| 1. |
- Ageberg, Malin, et al.
(författare)
-
Identification of a novel and myeloid specific role of the leukemia-associated fusion protein DEK-NUP214 leading to increased protein synthesis.
- 2008
-
Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 47, s. 276-287
-
Tidskriftsartikel (refereegranskat)abstract
- The t(6;9)(p22;q34) chromosomal translocation is found in a subset of patients with acute myeloid leukemia (AML). The translocation results in a fusion between the nuclear phosphoprotein DEK and the nucleoporin NUP214 (previously CAN). The mechanism by which the fusion protein DEK-NUP214 contributes to leukemia development has not been identified, and disruptions of normal cellular functions by DEK-NUP214 have previously not been described. In the present study, a novel effect of the DEK-NUP214 fusion protein is demonstrated. Our findings reveal a substantial increase in global protein synthesis in DEK-NUP214 expressing cells. Furthermore, we conclude that this effect is not the result of dysregulated transcription but merely due to increased translation. Consistent with the association with AML, the increased protein synthesis mediated by DEK-NUP214 is restricted to cells of the myeloid lineage. Analysis of potential mechanisms for regulating protein synthesis shows that expression of DEK-NUP214 correlates to the phosphorylation of the translation initiation protein, EIF4E. The present data provide evidence that increase of translational activity constitutes a mechanism by which the leukemogenic effect of DEK-NUP124 may be mediated. (c) 2008 Wiley-Liss, Inc.
|
|
| 2. |
- Ageberg, Malin, et al.
(författare)
-
The involvement of cellular proliferation status in the expression of the human proto-oncogene DEK
- 2006
-
Ingår i: Haematologica. - 1592-8721. ; 91:2, s. 268-269
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The role of the DEK protein, involved in the leukemia-associated fusion protein DEK-CAN, is not yet known. In this study, we show a higher expression of DEK mRNA in immature cells than in mature cells. Furthermore, a correlation between DEK expression and cell proliferation was demonstrated, suggesting that DEK plays a role in the proliferation of hematopoietic cells and raising the question of whether the DEK-CAN fusion protein might perturb regulation of proliferation in leukemic cells.
|
|
| 3. |
- Ajore, Ram, et al.
(författare)
-
The leukemia associated ETO nuclear repressor gene is regulated by the GATA-1 transcription factor in erythroid/megakaryocytic cells
- 2010
-
Ingår i: BMC Molecular Biology. - : Springer Science and Business Media LLC. - 1471-2199. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Eight-Twenty-One (ETO) nuclear co-repressor gene belongs to the ETO homologue family also containing Myeloid Translocation Gene on chromosome 16 (MTG16) and myeloid translocation Gene-Related protein 1 (MTGR1). By chromosomal translocations ETO and MTG16 become parts of fusion proteins characteristic of morphological variants of acute myeloid leukemia. Normal functions of ETO homologues have as yet not been examined. The goal of this work was to identify structural and functional promoter elements upstream of the coding sequence of the ETO gene in order to explore lineage-specific hematopoietic expression and get hints to function.RESULTS: A putative proximal ETO promoter was identified within 411 bp upstream of the transcription start site. Strong ETO promoter activity was specifically observed upon transfection of a promoter reporter construct into erythroid/megakaryocytic cells, which have endogeneous ETO gene activity. An evolutionary conserved region of 228 bp revealed potential cis-elements involved in transcription of ETO. Disruption of the evolutionary conserved GATA -636 consensus binding site repressed transactivation and disruption of the ETS1 -705 consensus binding site enhanced activity of the ETO promoter. The promoter was stimulated by overexpression of GATA-1 into erythroid/megakaryocytic cells. Electrophoretic mobility shift assay with erythroid/megakaryocytic cells showed specific binding of GATA-1 to the GATA -636 site. Furthermore, results from chromatin immunoprecipitation showed GATA-1 binding in vivo to the conserved region of the ETO promoter containing the -636 site. The results suggest that the GATA -636 site may have a role in activation of the ETO gene activity in cells with erythroid/megakaryocytic potential. Leukemia associated AML1-ETO strongly suppressed an ETO promoter reporter in erythroid/megakaryocytic cells.CONCLUSIONS: We demonstrate that the GATA-1 transcription factor binds and transactivates the ETO proximal promoter in an erythroid/megakaryocytic-specific manner. Thus, trans-acting factors that are essential in erythroid/megakaryocytic differentiation govern ETO expression.
|
|
| 4. |
- Ajore, Ram, et al.
(författare)
-
The leukemia associated nuclear corepressor ETO homologue genes MTG16 and MTGR1 are regulated differently in hematopoietic cells
- 2012
-
Ingår i: BMC Molecular Biology. - : Springer Science and Business Media LLC. - 1471-2199. ; 13:11
-
Tidskriftsartikel (refereegranskat)abstract
- Background: MTG16, MTGR1 and ETO are nuclear transcriptional corepressors of the human ETO protein family. MTG16 is implicated in hematopoietic development and in controlling erythropoiesis/megakaryopoiesis. Furthermore, ETO homologue genes are 3'participants in leukemia fusions generated by chromosomal translocations responsible of hematopoietic dysregulation. We tried to identify structural and functional promoter elements of MTG16 and MTGR1 genes in order to find associations between their regulation and hematopoiesis. Results: 5' deletion examinations and luciferase reporter gene studies indicated that a 492 bp sequence upstream of the transcription start site is essential for transcriptional activity by the MTG16 promoter. The TATA-and CCAAT-less promoter with a GC box close to the start site showed strong reporter activity when examined in erythroid/megakaryocytic cells. Mutation of an evolutionary conserved GATA -301 consensus binding site repressed promoter function. Furthermore, results from in vitro antibody-enhanced electrophoretic mobility shift assay and in vivo chromatin immunoprecipitation indicated binding of GATA-1 to the GATA -301 site. A role of GATA-1 was also supported by transfection of small interfering RNA, which diminished MTG16 expression. Furthermore, expression of the transcription factor HERP2, which represses GATA-1, produced strong inhibition of the MTG16 promoter reporter consistent with a role of GATA-1 in transcriptional activation. The TATA-less and CCAAT-less MTGR1 promoter retained most of the transcriptional activity within a -308 to -207 bp region with a GC-box-rich sequence containing multiple SP1 binding sites reminiscent of a housekeeping gene with constitutive expression. However, mutations of individual SP1 binding sites did not repress promoter function; multiple active SP1 binding sites may be required to safeguard constitutive MTGR1 transcriptional activity. The observed repression of MTG16/MTGR1 promoters by the leukemia associated AML1-ETO fusion gene may have a role in hematopoietic dysfunction of leukemia. Conclusions: An evolutionary conserved GATA binding site is critical in transcriptional regulation of the MTG16 promoter. In contrast, the MTGR1 gene depends on a GC-box-rich sequence for transcriptional regulation and possible ubiquitous expression. Our results demonstrate that the ETO homologue promoters are regulated differently consistent with hematopoietic cell-type-specific expression and function.
|
|
| 5. |
|
|
| 6. |
- Ali, Mina, et al.
(författare)
-
The multiple myeloma risk allele at 5q15 lowers ELL2 expression and increases ribosomal gene expression
- 2018
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 1649-
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, we identified ELL2 as a susceptibility gene for multiple myeloma (MM). To understand its mechanism of action, we performed expression quantitative trait locus analysis in CD138+ plasma cells from 1630 MM patients from four populations. We show that the MM risk allele lowers ELL2 expression in these cells (Pcombined = 2.5 × 10−27; βcombined = −0.24 SD), but not in peripheral blood or other tissues. Consistent with this, several variants representing the MM risk allele map to regulatory genomic regions, and three yield reduced transcriptional activity in plasmocytoma cell lines. One of these (rs3777189-C) co-locates with the best-supported lead variants for ELL2 expression and MM risk, and reduces binding of MAFF/G/K family transcription factors. Moreover, further analysis reveals that the MM risk allele associates with upregulation of gene sets related to ribosome biogenesis, and knockout/knockdown and rescue experiments in plasmocytoma cell lines support a cause–effect relationship. Our results provide mechanistic insight into MM predisposition.
|
|
| 7. |
- Bergh, Gösta, et al.
(författare)
-
Altered expression of the retinoblastoma tumor-suppressor gene in leukemic cell lines inhibits induction of differentiation but not G1-accumulation
- 1997
-
Ingår i: Blood. - 1528-0020. ; 89:8, s. 2938-2950
-
Tidskriftsartikel (refereegranskat)abstract
- The retinoblastoma tumor-suppressor gene, RB, has been implicated in tumor suppression, in regulation of the cell cycle, and in mediating cell differentiation. RB is necessary for hematopoiesis in mice, and aberrant RB-expression is associated with the progress and prognosis of leukemia. We have used antisense oligonucleotides, established clones stably expressing an antisense RB construct, and also established clones over expressing the retinoblastoma protein (pRb) to study the role of RB expression in monocytic differentiation induced by all-trans retinoic acid (ATRA) or 1-alpha-25-dihyroxycholecalciferol (Vit D3) in the monoblastic cell line U-937 and erythroid differentiation induced by transforming growth factor beta1 (TGFbeta1) and hemin in the erythroleukemic cell line K562. A reduction in pRb production in antisense RB-transfected U-937 clones was shown. Antisense oligonucleotides as well as expression of the antisense RB construct suppressed differentiation responses to ATRA or Vit D3, as judged by the capability to reduce nitro blue tetrazolium, by the appearance of monocyte-related cell surface antigens and by morphologic criteria. K562 cells showed decreased differentiation response to TGFbeta1, but not to hemin, when incubated with antisense oligonucleotides. U-937 antisense RB-transfected cells were also suppressed in their ability to upregulate levels of hypophosphorylated pRb when induced to differentiate. Although U-937 cells incubated with antisense oligonucleotides and clones expressing the antisense RB construct were hampered in their ability to differentiate on incubation with ATRA or Vit D3, the induced G0/G1-accumulation was similar to differentiating control cells treated with ATRA or Vit D3. Intriguingly, U-937 clones overexpressing RB were also inhibited in their differentiation response to ATRA or Vit D3 but not inhibited in their ability to respond with G0/G1 accumulation when induced with these substances. The results indicate that pRb plays a role in induced differentiation of U-937 cells as well as K562 cells involving mechanisms that, at least partially, are distinct from those inducing G1 accumulation.
|
|
| 8. |
- Bergh, Gösta, et al.
(författare)
-
Forced expression of the cyclin-dependent kinase inhibitor p16(INK4A) in leukemic U-937 cells reveals dissociation between cell cycle and differentiation
- 2001
-
Ingår i: Experimental Hematology. - 1873-2399. ; 29:12, s. 1382-1391
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to investigate how the tumor suppressor protein p16(INK4A) interferes with growth and differentiation of leukemic U-937 cells. MATERIALS AND METHODS: U-937 clones constantly overexpressing the cyclin-dependent kinase inhibitor p16(INK4A) were established. Clones transfected with empty vector were used as controls. The effects of high-level expression of p16(INK4A) on proliferation and cell cycle progression were investigated (cell cycle distribution, proliferation rate, analyses of different cell cycle regulatory proteins). The effect of introduction of p16(INK4A) on capacity for induced differentiation, assayed by capacity to reduce nitroblue tetrazolium, was determined. RESULTS: Overexpressed p16(INK4A) protein was active as judged by its ability to bind to CDK-4 in a coimmunoprecipitation assay. Clones overexpressing p16(INK4A) grew slower than controls, without any apparent effects on the phosphorylation status of the retinoblastoma protein (pRb). Instead, p16(INK4A) overexpression affected the phosphorylation status of pRb-related pocket protein p130, which was detected in its growth-restraining hypophosphorylated form. Despite an enhanced tendency to accumulate in G(0)/G(1), p16(INK4A)-overexpressing cells were less sensitive to induction of differentiation with vitamin D(3) or ATRA than control cells. CONCLUSIONS: Constitutive expression of p16(INK4A) in U-937 cells resulted in decreased proliferation as a result of activated p130 rather than pRb. Also, we showed that introduction of p16(INK4A) into U-937 cells impaired their capacity to differentiate. Moreover, the results support the notion that cell differentiation and cell cycle progression are dissociated and independently regulated processes.
|
|
| 9. |
- Biggs, Joseph R., et al.
(författare)
-
The human brm protein is cleaved during apoptosis: the role of cathepsin G
- 2001
-
Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 98:7, s. 3814-3819
-
Tidskriftsartikel (refereegranskat)abstract
- The human brm (hbrm) protein (homologue of the Drosophila melanogaster brahma and Saccharomyces cervisiae SNF-2 proteins) is part of a polypeptide complex believed to regulate chromatin conformation. We have shown that the hbrm protein is cleaved in NB4 leukemic cells after induction of apoptosis by UV-irradiation, DNA damaging agents, or staurosporine. Because hbrm is found only in the nucleus, we have investigated the nature of the proteases that may regulate the degradation of this protein during apoptosis. In an in vitro assay, the hbrm protein could not be cleaved by caspase-3, -7, or -6, the "effector" caspases generally believed to carry out the cleavage of nuclear protein substrates. In contrast, we find that cathepsin G, a granule enzyme found in NB4 cells, cleaves hbrm in a pattern similar to that observed in vivo during apoptosis. In addition, a peptide inhibitor of cathepsin G blocks hbrm cleavage during apoptosis but does not block activation of caspases or cleavage of the nuclear protein polyADP ribose polymerase (PARP). Although localized in granules and in the Golgi complex in untreated cells, cathepsin G becomes diffusely distributed during apoptosis. Cleavage by cathepsin G removes a 20-kDa fragment containing a bromodomain from the carboxyl terminus of hbrm. This cleavage disrupts the association between hbrm and the nuclear matrix; the 160-kDa hbrm cleavage fragment is less tightly associated with the nuclear matrix than full-length hbrm.
|
|
| 10. |
- Bülow, Elinor, et al.
(författare)
-
Sorting for storage in myeloid cells of nonmyeloid proteins and chimeras with the propeptide of myeloperoxidase precursor.
- 2002
-
Ingår i: Journal of Leukocyte Biology. - 1938-3673. ; 71:2, s. 279-288
-
Tidskriftsartikel (refereegranskat)abstract
- During formation of polymorphonuclear neutrophils, proteins are synthesized for storage in granules. Whereas sorting of proteins into distinct subtypes of cytoplasmic granules may reflect the coordinated expression of the proteins contained in them, still the mechanism(s) for the retrieval of proteins from the constitutive secretion is unknown. To investigate the mechanisms of retrieval, nonmyeloid secretory proteins were expressed in myeloid cell lines, and their subcellular fate was assessed. The contribution of the propeptide (MPOpro) of the myeloperoxidase (MPO) precursor was investigated by determining the fate of chimeras containing MPOpro. The nonmyeloid protein alpha(1)-microglobulin (alpha(1)-m) was targeted to storage organelles in 32D cells and colocalized with the lysosomal marker LAMP-1, whereas soluble TNF receptor 1 (sTNFR1) was secreted without granule targeting. Fusion of MPOpro to alpha(1)-m delayed exit from endoplasmic reticulum (ER), but subsequent targeting to dense organelles was indistinguishable from that of alpha(1)-m alone. Fusion proteins between MPOpro and sTNFR1 or green fluorescent protein expressed in myeloid 32D, K562, or PLB-985 cells did not associate stably with calreticulin or calnexin, molecular chaperones that normally interact transiently with the MPO precursor, but were still efficiently retained in the ER followed by degradation. We conclude that normally secreted, nonmyeloid proteins can be targeted efficiently to storage organelles in myeloid cells, that myeloid cells selectively target some proteins for storage but not others, and that MPOpro may contribute to the prolonged ER retention of the MPO precursor independent of the ER-molecular chaperones calreticulin and calnexin.
|
|
| 11. |
- Bülow, Elinor, et al.
(författare)
-
Sorting of neutrophil-specific granule protein human cathelicidin, hCAP-18, when constitutively expressed in myeloid cells.
- 2002
-
Ingår i: Journal of Leukocyte Biology. - 1938-3673. ; 72:1, s. 147-153
-
Tidskriftsartikel (refereegranskat)abstract
- Neutrophil granulocytes carry storage organelles, e.g., azurophil and specific granules. Poorly understood are the mechanisms for retrieval from constitutive secretion followed by sorting for storage. Therefore, we asked whether the specific granule protein human cathelicidin (hCAP-18) could be sorted for storage in other granules when the biosynthetic window is widened to allow this. We observed that hCAP-18 was targeted for storage in lysosome-related organelles when expressed constitutively in the rat basophilic leukemia and the mouse promyelocytic (MPRO) cell lines. In addition, premature release of the antibiotic C-terminal peptide LL-37 was observed. Retention of hCAP-18 was diminished by induction of differentiation of MPRO cells. In conclusion, a specific granule protein with native conformation may be sorted for storage in lysosome-related organelles of myeloid cells and converted prematurely to a supposedly biologically active form.
|
|
| 12. |
- Canny, G, et al.
(författare)
-
Functional and biochemical characterization of epithelial bactericidal/permeability-increasing protein
- 2006
-
Ingår i: American Journal of Physiology: Gastrointestinal and Liver Physiology. - : American Physiological Society. - 1522-1547 .- 0193-1857. ; 290:3, s. 557-567
-
Tidskriftsartikel (refereegranskat)abstract
- Epithelial cells of many mucosal organs have adapted to coexist with microbes and microbial products. In general, most studies suggest that epithelial cells benefit from interactions with commensal microorganisms present at the lumenal surface. However, potentially injurious molecules found in this microenvironment also have the capacity to elicit local inflammatory responses and even systemic disease. We have recently demonstrated that epithelia cells express the anti-infective molecule bactericidal/permeability-increasing protein (BPI). Here, we extend these findings to examine molecular mechanisms of intestinal epithelial cell (IEC) BPI expression and function. Initial experiments revealed a variance of BPI mRNA and protein expression among various IEC lines. Studies of BPI promoter expression in IECs identified regulatory regions of the BPI promoter and revealed a prominent role for CCAAT/enhancer binding protein and especially Sp1/Sp3 in the basal regulation of BPI. To assess the functional significance of this protein, we generated an IEC line stably transfected with full-length BPI. We demonstrated that, whereas epithelia express markedly less BPI protein than neutrophils, epithelial BPI contributes significantly to bacterial killing and attenuating bacterial-elicted proinflammatory signals. Additional studies in murine tissue ex vivo revealed that BPI is diffusely expressed along the crypt-villous axis and that epithelial BPI levels decrease along the length of the intestine. Taken together, these data confirm the transcriptional regulation of BPI in intestinal epithelia and provide insight into the relevance of BPI as an anti-infective molecule at intestinal surfaces.
|
|
| 13. |
- Ceballos, Eva, et al.
(författare)
-
c-Myc antagonizes the effect of p53 on apoptosis and p21WAF1 transactivation in K562 leukemia cells
- 2000
-
Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 0950-9232 .- 1476-5594. ; 19, s. 2194-2204
-
Tidskriftsartikel (refereegranskat)abstract
- c-myc protooncogene positively regulates cell proliferation and overexpression of c-myc is found in many solid tumors and leukemias. In the present study we used the K562 human myeloid leukemia cell line as a model to study the functional interaction between c-Myc and p53. Using two different methods, we generated K562 transfectant cell lines with conditional expression of either c-Myc or p53. The cells expressed the p53Vall35 mutant, which adopts a wild-type conformation at 32 degrees C, while c-Myc induction was achieved with a zinc-inducible expression vector. We found that p53 in wild-type conformation induces growth arrest and apoptosis of K562. Expression of c-Myc significantly attenuated apoptosis and impaired the transcriptional activity of p53 on p21WAF1, Bax and cytomegalovirus promoters. The impairment of p21WAF1 transactivation by c-Myc was confirmed by transfection of a c-Myc-estrogen receptor fusion protein and by induction of c-myc by zinc in transfected cells. Also, p53-mediated up-regulation of p21WAF1 mRNA protein were significantly reduced by c-Myc, while Bax levels were unaffected. Consistently, c-Myc increased cyclin-dependent kinase 2 activity in K562 cells expressing p53 in wild-type conformation. These results suggest that c-Myc overexpression may antagonize the pro-apoptotic function of p53, thus providing a molecular mechanism for the frequently observed deregulation of c-myc in human cancer.
|
|
| 14. |
- Chylicki, Kristina, et al.
(författare)
-
Characterization of the molecular mechanisms for p53-mediated differentiation
- 2000
-
Ingår i: Cell Growth and Differentiation. - 1044-9523. ; 11:11, s. 561-571
-
Tidskriftsartikel (refereegranskat)abstract
- The p53 tumor suppressor protein can induce both apoptosis and cell cycle arrest. Moreover, we and others have shown previously that p53 is a potent mediator of differentiation. For example, expression of ptsp53, a temperature-inducible form of p53, induces differentiation of leukemic monoblastic U-937 cells. The functions of p53 have for long been believed to be dependent on the transactivating capacity of p53. However, recent data show that both p53-induced cell cycle arrest and apoptosis can be induced independently of p53-mediated transcriptional activation, indicating alternative pathways for p53-induced apoptosis and cell cycle arrest. The bcl-2 proto-oncogene contributes to the development of certain malignancies, probably by inhibition of apoptosis. Interestingly, Bcl-2 has been shown to inhibit p53-mediated apoptosis as well as p53-mediated transcriptional activation. Asking whether Bcl-2 would interfere with the p53-mediated differentiation of U-937 cells, we stably transfected bcl-2 to U-937 cells inducibly expressing p53. Although the established Bcl-2-expressing clones were resistant to p53-mediated apoptosis, we did not observe any interference of Bcl-2 with the p53-mediated differentiation, suggesting separable pathways for p53 in mediating apoptosis and differentiation of U-937 cells. Neither did expression of Bcl-2 interfere with p53-induced expression of endogenous p21, suggesting that p53-induced differentiation might be dependent on the transcriptional activity of p53. To further investigate whether the p53-mediated differentiation of U-937 cells depends on the transcriptional activity of p53, we overexpressed transactivation-deficient p53, a transcriptionally inactive p53 mutant in these cells. However, in contrast to the effects of wild-type p53, expression of trans-activation-deficient p53 did neither induce signs of apoptosis nor of differentiation in U-937 cells. Our results indicate that the transcriptional activity of p53 is essential both for p53-mediated apoptosis and differentiation of U-937 cells.
|
|
| 15. |
- Dimberg, Lina Y., et al.
(författare)
-
Stat1 activation attenuates IL-6 induced Stat3 activity but does not alter apoptosis sensitivity in multiple myeloma
- 2012
-
Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 12, s. 318-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Multiple myeloma (MM) is at present an incurable malignancy, characterized by apoptosis-resistant tumor cells. Interferon (IFN) treatment sensitizes MM cells to Fas-induced apoptosis and is associated with an increased activation of Signal transducer and activator of transcription (Stat)1. The role of Stat1 in MM has not been elucidated, but Stat1 has in several studies been ascribed a pro-apoptotic role. Conversely, IL-6 induction of Stat3 is known to confer resistance to apoptosis in MM. Methods: To delineate the role of Stat1 in IFN mediated sensitization to apoptosis, sub-lines of the U-266-1970 MM cell line with a stable expression of the active mutant Stat1C were utilized. The influence of Stat1C constitutive transcriptional activation on endogenous Stat3 expression and activation, and the expression of apoptosis-related genes were analyzed. To determine whether Stat1 alone would be an important determinant in sensitizing MM cells to apoptosis, the U-266-1970-Stat1C cell line and control cells were exposed to high throughput compound screening (HTS). Results: To explore the role of Stat1 in IFN mediated apoptosis sensitization of MM, we established sublines of the MM cell line U-266-1970 constitutively expressing the active mutant Stat1C. We found that constitutive nuclear localization and transcriptional activity of Stat1 was associated with an attenuation of IL-6-induced Stat3 activation and up-regulation of mRNA for the pro-apoptotic Bcl-2 protein family genes Harakiri, the short form of Mcl-1 and Noxa. However, Stat1 activation alone was not sufficient to sensitize cells to Fas-induced apoptosis. In a screening of > 3000 compounds including bortezomib, dexamethasone, etoposide, suberoylanilide hydroxamic acid (SAHA), geldanamycin (17-AAG), doxorubicin and thalidomide, we found that the drug response and IC50 in cells constitutively expressing active Stat1 was mainly unaltered. Conclusion: We conclude that Stat1 alters IL-6 induced Stat3 activity and the expression of pro-apoptotic genes. However, this shift alone is not sufficient to alter apoptosis sensitivity in MM cells, suggesting that Stat1 independent pathways are operative in IFN mediated apoptosis sensitization.
|
|
| 16. |
|
|
| 17. |
- Egesten, Arne, et al.
(författare)
-
Phorbol ester-induced degranulation in adherent human eosinophil granulocytes is dependent on CD11/CD18 leukocyte integrins
- 1993
-
Ingår i: Journal of Leukocyte Biology. - 1938-3673. ; 53:3, s. 93-287
-
Tidskriftsartikel (refereegranskat)abstract
- Secretion of unique eosinophil granule constituents may play a role in allergic and parasitic reactions. Therefore we have investigated possible mechanisms for regulation of secretion in eosinophils. A hemolytic plaque assay and an enzyme-linked immunospot (ELISPOT) assay were developed for detection of secreted eosinophil cationic protein (ECP) from single adherent eosinophils. The protein kinase C activator phorbol 12-myristate 13-acetate (PMA) induced release of ECP in a dose-dependent fashion but 4-alpha-PMA, an analogue that does not activate protein kinase C, did not cause degranulation. Staurosporine and K252a, inhibitors of protein kinase C, decreased PMA-induced ECP secretion. Low concentrations of cytochalasin B enhanced PMA-induced secretion but high concentrations had an inhibitory effect. The calcium ionophores A23187 and ionomycin were weaker secretagogues than PMA. Tumor necrosis factor, granulocyte-macrophage colony-stimulating factor, interleukin-3, interleukin-5, N-formylmethionyl-leucyl-phenylalanine, and lipopolysaccharide caused little or no degranulation in adherent eosinophils. Preincubation of eosinophils with antibodies to CD18, the common beta chain of leukocyte adhesion proteins, resulted in inhibition of PMA-induced ECP release from adherent cells. 1,2-Bis(O-aminophenyl)-ethane-ethane-N,N,N',N'-tetraacetic acid (BAPTA), an agent that acts intracellularly by chelation of calcium, also inhibited PMA-mediated ECP release. In conclusion, PMA induces release of ECP from single adherent eosinophils and the effect appears to be mediated via protein kinase C and, in contrast to that in neutrophils, to be dependent on CD11/CD18 leukocyte integrins.
|
|
| 18. |
- Egesten, Arne, et al.
(författare)
-
The heterogeneity of azurophil granules in neutrophil promyelocytes: immunogold localization of myeloperoxidase, cathepsin G, elastase, proteinase 3, and bactericidal/permeability increasing protein
- 1994
-
Ingår i: Blood. - 1528-0020. ; 83:10, s. 94-2985
-
Tidskriftsartikel (refereegranskat)abstract
- Azurophil granules of myeloid cells form in promyelocytes. They store cytotoxic and digestive agents which when released are involved in the defense against infection. In order to characterize the intragranular distribution of these agents, ultrastructural methods using immunogold were used on promyelocytes. Azurophil granules were divided into nucleated, large spherical (large azurophil) and small electron-dense (small azurophil) granules. Myeloperoxidase showed a peripheral distribution of large azurophils and a uniform distribution of small and nucleated azurophils, consistent with previous findings. Likewise, the major neutral proteases of azurophils, cathepsin G, granulocyte elastase, and proteinase 3, displayed a similar distribution, with a peripheral localization in large azurophils and a uniform distribution in small and nucleated azurophils, except for proteinase 3, which was associated with the crystalloid structure in nucleated azurophils. In contrast, the bactericidal/permeability increasing protein, which is bacteristatic and bactericidal for Gram-negative bacteria, was localized to the membrane area in all types of azurophil granules, consistent with a suggested association of this protein with the granule membrane. The observed differences in intragranular distribution of the proteins investigated may reflect variations in binding to matrix structures and granule membranes.
|
|
| 19. |
- Ehinger, Mats, et al.
(författare)
-
Expression of the p53 tumor suppressor gene induces differentiation and promotes induction of differentiation by 1,25-dihydroxycholecalciferol in leukemic U-937 cells
- 1996
-
Ingår i: Blood. - 1528-0020. ; 87:3, s. 1064-1074
-
Tidskriftsartikel (refereegranskat)abstract
- Leukemic U-937 cells, which lack normal p53, were stably transfected with a temperature-sensitive mutant of p53 to investigate the consequences for growth and differentiation. On induction of wild-type p53 activity at the permissive temperature, some of these cells underwent maturation as judged by the capacity for oxidative burst and the appearance of monocyte related cell surface molecules. Moreover, wild-type p53-expressing cells were more sensitive than p53-negative control cells to induction of differentiation by 1,25-dihydroxycholecalciferol; a twofold to fourfold increase of the fraction of cells showing signs of terminal maturation was observed when wild-type p53-expressing cells were incubated with 1,25-dihydroxycholecalciferol at concentrations that only slightly affected control cells. Whereas wild-type p53 activity per se induced maturation of certain cells, other underwent cell death judging from the reduced capability to exclude trypan blue and the appearance of fragmented DNA in flow cytometric analysis. The p53-induced cell death could be inhibited by incubation with 1,25-dihydroxy-cholecalciferol, but not all-trans retinoic acid. Thus, 1,25-dihydroxycholecalciferol, seemed to increase the survival of wild-type p53-expressing cells and to cooperate with wild-type p53 to induce differentiation. The data imply that p53-mediated maturation in U-937 cells depends on optimal regulation of signals for differentiation, survival and proliferation, and suggest a role for p53 in the differentiation induction of leukemic cells.
|
|
| 20. |
- Ehinger, Mats, et al.
(författare)
-
Involvement of the tumor suppressor gene p53 in tumor necrosis factor-induced differentiation of the leukemic cell line K562
- 1995
-
Ingår i: Cell Growth and Differentiation. - 1044-9523. ; 6:1, s. 9-17
-
Tidskriftsartikel (refereegranskat)abstract
- The cDNA of the human wild-type p53 tumor suppressor gene was constitutively overexpressed in the leukemic cell line K562 (which lacks detectable amounts of p53 protein) in order to investigate the consequences for growth and differentiation. Several stable clones were established by transfection of the expression vector pc53SN3. Expression of p53 protein was characterized by biosynthetic labeling and immunoprecipitation with the monoclonal antibodies pAb 1801 (reacting with wild-type and mutant human p53), pAb 240 (reacting with mutant human p53) and pAb 1620 (reacting with wild-type human p53). All clones which were 1801+, 240-, 1620- or 1801+, 240-, 1620+ were defined as "wild-type-like p53-expressing" clones. Our results show that expression of p53 protein is compatible with continuous proliferation of K562 cells. The growth characteristics of wild-type-like p53-expressing clones did not differ from that of control clones. However, the former were more sensitive than p53-negative control clones to growth inhibition by tumor necrosis factor (TNF), a cytokine with a potential role in growth and differentiation of myeloid leukemic cells. In addition, a 2- to 4-fold increase of the amount of hemoglobin, a marker of erythroid differentiation, was observed when wild-type-like p53 protein-expressing clones were incubated with TNF. This suggests that differentiation is the mechanism responsible for the increased TNF sensitivity of these clones. Our results support a role for p53 in mediating growth inhibitory and differentiation inducing signals by TNF.
|
|
| 21. |
- Eliasson, Pernilla, 1979-
(författare)
-
Live and Let Die : Critical regulation of survival in normal and malignant hematopoietic stem and progenitor cells
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The hematopoietic stem cell (HSC) is characterized by its ability to self-renew and produce all mature blood cells throughout the life of an organism. This is tightly regulated to maintain a balance between survival, proliferation, and differentiation. The HSCs are located in specialized niches in the bone marrow thought to be low in oxygen, which is suggested to be involved in the regulation of HSC maintenance, proliferation, and migration. However, the importance of hypoxia in the stem cell niche and the molecular mechanisms involved remain fairly undefined. Another important regulator of human HSCs maintenance is the tyrosine kinase receptor FLT3, which triggers survival of HSCs and progenitor cells. Mutations in FLT3 cause constitutively active signaling. This leads to uncontrolled survival and proliferation, which can result in development of acute myeloid leukemia (AML). One of the purposes with this thesis is to investigate how survival, proliferation and self-renewal in normal HSCs are affected by hypoxia. To study this, we used both in vitro and in vivo models with isolated Lineage-Sca-1+Kit+ (LSK) and CD34-Flt3-LSK cells from mouse bone marrow. We found that hypoxia maintained an immature phenotype. In addition, hypoxia decreased proliferation and induced cell cycle arrest, which is the signature of HSCs with long term multipotential capacity. A dormant state of HSCs is suggested to be critical for protecting and preventing depletion of the stem cell pool. Furthermore, we observed that hypoxia rescues HSCs from oxidative stress-induced cell death, implicating that hypoxia is important in the bone marrow niche to limit reactive oxidative species (ROS) production and give life-long protection of HSCs. Another focus in this thesis is to investigate downstream pathways involved in tyrosine kinase inhibitor-induced cell death of primary AML cells and cell lines expressing mutated FLT3. Our results demonstrate an important role of the PI3K/AKT pathway to mediate survival signals from FLT3. We found FoxO3a and its target gene Bim to be key players of apoptosis in cells carrying oncogenic FLT3 after treatment with tyrosine kinase inhibitors. In conclusion, this thesis highlights hypoxic-mediated regulation of normal HSCs maintenance and critical effectors of apoptosis in leukemic cells expressing mutated FLT3.
|
|
| 22. |
- Erlanson-Albertsson, Charlotte, et al.
(författare)
-
A burning existence
- 2003
-
Ingår i: Hett om kalla fakta. - 9173070335 ; , s. 133-133
-
Bokkapitel (populärvet., debatt m.m.)
|
|
| 23. |
- Erlanson-Albertsson, Charlotte, et al.
(författare)
-
Cellbiologi
- 2007
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- Boken går igenom de molekyler som bygger upp cellen och hur enzymer arbetar, cellens organeller, cellens olika mekanismer och funktioner. Molekylärbiologiska metoder beskrivs och till sist cellens energimetabolism och reglering av denna. Boken förankrar cellbiologin i verkligheten, dvs. låter läsaren förstå det direkta sambandet mellan synliga symtom hos en patient och de osynliga molekylära händelserna i cellen. Cellbiologi vänder sig till blivande läkare, biomedicinare, tandläkare, biomedicinska analytiker, sjuksköterskor med flera.
|
|
| 24. |
- Frigyesi, Ildiko, et al.
(författare)
-
Robust isolation of malignant plasma cells in multiple myeloma.
- 2014
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 123:9, s. 1336-1340
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular characterization of malignant plasma cells is increasingly important for diagnostic and therapeutic stratification in multiple myeloma (MM). However, the malignant plasma cells represent a relatively small subset of bone marrow cells, and need to be enriched prior to analysis. Currently, the cell surface marker CD138 (SDC1) is used for this enrichment, but has an important limitation in that its expression decreases rapidly after sampling. Seeking alternatives to CD138, we performed a computational screen for myeloma plasma cell markers and evaluated seven candidates systematically. Our results conclusively show that the markers CD319 (SLAMF7/CS1) and CD269 (TNFRSF17/BCMA) are considerably more robust than CD138, and enable isolation of myeloma plasma cells under more diverse conditions, including in samples that have been delayed or frozen. Our results form the basis of improved procedures for characterizing cases of multiple myeloma in clinical practice.
|
|
| 25. |
- Gallwitz, Maike, 1977-
(författare)
-
Sculpted through Time : Evolution and Function of Serine Proteases from the Mast Cell Chymase Locus
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immune cells like NK cells, T cells, neutrophils and mast cells store high amounts of granule serine proteases, graspases. Graspases are encoded from the mast cell chymase locus. The human locus holds four genes: α-chymase, cathepsin G, and granzymes H and B. In contrast, the mouse locus contains at least 14 genes. Many of these belong to subfamilies not found in human, e.g. the Mcpt8-family. These differences hamper functional comparisons of graspases and of immune cells in the two species. Studies of the mast cell chymase locus are therefore important to better understand the mammalian immune system. In this thesis, the evolution of the mast cell chymase locus was analysed by mapping the locus in all available mammalian genome sequences. It was revealed that one single ancestral gene founded this locus probably over 215 million years ago. This ancestor was duplicated more than 185 million years ago. One copy evolved into the α-chymases, whereas the second copy founded the families of granzymes B and H, cathepsin G, Mcpt8 and duodenases. Different subfamilies were later remarkably expanded in particular mammalian lineages, e.g. the Mcpt8- and Mcpt2-subfamilies in the rat. Four novel members of these families were identified in rat mucosal mast cells. Rat and mouse mast cells express numerous different graspases, whereas human and dog mast cells express only one graspase, chymase. To better understand mast cell functions in these species, one member of the mouse Mcpt8-family, mMCP-8, and human and dog chymase were studied. The preferred substrate sequence was analysed by substrate phage display. mMCP-8 remains yet enigmatic, although it is probably proteolytically active. Dog and human chymase, interestingly, have common preferences in certain substrate positions, but differ in others. These two chymases may have coevolved with an in vivo substrate that is conserved only in the positions with a common preference. We also obtained evidence that substrate positions on either side of the scissile bond influence each other. This kind of interactions can only be detected with a method investigating both sides simultaneously, such as substrate phage display.
|
|
