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Hellman, Ulf
Alternative names
Publications (10 of 76) Show all publications
Chen, Z. X., Wallis, K., Fell, S. M., Sobrado, V. R., Hemmer, M. C., Ramsköld, D., . . . Schlisio, S. (2014). RNA helicase A is a downstream mediator of KIF1Bβ tumor-suppressor function in neuroblastoma. Cancer Discovery, 4(4), 434-451.
Open this publication in new window or tab >>RNA helicase A is a downstream mediator of KIF1Bβ tumor-suppressor function in neuroblastoma
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2014 (English)In: Cancer Discovery, ISSN 2159-8274, E-ISSN 2159-8290, Vol. 4, no 4, 434-451 p.Article in journal (Refereed) Published
Abstract [en]

UNLABELLED: Inherited KIF1B loss-of-function mutations in neuroblastomas and pheochromocytomas implicate the kinesin KIF1B as a 1p36.2 tumor suppressor. However, the mechanism of tumor suppression is unknown. We found that KIF1B isoform β (KIF1Bβ) interacts with RNA helicase A (DHX9), causing nuclear accumulation of DHX9, followed by subsequent induction of the proapoptotic XIAP-associated factor 1 (XAF1) and, consequently, apoptosis. Pheochromocytoma and neuroblastoma arise from neural crest progenitors that compete for growth factors such as nerve growth factor (NGF) during development. KIF1Bβ is required for developmental apoptosis induced by competition for NGF. We show that DHX9 is induced by and required for apoptosis stimulated by NGF deprivation. Moreover, neuroblastomas with chromosomal deletion of 1p36 exhibit loss of KIF1Bβ expression and impaired DHX9 nuclear localization, implicating the loss of DHX9 nuclear activity in neuroblastoma pathogenesis.

SIGNIFICANCE: KIF1Bβ has neuroblastoma tumor-suppressor properties and promotes and requires nuclear-localized DHX9 for its apoptotic function by activating XAF1 expression. Loss of KIF1Bβ alters subcellular localization of DHX9 and diminishes NGF dependence of sympathetic neurons, leading to reduced culling of neural progenitors, and, therefore, might predispose to tumor formation.

National Category
Cancer and Oncology
Identifiers
urn:nbn:se:uu:diva-231916 (URN)10.1158/2159-8290.CD-13-0362 (DOI)000334347300024 ()24469107 (PubMedID)
Funder
Swedish Childhood Cancer FoundationThe Swedish Brain FoundationSwedish Research CouncilSwedish Cancer SocietyÅke Wiberg Foundation
Available from: 2014-09-11 Created: 2014-09-11 Last updated: 2017-12-05Bibliographically approved
Gemoll, T., Habermann, J. K., Lahmann, J., Szymczak, S., Lundgren, C., Bündgen, N. K., . . . Jörnvall, H. (2012). Protein profiling of genomic instability in endometrial cancer. Cellular and Molecular Life Sciences (CMLS), 69(2), 325-333.
Open this publication in new window or tab >>Protein profiling of genomic instability in endometrial cancer
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2012 (English)In: Cellular and Molecular Life Sciences (CMLS), ISSN 1420-682X, E-ISSN 1420-9071, Vol. 69, no 2, 325-333 p.Article in journal (Refereed) Published
Abstract [en]

DNA aneuploidy has been identified as a prognostic factor in the majority of epithelial malignancies. We aimed at identifying ploidy-associated protein expression in endometrial cancer of different prognostic subgroups. Comparison of gel electrophoresis-based protein expression patterns between normal endometrium (n = 5), diploid (n = 7), and aneuploid (n = 7) endometrial carcinoma detected 121 ploidy-associated protein forms, 42 differentially expressed between normal endometrium and diploid endometrioid carcinomas, 37 between diploid and aneuploid endometrioid carcinomas, and 41 between diploid endometrioid and aneuploid uterine papillary serous cancer. Proteins were identified by mass spectrometry and evaluated by Ingenuity Pathway Analysis. Targets were confirmed by liquid chromatography/mass spectrometry. Mass spectrometry identified 41 distinct polypeptides and pathway analysis resulted in high-ranked networks with vimentin and Nf-kappa B as central nodes. These results identify ploidy-associated protein expression differences that overrule histopathology-associated expression differences and emphasize particular protein networks in genomic stability of endometrial cancer.

Place, publisher, year, edition, pages
Springer, 2012
Keyword
Aneuploidy, Endometrial carcinoma, Genomic instability, Mass spectrometry, Pathway analysis, Two-dimensional gel electrophoresis
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-168100 (URN)10.1007/s00018-011-0752-0 (DOI)000298653500011 ()
Available from: 2012-02-07 Created: 2012-02-06 Last updated: 2017-12-08Bibliographically approved
Feliziani, C., Merino, M. C., Rivero, M. R., Hellman, U., Pistoresi-Palencia, M. C. & Rópolo, A. S. (2011). Immunodominant proteins α-1 giardin and β-giardin are expressed in both assemblages A and B of Giardia lamblia. BMC Microbiology, 11, 233.
Open this publication in new window or tab >>Immunodominant proteins α-1 giardin and β-giardin are expressed in both assemblages A and B of Giardia lamblia
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2011 (English)In: BMC Microbiology, ISSN 1471-2180, E-ISSN 1471-2180, Vol. 11, 233- p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: To date, eight assemblages of Giardia lamblia have been described, but only assemblages A and B are known to infect humans. Despite the fact that the genomic, biological, and clinical differences found between these two assemblages has raised the possibility that they may be considered different species, there is relatively limited information on their phenotypic differences. In the present study, we developed monoclonal antibodies against alpha-1 and beta giardin, two immunodominant proteins produced during G. lamblia infection, and studied their expression and localization in WB (assemblage A) and GS trophozoites (assemblage B).

RESULTS: The polyclonal antibodies generated against WB trophozoites, particularly those recognizing intracellular proteins as well as the proteins present at the plasma membrane (variable-specific surface proteins), showed cross-reactivity with intracellular proteins in GS trophozoites. The use of monoclonal antibodies against beta giardin indicated ventral disc localization, particularly at the periphery in WB trophozoites. Interestingly, although beta giardin was also restricted to the ventral disc in GS trophozoites, the pattern of localization clearly differed in this assemblage. On the other hand, monoclonal antibodies against alpha-1 giardin showed plasma membrane localization in both assemblages with the bare area of GS trophozoites also being distinguished. Moreover, the same localization at the plasma membrane was observed in Portland-1 (Assemblage A) and in P15 (Assemblage E) trophozoites.

CONCLUSIONS: We found differences in localization of the beta giardin protein between assemblages A and B, but the same pattern of localization of alpha-1 giardin in strains from Assemblages A, B and E. These findings reinforce the need for more studies based on phenotypic characteristics in order to disclose how far one assemblage is from the other.

Keyword
mathematical model, Smad, TGF-beta, ultrasensitivity
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-161166 (URN)10.1186/1471-2180-11-233 (DOI)000296636600001 ()22011206 (PubMedID)
Available from: 2011-11-08 Created: 2011-11-08 Last updated: 2017-12-08Bibliographically approved
Bhaskaran, N., Lin, K. W., Gautier, A., Woksepp, H., Hellman, U. & Souchelnytskyi, S. (2009). Comparative proteome profiling of MCF10A and 184A1 human breast epithelial cells emphasized involvement of CDK4 and cyclin D3 in cell proliferation. Proteomics Clinical Applications, 3(1), 68-77.
Open this publication in new window or tab >>Comparative proteome profiling of MCF10A and 184A1 human breast epithelial cells emphasized involvement of CDK4 and cyclin D3 in cell proliferation
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2009 (English)In: Proteomics Clinical Applications, ISSN 1862-8354, Vol. 3, no 1, 68-77 p.Article in journal (Refereed) Published
Abstract [en]

Acquiring high proliferation rate is crucial for carcinogenic transformation of cells. We reporthere proteome profiling of human breast epithelial cells with low (184A1) and high (MCF10A)proliferation rates.We identified 183 proteins in 184A1 and 318 proteins in MCF10A cells. Thesedatasets provide the most comprehensive proteome annotations of 184A1 and MCF10A cells.Proteins were taken for identification from 2-D gels in a systematic and unbiased way. Functionalclustering of the identified proteins showed similarities in distribution of proteins to the samefunctional domains, indicating similarities in proteomes of 184A1 and MCF10A cells. Amongobserved differences in protein expression, we validated correlation of expression of endogenouscyclin-dependent kinase 4 (CDK4), cyclin D3, cdc25B, and p38g with cell proliferation. Furthermore,down-regulation of CDK4 and cyclin D3 with specific siRNA inhibited cell proliferation,which emphasized the role of CDK4 and cyclin D3 in enhancement of cell proliferation rate ofhuman breast epithelial cells.

Keyword
Breast epithelial cells, CDK4, Cyclin D3, Proliferation, Proteome profiling
National Category
Cancer and Oncology Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-106888 (URN)10.1002/prca.200800045 (DOI)000262893600008 ()
Available from: 2009-07-09 Created: 2009-07-09 Last updated: 2010-12-14Bibliographically approved
Bilyy, R., Kit, Y., Hellman, U. & Stoika, R. (2008). AMID: new insights on its intracellular localization and expression at apoptosis. Apoptosis (London), 13(5), 729-732.
Open this publication in new window or tab >>AMID: new insights on its intracellular localization and expression at apoptosis
2008 (English)In: Apoptosis (London), ISSN 1360-8185, E-ISSN 1573-675X, Vol. 13, no 5, 729-732 p.Article in journal (Refereed) Published
Abstract [en]

AMID (apoptosis-inducing factor (AIF)-like mitochondrion-associated inducer of death) is a poorly studied member of the AIF family; despite the given name AMID, predicting its association with mitochondria, its real cellular localization, as well as its role and changes during apoptosis are currently unclear. By means of MALDI-TOF mass spectrometry, we have identified as AMID (accession number AAH38129, sequence coverage 31%) the protein isolated by Pisum sativum lectin-affinity chromatography from the plasma membrane fraction of apoptotic murine leukemia L1210 cells, lacking in the intact cells. The obtained results suggest its possible glycosylation that was further suggested by finding N-glycosylation sequon in the signal peptide of AMID protein (in silica), and by predicting transmembrane localization of its N-terminal part. Using monoclonal antibodies to AMID, we demonstrated an increased expression of AMID in human leukemia Jurkat T-cells after apoptosis induction. Immunocytochemical study suggested its association to the plasma membrane.

Keyword
AMID, AIF, Apoptosis, Plasma membrane, Glycosylation, Lectin, MALDI-TOF MS
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-16086 (URN)10.1007/s10495-008-0198-5 (DOI)000255030400012 ()18368494 (PubMedID)
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-08Bibliographically approved
Cabrera, G., Cabrejos, M. E., Morassutti, A. L., Cabezón, C., Orellana, J., Hellman, U., . . . Galanti, N. (2008). DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts. Journal of Cellular Physiology, 216(2), 498-506.
Open this publication in new window or tab >>DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts
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2008 (English)In: Journal of Cellular Physiology, ISSN 0021-9541, E-ISSN 1097-4652, Vol. 216, no 2, 498-506 p.Article in journal (Refereed) Published
Abstract [en]

Hydatidosis, caused by the larval stage of the platyhelminth parasite Echinococcus granulosus, affects human and animal health. Hydatid fertile cysts are formed in intermediate hosts (human and herbivores) producing protoscoleces, the infective form to canines, at their germinal layers. Infertile cysts are also formed, but they are unable to produce protoscoleces. The molecular mechanisms involved in hydatid cysts fertility/infertility are unknown. Nevertheless, previous work from our laboratory has suggested that apoptosis is involved in hydatid cyst infertility and death. On the other hand, fertile hydatid cysts can resist oxidative damage due to reactive oxygen and nitrogen species. On these foundations, we have postulated that when oxidative damage of DNA in the germinal layers exceeds the capability of DNA repair mechanisms, apoptosis is triggered and hydatid cysts infertility occurs. We describe a much higher percentage of nuclei with oxidative DNA damage in dead protoscoleces and in the germinal layer of infertile cysts than in fertile cysts, suggesting that DNA repair mechanisms are active in fertile cysts. rad9, a conserved gene, plays a key role in cell cycle checkpoint modulation and DNA repair. We found that RAD9 of E. granulosus (EgRAD9) is expressed at the mRNA and protein levels. As it was found in other eukaryotes, EgRAD9 is hyperphosphorylated in response to DNA damage. Our results suggest that molecules involved in DNA repair in the germinal layer of fertile hydatid cysts and in protoscoleces, such as EgRAD9, may allow preserving the fertility of hydatid cysts in the presence of ROS and RNS.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-17588 (URN)10.1002/jcp.21418 (DOI)000257352500027 ()18348165 (PubMedID)
Available from: 2008-07-10 Created: 2008-07-10 Last updated: 2017-12-08Bibliographically approved
Bardales, J. R., Hellman, U. & Villamarín, J. A. (2008). Identification of multiple isoforms of the cAMP-dependent protein kinase catalytic subunit in the bivalve mollusc Mytilus galloprovincialis. The FEBS Journal, 275(18), 4479-4489.
Open this publication in new window or tab >>Identification of multiple isoforms of the cAMP-dependent protein kinase catalytic subunit in the bivalve mollusc Mytilus galloprovincialis
2008 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 275, no 18, 4479-4489 p.Article in journal (Refereed) Published
Abstract [en]

Several isoforms of the cAMP-dependent protein kinase catalytic subunit (C-subunit) were separated from the posterior adductor muscle and the mantle tissues of the sea mussel Mytilus galloprovincialis by cation exchange chromatography, and identified by: (a) protein kinase activity; (b) antibody recognition; and (c) peptide mass fingerprinting. Some of the isozymes seemed to be tissue-specific, and all them were phosphorylated at serine and threonine residues and showed slight but significant differences in their apparent molecular mass values, which ranged from 41.3 to 44.5 kDa. The results from the MS analysis suggest that at least some of the mussel C-subunit isoforms arise as a result of alternative splicing events. Furthermore, several peptide sequences from mussel C-subunits, determined by de novo sequencing, showed a high degree of homology with the mammalian Calpha-isoform, and contained some structural motifs that are essential for catalytic function. On the other hand, no significant differences were observed in the kinetic parameters of C-subunit isoforms, determined by using synthetic peptides as substrate and inhibitor. However, the C-subunit isoforms separated from the mantle tissue differed in their ability to phosphorylate in vitro some proteins present in a mantle extract.

Keyword
cAMP-dependent protein kinase, catalytic subunit, C-subunit isoforms, MALDI-TOF⁄ TOF MS, Mytilus
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-85619 (URN)10.1111/j.1742-4658.2008.06591.x (DOI)000258729100006 ()18671732 (PubMedID)
Available from: 2008-10-23 Created: 2008-10-23 Last updated: 2017-12-14Bibliographically approved
Conrotto, P. & Hellman, U. (2008). Lys Tag: an easy and robust chemical modification for improved de novo sequencing with a matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometer. Rapid Communications in Mass Spectrometry, 22(12), 1823-33.
Open this publication in new window or tab >>Lys Tag: an easy and robust chemical modification for improved de novo sequencing with a matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometer
2008 (English)In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 22, no 12, 1823-33 p.Article in journal (Refereed) Published
Abstract [en]

Mass spectrometry using a matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) instrument is a widespread technique for various types of proteomic analysis. Along with an expanding interest in proteomics, there is a strong requirement for the identification of proteins with high confidence from biological samples. Peptide modification by a wide variety of post-translational modifications (PTMs), the existence of different protein isoforms and the presence of uncharacterized genomes of many species, make protein identification through peptide mass fingerprinting (PMF) often unachievable. Peptide de novo sequencing has been proven to be a useful approach to overcome these variables, and efficient derivatization processes are important tools to achieve this goal. In the present work we describe the methodology and experimental applications of a fast, efficient and cheap lysine derivatization. This chemical modification improves the signals from lysine-terminated peptides and can be efficiently used as a lysine-blocking agent in combination with other derivatization techniques. Most importantly, upon peptide fragmentation it generates a neat series of predominantly y-ions, allowing the determination of unambiguous amino acid sequences. Moreover, this chemical compound was used with target-eluted samples, enabling a second, alternative analysis of the same sample in the MALDI mass spectrometer.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-17572 (URN)10.1002/rcm.3555 (DOI)000256985100008 ()18470875 (PubMedID)
Available from: 2008-07-10 Created: 2008-07-10 Last updated: 2017-12-08Bibliographically approved
Hegazy, U. M., Tars, K., Hellman, U. & Mannervik, B. (2008). Modulating Catalytic Activity by Unnatural Amino Acid Residues in a GSH-Binding Loop of GST P1-1. Journal of Molecular Biology, 376(3), 811-826.
Open this publication in new window or tab >>Modulating Catalytic Activity by Unnatural Amino Acid Residues in a GSH-Binding Loop of GST P1-1
2008 (English)In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 376, no 3, 811-826 p.Article in journal (Refereed) Published
Abstract [en]

The loop following helix alpha2 in glutathione transferase P1-1 has two conserved residues, Cys48 and Tyr50, important for glutathione (GSH) binding and catalytic activity. Chemical modification of Cys48 thwarts the catalytic activity of the enzyme, and mutation of Tyr50 generally decreases the k(cat) value and the affinity for GSH in a differential manner. Cys48 and Tyr50 were targeted by site-specific mutations and chemical modifications in order to investigate how the alpha2 loop modulates GSH binding and catalysis. Mutation of Cys48 into Ala increased K(M)(GSH) 24-fold and decreased the binding energy of GSH by 1.5 kcal/mol. Furthermore, the protein stability against thermal inactivation and chemical denaturation decreased. The crystal structure of the Cys-free variant was determined, and its similarity to the wild-type structure suggests that the mutation of Cys48 increases the flexibility of the alpha2 loop rather than dislocating the GSH-interacting residues. On the other hand, replacement of Tyr50 with Cys, producing mutant Y50C, increased the Gibbs free energy of the catalyzed reaction by 4.8 kcal/mol, lowered the affinity for S-hexyl glutathione by 2.2 kcal/mol, and decreased the thermal stability. The targeted alkylation of Cys50 in Y50C increased the affinity for GSH and protein stability. Characterization of the most active alkylated variants, S-n-butyl-, S-n-pentyl-, and S-cyclobutylmethyl-Y50C, indicated that the affinity for GSH is restored by stabilizing the alpha2 loop through positioning of the key residue into the lock structure of the neighboring subunit. In addition, k(cat) can be further modulated by varying the structure of the key residue side chain, which impinges on the rate-limiting step of catalysis.

Keyword
human glutathione transferase P1-1; site-specific chemical modification; GSH binding; activation energy; GST P1-1 mutant structure
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-12876 (URN)10.1016/j.jmb.2007.12.013 (DOI)000253354900018 ()18177897 (PubMedID)
Available from: 2008-01-18 Created: 2008-01-18 Last updated: 2017-12-11Bibliographically approved
Yin, B. W., Kiyamova, R., Chua, R., Caballero, O. L., Gout, I., Gryshkova, V., . . . Ritter, G. (2008). Monoclonal antibody MX35 detects the membrane transporter NaPi2b (SLC34A2) in human carcinomas. Cancer Immunity, 8, 3.
Open this publication in new window or tab >>Monoclonal antibody MX35 detects the membrane transporter NaPi2b (SLC34A2) in human carcinomas
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2008 (English)In: Cancer Immunity, ISSN 1424-9634, E-ISSN 1424-9634, Vol. 8, 3- p.Article in journal (Refereed) Published
Abstract [en]

Mouse monoclonal antibody MX35 was developed against ovarian cancer. The antibody showed homogeneous reactivity with approximately 90% of human ovarian epithelial cancers and with a limited number of normal tissues by immunohistochemistry. Although mAb MX35 has been used in a number of clinical trials in ovarian cancer, it has been difficult to define the molecular identity of MX35. We report here that mAb MX35 recognizes the sodium-dependent phosphate transport protein 2b (NaPi2b) in human cancer cells. This conclusion is based on several lines of experimental evidence, including 1) the identification of SLC34A2, the gene coding for NaPi2b, by immunoscreening an ovarian cancer cell line cDNA expression library with mAb MX35; 2) mass spectrometry sequencing of peptides obtained by fragmentation from mAb MX35 affinity-purified antigen, which show complete sequence homology to amino acid sequences in NaPi2b; 3) selective down-regulation of SLC34A2 gene expression by RNA interference and the resulting loss of mAb MX35 binding to MX35-expressing human cancer cells; and 4) the demonstration of specific mAb MX35 reactivity with recombinant fusion proteins and with synthetic peptides of the putative largest extracellular loop of NaPi2b. We further show that NaPi2b in cancer cells is expressed on the cell surface as a heavily N-glycosylated protein, with evidence of additional post-translational modifications such as palmitoylation and the formation of disulfide bridges in the major extracellular loop. Membrane transporter molecules, such as NaPi2b, represent a new family of potential cell surface targets for the immunotherapy of cancer with monoclonal antibodies.

Keyword
ovarian cancer, monoclonal antibody, MX35, protein sequence analysis, NaPi2b, tumor antigen, cancer immunotherapy
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-15933 (URN)18251464 (PubMedID)
Available from: 2008-03-19 Created: 2008-03-19 Last updated: 2017-12-08Bibliographically approved
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