scholarly journals The influence of fullerenol on the cell number, cell area and colony forming unit ability in irradiated human erythroleukemic cell line

2007 ◽  
Vol 61 (3) ◽  
pp. 167-170 ◽  
Author(s):  
Ivana Icevic ◽  
Visnja Bogdanovic ◽  
Dragan Zikic ◽  
Slavica Solajic ◽  
Gordana Bogdanovic ◽  
...  
Keyword(s):  
Colony Formation ◽  
K562 Cells ◽  
Cell Number ◽  
Cell Area ◽  
X Rays ◽  
Colony Forming Unit ◽  
Erythroleukemic Cell ◽  
Analysis Of The Images ◽  
Erythroleukemic Cell Line ◽  
Cell Colony

DET (dye exclusion test) cell count and cell area by computer analysis of the images were determined in cell lines of human eritroleukemia (K562), which were irradiated with X-rays in one dose of 24 Gy and pretreated with 10 nmol/mL fullerenol (Cgo(OH)24). Cell samples obtained using a citocentrifuge and May-Gr?nvald Giemsi (MGG) during, were analyzed. The cell colony formation ability was monitored using quantative CFU (colony forming unit) test. Irradiation decreases the number of K562 cells, but fullerenol significantly increases cell number on 24th and 48th hour of the experiment. Cell area is larger, and the number of formed cell colonies after irradiation is significantly smaller compared to pretreated groups during the whole experiment. Pretreatment with fullerenol maintains a smaller cell area, and the number of colony formed units was larger compared to the irradiated cells.

scholarly journals Expression and modulation of specific, high affinity binding sites for erythropoietin on the human erythroleukemic cell line K562

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 104-109 ◽  
Author(s):  
JK Fraser ◽  
FK Lin ◽  
MV Berridge
Keyword(s):  
Cell Line ◽  
K562 Cell ◽  
K562 Cells ◽  
Erythroid Differentiation ◽  
Receptor Expression ◽  
Target Cells ◽  
Epo Receptor ◽  
High Affinity ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line

Erythroid differentiation is mediated by several interacting factors which include the glycoprotein hormone erythropoietin (Epo), interleukin-3 (IL-3) in the mouse, and erythroid-potentiating activity (EPA) in humans. Each of these factors binds to specific cell surface receptors on responsive target cells, but the way in which these factors interact to modulate erythropoiesis is unknown. In the present study, we used the human erythroleukemic cell line K562 to examine expression and regulation of the receptor for Epo using 125I-labeled, bioactive recombinant human Epo. K562 cells expressed low numbers of a single class of high-affinity Epo receptors corresponding to 4 to 6 receptors per K562 cell (KD = 270 to 290 pmol/L). Treatment of K562 cell cultures with medium conditioned by the EPA-secreting cell line U937 (U937CM) increased receptor expression 2.6 to 3.5-fold to 13 to 17 receptors/cell (KD = 260 to 300 pmol/L). That all of the Epo receptor- potentiating activity in U937CM was accounted for by EPA was shown by a similar increase in Epo receptor expression on K562 cells with recombinant EPA. The effect of U937CM on Epo receptors was reversed by culturing cells in inducer-free medium for 3 days. Medium conditioned by the 5637 cell line had no effect on Epo receptors on K562 cells. In methylcellulose culture, U937CM and Epo acted synergistically to increase erythroid differentiation of K562. Similarly, U937CM stimulated human cord blood CFU-E growth under conditions in which Epo was limiting or in excess. Increases in Epo receptor expression on K562 cells and on CFU-E in response to EPA may mediate the effects of Epo on these cells.

Negative regulation of globin gene expression during megakaryocytic differentiation of a human erythroleukemic cell line

1991 ◽  
Vol 11 (7) ◽  
pp. 3528-3536
Author(s):  
N L Lumelsky ◽  
B G Forget
Keyword(s):  
Globin Gene ◽  
Fetal Hemoglobin ◽  
K562 Cells ◽  
Negative Regulation ◽  
Myristate Acetate ◽  
Globin Mrna ◽  
Megakaryocytic Differentiation ◽  
Gamma Globin ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line

The human erythroleukemic cell line K562 was used as a model for analysis of the mechanisms responsible for alterations in gene expression during differentiation. K562 cells normally synthesize fetal hemoglobin (gamma-globin), but treatment with tumor-promoting phorbol esters (phorbol myristate acetate and tetradecanoyl phorbol acetate) results in the loss of the erythroid phenotype of the cells and causes a shift toward a megakaryocytic phenotype. This shift involves markedly decreased production of fetal hemoglobin and de novo synthesis of a number of proteins specific for megakaryocytes. The results of this work indicate that negative regulation of fetal hemoglobin during megakaryocytic differentiation of K562 cells occurs at the level of down regulation of gamma-globin mRNA accumulation. This effect consists of at least two components: reduction in the rate of transcription of the gamma-globin gene and decrease in stability of the normally very stable gamma-globin mRNA. We have developed two assay systems that permit investigation of the transcriptional and posttranscriptional effects of phorbol myristate acetate independently from each other. These assay systems make use of a heterologous reporter gene for the transcriptional analysis and a marked gamma-globin gene for the analysis of mRNA stability. The DNA sequences located in the 3' flanking region of the A gamma-globin gene were found to be responsible for the decrease in transcription rate.

scholarly journals Expression and modulation of specific, high affinity binding sites for erythropoietin on the human erythroleukemic cell line K562

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 104-109 ◽  
Author(s):  
JK Fraser ◽  
FK Lin ◽  
MV Berridge
Keyword(s):  
Cell Line ◽  
K562 Cell ◽  
K562 Cells ◽  
Erythroid Differentiation ◽  
Receptor Expression ◽  
Target Cells ◽  
Epo Receptor ◽  
High Affinity ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line

Abstract Erythroid differentiation is mediated by several interacting factors which include the glycoprotein hormone erythropoietin (Epo), interleukin-3 (IL-3) in the mouse, and erythroid-potentiating activity (EPA) in humans. Each of these factors binds to specific cell surface receptors on responsive target cells, but the way in which these factors interact to modulate erythropoiesis is unknown. In the present study, we used the human erythroleukemic cell line K562 to examine expression and regulation of the receptor for Epo using 125I-labeled, bioactive recombinant human Epo. K562 cells expressed low numbers of a single class of high-affinity Epo receptors corresponding to 4 to 6 receptors per K562 cell (KD = 270 to 290 pmol/L). Treatment of K562 cell cultures with medium conditioned by the EPA-secreting cell line U937 (U937CM) increased receptor expression 2.6 to 3.5-fold to 13 to 17 receptors/cell (KD = 260 to 300 pmol/L). That all of the Epo receptor- potentiating activity in U937CM was accounted for by EPA was shown by a similar increase in Epo receptor expression on K562 cells with recombinant EPA. The effect of U937CM on Epo receptors was reversed by culturing cells in inducer-free medium for 3 days. Medium conditioned by the 5637 cell line had no effect on Epo receptors on K562 cells. In methylcellulose culture, U937CM and Epo acted synergistically to increase erythroid differentiation of K562. Similarly, U937CM stimulated human cord blood CFU-E growth under conditions in which Epo was limiting or in excess. Increases in Epo receptor expression on K562 cells and on CFU-E in response to EPA may mediate the effects of Epo on these cells.

scholarly journals The influence of fullerenol on antioxidative enzyme activity in irradiated human erythroleukemic cell line (K562)

2007 ◽  
Vol 61 (3) ◽  
pp. 164-166
Author(s):  
Visnja Bogdanovic ◽  
Karmen Stankov ◽  
Aleksandra Nikolic ◽  
Ivana Icevic ◽  
Slavica Solajic ◽  
...  
Keyword(s):  
Cell Culture ◽  
Superoxide Dismutase ◽  
Enzyme Activity ◽  
X Rays ◽  
Control Groups ◽  
Sod Activity ◽  
Applied Dose ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line ◽  
Total Superoxide Dismutase

Cell culture K562 samples were treated with fullerenol (C6o(OH)24) at a concentration of 10 nmol/mL and thereafter irradiated with X-rays (24Gy). The activity of gamma-glutamyltransfrease (?-GT), total superoxide-dismutase (SOD) and glutathion-peroxidase (GSH-Px) was determined 1, 24 and 48 hours after irradiation. Irradiation induces an increase in the activity of all the investigated enzymes. Fullerenol in the applied dose decreased the ?-GT activity 24 and 48 h after irradiation. The total SOD activity is increased in both pretreated groups except in the iradiated group at the 48th hour. Treatment with fullerenol before irradiation increased GSH-Px activity in irradiated groups and decreased it in the control groups.

scholarly journals Negative regulation of globin gene expression during megakaryocytic differentiation of a human erythroleukemic cell line.

1991 ◽  
Vol 11 (7) ◽  
pp. 3528-3536 ◽  
Author(s):  
N L Lumelsky ◽  
B G Forget
Keyword(s):  
Globin Gene ◽  
Fetal Hemoglobin ◽  
K562 Cells ◽  
Negative Regulation ◽  
Myristate Acetate ◽  
Globin Mrna ◽  
Megakaryocytic Differentiation ◽  
Gamma Globin ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line

The human erythroleukemic cell line K562 was used as a model for analysis of the mechanisms responsible for alterations in gene expression during differentiation. K562 cells normally synthesize fetal hemoglobin (gamma-globin), but treatment with tumor-promoting phorbol esters (phorbol myristate acetate and tetradecanoyl phorbol acetate) results in the loss of the erythroid phenotype of the cells and causes a shift toward a megakaryocytic phenotype. This shift involves markedly decreased production of fetal hemoglobin and de novo synthesis of a number of proteins specific for megakaryocytes. The results of this work indicate that negative regulation of fetal hemoglobin during megakaryocytic differentiation of K562 cells occurs at the level of down regulation of gamma-globin mRNA accumulation. This effect consists of at least two components: reduction in the rate of transcription of the gamma-globin gene and decrease in stability of the normally very stable gamma-globin mRNA. We have developed two assay systems that permit investigation of the transcriptional and posttranscriptional effects of phorbol myristate acetate independently from each other. These assay systems make use of a heterologous reporter gene for the transcriptional analysis and a marked gamma-globin gene for the analysis of mRNA stability. The DNA sequences located in the 3' flanking region of the A gamma-globin gene were found to be responsible for the decrease in transcription rate.

scholarly journals Activation of erythroid-specific promoters during anthracycline-induced differentiation of K562 cells

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2885-2890 ◽  
Author(s):  
A Aries ◽  
C Trentesaux ◽  
S Ottolenghi ◽  
JC Jardillier ◽  
P Jeannesson ◽  
...  
Keyword(s):  
Cell Line ◽  
Binding Sites ◽  
Gene Promoter ◽  
K562 Cells ◽  
Mrna Levels ◽  
Gene Promoters ◽  
Regulatory Regions ◽  
Gamma Globin ◽  
Erythroleukemic Cell ◽  
Erythroleukemic Cell Line

Anthracycline antitumor drugs such as aclacinomycin (ACM) and doxorubicin (DOX) used in subtoxic concentrations induce erythroid differentiation of the erythroleukemic cell line K562. To elucidate the possible role of erythroid genes of the erythropoietin receptor (EpoR) and the transcription factor GATA-1 in this effect, the regulatory regions of the above genes and human epsilon- and gamma-globin and porphobilinogen deaminase (PBGD) genes were fused to the firefly luciferase gene. The resulting reporter constructs were tested in a transfection assay of the erythroleukemic cell line K562 stimulated to differentiate by treatment with the anthracycline drugs ACM and DOX or hemin (HEM). The results showed activation of the tested promoters after cell treatment with ACM, but not with DOX or HEM. In contrast to the mouse EpoR gene promoter, the activity of the human EpoR gene promoter (-659/-60) in the reporter construct was not modified by addition of the first intron sequence. In ACM-treated K562 cells, EpoR gene promoter activity completely correlated with EpoR and GATA-1 mRNA levels and the degree of erythroid maturation. In addition, ACM strongly activated the erythroid gene promoters that contain GATA binding sites. Nevertheless, less activation was also observed for the GATA-1 gene promoter (-312/-31) lacking any known GATA binding sites. Insertion of the GATA-1 gene enhancer with two canonic GATA binding sites, stimulated the ACM activation effect for EpoR and GATA-1 promoter-containing constructs. Mutation of the enhancer GATA binding sites abolished this effect. All the regulatory regions tested (except gamma-globin promoter) were completely inactive in nonerythroid COS7 cells. These data indicate that (1) two structurally different anthracycline analogues, DOX and ACM, differ in their differentiation mechanisms, and (2) ACM switches on the erythroid program of K562 cells, at least in part because of interaction with a factor(s) that recognizes the GATA binding sites in the promoter region of erythroid genes leading to their activation.

scholarly journals Immunoregulation of B lymphocyte colony formation by T cell subsets in patients with chronic lymphocytic leukemia

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 294-298
Author(s):  
LA Fernandez ◽  
JM MacSween ◽  
GR Langley
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Colony Formation ◽  
B Lymphocyte ◽  
Normal Subjects ◽  
Colony Growth ◽  
Lymphocytic Leukemia ◽  
T Cell Subsets ◽  
Cell Colony

Normal B lymphocytes are activated, proliferate, and then differentiate into plasma cells and secrete immunoglobulin (Ig). We have reported that chronic lymphocytic leukemia (CLL) T4 cells help and CLL T8 cells lack suppressor effects on Ig synthesis by normal B cells (Blood 62:767, 1983). We have now explored the earlier phase, proliferation, using B cell colony formation; in semisolid media. B lymphocyte colonies from normal individuals and from patients with CLL were grown in 0.3% agarose overlayed with T cells or T cell subsets and the B cell mitogen staphylococcal protein A. Enriched T cells, OKT4 or OKT8, were obtained either by sheep erythrocyte rosettes or depletion of OKT8 or OKT4 cells by monoclonal antibody or complement, respectively. Twenty thousand B cells from normal subjects yielded 65 +/- 9, 64 +/- 7, and 19 +/- 6 colonies with autologous unfractionated T-, OKT4-, or OKT8- positive cells, respectively. This compared to 29 +/- 11, 81 +/- 11, and 15 +/- 4 colonies from patients with CLL with added autologous unfractionated T-, OKT4-, or OKT8-positive cells. To determine whether the fewer number of colonies in both normal subjects and patients with CLL with OKT8-positive cells was due to suppression or lack of help, the number of OKT4-positive cells was held constant, and OKT8-positive cells were added in increasing numbers. No suppression of colony formation could be demonstrated. Furthermore, the addition of increasing numbers of concanavalin A (Con A)-activated OKT8-positive cells did not suppress colony formation. These results suggest that the CLL T cell subsets behave in a functionally similar manner to normal T cell subsets, namely, (1) that normal and CLL B cell colony growth is helped by OKT4 cells; and (2) in contrast to immunoglobulin secretion by B cells, neither normal nor CLL OKT8 cells, unstimulated or activated by Con A, suppress B cell colony growth.

scholarly journals Joint regulation of cell size and cell number in the wing blade of Drosophila melanogaster

1997 ◽  
Vol 69 (1) ◽  
pp. 61-68 ◽  
Author(s):  
JENNIE McCABE ◽  
VERNON FRENCH ◽  
LINDA PARTRIDGE
Keyword(s):  
Drosophila Melanogaster ◽  
Significant Negative Correlation ◽  
Cell Number ◽  
Negative Association ◽  
Cell Area ◽  
Wing Area ◽  
Compensatory Control ◽  
Significant Difference ◽  
The Difference ◽  
Compensatory Regulation

We used Drosophila melanogaster to test for compensatory control of cell area and cell number in the regulation of total wing area. In two random bred wild-type base stocks collected from different geographic locations we found a negative association between the area and the number of cells in the wing blade. Three replicate lines were selected for increased or decreased wing area, with cell area maintained at the same level as in the three controls. After eight generations of selection, despite a large and highly significant difference in wing area between the large, control and small selection lines, cell area did not differ significantly between them. Rather, the difference in wing area between selection regimes was attributable to differences in cell number. Over the course of selection, the initially significant negative correlation between cell area and cell number in the wing increased, providing evidence for compensatory regulation of cell area and cell number. As a result of the increasingly negative association between the two traits, the variance in wing area declined as selection proceeded. It will be important to discover the mechanisms underlying the compensatory regulation of cell area and cell number.

A Model of Haemopoietic Cell Colony Formation

Biometrics ◽  
1972 ◽  
Vol 28 (3) ◽  
pp. 801 ◽  
Author(s):  
J. S. Maritz ◽  
E. R. Stanley ◽  
G. F. Yeo ◽  
D. Metcalf
Keyword(s):  
Colony Formation ◽  
Cell Colony
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