McCrady C W, Staniswalis J, Pettit G R, Howe C, Grant S
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
Br J Haematol. 1991 Jan;77(1):5-15. doi: 10.1111/j.1365-2141.1991.tb07941.x.
The effect of pharmacologic manipulation of protein kinase C (PK-C) activity on the response of committed human myeloid progenitor cells (CFU-GM) to recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF) was assessed. Coadministration of the PK-C activating agents, phorbol dibutyrate (PDBu) or bryostatin 1, with rGM-CSF resulted in a dose-dependent and, under some conditions, highly synergistic increase in the number of CFU-GM. With optimal combinations, colony formation far exceeded that which could be obtained with high concentrations of rGM-CSF alone. High concentrations of PDBu (e.g. greater than or equal to 50 nM), but not bryostatin 1, completely inhibited the CFU-GM response. These inhibitory effects could be reversed by bryostatin 1, but not by high concentrations of rGM-CSF. Bryostatin 1 also potentiated colony formation in response to rGM-CSF, and blocked the inhibitory effects of high concentrations of PDBu in bone marrow cells highly enriched for progenitors bearing the MY-10 antigen. The increase in CFU-GM induced by PDBu or bryostatin 1 was associated with little change in the morphologic type of colony observed. Continuous exposure of cells to the calcium ionophore, ionomycin (500 nM), reduced the number of granulocyte-macrophage colonies, but produced little change in the concentration-response of rGM-CSF and PK-C activating agents. Finally, the PK-C inhibitors H-7 and tamoxifen, when administered at concentrations exhibiting minimal inhibitory effects in the presence of rGM-CSF alone, led to no change or small increases in the numbers of colonies formed in response to rGM-CSF and bryostatin-1, and a substantial increase in the number of colonies formed in the presence of rGM-CSF and PDBu. These results suggest that PK-C activation may play a complex role in regulating the response of normal myeloid progenitors to growth factors such as rGM-CSF. They also raise the possibility that under some circumstances the phorbol ester PDBu may trigger events that inhibit the growth of myeloid progenitors, and that this process may be blocked by bryostatin 1.
评估了蛋白激酶C（PK-C）活性的药理调控对定向人类髓系祖细胞（CFU-GM）对重组人粒细胞-巨噬细胞集落刺激因子（rGM-CSF）反应的影响。PK-C激活剂佛波醇二丁酸酯（PDBu）或苔藓抑素1与rGM-CSF共同给药导致CFU-GM数量呈剂量依赖性增加，并且在某些条件下具有高度协同性。在最佳组合下，集落形成远远超过单独使用高浓度rGM-CSF所能获得的数量。高浓度的PDBu（例如大于或等于50 nM），但不是苔藓抑素1，完全抑制了CFU-GM反应。这些抑制作用可被苔藓抑素1逆转，但不能被高浓度的rGM-CSF逆转。苔藓抑素1还增强了对rGM-CSF的集落形成，并阻断了高浓度PDBu对富含携带MY-10抗原祖细胞的骨髓细胞的抑制作用。PDBu或苔藓抑素1诱导的CFU-GM增加与观察到的集落形态类型变化不大相关。细胞持续暴露于钙离子载体离子霉素（500 nM）会减少粒细胞-巨噬细胞集落的数量，但对rGM-CSF和PK-C激活剂的浓度-反应影响不大。最后，PK-C抑制剂H-7和他莫昔芬，当以在单独存在rGM-CSF时表现出最小抑制作用的浓度给药时，对rGM-CSF和苔藓抑素-1诱导形成的集落数量没有变化或略有增加，而在rGM-CSF和PDBu存在时形成的集落数量大幅增加。这些结果表明，PK-C激活可能在调节正常髓系祖细胞对rGM-CSF等生长因子的反应中发挥复杂作用。它们还提出了一种可能性，即在某些情况下，佛波酯PDBu可能引发抑制髓系祖细胞生长的事件，并且这一过程可能被苔藓抑素1阻断。
