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Fyrberg, Anna
Publications (10 of 15) Show all publications
Fyrberg, A. & Lotfi, K. (2015). NUCLEOSIDE ANALOG ACTIVITY IN MALIGNANT MELANOMA CELL LINES. Nucleosides, Nucleotides & Nucleic Acids, 34(9), 639-649
Open this publication in new window or tab >>NUCLEOSIDE ANALOG ACTIVITY IN MALIGNANT MELANOMA CELL LINES
2015 (English)In: Nucleosides, Nucleotides & Nucleic Acids, ISSN 1525-7770, E-ISSN 1532-2335, Vol. 34, no 9, p. 639-649Article in journal (Refereed) Published
Abstract [en]

Mitochondrial deoxyguanosine kinase (dGK), is an enzyme responsible for activation of nucleoside analogs (NAs) to phosphorylated compounds which exert profound cytotoxicity, especially in hematological malignancies. Screening malignant melanoma cell lines against NAs revealed high sensitivity to several of them. This was believed to be due to the high levels of dGK expression in these cells. Downregulation of dGK in the melanoma cell line RaH5 using siRNA did not cause resistance to NAs as expected, but instead cells became more sensitive. This was probably partly due to the increased activity of another mitochondrial enzyme, thymidine kinase 2, seen in transfected cells.

Place, publisher, year, edition, pages
Taylor andamp; Francis: STM, Behavioural Science and Public Health Titles, 2015
Keywords
Deoxyguanosine kinase; melanoma; leukemia; nucleoside analog; RNAi
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-121095 (URN)10.1080/15257770.2015.1047029 (DOI)000359601400004 ()26252632 (PubMedID)
Note

Funding Agencies|Swedish Cancer Foundation; County Council of Ostergotland; Swedish Medical Society; AFA Insurance; Swedish Fund for Research without Animal Experiments

Available from: 2015-09-07 Created: 2015-09-07 Last updated: 2017-12-04
Jakobsen Falk, I., Fyrberg, A., Paul, E., Nahi, H., Hermanson, M., Rosenquist, R., . . . Lotfi, K. (2014). Impact of ABCB1 single nucleotide polymorphisms 1236C>T and 2677G>T on overall survival in FLT3 wild-type de novo AML patients with normal karyotype. British Journal of Haematology, 167(5), 671-680
Open this publication in new window or tab >>Impact of ABCB1 single nucleotide polymorphisms 1236C>T and 2677G>T on overall survival in FLT3 wild-type de novo AML patients with normal karyotype
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2014 (English)In: British Journal of Haematology, ISSN 0007-1048, E-ISSN 1365-2141, Vol. 167, no 5, p. 671-680Article in journal (Refereed) Published
Abstract [en]

Drug resistance is a clinically relevant problem in the treatment of acute myeloid leukaemia (AML). We have previously reported a relationship between single nucleotide polymorphisms (SNPs) of ABCB1, encoding the multi-drug transporter P-glycoprotein, and overall survival (OS) in normal karyotype (NK)-AML. Here we extended this material, enabling subgroup analysis based on FLT3 and NPM1 status, to further elucidate the influence of ABCB1 SNPs. De novo NK-AML patients (n = 201) were analysed for 1199Ggreater thanA, 1236Cgreater thanT, 2677Ggreater thanT/A and 3435Cgreater thanT, and correlations to outcome were investigated. FLT3 wild-type 1236C/C patients have significantly shorter OS compared to patients carrying the variant allele; medians 20 vs. 49 months, respectively, P = 0.017. There was also an inferior outcome in FLT3 wild-type 2677G/G patients compared to patients carrying the variant allele, median OS 20 vs. 35 months, respectively, P = 0.039. This was confirmed in Cox regression analysis. Our results indicate that ABCB1 1236Cgreater thanT and 2677Ggreater thanT may be used as prognostic markers to distinguish relatively high risk patients in the intermediate risk FLT3 wild-type group, which may contribute to future individualizing of treatment strategies.

Place, publisher, year, edition, pages
Wiley, 2014
Keywords
acute myeloid leukaemia; ABCB1; single nucleotide polymorphism; anthracyclines; FLT3
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-112996 (URN)10.1111/bjh.13097 (DOI)000345222100009 ()25155901 (PubMedID)
Note

Funding Agencies|Swedish Cancer Society; County Council of Ostergotland; AFA Insurance; Stockholm Cancer Society; Karolinska Institutet; Swedish Research Council

Available from: 2015-01-12 Created: 2015-01-08 Last updated: 2019-01-10
Jakobsen Falk, I., Fyrberg, A., Paul, E., Nahi, H., Hermanson, M., Rosenquist, R., . . . Lotfi, K. (2013). Decreased survival in normal karyotype AML with single-nucleotide polymorphisms in genes encoding the AraC metabolizing enzymes cytidine deaminase and 5'-nucleotidase. American Journal of Hematology, 88(12), 1001-1006
Open this publication in new window or tab >>Decreased survival in normal karyotype AML with single-nucleotide polymorphisms in genes encoding the AraC metabolizing enzymes cytidine deaminase and 5'-nucleotidase
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2013 (English)In: American Journal of Hematology, ISSN 0361-8609, E-ISSN 1096-8652, Vol. 88, no 12, p. 1001-1006Article in journal (Refereed) Published
Abstract [en]

De novo acute myeloid leukemia with normal karyotype (NK-AML) comprises a large group of patients with no common cytogenetic alterations and with a large variation in treatment response. Single-nucleotide polymorphisms (SNPs) in genes related to the metabolism of the nucleoside analogue AraC, the backbone in AML treatment, might affect drug sensitivity and treatment outcome. Therefore, SNPs may serve as prognostic biomarkers aiding clinicians in individualized treatment decisions, with the aim of improving patient outcomes. We analyzed polymorphisms in genes encoding cytidine deaminase (CDA 79A>C rs2072671 and −451C>T rs532545), 5′-nucleotidase (cN-II 7A>G rs10883841), and deoxycytidine kinase (DCK 3′UTR 948T>C rs4643786) in 205 de novo NK-AML patients. In FLT3-internal tandem duplication (ITD)-positive patients, the CDA 79C/C and −451T/T genotypes were associated with shorter overall survival compared to other genotypes (5 vs. 24 months, P < 0.001 and 5 vs. 23 months, P = 0.015, respectively), and this was most pronounced in FLT3-ITD-positive/NPM1-positive patients. We observed altered in vitro sensitivity to topoisomerase inhibitory drugs, but not to nucleoside analogues, and a decrease in global DNA methylation in cells carrying both CDA variant alleles. A shorter survival was also observed for the cN-II variant allele, but only in FLT3-ITD-negative patients (25 vs. 31 months, P = 0.075). Our results indicate that polymorphisms in genes related to nucleoside analog drug metabolism may serve as prognostic markers in de novo NK-AML

Place, publisher, year, edition, pages
John Wiley & Sons, 2013
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-98699 (URN)10.1002/ajh.23549 (DOI)000327224000125 ()23873772 (PubMedID)
Available from: 2013-10-11 Created: 2013-10-11 Last updated: 2018-12-19
Fyrberg, A., Skoglund, K., Wolk, M. & Lotfi, K. (2012). A potential role of fetal hemoglobin in the development of multidrug resistance. Biochemical and Biophysical Research Communications - BBRC, 427(3), 456-460
Open this publication in new window or tab >>A potential role of fetal hemoglobin in the development of multidrug resistance
2012 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 427, no 3, p. 456-460Article in journal (Refereed) Published
Abstract [en]

Our previous data from a human leukemic cell line made resistant to the nucleoside analog (NA) 9-beta-D-arabinofuranosylguanine (AraG) revealed a massive upregulation of fetal hemoglobin (HbF) genes and the ABCB1 gene coding for the multidrug resistance P-glycoprotein (P-gp). The expression of these genes is regulated through the same mechanisms, with activation of the p38-MAPK pathway and inhibition of methylation making transcription factors more accessible to activate these genes. We could show that AraG, as well as other NAs, and P-gp substrates could induce global DNA demethylation and induction of Hb gamma and P-gp both at the mRNA and protein expression level. We speculate that the expression of HbF prior to drug exposure or in drug-resistant cell lines is a strategy of the cancer to gain more oxygen, and thereby survival benefits. We also believe that P-gp may be induced in order to excrete Hb degradation products from the cells that would otherwise be toxic. By using Hb gamma siRNA and pharmacological inhibitors of HbF production we here present a possible relationship between HbF induction and multi-drug resistance in a human leukemia cell line model.

Place, publisher, year, edition, pages
Elsevier, 2012
Keywords
Multi-drug resistance, Fetal hemoglobin, Demethylation, Nucleoside analog
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-86656 (URN)10.1016/j.bbrc.2012.07.129 (DOI)000311263200004 ()
Note

Funding Agencies|Swedish Cancer Foundation||County Council of Ostergotland||AFA insurance||

Available from: 2012-12-20 Created: 2012-12-20 Last updated: 2017-12-06
Jakobsen Falk, I. A., Green, K. H., Lotfi, K. & Fyrberg, A. (2012). CORRELATION BETWEEN CYTIDINE DEAMINASE SINGLE NUCLEOTIDE POLYMORPHISMS AND DNA METHYLATION IN ACUTE MYELOGENOUS LEUKEMIA in ANNALS OF ONCOLOGY, vol 23, issue , pp 14-14. In: ANNALS OF ONCOLOGY (pp. 14-14). Oxford University Press (OUP): Policy A1, 23
Open this publication in new window or tab >>CORRELATION BETWEEN CYTIDINE DEAMINASE SINGLE NUCLEOTIDE POLYMORPHISMS AND DNA METHYLATION IN ACUTE MYELOGENOUS LEUKEMIA in ANNALS OF ONCOLOGY, vol 23, issue , pp 14-14
2012 (English)In: ANNALS OF ONCOLOGY, Oxford University Press (OUP): Policy A1 , 2012, Vol. 23, p. 14-14Conference paper, Published paper (Refereed)
Abstract [en]

n/a

Place, publisher, year, edition, pages
Oxford University Press (OUP): Policy A1, 2012
Series
ANNALS OF ONCOLOGY, ISSN 0923-7534
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-79702 (URN)000305825900034 ()
Available from: 2012-08-13 Created: 2012-08-13 Last updated: 2012-08-13
Fyrberg, A., Peterson, C., Kågedal, B. & Lotfi, K. (2011). Induction of fetal hemoglobin and ABCB1 gene expression in 9-β-D-arabinofuranosylguanine-resistant MOLT-4 cells. Cancer Chemotherapy and Pharmacology, 68(3), 583-591
Open this publication in new window or tab >>Induction of fetal hemoglobin and ABCB1 gene expression in 9-β-D-arabinofuranosylguanine-resistant MOLT-4 cells
2011 (English)In: Cancer Chemotherapy and Pharmacology, ISSN 0344-5704, E-ISSN 1432-0843, Vol. 68, no 3, p. 583-591Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To characterize resistance mechanisms to the nucleoside analog 9-β-D-arabinofuranosylguanine (AraG) in the T-cell acute lymphoblastic leukemia cell line MOLT-4 and its AraG-resistant variant.

METHODS: A gene expression microarray analysis was performed, as well as gene expression and enzyme activity measurements of key enzymes in the activation of AraG. Cytotoxicity of AraG and cross-resistance to other compounds were evaluated using a standard cytotoxicity assay.

RESULTS: Gene expression microarray analysis revealed that fetal hemoglobin genes and the multidrug resistance ABCB1 gene, encoding the drug efflux pump P-gp, were the most highly upregulated genes in the resistant cells, while genes traditionally associated with nucleoside analog resistance were not. Fetal hemoglobin and ABCB1 induction can be due to global DNA hypomethylation. This phenomenon was studied using AraG during a period of 4 weeks in MOLT-4 cells and the lung adenocarcinoma cell line A549, leading to up-regulation of hemoglobin gamma and ABCB1 as well as DNA hypomethylation. Inhibiting P-gp in the AraG-resistant MOLT-4 cells led to decreased proliferation, reduced hemoglobin expression, and highly induced ABCB1 expression.

CONCLUSIONS: We show that AraG can cause hypomethylation of DNA and induce the expression of the fetal hemoglobin gamma gene and the ABCB1 gene. We speculate that the induction of ABCB1/P-gp may occur in order to help with excretion of hemoglobin degradation products that would otherwise be toxic to the cells, and we present data supporting our theory that P-gp may be linked to the induction of hemoglobin.

Place, publisher, year, edition, pages
Springer, 2011
Keywords
9-β-D-arabinofuranosylguanine - Fetal hemoglobin - P-glycoprotein - Microarray - Hypomethylation
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-63246 (URN)10.1007/s00280-010-1524-5 (DOI)000294345400004 ()21110023 (PubMedID)
Note
Funding Agencies|Swedish Cancer Foundation||Swedish Childhood Cancer Foundation||Signe and Olof Wallentin Foundation||Capios Research Foundation||County Council of Ostergotland||Swedish Fund for Research without Animal Experiments||Available from: 2010-12-13 Created: 2010-12-13 Last updated: 2017-12-11
Fyrberg, A. (2010). Nucleoside analoge cytotoxicity-focus on enzyme regulation, metabolism, and mechanisms of resistance. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Nucleoside analoge cytotoxicity-focus on enzyme regulation, metabolism, and mechanisms of resistance
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this thesis was to determine the role of nucleoside analog activating and deactivating enzymes in nucleoside analog metabolism and resistance development. Nucleoside analogs are anti-cancer drogs and are often used to treat different leukemias, attributably to presence of high levels of nucleoside analog activating enzymes in hematopoietic cells. More recently some of the newer analogs have been used  successfully to treat solid tumors as well.

We have used human leukemic cell lines, and isolated cells from patients with leukemia, to investigate the nucleoside analog activating enzymes deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK) and some of the deactivating enzymes called 5'nucleotidases (5'-NTs). We have measured mRNA expressions and enzymatic activities and correlated them with the cytotoxic response to nuc1eoside analogs and changes in cell cycle progression. We optimized and evaluated a siRNA-transfection method and decreased the activities of dCK and dGK in two different cell lines in order to find out more about their respective contribution to activation of these drogs. An expression microarray analysis of a nucleoside analog resistant cell line was also performed in order to clarify which genes are involved in development of resistance.

We found that expressions and activities of dCK and dGK were not correlated. The enzyme activities of activating and deactivating enzymes changed during cell cycle progression, giving actively proliferating cells a more favorable enzymatic profile with regard to nucleoside analog cytotoxicity.

The activities of dCK and dGK could be reduced transiently in leukemic and solid tumor cell lines, thereby confer either resistance or increased sensitivity to nucleoside analogs to variable degrees. Expression microarray analysis was used to evaluate the effect of the transfection method and the specificity of siRNA. We concluded that cells tolerated the transfection weIl without major effects on gene expression, and considered the siRNA used to be specific to its target.

An expression microarray experiment on a nucleoside analog-induced resistant cell line revealed a hypomethylating capacity of the drog and induction of fetal hemoglobin and a multidrog resistance efflux pump as a result of the hypomethylation. This pump should not be affected by nucleoside analoges since they are not a substrate of it, and upregulation of the pump unfortunately renders the cells highly cross-resistant to different types of drogs. Our preliminary data supports our theory that it may be upregulated in order to help excrete hemoglobin that otherwise would be toxic to the cells.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2010. p. 72
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1209
National Category
Pharmacology and Toxicology
Identifiers
urn:nbn:se:liu:diva-63247 (URN)978-91-7393-310-0 (ISBN)
Public defence
2010-12-10, Eken, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2011-01-12 Created: 2010-12-13 Last updated: 2018-01-12Bibliographically approved
Fyrberg, A. & Lotfi, K. (2010). Optimization and evaluation of electroporation delivery of siRNA in the human leukemic CEM cell line. CYTOTECHNOLOGY, 62(6), 497-507
Open this publication in new window or tab >>Optimization and evaluation of electroporation delivery of siRNA in the human leukemic CEM cell line
2010 (English)In: CYTOTECHNOLOGY, ISSN 0920-9069, Vol. 62, no 6, p. 497-507Article in journal (Refereed) Published
Abstract [en]

In order to study nucleoside analog activation in the CEM cell line, a transfection protocol had to be optimized in order to silence an enzyme involved in nucleoside analog activation. Hematopoetic cell lines can be difficult to transfect with traditional lipid-based transfection, so the electroporation technique was used. Field strength, pulse length, temperature, electroporation media, siRNA concentration, among other conditions were tested in order to obtain approximately 70-80% mRNA and enzyme activity downregulation of the cytosolic enzyme deoxycytidine kinase (dCK), necessary for nucleoside analog activation. Downregulation was assessed at mRNA and enzyme activity levels. After optimizing the protocol, a microarray analysis was performed in order to investigate whether the downregulation was specific. Additionally two genes were differentially expressed besides the downregulation of dCK. These were however of unknown function. The leakage of intracellular nucleotides was also addressed in the electroporated cells since it can affect the DNA repair mechansism and the efficiency of nucleoside analogs. Three of these pools were increased compared to untreated, unelectroporated cells. The siRNA transfected cells with reduced dCK expression and activity showed reduced sensitivity to several nucleoside analogs as expected. The multidrug resistance to other drugs, as seen in nucleoside analog-induced resistant cells, was not seen with this model.

Place, publisher, year, edition, pages
Springer Science Business Media, 2010
Keywords
RNAi, Electroporation, Microarray, Deoxycytidine kinase, Nucleoside analog
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-63397 (URN)10.1007/s10616-010-9309-6 (DOI)000284844300003 ()
Note
The original publication is available at www.springerlink.com: Anna Fyrberg and Kourosh Lotfi, Optimization and evaluation of electroporation delivery of siRNA in the human leukemic CEM cell line, 2010, CYTOTECHNOLOGY, (62), 6, 497-507. http://dx.doi.org/10.1007/s10616-010-9309-6 Copyright: Springer Science Business Media http://www.springerlink.com/ Available from: 2010-12-17 Created: 2010-12-17 Last updated: 2011-01-13
Fyrberg, A., Albertioni, F. & Lotfi, K. (2008). RNAi Depletion of Deoxycytidine and Deoxyguanosine Kinase in Human Leukemic CEM Cells. Nucleosides, Nucleotides & Nucleic Acids, 27(6-7), 712-719
Open this publication in new window or tab >>RNAi Depletion of Deoxycytidine and Deoxyguanosine Kinase in Human Leukemic CEM Cells
2008 (English)In: Nucleosides, Nucleotides & Nucleic Acids, ISSN 1525-7770, E-ISSN 1532-2335, Vol. 27, no 6-7, p. 712-719Article in journal (Refereed) Published
Abstract [en]

Resistance toward nucleoside analogues is often due to decreased activities of the activating enzymes deoxycytidine kinase (dCK) and/or deoxyguanosine kinase (dGK). With small interfering RNA (siRNA), dCK and dGK were downregulated by approximately 70% in CEM cells and tested against six nucleoside analogues using the methyl thiazol tetrazolium assay. SiRNA-transfected cells reduced in dCK activity were 3- to 6-fold less sensitive to CdA, AraC, and CAFdA. The sensitivity to AraG and FaraA was unchanged, while the sensitivity toward gemcitabine was significantly increased. dGK depletion in cells resulted in lower sensitivity to FaraA, dFdC, CAFdA, and AraG, but slightly higher sensitivity to CdA and AraC.

Keywords
deoxycytidine kinase, deoxyguanosine kinase, nucleoside analogue, resistance, RNA interference
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-45875 (URN)10.1080/15257770802145231 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13Bibliographically approved
Engström, L., Rosén, K., Angel, A., Fyrberg, A., Mackerlova, L., Konsman, J. P., . . . Blomqvist, A. (2008). Systemic immune challenge activates an intrinsically regulated local inflammatory circuit in the adrenal gland. Endocrinology, 149(4), 1436-1450
Open this publication in new window or tab >>Systemic immune challenge activates an intrinsically regulated local inflammatory circuit in the adrenal gland
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2008 (English)In: Endocrinology, ISSN 0013-7227, E-ISSN 1945-7170, Vol. 149, no 4, p. 1436-1450Article in journal (Refereed) Published
Abstract [en]

There is evidence from in vitro studies that inflammatory messengers influence the release of stress hormone via direct effects on the adrenal gland; however, the mechanisms underlying these effects in the intact organism are unknown. Here we demonstrate that systemic inflammation in rats elicited by iv injection of lipopolysaccharide results in dynamic changes in the adrenal immune cell population, implying a rapid depletion of dendritic cells in the inner cortical layer and the recruitment of immature cells to the outer layers. These changes are accompanied by an induced production of IL-1β and IL-1 receptor type 1 as well as cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in these cells, implying local cytokine-mediated prostaglandin E2 production in the adrenals, which also displayed prostaglandin E2 receptors of subtypes 1 and 3 in the cortex and medulla. The IL-1β expression was also induced by systemically administrated IL-1β and was in both cases attenuated by IL-1 receptor antagonist, consistent with an autocrine signaling loop. IL-1β similarly induced expression of cyclooxygenase-2, but the cyclooxygenase-2 expression was, in contrast, further enhanced by IL-1 receptor antagonist. These data demonstrate a mechanism by which systemic inflammatory agents activate an intrinsically regulated local signaling circuit that may influence the adrenals’ response to immune stress and may help explain the dissociation between plasma levels of ACTH and corticosteroids during chronic immune perturbations.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-12958 (URN)10.1210/en.2007-1456 (DOI)
Available from: 2008-02-25 Created: 2008-02-25 Last updated: 2017-12-13
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