Publications by authors named "Monica Nistér"

78 Publications

VEGFR2 inhibition hampers breast cancer cell proliferation enhanced mitochondrial biogenesis.

Cancer Biol Med 2021 Feb;18(1):139-154

Karolinska Institutet, Department of Medicine-Solna, Clinical Pharmacology Group, Karolinska University Hospital-Solna, Stockholm 17176, Sweden.

Objective: Vascular endothelial growth factor (VEGF), apart from its predominant roles in angiogenesis, can enhance cancer cell proliferation, but its mechanisms remain elusive. The purpose of the present study was therefore to identify how VEGF regulates cancer cell proliferation.

Methods: VEGF effects on cancer cell proliferation were investigated with the VEGF receptor 2 inhibitor, Ki8751, and the breast cancer cell lines, MCF-7 and MDA-MB-231, using flow cytometry, mass spectrometry, immunoblotting, and confocal microscopy. Data were analyzed using one-way analysis of variance followed by Tukey's multiple comparison test.

Results: VEGF blockade by Ki8751 significantly reduced cancer cell proliferation, and enhanced breast cancer cell apoptosis. Mass spectrometric analyses revealed that Ki8751 treatment significantly upregulated the expression of mitochondrial proteins, suggesting the involvement of mitochondrial biogenesis. Confocal microscopy and flow cytometric analyses showed that Ki8751 treatment robustly increased the mitochondrial masses of both cancer cells, induced endomitosis, and arrested cancer cells in the high aneuploid phase. VEGFR2 knockdown by shRNAs showed similar effects to those of Ki8751, confirming the specificity of Ki8751 treatment. Enhanced mitochondrial biogenesis increased mitochondrial oxidative phosphorylation and stimulated reactive oxygen species (ROS) production, which induced cancer cell apoptosis. Furthermore, Ki8751 treatment downregulated the phosphorylation of Akt and PGC1α, and translocated PGC1α into the nucleus. The PGC1α alterations increased mitochondrial transcription factor A (TFAM) expression and subsequently increased mitochondrial biogenesis.

Conclusions: VEGF enhances cancer cell proliferation by decreasing Akt-PGC1α-TFAM signaling-mediated mitochondrial biogenesis, ROS production, and cell apoptosis. These findings suggested the anticancer potential of Ki8751 increased mitochondrial biogenesis and ROS production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.20892/j.issn.2095-3941.2020.0151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877175PMC
February 2021

Enrichment of branched chain amino acid transaminase 1 correlates with multiple biological processes and contributes to poor survival of IDH1 wild-type gliomas.

Aging (Albany NY) 2021 01 20;13(3):3645-3660. Epub 2021 Jan 20.

Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China.

Previous studies have reported the association between branched-chain amino acid trasaminase1 (BCAT1) and IDH1 wild-type gliomas. Nonetheless, as a promising target for treatment of primary glioblastoma, comprehensive reports on BCAT1 in gliomas are still lacking. In the present study, we accessed glioma patient cohorts and tissue microarray to evaluate the expression pattern of BCAT1 for determining its prognostic value and its relationship with IDH1 mutation status. Furthermore, we explored the potential regulatory mechanism of BCAT1 in gliomas by comparing the BCAT1 mRNA expression pattern with selected tumor biological signatures. The results showed that BCAT1 is highly expressed in GBM versus lower grade gliomas and could represent the poor survival of IDH1 wild-type gliomas. Moreover, BCAT1 is an independent prognostic factor for glioma patients, high BCAT1 expression is related to unfavorable clinical parameters including older age, IDH wildtype, no 1p/19q codeletion, ATRX wildtype and MGMT unmethylated. Additionally, BCAT1 correlated with apoptosis, hypoxia and angiogenesis processes in gliomas and high expression of BCAT1 revealed higher glycolysis level and increased immunosuppressive status in tumor progression. We concluded that BCAT1 is a strong prognostic factor for glioma patients and involved in the malignant progression of IDH1 wild-type gliomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/aging.202328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906175PMC
January 2021

The spatial RNA integrity number assay for in situ evaluation of transcriptome quality.

Commun Biol 2021 Jan 8;4(1):57. Epub 2021 Jan 8.

Science for Life Laboratory, KTH - Royal Institute of Technology (KTH), SE-171 65, Solna, Sweden.

The RNA integrity number (RIN) is a frequently used quality metric to assess the completeness of rRNA, as a proxy for the corresponding mRNA in a tissue. Current methods operate at bulk resolution and provide a single average estimate for the whole sample. Spatial transcriptomics technologies have emerged and shown their value by placing gene expression into a tissue context, resulting in transcriptional information from all tissue regions. Thus, the ability to estimate RNA quality in situ has become of utmost importance to overcome the limitation with a bulk rRNA measurement. Here we show a new tool, the spatial RNA integrity number (sRIN) assay, to assess the rRNA completeness in a tissue wide manner at cellular resolution. We demonstrate the use of sRIN to identify spatial variation in tissue quality prior to more comprehensive spatial transcriptomics workflows.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s42003-020-01573-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794352PMC
January 2021

Sarek: A portable workflow for whole-genome sequencing analysis of germline and somatic variants.

F1000Res 2020 29;9:63. Epub 2020 Jan 29.

Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Husargatan 3, Uppsala, 752 37, Sweden.

Whole-genome sequencing (WGS) is a fundamental technology for research to advance precision medicine, but the limited availability of portable and user-friendly workflows for WGS analyses poses a major challenge for many research groups and hampers scientific progress. Here we present Sarek, an open-source workflow to detect germline variants and somatic mutations based on sequencing data from WGS, whole-exome sequencing (WES), or gene panels. Sarek features (i) easy installation, (ii) robust portability across different computer environments, (iii) comprehensive documentation, (iv) transparent and easy-to-read code, and (v) extensive quality metrics reporting. Sarek is implemented in the Nextflow workflow language and supports both Docker and Singularity containers as well as Conda environments, making it ideal for easy deployment on any POSIX-compatible computers and cloud compute environments. Sarek follows the GATK best-practice recommendations for read alignment and pre-processing, and includes a wide range of software for the identification and annotation of germline and somatic single-nucleotide variants, insertion and deletion variants, structural variants, tumour sample purity, and variations in ploidy and copy number. Sarek offers easy, efficient, and reproducible WGS analyses, and can readily be used both as a production workflow at sequencing facilities and as a powerful stand-alone tool for individual research groups. The Sarek source code, documentation and installation instructions are freely available at https://github.com/nf-core/sarek and at https://nf-co.re/sarek/.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12688/f1000research.16665.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7111497PMC
February 2021

Identification of functionally distinct and interacting cancer cell subpopulations from glioblastoma with intratumoral genetic heterogeneity.

Neurooncol Adv 2020 Jan-Dec;2(1):vdaa061. Epub 2020 May 27.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.

Background: Glioblastomas display a high level of intratumoral heterogeneity with regard to both genetic and histological features. Within single tumors, subclones have been shown to communicate with each other to affect overall tumor growth. The aim of this study was to broaden the understanding of interclonal communication in glioblastoma.

Methods: We have used the U-343 model, consisting of U-343 MG, U-343 MGa, U-343 MGa 31L, and U-343 MGa Cl2:6, a set of distinct glioblastoma cell lines that have been derived from the same tumor. We characterized these with regard to temozolomide sensitivity, protein secretome, gene expression, DNA copy number, and cancer cell phenotypic traits. Furthermore, we performed coculture and conditioned media-based experiments to model cell-to-cell signaling in a setting of intratumoral heterogeneity.

Results: Temozolomide treatment of a coculture composed of all 4 U-343 cell lines presents a tumor relapse model where the least sensitive population, U-343 MGa 31L, outlives the others. Interestingly, the U-343 cell lines were shown to have distinct gene expression signatures and phenotypes although they were derived from a single tumor. The DNA copy number analysis revealed both common and unique alterations, indicating the evolutionary relationship between the cells. Moreover, these cells were found to communicate and affect each other's proliferation, both via contact-dependent and -independent interactions, where NOTCH1, TGFBI, and ADAMTS1 signaling effects were involved, respectively.

Conclusions: These results provide insight into how complex the signaling events may prove to be in a setting of intratumoral heterogeneity in glioblastoma and provide a map for future studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/noajnl/vdaa061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309246PMC
May 2020

Regulation of Mammalian Mitochondrial Dynamics: Opportunities and Challenges.

Front Endocrinol (Lausanne) 2020 11;11:374. Epub 2020 Jun 11.

Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden.

Mitochondria are highly dynamic organelles and important for a variety of cellular functions. They constantly undergo fission and fusion events, referred to as mitochondrial dynamics, which affects the shape, size, and number of mitochondria in the cell, as well as mitochondrial subcellular transport, mitochondrial quality control (mitophagy), and programmed cell death (apoptosis). Dysfunctional mitochondrial dynamics is associated with various human diseases. Mitochondrial dynamics is mediated by a set of mitochondria-shaping proteins in both yeast and mammals. In this review, we describe recent insights into the potential molecular mechanisms underlying mitochondrial fusion and fission, particularly highlighting the coordinating roles of different mitochondria-shaping proteins in the processes, as well as the roles of the endoplasmic reticulum (ER), the actin cytoskeleton and membrane phospholipids in the regulation of mitochondrial dynamics. We particularly focus on emerging roles for the mammalian mitochondrial proteins Fis1, Mff, and MIEFs (MIEF1 and MIEF2) in regulating the recruitment of the cytosolic Drp1 to the surface of mitochondria and how these proteins, especially Fis1, mediate crosstalk between the mitochondrial fission and fusion machineries. In summary, this review provides novel insights into the molecular mechanisms of mammalian mitochondrial dynamics and the involvement of these mechanisms in apoptosis and autophagy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fendo.2020.00374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300174PMC
June 2020

Platelet-derived growth factor receptor α/glial fibrillary acidic protein expressing peritumoral astrocytes associate with shorter median overall survival in glioblastoma patients.

Glia 2020 05 26;68(5):979-988. Epub 2019 Nov 26.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.

The microenvironment and architecture of peritumoral tissue have been suggested to affect permissiveness for infiltration of malignant cells. Astrocytes constitute a heterogeneous population of cells and have been linked to proliferation, migration, and drug sensitivity of glioblastoma (GBM) cells. Through double-immunohistochemical staining for platelet-derived growth factor receptor α (PDGFRα) and glial fibrillary acidic protein (GFAP), this study explored the intercase variability among 45 human GBM samples regarding density of GFAP+ peritumoral astrocytes and a subset of GFAP+ peritumoral astrocyte-like cells also expressing PDGFRα. Large intercase variability regarding the total peritumoral astrocyte density and the density of PDGFRα+/GFAP+ peritumoral astrocyte-like cells was detected. DNA fluorescence in situ hybridization analyses for commonly altered genetic tumor markers supported the interpretation that these cells represented a genetically unaffected host cell subset referred to as PDGFRα+/GFAP+ peritumoral astrocytes. The presence of PDGFRα+/GFAP+ peritumoral astrocytes was significantly positively correlated to older patient age and peritumoral astrocyte density, but not to other established prognostic factors. Notably, presence of PDGFRα+/GFAP+ peritumoral astrocytes, but not peritumoral astrocyte density, was associated with significantly shorter patient overall survival. The prognostic association of PDGFRα+/GFAP+ peritumoral astrocytes was confirmed in multivariable analyses. This exploratory study thus demonstrates previously unrecognized intercase variability and prognostic significance of peritumoral abundance of a novel PDGFRα+ subset of GFAP+ astrocytes. Findings suggest clinically relevant roles of the microenvironment of peritumoral GBM tissue and encourage further characterization of the novel astrocyte subset with regard to origin, function, and potential as biomarker and drug target.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.23756DOI Listing
May 2020

The phosphorylation status of Ser-637 in dynamin-related protein 1 (Drp1) does not determine Drp1 recruitment to mitochondria.

J Biol Chem 2019 11 18;294(46):17262-17277. Epub 2019 Sep 18.

Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden

Recruitment of the GTPase dynamin-related protein 1 (Drp1) to mitochondria is a central step required for mitochondrial fission. Reversible Drp1 phosphorylation has been implicated in the regulation of this process, but whether Drp1 phosphorylation at Ser-637 determines its subcellular localization and fission activity remains to be fully elucidated. Here, using HEK 293T cells and immunofluorescence, immunoblotting, RNAi, subcellular fractionation, co-immunoprecipitation assays, and CRISPR/Cas9 genome editing, we show that Drp1 phosphorylated at Ser-637 (Drp1) resides both in the cytosol and on mitochondria. We found that the receptors mitochondrial fission factor (Mff) and mitochondrial elongation factor 1/2 (MIEF1/2) interact with and recruit Drp1 to mitochondria and that elevated Mff or MIEF levels promote Drp1 accumulation on mitochondria. We also noted that protein kinase A (PKA), which mediates phosphorylation of Drp1 on Ser-637, is partially present on mitochondria and interacts with both MIEFs and Mff. PKA knockdown did not affect the Drp1-Mff interaction, but slightly enhanced the interaction between Drp1 and MIEFs. In Drp1-deficient HEK 293T cells, both phosphomimetic Drp1-S637D and phospho-deficient Drp1-S637A variants, like wild-type Drp1, located to the cytosol and to mitochondria and rescued a Drp1 deficiency-induced mitochondrial hyperfusion phenotype. However, Drp1-S637D was less efficient than Drp1-WT and Drp1-S637A in inducing mitochondrial fission. In conclusion, the Ser-637 phosphorylation status in Drp1 is not a determinant that controls Drp1 recruitment to mitochondria.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA119.008202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6873174PMC
November 2019

Astrocytes enhance glioblastoma growth.

Glia 2020 02 11;68(2):316-327. Epub 2019 Sep 11.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.

Glioblastoma (GBM) is a deadly disease with a need for deeper understanding and new therapeutic approaches. The microenvironment of glioblastoma has previously been shown to guide glioblastoma progression. In this study, astrocytes were investigated with regard to their effect on glioblastoma proliferation through correlative analyses of clinical samples and experimental in vitro and in vivo studies. Co-culture techniques were used to investigate the GBM growth enhancing potential of astrocytes. Cell sorting and RNA sequencing were used to generate a GBM-associated astrocyte signature and to investigate astrocyte-induced GBM genes. A NOD scid GBM mouse model was used for in vivo studies. A gene signature reflecting GBM-activated astrocytes was associated with poor prognosis in the TCGA GBM dataset. Two genes, periostin and serglycin, induced in GBM cells upon exposure to astrocytes were expressed at higher levels in cases with high "astrocyte signature score". Astrocytes were shown to enhance glioblastoma cell growth in cell lines and in a patient-derived culture, in a manner dependent on cell-cell contact and involving increased cell proliferation. Furthermore, co-injection of astrocytes with glioblastoma cells reduced survival in an orthotopic GBM model in NOD scid mice. In conclusion, this study suggests that astrocytes contribute to glioblastoma growth and implies this crosstalk as a candidate target for novel therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/glia.23718DOI Listing
February 2020

EglN3 hydroxylase stabilizes BIM-EL linking VHL type 2C mutations to pheochromocytoma pathogenesis and chemotherapy resistance.

Proc Natl Acad Sci U S A 2019 08 2;116(34):16997-17006. Epub 2019 Aug 2.

Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden;

Despite the discovery of the oxygen-sensitive regulation of HIFα by the von Hippel-Lindau (VHL) protein, the mechanisms underlying the complex genotype/phenotype correlations in VHL disease remain unknown. Some germline mutations cause familial pheochromocytoma and encode proteins that preserve their ability to down-regulate HIFα. While type 1, 2A, and 2B mutants are defective in regulating HIFα, type 2C mutants encode proteins that preserve their ability to down-regulate HIFα. Here, we identified an oxygen-sensitive function of VHL that is abolished by type 2C mutations. We found that BIM-EL, a proapoptotic BH3-only protein, is hydroxylated by EglN3 and subsequently bound by VHL. VHL mutants fail to bind hydroxylated BIM-EL, regardless of whether they have the ability to bind hydroxylated HIFα or not. VHL binding inhibits BIM-EL phosphorylation by extracellular signal-related kinase (ERK) on serine 69. This causes BIM-EL to escape from proteasomal degradation, allowing it to enhance EglN3-induced apoptosis. BIM-EL was rapidly degraded in cells lacking wild-type VHL or in which EglN3 was inactivated genetically or by lack of oxygen, leading to enhanced cell survival and chemotherapy resistance. Combination therapy using ERK inhibitors, however, resensitizes VHL- and EglN3-deficient cells that are otherwise cisplatin-resistant.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1900748116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6708352PMC
August 2019

Human Fis1 regulates mitochondrial dynamics through inhibition of the fusion machinery.

EMBO J 2019 04 6;38(8). Epub 2019 Mar 6.

Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden

Mitochondrial dynamics is important for life. At center stage for mitochondrial dynamics, the balance between mitochondrial fission and fusion is a set of dynamin-related GTPases that drive mitochondrial fission and fusion. Fission is executed by the GTPases Drp1 and Dyn2, whereas the GTPases Mfn1, Mfn2, and OPA1 promote fusion. Recruitment of Drp1 to mitochondria is a critical step in fission. In yeast, Fis1p recruits the Drp1 homolog Dnm1p to mitochondria through Mdv1p and Caf4p, but whether human Fis1 (hFis1) promotes fission through a similar mechanism as in yeast is not established. Here, we show that hFis1-mediated mitochondrial fragmentation occurs in the absence of Drp1 and Dyn2, suggesting that they are dispensable for hFis1 function. hFis1 instead binds to Mfn1, Mfn2, and OPA1 and inhibits their GTPase activity, thus blocking the fusion machinery. Consistent with this, disruption of the fusion machinery in Drp1 cells phenocopies the fragmentation phenotype induced by hFis1 overexpression. In sum, our data suggest a novel role for hFis1 as an inhibitor of the fusion machinery, revealing an important functional evolutionary divergence between yeast and mammalian Fis1 proteins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embj.201899748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463211PMC
April 2019

Reduced Expression of PROX1 Transitions Glioblastoma Cells into a Mesenchymal Gene Expression Subtype.

Cancer Res 2018 10 22;78(20):5901-5916. Epub 2018 Aug 22.

Cancer Center Karolinska, Department of Oncology-Pathology, Karolinska Institutet and Karolinska University Hospital at Solna, Stockholm, Sweden.

The homeodomain transcription factor PROX1 has been linked to several cancer types, including gliomas, but its functions remain to be further elucidated. Here we describe a functional role and the prognostic value of PROX1 in glioblastoma. Low expression of correlated with poor overall survival and the mesenchymal glioblastoma subtype signature. The latter finding was recapitulated , where suppression or overexpression of PROX1 in glioma cell cultures transitioned cells to a mesenchymal or to a nonmesenchymal glioblastoma gene expression signature, respectively. PROX1 modulation affected proliferation rates that coincided with changes in protein levels of CCNA1 and CCNE1 as well as the cyclin inhibitors CDKN1A, CDKN1B, and CDKN1C. Overexpression of SOX2 increased PROX1 expression, but treatment with a CDK2 inhibitor subsequently decreased PROX1 expression, which was paralleled by decreased SOX2 levels. The THRAP3 protein was a novel binding partner for PROX1, and suppression of THRAP3 increased both transcript and protein levels of PROX1. Together, these findings highlight the prognostic value of PROX1 and its role as a regulator of glioblastoma gene expression subtypes, intratumoral heterogeneity, proliferation, and cell-cycle control. These findings demonstrate the role and prognostic value of PROX1 in glioblastomas; low PROX1 levels correlate with a mesenchymal gene expression subtype and shorter survival in glioblastoma tumors. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-18-0320DOI Listing
October 2018

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis.

Hum Reprod 2018 10;33(10):1924-1938

Division of Obstetrics and Gynecology, Department of Women's and Children's Health, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden.

Study Question: Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

Study Answer: We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

What Is Known Already: Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

Study Design, Size, Duration: CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

Participants/materials, Settings, Methods: Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

Main Results And The Role Of Chance: Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

Large-scale Data: N/A.

Limitations, Reason For Caution: As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

Wider Implications Of The Findings: Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

Study Funding/competing Interest(s): The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/humrep/dey241DOI Listing
October 2018

Glycosylation controls sodium-calcium exchanger 3 sub-cellular localization during cell cycle.

Eur J Cell Biol 2018 Apr 28;97(3):190-203. Epub 2018 Feb 28.

Department of Oncology-Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden. Electronic address:

The Na/Ca exchanger (NCX) is a membrane antiporter that has been identified in the plasma membrane, the inner membrane of the nuclear envelope and in the membrane of the endoplasmic reticulum (ER). In humans, three genes have been identified, encoding unique NCX proteins. Although extensively studied, the NCX's sub-cellular localization and mechanisms regulating the activity of different subtypes are still ambiguous. Here we investigated the subcellular localization of the NCX subtype 3 (NCX3) and its impact on the cell cycle. Two phenotypes, switching from one to the other during the cell cycle, were detected. One phenotype was NCX3 in the plasma membrane during S and M phase, and the other was NCX3 in the ER membrane during resting and interphase. Glycosylation of NCX3 at the N45 site was required for targeting the protein to the plasma membrane, and the N45 site functioned as an on-off switch for the translocation of NCX3 to either the plasma membrane or the membrane of the ER. Introduction of an N-glycosylation deficient NCX3 mutant led to an arrest of cells in the G0/G1 phase of the cell cycle. This was accompanied by accumulation of de-glycosylated NCX3 in the cytosol (that is in the ER), where it transported calcium ions (Ca) from the cytosol to the ER. These results, obtained in transfected HEK293T and HeLa and confirmed endogenously in SH-SY5Y cells, suggest that cells can use a dynamic Ca signaling toolkit in which the NCX3 sub-cellular localization changes in synchrony with the cell cycle.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejcb.2018.02.004DOI Listing
April 2018

SOX5/6/21 Prevent Oncogene-Driven Transformation of Brain Stem Cells.

Cancer Res 2017 09 7;77(18):4985-4997. Epub 2017 Jul 7.

Ludwig Institute for Cancer Research, Stockholm, Sweden.

Molecular mechanisms preventing self-renewing brain stem cells from oncogenic transformation are poorly defined. We show that the expression levels of SOX5, SOX6, and SOX21 (SOX5/6/21) transcription factors increase in stem cells of the subventricular zone (SVZ) upon oncogenic stress, whereas their expression in human glioma decreases during malignant progression. Elevated levels of SOX5/6/21 promoted SVZ cells to exit the cell cycle, whereas genetic ablation of SOX5/6/21 dramatically increased the capacity of these cells to form glioma-like tumors in an oncogene-driven mouse brain tumor model. Loss-of-function experiments revealed that SOX5/6/21 prevent detrimental hyperproliferation of oncogene expressing SVZ cells by facilitating an antiproliferative expression profile. Consistently, restoring high levels of SOX5/6/21 in human primary glioblastoma cells enabled expression of CDK inhibitors and decreased p53 protein turnover, which blocked their tumorigenic capacity through cellular senescence and apoptosis. Altogether, these results provide evidence that SOX5/6/21 play a central role in driving a tumor suppressor response in brain stem cells upon oncogenic insult. .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-17-0704DOI Listing
September 2017

MIEF1/2 function as adaptors to recruit Drp1 to mitochondria and regulate the association of Drp1 with Mff.

Sci Rep 2017 04 13;7(1):880. Epub 2017 Apr 13.

Department of Oncology-Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76, Stockholm, Sweden.

Mitochondrial dynamics is a fundamental cellular process and recruitment of Drp1 to mitochondria is an essential step in mitochondrial fission. Mff and MIEF1/2 (MiD51/49) serve as key receptors for recruitment of Drp1 to mitochondria in mammals. However, if and how these receptors work together in mitochondrial fission is poorly understood. Here we show that MIEFs interact with both Drp1 and Mff on the mitochondrial surface and serve as adaptors linking Drp1 and Mff together in a trimeric Drp1-MIEF-Mff complex. Thus, MIEFs can regulate the interaction between Drp1 and Mff, and also Mff-induced Drp1 accumulation on mitochondria. It is shown that loss of endogenous MIEFs severely impairs these processes. Additionally, in cells depleted of endogenous MIEF1/2, high levels of exogenous MIEFs sequester Drp1 on the mitochondrial surface, resulting in mitochondrial elongation, whereas low-to-moderate levels of MIEFs promote mitochondrial fission, leading to mitochondrial fragmentation. In sum, the data suggest that MIEFs and Mff work coordinately in Drp1-mediated mitochondrial fission and that the level of MIEF1/2 relative to Mff sets the balance between mitochondrial fission and fusion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-00853-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429825PMC
April 2017

Erratum to: Identification of mutations, gene expression changes and fusion transcripts by whole transcriptome RNAseq in docetaxel resistant prostate cancer cells.

Springerplus 2016 8;5(1):2084. Epub 2016 Dec 8.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden ; Department of Clinical Oncology, Karolinska University Hospital, Stockholm, Sweden.

[This corrects the article DOI: 10.1186/s40064-016-3543-0.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40064-016-3759-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5143331PMC
December 2016

Identification of mutations, gene expression changes and fusion transcripts by whole transcriptome RNAseq in docetaxel resistant prostate cancer cells.

Springerplus 2016 24;5(1):1861. Epub 2016 Oct 24.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden ; Department of Clinical Oncology, Karolinska University Hospital, Stockholm, Sweden.

Docetaxel has been the standard first-line therapy in metastatic castration resistant prostate cancer. The survival benefit is, however, limited by either primary or acquired resistance. In this study, Du145 prostate cancer cells were converted to docetaxel-resistant cells Du145-R and Du145-RB by in vitro culturing. Next generation RNAseq was employed to analyze these cell lines. Forty-two genes were identified to have acquired mutations after the resistance development, of which thirty-four were found to have mutations in published sequencing studies using prostate cancer samples from patients. Fourteen novel and 2 previously known fusion genes were inferred from the RNA-seq data, and 13 of these were validated by RT-PCR and/or re-sequencing. Four in-frame fusion transcripts could be transcribed into fusion proteins in stably transfected HEK293 cells, including MYH9-EIF3D and LDLR-RPL31P11, which were specific identified or up-regulated in the docetaxel resistant DU145 cells. A panel of 615 gene transcripts was identified to have significantly changed expression profile in the docetaxel resistant cells. These transcriptional changes have potential for further study as predictive biomarkers and as targets of docetaxel treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40064-016-3543-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5078122PMC
October 2016

PROX1 is a novel pathway-specific prognostic biomarker for high-grade astrocytomas; results from independent glioblastoma cohorts stratified by age and IDH mutation status.

Oncotarget 2016 Nov;7(45):72431-72442

Department of Neuroscience, Neurology, Uppsala University, University Hospital, Uppsala, Sweden.

PROX1 is a transcription factor with an essential role in embryonic development and determination of cell fate. In addition, PROX1 has been ascribed suppressive as well as oncogenic roles in several human cancers, including brain tumors. In this study we explored the correlation between PROX1 expression and patient survival in high-grade astrocytomas. For this purpose, we analyzed protein expression in tissue microarrays of tumor samples stratified by patient age and IDH mutation status. We initially screened 86 unselected high-grade astrocytomas, followed by 174 IDH1-R132H1 immunonegative glioblastomas derived from patients aged 60 years and older enrolled in the Nordic phase III trial of elderly patients with newly diagnosed glioblastoma. Representing the younger population of glioblastomas, we studied 80 IDH-wildtype glioblastomas from patients aged 18-60 years. There was no correlation between PROX1 protein and survival for patients with primary glioblastomas included in these cohorts. In contrast, high expression of PROX1 protein predicted shorter survival in the group of patients with IDH-mutant anaplastic astrocytomas and secondary glioblastomas. The prognostic impact of PROX1 in IDH-mutant 1p19q non-codeleted high-grade astrocytomas, as well as the negative findings in primary glioblastomas, was corroborated by gene expression data extracted from the Cancer Genome Atlas. We conclude that PROX1 is a new prognostic biomarker for 1p19q non-codeleted high-grade astrocytomas that have progressed from pre-existing low-grade tumors and harbor IDH mutations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.11957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341919PMC
November 2016

Improving the Prediction of Prostate Cancer Overall Survival by Supplementing Readily Available Clinical Data with Gene Expression Levels of IGFBP3 and F3 in Formalin-Fixed Paraffin Embedded Core Needle Biopsy Material.

PLoS One 2016 5;11(1):e0145545. Epub 2016 Jan 5.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.

Background: A previously reported expression signature of three genes (IGFBP3, F3 and VGLL3) was shown to have potential prognostic value in estimating overall and cancer-specific survivals at diagnosis of prostate cancer in a pilot cohort study using freshly frozen Fine Needle Aspiration (FNA) samples.

Methods: We carried out a new cohort study with 241 prostate cancer patients diagnosed from 2004-2007 with a follow-up exceeding 6 years in order to verify the prognostic value of gene expression signature in formalin fixed paraffin embedded (FFPE) prostate core needle biopsy tissue samples. The cohort consisted of four patient groups with different survival times and death causes. A four multiplex one-step RT-qPCR test kit, designed and optimized for measuring the expression signature in FFPE core needle biopsy samples, was used. In archive FFPE biopsy samples the expression differences of two genes (IGFBP3 and F3) were measured. The survival time predictions using the current clinical parameters only, such as age at diagnosis, Gleason score, PSA value and tumor stage, and clinical parameters supplemented with the expression levels of IGFBP3 and F3, were compared.

Results: When combined with currently used clinical parameters, the gene expression levels of IGFBP3 and F3 are improving the prediction of survival time as compared to using clinical parameters alone.

Conclusion: The assessment of IGFBP3 and F3 gene expression levels in FFPE prostate cancer tissue would provide an improved survival prediction for prostate cancer patients at the time of diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145545PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4701463PMC
July 2016

NPM1 histone chaperone is upregulated in glioblastoma to promote cell survival and maintain nucleolar shape.

Sci Rep 2015 Nov 12;5:16495. Epub 2015 Nov 12.

Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, CCK R8:05, Karolinska University Hospital in Solna, SE-17176 Stockholm, Sweden.

Glioblastoma (grade IV glioma) is the most common and aggressive adult brain tumor. A better understanding of the biology of glioblastoma cells is crucial to identify molecular targets stimulating cell death. NPM1 (nucleophosmin) is a multifunctional chaperone that plays an important role in cancer development. Herein, NPM1 was analyzed by immunohistochemistry in human astrocytic gliomas. NPM1 was detected in all tumors but with a significantly higher staining intensity in grade IV than in low grade tumors. Depletion of NPM1 had only modest effects on the viability of U251MG, U1242MG, and U343MGa Cl2:6 glioma cells, despite alterations in nucleolar morphology. Glioma cell cultures depleted of NPM1 exposed to micromolar levels of actinomycin D were more prone to cell death (apoptosis) compared to cultures retaining NPM1. We had previously found that NPM1 binds to linker histone H1.5. Here we could show that silencing of H1.5 triggered glioma cell apoptosis as evidenced by a marked increase in both the numbers of cleaved caspase-3(+) cells and in the amounts of cleaved PARP. Enforced expression of NPM1 suppressed apoptosis in H1.5 depleted glioma cells. Although our studies would suggest little effectiveness of targeting NPM1 alone there could be potential using it as a combination treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep16495DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642306PMC
November 2015

Whole Exome- and mRNA-Sequencing of an AT/RT Case Reveals Few Somatic Mutations and Several Deregulated Signalling Pathways in the Context of SMARCB1 Deficiency.

Biomed Res Int 2015 12;2015:862039. Epub 2015 Aug 12.

Department of Oncology-Pathology, Karolinska Institutet, 171 76 Stockholm, Sweden.

Background: AT/RTs are rare aggressive brain tumours, mainly affecting young children. Most cases present with genetic inactivation of SMARCB1, a core member of the SWI/SNF chromatin-remodeling complex. We have performed whole exome- and mRNA-sequencing on an early onset AT/RT case for detection of genetic events potentially contributing to the disease.

Results: A de novo germline variant in SMARCB1, c.601C>T p.Arg201∗, in combination with somatic deletion of the healthy allele is likely the major tumour causing event. Only seven somatic small scale mutations were discovered (hitting SEPT03, H2BFM, ZIC4, HIST2H2AB, ZIK1, KRTAP6-3, and IFNA8). All were found with subclonal allele frequencies (range 5.7-17%) and none were expressed. However, besides SMARCB1, candidate genes affected by predicted damaging germline variants that were expressed were detected (KDM5C, NUMA1, and PCM1). Analysis of differently expressed genes revealed many dysregulated pathways in the tumour, such as cell cycle, CXCR4 pathway, GPCR-signalling, and neuronal system. FGFR1, CXCR4, and MDK were upregulated and may represent possible drug targets.

Conclusion: The loss of SMARCB1 function leads to AT/RT development and deregulated genes and pathways. Additional predisposing events may however contribute. Studies utilizing NGS technologies in larger cohorts will probably identify recurrent genetic and epigenetic alterations and molecular subgroups with implications for clinical practice and development of targeted therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2015/862039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780067PMC
November 2016

mTOR inhibitors blunt the p53 response to nucleolar stress by regulating RPL11 and MDM2 levels.

Cancer Biol Ther 2014 ;15(11):1499-514

a Department of Oncology-Pathology; Karolinska Institutet; Cancer Center Karolinska ; Karolinska University Hospital ; Stockholm , Sweden.

Mechanistic target of rapamycin (mTOR) is a master regulator of cell growth through its ability to stimulate ribosome biogenesis and mRNA translation. In contrast, the p53 tumor suppressor negatively controls cell growth and is activated by a wide range of insults to the cell. The mTOR and p53 signaling pathways are connected by a number of different mechanisms. Chemotherapeutics that inhibit ribosome biogenesis often induce nucleolar stress and activation of p53. Here we have investigated how the p53 response to nucleolar stress is affected by simultaneous mTOR inhibition in osteosarcoma and glioma cell lines. We found that inhibitors of the mTOR pathway including rapamycin, wortmannin, and caffeine blunted the p53 response to nucleolar stress induced by actinomycin D. Synthetic inhibitors of mTOR (temsirolimus, LY294.002 and PP242) also impaired actinomycin D triggered p53 stabilization and induction of p21. Ribosomal protein (RPL11) is known to be required for p53 protein stabilization following nucleolar stress. Treatment of cells with mTOR inhibitors may lead to reduced synthesis of RPL11 and thereby destabilize p53. We found that rapamycin mimicked the effect of RPL11 depletion in terms of blunting the p53 response to nucleolar stress. However, the extent to which the levels of p53 and RPL11 were reduced by rapamycin varied between cell lines. Additional mechanisms whereby rapamycin blunts the p53 response to nucleolar stress are likely to be involved. Indeed, rapamycin increased the levels of endogenous MDM2 despite inhibition of its phosphorylation at Ser-166. Our findings may have implications for the design of combinatorial cancer treatments with mTOR pathway inhibitors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/15384047.2014.955743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4623102PMC
August 2015

Loss of nucleolar histone chaperone NPM1 triggers rearrangement of heterochromatin and synergizes with a deficiency in DNA methyltransferase DNMT3A to drive ribosomal DNA transcription.

J Biol Chem 2014 Dec 27;289(50):34601-19. Epub 2014 Oct 27.

From the Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, Karolinska University Hospital, SE-17176 Stockholm, Sweden

Nucleoli are prominent nuclear structures assembled and organized around actively transcribed ribosomal DNA (rDNA). The nucleolus has emerged as a platform for the organization of chromatin enriched for repressive histone modifications associated with repetitive DNA. NPM1 is a nucleolar protein required for the maintenance of genome stability. However, the role of NPM1 in nucleolar chromatin dynamics and ribosome biogenesis remains unclear. We found that normal fibroblasts and cancer cells depleted of NPM1 displayed deformed nucleoli and a striking rearrangement of perinucleolar heterochromatin, as identified by immunofluorescence staining of trimethylated H3K9, trimethylated H3K27, and heterochromatin protein 1γ (HP1γ/CBX3). By co-immunoprecipitation we found NPM1 associated with HP1γ and core and linker histones. Moreover, NPM1 was required for efficient tethering of HP1γ-enriched chromatin to the nucleolus. We next tested whether the alterations in perinucleolar heterochromatin architecture correlated with a difference in the regulation of rDNA. U1242MG glioma cells depleted of NPM1 presented with altered silver staining of nucleolar organizer regions, coupled to a modest decrease in H3K9 di- and trimethylation at the rDNA promoter. rDNA transcription and cell proliferation were sustained in these cells, indicating that altered organization of heterochromatin was not secondary to inhibition of rDNA transcription. Furthermore, knockdown of DNA methyltransferase DNMT3A markedly enhanced rDNA transcription in NPM1-depleted U1242MG cells. In summary, this study highlights a function of NPM1 in the spatial organization of nucleolus-associated heterochromatin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M114.569244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263867PMC
December 2014

Operator dependent choice of prostate cancer biopsy has limited impact on a gene signature analysis for the highly expressed genes IGFBP3 and F3 in prostate cancer epithelial cells.

PLoS One 2014 8;9(10):e109610. Epub 2014 Oct 8.

Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden; Clinical Oncology, Karolinska University Hospital, Stockholm, Sweden; Chundsell Medicals AB, Stockholm, Sweden.

Background: Predicting the prognosis of prostate cancer disease through gene expression analysis is receiving increasing interest. In many cases, such analyses are based on formalin-fixed, paraffin embedded (FFPE) core needle biopsy material on which Gleason grading for diagnosis has been conducted. Since each patient typically has multiple biopsy samples, and since Gleason grading is an operator dependent procedure known to be difficult, the impact of the operator's choice of biopsy was evaluated.

Methods: Multiple biopsy samples from 43 patients were evaluated using a previously reported gene signature of IGFBP3, F3 and VGLL3 with potential prognostic value in estimating overall survival at diagnosis of prostate cancer. A four multiplex one-step qRT-PCR test kit, designed and optimized for measuring the signature in FFPE core needle biopsy samples was used. Concordance of gene expression levels between primary and secondary Gleason tumor patterns, as well as benign tissue specimens, was analyzed.

Results: The gene expression levels of IGFBP3 and F3 in prostate cancer epithelial cell-containing tissue representing the primary and secondary Gleason patterns were high and consistent, while the low expressed VGLL3 showed more variation in its expression levels.

Conclusion: The assessment of IGFBP3 and F3 gene expression levels in prostate cancer tissue is independent of Gleason patterns, meaning that the impact of operator's choice of biopsy is low.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109610PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4190108PMC
October 2015

Prominin-1 (CD133) defines both stem and non-stem cell populations in CNS development and gliomas.

PLoS One 2014 3;9(9):e106694. Epub 2014 Sep 3.

Center for Molecular Oncologic Pathology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America; Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, United States of America; Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America; Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America.

Prominin-1 (CD133) is a commonly used cancer stem cell marker in central nervous system (CNS) tumors including glioblastoma (GBM). Expression of Prom1 in cancer is thought to parallel expression and function in normal stem cells. Using RNA in situ hybridization and antibody tools capable of detecting multiple isoforms of Prom1, we find evidence for two distinct Prom1 cell populations in mouse brain. Prom1 RNA is first expressed in stem/progenitor cells of the ventricular zone in embryonic brain. Conversely, in adult mouse brain Prom1 RNA is low in SVZ/SGZ stem cell zones but high in a rare but widely distributed cell population (Prom1(hi)). Lineage marker analysis reveals Prom1(hi) cells are Olig2+Sox2+ glia but Olig1/2 knockout mice lacking oligodendroglia retain Prom1(hi) cells. Bromodeoxyuridine labeling identifies Prom1(hi) as slow-dividing distributed progenitors distinct from NG2+Olig2+ oligodendrocyte progenitors. In adult human brain, PROM1 cells are rarely positive for OLIG2, but express astroglial markers GFAP and SOX2. Variability of PROM1 expression levels in human GBM and patient-derived xenografts (PDX) - from no expression to strong, uniform expression--highlights that PROM1 may not always be associated with or restricted to cancer stem cells. TCGA and PDX data show that high expression of PROM1 correlates with poor overall survival. Within proneural subclass tumors, high PROM1 expression correlates inversely with IDH1 (R132H) mutation. These findings support PROM1 as a tumor cell-intrinsic marker related to GBM survival, independent of its stem cell properties, and highlight potentially divergent roles for this protein in normal mouse and human glia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106694PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4153667PMC
May 2015

A study of embryonic stem cell-related proteins in human astrocytomas: identification of Nanog as a predictor of survival.

Int J Cancer 2014 Mar 16;134(5):1123-31. Epub 2013 Sep 16.

Department of Neuroscience, Neurology, Uppsala University, University Hospital, S-751 85, Uppsala; Karolinska Institute, Department of Oncology-Pathology, CCK R8:05, Karolinska University Hospital, S-17176, Stockholm, Sweden.

Recent studies suggest that the regulatory networks controlling the functions of stem cells during development may be abnormally active in human cancers. An embryonic stem cell (ESC) gene signature was found to correlate with a more undifferentiated phenotype of several human cancer types including gliomas, and associated with poor prognosis in breast cancer. In the present study, we used tissue microarrays of 80 low-grade (WHO Grade II) and 98 high-grade human gliomas (WHO Grades III and IV) to investigate the presence of the ESC-related proteins Nanog, Klf4, Oct4, Sox2 and c-Myc by immunohistochemistry. While similar patterns of co-expressed proteins between low- and high-grade gliomas were present, we found up-regulated protein levels of Nanog, Klf4, Oct4 and Sox2 in high-grade gliomas. Survival analysis by Kaplan-Meier analysis revealed a significant shorter survival in the subgroups of low-grade astrocytomas (n = 42) with high levels of Nanog protein (p = 0.0067) and of Klf4 protein (p = 0.0368), in high-grade astrocytomas (n = 85) with high levels of Nanog (p = 0.0042), Klf4 (p = 0.0447), and c-Myc (p = 0.0078) and in glioblastomas only (n = 71) with high levels of Nanog (p = 0.0422) and of c-Myc (p = 0.0256). In the multivariate model, Nanog was identified as an independent prognostic factor in the subgroups of low-grade astrocytomas (p = 0.0039), high-grade astrocytomas (p = 0.0124) and glioblastomas only (p = 0.0544), together with established clinical variables in these tumors. These findings provide further evidence for the joint regulatory pathways of ESC-related proteins in gliomas and identify Nanog as one of the key players in determining clinical outcome of human astrocytomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.28441DOI Listing
March 2014

EpCAM associates with endoplasmic reticulum aminopeptidase 2 (ERAP2) in breast cancer cells.

Biochem Biophys Res Commun 2013 Sep 26;439(2):203-8. Epub 2013 Aug 26.

Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, R8:04 Karolinska University Hospital, Solna, SE-171 76 Stockholm, Sweden. Electronic address:

Epithelial cell adhesion molecule (EpCAM) is an epithelial and cancer cell "marker" and there is a cumulative and growing evidence of its signaling role. Its importance has been recognized as part of the breast cancer stem cell phenotype, the tumorigenic breast cancer stem cell is EpCAM(+). In spite of its complex functions in normal cell development and cancer, relatively little is known about EpCAM-interacting proteins. We used breast cancer cell lines and performed EpCAM co-immunoprecipitation followed by mass spectrometry in search for novel potentially interacting proteins. The endoplasmic reticulum aminopeptidase 2 (ERAP2) was found to co-precipitate with EpCAM and to co-localize in the cytoplasm/ER and the plasma membrane. ERAP2 is a proteolytic enzyme set in the endoplasmic reticulum (ER) where it plays a central role in the trimming of peptides for presentation by MHC class I molecules. Expression of EpCAM and ERAP2 in vitro in the presence of dog pancreas rough microsomes (ER vesicles) confirmed N-linked glycosylation, processing in ER and the size of EpCAM. The association between ERAP2 and EpCAM is a unique and novel finding that provides new ideas on EpCAM processing and on how antigen presentation may be regulated in cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2013.08.059DOI Listing
September 2013

The mitochondrial elongation factors MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics.

Exp Cell Res 2013 Nov 20;319(18):2893-904. Epub 2013 Jul 20.

Department of Oncology-Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden.

Mitochondria are dynamic organelles whose morphology is regulated by a complex balance of fission and fusion processes, and we still know relatively little about how mitochondrial dynamics is regulated. MIEF1 (also called MiD51) has recently been characterized as a key regulator of mitochondrial dynamics and in this report we explore the functions of its paralog MIEF2 (also called MiD49), to learn to what extent MIEF2 is functionally distinct from MIEF1. We show that MIEF1 and MIEF2 have many functions in common. Both are anchored in the mitochondrial outer membrane, recruit Drp1 from the cytoplasm to the mitochondrial surface and cause mitochondrial fusion, and MIEF2, like MIEF1, can interact with Drp1 and hFis1. MIEF1 and MIEF2, however, also differ in certain aspects. MIEF1 and MIEF2 are differentially expressed in human tissues during development. When overexpressed, MIEF2 exerts a stronger fusion-promoting effect than MIEF1, and in line with this, hFis1 and Mff can only partially revert the MIEF2-induced fusion phenotype, whereas MIEF1-induced fusion is reverted to a larger extent by hFis1 and Mff. MIEF2 forms high molecular weight oligomers, while MIEF1 is largely present as a dimer. Furthermore, MIEF1 and MIEF2 use distinct domains for oligomerization: in MIEF1, the region from amino acid residues 109-154 is required, whereas oligomerization of MIEF2 depends on amino acid residues 1 to 49, i.e. the N-terminal end. We also show that oligomerization of MIEF1 is not required for its mitochondrial localization and interaction with Drp1. In conclusion, our data suggest that the mitochondrial regulators MIEF1 and MIEF2 exert partially distinct functions in mitochondrial dynamics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.yexcr.2013.07.010DOI Listing
November 2013

Regulation of mitochondrial dynamics: convergences and divergences between yeast and vertebrates.

Cell Mol Life Sci 2013 Mar 18;70(6):951-76. Epub 2012 Jul 18.

Department of Oncology-Pathology, Karolinska Institutet, CCK R8:05, Karolinska University Hospital Solna, 171 76, Stockholm, Sweden,

In eukaryotic cells, the shape of mitochondria can be tuned to various physiological conditions by a balance of fusion and fission processes termed mitochondrial dynamics. Mitochondrial dynamics controls not only the morphology but also the function of mitochondria, and therefore is crucial in many aspects of a cell's life. Consequently, dysfunction of mitochondrial dynamics has been implicated in a variety of human diseases including cancer. Several proteins important for mitochondrial fusion and fission have been discovered over the past decade. However, there is emerging evidence that there are as yet unidentified proteins important for these processes and that the fusion/fission machinery is not completely conserved between yeast and vertebrates. The recent characterization of several mammalian proteins important for the process that were not conserved in yeast, may indicate that the molecular mechanisms regulating and controlling the morphology and function of mitochondria are more elaborate and complex in vertebrates. This difference could possibly be a consequence of different needs in the different cell types of multicellular organisms. Here, we review recent advances in the field of mitochondrial dynamics. We highlight and discuss the mechanisms regulating recruitment of cytosolic Drp1 to the mitochondrial outer membrane by Fis1, Mff, and MIEF1 in mammals and the divergences in regulation of mitochondrial dynamics between yeast and vertebrates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00018-012-1066-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3578726PMC
March 2013