scholarly journals Bryostatin 1 induces differentiation of B-chronic lymphocytic leukemia cells

Blood ◽  
1989 ◽  
Vol 74 (5) ◽  
pp. 1747-1757 ◽  
Author(s):  
HG Drexler ◽  
SM Gignac ◽  
RA Jones ◽  
CS Scott ◽  
GR Pettit ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Rna Synthesis ◽  
Morphological Changes ◽  
Marine Invertebrate ◽  
Qualitative Difference ◽  
Calcium Ionophore ◽  
Lymphocytic Leukemia ◽  
Ionophore A23187 ◽  
Bryostatin 1 ◽  
Stimulatory Action

Abstract Peripheral blood cells from nine patients with B-chronic lymphocytic leukemia (B-CLL) were treated in vitro with bryostatin 1 (a macrocyclic lactone derived from a marine invertebrate). Like the phorbol ester 12- 0-tetradecanoyl-phorbol 13-acetate (TPA), bryostatin 1 activates protein kinase C (PKC), which plays a central role in the phosphatidylinositol signal transduction pathway. The effects of bryostatin 1 alone and in combination with TPA or with the calcium mobilizing ionophore A23187 were assessed by morphological appearance, cell adherence and aggregation, RNA and DNA synthesis, and immunoglobulin (Ig) production. While eight of nine B-CLL cultures remained proliferatively inert, bryostatin 1 could effectively trigger activation and differentiation of B-CLL cells in all cases as inferred by the induction of morphological changes, RNA synthesis, and monotypic Ig production. Addition of calcium ionophore A23187 to bryostatin 1- exposed cells resulted in significantly increased values for RNA synthesis and Ig production and in the acquisition of plasmacytoid morphology. Bryostatin 1 and the dual signal of bryostatin 1 plus A23187 mimicked the stimulatory action of TPA and the combination of TPA plus A23187, respectively. Overall, bryostatin 1 was less active than equivalent concentrations of TPA. This lesser efficacy may, however, reflect a quantitative rather than qualitative difference. Bryostatin 1 partially antagonized TPA-mediated effects on B-CLL cells suggesting different modes of action by the two activators. These studies indicate that bryostatin 1 has effective differentiation- inducing properties on B-CLL cells that can differentiation-inducing properties on B-CLL cells that can be accentuated by a calcium ionophore.

scholarly journals Bryostatin 1 induces differentiation of B-chronic lymphocytic leukemia cells

Blood ◽  
1989 ◽  
Vol 74 (5) ◽  
pp. 1747-1757 ◽  
Author(s):  
HG Drexler ◽  
SM Gignac ◽  
RA Jones ◽  
CS Scott ◽  
GR Pettit ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Rna Synthesis ◽  
Morphological Changes ◽  
Marine Invertebrate ◽  
Qualitative Difference ◽  
Calcium Ionophore ◽  
Lymphocytic Leukemia ◽  
Ionophore A23187 ◽  
Bryostatin 1 ◽  
Stimulatory Action

Peripheral blood cells from nine patients with B-chronic lymphocytic leukemia (B-CLL) were treated in vitro with bryostatin 1 (a macrocyclic lactone derived from a marine invertebrate). Like the phorbol ester 12- 0-tetradecanoyl-phorbol 13-acetate (TPA), bryostatin 1 activates protein kinase C (PKC), which plays a central role in the phosphatidylinositol signal transduction pathway. The effects of bryostatin 1 alone and in combination with TPA or with the calcium mobilizing ionophore A23187 were assessed by morphological appearance, cell adherence and aggregation, RNA and DNA synthesis, and immunoglobulin (Ig) production. While eight of nine B-CLL cultures remained proliferatively inert, bryostatin 1 could effectively trigger activation and differentiation of B-CLL cells in all cases as inferred by the induction of morphological changes, RNA synthesis, and monotypic Ig production. Addition of calcium ionophore A23187 to bryostatin 1- exposed cells resulted in significantly increased values for RNA synthesis and Ig production and in the acquisition of plasmacytoid morphology. Bryostatin 1 and the dual signal of bryostatin 1 plus A23187 mimicked the stimulatory action of TPA and the combination of TPA plus A23187, respectively. Overall, bryostatin 1 was less active than equivalent concentrations of TPA. This lesser efficacy may, however, reflect a quantitative rather than qualitative difference. Bryostatin 1 partially antagonized TPA-mediated effects on B-CLL cells suggesting different modes of action by the two activators. These studies indicate that bryostatin 1 has effective differentiation- inducing properties on B-CLL cells that can differentiation-inducing properties on B-CLL cells that can be accentuated by a calcium ionophore.

scholarly journals Rapid expression of protooncogenes c-fos and c-myc in B-chronic lymphocytic leukemia cells during differentiation induced by phorbol ester and calcium ionophore

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1656-1663 ◽  
Author(s):  
HG Drexler ◽  
JW Janssen ◽  
MK Brenner ◽  
AV Hoffbrand ◽  
CR Bartram
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chronic Lymphocytic Leukemia ◽  
Phorbol Ester ◽  
Messenger Rna ◽  
Calcium Ionophore ◽  
Lymphocytic Leukemia ◽  
Calcium Flux ◽  
Ionophore A23187 ◽  
Kinase C

Abstract The peripheral blood mononuclear cells from patients with B-chronic lymphocytic leukemia (B-CLL) were incubated for 0.5 h to 72 h in the presence of the phorbol ester TPA, the calcium ionophore A23187, or a combination of these reagents. Using Northern blot analysis, total cellular RNA was prepared from cells harvested at different time points and hybridized with DNA clones specific for the protooncogenes c-fos and c-myc. While untreated control cells lacked detectable amounts of messenger RNA (mRNA), increase in the level of c-fos mRNA was noted as early as 0.5 h after exposure to the inducers. Peaks of c-fos and c-myc transcript accumulation were seen at 1 h and 4 h after induction, respectively. The most effective inducer was double stimulation with TPA plus A23187. The kinetics of c-fos and c-myc mRNA accumulation in B- CLL appear to be similar to those reported for normal lymphocytes that have been either activated by physiologic external stimuli or by direct activators of protein kinase C and calcium flux (such as TPA and A23187). No direct link between oncogene expression and proliferation or differentiation parameters could be established. These results document that expression of c-fos and c-myc genes, which are among the earliest events following stimulation of the protein kinase signal transduction pathway, can be successfully induced in B-CLL cells. The data provide further evidence for the hypothesis that signal transmission downstream of protein kinase C is intact in B-CLL.

scholarly journals Synergistic action of calcium ionophore A23187 and phorbol ester TPA on B-chronic lymphocytic leukemia cells

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1536-1542
Author(s):  
HG Drexler ◽  
MK Brenner ◽  
E Coustan-Smith ◽  
RG Wickremasinghe ◽  
AV Hoffbrand
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Phorbol Ester ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Lymphocytic Leukemia ◽  
Ionophore A23187 ◽  
Prolymphocytic Leukemia ◽  
Proliferation And Differentiation

The peripheral blood mononuclear cells from 16 patients with B-chronic lymphocytic leukemia (B-CLL, n = 13), B-prolymphocytic leukemia (B-PLL, n = 2) or hairy cell leukemia (n = 1) were incubated in the presence of the phorbol ester 12–0-tetradecanoylphorbol-13-acetate (TPA) and the calcium ionophore A23187. A synergy between these inducers was found with respect to morphological changes and B cell proliferation and differentiation. A23187 used alone did not activate the cells. B-CLL cells treated with the double stimulus acquired a plasmacytoid morphology, showed significantly higher incorporation of 3H-thymidine and 3H-uridine, and produced significantly higher amounts of monoclonal immunoglobulin compared with the same cells exposed to either of the inducers alone. These results indicate that phorbol ester and calcium ionophore act synergistically on B-CLL cells to induce proliferation and differentiation. B-PLL cells responded more vigorously to the signals provided by TPA and A23187. Previous studies showed that TPA and A23187 can mimic the two physiological second messengers diacylglycerol and inositol trisphosphate in the transduction of signals leading to cell activation, proliferation, and differentiation in normal B cells. The present findings suggest that the capacity of B- CLL and B-PLL cells to differentiate in response to signals of the second messenger pathway is intact.

scholarly journals Synergistic action of calcium ionophore A23187 and phorbol ester TPA on B-chronic lymphocytic leukemia cells

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1536-1542 ◽  
Author(s):  
HG Drexler ◽  
MK Brenner ◽  
E Coustan-Smith ◽  
RG Wickremasinghe ◽  
AV Hoffbrand
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Phorbol Ester ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Lymphocytic Leukemia ◽  
Ionophore A23187 ◽  
Prolymphocytic Leukemia ◽  
Proliferation And Differentiation

Abstract The peripheral blood mononuclear cells from 16 patients with B-chronic lymphocytic leukemia (B-CLL, n = 13), B-prolymphocytic leukemia (B-PLL, n = 2) or hairy cell leukemia (n = 1) were incubated in the presence of the phorbol ester 12–0-tetradecanoylphorbol-13-acetate (TPA) and the calcium ionophore A23187. A synergy between these inducers was found with respect to morphological changes and B cell proliferation and differentiation. A23187 used alone did not activate the cells. B-CLL cells treated with the double stimulus acquired a plasmacytoid morphology, showed significantly higher incorporation of 3H-thymidine and 3H-uridine, and produced significantly higher amounts of monoclonal immunoglobulin compared with the same cells exposed to either of the inducers alone. These results indicate that phorbol ester and calcium ionophore act synergistically on B-CLL cells to induce proliferation and differentiation. B-PLL cells responded more vigorously to the signals provided by TPA and A23187. Previous studies showed that TPA and A23187 can mimic the two physiological second messengers diacylglycerol and inositol trisphosphate in the transduction of signals leading to cell activation, proliferation, and differentiation in normal B cells. The present findings suggest that the capacity of B- CLL and B-PLL cells to differentiate in response to signals of the second messenger pathway is intact.

scholarly journals Rapid expression of protooncogenes c-fos and c-myc in B-chronic lymphocytic leukemia cells during differentiation induced by phorbol ester and calcium ionophore

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1656-1663
Author(s):  
HG Drexler ◽  
JW Janssen ◽  
MK Brenner ◽  
AV Hoffbrand ◽  
CR Bartram
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chronic Lymphocytic Leukemia ◽  
Phorbol Ester ◽  
Messenger Rna ◽  
Calcium Ionophore ◽  
Lymphocytic Leukemia ◽  
Calcium Flux ◽  
Ionophore A23187 ◽  
Kinase C

The peripheral blood mononuclear cells from patients with B-chronic lymphocytic leukemia (B-CLL) were incubated for 0.5 h to 72 h in the presence of the phorbol ester TPA, the calcium ionophore A23187, or a combination of these reagents. Using Northern blot analysis, total cellular RNA was prepared from cells harvested at different time points and hybridized with DNA clones specific for the protooncogenes c-fos and c-myc. While untreated control cells lacked detectable amounts of messenger RNA (mRNA), increase in the level of c-fos mRNA was noted as early as 0.5 h after exposure to the inducers. Peaks of c-fos and c-myc transcript accumulation were seen at 1 h and 4 h after induction, respectively. The most effective inducer was double stimulation with TPA plus A23187. The kinetics of c-fos and c-myc mRNA accumulation in B- CLL appear to be similar to those reported for normal lymphocytes that have been either activated by physiologic external stimuli or by direct activators of protein kinase C and calcium flux (such as TPA and A23187). No direct link between oncogene expression and proliferation or differentiation parameters could be established. These results document that expression of c-fos and c-myc genes, which are among the earliest events following stimulation of the protein kinase signal transduction pathway, can be successfully induced in B-CLL cells. The data provide further evidence for the hypothesis that signal transmission downstream of protein kinase C is intact in B-CLL.

Growth factors and the primary cilium in BALB/c 3T3 cells

1987 ◽  
Vol 45 ◽  
pp. 830-831
Author(s):  
R. W. Tucker ◽  
N. S. More ◽  
S. Jayaraman
Keyword(s):  
Growth Factors ◽  
Primary Cilium ◽  
Cultured Cells ◽  
Morphological Changes ◽  
Calcium Ionophore ◽  
Growth Stimulation ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
3T3 Cells ◽  
Microtubule Depolymerization

The mechanisms by which polypeptide growth factors Induce DNA synthesis in cultured cells is not understood, but morphological changes Induced by growth factors have been used as clues to Intracellular messengers responsible for growth stimulation. One such morphological change has been the transient disappearance of the primary cilium, a “9 + 0” cilium formed by the perinuclear centriole in interphase cells. Since calcium ionophore A23187 also produced both mitogenesis and ciliary changes, microtubule depolymerization might explain ciliary disappearance monitored by indirect immunofluorescence with anti-tubulin antibody. However, complete resorption and subsequent reformation of the primary cilium occurs at mitosis, and might also account for ciliary disappearance induced by growth factors. To settle this issue, we investigated the ultrastructure of the primary cilium using serial thin-section electron microscopy of quiescent BALB/c 3T3 cells before and after stimulation with serum.

Effects of glucocorticoids on prostaglandin formation by human amnion

1990 ◽  
Vol 68 (6) ◽  
pp. 671-676 ◽  
Author(s):  
William Gibb ◽  
Jean-Claude Lavoie
Keyword(s):  
Calcium Ionophore ◽  
Inhibitory Effect ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Isolated Cells ◽  
Stimulatory Action ◽  
Human Amnion ◽  
Human Labor ◽  
Epidermal Growth

The human amnion may be an important source of prostaglandins involved in the onset of human labor and therefore it is important to define the factors that regulate their formation in this tissue. In the present study we demonstrate that glucocorticoids inhibit prostaglandin production by freshly isolated amnion cells. The inhibitory action of the glucocorticoids, however, changes to a stimulatory action when the cells are maintained in primary culture for a few days. For both inhibition and stimulation, concentrations of 10−8 M dexamethasone or greater were required to give significant effects, and estradiol and progesterone had no effect on the prostaglandin output of the cells. Epidermal growth factor (EGF), which has previously been found to stimulate prostaglandin output by confluent amnion cells, did not alter prostaglandin output of cells initially placed in culture. Furthermore, the stimulatory action of EGF and dexamethasone appeared additive. The calcium ionophore A23187 stimulated prostaglandin output in freshly isolated cells and accentuated the inhibitory effect of dexamethasone. These studies indicate that prostaglandin formation by human amnion during pregnancy could be regulated by glucocorticoids. These steroids are easily available to the amnion by way of cortisone conversion to Cortisol by the maternal decidua. The results also indicate that amnion is capable of responding to glucocorticoids in both a stimulatory and inhibitory fashion and whether one or both actions are of importance in vivo is a question that is as yet unresolved.Key words: prostaglandins, amnion, fetal membranes, glucocorticoids, labor, pregnancy.

Membrane fusion events in the Ca2+/ionophore-induced acrosome reaction of ram spermatozoa

1986 ◽  
Vol 81 (1) ◽  
pp. 43-63 ◽  
Author(s):  
J.E. Flechon ◽  
R.A. Harrison ◽  
B. Flechon ◽  
J. Escaig
Keyword(s):  
Plasma Membrane ◽  
Acrosome Reaction ◽  
Morphological Changes ◽  
Anterior Part ◽  
Freeze Fracture ◽  
Calcium Ionophore ◽  
Limited Area ◽  
Ionophore A23187 ◽  
Early Effect ◽  
Effect Of Treatment

An acrosome reaction was induced in ejaculated ram spermatozoa by treatment with calcium and the ionophore A23187. Samples were fixed at different times after initiation of induction, and the morphological changes within the head membranes that took place as exocytosis occurred were studied in freeze-fracture replicas. Reacted acrosomes appeared in individual spermatozoa within the calcium/ionophore-treated population at different times after the start of treatment; the first cells had reacted by 10 min, whereas some took more than 40 min to react. No changes were observed in control populations. An early effect of treatment (seen in most cells within 10 min) was the appearance of particle-free ‘clearings’ in the plasma membrane over the entire acrosomal region, with aggregation of intramembranous particles between and around these ‘clearings’. At the same time, there was an increase in the number of large particles (greater than or equal to 10 nm) within the plasma membrane over the ‘lunula’ of the equatorial segment and the anterior part of the post-acrosomal region. Fusion of the plasma and outer acrosomal membranes began in a limited area at the border between the anterior and equatorial segments of the acrosome. It then spread, following arborescent pathways, sideways along this border and forwards towards the apex of the head. This labyrinthic propagation resulted in an ‘acrosomal cap’ increasingly fenestrated towards its posterior margin. Fusion propagation over the equatorial segment was inhibited, apparently as a result of the highly ordered structure of the membranes in this region.

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