conditions. Our enChIP analysis resulted in 27 proteins binding to the EPAS1 promoter in neuroblastoma cells. In agreement with a general hypoxia-driven downregulation of gene transcription, the majority (24 out of 27) of proteins dissociate from the promoter at hypoxia. Among them were several nucleosome-associated proteins suggesting a general opening of chromatin as one explanation to induced EPAS1 transcription at hypoxia. Of particular interest from the list of released factors at hypoxia was the highly divergent homeobox (HDX) transcription factor, that we show inversely correlates with HIF-2α in neuroblastoma cells. We propose a putative model where HDX negatively regulates EPAS1 expression through a release-of-inhibition mechanism.
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| 13. |
- Hammarlund, Emma U., et al.
(författare)
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Oxygen-sensing mechanisms across eukaryotic kingdoms and their roles in complex multicellularity
- 2020
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 370:6515
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Forskningsöversikt (refereegranskat)abstract
- Oxygen-sensing mechanisms of eukaryotic multicellular organisms coordinate hypoxic cellular responses in a spatiotemporal manner. Although this capacity partly allows animals and plants to acutely adapt to oxygen deprivation, its functional and historical roots in hypoxia emphasize a broader evolutionary role. For multicellular life-forms that persist in settings with variable oxygen concentrations, the capacity to perceive and modulate responses in and between cells is pivotal. Animals and higher plants represent the most complex life-forms that ever diversified on Earth, and their oxygen-sensing mechanisms demonstrate convergent evolution from a functional perspective. Exploring oxygen-sensing mechanisms across eukaryotic kingdoms can inform us on biological innovations to harness ever-changing oxygen availability at the dawn of complex life and its utilization for their organismal development.
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| 14. |
- Karakaya, Sinan, et al.
(författare)
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Cytoplasmic HIF-2α as tissue biomarker to identify metastatic sympathetic paraganglioma
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare neuroendocrine tumors. PGLs can further be divided into sympathetic (sPGLs) and head-and-neck (HN-PGLs). There are virtually no treatment options, and no cure, for metastatic PCCs and PGLs (PPGLs). Here, we composed a tissue microarray (TMA) consisting of 149 PPGLs, reflecting clinical features, presenting as a useful resource. Mutations in the pseudohypoxic marker HIF-2 & alpha; correlate to an aggressive tumor phenotype. We show that HIF-2 & alpha; localized to the cytoplasm in PPGLs. This subcompartmentalized protein expression differed between tumor subtypes, and strongly correlated to proliferation. Half of all sPGLs were metastatic at time of diagnosis. Cytoplasmic HIF-2 & alpha; was strongly expressed in metastatic sPGLs and predicted poor outcome in this subgroup. We propose that higher cytoplasmic HIF-2 & alpha; expression could serve as a useful clinical marker to differentiate paragangliomas from pheochromocytomas, and may help predict outcome in sPGL patients.
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| 15. |
- Kerosuo, Laura, et al.
(författare)
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Enhanced expression of MycN/CIP2A drives neural crest toward a neural stem cell-like fate : Implications for priming of neuroblastoma
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 115:31, s. 7351-7360
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a neural crest-derived childhood tumor of the peripheral nervous system in which MycN amplification is a hallmark of poor prognosis. Here we show that MycN is expressed together with phosphorylation-stabilizing factor CIP2A in regions of the neural plate destined to form the CNS, but MycN is excluded from the neighboring neural crest stem cell domain. Interestingly, ectopic expression of MycN or CIP2A in the neural crest domain biases cells toward CNS-like neural stem cells that express Sox2. Consistent with this, some forms of neuroblastoma have been shown to share transcriptional resemblance with CNS neural stem cells. As high MycN/CIP2A levels correlate with poor prognosis, we posit that a MycN/CIP2A-mediated cell-fate bias may reflect a possible mechanism underlying early priming of some aggressive forms of neuroblastoma. In contrast to MycN, its paralogue cMyc is normally expressed in the neural crest stem cell domain and typically is associated with better overall survival in clinical neuroblastoma, perhaps reflecting a more “normal” neural crest-like state. These data suggest that priming for some forms of aggressive neuroblastoma may occur before neural crest emigration from the CNS and well before sympathoadrenal specification.
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| 16. |
- Lindholm, Heléne
(författare)
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Repurposing digitoxin in the treatment of pancreatic ductal adenocarcinoma : genotypic and phenotypic features as biomarkers for digitoxin sensitivity in vitro
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The incidence of pancreatic ductal adenocarcinoma (PDAC) is increasing worldwide. The dismal prognosis and lack of effective treatments urges for increased research efforts in developing new treatment regimens. Since the development of new cancer treatments are expensive and time consuming, repurposing drugs is preferable when possible. This strategy will also be of great value for people in low income countries, to increase the availability of effective cancer treatments to affordable costs. Digitoxin, a cardiac glycoside, has been shown to have anti-cancer effects. It binds to the α subunit of the Na+/K+-ATPase, leading to increased concentrations of intracellular calcium and eventually cell death. There seems also to be other mechanisms elicited in cancer cells by digitoxin. The α subunit occurs in three isoforms, of which α3 has the highest affinity to digitoxin and frequently found over-expressed in tumor cells compared to normal cells.PDAC cancer cells, both cell lines and tumors, differ in their genotype and in the metabolic subtype, proliferation rate and inflammatory status. To be able to individualize treatment regimens it is important to be aware of the specific vulnerabilities (genotypic or phenotypic characteristics increasing the sensitivity to digitoxin) of each PDAC tumor/cell line. This research aims to investigate the potential of using digitoxin as an anti-cancer treatment in PDAC, and analyze its effects on cell viability, metabolism and inflammatory status in PDAC cell lines in vitro with the goal to find biomarkers for digitoxin sensitivity.The analyses of the effects of digitoxin was performed in five cell lines derived from PDAC tumors, either from primary tumors or metastases. Cell lines derived from PDAC are sensitive to digitoxin treatment to different degrees. High expression of α3 seems to be indicative for digitoxin sensitivity, as do a high proliferation rate seen in cell lines derived from primary tumors. Both subunit expression and proliferation rate should be further evaluated in PDAC tumors to confirm their potential to be used as biomarkers clinically.In the hunt for the working mechanism behind the anti-cancer effects of digitoxin, the choline pathway, a pathway commonly affected in tumors was enlightened in the metabolomics study, affected in all five cell lines tested. Choline metabolites are important for maintaining the cell membrane and are involved in energy metabolism using lipids. Digitoxin induced an up-regulation of choline and glycerophosphocholine, which rendered us to propose a novel theory about possible interactions between two functional complexes in the cell membrane, the Na+/K+-ATPase/EGFR/c-Src and the EGFR/c-Src – Chkα. The hypothesis is that when digitoxin binds to the Na+/K+-ATPase it leads to inactivation of Chkα with a subsequent decrease in the synthesis of phosphocholine and phosphatidylcholine. Since cancer cells rely on abundance of choline metabolites, we believe an inhibition of this pathway to be deleterious for these cells.Finally, we conclude that digitoxin has great potential as an anti-cancer treatment for some patients with pancreatic ductal adenocarcinoma. To optimize treatment results, a thorough investigation of the tumor genotype and phenotype must be done for each patient. To further increase treatment success, combination of digitoxin with other treatments for synergistic effects could be beneficial.
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| 17. |
- Mohlin, Sofie, et al.
(författare)
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Anti-tumor effects of PIM/PI3K/mTOR triple kinase inhibitor IBL-302 in neuroblastoma
- 2019
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- The PI3K pathway is a major driver of cancer progression. However, clinical resistance to PI3K inhibition is common. IBL-302 is a novel highly specific triple PIM, PI3K, and mTOR inhibitor. Screening IBL-302 in over 700 cell lines representing 47 tumor types identified neuroblastoma as a strong candidate for PIM/PI3K/mTOR inhibition. IBL-302 was more effective than single PI3K inhibition in vitro, and IBL-302 treatment of neuroblastoma patient-derived xenograft (PDX) cells induced apoptosis, differentiated tumor cells, and decreased N-Myc protein levels. IBL-302 further enhanced the effect of the common cytotoxic chemotherapies cisplatin, doxorubicin, and etoposide. Global genome, proteome, and phospho-proteome analyses identified crucial biological processes, including cell motility and apoptosis, targeted by IBL-302 treatment. While IBL-302 treatment alone reduced tumor growth in vivo, combination therapy with low-dose cisplatin inhibited neuroblastoma PDX growth. Complementing conventional chemotherapy treatment with PIM/PI3K/mTOR inhibition has the potential to improve clinical outcomes and reduce severe late effects in children with high-risk neuroblastoma.
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| 18. |
- Mohlin, Sofie, et al.
(författare)
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HIF2A and IGF2 Expression Correlates in Human Neuroblastoma Cells and Normal Immature Sympathetic Neuroblasts.
- 2013
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Ingår i: Neoplasia. - : Elsevier BV. - 1522-8002 .- 1476-5586. ; 15:3, s. 328-334
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Tidskriftsartikel (refereegranskat)abstract
- During normal sympathetic nervous system (SNS) development, cells of the ganglionic lineage can malignantly transform and develop into the childhood tumor neuroblastoma. Hypoxia-inducible transcription factors (HIFs) mediate cellular responses during normal development and are central in the adaptation to oxygen shortage. HIFs are also implicated in the progression of several cancer forms, and high HIF-2α expression correlates with disseminated disease and poor outcome in neuroblastoma. During normal SNS development, is transiently expressed in neuroblasts and chromaffin cells. SNS cells can, during development, be distinguished by distinct gene expression patterns, and () is a marker of sympathetic chromaffin cells, whereas sympathetic neuroblasts lack expression. Despite the neuronal derivation of neuroblastomas, we show that neuroblastoma cell lines and specimens express and that expression of and correlates, with the strongest correlation in high-stage tumors. In neuroblastoma, both and are hypoxia-driven and knocking down at hypoxia resulted in downregulated levels. HIF-2α and were strongly expressed in subsets of immature neuroblastoma cells, suggesting that these two genes could be co-expressed also at early stages of SNS development. We show that is indeed expressed in sympathetic chain ganglia at embryonic week 6.5, a developmental stage when HIF-2α is present. These findings provide a rationale for the unexpected expression in neuroblastomas and might suggest that and positive neuroblastoma cells are arrested at an embryonic differentiation stage corresponding to the stage when sympathetic chain ganglia begins to coalesce.
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| 19. |
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| 20. |
- Mohlin, Sofie, et al.
(författare)
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Hypoxia, pseudohypoxia and cellular differentiation
- 2017
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827. ; 356:2, s. 192-196
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Tidskriftsartikel (refereegranskat)abstract
- Tumor hypoxia correlates to aggressive disease, and while this is explained by a variety of factors, one clue to understand this phenomena was the finding that hypoxia induces a de-differentiated, stem cell-like phenotype in neuroblastoma and breast tumor cells. The hypoxia inducible transcription factors (HIFs) are regulated at the translational level by fluctuating oxygen concentrations, but emerging data reveal that both HIF-1α and HIF-2α expression can be induced by aberrantly activated growth factor signaling independently of oxygen levels. Furthermore, HIF-2α is regulated by hypoxia also at the transcriptional level in neuroblastoma and glioma cells. In cultured tumor cells, HIF-2α is stabilized at physiological oxygen concentrations followed by induced expression of classical hypoxia-driven genes, resulting in a pseudohypoxic phenotype. In addition, in neuroblastoma and glioma specimens, a small subset of HIF-2α positive, HIF-1α negative, tumor cells is found adjacent to blood vessels, i.e. in areas with presumably adequate oxygenation. These tumor niches are thus pseudohypoxic, and the HIF-2α expressing cells present immature features. We have postulated that this niche in neuroblastomas encompass the tumor stem cells. Oncogenes or tumor suppressor genes associated with pseudohypoxia are frequently mutated or deleted in the germline, implicating that the pseudohypoxic phenotype indeed is tumorigenic. In summary, the hypoxic and pseudohypoxic phenotypes of solid tumors are attractive therapeutic targets.
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| 21. |
- Mohlin, Sofie
(författare)
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IGF, PI3K and HIF-2 in Normal and Tumor Development
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cells adapt to oxygen shortage, hypoxia, by inducing a transcriptional shift governed mainly by Hypoxia Inducible Factor (HIF)-1 and HIF-2. In various cancer forms, including neuroblastoma, high expression of HIF-2α correlates with disseminated disease and poor outcome. It has become evident that HIF-1 and HIF-2 are differentially regulated over time and by oxygen levels. HIF-2α is expressed in a subset of perivascularly located neuroblastoma cells in vivo and appear to be co-expressed with markers of early sympathetic nervous system development, while HIF-1α expression is restricted to necrotic and hypoxic tumor areas. Here, we demonstrate that HIF-2α is regulated at the transcriptional level by the IGF and PI3K signaling pathways, two pathways commonly deregulated in human cancer. In addition, the expression of HIF-2α and IGF-II correlates in neuroblastoma specimens and cell lines, and the finding that HIF-2α and IGF-II are co-expressed in sympathetic neuroblasts during early human development (embryonic week 6.5) suggest that neuroblastoma cells are arrested at a differentiation stage corresponding to when sympathetic chain ganglia begin to coalesce. We further show that the differential regulation of HIF-1α and HIF-2α in neuroblastoma partly can be explained by specific IGF and PI3K-mTOR signaling. While HIF-1α is exclusively regulated at the translational level via mTOR complex 1 (mTORC1) at hypoxia, HIF-2α is regulated at the transcriptional level by mTORC2, providing an opportunity to specifically target the HIF-2α-driven aggressive phenotype in neuroblastoma. At last, PI3K is composed of a regulatory and a catalytic domain, and we highlight the complexity of this signaling pathway by identifying the catalytic subunit, p110δ, responsible for c-Kit mediated cell transformation, and the process of kinase-dependent and –independent activation.
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| 22. |
- Mohlin, Sofie, et al.
(författare)
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In vitro maintenance of multipotent neural crest stem cells as crestospheres
- 2019
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Ingår i: Methods in Molecular Biology. - New York, NY : Springer New York. - 1064-3745. - 9781493995073 ; 2002, s. 1-11
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Bokkapitel (refereegranskat)abstract
- Neural crest cells are a critical source of many cell types of the vertebrate body. However, as a stem cell population they are peculiar because of the transient nature of their stem cell niche; soon after the multipotent neural crest cells are specified in the neuroepithelium, they become mesenchymal cells that migrate into various destinations in early embryos. These rapid in vivo changes during neural crest development complicate the studies on their stem cell properties. Crestospheres are in vitro maintained primary cultures of premigratory neural crest cells that maintain a mixture of neural crest stem and progenitor cells for weeks without spontaneous differentiation, including the multipotent neural crest stem cells. Here, we describe how crestosphere cultures are initiated from either cranial or trunk levels of chick embryos. Alternatively, the same culture conditions can be used to maintain human embryonic stem cell-derived neural crest cells as crestospheres. Thus, crestospheres provide a useful tool for studies on neural crest stemness.
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| 23. |
- Mohlin, Sofie, et al.
(författare)
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Maintaining multipotent trunk neural crest stem cells as self-renewing crestospheres
- 2019
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Ingår i: Developmental Biology. - : Elsevier BV. - 0012-1606. ; 447:2, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- Neural crest cells have broad migratory and differentiative ability that differs according to their axial level of origin. However, their transient nature has limited understanding of their stem cell and self-renewal properties. While an in vitro culture method has made it possible to maintain cranial neural crest cells as self-renewing multipotent crestospheres (Kerosuo et al., 2015), these same conditions failed to preserve trunk neural crest in a stem-like state. Here we optimize culture conditions for maintenance of avian trunk crestospheres, comprised of both neural crest stem and progenitor cells. Our trunk-derived crestospheres are multipotent and display self-renewal capacity over several weeks. Trunk crestospheres display elevated expression of neural crest cell markers as compared to those characteristic of ventrolateral neural tube or mesodermal fates. Moreover, trunk crestospheres express increased levels of trunk neural crest-enriched markers as compared to cranial crestospheres. Finally, we use lentiviral transduction as a tool to manipulate gene expression in trunk crestospheres. Taken together, this method enables long-term in vitro maintenance and manipulation of multipotent trunk neural crest cells in a premigratory stem or early progenitor state. Trunk crestospheres are a valuable resource for probing mechanisms underlying neural crest stemness and lineage decisions as well as accompanying diseases.
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| 24. |
- Mohlin, Sofie, et al.
(författare)
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Neuroblastoma aggressiveness in relation to sympathetic neuronal differentiation stage.
- 2011
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Ingår i: Seminars in Cancer Biology. - : Elsevier BV. - 1096-3650 .- 1044-579X. ; 21:4, s. 276-282
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a childhood malignancy of the sympathetic neuronal lineage. It is a rare disease, but since it is frequently diagnosed during infancy, neuroblastoma causes life-long medical follow up of those children that survive the disease. It was early recognized that a high tumor cell differentiation stage correlates to favorable clinical stage and positive clinical outcome. Today, highly differentiated tumors are surgically removed and not further treated. Cells of many established human neuroblastoma cell lines have the capacity to differentiate when stimulated properly, and these cell lines have been used as models for studying and understanding central concepts of tumor cell differentiation. One recent aspect of this issue is the observation that tumor cells can dedifferentiate and gain a stem cell-like phenotype during hypoxic conditions, which was first shown in neuroblastoma. Aberrant or blocked differentiation is a central aspect of neuroblastoma genesis. In this review we summarize known genetic and non-genetic events in neuroblastoma that might be coupled to an aberrant sympathetic neuronal differentiation and thereby indirectly influencing tumorigenesis and/or aggressive neuroblastoma behavior.
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| 25. |
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